Bibliothek

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1995-1999  (958)
  • 1999  (958)
  • General Chemistry  (750)
  • Rat  (115)
  • Apoptosis  (93)
  • Nuclear reactions
Materialart
Erscheinungszeitraum
  • 1995-1999  (958)
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Annals of surgical oncology 6 (1999), S. 279-285 
    ISSN: 1534-4681
    Schlagwort(e): Gemcitabine ; bcl-2 ; Pancreatic cancer ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Gemcitabine is a new nucleoside analogue that produces a clinical response in 30% of patients with unresectable pancreatic carcinoma. The cytotoxic effects of many chemotherapeutic agents occur through induction of programmed cell death (apoptosis), which is controlled by the bcl-2 gene family. We determined whether induction of apoptosis by gemcitabine in pancreatic carcinoma is associated with cellular Bcl-2 content. Methods: Four pancreatic carcinoma cell lines (MIA-PaCa-2, AsPC-1, Panc-1, and Panc-48) were screened by Western blotting for Bcl-2 protein expression. Dose-response relationships for the cytotoxic effects of gemcitabine were determined using methylthiotetrazole assays, and induction of apoptosis was confirmed by fluorescence-activated cell sorting analysis. MIA-PaCa-2 cells transfected with human bcl-2 were also analyzed for gemcitabine-induced apoptosis. Results: Pancreatic cancer cell lines expressed varying amounts of Bcl-2, and the 50% lethal dose for gemcitabine-induced apoptosis was correlated with Bcl-2 content. Furthermore, Bcl-2 overexpression was associated with a significant increase in the 50% lethal dose for gemcitabine-induced apoptosis. Conclusions: Cellular Bcl-2 content was directly correlated with the cytotoxicity of gemcitabine in pancreatic carcinoma. Therefore, routine immunohistochemical analyses may be useful in predicting gemcitabine efficacy, and patients who would likely not benefit could be spared gemcitabine administration. Furthermore, the effectiveness of gemcitabine and other chemotherapeutic agents may be increased by gene therapy-mediated alteration of bcl-2 gene family members.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 139-148 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Polyamine oxidase ; Polyamines ; Gender ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Variations in level of polyamines and their related enzymes are frequently observed in response to some treatments which affect in a different way male and female. The possibility of a gender-related difference in the oxidation of polyamines was investigated in rats by measuring the activity of polyamine oxidase, a ubiquitous enzyme of vertebrate tissues, which transforms spermine into spermidine and spermidine into putrescine. The study was carried out on thymus, spleen, kidney and liver of young rats of both sexes, and female rats showed a lower polyamine oxidase activity than male rats in all the tissues. We also found higher values of spermidine acetylation in female than male rats in thymus and liver. Owing to these gender-related differences, a higher spermidine N-acetyltransferase/ polyamine oxidase ratio was found in female than in male rats. A second gender-related difference was a higher spermidine/spermine ratio in female than in male, the only exception being the thymus. These basal differences possibly account for the gender-related differences of polyamine metabolic enzyme activities in response to some treatments, including drugs or hormones.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Osmoregulation ; Rat ; Osmolarity sensor protein ENVZ
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Although the involvement of taurine in osmoregulation is well-documented and widely accepted, no detailed mechanism for this function has been reported so far. We used subtractive hybridization to study mRNA steady state levels of genes up- or downregulated by taurine. Rats were fed taurine 100mg/kg body weight per day for a period of three days and hearts (total ventricular tissue) of experimental animals and controls were pooled and used for mRNA extraction. mRNAs from two groups were used for subtractive hybridization. Clones of the subtractive library were sequenced and the obtained sequences were identified by gen bank assignment. Two clones were found to contain sequences which could be assigned to the osmolarity sensor protein envZ, showing homologies of 61 and 65%. EnvZ is an inner membrane protein in bacteria, important for osmosensing and required for porine gene regulation. It undergoes autophosphorylation and subsequently phosphorylates OmpR, which in turn binds to the porin (outer membrane protein) promoters to regulate the expression of OmpF and OmpC, major outer membrane porines. This is the first report of an osmosensing mechanism in the mammalian system, which was described in bacteria only. Furthermore, we are assigning a tentative role for taurine in the osmoregulatory process by modifying the expression of the osmoregulatory sensor protein ENVZ.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 301-313 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Transporter ; Rat ; Brain ; Heart
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In pro- and eucaryotic life, cellular and subcellular compartments are separated by membranes and the regulated and selective passage of specific molecules across these membranes is a basic and highly conserved principle. We were interested whether taurine, a naturally occuring amino acid, would be able to induce or suppress expression of transporters with the Rationale that taurine was shown to detoxify a series of endogenous toxins and xenobiotics of various chemically non-related structures. For this purpose we used a gene hunting technique, subtractive hybridization, subtracting mRNAs of taurine-treated rat brain and heart from untreated controls. Subtracted mRNAs were then converted to cDNAs, amplified, sequenced and identified by gene bank data. We found five transporter transcripts, the phosphonate transport ATPase PHNC, multidrug transporter homolog MTH104, protein-exportmembrane protein SECD, oligopeptide transporters oppA and oppD, in the brain and two: ABC-transporter BRAF-2 and cation-transport ATPase PACS, in the heart. Homologies of the sequences found were in any case 〉50% thus permitting the identification of transporters with high probability. The biological meaning could be that a naturally occuring amino acid, taurine, modulates complex transport systems. The most prominent finding is the upregulation of a multidrug transporter transcript, explaining a mechanism for the nonselective detoxifying action of taurine.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 77 (1999), S. 189-192 
    ISSN: 1432-1440
    Schlagwort(e): Key words Thyroid ; Cell culture ; Retinoids ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Retinoids influence proliferation and differentiation in transformed thyroid cell lines. Retinoids are able to damage cells by destabilizing lysosomal membranes and induce apoptosis in certain cell lines. In normal thyrocytes retinol modulates iodine metabolism. At concentrations higher than 50×10–6 M retinoids are cytotoxic for normal (not transformed) thyroid cells. The mechanism of this cytotoxicity is unknown. We studied the effect of 7–80×10–6 M retinol on porcine follicular thyrocytes in culture. In order to differentiate between membrane-destabilizing effects and apoptosis we investigated cultures after incubation with retinol by light- and electron-microscopy and by labeling of potential nicks in the DNA helix by terminal deoxynucleotidyltransferase-dUTP mediated DNA nick end labeling. We conclude that the observed cytotoxicity is caused mainly by the induction of apoptosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 77 (1999), S. 282-293 
    ISSN: 1432-1440
    Schlagwort(e): Key words Chronic lymphocytic leukemia ; Apoptosis ; Cell growth ; Signaling ; Review
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Chronic lymphocytic leukemia is a malignant disease characterized by clonal expansion of relatively mature B-lymphocytes with a high percentage of cells arrested in the nonproliferative G0/G1 cell cycle phase. Possibly reflecting the clinical heterogeneity observed in patients, various signaling pathways may become affected during the initiation and course of this disease. This review discusses frequent alterations concerning proliferative, differentiation-inducing, and apoptotic pathways elucidated in the recent years that have improved our understanding of this disease.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    ISSN: 1432-1912
    Schlagwort(e): Key words Asphyxia ; Nitric oxide ; Electron spin ; resonance ; Adrenocorticotropin ; Resuscitation ; S-Methylisothiourea ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Anaesthetized rats, endotracheally intubated and mechanically ventilated with room air, were subjected to a 5-min period of asphyxia by turning off the ventilator. The ventilator was then turned back on and, simultaneously, the animals were treated with either the adrenocorticotropin fragment 1–24 [ACTH-(1–24), 160 µg/kg in a volume of 1 ml/kg i.v.] or an equivalent volume of saline. Nitric oxide (NO)-haemoglobin formation was detected ex vivo in arterial blood by electron spin resonance spectrometry; arterial blood pressure, electrocardiogram (ECG) and electroencephalogram (EEG) were monitored for a 60-min observation period, or until prior death. During asphyxia, there was massive formation of NO (red cell concentrations 40–80 µM), associated with a dramatic fall in mean arterial pressure and pulse pressure, marked bradycardia and ECG signs of ischaemic damage, as well as an isoelectric EEG. Treatment with ACTH-(1–24) produced a prompt (within 15 min) and long-lasting drop in NO blood levels, associated with an almost immediate (within 1 min) restoration of cardiovascular function and with a more gradual recovery of EEG, which became normal after 30–40 min; all parameters remained stable throughout the 60-min observation period. In saline-treated rats, on the other hand, there was a further increase in NO blood levels, as detected 3 min after treatment, and all died within 5–8 min. Moreover, pretreatment and treatment with S-methylisothiourea sulphate (SMT, 3 mg/kg i.v.), a relatively specific inhibitor of inducible NO synthase, inhibited NO formation, but did not affect the mortality rate (100% within 5–8 min). The present results provide the first evidence that prolonged asphyxia is associated with high blood concentrations of NO, and that the life-saving effect of melanocortin peptides in severe hypoxic conditions is associated with a complete normalization of NO blood levels. However, the lack of SMT protection in this experimental model seems to rule out the possibility that the ACTH-(1–24)-induced resuscitation is due to an effect on NO overproduction.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 359 (1999), S. 117-122 
    ISSN: 1432-1912
    Schlagwort(e): Key words Ethanol ; Restraint stress ; NMDA receptor complex ; Memantine ; Drug discrimination ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There is a large body of experimental evidence that both stress and N-methyl-d-aspartate (NMDA) receptor antagonists may alter acute behavioural effects of ethanol. Notably, an uncompetitive, low-affinity NMDA receptor antagonist, memantine, has been recently claimed to possess anti-craving properties in rats with a long-term history of ethanol consumption. The aim of the present study was to assess the effects of restraint stress and memantine on the dose-response curve of ethanol discrimination. Rats were trained to discriminate 1 g/kg ethanol from saline in the two-lever drug discrimination procedure. When ethanol discrimination was acquired, the subjects were exposed to 30-min sessions of acute restraint stress, and different doses of ethanol (0.25, 0.5 or 1 g/kg) or saline were administered. In subsequent experiments the effects of memantine (2.25 or 4.5 mg/kg) on the cueing effects of ethanol were tested. Neither the stress sessions nor memantine influenced the ethanol discrimination dose-response curve. Moreover, the stress did not alter the rate of responding. However, both doses of memantine tended to increase the rate of responding when given in combination with lower doses of ethanol (0.25–0.5 g/kg). In contrast, 4.5 mg/kg memantine decreased the response rate when combined with 1 g/kg ethanol. These results suggest that: (1) pre-exposure to acute restraint stress or memantine does not affect the dose-response curve of ethanol discrimination; (2) memantine given in combination with low doses of ethanol may stimulate operant behaviour in the food-reinforced drug discrimination procedure.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 125 (1999), S. 1-8 
    ISSN: 1432-1335
    Schlagwort(e): Key words Cell proliferation ; Apoptosis ; Cell death ; Cultured cells ; Hepatocellular carcinoma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There are conflicting results for experiments aimed at determining whether anticancer drug therapy of human hepatocellular carcinoma prolongs the survival rate effectively. The purpose of this study was to assess the effect of low concentrations of doxorubicin, mitomycin C, and ethanol on cell replication (cell number and proliferation), and cell apoptosis of cultured human hepatocellular carcinoma (Hep-G2) cells. After 1 day of exposure doxorubicin inhibited cell replication initially by 72%, but a partial recovery of the cell number was observed. Mitomycin C inhibited to the same extent but without recovery. Ethanol reduced the cell number even further, the maximum inhibition (12 days after exposure) being 96.4%. After 3 days of exposure all three agents stopped cell replication at a level of 2%–4% of the control (P 〈 0.001). Cell apoptosis was activated most strikingly by mitomycin C (5 μg/ml) after 1 day of exposure and by ethanol (150 μl/ml) after 3 days of exposure. Two-way repeated-measures analysis of variance showed statistically significant differences, with ethanol being the most significant followed by mitomycin C doxorubicin, and the control (P 〈 0.01). Thus, a low dose of ethanol combined with an exposure time of up to 3 days appears to be an effective regimen to control growth of human hepatocellular carcinoma cells in vitro. The strong induction of apoptosis by ethanol might be of additional benefit for a local application in vivo.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    ISSN: 1432-1335
    Schlagwort(e): Key words Basic fibroblast growth factor ; Cisplatinum ; Apoptosis ; Bcl-2 ; MCF-7
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Basic fibroblast growth factor (bFGF) is a classical mitogen in fibroblasts and endothelial cells. Our previous studies have demonstrated that bFGF inhibits the growth of MCF-7 human breast cancer cells. The aim of the present study was to examine the effect of bFGF on cis-diamminedichloroplatinum(cisplatin)-induced cytotoxicity in MCF-7 breast cancer cells as compared to normal endothelial cells. MCF-7/NCF cells transduced with a vector expressing the bFGF gene and overexpressing its product, and MCF-7/N2 cells transduced with the backbone vector were incubated with a combination of bFGF and cisplatin for 5 days; results were compared with those obtained with bovine aortic endothelial cells. Cell proliferation was assessed with the sulforhodamine B colorimetric cytotoxicity assay. Apoptosis was quantitatively determined by flow-cytometric analysis for DNA damage and the apoptotic death assay for DNA fragmentation, and qualitatively by electron microscopy. Reverse transcriptase/polymerase chain reaction analysis and an enzyme immunoassay were used to determine the mRNA and protein level, respectively, of the anti-apoptotic bcl-2 gene product. We found that bFGF enhanced cisplatin-induced cytotoxicity in MCF-7 breast cancer sublines. bFGF enhanced proliferation of normal endothelial cells and did not increase cisplatin-induced cytotoxicity. This effect was accompanied by down-regulation of the anti-apoptotic protooncogene bcl-2 and the enhancement of cisplatin-induced apoptosis. We suggest that the improved understanding of the role of bFGF in the differential modulation of the response of breast cancer and normal endothelial cells to chemotherapy may enable active intervention to alter the therapeutic ratio favorably in breast cancer patients.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 11
    ISSN: 1432-1335
    Schlagwort(e): Keywords Chemosensitivity ; Human gastric carcinoma ; Micrometastasis ; Apoptosis ; Circulating tumor cells ; Fluoropyrimidine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Antimetastatic effects of 5-FU and its derivative, 1-hexylcarbamoyl-5-fluorouracil (HCFU) on human gastric cancer micrometastasis and their mode of action were evaluated, using a spontaneous lung metastasis model (HY-1) in nude mice. Metastases were first detected in the lung from 4 weeks after subcutaneous transplantation, growing intravascularly and forming micrometastases at 100% incidence by 6 weeks after implantation. Lung metastasis in mice bearing subcutaneous tumors was significantly inhibited by HCFU at doses of 100–150 mg kg−1 day−1 without severe toxic side-effects, when orally administered three times per week either from week 4 or week 6 to 9 weeks after implantation. Spontaneous lung metastasis was also inhibited by the administration of 5-FU, but to lesser extent than with HCFU at equimolar low doses. Apoptosis within primary tumors and lung metastatic foci, as detected by the terminal-deoxynucleotidyltransferase-mediated dUTP nick-end labeling method, was found to be significantly enhanced by HCFU as well as 5-FU administration at doses of more than 100 mg kg−1 day−1 and 50 mg kg−1 day−1 respectively. However, proliferating activity of the metastatic foci, as evaluated by MIB-1 immunostaining, was not significantly suppressed by HCFU or 5-FU treatment. Furthermore, polymerase chain reaction analysis using human specific primers for the β-globin gene, which proved to be capable of detecting 10 tumor cells/ml mouse blood, revealed that circulating tumor cells in the peripheral blood of mice bearing primary tumors were reduced by HCFU or 5-FU administration. These results indicate that circulating tumor cells in blood and micrometastases in the lung are sensitive to these chemotherapeutic agents, and suggest that the anti-metastatic effect of these agents is mediated, at least in part, by enhanced apoptosis rather than by inhibition of cell proliferation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 12
    ISSN: 1432-1335
    Schlagwort(e): Key wordsIGF ; Apoptosis ; Transformation ; Chemosensitivity ; Signaling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Insulin-like growth factor I (IGF-I) exerts pleiotropic effects on mammalian cells via stimulation of its receptor (IGF-IR), a receptor tyrosine kinase. In vivo, IGF-I acts both as a local tissue growth factor and as a circulating hormone. In oncological research, IGF-I has received increased attention as the activated IGF-I/IGF-IR system displays mitogeneic, transforming, and anti-apoptotic properties in various cell types by stimulating distinct intracellular signaling pathways. Recent data suggest that the anti-apoptotic effect of IGF-I may mediate decreased sensitivity to chemotherapeutic drugs in vitro and in vivo. Thus, targeting the IGF-I/IGF-IR system could serve as an approach to overcome clinical drug resistance in certain tumors.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 13
    ISSN: 1432-1335
    Schlagwort(e): Key words Immunohistochemistry ; DNA repair ; Radiation-inducible response ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Immunohistochemical methods were used to determine abundance and subnuclear distribution of DNA topoisomerase I and the Bax protein in normal and excision-repair-deficient xeroderma pigmentosum (XP) fibroblasts after irradiation of cells with γ rays or UV light, or exposure to the topoisomerase I inhibitor topotecan. DNA topoisomerase I and Bax were monitored using antisera raised against the human proteins. In addition, topoisomerases IIα and IIβ were made visible with specific antibodies. In untreated cells, DNA topoisomerase I was found to occur in the cytoplasm and in nucleoli. Irradiation with γ rays (2–12 Gy) or UV light (0.3–1.2 mW/cm2) changed the staining pattern in nuclei such that a multitude of small topoisomerase-I-rich centers occurred, which were evenly distributed over the karyoplasm. Simultaneously nucleoli disintegrated. Treatment of fibroblasts with topotecan (6–100 μM concentrations) resulted in similar alterations although the changes were much more pronounced. Combinations of topotecan and γ irradiation caused additive effects. We conclude that the increase in the number of topoisomerase-I-positive spots and the high fluorescence intensity of the latter may reflect three biological processes: (i) enhanced transcriptional activity (e.g. of DNA damage response genes), (ii) tagging of damaged DNA sites for repair, or (iii) initiation of apoptosis. In separate assays using normal and XP cells, a dose-dependent increase in protein reacting with Bax antibody was observed in nuclei, following treatment with γ rays or topotecan. In addition, topotecan induced a netlike arrangement of this Bax protein in nuclei. The meshes of the net structure resembled vesicles. DNA staining with 4′,6-diamidino-2-phenylindole dihydrochloride revealed that the vesicle-type structures contained DNA. Upon further incubation with topotecan, cells showing the netlike Bax arrangement eventually died. We conclude that topotecan-induced changes made visible by nuclear Bax protein are associated with apoptosis. XP cells, when treated with topotecan, responded more readily than normal cells with both an increase in nuclear Bax protein and rearrangement of Bax, indicating that UV repair functions may be required to process DNA damage inflicted by topotecan. Monitoring of DNA topoisomerases IIα and IIβ in γ-irradiated cells with antibodies revealed a dramatic increase in the IIα form and a redistribution of the IIβ form representing fragmentation of nucleoli.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 125 (1999), S. 357-360 
    ISSN: 1432-1335
    Schlagwort(e): Key words Colorectal neoplasms ; Apoptosis ; Chemosensitivity ; p53 gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose : The p53 gene is considered one of the most important in the control of apoptosis, and its mutations have a close relationship with chemosensitivity. The aim of this work was to investigate the role of p53 in the apoptosis of colorectal cancer cells in vitro, induced by 5-fluorouracil (5-FU) and hydroxy-camptothecin (HCPT). Methods : A total of 39 colorectal cancer samples from patients were treated in vitro with 5-FU (10 μg/ml), 5-FU (10 μg/ml) + leucovorin (5 μg/ml), HCPT (0.1 μg/ml) and HCPT (0.1 μg/ml) + Salvia mitorrhiza (6 μl), using an in situ terminal deoxynucleotidyltransferase assay to detect chemosensitivity. p53 gene mutations from tumor DNA were detected, after amplification by the polymerase chain reaction of exons 5–8, by non-radioactive single-strand conformation polymorphism. Results : p53 gene mutations were observed in 43.6% (17/39) of colorectal carcinomas, when the terminal deoxynucleotidyltransferase assay was used to detect the tumor apoptotic rate. Cells with mutated p53 had lower chemosensitivity than those without (p 〈 0.01). Conclusion : Routine assessment of p53 status may be helpful in selecting patients with the wild-type p53 gene, who have a predictably better response to chemotherapy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 15
    ISSN: 1432-1335
    Schlagwort(e): Key words EGF receptor signalling ; Tyrphostin ; Apoptosis ; Colon cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Growth effects of tyrphostins A25 and AG1478 on colorectal tumor cells were studied to explore therapeutic potential. Cell number, DNA synthesis and apoptotic index were measured as growth parameters and cell-death-associated proteins Bcl-2 and Bak and protein phosphorylation were analyzed. Both tyrphostins inhibited DNA synthesis and induced apoptosis in tumor cell cultures with different patterns of activity. A25 displayed strong selectivity for the cell lines expressing high levels of epidermal growth factor (EGF), HT29/HI1 and SW480. Inhibition of DNA synthesis was efficient in all cells except T84, and the apoptotic index increased two- to fivefold. By contrast, AG1478 was highly effective in all cell lines. In addition, it caused cell loss in VACO235 adenoma cells at concentrations lower than those necessary to inhibit BrdU incorporation, reflecting preferential retention of cells actively synthesizing DNA. Induction of apoptosis was more efficient with AG1478 than with A25 (tenfold in VACO235). Insulin-like growth factor (IGF1) did not rescue cells exposed to A25 or to high concentrations of AG1478, but was effective with suboptimal amounts of AG1478. Both compounds inhibited phosphorylation of the EGF receptor as well as additional proteins. AG1478 induced expression of Bak and down-regulated Bcl-2. In summary, tyrphostins may provide alternatives for colorectal tumor treatment. Their broader range of activities and the lower susceptibility to interactions with IGF1 can be an advantage over receptor antibodies.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 16
    ISSN: 1432-1335
    Schlagwort(e): Key words Experimental pancreatic cancer ; Hormonal therapy ; Bombesin antagonist ; Somatostatin analog ; LH-RH antagonist ; EGF receptor ; Apoptosis ; AgNOR
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Reduction in receptors for epidermal growth factor (EGF) in cancers appears to be one of the principal mechanisms through which peptide hormone analogs can inhibit tumor growth. In this study, hamsters with nitrosamine-induced pancreatic cancers were treated for 8 weeks with bombesin/gastrin-releasing peptide (GRP) antagonist RC-3095, somatostatin analog RC-160 or the luteinizing hormone-releasing hormone antagonist Cetrorelix, using sustained delivery systems releasing 20, 35 and 20 μg analog/ day respectively. To establish the pattern of changes in the number and affinity of EGF receptors on tumors, groups of animals were sacrificed at regular intervals during therapy. Chronic treatment with RC-3095 or Cetrorelix resulted in an early (day 10) and sustained reduction (71% or 69% respectively) in EGF receptors on pancreatic tumors. In contrast, RC-160 decreased receptor concentration by 60% only after 20 days. Among the histological characteristics of proliferation, the decrease in argyrophilic nucleolar organizer regions, but not apoptotic and mitotic indices, showed a correlation with the fall in EGF receptors. The concentration of the receptors returned to the control level 4 days after cessation of chronic treatment with RC-3095. The effect of single injections of RC-3095, RC-160 and Cetrorelix on EGF receptors was also investigated. RC-160 decreased the number of EGF receptors on pancreatic cancers by 31% 3 h after administration, but the receptors had returned to normal level at 6 h. RC-3095 and Cetrorelix caused a 67% and 59% decline, respectively, in EGF receptors only 6 h after injection and the concentration of receptors remained low for 24 h. Thus, the pattern of down-regulation of EGF receptors in pancreatic cancers appears to depend on the peptide used for therapy. Since the antitumor effect may be the result of the fall in EGF receptors in cancers, information on the time course of changes in these receptors during treatment with these analogs may lead to an improvement in therapeutic regimens.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 17
    ISSN: 1433-0474
    Schlagwort(e): Schlüsselwörter Ataxia teleangiectatica ; Immunfunktionsstörung ; Lymphozytensubpopulationen ; Apoptose ; CD45RO ; CD45RA ; Key words Ataxia teleangiectasia ; Immunodeficiency ; Lymphocyte subset ; Apoptosis ; CD45RO ; CD45RA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Background: Can a characterisation of the lymphocyte subset in patients with ataxia teleangiectasia offer an explanation for the cellular defect of their immunfunction? Methods: In ten patients with ataxia teleangiectasia and a corresponding control group of individuals of similar age and sex, immunophenotyping was carried out by means of flow cytometric analysis and the use of monoclonal antibodies. Results: Patients with ataxia teleangiectasia showed a reduction of the number of T-cells with a decrease in the T-helper cell subset (CD3: 990/µl, p〈0.0005 and CD4: 568/µl, p〈0.0005). The number of B-cells was low (CD19: 39/µl, p〈0.005). Moreover, there was an increase in highly activated T-lymphocytes which can be seen from a higher percentage of the HLA-DR- and CD45RO-expression in patients with ataxia teleangiectasia compared to the individuals of the control group (HLA-DR: 57%, p〈0.0005 and CD45RO: 82%, p〈0.001). At the same time, the expression of CD95 (Fas/AP01) was clearly increased (CD95: 74%, p〈0.001). Interpretation: The lymphocyte subset of the patients suffering from ataxia teleangiectasia shows a significant decrease of the B- and T-cell subsets. The reduced number of T-helper cells – caused by a CD45RA-cell loss – leads to a change in the relation „RA/RO”. It is possible that there is a link between the imbalance of „RA/RO”, the increase of highly activated T-lymphocytes and the higher expression of CD95 (Fas/APO1).
    Notizen: Zusammenfassung Fragestellung: Können durch eine Charakterisierung der Lymphozytensubpopulationen bei Patienten mit Ataxia teleangiectatica Rückschlüsse auf den zellulären Defekt der Immunfunktionsstörung gezogen werden? Methodik: Mit Hilfe der Durchflußzytometrie und des Einsatzes monoklonaler Antikörper führten wir eine Immunophänotypisierung bei jeweils 10 Patienten mit Ataxia teleangiectatica und eines bezüglich des Alters und des Geschlechts gleichverteilten Kontrollkollektivs durch. Ergebnisse: Die Patienten mit Ataxia teleangiectatica zeigten verminderte T-Zell-Zahlen mit Abnahme der T-Helferzell-Subpopulationen (CD3: 990/µl, p〈0,0005 und CD4: 568/µl, p〈0,0005). Auch die B-Zell-Zahl war erniedrigt (CD19: 39/µl, p〈0,005). Die T-Lymphozyten befanden sich darüber hinaus vermehrt im aktivierten Zustand, erkennbar an einer prozentual erhöhten HLA-DR- und CD45RO-Expression (HLA-DR: 57%, p〈0,0005 und CD45RO: 82%, p〈0,001) sowie an einer Verschiebung der Relation „RA/RO” zugunsten der „RO”-Expression. Gleichzeitig war die Expression von CD95 (Fas/APO1) deutlich gesteigert (CD95: 74%, p〈0,001). Schlußfolgerung: Die Veränderungen der Lymphozytensubpopulationen zeigen bei den Patienten mit Ataxia teleangiectatica eine verminderte B- und T-Zell-Zahl. Die CD4-Lymphopenie – verursacht durch einen CD45RA-Zellverlust – bedingt eine Verschiebung der Relation „RA/RO”. Möglicherweise besteht ein Zusammenhang zwischen der Störung der Homöostase „RA/RO” und dem erhöhten Aktivierungsgrad der Zellen sowie der vermehrten CD95(Fas/APO1)-Expression.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 18
    ISSN: 1437-7799
    Schlagwort(e): Key words Desferrioxamine ; Cadmium ; Metallothionein ; Nephrotoxicity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background. Desferrioxamine (DFO) a chelating agent, is used to treat metal toxicity caused by iron and aluminum in patients on hemodialysis. We hypothesized that DFO could also be used to treat cadrium-induced nephropathy. Animal experiments were therefore performed to explore whether DFO removed cadmium (Cd) from the kidneys of rats with a Cd burden. Methods. Rats received subcutaneous injections of Cd chloride (3 mg Cd/kg per day, days 0–7) followed by DFO (50 mg/kg per day, days 8–14). Levels of Cd were determined in liver, kidneys, and plasma. Enzymes assays and histopathological examination were performed in kidneys. Results. In liver, Cd injections elevated Cd levels; subsequent injections of DFO lowered the Cd levels compared with levels after injections of Cd alone. In kidneys, Cd injections increased levels of total Cd and Cd bound to cellular membranes (Mem-Cd), and decreased leucine aminopeptidase (LAP) activity (a marker of renal injury); subsequent injections of DFO elevated levels of total Cd and Mem-Cd, and lowered LAP activity compared with fundings after the injection of Cd alone. After the injections of Cd alone and DFO following Cd the renal levels of Cd were below the critical concentration required to cause renal injury, since no histopathological changes were observed in the kidney. Conclusion. DFO administration to Cd-burdened rats removed Cd from the liver, but led to accumulation of Cd in the kidneys, particularly in the cellular membranes. These results suggest that if DFO is given long-term to Cd-burdened patients, the Cd level in kidneys, particularly in renal cellular membranes, could reach concentrations that could cause manifest renal injury.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 19
    ISSN: 1437-9813
    Schlagwort(e): Key words Congenital diaphragmatic hernia ; Rat ; Glucocorticoid ; Antenatal therapy ; Insulin-like growth factor I and II ; Reverse transcription-polymerase chain reaction (RT-PCR)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There is increasing evidence to suggest that insulin-like growth factors (IGF) I and II play a crucial role in fetal lung development. Expression of IGF-I and II has been demonstrated to be predominant during fetal life and decreases prior to birth. Antenatal glucocorticoids are reported to improve lung immaturity. The aim of this study was to investigate the effect of antenatal glucocorticoid administration on IGF-I and II expression in nitrofen-induced congenital diaphragmatic hernia (CDH) in rats. A CDH model was induced in pregnant rats following administration of 100 mg nitrofen on day 9.5 of gestation (term = 22 days). Dexamethasone (0.25 mg/kg) was given intraperitoneally on days 18.5 and 19.5 of gestation. Cesarean section was performed on day 21. The fetuses were divided into three groups: I, normal controls; II, nitrofen-induced CDH; and III, nitrogen-induced CDH with antenatal dexamethasone treatment. mRNA was extracted from whole lung and a reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate the relative amounts of IGF I and II mRNA. Levels of mRNA were expressed as a ratio of the band density divided by that of β-actin, a housekeeping gene known to be expressed at a constant level. Immunohistochemistry using anti-rat IGF I and II antibody was also performed in each group. Levels of IGF I mRNA were significantly increased in group II (0.50 ± 0.08) compared to group I (0.34 ± 0.10) or group III (0.32 ± 0.06) (P 〈 0.05). Levels of IGF II mRNA were also significantly increased in group II (0.95 ± 0.20) compared to group I (0.42 ± 0.07) or group III (0.31 ± 0.09) (P 〈 0.05). Strong IGF I and II expression was observed in the hypoplastic CDH lung (group II), mainly in the bronchiolar epithelium. IGF I and II expression in group I and III lungs was either absent or weak. The finding of significant reductions in IGF I and II mRNA and protein levels in dexamethasone-treated CDH lung suggest that dexamethasone may accelerate the fetal stage of lung development.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 201-205 
    ISSN: 1437-9813
    Schlagwort(e): Key words Esophagus ; Atresia ; Notochord ; Adriamycin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Esophageal atresia (EA) is often accompanied by vertebral defects and other anomalies. The adriamycin rat model of EA has disclosed the embryology of the malformation and shown that the vertebrae and notochord are also abnormal. This study describes the nature of notochord malformations in rat embryos exposed to adriamycin. Time-mated rats received either 1.75 mg/kg adriamycin or vehicle i.p. on gestational days (E) 6 to 9; E-12, E-12.5, and E-13 embryos were harvested, embedded in paraffin, and serially sectioned at 3 μm in transverse plane from the head to the stomach for subsequent PAS staining. The findings in both groups were compared at the three endpoints. Control embryos had neither tracheoesophageal nor notochord malformations. On day 12, only 11/36 adriamycin embryos were normal; 7/36 had abnormal notochords, 11/36 had EA, and 7/36 had both. The corresponding figures for 12.5 days were 12/27, 0/27, 7/27, and 8/27 and those for the day 13 7/23, 5/23, 3/23, and 8/23. The malformed notochords were thickened, bifurcated, or trifurcated in the sagittal plane. The simultaneous presence of notochord and esophageal malformations suggests a direct link between both defects, but our observation of isolated occurrence of both shows that they reflect two expressions of the profound disturbance of embryonic para-axial organization responsible for the cluster of malformations rather than a cause-effect association.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 457-460 
    ISSN: 1437-9813
    Schlagwort(e): Key words Blunt testicular injury ; Rat ; DNA flowcytometry ; Antisperm antibodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Injury to the testis breaching the tunica albuginea is known to affect fertility. Blunt testicular trauma with an intact tunica albuginea has been reported to have no effect on contralateral testicular histology and Johnsen testicular maturation score. However, sensitive techniques like DNA flowcytometry have not been utilized so far to evaluate contralateral testicular germ-cell changes. Sixty-four male Wistar rats aged 20 days were randomized into groups I (control), II (unilateral blunt testicular trauma, UBTT), III (UBTT and excision of ipsilateral testis at 6 h), and IV (UBTT and cyclosporine for 30 days). Fertility, DNA flowcytometry of contralateral testicular tissue, and anti-sperm antibodies (ASA) were evaluated. Fertility and haploid-cell percentage of the contralateral testis were significantly decreased compared to controls in early adulthood (100 days). Around 150 days of age, as ASA decreased significantly, fertility and contralateral testicular haploid-cell population recovered and were comparable to the controls. Excision of the traumatized testicle around 6 h after injury or administration of cyclosporine for 30 days protected fertility and the contralateral testis. In contrast to group II rats, ELISA for ASA was negative in group III and IV rats. UBTT affects the contralateral testis and fertility. ASA mediate this damage. Orchidectomy performed around 6 h after trauma or short-term cyclosporine therapy prevents the damage.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Clinical and experimental nephrology 3 (1999), S. 254-260 
    ISSN: 1437-7799
    Schlagwort(e): Key words Low density lipoprotein ; Apoptosis ; Malondialdehyde ; TGFβ1 ; Unilateral ureteral obstruction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background. To test the hypothesis that oxidized low density lipoprotein (oLDL) is involved in the renal injury of obstructive nephropathy, male Sprague-Dawley rats weighing 125–150 g were used. Methods. Three days after arrival, the rats were randomly assigned to undergo: (1) sham operation, (2) left unilateral ureteral obstruction (UUO), or (3) reversal of the unilateral ureteral obstruction (R-UUO). Seven days after the reversal operation or 10 days after the sham or UUO procedure, all animals were killed by exsanguination under anesthesia, with blood taken from the abdominal aorta. LDL was prepared by gradient ultracentrifugation and used immedi-ately after isolation. Rat mesangial cells were utilized with an LDL concentration of 100 μg/ml/protein in the media. After 72 h, cell survival was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) method. Cell survival was determined by comparing the optical density between the control wells and the experimental wells. In order to investigate the mechanisms of injury and repair of obstructive nephropathy, data for kidney apoptosis, malondialdehyde (MDA), and transforming growth factor β1 (TGFβ1) mRNA were obtained in the sham-operated, UUO, and R-UUO groups. Results. Our results showed that LDL malondialdehyde during UUO was increased 87% over baseline values (P 〈 0.005). With R-UUO, the oxidized LDL dropped 23% from the peak values during UUO (P 〈 0.005), but was still different from that of the baseline values (P 〈 0.025). Rat mesangial cell survival, after 72 h exposure to oLDL, inversely correlated to oLDL cytotoxicity and showed a 14% drop during UUO compared with sham-operated animals (P 〈 0.01). Cell survival increased 11% after R-UUO (P 〈 0.02) and was not different from control values (P = NS). The apoptotic counts by the TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling) technique showed significant increases during UUO and a noticeable reduction after R-UUO. Conclusion. Our data support the proposition that UUO stimulates oxidation of LDL. The cytotoxicity of oLDL plays a significant role in the injury of UUO. A decrease in cytotoxicity was associated with the repair in R-UUO. Our observations that apoptosis follows this same pattern, point to the importance of apoptosis in the injury and repair of obstructive nephropathy. Future studies to interrupt these processes of injury may lead to novel treatment modalities in reversing the injury and hastening the repair of obstructive nephropathy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 243-247 
    ISSN: 1437-9813
    Schlagwort(e): Key words Wilms' tumo ; Apoptosis ; Bcl-2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Wilms' tumor (WT) usually has a good outcome, although a poor prognosis is often related to more advanced stages and anaplastic features. Apoptosis occurs with variable frequency in malignant tumors, and may have a role in reducing their growth rate. The bcl-2 proto-oncogene inhibits apoptosis, and the consequent increase in the number of cells may play a role in the development of tumors. The aim of this study was to analyze the role of apoptosis and bcl-2 expression in WT. Twenty-six resected WT specimens were studied; 12 patients had stage I tumor, 4 stage II, 5 stage III, 3 stage IV, and 2 stage V. Twenty-three tumors were classified as favorable histology (FH) and 3 as unfavorable (UH). The mean follow-up was 34 months; 22 patients were alive and 4 were dead (2 with FH: 1 stage III and 1 stage IV, and 2 with UH stages 4). Apoptosis was detected by the in-situ end-labelling technique; bcl-2 expression was detected by immunohistochemistry. An apoptotic index (AI) was calculated as the ratio of apoptotic to normal cells in each specimen. The AI was lower in higher tumor stages, with a significant difference between stages I and IV (P 〈 0.05). In cases with UH, Al was lower than in tumors with FH (P 〈 0.01). The AI was also lower in patients who died than in those who survived (P 〈 0.01). In all specimens no correlation between AI and bcl-2 expression was observed. Progression to advanced stages of WT and a poor prognosis f anaplastic tumors may be linked with disruption of the mechanisms that control apoptosis. Bcl-2 does not play a role as a regulator of apoptosis in WT, other oncogenes and tumor-suppression genes may be more involved in inhibiting apoptosis in WT.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 24
    ISSN: 1437-773X
    Schlagwort(e): Key words Epithelial rest of Malassez ; Cell ; cell interaction ; Extracellular matrix ; In vitro ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The present study investigated how cell plating density and extracellular matrix protein influence cell survival of epithelial rests of Malassez (ERM) in vitro. ERM cells were plated on culture dishes coated with laminin (LM), type IV collagen (type IV), or fibronectin (FN), or on noncoated dishes, (Non) at a cell density of 2 × 104–1 × 105/ml in a nonserum culture medium. XTT assays were performed to calculate the number of cells attached on the substrata after 6, 24, 48, and 72 h. Mean cell numbers were calculated, and significant differences were determined using ANOVA. When epithelial cells were cultured on various matrices at a cell density of less than 2 × 104/ml, the cells did not grow and then fell into apoptotic cell death, which was confirmed by transmission electron microscopy. The cell number was significantly increased in cells plated on FN compared to those on Non at a cell density of 4 × 104/ml–8 × 104/ml. These results suggest that both extracellular matrix proteins and cell–cell interactions may contribute to prevent apoptosis of ERM in vitro. Cell–cell interactions may be a more important factor than exogenous extracellular matrix proteins for the survival of ERM cells in vitro.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Journal of infection and chemotherapy 5 (1999), S. 139-143 
    ISSN: 1437-7780
    Schlagwort(e): Key words Fas ; ADR ; Bladder cancer ; Synergy ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Fas and Fas ligand play an important role in cytotoxic T lymphocyte-mediated cytotoxicity. Like Fas ligand, anti-Fas monoclonal antibody (mAb) induces apoptosis of cells expressing Fas and mimics tumor necrosis factor-α (TNF-α) in its cytotoxic activity, but not in regard to other TNF-α-mediated activities. Since combination treatment with TNF-α and some anticancer chemotherapeutic agents results in synergistic cytotoxicity against various cancer cells, anti-Fas mAb may also synergize with anticancer agents in exerting cytotoxicity. The present study examined this hypothesis using bladder cancer cells. Cytotoxicity was examined by a 1-day microculture tetrazolium dye assay. Treatment of T24 cells with anti-Fas mAb in combination with mitomycin C, methotrexate, or 5-fluorouracil did not overcome their resistance to these agents. However, combination treatment with anti-Fas mAb and adriamycin (ADR) resulted in a synergistic cytotoxic effect on T24 cells, three other bladder cancer lines, and fresh bladder cancer cells derived from four patients. Treatment with ADR enhanced the expression of Fas on T24 cells. The expression of P-glycoprotein was not affected by the antibody-mediated sensitization. This study showed that combination treatment of bladder cancer cells with anti-Fas mAb and ADR can overcome their resistance and that the upregulation of Fas expression by ADR may play a role in the enhanced cytotoxicity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 26
    ISSN: 1437-773X
    Schlagwort(e): Key words Hepatocellular carcinoma ; Apoptosis ; Fas protein ; Bcl-2 protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Because the induction of apoptosis in cancer cells is very important in clinical management, it is useful to examine the association with the Fas–Fas ligand pathway and Bcl-2 protein family in apoptosis. We morphologically examined the expression of Fas and Bcl-2 proteins and induction of apoptosis by anti-Fas in four human hepatocellular carcinoma cell lines, PLC/PRF/5, Huh-6, and Huh-7, as well as OCUH-16, which was originally established in our university. Fas protein was expressed in 96% of OCUH-16 cells in cytoplasm, 24% of PLC/PRF/5 cells, 20% of Huh-6 cells, and no Huh-7 cells. Bcl-2 protein was expressed in 43%–72% of cells in cytoplasm and nuclei of the four lines examined. Administration of anti-Fas induced apoptosis in about 40% of OCUH-16 cells, but did not induce apoptosis in the other three cell lines. In conclusion, an original cell line, OCUH-16 cells, expressed Fas and Bcl-2 proteins and underwent apoptosis following treatment with anti-Fas, but the other three cell lines examined did not undergo apoptosis. OCUH-16 cells are thus very useful for the study of apoptosis and molecules related to apoptosis at the levels of cell-surface receptors and intracytoplasmic regulation of apoptosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 27
    ISSN: 1437-9813
    Schlagwort(e): Key words Unilateral undescended testis ; Rat ; Testicular injury ; DNA flowcytometry ; Anti-sperm antibody
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study was designed to evaluate whether creation of a unilateral undescended testis (U/L UDT) in rats by direct fixation of the testis can lead to changes in the contralateral (C/L) descended testis, and if so, whether this inherent problem of the model could be eliminated by anchoring the divided gubernaculum to indirectly fix the testis. Thirty male newborn rats were divided into three groups of 10 each and the procedure done on the 2nd day of life to create U/L UDT according to the group allocated: group I: sham-operated; group II: anchoring the gubernaculum after gubernaculectomy; group III: Direct suture fixation of the testis. Fertility, C/L testicular weight (TW), Johnsen score, seminiferous tubular diameter (STD), DNA flowcytometry, and serum anti-sperm antibodies (ASA) were studied. Fertility, C/L TW, Johnsen score, STD, and haploid cell population were significantly reduced in group III compared to group II, while significantly higher titers of ASA were found in group III. Gubernaculectomy and anchoring the gubernaculum to the anterior abdominal wall is a better technique of creation of experimental UDT, as direct fixation of the testis is potentially detrimental to the C/L normal, descended testis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 28
    ISSN: 1437-7772
    Schlagwort(e): Key words Ovarian cancer ; Apoptosis ; IL-6 ; CDDP ; Taxol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background. Apoptosis is a cascade of events that is regulated by many factors. We studied the effects of interleukin-6 (IL-6) on chemotherapy-induced apoptosis in three human ovarian cancer cell lines (JV, GG, and NF). Methods. Cells were treated with the anticancer drugs cis-diamminedichloroplatinum (II) (CDDP) and paclitaxel (Taxol; Bristol-Myers Squibb Pharmacessticals, Noble Park, Australia) over a period of 72 h. The treatments were repeated in combination with human recombinant IL-6 or anti-IL-6 monoclonal antibody (anti-IL-6 mAb). The induction of cell death was examined by morphology and by internucleosomal DNA fragmentation. Results. Reduced cytotoxicity and fewer apoptotic cells were observed after treatment with CDDP or Taxol combined with IL-6 compared with treatment with CDDP or Taxol alone. However, treatment with CDDP or Taxol combined with anti-IL-6 mAb enhanced the cytotoxic effects of the drugs and increased the number of apoptotic cells. These findings indicated that apoptosis caused by CDDP or Taxol was influenced negatively by high doses of IL-6. Conclusion. The use of CDDP or Taxol combined with anti-IL-6 mAb may have therapeutic value for patients with ovarian cancer.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 29
    ISSN: 1432-2307
    Schlagwort(e): Key words Pyruvate kinase isoenzymes ; N-Nitrosomorpholine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The expression of the pyruvate kinase (PK) isoenzymes L and M2 was analysed in the livers of rats treated with the hepatocarcinogenic agent N-nitrosomorpholine (NNM) in the drinking water. In control animals L-PK expression was restricted to liver parenchymal cells, whereas M2-PK was detected in bile duct epithelial, blood vessel wall, endothelial and Kupffer cells. In rats treated with NNM proliferating oval cells were consistently L-PK negative and M2-PK positive, while the ductal cells of cholangiofibroses were clearly L-PK positive and coexpressed M2-PK. However, no morphological differentiation of ductal cells into hepatocyte-like cells was observed. In the clear and acidophilic cell foci storing glycogen in excess strong staining for L-PK was observed. In glycogen-poor foci induced by NNM a shift from L-PK to M2-PK expression takes place.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 30
    ISSN: 1432-2307
    Schlagwort(e): Key words Anencephaly ; Thymic hyperplasia ; CD99 ; Apoptosis ; Aggregation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In a significant proportion of cases, anencephaly is associated with thymic enlargement, suggesting a possibility that anencephalic fetuses have a functional disturbance in thymocyte differentiation and development. In this report, we demonstrated that CD99 expression was consistently reduced in cortical thymocytes of all anencephalic fetuses. In addition, the CD99-dependent aggregation of immature cortical thymocytes was almost completely impaired and apoptosis of thymocytes was markedly reduced in several cases. These results are in agreement with previous findings that CD99 regulates the aggregation and apoptosis of various types of cells. These data strongly suggest that functional disturbance of thymocytes and thymic hyperplasia are related to the reduced expression of CD99 molecule in anencephalic fetuses.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 31
    ISSN: 1432-2307
    Schlagwort(e): Key words Medullary thyroid carcinoma ; Basement membrane ; Laminin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Medullary thyroid carcinoma (MTC) originates from C cells, which secrete calcitonin (CT), their specific marker. C cells are located in contact with the basement membrane (BM) of the thyroid follicles, which is partly made up of the laminin-2 isoform synthesized by thyrocytes. During oncogenesis, proliferation of the C cells, invading the centre of the follicles, leads to a break in their normal contact with the BM. As specific interactions of cells with BM components, especially laminins, are important for proliferation and differentiation, we investigated the relationships of normal and neoplastic C cells with laminin in the Wag/Rij rat model of human MTC. Immunocytochemical studies showed a progressive loss of the laminin layer underlying the hyperplastic C cell nodules around the large dedifferentiated tumours. The α2, β1 and γ1 chains of the laminin-2 isoform were synthesized and secreted by rat MTC 6–23 cell cultures and the tumours induced by subcutaneous injection of these cells. In situ hybridization combined with anti-CT immunocytochemistry showed a low expression of α2 mRNA on differentiated C cells and thyrocytes, but an overexpression on immunonegative spontaneous MTC and induced intrathyroid tumours. The high level of α2 gene expression, together with tumour dedifferentiation, suggests a relationship with malignancy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 27 (1999), S. 41-47 
    ISSN: 1434-0879
    Schlagwort(e): Key words Ureter ; Histology ; Polyuria ; Diabetes mellitus ; Nephrectomy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The influence of increased functional load on the macroscopical and histological appearance of the ureter was investigated. Sixty rats were divided into five groups: (1) sucrose-fed rats with non-osmotic polyuria; (2) diabetic rats with osmotic polyuria; (3) uninephrectomized rats; (4) sham-operated control rats; and (5) control rats. The 24-hour urinary volume was measured on days 7, 14 and 21. Growth of the kidney, ureter and bladder was investigated and the histological appearance of the ureter was further evaluated. Diabetic and sucrose-fed rats had comparable polyuria with a seven-fold increase in urinary output. The urinary volume for the remaining kidney was doubled in uninephrectomized rats. After 3 weeks, diabetic rats had increased weight of the kidney, ureter and bladder, sucrose-fed rats had increased weight of the bladder, whereas uninephrectomized rats had increased weight of the kidney and ureter. The cross-sectional area (CSA) of the ureter wall from control rats increased from the proximal to the distal portion. The size of the whole ureter from diabetic rats was dramatically increased, the CSA of the wall of the distal ureter portion being four times that of the controls. The CSA of the ureter wall from sucrose-fed rats was increased only in the distal portion, whereas the ureter from uninephrectomized rats was increased only in the proximal portion. The results demonstrate the importance of differentiating between different portions of the rat ureter when examining histological sections of this organ. Moreover, polyuria per se is shown to induce growth of the bladder and of the adjacent distal part of the ureter, whereas uninephrectomy and diabetes caused growth of the kidney and the upper parts of the ureter, in addition to the growth induced by polyuria.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 33
    ISSN: 1434-0879
    Schlagwort(e): Key words Nonbacterial prostatitis ; Animal model ; Partial urethral obstruction ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The pathogenesis of nonbacterial prostatitis (NBP) is not understood mainly due to the lack of appropriate experimental models. We developed a new experimental model of NBP by inducing a partial obstruction of the urethra (PUO) in the rat. Male Wistar rats aged 12 weeks were used. PUO was produced by a nylon ligature on the urethra over a rubber tube. The tube was slipped out after the ligature had been tied. Two rats were examined histologically 6 h, 1 day, 3 days and 7 days after PUO. In another group, two rats were killed at 1, 3 and 7 days after the release of the PUO that had been left in place for 3 days. On day 3, another eight rats with PUO and eight control rats had 2 ml of urine in the bladder replaced by the same volume of lucifer yellow (LY; 10 μg/ml, MW 500), microperoxidase (MP; 20 μg/ml, MW 1900), horseradish peroxidase (HRP; 10 μg/ml, MW 40 000), or saline as control, respectively. Lymphocytic infiltration and interstitial edema were noted in the prostate following PUO, being most prominent on day 3. After the release of the PUO, these inflammatory changes gradually disappeared. Only LY was noted within the prostatic stroma of the rats 2 h after bladder instillation. Intraprostatic urinary reflux may be an etiologic factor in NBP. The present study showed that lower urinary tract obstruction caused NBP in the rat. Penetration of prostatic tissue by low-molecular-weight substances in the urine may trigger NBP.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 27 (1999), S. 476-482 
    ISSN: 1434-0879
    Schlagwort(e): Key words Urinary bladder ; Enterocystoplasty ; Cecocystoplasty ; Innervation ; Nerve growth ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Incorporation of bowel into the bladder (enterocystoplasty) has been widely used to increase bladder capacity. It has been reported by others that the response of smooth muscle from the cystoplastic segment of the intestine shifts from that of the intestine (relaxation to α-agonists and ATP) to that of the bladder (contraction to α-agonists and ATP). This suggests a functional integration of the intestinal muscle into the bladder; the mechanisms are unknown. The aims of the present study were (1) to elucidate if there are signs of bladder nerves sprouting across the anastomosis into the intestinal segment, and (2) to study what happens with the intrinsic innervation of the intestinal segment. As a model, we used cecocystoplasty in rats. The bladder was opened and a patch of cecum with intact vascular supply was anastomosed to the bladder. After two to 11 months the rats were sacrificed and the bladders mounted as wholemounts and stained for acetylcholinesterase-containing nerves, or embedded in paraffin for histology. A pronounced degeneration of the myenteric plexus was found in the cecal segments. In some areas, this had proceeded to the extent that the ganglia were isolated ovoid lumps of cells with no apparent connection to other ganglia. Areas lacking ganglia and nerve trunks but still with muscle could be found in all specimens. Abundant axon bundles were demonstrated sprouting from the cut bladder nerves close to the anastomosis. The bundles spread out in a fan-like pattern or were organized as fewer thicker nerves. There were many nerve bundles entering the cecal segment where they branched and the diameter decreased till they no longer became visible. Some nerves reached surviving lumps of myenteric ganglion cells. The results show that the bladder nerves sprout into the anastomosed cecal segment. It is reasonable to assume that these nerves are responsible for the changes in receptor pharmacological properties of the cecal smooth muscle towards that of bladder muscle.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Mund-, Kiefer- und Gesichtschirurgie 3 (1999), S. 210-212 
    ISSN: 1434-3940
    Schlagwort(e): Schlüsselwörter Plattenepithelkarzinom ; Tumorneoangiogenese ; Apoptose ; Key words Squamous cell carcinoma ; Tumor neoangiogenesis ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Paclitaxel and docetaxel are potent drugs that are effective in the treatment of malignant tumors. The cytotoxic action of these drugs is not fully understood, but it appears to be mediated mainly through mitotic arrest and subsequent apoptosis. Because no information is available on the antiangiogenesis action of docetaxel, the investigations were performed to determine whether inhibition of neoangiogenesis plays a role in docetaxel’s antitumor efficacy. Four different mouse tumors, two squamous cell carcinomas (SCC-IV; SCC-VII) and two adenocarcinomas (MCA-4; MCA-29) were assayed for angiogenic activity using the in vivo i.c. angiogenesis assay. Tumor cells (5 × 105) were injected i.c. into the skin flap over the abdominal wall, and the number of new blood vessels at the tumor cell injection site was determined 2, 4, 6, 8, 10 and 12 days later. The mice were treated with docetaxel (Taxotere – 31.3 mg/kg i.v.) 1 or 4 days after tumor cell injection. The number of new blood vessels increased with time. Docetaxel reduced the number of newly formed blood vessels in MCAs, but not in SCCs. The reduction was associated with slower tumor growth. In a separate set of experiments we observed that docetaxel’s inhibitory effect on the two MCAs was histologically associated with massive tumor cell destruction by means of both apoptosis and necrosis. This was not observed for the two SCCs. Since no reduction in blood vessels occurred in tumors unresponsive to docetaxel, the inhibition of neoangiogenesis in docetaxel-responsive tumors was likely the result of a decrease in angiogenic stimuli due to docetaxel’s destruction of tumor cells.
    Notizen: Die zytotoxische Aktivität der Taxane Paclitaxel und Docetaxel ist zum jetzigen Zeitpunkt noch nicht vollständig erklärt. Diese, zur Behandlung maligner Tumoren eingesetzten antineoplastischen Chemotherapeutika, scheinen jedoch weitgehend über die Blockierung der Mitose und die nachfolgende Induktion der Apoptose zu wirken. Über eine evtl. Hemmung der Neoangiogenese, wie sie kürzlich für Paclitaxel beschrieben wurde, liegen für Docetaxel noch keine Studienergebnisse vor. Es wurde deshalb untersucht, ob die therapeutische Aktivität von Docetaxel zur Hemmung der Neoangiogenese im Tumor beitragen kann. 4 murine Tumoren, 2 Plattenepithelkarzinome (SCC-VII; SCC-IV) und 2 Adenokarzinome (MCA-4; MCA-29), wurden in einem quantitativen intrakutanen In-vivo-Angiogenese-Assay experimentell untersucht. 5 · 10 5 Tumorzellen wurden in einen Abdominallappen der Maus injiziert. Die Anzahl neuformierter Blutgefäße und das Tumorwachstum wurden im 2tägigen Intervall über einen Zeitraum von zwischen 10 und 14 Tagen bestimmt. 2 Behandlungsgruppen wurde am 1. oder 4. Tag nach der Tumorzellinokulation Docetaxel (Taxotere – 31,3 mg/kg) i.v. injiziert. Die Plattenepithelkarzinome waren gegenüber der Therapie mit Docetaxel nicht sensibel, während die Adenokarzinome mit einer Abnahme der Gefäßzahl und einer Reduktion des Tumorvolumens reagierten. Histologisch zeigten die Adenokarzinome außerdem eine massive Tumorzelldestruktion durch Apoptose und Nekrose. Da die gegenüber Docetaxel nichtsensiblen Tumoren (Plattenepithelkarzinome) nicht mit einer Abnahme der Gefäßzahl reagierten, ist der beschriebene Effekt in den Adenokarzinomen am ehesten als indirekte Wirkung von Docetaxel zu werten. Die Tumorzelldestruktion führte in den betroffenen Tumoren zu einer verminderten Freisetzung endothelialer Mitogene wie VEGF und bFGF und zur Hemmung der Tumorneoangiogenese.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Urological research 27 (1999), S. 174-179 
    ISSN: 1434-0879
    Schlagwort(e): Key words Apoptosis ; Ischemia-reperfusion ; Blood flow ; Ischemia ; Prostate ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The mechanisms involved in the castration-induced involution of the ventral prostate (VP) are not fully understood. It was recently reported that castration decreases blood flow in the VP in rats and that this occurs before the apoptotic involution of the organ. However, it is unknown whether a decrease in blood flow may trigger apoptosis in the VP, and this was therefore examined in this study. The right iliac artery was clamped for 1 h in adult male rats. After 24 h of reperfusion, the VPs were frozen or fixed. In situ end-labeling (ISEL) was used to identify apoptotic cells, and testosterone repressed prostatic message-2 (TRPM-2) was measured. Proliferating cell nuclear antigen (PCNA) immunohistochemistry was used to identify proliferating cells. Clamping the right iliac artery reduced blood flow in the right VP to 0.17 of that in the contralateral lobe. This relative ischemia resulted in a threefold increase in the volume density of apoptotic epithelial cells on the treated side, but left cell proliferation unaffected. Testosterone substitution did not change this pattern. This study suggests that a transient period of relative ischemia may induce apoptosis in the rat ventral prostate. This may be of importance for the understanding of castration-induced prostatic involution.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 37
    ISSN: 1434-0879
    Schlagwort(e): Keywords Ischemia-reperfusion ; Heat shock ; HSP70 ; Kidney ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ischemia-reperfusion injury in the kidney is known to cause induction of the inducible form of the 70 kDa heat shock protein HSP70i (or HSP72). However, knowledge of the expressional regulation of the two coding genes for HSP70i –HSP70-1 gene and HSP70-2 gene – is very limited. We investigated the time course of HSP70-1 and -2 mRNA expression and its relation to cellular ATP levels in the renal cortex after different periods of unilateral warm renal ischemia (10–60 min) and reperfusion (up to 60 min) in 10-week-old male Wistar rats. Immediately after ischemia there was a significant induction of both HSP70i genes. While HSP70-1 expression constantly increased (up to 4-fold) during reperfusion, even to a higher extent with prolongation of ischemia, HSP70-2 mRNA – which was generally expressed at a far lower level than HSP70-1 mRNA – was strongly induced (3-fold) during reperfusion only after brief periods (10 min) of ischemia. Cellular ATP levels rapidly dropped to 5% with ischemia and the pattern of recovery during reperfusion significantly depended on the duration of the ischemic period, thus showing a good relation with the heat shock (protein) gene expression. We conclude that HSP70-2 is the more sensitive gene with a lower activation threshold by mild injury, while the HSP70-1 gene mediates the major response of heat shock protein induction after severe injury.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 38
    ISSN: 1434-0879
    Schlagwort(e): Keywords Testicular neoplasms ; Embryonal cell ; carcinoma ; Apoptosis ; Lymphocytes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Disorders in the regulation of apoptotic cell death may contribute to cancer. Furthermore, lymphocytes are supposed to play a role in counteracting tumorigenesis by inducing apoptosis in different human tumors. In this study, for the first time, tumor cell and lymphocyte apoptosis were investigated systematically in human embryonal cell carcinoma. DNA fragmentation and DNA condensation were measured simultaneously on double-fluorescence-labeled testis tumor sections using immunofluorescence microscopy. Different apoptotic indices (AIs), based either on biochemical (DNA fragmentation) or morphological criteria (DNA condensation) alone or on a combination of both, were determined in different histological regions in and around the tumor. Using morphological criteria alone, 40–75% of all apoptotic cells were not detected. Based on previous observations this finding might be related to subsets of apoptotic cells which induce the process of DNA condensation without activation of processes responsible for DNA fragmentation. Moreover, the AIs of tumor cells and lymphocytes were highest in the tumor region, compared with regions around the tumor and distant from it; these findings are discussed in the context of the Fas/FasL system.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 39
    ISSN: 1432-0533
    Schlagwort(e): Key words c-Jun ; Jun B ; Jun D ; Apoptosis ; Colchicine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The expression of members of the Jun family of transcription factors was examined by immunohistochemistry, Western blotting, in situ hybridization and Northern blotting in the developing and adult rat brain following colchicine administration. Apoptotic cells, as revealed by their typical morphology and positive staining with the method of in situ end-labeling of nuclear DNA fragmentation, were restricted to granule cells of the dentate gyrus and olfactory bulb, and a few cells in the upper layers of the entorhinal cortex in adult rats, whereas widespread apoptosis occurred in developing rats after colchicine administration. No modifications in the expression of Jun D and Jun B, except for a generalized and moderate Jun B expression in glial cells, were observed in colchicine-treated rats. Generalized and strong c-jun mRNA induction and c-Jun/AP-1 (Ab-1) protein expression was observed in the cerebral neocortex, entorhinal and piriform cortices, CA1 and CA3 areas of the hippocampus and granule cell layer of the dentate gyrus in adult treated rats, thus indicating a generalized c-Jun response to colchicine administration. In contrast, c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) immunoreactivity was restricted to apoptotic cells in colchicine-treated adult and developing brains. Western blots of hippocampal homogenates and total brain homogenates in adult and developing rats, respectively, demonstrated a band of 39 kDa for the c-Jun/AP-1 (Ab-1) antibody in control animals, the intensity of which increased in colchicine-treated rats. However, a band of 37 kDa, the intensity of which also increased following colchicine administration, was observed for the c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) antibodies. Selective c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) expression was also observed in apoptotic cells of the SH-SY5Y neuroblastoma line after the addition of colchicine to the culture medium. Taken together, the present in vivo and in vitro results indicate a generalized c-Jun response to colchicine in sensitive cells, whereas the antibodies c-Jun/AP-1 (N) and c-Jun/AP-1 (Ab-2) recognize vulnerable cells dying via apoptosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 97 (1999), S. 192-195 
    ISSN: 1432-0533
    Schlagwort(e): Key words Neuronal vacuolation ; Rottweiler dog ; Bcl-2 ; Bax ; c-Jun ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Neuronal vacuolation, involving the cerebellar roof nuclei, Purkinje cells, selected nuclei of the brain stem, thalamus, Clarke’s column, anterior and posterior horns of the spinal cord, visceral autonomic ganglia and myenteric plexus, as well as axonal degeneration of the white matter of the brain stem, cerebellar pedunculi, dorsolateral columns of the spinal cord and ventral roots of the spinal cord, were observed in two young Rottweiler dogs which were clinically afflicted with hind limb weakness progressing to paraparesia, ataxia, intention tremor, and difficulty in swallowing and barking. The absence of modifications in Bcl-2 and Bax immunoreactivity, a lack of strong c-Jun/AP-1 (N) immunoreactivity in vacuolated cells, and the absence of DNA breaks, as seen with the method of in situ end-labeling of nuclear DNA fragmentation, all suggest that there is no involvement of the apoptotic pathway in vacuolated cells in this new neurodegenerative disorder.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 41
    ISSN: 1432-0533
    Schlagwort(e): Key words Glucocorticosteroids ; Apoptosis ; Guillain-Barré syndrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Lipocortin-1 exerts a potent immunosuppressive effect on pathogenic T cells. In multiple sclerosis and experimental autoimmune encephalomyelitis levels of lipocortins are raised, suggesting their involvement in the recovery from an immunological insult or in neural regeneration. To further understand the role of lipocortins in the peripheral nervous system we have characterized lipocortin-1 levels and cellular distribution of lipocortin-1 immunoreactivity in sciatic nerves of rats with experimental autoimmune neuritis (EAN), a model of human Guillain-Barré syndrome. EAN was induced actively by immunization with bovine peripheral myelin (active EAN) or by adoptive-transfer (AT-EAN) of P2-specific T cells. Cellular infiltrates in serial and semithin cryosections were characterized by immunohistochemistry. In parallel, lipocortin-1 levels in tissue extracts were quantified by a sandwich-ELISA. Only weak lipocortin-1 immunoreactivity was found in nerves of control animals injected with non-pathogenic T cells. The majority of macrophages and lymphocytes in EAN lesions exhibited lipocortin-1 immunoreactivity. Some very heavily stained cells showed a distribution and morphology similar to ED-2-positive macrophages which were abundant during early stages of EAN. Lipocortin-1 expression in T cells and macrophages was proven by immunocytochemical studies in semithin serial sections. In tissue extracts, lipocortin-1 levels increased from 0.24 ± 0.14 μg/mg protein in controls receiving non-pathogenic T cells to a maximum of 0.55 ± 0.1 μg/mg protein in AT-EAN at the peak of disease, and then slowly decreased during clinical recovery but still remained elevated. In dose-response studies in AT-EAN, highest values of lipocortin-1 (0.71 ± 0.23 μg/mg protein) were recorded after transfer of 2 × 107 T cells. Increased levels of lipocortin-1 were also measured in active EAN but occurred during the recovery phase (0.65 ± 0.27 μg/mg protein). By analogy with other immune-mediated disorders, increased lipocortin-1 expression in the inflamed sciatic nerve in EAN may exert immunoregulatory functions in-situ and contribute to the termination of the autoimmune response.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 199 (1999), S. 265-280 
    ISSN: 1432-0568
    Schlagwort(e): Key words Cat ; Rat ; Immunocytochemistry ; NADPH-diaphorase ; Thalamus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  To gain insight into the cellular organisation of the zona incerta, we have examined the chemoarchitectonic properties of this ”uncertain zone”. The brains of Sprague-Dawley rats and common cats were processed for immunocytochemistry or NADPH-diaphorase histochemistry using standard methods. For the immunocytochemistry, antibodies to γ-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD), parvalbumin, calbindin, tyrosine hydroxylase, somatostatin, serotonin and glutamate were used. Two general patterns of distribution in the zona incerta were seen. First, labelled cells were restricted largely to one of the cytoarchitectonically defined sectors of the zona incerta. For instance, GABA, GAD and parvalbumin-immunoreactive cells were found principally within the ventral sector, NADPH-diaphorase and glutamate-immunoreactive cells within the dorsal sector and tyrosine hydroxylase- and somatostatin-immunoreactive cells within the rostral sector. Second, labelled cells were scattered somewhat across all incertal sectors, with no clear region of concentration. This pattern included the calbindin- and serotonin-immunoreactive cell groups. These results indicate that the zona incerta is made up of many neurochemically distinct cell groups, some of which respect the well-defined cytoarchitectonic boundaries of the nucleus, whilst others do not. This rich neurochemical diversity in the zona incerta suggests that this nucleus may have differential effects on the different structures that it projects to.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 43
    ISSN: 1432-0533
    Schlagwort(e): Key words Immediate early gene ; Heat shock protein ; Cerebral ischemia ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The neuroprotective role of the expression of heat shock protein (HSP) and immediate early gene remains unclear. Using immunoelectron microscopy, we examined the ultrastructural integrity of the neurons with expression of c-Fos, c-Jun and HSP70 in gerbils after transient cerebral ischemia and repefusion. Induction of c-Fos and c-Jun was observed in the CA3 region resistant to ischemia, while HSP70 was expressed not only in the CA3 but also in the vulnerable CA1 region. With immunoelectron microscopy, the expression of c-Fos/c-Jun and HSP70 was observed in the neurons which retained neuronal integrity except for mitochondrial swelling and polyribosomal disaggregation. In contrast, the CA1 neurons without immunoreaction for HSP70 showed cytoplasmic vacuoles and parallel stacking of rough endoplasmic reticulum, the features associated with the process of delayed neuronal death. These findings suggested that c-Fos and c-Jun were induced selectively in reversibly damaged neurons, whereas HSP70 was up-regulated even in neurons with irreversible damage, but was more preferentially and intensely expressed in neurons with reversible damage.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 97 (1999), S. 5-12 
    ISSN: 1432-0533
    Schlagwort(e): Key words Creutzfeldt-Jakob disease ; Apoptosis ; Cell death ; Prion protein ; In situ end-labeling of nuclear DNA fragmentation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The method of in situ end-labeling of nuclear DNA fragmentation was used in the study of ten patients (two biopsies, eight autopsies) with sporadic Creutzfeldt-Jakob disease (CJD). All the patients had the typical morphological lesions including neuron loss, spongiform change and astrocytosis. Four of them also showed prion protein (PrP) deposits in the cerebral cortex, and two of them kuru-like plaques in the cerebellum. A few cells with DNA breaks were found in the two biopsy cases; one of them, suffering from a panencephalopathic form of the disease, showed positive nuclei not only in the cerebral cortex but also in the subcortical white matter. Variable numbers of positive nuclei were observed in the gray and white matter in the eight autopsy cases, in which, although the distribution of positive cells roughly correlated with the distribution of neuron loss, no clear relationship was found as regards the distribution and degree of cell labeling and the degree of neuron loss. Furthermore, large numbers of positive cells were concentrated in a particular area, whereas a few cells were seen in a neighboring equally affected area. Positive glial cells in the plexiform layer of the CA1 area of the hippocampus, and in the frontal white matter were frequently encountered. Staining of the cytoplasm in a minority of cells was interpreted as the result of nuclear DNA leakage. None of the stained cells had the typical morphology of apoptosis; most particularly, peripheral chromatin condensation and formation of apoptotic bodies were not seen in any case. PrP deposits did not result in an increase of nuclear DNA breaks either within the area or in adjacent regions. Although positive cells were also observed in autopsy cases of controls which were processed in the same way, positive labeling as a whole was higher in CJD than in age-matched controls. These results show that brain nuclear DNA is vulnerable in CJD, and suggest that increased DNA vulnerability has a role in cell death and neuron loss. Since nuclear shrinkage and positive nuclear staining with the method of in situ end-labeling of nuclear DNA fragmentation are not exclusive to apoptosis, further information is needed to categorize cell death in CJD as apoptosis. Necrosis or other forms of cell death, as well as increased DNA vulnerability to agonal changes of the individuals, and to postmortem delay in the fixation of the tissues, may account for additional positive staining in cases examined at autopsy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 203-214 
    ISSN: 1432-0568
    Schlagwort(e): Key words Extracellular material ; Cell proliferation ; Apoptosis ; Anoikis ; Tenascin ; Laminin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Extracellular material molecules play a key role in the regulation of morphogenesis and differentiation of a large number of organs including the central nervous system. However, the role of the neural basement membrane in the growth of different parts of the neural tube has yet to been delineated. Here, the structural and compositional modifications of the basement membrane (BM) of rhombencephalic tectoria lamina anlage (RTLA) have been examined during the process of RTLA epithelial attenuation. Between stages 10 to 11– the presumptive RTLA epithelium showed a structure, thickness and cell-proliferating capacity similar to those observed in other zones of the rhombencephalic walls. Moreover, the rhombencephalic vesicles were surrounded by a continuous BM that was heterogeneous both ultrastructurally and with regard to ruthenium red, laminin and tenascin distribution. After stage 11, the RTLA epithelium underwent a rapid process of attenuation and change to a stratified flattened epithelium. During this remodelling process, apoptosis and inhibition of both PCNA expression and 3H-thymidine uptake occurred in the RTLA epithelium. The BM of the RTLA underwent a process of degration at the beginning of the remodelling, and apoptosis and cell proliferation inhibition of RTLA epithelium were also observed. The loss of the biochemical signals encoded within the BM could lead to cell shape changes, cell proliferation inhibition and to the anoikis type of cell death. Our findings support the idea that the BM surrounding the neural tube plays a key role in controlling both the structure and growth of the CNS during the early developmental stages.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 239-252 
    ISSN: 1432-0568
    Schlagwort(e): Key words Somite explant culture ; Sonic hedgehog protein ; Myogenic induction ; Primary fiber type diversity ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Primary skeletal muscle fibers first form in the segmented portions of paraxial mesoderm called somites. Although the neural tube and notochord are recognized as crucial in patterning myogenic cell lineages during avian and mammalian somitic myogenesis, the source, identities, and actions of the signals governing this process remain controversial. It has been shown that signals emanating from the ventral neural tube and/or notochord alone or Shh alone serve to activate MyoD expression in somites. However, beyond a role in initiating MyoD expression, little is known about the effects of Shh on primary muscle fiber formation in somites of higher vertebrates. The studies reported here investigate how the ventral neural tube promotes myogenesis and compare the effects of the ventral neural tube with those of purified Shh protein on fiber formation in somites. We show that purified Shh protein mimics actions of the ventral neural tube on somites including initiation of muscle fiber formation, enhancement of numbers of primary muscle fibers, and particularly, the formation of primary fibers that express slow myosin. There is a marked increase in slow myosin expression in fibers in response to Shh as somites mature. The effects of ventral neural tube on fiber formation can be blocked by disrupting the Shh signaling pathway by increasing the activity of somitic cyclic AMP-dependent protein kinase A. Furthermore, it was demonstrated that apoptosis is a dominant fate of somite cells, but not somitic muscle fibers, when cultured in the absence of the neural tube, and that application of Shh protein to somites reduced apoptosis. The block to apoptosis by Shh is a manifestation of the maturity of the somite with a progressive increase in the block as somites are displaced rostrally from somite III forward. We conclude that purified Shh protein in mimicking the effects of the ventral neural tube on segmented mesoderm can exert pleiotropic effects during primary myogenesis, including: control of the proliferative expansion of myogenic progenitor cells, antagonism of cell death pathways within the precursors to muscle fibers, and during the crucial process of primary myogenesis, can exert an effect on diversification of muscle fiber types.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 521-531 
    ISSN: 1432-0568
    Schlagwort(e): Key words Development ; Internal capsule ; Nucleus basalis ; Rat ; Thalamus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  This study defines several features of the early connections of the developmentally transient perireticular thalamic nucleus of rats. The neocortex of developing rats was injected with either DiI, biotinylated dextran, WGA-HRP (wheatgerm agglutinin conjugated-horseradish peroxidase), fluorescent latex beads or cholera toxin subunit B (CTB) and their brains were processed for tracer detection with standard methods. In general, tracer injections into various regions of the developing neocortex revealed no labelled neurones within the perireticular nucleus, although some of these tracers (WGA-HRP, dextran) labelled many of the amoeboid microglial cells that are found within this nucleus. There were, however, many retrogradely labelled neurones in a region adjacent to the perireticular nucleus, within the nucleus basalis of the basal forebrain (medial edge of globus pallidus). Their identity was confirmed as neurones of the nucleus basalis since they were all were similar in morphology and somal size to neurones that were immunoreactive to NGFr (nerve growth factor receptor), an antigen found only among neurones of the nucleus basalis and basal forebrain. Moreover, double labelling experiments revealed that most, if not all, of the cortically labelled neurones were NGFr-immunoreactive also. Thus, in conclusion, our results suggest that the perireticular nucleus does not project to the neocortex; the only neurones in the general vicinity of the perireticular nucleus that have a cortical projection form part of the nucleus basalis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 533-540 
    ISSN: 1432-0568
    Schlagwort(e): Key words Coronary vasculogenesis ; Angiogenesis ; Coronary artery ; Development ; Rat ; Embryonic heart
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The aim of this work was to address spatiotemporal and morphologic patterns of coronary artery development in rats, based on immunohistochemical and ultrastructural studies of hearts at different stages of prenatal development. Griffonia simplicifolia I lectin and α-smooth muscle antibody were used to demonstrate endothelial cells and/or their precursors and smooth muscle cells, respectively. Ultrastructural examination was performed on ED14–16 hearts to study the morphology of the developing coronary arteries in different regions of the truncus arteriosus and adjacent myocardium. On ED14 endothelial-like cells present within the mesenchyme surrounding the outflow tract penetrated the aortic wall and the truncoconal proximal myocardium. On ED15 these penetrating cells formed vascular clusters, which were the first signs of presumptive vascular channels. Development of the coronary artery proceeded by coalescence of discontinous vascular clusters, formation of the lumen (vascular channels) and establishing a connection of the proximal part with the aorta. The second layer of cells around vascular channels (embryonic media) consisted of mesenchymal cells that were attracted to the immature vessel and were first seen on ED15. At this time no lumenized connection of the coronary artery with the aorta has been seen. After the lumenized connection of the coronary artery with the aorta had been established perivascular cells of the media started to differentiate into vascular smooth muscle, as was shown by α-smooth muscle actin-staining. Further development and differentiation of the media and adventitia proceeded distally (towards the apex).
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    ISSN: 1432-0568
    Schlagwort(e): Key words Morphogenesis ; Histochemistry ; Lectins ; Carbohydrates ; Salivary glands ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The developmental expression of salivary glycoconjugates was investigated in the rat submandibular and sublingual glands by conventional and lectin histochemistry. By the time of the first differentiation of secretory structures, in spite of similar morphological features, a different histochemical reactivity was detected, accounting for a relevant content of neutral glycoconjugates in the submandibular gland and the occurrence of both neutral and acidic glycoconjugates in the sublingual one. The use of lectins allowed the main changes of secretory components to be noted around gestational day 18. DBA and WGA lectins seemed to act as pre- and post-natal development markers while Con A lectin was indicative of post-natal differentiation. Taken together, data from lectin histochemistry indicated the transitional occurrence of glycoconjugates, probably involved in temporally restricted functions, as well as the co-existence of different secretory components that might also reflect maturational changes of single products.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 50
    ISSN: 1432-0533
    Schlagwort(e): Key words Parkinson’s disease ; Apoptosis ; Bcl-2 ; Bax ; Bcl-x
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We studied the substantia nigra of three Parkinson’s disease (PD) patients and three age-matched individuals by in situ DNA-end labeling (ISEL) and immunohistochemistry for the apoptosis regulating proteins Bcl-2, Bax and Bcl-x on 50 consecutive sections per patient. No melanin-containing cell was identified with typical apoptotic changes in either patient or control substantia nigra. With prolonged reaction-time the terminal transferase-mediated DNA-end labeling revealed a signal in 2.0 ± 1.2% melanin-containing cells in PD compared to 1.3 ± 1.1% in control. This difference did nor reach statistical significance and no condensation or margination of the chromatin was evident. No significant changes of any of the apoptosis regulating proteins were apparent in PD substantia nigra. These findings do not support the hypothesis that apoptosis plays a central role in the pathogenesis of PD.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 51
    ISSN: 1432-0533
    Schlagwort(e): Key words Clomethiazole ; Rat ; Spinal cord-injury ; Neuroprotection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Clomethiazole (CMZ) has a neuroprotective effect in experimental focal and global forebrain ischemia. This neuroprotective effect may depend on its ability to enhance GABA receptor activity. We have studied the effect of pretreatment with CMZ on motor function recovery and nerve cell damage after spinal cord injury (SCI). Rats were randomized and 30 min before SCI they received a single intraperitoneal dose of CMZ (150 mg/kg) or saline. The spinal cord was injured with a 50 g (4.5 g/mm2) load, applied over the exposed dura, through a curved rectangular plate (2.2 × 5.0 mm) for 5 min at T8–9. The animals became paraplegic 1 day after injury. The rats were evaluated for recovery of hind limb motor function. All animals recovered to some extent over the observation period of 12 weeks. However, hind limb motor function was significantly better in the animals pretreated with CMZ. At 12 weeks the rats were killed and perfused/fixed for morphological investigations. Microtubule-associated protein 2 (MAP2) immunostaining was used to stain neurons and dendrites and Luxol-fast blue to stain myelinated tracts of the white matter. The injured segment of the spinal cord showed severe atrophy, distortion, cavitation and necrosis of grey and white matter. Compared to uninjured controls the transverse sectional area was reduced to 32.7 ± 4% in untreated animals but only to 38.5% ± 4.1 in CMZ-treated animals. MAP2 staining showed that, compared to uninjured controls, grey matter was reduced to 7.4 ± 2.7% in saline-treated injured animals and to 22.7 ± 5.4% in CMZ-treated rats. Our results thus show that in this model CMZ improves hind limb motor function and attenuates the morphological damage to the spinal cord.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 97 (1999), S. 279-287 
    ISSN: 1432-0533
    Schlagwort(e): Key words Canine distemper virus ; Oligodendrocytes ; Apoptosis ; Necrosis ; Demyelination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Canine distemper virus (CDV) causes a multifocal demyelinating disease in dogs. It was previously shown that the initial demyelinating lesions are directly virus induced since a correlation between the occurrence of demyelination and CDV replication in white matter cells was observed. During the course of infection oligodendrocytes undergo distinct morphological alterations, partly due to a restricted CDV infection of these cells, and eventually disappear from the lesions. This phenomenon has been described in vivo as well as in vitro. However, the reason for the morphological alterations and the following oligodendroglial depletion remained unclear. Since virus infection can induce cell death, it was investigated whether apoptosis or necrosis plays a role in the pathogenesis of demyelination in canine distemper. In brain tissue sections from dogs with acute distemper apoptotic cells were not detected within the demyelinating lesions using morphological and biochemical cell death criteria. In chronic distemper, apoptotic cells – presumably inflammatory cells – were seen within the perivascular cuffs. These in vivo findings were correlated to the in vitro situation using CDV-infected primary dog brain cell cultures as well as Vero cells. Infection with culture-adapted CDV lead to massive necrosis but not to apoptosis. After infection with virulent CDV neither apoptosis nor necrosis was a predominant feature in either culture system. These findings suggest that virus-induced demyelination in canine distemper is not the direct consequence of apoptosis or necrosis. It is speculated that another mechanism must be responsible for the observed morphological alterations of oligodendrocytes, ultimately leading to demyelination.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 53
    ISSN: 1432-0568
    Schlagwort(e): Key words Brain ; Cortical parcellation ; Development ; Proteoglycans ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Nitric oxide (NO) regulates several functions both in the developing and the adult central nervous systems (CNS). During development, NO is assumed to contribute to the histogenetic differentiation of the CNS especially through the modulation of programmed neuronal death. The embryonal and postnatal changes in the distribution of the cortical NO producing system were studied in Balb/c mice using immunocytochemistry for nitric oxide synthase-I (NOS-I) and NADPH-diaphorase (NADPH-d) enzyme histochemistry. NOS-I reactive neurons (RN) appeared first at embryonic day 14 (E14) in the spinal cord in the vicinity of the central canal, and later, at E16–18, in the thalamus and striatum. The first cortical region to present NOS-I reactivity was the parietal cortex, which happened at E18–20. After E20 the number of NOS-I RN increased in every cortical area, plateauing at postnatal day 4 (P4). In parietal regions, however, the highest density of NOS-I RN was observed already at P1. The neuronal packing density (PD) of NOS-I RN declined until adulthood, interrupted by a transient increase in some cortical areas at the onset of puberty. The heterochronous appearance of NOS-I during pre- and postnatal development of different brain regions and the sequence of up- and downregulation of expression until adult stages points to an important role of NO in brain development and functional differentiation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 200 (1999), S. 413-417 
    ISSN: 1432-0568
    Schlagwort(e): Key words Receptor cell ; Axon ; Vomeronasal organ ; Regeneration ; Rat ; HRP-WGA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Chemosensory neurons in the vomeronasal epithelium (vomeronasal neurons) regenerate following experimentally induced degeneration. Transection of the vomeronasal nerves leads to retrograde degeneration of vomeronasal neurons followed by replacement of the cell population. The projection of the axons of regenerated vomeronasal neurons was examined by horseradish peroxidase(HRP) histochemistry and electron microscopy. HRP-wheat germ agglutinin (WGA) was placed on the surface of the vomeronasal organ of the rat. Dense distribution of HRP-labeled fibers was observed in the vomeronasal nerve and glomerular layers in the accessory olfactory bulb (AOB) of the intact rat. At one week after transection, HRP-labeled fibers were not found in the AOB, and no labeled fibers could be observed on the medial surface of the olfactory bulb where the vomeronasal nerve traversed. Three weeks after transection, labeled fiber bundles were observed on the medial surface of the olfactory bulb in all animals. No labeled fibers were detected in the AOB. From 12 to 32 weeks after transection, projection of HRP-labeled fibers was identified in the AOB in 8 out of 26 rats (the incidence of projection was 30%). But the number of projection fibers on the operated side was much smaller than on the control side. Electron microscopy confirmed that the HRP-labeled terminals make synaptic contacts with neurons in the AOB.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 55
    ISSN: 1432-0568
    Schlagwort(e): Key words Synaptogenesis ; Primate ; Spinal cord ; Apoptosis ; Neuropeptides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Development of glomerular synapses in the superficial dorsal horn has been studied in the embryonic macaque spinal cord using light and electron microscopic techniques including Golgi impregnation, 3H-thymidine radioautography and pre-embedding immunohistochemistry of substance P (SP), calcitonin gene related peptide (CGRP), calbindin D-28 K (CB) and parvalbumin (PV). The study revealed that substantia gelatinosa cells of the primate dorsal horn are generated last, but unlike in rodents, synaptogenesis in this region starts at early embryonic (E) stages of the 165-day long gestation. Already by E30, both Type 1 (light) and 2 (dark) dorsal root axons and their growth cones are identifiable within the oval bundle of His, before they form synaptic contact with their final target cells. Subsequently they invade the dorsal horn and enter the bisecting interfaces formed by orderly programmed cell death. Each type of scalloped (sinusoid) central primary afferent terminal (i.e. DSA, RSV and LDCV) have well defined pre- and post-synaptic specializations already by E40. Among the neuropeptides studied, SP appears first at E67 and CGRP at E70 in the lateral position but within a few days both of them are spread to the entire superficial dorsal horn. Both SP and CGRP are present in the thin dorsal root axons and their growth cones, giving rise to scalloped and simple axon terminals. PV is transiently present in the entire length of the thick dorsal root afferents before becoming concentrated in the synaptic boutons. CB is displayed mainly in neurons of the lamina I and III. Dendrites of CB-immunoreactive cells establish synaptic connection with each type of dorsal root afferents, including glomerular synaptic complexes. These data reveal that the superficial dorsal horn in the primate spinal cord develops its characteristic synaptic complexes much earlier in gestation than in any other mammalian species studied. Furthermore, characteristic cytological features of the prospective glomerular complex emerge before establishment of the final synaptic contacts.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 291 (1999), S. 212-216 
    ISSN: 1432-069X
    Schlagwort(e): Key words UV irradiation ; Solar-simulated irradiation ; Apoptosis ; bcl-2 ; bax
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Recently, the proto-oncogenes bcl-2 and bax have emerged as important regulators of the apoptotic form of cell death. We examined UV irradiation-elicited apoptosis and regulation of bcl-2 and bax expression both in vivo in human skin and in vitro in HeLa cells. Using flow cytometric analysis, HeLa cells were found to undergo apoptosis at the 12-h time-point after exposure to UVB irradiation (100 mJ/cm2). The expression of bcl-2 mRNA was found to decrease after a single dose of UVB radiation (doses 10–200 mJ/ cm2). In contrast, the expression of bax mRNA was not significantly changed. When human skin was irradiated with a single dose of solar-simulated radiation (40 mJ/cm2), Bcl-2-positive cells were significantly reduced in the epidermis at the 3- and 6-h time-points. Our results suggest that UV irradiation downregulates bcl-2 expression both in vitro at the mRNA level and in vivo at the protein level, and that downregulation of bcl-2 constitutes a mechanism of potential importance in UV-induced apoptosis in human epidermis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    ISSN: 1432-069X
    Schlagwort(e): Key words TUNEL ; Apoptosis ; Trichilemmal ; keratinization ; Epidermal appendages
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 291 (1999), S. 303-305 
    ISSN: 1432-069X
    Schlagwort(e): Key words Langerhans cells ; Sunburn cells ; UV ; erythema ; Apoptosis ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 59
    ISSN: 1432-069X
    Schlagwort(e): Key words Keratinocyte ; UVB ; Apoptosis ; Calcium ; p53
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Normal human keratinocytes are stimulated to proliferate in serum-free medium containing subphysiological concentrations of calcium (0.09 mM, low calcium). In this study, we examined the effect of increased levels of extracellular calcium (2.0 mM, normal calcium) on UVB-induced apoptosis. Apoptosis was assessed by changes in cellular morphology, annexind V-FITC flow cytometry, and the formation of internucleosomal DNA ladders. High doses of UVB induced keratinocytes grown in low calcium medium to undergo apoptosis. In contrast, keratinocytes grown for 72 h in normal calcium medium were completely resistant to UVB-induced apoptosis. No apoptosis was observed even at UVB doses as high as 1200 J/m2. However, despite the lack of UVB-induced cell death, keratinocytes grown in normal calcium medium lost the ability to proliferate following high levels of UVB irradiation. High doses of UVB also increased the expression of the differentiation-specific proteins involucrin and cytokeratin 10 in a dose-dependent manner. In addition, growth in normal calcium medium lowered the UVB-induced stimulation of the p53 protein and altered the normal subcellular localization pattern of p53. UVB irradiation of human keratinocytes grown in normal calcium medium may be inducing further cell differentiation in the absence of overt cell death.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 60
    ISSN: 1432-0584
    Schlagwort(e): Key words IL-6 variants ; Cell cycle ; Apoptosis ; Multiple myeloma ; Cell line
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Interleukin-6 (IL-6) serum levels and the proliferative activity of bone marrow plasma cells have been described as important prognostic factors for survival duration in multiple myeloma (MM) patients. Since growth of neoplastic plasma cells is frequently promoted by IL-6, inhibition of its activity has been considered for the management of MM patients. With a similar rationale, IL-6 variants characterized by wild-type or increased affinity for the ligand-specific IL-6 α receptor chain and reduced ability to bind and/or dimerize the gp 130 chain have recently been generated. In the present study, the antiproliferative effects of the variants Sant1, Sant5, and Sant7, characterized by increasing antagonistic activity, were investigated by means of a detailed cell kinetic and apoptotic analysis of the IL-6-dependent MM XG-1 cell line. A significant reduction in the mean percent of XG-1 cells in active S-phase (DNA/bromodeoxyuridine incorporation) from 41% to 28.1% (p=0.04), 25.8% (p=0.04), and 15.3% (p=0.02), respectively, was observed using Sant1, Sant5, and Sant7. These effects were confirmed using the acridine-orange (AO) flow-cytometric technique, which showed a similar reduction of S-phase (34.2% of baseline value) in the presence of Sant1, Sant5, and Sant7, as well as a significant G1b arrest (from 44.5% to 47.6%, 48%, and 64.9%). Furthermore, IL-6 variants were capable of down-regulating the G1 cell cycle regulatory protein cyclin D1 expression. Cell cycle effects were coupled with a significant increase of apoptosis, measured by the AO and the terminal deoxynucleotidyl transferase assays, from 12.9% (control culture with IL-6) to 21.2% (Sant1), 29.1% (Sant5), and 23.5% (Sant7). These results were comparable to those obtained by depriving XG-1 of recombinant IL-6. Our study documents the antiproliferative activity exerted by IL-6 mutants on the XG-1 cell line, thus supporting the investigation of these molecules on primary MM cells.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 61
    ISSN: 1432-0584
    Schlagwort(e): Key words Idiopathic myelofibrosis ; PCNA labeling ; Apoptosis ; Dynamic disease features ; Prognosis ; Proportion of life loss ; Bone marrow
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A retrospective study of 120 patients with the clinically and histologically established diagnosis of idiopathic (primary) myelofibrosis (IMF) was performed to determine prognostic factors of predictive value, including parameters characterizing the dynamics of hematopoietic cell kinetics. In contrast to previous studies, our cohort comprised the full spectrum of the disease, from initial prefibrotic to advanced osteosclerotic stages. The in situ end-labeling (ISEL) technique was used to demonstrate apoptosis, in order to determine dynamic parameters of predictive value. Cell proliferation was evaluated by employing the monoclonal antibody PC10 directed against proliferating cell nuclear antigen (PCNA). Proliferative activity (PCNA index) and frequency of apoptosis showed significant differences between early and advanced fibrosclerotic stages of disease. Decrease in proliferation indicated a significantly shorter survival, whereas a higher frequency of apoptotic cells was associated with a better prognosis. It may be speculated that a normal or enhanced proliferation rate expressed by PCNA positivity (late G1- and S-phase of the cell cycle) that is accompanied by a higher incidence of apoptosis reflects the regenerative (turnover) capacity of hematopoiesis. This may apply especially to early hypercellular stages without relevant myelofibrosis. In consideration of a recently published multivariate risk model, a simplified synthesis score for stratification of a patient's prognosis was constructed. Age, degree of anemia, leukocytes, and platelet count were regarded as the most important parameters. A substantial improvement of prognostic efficiency was further achieved by including PCNA index and frequency of apoptosis. Our results are in keeping with the assumption that generalization, indicated by myeloid metaplasia, has a prodigious impact on prognosis in IMF. Furthermore, in this context dynamic features such as proliferative activity and frequency of apoptosis exert an additional predictive value.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 62
    ISSN: 1423-0127
    Schlagwort(e): TNFα ; Fas ; FasL ; Apoptosis ; Cytokine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The CD3+/TCRαβ+ T-cell-mediated hepatic inflammation induced byPropionibacterium acnes could be divided into an acute and a chronic phase. The acute phase occurred within 72 h after injection and displayed hepatic apoptosis. Anti-TNFα antibody inhibited both theP. acnes-induced hepatic apoptosis and lymphocyte infiltration seen in this phase, indicating the involvement of this cytokine. Thereafter, a chronic phase was manifested from days 7 to 14 after injection. It was characterized as granulomatous inflammation admixed with apoptosis of infiltrating lymphocytes and some hepatocytes. Immunohistochemical staining showed that the infiltrating lymphocytes displayed TNFα, TNF type I receptor and a variety of cytokines including IL-1β, IL-4, IL-6, IL-10, IFNγ or IL-12. Interestingly, in naive mice, the arteries in the liver constitutively expressed IFNγ. Its expression appeared to be substantially increased at 48 h, decreased at 72 h, and increased again on day 14 afterP. acnes injection. Furthermore, Fas or FasL was only detected on the lymphocytes within the granuloma. We conclude thatP. acnes can induce a TNFα-mediated acute hepatic apoptosis which subsequently progress to a T-cell-mediated granulomatous hepatitis with increased expression of multiple cytokines and Fas/FasL.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Journal of biomedical science 6 (1999), S. 433-438 
    ISSN: 1423-0127
    Schlagwort(e): AIDS dementia complex ; Antioxidants ; Apoptosis ; Cerebral atrophy ; gp120 ; HIV-1 protease ; Human neuroblastoma cell ; Neuroprotection ; Protease inhibitor (KNI-272)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract A significant number of adult male patients with acquired immunodeficiency syndrome develop cerebral atrophy and progressive brain disorders such as dementia complex and neuropsychiatric problems. Upon entering the brain via activated macrophages or microglias, the human immunodeficiency type 1 virus (HIV-1) may produce cytotoxic factors such as HIV-1 envelope protein (gp 120) and protease. Owing to significant proteolysis of nonviral proteins, the protease derived from HIV-1 may be detrimental to brain cells and neurons. Our results revealed that HIV-1 protease, at nanomolar concentrations, was as potent as gp 120 in causing neurotoxicity in human neuroblastoma neurotypic SH-SY5Y cells. As shown by the Oncor ApopTag staining procedure, HIV-1 protease significantly increased the number of apoptotic cells over the serum-free controls. Moreover, HIV-1 protease-induced neurotoxicity was blocked by a selective protease inhibitor, kynostatin (KNI-272). Antioxidants such as 17β-estradiol, melatonin, andS-nitrosoglutathione also prevented protease-induced neurotoxicity. These findings indicate that oxidative proteolysis may mediate HIV-1 protease-induced apoptosis and the degeneration of neurons and other brain cells. Centrally active protease inhibitors and antioxidants may play an important role in preventing cerebral atrophy and associated dementia complex caused by HIV-1.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Hematology and cell therapy 41 (1999), S. 153-161 
    ISSN: 1279-8509
    Schlagwort(e): p53 ; Apoptosis ; PKC ; g-irradiation ; Transcription
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Several mutations prevent the expression of p53 in the human lymphoblastoid T cell line Jurkat. Restoration of p53 in Jurkat cells had no effect on the cell growth but markedly increased the amount of apoptosis induced by g-irradiation. Inhibition of RNA synthesis using 5,6-dichlorobenimidizole riboside had little effect on apoptosis induced by irradiation in the presence of p53 and did not affect the p53-independent apoptotic pathway. Expression of p53 also had no effect on the expression levels of proteins such as Fas, GADD45, Bax, Bcl-2, Bcl-xL or p53 induced proteins (PIGS) in resting cells or after irradiation. Activation of protein kinase C by phorbol 12-myristate 13-acetate produced an almost complete inhibition of p53-independent apoptosis following irradiation, whereas no significant effect was observed on the rate of p53-induced apoptosis. Although phorbol 12-myristate 13-acetate strongly induced p21 and stabilised p53 in the resting transfected Jurkat cells, neither apoptosis nor cell arrest was observed. In summary, this work shows that p53 enhances the radiosensitivity of Jurkat cells through an apoptotic process that is triggered by irradiation and is largely independent of RNA synthesis and protein kinase C activation. Apoptosis in p53- negative Jurkat cells is strongly inhibited by PMA indicating that the pathway triggered by p53 may be distinct from apoptotic pathways used in its absence.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 65
    ISSN: 1423-0127
    Schlagwort(e): Autoimmunity ; Apoptosis ; IL-2 ; FasL ; Tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Studies of several gene knockout mice suggest an interesting association of a moderate T cell response with systemic autoimmune diseases. In addition, CD95 ligand (FasL) expression in some strains of these mice is impaired. Because FasL is critically involved in regulating peripheral tolerance, there may be a link between autoimmune diseases and a moderate T cell response that cannot activate the FasL gene. Here, we propose that there are two thresholds of T cell activation. When moderately stimulated, T cells can be activated to the low (1st) threshold, which permits the induction of CD40L, IL-2, IL-4, and other components that help the immune response. The high (2nd) activation threshold can only be achieved by a strong and concurrent stimulation through TCR and IL-2R. Once the high threshold is reached, FasL is produced to induce apoptosis of the activated T and B cells. In the absence of the FasL-mediated downregulation, the activated B cells become efficient antigen-presenting cells for self-antigens and excellent responders for T cell help. Such an exacerbating condition, induced by recurrent and moderate activation, favors the development of autoreactive T cells and autoantibody production. Evidence supporting this hypothesis and some predictions that can be tested are described.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 208 (1999), S. 183-188 
    ISSN: 1431-4630
    Schlagwort(e): Key words Sulphadimidine ; Fermented sausage ; Carbon-14-labelling ; Rat ; Bound residues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  Sulphadimidine (SDM), a drug frequently administered to pigs, is partially converted into other compounds by processing meat to produce raw, fermented sausage. With the aid of 14C-labelled SDM, evidence was obtained that part of the radioactive matter was covalently bound to the matrix. Part of these bound residues could be released in vitro by 4 M HCl at 21  °C or by 0.024 M HCl at 37  °C. Female rats were also able to release bound SDM residues and to excrete these in their urine, in amounts approaching those obtained by treatment with 4 M HCl. Both the parent compound and its main metabolite, N 4-acetyl-SDM, were observed in the urine of rats.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 67
    ISSN: 1423-0127
    Schlagwort(e): Glioma ; Apoptosis ; Vandate ; Akt ; PKB
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The dual signal hypothesis of apoptosis holds that a common signal can activate both apoptotic and proliferative pathways. The fate of a cell is dependent on which of these two pathways predominates. In the MAPK family of kinases, ERK and JNK have been proposed to mediate apoptosis whereas the PI3K-stimulated kinase, Akt/PKB, has been shown to inhibit apoptosis. The object of this study was to determine the role of these kinases in a glioma model of apoptosis. We have previously shown that K252a induces apoptosis and inhibits kinase activity. In this study we confirm these results and shown that the protein tyrosine phosphatase inhibitor sodium vanadate activates ERK, JNK and Akt/PKB, but does not stimulate proliferation. Vanadate did protect T98G cells from K252a-induced apoptosis, an effect that was abolished by addition of the PI3K inhibitor wortmannin. This suggests that PI3K and Akt/PKB may be responsible for mediating vanadate's protective effect on glioma cells. We conclude that the intracellular balance between protein phosphorylation pathways is a critical determinant of both cell proliferation and cell death.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Cancer chemotherapy and pharmacology 44 (1999), S. 81-87 
    ISSN: 1432-0843
    Schlagwort(e): Key words Cyclin-dependent kinase ; Cytotoxicity ; Apoptosis ; Multidrug resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: To determine the in vitro effects of flavopiridol on bladder cancer cell lines, immortalized urothelial cell lines, and normal urothelial cells well characterized for defects in p53, pRb, and p16. Methods: Growth inhibition was assessed via an MTT assay and apoptosis via DAPI nuclear staining. Cell cycle analysis was performed via propidium iodide staining and fluorescent activated cell sorting (FACS). Multidrug-resistant cells were generated by continuous exposure to doxorubicin. Results: Growth inhibition was not correlated with inactivation of p53, pRb, or p16. All cells experienced G2/M arrest within 24 h of flavopiridol exposure. Modest apoptosis was observed but required 72 h of continuous drug exposure to become evident. There was no obvious synergistic or antagonistic toxicity when flavopiridol was combined with radiotherapy or cisplatin dosed at the IC50 despite the observation that radiotherapy and flavopiridol led to more profound G2/M arrest than either agent alone. Doxorubicin-resistant cells, demonstrated to overexpress the MDR1 multidrug-resistance protein were equally as sensitive to flavopiridol as the parental cells. Conclusions: Flavopiridol is a novel cell cycle inhibitor that may be a useful agent in bladder cancers with tumor suppressor gene alterations and/or multidrug resistance.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 69
    ISSN: 1432-0843
    Schlagwort(e): Key words Dolastatin ; Lung cancer ; Apoptosis ; Xenografts ; Experimental therapeutics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: Dolastatin 10 is a natural cytotoxic peptide which acts through the inhibition of microtubule assembly. Studies have suggested that such agents can induce apoptosis in association with bcl-2 phosphorylation. Since bcl-2 overexpression is common in small-cell lung cancer (SCLC), we evaluated the activity of dolastatin 10 in SCLC cell lines and xenografts. Methods: In vitro growth inhibition was evaluated with a standardized MTT assay and apoptosis with fluorescent microscopy and a TUNEL assay. Immunoblot analysis and phosphatase digestion were used to determine bcl-2 modification. In vivo activity was evaluated in subcutaneous and metastatic SCLC xenograft models in SCID mice. Results: Dolastatin 10 had growth inhibitory activity against four SCLC cell lines (NCI-H69, -H82, -H446, -H510) with IC50 values ranging from 0.032 to 0.184 nM. All four cell lines exhibited evidence of apoptosis after 48 h of exposure to 1.3 nM dolastatin 10. Immunoblot analysis revealed that 1.3 nM dolastatin 10 altered the electrophoretic mobility of bcl-2 in NCI-H69 and -H510 cells within 16 h of treatment. Incubation of protein extract from dolastatin 10-treated NCI-H69 and -H510 cells with calcineurin resulted in the disappearance of the altered mobility species, suggesting dolastatin 10-induced bcl-2 phosphorylation. In in vivo studies, 450 μg/kg of dolastatin 10 IV × 2 given after intravenous injection of NCI-H446 cells completely inhibited tumor formation. In established subcutaneous NCI-H446 xenografts, 450 μg/kg of dolastatin 10 IV induced apoptosis in the majority of tumor cells within 96 h, resulting in a log10 cell kill of 5.2 and an increase in median survival from 42 to 91 days. Conclusions: These findings suggest that dolastatin 10 has potent activity against SCLC and that the modulation of apoptotic pathways deserves further evaluation as an anticancer strategy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Cancer chemotherapy and pharmacology 44 (1999), S. 444-452 
    ISSN: 1432-0843
    Schlagwort(e): Key words Baccatin III ; Paclitaxel ; Apoptosis ; Mitotic arrest ; bcl-2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: Paclitaxel has been demonstrated to possess significant cell-killing activity in a variety of tumor cells by induction of apoptosis, but the mechanism by which paclitaxel leads to cell death and its relationship with mitotic arrest is not entirely clear. In this study, baccatin III, a synthetic precursor of paclitaxel, was used to analyze whether paclitaxel-induced apoptosis can be a separate event from microtubule bundling and G2/M arrest. Methods: Several different methods including DNA fragmentation, flow cytometric analyses, TdT-mediated dUTP nick end labeling (TUNEL) and time-lapse video microscopy were used to analyze apoptotic cell death induced by baccatin III and its possible correlation with cell cycle distribution. Results: Our results demonstrated that baccatin III could also cause apoptotic cell death in both BCap37 (a human breast cancer cell line) and KB cells (derived from human epidermoid carcinoma), but had less effect on microtubule bundling and G2/M arrest. Furthermore, we demonstrated that most apoptotic events induced by baccatin III were not coupled with G2/M arrest. Instead, these apoptotic events occurred predominantly in the cells in other phases of the cell cycle. Conclusion: Baccatin III, which contains the core taxane ring, is the fundamental piece of paclitaxel structure. The finding of baccatin III-induced apoptosis independent of cell cycle arrest, on the one hand, implies that the core taxane ring may play a critical role in inducing cell death and, on the other hand, suggests that paclitaxel might induce apoptosis from other phases of the cell cycle by a similar mechanism.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 71
    ISSN: 1432-0851
    Schlagwort(e): Key words Immunotherapy ; MK-1 antigen ; Chimeric antibody ; ADCC ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Mouse monoclonal antibody FU-MK-1, raised against a human gastric adenocarcinoma, recognizes a glycoprotein antigen (termed MK-1 antigen) present on most carcinomas and seems to be valuable in immunodiagnosis and immunotherapy of various cancers. In a recent study, we constructed a mouse/human chimeric antibody, designated Ch FU-MK-1, by fusing the FU-MK-1 VH and Vκ genes to the human Cγ1 and Cκ genes, respectively. In the present study, we tested combination immunotherapy of Ch FU-MK-1 with human lymphokine-activated killer (LAK) cells in vitro and in mice with severe combined immunodeficiency (SCID) bearing human MK-1-expressing tumors. In in vitro experiments, Ch FU-MK-1 effectively mediated antibody-dependent cell-mediated cytotoxicity (ADCC) against MK-1-expressing MKN-74 cells, which was completely blocked by an anti-FcR antibody. Since the apoptotic pathway as well as the necrotic pathway have been shown to be utilized in various cytotoxic effector mechanisms, we investigated the role of apoptosis in ADCC mediated by LAK cells and Ch FU-MK-1 against MKN-74 cells. The implication of the apoptosis during ADCC was demonstrated by means of both a terminal-deoxynucleotidyltransferase-mediated dUTP-biotin nick-end-labeling assay and a propidium iodide staining method. In vivo antitumor activity of combination treatment with LAK cells and Ch FU-MK-1 was estimated using SCID mice inoculated s.c. with MKN-74 cells. The i.v. administration of LAK cells and i.p. administration of Ch FU-MK-1 and interleukin-2 (IL-2) produced a marked growth inhibition of MKN-74 tumors in SCID mice. When the actual tumor weights were measured 16 days after initiation of treatment, more than 70% reduction was observed in the group receiving LAK cells plus Ch FU-MK-1 plus IL-2 as compared to the control untreated group. Together these results suggest that Ch FU-MK-1 may serve as a potentially useful immunotherapeutic reagent for human MK-1-expressing tumors.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 72
    ISSN: 1432-1211
    Schlagwort(e): Key words Class II MHC sequence ; Rat ; Cloning ; RT-PCR ; Polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 73
    Digitale Medien
    Digitale Medien
    Springer
    International journal of colorectal disease 14 (1999), S. 201-211 
    ISSN: 1432-1262
    Schlagwort(e): Key words Inflammatory bowel disease ; TNBS rat model ; Resistant starch ; Absorption of short-chain fatty acids ; Butyrate functions ; Proliferation ; Apoptosis ; Matrix proteins ; Intestinal microflora
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  These studies were performed to test the benefit of resistant starch on ulcerative colitis via prebiotic and butyrate effects. Butyrate, propionate, and acetate are produced in the colon of mammals as a result of microbial fermentation of resistant starch and other dietary fibers. Butyrate plays an important role in the colonic mucosal growth and epithelial proliferation. A reduction in the colonic butyrate level induces chronic mucosal atrophy. Short-chain fatty acid enemas increase mucosal generation, crypt length, and DNA content of the colonocytes. They also ameliorate symptoms of ulcerative colitis in human patients and rats injected with trinitrobenzene sulfonic acid (TNBS). Butyrate, and also to a lesser degree propionate, are substrates for the aerobic energy metabolism, and trophic factors of the colonocytes. Adverse butyrate effects occur in normal and neoplastic colonic cells. In normal cells, butyrate induces proliferation at the crypt base, while inhibiting proliferation at the crypt surface. In neoplastic cells, butyrate inhibits DNA synthesis and arrests cell growth in the G1 phase of the cell cycle. The improvement of the TNBS-induced colonic inflammation occurred earlier in the resistant starch (RS)-fed rats than in the RS-free group. This benefit coincided with activation of colonic epithelial cell proliferation and the subsequent restoration of apoptosis. The noncollagenous basement membrane protein laminin was regenerated initially in the RS-fed group, demonstrating what could be a considered lower damage to the intestinal barrier function. The calculation of intestinal short-chain fatty acid absorption confirmed this conclusion. The uptake of short-chain fatty acids in the colon is strongly inhibited in the RS-free group, but only slightly reduced in the animals fed with RS. Additionally, RS enhanced the growth of intestinal bacteria assumed to promote health. Further studies involving patients suffering from ulcerative colitis are necessary to determine the importance of RS in the therapy of a number of intestinal diseases and the maintenance of health.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 74
    ISSN: 1432-1106
    Schlagwort(e): Key words Coherence ; Entorhinal cortex ; Cortex ; Hippocampus ; Amygdala ; 192 IgG-saporin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Changes in brain electrical activity in response to cholinergic agonists, antagonists, or excitotoxic lesions of the basal forebrain may not be reflective entirely of changes in cholinergic tone, in so far as these interventions also involve noncholinergic neurons. We examined electrocortical activity in rats following bilateral intracerebroventricular administration of 192 IgG-saporin (1.8 µg/ventricle), a selective cholinergic immunotoxin directed to the low-affinity nerve growth factor receptor p75. The immunotoxin resulted in extensive loss of choline acetyl transferase (ChAT) activity in neocortex (80%–84%) and hippocampus (93%), with relative sparing of entorhinal-piriform cortex (42%) and amygdala (28%). Electrocortical activity demonstrated modest increases in 1- to 4-Hz power, decreases in 20- to 44-Hz power, and decreases in 4- to 8-Hz intra- and interhemispheric coherence. Rhythmic slow activity (RSA) occurred robustly in toxin-treated animals during voluntary movement and in response to physostigmine, with no significant differences seen in power and peak frequency in comparison with controls. Physostigmine significantly increased intrahemispheric coherence in lesioned and intact animals, with minor increases seen in interhemispheric coherence. Our study suggests that: (1) electrocortical changes in response to selective cholinergic deafferentation are more modest than those previously reported following excitotoxic lesions; (2) changes in cholinergic tone affect primarily brain electrical transmission within, in contrast to between hemispheres; and (3) a substantial cholinergic reserve remains following administration of 192 IgG-saporin, despite dramatic losses of ChAT in cortex and hippocampus. Persistence of a cholinergically modulated RSA suggests that such activity may be mediated through cholinergic neurons which, because they lack the p75 receptor, remain unaffected by the immunotoxin.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 75
    ISSN: 1432-1106
    Schlagwort(e): Key words Spatial function ; Water maze ; Procedural learning ; Cerebellum ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Recently, we demonstrated the prevalent role of cerebellar networks in the acquisition of the procedural components of spatial information by testing hemicerebellectomized (HCbed) rats in a classical spatial task, the Morris water maze (MWM). As procedures used in the water maze are a mixture of different components (that is, general procedures, exploration procedures, direct reaching procedures), for optimally solving a spatial task all procedural components must be opportunely managed. Thus, severely impaired procedural learning of cerebellar origin can be better comprehended by fractionating the procedural facets. To this aim, a two-step water-maze paradigm was employed. Normal rats were first trained to search for a hidden platform moved to a different position in each trial, utilizing a water maze setting in which visual cues were abolished by heavy black curtains surrounding the tank. In this paradigm, normal animals solved the task by using general and exploration procedures, but they could not use direct reaching skills. A subgroup of these pretrained animals was then HCbed and, after recovery from cerebellar lesion, was tested in a water maze with normal environmental cues available, a paradigm in which normal animals develop abilities for reaching the target with very direct trajectories. Pretrained HCbed animals, however, did not display the typical spatial deficits of naive HCbed rats, persisted in exhibiting the scanning strategy learned during pretraining, and never displayed direct reaching skills. In conclusion, cerebellar networks appear to be involved in the acquisition of all procedural facets necessary for shifting behavior within the maze until direct reaching of the platform. The lack of flexibility in changing exploration strategies displayed by pretrained HCbed rats is interpreted by taking into account the well-known cerebellar frontal interplay sculpting a specific cerebellar role in the acquisition of spatial procedural steps.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 126 (1999), S. 307-314 
    ISSN: 1432-1106
    Schlagwort(e): Key words Striatal dopamine depletion ; Rat ; Locomotion ; Ground reaction forces ; Gait ; Unilateral ; Kinetic ; Centre of mass
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Hemi-parkinsonian rats have preserved postural reflexes but are impaired in initiation of voluntary movements. Surprisingly, these rats can walk and run, suggesting that they can access some compensatory strategy to overcome the rigidity in their impaired limbs. The purpose of the present experiment was to investigate the locomotor compensations made by hemi-parkinsonian rats by measuring the forces exerted by the limbs on the ground throughout the stride during trotting. Rats with unilateral dopamine depletion produced by injection of 6-hydroxydopamine into the nigrostriatal bundle were trained to run back and forth in an alley for food reinforcement. Ground reaction forces were measured in three orthogonal directions using a force plate embedded in the runway. Rats were also videotaped so that limb movements were synchronized with force recordings. Although locomotion was obviously impaired, the affected limbs could support weight and provide some braking forces. In addition, the impaired hindlimb provided significant propulsive force, and a relatively large laterally directed force. Analysis of vertical movement of the centre of mass suggested that the impaired hindlimb was being used partly as a spring. The most significant abnormalities were seen during the diagonal couplet of the impaired forelimb and the unimpaired hindlimb, partly reflecting the important compensatory role of the unimpaired hindlimb. These results demonstrate that this method is useful in the analysis of hemi-parkinsonian gait and provide insights as to how rats can use an impaired limb to produce weight support and propulsion.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 126 (1999), S. 351-358 
    ISSN: 1432-1106
    Schlagwort(e): Key words Tooth pulp ; Phrenic nerve ; Electrical stimulation ; C1 spinal neuron ; Digastric electromyogram ; Somatic receptive field ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Effects of electrical stimulation of the ipsilateral tooth pulp (TP) on C1 spinal neurons were determined in 33 anesthetized rats. One hundred and seven neurons responded to TP stimulation. In 10 rats, the activity of 18 C1 spinal neurons and the amplitude of a digastric electromyogram (dEMG, n=10) increased proportionally during the TP stimulation at an intensity of 1–3 times the threshold for jaw-opening reflex (JOR). Excitatory receptive somatic fields were examined in 61 neurons. Somatic field locations of many neurons (67.2%) involved the ipsilateral face, neck, and jaw. The activity of 45 neurons was increased by both noxious pinch and brushing hair. Of the 107 C1 spinal neurons responding to TP stimulation, 55 were tested to determine the effects of electrical stimulation of the ipsilateral phrenic nerve (PN) above the heart. Twenty-eight of 55 neurons tested were excited; no change in activity was seen for the remaining 27 neurons. The activity of six neurons increased as the intensity of PN stimulation was increased. Excitatory receptive somatic fields were determined in 28 neurons, and somatic field locations of 17 neurons (60.7%) included the ipsilateral face, neck, and jaw. Both noxious pinch and brushing hair excited all 28 neurons. These results suggest that there may be the convergence of face, neck, jaw, TP, and PN afferents on the same C1 spinal neurons in the rat.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 78
    ISSN: 1432-1106
    Schlagwort(e): Key words Acetylcholine ; Brain slices ; Cerebral cortex ; Long-term depression ; Rat ; Synaptic plasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The ability of layer I activation to facilitate the induction of long-term potentiation (LTP) in layer II/III horizontal connections of motor cortex (MI) was examined in rat brain slice preparations. Field potentials evoked in layer I and layer II/III horizontal pathways were recorded from radially aligned MI sites. While theta burst stimulation (TBS) of layer II/III pathways alone failed to induce LTP, simultaneous TBS of layer I and layer II/III inputs on alternate sides of the recording electrodes induced LTP in the layer II/III input in 8 out of 13 slices (mean change +20±6%; N=13). In the same cases, the layer I connections showed mixed effects: LTP in three cases, LTD in five cases, and no modification in five slices. Despite the facilitatory effect of layer I activation on layer II/III LTP induction, we found that the critical circuitry for this effect was outside layer I. Cutting the layer I fibers selectively in the slice did not prevent layer II/III LTP induction, while cuts preserving only layer I blocked layer II/III LTP after conjoint I+II/III TBS. Cholinergic fibers were evaluated as candidates for the facilitatory effect because they branch widely in both layers and they are thought to participate in synaptic modification. The cholinergic contribution to layer II/III LTP facilitation was investigated using bath application of muscarinic antagonists. Muscarinic blockade prevented facilitation of layer II/III LTP by layer I coactivation. Instead, conjoint stimulation in 10 µM atropine produced long-term depression (LTD) of layer II/III (–18±9%; N=11) as well as of layer I (–21±6%; N=11) horizontal responses. These results indicate that connections formed within layer I are ineffective in promoting LTP in the deeper-lying horizontal connections; the critical route by which layer I stimulation influenced LTP induction required the circuitry in the deeper layers, particularly the cholinergic system. Thus, it appears that diffuse cholinergic afferents provide an additional route to regulate activity-dependent synaptic modificaton in horizontal cortical connections.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 127 (1999), S. 298-306 
    ISSN: 1432-1106
    Schlagwort(e): Key words Motor unit ; Contraction ; Stimulation pattern ; Rat ; Medial gastrocnemius
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The effects of irregularity in the pattern of stimulation on the tension produced by motor units in the rat medial gastrocnemius muscle were investigated. The effects of decreasing as well as increasing the interpulse intervals were observed for each motor unit in tetani fused to different degrees. For each motor-unit type, it was found that the effects of these changes depended on the extent of tetanic fusion. Decreasing the interpulse interval produced an increase in tension during the tetanus: the more fused the profile of tetanus, the smaller the tension increase. Increasing the interpulse interval resulted in a decrease in tetanic tension. This effect was most prominent when the tetanic fusion index was approximately 0.75. This phenomenon resulted from the prolongation in relaxation when tetanic fusion increased, thereby preventing a decrease in tension when the interpulse interval increased. We also investigated the effects of introducing a short interpulse interval (”doublet”) at the beginning of the stimulation. The doublets produced increased tetanic tension with a more fused profile. However, the doublet enhanced the sensitivity of the tetanus to increases in interpulse interval and decreased its sensitivity to decreases in interpulse intervals. Slow-twitch motor units appeared to be significantly less sensitive to both increases and decreases in interpulse interval than fast-twitch units. This suggests that slow-twitch units are better suited for producing long-lasting contractions with a constant tension level. Conversely, the high sensibility of fast-twitch units to changes in stimulation frequency enhances their participation in regulation of tension of the muscular contraction.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 80
    ISSN: 1432-1106
    Schlagwort(e): Key words Thyroid hormone ; RT-PCR ; p75 receptor ; trkA ; trkB ; trkC ; Septum ; Hippocampus ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Early postnatal application of thyroid hormones to rats results in morphological changes of the septo-hippocampal cholinergic and the hippocampal mossy fiber systems. Modulation in the expression of either neurotrophins and/or their receptors is postulated to be involved in these effects. In a recent study, we showed that, after thyroxine application, the mRNA expression of neurotrophins of the nerve-growth-factor (NGF) family is significantly upregulated both in septum and hippocampus. To test whether the neurotrophin receptors (the low-affinity neurotrophin receptor p75 and the specific high-affinity receptors trkA, trkB, and trkC) were also affected by hormone administration, newborn rats were treated daily with subcutaneous injections of thyroxine until postnatal day 12 (P12) at latest. Control animals received corresponding injections of saline. The pups were sacrificed at defined intervals from P9 to P14. The septal areas and the hippocampi were analyzed using the reverse-transcription polymerase chain reaction (RT-PCR) method for quantification of p75, trkA, trkB, and trkC mRNA levels. Analysis of variance over the total investigation period revealed no significant general increases of the gene expressions of either neurotrophin receptor, neither in the septum nor in the hippocampus, although previous results have shown marked changes in neurotrophin levels. On particular postnatal days, significant upregulation could be observed in hippocampus for trkB and trkC. From these and recent data, we conclude that modulation of neurotrophin expression rather than neurotrophin-receptor expression contributes to the morphological modifications within the hippocampal mossy fiber system and the septo-hippocampal cholinergic system.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 124 (1999), S. 241-247 
    ISSN: 1432-1106
    Schlagwort(e): Key words Melatonin ; Kainate ; Glutathione ; Apoptosis ; Excitotoxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The anti-excitotoxic efficacy of the pineal hormone melatonin was investigated in kainate-injured brains of rats. Kainate (a glutamate-receptor agonist, 2.5 nmol in 1 µl) was directly injected to unilateral striatum. Melatonin (10 mg/kg) was administrated intraperitoneally 1 h before and 1, 3, and 5 h after intrastriatal kainate injection in adult Sprague-Dawley rats. Three days after kainate injection, a significant neuronal damage was found, as determined by Nissl staining and the TUNEL method, not only in the injected striatum, but also in the ipsilateral neighboring cortex. The kainate-induced cortical apoptotic neuronal death was significantly attenuated by treatment with melatonin compared with the vehicle control group. However, no detectable changes were observed in the contralateral side of the brain in either vehicle- or melatonin-treated rats. Moreover, the biochemical results indicated that kainate can indeed induce oxidative stress, such as a decrease in the content of total glutathione (GSH), oxidized glutathione (GSSG), and an increase in the ratio of GSSG/GSH in the striatum and cortex compared with the contralateral brain regions. In the kainate-injected striatum, melatonin did not reduce the oxidative stress, but in the neighborhood of injected area-cortex, kainate-induced oxidative stress was significantly reduced by melatonin. Enhancement of glutathione-peroxidase activity was induced by intrastriatal kainate injection, not only in the cortical area of control and melatonin-treated rats, but also in striatum of control rats. However, a large elevation was found in the melatonin-treated cortex. Taking the morphological and biochemical data together, the present results suggest that melatonin functions as an antioxidant by upregulating the glutathione antioxidative defense system, thereby reducing neuronal death caused by excitotoxicity and preventing the kainate-induced damage from spreading to adjacent brain regions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 128 (1999), S. 309-314 
    ISSN: 1432-1106
    Schlagwort(e): Key words GABA ; Bromodeoxyuridine ; Proliferation ; Immunohistochemistry ; Retina ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The birthdates of GABAergic amacrine cells in the rat retina were investigated by immunocytochemistry using anti-GABA and anti-bromodeoxyuridine (BrdU) antisera. The ratio of co-localization of GABA to BrdU increased gradually from embryonic-day 13 (E13) and showed a peak value on E18 in the central retina and on E20 in the periphery. After birth, until postnatal-day 3 (P3), a few co-localized cells were observed in the inner nuclear layer (INL). However, in the peripheral retina, co-localized cells were observed in the INL and ganglion cell layer until P5. Our results suggest that the birthdates of GABA-immunoreactive cells vary, depending on cell-type and that there is a temporal lag in the GABA-immunoreactive cell production in the peripheral retina relative to the central retina.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 359 (1999), S. 228-234 
    ISSN: 1432-1912
    Schlagwort(e): Key words Natural killer ; Pentoxifylline ; Macroangiopathic patients ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The methylxanthine derivative pentoxifylline, widely used in the treatment of vascular diseases, also has numerous immunological effects. In in vitro experiments, the human natural killer cell cytotoxicity was investigated in the presence of pentoxifylline. A clinical trial involved an investigation of the natural killer cell activity in patients to whom pentoxifylline had been administered for different periods. The natural cytotoxicity in macroangiopathic patients treated with pentoxifylline was compared with that in healthy controls and that in patients with vascular diseases who did not receive pentoxifylline therapy. A total of 62 macroangiopathic patients and 20 healthy controls were investigated. The natural killer cell activity in patients receiving pentoxifylline therapy for more than a year proved to be significantly lower (P〈0.005). The presence of vascular disease did not influence the natural killer activity. In the in vitro cytotoxicity reaction, pentoxifylline at a concentration of 100 µg/ml was found to suppress the natural killer cell cytotoxicity at any stage of the reaction. The influence of pentoxifylline on the natural killer cell activity was not due to inhibition of the expression of intercellular adhesion molecule-1. However, this drug significantly decreases (P〈0.05) the apoptosis of target cells. It is presumed that the suppressor effect of pentoxifylline on natural killer cell activity should be taken into consideration in the treatment of clinical diseases where this drug is administered chronically.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 359 (1999), S. 322-330 
    ISSN: 1432-1912
    Schlagwort(e): Key words Blood pressure ; Endothelium ; Human ; Mesenteric artery ; Rat ; Smooth muscle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The majority of the findings concerning arterial physiology and pathophysiology originate from studies with experimental animals, while only limited information exists about the functional characteristics of human arteries. Therefore, the aim of the present work was to compare the control of vascular tone in vitro in mesenteric arterial rings of corresponding size (outer diameter 0.75–1 mm) from humans and Wistar-Kyoto rats. The relaxations to acetylcholine (ACh) were clearly less marked in the mesenteric arteries of humans when compared with rats. How-ever, when calcium ionophore A23187 was used as the vasodilator, the endothelium-mediated relaxations did not significantly differ between these species. The NO synthase inhibitor N G-nitro-l-arginine methyl ester (l-NAME) attenuated the relaxations to ACh and A23187 in both groups. The endothelium-independent relaxations to the β-adrenoceptor agonist isoprenaline and the nitric oxide (NO)-donor nitroprusside were somewhat lower in human arteries, while vasodilation induced by the K+ channel opener cromakalim was similar between humans and rats. Arterial contractile sensitivity to noradrenaline and serotonin was slightly lower in human vessels, whereas contractile sensitivity to KCl was similar between these species. The contractions induced by cumulative addition of Ca2+ with noradrenaline as the agonist were effectively inhibited in both groups by the calcium channel blocker nifedipine, the effect of which was clearly more pronounced in human arteries. In conclusion, the control of vascular tone of isolated arteries of corresponding size from humans and rats appeared to be rather similar. The most marked differences between these species were the impaired endothelium-mediated dilation to ACh and the more pronounced effect of nifedipine on the Ca2+-induced contractions in human arteries.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 85
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Epitheloides Hämangioendotheliom ; Leber ; Kindesalter ; Proliferation ; Apoptose ; Key words Epithelioid hemangioendothelioma ; Liver ; Childhood ; Proliferation ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary We report on a 12-year old boy suffering from malignant epithelioid hemangioendothelioma of the liver, which is a very rare tumor in childhood. The tumor was detected by ultrasound examination at the age of 10 and appeared at that time as a solitary intrahepatic nodular lesion. During the following 2 years multiple nodular lesions developed in both hepatic lobes. There were neither any suspect anamnestic findings nor abnormal clinical or laboratory data. The tumor showed the typical histomorphological, immunohistochemical, and ultrastructural features of this entity, which is usually seen in older patients. We investigated proliferative activity, apoptotic regulation, and expression of VEGF and VEGF-receptor flk-1 by means of immunohistochemical techniques. According to the known slow growth activity of these tumors we found only a few Ki-67 positive tumor cells. We did not detect any apoptotic cells using TUNEL technique. The positive immunoreaction of the tumor cells with antibodies against VEGF and VEGF-receptor flk-1 may indicate the regulation of tumor growth by angiogenetic factors. We present our findings together with a summary of the most important publications of recent years concerning these tumors.
    Notizen: Zusammenfassung Bei einem 12 Jahre alten Jungen wurde ein im Kindesalter sehr seltenes malignes epitheloides Hämangioendotheliom der Leber diagnostiziert. Im Alter von 10 Jahren fiel erstmals sonografisch ein solitärer Leberrundherd auf, im Verlauf der nächsten zwei Jahre entwickelten sich multiple Rundherde in beiden Leberlappen. Die Anamnese des Patienten war hinsichtlich möglicher prädisponierender Faktoren unauffällig. Die klinischen und laborchemischen Parameter befanden sich im Normbereich. Der Tumor wies die für diese, üblicherweise bei Erwachsenen auftretenden Entität typischen histomorphologischen, immunhistochemischen und ultrastrukturellen Merkmale auf. Mittels immunhistochemischer Untersuchungen wurde das Tumorgewebe hinsichtlich Proliferationsaktivität, Apoptoseregulation und Expression angiogenetischer Faktoren (VEGF und VEGF-Rezeptor flk-1) untersucht. Bei bekanntermaßen langsamer Wachstumstendenz dieser Tumoren fand sich ein geringer Anteil Ki-67-positiver Tumorzellen. Mittels TUNEL-Technik wurden keine Apoptosen gefunden. Die positive Immunreaktion der Tumorzellen mit Antikörpern gegen VEGF und den VEGF-Rezeptor flk-1 deutet auf eine Regulation des Tumorwachstums durch angiogenetische Faktoren hin. Die Ergebnisse werden in Verbindung mit einer Zusammenstellung der wichtigsten Publikationen der letzten Jahre über diese seltenen Tumoren diskutiert.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 86
    ISSN: 1432-198X
    Schlagwort(e): Key words Hypercalciuria ; Idiopathic hypercalciuria ; Bone mineral content ; 1 ; 25-Dihydroxyvitamin D ; Furosemide ; Ammonium chloride ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The relationship between bone mineral status and hypercalciuria is controversial. The effect on bone composition of different forms of hypercalciuria was studied in female rats made hypercalciuric by 7-week administration of oral furosemide (F, n=12), intraperitoneal 1,25-dihydroxy vitamin D (VD, n=11), or oral ammonium chloride (AC, n=12). Seven untreated rats served as controls (C). Hypercalciuria (mg/100 g per 24 h, mean ±SEM) of F (4.3±0.2), VD (4.1±0.4), and AC (3.9±0.3) groups was of similar intensity (C rats 1.3±0.1, P〈0.01). Weight and length gains and serum CO2, sodium, potassium, calcium, and phosphate were no different among the four groups. Bone was studied by dual-energy X-ray absorptiometry of left tibiae. AC rats had significantly less bone area (1.505±0.018 cm2) than VD and C (1.602±0.020 and 1.587±0.019 cm2). Bone mineral content was decreased in F (0.357±0.007 g) and AC (0.362±0.006 g) compared with VD (0.407±0.008 g) and C (0.389±0.009 g) groups. Bone mineral density was different between F (0.231±0.002 g/cm2) and VD and C rats (0.254±0.004 and 0.245±0.003 g/cm2), and also between AC (0.240±0.003 cm2) and VD rats. In these rat models, hypercalciuria of renal origin (F) and hypercalciuria caused by acid load (AC) adversely impaired bone mass.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric nephrology 13 (1999), S. 800-805 
    ISSN: 1432-198X
    Schlagwort(e): Key words In situ hybridization ; Kidney development ; Nephrogenesis ; Phosphatase activity ; Serine/threonine protein phosphatase 2A ; Protein phosphorylation ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Several lines of evidence suggest that the serine/threonine protein phosphatase (PP)2A is of vital importance for cell cycle regulation, cell differentiation, and signal transduction. This prompted us to study the expression of the mRNA for PP2A catalytic isoforms α and β in the developing rat kidney using in situ hybridization histochemistry. The expression patterns of the two isoforms were strikingly similar. Both were ubiquitously expressed in early metanephric kidneys. Later in gestation they were expressed in the nephrogenic zone. Strong expression was observed on postnatal day (PN) 10. This was followed by a downregulation at PN20, i.e., when nephrogenesis is completed. The expression in the adult kidney was very weak and mainly confined to the medulla. In a phosphatase activity assay, PP2A accounted for 78% of the total serine/threonine phosphatase activity in embryonic day 15 rat kidneys. PP1 was the main contributor to the remaining activity. In conclusion, PP2A is the major serine/threonine phosphatase in fetal kidneys. The age-dependent expression pattern supports the concept that this enzyme is of particular importance during renal morphogenesis and development.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric nephrology 13 (1999), S. 812-815 
    ISSN: 1432-198X
    Schlagwort(e): Key words Cystinosis ; Cysteamine ; Renal function ; Rat ; Prenatal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The safety of cysteamine after renal transplantation and during pregnancy is an important issue, since girls with cystinosis are in better health on cysteamine therapy and thus more likely to become pregnant. In the first study, cysteamine was given to pregnant rats on days 6.5–18.5 post conception in oral doses of 0, 37.5, 75, 100, and 150 mg/kg per day. The dams were sacrificed on day 20.5, the fetal kidneys removed and prepared for histological examination. In the second study, cysteamine was given to dams on days 6.5–19.5 post conception in oral doses of 0, 37.5, 50, and 75 mg/kg per day. Dams were allowed to give birth naturally and pups were given cysteamine on days 4–21 to yield the same oral doses of cysteamine given to the dam. Renal function was evaluated on day 35. Histological examination of fetal kidneys revealed no changes even in kidneys from fetuses with growth retardation and malformations. Furthermore, there were no alterations in renal function in offspring on day 35. These findings demonstrate that cysteamine therapy does not affect renal development in the rat. Further investigations will be required to prove whether cysteamine therapy has the potential to affect renal development in the human.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 89
    ISSN: 1432-2072
    Schlagwort(e): Key words Nicotine ; Mecamylamine ; Tolerance ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Chronic injections of nicotine in rats produce upregulation of nicotinic cholinergic receptors. It has been proposed that this upregulation is a reflection of receptor desensitization and is the basis of functional tolerance. Mecamylamine, a non-competitive antagonist that blocks activation of nicotinic receptors, does not prevent upregulation produced by nicotine injections. This suggests that receptor activation is not a prerequisite for nicotine-induced receptor upregulation. Therefore, the present experiments tested whether mecamylamine would also fail to prevent the development of tolerance to nicotine. Six daily pairings of mecamylamine (1 mg/kg SC) with nicotine did block the development of tolerance to nicotine-induced antinociception (0.35 mg/kg) and to the ability of nicotine to suppress milk intake (0.66 mg/kg). In another experiment, six daily injections of mecamylamine, when given alone, did not alter the effects of a subsequent, acute injection of nicotine (0.35 mg/kg) in inducing antinociception in rats. There was no evidence that after six pairings of mecamylamine with nicotine, the cues associated with mecamylamine delivery took on conditioned antagonistic properties. These findings suggest that, unlike the receptor upregulation that results from either continuous or repeated nicotine administration, the tolerance following a short series of intermittent nicotine injections is dependent on receptor activation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 141 (1999), S. 351-361 
    ISSN: 1432-2072
    Schlagwort(e): Key words Amphetamine ; Behavioral sensitization ; MK-801 ; NMDA receptor ; State-dependency ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Many laboratories have reported that coadministration of N-methyl-d-aspartate (NMDA) receptor antagonists with psychomotor stimulants prevents the development of behavioral sensitization and therefore concluded that NMDA receptor transmission is necessary for sensitization. According to an alternative ”state-dependency” interpretation, NMDA receptor antagonists do not prevent sensitization. Rather, they become a conditioned stimulus for the sensitized response, i.e., it is only elicited in response to combined administration of the NMDA receptor antagonist and the stimulant. This hypothesis is supported by progressive augmentation of the locomotor response to the drug combination during the induction phase, and expression of sensitization when challenged with the combination but not the stimulant alone. To test this hypothesis, rats were treated during a 6-day induction phase with amphetamine (Amph) alone or in combination with the competitive NMDA receptor antagonist CGS 19755 (10 mg/kg) or the non-competitive NMDA receptor antagonist MK-801 (0.05, 0.1 and 0.25 mg/kg). When CGS 19755 was coadministered with Amph, there was no progressive augmentation of response to the drug combination. When challenged with Amph alone, rats did not exhibit the biphasic pattern of locomotor activity characteristic of Amph sensitization. No sensitization of stereotyped behaviors was evident, although the ambulatory response was greater than that exhibited by naive rats. Results with MK-801 were complex, but progressive augmentation of response to the drug combination appeared to in part reflect sensitization to MK-801 and could be dissociated from the ability of MK-801 to prevent the development of sensitization as assessed by response to challenge with Amph alone. Many of these findings are inconsistent with predictions of the ”state-dependency” hypothesis. Moreover, the ability of NMDA receptor antagonists to prevent biochemical and electrophysiological correlates of sensitization is difficult to reconcile with the idea that sensitization develops in the presence of NMDA receptor blockade but cannot be expressed. Together, these findings suggest that the ability of NMDA receptor antagonists to prevent Amph sensitization reflects a requirement for NMDA receptor transmission during its induction.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 91
    ISSN: 1432-2072
    Schlagwort(e): Key words SSRI ; Cytochrome P450 ; Serotonin ; Microdialysis ; Norfluoxetine ; Locomotor activity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Amphetamine stimulates locomotor activity, in large part by activating central dopaminergic systems. Serotonin shares on overlapping distribution with dopamine and has been shown to modulate dopaminergic function and dopamine-mediated behaviors. The present study examined whether increasing serotonergic function, via the selective serotonin reuptake inhibitor fluoxetine, would alter the stimulatory effects of amphetamine on locomotor activity and dopamine overflow in the nucleus accumbens. In addition, the present study determined whether fluoxetine treatment would alter the metabolism of amphetamine. Results show that 5.0 mg/kg fluoxetine potentiated the locomotor activity induced by amphetamine (0.5–1.0 mg/ kg), and enhanced the increased dopamine overflow in the nucleus accumbens induced by amphetamine. Fluoxetine treatment also resulted in a higher concentration of amphetamine in the CNS. Together, these findings indicate that acute fluoxetine treatment potentiates the locomotor stimulating and dopamine activating effects of amphetamine. Further, the results indicate that fluoxetine potentiates the effects of amphetamine by decreasing the metabolism of amphetamine, probably through inhibition of cytochrome P450 isozymes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 92
    ISSN: 1432-2072
    Schlagwort(e): Key words NMDA (N-methyl-D-aspartate) ; Schizophrenia ; Prepulse inhibition (PPI) ; Sensory gating ; P50 ; Auditory evoked potentials (AEP) ; Ketamine ; d-Amphetamine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Schizophrenic patients suffer from deficits in information processing. Patients show both a decrease in P50 gating [assessed in the conditioning-testing (C-T) paradigm] and prepulse inhibition (PPI), two paradigms that assess gating. These two paradigms might have a related underlying neural substrate. Gating, as measured in both the C-T paradigm (the gating of a component of the auditory evoked potential (AEP)], and PPI can easily be measured in animals as well as in humans. This offers the opportunity to model these information processing paradigms in animals in order to investigate the effects of neurotransmitter manipulations in the brain. In order to validate the animal model for disturbances in AEP gating, d-amphetamine (0.5 and 1 mg/kg, IP) was administered. Gating of an AEP component was changed due to injection of d-amphetamine (1 mg/kg) in the same way as seen in schizophrenic patients: both the amplitude to the conditioning click and the gating were significantly reduced. Next, the effect of the N-methyl-D-aspartate (NMDA) antagonist ketamine (2.5 and 10 mg/kg, IP) was investigated to assess its effects in the two gating paradigms. It was found that ketamine (10 mg/kg) did not affect gating as measured with components of the AEP. However, ketamine (10 mg/kg) disrupted PPI of the startle response to the extent that prepulse facilitation occurred. Firstly, it is concluded that AEP gating was disrupted by d-amphetamine and not by ketamine. Secondly, PPI and the C-T paradigm reflect distinct inhibitory sensory processes, since both paradigms are differentially influenced by ketamine.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 93
    ISSN: 1432-2072
    Schlagwort(e): Key words Alcoholism ; Alcohol drinking ; Alcohol intake ; Calcium channells ; Genetic model of alcoholism ; Pharmacotherapy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Drugs which possess selective actions on a given voltage operated calcium (Ca2+) channel (VOCC) are reportedly involved in the pharmacological actions of alcohol. Recently it was shown that the 1,4-dihydropyridine (−)-BAY k 8644, an L-type VOCC agonist, reduces alcohol intake relatively selectively in the genetic drinking AA rat. This study determined whether (−)-BAY k 8644 would alter volitional alcohol drinking in two other genetic models of alcoholism, male P rats and a new strain of male and female high ethanol preferring (HEP) rats. By use of a standard 10-day preference test for water versus 3 to 30% alcohol, the maximally preferred concentration of alcohol was first determined for each rat individually, i.e. 9%, 13% or 15%. Then the rats were allowed free access over 24 h or limited access to alcohol for only 2 h, during which time the intakes of water and preferred solution of alcohol were recorded. After the drinking patterns stabilized for 4 days, saline, a solutol vehicle solution or (−)-BAY k 8644 was administered: (1) in a dose of 0.125, 0.25 or 0.5 mg/kg given intraperitoneally twice daily for 4 days during free access to alcohol; and (2) for 3 days in a dose of 0.125 or 0.25 mg/kg given subcutaneously 30 min prior to 2 h of limited access to alcohol. Fluid intakes were recorded for either 4 or 8 days after limited and free access conditions, respectively. Whereas the control solutions were without effect during 24 h access, (−)-BAY k 8644 caused a significant dose-dependent suppression of up to 80% in absolute g/kg and proportion of alcohol to total fluid consumed; this decline persisted in the post drug period. During the limited access paradigm, (−)-BAY k 8644 similarly reduced alcohol drinking maximally within the first 15 min of presentation of alcohol; again, this reduction persisted over the remaining 105 min of alcohol access. Also, individual levels of blood alcohol declined concurrently with the suppression of drinking. These results demonstrate that (−)-BAY k 8644 possesses a short latency of action on alcohol intake and that its salutary effects on drinking persist after the drug is terminated. Finally, the hypothesis that L-type calcium channel agonists may be useful as a therapeutic adjunct in the treatment of alcoholism is extended.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 142 (1999), S. 302-308 
    ISSN: 1432-2072
    Schlagwort(e): Key words Alcohol ; Beer ; Craving ; Rat ; Naloxone ; SR 141716 ; Ritanserin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rats were given two weeks of home cage access to either “near-beer” (a beverage that tastes like beer but contains 〈0.5% ethanol v/v) or near-beer with added ethanol (4.5% v/v), which is simply referred to as “beer”. The two groups of rats (near-beer and beer) were then trained on a “lick-based progressive ratio paradigm” in operant chambers in which an ever increasing number of licks had to be emitted for each successive fixed unit of near-beer or beer delivered. Break points (the ratio at which responding ceased) for near-beer and beer were approximately equal under baseline conditions. Rats were then tested for the effects of the 5HT2A/2C receptor antagonist ritanserin (0.625, 2.5 or 10 mg/kg), the opioid receptor antagonist naloxone (0.625, 2.5 or 10 mg/kg) or the cannabinoid CB1 receptor antagonist SR 141716 (0.3, 1 or 3 mg/kg). All three drugs caused a dose-dependent reduction of break-points and locomotor activity in both the beer and near-beer groups. However, the effects of SR 141716 and naloxone, but not ritanserin, on break-points were significantly more pronounced on rats drinking beer compared to those drinking near-beer. There were no such differential effects of any of the drugs on locomotor activity across the two groups. These results suggest that both SR 141716 and naloxone differentially affect the motivation to consume alcoholic beverages and may thus have potential as drugs for the treatment of alcohol craving.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 143 (1999), S. 54-63 
    ISSN: 1432-2072
    Schlagwort(e): Key words Nicotine ; Midazolam ; Caffeine ; Cocaine ; Amphetamine ; Pentobarbitone ; Ethanol ; Drug discrimination ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rationale: Studies of the discriminative stimulus effects of drug mixtures provide an approach to polydrug abuse and studies on single drugs with multiple effects. Objective: This study was designed to investigate whether the use of the AND-OR procedure increases the specificity of drug mixture discriminations. Methods: Rats were trained to discriminate a mixture of amphetamine (0.4 mg/kg) plus pentobarbitone (10 mg/kg) from saline (AND-discrimination, n = 8) or to discriminate the same mixture from its component drugs alone (AND–OR discrimination, n = 9). The studies used two-lever operant procedures with a tandem variable interval 1-min fixed ratio 10 schedule of food reinforcement. Results: Under AND-discrimination conditions, there was partial generalization to nicotine and midazolam when each drug was administered singly, and there was no generalization to cocaine, caffeine or ethanol. With the AND-OR discrimination, there was no generalization to any of the preceding drugs administered singly. In “single substitution” tests, nicotine or midazolam was co-administered with the training doses of pentobarbitone and amphetamine, respectively; there was full generalization in the AND-discrimination and partial generalization under AND-OR conditions. Cocaine co-administered with pentobarbitone generalized fully under both procedures, but the dose of cocaine needed was much larger in the AND-OR than in the AND-discrimination. In “dual substitution” tests, mixtures of two novel substances were tested. Mixtures of either nicotine plus midazolam or caffeine plus ethanol produced very marked generalization under AND-discrimination conditions, but were without significant effect in the AND-OR procedure. Throughout the studies, in every instance where comparisons were made, generalization was greater or occurred at lower doses under AND- than under the AND-OR discrimination. Conclusions: The study yielded extensive evidence supporting the hypothesis that the AND-OR discrimination procedure increases the specificity of discriminations based on drug mixtures.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 96
    ISSN: 1432-2072
    Schlagwort(e): Key words BC264 ; Cholecystokinin ; CCKB receptor ; Memory ; Ageing ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rationale: The implication of CCKB receptors in cognitive processes is far from fully understood. Objective: The present study investigated the effect of propionyl-BC264, a selective agonist of CCKB receptors, in young and old rats. Methods: Cognitive functions were studied in a two-trial recognition memory task developed in our laboratory. Results: It was shown that propionyl-BC264 enhanced information processing in young as well as in old rats when injected (10 μg/kg; IP) immediately after the acquisition phase and before the retrieval trial but not before the acquisition trial. This cognitive enhancing effect was blocked by prior administration of L 365,260, a selective CCKB receptor antagonist. Conclusions: In view of the fact that BC264 is devoid of anxiogenic effects, it could be of value in the treatment of cognitive impairments associated with both normal and pathological ageing.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 145 (1999), S. 153-161 
    ISSN: 1432-2072
    Schlagwort(e): Key words Cocaethylene ; Cocaine ; Alcohol ; Interaction ; Schedule-controlled responding ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Cocaethylene is a unique metabolite of cocaine, produced only in the presence of alcohol. This metabolite is pharmacologically, physiologically and behaviorally active. Further, it has been reported to interact pharmacokinetically with both cocaine and alcohol, an interaction that may mediate, in part, the interaction of cocaine and alcohol. Although cocaethylene has been shown to interact with both cocaine and alcohol, behavioral assessments of these interactions are limited. Objectives: To examine directly the behavioral interactions between cocaethylene and cocaine and between cocaethylene and alcohol, the present study assessed the effects produced by these combinations on schedule-controlled responding. Methods: Rats were first administered cumulative doses of cocaethylene, cocaine and alcohol to assess their effects alone on responding. Following this, doses of cocaethylene were combined with cumulative doses of cocaine or alcohol. Additionally, doses of cocaine or alcohol were given in combination with cumulative doses of cocaethylene. Results: When administered alone, cocaethylene, cocaine and alcohol produced dose-related decreases in responding. Further, cocaethylene shifted the dose–response functions for both cocaine and alcohol to the left and down, while cocaine and alcohol shifted the dose–response function for cocaethylene to the left and down. An isobolographic analysis revealed that these interactions were additive in nature. Conclusions: The present study suggests behavioral interactions between cocaethylene and cocaine and between cocaethylene and alcohol. The contribution of cocaethylene to the enhanced effects produced by the co-administration of cocaine and alcohol was discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 98
    ISSN: 1432-2072
    Schlagwort(e): Key words Ibogaine ; Cocaine ; Dose-response ; Locomotor activity ; Sensitization ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Results of single-dose studies suggest that the effects of pretreatment with the putative anti-addictive compound, ibogaine, on drug-induced locomotor behavior depends on the previous drug history of the animal. Objectives: To compare the effects of ibogaine pretreatment on the dose-locomotor response function for cocaine in rats treated chronically with either saline or cocaine. Methods: Rats were chronically treated with either cocaine (15 mg/kg, IP, once daily for 5 days, followed by 2 week withdrawal) or saline. Ibogaine (40 mg/kg, IP) or vehicle was administered and 19 h later, a cocaine dose-locomotor response test was conducted (0, 5, 10, 20 and 40 mg/kg, IP). Results: Chronic cocaine administration augmented the locomotor response to cocaine in chronic cocaine-treated rats, compared to acutely treated controls. Ibogaine pretreatment enhanced the locomotor effects of cocaine in both chronic and acute cocaine groups. Furthermore, due to the shape of the dose-response curve, in chronic cocaine but not in acute cocaine rats, ibogaine pretreatment enhanced the locomotor response to 5 and 10 mg/kg cocaine while decreasing the locomotor response to 40 mg/kg cocaine. Conclusions: These data demonstrate definitively that ibogaine can enhance sensitivity to the locomotor stimulant effects of cocaine, an effect which depends, in part, on the previous cocaine history of the animal.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    ISSN: 1432-2072
    Schlagwort(e): Key words Dextromethorphan ; Dextrorphan ; Phencyclidine ; Self-administration ; Drug discrimination ; Monkey ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Dextromethorphan (DXM) and its metabolite, dextrorphan (DXO) have neuroprotective and anticonvulsant properties through their activity as N-methyl-d-aspartate (NMDA) receptor channel blockers. Based on this receptor activity, coupled with reports of DXM abuse, both were evaluated for abuse potential and phencyclidine (PCP)-like behavioral effects in two animal models. Objectives and methods: The discriminative stimulus properties of DXO and DXM were tested in rats (3–56 mg/kg DXM, i.p. and 2.2–40.9 mg/kg DXO, i.p.) and rhesus monkeys (0.3–10 mg/kg DXM, i.m. and 0.25–8.0 mg/kg DXO, i.m.) trained to discriminate PCP from saline using a standard two-lever drug-discrimination paradigm under a fixed-ratio (FR) schedule of food reinforcement. In a second set of experiments, i.v. self-administration of DXO (10–100 µg/kg/infusion) and DXM (10–1000 µg/kg/infusion) were tested under a FR schedule of reinforcement in monkeys trained to lever press for infusions of PCP during daily 1-h sessions. Results: In rats, both DXM and DXO produced a dose-dependent substitution for PCP. When tested in monkeys, DXM yielded partial (1 monkey) and full (2 monkeys) substitution for PCP, while DXO substituted fully for PCP in all four subjects tested. In the self-administration study, in five of the six subjects, at least one dose of DXM served as a positive reinforcer, maintaining infusion rates above those for saline. For DXO, at least one dose maintained infusion numbers well above mean saline infusion numbers in all subjects. Conclusions: Taken together, these data show that DXM has some PCP-like effects in rats and monkeys, but that they are more reliably produced by its metabolite, DXO. Thus, high doses of DXM may have some PCP-like abuse potential in humans but this potential may be associated with, or enhanced by, metabolism of DXM to DXO.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    ISSN: 1432-2072
    Schlagwort(e): Key words Nicotinic receptor ; Dorsal hippocampus ; Anxiety ; Phobia ; Elevated plus-maze ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract   Rationale: The elevated plus-maze provides a test situation in which distinctive states of anxiety are elicited on trials 1 and 2 and the dorsal hippocampus has previously been shown to mediate the anxiogenic effects of (–)-nicotine in the social interaction test. Objective: To determine the effects of a wide dose range of (–)-nicotine on trial 1 and 2 in the plus-maze after systemic administration and whether the dorsal hippocampus is a site mediating the anxiogenic effect of nicotine. Methods: (–)-Nicotine (0.001, 0.005, 0.01, 0.05, 0.1, 0.5 and 1 mg/kg) was injected IP 30 min before testing for 5 min in the plus-maze. Rats receiving dorsal hippocampal infusions received bilateral infusions of 0.5 μl of artificial CSF or (–)-nicotine (0.1, 1, 4 or 8 μg). The needle was left in place for 50 s after injection and testing took place 3 min later. Rats tested on trial 1 were naive to the plus-maze, those tested on trial 2 had received a previous 5-min undrugged exposure to the maze 48 h earlier. Results: Low doses of (–)-nicotine (0.001, 0.005, 0.01, 0.05 and 0.1 mg/kg, IP) were without effect on either trial, but higher doses (0.5 and 1 mg/kg, IP) had anxiogenic effects on both trials, as shown by decreases in percentage time spent and percentage entries onto the open arms. Infusion of (–)-nicotine (0.1, 1, 4 and 8 μg) bilaterally into the dorsal hippocampus was without effect on trial 1, but 1 μg had an anxiolytic effect on trial 2, shown by an increased percentage time spent on the open arms. Conclusions: The results on both trials in the plus-maze after systemic administration of nicotine add to previous reports from the social interaction test that high doses of nicotine have anxiogenic effects. However, the effects of nicotine in the dorsal hippocampus are different in all three anxiety tests (anxiogenic in social interaction, ineffective on trial 1, anxiolytic on trial 2) showing that nicotinic cholinergic control in this brain region may vary depending on the state and/or type of anxiety generated by the test. The brain region(s) underlying the anxiogenic effects of IP nicotine on both trials in the plus-maze remain to be identified.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...