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  • 1999  (1.850)
  • Chemistry  (1.469)
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  • 1995-1999  (1.850)
  • 1980-1984
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  • 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
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Trauma und Berufskrankheit 1 (1999), S. S92 
    ISSN: 1436-6274
    Schlagwort(e): Schlüsselwörter Wachstumsalter ; MRI ; Beckenfraktur ; Wirbelsäulenfraktur ; Key words Childhood ; Magnetic resonance imaging ; Pelvic fracture ; Spinal injury
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Abstract According to the literature, from 1950 to 1995 the overall risk for children of sustaining a fracture of the spinal column or the pelvic ring doubled, the main reason being the increasing incidence of high-energy trauma caused by newly popular sporting activities such as skateboarding, inline skating and mountain biking. Nonetheless, even specialized pediatric level I trauma centers in Europe and the United States of America report an incidence of below 5% for severe spinal injuries and fractures of the pelvis. Although these specific injury patters are seen relatively infrequently, whenever present they are still highly indicative of high-velocity injury mechanisms, frequently revealing a combination of injuries – each of which would be serious in itself – involving the body cavities and the soft tissues of the trunk an extremities. In summary, spinal cord injuries and pelvic ring fractures are rare but can be serious: cervical and spinal cord injuries without radiological abnormality appear to be more frequent than in adults, and the availability of nuclear magnetic imaging technologies has helped in the diagnosis of unsuspected cord injury in children. In addition, retrospective analysis of purely nonoperative management of highly unstable C-type injuries of the spine and the pelvic ring reveal some unsatisfactory results, so that specifically for these injury morphologies the alternative of an operative strategy might be considered. The purpose of this presentation is to discuss various injury patterns in which an operative concept could be considered, particularly for a multiply injured child.
    Notizen: Zusammenfassung Verletzungen des Rückenmarks und Sprengungen des knöchernen Beckenrings liegen im Kindesalter auch im Krankengut spezialisierter Zentren unter 5%. Besonders beachtenswert erscheint hierbei, daß Rückenmark- und besonders Halswirbelsäulenverletzungen v. a. beim Kind häufig keine ossäre Mitbeteiligung der Wirbelsäule zeigen und erst durch kernspintomographische Diagnostik erfaßt werden können. Desgleichen zeigt sich bei der retrospektiven Auswertung, daß ein pauschales, rein konservatives Management aller Verletzungstypen, d. h. v.a. der sog. C-Verletzungstypen an der Wirbelsäule und am Becken, z. T. unbefriedigende Behandlungsergebnisse zeigt und daher zunehmend bei bestimmten, im weiteren näher besprochenen Verletzungskonstellationen ein eher operatives Grundkonzept diskutiert wird. Neue Erkenntnisse zur Diagnostik und Therapie der Wirbelsäulen- und Beckenverletzung beim Kind liegen insofern vor, als 1. neuere epidemiologische Erhebungen heute eine präzisere, d. h. nicht nur empirisch gesicherte Unterscheidung der selten von eher regelmäßig anzutreffenden Verletzungstypen und Frakturmorphologien erlauben, 2. durch vergleichsweise „neue“ Sportarten wie „Scate-boarding“ und „Mountain-biking“ ganz generell eine statistisch belegte Zunahme von Hochrasanztraumen und komplexen Verletzungsmustern beim Kind beobachtet werden kann sowie 3. generell v.a. beim mehrfachverletzten Kind heute eine eher aggressivere Gangart, d. h. ein in bestimmten Einzelaspekten eher operatives Versorgungskonzept angestrebt wird. Gegenstand der vorliegenden Arbeit sind 1. eine Analyse der als besonders bedeutsam erkannten Verletzungsformen sowie 2. eine Darstellung der heute in Veränderung begriffenen Behandlungskonzepte v.a. beim mehrfachverletzten Kind.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1436-2023
    Schlagwort(e): Key words: hip ; acetabulum ; labrum ; MRI ; radial-sequence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract: We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15°-intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European food research and technology 209 (1999), S. 400-406 
    ISSN: 1438-2385
    Schlagwort(e): Key words Pumpkin seed oil ; Oil adulteration ; Δ7-Phytosterols ; Sample clean-up procedure ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  A simple and accurate method for the determination of phytosterols by capillary gas chromatography was developed for the analysis of the seeds and oil of the pumpkin Cucurbita pepo L., the naked seed variety growing in the southern Styrian parts of Austria. After extraction of the oil and saponification, the remaining unsaponifiable material was isolated and purified using silica gel columns. For greater volatility, the sterols were derivatised to trimethylsilylethers, and gas chromatography was performed on a column of high polarity, allowing separation of the Δ5-sterols from the Δ7-sterols and thus yielding a typical chromatographical pattern. Quantification of the phytosterols using 5α-cholestan or cholesterol as internal standards led to a method of high accuracy. Comparison of the chromatographic pattern of the phytosterol fraction of pumpkin seed oil with those of other vegetable oil samples permitted the use of this method to detect adulteration of pumpkin seed oil.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Surgical and radiologic anatomy 20 (1999), S. 413-417 
    ISSN: 1279-8517
    Schlagwort(e): Penis ; Ligaments ; MRI ; Erection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The suspensory system of the penis acquires clinical importance in reparative surgery, traumatology and through its role in erection. The aim of this study was to identify the different anatomic structures constituting the suspensory ligament by dissection and by magnetic resonance imaging (MRI). Ten unembalmed male subjects were used for dissection of the region of the base of the penis. Ten volunteer patients underwent MRI of the penis before and after the injection of prostaglandin (PGE1). The suspensory apparatus consisted of separate ligamentous structures: the fundiform ligament, which is lateral, superficial and not adherent to the tunica albuginea of the corpora cavernosa; the suspensory ligament properly so-called, further back, stretching between the pubis and the tunica albuginea of the corpora cavernosa and consisting of two lateral, circumferential, and one median bundles, which circumscribed the dorsal vein of the penis. These structures were identifiable in MRI and their supporting role was evidenced during tests of erection. The suspensory ligament seemed to maintain the base of the penis in front of the pubis and to behave as a major point of support for the mobile portion of the penis during erection.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Italian journal of neurological sciences 20 (1999), S. 247-249 
    ISSN: 1126-5442
    Schlagwort(e): Key words Superficial siderosis of the central nervous system ; MRI ; Anticoagulant therapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Superficial siderosis of the central nervous system is a rare condition characterized by deposition of haemosiderin in the leptomeninges and in the subpial layers of the brain and spinal cord. With the widespread use of magnetic resonance imaging, an increasing number of cases of superficial siderosis are being discovered, secondary forms being more frequent than idiopathic ones. We report a 78-year-old man in oral anticoagulant therapy, who presented neurosensory hearing loss, gait ataxia and spastic paraparesis. Magnetic resonance imaging suggested the diagnosis of superficial siderosis of the central nervous system, without an evident bleeding source.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Italian journal of neurological sciences 20 (1999), S. 303-307 
    ISSN: 1126-5442
    Schlagwort(e): Key words Lyme disease ; Chronic neuroborreliosis ; Children ; MRI ; Demyelinating disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Lyme disease is a polymorphic and multisystemic disease caused by Borrelia burgdorferi. Neurological manifestations are found in 10%–50% of cases. We present 2 cases followed for 5 and 6 years of chronic relapsing-remitting neuroborreliosis. Diagnosis of neuroborreliosis in these cases was based on serum and cerebrospinal fluid findings. We discuss clinical, neurophysiological, laboratory and instrumental aspects regarding the difficulties of reaching a correct diagnosis. Further studies, especially in the field of immunology, should help identify the mechanisms responsible for the disease becoming chronic. With this knowledge, it may be possible to design immunological therapies for relapses, and to prevent the evolution of the disease.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; RT/PCR ; Protooncogene ; ets-2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Protooncogenes (PO) play a crucial role for brain biology and pathology. Only the concerted action of protooncogenes enables normal brain development. The reliable and sensitive quantification of brain PO is still holding centre stage in neurobiological research. The aim of our study was therefore the determination of PO in minute amounts of brain areas. For this purpose we decided to apply the most sensitive detection principle of competitive reverse transcriptase polymerase chain reaction using capillary electrophoresis and laser-induced fluorescence detection. We selected the PO ets-2 for our studies as this transcription factor was shown to be involved in neurodegenerative disease. As little as 10ng of total RNA each were extracted from 5 different regions of human postmortem brain and used in the assay system. Our results revealed that the ets-2 gene transcript was detectable at the atto-gram level in the brain (54.5 ± 17.7 ag/ 10 ng RNA in the occipital lobe, 34.2 ± 7.5 in temporal lobe, 40.2 ± 15.6 in the frontal lobe, 31.4 ± 15.7 in the cerebellum, and undetectably low in the parietal lobe). This is the first report at this sensitivity level providing neurobiology with a powerful analytical tool.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 71-77 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Marathon ; Endurance exercise
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The sulphonated amino acid taurine increased significantly in the plasma of trained athletes after three endurance exercises of different duration and intensity, a 90 min run on a treadmill at 75% of an individual's VO2 peak, a Marathon, 42.2km and a 100km run, by 19%, 77% and 36%, respectively. Such results indicated that the speed at which the exercise is per formed, referred to as the intensity, rather than the duration of the exercise, correlated with the elevated taurine levels possibly indicating its release from muscle fibres. The plasma amino acid pool decreased significantly in relationship with the duration of the exercise, caused by their utilisation for glucogenesis. The possible sources of the increased plasma taurine are discussed.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 369-376 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Non-proteinogenic dipeptides ; Dehydrodipeptides ; Diastereoselectivity ; N-Boc-Dehydroamino acids ; Asymmetric hydrogenation ; Chiral rhodium catalysts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary N-Boc protected non-proteinogenic dipeptides with D,L-and L,L-configuration were prepared by catalytic asymmetric hydrogenation of the corresponding dehydrophenylalanyl-(L)-phenylalanine derivatives. The configuration of the new stereogenic centre depends first of all on the catalyst configuration and is less influenced by the substrate configuration. Diastereomeric excesses in the range of 80–96% de could be increased up to 99% by recrystallization. Analytical data of selected new compounds are given.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Polyclonal antibodies ; Phosalone ; Immunodetection ; Hapten synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Hapten synthesis for the production of specific insecticide phosalone polyclonal antibodies was carried out starting from an intermediate of the phosalone synthesis, 6-chloro-2-benzoxazolone1. Two haptens containing different spacers have been prepared: N-5-carboxypentyl-6-chloro-2-benzoxazolone7 and N-(2-oxo-3-aza-5-carboxypentyl)-6-chloro-2-benzoxazolone12. Each of these two haptens conjugated to bovine serum albumine (BSA) was used to immunize four rabbits. Immunoassays of phosalone were performed with ELISA using solid-phase bound hapten thyroglobulin conjugate and horseradish peroxidase labelled goat antirabbit IgG. The more sensitive response was observed when the antiserum obtained from the rabbit immunized with the hapten-BSA conjugate containing the N-2-oxo-3-aza-5-carboxypentyl spacer was in competition with the same hapten coupled to thyroglobulin. An identical response was obtained under the same conditions when using benzoxazolone instead of phosalone as competitor, showing a good recognition of the specific aromatic part of the organophosphate insecticide phosalone. Reduction of coating conjugate concentration (from 2 to 0.05μg/well) and also the use of heterologous coating protein instead of homologous did improve the sensitivity, resulting in a concentration of phosalone required to inhibit binding by 50% of 2 mg/l and a detection limit of 0.02 mg/l.
    Materialart: Digitale Medien
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  • 12
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Liver ; Hepatic damage ; Carbon tetrachloride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aims of the present study were to assess the changes of individual plasma amino acid levels in relation (1) to the severity of liver damage and (2) to the process of liver recovery. Acute liver injury was induced by an intragastric administration of CCl4 diluted in olive oil in doses of 2, 4 and /or 6 g of CCl4 per kg b.w. The control rats received olive oil only. Animals were sacrificed at 16, 24, 48 and 96 hours after treatment. The severity of liver injury was assessed by histological examination, by changes in ALT and AST in the blood plasma and by changes in liver weight. Statistical analysis was carried by ANOVA, p 〈 0.05 was considered significant. The Spearman rank correlation coefficient was used as a measure of the degree of linear relationship between variable and dose. In the period of the development of acute liver damage, i.e. at 16 and 24 hours after treatment, an increase in blood plasma amino acid levels and positive correlations with the dose of CCl4 were observed for most individual amino acids. The only exception was arginine which decreased in a dose dependent manner. At a phase of liver recovery, i.e. at 48 and 96 hours after CCl4 treatment, the concentrations of some individual amino acids decreased below the control values. The negative correlation with the dose of CCl4 occurred for taurine and isoleucine (at 48 hours) and taurine, threonine, valine, methionine, isoleucine and leucine (at 96 hours).
    Materialart: Digitale Medien
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  • 13
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Alanine ; Fatty acids ; Glutamine and glutamate synthesis ; Glycerol and lactate metabolism ; Malate-aspartate shuttle ; Rabbit kidney-cortex tubules ; Renal gluconeogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In isolated rabbit renal cortical tubules, glucose synthesis from 1 mM alanine is negligible, while the amino acid is metabolized to glutamine and glutamate. The addition of 0.5 mM octanoate plus 2 mM glycerol induces incorporation of [U-14C]Alnine into glucose and decreases glutamine synthesis, whereas oleate and palmitate in the presence of glycerol are less potent than octanoate. Gluconeogenesis is also significantly accelerated when glycerol is substituted by lactate. In view of an increase in14CO2 fixation and elevation of both cytosolic and mitochondrial NADH/NAD+ ratios, the activation of glucose formation from alanine upon the addition of glycerol and octanoate is likely due to (i) stimulation of pyruvate carboxylation, (ii) increased availability of NADH for glyceraldehyde-3-phosphate dehydrogenase and (iii) elevation of mitochondrial redox state causing a diminished provision of ammonium for glutamine synthesis. The induction of gluconeogenesis in the presence of alanine, glycerol and octanoate is not related to cell volume changes. The results presented in this paper show the importance of free fatty acids and glycerol for regulation of renal gluconeogenesis from alanine. The possible physiological significance of the data is discussed.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 79-89 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Anti-neoplastic amino acids ; Purine and DNA synthesis inhibitors ; PRPP amido transferase and IMP dehydrogenase inhibitors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 4-Hydroxyproline di- and tri-peptides and N-cbz-hydroxypropylglycinamides were observed to be potent cytotoxic agents against the growth of suspended single cells, L-1210, Tmolt3, and HeLa-S3. The agents were not as potent against the growth of cultured solid tumor cells. Selected derivatives were investigated for their mode of action in Tmolt3 leukemia cells. The compounds selectively inhibited DNA synthesis at 50 and 100smM. The target site of action of the agents appeared to be the purinede novo pathway with marked inhibition of the activities of the two regulatory enzymes of the pathway, i.e. PRPP amido-transferase and IMP dehydrogenase. d[NTP] pools were reduced by the agents consistent with their overall reduction of DNA synthesis. Other marginally inhibited targets of the agents were r-RNA polymerase and TMP-kinase activities. The DNA molecule itself did not appear to be a target of these agents.
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  • 15
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Targeting ; Mitochondria ; Chloroplasts ; Cysteine synthase ; Transit peptide ; Transgenic plants ; Processing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cysteme synthase, the key enzyme for fixation of inorganic sulfide, catalyses the formation of cysteine from O-acetylserine and inorganic sulfide. Here we report the cloning of cDNAs encoding cysteine synthase isoforms fromArabidopsis thaliana. The isolated cDNA clones encode for a mitochondrial and a plastidic isoform of cysteine synthase (O-acetylserine (thiol)-lyase, EC 4.2.99.8), designated cysteine synthase C (AtCS-C, CSase C) and B (AtCS-B; CSase B), respectively.AtCS-C andAtCS-B, having lengths of 1569-bp and 1421-bp, respectively, encode polypeptides of 430 amino acids (∼45.8 kD) and of 392 amino acids (∼ 41.8 kD), respectively. The deduced amino acid sequences of the mitochondrial and plastidic isoforms exhibit high homology even with respect to the presequences. The predicted presequence of AtCS-C has a N-terminal extension of 33 amino acids when compared to the plastidic isoform. Northern blot analysis showed thatAtCS-C is higher expressed in roots than in leaves whereas the expression ofAtCS-B is stronger in leaves. Furthermore, gene expression of both genes was enhanced by sulfur limitation which in turn led to an increase in enzyme activity in crude extracts of plants. Expression of theAtCS-B gene is regulated by light. The mitochondrial, plastidic and cytosolic (Hesse and Altmann, 1995) isoforms of cysteine synthase ofArabidopsis are able to complement a cysteine synthasedeficient mutant ofEscherichia coli unable to grow on minimal medium without cysteine, indicating synthesis of functional plant proteins in the bacterium. Two lines of evidence proved thatAtCS-C encodes a mitochondrial form of cysteine synthase; first, import ofin vitro translation products derived from AtCS-C in isolated intact mitochondria and second, Western blot analysis of mitochondria isolated from transgenic tobacco plants expressing AtCS-C cDNA/c-myc DNA fusion protein.
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  • 16
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Non-proteinogenic optically active amino acids ; Dehydroamino acids ; Chiral rhodium catalysts ; Asymmetric hydrogenation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary (Z)-α-[(Benzyloxy)- or (tert.-butyloxy)carbonylamino]-β (thienyl)-or (furyl)-acrylic acids and their esters were prepared by known methods and hydrogenated to the corresponding optically active alanine derivatives with optical yields in the range of 58–93% ee using the cationic rhodium complex of “PROPRAPHOS”.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; L-Tryptophan ; Serum albumin ; Transport ; L-Tryptophan depletion ; α-Methyl-DL-tryptophan ; Analbuminemic rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The role of serum albumin in the transport of orally administered L-tryptophan (Trp) into rat tissues was examined using analbuminemic and Sprague-Dawley (SD) rats with and without a-methyl-DL-tryptophan (AMT)-induced Trp depletion. Trp was orally administered to rats 16h after AMT or 0.85% NaCl administration, when liver tryptophan 2,3-dioxygenase and protein synthetic activities in AMT-treated rats were similar to those of 0.85% NaCl-treated rats. After oral Trp administration, regardless of the presence or absence of Trp depletion, free serum Trp concentrations were similar in the analbuminemic and SD rats, while total serum Trp concentrations were lower in analbuminemic rats than in SD rats. Although liver, brain, and muscle Trp concentrations after oral Trp administration under Trp depletion were lower in analbuminemic rats than in SD rats, the ratio of the liver Trp concentration in analbuminemic rats to that in SD rats was smaller than that of the brain or muscle Trp concentration. These results suggest that variations in serum albumin levels could affect the transport of orally administered Trp into the liver of rats with Trp depletion.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 107-111 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Tissue protein synthesis ; Stable isotope amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The tracers L15N-proline and L(1-13C)-leucine were used to explore the synthesis of skin proteins in vivo in rabbits. They orally received a single dose containing an equimolecular mixture of L(1-13C)-leucine and L15N-proline. The changes in the amounts of these tracers in blood and skin were monitored for a total of 8 h. The data showed the appearance of the two tracers in blood within 15 min and their clearance in 8h. They were both rapidly (15 min) incorporated into skin proteins, but more proline was incorporated than leucine. We therefore consider L15N-proline to be a better tracer than L(1-13C)-leucine for studying protein metabolism in the skin.
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  • 19
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine ; Kainic acid ; Epilepsy ; Anticonvulsants ; Neuroprotection ; Excitatory amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Male Sprague-Dawley rats received TAU supplementation (1.5% in drinking water) or TAU deficient diets for 4 weeks to test for a possible neuroprotective role of TAU in KA-induced (10 mg/kg s.c.) seizures. TAU supplementation significantly increased serum and hippocampal TAU levels, but not TAU content in temporal cortex or striatum. TAU deficient diets did not attenuate serum or tissue TAU levels. Dietary TAU supplementation failed to decrease the number or latency of partial or clonic-tonic seizures or wet dog shakes, whereas a TAU deficient diet decreased the number of clonictonic and partial seizures. This study does not support previous observations of an anticonvulsant effect of TAU against KA-induced seizures. KAtreatment decreasedα 2-adrenergic receptor binding sites and TAU content in the temporal cortex across all dietary treatment groups, supporting previous evidence of severe KA-induced damage and neuronal loss in this brain region.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 191-213 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Enzymatic resolution ; Ester hydrolysis ; Proteases ; Lipases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The present review outlines recent examples of enzyme-based resolution procedures for amino acids via the hydrolysis of their esters. The resolutions have been achieved by using proteases (α-chymotrypsin, subtilisin and other microbial proteases, and sulfhydryl proteases of plant origin) and lipases. Relevant work utilizing yeast and other microbial cells is also included.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 251-272 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Unusual amino acids ; Aspartic acidβ-semialdehyde ; Aspartaldehyde ; 2-Amino-4-oxobutyric acid ; Enantioselective synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Strategies for the synthesis of optically active aspartaldehyde derivatives are reviewed. Most of them are using the chiral pool: allylglycine or naturally occurring homoserine, aspartic acid or methionme and side chain modifications. This will be developed in the first part. Some other original routes are also displayed in the second part. Different aspects of each strategy are discussed: the nature and number of steps, the problem of protecting groups, the price and availability of starting materials. Some synthetic applications of such interesting chiral synthons are shown in the last part.
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  • 22
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Dipeptide derivatives ; Non-proternogenic optically active dipeptide esters ; Dehydrodipeptides ; Chiral rhodium catalysts ; Asymmetric hydrogenation ; Diastereoselectivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary N-[(Z)-N-Benzoyl- orN-Boc-(2-fluorophenyl)dehydroalanyl]-(R)-or (S)-phenylalanine esters were synthesized and hydrogenated to give the corresponding dipeptide derivatives with optical yields in the range of 53–87%de using the cationic rhodium complexes of PROPRAPHOS and BPPM. The efficiency of chiral diphosphine ligands as well the effect of the chiral center in the substrate on the catalytic asymmetric induction was studied.
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  • 23
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Phytotoxin AS-I analogues ; FAB ; PD ; ESI mass spectrometry ; 1H,13C and 2D NMR
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A series of six tetrapeptides, analogues of AS-I phytotoxin, pathogenic to sunflower, have been synthesized either in solution and/or by solid phase methods and have been tested for phytotoxic activity in various plants and cytotoxic activity in three cancer cell lines. These peptides were identified as model compounds by fast atom bombardment (FAB), plasma desorption (PD), electrospray ionization (ESI) mass spectrometry and by1H,1H-1H,13C and1H-13C NMR. The data presented show that in protected tetrapeptides the molecular ion was easily identified whereas some difficulties appeared with the fully deprotected peptides. NMR spectra are given.
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  • 24
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Diclofenac ; Anti-phlogistics ; Non-proteinogenic amino acids ; Voltaren®. Thionation ; Cyclo-oxygenase inhibitors ; Ulcerogenic gastritis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In search for more potent, particularly less ulcerogenic gastritis that hopefully replace the universal NSAID “Diclofenac”, (2-[(2,6-di-chlorophenyl)amino]-phenylacetic acid, C.A.S. 15307-86-5), twelve new non-proteinogenic amino acid conjugates of the drug, namely that of sarcosine,β-alanine, D-leucine and D-phenylalanine, were synthesized and biologically screened for their anti-inflammatory, analgesic and ulcerogenic activity in rats. “Diclofenac” amino acid esters (IIa-d), were synthesizedvia the corresponding HOSu or HOBt active esters. Alkaline hydrolysis (NaOH) followed by acidification (KHSO4) or thioamide formation (Lawsson's Reagent, C.A.S. 19172-47-5), afforded the corresponding free acids IIIa-d or the thioamides IVa-d respectively. Interestingly, in contrary to the parent “Diclofenac”, the synthesized candidates (except IIId), were entirly nonulcerogenic in rats. Further, they considerably retained a generelized anti-phlogistic activity. The major “Diclofenac” irritating gastric side effect was thus eliminated. Particularly, the sarcosine conjugate IIa and its thiomimic IVa exhibit promising therapeutic perspectives.
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  • 25
    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.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 195-205 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Apis mellifera ; Drones ; Osmolarity ; Age dependency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the haemolymph of honeybee drones, concentrations of free amino acids were higher than in worker haemolymph, with different relative proportions of individual amino acids. The overall concentration of free amino acids reached its highest level at the 5th day after adult drone emergence, and after the 9th day only minor changes in the concentration and distribution of free amino acids were observed. This coincides with the age when drones reach sexual maturity and change their feeding behaviour. Levels of essential free amino acids were high during the first 3 days of life and thereafter decreased. Osmolarity was lowest at emergence (334 ± 41 mOsm), increased until the age of 3 days (423 ± 32mOsm) and then stayed generally constant until the 16th day of life. Only 25-day-old drones had significantly higher osmolarity (532 ± 38 mOsm). The overall change in osmolarity during a drone's lifetime was about 40%.
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  • 27
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Conformational constraint ; Cyclic disulfides ; -Cys-Cys-peptides ; Dipeptide mimetics ; Dithiols ; Glutathione analogues
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The glutathione analogue γ-(H-Glu-OH)- -OH (5), containing the 8-membered disulfide ring- replacing the native -Cys-Gly fragment, has been synthesized and characterized together with its reduced dithiol form γ-(H-Glu-OH)-Cys-Cys-OH (6).
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  • 28
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Polyamine catabolism ; Polyamine oxidase ; Diamine oxidase ; Testosterone ; Mouse kidney
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the present study developmental patterns of renal polyamineoxidizing enzymes polyamine oxidase (PAO) and diamine oxidase (DAO) in male and female ICR mice were demonstrated. The effects of testosterone (10μg/100g body weight) on renal PAO and DAO activities were also studied. The differences between sexes in both PAO and DAO activities were most clearly expressed in the immature kidney. At the age of 20 days PAO and DAO activities were 1.52 fold (p 〈 0.01) and 1.75 (p 〈 0.02) respectively higher in male mouse kidney than in female. Maturational processes reflected in significant increases in polyamine- oxidizing enzyme activities mainly in female mouse kidney, comparable with the gain in the kidney wet weight. Our data show that testosterone is able to influence renal PAO and DAO activities in addition to the well-known stimulation of polyamine biosynthesis. The hormonal effects were sex and age dependent. The influence of testosterone on renal PAO activity was mainly age dependent. The slight stimulation of renal PAO activity observed in 20- and 50-day old mice, 24h after testosterone administration, change with a decrease in the enzyme activity at the age of 70 days. The effects of testosterone on renal DAO activity were mainly sex dependent. Testosterone caused stimulation of DAO activity with a very close magnitude (nearly twice) in female mouse kidney, independently of the age of mice. In contrast, in male mice the hormone treatment resulted in a statistically significant increase in renal DAO activity at the age of 70 days (.1.3 fold, p 〈 0.05) only. It could be suggested that our data indicate the different contribution of renal PAO and DAO in androgen regulation of polyamine levels, depending on sex and the stage of the postnatal development.
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  • 29
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Allohydroxyproline ; Allothreonine ; Chiral separation ; Chirasil-Val ; Hydroxyproline ; Threonine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Experimental conditions for the derivatization and resolution by GLC of all stereoisomers of threonine and 4-hydroxyproline are reported. Threonine was in two steps converted toN,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl ester derivatives, the second of which was performed under anhydrous conditions. As such the enantiomers could pairwise be separated by capillary gas chromatography on a Chirasil-Val column. SinceL- andD-threonine eluted much earlier than the corresponding allo forms, quantitative determination of the allothreonine content inD- orL-threonine down to the one percent level could be simply accomplished but also enantiomeric impurities could be determined. Unlike for threonine, the corresponding 4-hydroxyproline isomers could not all be resolved asN,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl esters on this column. Although diastereomers could still be separated, the allo pair cochromatographed and the resolution for theL- andD-isomers was low. Complete separation of the 4-hydroxyproline isomers could be accomplished asN,O-bisprotected isobutyl amides, the formation of which required three derivatization steps. These were used for the determination of allohydroxyproline.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 323-334 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Taurine release ; Cerebellar granule cells ; Celldamaging conditions ; Glutamate receptors ; Veratridine ; Potassium stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The release of taurine from cultured cerebellar granule neurons was studied in different cell-damaging conditions, including hypoxia, hypoglycemia, ischemia, oxidative stress and in the presence of free radicals. The effects of both ionotropic and metabotropic glutamate receptor agonists on the release were likewise investigated. The release of [3H]taurine from the glutamatergic granule cells was increased by K+ (50mM) and veratridine (0.1 mM), the effect of veratridine being the greater. Hypoxia and ischemia produced an initial increase in release compared to normoxia but resulted in a diminished response to K. Hypoglycemia, oxidative stress and free radicals enhanced taurine release, and subsequent K− treatment exhibited a correspondingly greater stimulation. A common feature of taurine release in all the bove conditions was a slow response to the stimulus evoked by K+ and particularly to that evoked by veratridine. All ionotropic glutamate receptor agonists potentiated taurine release, but only the action of kainate seemed to be receptor-mediated. Metabotropic receptor agonists of group I slightly stimulated the release. The prolonged taurine release seen in both normoxia and cell-damaging conditions may be of importance in maintaining homeostasis in the cerebellum and reducing excitability for a longer period than other neuroprotective mechanisms.
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  • 31
    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.
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  • 32
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Protein ; arginine methyltransferase ; Inhibitors ; Ginseng extract ; Arginine derivatives ; Basic amino acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Protein-arginine N-methyltransferase (protein methylase I) catalyzes methylation of arginyl residues on substrate protein posttranslationally utilizing S-adenosyl-L-methionine as the methyl donor and yields NG-methylarginine residues. Arginyl-fructose and arginyl-fructosyl-glucose from Korean red ginseng were found to inhibit protein methylase I activity in vitro. This inhibitory activity was shown to be due to arginyl moiety in the molecules, rather than that of carbohydrates. Several basic amino acids as well as polyamines were also found to inhibit protein methylase I activity. Interestingly, the intensity of the inhibitory activity was correlated with the number of amino-group in polyamines, thus, in the order of spermine 〉 spermidine 〉 putrescine 〉 agmatine-sulfate, with IC50 at approximately 15 mM, 25 mM, 35 mM, and 50 mM, respectively. On the other hand, neutral amino acids or NaCI did not inhibit the enzyme activity. Lineweaver-Burk plot analysis of the protein methylase I activity in the presence of arginine and spermidine indicated that the inhibition was competitive in nature in respect to protein substrate, with the Ki values of 24.8 mM and 11.5 mM, respectively.
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  • 33
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Hexafluoroacetone ; α-N-Methylamino acids ; α-N-Phosphinoylmethylamino acids ; Pro-Glu-chimeras ; Pro-Tauchimeras
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A new method for the preparation of N-methylamino acids and some of their derivatives starting from hexafluoroacetone protected amino acids is described. The new concept results in saving of steps compared to conventional protection/activation techniques. Protection and deprotection proceed without racemization.
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  • 34
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Perfluorinated compounds ; Surfactants ; Complexing properties ; Carnosine ; β ; Amino acids ; Blood substitutes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The reaction of amines or sodium azide with 3-perfluoroalkyl-3-fluoroprop-2-enoate, followed by hydrogenation, affords perfluoroalkylatedβ-alanine analogues in very good yields. These compounds can be linked via an amide bond to produce peptide analogues such as carnosine or carcinine derivatives, which could have surfactive and complexing properties.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 16 (1999), S. 415-423 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; SOD-like activity ; Cu (III)-Poly-L-lysine ; Cu(III)-Poly-L-glutamic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The SOD-like activity of Cu(III) -complexes with polypeptides poly-L-lysine and poly-L-glutamic acid respectively was investigated. The Cu(II)-polypeptide complexes were first oxidized by K2IrCl6 to give the corresponding Cu(III) -compounds. The oxidation of Cu(II) and the corresponding Cu(II)/Cu(III) potential was evaluated by cyclic voltammetry (c.v.), UV-Vis and EPR spectroscopic (r.t.) experiments. Spin trapping EPR spectra were also conducted to confirm the formation of the superoxide radical. The SOD-like activity of each Cu(III)-complex was proved using the nitro blue tetrazolium (NBT) method slightly modified.
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  • 36
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Lysine ; Herbicides ; Azotobacter ; Xenobiotics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Production of lysine byAzotobacter chroococcum strain H23 was studied in chemically-defined media amended with different concentrations of alachlor, metolachlor, 2,4-D, 2,4,5-T and 2,3,6-TBA. The presence of 5, 10, and 50μg/ml of alachlor or 2,3,6-TBA significantly decreased quantitative production of lysine. However, the presence 2,4-D or 2,4,5-T at concentrations of 10 and 50μg/ml enhanced the production of lysine. Quantitative production of lysine was not affected as consequence of the addition of metolachlor to the culture medium, showing that the release lysine to the culture media byA. chroococcum was not affected by that herbicide.
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  • 37
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Trypanothione ; Glutathione ; Benzyloxycarbonyl-reductase ; Hydrocinnamoyl
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Kinetic data for alternative substrates of recombinant trypanothione reductase fromTrypanosoma cruzi were measured for a series ofN-substituted-L-cysteinylglycyl-3-dimethylaminopropylamides, in which the cysteineN-substituent was either a variant of the benzyloxycarbonyl group or was L-phenylalanine or L-tryptophan. Replacing the benzylic ether oxygen atom by CH2. or NH had relatively minor effects on kcat, but raised the value of Km, 4.5- and 10-fold, respectively. Similarly, relative to the carbobenzoxy group, anN-L-phenylalanyl orN-L-tryptophanyl replacement on the cysteine hardly altered kcat, but increased Km, values by 16.6 and 7.4 fold, respectively. These observations were consistent with the Km, values referring primarily to binding for this series of nonspecific substrates.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 243-255 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Serotonin receptor ; Serotonin-3 receptor ; Ion channel ; Ion permeability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Human 5-HT3 receptors expressed in HEK 293 cells were studied using patch-clamp techniques. The permeability ratios of cations to Na+ were Li+, 1.16; K+, 1.04; Rb+, 1.11; Cs+ 1.11; NMDG+, 0.04; Ca2+, 0.49, and Mg2+, 0.37. The permeability sequence of the alkali metal cations was Li+ 〉 Rb+ = Cs+ 〉 K+ 〉 Na+. Increased external concentrations of Ca2+ or Mg2+ decreased 5-HT-induced currents at all potentials tested in a voltage-independent manner. The single-channel conductance of human 5-HT3 receptors measured by fluctuation analysis of whole-cell currents was 790 ± 100fS. Differences in the basic properties of 5-HT3 receptors between species may explain interspecies differences in pharmacological properties.
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  • 39
    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.
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  • 40
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Tyrosine ; Phenylalanine ; Aromatic compounds ; Rumen microorganisms[/klw]
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Rumen contents from three fistulated Japanese native goats fed Lucerne hay cubes (Medicago sativa) and concentrate mixture were collected to prepare the suspensions of mixed rumen bacteria (B), mixed protozoa (P) and a combination of the two (BP). Microbial suspensions were anaerobically incubated at 39°C for 12h with or without 1 MM ofl-phenylalanine (Phe). Phe, tyrosine (Tyr) and other related compounds in both supernatant and microbial hydrolysates of the incubations were analyzed by HPLC. Tyr can be produced from Phe not only by rumen bacteria but also by rumen protozoa. The production of Tyr during 12h incubation in B (183.6 μmol/g MN) was 4.3 times higher than that in P. One of the intermediate products between Phe and Tyr seems to bep-hydroxyphenylacetic acid. The rate of the net degradation of Phe incubation in B (76.O μmol/g MN/h) was 2.4 times higher than in P. In the case of all rumen microorganisms, degraded Phe was mainly (〉53%) converted into phenylacetic acid. The production of benzoic acid was higher in P than in B suspensions. Small amount of phenylpyruvic acid was produced from Phe by both rumen bacteria and protozoa, but phenylpropionic acid and phenyllactic acid were produced only by rumen bacteria.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 357-368 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; o-Carboranylalanine ; Histidine ; Bacteria ; Fungi ; Oomycota ; Plasmopara
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Functionalized polyhedral carboranes, including amino acid analogs, have unique physicochemical properties and are used as experimental anticancer agents. However, our current knowledge on their effect in nonmammalian biological systems is limited. We investigated the activity spectrumin vitro ofo-carboranylalanine (o-Cba), considered to be a highly lipophilic analog of phenylalanine, against representative plant pathogenic bacteria and fungi of various taxonomic position. The antibacterial effect ofo-Cba against some species was comparable to that of the widely used agricultural antibiotic, streptomycin. The sensitivity of individual bacterial species too-Cba within the same genus varied to a greater extent than the average sensitivity of various genera. In general, this carborane-containing amino acid was more toxic to Gram positive bacteria (Bacillus, Corynebacterium, Curtobacterium, Micrococcus, Rhodococcus, and Staphylococcus) than to Gram negative ones (Agrobacterium, Erwinia, Escherichia, Pseudomonas, Rhizobium, and Xanthomonas). Compared to the commercial fungicide, prochloraz,o-Cba was weakly toxic against various fungi (Zygo- and Ascomycota). It was also inferior to the commercial fungicide metalaxyl in inhibiting the vegetative growth of oomyceteous plant pathogens (Pythium irregulare, Phytophthora cryptogea and Plasmopara halstedii). Against the asexual spores of P. halstedii,o-Cba, however, was over a thousandfold more active than tridemorph, a selective zoospore inhibitor fungicide. For all taxonomic groups, the observed antimicrobial effect ofo-Cba could be diminished with histidine, but not with phenylalanine. In studies on healthy and mildew-infected sunflower and tobacco plantso-Cba showed neither fungicidal nor phytotoxic effects at 500ppm. This is the first report on the biological activity spectrum of a carborane-containing amino acid.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Amino acids 17 (1999), S. 401-413 
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Indolylacrylic acid ; Tryptophan ; Indolylacryloylglycine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In addition to the main catabolic routes of tryptophan (Trp), there exist minor and less thoroughly investigated pathways; one of these leads to indolylacrylic acid (IAcrA). IAcrA is a plant growth hormone, whereas its biological role in animals is still obscure, as is the way and site where it is formed in the organism. A two-stage production is likely: Intestinal microorganisms catabolize Trp to indole derivatives which are then absorbed and converted to IAcrA and its glycine conjugate, indolylacryloylglyeine (IAcrGly). Our finding of IAcrGly in the urine of proven germ-free piglets points to the possibility that Trp can be converted to IAcrA without the intervention of intestinal microorganisms. Seasonal and age variations, influence of light and connection with photodermatoses have been reported. Besides other pathological conditions the differences in IAcrGly excretion relative to normal controls were especially pronounced in some myopathies, namely in boys with Duchenne muscular dystrophy.
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  • 43
    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.
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  • 44
    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.
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  • 45
    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.
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  • 46
    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.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 29 (1999), S. 257-261 
    ISSN: 1432-0789
    Schlagwort(e): Key words Alpine nitrogen cycle ; Amino acids ; Kobresia myosuroides ; Organic nitrogen ; Plant-microbe competition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract  Microbes are assumed to possess strong competitive advantages over plants for uptake of nutrients from the soil. The finding that non-mycorrhizal plants can obtain a significant fraction of their N requirement from soil amino acids contradicts this assumption. The amino acid glycine (Gly) has been used as a model amino acid in many recent studies. Our preliminary studies showed that Gly was a poor substrate for microbial growth compared to other amino acids. We tested the hypothesis that the alpine sedge Kobresia myosuroides competes better for Gly than for other amino acids because of decreased microbial demand for this compound. Soil microbial populations that could grow using Gly as a sole carbon source were about 5 times lower than those that could grow on glutamate (Glu). Gly supported a significantly lower population than any of the ten other amino acids tested except serine. In contrast, K. myosuroides took up Gly from hydroponic solution at faster rates than Glu. In plant-soil microcosms, plants competed with soil microbes 3.25 times better for Gly than for Glu. We conclude that the low microbial demand and the rapid plant uptake of Gly relative to other amino acids allow Gly to be an especially important nitrogen source for K. myosuroides.
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  • 48
    ISSN: 1432-0975
    Schlagwort(e): Key words Otolith ; Chemistry ; ICP-MS ; Stock discrimination ; Epinephelus striatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract  We examined the utility of otolith minor and trace element chemistry, assayed with inductively coupled plasma mass spectrometry (ICP-MS), as a means of delineating population structure in the Nassau grouper (Epinephelus striatus). We characterized the elemental composition of otoliths collected in 1993 from three locations in Exuma Sound, Bahamas and from Glover Reef, Belize in 1995. A single location in Exuma Sound was sampled in 1994 to test temporal variability in otolith composition. Five elements (Ca, Zn, Sr, Ba and Pb) were routinely detected, at levels significantly above background, by solution-based ICP-MS. Results from analysis of variance of elemental data, expressed as a ratio to Ca, indicated that there were no significant differences among the Exuma locations for any element, but significant variability was found between Glover Reef and the pooled Exuma localities for Zn/Ca, Sr/Ca and Ba/Ca ratios. Significant inter-annual differences at one Exuma Sound location was restricted to Ba/Ca ratios. Discriminant function analysis correctly classified 86% and 95% of the Belize and pooled Exuma sites, respectively. Otoliths from Belize were characterized by low Zn/Ca and high Ba/Ca and Pb/Ca ratios compared to otoliths from fish collected in Exuma Sound. Although differences in Ba levels may be related to upwelling at Glover Reef, more data are needed to definitely link otolith composition with regional differences in water chemistry.
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  • 49
    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.
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  • 50
    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.
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  • 51
    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.
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  • 52
    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.
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  • 53
    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.
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  • 54
    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.
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  • 55
    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.
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  • 56
    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.
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  • 57
    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.
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  • 58
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Hallervorden-Spatz-Krankheit (HSD) ; präsenile Demenz ; MRT ; paramagnetische Substanzen ; Globus pallidus ; Key words Hallervorden-Spatz-Disease (HSD) ; Early onset dementia ; MRI ; Paramagnetic substances ; Globus pallidus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary We report the history of a 38 year old patient who began to develop mental deterioration at the age of 26. After a time of 7 years neurological signs like writing dystonia occured. Hallervorden-Spatz-Desease (HSD) was diagnosed at the age of 36 in vivo with the clinical presentation of severe dystonia, rigidity, dementia, and typical signal loss in the globus-pallidus the reticular part of the substantia nigra, and the nucleus ruber in the T-2 weighted MRI. The „eye-of-the-tiger”-sign, a bilateral hyperintensity in the rostral globus pallidus, was not observed in follow-up examinations. HSD is a rare autosomal-recessive or sporadic disease of unknown etiology. In one third of the patients a dementing process is the first clinical sign of the disorder, and is a rare differential diagnosis of early onset dementia.
    Notizen: Zusammenfassung Wir berichten von einem 38jährigen Patienten, der im Alter von 26 Jahren eine progressive Demenz entwickelte. Erst nach einem Krankheitsverlauf von 7 Jahren kam es zur Manifestation eines rasch progredienten, dystonen Syndroms bis hin zur Immobilität im Alter von 36 Jahren. Die Diagnose der Hallervorden-Spatz-Erkrankung (HSD) wurde aufgrund des klinischen Bildes im Spätstadium der Erkrankung mit schwerster Demenz, Dystonie und Rigidität in Zusammenschau mit den typischen Signalauslöschungen in der T2-gewichteten MRT im Globus pallidus, dem Nucleus ruber und dem retikulären Anteil der Substantia nigra gestellt. Das „Eye-of-the-tiger”-Zeichen, eine bilaterale Signalhyperintensität im rostralen Anteil des Globus pallidus, wurde, auch bei Verlaufsuntersuchungen, nicht gefunden. Die Hallervorden-Spatz-Erkrankung ist ein autosomal-rezessiv oder sporadisch auftretendes Krankheitsbild ungeklärter Ätiologie. Da sich bei einem Drittel der Patienten mnestische Störungen im Kurz- und Langzeitgedächnis als Erstsymptom manifestieren, stellt die HSD eine seltene Differentialdiagnose eines präsenilen Demenzsyndroms dar. In der diagnostischen Beurteilung kommt der Magnetresonanztomographie eine wesentliche Bedeutung zu.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Der Nervenarzt 70 (1999), S. 276-280 
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Metachromatische Leukodystrophie ; Totschlag ; Hebephrenie ; MRT ; Diagnose ; Key words Metachromatic leukodystrophy ; Homicide ; Hebephrenia ; MRI ; Diagnosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary We report a patient with metachromatic leukodystrophy (MLD) with a first manifestation of homicide. On admission the patient showed a hebephrenia-like syndrom with inappropriate affect, thought disorder and behavioral changes. Magnetic resonance tomography (MRT) findings suggested a diagnosis of MLD, which was confirmed by a decreased activity of leucocyte arylsulfatase A and an excessive urinary sulfatide excretion.
    Notizen: Zusammenfassung Wir berichten von einem Patienten mit metachromatischer Leukodystrophie (MLD), der im Alter von 16 Jahren ein Kind tötete. Bei der klinischen Untersuchung zeigte er ein hebephrenes Syndrom mit veränderter Affektivität, formalen Denkstörungen und Verhaltensauffälligkeiten. Bei der neuropsychologischen Testung wurde eine starke Beeinträchtigung von Planen und Problemlösen bei insgesamt überdurchschnittlicher Intelligenz nachgewiesen. Die neurologischen und internistischen Befunde waren unauffällig. Anhaltspunkte für eine MLD fanden sich im Magnetresonanztomogramm (MRT) und wurden biochemisch bestätigt.
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  • 60
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Septum pellucidum ; Entwicklungs- störungen ; Zerebrale Fehlbildungen ; Schizophrenie ; Magnetresonanztomographie ; Key words Septum pellucidum ; Developmental disorder ; Cerebral malformations ; Schizophrenia ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Absence of the septum pellucidum is a rare developmental disorder of the human brain. Previous reports focused on the association with other cerebral anomalies. We present MRI scans showing an isolated absence of the septum pellucidum. The patient was suffering from a schizophrenic psychosis. Mental retardation or epileptic seizures, which are often found in more complex developmental brain disorders, were not observed. The septal area is part of the limbic system and aplasia of the septum pellucidum could indicate developmental anomalies of the limbic system. The concept of cerebral maldevelopment and the limbic system in schizophrenic psychosis is discussed.
    Notizen: Zusammenfassung Die isolierte Aplasie des Septum pellucidum gehört zu den seltenen dysplastischen Fehlbildungen des Gehirns. Während in älteren Arbeiten das Fehlen des Septum pellucidum meistens im Zusammenhang mit weiteren zerebralen Fehlbildungen berichtet wird, so zeigen neuere Untersuchungen doch häufiger auch isolierte Aplasien ohne weitere Fehlbildungen des Gehirns. Dabei scheint ein breites Spektrum der Fehlbildungen von komplexen Hirnfehlbildungen bis hin zur einfachen Aplasie des Septum pellucidum zu reichen. Kasuistisch wird über die Aplasie des Septum pellucidum bei einem Patienten berichtet, welche kernspintomographisch im Rahmen der routinemäßig durchgeführten bildgebenden Diagnostik gefunden wurde. Klinisch wurde bei dem Patienten eine hebephrene Psychose diagnostiziert. In der Ätiologie der schizophrenen Psychosen werden dysontongenetische Mechanismen diskutiert, v.a. Migrationsstörungen in limbischen Strukturen. Eine erhöhte Inzidenz von Anomalien des Septum pellucidum, v.a. Septum-pellucidum-Zysten ist von mehreren Autoren bei schizophrenen Patienten berichtet worden. Die Bedeutung des Septum pellucidum und des Septum verum als Bestandteile des limbischen Systems werden erörtert und eine mögliche Relevanz für das Konzept der dysontogenetischen Ätiologie schizophrener Psychosen wird diskutiert.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    International journal of legal medicine 112 (1999), S. 124-131 
    ISSN: 1437-1596
    Schlagwort(e): Key words Hydroxyproline ; D/L Aspartic acid ; N-TFA isopropyl ester derivatives ; Gas chromatography ; Collagen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Notizen: Abstract The proportion of D- to L-enantiomers of aspartic acid in metabolically isolated proteins has been used by forensic scientists to estimate age at death. We have demonstrated the interference of a derivative of hydroxyproline (N-TFA isopropyl Hyp ester) with the N-TFA isopropyl L-Aspartic (Asp) acid ester during gas chromatography of amino acids. This has serious implications for the accurate quantification of the D- to L-Asp ratio extracted from collagenous proteins. Having demonstrated the potential for this co-elution in amino acid standards, acid-soluble dentine proteins and non-mineralised collagen, we argue that this problem can be overcome either by high resolution separation or by analysis of the (Hyp-poor) non-collagenous protein fraction.
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  • 62
    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.
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  • 63
    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.
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  • 64
    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.
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  • 65
    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
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  • 66
    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.
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  • 67
    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
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  • 68
    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
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  • 69
    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.
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  • 70
    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
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 15 (1999), S. 287-289 
    ISSN: 1437-9813
    Schlagwort(e): Key words Soft-tissue tumor ; Myositis ossificans ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Two cases on myositis ossificans circumscripta (MOC) in the arm are reported. Plain X-ray films and magnetic resonance imaging (MRI) were performed in both cases. In the first, an intramuscular tumor-like mass without calcifications was found on MRI with soft-tissue edema extension. In the second, MRI disclosed additional bone-marrow edema. The diagnosis of MOC was confirmed by biopsy in one case and by follow-up in the other. MOC is a benign soft-tissue lesion that is rare in children, with an acute course and usually spontaneously favorable evolution. The differential diagnosis from an infection or a malignant tumor remains difficult. The best imaging modalities are conventional radiography and MRI. The MRI patterns of MOC are typical but not pathognomonic; typical MRI findings in conjunction with clinical symptoms during the early phase of MOC permit the postponement of a biopsy or aggressive surgical procedures. Surgery is indicated for cases not showing typical MOC calcifications at a later stage.
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  • 72
    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.
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  • 73
    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.
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  • 74
    ISSN: 1432-2161
    Schlagwort(e): Key words Hip joint ; Osteonecrosis ; MRI ; Bone scintigraphy ; Femoral head ; Transtrochanteric rotational osteotomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objective. To assess the ability of bone scintigraphy and magnetic resonance imaging (MRI) to predict the outcome of transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head (ONFH). Design. This study was a prospective evaluation of imaging techniques. Patients and methods. MRI and bone scintigraphy were performed on 20 hips in 18 patients at 3 months after TRO. The radiographic findings at 3 months after TRO, and the MRI and bone scintigraphic findings, were compared with the radiographic findings at final follow-up (mean 39 months). Results and conclusions. On MRI a low-intensity area or a low-intensity band in the new weight-bearing area extending over the acetabular edge on T1-weighted images was related to the presence of collapse on the radiographs at final follow-up. In hips with an area of absent activity in the new weight-bearing surface on bone scintigraphy, collapse was seen more frequently on radiographs at final follow-up than in hips without this feature. Bone scintigraphy was no more specific than radiography in predicting the outcome after TRO. We consider MRI to be superior to bone scintigraphy in predicting the occurrence of collapse, which is one of the major short-term problems after TRO.
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  • 75
    ISSN: 1432-2161
    Schlagwort(e): Key words Lipoma arborescens ; Synovial membrane ; MRI ; Shoulder ; Bursitis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A 44-year-old man presented with lipoma arborescens of the right shoulder, associated with a rotator cuff tear. MRI revealed villous proliferations with signal intensity of fat on all pulse sequences. At surgery, this bursa was found to contain moderately yellow cloudy fluid without fat globules. Histological examination of the lesion showed subsynovial accumulation of mature fat cells.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 298-304 
    ISSN: 1432-2161
    Schlagwort(e): Key words Osteosarcoma ; MRI ; Metastases ; skeletal muscle ; Soft tissue neoplasm
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Two cases of osteogenic sarcoma with skeletal muscle metastases are described. A 40-year-old woman presented with progressive swelling of both calves and a soft tissue back lump. She had been diagnosed with mandibular chondroblastic osteogenic sarcoma 6 years earlier. Radiographs showed calcified masses. MRI scans and bone scintigraphy revealed multiple soft tissue masses in both calves. Bone scintigraphy also showed uptake in the back lump, right thigh and left lung base. Biopsy confirmed metastatic chondroblastic osteogenic sarcoma, which initially responded well to chemotherapy. However, the metastatic disease subsequently progressed rapidly and she died 21 months after presentation. The second case concerns a 20-year-old man who presented with a pathologic fracture of the humerus, which was found to be due to osteoblastic osteogenic sarcoma. He developed cerebral metastases 17 months later, followed by metastases at other sites. Calcified masses were subsequently seen on radiographs of the abdomen and chest. CT scans confirmed the presence of densely calcified muscle metastases in the abdominal wall, erector spinae and gluteal muscles. The patient’s disease progressed rapidly and he died 30 months after presentation.
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 342-346 
    ISSN: 1432-2161
    Schlagwort(e): Key words Chordoma ; Notochordal rest ; MRI ; Vertebra
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Chordomas of the lumbar vertebral bodies are rare. We report an unusual case of an entirely intra-osseous chordoma of the fifth lumbar vertebra treated by vertebrectomy. Conventional radiographs and scintigraphy were normal. The lesion was well visualised by MR imaging, but showed only slight sclerosis on CT. We give our reasons for making a diagnosis of chordoma rather than giant notochordal rest and discuss the problems of management resulting from this diagnostic dilemma.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 347-349 
    ISSN: 1432-2161
    Schlagwort(e): Key words Plasmacytoma ; Plasmacytoma ; amyloid ; Plasmacytoma ; calcified ; Plasmacytoma ; extraosseous ; Plasmacytoma ; thorax ; Plasmacytoma ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  We report on a rare, calcified, plasma cell tumor of the spine causing progressive myelopathy. Other unusual features were the lack of an osseous lesion at the site of the mass, considerable calcified amyloid within the mass but no identifiable amyloid elsewhere, and normal serum immunoelectrophoresis.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 33-40 
    ISSN: 1432-2161
    Schlagwort(e): Key words Osteoblastoma ; Spine ; Radiography ; CT ; MRI ; Pathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objectives. To illustrate the CT and MRI features of spinal osteoblastomas and correlate the imaging with histological findings. Design. In a retrospective review the CT and MRI features of spinal osteoblastomas with respect to mineralisation, signal intensity (SI), adjacent reactive changes, enhancement following gadolinium-DTPA (5 cases) and adjacent soft tissue masses were compared and correlated with the histological findings including the degree of osteoid formation and matrix mineralisation, vascularity and surrounding reactive changes in bone and soft tissue. Patients. Eleven patients (7 males and 4 females; age range 8–43 years, mean age 19.5 years) with 12 osteoblastomas (1 patient suffered a recurrence) were studied. Results. All lesions showed classical features on CT with varying degrees of matrix mineralisation, whereas MRI identified mineralisation in only eight of 12 cases. MRI showed low signal intensity of the lesion on both T1- and T2-weighted sequences in several cases in the absence of heavy mineralisation. In these cases, histological examination revealed diffuse osteoid production by the tumour. All patients given gadolinium showed enhancement within the tumour on MRI. Reactive bone marrow changes were identified on MRI in 10 cases, and in five of these the changes were at multiple levels. An adjacent soft tissue mass was demonstrated in five cases, but extraosseous tumour was present histologically in only two of these. Conclusions. The MRI appearances of spinal osteoblastomas are varied and show no characteristic features. MRI may also overestimate the extent of the lesion due to extensive reactive changes and adjacent soft tissue masses. CT should continue to be the investigation of choice for the characterisation and local staging of suspected spinal osteoblastomas.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 49-51 
    ISSN: 1432-2161
    Schlagwort(e): Key words Cryptococcoma ; sacrum ; Cryptococcoma ; immunocompromised ; MRI ; sacrum ; CT ; sacrum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Cryptococcoma of the sacrum was the initial presentation of systemic cryptococcosis in a patient on chronic steroid therapy for autoimmune hepatitis. The bone lesion was the only overt manifestation of systemic cryptococcal disease, which preceded other clinical manifestations and led to the subsequent diagnosis of systemic infection.
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 545-560 
    ISSN: 1432-2161
    Schlagwort(e): Key words Trauma ; Joints ; injuries ; Joints ; radiography ; Joints ; MRI ; Cartilage ; Bones ; fractures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Fractures involving the articulating surfaces of bone are a common cause of chronic disability after joint injury. Acute fractures of the articular surface typically run parallel to the surface and are confined to the cartilage and/or the immediate subchondral cancellous bone. They should be distinguished from vertical or oblique bone fractures with intra-articular extension. This article reviews the mechanism of acute articular surface injuries, as well as their incidence, clinical presentation, radiologic appearance and treatment. A classification is presented based on direct inspection (arthroscopy) and imaging (especially MRI), emphasizing the distinction between lesions with intact (subchondral impaction and subchondral bone bruises) and disrupted (chondral, osteochondral lesions) cartilage. Hyaline cartilage, subchondral bone plate and subchondral cancellous bone are to be considered an anatomic unit. Subchondral articular surface lesions, osteochondral fractures and solely chondral fractures are different manifestations of impaction injuries that affect the articulating surface. Of the noninvasive imaging modalities, conventional radiography and MRI provide the most relevant information. The appropriate use of short tau inversion recovery, T1-weighted and T2-weighted (turbo) spin-echo as well as gradient-echo sequences, enables MRI to classify the various acute articular surface lesions with great accuracy and provides therapeutic guidance.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 658-660 
    ISSN: 1432-2161
    Schlagwort(e): Key words Medial collateral ligament ; tear ; interposition ; Knee ; MRI ; Posterolateral dislocation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Displacement of the medial collateral ligament (MCL) into the medial knee joint is an extremely rare finding associated with MCL tears, and is easily diagnosed on magnetic resonance imaging. A case of intra-articular interposition of the MCL during a severe knee injury is presented. A radiolucent ”fat stripe” sign and adjacent skin dimpling on radiographs may be relatively specific indicators of this injury.
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  • 83
    ISSN: 1432-2161
    Schlagwort(e): Key words Shoulder ; arthrography ; Shoulder ; comparative studies ; Shoulder ; injury ; Shoulder ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Purpose. In a patient with internal derangement of the shoulder, the diagnostic method of choice is controversial. Conventional arthrography can diagnose most rotator cuff tears accurately; however, in many institutions MR arthrography is usually necessary to diagnose labral tears. We utilized decision tree methodology to compare the cost- effectiveness of conventional arthrography and conventional MRI with a hypothetical algorithm in which a patient underwent arthrography, performed with admixed gadolinium, which if negative, was followed by MRI. Design. The use of double-contrast arthrography alone, conventional MRI alone, and gadolinium-enhanced MRI used as an adjunct to conventional arthrography were modeled for the diagnosis of full-thickness rotator cuff tears (RCT), partial RCTs, labral tears, and the absence of cuff/labral tears using decision analysis methodology. English language medical publications were searched to determine the base probabilities for the accuracy of the diagnostic tests. The outcome utilities ranged from –1 to +1 to reflect the value of correct diagnostic evaluation. Charges for diagnostic tests and appropriate surgical treatments were based on 1997 Medicare reimbursement rates for professional fees and hospital charges in an outpatient setting. Sensitivity analyses were performed to evaluate the effects of uncertainty regarding the prevalence of each disease state and the accuracy of several diagnostic tests. Results. In the base-case analysis, the average effectiveness of double-contrast arthrography alone, MRI alone and arthrography selectively followed by MRI were 0.6610, 0.6715, and 0.7204, respectively. The average costs for each of these strategies were $1090, $2033, and $2339, respectively. Conclusion. Arthrography performed with admixed diluted gadolinium, which if negative is immediately followed by MRI, was somewhat more expensive than conventional MRI. However, because of much greater effectiveness, cost-effectiveness was significantly higher for our proposed algorithm. Conventional arthrography without gadolinium, although less expensive, had severely limited effectiveness.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 61-74 
    ISSN: 1432-2161
    Schlagwort(e): Key words Ligament ; Ligament injury ; MRI ; Soft tissue injury ; Soft tissue trauma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Magnetic resonance imaging has had a dramatic effect on the means by which we diagnose ligament injuries. Tears resulting from either acute trauma or overuse can be detected noninvasively, directing appropriate therapy be it conservative or surgical. For the elite athlete, earlier diagnosis leads to earlier intervention, or alternatively, a normal MRI examination can result in an earlier return to play. While MRI is accepted for the diagnosis of certain injuries such as complete tears of the cruciate ligaments of the knee, other injuries, such as partial cruciate ligament tears or tears of the intercarpal ligaments of the wrist, remain controversial.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 717-722 
    ISSN: 1432-2161
    Schlagwort(e): Key words Sarcoid ; vertebrae ; Sarcoid ; rib ; Sarcoid ; calvarium ; Osteolytic ; CT ; MRI ; Surgical fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Skeletal sarcoidosis is rare. This report describes a 31-year-old African American man who presented with a destructive osteolytic lesion of C2 and another lesion in a rib. The lesion at C2 was treated with corpectomy and bone graft. Four months later the lesion recurred and a new lesion was discovered in the cervical vertebral column. The patient declined surgery for instability for another 3 months, choosing to remain in a halo. Seven months following the initial operation, a technetium bone scan showed spread of the disease to the calvarium and thoracic and lumbar vertebrae. The patient had no symptoms referable to these sites. The patient agreed to have his neck fused at this point. For the next 10 months, the patient was on steroids and a further new lesion appeared at L5 without localizing signs or symptoms. The patient declined further evaluation over the next 12 months and is now considered lost to follow-up.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 52-56 
    ISSN: 1432-2161
    Schlagwort(e): Key words Intraneural ganglion ; Peroneal nerve palsy ; Drop foot ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A case of peroneal nerve palsy caused by an intraneural ganglion is presented. The cystic mass was located posterolateral to the lateral femoral condyle and extended along the common peroneal nerve distal to the origin of the peroneus longus muscle. The nerve was compressed in the narrow fibro-osseous tunnel against the fibula neck and the tight origin of the peroneus longus muscle. The nerve was decompressed by complete tumor excision and transection of the origin of the peroneus longus muscle. Full recovery of nerve function was obtained in 6 months.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 594-598 
    ISSN: 1432-2161
    Schlagwort(e): Key words Osteochondroma ; Chondroma ; Extraskeletal tumor ; Soft tissue tumor ; Foot ; CT ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A case of pathologically proven extraskeletal osteochondroma is presented with magnetic resonance imaging (MRI), computed tomography (CT), bone scan and radiographic findings. The diagnosis of extraskeletal osteochondroma should be considered when a discrete, ossified mass is localized in the soft tissues of the distal extremities. Nomenclature surrounding this entity is controversial and is discussed.
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 616-620 
    ISSN: 1432-2161
    Schlagwort(e): Key words Joint ; MRI ; Infectious arthritis ; Septic joint ; Inflammation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objective. To differentiate the MR features of septic versus nonseptic inflamed joints. Design and patients. Thirty patients were referred for MRI with inflamed joints (19 were subsequently found to be septic and 11 nonseptic). At 1.5 T enhanced MRI five groups of signs related to joint space, synovium, cartilage, bone and peri-articular soft tissue respectively were assessed and compared between the septic and nonseptic groups. Results. The prevalence of MRI findings in septic versus nonseptic joints (respectively) was as follows: effusion (79% vs 82%), fluid outpouching (79% vs 73%), fluid heterogeneity (21% vs 27%), synovial thickening (68% vs 55%), synovial periedema (63% vs 55%), synovial enhancement (94% vs 88%), cartilage loss (53% vs 30%), bone erosions (79% vs 38%), bone erosions enhancement (77% vs 43%), bone marrow edema (74% vs 38%), bone marrow enhancement (67% vs 50%), soft tissue edema (63% vs 78%), soft tissue enhancement (67% vs 71%), periosteal edema (11% vs. 10%). The presence of bone erosions appeared to be an indicator for an infected joint (P=0.072); coexistence of bone marrow edema slightly improves the significance (0.068). A similar trend was obtained when combining bone erosions with either synovial thickening, synovial periedema, bone marrow enhancement or soft tissue edema (P=0.075). Conclusions. The combination of bone erosions with marrow edema is highly suggestive for a septic articulation; the additional coexistence of synovial thickening, synovial edema, soft tissue edema or bone marrow enhancement increases the above level of confidence. Similar to conventional radiography, the single sign that appeared to show a significant trend was the presence of bone erosions. However, no single sign or combination could either be considered pathognomonic or exclude the presence of a joint infection.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 655-657 
    ISSN: 1432-2161
    Schlagwort(e): Key words Acromegaly ; Locking ; Metacarpophalangeal joint ; Osteophyte ; Volar plate hypertrophy ; Radiography ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A 39-year-old man with acromegaly exhibited locking of metacarpophalangeal (MCP) joints of both index fingers. Large osteophytes were found at the metacarpal heads by radiography and computerized tomography (CT). Magnetic resonance (MR) images revealed hypertrophy of volar plates. We suggest that these characteristic acromegalic features caused locking of MCP joints. Surgery was required on one of the joints to release the locking.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Skeletal radiology 28 (1999), S. 703-709 
    ISSN: 1432-2161
    Schlagwort(e): Key words Proliferative myositis ; Childhood ; Lumbar muscles ; Ossification ; X-ray ; CT ; MRI ; PET
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A case of proliferative myositis in the lumbar paraspinal muscles in a 14-year-old boy is presented. Imaging investigations including plain radiograph, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), bone scan and positron emission tomography (PET) were suggestive of an inflammatory process such as myositis ossificans. The diagnosis was made by incisional biopsy. More pronounced edema, more muscle fiber necrosis and a higher cellularity were found compared to adult cases. The karyotype of the lesion was normal. Clinically, the mass disappeared spontaneously. After 24 months, asymptomatic bridging ossification between the third and fourth lumbar vertebrae was noted.
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  • 91
    ISSN: 1432-2161
    Schlagwort(e): Key words Shoulder ; Biceps tendon ; Anomaly ; Arthroscopy ; MRI
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A developmental anomaly of the long head of the biceps tendon was found in a cadaveric shoulder. Findings on arthroscopy, routine MR imaging, and MR arthrography were compared and correlated with results of anatomic dissection. MR arthrography appears to be a very good diagnostic imaging method for depicting this anomaly prior to arthroscopy.
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  • 92
    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.
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  • 93
    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.
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  • 94
    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.
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  • 95
    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.
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  • 96
    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.
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  • 97
    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
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  • 98
    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
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  • 99
    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
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  • 100
    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
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