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  • 2000-2004  (59)
  • 1960-1964  (3.699)
  • Inorganic Chemistry  (3.699)
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  • 1
    Digitale Medien
    Digitale Medien
    Heart valve dysfunction resulting from cellular rejection in a novel heterotopic transplantation rat model (2000)
    Springer
    Transplant international 13 (2000), S. S528 
    Details
    ISSN: 1432-2277
    Schlagwort(e): Key words Implantation model ; Aortic valves ; Valve dysfunction ; Rejection ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Structural failure of heart valve allografts may be related to technical factors or immunological reactions. To circumvent nonimmunological factors a new rat implantation model was developed to study whether alloreactivity results in histopathological changes and valve dysfunction. Syngeneic (WAG-WAG, DA-DA) and allogeneic (WAG-BN, WAG-DA) transplantation was carried out using this new technique, and the function of explanted valves was assessed 21 days later by retrograde comptence testing. Additionally, grafts were examined using standard histological and immunohistochemical techniques. There was no leakage during retrograde injection in nine of tem syngeneic and two of ten allogeneic grafts. Microscopically, syngeneic valves appeared normal without fibrosis or intimal thickening, although CD8+ lymphocytes and macrophages were found in necrotic myocardial rim and adventitia. In contrast, allogeneic valves were deformed and noncellular, with extensive infiltration of CD4+, CD8+ and CD68+ cells in adventitia and media. Absence of fibrosis and intimal thickening in syngeneic transplanted valves indicated circumvention of nonimmunological factors. Allogeneic valve transplantation induces cellular infiltration in the graft with subsequent graft failure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001470050395
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  • 2
    Digitale Medien
    Digitale Medien
    Hypoxia-reoxygenation differentially stimulates stress-activated protein kinases in primary-cultured rat hepatocytes (2000)
    Springer
    Transplant international 13 (2000), S. S597 
    Details
    ISSN: 1432-2277
    Schlagwort(e): Key words Hypoxia-reoxygenation ; JNK1/SAPK1 ; Rat ; Hepatocytes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Organ injury after ischemia and reperfusion (I/R) remains one of the most important limiting factors in liver surgery and transplantation. Oxygen-free radical (OFR) generation is considered a major cause of this damage. JNK1/SAPK1, a member of MAPK family, regulates cell adaptation to stressful conditions. The aim of this study was to determine if hypoxia-reoxygenation (H/R) can activate JNK1/SAPK1 and if OFR are involved in this activation. Primary cultured rat hepatocytes isolated from other liver cells and blood flow were submitted to warm and cold H/R phases mimicking surgical and transplant conditions. JNK1/SAPK1 was activated by both warm and cold H/R. Deferoxamine (1 mM), di-phenyleneiodonium (50 μM) and N-acetylcysteine (10 mM) significantly inhibited this kinase activation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001470050410
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  • 3
    Digitale Medien
    Digitale Medien
    Long-term small bowel allograft function induced by short-term FK 506 application is associated with split tolerance (2000)
    Springer
    Transplant international 13 (2000), S. S532 
    Details
    ISSN: 1432-2277
    Schlagwort(e): Key words Small bowel transplantation ; Split tolerance ; FK 506 ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Functional long-term allograft survival after experimental small bowel transplantation (SBT) is limited by chronic rejection. Initial application of high-dose FK 506 has been shown to induce stable long-term graft function. In order to examine whether this long-term function is associated with donor-specific tolerance, we analyzed the functional status of recipient T cells in vivo and in vitro. One-step orthotopic SBT was performed in the allogeneic Brown Norway (BN)-to-Lewis rat strain combination. FK 506 was given daily at a dose of 2 mg/kg from days 0–5 in the rejection model and from days 0–9 in the long-term functional model. Mean survival time in the rejection model was 98 ± 2.8 days. Histological examination of these small bowel allografts disclosed signs of chronic rejection. In contrast, all animals of the long-term functional model survived long term ( 〉 250 days) without clinical signs of chronic rejection. The latter model, furthermore, produced evidence of donor-specific tolerance. Whereas heterotopic Dark Agouti (DA) hearts were rejected regularly within 7 days, BN hearts survived indefinitely ( 〉 70 days). In vitro, mixed leukocyte reactivity of CD4 + T cells was similarly strong against donor (BN) antigens as against third-party (DA) antigens. The split tolerance revealed by our in vivo and in vitro results enabled acceptance of both the small bowel allograft without signs of chronic rejection and of donor-specific heart allografts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001470050396
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  • 4
    Digitale Medien
    Digitale Medien
    The T-type calcium channel blocker mibefradil reduced interstitial and perivascular fibrosis and improved hemodynamic parameters in myocardial infarction-induced cardiac failure in rats (2000)
    Springer
    Virchows Archiv 436 (2000), S. 147-157 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words T-type calcium channel blockade ; Mibefradil ; Myocardial infarction ; Cardiac remodeling ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Fibrillar collagen accumulates within the interstitium and around coronary arteries following cardiac failure and is responsible for abnormal myocardial stiffness and reduced coronary performance associated with impaired cardiac function. The aim of the study was to determine the effects of long-term treatment with the T-type calcium channel antagonist mibefradil on myocardial remodeling and cardiac function after chronic myocardial infarction (MI). MI was induced by permanent ligation of the left coronary artery in male Wistar rats. Animals were assigned to sham-operated, placebo-treated or mibefradil-treated (10 mg/kg per day p.o.) MI groups. Treatment with mibefradil was started either 7 days before, 24 h after, or 7 days after ligation and continued for 6 weeks after MI. At this time point, mean arterial blood pressure (MAP), heart rate (HR), left ventricular end-diastolic pressure (LVEDP) and cardiac contractility (dP/dtmax) were measured in conscious rats. Morphometric parameters were determined in picrosirius red-stained hearts: total heart weight (THW), interstitial and perivascular collagen volume fraction (ICVF, PCVF), myocardial infarct size (IS), vascular perimeter (VP), inner vascular diameter (IVD) and media thickness (MT). Six weeks after MI, MAP and dP/dtmax were decreased, and LVEDP was increased in placebo-treated animals. In mibefradil-treated animals whose treatment started 7 days before or 24 h after MI, MAP and dP/dtmax were higher, and LVEDP was lower than in placebo-treated controls. THW, ICVF, PCVF and MT were higher in placebo-treated animals. Mibefradil treatment resulted in higher ICVF and IS, higher VP and IVD (when started 7 days before MI) and lower PCVF and MT (when started 7 days before or 24 h after MI) than were observed in placebo-treated controls. Chronic treatment with mibefradil reduced interstitial and perivascular fibrosis and improved cardiac function in MI-induced heart failure in rats. Cardiac remodeling was best prevented when treatment was begun before the ischemic event.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00008215
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  • 5
    Digitale Medien
    Digitale Medien
    Induction of adenocarcinoma containing myoepithelial cells in rat submandibular gland by 7,12-dimethylbenz(a)anthracene (2000)
    Springer
    Virchows Archiv 437 (2000), S. 314-324 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Keywords 7 ; 12-dimethylbenz(a)anthracene ; Rat ; Submandibular gland ; Adenocarcinoma Myoepithelial cell
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In an attempt to induce adenocarcinoma containing myoepithelial cells (MECs) in the rat submandibular gland, we injected 7,12-dimethylbenz(a)anthracene (DMBA) dissolved in acetone into the glands of rat pups at the age of 10 days. In both male and female pups, the glands, including their developing terminal secretory units, contained far greater numbers of cells positive for proliferating cell nuclear antigen (PCNA) than did adult glands. A single administration of 1% DMBA (0.05 ml/130 g b.w.) did not produce adenocarcinoma, but did induce occasional sarcomas, such as rhabdomyosarcoma and fibrosarcoma, in 2 months. Most glands regenerated with minimal scar formation. Microscopically, these glands were atypical in that they contained increased numbers of PCNA-positive cells, underdeveloped granular ducts, and striated ducts surrounded by MECs positive for alpha smooth muscle actin (αSMA). Though these features were also observed in the regenerated glands after acetone injection, the number of PCNA-positive cells was relatively high in the glands of DMBA-treated females, especially in the terminal secretory unit. The second DMBA injection at 10 weeks of age produced adenocarcinoma made up of αSMA-positive MECs and keratin 19-positive duct cells. Such MEC-associated adenocarcinoma was induced in the glands of more than half the female but not the male animals. Replacement of either of the double DMBA treatments with acetone, or DMBA treatment, single or double, of adult glands did not produce adenocarcinoma, but did produce sarcoma and squamous cell carcinoma. These results suggest that (1) at least two genetic mutations are necessary for induction of adenocarcinoma with MECs in the rat submandibular gland, (2) the mutation is efficiently introduced to pup glands whose terminal secretory units exhibit extreme proliferative activity, and (3) the second mutation is difficult to introduce in male glands, whose proliferative activity is relatively low, and/or transformed cells need some female hormone after the mutation to propagate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280000223
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  • 6
    Digitale Medien
    Digitale Medien
    Effect of anti-CD4 monoclonal antibody administration on rat small bowel allograft survival and circulating leukocyte populations (2000)
    Springer
    Transplant international 13 (2000), S. 211-217 
    Details
    ISSN: 1432-2277
    Schlagwort(e): Key words Small bowel transplantation ; Monoclonal antibody ; Rat ; Rejection ; Flow cytometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study assessed the effect of an anti-rat CD4 monoclonal antibody (OX38) on heterotopic small bowel allograft rejection. Fully allogeneic small bowel transplants were performed in the PVG-to-DA-rat strain combination. Animals received either i) short course (days –1, 0 and 1) of 1 mg/kg per day OX38, ii) short course of 5 mg/kg per day or iii) extended course (days –2, –1, 0, 1, 2 and twice weekly thereafter) of 1 mg/kg per day. Both the high dose (13 days) and extended low-dose (12 days) courses prolonged graft survival compared to untreated control animals (7 days). The low-dose, short-course treatment had no effect. Similar regimens were given to animals that did not receive transplants and in which peripheral blood CD4+ cell counts fell to between 20 and 55 % of pretreatment levels and 20–30 % of binding sites were blocked. In summary, anti-CD4 monoclonal antibody therapy delayed rejection of rat small bowel allografts; however, long-term survival was not achieved.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001470050689
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  • 7
    Digitale Medien
    Digitale Medien
    Resistance to growth hormone and insulin-like growth factor-I in acidotic rats (2000)
    Springer
    Pediatric nephrology 14 (2000), S. 720-725 
    Details
    ISSN: 1432-198X
    Schlagwort(e): Key words Metabolic acidosis ; Growth ; Growth hormone ; Insulin-like growth factor-I ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Growth impairment induced by chronic metabolic acidosis is associated with an abnormal growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis. To examine the potentially beneficial effects of IGF-I on acidosis-induced growth impairment and the influence of GH and IGF-I treatment on the GH/IGF-I axis, three groups of acidotic young rats (untreated, AC, n=12; treated with recombinant human GH, GH, n=8; treated with recombinant human IGF-I, IGF-I, n=8) were studied, and compared with nonacidotic rats fed ad libitum (C, n=9)) or pair-fed with the AC group (PF, n=12). After 14 days of acidosis and 7 days of treatment, growth rate, hepatic abundance of 4.7-kilobase (kb) and 1.2-kb GH receptor transcripts and 7.5-kb and 1.8- to 0.8-kb IGF-I transcripts, serum GH-binding protein (GHBP), and IGF-I concentrations (mean±SEM) were analyzed. Significant decreases of 4.7-kb GH receptor [26±2 vs. 49±6 arbitrary densitometry units (ADU)] and 7.5 kb IGF-I (41±3 vs. 104±10 ADU) transcripts and low serum GHBP (25±1 vs. 32±1 ng/ml) and IGF-I (279±50 vs. 366±6 nmol/l) levels were found in the AC compared with the C rats. The majority of these alterations were also observed in PF rats. Compared with acidotic untreated rats, GH and IGF-I therapy produced no improvement in growth rate. GH treatment normalized the levels of IGF-I mRNA, aggravated the acidosis-related inhibition of the GH receptor gene, and did not modify the serum levels of GHBP and IGF-I. In contrast, IGF-I administration depressed the hepatic expression of all GH and IGF-I transcripts and normalized serum IGF-I concentrations. Our results confirm that sustained metabolic acidosis alters the GH/IGF-I axis, in part because of associated malnutrition, and induced growth retardation that is resistant to GH therapy. Our study also shows that administration of IGF-I does not accelerate the growth of acidotic rats, suggesting a peripheral mechanism, at the level of target tissues, is responsible for the resistance to the growth-promoting actions of GH and IGF-I.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00013425
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  • 8
    Digitale Medien
    Digitale Medien
    Apoptosis parallels ceramide content in the developing rat kidney (2000)
    Springer
    Pediatric nephrology 15 (2000), S. 188-191 
    Details
    ISSN: 1432-198X
    Schlagwort(e): Key words Apoptosis ; Ceramide ; Development ; Kidney ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Ceramide is emerging as an important hydrophobic sphingolipid involved in cell differentiation and apoptosis. Since apoptosis plays a significant role in cellular remodeling during renal morphogenesis, we measured ceramide content and apoptosis in the fetal (18 days gestation), neonatal (3, 7, and 14 days postnatal), and adult rat kidney. In addition, to determine whether developmental changes in ceramide content are tissue-specific, we compared renal ceramide content with that in lung and liver. Ceramide was measured by the diacylglycerol kinase assay, and apoptosis was determined by the TUNEL technique. Renal ceramide content fell over 100-fold from the fetus to the 7th postnatal day. Renal apoptosis paralleled ceramide content, with a greater than 300-fold decrease in apoptosis from fetal to adult life. Ceramide content of the lung and liver was significantly less than that of the kidney, and changed less with maturation. We conclude that maturational changes in ceramide content are tissue-specific, and that the high rate of apoptosis in the developing kidney may be related to the elevated ceramide content.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004670000444
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  • 9
    Digitale Medien
    Digitale Medien
    Myocardial enzyme activities in plasma after whole-heart irradiation in rats (2000)
    Springer
    Journal of cancer research and clinical oncology 126 (2000), S. 27-32 
    Details
    ISSN: 1432-1335
    Schlagwort(e): Key words Heart irradiation ; Plasma enzyme levels ; Myocardial enzyme levels ; Rat ; AbbreviationsCK creatine kinase ; LDH lactate de-hydrogenase ; AST aspartate aminotransferase ; ALT alanine aminotransferase ; α-HBDHα-hydroxybutyrate dehydrogenase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Plasma levels of myocardial enzymes present after local heart irradiation were studied in a rat model. The purpose was to investigate whether, within days after irradiation, these enzyme levels change to such an extent that they may be helpful in assessing the severity of cardiac damage after radiotherapy. Therefore, activities of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and α-hydroxybutyrate dehydrogenase (α-HBDH) were determined in the plasma and left ventricular myocardium of rats following local heart irradiation with a single dose of 20 Gy. A dose of 20 Gy is known to cause irreversible cardiac damage and to reduce survival times of the animals. Cardiac enzyme assays were performed directly after and twice daily for up to 2 weeks after radiation. Plasma CK, LDH, AST and α-HBDH levels were increased between 2 h and 24 h after irradiation. Plasma ALT levels remained unchanged. Myocardial enzyme levels, measured between 24 h and 16 days after radiation, did not differ between irradiated and control animals, although acute (first 12 h) reductions were observed in the irradiated group. The elevated enzyme levels in plasma appeared to correlate with the acutely reduced myocardial enzyme levels. Although irradiation with a dose of 20 Gy induced acute rises of cardiac enzyme levels in plasma, it is doubtful that fractionated radiation, as applied clinically for treatment of solid tumors, will induce plasma enzyme elevations that are large enough to indicate the extent of cardiac damage occurring acutely or chronically.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00008461
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  • 10
    Digitale Medien
    Digitale Medien
    The dynamic infusion test in rats (2000)
    Springer
    Child's nervous system 16 (2000), S. 451-456 
    Details
    ISSN: 1433-0350
    Schlagwort(e): Keywords Intracranial pressure ; CSF dynamics ; Infusion test ; Rat ; H-Tx rat ; Outflow resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Although the hydrocephalic H-Tx rat is a widely used model, data on the cerebrospinal fluid (CSF) dynamics in hydrocephalic rats are rare or – as the pressure volume index (PVI) – not available. We used hydrocephalic and nonhydrocephalic H-Tx rats, a stock with a high percentage of inherited hydrocephalus, for the evaluation of such data. In addition, a new, simple mathematical algorithm (”dynamic infusion test”), which has not formerly been used in animal experiments, was used as a pathophysiological model of CSF dynamics. Compared with classical methods for evaluation of these data, the dynamic infusion test gives a deeper insight into the relation between ICP and CSF dynamics. It was found that the resistance to outflow (ROF) in hydrocephalic rats was at least twice that in nonhydrocephalic rats. The PVI measured was similar in hydrocephalic and nonhydrocephalic animals, but clearly higher than the values reported in the literature. This may be attributable to the fact that the classically used bolus test, in contrast to the ”dynamic infusion test”, is representative only for the CSF compartment which is directly exposed to the bolus application.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00007290
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  • 11
    Digitale Medien
    Digitale Medien
    Maximum tolerated doses of methotrexate and 7-hydroxy-methotrexate in a model of acute toxicity in rats (2000)
    Springer
    Cancer chemotherapy and pharmacology 46 (2000), S. 69-73 
    Details
    ISSN: 1432-0843
    Schlagwort(e): Key words 7-Hydroxymethotrexate ; Methotrexate ; Maximum tolerated dose ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: After more than 50 years of methotrexate (MTX) treatment of acute lymphoblastic leukaemia (ALL), it is currently believed that as long as dose escalations are followed by adequate leucovorin rescue guided by monitoring MTX serum concentrations, hydration and urinary alkalinization, high-dose MTX (HD-MTX) can be tolerated without life-threatening toxicity. However, our recent experimental animal studies of the major metabolite of MTX, 7-OH-MTX, indicate that this concept may have some limitations. Animals with levels of 7-OH-MTX of 1 mM, which is below the levels routinely found in patients on HD-MTX, demonstrate intolerable toxicity and some animals die within 8 h. Electron microscopy indicates that endothelial cell and platelet functions are perturbed. Since animal data are lacking, and interspecies differences not known, we wanted to investigate the maximum tolerated doses of MTX and 7-OH-MTX in a rat model of short-term effects. The maximum tolerated dose was chosen instead of LD50 for reasons of animal welfare. Methods: We infused MTX and 7-OH-MTX into anaesthetized male Wistar rats and monitored the animals for 8 h. The drugs were given as a bolus plus continuous infusion. The dose-finding ranges were 1.8–11.3 g/kg MTX and 0.1–1.2 g/kg 7-OH-MTX. Results: The maximum tolerated dose was between 3 and 5 g/kg for MTX and lower than 0.1 g/kg for 7-OH-MTX. The mean serum concentrations of MTX and 7-OH-MTX in animals that did not survive the 8-h period were 21.9 and 1.6 mM, respectively. The animals that received the highest MTX or 7-OH-MTX doses and concentrations died after sudden reductions in heart rate and blood pressure. Conclusions: We demonstrated a lower maximum tolerated dose of 7-OH-MTX than of MTX in rats after 8 h. The 7-OH-MTX concentrations were in the therapeutic range after HD-MTX. If the rat/human interspecies differences are not large, our data may indicate that HD-MTX regimens should not be further dose intensified, due not so much to the effects of MTX as to those of 7-OH-MTX.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002800000111
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  • 12
    Digitale Medien
    Digitale Medien
    Changes in serum α2u-globulin levels in male rats given diethylstilbestrol and applicability to a screening test for endocrine-disrupting chemicals (2000)
    Springer
    Archives of toxicology 74 (2000), S. 48-53 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Key wordsα2u-Globulin ; Diethylstilbestrol ; Endocrine disrupter ; Rat ; Screening
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract α2u-Globulin (AUG) is a major rat urinary protein, which has a molecular weight of 16 kDa (kidney type) or 19 kDa (native type). The biosynthesis of this protein is under multi-hormonal regulation. In this study, we investigated changes in serum AUG level and their association with changes in the reproductive organs of male rats after the administration of the estrogenic chemical, diethylstilbestrol (DES) at doses ranging from 0.01 mg/kg per day to 100 mg/kg per day by gavage for 14 days. Our aim was to establish basic data for the development of a new screening method for endocrine disrupting chemicals based on serum AUG levels. DES treatment decreased the weight of testes in a dose-dependent manner; and was accompanied by atrophic histopathological changes in testes. Testis weights were significantly decreased by the group given 1 mg/kg per day DES; however, histopathological abnormalities were found in the group given 0.1 mg/kg per day DES. In four of five animals in the group given 1 mg/kg per day there was no significant decrease in testis weight and only a slight or moderate degeneration of the pachytene spermatocytes. Despite these findings, serum AUG levels in this group decreased markedly, while the serum AUG level markedly decreased even in the animals with no histopathological change in the 1 mg/kg per day or 0.1 mg/kg per day groups with no histopathological change also showed decreased serum AUG level. These results suggest that the serum AUG level may be a sensitive parameter for detecting the activity of estrogenic chemicals in intact male rats. Although a uterotropic assay has been proposed for immature female or ovariectomized female rats and is currently undergoing validation studies internationally, there is no screening method for estrogenic chemicals in intact male animals. More data on AUG changes by treatment with other estrogenic chemicals are needed in order to determine the sensitivity and specificity of this response to estrogens. Nonetheless, an AUG-based screening test for estrogenic chemicals may be useful owing to its applicability to conventional toxicity studies and an apparently higher sensitivity of this parameter compared to organ weight change or histology of testis in intact male rats and applicability to conventional toxicity studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002040050651
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  • 13
    Digitale Medien
    Digitale Medien
    Repeated dose (28 days) oral toxicity study of flutamide in rats, based on the draft protocol for the `Enhanced OECD Test Guideline 407' for screening for endocrine-disrupting chemicals (2000)
    Springer
    Archives of toxicology 74 (2000), S. 127-132 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Key words Flutamide ; Androgen antagonist ; Rat ; Enhanced OECD Test Guideline 407 ; Endocrine disrupters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In association with the international validation project to establish a test protocol for the `Enhanced OECD Test Guideline 407', we performed a preliminary 28-day, repeated-dose toxicity study of flutamide, a non-steroidal androgen antagonist, and assessed the sensitivity of a list of parameters for detecting endocrine-related effects of endocrine-disrupting chemicals (EDCs). Seven-week-old CD(SD)IGS rats were divided into four groups, each consisting of 10 males and 10 females, and administered flutamide once daily by oral gavage at doses of 0 (control), 0.25, 1 and 4 mg/kg body weight/day. Male rats were killed 1 day after the 28th administration. Female rats were killed on the day they entered the diestrus stage in the estrous cycle following the last treatment. Male rats receiving flutamide at dose levels of 1 and 4 mg/kg showed lobular atrophy of the mammary gland and a decrease in epididymal weight. In addition, 4 mg/kg flutamide-treated males exhibited raised serum testosterone and estradiol levels and decreased weight of the accessory sex glands. In females, a slight prolongation of the estrous cycle was also observed in the 4 mg/kg flutamide-treated group. No dose-related changes could be detected by haematology, serum biochemistry and sperm analysis. Thus, among the parameters tested in the present experimental system, the weight of endocrine-linked organs and their histopathological assessment, serum hormone levels, and estrous cycle stage allowed the detection of endocrine-related effects of flutamide.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002040050664
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  • 14
    Digitale Medien
    Digitale Medien
    Localization of endothelin receptors in bleomycin-induced pulmonary fibrosis in the rat (2000)
    Springer
    Histochemistry and cell biology 122 (2000), S. 507-517 
    Details
    ISSN: 1432-119X
    Schlagwort(e): Endothelin-A receptor ; Endothelin-B receptor ; Rat ; Pulmonary fibrosis ; Immunohistochemistry ; Quantitative PCR
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: AbstractPulmonary fibrosis is characterized by excessive extracellular matrix deposition with concomitant loss of gas exchange units, and endothelin-1 (ET-1) has been implicated in its pathogenesis. Increased levels of ET-1 from tissues and bronchoalveolar lavage have been reported in patients with pulmonary fibrosis and in animal models after intratracheal bleomycin. We characterized the cellular distribution of alveolar ET receptors by immunohistochemistry in bleomycin-induced pulmonary fibrosis in the rat and determined the regulation by bleomycin of ET receptor mRNA expression in isolated alveolar macrophages and rat lung fibroblasts. We found significant increases in the numbers of fibroblasts and macrophages at day 7 compared to day 28 and control animals. ETB receptor immunoreactivity was observed on fibroblasts and invading monocytes. Isolated fibroblasts expressed both ETA and ETB receptor mRNA, and ETA receptor mRNA was upregulated by bleomycin. Isolated resident alveolar macrophages expressed neither ETA nor ETB receptor mRNA which were also not induced by bleomycin. We conclude that, while ETB receptor stimulation of fibroblasts and monocytes recruited during bleomycin-induced lung injury exerts antagonistic effects on fibroblast collagen synthesis, the observed increase in the number of fibroblasts in vivo and upregulation of fibroblast ETA receptor mRNA by bleomycin in vitro point to a predominance of the profibrotic effects of ET receptor engagement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s00418-004-0708-7
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  • 15
    Digitale Medien
    Digitale Medien
    Constitutive NF-κB activity is modulated via neuron-astroglia interaction (2000)
    Springer
    Experimental brain research 130 (2000), S. 100-104 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Key words NF-κB ; p65 ; Hippocampal neurons ; Glia ; Astrocytes ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  NF-κB is found in many neuronal cell types in different states of activity. This study aimed to define which conditions induce constitutive NF-κB activity in cultured hippocampal neurons using activity-specific antibody staining. In co-culture with astroglia, hippocampal neurons were devoid of activated NF-κB. In these co-cultures, NF-κB could not be activated via kainate or glutamate. In contrast, separating neurons from the glial compartment resulted in a time-dependent increase of activated neuronal NF-κB. In this line, activation of NF-κB by kainate or glutamate is very effective in freshly separated cultures, but inhibited when the cultures are reassembled after stimulation. These findings suggests that a neuronal-glial interaction may regulate gene expression via NF-κB.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002210050011
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  • 16
    Digitale Medien
    Digitale Medien
    Changes of Fas and Fas ligand immunoreactivity after compression trauma to rat spinal cord (2000)
    Springer
    Acta neuropathologica 100 (2000), S. 75-81 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Fas ; Fas ligand ; Rat ; Spinal cord ; Trauma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This immunohistochemical study evaluated Fas and Fas ligand (FasL) in the rat nervous system and their changes in the spinal cord subjected to compression. Normal spinal cord showed a low level of Fas and FasL immunoreactivity in the white matter except in the corticospinal tracts. Fas and FasL immunoreactivity seemed to be located in axons and their myelin sheaths. Other regions of the nervous system did not show immunoreactivity to Fas and FasL. Moderate and severe compression injury of the spinal cord resulted in a reduction of Fas and FasL immunoreactivity in the white matter of injured T8–9 segments at 4 h and a complete loss at 1 day after trauma. This was seen even in the remaining white matter. In contrast, increased immunoreactivity to Fas and FasL was present in the cranial T7, caudal T10 (moderate injury) and T12 (severe injury) segments at day 4 with most intense staining were seen at day 9 after trauma. Increased Fas and FasL immunoreactivity may have pathophysiological implications for the development of secondary injuries after trauma to the spinal cord. Fas-FasL interactions may for instance be involved in apoptosis of oligodendrocytes which occurs as a delayed phenomenon after trauma to the spinal cord. The integrity of myelin sheaths may in this way be jeopardized by apoptosis of oligodendrocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051195
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  • 17
    Digitale Medien
    Digitale Medien
    Systemic hypothermia following spinal cord compression injury in the rat: an immunohistochemical study on MAP 2 with special reference to dendrite changes (2000)
    Springer
    Acta neuropathologica 100 (2000), S. 546-552 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Hypothermia ; Immunohistochemistry ; Microtubule-associated protein 2 (MAP2) ; Rat ; Spinal cord injury
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Systemic hypothermia has been shown to exert neuroprotective effects in experimental ischemic CNS models caused by vascular occlusions. The present study addresses the question as to whether systemic hypothermia has similar neuroprotective qualities following severe spinal cord compression trauma using microtubule-associated protein 2 (MAP2) immunohistochemistry combined with the avidin-biotin-peroxidase complex method as marker to identify neuronal and dendritic lesions. Fifteen rats were randomized into three equally sized groups. One group sustained thoracic laminectomy, the others severe spinal cord compression trauma of the T8-9 segment. The control group contained laminectomized animals submitted to a hypothermic procedure in which the esophageal temperature was reduced from 38 °C to 30 °C. The two trauma groups were either submitted to the same hypothermic procedure or kept normothermic during the corresponding time. All animals were sacrificed 24 h following the surgical procedure. The MAP2 immunostaining in the normothermic trauma group indicated marked reductions in MAP2 antigen in the cranial and caudal peri-injury zones (T7 and T10, respectively). This reduction was much less pronounced in the hypothermic trauma group. In fact, the MAP2 antigen was present in almost equally sized areas in both the hypothermic groups independent of previous laminectomy alone or the addition of trauma. Our study thus indicates that hypothermia has a neuroprotective effect on dendrites of rat spinal cords subjected to compression trauma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010000206
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  • 18
    Digitale Medien
    Digitale Medien
    Effects of cytomegalovirus infection and prolonged cold ischemia on chronic rejection of rat renal allografts (2000)
    Springer
    Transplant international 13 (2000), S. 54-63 
    Details
    ISSN: 1432-2277
    Schlagwort(e): Key words Kidney transplantation ; Rat ; Chronic rejection ; Cytomegalovirus ; Adhesion molecules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Previous studies have demonstrated that both cytomegalovirus (CMV) infection and prolonged cold ischemia of the allograft (CI) are associated with chronic rejection of renal transplants. The purpose of this study is to investigate the effect of CMV infection, of CI and of the combination of both, on the progression of chronic rejection, and to obtain a more detailed insight in their effects on the expression of adhesion molecules. Therefore, a rat transplantation model was used. Lewis recipients of renal allografts (with and without CI) from MHC-incompatible Brown Norway rats were inoculated with rat CMV or left uninfected. CMV infection alone resulted in an increased influx of CD4+ cells and macrophages early after infection, and in an increase in glomerular sclerosis and intima proliferation. CI caused an increase in infiltrating NK cells and an effect on intimal proliferation, glomerular sclerosis, and tubular atrophy. When CMV infection and CI were combined, an additive effect could be measured. This was however not the case for the function of the kidney. The creatinin showed a synergistic effect of the two influencing factors. Due to the CMV infection, an increase in CD49 d cells was detected. CI resulted in an increase in CD18 cells and an increase in the expression of CD62P on vessels, and CD54 and CD44 on tubules. When CMV infection and CI were combined, all the effects caused by CMV and CI alone were present in an additional way.¶The results of the present study suggest that special attention should be paid to the recipient of an ischemically injured graft when either the donor or the recipient is CMV-infected. The patterns seen in histology, the infiltration of leukocytes and the expression of adhesion molecules, suggest that CI and CMV infection both have an effect on rejection, but act by different mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001470050009
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  • 19
    Digitale Medien
    Digitale Medien
    Environmental modulation of the response to amphetamine: dissociation between changes in behavior and changes in dopamine and glutamate overflow in the rat striatal complex (2000)
    Springer
    Psychopharmacology 151 (2000), S. 166-174 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Keywords Novelty ; Context ; Environment ; Stress ; 6-OHDA ; Rotational behavior ; Striatum ; Nucleus accumbens shell ; Caudate ; Amphetamine ; Dopamine ; Glutamate ; Aspartate ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: We have previously shown that environmental novelty enhances the behavioral activating effects of amphetamine and amphetamine-induced expression of the immediate early gene c-fos in the striatal complex, particularly in the most caudal portion of the caudate. In contrast, we found no effect of novelty on the ability of amphetamine to induce dopamine (DA) overflow in the rostral caudate or in the core of the nucleus accumbens. Objectives: The twofold aim of the present study was to determine the effect of environmental novelty on (1) amphetamine-induced DA overflow in the shell of the nucleus accumbens and in the caudal portions of the caudate, and (2) glutamate and aspartate overflow in the caudal portions of the caudate. Methods: Two groups of rats with a unilateral 6-hydroxydopamine lesion of the mesostriatal dopaminergic system received amphetamine (0.5 mg/kg, i.v.) in physically identical cages. For one group, the cages were also the home environment, whereas, for the other group, they were a completely novel environment. In vivo microdialysis was used to estimate DA, glutamate, and aspartate concentrations. Results: Environmental novelty enhanced amphetamine-induced rotational behavior (experiments 1–3) but did not alter amphetamine-induced DA overflow in either the shell of the nucleus accumbens (experiment 1) or the caudate (experiment 2). In addition, the ability of environmental novelty to enhance amphetamine-induced behavioral activation was not associated with changes in glutamate or aspartate efflux in the caudate (experiment 3). Conclusions: The present data indicate that the psychomotor activating effects of amphetamine can be modulated by environmental context independent of its primary neuropharmacological actions in the striatal complex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002139900359
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  • 20
    Digitale Medien
    Digitale Medien
    Sensitization of amphetamine-induced wheel running suppression in rats: dose and context factors (2000)
    Springer
    Psychopharmacology 151 (2000), S. 219-225 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Keywords Amphetamine ; Wheel running ; Behavioral sensitization ; Pharmacological sensitization ; Novelty ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: This study explored whether repeated injections of amphetamine (AMP), which increase general locomotion, also increase acute wheel running, a highly structured, rewarding, motor behavior not correlated with other locomotor activities. Objectives: The experiments determine how 1–5 mg/kg d-AMP affects wheel running and see if, over repeated injections, the AMP effects show context specific sensitization. Methods: In experiment 1, 2 mg/kg AMP or saline (SAL) was injected on days 1, 3, 6, 8, and 10 to male Sprague-Dawley rats with either limited or no wheel experience. 20 min after the injection animals were tested in an open field for 5 min and then in a running wheel for 1 h. Rats were injected with SAL or AMP on the days following testing. On days 13 and 15, animals were tested for conditioning (following SAL) and sensitization (following AMP). In experiment 2, the effects on wheel running of repeated 1, 2, or 5 mg/kg AMP were tested. Results: In experiment 1, AMP (2 mg/kg) elevated open field ambulation but suppressed wheel running. Limited wheel experience potentiated the AMP-induced suppression. At test, the suppression of running was found to be context specific. In experiment 2, 1 mg/kg did not affect running, while 2 and 5 mg/kg resulted in dose-dependent running suppression. Acquisition and test AMP dose both influenced the running suppression at test; context had a marginal influence. Conclusions: The degree of running suppression induced by repeated AMP is determined by both psychological (the injection context) and pharmacological (the acquisition dose) factors. This AMP-induced running suppression is consistent with the sensitization of stereotyped behavior.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130000446
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  • 21
    Digitale Medien
    Digitale Medien
    Effects of the competitive nicotinic antagonist erysodine on behavior occasioned or maintained by nicotine: comparison with mecamylamine (2000)
    Springer
    Psychopharmacology 148 (2000), S. 234-242 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Nicotine ; Drug discrimination ; Self-administration ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: The cellular effects of nicotine underlying its addictive liability are thought to be mediated by neuronal nicotinic receptors (nACHRs) in the central nervous system. It is believed that densely expressed β2-containing nACHRs in the central nervous system are responsible for these actions, but few data are available that can directly assess subtype mediation of nicotine’s acute subjective and reinforcing effects. Objective: The present study compared the effects of the competitive nACHR antagonist erysodine and the noncompetitive antagonist mecamylamine in rats trained to discriminate or self-administer nicotine. Methods: Adult male rats were trained to disciminate 0.4-mg/kg injections of nicotine from vehicle in a two-lever procedure of food-maintained behavior, or to self-administer 0.03-mg/kg injections of nicotine under fixed-ratio 5 or progressive-ratio schedules of reinforcement. Additional rats were trained under a food-maintained procedure of lever pressing. Results: Erysodine (0.3–10 mg/kg) and mecamylamine (0.1–1.0 mg/kg) blocked nicotine discrimination, although only erysodine produced the rightward shift that would be predicted of a competitive antagonist. Erysodine (0.32–32 mg/kg) and mecamylamine (0.32–3.2 mg/kg) also selectively reduced nicotine self-administration on a fixed-ratio schedule and lowered break points on a progressive-ratio schedule. Conclusions: Based on the known affinity of erysodine for α4β2 nACHRs and its selectivity relative to α7 and α1β1γδ receptors, the present data support a critical role of β2-containing nACHR constructs in the discriminative and reinforcing actions of nicotine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050047
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  • 22
    Digitale Medien
    Digitale Medien
    The discriminative stimulus properties of the atypical antipsychotic olanzapine in rats (2000)
    Springer
    Psychopharmacology 148 (2000), S. 224-233 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Drug discrimination ; Olanzapine ; Clozapine ; Chlorpromazine ; Haloperidol ; Thioridazine ; Raclopride ; Risperidone ; Scopolamine ; Ritanserin ; Atypical antipsychotic ; Neuroleptic ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Analysis of the preclinical behavioral effects of atypical antipsychotic agents will provide a better understanding of how they differ from typical antipsychotics and aid in the development of future atypical antipsychotic drugs. Objectives: The present study was designed to provide information about the discriminative stimulus properties of the atypical antipsychotic olanzapine. Methods: Rats were trained to discriminate the atypical antipsychotic olanzapine (either 0.5 mg/kg OLZ or 0.25 mg/kg OLZ, i.p.) from vehicle in a two- lever drug discrimination procedure. The atypical antipsychotic clozapine fully substituted for olanzapine in both the 0.5-mg/kg OLZ group (99.3% drug lever responding [DLR]) and the 0.25-mg/kg OLZ group (99.9% DLR). The typical antipsychotic chlorpromazine also substituted for olanzapine in both the 0.5-mg/kg OLZ group (87.5% DLR) and in the 0.25-mg/kg OLZ group (98.9% DLR); whereas, haloperidol displayed partial substitution for olanzapine in the 0.5-mg/kg OLZ group (56.1% DLR) and in the 0.25-mg/kg OLZ group (76.4% DLR). The 5.0-mg/kg dose of thioridazine produced olanzapine-appropriate responding in the 0.5-mg/kg OLZ group (99.6% DLR), but only partial substitution was seen with the 0.25-mg/kg OLZ training dose (64.0% DLR). The atypical antipsychotics raclopride (53.9% DLR) and risperidone (60.1% DLR) displayed only partial substitution in the 0.5-mg/kg OLZ group. Both the muscarinic cholinergic antagonist scopolamine (90.0% DLR) and the 5-HT2A/2C serotonergic antagonist ritanserin (86.0% DLR) fully substituted for olanzapine in the 0.5-mg/kg OLZ group. Conclusions: In contrast to previous discrimination studies with clozapine-trained rats, the typical antipsychotic agents chlorpromazine and thioridazine and the serotonin antagonist ritanserin substituted for olanzapine. These results demonstrate that there are differences in the mechanisms underlying the discriminative stimulus properties of clozapine and olanzapine. Specifically, olanzapine’s discriminative stimulus properties appear to be meditated in part by both cholinergic and serotonergic mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050046
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  • 23
    Digitale Medien
    Digitale Medien
    The role of nicotinic and muscarinic acetylcholine receptors in attention (2000)
    Springer
    Psychopharmacology 148 (2000), S. 243-250 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Attention ; Scopolamine ; Mecamylamine ; Oxotremorine ; Physostigmine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: This study tried to determine the relative roles of muscarinic and nicotinic cholinergic receptors in attentional processing. Methods: The effects of cholinoceptor agonists and antagonists, and of an anticholinesterase, were studied on performance of rats in a five-choice serial reaction time task. Results: Scopolamine (0.1 mg/kg) and mecamylamine (5.0 mg/kg) produced deficits in accuracy and reaction time, respectively. This may suggest a differential role for the two types of cholinoceptors in information processing. Combinations of sub-threshold doses of scopolamine (0.01–0.03 mg/kg) and mecamylamine (0.5–1.6 mg/kg), which alone did not affect accuracy or reaction time, did not produce significant deficits in attention. However, the pattern of effects after combined treatment suggested that the differential deficits seen with these drugs alone remained. The anticholinesterase physostigmine (0.1 mg/kg) and the non- selective muscarinic agonist oxotremorine (0.03 mg/kg) induced severe behavioural disruption at doses that appeared to be relatively well tolerated in previous studies; this precluded the derivation of accuracy and response time data at these doses. At lower doses, neither physostigmine (0.05 mg/kg) nor oxotremorine (0.003 mg/kg) significantly affected any performance measure; this may reflect the ability of both drugs to indirectly or directly activate presynaptic muscarinic receptors that inhibit acetylcholine release, respectively. Conclusions: Both muscarinic and nicotinic cholinoceptors may be important in attention but they may serve different roles in information processing; this hypothesis could be tested using tasks that place different emphasis on different stages of information processing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050048
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  • 24
    Digitale Medien
    Digitale Medien
    Diazepam-like effects of a fish protein hydrolysate (Gabolysat PC60) on stress responsiveness of the rat pituitary-adrenal system and sympathoadrenal activity (2000)
    Springer
    Psychopharmacology 149 (2000), S. 34-40 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words ACTH ; Corticosterone ; GABA ; Noradrenaline ; Adrenaline ; Stress ; Rat ; Diazepam
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Gabolysat PC60 is a fish protein hydrolysate with anxiolytic properties commonly used as a nutritional supplement. Objective: The diazepam-like effects of PC60 on stress responsiveness of the rat pituitary-adrenal system and on sympathoadrenal activity were studied. Methods: The activity of the pituitary-adrenal axis, measured by plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone (B) of the sympathoadrenal complex, measured by circulating levels of noradrenaline (NA) and adrenaline (A), and the gamma aminobutyric acid (GABA) content in the hippocampus and the hypothalamus were investigated in male rats which received daily, by an intragastric feeding tube, for 5 days running either diazepam (1 mg/kg) or PC60 (300 or 1200 mg/kg). Controls received only solvent (carboxymethylcellulose 1%). Six hours after the last force-feeding, the rats were subjected to 3 min ether inhalation or 30 min restraint and killed by decapitation 30 min after ether stress or at the end of restraint. Results: Baseline plasma levels of ACTH, B, NA and A were not affected by either diazepam or PC60. Both ether- and restraint-induced release of ACTH, but not B, were similarly and drastically reduced by diazepam and PC60 (1200 mg/kg). Both diazepam and PC60 (1200 mg/kg) deleted restraint-induced NA and A increases. Both treatments also reduced the ether-induced rise of A. Basal levels of GABA were significantly increased in both the hippocampus and the hypothalamus in PC60-treated rats and only in the hippocampus in diazepam-treated ones. In controls, ether inhalation as well as restraint increased GABA content of these two brain structures. In contrast, such stress procedures performed in PC60-treated rats reduced GABA content slightly in the hippocampus but significantly in the hypothalamus. In diazepam-treated rats, GABA content of the hypothalamus was unaffected by stresses but that of the hippocampus was slightly decreased. Conclusions: Present data suggest diazepam-like effects of PC60 on stress responsiveness of the rat pituitary adrenal axis and the sympathoadrenal activity as well as GABA content of the hippocampus and the hypothalamus under resting and stress conditions. These effects of PC60 agree with anxiolytic properties of this nutritional supplement, previously reported in both rats and humans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002139900338
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  • 25
    Digitale Medien
    Digitale Medien
    Acute exposure to saccharin reduces morphine analgesia in the rat: evidence for involvement of N-methyl-d-aspartate and peripheral opioid receptors (2000)
    Springer
    Psychopharmacology 149 (2000), S. 56-62 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Morphine ; Opioid receptor ; NMDA ; Tolerance ; Rat ; Tail flick
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Pairings of a sweet taste and injection of morphine result in a learned avoidance of that taste and learned analgesic tolerance. This avoidance is mediated by the drug’s peripheral effect, while learned tolerance involves activation of N-methyl-d-aspartate (NMDA) receptors. Exposure to a sweet taste also reduces morphine analgesia. We studied whether this taste-mediated reduction was reversed by an NMDA or peripheral opioid receptor antagonist. Objectives: To determine whether an intraoral infusion of saccharin would modulate morphine analgesia in rats, and to study the contribution of NMDA as well as peripheral opioid receptors to this modulation. Methods: Six experiments used the rat’s tail-flick response to study the effect of an intraoral infusion of a sodium saccharin solution on morphine analgesia, and the effects of the quaternary opioid receptor antagonist methylnaltrexone as well as the non-competitive NMDA receptor antagonist MK-801 on this modulation of analgesia. Results: An intraoral infusion of saccharin reduced the analgesic effects of an intraperitoneal (i.p.) injection of morphine across a range of doses (experiment 1a), which was not attributable to an influence on tail-skin temperature (experiment 1b). This reduction was mediated by opioid receptors in the periphery and activation of NMDA receptors because morphine analgesia was reinstated by an i.p. injection of either methylnaltrexone (experiment 2a) or MK-801 (experiment 3a), which was not due to the effect of methylnaltrexone (experiment 2b) or MK-801 (experiment 3b) on morphine analgesia in the absence of saccharin. Conclusions: These results document evidence for an antagonism of morphine analgesia by actions of the drug at peripheral opioid receptors and excitatory amino-acid activity at NMDA receptors. They are discussed with reference to the aversive motivational effects of peripheral opioid receptors and pain facilitatory circuits.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002139900337
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  • 26
    Digitale Medien
    Digitale Medien
    Sex differences in the discriminative stimulus effects of m-chlorophenylpiperazine and ethanol withdrawal (2000)
    Springer
    Psychopharmacology 149 (2000), S. 170-175 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words  m-Chlorophenylpiperazine ; Drug discrimination ; Ethanol withdrawal ; Anxiety ; 17β-estradiol ; Sex difference ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: The serotonergic system plays a role in regulation of anxiety and ethanol withdrawal (EW). Nevertheless, few studies have assessed sex differences in serotonergic effects on EW. Objectives: This study examined sex differences in the anxiogenic stimu-li induced by a serotonin (5-HT)1b/2 agonist, meta- chlorophenylpiperazine (mCPP), prior to ethanol and during EW. Methods: Gonadectomized or sham-operated adult male and female rats and 17β-estradiol (2.5 mg, 21-day release, s.c.) -replaced ovariectomized (OVX) rats were trained to discriminate mCPP (1.2 mg/kg, i.p.) from saline in a two-lever choice task for food. Latency to the first lever press and mCPP lever selection were measured following mCPP (0–1.2 mg/kg). Rats then received chronic ethanol-containing liquid diet (6.5%) for 10 days and were tested for mCPP lever selection 12 h and 36 h after removal of ethanol. Results: Fewer sham female and β-estradiol-replaced OVX rats selected the mCPP lever than male or OVX rats, and showed an increased initiation latency after mCPP injection. During EW (12 h and 36 h), fewer sham female and β-estradiol-replaced OVX rats responded on the mCPP-lever after saline injection as well as after mCPP challenge than male or OVX rats. Castration did not alter any response of male rats to mCPP. Conclusions: (1) mCPP discrimination is a useful measure of EW in male and female rats; and (2) sham female and β-estradiol-replaced OVX rats are less sensitive to the discriminative stimulus prior to and during EW, but more sensitive to impaired behavioral initiation induced by mCPP than male or OVX rats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002139900353
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  • 27
    Digitale Medien
    Digitale Medien
    Role of dopamine in prepulse inhibition of acoustic startle (2000)
    Springer
    Psychopharmacology 149 (2000), S. 181-188 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Acoustic startle response ; Prepulse inhibition ; Sensorimotor gating ; Schizophrenia ; Dopamine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Prepulse inhibition of acoustic startle is the reduction in startle response to an intense auditory stimulus when this stimulus is immediately preceded by a weaker prestimulus. Prepulse inhibition occurs normally in humans and experimental animals, but schizophrenic persons often exhibit a marked impairment in this measure. Previous studies have shown that dopamine (DA)-dependent neuronal mechanisms are involved in the modulation of prepulse inhibition. Objective: Experiments were conducted in rats to elucidate further the involvement of DA-ergic mechanisms in prepulse inhibition. Results: In line with previous studies, the indirect DA agonist, amphetamine, was shown to decrease prepulse inhibition. A close reverse relationship over time between DA overflow in the nucleus accumbens and prepulse inhibition was obtained using a technique allowing concomitant measurement of these parameters in awake, freely moving rats. This effect was more pronounced in amphetamine-treated rats compared to rats treated with equimolar doses of cocaine, which increased DA overflow without affecting prepulse inhibition. In other experiments, the combined treatment with subthreshold doses of the selective DA D1 agonist, SKF 38393, and the selective DA D2 agonist, quinpirole, was also shown to decrease prepulse inhibition. Finally, the selective DA D2 antagonist, raclopride, was shown to enhance prepulse inhibition. Conclusions: In line with previous studies, it is concluded that DA neurotransmission is involved in the modulation of prepulse inhibition and that the ventral part of the mesostriatal DA system may serve an important role in this modulation. Furthermore, the possibility is discussed that the discrepant results on prepulse inhibition obtained with amphetamine and cocaine may disclose functionally relevant differences in their mechanisms of action, and that the enhancement of prepulse inhibition induced by some antipsychotics in rats may reflect their propensity to induce adverse mental effects in humans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130000369
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  • 28
    Digitale Medien
    Digitale Medien
    The 5-HT1A receptor agonist 8-OH-DPAT reduces rats’ accuracy of attentional performance and enhances impulsive responding in a five-choice serial reaction time task: role of presynaptic 5-HT1A receptors (2000)
    Springer
    Psychopharmacology 149 (2000), S. 259-268 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words 8-OH-DPAT ; WAY 100635 ; 5 ; 7-Dihydroxytryptamine ; Attention ; Impulsivity ; Pre- and postsynaptic 5-HT1A receptor ; Dorsal raphe ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Whilst several studies have investigated the role of serotonergic receptor subtypes in learning and memory, relatively few studies have examined their role in attentional processes. Objective: The present study investigated the role of pre- and postsynaptic 5-HT1A receptors on rats’ attentional performance in the five-choice serial reaction time task (5-CSRT). Methods: Hungry rats were trained in the 5-CSRT task to detect brief (0.5 s) flashes of light presented randomly in one of five locations with a fixed intertrial interval of 5 s paced by the rat. We studied the effects of 8-OH-DPAT, a 5-HT1A receptor agonist, at various subcutaneous (SC) doses (10–100 µg/kg) on measures of rats’ discriminative accuracy (the index of attentional functioning) and various behavioural indices of response control and motivation. Manipulations of basic task parameters, intracerebroventricular (ICV) injections of 5,7-dihydroxytryptamine (5,7-DHT) to deplete forebrain 5-HT and treatments with a selective 5-HT1A receptor antagonist WAY 100635 were made in order to determine the behavioural and neural specificity of the effects of 8-OH-DPAT. Results: A dose of 100 µg/kg, but not lower doses, significantly reduced choice accuracy and increased errors of omission, latencies to respond correctly and to collect food reward and premature responses. All these effects were completely blocked by WAY 100635, injected SC 5 min before 8-OH-DPAT at doses from 10–100 µg/kg. WAY 100635 by itself had no effect in the task. Dimming the visual stimuli to one-third of the usual brightness did not modify the effect of 8-OH-DPAT on choice accuracy. Prolonging the stimuli from 0.5 to 1.0 s reversed 8-OH-DPAT’s effect on choice accuracy but did not modify the other effects on rats’ performance. An ICV injection of 150 µg 5,7-DHT, which depleted forebrain serotonin by 90%, reversed 8-OH-DPAT’s effect on choice accuracy but did not modify the effects on errors of omission and latency to make correct responses. Similar effects were found by infusing 1.0 µg/0.5 µl WAY 100635 in the dorsal raphe 5 min before 8-OH-DPAT. 8-OH-DPAT increased the latency to collect the reinforcement; this effect was attenuated by ICV 5,7-DHT and completely antagonized by WAY 100635 in the dorsal raphe. Rats treated with 5,7-DHT or 8-OH-DPAT showed more premature responses and these effects were markedly reduced by the combined treatment. Conclusions: The results suggest that stimulation of presynaptic 5-HT1A receptors is involved in the ability of 8-OH-DPAT to cause attentional dysfunction and enhance impulsivity while slowing of responding and increase in errors of omission mainly depend on stimulation of postsynaptic 5-HT1A receptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002139900368
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  • 29
    Digitale Medien
    Digitale Medien
    Prefrontal dopamine is directly involved in the anxiogenic interoceptive cue of pentylenetetrazol but not in the interoceptive cue of chlordiazepoxide in the rat (2000)
    Springer
    Psychopharmacology 149 (2000), S. 366-376 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Prefrontal cortex ; Dopamine ; Anxiety ; Drug discrimination ; Pentylenetetrazol ; Chlordiazepoxide ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: The prefrontal cortical (PFC) dopamine (DA) system has been implicated in anxiety-related behavioral changes, but direct, unequivocal support for this idea is sparse. Objectives: The present aim was to study the functional significance of prefrontal DA using the pentylenetetrazol (PTZ) discrimination model of anxiety. A comparison was made with its role in the cue of the anxiolytic drug chlordiazepoxide (CDP). Methods: Two groups of rats were trained to discriminate either PTZ (20 mg/kg, s.c.) or CDP (10 mg/kg, i.p.) from saline using an operant drug discrimination procedure. After prolonged training, half of each group was used to assess biochemical changes induced by both drugs in different sub areas of the PFC. For the remaining rats, discrimination training continued and generalization tests with PTZ and CDP were performed. Rats were then provided with bilateral guide cannulae aimed at the ventromedial (vm) PFC, and the effects of local infusions of DAergic drugs on discriminative performance were evaluated. Results: CDP did not affect PFC DA activity, but PTZ increased the DOPAC/DA ratio in the vmPFC selectively. Generalization tests showed that the cues of PTZ and CDP were dose dependent. In PTZ-trained rats, infusions of the DA receptor antagonist cis-flupenthixol into the vmPFC blocked the PTZ cue dose dependently, whereas the agonist apomorphine partially generalized to this cue. In CDP-trained rats, neither drug antagonized or generalized to the CDP cue, showing that PFC DA is not critically involved in the CDP cue and that local pharmacological manipulations of PFC DA do not affect discriminative abilities per se. Conclusions: The DAergic innervation of the PFC is directly involved in the behavioral effects of PTZ, suggesting a role for it in anxiety.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130000390
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  • 30
    Digitale Medien
    Digitale Medien
    In vivo estimates of efficacy at 5-HT1A receptors: effects of EEDQ on the ability of agonists to produce lower-lip retraction in rats (2000)
    Springer
    Psychopharmacology 149 (2000), S. 377-387 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words 5-HT1A agonist ; Intrinsic activity ; Efficacy ; Irreversible antagonism ; Lower-lip retraction ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Maximal responses are often used as a measure of intrinsic activity or efficacy, but cannot be directly equated to efficacy. Using irreversible antagonists, estimates of efficacy can be obtained that may be less dependent on specific conditions. Objectives: To characterize the intrinsic activity of serotonin (5-HT)1A agonists by examining the effects of an irreversible antagonist on their ability to produce 5-HT1A receptor-mediated responses. Methods: The effects of N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) on the ability of 5-HT1A agonists to produce lower-lip retraction (LLR) in rats were studied. Results: In the absence of EEDQ, each 5-HT1A agonist produced full effects, the rank order of potency being: S 14506 〉 8-OH-DPAT 〉 buspirone 〉 ipsapirone. EEDQ decreased the number of 5-HT1A binding sites and shifted the dose–response curves (DRCs) of each agonist either to the right or, at higher EEDQ doses, to the right and downward. The manner in which these shifts occurred, however, differed among the compounds. For each agonist, all DRCs obtained after different doses of EEDQ were fitted to models proposed by Furchgott and Black and Leff, and the results indicated the following rank order of efficacy: ipsapirone 〈 buspirone ≈ 8-OH-DPAT 〈 S 14506. 5-HT1A agonist-induced LLR appears to be mediated by 5-HT1A receptors, because the 5-HT1A antagonist, WAY 100635, shifted the agonist DRCs to the right in a parallel and dose-related manner, with pA2 values ranging from 7.8 to 8.1. Moreover, pretreatment with WAY 100635 protected against the antagonist activity of EEDQ. Conclusions: The results suggest that the effects of EEDQ on the ability of 5-HT1A agonists to produce LLR in rats may be useful to obtain estimates of their apparent efficacy at 5-HT1A receptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130000374
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  • 31
    Digitale Medien
    Digitale Medien
    Human interferon-α increases immobility in the forced swimming test in rats (2000)
    Springer
    Psychopharmacology 148 (2000), S. 106-110 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Interferon ; Depression ; Forced swimming test ; Locomotor activity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objectives: We examined the immobility of the forced swimming test induced in an animal model by human interferon (IFN), which has often been reported to induce depression in clinical use. Methods: In the present study, we examined the effects of human IFNs on results of the forced swimming test in rats. Results: Single intravenous (IV) administration of human IFN-α (6×104 IU/kg), but not of human IFN-β or -γ, significantly increased immobility time in the forced swimming test in rats. Repeated administration of human IFN-α (6×103 IU/kg) also significantly increased the immobility time. On the other hand, none of the rat IFNs (rat IFN-α, -β and -γ, 6×104 IU/kg, IV) changed the immobility time. Neither human IFNs nor rat IFNs changed the locomotor activity of rats. Conclusions: These findings suggest that human IFN-α has a greater potential for inducing increase of the immobility in the rat forced swimming test than human IFN-β and -γ, and that the effect of human IFN-α might not be mediated through IFN-α/β receptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050031
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  • 32
    Digitale Medien
    Digitale Medien
    Selective mu and delta, but not kappa, opiate receptor antagonists inhibit the habituation of novelty-induced hypoalgesia in the rat (2000)
    Springer
    Psychopharmacology 148 (2000), S. 99-105 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Opiate receptor ; Antinociception ; Habituation ; Novelty ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: There is now extensive evidence demonstrating that exposure to novel stimuli induces hypoalgesia and that this effect habituates over repeated exposure to the stimuli. Moreover, it has been shown that administration of the nonselective opiate receptor antagonist naloxone can attenuate the rate of habituation of novelty-induced hypoalgesia. Objectives: The present experiments were conducted to determine the relative influence of different opiate receptor subtypes in the attenuation of the habituation of novelty-induced hypoalgesia. Methods: In experiments 1–3, different groups of male, Wistar rats (275–300 g) were administered vehicle, 0.5, 1.0 or 2.0-nmol doses of the µ-selective antagonist Cys2-Tyr3-Orn5-Pen7-amide (CTOP), the δ-receptor selective antagonist naltrindole, or the κ-selective antagonist nor-binaltorphimine (nor-BNI). In experiment 4, animals were administered vehicle, 5, 25 or 75-nmol doses of nor-BNI. All injections were delivered to the right lateral ventricle 30 min prior to exposure to a novel hot-plate apparatus (48.5°C), once a day for eight consecutive days. Results: Paw-lick latencies in vehicle-treated animals were long during the initial exposures and declined over repeated tests, suggesting the habituation of novelty-induced hypoalgesia. The rate of habituation was significantly attenuated by administration of 1.0-nmol and 2.0-nmol doses of CTOP, by a 2.0-nmol dose of naltrindole, but was unaffected by all doses of nor-BNI. Conclusions: These results support the involvement of the µ and δ, but not the κ, opiate receptor subtypes in the habituation of novelty-induced hypoalgesia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050030
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  • 33
    Digitale Medien
    Digitale Medien
    Discriminative stimulus effects of two doses of fentanyl in rats: pharmacological selectivity and effect of training dose on agonist and antagonist effects of mu opioids (2000)
    Springer
    Psychopharmacology 148 (2000), S. 136-145 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Fentanyl ; mu opioids ; Drug discrimination ; Training dose ; pA2 analysis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Discriminative stimulus effects of mu opioids vary systematically as a function of training dose. Differences among training doses may arise from multiple mechanisms. Objectives: In vivo apparent pA2 analyses were used to examine the contributions of opioid mechanisms to stimulus control by low and high training doses of the mu opioid fentanyl. Methods: Saline and one of two doses of fentanyl, administered s.c., were established as discriminative stimuli in two groups of rats (low training dose group: 0.01 mg/kg; high training dose group: 0.04 mg/kg). Generalization tests and in vivo apparent pA2 analyses were used to evaluate receptor mechanisms of stimulus control. Results: Fentanyl, etonitazene, methadone, and morphine evoked full fentanyl generalization in both groups but were more potent in the low-dose group. Spiradoline and d-amphetamine did not evoke generalization in either group. Naltrexone antagonized stimulus and rate-altering effects of fentanyl in both groups, with apparent pA2 values of 7.6 in the low-dose group and 7.5 in the high-dose group. Nalbuphine and nalorphine evoked full generalization in the low-dose group but less than 40% generalization in the high-dose group. In the high-dose group, nalbuphine and nalorphine antagonized the stimulus and rate-altering effects of fentanyl with apparent pA2 values of 5.3 and 6.1, respectively, demonstrating lower efficacy mu actions. Conclusions: Changes in fentanyl training dose preserved the mu opioid selectivity of stimulus control but altered the intensity of the transduced mu opioid stimulus required for generalization. These differences in intensity of the fentanyl stimulus determined whether low efficacy mu opioids would evoke or antagonize fentanyl generalization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050035
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  • 34
    Digitale Medien
    Digitale Medien
    Behavioral tolerance to the force differentiation effects of diazepam and midazolam in rats (2000)
    Springer
    Psychopharmacology 148 (2000), S. 327-335 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Benzodiazepine ; Operant ; Force ; Tolerance ; Chronic ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Several benzodiazepines (BZs) have been shown to increase the peak force of operant responses at doses that increased, decreased, or had no effect on response rate, suggesting that operant response force may be a sensitive index of BZs’ effects rather than solely a correlate of rate-dependent effects. In addition, contingent tolerance to the rate-dependent effects of BZs has been reported, but the degree of contingent tolerance that develops when the critical variable of the task is force of the response has not been explored. Objectives: These experiments examined the effects of acute and repeated oral administration of diazepam (DZ) and midazolam (MZ) on a force-differentiation task to explore the importance of task requirements on the development of contingent tolerance. Methods: Two groups of rats were trained to press a force-sensing operandum, and responses having peak forces falling within fixed lower and upper limits [low force (8–10 g) or high force (40–50 g)] were reinforced with water. Acute effects of the oral administration of DZ (0.3, 1.0, 3.0, 10.0, 30.0 mg/kg) and MZ (same doses) were determined for the discriminated-force task before and after a repeated-administration procedure. Results: When administered acutely, both drugs increased the peak force of responses in a dose-related manner and concomitantly reduced the proportion of reinforced responses, with MZ exhibiting greater potency. For the next 36 days, one group received drug before experimental sessions and the other group received drug after the experimental session. A second dose–effect determination demonstrated that rats chronically dosed with DZ or MZ pre-session displayed more contingent tolerance to alterations in peak force than rats that had received 36 drug injections post- session, where there was no opportunity to practice the force-discrimination response while under the drug state. Conclusions: These results suggest that perceptual motor difficulty of the task rather than effort may be an important variable in predicting the degree of contingent tolerance that develops. Additionally, these results suggest that both behavioral and pharmacological mechanisms are involved in the development of drug tolerance to the BZs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050059
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  • 35
    Digitale Medien
    Digitale Medien
    Discriminative stimulus properties of alprazolam (2000)
    Springer
    Psychopharmacology 148 (2000), S. 146-152 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Alprazolam ; Drug discrimination ; Benzodiazepines ; Antidepressant ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: The triazolobenzodiazepine alprazolam has a unique clinical profile compared to most other benzodiazepines (e.g. diazepam, chlordiazepoxide), in that it is used to treat panic disorder and is effective in depression, two disorders that are usually treated with anti-depressants. Previous drug discrimination studies suggested that alprazolam has stimulus properties in common with antidepressants. Objective: In the present study, the discriminative stimulus properties of alprazolam were investigated to test more conclusively the role of benzodiazepine receptors and whether alprazolam has stimulus properties in common with antidepressants. Methods: Male Wistar rats (n=12) were trained to discriminate between alprazolam (2.0 mg/kg, PO) and vehicle in an operant two-lever drug discrimination procedure under a tandem VI40”-FR10 schedule of reinforcement. Generalization and antagonism tests were carried out under 2 min extinction. Results: In generalization tests, a number of benzodiazepines (alprazolam, chlordiazepoxide, midazolam, lorazepam) and the barbiturate pentobarbital substituted completely, while zolpidem and abecarnil substituted partially for alprazolam. In contrast, no significant degree of generalization to the antidepressants imipramine and fluvoxamine and the putative antidepressants buspirone and flesinoxan was found. In antagonism studies alprazolam could be antagonized (almost) completely by flumazenil, partially by pentylenetetrazole, but not by methyl 6,7-dimethoxy-4-ethyl-β-carboline-3-carboxylate (DMCM), N-methyl-β-carboline-3-carboxamide (FG-7142) and picrotoxin. Conclusions: These results show that the discriminative stimulus properties of alprazolam are mediated by benzodiazepine receptors and that the finding that antidepressants share discriminative stimulus effects with alprazolam may have limited generality.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050036
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  • 36
    Digitale Medien
    Digitale Medien
    Dopaminergic involvement in the discriminative-stimulus effects of methamphetamine in rats (2000)
    Springer
    Psychopharmacology 148 (2000), S. 209-216 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Methamphetamine ; Drug-discrimination ; Dopamine ; Cocaine ; GBR-12909 ; Nomifensine ; Bupropion ; Chloro-PB ; Chloro-APB ; NPA ; 7-OH-DPAT ; SCH-23390 ; Spiperone ; cis-Flupenthixol ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Dopamine plays a major role in the behavioral effects of methamphetamine. Objective: In the present experiments, the effects of different dopaminergic agonists, antagonists, and uptake inhibitors were evaluated in rats discriminating methamphetamine from saline. Methods: In Sprague-Dawley rats trained to discriminate 1.0 mg/kg methamphetamine, i.p., from saline under a fixed-ratio schedule of food delivery, the ability of various dopaminergic agonists and uptake inhibitors to substitute for methamphetamine was evaluated. Subsequently, the ability of various dopaminergic antagonists to block the discriminative-stimulus effects of the training dose of methamphetamine was tested. Results: The dopamine-uptake inhibitors cocaine (10.0 mg/kg), nomifensine (3.0 mg/kg), GBR-12909 (18.0 mg/kg), and bupropion (30.0 mg/kg) fully substituted for the 1.0 mg/kg training dose of methamphetamine. Chloro-APB (SKF-82958), a full agonist at D1 dopamine receptors, produced about 85% methamphetamine-appropriate responding, but the dose required (0.18 mg/kg) markedly decreased rates of responding. Chloro-PB (SKF-81297), another agonist at D1 receptors with a lower intrinsic activity than Chloro-APB, produced only partial generalization (maximum about 55%) at a dose of 1.0 mg/kg. Full substitution for the training dose of methamphetamine was observed with 0.03 mg/kg of the D2 agonist NPA and 0.56 mg/kg of the D3/D2 agonist 7-OH-DPAT. Both NPA and 7-OH-DPAT markedly decreased rates of responding at these doses. The D1 antagonist SCH-23390 (0.056 mg/kg), the D2 antagonist spiperone (0.18 mg/kg), and the mixed D1,D2 antagonist cis-flupenthixol (0.56 mg/kg) all completely blocked the discriminative-stimulus actions of the training dose of methamphetamine. Conclusions: The present findings in rats support previous research findings in other species indicating a major role of dopamine in the discriminative-stimulus effects of methamphetamine. These findings further indicate involvement of dopamine uptake sites as well as D1 and D2 receptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002130050044
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  • 37
    Digitale Medien
    Digitale Medien
    Opiate withdrawal-induced place aversion lasts for up to 16 weeks (2000)
    Springer
    Psychopharmacology 149 (2000), S. 115-120 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Key words Opiate ; Withdrawal ; Place aversion ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Rationale: Administration of low doses of opiate antagonists to morphine-dependent rats produces an aversive response as measured by a conditioned place aversion, but the time course of such a learned aversion is largely unknown. Objectives: The purpose of this experiment was to examine the time course for the expression of a place aversion to opiate withdrawal. Methods: Morphine-dependent rats were tested in a three-chamber place- aversion apparatus. The conditioning phase consisted of three pairings of either naloxone (15 µg/kg s.c.) or vehicle with two compartments, with the most similar time allotments during the preconditioning test. During the testing phase, rats were again allowed to explore the entire apparatus. Different groups were tested at 24 h, 1 week, 2 weeks, 4 weeks, 8 weeks, and 16 weeks post-conditioning (morphine-free tests). Results: A robust place aversion was recorded at every time point tested, including at 16 weeks. In previously published work, placebo-pelleted rats tested with naloxone at the same dose failed to show a place aversion and nondependent rats showed a stable lack of aversion at tests up to 56 days. Dependent animals without naloxone also failed to show a place aversion at any of those time points. Conclusions: In the absence of any active intervention, the place aversion produced by opiate withdrawal is very long lasting and provides a model for protracted abstinence that may be useful for delineating the neurobiological substrate for vulnerability to relapse.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002139900358
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  • 38
    Digitale Medien
    Digitale Medien
    Halothane anesthesia decreases the extracellular level of dopamine in rat striatum: a microdialysis study in vivo (2000)
    Springer
    Journal of anesthesia 14 (2000), S. 82-90 
    Details
    ISSN: 1438-8359
    Schlagwort(e): Key words: Halothane ; Dopamine release ; Dopamine uptake ; Microdialysis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose. In our previous microdialysis study, sevoflurane or isoflurane anesthesia significantly decreased the extracellular level of dopamine in rat striatum in vivo. On the other hand, other investigators demonstrated that halothane anesthesia either increased or did not affect the extracellular dopamine level. To explore the differences among these volatile anesthetics, the effects of halothane and nitrous oxide on the striatal dopamine level were reinvestigated. Methods. Halothane alone, nitrous oxide with or without halothane, or drugs known to affect the dopaminergic pathway were administered to rats. Microdialysates were collected every 20 min and directly applied to an on-line high-performance liquid chromatograph without any pretreatment. The effects of halothane on respiratory and cardiovascular variables were monitored. Results. General anesthesia with halothane alone de-creased the dialysate (extracellular) concentration of dopamine but increased that of dopamine metabolites. Nitrous oxide alone slightly increased dopamine metabolites in dialysates but did not affect the halothane-induced decrease in extracellular dopamine. Apomorphine and haloperidol reproduced reported results, confirming the adequacy of our methodology. Nomifensine- or methamphetamine-induced increase in extracellular dopamine was augmented by halothane. Conclusion. These results suggest that halothane po-tently enhances striatal dopamine release and activates the reuptake or metabolic process, which is consistent with our previous results for sevoflurane or isoflurane. Volatile anesthetics interfere with dopamine regulation, at least in the rat striatum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s005400050072
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  • 39
    Digitale Medien
    Digitale Medien
    Development of the bones and synovial joints in the rat model of the VATER association (2000)
    Springer
    Journal of orthopaedic science 5 (2000), S. 390-396 
    Details
    ISSN: 1436-2023
    Schlagwort(e): Key words Adriamycin ; Rat ; Embryo ; VATER association ; Synovial joint ; Bones ; Limbs ; Vertebra ; Sirenomelia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The adriamycin-induced rat model of the Vertebral, Anorectal, Tracheo-Esophageal, Radial and Renal (VATER) association produces a variety of vertebral, rib, and limb abnormalities. This study was designed to document accurately the nature of these abnormalities and to determine whether synovial joints are affected. Fetuses from pregnant Sprague Dawley rats that had received intraperitoneal injections of 1.75 mg/kg of adriamycin on days 6–9 or 10–13 of gestation were harvested. Double-stained skeletal preparations and histological sections were examined for vertebral, rib, and limb anomalies. The incidence of anomalies was high in the group treated on gestational days (GD) 6–9, while it was low in the GD 10–13 group. The length and thickness of the long bones were reduced, with bowing and reduction in their endochondral ossification. Sirenomelia occurred in the group treated on GD 6–9, and was often associated with a short tail and anal atresia. The joint cavities, and intra-articular structures such as menisci and the cruciate ligaments developed normally from the mesenchymal interzone. These data indicate that adriamycin inhibits skeletal growth and differentiation without any interference in the differentiation of the mesenchymal interzone, thus producing normal synovial joints.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s007760050015
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  • 40
    Digitale Medien
    Digitale Medien
    ras p21 isoprenylation inhibition induces flat colon tumors in Wistar rats (2000)
    Springer
    Diseases of the colon & rectum 43 (2000), S. 70-75 
    Details
    ISSN: 1530-0358
    Schlagwort(e): Pravastatin ; ras p21 isoprenylation ; Colon carcinogenesis ; Flat colon tumor ; Azoxymethane ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract PURPOSE: The effect of pravastatin, an inhibitor ofras p21 isoprenylation, on the gross type of colon tumors induced by azoxymethane was investigated in Wistar rats. METHODS: Rats received ten weekly subcutaneous injections of 7.4 mg/kg body weight of azoxymethane and intraperitoneal injections of 10 or 20 mg/kg body weight of pravastatin every other day until the end of the experiment at Week 45. RESULTS: Administration of pravastatin at both dosages had no significant effect on the incidence of colon tumors but significantly increased the incidence of rats with adenomas only. In contrast to the elevated adenomas in control rats, flat adenomas were significantly more prevalent in rats given pravastatin. Pravastatin at both doses significantly decreased the labeling index, but not the apoptotic index, of elevated adenomas, whereas it significantly decreased the labeling index but increased the apoptotic index of flat adenomas. Administration of pravastatin at both dosages also significantly decreased the amounts of membrane-associatedras p21 in colon tumors. CONCLUSIONS: These findings suggest that theras oncogene may be closely related to the development of adenocarcinomas from adenomas and the development of elevated or polypoid tumors of the colon.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02237247
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  • 41
    Digitale Medien
    Digitale Medien
    A polymorphism of the rat T-cell receptor β-chain variable gene 13 (BV13S1) correlates with the frequency of BV13S1-positive CD4 cells (2000)
    Springer
    Immunogenetics 51 (2000), S. 296-305 
    Details
    ISSN: 1432-1211
    Schlagwort(e): Key words Vβ13 ; CD4/CD8 ratio ; Rat ; Tcrb ; Polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Three rat BV13S1 alleles (T-cell receptor β-chain variable gene 13) were characterized by new BV13S1-allele specific monoclonal antibodies (18B1 and 17D5) and sequence analysis of expressed and genomic BV13S1. Two alleles were functional and designated BV13S1A1 present in strains LEW, BUF, PVG, and BV13S1A2 present in BN and WF. Their products differed by six amino acids, two of them in complementarity-determing region (CDR)1 and one in CDR2. A third nonfunctional allele, BV13S1A3P, was found in strains F344 and DA. Apart from a single nucleotide insertion, it was identical to BV13S1A2. All 12 rat strains tested showed association of TCRBC1 with BV8S2/4 alleles but not with the BV13S1 alleles, which may reflect a different gene order of the rat BV compared to mouse. BV13S1A1-encoded T-cell receptors (TCRs) which bind both monoclonal antibody (mAb) 18B1 and mAb 17D5 are over-represented in the CD4 lymphocyte subset. BV13S1A2-encoded TCRs which are stained by mAb 18B1 but not by mAb 17D5 show a slight CD8-biased expression. Preferential usage of BV13S1A1-positive TCRs by CD4 but not by CD8 cells in (LEW×WF)F1 hybrids and cosegregation of BV13SA1 and increased frequency of BV13S1 TCR-positive CD4 cells in a (LEW×BN)×BN backcross suggest structural differences of the two allelic products as the reason for their contrasting CD4/CD8 subset bias.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002510050623
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  • 42
    Digitale Medien
    Digitale Medien
    Morphological analysis of peripheral nerve regenerated by means of vein grafts filled with fresh skeletal muscle (2000)
    Springer
    Anatomy and embryology 201 (2000), S. 475-482 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Key words Nerve repair ; Nerve fiber regeneration ; Sciatic nerve ; Muscle-vein-combined graft ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Clinical data have shown that a vein segment filled with fresh skeletal muscle can be considered a good autologous grafting conduit for the repair of peripheral nerve lesions. In this study, the long-term morphological organization of rat sciatic nerve fibers regenerated along a muscle-vein-combined graft conduit is further analysed by light and electron microscopy. Regenerated nerve fibers were organized into fascicles of various sizes that were clearly delimited by perineurial-like shells made by long and thin cytoplasmic processes of perineurial-like bipolar cells and by densely packed collagen fibrils. Grafted skeletal muscle fibers were still detectable among nerve fiber fascicles. However, in spite of the persistence of skeletal muscle along the graft, regenerated nerve fibers showed a good morphological pattern of regeneration, providing further evidence that the muscle-vein-combined grafting technique represents an effective surgical alternative to the classical fresh nerve autograft for the repair of peripheral nerve defects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004290050334
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  • 43
    Digitale Medien
    Digitale Medien
    NK1, NK2 and NK3 tachykinin receptor localization and tachykinin distribution in the ileum of the mouse (2000)
    Springer
    Anatomy and embryology 202 (2000), S. 247-255 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Key words Enteric neurons ; Interstitial cells of Cajal ; Smooth muscle cells ; Guinea-pig ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Tachykinin receptors NK1r, NK2r and NK3r bind tachykinins with different affinities and share pharmacological and molecular differences among animal species. NK1r, NK2r, NK3r and tachykinin (SP/NKA) distribution was studied by immunohistochemistry in the ileum of mouse since no data are available for this species. The results were then compared to those obtained in the rat and guinea pig either by us or by others to ascertain interspecies similarities and/or differences. NK1r- and NK3r-immunoreactivity (IR) were detected in neurons and NK1r-IR in the interstitial cells of Cajal at the deep muscular plexus. At variance with rat and guinea pig, NK1r-IR was also found in the myoid cells of the villi, while NK2r-IR was never detected in nerve varicosities. This latter datum suggests that the NK2r does not play a presynaptic role in the mouse. Unexpectedly, a high NK2r-IR and the presence of NK3r-IR were observed at the inner portion of the circular muscle layer in the mouse as well as in the rat and guinea pig, demonstrating a subregional distribution of these receptors. Tachykinin distribution did not show noticeable species-related differences. The present findings show species-related differences in the tachykinin receptor distribution that might be related to a different tachykinin controlof intestinal motility.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004290000106
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  • 44
    Digitale Medien
    Digitale Medien
    Immunocytochemical distribution of the GABAB receptor splice variants GABAB R1a and R1b in the rat CNS and dorsal root ganglia (2000)
    Springer
    Anatomy and embryology 201 (2000), S. 1-13 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Key words GABAB receptor ; CNS ; Dorsal root ganglia ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The anatomical distribution of the GABAB receptor (GBR) splice variants GBR1a and 1b in the CNS has not previously been studied. In the present study, distribution of the splice variants was mapped using immunohistochemistry. Polyclonal antibodies against splice variant unique epitopes were raised in rabbits. Affinity purified antibodies were used according to routine immunohistochemical procedures in sections from the rat CNS or dorsal root ganglia (DRG). The staining intensity was high in the cerebral cortex but lower in basal ganglia and the hippocampus. In the cerebellum, there was a marked difference in the distribution of GBR1a- and 1b-like immunoreactivity (LI). GBR1a-LI was preferentially localised in the granule cell layer whilst GBR1b-LI was mostly found in Purkinje cells and in the molecular layer. Cell bodies of the deep cerebellar nuclei stained for the GBR1a antibody while terminals surrounding the cell bodies were strongly labelled with the GBR1b antibody. A similar pre- vs postsynaptic pattern was seen in several nuclei ventral or caudal to the cerebellum (e.g. the cochlear nucleus, the facial nucleus, the spinal cord) but not in regions rostral to the cerebellum. In the spinal cord, strong labelling for both antibodies was seen in the dorsal horn. The GBR1b but not the GBR1a antibody stained tanycytes in the epithelium of the 3rd ventricle and in the central canal at the brain stem level. DRG neurons were positive for both the GBR1a and 1b antibody, but the former stained the cells much more intensely. Satellite cells were labelled with the GBR1b antibody. The most important aspect of these findings is that in some nuclei, GBR1b may mediate inhibition of transmitter release while in the same regions, GBR1a may mediate postsynaptic inhibition. Further, the observations support previous findings that GBR1b is the predominant splice variant in Purkinje cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00008224
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  • 45
    Digitale Medien
    Digitale Medien
    Modulation of Paired-Pulse Responses in the Dentate Gyrus: Effects of Normal Maturation and Vigilance State (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 128-134 
    Details
    ISSN: 1573-9686
    Schlagwort(e): Hippocampus ; Vigilance states ; Paired-pulse ; Dentate gyrus ; Dentate granule cells ; Evoked response ; Rat ; In vivo studies ; Perforant path ; Maturation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract This study examined the effect of normal development and vigilance state on the modulation of dentate granule cell activity in the freely moving rat at 15, 30, and 90 days of age across three vigilance states: quiet waking, slow-wave sleep, and rapid eye movement sleep. Using paired-pulse stimulation, the paired-pulse index (PPI) was obtained for the dentate evoked field potentials elicited by the stimulation of the medial perforant path. Although significant differences in PPI values were observed during development, no significant vigilance state related changes were obtained. Preweaning infant rats, i.e., 15-day old, exhibited significantly less early (interpulse intervals, IPI= 20–50 ms) and late (IPI = 300–1000 ms) inhibition, and less facilitation (IPI = 50–150 ms) when compared to the 90-day old adult rats during all three vigilance states. PPI values obtained from the 30-day old group fell intermediate between the 15- and 90-day old animals. These changes in PPI values provide a quantitative measure of changes in the modulation of dentate granule cell excitability during normal maturation. They can now can be used to evaluate the impact of various insults, such as prenatal protein malnutrition or neonatal stress, on hippocampal development. © 2000 Biomedical Engineering Society. PAC00: 8717Nn, 8719La, 8719Nn
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1114/1.261
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  • 46
    Digitale Medien
    Digitale Medien
    Left Ventricular Contractility is Impaired Following Myocardial Infarction in the Pig and Rat: Assessment by the End Systolic Pressure–Volume Relation Using a Single-Beat Estimation Technique and Cine Magnetic Resonance Imaging (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 484-494 
    Details
    ISSN: 1573-9686
    Schlagwort(e): Heart ; Left ventricle ; LV contractility ; ESPVR ; Pig ; Rat ; Magnetic resonance imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract The end systolic pressure–volume relation (ESPVR) has been shown to be a relatively load independent measure of left ventricular (LV) contractility. Recently, several single-beat ESPVR computation methods have been developed, enabling the quantification of LV contractility without the need to alter vascular loading conditions on the heart. Using a single-beat ESPVR method, which has been validated previously in humans and assumes that normalized elastance is constant between individuals of a species, we studied the effects of myocardial infarction on LV contractility in two species, the rat and the pig. In our studies, LV pressure was acquired invasively and LV volume determined noninvasively with magnetic resonance imaging, at one week postinfarction in pigs and at 12 weeks postinfarction in rats. Normalized systolic elastance curves in both animal species were not statistically different from that of humans. Also, the slope of the ESPVR $$\left( {E_{es} } \right)$$ decreased significantly following infarction in both species, while the volume-axis intercept $$\left( {V_0 } \right)$$ was unaffected. These results indicate that a single-beat ESPVR method can be used to measure the inotropic response of the heart to myocardial infarction, and that the basis for this method (i.e., constant normalized elastance) is applicable to a variety of mammalian species. © 2000 Biomedical Engineering Society. PAC00: 8719Uv, 8761Lh, 8719Hh, 8719Rr, 8719Ff
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1114/1.289
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  • 47
    Digitale Medien
    Digitale Medien
    Quantifying Coevolution of Nonstationary Biomedical Signals Using Time-Varying Phase Spectra (2000)
    Springer
    Annals of biomedical engineering 28 (2000), S. 1101-1115 
    Details
    ISSN: 1573-9686
    Schlagwort(e): Time–frequency analysis ; Coherence ; Cross correlation ; Nonstationary persistent signals ; Central pattern generator ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract We present a novel time-varying phase spectrum (TVPS) method to quantify the dynamics of coevolution of two persistent nonstationary coupled signals. Based on the TVPS, an instantaneous intersignal phase shift is defined within the primary frequency range in which the two signals are highly correlated. The TVPS is estimated using a fixed-window method or an adaptive-window method. In the latter method, the window length changes dynamically and automatically as a function of change in frequency of the signals. The effects of altering window types and lengths on the accuracy of the estimation of the primary phase shift is assessed by analyzing synthesized linear chirp signals with decaying amplitude and constant relative phase shift or decaying amplitude and changing relative phase shifts. The methods developed are also used for determining the evolution of the primary phase shift among ventral root activities during fictive locomotion in an in vitro rat spinal cord preparation. The analyses indicate that the TVPS method in conjunction with the determination of the primary frequency range, allows determination of both the evolution of the coupling strength and the evolution of the phase shift between two persistent nonstationary rhythmic signals in the joint time–frequency domain. An adaptive window reduces the estimation bias and the estimation variability. © 2000 Biomedical Engineering Society. PAC00: 0230-f, 8780Tq
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1114/1.1313775
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  • 48
    Digitale Medien
    Digitale Medien
    c-Fos Expression by Dopaminergic Receptor Activation in Rat Hippocampal Neurons (2000)
    Springer
    Molecules and cells 10 (2000), S. 546-551 
    Details
    ISSN: 0219-1032
    Schlagwort(e): c-Fos ; Dopamine ; D1 ; Hippocampus ; Rat ; Synaptic Plasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract While dopamine is likely to modulate hippocampal synaptic plasticity, there has been little information about how dopamine affects synaptic transmission in the hippocampus. The expression of IEGs including c-fos has been associated with late phase LTP in the CA1 region of the hippocampus. The induction of c-fos by dopaminergic receptor activation in the rat hippocampus was investigated by using semiquantitative RT-PCR and immuno-cytochemistry. The hippocampal slices which were not treated with dopamine showed little expression of c-fos mRNA. However, the induction of c-fos mRNA was detected as early as 5 min after dopamine treatment, peaked at 60 min, and remained elevated 5 h after treatment. Temporal profiles of increases in c-fos mRNA by R(+)-SKF-38393 (50 μM) and forskolin (50 μM) were similar to that of dopamine. An increase in [cAMP] was observed in dopamine-, SKF-, or forskolin-treated hippocampal slices. By immunocytochemical studies, control hippocampal cells showed little expression of c-Fos immunoreactivity. However, when cells were treated with dopamine, an increase in the expression of c-Fos immunoreactivity was observed after treatment for 2 h. The treatment of hippocampal neurons with R(+)-SKF38393 (50 μM) or forskolin (50 μM) also induced a significant increase in c-Fos expression. These results indicate that the dopamine D1 receptor-mediated cAMP dependant pathway is associated with the expression of c-Fos in the hippocampal neurons. These data are consistent with the possible role of endogenous dopamine on synaptic plasticity via the regulation of gene expression. Furthermore, these results imply that dopamine might control the process of memory storage in the hippocampus through gene expression.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s10059-000-0546-y
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  • 49
    Digitale Medien
    Digitale Medien
    Systemic treatment with epidermal growth factor but not insulin-like growth factor I decreases the involution of the prostate in castrated rats (2000)
    Springer
    Urological research 28 (2000), S. 75-81 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Key words Castration ; Epidermal growth factor ; Insulin-like growth factor I ; Prostate ; Testosterone ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I) are strong inducers of proliferation to prostate cells cultured in serum-free medium. Accordingly we wanted to study the growth of the prostate gland in castrated rats after treatment with EGF, IGF-I and testosterone. Castrated Wistar rats were treated with growth factors (EGF 35 μg/rat per day; IGF-I 350 μg/rat per day) or testosterone (2 mg/rat per day) for 3 days either immediately after or 10 days after castration. Prostate tissue was examined by stereological and immunohistochemical techniques and by enzyme-linked immunosorbent assay (ELISA). Treatment with EGF inhibited the involution of the prostate (P 〈 0.05), whereas treatment with IGF-I did not affect the prostate involution as compared to castrated controls. EGF treatment significantly increased the endogenous rat EGF in the ventral prostate, but cellular proliferation was not affected. Testosterone treatment increased the weight of the prostate, by increase of all tissue components of the prostate, and significantly increased cellular proliferation. Systemic administration of EGF but not IGF-I decreased the involution of the rat prostate induced by castration. Compared with testosterone, the effects of EGF treatment on the prostate involution were moderate, and the effects of EGF were not related to cellular proliferation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002400050141
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  • 50
    Digitale Medien
    Digitale Medien
    Effect of aging on bladder function and the response to outlet obstruction in female rats (2000)
    Springer
    Urological research 28 (2000), S. 33-37 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Key words Bladder ; Rat ; Aging ; Obstruction ; Cystometrics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Bladder dysfunction in the aging population is a significant problem. However the concomitant presence of other diseases in many patients can make it difficult to distinguish between changes in bladder function and other influences. The present study was designed to study, in aging rats, bladder function and the effect of partial bladder outlet obstruction (BOO) on bladder function. Cystometrics were performed in awake, female Fischer 344 rats of four age groups (6, 12, 18 and 24 months) following subcutaneous implantation of a mediport catheter. Cystometric evaluations were carried out in control rats or those subject to three weeks of BOO. Bladder compliance significantly decreased with aging, which reflected an increase in threshold pressure without changes in bladder capacity. Partial BOO caused development of severe bladder instability. Following BOO, bladder capacity and compliance were significantly increased in all age groups. Threshold pressure was lower in obstructed animals, except for 6-month rats. Younger animals were able to generate a higher contraction pressure to compensate for the BOO, whereas older animals did not. Using an awake model of cystometric measurement, we have demonstrated that aging, by itself can affect bladder function. Furthermore, aged animals respond differently to BOO than younger animals. These results demonstrate that both aging and disease can contribute to bladder dysfunction, and suggest that treatment of bladder dysfunction may require a combination of therapies targeted to multiple etiologies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002400050007
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  • 51
    Digitale Medien
    Digitale Medien
    Real-time monitoring of nitric oxide in ischemia-reperfusion rat kidney (2000)
    Springer
    Urological research 28 (2000), S. 141-146 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Key words Kidney ; Nitric oxide ; Ischemia-reperfusion injury ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In this study we attempted to clarify the release of nitric oxide (NO) and its role in the ischemia-reperfusion rat kidney. After right nephrectomy, male Wistar rats were divided into four groups: one sham operated and three groups who underwent ischemia (30 min) and reperfusion of the left renal artery. Thirty minutes prior to ischemia-reperfusion, two groups were injected intraperitoneally with 10 and 30 mg/kg of NG-nitro-l-arginine methylester (L-NAME). Real-time monitoring of blood flow and NO release in the rat kidney was measured with a laser Doppler flowmeter and an NO-selective electrode, respectively. Serum creatinine and blood urea nitrogen (BUN) levels were measured 1 and 7 days after the induction of ischemia-reperfusion. Clamping of the renal artery decreased blood flow to 1–5% of the basal level measured before clamping. After removal of the clip, the blood flow of the 30 mg/kg L-NAME rats was significantly lower than that of the controls. Immediately following the clipping of the renal artery, NO release rapidly increased. After removing the clip, NO release immediately returned to three-quarters of the basal level. Serum creatinine and BUN levels of the ischemia-reperfusion rats were slightly but not significantly higher and those of 30 mg L-NAME rats were significantly higher than those of the control or ischemia-reperfusion rats 1 day and 7 days after ischemia-reperfusion. Our data suggest that NO acts as a cytoprotective agent in ischemia-reperfusion injury of the rat kidney.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002400050153
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  • 52
    Digitale Medien
    Digitale Medien
    Mechanomyograms recorded during evoked contractions of single motor units in the rat medial gastrocnemius muscle (2000)
    Springer
    European journal of applied physiology 83 (2000), S. 310-319 
    Details
    ISSN: 1439-6327
    Schlagwort(e): Key words Motor unit ; Mechanomyography ; Evoked contraction ; Medial gastrocnemius muscle ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Acoustic phenomena accompanying contractions of single motor units (MUs) have previously received little attention. Therefore, in the present study, the mechanomyographic (MMG) signals during evoked contractions of single MUs have been recorded from the medial gastrocnemius muscle of the rat. A piezoelectric transducer immersed in a paraffin-oil pool was used for the measurement of these signals. Muscle fibre action potentials, tension and MMG were recorded in parallel during twitch (the weakest) and fused tetanic (the strongest) MU contractions. It was observed that the onset of the MMG signals was coincident with the beginning of the increase in tension for both the twitch and tetanus. Weaker MMG signals than those accompanying the beginning of the first phase of the fused tetanus were seen during the beginning of the relaxation after tetanic contraction. During contraction and relaxation, MMG signals were characterised by the reverse-direction of the first extreme phase, positive and negative, respectively. No MMG signals were observed when the tension was constant during the fused tetanus. The amplitude of MMG signals was correlated with both the tension increase and the velocity of tension increase during both the twitch and the fused tetanus. The strongest MUs (fast fatiguable) generated MMG signals of the highest amplitude. MMG signals were not detected for some of the weakest slow MUs (with tension increases of ≤2 mN). These results indicate a strong correlation between the MMG and the change of tension. Therefore, we believe that MMG signals are generated by muscle deformation that occurs during the contraction of MU muscle fibres. We conclude that the number of active muscle fibres, their topography, and their localisation in relation to the muscle surface (which is variable for different types of MUs) influence these MMG phenomena.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004210000261
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  • 53
    Digitale Medien
    Digitale Medien
    Regional Spinal Cord Blood Flow and Energy Metabolism in Rats after Laminectomy and Acute Compression Injury (2000)
    Springer
    European journal of trauma 26 (2000), S. 122-130 
    Details
    ISSN: 1615-3146
    Schlagwort(e): Key Words Spinal cord compression ; Autoradiography ; Blood flow ; ATP ; Glucose ; Lactate ; Bioluminescence ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Many data are available concerning spinal cord blood flow (SCBF) and metabolism on various models and timing after spinal cord injury, however, detailed information on their exact relationship in the same injury model is lacking. This relationship is a crucial factor in the understanding of the pathophysiology of spinal cord trauma. Rats were subjected to lumbar laminectomy or lumbar spinal cord compression trauma. 3 hours later, changes in SCBF were evaluated autoradiographically and changes in ATP, glucose and lactate levels were analyzed using substrate-specific bioluminescence techniques. Measurements were performed at the lesion site (segment L4), adjacent segments (L3 and L5) and at remote thoracic segments (Th8 to Th9). Laminectomy alone did not change SCBF, both in thoracic and lumbar segments. In contrast, ATP levels were significantly reduced and lactate levels were increased at the lesion site and in adjacent lumbar segments at 3 hours after laminectomy, whereas glucose levels were not significantly changed. In animal subjected to additional compression trauma, SCBF was significantly reduced in segments L3, L4 and L5 paralleled by a significant ATP reduction and lactate increase. Glucose levels did not differ significantly from controls 3 hours after compression injury. This metabolic profile was also reflected in the remote thoracic segments. In contrast, SCBF was not reduced in thoracic segments of traumatized animals. The observation that ATP was already significantly reduced and lactate increased in laminectomized segments and in remote thoracic regions after trauma signals that metabolic changes are sensitive indicators to spinal stress. The fact that posttraumatic metabolic profile differs from the pattern of hemodynamic and metabolic changes induced by ischemia, suggests posttraumatic mediators may be involved in the different regulation of the energy producing machinery.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s000680050010
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  • 54
    Digitale Medien
    Digitale Medien
    Detection and analysis of gastrointestinal sounds in normal and small bowel obstructed rats (2000)
    Springer
    Medical & biological engineering & computing 38 (2000), S. 42-48 
    Details
    ISSN: 1741-0444
    Schlagwort(e): Bowel sounds ; Rat ; Motility ; Body acoustics ; Signal detection ; Signal characterisation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract This study is aimed at detecting gastrointestinal sounds (GIS) and correlating their characteristics with gastrointestinal (GI) conditions. The central hypotheses are that GIS generation depends on the motility patterns and the mechanical properties of the gut, and that changes in those result in measurable differences in GIS. An animal model which included both healthy rats and those with small bowel obstruction (SBO) was developed. The acoustic bursts, of GIS were detected by amplitude thresholding the signal envelope. Three methods of envelope estimation were proposed and evaluated. Envelope estimation using a Hilbert transform was found to produce the best results in the current application. The duration and dominant frequency of each detected GIS event was estimated and clear differences between healthy and diseased rats were discovered. In the control state, GIS events were found to consistently be of relatively short duration (3–65ms). Although the majority of events in the SBO state had similar short duration, infrequent longer events were also detected and appeared to be pathognomonic. Long duration events (〉100 ms) occurred in each of seven obstructed, but in none of 14 non-obstructed, cases (p〈0.001). It is concluded that GIS analysis may prove useful in the non-invasive, rapid, and accurate diagnosis of SBO.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02344687
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  • 55
    Digitale Medien
    Digitale Medien
    Decreased expression of vascular endothelial growth factor in glomeruli of puromycin aminonucleoside nephrosis (2000)
    Springer
    Clinical and experimental nephrology 4 (2000), S. 29-33 
    Details
    ISSN: 1437-7799
    Schlagwort(e): Key words VEGF ; Glomeruli ; Ribonuclease protection assay ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background. Vascular endothelial growth factor (VEGF) is a selective endothelial growth factor which potently enhances microvascular permeability. In the kidney, VEGF mRNA is known to be highly expressed in visceral epithelial cells in glomeruli. However, the physiological role of VEGF in glomerular function and its involvement in the pathogenesis of proteinuria are not clear. The present studies were designed to determine whether altered expression of VEGF mRNA was observed in the course of puromycin aminonucleoside (PAN) nephrosis in rats (a model of human minimal change nephrosis). Methods. The message level of VEGF in isolated glomeruli of PAN nephrosis rats was measured using a ribonuclease protection assay. Results. VEGF expression began to decrease 4 days after PAN injection and could not be detected in the nephrotic stage of PAN nephrosis (on days 8 and 16). In the remission of stage of PAN nephrosis (on day 28), mRNA was restored to the control level. Conclusions. According to our results, a functional defect in the VEGF expression of visceral epithelial cells was observed in PAN nephrosis. VEGF could be a functional marker of visceral epithelial cells, and the loss of normal expression of VEGF after damage to visceral epithelial cells could affect glomerular endothelial cell function in PAN nephrosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s101570050058
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  • 56
    Digitale Medien
    Digitale Medien
    Organ-specific distribution of major histocompatibility antigens in rats (2000)
    Springer
    Pediatric surgery international 16 (2000), S. 285-292 
    Details
    ISSN: 1437-9813
    Schlagwort(e): Key words Major histocompatibility complex (MHC) ; Rat ; Immunohistochemistry ; Distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The present study systematically investigated the expression and distribution of the major histocompatibility complex (MHC) classes I and II in the rat. About 150 native tissue probes from eight adult Lewis rats were taken, representative for most organs, tissues, and the vascular system. MHC expression was analyzed by two monoclonal antibodies (mAb) generated against the non-polymorphic determinants of rat MHC class I (Ox-18) and class II (Ox-6). Immunoreactivities were compared to those of different endothelial (HIS52, TLD-3A12, Ox-43, REHA-1 antigen), histiocytic (ED1, ED2), B-cell (RLN-9D3), and T-cell (MRC Ox-52) markers. A nonspecific mAb (MR12/53) served as a negative control. Pretested concentrations on various tissues and the alkaline phosphatase-anti-alkaline phosphatase technique allowed semiquantitative evaluation of serial cryostat tissue sections. MHC class I expression was detected on most immunocompetent cells. Endothelial cells were stained heterogeneously along the vascular system and the organ-specific microcirculation. Furthermore, some organs showed staining of parenchymal cells. MHC class II was found on all immunocompetent cells positive for the B-cell marker and about 15% of cells positive for the histiocytic markers. Besides the well-known expression of MHC class II in the outer zone of the renal proximal tubule, further organ-specific cell forms were found positive. In conclusion, the present study outlines tissue-specific distribution of MHC I/II and implies that each organ carries a variable immunologic burden that needs to be considered for any transplantation model.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003830050746
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  • 57
    Digitale Medien
    Digitale Medien
    Proliferation, zonal maturation, and steroid production of fetal adrenal transplants in adrenalectomized rats (2000)
    Springer
    Pediatric surgery international 16 (2000), S. 293-296 
    Details
    ISSN: 1437-9813
    Schlagwort(e): Key words Fetal transplantation ; Proliferation ; Adrenal glands ; Addisonian crisis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The present study investigated the histologic maturation, proliferative capacity, and steroid production of fetal adrenal transplants (Tx) in adrenalectomized rats. A pair of fetal adrenal glands (18–20 days of gestation) was transplanted into the omentum of syngeneic Lewis rats (n=45). Four weeks later, in 5 animals the grafts were excised for morphologic evaluation. Proliferation was investigated by immunohistochemical staining for KI-67 protein and quantified by the proliferation index (PI = positive cells/100 counts). All other hosts (Tx; n = 40) underwent bilateral adrenalectomy (AE) to induce Addisonian crisis. Postoperatively, survival and concentrations of potassium, sodium, aldosterone, and corticosterone were recorded for 6 months. These data were compared to controls (C = only AE; n = 30) and a sham group (S; n = 10). At the end of the study period all surviving hosts were killed for histologic examination of grafts. At 4 weeks post-Tx the adrenal grafts demonstrated a distinct zona glomerulosa and frequent proliferation with a PI of 0.084, comparable to normal control (0.092). Following AE survival was significantly prolonged in Tx (86% vs 12% of C, P 〈 0.05). Control animals developed severe hyponatremia and hyperkalemia, whereas in Tx only transient signs of Addisonian crisis were recorded. Levels of aldosterone dropped within 7 days in the Tx and C groups, but returned to normal for Tx within 8 weeks. Corticosterone levels of Tx animals fell to 25% within week, but steadily increased to 70% by the end of the study. At 6 months, grafts revealed a mature adrenocortical structure with little proliferative activity, which was comparable to controls. In a syngeneic rat model fetal adrenal transplants thus mature and proliferate to provide sufficient steroid production for adrenalectomized hosts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003830050747
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  • 58
    Digitale Medien
    Digitale Medien
    Antenatal dexamethasone administration inhibits smooth-muscle-cell DNA synthesis in pulmonary-arterial media in nitrofen-induced congenital diaphragmatic hernia in rats (2000)
    Springer
    Pediatric surgery international 16 (2000), S. 414-416 
    Details
    ISSN: 1437-9813
    Schlagwort(e): Key words Congenital diaphragmatic hernia ; Hypoplastic lung ; Bromodeoxyuridine (BrdU) ; Antenatal glucocorticoids ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The aim of this study was to investigate the effect of antenatal glucocorticoid therapy on smooth-muscle-cell (SMC) DNA synthesis in the pulmonary arteries (PA) in a nitrofen-induced congenital diaphragmatic hernia (CDH) rat model following nitrofen administration on day 9.5 of gestation. Antenatal dexamethasone (DEX) was given intraperitoneally on days 18.5 and 19.5 of gestation. Bromodeoxyuridine (BrdU) was injected via a jugular vein into the dam 1 h before the fetuses were killed by cesarean section at term. The fetuses were divided into three groups: group I (n = 10): normal controls; group II (n = 10): nitrofen-induced CDH; group III (n = 10): nitrofen-induced CDH with antenatal DEX treatment. Immunostaining of the lungs with anti-BrdU antibody was obtained by a standard avidin-biotin complex method. The number of immunopositive cells in the PA media and adventitia were counted using an image analyzer and analyzed statistically. The number of BrdU-immunopositive cells in the media was significantly increased in group II (16.83 ± 3.01) compared to groups I (9.16 ± 2.20) and III (6.83 ± 1.70) (P 〈 0.01). There was no significant difference between groups I and III. The number of BrdU-immunopositive cells in the adventitia was not significantly different between the three groups. Antenatal DEX treatment inhibits SMC DNA synthesis in PA media in CDH lungs. This may be a possible mechanism by which antenatal DEX prevents structural PA changes in nitrofen-induced CDH in rats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003839900336
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  • 59
    Digitale Medien
    Digitale Medien
    Apoptosis in murine duodenum during embryonic development (2000)
    Springer
    Pediatric surgery international 16 (2000), S. 485-487 
    Details
    ISSN: 1437-9813
    Schlagwort(e): Key words Duodenum ; Apoptosis ; Fetus ; Rat ; Duodenal atresia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Duodenum is thought to go through a solid-core stage followed by recanalization during its development. This study investigates the role of apoptosis in normal duodenal development, especially during widening of the lumen, and hence, the possible role of apoptosis in duodenal atresia (DA). Twenty-four time-mated Sprague-Dawley rats were killed from day 13 to day 20 of gestation. Duodenums of 3 fetuses were chosen randomly from each rat and processed. Apoptosis was determined by the terminal deoxytransferase-mediated biotin dUTP nick-end labeling (TUNEL) technique (ApopTag). Apoptosis count and cross-sectional areas were measured with an image analyzer (MetaMorph). The number of apoptotic cells per unit area duodenum peaked on day 15 for the mucosal/submucosal layer and on day 14 for the muscular/mesenchymal layer. The maximal number of apoptotic cells per cross-section of duodenum was between 7 and 8. The cross-sectional areas of the duodenal wall and lumen increased exponentially between day 17 and day 19 while duodenal-wall thickness remained relatively constant throughout duodenal development. The localization, timing, and intensity of apoptosis do not suggest that apoptosis is responsible for the widening of the duodenal lumen; enlargement of the lumen is related to the increase in duodenal circumference. Apoptosis thus may not be involved in the pathogenesis of DA.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003830000408
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  • 60
    Digitale Medien
    Digitale Medien
    Die Trennung kolloid gelöster Stoffe von niedermolekular gelösten Stoffen an der Silicagelsäule (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 51-62 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: By adding acid or base to Fe(III) nitrate solutions low molecular and colloidal products of hydrolysed Fe(III) ions are formed. The colloid dissolved products pass silicagel columns faster than all other constituents of the solutions. The retention volume of colloidal products does not depend on the pH of the solution, but is specific for the distribution state; it is smaller than the retention volume of chlorine ions of a sodium chloride solution.The possibility of a complete separation of both, low molecular and colloidal componentsin a column of silicagel is calculated and controlled by experiments.
    Notizen: In Eisen(III)-nitratlösungen werden durch Zusätze von Säure oder Lauge niedermolekular und kolloid gelöste Hydrolyseprodukte des Eisenions erzeugt. Diese Lösungen werden an Silicagelsäulen chromatographiert. Dabei erscheinen die kolloid gelösten Hydrolyseprodukte als die am schnellsten transportierten Bestandteile. Ihr Retentionsvolumen ist pH-unabhängig und nicht spezifisch für den Stoff, sondern für den Verteilungszustand. Es ist kleiner als das Retentionsvolumen der Cl--Ionen einer NaCl-Lösung. Die Möglichkeit einer vollständigen Trennung beider Stoffe in einer Silicagelsäule wird berechnet und experimentell bestätigt.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270107
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  • 61
    Digitale Medien
    Digitale Medien
    Investigations on Cyano Complexes. II. Cyano Mercurate(II)-complexes (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 89-92 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Durch potentiometrische Titrationen in konzentrierten KCN-Lösungen wurden außer den in der Literatur bekannten Komplexen die Anionen [Hg(CN)5]3- und [Hg(CN)6]4- ermittelt. Instabilitätskonstanten, Standardpotentiale und freie Energien wurden berechnet. Sobald über die Formel Hg(CN)2 hinaus ein kleiner Überschuß von HgCl2-Lösung zugegeben wurde, bildete sich Hg2Cl2 auf der Elektrode.
    Notizen: By potentiometric titrations, in addition to the complexes known in literature, the anions [Hg(CN)5]3- and [Hg(CN)6]4- have been evaluated in concentrated solutions of KCN. Instability constants together with standard potentials and free energies were calculated. - After the complete formation of Hg(CN)2 and addition of slight excess of HgCl2 the electrode became incapacitated on account of the formation of Hg2Cl2.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270112
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  • 62
    Digitale Medien
    Digitale Medien
    Über Phosphor-Stickstoff-Verbindungen. XVI. Die Synthese der Phosphornitrid-dichlorideProfessor Otto Schmitz-DuMont zum 65. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 128-138 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The synthesis of phosphorus nitride dichlorides [NPCl2]n, from PCl5 and NH4Cl proceeds through cations of the type [Cl3P=N—PCl3]+ and [Cl3P=N—(PCl2=N)n—PCl3]+, respectively. The reaction steps have been elucidated.The synthesis of [NPCl2]3 is favourably achieved starting directly from [Cl3P=N—PCl2=N—PCl3]+ or from PCl5 and NH4Cl in such a manner that this cation is predominantly formed in high dilution. [NPCl2]4 is best prepared by interaction between [Cl3P=N—PCl3]Cl and NH4Cl.Higher polymeric, oily phosphorus nitride dichlorides are suitably synthesized from strongly concentrated solutions or melts.
    Notizen: Die Synthese von Phosphornitrid-dichloriden, [NPCl2]n, aus PCl5 und NH4Cl verläuft Über Kationen der allgemeinen Zusammensetzung [Cl3P=N=PCl3]+, bzw. [Cl3P=N—(PCl2=N)n&PCl3]+. Die einzelnen Reaktionsschritte können geklärt werden. Zur Synthese von [NPCl2]3 geht man zweckmäßig von [Cl3P=N—PCl2=N—PCl3]+ aus  -  bzw. man arbeitet bei der Synthese so, daß aus PCl5 und NH4CL vorwiegend dieses Kation entstehen muß und sorgt durch Verdünnungsmittel für eine Begünstigung einer Ringschlußreaktion - . Zur Synthese von vorwiegend [NPCl2]4 empfiehlt sich die Umsetzung von [Cl3P=N—PCl3]Cl mit NH4Cl. Die öligen Phosphornitrid-dichloride erhält man vorwiegend aus stark konzentrierten Lösungen bzw. Schmelzen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270305
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  • 63
    Digitale Medien
    Digitale Medien
    Some Reactions of N-BromobistrifluoromethylamineDedicated to Professor Otto Schmitz-DuMont on his 65th birthday (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 147-150 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: N-Brom-bis(trifluormethyl)-amin, (CF3)2NBr, reagiert mit NO2, NO und CO unter Bildung von (CF3)2NONO, (CO3)2NNO bzw. (CF3)2NCOBr. Das schon beobachtete einheitliche Reaktionsverhalten des (CF3)2NBr gegenüber einfachen ungesättigten Kohlenstoffverbindungen wurde auch bei C2H4, C2H2 sowie C2F4 gefunden, die (CF3)2NC2H4Br. (CF3)2NC2H2Br bzw. (CF3)2NC2F4Br ergeben. Mit AgCN wird CF3N = CF2 gebildet, und die Reaktion mit Ag2CO3 liefert als Hauptprodukt CF3N = NCF3.
    Notizen: N-Bromobistrifluoromethylamine, (CF3)2NBr reacts with NO2, NO and CO to yield (CF3)2NONO, (CF3)2NNO and (CF3)2NCOBr, respectively. The reaction of (CF3)2NBr with unsaturated hydrocarbons and fluorocarbons has been confirmed, reaction with C2H4 C2H2 and C2F4 giving (CF3)2NC2H4Br, (CF3)2NC2H2Br and (CF3)2NC2F4Br. Reaction with AgCN yields CF3N = CF2, and that with Ag2CO3, CF3N = NCF3, as the chief product.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270308
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  • 64
    Digitale Medien
    Digitale Medien
    Oxydationsprodukte intermetallischer Phasen. I. Untersuchungen am NaTlO2Professor Otto Schmitz-DuMont zum 65. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 199-206 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: By slowly oxydation of NaTl, a new cubic form of NaTlO2 has been obtained: a=4.76 Å, dx=7.99 and dpyk=7.98 g · cm-3, NaCl type of structure, 2 formula units/unit cell, with random distribution of the cations. At 500°C it transforms to the known hexagonal form of NaTlO2, and annealing (700—750°C) for 6 days yields single crystals of the latter form, the crystal structure of which has been refined by means of FOURIER methods.
    Notizen: Durch langsame Oxydation von NaTl wird eine neue, kubische Form von NaTlO2 erhalten: a=4,76 Å, drö=7,99 und dpyk=7,98 g · cm-3, NaCl-Typ mit statistischer Verteilung der Kationen, 2 Formeleinheiten/Elementarzelle. Diese wandelt sich bei 500°C in die bekannte hexagonale Form um und liefert bei sechstägigem Tempern (700—750°C) im verschlossenen Ag-Bömbchen Einkristalle der zweiten Form. Mit Hilfe von FOURIERmethoden wurde deren Kristallstruktur verfeinert.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270313
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  • 65
    Digitale Medien
    Digitale Medien
    Über Mischkristallbildung in den Systemen (NH4)3AlF6 — (NH4)3GaF6 und LiAl — LiGaProfessor Otto Schmitz-DuMont zum 65. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 143-146 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Methods of preparation and the results of x-ray investigations of the mixed-crystal systems (NH4)3AlF6—(NH4)3GaF6 and LiAl—LiGa are reported. Both systems form complete series of solid solutions. The variation of the lattice constants obeys VEGARDs rule.
    Notizen: Die Darstellung von Mischkristallen in den Systemen (NH4)3AlF6—(NH4)3GaF6 und LiAl—LiGa wird beschrieben, und die Ergebnisse von Röntgenuntersuchungen werden mitgeteilt. Beide Systeme bilden eine lückenlose Mischkristallreihe. Der Verlauf der Gitterkonstanten zeigt keine systematischen Abweichungen von einer VEGARDschen Geraden.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270307
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  • 66
    Digitale Medien
    Digitale Medien
    Untersuchungen über das komplexchemische Verhalten des 1-Oxy-1-aminomethylcyclohexans. IProfessor Otto Schmitz-DuMont zum 65. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 191-198 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The complex-forming interaction occuring in alcoholic solutions between 1-hydroxy-1-aminomethyl-cyclohexane and nickel and cobalt salts has been investigated. The ligand is normally bidentate (formation of 5-membered chelate rings), in a few compounds, however, it behaves like a monodentate ligand. The structures and properties of the complex compounds being formed are compared with those having the isomeric 1-amino-1-hydroxymethyl-cyclohexane or ethanolamine as ligands.
    Notizen: Es wurde das komplexchemische Verhalten des 1-Oxy-1-aminomethylcyclohexans (Oxyamin) untersucht. Die Base bildet mit Salzen von Nickel und Kobalt in alkoholischer Lösung Verbindungen höherer Ordnung. Der Ligand besetzt bevorzugt zwei Koordinationsstellen unter Ausbildung von Chelat-5-Ringen. In einigen Verbindungen muß er aber z. T. auch als einzählig gebunden betrachtet werden. Die Tendenz, Innerkomplexe zu bilden, ist beim 1-Oxy-1-aminomethylcyclohexan nicht so ausgeprägt, wie bei dem isomeren 1-Amino-1-oxymethylcyclohexan. Die Struktur der Komplexverbindungen wurde im Vergleich mit analog zusammengesetzten Verbindungen des Äthanolamins diskutiert.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270312
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  • 67
    Digitale Medien
    Digitale Medien
    Berechnung der Wirkungsradien der edelgasähnlichen lonen vermittels der ultravioletten Spektren der zugehörigen EdelgaseProfessor Otto Schmitz-DuMont zum 65. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 215-223 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: All the parameters of PAULINGS equation (see above) for the estimation of the radii of noble-gas type ions having the charge w can be evaluated from the UV spectra of hydrogen and the noble gases, namely, the effective nuclear charge Z*, the empirical constant c valid for each long period of the periodical system, and the BORN repulsive exponent n.Thus, only from spectroscopical data, the ionic radii of noble-gas type ions have been calculated and are compared with those given by PAULING, GOLDSCHMIDT and AHRENS by means of empirical reference data.
    Notizen: Im Jahre 1927 hat PAULING die Gleichung: zur Berechnung von Radien edelgasähnlicher Ionen der Wertigkeit w aufgestellt. Die hierfür erforderlichen Größen: die effektive Kernladungszahl Z* der Ionen, die für jede lange Periode des Periodischen Systems gültige empirische Konstante c und der BORNSche Abstoßungsexponent n können, wie in vorliegender Arbeit gezeigt wird, vermittels der UV-Spektren des Wasserstoffs und der Edelgase berechnet werden. Hierdurch wird die Möglichkeit erhalten, die Ionenradien sämtlicher edelgasähnlichen Ionen spektroskopisch zu ermitteln. Die Kenntnis der Ionenabstände in Kristallen mit isoelektronischen Ionenpaaren (wie bei PAULING) oder irgendeines Bezugsradius (wie bei GOLDSCHMIDT) ist hierbei nicht erforderlich.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270315
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  • 68
    Digitale Medien
    Digitale Medien
    Metadata (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964) 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270501
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  • 69
    Digitale Medien
    Digitale Medien
    Über Untersuchungen im System Kupfer/Mangan/Sauerstoff (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 275-280 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The products of the thermal decompositions of mixed carbonates, oxalates, and nitrates of copper and manganese have been investigated chemically and by x-ray techniques.Similarly, the products of interactions between Cu2O, CuO or Cu and MnO, Mn2O3 or MnO2 are studied.The double oxide CuMnO2 has been prepared in the pure state.
    Notizen: Die thermischen Zersetzungsprodukte gemeinsam gefällter Carbonate und Oxalate sowie gemeinsam eingedampfter Nitrate des Kupfers und Mangans wurden chemisch und röntgenographisch untersucht. Gemische aus Kupfer(I)-bzw. Kupfer(II)-oxid sowie Kupfer einerseits und Mangan(II)-, Mangan(III)- und Mangan(IV)-oxid andererseits wurden im Sauerstoff- und Stickstoffstrom sowie im Hochvakuum umgesetzt und ihre Reaktionsprodukte chemisch und röntgenographisch untersucht. Das Doppeloxid CuMnO2 wurde erstmalig rein dargestellt.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270502
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  • 70
    Digitale Medien
    Digitale Medien
    Über Silikone, LXX. Über Die Rolle geringer Mengen von Aluminium-oder Eisenchlorid bei der direkten Synthese von Methylchlorsilanen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 293-301 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The reaction of methyl chloride with silicon demands a second catalyst besides copper. Satisfactory reaction velocities are especially achieved by means of AlCl3; FeCl3 and other metal chlorides being less active. AlCl3 activates two reaction steps: the interaction between methyl chloride and copper as well as that between silicon and copper(I) chloride. The chemisorption of methyl chloride, however, is not influenced by AlCl3.
    Notizen: Zur Umsetzung von Methylchlorid mit Silicium mit befriedigender Geschwindigkeit ist außer Kupfer noch ein zweiter Katalysator erforderlich. Als solcher eignen sich besonders AlCl3, in geringerem Maß auch FeCl3 und die Chloride einiger anderer Metalle. Das AlCl3 beschleunigt zwei Teilreaktionen: die Umsetzung von Methylchlorid mit Kupfer und diejenige von Silicium mit Kupfer(I)-chlorid. Die Chemisorption von Methylchlorid hängt dagegen vom Gehalt an AlCl3 nicht ab. Sie ist kein Maß für die Geschwindigkeit der direkten Synthese.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270505
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  • 71
    Digitale Medien
    Digitale Medien
    Über Aluminiumarsenid (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 187-193 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The preparations, properties and some reactions of AlAs crystals are described. The enthalpy of formation at room temperature, melting point as a function of the arsenic pressure, and the band gap determined by remission measurements are communicated.
    Notizen: Es wird die Herstellung von Aluminiumarsenid-Kristallen beschrieben. Von der Verbindung wurde die Bildungsenthalpie bei Zimmertemperatur, die Abhängigkeit des Schmelzpunktes vom Arsendruck und der Bandabstand durch Remissionsmessung bestimmt. Weiterhin ist das Verhalten des Aluminiumarsenids gegen einige Reagenzien angegeben.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280310
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  • 72
    Digitale Medien
    Digitale Medien
    Professor Dr. HAAKON HARALDSEN. zum 60. Geburtstage am 24. April 1964 (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 217-218 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280502
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  • 73
    Digitale Medien
    Digitale Medien
    Masthead (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964) 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280501
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  • 74
    Digitale Medien
    Digitale Medien
    Structure Lacunaire Ordonnée des Composés Ti3Se4 et Ti5Se8Dedié au Professeur Haakon Haraldsen à l'occasion du 60e anniversaire (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 231-234 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Beschreibung der Strukturen (mit geordneten Leerstellen) der nichtstöchiometrischen Verbindungen Ti3Se4 und Ti5Se8.
    Notizen: Déscription de la structure lacunaire des composés non stoechiométriques Ti3Se4 et Ti5Se8.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280505
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  • 75
    Digitale Medien
    Digitale Medien
    RAMAN- und Infrarotspektren der trimeren und tetrameren Phosphornitridhalogenide (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 326 (1964), S. 243-253 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: RAMAN spectra including polarization measurements and infrared spectra were taken from P3N3Cl6, P3N3Br6, P3N3F6. P4N4Cl8, P4N4Br8, and P4N4F8. Former observations and assignments for the chlorides and fluorides are corrected. Each molecule shows the highest possible symmetry with planar configuration and equal bonds within its PN ring.
    Notizen: RAMAN-Spektren einschließlich von Polarisationsmessungen und Infrarotspektren wurden von P3N3Cl6, P3N3Br6, P3N3F6, P4N4Cl8, P4N4Br8 und P4N4F8 aufgenommen. Frühere Beobachtungen und Zuordnungen für die Chloride und Fluoride werden korrigiert. Jede Molekel zeigt die höchste mögliche Symmetrie mit ebener Konfiguration und gleichen Bindungen im PN-Ring. Soweit die spektralen Veränderungen beim Übergang zu den Kristall-Modifikationen verständlich sind, sprechen sie für die gegebenen Zuordnungen.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643260505
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  • 76
    Digitale Medien
    Digitale Medien
    Arsen-organo-Verbindungen. II. Zur Synthese der Dialkylamino-dialkylarsine sowie der Dialkylarsine (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 326 (1964), S. 280-287 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The preparations of certain amino dialkyl arsines (R2As—N(C2H5)2 and R2As—NC5H10 with R = C2H5, C3H7 or C4H9) are discribed. These compounds react with H2O, CH3J or HCl by cleaving the As—N bond, forming R2AsCl in the last case. The dialkyl chloro arsines are reduced by LiAlH4 to the corresponding arsines.
    Notizen: Diäthylamino- und Piperidino-dichlorarsine reagieren mit aliphatischen Grignard-Verbindungen im Molverhältnis 1:2 unter Bildung der Amino-dialkylarsine R2As—N(C2H5)2 und R2As—NC5H10 (R = C2H5, C2H5, C3H7 oder C4H9). Die Amino-dialkylarsine sind äußerst hydrolyseempfindlich, wobei eine quantitative Spaltung der As—N-Bindung stattfindet. Eine Spaltung dieser Bindung resultiert gleichfalls mit HCl-Gas. Es werden hierbei Amin-hydrochloride und aliphatische Chlorarsine R2AsCl gebildet. Letztere lassen sich mit LiAlH4 zu den entsprechenden Dialkylarsinen R2AsH reduzieren. In den Amino-dialkylarsinen fungiert das Stickstoffatom als basisches Zentrum, wie aus der Ammoniumsalzbildung mittels CH3J zu folgern ist.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643260508
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  • 77
    Digitale Medien
    Digitale Medien
    Untersuchungen an oxidischen Katalysatoren. I. über einige Halbleitereigenschaften von Al2O3—Cr2O3-Mischkatalysatoren und deren Einfluß auf die dehydrierende Wirkung beim IsopropanolzerfallProfessor Günther Rienäcker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 18-30 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The electrical conductivity of oxides resp. mixed oxides in the system Al2O3—Cr2O3 prepared by decomposition of the corresponding coprecipitated hydroxide gels in hydrogen at 700° C has been measured in a stream of hydrogen. A reversible p-n-transition is found on all samples containing chromium oxide. The transition temperature depends on composition. The change of conductivity with composition will be discussed.The results of isopropyl alcohol dehydrogenation on the same oxides are reported. A linear relation is found between the dehydrogenation activity and the logarithm of the specific conductivity for two groups of catalysts. Feeble n-type oxides of low conductivity work preferably in the direction of dehydration. Dehydrogenation dominates with increasing n-type character and character and increasing conductivity. The results provide experimental evidence to support the views of Wolkenstein on the mechanism of alcohol dehydrogenation.
    Notizen: Die elektrische Leitfähigkeit der gemeinsam gefällten und bei 7000C in Wasserstoffatmosphäre geglühten Oxide bzw. Mischoxide des Systems Al2O3—Cr2O3 wird im Wasserstoffstrom gemessen. An allen chromoxidhaltigen Präparaten tritt eine reversible p-n-Umwandlung auf; die Umwandlungstemperatur hängt von der Zusammensetzung ab. Der Verlauf der Leitfähigkeit in Abhängigkeit von der Zusammensetzung wird diskutiert.Die Ergebnisse der an den gleichen Oxiden untersuchten katalytischen Isopropanoldehydrierung werden mitgeteilt. Für zwei Gruppen von Katalysatoren wird eine lineare Beziehung zwischen der Dehydrierungsaktivität und dem Logarithmus der spezifischen Leitfähigkeit gefunden. Schwache n-Leiter von geringer Leitfähigkeit wirken vorwiegend dehydratisierend, mit steigendem n-Charakter und zunehmender Leitfähigkeit überwiegt die Dehydrierung. Die Ergebnisse sprechen für die Gültigkeit des von Wolkenstein für die Alkoholdehydrierung aufgestellten Mechanismus.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290105
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  • 78
    Digitale Medien
    Digitale Medien
    Hydrolyse- und Kondensationsreaktionen im System Phosphoroxidbromid-WasserProfessor Günther Rienäcker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 56-67 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The existence of dibromophosphoric acid formed by hydrolysis of phosphoryl bromide in acetone-Water mixtures has been proved by titration and by precipitation of the nitron salt. By condensation of partially hydrolyzed phosphoryl bromide, mixtures of polyphosphoric acids are formed. The end groups of these acids are supposed to be substituted by bromine atoms.
    Notizen: Die Existenz der bei der Hydrolyse des Phosphoroxidbromids in Aceton-Wasser-Gemischen gebildeten Dibromophosphorsäure wurde titrimetrisch und durch Fällung des Nitronsalzes bewiesen. Durch Kondensationsreaktionen des partiell hydrolysierten Phosphoroxidbromids entstehen Gemische von Polyphorsäuren, deren Endgruppen wahrscheinlich durch Br-Atome substituiert sind.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290109
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  • 79
    Digitale Medien
    Digitale Medien
    Zur kenntnis des komplexchemischen Verhaltens von Schwefel-und Selen-haltigen Eisencarbonyl-VerbindungenProfessor Günther Rienücker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 92-101 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Di-μ-organylthio-bis(tricarbonyliron)-compounds [Fe(CO)3XR]2 (X = S, Se; R = C2H5, C6H5) react with tertiary organic phosphines (L) in organic solvents forming nonsymmetrically substituted products Fe2(CO)5L(XR)2. The reaction with molten phosphines leads to symmetrically substituted derivatives [Fe(CO)2L XR]2. Reduction of this class of compounds with sodium amalgame in tetrahydrofuran leads to polynuclear sodium carbonylferrates, especially Na2[Fe3(CO)11] and sodium mercaptide.
    Notizen: Di-μ-merkapto-bis(tricarbonyleisen)-Verbindungen [Fe(CO)3XR]2 (X = S, Se; R = C2H5, C6H5) reagieren mit Triorganylphosphinen (L) in unpolaren Lösungsmitteln unter Bildung von unsymmetrisch gebauten Monosubstitutionsprodukten Fe2(CO)5L(XR)2. Unter den schärferen Bedingungen der Phosphin-Schmelze entstehen symmetrische disubstituierte Derivate [Fe(CO)2LXR]2. In beiden Fällen bleibt die Brückenstruktur der μ-Merkapto-Verbindungen erhalten. Reduktionen mit Natriumamalgam in Tetrahydrofuran führen in unübersichtlicher Reaktion unter Abspaltung von Natriummerkaptid zu mehrkernigen Carbonylferraten homogenen Bautyps, vorwiegend zum Na2[Fe3(CO)11].
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290113
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  • 80
    Digitale Medien
    Digitale Medien
    über ein blaues ZirkonnitridProfessor Günther Rienäclcer zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 136-145 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: By ammonolysis of zirconium tetraiodide at 750°C, of zirconium tetrabromide and chloride at slightly higher temperatures, we obtained a zirconium nitride of dark blue colour and a composition ZrxN with 0,940〉 x 〉 0,812. The amount of Zr3+ was determined analytically. At stronger heating the samples turn into metallic ZrN.The nitride crystallizes with the sodium chloride structure, the zirconium sublattice being only partly occupied. The lattice constants lie within the investigated range between 4,566 and 4,550 Å.The specific electric conductivity of ZrxN is about 3 · 10-2Ω-1 cm-1. The magnetic suseeptibility of the samples is about - 0,1 · 10-6.
    Notizen: 1Durch Ammonolyse von Zirkontetrajodid bei etwa 750°C, von Zirkontetrabromid und Zirkontetrachlorid bei etwas höheren Temperaturen wurde ein Zirkonnitrid von dunkelblauer Farbe der Zusammensetzung ZrxN mit 0,940〉x〉 0,812 erhalten. Analytisch wurde u. a. der Gehalt an Zr3- bestimmt. Die Präparate gehen bei stärkerem Erhitzen in metall lisches ZrN über.2Das Nitrid kristallisiert im Natriumchlorid-Gitter mit Fehlstellen auf dem Zirkonteilgitter; die Gitterkonstanten liegen für die genannten Grenzen zwischen 4,566 und 4,550 Å.3Das spezifische elektrische Leitvermögen des ZrxN ist etwa 3. 10-2 · -1 cm-1. Die magnetische Suszeptibilität der Präparate ist etwa -0,1 · 10-6.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290117
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  • 81
    Digitale Medien
    Digitale Medien
    Zustandsdiagramm des Systems Zn(ClO3)2-H2OProfessor Günther Rienäcker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 203-210 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The compounds which crystallize from aqueous solution of zinc chlorate, depending on the concentration and the temperature, are Zn(ClO3)2 · 12 H2O (m. p. -24,9° C), zn(ClO3)2 · 6H2O(m. p. +16,4° C), Zn(ClO3)2 · 4H2O(m. p. 53,9 °C), and Zn(ClO3)2 · 2H2O. The dihydratc melts at 114°C, but it begins to decompose at this temperature. Six quadruple points exist in the system, two of them lying in fields in which the hydrates in question are instable resp. metastable.
    Notizen: Aus wässerigen Lösungen von Zinkchlorat kristallisieren, je nach der Konzentration und der Temperatur der Lösungen, die Verbindungen Zn(ClO3)2 · 12 H2O (Fp.-24,9° C), Zn(ClO3)2 · 6 H2O (Fp. + 16,4° C), Zn (ClO3)2 · 4H2O (Fp. 53,9°C) und Zn(ClO3)2 ·2H2O. Das Dihydrat schmilzt bei 114° C, beginnt sich aber gleichzeitig unter Abspaltung von ClO2 zu zersetzen. In dem System treten 6 Quadrupelpunkte auf, von denen 2 in Gebieten liegen, in denen die betreffenden Hydrate instabil bzw. metasbil sind.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290123
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  • 82
    Digitale Medien
    Digitale Medien
    Wasserstoffverbindungen von Schwermetallen. VII. Eine Wasserstoffverbindung des WolframsProfessor Günther Rienäcker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 218-224 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: W(C6H5)4(LiC6H5)2 · 3 (C2H5)2O react with H2 in absolute absence of air and moisture to form WH(LiC6H5)2. The preparation and the properties of the compound are described and a reactionshene is stated.
    Notizen: Aus W(C6H5)4(LiC6H5)2 · 3 (C2H5)2O und H2 entsteht unter Luft- und Feuchtigkeitsausschluß WH(LiC6H5)2. Darstellung und Eigenschaften der Vervindung werden beschrieben und Angaben über den Reaktionsablauf gemacht.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290125
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  • 83
    Digitale Medien
    Digitale Medien
    Katalyse an Einkristallen. IV. Dehydrierung von Butanol-2 an verschiedenen Kristallflächen des GermaniumsProfessor Günther Rienäcker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 261-268 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The dehydrogenation of butanol-2 was examined on different crystal faces of a germanium single crystal by means of the static method. There is a large catalytic specifity of the crystal faces. At 390° C the reaction rate on the (100) face is eleven times larger than on the (III) face. The differences in the activation energies are 15 keal/mol. The results are discussed.
    Notizen: An verschiedenen Kristallächen eines Germanium-Einkristalls wurde die Dehydrierung von Butanol-2 nach der statischen Methode untersucht. Die einzelnen Kristallflächen weisen eine große katalytische Spezifität auf. An der (100)-Fläche verläuft die Reaktion bei 390° C elfmal schneller als an der (III)-Fläche. In den Aktivierungsenergien treten Unterschiede von 15 keal/Mol auf. ie Ergebnisse werden diskutiert.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290130
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  • 84
    Digitale Medien
    Digitale Medien
    über die Polymerenbildung der Reaktionsprodukte AsOX bzw. X2AsOAsX2 von Arsenik in Lösungen von AsCl3, AsBr3, AsF3 und As(OCH3)3Professor Günther Rienäcker zum 60. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 329 (1964), S. 244-260 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Diluted solution of arsenic(III)-oxide, As4O6, in AsCl3, AsBr3, AsF3 and As(OCH3)3 have been investigated cryoscopically and ebullioscopically. The results indicate that the As4O6 molecule is solvolysed according to As4O3 + 8AsX3 → 6AsOX · AsX3. Furthermore, reversible polymerzation equilibra (AsOX)n-1· AsX3 + AsOX · AsX3 ⇄ AsX3 + (AsOX)n · AsX3 are supposed to occur yielding, at a total composition of the solutions being AsOX, high-molecular (AsOX)n.The saturation curves of the two-phase equilibria in the system As2O3-AsCl3-cyclohaxane and -petroleum ether, respectively, are communicated as well as some hithero unknown thermodynamic data on AsF3 and As(OCH3)3.
    Notizen: Die verdünnten Lösungen des Arseniks (As4O6) in AsCl3, AsBr3, AsF3 und As(OCH3)3 wurden kryoskopisch bzw. ebullioskopisch untersuscht. In allen Fällen ergab sich eine Aufspaltung der As4O6- Molekel in sechs Teilchen, bei höheren Konzentrationen z. T. in weniger. Die Beobachtungen werden erklärt durch die Reaktion As4O3 + 8AsX3 → 6AsOX · AsX3 und reversible Polymerisationsgleichgewichte (AsOX)n-1 ·AsX3 + AsOX · AsX3 ⇄ AsX3 + (AsOX)n · AsX3. Entsprechend wird für die Lösungen der Zusammensetzung AsOX eine hochmolekulare Struktur (AsOX)n vorgeschlagen. Für die Zusammensetzung AsOX eine hochmolekulare Struktur (AsOX)n vorgeschlagen. Für die Zweiphasengleichgewichte in den Dreistoffsystemen As2O3(gelöst)-AsCl3-Petroläther bzw. Cyclohexen werden die Sättigungslinien angegeben. Einige thermochemische Daten von AsF3 und As(OCH3)3 wurden bestimmt.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643290129
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  • 85
    Digitale Medien
    Digitale Medien
    Masthead (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 330 (1964) 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643300101
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  • 86
    Digitale Medien
    Digitale Medien
    Über Koordinationsverbindungen des Cadmiumdimethyls mit Äthern und tertiären Aminen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 330 (1964), S. 8-17 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Cadmium dimethyl reacts with 1,4-dioxane, N,N,N′,N′,-tetraethylethylenediamine, 2,2′-bipyridyl and 1,10-phenanthroline forming crystalline chelate compounds with one donor molecule attached to one molecule of cadmium dimethyl. These compounds are more stable against atmospherie oxygen than cadmium dimethyl itself.Univalent donor molecules like tetramethylene oxide or pyridine yield liquid 1:1 complexes which dissoziate into the components already at low temperatures; it is difficult, therefore, to isolate these compounds in a stoichiometric composition.
    Notizen: Cadmiumdimethyl bindet mit 1,4-Dioxan und N,N,N′,N′,-Tetraäthyläthylendiamin, 2,2′,-Dipyridyl und 1,10-Phenanthrolin kristalline Chelatverbindungen mit einer Ligandenmolekel pro Molekel Cadmiumdimethyl. Die Luftempfindlichkeit dieser Verbindungen ist wesentlich geringer als die des reinen Cadmiumdimethyls.Stärkere einwertige Liganden wie Tetrahydrofuran und Pyridin neigen zur Bildung von flüssigen 1:1-Addukten. Diese Komplexverbindungen spalten sich beim Erwärmen weitgehend in ihre Komponenten und lassen sich daher nur schwer in stöchiometrischer Zusammensetzung erhalten.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643300103
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  • 87
    Digitale Medien
    Digitale Medien
    Die Lichtabsorption des Co2+ und Ni2+ in oxidischen Festkörpern mit Granatstruktur. IProfessor Otto Schmitz-DuMont zum 65. Geburtstage gewidmet (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 238-252 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The fine structure of the garnet lattice was investigated by means of Co2+ and Ni2+ as "optical indicators". Co2+ was found to occupy sites of the coordination numbers 4, 6 and 8, Ni2+ being in tetrahedral and octahedral interstices only. The observed distribution of both ions over the different lattice positions was found to be strongly temperature dependent. The effect of changing the dimensions of the octahedral interstices on the crystal field strength Dq and the interelectronic repulsion parameter B of Co2+ und Ni2+ in the tetrahedral and octahedral positions is considered.The results were obtained by a detailed analysis of the absorption spectra in the crystal field region between 4000 and 26000 cm-1.
    Notizen: Mit Hilfe der farbgebenden Ionen Co2+ und Ni2+ als "optische Indikatoren" wurde versucht, feinere Struktureigentümlichkeiten des Granatgitters zu erfassen.In den in der vorliegenden Arbeit untersuchten Germanium-Granaten wird das Co2+-Ion in allen drei verfügbaren Kationenpositionen (Koordinationszahlen 4, 6 und 8 gegenüber Sauerstoff), das Ni2+-Ion nur in Positionen der K.Z.4 und 6 gefunden.Die Auswirkungen von Veränderungen der Oktaederlückendimensionen auf die Gitterfeldstärken Dq und die Elektronenabstoßungsparameter B der in den Oktaeder- und Tetraederlücken befindlichen Kationen Ni2+ und Co2+ werden untersucht.Es werden Angaben über die Verteilung der Co2+ und Ni2+-Ionen über die verschiedenen Lückenarten des Granatgitters und ihre Temperaturabhängigkeit gemacht.Die Ergebnisse wurden durch eine detaillierte Analyse der Absorptionsspektren im Wellenzahlbereich zwischen 4000 und 26000 cm-1 und deren Interpretation auf der Grundlage der Kristallfeldtheorie erhalten.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270317
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  • 88
    Digitale Medien
    Digitale Medien
    Über Silikone. LXIX. Über die Induktionsperiode bei der direkten Synthese von Methylchlorsilanen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 286-292 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The synthesis of methylchlorosilanes by interaction between methyl chloride and Si—Cu mixtures proceeds through an induction period during which AlCl3 is formed from Al impurities in the technical-grade silicon. μ-Cu3Si has no determining importance for the course of the synthesis, especially in the presence of AlCl3.
    Notizen: Bei der Umsetzung von Methylchlorid mit Silicium-Kupfer-Gemischen entstehen Methylchlorsilane erst nach Ablauf einer Induktionsperiode, während der im technischen Silicium enthaltenes Aluminium in das für die direkte Synthese entscheidende Chlorid übergeführt wird. Röntgenanalysen ergaben, daß die Bildung der μ-Phase nicht unmittelbar mit der Überwindung der Induktionsperiode zusammenhängt. Die μ-Phase ist besonders bei Gegenwart von AlCl3 nicht maßgeblich für den Ablauf der direkten Synthese.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270504
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  • 89
    Digitale Medien
    Digitale Medien
    Spektropische Untersuchungen an Siliciumverbindungen. XX. Studien über die Lagebeeinflussung der IR-Absorptionsfrequenzen durch Aggregatzustandsänderung (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 327 (1964), S. 305-310 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: IR frequency shifts have been studied on compounds of the general formula R3SiX (R = alkyl groups, X = electronegative substituents). The shifts occur on condensing gaseous to liquid substances in consequence of intermolecular interactions or associations. A relation between the frequency shift of vs Si—X and the electronegativity of the substituent X has been found. This relation is, however, not suitable for the calculation of electronegativities.
    Notizen: Es wurden IR-Frequenzverschiebungen an Verbindungen des Typs R3SiX (R = Alkyl, X = elektronegativere Substituenten) studiert, die beim Übergang von der gasförmigen zur flüssigen Substanz infolge intermolekularer Wechselwirkung, bzw. Assoziation im flüssigen Zustand auftreten. Es ergibt sich ein Zusammenhang zwischen der Verschiebung der am stärksten betroffenen Si—X-Valenzschwingungsfrequenzen und der Elektronegativität des Substituenten X, der sich aber nicht zur Bestimmung von Elektronegativitäten eignet.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643270507
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  • 90
    Digitale Medien
    Digitale Medien
    Drucksynthese von Niobnitriden und Konstitution von δ-NbN (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 34-43 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Niobium nitrides are prepared from niobium metal powder and nitrogen at temperatures of 1200 to 1500°C and pressures up to 160 at. They belong either to the cubic δ phase or to the hexagonal ε phase. Their maximum nitrogen content corresponds to the formula NbN1.06(= Nb0.94N). The highest amount of all lattice vacancies of the cubic nitride being filled has been found at the composition NbN1.00.
    Notizen: Aus Niobmetallpulver und Stickstoff wurden bei Temperaturen von 1200 bis 1500°C und Drucken bis 160 at Niobnitride dargestellt. Sie gehören der kubischen δ-Phase oder der hexonalen ε-Phase an und können einen maximalen Stickstoffgehalt entsprechend einer Zusammensetzung NbN1,06(= Nb0,94N) erreichen. Der Gitterbesetzungsgrad der kubischen Nitride zeigt bei der Zusammensetzung NbN1,00 ein Maximum.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280105
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  • 91
    Digitale Medien
    Digitale Medien
    Zur Reaktion der Diphosphine R2P—PR2 mit Metallorganylen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 21-33 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: PhLi reacts at 20°C with tetraalkyl and tetraaryl diphosphines, R2P—PR2 (excepted (C6H11)4P2), by cleaving the P—P bond forming the corresponding tertiary phosphines and P-substituted Li phosphides. Similarly, Ph2As—AsPH2 gives Ph3As and LiAsPh2; with Ph2N—NPh2 no reaction occurs. MgEt2 and AlEt3 act in analogous manner only at elevated temperatures, while PbEt4 is indifferent. The influence on the course of the reaction is discussed regarding the kind of E in Ph2E—EPh2, the organic P substituents and the nucleophility of the organometallic compounds.
    Notizen: Mit Ausnahme des Tetracyclohexyl-diphosphins reagieren die Aryl- bzw. Alkyldiphosphine bei Raumtemperatur mit Phenyl-lithium unter Spaltung der P—P-Bindung und Bildung der entsprechenden tert. Phosphine sowie P-substituierten Lithium-phosphide. Während eine analoge Umsetzung zwischen Magnesiumdiäthyl und Tetraphenyldiphosphin bei 110-120°C beobachtet wird, tritt diese bei Verwendung von Aluminiumtriäthyl erst bei höherer Temperatur auf und bleibt mit Bleitetraäthyl aus.Der Spaltungsverlauf wird einmal durch den induktiven Effekt des am Phosphor gebundenen Organorestes, zum anderen durch die Nucleophilität der Organometallverbindung beeinflußt. Fur die Reaktionsgeschwindigkeit zwischen R2P—PR2 und LiC6H5 bzn. (C6H5)2P—P(C6H5)2 und Organormetallverbindung resultieren folgende Abstufungen: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm R:}\,\,{\rm C}_{\rm 6} {\rm H}_{\rm 5} 〉 {\rm CH}_{\rm 3} 〉 {\rm C}_{\rm 2} {\rm H}_{\rm 5} 〉 {\rm n} - {\rm C}_{\rm 3} {\rm H}_{\rm 7} \left({ \gg {\rm c} - {\rm C}_{\rm 6} {\rm H}_{{\rm 11}} } \right) $$\end{document}Organormetallverbindung: LiC2H5 〉 Mg(C2H5)2 〉 Al(C2H5)3 (〉 Pb(C2H5)4).Zum Zwecke eines Vergleiches werden außerdem (C6H5)2N—N(C6H5)2 und (C6H5)2As—As(C6H5)2 mit LiC6H5 umgesetzt, wobei erwartungsgemäß nicht die N—N-, wohl aber die As—As-Bindung gespalten wird.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280104
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  • 92
    Digitale Medien
    Digitale Medien
    Alkali-Phosphorverbindungen und ihr reaktives Verhalten. XXII. Reaktionen der Alkali-phosphide MPR2 mit tertiären Phosphinoxiden (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 69-78 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Tertiary phosphine oxides react with alkaliphosphides in 1:1 ratio yielding addition compounds {R3PO · MPR′2} which are hydrolytically cleaved into MOH, R3PO and R′2PH. In the case of the Li addition compound, the reaction with HI results in the formation cf R′2PH and adducts of R3PO with LiI. The latter may also be prepared from LiI and R3PO. In dioxane,{R3PO · MPR′2} gives coloured solutions changing from dark red to yellow, depending from R and R′, respectively.
    Notizen: Tert. Phosphinoxide reagieren mit Alkali-phosphiden im Verhältnis von 1:1 unter Bildung von Additionsverbindungen der allgemeinen Formel {R3PO · MPR′2}. Diese liefern bei der Hydrolyse neben Alkalilauge Phosphinoxide und sek. Phosphine. Mit Jodwasserstoff entstehen aus der Lithiumverbindung sek. Phosphine und Additionsverbindungen der Phosphinoxide mit Lithiumjodid. Letztere bilden sich auch aus LiJ und R3PO, wobei in Abhängigkeit von den Ausgangsmengen die farblosen Addukte {R3PO · LiJ} bzw. {(R3PO)4 · LiJ} resultieren.Je nach Organorest R bzw. R′ bilden die Addukte {R3PO · MPR′2} in Dioxan oder Äther dunkelrote bis gelbe Farblösungen. Als Ursache hierfür ist die durch das Lösungsmittel begünstigte polare Form - {R3PO · MPR′2} ⇄ [R3POM⊕][|P̄R′2]⊖ - und damit die Ausbildung eines Phosphidanions [|P̄R′2]⊖ anzusehen.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280107
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  • 93
    Digitale Medien
    Digitale Medien
    Alkalitrimethylsilanolate (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 105-112 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: From the reaction of trimethyl silanole with elementary rubidium and caesium, quantitative yields of the new compounds rubidium and caesium trimethylsilanolate have been obtained. Physical and chemical properties as well as IR and NMR spectra of the alkali trimethylsilanolates being now completed are reported and discussed.
    Notizen: Durch Umsetzung von elementarem Rubidium und Caesium mit Trimethylsilanol wurden erstmals ein Rubidium- bzw. Caesiumtrimethylsilanolat in reiner Form dargestellt. Neben einer vergleichenden Betrachtung ihrer physikalischen und chemischen Eigenschaften wurden an den Verbindungen der auf diese Weise vervollständigten Reihe der Alkali-trimethylsilanolate IR- und NMR-spektroskopische Untersuchungen durchgeführt. Die Ergebnisse werden in Hinsicht auf die vorliegenden Struktur- und Bindungsverhältnisse diskutiert.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280110
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  • 94
    Digitale Medien
    Digitale Medien
    Zur Kenntnis der Imido-diphosphonsäuren und ihrer Derivate. III. Die Reaktion zwischen S4N4 und Phenyldichlorphosphin (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 328 (1964), S. 165-171 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Tetrasulfur tetranitride, S4N4, and phenyldichlorophosphine, C6H5PCl2, react to form salt-like products which can be designated as the chlorides of imido-diphenyl-diphosphonic acid and of higher imido-polyphosphonic acids. Along with these, phenyl-dichlorophosphine sulfide and the trichloride of thio-imido-diphenyl-diphosphonic acid are formed.
    Notizen: Tetraschwefeltetranitrid, S4N4, und Phenyldichlorphosphin, C6H5PCl2, reagieren zu salzartigen Produkten, die als Chloride der Imido-diphenyl-diphosphonsäure und höherer Imido-polyphosphonsäuren beschrieben werden können. Daneben entstehen Phenyldichlorphosphinsulfid und das Trichlorid der Thio-imido-diphenyldiphosphonsäure.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643280307
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  • 95
    Digitale Medien
    Digitale Medien
    Beiträge zur Thermochemie der Hydrate. II. Der thermische Abbau von MgSO4·7 H2O, NiSO4·7 H2O, ZnSO4·7 H2O (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 331 (1964), S. 1-6 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: By decomposition at 20 torr the following hydrate phases are indicated: MgSO4 · 7 H2O, MgSO4 · 6 H2O, MgSO4 · 4 H2O, MgSO4 · 2 H2O, MgSO4 · 1 H2O, MgSO4, NiSO4 · 7 H2O, NiSO4 · 6 H2O, NiSO4 · 4 H2O, NiSO4 · 2 H2O, NiSO4 · 1 H2O, NiSO4; ZnSO4 · 7 H2O, ZnSO4 · 1 H2O, ZnSO4.
    Notizen: Durch isobaren Abbau bei 20 Torr können folgende Hydratphasen nachgewiesen werden: MgSO4 · 7 H2O, MgSO4 · 6 H2O, MgSO4 · 4 H2O, MgSO4 · 2 H2O, MgSO4 · 1 H2O, MgSO4, NiSO4 · 7 H2O, NiSO4 · 6 H2O, NiSO4 · 4 H2O, NiSO4 · 2 H2O, NiSO4 · 1 H2O, NiSO4; ZnSO4 · 7 H2O, ZnSO4 · 1 H2O, ZnSO4.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643310102
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  • 96
    Digitale Medien
    Digitale Medien
    Silane. VII. Saure Solvolyse von halogensubstituierten Trimethylsilanen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 331 (1964), S. 59-62 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The acid-catalysed solvolysis of (CH3)2(CH2X)SiH [X = Cl, Br, J], (CH3)2(CHX2)SiH [X = Cl] und (CH3)(CH2X)SiH [X = Cl] was determined in ethanol/water and the influence of substituents was compared by means of TAFTs constants σ*.
    Notizen: Die säurekatalysierte Solvolyse von (CH3)2(CH2X)SiH [X = Cl, Br, J], (CH3)2(CHX2)SiH [X = Cl] und (CH3)(CH2X)SiH [X = Cl] wurde in Äthanol/Wasser gemessen und der Substituenteneinfluß mit den TAFT-Konstanten σ* verglichen.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643310110
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  • 97
    Digitale Medien
    Digitale Medien
    Zur Frage der Existenz einer Peroxoschwefligen Säure H2SO4 und einer Peroxoselenigen Säure H2SeO4 (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 331 (1964), S. 92-97 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: The sulfuric-acid isomer peroxosulfurous acid, H2SIVO4, and its derivatives are rearranged to the much more stable sulfuric acid after their intermediate formation in the course of different reactions. Peroxoselenous acid, H2SeIVO4, on the other hand, may be prepared from SeO2 or H2SeO3 and H2O2.
    Notizen: Die zur Schwefelsäure isomere Peroxoschweflige Säure H2SIVO4, und ihre Derivate lagern sich nach ihrer Bildung bei verschiedenen Umsetzungen so rasch in die erheblich stabilere Schwefelsäure um, daß sie nicht isoliert werden können. Demgegenüber kann die peroxoselenige Säure H2SeIVO4, wenn auch noch nicht in reiner Form, aus SeO2 bzw. H2SeO3, und H2O2, dargestellt werden.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643310114
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  • 98
    Digitale Medien
    Digitale Medien
    Stabilitätsmessungen an Komplexen des N-(β-Hydroxy -äthyl)-β-alanins und verwandter Verbindungen (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 331 (1964), S. 112-120 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: N-(β-Hydroxy-ethyl)-β-alanine (III), 2-(β-hydroxy-ethylamino)-terephathalic acid (IV) and 2,5-bis-(β-hydroxy-ethylamino)-terephathalic acid (V) behave as tridentate ligands against Cu(II), Ni(II) and Co(II) ions forming 1,1 and 1,2 complexes, some of which occur in the protonated form. The stability constants of the 1,2 chelates were found to be smaller than those of the 1,1 chelates. The aliphatic ligand III yields more instable complexes than the aromatic compounds IV and V.
    Notizen: N-(β-Hydroxy-äthyl)-β-alanin (III), 2-(β-Hydroxy-äthylamino)-terephthalsäure (IV) und 2,5-Bis-(β-hydroxy-äthylamino)-terephthalsäure (V) wirken Kupfer(II)-, Nickel(II)- und Kobalt(II)-Ionen gegenüber als dreizählige Liganden. Die Stabilitätskonstanten der 1,1-Komplexe, die zum Teil noch Wasserstoffionen anlagern können, wurden bestimmt. In einigen Fällen gelang auch die Ermittlung der Stabilitätskonstanten von 1,2-Chelaten. Sie sind in jedem Fall kleiner als die der 1,1-Chelate. Der aliphatische Ligand III bildet vergleichsweise instabilere Komplexe als die aromatischen Liganden IV und V.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643310117
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  • 99
    Digitale Medien
    Digitale Medien
    Zur photometrischen Zinn-Bestimmung mit Kakothelin (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 331 (1964), S. 151-153 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: A method for the photometric determination of tin in organostannanes is described.
    Notizen: Es wird eine Methode zur photometrischen Sn-Bestimmung in Organostannanen angegeben.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643310306
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  • 100
    Digitale Medien
    Digitale Medien
    Formation of Complex Compounds between Uranyl Nitrate and the Nitrates of the First Group Elements. II. The System: Rubidium Nitrate - Uranyl Nitrate - Water (Conductivity, Refractive Index, Colorimetry and pH) (1964)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 331 (1964), S. 216-219 
    Details
    ISSN: 0044-2313
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Aus der Abhängigkeit des Brechungsindex, der Lichtabsorption, der Leitfähigkeit und des pH-Wertes von der Zusammensetzung gemischter Uranyl- und Rubidiumnitrat-Lösungen wird die Bildung von Tri-, Tetra- und Pentanitratouranyl-Komplexionen gefolgert.
    Notizen: Refractive index, colorimetry, conductivity and pH measurements of a series of mixed solutions of uranyl nitrate and rubidium nitrate have shown the existence of three complex compounds in solution in the (1:1), (1:2) and (1:3) molecular ratios respectively viz. All the above mentioned compounds have been detected only in the solution by the breaks in the usual curves when various properties like conductivity, refractive index, colorimetry and pH were plotted against the m. l. of rubidium nitrate (M/20) added to a fixed volume of uranyl nitrate (M/20).
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/zaac.19643310313
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