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Biomedical subjects

C Voss

Publications and source records attributed to C Voss.

At least 19 recordsLinked to original sources

New isoflavonoids as inhibitors of porcine 5-lipoxygenase.

The inhibitory activity of new isoflavonoids on 5-lipoxygenase of porcine leukocytes was investigated. Isoflavans (I) proved to be stronger inhibitors than isoflavones (II). The isoflavans containing ortho-hydroxy groups in ring A showed the lowest Ki values (0.8-50 microM). In comparison, isoflavans with meta-dihydroxy groups exhibited Ki values higher than 150 microM. The effect of commercial antioxidants was tested also on porcine 5-lipoxygenase. Butylated hydroxyanisole (Ki: 25 microM) and butylated hydroxytoluene (Ki: 55 microM) revealed moderate inhibitory activity, whereas L-ascorbic acid, L-ascorbyl palmitate, dl-alpha-tocopherol and n-propyl gallate showed weak inhibitory activities (Ki: 100-260 microM).

Animals

In vitro effect of vanadate on content, secretion and biosynthesis of insulin in isolated islets of normal Wistar rats.

In in vitro experiments the effect of (Na-ortho)vanadate (1-50 mumol/l) on content, secretion and biosynthesis of insulin was investigated in isolated islets of normal Wistar rats. Compared with controls insulin content is unchanged, but insulin secretion and biosynthesis rate are significantly reduced; secretion is significantly more reduced in the basal than in the stimulating glucose medium. Our results support the view that vanadate exhibits its influence on insulin metabolism in the beta cell already.

Animals

Streptozotocin diabetes in spontaneously hypertensive rats.

The aim of our experiments was to find out to what extent male spontaneously hypertensive (SH) as well as normotensive Wistar-Kyoto (WKY) and Wistar-Schönerlinde (WS) rats developed changes of the endocrine pancreas function in response to streptozotocin (SR). 4 week old WS, WKY and SH rats were given ip. injections of 70 or 100 mg SR/kg and were killed at an age of 8 weeks, after which blood glucose, and in isolated islets, insulin-leakage, insulin secretion and insulin biosynthesis were determined; histologically the relative volume density of islet tissue was estimated. The results demonstrated that the intensity of the SR-caused damage to the endocrine pancreas differs considerably in the three strains of rats. The damage increases in the order WS, WKY, SH rats. These findings are indicative of the role played by genetic predisposition and of an increase in damage to the endocrine pancreas due to hypertension.

Animals

Imipramine treatment for chronic depression.

Antidepressant drugs in the treatment of chronic depressions have received little systematic study. We used a two-week, single-blind placebo washout followed by a six-week, double-blind comparison of imipramine hydrochloride and placebo in a sample of 76 outpatients with DSM-III dysthymic disorder entered into a trial at two centers. Subjects were preponderantly female, had insidious onset at an early age, and had depressions of moderate severity; 96% also met the DSM-III criteria for major depressive disorder at the time of presentation. Sixty percent had a history of persistent depressive symptoms sufficient to meet criteria for major depression for longer than two years. Markedly favorable responses occurred in 45% of imipramine-treated (n = 29) and 12% of placebo-treated (n = 25) patients and, respectively, 59% and 13% of those who completed the study. Imipramine produced significant advantage in measures of depressive symptoms, global severity of illness, and self-rated social and vocational function. Recovered patients experienced remission from both long-standing symptoms and deficits as well as more recently exacerbated aspects of their syndrome. Patients with pure dysthymic disorder of a mild, subsyndromal type were uncommon in these clinical settings. However, anti-depressant medication was effective for many moderately severe chronic depressions, which had previously been untreated or undertreated, presumably related to misdiagnosis.

Adult

No diabetogenic effect of N-nitrosomethylurea on pregnant BALB/c mice and their progeny.

Our studies give evidence that N-nitrosomethylurea applied to BALB/c mice one day before or after mating or during pregnancy (12th day) even in small (16 or 32 mg/kg) and repeated doses (16 mg/kg on 5 consecutive days, total dose 80 mg/kg) is a more toxic than potent diabetogenic agent. Mortality rises in parent mice and their progeny with no influence on glucose tolerance test and blood glucose level over the whole investigation period (4 hours-12 weeks).

Animals

Diabetogenic effects of N-nitrosomethylurea in rats.

The influence of a single i.v. injection of 75 or 175 mg N-nitrosomethylurea (NMU)/kg into Wistar rats on plasma glucose, i.p. glucose tolerance, plasma insulin and glucagon, glucose stimulated insulin secretion and release as well as on the biosynthesis of insulin in isolated pancreatic islets have been investigated at set intervals between the 3rd day and the 6th week post injectionem. At the end of the experimental period all NMU-treated animals were alive but had significantly reduced body mass. All animals remained normoglycemic even after the glucose load. 3 days after drug application plasma insulin decreased only insignificantly in the 175 mg NMU-group, whereas plasma glucagon was significantly reduced in both drug-groups; after 3 and 6 weeks the reduction of plasma glucagon was still about 30 percent. In isolated islets the glucose stimulated insulin secretion, the percent stimulation of insulin release and insulin biosynthesis were significantly decreased.

Animals

Effect of streptozotocin on transaminases, creatinine and urea in serum of rats.

This study investigates the diabetes-induced lesions in liver and kidney and in addition the possible side effects of the diabetogenic substance streptozotocin (SR) on these organs in non-diabetic animals. 5-week-old female Wistar rats were injected 65 or 130 mg SR/kg body mass. Some animals of the drug group did not become hyperglycemic; thus it was possible to separate the drug effect from the diabetic influence on liver and kidney. In serum investigations some metabolic changes concerning the activities of the liver enzymes aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and the concentrations of urea and creatinine up to 30 days after drug application were studied. SR in hyperglycemic animals causes a time and dose dependent rise in all investigated parameters. Also in normoglycemic rats a significant increase in alkaline phosphatase and in creatinine was observed after 10 days. After 21 and 30 days there were no differences compared to untreated control rats, whereas elevated levels were observed in the hyperglycemic rats. Thus our results support the view of a short damaging effect of SR on liver and kidney without inducing a diabetic state; in hyperglycemic rats the damaging effect is more pronounced.

Alanine Transaminase

Imipramine and social-vocational adjustment in chronic depression.

The authors compared the effects of 6 weeks of imipramine treatment with 6 weeks of placebo treatment on social and vocational impairment in chronic depression. Imipramine was associated with significantly greater pre- to posttreatment improvement of social-vocational impairments in chronic depression, suggesting that these impairments may have represented affective symptoms rather than characterologic deficits.

Adult

Temperature preference of drinking water in rats.

The water temperature preference of adult male albino rats was studied. Deprived and normally hydrated animals were exposed at peak hours of consumption to a choice between 12 degrees C and 30 degrees C water or to 12 degrees C and 34 degrees C water. Food intake was not restricted. There was a clear preference for the warmer water. It is concluded that oropharyngeal temperature cues influence water intake.

Animals

Distribution of 125I-thyroxine in different organs and tissues of dietically obese rats.

The distribution of 125I-thyroxine (% dose/g tissue; tissue/plasma radioactivity ratio) was investigated in different tissues of 28-week-old obese Wistar rats. Obesity was induced by high-fat diet (HFD) and confirmed by carcass analysis; in heavy obese animals the relative and absolute fat content is increased twofold and threefold, respectively, compared to control rats fed on a low-fat diet (LFD). Heavy HFD rats exhibit diminished 125I-T4 distribution in the "slow pool" (fat tissue, muscle) and unchanged values in the "fast pool" (liver, kidney) in comparison with LFD rats with low body weight. The differences in distribution presented here are not caused by the diet per se, but they are the consequence of the obesity of the animal, because no differences in the 125I-T4 distribution were found in the 125I-T4 between HFD and LFD rats with relatively equal body weight and body composition. The reduced T4 distribution in the fat tissue of obese rats is discussed in connection with possibly decreased lipolysis in this tissue and possible causal participation in the beginning of obesity.

Adipose Tissue

[Effect of diet and L-thyroxine on deiodination of L-thyroxine in rat liver].

Male Wistar rats on 3 or 50% fat diet for 14 weeks were treated during 6 weeks with L-thyroxine (5 or 25 or 50 microgram 100 g body weight/2 times weekly, sc.) and the activity of L-thyroxine-deiodinase was determined in supernatans of liver homogenates. With increasing thyroxine lading the deiodinating activity increases statistically significantly within each diet group. The liver of animals on 50% fat diet deiodinates increasing thyroxine doses to a lesser extent than livers of animals on 3% fat diet. It is discussed that high fat diet influences thyroid function and that thyroxine shares effectiveness and undergoes deiodination also in other tissues, probably in fat tissue, to a higher extent.

Animals

[The determination of the red cell isoenzymes 6-phosphogluconate dehydrogenase (E.C.1.1.1.44) and acid phosphatase (E.C.3.1.3.2) by means of agarosegel thinlayer electrophoresis (author's transl)].

Methods for the determination of the red cell isoenzymes 6-PGD and acP by means of agarosegel thinlayer electrophoresis are referred. Using these relatively simple techniques, results can be obtained after at least two hours. The quality of separation in both systems is higher than that obtained after starch gel electrophoresis.

Acid Phosphatase

[Properties of adipocytes (diameter, volume, triglyceride content, cell number) of certain types of fatty tissue as a function of age in male Wistar rats].

The diameter, volume, triglyceride content and number of adipocytes were determined in male Wistar rats at the age of 6 weeks and 2, 3, 12 and 18 months, respectively. A standard diet and water were given ad libitum. The adipocytes were isolated by means of the method of RODBELL. The weight and fat content of the fatty tissues were determined gravimetrically. Age exerts no effect on the adipocyte parameter, nor on the weight and the fat content of the fatty tissue. In contrast to this, there are relationships between adipocyte diameter and the increases in body weight. In all age groups, the increase in size and number of the adipocytes was significantly greater in heavy animals than in light ones. Genetic, hormonal and dietarily-induced factors are discussed as a possible cause. The authors observed no difference in adipocyte size between epididymal and perirenal fatty tissues. As compared to this, the mesenteric adipocytes were smaller.

Adipose Tissue

[Effect of a high fat diet on the behavior of the diameter, volume, triglyceride content and number of the adipocytes in different types of fatty tissues in male Wistar rats].

The effect of a high-fat diet on the diameter, volume, triglyceride content and number of the adipocytes was studied in male Wistar rats at the age of 9 weeks and 6 months, respectively. The adipocytes were isolated by means of the method of RODBELL. The adipocyte diameters were measured using the microscopic method. The weight and the fat content of the fatty tissue were determined gravimetrically. A diet containing 50% fat increases the diameter, volume and triglyceride content of the adipocytes and also the weight and the fat content of the different types of fatty tissue. The fat content of the diet and the duration of feeding are of importance. The high-fat diet exerts no effect on the adipocyte number. However, in both age groups, the adipocyte numbers were sometimes greater in heavy animals than in light ones fed the same diet. Genetic, hormonal, and dietarily-induced factors are considered as a possible cause.

Adipose Tissue

[Dietary proteins and deiodination in the liver].

The authors studied in male Wistar rats the effects of diets containing 66 and 2% (w/w) of protein on the one hand, and 18% (w/w) of protein on the other hand, on the deiodination of L-thyroxine in liver homogenate supernatants. The deiodase activity in the liver protein increased in case of low-protein diet, and decreased in case of high-protein diet; these differences were statistically significant. When the body weights of the animals were taken into account, the deiodinating power of the whole liver was significantly reduced in case of low-protein diet, but not significantly reduced in case of high-protein diet. Consequently, the reference value adopted for the calculation of the degree of deiodination is of paramount importance to validity.

Animals