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Biomedical subjects

C Voss

Publications and source records attributed to C Voss.

At least 37 records · Page 2Linked to original sources
PubMed1988

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↗
PubMed1988

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↗
PubMed1988

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↗
PubMed1988

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↗
PubMed1986

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↗
PubMed1985

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↗
PubMed1983

Synthesis of the protected tridecapeptide (56-68) of the VH domain of mouse myeloma immunoglobulin M603 and its reattachment to resin supports.

A protected tridecapeptide, representing a new peptide corresponding to residues 56-68 of the VH domain in the mouse M603 myeloma protein, has been prepared by solid phase peptide synthesis. The protected tridecapeptide was prepared using the photolabile 4-bromomethyl-(3-nitro)-benzamidomethyl-resin and the multidetachable 2-[4-bromomethyl)phenylacetoxy]propionyl-resin as solid supports. The synthetic protocol and protecting groups were the same for both syntheses. The protected tridecapeptide was removed photolytically from both supports and the sequence integrity was determined by preview analysis using the solid phase Edman degradation procedure. The protected tridecapeptide-OMPA was purified to homogeneity by DMF/H2O precipitation and LH-60 chromatography. The purity of the protected peptide was further demonstrated by high pressure liquid chromatography on the free peptide after HF deprotection. The protected tridecapeptide was reattached to 4-bromomethyl-(3-nitro)-benzamidomethyl-resin to give the photolabile Boc-(protected)peptidyl-4-oxymethyl-(3-nitro)benzamidomethyl-resin in 25% yield. The protected tridecapeptide-oxymethylphenylacetic acid derivative was reattached to aminomethyl-resin to give Boc-(protected)peptidyl-2-[4-oxymethyl)phenyl]acetamidomethyl-resin in 45% yield and to 2-bromopropionyl-resin generating the multidetachable Boc-(protected)peptidyl-2-[(4-oxymethyl)phenylacetoxy] propionyl-resin in 80% yield. The reactivity of these reattached peptides was demonstrated by the quantitative coupling of Boc-leucine to the protected peptide-resin. The advantages and disadvantages of the different resins with respect to solid phase fragment synthesis are discussed.

Amino Acid Sequence↗
PubMed1982

[Serum cholesterol and liver deiodase activity in rats of different body composition after low or high fat diet. Effect of a feeding change in fat-rich to fat-poor diet and the reverse or of an iodine deficient diet].

Male Wistar rats with an average age of 28 weeks received diets high (HFD: 50% fat) or low (LFD: 3% fat) in fat content. Rats were restricted on iodine intake by feeding pure diets without iodine addition. The relative degree of iodine shortage of rats was estimated by 131I-uptake. PB131I and ETR. Serum cholesterol, whole body lipid content and liver deiodinase activity of LFD (control)- and HFD-rats were analyzed. A change of diet feeding from high to low fat content and vice versa took place to discriminate the effect of diet fat from body fat content of rats on serum cholesterol and deiodinase activity. HFD fed rats with high body fat content showed at iodine restriction the same serum cholesterol concentration as relative lean LFD-animals. Post feeding change from diet rich to poor on fat and vice versa at 4 weeks the obese animals have lost body fat only 10-20% at calorie restriction and exhibit higher serum cholesterol levels and equal liver deiodinase activity as lean, now fat rich fed control animals. Heavy HFD-rats fed on fat rich diet for 22 weeks have approximately two times higher liver lipid content as light LFD-animals. Because liver lipid content and deiodinase activity between light LFD- and heavy HFD-rats before and after change of diet feeding are equal, a relation between liver lipid content and enzyme activity is discussed.

Animals↗
PubMed1981

[Body composition of light and heavy rats in a high or low fat diet group].

The authors studied the body composition of light and heavy male Wistar rats (approximately 11 and 21 weeks of age) from two diet groups fed a high-fat (HFD, 50 per cent (w/w) fat) and a low-fat diet (LFD, 3 per cent (w/w) fat), respectively. In both age-groups the heavy HFD rats showed a considerably higher fat proportion (as compared with light LFD rats) associated with a correspondingly reduced body water content and an approximately identical body protein concentration. On comparing light and heavy rats (11 and 21 weeks of age) from the same diet group as to their body composition, the authors found greater differences only in the 21-week-old HFD animals; as against light animals, the heavy animals exhibited a highly significant increase in body fat content and a highly significant decrease in body water content. A comparison of LFD and HFD animals of approximately the same weight revealed an increase of the relative body fat content and a decrease of the percentage of body water content in light 11-week-old and also in 21-week-old HFD animals as against heavy LFD animals.

Age Factors↗
PubMed1981

[Effect of high-fat diet on the contents of total cholesterol, free cholesterol and esterified cholesterol in the serum and liver of rats].

Four-week-old male Wister Rats were fed a diet containing 50% of fat up to the age of 9 weeks and 6 months, respectively. The control group received a diet with 3% of fat. The fat consisted of lard (1/3) and sunflower oil (2/3). Serum cholesterol was determined according to the standard method 1 of the DAB 7 (German Pharmacopoeia); liver cholesterol was estimated by the method of Naito and Lewis. As compared to the control animals, the 9-week-old rats on the high-fat diet showed serum cholesterol values (total, free and esterified cholesterol) which were significantly lower. There was no difference in serum cholesterol level between the 6-month-old rats on the high-fat diet and the control animals. In contrast to this, the liver cholesterol levels of the 9-week-old and the 6-month-old rats on the high-fat diet were significantly increased. In both age-groups the ratio of free cholesterol to esterified cholesterol was changed in favour of the esterified cholesterol. The present results confirm the findings reported in the literature, except for the unchanged serum cholesterol values observed by the authors in the long-time dietary experiment.

Animals↗
PubMed1981

Synthetic insulin by selective disulfide briding, II. Polymer phase synthesis of the human B chain fragments.

Five protected fragments Ddz-Phe-Val-Asn(Mbh)-Gln(Mbh)-His(Dnp)-Leu-Cys(Acm)-Gly-OH [I], Ddz-Ser(But)-His(Dnp)-Leu-Val-Glu-(OBut)-Ala-OH [II], Ddz-Leu-Tyr(But)-Leu-Val-Cys(Mbzl)-Gly-OH [III], Ddz-Glu(OBut)-Arg(Tos)-Gly-OH [IV], Ddz-Phe-Phe-Tyr(But)-thr(But)-Pro-Lys(Z)-Thr(But)-OH [V] for the synthesis of the human insulin B chain, were prepared by an efficient procedure on solid phase.

Disulfides↗
PubMed1981

[Effectors and products of enzymatic diiodotyrosine deiodination by a plasmatic fraction from pig liver].

Effectors and products of enzymatic diiodotyrosine (DIT) deiodination by a cytosolic fraction of pig liver hab been investigated. 13% of the degraded 131I-DIT was found as monoiodotyrosine by thin layer chromatography. The main quantity of the deiodinated DIT was found on the start point of the chromatogram bound to enzyme protein. Tyrosine as a reaction product of enzymatic deiodination of [14C]-IT could not be identified exactly. The liver cytosolic deiodinase is activated by pyruvate; the extent of activation depends on th pyruvate concentration. Diiodohydroxyphenylpyruvate as a product of transamination and theoretically possible intermediate product could be excluded. NADPH 2 and sodium dithionite activated the deiodinase to 1/3, sodium dithionite together with FAD to 1/2 the amount of which was determined for the action of pyruvate. The enzymatic activity in the presence of pyruvate and NADPH2, respectively NADPH2/FAD is identical with the sum of the single activities. The effect of dithionite and sulfite on deiodinase activity depends on the concentration: low effector concentrations increase, while high concentrations decrease the enzyme activity. The liver plasma deiodinase was inactivate quantitatively by reaction with 10(-4) M PCMB; by reaction with 10(-4) M DTNB or NEM the inactivation was 40% only. The inactivation of deiodinase by PCMB was quantitative reversible by cysteine, while inactivation by DTNB was reversible by cysteine to maximal 70% only. Differences between cytosolic and microsomal deiodinases are discussed also in regard to the mechanism of DIT-deiodination by a liver cytosolic fraction with direct participation of SH-groups.

Animals↗
PubMed1980

[Cholesterol esterification in the serum of hypothyroid rats].

The ratio of unesterified to total serum cholesterol in hypothyreotic rats has been studied. Extreme rat hypothyreosis of identical degree was induced by radiothyroidectomy (group R-HT) and feeding of thyreostatics (groups MTU-HT and MMI-HT). Determination of total serum cholesterol content and the unesterified cholesterol content resulted in following changes (all changes significant for p < 0,001): 1. Higher total cholesterol in hypothyreotic rats 4 and 7 weeks after beginning the experiments as compared to the controls. 2. The ratio of unesterified cholesterol to total cholesterol was increased in all hypothyreotic groups. It is discussed, that the esterification reaction in serum catalyzed by the lecithin-cholesterol-acyltransferase (LCAT) is diminished in the hypothyreotic state.

Animals↗
PubMed1980

Morphology and distribution of the synapses to the spinal motoneuron of the frog.

The quantitative distribution of the different structural elements on the surface of the motoneurons (MN) in the spinal cord of the frog was studied in thin sections and freeze-fracture replicas. In particular, the different synaptic types and their distribution on the MN soma and dendrites are described. In thin sections three types of synapses were discerned: the S-type with spherical vesicles, the F-type with flattened vesicles, and finally the C-type synapse with spherical vesicles and a subsynaptic cistern. The synaptic covering at the MN surface as determined by thin sections is about 36%. In freeze-fracture replicas were observed boutons with and without gap junctions, and C-type boutons. When using the latter technique the synaptic covering was found to be 43%. With both techniques special attention was paied to the morphology of the C-type bouton and both the subsynaptic and extrasynaptic cisterns. The soma membrane over the sub- and extrasynaptic cisterns reveals characteristic and very similar morphological features with respect to both the distribution and size of the membrane particles. the possible functions of the two cisternal types are discussed.

Animals↗