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Biomedical subjects

J Schulze

Publications and source records attributed to J Schulze.

At least 127 records · Page 7Linked to original sources
PubMed1986

[Cardiologic findings in newly manifested type II diabetics of the diabetes intervention study].

In 1,126 newly manifested primarily purely dietetic manageable type II-diabetics (628 men, 498 women) of the diabetes intervention study (DIS) at the age from 30 to 55 years the prevalence of the ischaemic heart disease was established with the help of the ECG in rest (Minnesota code) and in 70% of the test persons by an additional electrocardiography after work. Including the two parameters in 9.2% of the diabetic men and 26.1% of the women electrocardiographic findings of an ischaemic heart disease could be proved. The proportion of pathological findings of the ECG increased with age. While the proportion of a probable ischaemic heart disease (code 1.1-1.2) in the ECG in rest and with 1.4% the same size in the two sexes, in women, the percentage of a possible ischaemic heart disease (code 1.3, 4.1-4.3/5-5.3/8.3) prevailed with statistical significance after the 45th year of age. The at present numerically largest study on newly detected diabetics of type II gives evidences to the previous cardial lesion when the diabetes is manifest at medium age on the basis of the homogeneity of the number of patients.

Adult↗
PubMed1986

Intestinal metabolism of nitrosamines. 1. Transport and metabolism of six nitrosamines in isolated perfused rat small intestinal segments.

Possible relationships between structure and metabolism of nitrosamines have been investigated in the rat small intestine. Isolated segments of jejunum and ileum were perfused from the luminal side for 2 h with a Tyrode solution containing one of four symmetrical dialkylnitrosamines with 2-5 carbon atoms per side chain, all 14C-labeled at the alpha position, or one of two unsymmetrical nitrosamines, N-nitroso-tert-butylmethylamine and N-nitrosomethylbenzylamine, 14C-labeled in the methyl group. Besides measurement of 14CO2 production and covalent binding of 14C to intestinal tissue, the absorbed fluid (absorbate) as well as the perfusion medium and tissue homogenates were analysed by h.p.l.c. for the presence of polar metabolites to assess the intestinal metabolism of nitrosamines. Neither N-nitrosodiethylamine nor the two unsymmetrical nitrosamines were metabolized to any significant extent. With increasing chain length of symmetrical dialkylnitrosamines small intestinal metabolism increased dramatically. At a concentration of 1 microM up to 60% and 30% of N-nitrosodipropylamine (NDPA) in jejunal and ileal segments, respectively, and greater than 90% of N-nitrosodibutylamine (NDBA) and N-nitrosodipentylamine (NDAA) in both intestinal segments were metabolized during absorption. Metabolites were found also in perfusate and tissue homogenate but generally at lower percentages as compared with the absorbate. With increasing concentrations the percentage of metabolites decreased, the decrease being more pronounced in ileal as compared with jejunal segments. CO2 production and covalent binding were negligible in ileal segments but amounted up to 5-8% and 0.1-0.4% of the dose in jejunal segments perfused with NDPA, NDBA or NDAA. With NDBA and NDAA no concentration-dependent decrease could be observed, the highest amounts of 14CO2 and bound 14C being found at intermediate concentrations. At concentrations below 10 microM metabolic pathways other than alpha-hydroxylation seem to be of greater importance. The toxicological evaluation of the high intestinal first-pass metabolism of NDPA, NDBA and NDAA must await the identification and quantitation of the metabolites formed.

Animals↗
PubMed1986

Composition of diesel exhaust with particular reference to particle bound organics including formation of artifacts.

For particulate emissions, standards were established by the US EPA in February 1980. Regulations limiting particulates from new light duty diesel vehicles are valid by model year 1982. The corresponding standards on a pure mass basis do not take into account any chemical character of the diesel particulate matter. Our investigation of the material composition shows that diesel particulates consist mainly of soot (up to 80% by weight) and adsorptively bound organics including polycyclic aromatic hydrocarbons (PAH). The qualitative and quantitative nature of hydrocarbon compounds associated with the particulates is dependent not only on the combustion parameters of the engine but also to an important degree on the sampling conditions when the particulates are collected (dilution ratio, temperature, filter material, sampling time etc.). Various methods for the analyses of PAH and their oxy- and nitro-derivatives are described including sampling, extraction, fractionation and chemical analysis. Quantitative comparison of PAH, nitro-PAH and oxy-PAH from different engines are given. For assessing mutagenicity of particulate matter, short-term biological tests are widely used. These biological tests often need a great amount of particulate matter requiring prolonged filter sampling times. Since it is well known that facile PAH oxidation can take place under the conditions used for sampling and analysis, the question rises if these PAH-derivates found in particle extracts partly or totally are produced during sampling (artifacts). Various results concerning nitro- and oxy-PAH are presented characterizing artifact formation as a minor problem under the conditions of the Federal Test Procedure. But results show that under other sampling conditions, e.g. electrostatic precipitation, higher NO2-concentrations and longer sampling times, artifact formation can become a bigger problem. The more stringent particulate standard of 0.2 g/mi for model years 1986 and 1987 respectively requires particulate trap technology. Preliminary investigations of the efficiency of ceramic filters used reveal that the reduction of the adsorptively bound organics is lower than the decrease of the solid carbonaceous fractions.

Aldehydes↗
PubMed1985

The metabolism of some xenobiotics in germ-free and conventional rats.

The different participation of the gastrointestinal microflora in the biotransformation of gamma-hexachlorcyclohexane (gamma-HCH), azobenzene and the isolated glucosinolate progoitrin was studied. Marked dehydrochlorination of gamma-HCH to gamma-pentachlorcyclohexene (PCCH) also occurs without participation of the microflora. Azobenzene was reduced in germ-free (g) and conventional (c) rats to hydrazobenzene but was split to aniline only in c-rats. Progoitrin was split with and without the influence of the microflora, but the splitting was more complete in rats with intact gastrointestinal flora.

Animals↗
PubMed1985

Catabolic pathways for high-dosed L(-)- or D(+)-carnitine in germ-free rats?

Gnotobiotic rats received up to 3 mmol L-carnitine/day with the drinking water during 9 days. They excreted about a quarter of the administered dose with the urine, partially in form of acetyl-L-carnitine, but trimethylamine, trimethylamine N-oxide or gamma-butyrobetaine were not detectable in urine or faeces in contrast to conventional animals. After oral loading with D-carnitine the unphysiological isomer was absorbed and either excreted unchanged in urine or metabolized to acetonyltrimethylammonium. With regard to the development of carnitine deficiency syndromes and the degradation of nutritional carnitine the conclusion has to be drawn, that the bacteria of the gastro-intestinal tract, but not the tissues of the mammals, are responsible for the metabolization of L-carnitine to gamma-butyrobetaine or trimethylamine.

Acetylcarnitine↗
PubMed1984

[The pre- and postoperative nutritive maintenance of rats with enterostomata].

The repercussion of nutrition on the food behaviour, bowel function and body mass development of rats with ileostomata and colostomata has been studied during the perioperative phase. An and libitum feeding until immediately before the operation has been found to be beneficial. The postoperative dietetic regimen is of decisive importance to the survival of the animals operated on. The best postoperative development was achieved in ileostomized rats by a diet rich in nutrients and energy, and low n bulkage. In rats with colostomata, the success of the operation may be impaired by a constipation in the intestinal region before the stoma, which frequently leads to occlusion. A spontaneous evacuation of chyme was induced in these animals only by a high-lactose and low-protein diet. It is recommended to keep the experimental animals on pre- and postoperative diets which take into account the location of the respective enterostoma.

Animals↗
PubMed1984

[The degradation of lactose in the intestines of rats on human and cow's milk diets].

Female lactose adapted rats were kept for 10 days on human milk (HM), a milk diet adapted to human milk (MD1), and a milk diet rich in protein and phosphate (MD2), the lactose supply being always the same. In the caecum, colon and faeces, the pH value, the phosphorus content, the buffer capacity and the numbers of microorganisms with proteolytic activity (Bacteroides, Klebsiella, Proteus) were lower and the lactose concentration and the beta-galactosidase activity were higher on HM and MD1 than on MD2.

Animals↗
PubMed1984

[Use of the gnotobiotic rat for determination of the in vivo activity of Bifidobacterium beta-galactosidase].

Under the conditions of in vitro cultivation, the height of the beta-galactosidase activity of Bifidobacterium spec. is essentially influenced by the composition of the culture medium. The use of gnotobiotic (germ-free and monoassociated with Bifidobacterium longum) rats permitted to differentiate in the chyme between beta-galactosidase activities of mucosal and microbial origin. In germ-free animals, the chyme in the small intestine and the colon contains nearly 10-20% of the activity measured in the mucosa (in each case expressed as g on a wet-weight basis). Monoassociation with B. longum does not affect the lactose-splitting activity of the chyme in the small intestine, but increases the activity of the chyme in the colon to twice the value of the mucosal activity. In the monoassociated animals, feeding of lactose leads to a further multiple increase of the chymal beta-galactosidase activity in the caecum, colon and faeces.

Animals↗
PubMed1984

[Adherence to the gastrointestinal wall and potential pathogenicity of gastrointestinal germs].

Under certain circumstances--invasion of adhesive germs, abundant reproduction of the germs at the mucosa, a lowered resistance of the body--the adhesive flora can become a pathogenic factor itself. All hitherto known researchers point out that, in this connection, adhesions at the small intestinal wall is of main importance, as could be shown by our experiment with gnotobiotic rats, too. From the results of our experiments regarding the adhesion mechanisms, we conclude that the possibilities of prophylaxis and therapy of gastrointestinal disturbances induced by microbial effects could be extended by means of aimed inhibition of such adhesion forces.

Adhesiveness↗
PubMed1984

[The influence of nutrition of Gram-negative anaerobes in the intestinal tract].

Concluding from the hitherto known results regarding nutritive influences on the intestinal microbial population, particularly the gramnegative flora, it was found that the human intestinal flora is maintained mainly by endogenous mechanisms. Furthermore, the postnatal intestinal flora shows a weaker stability than that of adults. Also in the period of infancy, influences on the gut flora are most efficient in case of changes within the milieu (ph EH etc.). Cause and importance of longitudinal alterations within the postnatal intestinal flora are obscure.

Adult↗
PubMed1984

Reduced incidence of cardiovascular complications and mortality in hyperlipoproteinemia (HLP) with effective lipid correction. The Dresden HLP study.

The influence of the efficacy of triglyceride and cholesterol correction on cardiovascular complications and mortality was analysed in a follow-up study with 260 patients with primary HLP (triglycerides before entry greater than 2.9 mmol/l and/or cholesterol greater than 7.8 mmol/l). The follow-up time was 67.4 +/- 27 months. It was hypothesised that reduction of elevated levels of triglycerides and/or cholesterol influenced favourably the incidence of angina pectoris, MI, stroke and total mortality. For ethical reasons, it was not possible to carry out the investigations with a control group. Therefore, we performed an internal comparison of 3 categories of lipid correction achieved during the trial (effective, moderate, insufficient). A substantial improvement of the lipid disorder was obtained by individualizing the therapy. Triglycerides and cholesterol decreased on average by 50% and 20%, respectively. The incidence of MI was 10 times higher than in the general population. With respect to the type of HLP, hypertriglyceridemia revealed a significantly higher incidence of MI compared with hypercholesterolemia and mixed HLP. The therapy variant was only of importance with respect to gallstone diseases accumulating in the CPIB-treated subgroups. We found a majority of cases with newly manifested angina pectoris and stroke in the group with moderate correction of both triglycerides and cholesterol. Patients with effective triglyceride and cholesterol correction suffered less frequently from MI than those with insufficient correction. This was also the case with secondary prevention in cases with MI prior to entry. There was no significant difference in the distribution of lipid categories at entry between those with and without recurrent infarction. In the group without reinfarction, however, the percentage with insufficient control diminished significantly. Associated risk factors such as hypertension, diabetes, smoking and obesity were of minor or no significance. In subjects with effective triglyceride correction, the total mortality was 0.97/1000 treatment months vs. 3.63 in insufficiently treated patients. The figures for MI mortality were 0.36 and 1.91, respectively.

Adolescent↗
PubMed1984

Insulin resistance in diabetics and non-diabetics with impaired triglyceride removal.

Endogenous triglyceride turnover has been measured in patients with normotriglyceridemia or with hypertriglyceridemia using the radioglycerol labelling technique. In parallel, a 50 g oral glucose tolerance test was performed (blood glucose, serum insulin, free fatty acids). Non-diabetics, borderline diabetics, and overt diabetics were included. In the non-diabetics, insulin levels were negatively correlated with fractional catabolic rates for triglycerides, whereas no correlation with triglyceride synthesis rates existed. Patients with low fractional catabolic rates for triglycerides have significantly higher insulin and free fatty acid concentrations, pointing to an association between impairment of triglyceride removal and insulin resistance. There is no typical kinetic pattern of triglyceride metabolism in non-insulin-dependent diabetes mellitus.

Adult↗
PubMed1983

Digestion of maltitol in man, rat, and rabbit.

Maltitol is found to be enzymatically hydrolyzed by the small intestinal mucosa of man, rat, and rabbit and metabolized by everted sacs of rabbit intestine at a moderate rate. On in vivo perfusion of maltitol (15.3 mumol/min) through the small intestine, 19% of the sugar alcohol is digested by gnotobiotic rats. 120 min after stomach intubation of gnotobiotic rats, only 31% of the ingested maltitol is found in the ileum. A daily application of 35 g maltitol to 4 human beings does not influence the parameters of well-being, compatibility and fecal state. It is concluded that maltitol will be digested and utilized by man, rat, and rabbit.

Adult↗