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Biomedical subjects

G Steiner

Publications and source records attributed to G Steiner.

At least 307 records · Page 17Linked to original sources
PubMed1975

Production of chylomicron-like lipoproteins from endogenous lipid by the intestine and liver of diabetic dogs.

Pancreatectomized dogs developed hypertriglyceridemia. This probably resulted from a lack of insulin rather than a lack of glucagon, as it did not develop either in pancreatectomized dogs maintained on insulin, or in dogs with all but the uncinate process of the pancreas removed. The increase in plasma triglycerides was preceded by a decrease in post-heparin lipolytic activity (PHLA) and an increase in FFA. As the hypertriglyceridemia developed in fasted dogs who had previously been on fat-free diets, the triglyceride fatty acids (TGFA) were nondietary. These endogenous TGFA originated from adipose tissue rather than from de novo synthesis. The composition of the lipoprotein TGFA was identical to that of adipose tissue. Furthermore, nicotinic acid blocked the FFA increase and the development of the hypertriglyceridemia. However, it did not prevent the fall of PHLA. Although their TGFA were entirely nondietary, the lipoproteins in these diabetic dogs resembled chylomicrons in their electrophoretic mobility, size, density, and composition. Surgical, histological and tracer studies suggested that in addition to the liver, the intestinal mucosa makes these lipoproteins. The tracer studies also suggested that circulating FFA might enter the intestinal mucosal cells directly and be esterified.

Adipose Tissue↗
PubMed1975

In vitro labeling of beta-apolipoprotein with 3H or 14C and preliminary application to turnover studies.

3-H- or 14-C-labeled methyl groups were introduced into apolipoproteins of human and pig low density lipoproteins (LDL). 98% of the label was recovered in the apoprotein of radiomethylated LDL. Such methylated lipoprotein was compared with the corresponding unlabeled LDL with respect to its electrophoretic and immunochemical properties, and its behavior in the analytical ultracentrifuge. The data demonstrated that neither the human nor pig LDL underwent gross changes as a result of methylation. The applicability of radiomethylated pig LDL as a tracer for studying the turnover of LDL in pigs was examined. The results showed that the behavior of unscreened and screened 3-H-labeled LDL was similar. The LDL disappeared with an initial t1/2 of 1.1 hr and a later t1/2 of 30 hr. These values agreed well with those reported for radioiodinated LDL. The technique of radiomethylation of lipoprotein may afford an advantage over radioiodination as it may label peptides that do not have tyrosine.

Animals↗
PubMed1975

Triglyceride turnover: a comparison of simultaneous determinations using the radioglyceride and the lipolytic rate procedures.

Two different methods of examining triglyceride turnover are described. One measures the clearance of endogenously labeled triglyceride glycerol, the radioglyceride method. The other assesses the hydrolysis of endogenous very low density lipoproteins after a primed infusion of maximal doses of heparin, the lipolytic rate. Both depend on widely different assumptions. A comparison of data obtained by both methods at the same time in single individuals with widely differing triglyceride concentrations revealed them to agree quite closely. This correspondence indirectly suggests the validity of the procedures. The procedures have been applied to show that fat-free high-carbohydrate diets accelerate triglyceride production in some humans.

Animals↗
PubMed1974

[Pharmacologic-endocrinological findings in animal experiments with TURISYNCHRON and SUISYNCHRON. 4. Analysis of residuals in pig carcasses].

Twelve groups of German Edelschwein were given the recommended dosage of metallibure zinc complex (SUISYNCHRON) or 5 and 10 times this dosage. Residues were determined in liver, muscle and fat of pigs killed 3-5 hours or 1,2,4,7 or 10 days after the end of administration. In agreement with report in the literature, the highest content was found in liver, followed by meat, with hardly any residues in fat. Taking into account the accuracy of the method of determination, significant residues were present in the liver of pigs given ten times the normal dosage and killed after 3-5 hours of 1 and 2 days, but in muscle only in those killed after 3-5 hours; the content in fat did not differ significantly from that of the untreated controls.

Adipose Tissue↗
PubMed1974

[Pharmacologic-endocrinological findings in animal experiments with TURISYNCHRON and SUISYNCHRON. 3. Selected pharmacologic and immunologic findings].

Comparison of the action of TURISYNCHRON and its zinc complex SUISYNCHRON in mice, rats and dogs showed that neither compound interfered with the implantation process in rats. After oral administration, blood concentrations were lower with SUISYNCHRON than with TURISYNCHRON. The zinc complex was broken down in the acid medium of the stomach, and absorbed in the duodinum or in distal segments of the intestine. Metallibure did not affect on phagocytosis not the course of infections with Escherichia coli or Erysipelothrix insidosa. Both compounds had a thymolytic action, which did not mimic the effect of cofticosteriods.

Adrenal Cortex Hormones↗
PubMed1972

Diabetes mellitus: current concepts of the hormonal and metabolic defects.

In the last 50 years our conception of diabetes has changed considerably. It is no longer just a failure of the pancreas to release insulin. It may be a resistance to insulin, so that amounts which would ordinarily be normal are no longer adequate for the body. The relative deficiency of insulin may also represent the release of what would otherwise be normal amounts of insulin at the wrong time. Indeed diabetes may not only be insulin deficiency, but also glucagon excess. The consequences of this complex hormonal imbalance are not simply failure to metabolize glucose, but also excessive production of glucose and alteration of the body's capacity to handle the other nutrients - amino acids and fatty acids. Not only may these two hormones, insulin and glucagon, regulate the metabolism of more than glucose alone but they are, in turn, regulated by more than glucose. Furthermore, one consequence of inability to burn glucose along normal pathways may be that it is converted to substances such as sorbitol and glycoproteins and this conversion may give rise to many of the complications of diabetes.

Amino Acids↗