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Biomedical subjects

H Holm

Publications and source records attributed to H Holm.

51 records · Page 3Linked to original sources
PubMed1979

Inhibition of human and rat pancreatic proteinases by crude and purified soybean proteinase inhibitors.

Effects of proteinase inhibitors on total proteolytic activity and trypsin and chymotrypsin activity in human pancreatic juice were determined separately. Purified inhibitors as well as crude extracts of raw soybeans completely inhibited trypsin and chymotrypsin activity while 40 to 50% of the total proteolytic activity remained. Inhibition experiments with 1,10-o-phenanthroline showed that this residual proteolytic activity was due mainly to carboxypeptidase A and B. Comparative studies with rat pancreatic enzymes demonstrated certain similarities between the corresponding enzymes from rat and man. However, differences were revealed which indicate that the rat enzymes must be used with great caution when applied as models for the human proteinases when studying effects of soybean inhibitors.

Animals↗
PubMed1978

Protein depletion and energy retention in rats with ventromedial hypothalamic lesions.

The catabolic effect of bilateral lesions in the ventromedial are of the hypothalamus (VMH) was studied in nitrogen-balance experiments and compared with the effect of a sham-operation in control animals. A transitory (24 h) increase in urine nitrogen was found in the controls, while in the lesioned animals, a persistent increase was found as long as the animals were fed. Fasting (48 h) eliminated the difference in urea excretion between the groups. Food-dependent effects of the VMH lesion are suggested. The changes in body and organ composition of VMH-lesioned animals, kept for 4 months on a food intake close to normal, were studied. The massive increase of body lipids and marked decrease of body protein and water was primarily due to increased subcutaneous-and abdominal-fat, and reduced skeletal and skin protein. An almost normal composition of the liver and close to normal amounts of protein in the viscera demonstrate that at least some tissues in VMH animals are able to maintain a normal protein content. Hyperphagia as a means to counteract the increased amino acid catabolism and to sustain the lean body mass is discussed.

Amino Acids↗
PubMed1975

Protein metabolism in rats with ventromedial hypothalamic lesions: dietary effects on nitrogen retention.

The protein metabolism of rats bearing bilateral lesions in the ventromedial area of hypothalamus (VMH) was studied in nitrogen balance experiments employing high protein and high fat diets. The catabolic effect of VMH destruction was to a great extent counterbalanced by increased protein intake. This indicates that increased amino acid catabolism, rather than impaired mechanisms for protein synthesis, is responsible for the poor nitrogen retention of VMH-lesioned rat fed normal amounts of protein. A trend of increasing nitrogen excretion with increasing dietary fat was found when the caloric intake of VMH-lesioned animals was elevated by substitution of dietary carbohydrates with fat. Persistent liponeogenesis in spite of the high fat intake, is suggested as a possible explanation for this observation.

Animals↗
PubMedDate not supplied

Perfusion in vivo of the porcine placenta. Fixation for EM.

A method for vascular perfusion in vivo, especially for EM fixation, was developed with the porcine placenta. The effect of fixation at varying parameters was studied. Nine multiparous Danish Landrace sows ranging in gestation from 33 to 112 days and in body weight from 160 to 257 kg were used. After general and local anaesthesia laparotomy was undertaken on the left flank and the uterine horn was perfused through a. uterina with buffered glutaraldehyde. Local perfusion through a. umbilicalis was undertaken in one case, and installation of concentrated glutaraldehyde into the allantoic cavity was performed in five cases. Perfusion-fixed and fresh tissue samples were fixed in OsO4 and processed for electron microscopy. The osmolarity of the buffer was varied between 470 and 660 mOsm. At high tonicity cytoplasm was well preserved but the intercellular spaces of the uterine epithelium was dilated. At about 575 mOsm the preservation was still good and the spaces were occluded. At lower tonicity damage occurred in the cytoplasm. The trophoblast was generally better preserved than the uterine epithelium. A rapid perfusion flow was beneficial for fixation.

Animals↗