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Biomedical subjects

H Jansen

Publications and source records attributed to H Jansen.

At least 181 records · Page 10Linked to original sources
PubMed1981

Liver lipase-like activity in human and hamster adrenocortical tissue.

Human adrenocortical tissue was found to contain a lipase activity that could be measured in vitro in the presence of 0.6 M NaCl at pH 8.5. The lipase was largely (80%) inhibitable by an antibody raised against heparin-releasable liver lipase. The activity of the lipase per gram tissue wet weighty was threefold higher in hyperplastic than in normal adrenocortical tissue (165 microunits vs 50 microunits). No or very low lipase activity was found in adrenocortical tumors. When, employing the same assay system, lipase activity was measured in the adrenal gland of golden hamsters a very low activity, compared with rat adrenal gland,--was found (13 mU)g w.w. vs 225 mU/g w.w.). Since liver lipase may be involved in the uptake of cholesterol from serum high density lipoproteins by the liver, the presence of a similar lipase in adrenal glands suggests that this tissue can also take up cholesterol by a lipase-mediated mechanism in human and rat. In human adrenocortical carcinomas and in the normal hamster gland such a mechanism seems to be absent.

Adrenal Cortex↗
PubMed1981

[Diffuse skeletal hemangiomatosis with involvement of internal organs (author's transl)].

Generalized haemangiomatosis of the skeletal is a very rare disease without characteristic radiological symptoms. The authors, who observed one case, give a survey of the literature, radiologic symptoms, pathological changes, clinical and therapeutical problems as well as of the prognosis. Stress is layed on the fact, that there is a marked distinction between generalized haemangiomatosis and progressive osteolysis Gorham-Stout. Attempts are made to find reliable characteristics for differentiation of a variety of pathological conditions, which present similar radiological pattern. The presented case shows uncommon osteoblastic bone changes, symptoms, which are rarely observed in this condition. The prognosis depends on the involvement of parenchymal organs: The nature of the disease should be judged as semimalign in cases of simultaneous involvement of skeletal and inner organs due to the high mortality, even in a definite benign histology.

Adult↗
PubMed1980

Lipoprotein lipase activity of adult rat cardiocytes.

Cardiocytes were prepared by enzymatic dissociation of adult rat ventricular tissue, and comparative studies on lipoprotein lipase activity were conducted on fresh homogenates and acetone powders of these cells. Lipolytic activity in fresh homogenates was largely dependent on addition of serum activator to the assay, and the activity was sensitive to 1 M NaCl. Lipoprotein lipase activity was maximized in acetone powder preparations of cardiocytes. Approx. 10% of the total lipolytic activity was extractable from acetone powders of cells homogenized in the absence of serum, while approx. 50% was soluble from powders of cells homogenized with 10% serum. The non-extractable lipolytic activity was inhibited 80% with 1 M NaCl and about 47% with antibodies (IgG) to heart lipoprotein lipase. The buffer-extracted enzyme was completely sensitive to NaCl and was inhibited 80% by low concentrations of anti-lipoprotein lipase antibodies.

Animals↗
PubMed1980

Properties of binding of lipases to non-parenchymal rat liver cells.

The binding of a heparin-releasable acylglycerol hydrolase from rat liver (liver lipase) to non-parenchymal liver cells was studied in vitro. The binding of the partially purified liver lipase to the cells was found to be rapid. Within 1 min 80% of the maximal binding occurred at either 4 or 25 degrees C. The binding capacity of the cells was saturable, with a maximal binding of 46 mU lipase activity per mg cell protein. Albumin did not prevent the binding and neither did glucose, galactose or methyl-alpha-mannoside. Mg2+, but not Ca2+, promoted the binding of the lipase to the cells. The in vitro bound enzyme activity was releasable from the cells by heparin. Both the soluble and bound liver lipase could be completely inhibited by an antibody against liver lipase. Lipoprotein lipase, derived from rat adipose tissue, was also found to bind preferentially to non-parenchymal liver cells. The presented results show that non-parenchymal liver cells contain 10(5) binding sites per cell for heparin-releasable lipases. Lipase secreted from parenchymal cells in vitro was also bound to the non-parenchymal cells. The data suggest that in vivo the liver lipase bound to endothelial liver cells can be derived from parenchymal cells.

Animals↗
PubMed1980

Activity of heparin-releasable liver lipase. Dependence on the degree of saturation of the fatty acids in the acylglycerol substrates.

The heparin-releasable liver lipase of the rat has a modest phospholipase A1 activity when dipalmitoylphosphatidylcholine is used as the substrate. The activity is more than doubled when dioleoyl phosphatidylcholine or soybean phosphatidylcholine (mainly containing esterified linoleic acid) are used instead. The hydrolase and transacylase activities of the enzyme with monoacylglycerol as the substrate also increase when unsaturated acylglycerols are used instead of saturated monoacylglycerols. The ratio of the rates of hydrolysis to transacylation increases when more saturated monoacylglycerols are used or when the availability of unsaturated monoacylglycerols (by the addition of albumin) to the enzyme is diminished. Therefore, in vivo the enzyme may be expected to have mainly hydrolytic activities, acting upon phospholipids and monoacylglycerols of lipoprotein particles and on monoacylglycerols bound to albumin. The higher activity on unsaturated fatty acid derivatives may contribute to the hypolipidemic effect of dietary (poly)unsaturated fatty acids.

Acyltransferases↗
PubMed1979

Influence of somatostatin on carbohydrate absorption in human small intestine.

Oral carbohydrate tolerance tests with xylose, galactose and lactose were performed. After an interval of at least 24 h the same tests were repeated following an i.v. bolus and during infusion of somatostatin. Somatostatin does not influence xylose absorption. However, absorption of galactose and lactose is significantly reduced (p less than 0.01/0.008) during somatostatin infusion. On the other hand, serum levels of galactose remain unchanged despite administration of somatostatin, when galactose is given parenterally. The results support the assumption that the absorption process in small intestine is affected by somatostatin. Possible effects of somatostatin on hormones regulating the intestinal absorption and on energy-depending carrier mechanisms are discussed.

Adult↗
PubMed1979

Alteration of the lipase activities of muscle, adipose tissue and liver by rapeseed oil feeding of rats.

Feeding rapeseed oil, rich in erucic acid, for 4 days results in a significant increase of the lipoprotein lipase activities of heart and adipose tissue. The lipase activity of liver, which in earlier studies has been shown to be releasable by heparin perfusion, also increases by the dietary regimen. The increased lipoprotein lipase activity of heart may contribute to lipid accumulation in this organ. The higher intracellular lipid store probably results in higher (hormone-sensitive) tissue lipase activity. The increase of lipoprotein lipase of adipose tissue, however, is not accompanied by an increase of hormone-stimulated tissue lipase activity in fat cells. This activity may even become lower, and might contribute to the decrease of the lipid store in heart after an initial rapid phase of fat accumulation during erucic acid feeding.

Adipose Tissue↗
PubMed1979

Nocturnal gastric drip feeding in glucose-6-phosphatase deficient children.

UNLABELLED: Six patients with glucose-6-phosphatase deficiency were treated for 12 hr at night with gastric drip feeding (GDF), containing soy milk plus glucose, dextrimaltose, and starch. An alarm system (thermistor), connected to the gastric tube, was devised in case of displacement of the tube by the child. The effects of GDF were as follows. Base deficit and lacticaciduria decreased, but did not normalize. Serum cholesterol levels tended to normalize, but serum triglycerides remained elevated. The hepatic and extrahepatic components of plasma lipoprotein lipase were measured separately 5 and 40 min after iv heparin injection. Hepatic triglyceride lipase activities which were subnormal to normal increased to the lower normal range. Extrahepatic lipoprotein lipase activities, though increasing after GDF, remained abnormally low. Catch-up growth occurred in all four growth-retarded children. The pronounced liver enlargement of the five patients, not previously treated with GDF, decreased markedly. SPECULATION: Nocturnal GDF in glucose-6-phosphatase deficient children, suppresses the tendency for hypoglycemia and acidosis which are causes for stress, catabolism, and anorexia. By suppressing these factors, GDF promotes anabolism and caloric intake, thus accounting for the catch-up growth seen in the patients with growth retardation.

Child↗
PubMed1979

Systemic lupus erythematosus--a zoonosis?

The medical history was obtained and a physical examination carried out--in addition to an immunological investigation of the blood and skin--on 11 dogs in the ownership of patients with systemic lupus erythematosus (SLE). The results were compared with those obtained from a control group and it was found that they do not support the hypothesis that SLE is a zoonosis.

Animals↗
PubMed1978

Regulation of lipoprotein lipase immunological study of adipose tissue.

An antibody to purified rat heart lipoprotein lipase was used to determine the relative specific activities of adipose tissue lipoprotein lipase from fed and fasted rats. The antibody was immobilized by coupling it to a Sepharose gel. This antibody bound approx. 80% of the lipoprotein lipase activity of extracts of rat adipose tissue. When the extracts were separated by gel chromatography into two lipase activity fractions (lipoprotein lipase "a" and lipoprotein lipase "b") and these fractions incubated with the antibody, only 10% of the lipoprotein lipase "a" activity was bound by the highest antibody concentration employed, whereas 93% of the lipoprotein lipase "b" was bound by the same amount of antibody. Increasing amounts of antibody incubated with extracts of adipose tissue of fed or fasted rats yielded similar titration curves. When a constant amount of antibody was incubated with increasing amounts of the adipose extracts, no significant difference was noted between extracts from fed and fasted animals. The data indicate that the high lipoprotein lipase activity of adipose tissue of fed rats, compared with that of rats fasted overnight, results from the presence of more lipoprotein lipase protein.

Adipose Tissue↗