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Biomedical subjects

F A Hommes

Publications and source records attributed to F A Hommes.

At least 91 records · Page 5Linked to original sources
PubMed1976

The development of creatine kinase in rat skeletal muscle. Changes in isoenzyme ratio, protein, RNA and DNA during development.

The activity of cytosolic creatine kinase in rat skeletal muscle rises stepwise during development. The increases occur simultnaeously with transient increases in DNA content. The second increase is accompanied by a rise in total protein, soluble sarcoplasmic protein and RNA/DNA ratio. Such changes are not observed at 20 days after birth, when creatine kinase finally accumulates to the adult level. Transient higher amounts of the MB and BB isoenzymes are observed after the first and second stepwise increase. The increase in creatine kinase activity observed after birth is predominantly due to an activation of the M gene. The BB isoenzyme is still present in adult skeletal muscle, but contributes little to the total activity.

Age Factors↗
PubMed1975

The effect of vitamin E deficiency on permeability of mitochondria for phosphate.

We have investigated whether the earlier-found decreased unsaturation in mitochondrial membranes in vitamin E deficiency affects the permeability properties of mitochondria. The iso-osmotic swelling technique was used as a measure for the rate of uptake of substrates by these organelles. A significantly slower uptake could be observed of ammonium malate in the presence of phosphate and of ammonium phosphate. These changes in membrane permeability might give a clue to the mechanism of some metabolic abnormalities as seen in vitamin E deficiency in relating these abnormalities to specific membrane functions, e.g. an affection of carriers; for instance the phosphate carrier.

Ammonium Chloride↗
PubMed1975

Fatty acid composition of some cellular membranes of fetal rat liver.

The fatty acid composition of lipids of inner mitochondrial membrane, rough and smooth endoplasmic reticulum of adult and fetal rat liver has been determined. Subcellular membranes of fetal liver show a higher content of palmitic acid and oleic acid and a lower content of stearic acid and arachidonic acid as compared to subcellular membranes of the adult liver. The activity of citrate lyase and acetyl-CoA carboxylase of rat liver cytosol has been determined as a function of age. It is concluded that the differences are due to a relative deficiency of the fatty acid elongation system. The higher degree of saturation of the fatty acids of the phospholipids of the fetal membranes may be the cause of altered permeability properties of these membranes, as illustrated by the slower rate of isoosmotic swelling in the presence of the ammonium salt of some of the Krebs cycle intermediates in fetal rat liver mitochondria.

ATP Citrate (pro-S)-Lyase↗
PubMed1975

Studies on the valine sensitivity in non-ketotic hyperglycinemia.

An oral loading test with L-valine (100 mg/kg body weight) in 3 patients with non-ketotic hyperglycinemia was accompanied by drowsiness and hyperreflexia of the patients. Metabolic studies revealed a slightly lower rate of disappearance of valine from blood in 2 of the patients. In a third patient, the curve was not different from controls. Gas chromatographic analysis for short-chain fatty acids in serum carried out during the valine loading test did not show increased concentrations. Urine collected during the valine loading test did not show excretion of N-acylglycine derivatives. As neither of the branched chain amino acid transaminases proved to be inhibited by glycine, inhibition by glycine of the uptake of valine by the tissues became likely. This uptake has been measured in rat liver slices. Glycine was found to be a competitive inhibitor of valine uptake, with a Ki of 4.9 mM. It is concluded that the tendency to a decreased rate of valine disappearance from blood in non-ketotic hyperglycinemia could be due to an inhibition of valine uptake by the high plasma glycine concentration. The relationship of the inhibited valine uptake in liver slices of rats with the clinical symptoms in non-ketotic hyperglycinemia patients after a valine load remains to be established.

Animals↗