Calcium cytochemistry and stereological morphometry of the intercalated ductal cells of the pancreas.

Using K-antimonate procedure, Ca2 binding sites in pancreatic small ductal cells were studied. Great precipitates were observed in the lumen of intercalated ducts, on luminal, contraluminal and lateral plasmalemma of centroacinar cells and in some of their organelles especially in mitochondrial matrix as well as on the euchromatin. Fine precipitates were present mainly on the endomembranes of perinuclear cisternae, endoplasmic reticulum, Golgi vesicles, mitochondria, secretory vesicles.

On the unity of cytomembrane system in the skeletal muscle.

In situ cytochemical evidence for specific Ca-binding sites in the cytomembrane system of skeletal muscle fibers is reported. High Ca accumulation was found at the junctions between different types of cytomembranes. Such junctions might represent "gate-locks" for intracellular Ca movements.

Folate metabolism in the superior cervical ganglion histochemical study.

By means of histochemical methods, folic acid, dihydrofolate reductase and NADH2-cytochrome-C-reductase were studied in the bovine superior cervical ganglion, in parallel with quantitative estimations of dihydrofolate reductase activity and in connection with the process of ageing. Various levels of folate metabolism were present in nerve cells and glial cells, as well as in pre or postganglionic nerves. In the process of ageing the activity of dihydrofolate reductase gradually decreased and the folic acid concentration in the nerve cells increased.

"In situ" variation of folic acid and dihydrofolate reductase in the caudate nucleus in the ageing process.

In bovine caudate nucleus of young animal, a folic acid-positive reaction was found in the perikarya and in the neuroglia in parallel with a high dihydrofolate reductase activity in the nerve cells. In old animals, folic acid increased in neurons, neuroglia and some nerve cell processes; the folate enzyme was markedly decreased in neurons and increased neuroglia NADH2-cytochrom-C-reductase activity was strongly positive in nerve cells in young and old animals.

Histochemical study on the dihydrofolatereductase and folic acid in mammalian brain cortex.

Histochemical and biochemical studies on the folate metabolism (folic acid an its principal enzyme-dihydrofolate-reductase) in bovine cortex - gyrus marginallis in the process of ageing were performed, in parallel with NADH2-cytocrom-C-reductase (diaphorase). Folic acid and folate enzyme, weak positive in neurons in young age, increased in old age in nerve cells and especially in their processes and in capillaries. The diaphorase strongly increased in all cells, glia and vessels, in old age.

The effect of etafenone on the subcellular distribution of calcium and some oligoelements in heart muscle. Ultracytochemical and x-ray microanalytical study.

In order to detect the subcellular localization of calcium in the myocardium of laboratory animals (rats and guinea-pigs) under the influence of 2'-(2-diethylaminoethoxy)-3-phenyl-propiophenone (etafenone, Baxacor) (4 mg, 20 mg and 100 mg/kg body weight) two ultracytochemical methods, with lead acetate and with potassium pyroantimonate, were used. In addition, X-ray microanalysis of myocardial fragments was performed. The correlation of ultrastructural, ultracytochemical and X-ray microanalytical findings provides direct evidence of the hypothesis that etafenone acts on myocardium as a so-called "calcium antagonist".

Calcium in smooth muscle sarcoplasmic reticulum in situ. Conventional and X-ray analytical electron microscopy.

Numerous electron-opaque deposits appear in the SR of the relaxed smooth muscle cells of the guinea pig Taenia coli that had been treated, before fixation, with a depolarizing medium containing oxalate to precipitate calcium ions in situ. X-ray spectra obtained by spot and line-scanning analyses of these deposits in situ show characteristic calcium signals, thus providing direct evidence for calcium accumulation inside the sarcoplasmic reticulum of smooth muscle.