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Biomedical subjects

D Onicescu

Publications and source records attributed to D Onicescu.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Cytochemical demonstration of folic acid in normal and leukemic granulocytes.

By means of an original cytochemical method, folic acid was demonstrated "in situ" in peripheral white blood cells in acute and chronic granulocytic leukemia. In control blood smears folic acid-relevant granules were found predominantly in the nuclei of neutrophils and basophils. Eosinophils were found positive for folic acid reaction both in nuclei and cytoplasm. In leukemic undifferentiated cells, less marked in acute than in chronic granulocytic leukemia, the cytoplasms contained a great quantity of folate. Nuclei were fewer or nonreactive. Therefore the cytochemical localization may be related to the degree of the white cells differentiation.

Folic Acid↗
PubMedDate not supplied

Histochemical study of leucine aminopeptidase in leukemia.

By means of a histochemical method, the leucine aminopeptidase activity was studied in human normal and leukemic peripheral blood. Before administration of cytostatics the enzymic activity was high in the cytoplasm of blasts and in the nuclei of segmented cells. After therapy the activity of leucine aminopeptidase in blasts decreased, while in polymorphs it became negative in nuclei and positive in their cytoplasm. The non-granular leukocytes and platelets displayed a weak enzymic activity both in normal and malignant blood cells. The erythrocytes were negative.

Antineoplastic Agents↗
PubMedDate not supplied

Ultrastructural localization of Ca2+ in the Golgi apparatus of two different cell types.

The precipitation reaction with potassium oxalate was used to investigate the subcellular localization of Ca2+ in atrial myocardocytes and in Schwann cells of non-myelinated nerve fibers. Chelation with EGTA was used to prove the presence of Ca2+ in the electronoopaque deposits. In both cell types the oxalate reaction was intense in the classically described Ca2+ deposits: the perinuclear cisterna, the endo (sarco) plasmic reticulum, the mitochondrial matrix, but also in a novel localization: the cisternae of the Golgi stack in all cis to trans positions, suggesting that Golgi Apparatus is a major intracellular Ca2+ pool.

Animals↗
PubMedDate not supplied

Cholinergic innervation of the ventricular myocardium in the human fetal heart.

Specimens of human fetal hearts from the 9th to the 27th week of intrauterine life were processed by the technique of Karnowski and Roots as modified by Lewis for the demonstration of acetylcholinesterase-positive nerve fibers by light microscopy. Cholinergic innervation was present in both atria and ventricles even in the 9th week of intrauterine life. In the ventricles the number of cholinergic fibers augmented with increasing age; they spread in the ventricular wall surrounding the vascular network including capillaries, or following their course in the close proximity of cardiac muscle fibers. Electron microscopy of heart specimens in the 27th week of intrauterine life showed that ventricular cholinergic nerve terminals were present in the subendothelial space of arteries; other cholinergic fibers were in a close apposition with ventricular myocardial cells with an intervening space of about 300 nm. These data provided evidence that the development of cholinergic innervation in both atria and ventricles of human heart began early during the intrauterine life.

Cholinergic Fibers↗
PubMedDate not supplied

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. Stereological studies showed in electron micrographs great differences from one cell type to another for the volume of mitochondria: 8% in acinar cell, 4.8% in centroacinar cell, 15.3% in small ductal cell and 4% in endocrine cell. The results strongly support the idea that centroacinar and intercalated ductal cells constitute the segments of pancreatic excretory cells, where the alkalinization of pancreatic juice takes place mainly by the secretion of bicarbonate and resorption of chloride ions.

Animals↗
PubMedDate not supplied

Histochemical localization of folic acid in the motor end plate.

Folic acid investigated in motor end plate by histochemical method appeared in the long nerve terminals of the motor axon, in the cytoplasm of Schwann cell. In muscle fibre opposite to the nerve arborizations, spaced granular lines perpendicular to the sarcolemma were observed.

Animals↗
PubMedDate not supplied

[Visual pigments].

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Color Vision Defects↗