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Biomedical subjects

D Onicescu

Publications and source records attributed to D Onicescu.

At least 19 recordsLinked to original sources
PubMed1979

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. Thus the enzyme --- substrate ratio appeared to favour the enzyme in young animals but the substrate in old animals.

Aging↗
PubMed1979

The kinetics of the histochemical method for dihydrofolate dehydrogenase (dihydrofolate reductase).

The purpose of the present investigation is to report some histochemical and cytospectrophotometric observations providng more objective evidence for the specific activity of the histochemical method for dihydrofolate reductase activity (5.6.7.8-tetrahydrofolate: E.C. 1.5.1.3). Kinetic factors of the enzymic reaction, such as fixation, pH, coenzymes, substrate concentration, Michaelis constant, temperature, time of incubation, aerobiosis, and anaerobiosis, activators and inhibitors, were investigated.

Animals↗
PubMed1979

"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.

Aging↗
PubMed1975

The in situ localization of folic acid.

A histochemical azo-coupling method for localizing folic acid in situ is described. Cat and rat liver, kidney, bone marrow and brain were found to be rich in folic acid; stomach, intestine, salivary glands, and blood contained less. Folic acid was localized in the cytoplasm of tissues having a very active metabolism, but in the nucleus of highly specialized cells such as neurons.

Animals↗
PubMed1975

Cholinergic innervation of the human stomach.

A histochemical method for the acetylcholinesterase activity was used to establish the parasympathetic components of the gastric coats in man. The four gastric layers contain a rich cholinergic innervation. In the mucosa the positive nerve fibers are located around the gastric glands and between the muscles of the muscularis mucosae. In the submucosa rich interconnected nerve fibers, rare large nerve trunks, and scarce ganglia cells show a strong cholinergic reaction. The muscular layer contains the highest density of cholinergic nerve fibers, isolated or in large bundles. Auerbach's plexus has a strong acetylcholinesterase activity in the nerve cell bodies. The subserous layer is very rich in cholinergic nerve fibers, rarely isolated, but interconnected. The vessels of each gastric layer exhibit a rich cholinergic innervation in the adventitia and the outside part of media.

Acetylcholinesterase↗
PubMed1975

On the histoenzymology of the human stomach.

By means of histochemical methods, the stomach in the man was studied for some oxidoreducing enzymes and hydrolases. The surface epithelium displays in the fundic area a mean activity which grows intense in the pyloric area. The parietal cells show a very high mitochondrial dehydrogenase activity, while the chief ones display a moderate oxidative activity. The pyloric glands exhibit a positive reaction for oxidoreducing enzymes with great differences of intensity from one cell to another. Around each principal and pyloric gland one can see an intense ATP-ase reaction in the endothelium of vessels and a very intense acid phosphate activity in the histiocytes. The submucosa, muscularis externa and serosa are very active for oxidoreduction and ATP-ase.

Adenosine Triphosphatases↗
PubMed1975

Cytoenzymologic activities of some oxidroeductases and alkaline phosphatase of leucocytes in Basedow, Cushing and Addison diseases.

Leukocytes, approached by histoenzymological methods for demonstration of dihydrofolate dehydrogenase, NADH2-diaphorase, lactate dehydrogenase and alcaline phosphatase activities, provided information about the impaired metabolic balance of thyrotoxicosis, Cushing and Addison diseases. The most relevant variations were found in thyrotoxicosis, the most sensitive enzyme was dihydrofolate dehydrogenase and the less sensitive was alcaline phosphatase. The neutrophils and lymphocytes had more evident enzymic variations.

Addison Disease↗
PubMed1975

Folate metabolism in normal peripheral leukocytes in children.

The activity of dihydrofolate dehydrogenase by histochemical method in children leukocytes was investigated. Blood leukocytes have a positive enzymic activity. Except monocytes a large enzymic variability was observed in neutrophils, eosinophils, and lymphocytes in puberty and at the onset of the adolescence. Enzymic activity varies with blood cellular type, the age, in males and females and from one child to another.

Adolescent↗
PubMedDate not supplied

Histoenzymatic activity of leucine aminopeptidase in normal bone marrow cells.

Human, monkey, cat and rat bone marrow cells were studied for the histochemical localization of leucine aminopeptidase activity. The granulocytes have a weak enzymic activity in the immature cells and a very strong one in the differentiated cells. The lymphopoiesis is characterized by a strong reaction in the lymphoblasts and different degrees of the enzyme activity in the lymphocytes. In the erythropoiesis, the undifferentiated cells are strongly positive, while the erythrocytes are negative. The immature and mature cells of the megakariocytic line show a weak leucine aminopeptidase activity.

Age Factors↗
PubMedDate not supplied

Histoenzymological study on desquamative cervico-vaginal cells.

Dihydrofolate dehydrogenase activity was histochemically investigated comparatively to the activities of 6-phosphogluconate, glucose-6-phosphate, malate and lactate dehydrogenases, NADH-2-tetrazolium dehydrogenase, esterases, beta-glucuronidase and leucyl aminopeptidase in smears of desquamative cervico-vaginal cells of negative and positive Papanicolaou classes. Dihydrofolate dehydrogenase was found active in a greater percentage of cells and stronger in individual cells of cervical carcinoma than in normal, inflammatory or dysplastic cervix uteri. The other enzymes activities were less specifically increased in dyskaryotic cells.

Carcinoma, Squamous Cell↗
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↗