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Biomedical subjects

H Hara

Publications and source records attributed to H Hara.

At least 19 recordsLinked to original sources
PubMed1979

Measurement of the protein-synthetic activity in vivo of various tissues in rats by using [3H]Puromycin.

The validity of a new technique was examined for estimating the protein-synthetic activity of various tissues in vivo. The basic assumption underlying the method is that the number of peptide chains growing on each active ribosome would increase as the protein-synthetic activity of each tissue increases. The principle of the procedure, which was devised originally by Wool & Kurihara [(1967) Proc. Natl. Acad. Sci. U.S.A. 58, 2401-2407] to determine in vitro the number of functional ribosomes in skeletal muscle, is as follows. Puromycin is known to bind easily to the C-terminal end of the growing peptide on ribosomes and thus stop further chain elongation. Hence, if the number of puromycin molecules attached to the nascent peptide is determined by using radioactive puromycin as a tracer, one can estimate the number of growing peptides, i.e. the activity of tissue protein synthesis. By using this technique, it is shown that both starvation and the feeding of a protein-free diet caused marked decreases in the relative rate of formation of peptidyl-puromycin, i.e. activity of protein synthesis in liver, skeletal muscle, heart, spleen, testis, lung, kidney and intestine.

Animals↗
PubMed1979

Insulin dependent and independent actions of dietary protein on in vitro protein synthesis in skeletal muscle of rats.

Insulin dependency of the effect of dietary protein on in vitro protein synthesis in skeletal muscle was studied in rats. Re-feeding fasted rats with an adequate protein diet caused an increase in protein synthetic activity of skeletal muscle within only 5 hours with a concomitant increase in concentration of polyribosomes. During re-feeding of a protein-free diet muscle protein synthesis increased significantly but it was somewhat lower than in rats fed an adequate protein diet. The concentration of insulin in plasma increased promptly and markedly when the rats were re-fed either of these diets. However, the degree of increase was slightly less in rats fed a protein-containing meal. Re-feeding normal rats with egg albumin alone, after fasting 1 day, produced a marked increase in protein synthetic activity of skeletal muscle with a parallel increase in proportion of polyribosomes in the tissue. The stimulatory action of dietary protein on muscle protein synthesis was not abolished even in streptozotocin-diabetic rats. However, there was no appreciable change in ribosomal profile in the diabetic rats. These results indicate that the function of dietary protein in regulating muscle protein synthesis is not mediated entirely by insulin.

Animals↗
PubMed1979

Therapy and prognosis of status convulsivus in childhood.

The record of 67 cases under 15 years of age who were hospitalized during status convulsivus from 1975 to 1978, the 348 cases who visited the hospital for the first time with epilepsy (Oct. 1977 to Sept. 1978) and the 32 cases who were hospitalized during status epilepticus from 1969 to 1974 and who are being followed up as outpatients were studied. The frequency of status epilepticus was 8% among epileptic children. There was no difference in the frequency of incidence between male and female. Patients with mental retardation, however, were revealed to have status epilepticus twice to three times more frequently as compared to cases without mental retardation. The major seizure types of status epilepticus in childhood were generalized tonic clonic convulsion and unilateral clonic convulsion. In 25% of the cases, status epilepticus was the first ictal manifestation. The major cause of status convulsivus was epilepsy, followed by encephalitis and encephalopathy, but cases due to brain tumor were rare. The drug of first choice for status convulsivus is diazepam. If there is any difficulty in controlling status convulsivus with diazepam, it may be worthwhile to consider what the problem is, causes of status convulsivus, seizure type, or basic disease of the patient. The effective dose of diazepam was within the range of 0.3--0.5 mg/kg. When the effect is not sufficient, the dose of diazepam should be increased to 1 mg/kg while watching the general condition of the patient. Factors affecting the prognosis of status convulsivus were its cause, duration, onset age and effectiveness of therapy during the acute stage. The frequency of cases who suffered disability after status epilepticus was 56%. (transient disability 43%, permanent disability 13%) The most frequent type of transient disability was hemiplegia. Most epileptic children who had repetitive status convulsivus revealed psychomotor retardation before first status. Factors which cause repetitive status seem to be hemispheric brain damage or diffuse corticocentrencephalic damage.

Adolescent↗
PubMed1979

Extramedullary plasmacytoma of the gastrointestinal tract in a renal transplant recipient.

A case of gastrointestional plasmacytoma found in a renal transplant recipient is described. Immunohistochemical study using immunoglobulin-enzyme bridge technique demonstrated IgA and k-type light chains in the majority of plasma cells infiltrated in the stomach. Pathological investigation revealed multiple similar tumors in the ileum, cecum and ascending colon suggesting a plasmacytoma of multicentric gastrointestinal origin. The pathogenesis of plasma cell tumors is briefly discussed with regard to organ transplantation.

Adult↗
PubMed1978

Murine hemopoietic colonies in culture containing normoblasts, macrophages, and megakaryocytes.

Murine marrow cells, when incubated in methylcellulose culture in the presence of erythropoietin and conditioned medium for two weeks, produced large macroscopic bursts containing normoblasts, macrophages, and often megakaryocytes. The clonal nature of these mixed colonies was supported by linearity studies and analysis of the percentages of constituent cells in different plating conditions. Time course observations and studies of the effects of L-cell-conditioned medium revealed that colony-forming cells for the mixed colonies (CFU-mix) are at earlier stages of hemopoietic development than burst-forming units (BFU-E). The mean of the modal sedimentation velocities of CFU-mix was 3.4 mm/hr and was in close agreement with that reported for the spleen colony-forming units. Almost none of the CFU-mix was in a DNA synthetic phase as measured by short-term exposure to tritiated thymidine. These results strongly indicate that CFU-mix represent a population of pluripotent hemopoietic stem cells in murine marrow.

Animals↗
PubMed1978

Effect of chloramphenicol on colony formation from erythrocytic precursors.

In the present experiments, we compare the behavior of erythropoietic precursors and granulocytic precurosors exposed to chloramphenicol. Subcutaneous injection of 20 mg of chloramphenicol sodium succinate on five successive days induced a reduction in the number of erythrocytic colony-forming units (CFU-E) and erythropoietic burst-forming units (BFU-E) in murine marrow and spleen, while no change in number of granulocytic precursors (CFU-C) in murine hemopoietic organs was observed. In vitro studies demonstrated concentration-dependent inhibition of chloramphenicol or chloramphenicol sodium succinate in the colony formatin of all these precursors from murine and human bone marrow. However, erythropoietic burst formation of murine and human BFU-E was completely suppressed by the addition of chloramphenicol or chloramphenicol sodium succinate to the culture medium at therapeutic concentrations (20--40 microgram/ml). From the present results, it can be concluded that the reduced number of BFU-E in mice after injection of chloramphenicol sodium succinate resulted from the selective toxicity of chloramphenicol to BFU-E at therapeutic concentrations.

Animals↗
PubMed1978

Fluorescence and electron microscopic studies on the perivascular mesenchymal cells and fibroblasts after vitamin A administration.

Findings of perivascular mesenchymal cells and fibroblasts in mice receiving large doses of vitamin A were described. Liver, lung, intestine and skin were investigated by fluorescence and electron microscopy. Marked increase of fluorescence of vitamin A was observed in the sinusoidal wall of the liver, in the alveolar septa of the lungs, in the propria mucosa, submucosa and muscular layer of the intestine and in the dermis of the abdominal skin. Increased fluorescence of these organs corresponded, ultrastructually, to the appearance of numerous fat droplets in Ito cells of the liver, septal cells of the lung and fibroblasts of the intestine and of the skin. All of these cells showed the same morphological features and the same distribution in the tissue, namely in the interstitial connective tissue space. These findings indicate that vitamin A storing cells are distributed widely in the connective tissue of various organs and that perivascular vitamin A storing mesenchymal cells and interstitial fibroblasts are probably of common fibroblastic cell line.

Animals↗