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Biomedical subjects

N Katayama

Publications and source records attributed to N Katayama.

At least 325 records · Page 18Linked to original sources
PubMed1983

Steady-state kinetics of coupled two-enzyme reactor with recycling of poly(ethylene glycol)-bound NAD.

The kinetic properties of a continuous enzyme reactor containing rabbit muscle lactate dehydrogenase, horse liver alcohol dehydrogenase and poly(ethylene glycol)-bound NAD (PEG-NAD) were investigated experimentally and theoretically. The enzymes and PEG-NAD were retained in the reactor with an ultrafiltration membrane, and the substrates (pyruvate and ethanol) were fed continuously. The reactions of the dehydrogenases were coupled by the recycling of the cofactor. The steady-state concentration of L-lactate, one of the products, was measured under different experimental conditions and compared with the corresponding theoretical value. The theoretical value was calculated based on a simplified ordered bi-bi mechanism for the individual enzyme reactions, of which kinetic constants were determined by independent kinetic studies. Differences were found between the kinetic constants of the enzymes for NAD(H) and PEG-NAD(H). The steady-state values obtained by continuous operation were lower than those calculated, possibly due to the simplification made for the kinetic model; but there was general agreement between them in the dependence on the experimental conditions. The steady-state behavior of the enzyme reactor was explained semi-quantitatively by the simple kinetic model.

Alcohol Dehydrogenase↗
PubMed1983

A new instrument for percutaneous muscle biopsies.

A new instrument for percutaneous muscle biopsies is presented. It was tested in biopsies of the vastus lateralis, gastrocnemius, and brachioradialis muscles. With this instrument, percutaneous muscle biopsies were performed noninvasively and simply with procurement of sufficient material (30-40 mg) for satisfactory histological examination.

Biopsy↗
PubMed1983

[Clinical experience with cefoxitin in infections associated with hematopoietic disorders].

Ten inpatients at the Second Department of Internal Medicine, Mie University Hospital, developed infections in the course of treatment for hematopoietic disorders and were administered cefoxitin (CFX). Patients suffered from the following infections: pharyngitis, 2; bronchitis, 2; pneumonia, 2; sepsis, 2; bacteremia, 1; suspected cases of bacteremia, 2; and fever of unknown origin, 1. The number of infections totaled 12 as 1 patient with pharyngitis also developed sepsis and 1 patient with pneumonia developed bacteremia. Duration for the administration of CFX ranged between 5 and 18 days with a total dosage of between 30 and 108 g. Of the 10 patients treated with CFX, 9 were treated concomitantly with micronomicin (MCR), doxycycline (DOXY), or sulbenicillin (SBPC), some were treated concomitantly with only 1 of the drugs and some were treated concomitantly with 2 of the drugs. The following clinical results were obtained: Following treatment, 4 patients were considered "excellent", 5, "good", and 3, "poor". Clinical efficacy rate was 75%. Four strains of Gram-positive cocci (1 strain of S. aureus, 2 strains of S. epidermidis and 1 strain of Streptococcus sp.) and 3 strains of Gram-negative rods (2 strains of P. aeruginosa and 1 strain of E. cloacae) were found in the clinical specimens of the 10 patients. These results differed somewhat from reported data that Gram-negative rods such as E. coli, Klebsiella sp., Pseudomonas sp., Serratia sp., are dominant. No serious side effects requiring cessation of treatment were observed. Elevations in the levels of S-GOT, S-GPT, serum alkaline phosphatase, blood urea nitrogen, etc. were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1981

Thrombopoiesis- and megakaryocyte colony-stimulating factors in the urine of patients with idiopathic thrombocytopenic purpura.

The urinary extract from patients with severe, chronic idiopathic thrombocytopenic purpura (ITP) was capable of inducing significant thrombocytosis in rats in vivo and enhancing megakaryocyte colony formation in culture of mouse bone marrow cells. The apparent specific activity of megakaryocyte colony stimulating factor (MEG--CSF) in the ITP extract was approximately one-half of that of the urinary extract from patients with aplastic anaemia (AA). Daily injections of ITP extract did not cause an increase in Hb concentration, while rats receiving AA urinary extract revealed profound erythropoiesis 3 weeks later. In vitro assay of erythropoietin (EPO) failed to show significant EPO activity in the extract from patients with ITP. These findings excluded the possibility that the observed activities of thrombopoiesis-stimulating factor (TSF) and MEG--CSF in the ITP urinary extract are due to contaminating EPO. Urine of patients with severe ITP appears to be a good source of TSF and MEG--CSF.

Anemia, Aplastic↗
PubMed1980

Thrombopoiesis and megakaryocyte colony stimulating factor in the urine of patients with aplastic anaemia.

The urinary extracts from patients with aplastic anaemia and from healthy donors were investigated in vivo and in vitro for their ability to stimulate megakaryopoiesis and platelet production. There was a significantly higher concentration of thrombopoiesis stimulating factor (TSF) and megakaryocyte colony stimulating factor (MEG-CSF) in the urine from patients with aplastic anaemia than in that from healthy donors. Neuraminidase treatment did not affect the thrombopoietic activity of TSF, whereas coexisting erythropoietin (EPO) in the extract lost in its activity in vivo. These findings suggest that TSF and/or MEG-CSF seems to be different from EPO and that the urine from aplastic anaemia patients would be a good source of TSF and MEG-CSF for purification and characterization.

Anemia, Aplastic↗
PubMed1978

Binding of platinum to human transferrin.

A complex of platinum and human transferrin has been formed by appropriately combining apotransferrin (metal free protein) and potassiumchloroplatinate (K2PtCl4). Atomic absorption spectroscopy indicated that both primary bind sites on the protein participated in the complex. Electron paramagnetic resonance (EPR) examination showed that the bound platinum was not paramagnetic, and thus it is highly probable that the Pt ion is in the +2 oxidation state. The results suggest a possible mechanism for physiological distribution of third-transition-series metals.

Chemical Phenomena↗
PubMed1978

Changes in T cell population in patients with bronchogenic carcinoma.

Absolute numbers of T cells were measured in a series of 84 patients with bronchogenic carcinoma and were compared with T cell percent with regard to clinical stage, course, and histologic type. Although T cell percent declined in accordance with the advancement of stage, the differences between the stages were not statistically significant. On the other hand, the absolute number of T cells decreased prominently in Stages III and IV as compared to Stages I and II (p less than 0.05 between Stages I and III, P less than 0.001 between Stages I and IV, and p less than 0.05 between Stages II and IV). Likewise in patients who were followed serially after resection, the absolute number of T cels correlated well with the postoperative course. These results lead us to the conclusion that it is more useful estimate the absolute T cell count rather than T cell percentage in lung cancer.

Carcinoma↗