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Biomedical subjects

T Okazaki

Publications and source records attributed to T Okazaki.

At least 379 records · Page 21Linked to original sources
PubMed1985

An alkaline thiol proteinase in the liver mitochondria of bullfrog, Rana catesbeiana.

The mitoplasts were prepared from bullfrog (Rana catesbeiana) liver mitochondria by treatment with digitonin and were then separated into the matrix and inner membrane fractions. The matrix fraction thus obtained was free of lysosomal contaminations and exhibited a distinct proteinase activity. pH dependency of the matrix proteinase activity measured in the presence and absence of iodoacetamide revealed that the matrix contained at least two kinds of proteinase, a major alkaline thiol proteinase having an optimal pH at 8.5 and a minor neutral proteinase having an optimal pH at 7.5. The major matrix proteinase activity was strongly inhibited by leupeptin, chymostatin, antipain and E64-C, an inhibitor of Ca2+-dependent thiol proteinase, while it was scarcely affected by diethylpyrocarbonate. The activity was also inhibited by DTNB and p-chloromercuribenzoate. Addition of hydrocarbon compounds such as ethylene glycol, glycerol, Triton X-100 and poly (ethylene glycol) to the reaction mixture was found to decrease the matrix proteinase activity. Neither cytochrome c nor glutamate dehydrogenase was hydrolyzed when subjected to the matrix proteinase activity in vitro. On the other hand, cytochrome c oxidase was effectively hydrolyzed, and the enzyme associated with the mitochondrial innermembrane fragments was partially hydrolyzed by the major matrix proteinase activity.

Animals↗
PubMed1985

Collagenase-like peptidase activity in serum from patients with rheumatoid arthritis.

The activities of collagenase-like peptidase, estimated by using (succinyl-Gly-Pro-Leu-Gly-Pro-Leu-Gly-Pro)-4-methylcoumaryl-7-amide as substrate, and of dipeptidyl-aminopeptidase IV were decreased in the sera from patients with rheumatoid arthritis. Both enzymes bring about the degradation of peptides derived from collagen. A significant positive correlation was observed between the activities of the two serum peptidases.

Arthritis, Rheumatoid↗
PubMed1985

Analysis of serum lactic dehydrogenase levels and its isoenzymes in ovarian dysgerminoma.

The usefulness of serum lactic dehydrogenase (LDH) levels and its isoenzyme analysis as potential malignant ovarian tumor markers was investigated in 74 patients, including 5 cases of ovarian dysgerminomas. In this study 41.7% of patients with ovarian adenocarcinomas of the common epithelial types and 29.4% of cases with metastatic ovarian carcinoma had elevated preoperative serum LDH levels. In contrast all 5 cases of ovarian dysgerminomas had extremely high levels of serum LDH prior to therapy, whereas all 11 cases of benign solid ovarian tumors had normal LDH levels. The analysis of LDH isoenzymes revealed that ovarian dysgerminomas had high levels of the two fast fractions of LDH, whereas other malignant ovarian tumors had elevated levels of the two slow fractions. The present findings indicate that serum LDH levels and electrophoresis of its isoenzymes may be of value in patients with ovarian dysgerminomas.

Adult↗
PubMed1985

Different effects of 4-(4'-chlorobenzyloxy)benzoic acid (MII) on lipid synthesis and cell growth in human and mouse skin fibroblasts.

The effect of 4-(4'-chlorobenzyloxy)benzoic acid (MII), a metabolite of a new hypolipidemic agent 4-(4'-chlorobenzyloxy)benzyl nicotinate (KCD-232), on lipid synthesis and cell growth was studied in human skin fibroblasts (HSF), mouse skin fibroblasts (MSF) and other rodent-derived cell. MII inhibited sterol synthesis in both HSF and MSF in a dose dependent manner. The drug also suppressed fatty acid synthesis, weakly in HSF and markedly in MSF. The growth of MSF was inhibited by MII in a dose dependent manner, whereas that of HSF was not inhibited at all by MII up to 1 mM. The MII-mediated inhibition of MSF growth was not prevented by the addition to the medium of intermediates of the cholesterol synthetic pathway, i.e., mevalonate, squalene or lanosterol. Furthermore, the growth of several cell lines derived from rodents (L, CHL and AH109A cells) was suppressed by MII. These results suggested a possibility that the different effects of MII on the growth of HSF and MSF might be due partly to differences in the effect of MII on fatty acid synthesis between human and rodent cells.

Acetates↗
PubMed1985

Griseolic acid, an inhibitor of cyclic adenosine 3',5'-monophosphate phosphodiesterase. I. Taxonomy, isolation and characterization.

Griseolic acid, a potent inhibitor of cyclic adenosine 3',5'-monophosphate (cyclic AMP) phosphodiesterase (EC 3.1.4.17) was isolated from the cultured broth of Streptomyces griseoaurantiacus SANK 63479. Griseolic acid has an adenine moiety and two carboxyl groups and possesses the molecular formula C14H13N5O8. Griseolic acid inhibited cyclic AMP phosphodiesterase competitively with regard to cyclic AMP, the substrate and the resulting Ki value was 0.26 microM. Griseolic acid showed the most potent inhibitory effect on rat aorta cyclic AMP phosphodiesterase among the enzymes of several rat organs tested. The plasma level of cyclic AMP was increased when griseolic acid was subcutaneously injected rats.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1985

Effect of antimetabolites and thymidine blockage on the induction of differentiation of HL-60 cells by retinoic acid or 1 alpha,25-dihydroxyvitamin D3.

Induction of differentiation of the HL-60 human promyelocytic leukemia cell line by retinoic acid or 1 alpha,25(OH)2D3 was analyzed under the condition in which cellular DNA synthesis was inhibited by several antimetabolites or blocked by thymidine. The results demonstrate that differentiation occurs in the absence of DNA synthesis and that some inhibitors of DNA synthesis may enhance the differentiation of HL-60 cells by the above inducers. Among the antimetabolites used, the enhancement of induction of differentiation by hydroxyurea was shown to be more effective than that of Ara-C or aphidicolin. The effect of thymidine blockage was similar to that of hydroxyurea. These different effects may be due to the different points at which the cell cycle is blocked by these agents. These results seem to be common in both the differentiation of the granulocytic line induced by retinoic acid and of the macrophage line induced by 1 alpha,25(OH)2D3. The present study also suggests that combination treatment with the inhibitor of DNA synthesis and the inducer of differentiation could be beneficial in the clinical therapy of leukemia. The mode of action of clinical low-dose Ara-C treatment is also discussed.

Antibiotics, Antineoplastic↗
PubMed1985

[Assessment of fetal lung maturity by determination of phosphatidylglycerol in human amniotic fluid].

The enzymatic method for the specific quantification of phosphatidylglycerol (PG) and phosphatidylcholine (PC) was described in detail in this paper. Under the present assay conditions, as little as 2 nmoles of PG or PC was accurately measured. The possibility of contamination of cardiolipin and bilirubin in amniotic fluid was eliminated by chromatography on a silicic acid column. Using 275 amniotic fluid samples from uneventful pregnancies, fetal lung maturity was assessed by using a variety of parameters including PG and PC determination. Based on the results of the present investigation, critical concentrations of PG and PC were determined to be 0.36 and 3.0 mumoles/dl, respectively. 239 infants who had more than the critical PG concentration were all associated with normal respiratory function except 3 cases (false-positive rate, 1.3%). 30 out of 36 infants with a PG value lower than this level developed respiratory distress syndrome after birth (false-negative rate, 16.7%). These results indicated that the PG determination was the most accurate predictor of fetal lung well-being prior to birth among the clinical tests so far reported.

Amniotic Fluid↗