Search PubMed⌕ Search

Biomedical subjects

K Takimoto

Publications and source records attributed to K Takimoto.

At least 91 records · Page 5Linked to original sources
PubMed1985

Purification and properties of myo-inositol-1-phosphatase from rat brain.

myo-Inositol-1-phosphatase [EC 3.1.3.25] was purified from a cytosolic fraction of rat brain. The purified enzyme appeared homogeneous on SDS-polyacrylamide gel electrophoresis and its molecular weight was estimated to be 29,000. The molecular weight of the native enzyme was 55,000 as determined by molecular sieve chromatography. These values indicated that the native enzyme was composed of two identical subunits. The isoelectric point of the enzyme was 4.6. The enzyme hydrolyzed inositol-1-phosphate, 2'-AMP, 2'-GMP, beta-glycerophosphate, and alpha-glycerophosphate; the ratio of the reaction rates was 100 : 84 : 73 : 64 : 32. The Km values for inositol-1-phosphate, 2'-AMP, and beta-glycerophosphate were 1.2 X 10(-4) M, 1.9 X 10(-4) M, and 7.7 X 10(-4) M, respectively. Mn2+ and Ca2+ were strong competitive inhibitors against Mg2+, with Ki values of 3 microM and 20 microM, respectively. This result suggests that myo-inositol-1-phosphatase might be regulated by intracellular Ca2+ and/or Mn2+. Li+, which is known to show a therapeutic effect on manic-depressive disease and also to prolong the intrinsic periods of circadian rhythms in various organisms, was a potent uncompetitive inhibitor and inhibited 50% of the activity at 1 mM. The possibility that myo-inositol-1-phosphatase and inositol phospholipid metabolism are involved in circadian rhythm oscillation is discussed in terms of Li actions.

Animals↗
PubMed1983

Effects of accumulation of phosphocreatine on utilization and restoration of high-energy phosphates during anoxia and recovery in thin hippocampal slices from the guinea pig.

Effects of accumulation of phosphocreatine (P-creatine) on utilization and restoration of high-energy phosphates during anoxia and recovery were studied using thin hippocampal slices from the guinea pig. Incubation of slices with creatine (5 to 30 mM) increased the content of tissue P-creatine, in a linear fashion, and these increases depended on the concentration of creatine and the incubation period to as long as 3 h. Concentration of ATP in the slices was not altered. A high concentration of tissue P-creatine (40 to 100 mmol/kg protein) accumulated by incubation with creatine reduced the rate of ATP exhaustion during anoxia whereas P-creatine itself was rapidly decreased. During reoxygenation after anoxia, concentrations of ATP and P-creatine rapidly recovered in slices preincubated with creatine. Concentrations of P-creatine previously exhausted during anoxia increased to 100 mmol/kg protein after 25 min of reoxygenation whereas the concentration was 35 mmol/kg in the control slice. Elevation of the concentration of P-creatine may therefore prolong the survival time of brain tissue during anoxia and facilitate recovery during reoxygenation.

Adenosine Triphosphate↗
PubMed1983

Lack of enhanced mutation of UV- and gamma-irradiated herpes virus in UV-irradiated CV-1 monkey cells.

The frequency of forward mutation of unirradiated, UV-irradiated or gamma-irradiated herpes virus was determined after infecting UV-irradiated or unirradiated CV-1 monkey kidney cells, to investigate the correlation between UV-enhanced reactivation (UVER) and mutagenesis. UV-irradiation to cells had no effect on mutation frequency of irradiated virus even in the conditions in which UVER was maximally expressed for the survival of UV-irradiated virus.

Animals↗
PubMed1983

Lack of enhanced reactivation of simian virus 40 irradiated with van de Graaff electrons in U.V.-irradiated CV-1 monkey cells.

Simian virus 40 (SV40) irradiated with U.V. or van de Graaff electrons was assayed on CV-1 monkey cells irradiated with U.V. before virus infection. U.V.-irradiated cells enhanced the survival of U.V.-irradiated virus, while little or no enhancement was observed for electron-irradiated virus assayed on U.V.-irradiated cells. It is suggested that the U.V.-irradiated cells are able to increase the repair of U.V.-damaged viral DNA, but not of electron-damaged DNA.

Animals↗
PubMed1980

Estimation of RBEs of thermal neutrons and reactor beam in the thermal neutron field for biomedical purposes.

The radiation field and reactor beam were prepared to measure the RBE of thermal neutrons and reactor beam in Kyoto University Reactor (KUR). The RBE of reactor beam with low contamination of gamma ray (1.8 x 10(11) n cm-2R-1) and high Cd ratio (5000) on HeLa cells was 1.26 at the surviving fraction of 0.90, and the estimated RBE of thermal neutrons was 5.50 at the same surviving fraction.

Cadmium↗
PubMed1976

Craniofacial growth in complete unilateral cleft lip and palate: a roentgeno-cephalometric study.

This study investigated craniofacial growth in unilateral complete clefts using lateral roentgenographic cephalograms. The cleft sample was composed of 135 males and 120 females aged four, six, eight, ten, twelve and eighteen years. Control subjects included 120 non-cleft males and 120 non-cleft females of similar age to the cleft subjects. The cleft group differed from the control group in several major respects: (1) Their over-all growth trend showed a more downward or vertical direction; (2) The cranial base angle was more flattened; (3) The maxilla was smaller and was located in a more posterior and upward position; (4) Ramal height was shorter and the gonial angle was more obtuse. Chin position was generally retrognathic; (5) Skeletal profile showed less convexity; (6) Upper face height was less and lower face height was greater; (7) Both upper and lower central incisors showed a marked lingual inclination; (8) Females in both groups matured about two years earlier than did males. Underdevelopment in both the maxilla and the mandible was more pronounced in cleft females than in cleft males.

Adolescent↗