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Biomedical subjects

K Higashi

Publications and source records attributed to K Higashi.

At least 343 records · Page 19Linked to original sources
PubMed1984

Inhibition of ATPase activity of the recA protein by ATP ribose-modified analogs.

The single-stranded, DNA-dependent ATPase activity of purified recA protein was found to be inhibited competitively by ribose-modified analogs of ATP, 3'-O-anthraniloyl-ATP (Ant-ATP), and 3'-O-(N-methylanthraniloyl)-ATP (Mant-ATP). The Ki values for Ant-ATP and Mant-ATP were around 7 and 3 microM at pH 7.5, respectively. The inhibitions by these analogs were much stronger than that by ADP, which is also a competitive inhibitor for the ATPase activity of the recA protein. The Ki value for ADP is 76 microM. Ant-ATP and Mant-ATP reduced the Hill coefficient for ATP hydrolysis and thus contributed to the cooperative effect of ATP.

Adenosine Triphosphatases↗
PubMed1984

Thyroid antibodies in healthy blood donors.

The frequency of thyroid antibodies was investigated in 1314 healthy blood donors. Twenty-three of 870 males (2.6%) were positive for thyroglobulin antibody (TA), 34 (3.9%) for thyroid microsomal antibody (MA) and 19 (2.2%) for both TA and MA. Thirty-four of 484 females (6.2%) were positive for TA, 46 (9.5%) for MA and 29 (6.0%) for both TA and MA. Eighty-six of 1314 blood donors were positive for TA and/or MA. There was no difference in liver function tests between AAT and controls. In females, the incidence of thyroid antibodies tended to increase with age. However, the subjects aged under 19 showed another peak of incidence of thyroid antibodies. The values of total T4, T3 and free T4 were not different between 86 subjects with positive thyroid antibodies (asymptomatic autoimmune thyroiditis, AAT) and 86 sex- and age-matched controls without thyroid antibodies, whereas serum TSH of AAT was significantly higher than that of controls. Nine of 86 (10.5%) subjects with AAT had apparently increased basal TSH level.

Antibodies↗
PubMed1984

A case of pseudohypoparathyroidism (PHP) associated with multiple hormonal abnormalities.

A case of pseudohypoparathyroidism (PHP) associated with several hormonal abnormalities in addition to parathyroid hormone (PTH) was reported. Several endocrinological examinations before and after treatment with 1 alpha-OH-D3 revealed abnormal thyroid stimulating hormone and prolactin responses to thyrotropin releasing hormone, abnormal plasma renin activity responses to renin stimulation test, and abnormal calcitonin responses to calcium infusion test. These abnormalities were not corrected when serum calcium levels returned to normal after therapy. From these results, it was suggested that in PHP resistance to multiple hormones that worked by stimulating adenylate cyclase might be the cause of these hormonal abnormalities, irrespective of serum calcium levels.

Adult↗
PubMed1984

[A case of subependymoma of the septum pellucidum].

A 72-year-old-female was admitted because of slight disorientation and urinary incontinence. CT scan on admission revealed isodensity mass in the portion of the septum pellucidum and dilated lateral ventricle with patcy enhancement. A patient underwent the right frontal osteplastic craniotomy and subtotal removal of the tumor. Microscopical examination of the removed tumor tissue revealed a typical finding of subependymoma. In the previous literature subependymoma of the septum pellucidum has been reported only seven cases. We reported a rare case of subependymoma derived from the septum pellucidum, and histopathology and symptomatology of the tumor were discussed with the literature.

Aged↗
PubMed1983

Purification and characterization of myosin light-chain kinase from porcine myometrium and its phosphorylation and modulation by cyclic AMP-dependent protein kinase.

Myosin light-chain kinase was purified from porcine myometrium to apparent homogeneity at about 262-fold with an Mr of 130 000 as determined by SDS-polyacrylamide gel electrophoresis and a sedimentation coefficient of 4.5 S. The approximate content of the soluble myosin light-chain kinase was estimated to be about 0.85 microM. The purified enzyme exhibited strict substrate specificity only for 20-kDa myosin light chain and Ka values of 0.6 nM and 0.3 microM for calmodulin and Ca2+, respectively. The enzyme was phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase, which resulted in a decrease in the affinity for calmodulin of 4-7-fold without effect on the Vmax. The maximal amount of phosphate incorporated into the enzyme was 0.5-0.8 and 1.0-1.4 mol per mol of the enzyme in the presence and absence of Ca2+ and calmodulin, respectively. In the presence of a subsaturating concentration of calmodulin, the enzyme showed a lower sensitivity for Ca2+ by phosphorylation.

Animals↗
PubMed1983

Recognition of the ribosomal RNA structures by purified nucleolar RNA methyltransferase.

Previously we have isolated the specific RNA methyltransferase from the nucleoli of Ehrlich ascites tumor cells. The purified enzyme was found to be specific for methylation of C5 position of cytosine residue in ribosomal RNA in vitro (Obara, 1982b). In the present study, we have investigated the recognition mechanisms of RNA structure by this enzyme from the points of view of both primary and secondary structures. Analysis of in vitro methylation product by ribonuclease T1 digestion indicated the methylation-site(s) was limited to a certain number of nonanucleotide. The next experiments with either Sl nuclease or actinomycin D and ethidium bromide suggested that the enzyme modified only cytidine residue in or located close to the double stranded part of RNA. On the other hand, the characterization of analogues of cytidine residue in the RNA at molecular level showed that the methylation of rRNA was inhibited by either cytidine, CDP or CTP, but little inhibition was observed in the presence of cytosine, 5-methylcytidine and CMP.

Animals↗
PubMed1983

Isolation of immunochemically distinct form of cytochrome P-450 from microsomes of tulip bulbs.

A highly purified cytochrome P-450 was obtained from the microsomes of tulip bulbs (Tulipa gesneriana L.). The molecular weight (Mr = 52,500) and amino acid composition of this plant cytochrome P-450 are similar to those reported for rat livers. On the contrary, Ouchterlony double diffusion analyses indicated that cytochrome P-450 isolated from tulip bulbs shares no common antigenic determinants with those of 9 other plants, in spite of the presence of comparable contents of cytochrome P-450 and/or trans-cinnamate 4-monooxygenase with tulip bulbs.

Amino Acids↗