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Biomedical subjects

Y Takeshima

Publications and source records attributed to Y Takeshima.

84 records · Page 5Linked to original sources
PubMed1991

Intranasal administration of His-D-Trp-Ala-Trp-D-Phe-LysNH2 (growth hormone releasing peptide) increased plasma growth hormone and insulin-like growth factor-I levels in normal men.

The effects of intranasal and iv administration of His-D-Trp-Ala-Trp-D-Phe-LysNH2 (GHRP) on plasma GH, PRL, LH, FSH, TSH, cortisol, insulin, IGF-I as well as GHRH-like immunoreactivity (LI) levels were examined in 6 healthy male subjects. An iv bolus injection of GHRP(1 micrograms/kg BW) caused a remarkable increase in plasma GH levels with a mean (+/- SE) peak of 54.9 +/- 4.2-micrograms/L. In addition an intranasal administration of GHRP resulted in a significant, dose-related increase in plasma GH with peaks of 39.6 +/- 15.3 micrograms/L at a dose of 30 micrograms/kg BW, 14.1 +/- 5.0 micrograms/L at 15 micrograms/kg BW and 7.5 +/- 5.7 micrograms/L at 5 microgram/kg BW. Plasma PRL and cortisol levels were slightly but significantly increased after iv administration of GHRP, whereas GHRP totally failed to affect plasma TSH, LH, FSH, insulin, blood sugar and GHRH-LI levels. Seven consecutive, intranasal administrations of 15 micrograms/kg BW GHRP every 8h were well tolerated in all subjects examined. During this treatment, GH responsiveness to GHRP was not attenuated by desensitization and plasma IGF-I was increased from 94.5 +/- 5.8 micrograms/L before GHRP to 125.8 +/- 6.0 micrograms/L after repeated GHRP administration. These findings indicate that intranasal administration of GHRP stimulates GH secretion and consequently enhances IGF-I production in normal subjects. If GHRP is demonstrated to be beneficial in the treatment of some patients with GH deficiency, the intranasal route of administration may be more useful than the painful injection because a prolonged period is required for the treatment.

Administration, Intranasal↗
PubMed1991

Chemically-synthesized gene encoding modified human superoxide dismutase: its construction, expression and properties of the product.

The gene encoding modified human superoxide dismutase (h-SOD) with 153 amino acid residues was constructed by chemical synthesis using the phosphoramidite method. The gene was designed so as to use bacterial codons for expression in prokaryotes and to introduce several unique restriction sites for further mutagenesis by the cassette exchange method. The distance between Shine-Dalgarno sequence and initiation codon was adjusted to maximum expression by using synthesized oligonucleotide. In addition, Cys 6 of h-SOD was changed to Ala to improve instability of native h-SOD. Synthesized structural gene of h-SOD was expressed in E. coli after induction of isopropyl beta-D-thiogalactoside by inserting the gene into the expression vector pKK223-3 having tac promoter. The gene that has 10 base pairs between Shine-Dalgarno sequence and initiation codon showed the most efficient expression. The gene produced three active SOD isomers as revealed by chromatofocusing. The main isomer was purified to homogeneity and characterized. The h-SOD-Ala6 showed similar properties to those of native h-SOD with respect to molecular weight, subunit structure, absorption spectrum, but the modified SOD was more resistant to heat denaturation than was native h-SOD; half-denaturing temperature was shifted by 10 degrees C. Thus, the exchange of Cys 6 to Ala of h-SOD increased a stability of the enzyme.

Amino Acid Sequence↗
PubMed1990

Influence of electrical stimulation of the hypothalamus on ovarian steroidogenesis in hypophysectomized and adrenalectomized rats.

The effects of electrical stimulation of the lateral hypothalamic area (LHA), periventricular arcuate nucleus (ARC) and ventromedial hypothalamic nucleus (VMH) on the rates of 14C transfer from 14C-1 acetate into ovarian steroids in ovarian slices of hypophysectomized and adrenalectomized (H-A) rats were investigated. The 14C transfer rates into estrogen and 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P) were decreased by LHA stimulation. The stimulation of the ARC and VMH increased the rates of 14C transfer into estrogen, progesterone and 20 alpha-OH-P. From these results, it might be suggested that these hypothalamic structures were involved in the regulation of ovarian steroidogenesis without participation of the pituitary and adrenal.

20-alpha-Dihydroprogesterone↗
PubMed1987

Influence of microinjection of glucagon into ventromedial hypothalamus on acetate metabolism in liver slices of rabbit.

Glucagon was injected directly into the ventromedial hypothalamic nuclei (VMH) of rabbits, and changes in hepatic acetate metabolism were studied. The injection of 3 ng glucagon into the VMH of intact rabbits increased the rates of 14C transfer from 14C-1-acetate into CO2, glucose and ketone bodies but decreased those into cholesterol ester, triglyceride, free cholesterol, free fatty acids and phospholipids. However, after glucagon injection into the VMH of rabbits with VMH lesions and the parietal cortex of intact rabbits, hepatic acetate metabolism did not differ from that of the control rabbits, which received saline injection into the same brain regions. These observations support the hypothesis that the VMH are parts of a glucagon-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMed1986

Influence of microinjection of insulin into hippocampus on hepatic acetate metabolism in rabbits.

Insulin was injected directly into the dorsal hippocampus (DHPC) of rabbits, and changes in hepatic acetate metabolism were studied. The injection of 50 microU insulin into the DHPC decreased the rates of 14C transfer from 14C-1-acetate into glucose and ketone bodies, and increased 14C transfer into cholesterol ester, triglyceride, free cholesterol and free fatty acids. But after insulin injection into the DHPC of rabbits with lesions of dorsal fornix (DFX), hepatic acetate metabolism did not differ from that of control rabbits, which received saline injection into the same brain region. From these results it might be suggested that the DHPC are parts of insulin-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMedDate not supplied

p53 mutations in lung cancers from non-smoking atomic-bomb survivors.

Tobacco smoke contains many carcinogens and has been linked with the development of lung cancer. We sequenced the conserved regions of the p53 tumour suppressor gene in lung cancers from 17 non-smokers from Hiroshima, Japan; 9 were atomic-bomb survivors. The mutations were predominantly transitions (all G:C to A:T); there were no G:C to T:A transversions. By contrast, lung cancers from 77 Japanese smokers have a predominance of G:C to T:A transversions in which the guanine residues occur on the non-transcribed DNA strand. These findings further implicate tobacco smoke carcinogens in the molecular pathogenesis of lung cancer.

Adult↗
PubMedDate not supplied

A case of multiple ovarian cysts in a prepubertal girl with severe hypothyroidism due to autoimmune thyroiditis.

Some children with profound and long-standing hypothyroidism present with signs of paradoxical sexual maturation. In females, it is characterized by breast development, vaginal bleeding, lack of pubic hair, and delayed bone age. A case of multiple ovarian cysts in a prepubertal girl with severe hypothyroidism due to autoimmune thyroiditis is reported. A 7-year, 8-month-old girl presented with precocious puberty and vaginal bleeding. A pelvic ultrasound revealed markedly enlarged ovaries with numerous cysts which disappeared dramatically after thyroid replacement. When large multiple ovarian cysts with vaginal bleeding are found in a prepubertal girl who has a retarded bone age, the possibility of associated hypothyroidism should be considered. Health care providers should keep this in mind because this constellation of symptoms can be completely reversed with the initiation of thyroid replacement.

Child↗