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Biomedical subjects

T Seki

Publications and source records attributed to T Seki.

At least 595 records · Page 33Linked to original sources
PubMed1986

Occurrence and neonatal development of N-terminal (1-15) immunoreactivity of big gastrin in the rat antrum.

G34N (1-15) immunoreactive cells and C-terminal tetrapeptide immunoreactive cells in the antrum of rats of various ages were studied immunocytochemically in both naturally weaned and non-weaned conditions. Some of the C-terminal immunoreactive cells were found to lack G34N (1-15) immunoreactivity while the remainder showed both types of immunoreactivity. G34N (1-15)/C-terminal immunoreactive cell rates increased with age and reached adult values at 3 weeks after birth. The rates in a non-weaned condition were, however, significantly lower than those in a naturally weaned rats. These findings suggest that the development of G34N (1-15) immunoreactivity in rat antral gastrin cells is closely related to maturation of the gastrin cells, and weaning may enhance the maturation process.

Aging↗
PubMed1986

In vitro effect of vasoactive intestinal polypeptide and peptide histidine isoleucine on prolactin secretion by the bullfrog pituitary gland.

The effects of vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) on the in vitro secretion of prolactin (PRL) by the pituitary gland of bullfrogs (Rana catesbeiana) were studied. Pituitary glands were incubated in 67% Eagle's minimum essential medium containing [3H]leucine in the presence or absence of VIP (10(-8)-10(-6) M) or PHI (10(-7)-10(-6) M). Prolactin in the medium and pituitaries was measured by a homologous radioimmunoassay. In addition, PRL synthesis during incubation was monitored by measuring radioactivity of [3H]leucine incorporated into PRL in the medium and pituitaries. Both peptides stimulated release and synthesis of PRL in vitro.

Animals↗
PubMed1986

Effect of thyrotropin-releasing hormone and dopamine on the in vitro secretion of prolactin by the bullfrog pituitary gland.

Pituitary glands of bullfrogs (Rana catesbeiana) were incubated in medium containing thyrotropin-releasing hormone (TRH) and/or dopamine in order to see their effects on the release and synthesis of prolactin, which was measured by a homologous radioimmunoassay. Prolactin synthesis was measured by monitoring the incorporation of [3H]leucine into prolactin. TRH (0.1-10 ng/ml) stimulated the release of immunoassayable prolactin and newly synthesized [3H]prolactin into the medium in a dose-dependent manner; however, it was ineffective in increasing total prolactin (medium plus pituitary) and the incorporation of [3H]leucine into the total prolactin during the experimental period (20 hr). The TRH-induced elevation of prolactin release was suppressed by the addition of dopamine (5 X 10(-7) M) to the medium.

Animals↗
PubMed1986

A fly, Drosophila melanogaster, forms 11-cis 3-hydroxyretinal in the dark.

All-trans and 11-cis 3-hydroxyretinals were synthesized and the presence of these substances in the head of Drosophila melanogaster was shown by using high performance liquid chromatography. Even when the head extract was prepared in the dark from the flies reared successively in the dark, both of the 3-hydroxyretinal isomers were detected. In the culture medium, they were not present. D. melanogaster must have an 11-cis 3-hydroxyretinal forming-system that does not need light.

Animals↗
PubMed1986

Molecular diversity of HLA-DR4 haplotypes.

Complementary DNA (cDNA) clones encoding beta chains of the DR and DQ regions and alpha chains of the DQ region were isolated and sequenced from four homozygous DR4 cell lines of different HLA-D types: GM3103(Dw4), FS(Dw10), BIN(Dw14), and KT3(Dw15). When compared with each other and with a previously published sequence from a DR4 (Dw13 cell line), the variability of DR beta 1 gene products is generally restricted to the region around amino acid position 70, with an additional polymorphism at position 86. Many of these differences, including an unusual amino acid substitution at position 57 in the Japanese cell line KT3(Dw15), may be due to gene conversion events from the DR beta 2 or DX beta genes. In contrast, DR beta 2 molecules are identical in Dw15, Dw10, and Dw4 cell lines. DQ beta chains isolated from GM3103(Dw4), FS(Dw10), and BIN40(Dw14) are also identical. However, the DQ beta sequence from cell line KT3(Dw15) differs substantially from all other previously reported DQ beta alleles, consistent with its serological designation, DQ "blank." The first domain sequences of DQ alpha chains were identical in all four cell lines. The data suggest that relatively circumscribed amino acid changes in the DR beta 1 molecule are responsible for the HLA-D typing differences between some haplotypes.

Base Sequence↗
PubMed1986

Construction of lactose-assimilating and high-ethanol-producing yeasts by protoplast fusion.

The availability of a yeast strain which is capable of fermenting lactose and at the same time is tolerant to high concentrations of ethanol would be useful for the production of ethanol from lactose. Kluyveromyces fragilis is capable of fermenting lactose, but it is not as tolerant as Saccharomyces cerevisiae to high concentrations of ethanol. In this study, we have used the protoplast fusion technique to construct hybrids between auxotrophic strains of S. cerevisiae having high ethanol tolerance and an auxotrophic strain of lactose-fermenting K. fragilis isolated by ethyl methanesulfonate mutagenesis. The fusants obtained were prototrophic and capable of assimilating lactose and producing ethanol in excess of 13% (vol/vol). The complementation frequency of fusion was about 0.7%. Formation of fusants was confirmed by the increased amount of chromosomal DNA per cell. Fusants contained 8 x 10 to 16 x 10 mug of DNA per cell as compared with about 4 x 10 mug of DNA per cell for the parental strains, suggesting that multiple fusions had taken place.

Journal Article↗
PubMed1986

Fenvalerate-induced granulomatous changes in rats and mice.

Wistar rats and ddY mice were fed diet containing 10 to 3000 ppm technical fenvalerate for the major portion of their life span. Microgranulomatous changes were observed in lymph nodes, liver and spleen of both rats and mice as well as in adrenals of rats. The no-effect level for microgranulomatous changes was 30 ppm for mice and 150 ppm for rats. Transmission electron microscopy of phagocytes in the granulomatous foci revealed needle- or rod-shaped crystalline bodies within the cytoplasm. To examine reversibility of the microgranulomatous changes, ddY mice were fed the diet containing technical fenvalerate at the levels of 1000 and 3000 ppm for 6 weeks, followed by rearing on the control diet for up to 12 months. The size and number of the microgranulomatous changes were reduced with time. The microgranulomatous changes were typical of foreign body granulomas; they did not have the appearance of granulomas formed in response to immunologic stimulus.

Adrenal Glands↗
PubMed1986

Pharmacokinetic study of deuterium-labelled coenzyme Q10 in man.

The pharmacokinetics of coenzyme Q10 (CoQ10) in man was studied by utilizing deuterium-labelled coenzyme Q10 (d5-CoQ10). The absence of an isotope effect in the disposition of d5-CoQ10 in man was confirmed from the plasma concentration time curves after simultaneous oral dosing of d5-CoQ10 and unlabelled CoQ10. After oral administration of 100 mg of d5-CoQ10 to 16 healthy male subjects, the mean plasma CoQ10 level attained a peak of 1.004 +/- 0.370 micrograms/ml at 6.5 +/- 1.5 h after administration, and the terminal elimination half-life was 33.19 +/- 5.32 h. In most of the subjects, plasma d5-CoQ10 showed a second peak at 24 h after dosing. This unusual plasma level curve was well described by a newly proposed compartment model based upon the assumption that absorbed CoQ10 is taken up by the liver and then transferred mainly to VLDL and redistributed from the liver to the systemic blood.

Administration, Oral↗
PubMed1985

Estimation of catecholamines by ion-exchange chromatography on Asahipak ES-502C, using glycylglycine as the post-derivatizing agent.

The estimation of catecholamines in human urine was carried out by ion-exchange chromatography on a column of a weakly acidic ion exchanger with an hydrophilic matrix. The catecholamines were first adsorbed onto Amberlite CG-50 (buffered at pH 6.5 with 0.4 M phosphate buffer) and selectively eluted by 0.66 M boric acid solution. They were then separated from impurities that responded to fluorometric detection by isocratic elution from a column of Asahipak ES-502C, a cross-linked vinyl alcohol copolymer with carboxymethyl groups, at 60 degrees C. The mobile phase was 0.05 M sodium succinate buffer pH 5.25 containing 0.015 M borate and 0.5 mM ethylenediaminetetraacetate. Isoproterenol was used as the internal standard; epinephrine, norepinephrine, isoproterenol and dopamine were eluted in this order. One sample could be analyzed every 35 min. The detection limits were 0.2 ng for epinephrine and norepinephrine, 0.6 ng for dopamine. The elution pattern was quite reproducible; the elution volumes of the catecholamines had not changed after 500 determinations.

Catecholamines↗
PubMed1985

Separation of ascorbic acid, dehydroascorbic acid, diketogulonic acid and glucose by isocratic elution from a column of a hydrophilic gel.

High-performance liquid chromatography on an Asahipak GS-320 hydrophilic gel column with tartrate buffer (0.015 M, pH 3.0) containing 2 mM ethylenediaminetetraacetate and 0.05% beta-thiodiglycol as the eluent allowed the separation of glucose, diketogulonic acid, dehydroascorbic acid and ascorbic acid within 30 min. Fluorimetric monitoring of these compounds in the eluate with benzamidine at alkaline pH and at 90 degrees C in the presence of potassium sulphite allowed the determination of nanogram amounts of ascorbic acid, dehydroascorbic acid and diketogulonic acid. This method was applied to the determination of ascorbic acid in fruit juice.

2,3-Diketogulonic Acid↗