Search PubMed⌕ Search

Biomedical subjects

K Okazaki

Publications and source records attributed to K Okazaki.

At least 415 records · Page 23Linked to original sources
PubMed1984

Mitotic activity of prolactin cells in the pituitary glands of male and female rats of different ages.

The anterior pituitary of colchicine-pretreated male and female rats from 20 days to 12 months of age was stained immunohistochemically with anti-rat prolactin serum. Immunoreactive mitotic cells were identified in all groups of rats. In adult female rats the mitotic index of prolactin cells was higher at oestrus than at other stages of the oestrus cycle and than that in male rats of comparable ages. If adult female rats were ovariectomized on the second day of dioestrus or on the day of proestrus, the mitotic indices at presumptive oestrus were less than those in sham-operated controls at oestrus. Estrogen administration to ovariectomized rats significantly elevated the mitotic index of prolactin cells at 48 h after the treatment. The mitotic indices of prolactin cells in female rats reached a peak at 60 days of age, and then decreased with age. In male rats the mitotic indices showed a steady decrease from the value at 20 days of age. A sex difference in the mitotic indices of prolactin cells was noted from 60 days to 12 months of age. The present results clearly demonstrate that differentiated prolactin cells can undergo mitosis and that a sex difference in the mitotic activity of prolactin cells is present during adult life.

Aging↗
PubMed1984

High-level expression and molecular cloning of genes encoding Candida tropicalis peroxisomal proteins.

The development of peroxisomes in the cells of Candida tropicalis grown on oleic acid was accompanied by a markedly high expression of peroxisomal proteins. On the basis of this finding, the nuclear DNA library of this yeast was screened by differential hybridization, and 102 clones of oleic acid-inducible sequences were isolated. Seven coding regions were found to form clusters in three stretches of the genomic DNA. Five of the regions were identified as genes for peroxisomal polypeptides (PXPs). The coding sequence for PXP-2 hybrid selected an additional mRNA for PXP-4, the subunit of long-chain acyl coenzyme A oxidase, which was the most abundant PXP. PXP-2 and PXP-4 were close in apparent molecular weight and generated similar peptides when digested with a protease. The gene for PXP-4 was adjacent to that for PXP-2 on the genome and also hybridized to the mRNA coding for PXP-5. These and other similar results suggest that the genes for the peroxisomal proteins of this organism arose by duplication of a few ancestral genes.

Animals↗
PubMed1984

Expression of a herpes simplex virus glycoprotein in two clonal lines of hamster cells transformed by herpes simplex virus type 2.

Expression of herpes simplex virus type 2 (HSV-2) glycoproteins on the cell surface of two clones of a hamster cell line transformed by HSV-2 was examined by immunofluorescence tests with hamster antisera prepared against three size-class glycoprotein fractions obtained from hamster embryo fibroblast cells infected with HSV-2. Enhanced expression of one of the three size-class glycoprotein fractions (molecular weight, 82,000-94,000) was found in one clone (155-4-213) after replating of the cells, and in the other (155-4-03) after actinomycin D treatment. Enhanced expression of the antigen in clone 155-4-213 was inhibited by 2-deoxy-D-glucose, but not by puromycin or protease inhibitors, antipain and p-nitrophenyl-p'-guanidinobenzoate. On the other hand, the antigen expression induced by actinomycin D in clone 155-4-03 was inhibited by these four drugs. These results indicate that the expressions of the antigen in the two clones are enhanced by different mechanisms.

Animals↗
PubMed1983

Human influenza virus infection in mink: serological evidence of infection in summer and autumn.

During the period from July to November 1981, 42 out of 128 young mink of a flock were found to possess antibodies against the viruses A/Bangkok/1/79 (H3N2) and A/Kumamoto/37/79 (H1N1), which were currently prevailing human influenza viruses. Seroconversion against A/Bangkok/1/79 was found in 12 mink from August to November. HI antibody titers of greater than 1: 128 were found in 8 out of 42 mink at the first examination in July and August. These findings suggest that infection with these human influenza viruses was present in this flock during the period from birth (the beginning of May) to autumn, the non-prevalent season in man. Attempts at virus isolation were unsuccessful.

Animals↗
PubMed1983

Histidine-rich protein as a possible origin of free amino acids of stratum corneum.

The origin of free amino acids and/or their metabolites of the stratum corneum was investigated by pulse-chase experiments using hairless mice. Two, 24, 48, and 72 hrs after the animals were pulse-chased with 3H-histidine or 3H-arginine, radioactivity was determined in the following three fractions of the epidermis: the 0.1 N HClO4 soluble, ethanol soluble fraction (Fr. I); the 0.1N NClO4 soluble, ethanol insoluble fraction (Fr. II); and the 0.1 N HClO4 insoluble, 8M urea soluble fraction (Fr. III). Radioactivity of the epidermal proteins was also determined in SDS-PAGE gels by the gel slicing method. At first, 3H-histidine and/or 3H-arginine were predominantly incorporated into Fr. III, especially into a certain epidermal protein which showed little mobility on SDS-PAGE. Subsequently, 3H, once incorporated into Fr. III, appeared to shift from Fr. III to Fr. II and, simultaneously, from the top band(s) to a band of 32,000 daltons. As a result of amino acid analysis, a protein of Fr. II was considered a histidine-rich protein corresponding to HRP-II of the new born rats of Ball et al. After 48 hrs, as the radioactivities of Fr. III and Fr. II decreased remarkably, Fr. I gradually increased in radioactivity. The major radioactive substances in Fr. I at 72 hrs were identified as 3H-histidine and 3H-urocanic acid when 3H-histidine was used as a tracer, and as 3H-arginine, 3H-ornithine, and 3H-citrulline in the case of 3H-arginine. The amino acid composition of the histidine-rich protein was very similar to that of the free amino acids of the stratum corneum in the hairless mouse, in which some amino acid metabolites were considered as their precursor amino acids. These results strongly suggest that the free amino acids and/or their metabolites of the stratum corneum might be the final products of a degradation of the histidine-rich protein.

Amino Acids↗
PubMed1982

Specificity of trypsin. Cleavage of aspartic acid 101 derivatives of lysozyme by trypsin.

The beta-carboxyl group of Asp 101 was modified with several amine nucleophiles by the amine-carbodiimide procedure and the trypsin susceptibilities of the derivatives were analyzed by peptide mapping. The (aminoethyl)asparaginyl peptide bond was completely cleaved by trypsin but the (3-aminopropyl)asparaginyl bond was not. When the positive charge was in the proper position, large residues such as (2-[imidazol-4(5)-ylmethylamino]ethyl) asparagine or (11-amino-3,-6,9-triazaundecyl)asparagine were susceptible to trypsin.

Amines↗