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Biomedical subjects

H Watabe

Publications and source records attributed to H Watabe.

At least 91 records · Page 5Linked to original sources
PubMed1988

Elevation of serum alpha-fetoprotein and proliferation of oval cells in the livers of LEC rats.

Alpha-fetoprotein (AFP) in the sera of 35 LEC (Long-Evans with a cinnamon-like coat color) rats between 7 and 25 weeks of age was evaluated by enzyme-linked immunosorbent assay (ELISA). Elevation of serum AFP and proliferation of oval cells in the liver were observed in most LEC rats, which suffered from acute hepatitis. On the other hand, the serum AFP level was within the normal range before the onset of hepatitis. Immunohistochemical staining for AFP revealed that some of the proliferating oval cells produced AFP. Morphometric analysis of AFP-positive cells and ELISA for serum AFP demonstrated that there was a statistically significant correlation between the number of AFP-positive cells in the liver and the concentration of AFP in the serum. Histological examination revealed the transition and differentiation of the oval cells to small hepatocytes. These results suggested that the phenomena which occurred in LEC rats suffering from acute hepatitis were similar to those that occurred during the early stage of azo dye hepatocarcinogenesis, although the extent of the oval cell proliferation and the elevation of serum AFP in LEC rats were not as great as those in rats treated with azo dye. This is the first report on a rat strain with proliferation of AFP-producing oval cells during its natural history.

Animals↗
PubMed1988

[Purification of prostatic acid phosphatase and prostate specific antigen from human seminal plasma].

Prostatic acid phosphatase (PAP) and prostate specific antigen (PA), which are useful markers of diagnosis for prostatic cancer, have been purified from human seminal plasma. Total of 54.4 mg PAP and 3.0 mg PA were purified from 426.5 ml human seminal plasma. The purified antigens were demonstrated a single band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), having a molecular weight of about 50,000 and 34,000, respectively. The PAP and PA purified from human seminal plasma were considered similar to that of prostatic tissue immunologically and biochemically.

Acid Phosphatase↗
PubMed1987

Studies on new antibiotics SF2415. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

A new species of Streptomyces is described for which the name Streptomyces aculeolatus is proposed. The organism produces new antibiotics SF2415A1, A2, A3, B1, B2 and B3 active against Gram-positive bacteria. Empirical molecular formulae of the antibiotics SF2415A1, A2, A3, B1, B2 and B3 were determined to be C26H31N2O5Cl, C26H30N2O5, C26H30N2O5Cl2, C26H33O5Cl, C26H32O5 and C26H32O5Cl2, respectively.

Animals↗
PubMed1985

[Enzyme activities in cultured fetal rat hepatocytes].

Several enzymes of amino acid and carbohydrate metabolism were studied in primary cultures of fetal rat hepatocytes. One day after plating, activity of both esterase and gamma-glutamyl transpeptidase decreased to half of the freshly isolated hepatocytes, and then remained constant. Acid phosphatase revealed lower activity after plating but recovered to the same levels of isolated cells on day-8. Leucine aminopeptidase and glutathione S-transferase showed a peak of activity respectively on day-6 and day-8. On the other hand, activities of glucose-6-phosphate dehydrogenase, hexokinase and pyruvate kinase increased linearly from Day-1, but only pyruvate kinase reached a plateau on Day-2. These results suggest that different patterns of enzyme activities in the culture might be a reflection, both of a release from homeostatis and adaptation to a new environment.

Acid Phosphatase↗
PubMed1985

Occurrence of cytotoxic autoantibody in rabbits by immunization with heterologous liver arginase: a possible implication in the mechanism of the autoimmune liver diseases.

Rat liver arginase was isolated from extracts of liver in a pure form. Monospecific antisera raised against the arginase reacted with arginase of liver but not with arginase of kidney, spleen, heart, lung, testis and brain. The antisera were, however, reactive with liver arginase of a variety of animals, including human, mouse, sheep, horse and cow as well as rabbit, a homologous animal used for immunization. The rabbit autoantibodies showed direct cytotoxic activity as well as antibody-dependent cell-mediated cytotoxicity to homologous rabbit hepatocytes. Immunocytochemical electron microscopic examination showed that the arginase was localized on the surfaces of rat hepatocytes and on intracellular organelles. These results suggest that liver arginase could be an important antigen of the liver with implications for the pathogenesis of autoimmune liver diseases.

Animals↗
PubMed1984

On the nucleotide sequence recognized by a eukaryotic site-specific endonuclease, Endo.SceI from yeast.

Endo.SceI which is isolated from cells of Saccharomyces cerevisiae is a eukaryotic site-specific endonuclease active on double-stranded DNA. At each cleavage site, Endo.SceI cuts only a defined phosphodiester bond in each strand of the double helix. We compared nucleotide sequences around five cleavage sites for Endo.SceI using a computer. We could not find any common specific sequence consisting of five base pairs or more among them. However, we found a 26-base pair consensus sequence which included 15 conserved nucleotides, allowing any of the five sequences to include a few nucleotides deviated from the consensus sequence. The consensus sequence is 5'-CAn*PYnnAnnCYYGTTnnnPnYnnYA-3', where P, Y, n, and * denote purine, pyrimidine, any nucleotide, and the center of the cleavage site, respectively. The numbers of sites at which the consensus sequence appears in pBR322 DNA, phi X174 replicative form DNA, fd replicative form DNA, or SV40 DNA are close to those of the cleavage sites for Endo.SceI. We found that a 33-base pair fragment was efficiently cut at the defined phosphodiester bonds by Endo.SceI. This 33-base pair fragment included 25 base pairs out of the 26-base pair consensus sequence. The fragments in which a part of the consensus sequence was missing were not cut by Endo.SceI. These observations suggest that the consensus sequence described above is the major characteristic around the cleavage sites recognized by Endo.SceI and that the mode of recognition of cleavage sites by Endo.SceI is different from that by restriction endonucleases. We found homology between the consensus sequence for Endo.SceI and the sequences around the cleavage sites for two other site-specific endonucleases of S. cerevisiae: Endo.SceII and YZ-Endo which is involved in mating type switching.

Base Composition↗
PubMed1984

Purification of a eukaryotic site-specific endonuclease, Endo.Sce I, from Saccharomyces cerevisiae and effectors on its specificity and activity.

A site-specific endonuclease (Endo.Sce I) which caused double-strand scission of DNA was highly purified from a eukaryote, Saccharomyces cerevisiae IAM4274. The molecular weight of the active form of Endo.Sce I was estimated to be 120,000 and 110,000 by sedimentation analysis on a glycerol density gradient and gel filtration on Ultrogel AcA34, respectively. Analysis of the fractions from the last column chromatography by polyacrylamide gel-electrophoresis in the presence of sodium dodecyl sulfate and by an assay of the endonucleolytic activities suggested that Endo.Sce I consists of two non-identical subunits with molecular weights of 75,000 and 50,000. Unlike restriction endonucleases, Endo.Sce I was active on chromosomal DNA of the cells which produced Endo.Sce I. Single-stranded DNA was not cleaved by Endo.Sce I, but inhibited the endonucleolytic activity of the enzyme on double-stranded DNA. The endonucleolytic activity of Endo.Sce I required the magnesium ions (Mg2+) as a sole cofactor; Mg2+ could not be replaced by Ca2+ or Zn2+. When Mg2+ was replaced by manganese ions (Mn2+), extensively purified Endo.Sce I cleaved double-stranded DNA at many other sites in addition to the sites at which DNA was cleaved in the presence of Mg2+. Experiments indicated that this is not the activation of contaminating endonuclease in the preparation of Endo.Sce I, but the result of relaxation in the site-specificity of cleavage.

Base Sequence↗
PubMed1983

A new class of site-specific endodeoxyribonucleases. Endo.Sce I isolated from a eukaryote, Saccharomyces cerevisiae.

We had found that yeasts had intracellular endodeoxyribonucleases that cut phage DNA into a set of double-stranded fragments with discrete chain lengths. We purified one of them to apparent homogeneity from Saccharomyces cerevisiae and designated it Endo.Sce I. Sequence analysis around 5 cleavage sites in plasmid DNA and phage DNA revealed that Endo.Sce I cuts a defined phosphodiester bond in each strand of double helix at the cleavage sites and produces free cohesive ends consisting of 4 nucleotides protruding at 3'-termini. However, unlike in the case of prokaryotic type II-restriction endonucleases, (i) Endo.Sce I seems to consist of two nonidentical subunits, (ii) no common palindrome or consensus sequence including more than 5 base pairs is detected at or near these cleavage sites, and (iii) Endo.Sce I can cut the DNA isolated from the cells that produced Endo.Sce I. All of the 5 cleavage sites are included in inverted repeats, but these inverted repeats are variable in size, nucleotide sequence, and distance between repeating units. An inverted repeat itself is not a structure recognized by Endo.Sce I. This study shows that Endo.Sce I is the first example of eukaryotic site-specific endonuclease and has properties, as described above, which distinguish it from prokaryotic restriction endonucleases.

Base Sequence↗
PubMed1980

Further characterization of IgG receptors from human placenta.

A Cell membrane fraction from term human placenta was prepared by homogenization and ultracentrifugation. The fraction was found to bind both human IgG and human serum albumin. Maximal specific binding occurred at pH 5.2, and the amount of binding was dependent upon incubation time, temperature, buffer, and ionic strength. The binding of human serum albumin was inhibited by preincubation with H-IgG but the reverse did not happen.

Binding, Competitive↗