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H Sano

Publications and source records attributed to H Sano.

At least 667 records · Page 37Linked to original sources
PubMed1983

Accumulation of guanine-cytosine-enriched low M.W. DNA fragments in lymphocytes of patients with systemic lupus erythematosus.

The fate of the newly synthesized DNA in peripheral blood lymphocytes from patients with systemic lupus erythematosus was examined. After lymphocytes were stimulated with the mitogen phytohemagglutinin (PHA), DNA was pulse-labeled with radioactive thymidine and was analyzed by sucrose density gradient centrifugation. Two classes of DNA were identified; the main DNA fraction that migrated to the same position as that of control samples, and low m.w. DNA fragments. The low m.w. DNA fragments were further characterized: i) The amount of low m.w. fragments increased with increasing time of culture after PHA stimulation. ii) The guanine cytosine content was 47% of the total bases at 4 days after PHA stimulation. iii) The base composition was similar to that of DNA fragments isolated from DNA/anti-DNA antibody immune complexes. These results lead us to propose that guanine cytosine-enriched low m.w. DNA fragments accumulate in cells after nuclear DNA is degraded, and that these fragments may serve as a primary source of autoantigen for anti-DNA antibody production. In addition, they may interfere with normal cellular metabolism.

Base Sequence↗
PubMed1982

Prospection of chronic vasospasm by CT findings.

Haematoma of the basal cistern was classified into five grades. A little or moderate haematoma (1+ or 2+) disappeared from the basal cistern in 3 or 4 days, however much or severe haematoma (3+ or 4+) remained over a week. Vasospasm occurred in a high number of the cases in which the haematoma was recognized in the basal cistern later than 4 days after SAH not only in operative case but also in conservative case. However vasospasm occurred rarely in cases with early operation within 24 hours after onset except for cases with severe packed haematoma (4+) in the basal cistern.

Adult↗
PubMed1982

Tissue specificity and clustering of methylated cystosines in bovine satellite I DNA.

The positions of all 5-methylcytosine (mC) residues in bovine satellite I DNA were determined by sequence analysis of native purified satellite I DNAs from three bovine tissues as well as from cloned DNA. The EcoRI cleavage units from thymus and liver were found to contain 1,402 residues; that from brain contained 1,401 residues. Satellite I DNA from thymus contained a total of 5.0% mC, whereas that from liver and brain contained 4.4% and 2.6% mC, respectively. Thus, the extent of methylation of this DNA is tissue-specific. So is the location. In each tissue, the location of mCs is nonrandom, consisting of three clusters of heavily methylated regions, each of about 200 bases. However, the extent of methylation within each cluster is tissue-specific. The mCs are located entirely in C-G doublets and primarily in palindromic sequences, C-C-G-G sequences (10 methylatable sites) are almost completely methylated in all tissues examined, but T-G-G-A sequences (16 methylated in all tissues examined, but T-G-G-A sequences (16 metylatable sites) are methylated to different extents in each tissue. Neither the tissue specificity of methylation nor the clustering pattern is detectable by examining only G-C-G-G sites, leading us to emphasize the importance of total sequence determination for genomic DNAs in studies of methylation. The clustering pattern, which is preserved despite a 2-fold difference in mC content between brain and thymus, may indicate a role for DNA methylation in chromatin structure.

5-Methylcytosine↗
PubMed1982

["Methamphetamine-stereotypy and hypermotility" in rats chronically treated with reserpine--the effect of intracerebral injection of chlorpromazine].

In rats given methamphetamine (MAPT, 10 mg/kg i.p.) 24 hrs--48 hrs after the long term-administration of reserpine (RE), we have previously found such "bizarre-biting behaviour" as persistent and bloody biting activity at their own legs and tails or those of their cage mates. The present investigation examined the effect of a blockade of the dopamine receptor in the brain on MAPT-induced "bizarre-biting behaviour" and hypermotility of RE-pretreated rats. Male albino Wistar rats aged 4 weeks were injected intraperitoneally with RE (1.25 mg/kg) or 0.9% saline solution (1.25 ml/kg) every two days for 13 days. Twenty-three hrs after the last injection, rats received chlorpromazine (CP, 150 micrograms, 250 micrograms, 625 micrograms, or 1 mg/rat) intracerebrally by Valzelli's method; and 1 hr later, MAPT (10 mg/kg i.p.) was injected. MAPT-induced hypermotility was potentiated in the RE-pretreated rats, but it was suppressed dose-dependently by CP. Stereotyped licking and biting activities of saline-pretreated rats were completely suppressed by CP at each dose given, however, the "bizarre-biting behaviour" of RE-pretreated rats was inhibited by CP only at high doses (625 micrograms or 1 mg/rat). It is suggested that the MAPT-induced hypermotility of RE-pretreated rats is mediated by activation of dopamine receptor while their "bizarre-biting behaviour" is partially related to it.

Animals↗
PubMed1982

Dna isolated from DNA/anti-DNA antibody immune complexes in systemic lupus erythematosus is rich in guanine-cytosine content.

DNA fragments were isolated from DNA/anti-DNA antibody immune complexes of systemic lupus erythematosus. Hybridization experiments indicated that DNA isolated from immune complexes originates from human nuclear DNA. Two classes of DNA were identified by polyacrylamide gel electrophoresis. The m.w. of small fragments was 25,000 with 30 to 40 base pairs, and that of large fragments was 100,000 with 150 base pairs. The average guanine-cytosine (G-C) content in the small fragments was 55% of total bases, and that in the large fragments was 45%. Compared with the average 38% G-C content of total human DNA, the antigen DNA is rich in G-C content. Such unusually high G-C content can alter DNA structure, which may serve as the target for antibody production.

Antigen-Antibody Complex↗
PubMed1982

Correlation between clinical activity of systemic lupus erythematosus and the amounts of DNA in DNA/anti-DNA antibody immune complexes.

The relationship between clinical activity of systemic lupus erythematosus (SLE) and molecular sizes of DNA fragments isolated from DNA/anti-DNA antibody immune complexes were examined. Among sera from twenty-eight patients with SLE examined, three different molecular sizes of DNA were identified, namely, DNA of m.v. 25,000 with 30 to 50 base pairs (bp); m.w. 100,000 with 150 to 200 bp; and m.w. 200,000 with 300 bp. On the basis of the molecular sizes of DNA fragments, we can divide patients with SLE into four groups. The first group contained DNA predominantly of m.w. 25,000. The second group contained DNA predominantly of m.w. 100,000. The third group contained DNA of m.w. 200,000. The fourth group contained both m.w. 25,000 and 100,000. A method to quantitate the amounts of DNA in DNA/anti-DNA immune complexes was developed. The amount of DNA fragments was estimated by measuring the amount of 32P-phosphate incorporated into 5 ends of DNA. Patients with severe disease tended to have greater amounts of DNA (up to 400 ng/ml serum). Two serial studies also support this result. Thus, the quantitative analysis shows that the amount of DNA in the immune complexes is highly correlated with disease activity (r = 0.864; p less than 0.001). These results suggest that DNA/anti-DNA immune complexes may play some role in the pathogenesis of lupus nephritis.

Adolescent↗
PubMed1981

The mat-1 gene in Chlamydomonas regulates DNA methylation during gametogenesis.

The inheritance of chloroplast genes in Chlamydomonas is regulated by methylation of chloroplast DNA during gametogenesis. The wild-type pattern of maternal inheritance results from the methylation of chloroplast DNA in female (mt+) but not in male (mt-) gametes, leading to preferential degradation of chloroplast DNA of male origin in zygotes. This paper describes the distribution of 5-methyl cytosine residues in restriction fragments of chloroplast DNA sampled during gametogenesis by two methods: ethidium bromide staining of agarose gels, and binding of antibody directed against 5-methyl cytosine onto restriction fragments blotted to nitro-cellulose paper. Methylated cytosines are located in most if not all Eco RI and Msp I fragments, but the extent of methylation is not proportional to fragment size. The mat-1 mutation carried by males converts maternal inheritance. Chloroplast DNA of male gametes carrying the mat-1 mutation becomes methylated during gametogenesis. This methylation protects against restriction enzyme-promoted degradation in zygotes, as shown by physical data demonstrating the transmission to progeny of chloroplast genes carried on chloroplast DNA of the mat-1 male parent. Thus the mat-1 gene, which is linked to the mating-type locus, determines whether or not methylation of chloroplast DNA will occur in males during gametogenesis.

Chlamydomonas↗
PubMed1981

Differential activity of DNA methyltransferase in the life cycle of Chlamydomonas reinhardi.

Two molecular weight forms of DNA (cytosine-5-)-methyltransferase [S-adenosyl-L-methionine:DNA (cytosine-5-)- methyltransferase, EC 2.1.1.37], both active in assays in vitro, were isolated from the green alga Chlamydomonas reinhardi at various stages of the life cycle. The enzyme with Mr 60,000 was found in vegetative cells and gametes of both male (mt-) and female (mt+) mating types. The enzyme with Mr 200,000 was specific to gametic cells and zygotes, which are the only stages at which methylation of chloroplast DNA occurs in vivo. Chloroplast DNA from gametes was shown to be methylated on both strands at most if not all methylation sites and the Mr 200,000 enzyme was shown to methylate both unmethylated and hemimethylated sites, the latter at an elevated rate. Micrococcus luteus DNA showed the same nearest-neighbor frequencies of methylation after methylation by each molecular weight component. The data suggest strongly that the Mr 200,000 enzyme is the active multimeric form of the Mr 60,000 enzyme and that it acts as both initiation and maintenance methylase. It is proposed that methylation of chloroplast DNA in female gametes and zygotes is regulated by assembly of the multimeric Mr 200,000 active enzyme, which in turm determines the maternal inheritance of chloroplast DNA.

Chlamydomonas↗
PubMed1981

Isolation of DNA from DNA/anti-DNA antibody immune complexes in systemic lupus erythematosus.

A low molecular weight DNA fragment was isolated from DNA/anti-DNA antibody immune complexes found in patients with active systemic lupus erythematosus (SLE). Total sera were treated with 40% saturated ammonium sulfate to isolate gamma-globulin fraction and phenolized to partition proteins and nucleic acids. After being treated with RNAase, the sample was labeled at the 5' end with 32P-phosphate and electrophoresed in an 8% polyacrylamide gel, which was dried and autoradiographed. The sample that migrated at positions of molecular weight between 20,000 and 28,000 was susceptible to DNAase I but resistant to S1-nuclease. The data suggest that the immune complexes of SLE patients contain double-stranded DNA with 30 to 40 base pairs.

ABO Blood-Group System↗