Search PubMed⌕ Search

Biomedical subjects

M Oishi

Publications and source records attributed to M Oishi.

At least 199 records · Page 11Linked to original sources
PubMed1991

Poly(ADP-ribose) polymerase inhibitors suppress UV-induced human immunodeficiency virus type 1 gene expression at the posttranscriptional level.

Gene expression of human immunodeficiency virus type 1 (HIV-1) is induced not only by trans activation mediated through a gene product (tat) encoded by the virus but also by treatment of virus-carrying cells with DNA-damaging agents such as UV light. Employing an artificially constructed DNA in which the chloramphenicol acetyltransferase gene was placed under the control of the HIV-1 long terminal repeat, we analyzed the induction process in HeLa cells and found that inhibitors of poly(ADP-ribose) polymerase suppressed UV-induced HIV-1 gene expression but not tat-mediated expression. We also found that suppression occurs at the posttranscriptional level. These results indicate that HIV-1 gene expression is activated by at least two different mechanisms, one of which involves poly-ADP ribosylation. A possible new role of poly-ADP ribosylation in the regulation of specific gene expression is also discussed.

Benzamides↗
PubMed1991

[A case of multiple mononeuropathy associated with pustulosis palmaris et plantaris (PPP)].

A 41-year-old man with PPP since in 1982 was admitted in May, 1987, because of the progressive asymmetric sensory disturbance in the hands and feet over 4 months, accompanied by an exacerbation of PPP. On admission, eruptions of PPP were observed in the palms and soles. Asymmetric and mildly decreased sensations of touch and pain were present in the distal part of the four extremities as well as in his trunk, accompanied by paresthesia and dysesthesia. Mild to moderate weakness was noted in the hand muscles, and slight muscular atrophy was present in the right lower leg. A work-up for collagen vascular disease was within normal limits. T lymphocyte subset showed a decreased ratio of OKT 4/OKT 8. Left sural nerve biopsy showed axonal degeneration and moderate decrease of myelinated fibers, and the vasculitis was not found. The neurological signs and symptoms as well as the skin eruptions improved with methylprednisolone 40 mg/day. A causal relationship between the multiple mononeuropathy and PPP of our patient was indicated by the almost simultaneous onset of the neuropathy and the exacerbation of PPP as well as the improvement of these two conditions with corticosteroid therapy. Such combination of multiple mononeuropathy and PPP has not so far been reported.

Adult↗
PubMed1990

Quantitative analysis of serum IL-6 and its correlation with increased levels of serum IL-2R in HIV-induced diseases.

We have devised a luminescence sandwich ELISA for the quantification of IL-6 in both sera and cell culture supernatants, which had a detection limit of 100 fg/ml of test sample. By using the luminescence sandwich-ELISA, low but measurable levels of IL-6 (9.5 pg/ml on average) were found in the sera from normal individuals. The serum levels of IL-6 were elevated in HIV-seropositive asymptomatic carriers (55.5 pg/ml on average), and the IL-6 levels were correlated with the degree of HIV-induced disease progression (AIDS-related complex 106.8 pg/ml on average and (AIDS 283 pg/ml). IL-6 immunoreactivity in the sera of AIDS patients eluted at a 25,000 m.w. major peak, which was biologically active and heat-stable, and a 500,000 m.w. minor peak in size-exclusion HPLC. Interestingly, a significant correlation was observed between the serum IL-6 levels and soluble IL-2R levels. In vitro, HIV infection of PHA-activated PBMC led to enhanced release of IL-6 into the culture supernatants. Moreover, soluble IL-2R release was markedly increased by adding exogenous IL-6, whereas it was decreased by adding the neutralizing anti-IL-6 mAb to the cultures. These results demonstrate that increased IL-6 levels are significantly associated with sIL-2R levels, and suggest a cause of the increased levels of this receptor in patients with HIV infection. Furthermore, both serum IL-6 and serum IL-2R levels in HIV infection reflect the stage of the HIV-induced disease.

Cells, Cultured↗
PubMed1990

Hair trace elements in cerebellar degeneration: low copper levels in late cortical cerebellar atrophy.

The levels of ten elements in the hair of 7 patients with olivopontocerebellar atrophy (OPCA), 10 patients with late cortical cerebellar atrophy (LCCA) and 1489 healthy persons were determined by inductively coupled plasma emission spectrometry. The phosphorus, zinc, selenium, calcium, magnesium, iron, manganese, aluminium and mercury concentrations did not show any statistically significant difference among the three groups. The copper concentration was significantly lower in the patients with LCCA than in the patients with OPCA, and in the healthy controls. The possibility that LCCA is associated with a mild degree of copper deficiency is considered.

Atrophy↗
PubMed1990

Differential cloning of genomic DNA: cloning of DNA with an altered primary structure by in-gel competitive reassociation.

A procedure was developed for cloning (anonymous) DNA sequences whose primary structures differ between two DNA samples. The procedure is based upon in-gel competitive DNA reassociation after electrophoresis of a mixture of restriction enzyme-digested target DNA (from which clones are to be isolated) and a large excess of unclonable reference DNA (competitor DNA). Inclusion of polyethylene glycol in the reassociation buffer greatly improved the in-gel reassociation efficiency, which was critical for the practical use of the procedure. Using this technique, we obtained several clones from rat brain (target) DNA, which may have been derived from tissue (brain)-specific altered DNA structures. The details of this procedure and its possible applications are discussed.

Animals↗
PubMed1989

Inhibitors for protein-tyrosine kinases, ST638 and genistein: induce differentiation of mouse erythroleukemia cells in a synergistic manner.

In order to investigate the biochemical nature of intracellular cascades leading to cellular differentiation in vitro, we examined the effect of inhibitors of protein phosphorylation on terminal erythroid differentiation of mouse erythroleukemia (MEL) cells. We have found that specific inhibitors of protein phosphorylation at tyrosine residues, ST638 and genistein, effectively induce differentiation in a synergistic manner with an agent which blocks DNA replication such as mitomycin C (MMC). Based upon these findings, the possible involvement of protein phosphorylation (and dephosphorylation) at tyrosine residues in differentiation is discussed.

Animals↗
PubMed1989

Cytoplasmic localization of human repetitive DNA revealed by in situ hybridization.

Previously, we showed that a human repetitive DNA sequence (Sau3A family) belonging to a satellite DNA is unstable and constantly excised from the chromosomes (R. Kiyama, H. Matsui, and M. Oishi, 1986, Proc. Natl. Acad. Sci. USA 83, 4665). The unusual property of the repetitive DNA, along with another repetitive DNA (Alu sequence), was further investigated by in situ hybridization in several different human cells including HeLa, bone marrow, and peripheral blood cells. We found that the excised repetitive DNA sequences are localized not only in nuclei, but also in cytoplasm. These results have confirmed the instability of these DNA sequences in the chromosomes and further suggest that the alpha satellite DNA and the Alu sequence which were excised from the chromosomes are released from nuclei to cytoplasm.

Bone Marrow↗
PubMed1989

A tissue-specific change in repetitive DNA in rats.

From a genomic library constructed from an EcoRI digest of Wistar rat brain DNA, we isolated a clone (BL-1) that gave a 0.6-kilobase restriction fragment only in brain (or lens) DNA upon Southern hybridization. The tissue-specific fragment was present in Wistar and other strains (Sprague-Dawley and Donryu) of rats regardless of their sex and age. Sequencing of the clone indicated that it is closely related to a part of the LINE 3 sequence, one of the highly repetitive sequences present throughout mammalian genomes. Polymerase chain reaction using primer sequences in the BL-1 clone indicated that it is derived from an amplified (rear-ranged) sequence, although other explanations are possible. These results suggest that there are tissue-specific changes in DNA primary structure during mammalian developmental processes.

Animals↗
PubMed1989

Induction of in vitro differentiation of mouse embryonal carcinoma (F9) and erythroleukemia (MEL) cells by herbimycin A, an inhibitor of protein phosphorylation.

Herbimycin A is one of the benzenoid ansamycin antibiotics isolated from a culture of Streptomyces species (Omura, S., A. Nakagawa, and N. Sadakane. 1979. Tetrahedron Lett. 1979: 4323-4326). Recent studies have shown that the antibiotic not only inhibits the phosphorylation of p60src in Rous sarcoma virus- (RSV) infected cells, but also reverses the cellular phenotypes acquired by transfection with tyrosine kinase oncogenes (Uehara, Y., M. Hori, T. Takeuchi, and H. Umezawa. 1985. Jpn. J. Cancer Res. 76:672-675; Uehara, Y., M. Hori, T. Takeuchi, and H. Umezawa. 1986. Mol. Cell. Biol. 6: 2198-2206; Uehara, Y., Y. Murakami, S. Mizuno, and S. Kawai. 1988. Virology. 164: 294-298). These studies and other evidence indicate that the antibiotic inhibits a reaction(s) closely associated with the function of cellular tyrosine kinases. We have found that herbimycin A is an effective inducing agent capable of triggering differentiation in two typical mouse in vitro differentiation systems, which have been considered to be quite different in their mechanism of induction: endoderm differentiation of embryonal carcinoma (F9) cells and terminal erythroid differentiation of erythroleukemia (MEL) cells. The results suggest that there is a common step in the intracellular differentiation cascade which is, directly or indirectly, associated with phosphorylation at specific (tyrosine) residues of cellular proteins. The significance of this finding with respect to the molecular mechanism of in vitro differentiation is discussed.

Animals↗
PubMed1989

Primary intrasellar microgerminoma detected by magnetic resonance imaging: case report.

A case of primary intrasellar germinoma in a 24-year-old woman is presented. Her initial symptoms were diabetes insipidus and headaches. The neurological examination found no abnormalities, but the endocrinological examination disclosed a deficiency in growth hormone secretion. Her skull x-ray revealed a normal sella turcica, and a computed tomographic scan revealed no abnormal mass in the pituitary fossa, but a slightly enlarged stalk. Magnetic resonance imaging revealed a small tumor in the posterior lobe. Transsphenoidal exploration revealed a germinoma in the posterior pituitary lobe. Six cases of primary intrasellar germinoma, including our case, were reviewed. Our case is considered to be the smallest intrasellar germinoma yet reported.

Adult↗
PubMed1989

Cloning and sequencing of two tandem genes involved in degradation of 2,3-dihydroxybiphenyl to benzoic acid in the polychlorinated biphenyl-degrading soil bacterium Pseudomonas sp. strain KKS102.

Two genes involved in the degradation of biphenyl were isolated from a gene library of a polychlorinated biphenyl-degrading soil bacterium, Pseudomonas sp. strain KKS102, by using a broad-host-range cosmid vector, pKS13. When a 3.2-kilobase (kb) PstI fragment of a 29-kb cosmid DNA insert was subcloned into pUC18 at the PstI site downstream of the lacZ promoter, Escherichia coli cells carrying this recombinant plasmid expressed 2,3-dihydroxybiphenyl dioxygenase activity. Nucleotide sequencing of the 3.2-kb PstI fragment revealed that there were two open reading frames (ORFI [882 base pairs] and ORFII [834 base pairs], in this gene order). Results of analysis of Tn5 insertion mutants and unidirectional deletion mutants suggested that the ORFI coded for 2,3-dihydroxybiphenyl dioxygenase. When the sequence of ORFI was compared with that of bphC of Pseudomonas pseudoalcaligenes KF707 (K. Furukawa, N. Arima, and T. Miyazaki, J. Bacteriol. 169:427-429, 1987), the homology was 68%, with both strains having the same Shine-Dalgarno sequence. The result of gas chromatography-mass spectrometry analysis of the metabolic product suggested that the ORFII had meta cleavage compound hydrolase activity to produce benzoic acid. DNA sequencing suggested that these two genes were contained in one operon.

Amino Acid Sequence↗
PubMed1989

Possible alteration of genomic DNA in specific rat tissues.

By employing in gel competitive reassociation, which distinguishes two DNA preparations, to clone anonymous DNA fragments with altered primary structure, we isolated a clone (BL-1) from a rat DNA which gave an extra, apparently altered, DNA band in a specific tissue (brain) when we used it as a probe for Southern hybridization. The sequence of BL-1 was very similar to a portion of LINE, a highly repetitive sequence. Southern hybridization analysis with oligonucleotide probes representing a portion of the BL-1 sequence confirmed the presence of the brain-specific band. Another, different band specific to HindIII digests of heart DNA was also detected with the same oligonucleotide probes. Furthermore, we found that poly (A) +RNA hybridized with BL-1 was enriched in brain. These results suggest that there are tissue specific alteration of genomic DNA in rats which may be associated with transcriptional activation specific to the sequence. Alternative explanations of the results are also discussed.

Animals↗
PubMed1989

Vitamin E status in pediatric patients receiving antiepileptic drugs.

Decreased vitamin E levels have been reported in epileptic children receiving antiepileptic drugs (AED). In order to investigate the tocopherol status of patients receiving AED, the alpha-, beta, gamma- and delta-tocopherol concentrations were each determined in 447 patients' serum samples using a high-performance liquid chromatographic method. In pediatric patient samples (n = 244, aged 1-16 years), there was a negative relationship (p less than 0.02; r = -0.153) between age and alpha-tocopherol levels, while there was a positive relationship (p less than 0.05; r = 0.142) between age and gamma-tocopherol levels. The mean (+/- SD) alpha-tocopherol levels (0.73 +/- 0.23 mg/dl) in the older children (n = 166, aged 7-16 years) were significantly lower (p less than 0.05) than the levels (0.83 +/- 0.23 mg/dl) found in the younger children (n = 78, aged under 7 years). Administration of alpha-tocopherol acetate, 3 mg/kg/day to 8 children and 5 mg/kg/day to 4 children, increased alpha- and total tocopherol levels (p less than 0.01 for both), while gamma-tocopherol levels and serum lipid peroxide levels were decreased (p less than 0.01 for both). In 203 epileptic patient samples (over 16 years of age), the mean alpha-tocopherol level (0.92 +/- 0.28 mg/dl) tended to be lower (p less than 0.1) than in 22 healthy adult controls (1.01 +/- 0.26 mg/dl).

Adolescent↗
PubMed1988

Somatosensory evoked potentials in chronic alcoholics with spasticity.

Somatosensory evoked potentials to median and bilateral tibial nerve stimulation were investigated in eight chronic alcoholics with spasticity, 12 patients with alcoholic polyneuropathy, and 11 normal subjects. Central conduction velocities from the third lumbar vertebra to the fifth cervical vertebra and from the 12th thoracic vertebra to the fifth cervical vertebra were significantly lower in the chronic alcoholics with spasticity than in the alcoholic polyneuropathy group and in the healthy nonalcoholic group. The result indicates that chronic alcoholics with spasticity have conduction disturbance in the posterior column and/or the medial lemniscus, which is considered to be due to alcoholic myelopathy and/or a brainstem lesion.

Alcoholism↗
PubMed1988

Chromosomal localization of Sau3A repetitive DNA revealed by in situ hybridization.

The Sau3A DNA family consists of unique alphoid human repetitive DNA which is prone to be excised from the chromosomes and exhibits restriction fragment length polymorphism. We studied the chromosomal localization of the DNA by in situ hybridization using cultured normal human lymphocytes. Under standard hybridization conditions, the sequence hybridized with the centromeric regions of chromosomes 1, 2, 4, 11, 15, 17, 18, 19 and X, but under high stringency hybridization conditions, it hybridized with the centromeric regions of chromosomes 1, 17 and X, and particularly chromosome 11. Based on these results, we discuss the evolutionary relationship among the sequences of the Sau3A DNA family.

Biological Evolution↗
PubMed1988

Cytoplasmic factors involved in erythroid differentiation in mouse erythroleukemia (MEL) cells.

In order to identify and characterize intracellular factors involved in in vitro differentiation of mouse erythroleukemia (MEL) cells, the differentiation process was analyzed by cell and cytoplast fusion. The results suggested that the process is not a single cascade of molecular chain reactions, but a synergistic result of two different inducible intracellular reactions. One reaction is induced following damage to DNA (inhibition of DNA replication) and is not specific to MEL cells. The other reaction, which is specific to MEL cells, is fully induced by typical erythroid inducing agents such as dimethylsulfoxide or hexamethylenebisacetamide even at concentrations suboptimal for the erythroid induction. Based upon these data, we searched for the putative trans-acting differentiation-inducing factors and detected two proteinaceous factors (DIF-I and DIF-II) in the cytosol fraction which apparently correspond to these reactions. When, partially purified, either one of these factors was introduced into undifferentiated MEL cells, it triggered erythroid differentiation, provided that the recipient cells had been potentiated by the induction of the other reaction. In this article, we summarize the basic characteristics of these cytoplasmic factors involved in erythroid differentiation in MEL cells.

Animals↗