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Biomedical subjects

M Kurimoto

Publications and source records attributed to M Kurimoto.

At least 271 records · Page 15Linked to original sources
PubMed1989

Identification and purification of the enhancer-binding factor of human immunodeficiency virus-1. Multiple proteins and binding to other enhancers.

The enhancer-binding factor of human immunodeficiency virus (HIV)-1 was purified from human B cells by sequence-specific duplex oligonucleotide affinity chromatography. Gel retardation assay and footprint analysis showed that the purified factor bound specifically to the HIV-1 enhancer sequence, and protected both direct repeats in the HIV-1 enhancer. The purified factor consisted of four main polypeptides of the molecular weight of 36,000-42,000. At least three of them had enhancer-binding activity after elution from sodium dodecyl sulfate-polyacrylamide gel and renaturation. UV cross-linking analysis also showed that at least two of the polypeptides in purified fraction had a binding activity specific for the HIV-1 enhancer. The purified factor activated transcription from the HIV-1 promoter in vitro, confirming that it was indeed a transcription factor for HIV-1. The purified factor also recognized sequences in the immunoglobulin kappa gene enhancer and the major histocompatibility complex class I gene enhancer with almost the same affinity as the HIV-1 enhancer. These results suggested the existence of multiple proteins which recognize the kappa B-related sequences. This regulatory factor should help in the study of the biochemical pathway underlying HIV production from latently infected cells.

Base Sequence↗
PubMed1989

Biological and immunological properties of Sugi basic protein-pullulan conjugate. I. Suppressive effect on IgE antibody production and on IgE-mediated reactions.

Sugi basic protein (SBP), a major allergen of Japanese cedar pollen, conjugated to pullulan acquires suppressive activities for IgE, but not for IgG antibody production, and for IgE-mediated PK reactions in a SBP-specific manner. When either normal or IgE anti-SBP antibody-producing mice were treated with the conjugate, IgE anti-SBP antibody levels scarcely increased even after immunization with SBP + alum. This suppression was shown to be SBP specific and IgE selective. The ability of SBP-pullulan conjugate to elicit PK reactions on passively sensitized rat skin was markedly reduced. Furthermore, the conjugate inhibited the reactions mediated by the IgE antibodies and native SBP when it was injected into the IgE antibody-sensitized sites 2 h prior to SBP challenge. The reduced ability of the conjugate to elicit PK reactions was not due to loss of antigenic determinants during the conjugation procedures because binding activity of the conjugate to anti-SBP antibodies was as strong as that of native SBP. These results indicate that SBP-pullulan conjugate may be useful for 'desensitization therapy' against the pollinosis.

Allergens↗
PubMed1988

N-terminal amino acid sequence of a major allergen of Japanese cedar pollen (Cry j I).

A purified preparation of a major allergen of Japanese cedar pollen, sugi basic protein (SBP, Cry j I), was separated into 5 subfractions of 50-45 kDa. All of the SBP subfractions were confirmed to be reactive to IgE antibodies from patients with Japanese cedar pollinosis, and also to mouse anti-SBP monoclonal antibodies. The sequences of 20 N-terminal amino acids of these 5 subfractions were found to be identical. Peptide mapping analyses of the SBP subfractions showed similar patterns, with some differences which might in part be due to the existence of an N-linked carbohydrate chain. The N-terminal amino acid sequence of SBP was identical to the reported sequence of an allergen of mountain cedar which vegetated in North America.

Allergens↗
PubMed1988

Enhancement of human immunodeficiency virus production by natural lymphotoxin.

The effect of natural lymphotoxin (n-LT) on CD4+ MOLT-4 cells and those cells producing human immunodeficiency virus (HIV), MOLT-4/HIVHTLV-IIIB cells, was studied. Four days after treatment with n-LT, a significant cytotoxic/cytostatic effect was observed predominantly on MOLT-4/HIVHTLV-IIIB cells. Furthermore, with regard to the production of HIV, an almost 3- to 5-fold increase of viral particles was observed in MOLT-4/HIVHTLV-IIIB cells 6 h after treatment with n-LT. These data indicate the possibility that this cytotoxic factor is one of the responsible molecules in the pathogenesis of the acquired immunodeficiency syndrome (AIDS).

Antibodies, Monoclonal↗
PubMed1988

Natural human interferon-gamma derived from lipopolysaccharide-stimulated human myelomonocytic HBL-38 cells.

A human myelomonocytic cell line, HBL-38 cells, propagated in vivo, spontaneously produced interferon (IFN)-gamma and IFN-alpha. Whereas hemmagglutinating virus of Japan (HVJ) enhanced the production of IFN-alpha, bacterial lipopolysaccharide (LPS) markedly enhanced the production of IFN-gamma. LPS could be replaced with lipid A. Furthermore, the enhancement of production of IFN-gamma by LPS was completely abolished by polymixin B. IFN-gamma derived from LPS-stimulated HBL-38 cells was purified to homogeneity and characterized. The apparent molecular weight, subspecies composition, amino acid sequence and glycosylated sites were in agreement with those of the product of normal human peripheral blood lymphocytes (PBL). These results indicate that the myelomonocytic HBL-38 cells, not a T-cell line, can also produce IFN-gamma identical to the product of normal human PBL.

Amino Acid Sequence↗
PubMed1987

Synergism between human tumor necrosis factor and human interferon-alpha: effects on cells in culture.

The cytostatic and cytotoxic effects of highly purified natural human tumor necrosis factor (HuTNF-alpha) and natural human interferon-alpha (HuIFN-alpha) on 23 cell lines were studied in vitro. Natural HuTNF-alpha showed cytostatic and cytotoxic effects on PC-9, KHG-2, HT-1197, KG-1 and L-929 cells, and HuIFN-alpha showed both effects on KHG-2 and Daudi cells. A mixture of HuTNF-alpha and HuIFN-alpha (1:1, by unit) showed cytostatic and cytotoxic effects on HuTNF-alpha- or HuIFN-alpha-resistant cell lines such as KB, KATO-III, HEp-2, P-4788, as well as on HuTNF-alpha- or HuIFN-alpha-susceptible cells. Thus, the combined preparation of HuTNF-alpha and HuIFN-alpha expanded the spectrum of sensitive cells. The dosage of the mixed preparation required to produce 50% inhibition of cell growth was less than 20% of that of HuTNF-alpha or HuIFN-alpha alone. These results indicate that the cytostatic and cytotoxic effects of HuTNF-alpha and HuIFN-alpha are synergistically enhanced when they are administered together.

Cell Division↗
PubMed1987

[A case of tuberous sclerosis associated with a pineal region tumor].

The authors report a rare case of tuberous sclerosis associated with pineal region mixed glioma. A 38-year-old woman with tuberous sclerosis, who had a past history of left nephrectomy and tumorectomy of the right kidney for bilateral renal angiomyolipomas, was admitted because of headache and ataxic gait. CT scan and cerebral angiography suggested a pineal region tumor. Suboccipital craniectomy and partial removal of the tumor was performed via infratentorial supracerebellar approach. Microscopic examination revealed mixed oligodendroglioma and astrocytoma. It is well known that tuberous sclerosis is occasionally associated with brain tumors. However, with few exceptions, these have been subependymal giant cell astrocytomas in the lateral ventricles. They seem to originate from subependymal nodules of hamartomatous nature. As far as we are aware, association of pineal region tumor with tuberous sclerosis as in this case has not been reported.

Adult↗
PubMed1986

The expression of human tumor necrosis factor in E. coli.

cDNA of human natural TNF (n-TNF) obtained by stimulating human leukemic B cell line (Ball-1) with Sendai virus was cloned. Valine-started-TNF (V-TNF) gene was constructed from the cDNA and expressed in E.coli HB101 under the control of a trp promoter by the induction of 3-indoleacrylic acid. The expression level of V-TNF clone was about 10% of the total E.coli protein. On the other hand, the expression level of glutamine started-TNF (Q-TNF) gene having the same SD-ATG sequence which was constructed from V-TNF gene was as low as about 1/20 of that of V-TNF. The nucleotide sequence around ATG (-4 approximately +12) of Q-TNF gene was randomly changed without modifying the coded amino acid sequence, resulting to obtain high expression clones as similar TNF protein yield as that of V-TNF. These clones possessed A residue rich sequence around the initiation codon ATG. These results show that some correlation might exist between the high expression rate and A residue rich sequence around the initiation codon.

Amino Acid Sequence↗
PubMed1986

[Antineoplastic effects and mechanism of action of IFN-alpha on brain tumors with use of fluorescent isothiocyanate-labelled IFN].

The antineoplastic effects and mechanism of IFN-alpha with a newly designed fluorescent isothiocyanate-labelled IFN-alpha were studied on three established glioma-cell lines and cultured cells of clinical brain tumors. Viability, cell cycle and cells showing positive reaction with fluorescent isothiocyanate-labelled IFN were analyzed by flow cytometry. U373MG glioma cells in contact with 10(4) IU/ml of IFN for 24 hours had a dose dependency, decreased viability, S-phase block in the cell cycle and high rate of positive reaction with fluorescent isothiocyanate-labelled IFN. Two surgical cases, except for one case, showed similar results and other cell lines or meningiomas were not affected by IFN. As the antineoplastic effects of IFN-alpha correlated with the rate of occurrence of positive cells with fluorescent isothiocyanate-labelled IFN, sensitive tumor cells may have a respective specific receptor for IFN-alpha, and, therefore, fluorescent isothiocyanate-labelled IFN-alpha might be of clinical value with regard to the problem of the receptor as well as sensitivity test.

Adenoma↗
PubMed1986

A sensitive radioimmunoassay for alpha-interferon: circulating alpha-interferon-like substance in the plasma of healthy individuals and rheumatoid arthritis patients.

A radioimmunoassay for circulating alpha-interferon (IFN alpha) has been developed using lymphoblastoid IFN alpha. The assay was specific for IFN alpha, and did not cross-react with IFN beta, IFN gamma, or ACTH, while it was specifically inhibited by recombinant IFN alpha. The radioimmunoassay (y) correlated linearly with the virus inhibition assay (x), with a regression line of y on x of y = 0.659x + 245 (u) (P less than 0.01). alpha-Interferon-like substance (IFN alpha-LS) was extracted and concentrated from plasma either by silicic acid or by antibody immunoadsorption. Serial dilutions of plasma and extracted samples of plasma showed dilution curves identical to those of standard IFN alpha, suggesting the presence of endogenous IFN alpha in human plasma. The circulating IFN alpha-LS of healthy individuals aged 20 to 45 was 0.207 +/- 0.055 ng/ml in males (n = 48) and 0.172 +/- 0.076 ng/ml in females (n = 34). Gel filtration studies on a Sephadex G-75 column suggested that circulating IFN alpha-LS exists in a fragmented form, inactive in virus inhibition assays, in the plasma of healthy individuals. The finding may help explain why biological IFN alpha is often undetectable in the plasma of healthy donors, yet is detectable by radioimmunoassay. Circulating IFN alpha-LS in the plasma of healthy individuals declined gradually with age. IFN alpha-LS was significantly decreased in the plasma of rheumatoid arthritis patients, when compared with the value found in the age and sex-matched healthy controls and in osteoarthritis patients (P less than 0.0001). The decrease was related neither to treatment nor to disease activity. IFN alpha-LS was, however, not decreased in the plasma of vasculitis patients. Decreased IFN alpha-LS in rheumatoid arthritis may be important from pathogenetic and therapeutic standpoints.

Adult↗
PubMed1985

Effect of lymphotoxin-like substance (OH-1) on metastatic tumor proliferation.

The effect of a lymphotoxin-like substance, OH-1, released by human acute lymphatic leukemia BALL-1 cells, on metastatic tumor proliferation was investigated in BDF1 mice with transplanted Lewis lung carcinoma cells. Mitomycin-C, cyclophosphamide and adriamycin were used as control agents. The effect of OH-1 on metastases, as determined by comparison of the numbers of pulmonary nodules and by 3H-thymidine labeling indices, was significant. Also, investigation of the effect of OH-1 on host immunity showed that, while the control preparations had considerable side effects, immunodepression and emaciation were not noted with OH-1. As to direct cytotoxicity, OH-1 is principally cytostatic in activity and effects cell progression delay in both the G1 and G2 phases.

Animals↗
PubMed1984

[Antitumor effect of new lymphokine OH-1 on BDF1 mice bearing Lewis lung carcinoma].

Antitumor effect of new lymphokine extracted from BALL-1 cells derived from human acute lymphocytic leukemia was investigated using BDF1 mice bearing Lewis lung carcinoma. This antitumor lymphokine is called OH-1. The antitumor effect of OK-1 on transplanted main tumor was great, but less effective than cyclophosphamide. However, the antitumor effect on OH-1 on metastatic tumor was comparably high as with cyclophosphamide, both macroscopically and functionally.

Animals↗