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Biomedical subjects

H Nishimura

Publications and source records attributed to H Nishimura.

At least 109 records · Page 6Linked to original sources
PubMed1990

Characterization of the cord-like structures emerging from the surface of influenza C virus-infected cells.

When HMV-II cells (a human malignant melanoma cell line) infected with a newly isolated influenza C strain (Yamagata/1/88) were examined by simple light microscopy, it was found that a large number of cord-like structures which had lengths up to about 500 microns or greater were emerging from the cell surface. The existence of viral glycoproteins (hemagglutinin-esterase, HE) on the surface of these huge structures was confirmed by hemadsorption experiments with erythrocytes from a variety of species as well as by immunofluorescent staining with anti-HE monoclonal antibody. Furthermore, electron microscopy revealed that numerous filamentous particles in the process of budding, each covered with a layer of surface projections approximately 13 nm in length, aggregated with their long axes parallel to form a cord-like structure visible under a light microscope. An electron-dense layer, which presumably consists of membrane protein (M), was seen in cross-sections of all filamentous virions whereas internal nucleocapsids were rarely seen. SDS-polyacrylamide gel electrophoresis of the purified cords also showed that they contained HE and M polypeptides but not nucleoprotein, confirming that long filamentous particles are mostly devoid of nucleocapsids. The emergence of cords on the cell surface was observed in various cell cultures infected with C/Yamagata/1/88 though their number and length varied markedly depending on cell type. The production of cord-like structures was also evident in HMV-II cells infected with any of several different influenza C strains, which suggests that the cord formation is a common feature of influenza C virus group.

Adsorption↗
PubMed1990

Flow cytometric analysis of cellular DNA content in ovarian cancer.

A total of 169 paraffin-embedded tissue sections from 42 patients with epithelial ovarian cancer were subjected to analysis of cellular DNA content by flow cytometry. Twenty-three cases were found to be homogenously diploid, whereas 19 cases were aneuploid. A "mosaic" type containing both aneuploid and diploid cell populations was found in 11 of 19 aneuploid cases. Clinical features showed significant correlation with tumor ploidy of FIGO stage and bulky disease. In evaluation of the prognostic value of tumor ploidy, "mosaic" tumors were frequently observed in women who died of disease (DOD), whereas women with diploid tumors survived longer than those with "mosaic" tumors. The present results suggest that determination of DNA heterogeneity may be a valuable parameter in the prognosis of epithelial ovarian cancer.

DNA↗
PubMed1990

Enhancing effects of Ro 15-1788 on straw-climbing behavior as measured with the straw-suspension method: reversal by diazepam.

Ro 15-1788 (0.5, 1, 5, or 20 mg/kg), a pure benzodiazepine receptor antagonist, was studied for its effect on the duration of immobility and the number of straw-climbing attempts in a modified forced-swim test with straw-suspension of rats. A single dose of 20 mg/kg of Ro 15-1788 injected IP prolonged only the duration of immobility with no effect on straw-climbing behavior, whereas both doses of 1 and 5 mg/kg of this compound significantly enhanced the number of straw-climbing attempts in an inverted U-shaped manner. Ro 15-1788 at 1 mg/kg significantly reversed the inhibitory effect of 1 mg/kg of diazepam on the number of straw-climbing attempts. It is suggested that the enhancing effect of low doses of Ro 15-1788 on straw-climbing behavior can be regarded as an index of its anxiogenic effect, by acting via central benzodiazepine receptors.

Animals↗
PubMed1990

Cephalexin concentrations in human serum, gingiva, and mandibular bone following a single oral administration.

1. Cephalexin concentrations in human serum, gingiva, and mandibular bone after a single oral administration of cephalexin (500 mg) were measured by the paper disc method. 2. The peak times of serum, gingiva, and mandibular bone were approximately 90, 120 and 120 min, respectively. 3. The peak concentrations of serum, gingiva, and mandibular bone were 10.58 micrograms/ml, 5.57 micrograms/g and 2.12 micrograms/g, respectively. 4. The concentration ratio of gingiva/serum and mandibular bone/serum peak time of serum were 0.47 and 0.18, respectively. 5. Cephalexin concentrations in gingiva and mandibular bond did not exceed the MIC80s for clinically isolated strains of Staphylococcus aureus spp., alpha-Streptococci and Peptostreptococcus spp.

Adolescent↗
PubMed1990

Effects of major histocompatibility complex on autoimmune disease of H-2-congenic New Zealand mice.

Autoimmune-prone NZB mice mainly produce IgM-class anti-DNA antibodies and mild SLE develops later in life. The F1 hybrid of NZB and non-autoimmune NZW mice (NZB/W F1 mice) develop a more fulminant SLE, associated with decreases in IgM class, and, in turn, increases in IgG class anti-DNA antibodies. To elucidate the role of the H-2 complex in this mode of anti-DNA antibody production, we established and studied H-2-congenic New Zealand mice, i.e. NZB, NZW, and NZB/W F1 mice with either the homozygous H-2z/H-2z or H-2d/H-2d haplotype or the heterozygous H-2d/H-2z haplotype. The data showed that: (i) although the non-H-2-linked NZB gene(s) seems to determine the IgM anti-DNA antibody production in NZB mice, the effect of this gene is fully expressed only in the case of the H-2d/H-2d homozygous state. (ii) The production of IgG anti-DNA antibodies observed in NZB/W F1 hybrid mice is restricted to the H-2d/H-2z heterozygosity. (iii) Because both NZB and NZW mice with the H-2d/H-2z haplotype produce a lower titer of IgG anti-DNA antibodies than do the NZB/W F1 mice, other complementary non-H-2-linked genetic elements from both NZB and NZW parents are required. The development of lupus nephritis correlated well with that of anti-DNA antibodies. Thus, H-2d/H-2z heterozygosity is a necessary but not sufficient condition for the development of autoimmunity in NZB/W F1 mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Monoclonal antibodies to epitope of CD45R (B220) inhibit interleukin 4-mediated B cell proliferation and differentiation.

A mAb, ALP-2, produced by immunizing rats with proliferating lymph node cells from MRL/Mp-lpr/lpr mice, had an inhibitory effect on recombinant interleukin 4 (rIL-4)-mediated proliferation and differentiation of murine B cells. Kinetic analysis revealed that the ALP-2 exerted these inhibitory effects at an early phase of B cell proliferation and differentiation. Nevertheless, the proliferative response of thymocytes to rIL-4 was not inhibited by ALP-2. In addition, ALP-2 inhibited neither the B cell proliferation induced by interleukin 2 nor the B cell differentiation by interleukin 5. Cross-inhibition experiments, together with immunoblotting analysis, revealed that the LP-2 recognized by ALP-2 appears to be an epitope of CD45R (B220) molecule(s), the isoform(s) of the Ly-5 antigen system. Epitope mapping analysis using CD45 gene transfectants showed that Lp-2 epitope is dependent upon the expression of the first alternatively spliced exon of CD45 gene. Functional studies showed that the mAb to an epitope of CD45R, RA3-2C2, but not RA3-6B2, had similar inhibitory effects on the IL-4-mediated proliferative response of B cells. These findings suggest that the CD45R molecules associated with Lp-2 and RA3-2C2 epitopes are probably related to a signal transduction provided by IL-4 in B cells. The possibility that different pathways are operative for IL-4-mediated signaling between B and T cells has to be considered.

Animals↗
PubMed1990

Monoclonal antibody (VII-M31) to bovine factor VII: a specific epitope in the gamma-carboxyglutamic acid domain.

A murine monoclonal antibody (designated VII-M31) directed against bovine factor VII was prepared and characterized. Antibody VII-M31 inhibited the activations of both factors IX and X catalyzed by factor VIIa in the presence of tissue factor, phospholipids, and Ca2+. It possessed a strong affinity for factor VII in the presence of 5 mM Ca2+ (Kd = 1.12 x 10(-10)M). The immunoblotting test of other bovine proteins with the antibody, such as prothrombin, factor X, factor IX, protein C, protein S, and protein Z, in addition to human factor VII, revealed that it recognizes only a Ca2(+)-dependent epitope in bovine factor VII. Furthermore, this antibody VII-M31 covalently coupled with Affi-Gel allowed a simple and rapid purification of bovine factor VII. To localize the antigenic site in factor VII, various segments including a gamma-carboxyglutamic acid (Gla)-domainless protein, a Gla-domain peptide and the fragments isolated from the lysyl endopeptidase digest, were prepared. Among them, the isolated Gla-domain peptide and Gla-domainless factor VII were no longer recognized by antibody VII-M31, indicating that the sequence around the cleavage site by a-chymotrypsin is required for the interaction between the antibody and factor VII. In accordance with this result, the antibody bound specifically to a Gla-containing peptide corresponding to the NH2-terminal 23-50 residues of factor VII, which contains the chymotryptic cleavage site. These results suggest that the specific epitope of this antibody is localized in the carboxy-terminal 28 residues of the Gla-domain constituting the amino-terminal portion of bovine factor VII.

1-Carboxyglutamic Acid↗
PubMed1990

Circumspinal decompression for thoracic myelopathy due to combined ossification of the posterior longitudinal ligament and ligamentum flavum.

Ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the ligamentum flavum (OLF) in the thoracic spine can result in serious myelopathy, leading to circumferential compression of the spinal cord in advanced stages of the disease. The authors performed circumspinal decompression (circumferential decompression of the spinal cord) on these patients. This operation consists of two steps: posterior and lateral decompression of the spinal cord by removal of the OLF (first step) and anterior removal of the OPLL for anterior decompression (second step), followed by interbody fusion. In the first step, two deep parallel gutters, covering the extent of the OPLL to be removed anteriorly, are drilled down from the rear into the vertebral body along both sides of the dura to easily and safely remove the OPLL anteriorly at the second step. In the second step, the surgical approach varies according to the affected level; costotransversectomy in the upper thoracic spine and standard thoracotomy in the middle or lower thoracic spine. According to the authors, circumspinal decompression is not an easy procedure, but from their results in 10 patients, they identify it as a radical and promising surgical procedure.

Adult↗
PubMed1990

Regulation of thiamine biosynthesis in Saccharomyces cerevisiae.

A pho6 mutant of Saccharomyces cerevisiae, lacking a regulatory gene for the synthesis of periplasmic thiamine-repressible acid phosphatase activity, was found to be auxotrophic for thiamine. The activities of four enzymes involved in the synthesis of thiamine monophosphate were hardly detectable in the crude extract from the pho6 mutant. On the other hand, the activities of these enzymes and thiamine-repressible acid phosphatase in a wild-type strain of S. cerevisiae, H42, decreased with the increase in the concentration of thiamine in yeast cells. These results suggest that thiamine synthesis in S. cerevisiae is subject to a positive regulatory gene, PHO6, whereas it is controlled negatively by the intracellular thiamine level.

Acid Phosphatase↗
PubMed1990

Human malignant melanoma cell line (HMV-II) for isolation of influenza C and parainfluenza viruses.

HMV-II, a human malignant melanoma cell line, was compared with other cell lines (MDCK, Vero, and LLC-MK2) and primary cultures of monkey kidney (PMK) cells for the isolation and quantification of influenza and parainfluenza viruses. HMV-II cells were superior to MDCK and LLC-MK2 cells in quantification of the influenza C virus and were used successfully in the isolation of the virus from clinical specimens. The HMV-II cell line was also more sensitive for isolating parainfluenza viruses from clinical specimens than were Vero and PMK cells; there was, however, no significant difference in the quantification of the viruses among these cultures. As far as influenza A and B viruses were concerned, the HMV-II cell line was significantly less sensitive than MDCK cells, and no virus was isolated from clinical specimens with HMV-II cells. Thus, HMV-II cells are useful for the isolation of influenza C and parainfluenza viruses as an alternative to embryonated hen's eggs and PMK cells.

Animals↗
PubMed1990

Changes in insulin receptor kinase with aging in rat skeletal muscle and liver.

To see if insulin receptor kinase activity alters with aging, the activity of wheat germ agglutinin-purified receptor preparations from liver and skeletal muscle was compared in 2-, 4-, 10-, and 20-mo-old rats. Basal and insulin-stimulated autophosphorylation of liver insulin receptor and its kinase activities toward histone 2b and poly(Glu4Tyr1) did not alter with aging. On the other hand, the muscle insulin receptor showed different results. Insulin-stimulated increases of autophosphorylation and the kinase activity toward histone 2b above basal were comparable in the four groups. However, insulin-stimulated phosphorylation of poly(Glu4Tyr1) was decreased in 20-mo-old rats compared with 10- and 4-mo-old rats. These results indicate that insulin receptor kinase activity could vary under certain conditions, depending on the substrate used to measure the activity. It is concluded that insulin receptor kinase activity does not change markedly during the process of aging, although subtle changes seem to exist.

Adenosine Triphosphate↗
PubMed1990

Endothelium-dependent L-Arg- and L-NMMA-sensitive mechanisms regulate tone of brain microvessels.

Pial arterioles on the surface of the mouse brain were observed via television microscopy and measured with an image-splitting technique. The vessels were dilated by L-arginine (L-Arg) in concentrations as low as 10(-5) M and were constricted in dose-dependent manner by NG-monomethyl-L-arginine (L-NMMA). Both the dilation and the constriction were abolished by endothelial damage. This damage was produced over a short segment of endothelium by a well-established technique that involves exposing the endothelium to a helium-neon laser in the presence of intravascular Evans blue dye. In arterioles that were responsive to 10(-5) M L-Arg, five other L-amino acids, also at 10(-5) M, failed to have any effect. The data provide direct evidence for the endothelium-dependent nature of the responses to L-Arg and L-NMMA in vivo in a defined segment of the cerebral vasculature. L-NMMA inhibited dilation by either L-Arg or acetylcholine. The data are consistent with data from in vitro studies and from studies demonstrating that L-NMMA acutely raises blood pressure. From all these earlier studies it has been hypothesized that there is a continuously acting, endothelium-dependent, L-Arg-dependent, and L-NMMA-inhibitable mechanism tending to relax blood vessels. The mediator of this mechanism is thought to be the endothelium-dependent relaxing factor for acetylcholine. Our data suggest that this mechanism is acting in the resistance vessels of the brain in vivo.

Acetylcholine↗
PubMed1990

Angiotensin II binding sites in aortic endothelium of domestic fowl.

In domestic fowl, angiotensin II (ANG II) produces a unique vasodepressor response in vivo and endothelium-dependent relaxation of aortic rings in vitro that appear to be a direct effect on vascular smooth muscle mediated through vascular angiotensin receptors. To explore the possible role of the endothelium in ANG II-induced vasodilation, ANG II binding to aortic membrane fractions and intact endothelium and prostaglandin (PG) production were examined in fowl aortas. 125I-[Ile5]ANG II binding by endothelium-intact aortic membrane fractions was consistently higher than binding by identically prepared endothelium-deleted membrane fractions at virtually all concentrations of ligand (10 pM-0.20 microM). Incubation of intact aortic rings with 125I-[Ile5]ANG II (0.50 nM) resulted in specific endothelial binding that increased linearly with time from 5.5 +/- 1.7 (SE) fmol/mg protein at 5 min to 13.7 +/- 1.8 at 30 min. Endothelial ANG II binding increased linearly with the dose of ligand, from 2.7 +/- 0.3 fmol/mg protein at 0.1 nM to 21.0 +/- 2.2 at 1.0 nM. Specific ANG II binding to aortic endothelium was competitively displaced 73 +/- 11% by unlabeled ANG II (0.1 microM) but not by bradykinin (0.1 microM). Incubation of intact aortic rings with [14C]arachidonic acid resulted in the formation of radioactive metabolites that comigrated in thin-layer chromatography with authentic PGE2 but not with 6-keto-PGF1 alpha. PGE2 production by aortic rings (44.4 +/- 4.5 ng.mg dry tissue-1.h-1) was not stimulated by addition of ANG II. These results suggest that specific receptors for ANG II exist in fowl aortic endothelium and that PGs are not involved in ANG II-induced vasodilation of the fowl aorta.

Angiotensin II↗