Search PubMed⌕ Search

Biomedical subjects

T Nishihara

Publications and source records attributed to T Nishihara.

At least 199 records · Page 11Linked to original sources
PubMed1990

Actions of TNF and IFN-gamma on angiogenesis in vitro.

We have developed a model system for studying angiogenesis in which microvascular fragments and myofibroblasts (Mf) isolated from lipid tissues are grown in co-culture. We have found that Mf induce capillary formation by producing an endothelial cell growth factor and by secreting an extracellular matrix that causes endothelial cells to form a cordlike structure. This system appeared to be well suited for examining the effects of vasoactive substances such as the TNF and INF-gamma on capillary growth. TNF-alpha,beta, and IFN-gamma not only significantly inhibited capillary growth induced by Mf, but also blocked capillary development induced by fibroblast growth factors (FGF), well-known potent angiogenic factors. Recently, we have found that platelet-derived growth factor (PDGF) enhances in vitro capillary formation, probably at least in part by acting on Mf. Just as with FGF, capillary growth in the presence of PDGF was almost completely blocked by IFN-gamma. We examined the mode by which IFN-gamma inhibits angiogenesis and found that IFN-gamma inhibits both the proliferation of endothelial cells and collagen(s) synthesis by Mf. These actions of TNF or IFN-gamma could limit vascular formation in solid tumors.

Animals↗
PubMed1990

Antimicrobial activities of thiolactomycin against gram-negative anaerobes associated with periodontal disease. f1.

Thiolactomycin (TLM), (4R)-(2E,5E)-2,4,6-trimethyl-3-hydroxy-2,5, 7-octatriene-4-thiolide, purified from a culture filtrate of a strain of the Nocardia species, was examined for antimicrobial activities against more than 100 strains of oral and periodontally associated bacteria. Nine other commonly used antibiotics were also included for the test. We found that TLM exhibited strong and selective antimicrobial activities against Bacteroides gingivalis and other oral black-pigmented Bacteroides species that may be etiologically associated with adult periodontitis. TLM also inhibited the growth of Actinobacillus actinomycetemcomitans, but did not affect the growth of oral streptococcal species and Eubacterium species. Strains of Eikenella corrodens were moderately susceptible to TLM, while Actinomyces viscosus strains were only slightly susceptible to it. Other antibiotics used for comparison showed a broad spectrum of antimicrobial activities in general. In conclusion, TLM exhibited highly selective antimicrobial activities to black-pigmented Bacteroides species and A. actinomycetemcomitans, both of which are implicated in the pathogenesis of human periodontal disease.

Actinobacillus↗
PubMed1990

[Spore-spheroplast transformation of Bacillus megaterium].

A new method for transformation of Bacillus megaterium was developed by modification of Chang and Cohen's method. In our method, spore spheroplasts were used as recipient cells instead of the protoplasts of vegetative cells. Longer incubation (60 min) of spore spheroplasts and plasmid DNA before treatment with polyethylene glycol remarkably increased the efficiency of transformation. The frequency of transformation was about 10(4) per microgram of plasmid DNA. A shot-gun-type cloning of chromosome DNA of B. megaterium ATCC 12872 was available in B. megaterium ATCC 19213 strain by this transformation method.

Bacillus megaterium↗
PubMed1990

Biochemical and immunochemical characterization of Caenorhabditis elegans metallothioneins I and II induced by cadmium.

Metallothioneins in Caenorhabditis elegans (CeMT-I and II) were purified by the combination of gel filtration, ion-exchange chromatography, and high-performance liquid chromatography. Amino acid compositions and amino-terminal sequences of CeMT-I and II were slightly different from those of vertebrate MTs previously reported, although cysteine residue contents were relatively high. Enzyme immunoassay using anti-CeMT-II antibody showed the difference of antigenicity to rat MT-I and II and even to CeMT-I. Immunohistochemical staining revealed the existence of CeMT-II in the intestine and the eggs, suggesting the role of MT in detoxification and homeostasis of heavy metals.

Amino Acid Sequence↗
PubMed1989

Rapid methods for purification of human recombinant interleukin-5 (IL-5) using the anti-murine IL-5 antibody-coupled immunoaffinity column.

A large scale production of human recombinant IL-5 (hIL-5) was performed by way of recombinant DNA technology. In this study, we transfected Chinese hamster ovary cells with pdKCR-hIL-5gene-dhfr plasmid and selected a cell line, with the use of methotrexate, producing large amounts of hIL-5. The recombinant hIL-5 thus obtained induced IgM production of murine B cell leukemia BCL1, and its activity was inhibited by TB13 anti-mouse IL-5 monoclonal antibody. hIL-5 could be purified from the cell-free supernatants of the transfectants with high recoveries by using anti-mouse IL-5 antibody-coupled immunoaffinity column in combination with a gel permeation column chromatography. N terminal amino acid sequence analysis of purified hIL-5 revealed that a single amino-terminal amino acid (isoleucine) is detected and hIL-5 consists of 115 amino acid residues.

Amino Acid Sequence↗
PubMed1989

Membrane IL-1 induces bone resorption in organ culture.

We have studied the role of the membrane-associated form of IL-1 on bone resorption in vitro. Murine macrophages of the P388D1 cell line stimulated with LPS, subsequently fixed with paraformaldehyde, induced the proliferation of C3H/HeJ mouse thymocytes in the presence of a submitogenic concentration of Con A. Membrane IL-1 on P388D1 cells stimulated with LPS induced bone resorption in organ cultures of neonatal BALB/c mouse calvaria. Polyclonal antibodies directed against membrane IL-1 and soluble IL-1 from P388D1, and monospecific rabbit anti-murine rIL-1 alpha serum neutralized the membrane IL-1 activity, as measured by the thymocyte proliferation. In addition, these antibodies suppressed the bone resorption induced by membrane IL-1. The bone resorption induced by membrane IL-1 required direct contact between mouse calvaria and membrane IL-1. Salmon calcitonin strongly suppressed the calcium release from mouse calvaria in the presence of membrane IL-1. Indomethacin partially inhibited the bone resorption induced by membrane IL-1 on P388D1 cells. Moreover, membrane IL-1 on LPS-stimulated BALB/c mouse peritoneal macrophages or LPS-stimulated osteoblastic cells from BALB/c mouse calvaria induced bone resorption in vitro. These results suggest that membrane IL-1 on macrophages and osteoblastic cells may have a significant role in inflammatory bone resorption in vivo.

Animals↗
PubMed1989

Mortality.

Explore the source record for details and available documents.

Antibiotics, Antineoplastic↗
PubMed1989

Purification and characterization of human microsomal dipeptidase.

Human microsomal dipeptidase (MDP, formerly referred to as dehydropeptidase-I or renal dipeptidase) [EC 3.4.13.11] was solubilized from the membrane fraction of kidney by treatment with octyl-beta-D-glucoside and purified by a procedure including ion exchange chromatography and affinity chromatography on cilastatin-immobilized Sepharose. The purified human MDP was found to be homogeneous on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The apparent molecular weight (Mr) was estimated by SDS-polyacrylamide gel electrophoresis under non-reducing conditions to be 130 kDa, comprising a homodimer of two subunits. After treatment with endoglycosidase F, human MDP showed a single band with an apparent Mr of 42 kDa on SDS-polyacrylamide gel electrophoresis. Human MDP was found to bind to Con A-Sepharose and the activity was eluted with methyl-alpha-D-mannopyranoside, suggesting that human MDP is a glycoprotein. We also examined the substrate specificity of human MDP and found that human MDP catalyzed the hydrolysis of S(substituent)-L-cysteinyl-glycine adducts such as L-cystinyl-bis(glycine) and S-N-ethylmaleimide-L-cysteinyl-glycine, as well as the conversion of leukotriene D4 to leukotriene E4. These results suggest that MDP might play an important role in the metabolism of glutathione and leukotriene.

Amino Acids↗
PubMed1989

Role of outer coat in resistance of Bacillus megaterium spore.

The outer coat fraction (OC-Fr) of Bacillus megaterium ATCC 12872 spore was isolated as a resistant residue after alkali extraction, sonic treatment, and pronase digestion of the spore coat preparation, and its backbone structure was determined by chemical analysis to be composed of galactosamine-6-phosphate (GalN-P) polymers with polypeptides and calcium. OC-Fr was not fully solubilized after ordinary acid hydrolysis. OC-Fr was insensitive to all hexosaminidases tested, and moreover, an isolated fragment, a pentamer of GalN-P, was also resistant to lysozyme and hexosaminidases even after N-acetylation, being sensitive to them to some extent after dephosphorylation. Molecular sieving experiments revealed that the outer coat limited the entry of compounds with a molecular weight of more than 2,000. Exchange of the metal on the spore surface also influenced the heat resistance. Spores of OC-Fr-deficient mutants were less resistant but were still much more resistant than the vegetative cells. These results suggest that the outer coat protects the contents of the spore against chemical, physical and enzymatic treatments owing to the chemical structure itself, composed mainly of GalN-P polymers, and the molecular sieving effect.

Bacillus megaterium↗
PubMed1989

Characterization and deposition of the proteins in the outermost layer of Bacillus megaterium spore.

It was proved that three spore coat proteins of 48, 36, and 22 kDa (P48, P36, and P22) were the components of the outermost layer (OL) of Bacillus megaterium ATCC 12872 spore by analysis of the isolated OL. And it was indicated that these proteins were deposited not by disulfide bond, but by ionic and/or hydrophobic bonds on the spore. Among them, P36 and P22 were expected to be located on the very surface of the spore by immunological analysis. In the OL deficient mutant of B. megaterium ATCC 12872, MAE05, whose spore was lacking in these OL proteins and galactosamine-6-phosphate polymer, both P36 and P22 were present in the mother cell cytoplasm and deposited on the forespores, but they disappeared with the lysis of mother cells. An OL protein-releasing factor having proteolytic activity was detected in the culture supernatant at the late sporulating stage of both the wild-type and the mutant strains. But the factor could not act on the proteins of the mature spores and the forespores at t10 (tn indicates n hr after the end of exponential growth) of the wild-type strain. Moreover, P36 and P22 were found in the spores of a revertant of MAE05 which could form galactosamine-6-phosphate polymer, suggesting that this sugar polymer played the role in protecting the OL proteins against the protease-like substance after the deposition.

Bacillus megaterium↗
PubMed1989

Isolation of the saprophytic strain of MC-3 and participation of the cell surface structure in predation.

From a predatory bacterium, MC-3, a mutant strain which lost predation ability was isolated by chance selection. Biological properties of the mutant were the same as the parent except only saprophytic property. Properties of the parent and the mutant strains of MC-3, such as bacteriolytic activity of the culture supernatant, digestion of peptidoglycan of the host bacteria, and growth by utilizing the host cells or their cytoplasmic substances, suggested that cell surface structure of the host cell plays an important role in predation and host specificity.

Bdellovibrio↗
PubMed1989

Inhibitory effects of rabbit antisera on mitogenic activity of Actinobacillus actinomycetemcomitans lipopolysaccharide.

Lipopolysaccharides (LPSs) were isolated from Actinobacillus actinomycetemcomitans strains ATCC 29523 (serotype a), Y4 (b), and NCTC 9710 (c) by the hot phenol-water procedure. Y4 lipid A was obtained by the hydrolysis of Y4 LPS in 1% acetic acid. All the LPS preparations and Y4 lipid A were mitogenic for C3H/HeN mouse spleen cells, but not for C3H/HeJ mouse spleen cells. Immunoglobulin preparations partially purified by ammonium sulfate precipitation at 33% saturation from rabbit antisera against Y4 whole cells inhibited the mitogenic response of C3H/HeN mouse spleen cells to LPSs from all the strains of A. actinomycetemcomitans and Y4 lipid A. Anti-Y4 LPS immunoglobulin preparation inhibited the mitogenic activity of Y4 LPS and Y4 lipid A. Furthermore, anti-Y4 whole cell Fab fragments inhibited the mitogenic activity of both Y4 LPS and Y4 lipid A. These results suggest that antibodies against A. actinomycetemcomitans LPS may modify immune responses of lymphocytes to this organism at periodontal sites.

Actinobacillus↗
PubMed1989

Immunochemical and structural characterization of a serotype-specific polysaccharide antigen from Actinobacillus actinomycetemcomitans Y4 (serotype b).

A serotype-specific polysaccharide antigen of Actinobacillus actinomycetemcomitans Y4 (serotype b) was extracted from whole cells by autoclaving. The extract was purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. The purified polysaccharide antigen formed a single precipitin line with anti-type b serum but not with anti-type a serum and anti-type c serum. The antigen was composed of 43.9% L-rhamnose, 49.1% D-fucose, and a trace amount of fatty acid. Methylation analysis, Smith degradation, and optical rotation data showed that the antigen was a polymer consisting of a disaccharide repeating unit, ----3)-alpha-D-fucopyranosyl-(1----2)-beta-L-rhamnopyranosyl-(1----. In quantitative precipitin inhibition tests, D-fucose and L-rhamnose showed very low inhibition, but the partial hydrolysate of the purified antigen was an effective inhibitor, suggesting that the serotype b specific antiserum recognizes the larger oligosaccharide units.

Actinobacillus↗
PubMed1989

[Evaluation of the anti-ulcer drugs using image analysis technology: effect of aldioxa containing preparation on the experimental gastric ulcer in rats].

Direct measurements under a microscope have been employed to evaluate experimental gastric ulcers, but the following problems have been left unsettled: it takes too much time, and much experience is required to perform accurate, objective measurements. The present study demonstrates the usefulness of image analysis technology for evaluating anti-ulcer drugs. With this newly developed method, the region of gastric mucosal injury can be automatically and/or mechanically chosen on the basis of three different factors: intensity, hue and purity. Consequently, this method can be used to rapidly obtain analytical data such as the number, area and length of gastric ulcers. Effect of NNP, a preparation containing aldioxa, on three different types of experimental ulcer formation (stress-induced, ethanol-induced, and pylorus-ligation) was studied by image analysis technology. In all cases, NNP (2,562 mg/kg, p.o.) almost completely inhibited the formation of rat gastric ulcer. From the finding that image analysis technology is very useful for evaluating anti-ulcer drugs, we conclude that this method will help further the development of anti-ulcer drugs.

Allantoin↗
PubMed1989

Fungal flora in rainwater.

We analyzed rainwater samples collected throughout a year for fungal flora and compared the results to those from atmospheric samples. Differences between the seasonal variation in number of fungi in rainwater and that in number of fungi in the atmosphere were found; that is, there was less of a difference among rainfall samples from different sampling points than among atmospheric samples. In the rainwater samples 29 fungal genera were detected, whereas only 17 were detected in the atmospheric samples. The variations in Cladosporium and Penicillium were the determinants of the total number of fungi in rainwater, whereas in air the variation in Cladosporium alone was the determinant. Sampling of rainwater therefore can be expected to provide information on fungal flora in the troposphere that cannot be obtained by means of air sampling.

Air Microbiology↗
PubMed1989

[Decreased plasma alpha 1-proteinase inhibitor activity in idiopathic nephrotic syndrome].

We measured plasma alpha 1-proteinase inhibitor (alpha 1-PI) levels in patients with idiopathic nephrotic syndrome (INS), chance proteinuria and/or hematuria, and normal controls to examine the roles of proteinase inhibitors in the pathogenesis of renal diseases. Plasma alpha 1-PI concentrations were significantly decreased in patients with INS at relapses and remissions of INS. The alpha 1-PI activities, anti-trypsin and anti-elastase activities, were also decreased in relapses of INS. However, the values revealed no statistically significant difference in remissions of INS. Significant correlations between the PI activities and alpha 2-macroglobulin levels were revealed, which suggested a possible contribution of alpha 2-macroglobulin to the plasma PI activities in INS. From these results we conclude that the decrease in plasma alpha 1-PI activities may be responsible for the reduction of glomerular negative charge, possibly caused by some unknown proteinase(s), and the resultant development of proteinuria.

Adolescent↗
PubMed1988

Inhibition of in vitro angiogenesis by lymphotoxin and interferon-gamma.

The effects of lymphotoxin (LT) and interferon (IFN)-gamma on the capillary formation was examined using an in vitro angiogenesis model system. Both LT and IFN-gamma inhibited the capillary formation in a dose dependent manner. To elucidate the mode of action, effects of the lymphokines on endothelial and myofibroblastic cells were studied. We found that the lymphokines inhibited not only the growth of endothelial cells but also the production of collagen by myofibroblastic cells. These results suggest that the pleiotropic effects of the lymphokines on different types of cells might result in the inhibition of the capillary formation.

Angiogenesis Inducing Agents↗