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Biomedical subjects

Y Ishihara

Publications and source records attributed to Y Ishihara.

At least 181 records · Page 10Linked to original sources
PubMed1991

Role of interleukin-1 and prostaglandin in in vitro bone resorption induced by Actinobacillus actinomycetemcomitans lipopolysaccharide.

Lipopolysaccharide (Y4 LPS) isolated from Actinobacillus actinomycetemcomitans strain Y4 induced bone resorption in BALB/c mouse calvaria organ culture. The calcium release from LPS-low responsive C3H/HeJ mouse calvaria by Y4 LPS was very low. Indomethacin almost completely inhibited prostaglandin E2 (PGE2) production by Y4 LPS-stimulated BALB/c mouse calvaria, but did not suppress interleukin-1 (IL-1) release from the calvaria, and partially suppressed the bone resorption. Dexamethasone strongly inhibited the PGE2 and IL-1 production by Y4 LPS-stimulated BALB/c mouse calvaria, as well as Y4 LPS-induced bone resorption. Dexamethasone inhibited expression of membrane IL-1 on osteoblastic cells stimulated with Y4 LPS, but indomethacin did not. Furthermore, anti-IL-1 serum partially suppressed the calcium release from Y4 LPS-stimulated BALB/c mouse calvaria. These results suggest that both PGE2 and IL-1 participate in Y4 LPS-induced bone resorption in vitro.

Actinobacillus↗
PubMed1991

Murine macrophage interleukin-1 release by capsularlike serotype-specific polysaccharide antigens of Actinobacillus actinomycetemcomitans.

Serotype-specific polysaccharide antigens (SPAs) were extracted from whole cells of Actinobacillus actinomycetemcomitans ATCC 29523 (serotype a), Y4 (serotype b), and NCTC 9710 (serotype c) by autoclaving and purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. Y4 SPA induced interleukin-1 (IL-1) release by P388D1 murine macrophages. Polymyxin B had virtually no effect on the release of IL-1. Rabbit anti-murine IL-1 serum strongly suppressed the proliferation of C3H/HeJ mouse thymocytes induced with the culture supernatants of Y4 SPA-stimulated P388D1 cells and a submitogenic dose of concanavalin A. Gel filtration of the culture supernatants of Y4 SPA-stimulated macrophages on Sephacryl S-200 showed that an IL-1 peak at a point corresponding to approximately 16.5 kDa was eluted. The ability of SPAs from strains ATCC 29523 and NCTC 9710 to induce the release of IL-1 was lower than that of Y4 SPA. The IL-1-releasing ability of serotype a and c antigens was enhanced by deacetylation of both polysaccharides, suggesting that acetyl groups of these antigens might hinder the interaction between the antigens and macrophages.

Actinobacillus↗
PubMed1991

Central cholinergic agents. I. Potent acetylcholinesterase inhibitors, 2-[omega-[N-alkyl-N-(omega-phenyl-alkyl)amino]alkyl]-1H-isoindole- 1,3(2H)-diones, based on a new hypothesis of the enzyme's active site.

It has been suggested that the active site of acetylcholinesterase contains a hydrophobic binding site (HBS-1), which is closely adjacent to both the anionic and the esteratic sites. In this paper, we assumed that there exists another hydrophobic binding site (HBS-2), some distance removed from the anionic site. On this assumption, a new working hypothesis was proposed for the design of acetylcholinesterase inhibitors. A series of 2-[omega-[N-alkyl-N-(omega-phenyl-alkyl)amino]alkyl]-1H- isoindole-1,3(2H)-diones was designed based on this hypothesis and tested for its inhibitory activities on acetylcholinesterase. Some in this series were revealed to be more potent than physostigmine. Optimum activity was found to be associated with a five carbon chain length separating the benzylamino group from the 1H-isoindole-1,3(2H)-dione (phthalimide) moiety. Quantitative study of substitution effect on the phthalimide moiety revealed that hydrophilic and electron-withdrawing groups enhance the activity.

Acetylcholinesterase↗
PubMed1991

Suckling stimulates the expression of vasoactive intestinal polypeptide gene in rats.

The effect of suckling on vasoactive intestinal polypeptide (VIP) gene expression in the hypothalami was studied during the postpartum period in rats. Female rats were divided into two groups immediately after delivery. In one group, a mother was housed with 8 pups, and in the other, without any pups. The former group was named S(+) and the latter S(-). On days 0, 3, 6, 9 and 12 after delivery, the mothers were killed by decapitation. Hypothalamic VIP mRNA was measured by RNA dot hybridization. Although the VIP mRNA level showed no significant change after delivery in the S(-) group, VIP mRNA in the S(+) group on days 6, 9 and 12 increased to 1.6, 3.5 and 2.1 times higher than the level observed on day 0, respectively. These results suggest that suckling induces the synthesis of VIP after 6 postpartum days.

Actins↗
PubMed1991

Melanostatin, a new melanin synthesis inhibitor. Production, isolation, chemical properties, structure and biological activity.

Melanostatin, a new antibiotic with melanin synthesis inhibitor activity, was isolated from the fermentation broth of Streptomyces clavifer No. N924-2. Its structure was determined by spectral analysis and degradation experiments. Melanostatin strongly inhibited melanin formation in Streptomyces bikiniensis NRRL B-1049 and B16 melanoma cells.

Chromatography, Thin Layer↗
PubMed1991

[Sulfuric acid submicron aerosols induce morphological changes in the central airways in the guinea pig].

We examined the airway injury of the guinea pig exposed to sulfuric acid submicron aerosols (1 mg/m3). The animals were exposed to filtered air (sham control) or to submicrometer-sized sulfuric acid aerosols for 4 hr/day, 6 days/week, with sacrifices after 4 hours, 3 days, 1, 2, and 4 weeks of acid exposure. Light and electron microscopic examinations revealed that epithelial injury such as disappearance of cilia in the central airways was observed and the severity of the injury increased with exposure duration. This experimental study shows that submicrometer particles of sulfuric acid induces significant alterations in the central airways and may be involved in the incidence of asthma attack.

Aerosols↗
PubMed1990

"Autoregulation" of human neutrophil activation in vitro: regulation of phorbol myristate acetate-induced neutrophil activation by cell density.

Phorbol myristate acetate (PMA, 10(-7) M) activation of adherent neutrophils (PMNs) led to a markedly attenuated release of superoxide anion (O2-) per cell when PMNs were activated at high density (2.85 fmol O2-/PMN at 2 million in 0.1 ml) in comparison with cells activated at low cell density (12.0 fmol O2-/PMN at 250,000 in 0.1 ml). This "autoregulatory" phenomenon was not due to a defect in the superoxide anion assay employed, to a differential adherence of neutrophils at high vs. low density, or to substrate (cytochrome c) or cell stimulus (PMA) limitation. It was associated with an inhibition of apparent NADPH oxidase activity and a leftward shift (toward a lower level of activation) in the activation profile of PMNs (as determined by FACS analysis using PMNs preloaded with 2'7'-dichlorofluorescin diacetate in which H2O2 production results in the production of the fluorescent product 2'7'-dichlorofluorescein intracellularly). Other aspects of the neutrophil activation response including arachidonic acid mobilization, phospholipid metabolism, and perhaps phosphatidylinositol turnover were also attenuated when PMNs were activated at high cell density. Studies with cells in solution, cells treated with cycloheximide, and cells treated with 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid suggest that PMN contact with a surface, neutrophil protein synthesis, and an increased surface expression of the heterodimer CD11b/CD18 on PMNs all were not required for autoregulation. Finally, morphometric and morphologic examination of PMNs activated at low vs. high density revealed histologic and structural correlates associated with the attenuated PMN activation response of cells triggered at high cell density. We conclude that multiple structural and functional aspects of the PMN activation response are modulated by cell density and suggest that this property is important both in the physiologic control of neutrophil activation and in the design of in vitro assays of the neutrophil activation response.

Arachidonic Acid↗
PubMed1990

Calcium is required for PMA induced superoxide release from human neutrophils.

Experiments were designed to reexamine the relationship between extracellular calcium and superoxide generation in phorbol myristate acetate (PMA) stimulated neutrophils exploiting a newly adapted method to measure superoxide anion (O2-) generation from adherent cells stimulated at high and low cell density. Human neutrophils were plated in microtiter wells in cell densities of either 0.2 or 2.0 million cells/well. Superoxide release was measured sequentially over 60 min by reduction of ferricytochrome c. Cells were maintained in 1 mM Ca++ or 0 mM Ca++ Hanks' buffer for 60 min prior to activation as well as during measurement of O2-. In 1 mM Ca++, 2.0 million adherent neutrophils released 10.7 +/- 1.2 nmol O2- in 20 min (n = 4). O2- release was not significantly different for high density cells incubated and stimulated in 0 mM Ca++. In the presence of 1 mM Ca++, 0.2 million adherent neutrophils released 6.3 +/- 0.5 nmols O2- in 20 min. With cells stimulated at low density, PMA stimulated O2- release was significantly decreased (3.0 +/- 0.6 nmol O2- in 20 min) as was the initial rate of secretion of O2- in the absence of extracellular calcium. Basal release of superoxide was also greater in the presence of 1 mM Ca++ (0.96 nmol/20 min) compared to basal release in 0 mM Ca++ (0.22 nmol/20 min). Additional experiments with 0.2 million cells/well showed that extracellular Ca++ was required during stimulation with PMA and that prior incubation of cells for up to 60 min in 0 mM Ca++ had no effect on O2- release measured in the presence of calcium. Furthermore, PMA stimulated O2- was independent of verapamil (10(-5)-10(-7) M), suggesting that voltage-dependent calcium channels do not participate in this response. The planar areas for unstimulated neutrophils in 0 mM Ca++ increased after addition of PMA. Unstimulated cells in 1 mM Ca++ tended to be larger and planar areas did not increase after PMA. These studies demonstrate that PMA stimulated O2- secretion is dependent on extracellular calcium particularly when adherent neutrophils are stimulated at low cell density. Furthermore, extracellular calcium at a concentration of 1 mM primes neutrophils by increasing basal secretion of O2- and increasing superoxide release after a maximum stimulating dose of PMA.

Calcium↗
PubMed1990

Massive pancreatic pleural effusion: pathogenesis of pancreatic duct disruption.

Massive pancreatic pleural effusion is believed to be caused by pancreatic duct disruption. To elucidate the cause of the duct disruption, pancreas specimens resected from three cases of massive pancreatic pleural effusion were investigated histopathologically. There was no evidence of either chronic or acute pancreatitis except focal fibrosis along a single dilated duct in the resected pancreas. From our study, the pathogenesis of pancreatic duct disruption is suggested as follows: (a) alcohol ingestion can induce focal acute inflammation on a single branch of the duct system and elicit protein plug formation; and (b) focal stenotic change occurs on this branch at a point near the main pancreatic duct, and transient obstruction can occur by means of the protein plugs. The "upstream" extent of this branch will then dilate until it ruptures. However, on the frequency of this atypical pancreatitis, we have no clues to mention.

Acute Disease↗
PubMed1990

Monoclonal antibody-coated latex agglutination assay for identification of Actinobacillus actinomycetemcomitans.

Three monoclonal antibodies (MAbs) to lipopolysaccharide of Actinobacillus actinomycetemcomitans strain Y4 (serotype b) and eight MAbs to a serotype b-specific polysaccharide antigen of strain Y4 were obtained. Latex particles sensitized with an MAb to the Y4 lipopolysaccharide produced a positive agglutination with whole cells of all three serotypes of A. actinomycetemcomitans, but not with Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzae, Porphyromonas (Bacteroides) gingivalis, "Bacteroides" intermedius, Fusobacterium nucleatum and Escherichia coli. On the other hand, latex particles sensitized with an MAb to the serotype b-specific polysaccharide antigen agglutinated with whole cells of serotype b A. actinomycetemcomitans and P. gingivalis, but not with heated and trypsinized cells of P. gingivalis. The simple and rapid latex agglutination assay using MAbs may be useful for the identification of A. actinomycetemcomitans.

Actinobacillus↗
PubMed1990

Fecal IgA antibody responses after oral poliovirus vaccination in infants and elder children.

We investigated fecal IgA antibody responses after oral polyvalent poliovirus vaccination. Infants were given vaccines twice with an interval of 6 weeks. Specific IgA antibodies in the feces were determined by enzyme-linked immunosorbent assay, and viruses were isolated in tissue cultures. We found that, after the first vaccination, antibody responses seemed to be elicited only against the serotypes of isolated viruses. After the second vaccination, however, antibodies were detected to all three serotypes with higher titers, suggesting that the first vaccination induced the immunologic memory. The IgA antibodies had virus-neutralizing activity, and existed in the feces as both intact 11S and fragmented 4S molecules. Next, children were given the third vaccination 3 or 9 years later. Fecal IgA antibody responses were found to be poorer in elder children, while they responded with high serum neutralization titers. The secretory IgA memory seemed to last much shorter the serum IgG memory.

Adolescent↗
PubMed1990

Enzyme-linked immunosorbent assay employing monoclonal antibodies for direct identification of enteric adenoviruses (Ad40,41) in feces.

For detection and identification of enteric adenovirus (Ad) types 40 and 41 in stool specimens, enzyme-linked immunosorbent assay (ELISA) was developed with the use of three monoclonal antibodies: Ad group-specific, Ad40 type-specific, and Ad41 type-specific antibodies. Of 860 fecal samples from patients with acute gastroenteritis, 44 strains of Ad were isolated using Graham 293 cell cultures. Of these isolates, 20 were typed as Ad40, 18 were Ad41, and 6 were other Ads by neutralization tests with cell cultures. Results of the ELISA tests on these 860 fecal samples resulted in good agreement to those with the cell culture method. The ELISA tests using Ad type-specific monoclonal antibodies proved to be a specific and rapid technique for laboratory diagnosis of acute gastroenteritis caused by enteric Ads.

Acute Disease↗
PubMed1990

[Effects of DEAE-dextran, centrifugation, cycloheximide and their combination on infection and growth of Chlamydia psittaci bird isolates].

In order to establish a stable and uniform cultural method in a cell line HaLa 229, we studied the effect of DEAE-dextran, centrifugation, cycloheximide and their combination on infectivity and progeny yields of Chlamydia psittaci isolated mainly from birds. Of 11 strains (10 avian and one human origin Ito strain), 9 showed maximal inclusion formation when host cells were treated with a combination of dextran and cycloheximide. Of the other two strains, one showed maximum inclusion formation with dextran alone and any treatments did not enhance the inclusion formation in another strain. Maximal yields of progeny at 48 hours after infection was observed in 5 (4 avian and Ito) strains when host cells were treated with a combination of dextran and cycloheximide. One avian strain showed maximal yields with a triple treatment; dextran and cycloheximide combined with centrifugation. At 72 hours after infection, three avian and Ito strains showed maximal yields with a double treatment (dextran and cycloheximide) and other two avian strains showed that with a triple treatment (double treatment added with centrifugation). The results suggest that in a cell culture HeLa 229, the treatment with dextran and cycloheximide may provide an efficient isolation and growth pattern for most strains originated from birds.

Animals↗
PubMed1990

Synthesis of isoindolo[2,1-a]quinoline derivatives and their effects on N2-induced hypoxia.

A variety of isoindolo[2,1-a]quinoline derivatives as well as the following related heterocycles have been prepared: 11b,12-dihydro-5H-isoindolo[2,1-b][2]benzazepine-7,13-dione (8a), 7,8,14,14a-tetrahydroisoindolo[2,1-c][3]benzazocine-5, 13-dione (8b), 6a,7-dihydroisoquinolino[2,3-a]quinoline-5,12-dione (12), 2,3,3a-4-tetrahydropyrrolo[1,2-a]quinoline-1,5-dione (14), and pyrido[2',3':3,4]pyrrolo[1,2-a]quinoline-5,11(5H)-dione (17). The key synthetic step involves an intramolecular Friedel-Crafts reaction of acid chlorides such as isoindole-1-acetyl chlorides (4), the acids (3) of which were prepared starting with 2-arylisoindole-1,3(2H)-diones (2-arylphthalimides) (1). The protective effects of isoindolo[2,1-a]quinoline derivatives (19 and 20) against N2-induced hypoxia were examined. Among them, 6-(diethylaminomethyl)isoindolo[2,1-a]quinoline-5,11(5H)-dio ne (19b) showed the most potency.

Animals↗
PubMed1990

[Stress analysis of bridge abutment teeth with cemented dowels].

Stress analysis of bridge abutment teeth having cemented dowels was conducted using a two-dimensional finite element method. The results obtained are as follows: 1. In fixed-fixed bridges, compressive stress was found concentrated within the dowel, on the mesial side of the dowel apex, and in the distocervical part of the crown. 2. In cantilever bridges, tensile stress was found concentrated in the disto-occlusal and mesiocervical parts of the crown, and along the mesial sides of the root and the dowel. Compressive stress was concentrated in the distocervical part of the crown, along the distal sides of the root and dowel, and on the mesial side of the dowel apex. 3. In comparison with fixed-fixed bridges, stresses were significantly greater in cantilever bridges in the abutment teeth, the dowel, and crown margins. 4. In both fixed and cantilever bridges, stresses increased in relation to the length of the span. The rate of increase was less, however, in fixed-fixed than cantilever bridges.

Dental Abutments↗
PubMed1990

[Clinical study of tumor markers in prostatic cancer].

We measured prostatic acid phosphatase (PAP), gamma-seminoprotein (gamma-Sm) and prostatic specific antigen (PSA) levels simultaneously in the serum of 52 patients with untreated prostatic cancer and 44 patients with benign prostatic hypertrophy to assess the clinical usefulness of these tumor markers. PAP and PSA were measured by radioimmunoassay and gamma-Sm by enzyme immunoassay. The positive rates of PAP, gamma-Sm and PSA in patients with prostatic cancer were 50.0, 61.5 and 69.2%, respectively, and those in patients with benign prostatic hypertrophy were 11.4, 13.6 and 13.6%, respectively. In patients with early stage prostatic cancer (stage A and B), the positive rates of PAP, gamma-Sm and PSA were 20.8, 41.7 and 54.2%. The efficiency of PSA was the highest among the three markers. The positive rate of the combination assay of PAP and PSA, that of gamma-Sm and PSA and that of PAP, gamma-Sm and PSA were slightly higher than that of the PSA assay alone. However, the efficiency of the PSA assay alone was higher than that of any combination. No significant correlation was found between histopathological grade and the level of each tumor marker. A significant correlation was found between PAP and gamma-Sm (r = 0.68, P less than 0.001), and between PAP and PSA (r = 0.61, P less than 0.001), but there was no correlation between gamma-Sm and PSA. These results suggest that PSA is the most useful marker and the combination assay of multiple markers is not so advantageous, at least for screening of prostatic cancer.

Acid Phosphatase↗
PubMed1990

[Microbiological and chemical analyses of indoor swimming pools and virucidal effect of chlorine in these waters].

Virological and bacteriological examinations and chemical analysis were made of 24 water samples from 6 public indoor swimming pools in Aichi Prefecture. In 3 of these swimming pools, sodium hypochlorite was used as a disinfectant and in the remainder trichloroisocyanurates. All samples were negative for adenovirus per 20 liters. Coliform group was detected in one sample with 26.7 mg/l cyanuric acid. Total plate counts ranged from 0 to 1 per ml in the swimming pools treated with sodium hypochlorite and 0 to 51 in those with trichloroisocyanurates. Turbidity, pH and potassium permanganate concentrations in the samples were within allowable limits. Seven of 24 samples did not meet the recommended value of 0.4 mg/l for free chlorine residuals. Ammonium nitrogen was detected in one pool water with trichloroisocyanurates. In 11 of 12 water samples of swimming pools using sodium hypochlorite, poliovirus 1 (2 x 10(4) PFU/0.2 ml) was inactivated within 1 min under the condition of 1.0 mg/l free available chlorine and 25 degrees C. In 11 of 12 water samples of 3 swimming pools using trichloroisocyanurates, poliovirus type 1 survived after 2 min contact while in 5 samples poliovirus type 1 survived after 5 min contact. This shows that the risk of viral infection is greater in swimming pool water treated with chlorinated isocyanurics than that with sodium hypochlorite. The operator of the swimming pool should pay special attention to the control of water quality and free residual chlorine value.

Adenoviridae↗