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Biomedical subjects

E Isogai

Publications and source records attributed to E Isogai.

At least 127 records · Page 7Linked to original sources
PubMed1990

Biological effects of leptospiral lipopolysaccharide to mouse B, T and NK cells.

Leptospiral lipopolysaccharides (LPSs) extracted from Leptospira interrogans serovars copenhageni and hebdomadis were tested for the biological effect to mouse B, T and NK cells. Each leptospiral LPS was a potent mitogen for spleen B cells. Activation of the cells was also expressed by polyclonal B cell activation. In contrast, mitogenicity for T cells, induction of interleukin-2 (IL-2) secretion in T cells and increase of tumor-killing activity and chemiluminescence in NK cells were not observed after stimulation with leptospiral LPS. After intravenous injection of leptospiral LPS in mice, the spleen and lymphnodes were examined by histocytochemical technique. Increase of Ig-bearing lymphocytes was recognized while decrease of T cells was observed in the lymphoid organs. Mitogenic response to PHA, Con A and PWM decreased with relation to the T cell depletion. In conclusion, it is apparent that leptospiral LPS possess marked immunological potencies on B cells but not T and NK cells. The biological effects of leptospiral LPS were common ones as LPS but the level was considered to be different from classical LPS such as Escherichia coli LPS.

Animals↗
PubMed1989

Effects of leptospiral lipopolysaccharide on rabbit platelets.

Leptospiral lipopolysaccharides (LPSs) extracted from Leptospira interrogans serovar copenhageni virulent strain Shibaura, serovar canicola virulent strain Moulton, and serovar hebdomadis strain Hebdomadis, were tested for their ability to induce platelet aggregation and/or lysis in rabbit platelet-rich plasma (PRP). All showed positive reactions with a release of adenosine triphosphate (ATP) and serotonin. The values, however, were different from each other. The ability of leptospiral LPS extracted from serovar copenhageni virulent strain Shibaura (I-LPS) to induce platelet aggregation was the highest of all. After treatment of I-LPS, the platelets developed a ruffled surface with appearance of pseudopodia as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). I-LPS also showed cytotoxicity for the platelets. Degenerative or lytic changes were recognized in 44.5% of the platelets which were observed 60 min after I-LPS treatment.

Adenosine Triphosphate↗
PubMed1989

Chemiluminescence and phagocytic responses of rat polymorphonuclear neutrophils to leptospires.

The interaction of leptospires with polymorphonuclear neutrophils (PMN) was examined by the luminol-dependent chemiluminescence (CL) test. Whole blood CL changed in relation to the stage of leptospiral infection both in susceptible (SUS) and resistant (RES) rats. The intensity of CL grew with an increasing number of leptospires in the blood. CL responses were observed in isolated PMN upon exposure to living leptospires. In contrast, the same bacteria, having been inactivated by formalin, did not stimulate PMN. A variation was found in the CL response by different living strains of Leptospira. The CL intensity was arranged as follows: L. illini greater than L. biflexa greater than L. interrogans avirulent strains greater than L. interrogans virulent strains. The CL response was markedly enhanced by an opsonization of leptospires. Specific opsonization was shown to increase the rate of phagocytosis of leptospires with relation to the CL response.

Animals↗
PubMed1989

Biological effects of lipopolysaccharide from Achromobacter stenohalis on lymphocytes and macrophages.

The immunopotentiating activities of lipopolysaccharide from Achromobacter stenohalis (A-LPS) were examined. A-LPS was structurally atypical and gave no endotoxin shock in A-LPS-inoculated mice. Analysis in vitro showed that A-LPS was a potent activator of both macrophages and B-lymphocytes. After macrophage stimulation with A-LPS, interleukin-1 (IL-1) secretion, interferon (IFN) production and chemiluminescence (CL) response were induced. A-LPS was a potent mitogen for spleen lymphocytes. However, induction of interleukin-2 (IL-2) secretion in T lymphocytes was not observed. These activities of A-LPS were similar to or higher than that of enterobacterial LPS.

Alcaligenes↗
PubMed1989

Oral flora of mongrel and beagle dogs with periodontal disease.

The plaque flora was studied in adult mongrel and beagle dogs with periodontal disease. Gingival plaque from maxillary premolars was removed and cultured on various growth media. The flora in all dogs was composed of mostly anaerobic gram negative rods. Bacteroides asaccharolyticus was found in the highest proportion of plaque samples from mongrel dogs, and decomposed hydrogen peroxide suggesting catalase activity. Fusobacterium nucleatum was found in higher proportion in the plaque of beagle dogs as compared to B. asaccharolyticus. With the increasing numbers of obligative anaerobic gram negative organisms such as B. asaccharolyticus, the proportions of Streptococcus, Enterococcus and Staphylococcus decreased in the dogs with periodontal disease. The salivary flora was different from the plaque flora of the dogs with periodontal disease. It was constant regardless with the disease. The salivary flora of beagle dogs with the healthy gingiva was different from that of mongrel dogs. Enterococcus, Lactobacillus, Eubacterium and black-pigmented Bacteroides (BPB, mainly B. asaccharolyticus) were higher proportion in the flora of beagle dogs as compared to mongrel dogs, while Fusobacterium, Enterobacteriaceae, yeast and molds were lower in the flora. The results reveal that B. asaccharolyticus and F. nucleatum are common pathogens and uniquely contribute to the development of gingival inflammation in dog.

Animals↗
PubMed1989

Epidemiological study on periodontal diseases and some other dental disorders in dogs.

The prevalence of dental disorders in dogs was studied by applying index systems for human with some modifications. A total of 251 mongrel dogs including 143 stray dogs kept in the Animal Protection Offices in Tokyo and Hokkaido and 108 pet dogs visiting veterinary clinicians in Chiba Prefecture and Hokkaido were used. Periodontitis was prevalent among these dogs regardless of their sources and its incidence was increased with age. The lesion was more severe and more frequent in the premolar and molar regions than in the maxillary and mandibular incisor regions. Missing of teeth was observed at a high and increasing incidence with age. The tooth most commonly lost was the first premolar, followed by the other premolars and molars, where severe periodontitis was frequently found. Calculus was seen on many teeth, and aging agravated its prevalence and severity. Dental caries was observed in stray dogs, but neither to a serious degree nor at a significant level. These findings emphasize the necessity of dental hygiene, proper dental care and continuous periodical survey for dogs.

Age Factors↗
PubMed1989

Escherichia coli associated endotoxemia in dogs with parvovirus infection.

Escherichia coli bacteremia and endotoxemia were observed in 3 adult mongrel dogs which had been prediagnosed as canine parvoviral disease. The endotoxin level was 46.5 pg/ml in the plasma of clinical cases, while 2.3 pg/ml in healthy controls. The microflora of the feces was confused in the clinical cases. The percentage of E. coli was major in the feces. Serologically similar strains were isolated from the blood. These strains did not produce enterotoxins such as heat-stable enterotoxin (ST) and heat-labile enterotoxin (LT). Histopathologically, the lesions in the small intestine consisted of epithelial degeneration and necrosis. Viral inclusion bodies were frequently observed in the epithelial cells. Disseminated intravascular coagulation was observed in various tissues including the liver and small intestinal submucosa. After experimental infection with CPV, all dogs showed various clinical signs. CPV was positive in the feces. Endotoxin level in the plasma gradually increased and high level continued for long period from 10 to 30 days. Mean maximum level of endotoxin in the experimental dogs was 73.6 pg/ml. These results indicate that intestinal flora plays a important role in the pathogenesis of CPV infection and that endotoxin is one of the factors which predispose to severe disease after the infection.

Animals↗
PubMed1988

Specific inhibition of adherence of an oral strain of Bacteroides gingivalis 381 to epithelial cells by monoclonal antibodies against the bacterial fimbriae.

Monoclonal antibodies against purified fimbriae from this organism blocked its adherence to buccal epithelial cells. Three clones of monoclonal antibodies against these fimbriae were selected for use. The isotype of the three was IgG1 kappa chain. The antibodies reacted with fimbriae or their partially dissociated oligomers, but not with their constituent monomers (43 K protein, fimbrilin) or with other B. gingivalis 381 components, in an enzyme-linked immunosorbent assay or by immuno-blotting. The antibodies agglutinated only B. gingivalis 381 cells and no other species of Bacteroides. The purified immunoglobulin G (IgG) antibodies inhibited bacterial adherence to the human buccal epithelial cells, but had no effect on bacterial haemagglutination to various animal and human erythrocytes. The papain-cleaved Fab fragment, which did not allow cell to cell cross-linking, also inhibited adherence of B. gingivalis 381 but did not interfere with haemagglutination. Thus the fimbriae of B. gingivalis 381 may be responsible for adherence to epithelial cells, which supports the notion that a different type of fimbria or a lectin-like protein may be acting as haemagglutinin in this bacterium.

Antibodies, Monoclonal↗
PubMed1988

Histological changes and some in vitro biological activities induced by lipopolysaccharide from Bacteroides gingivalis.

The biological activities of lipopolysaccharide from Bacteroides gingivalis 381 (B-LPS) were examined in vivo and in vitro. Intra-oral mucosal injection of B-LPS induced an acute inflammation at the injection site. Intravenous injection of B-LPS induced necrotic lesions with many thrombi in the liver and lymphocytic reduction in the spleen. By immunohistochemical examination, B-LPS was detected in macrophages in the liver, spleen and lymph nodes. In vitro analysis showed that B-LPS was a potent activator of both neutrophils and macrophages in luminol-dependent response and IL-1 secretion from macrophages and was mitogenic to the spleen cells not only from BALB/c mice but also from LPS-non-responder C3H/HeJ mice. Interferon production from human peripheral mononuclear leucocytes was induced, in vitro, by stimulation with B-LPS but not with the other enterobacterial LPS. These findings clarified the various biological activities of B-LPS affecting various cells and tissues, especially neutrophils, macrophages and lymphocytes. The potent inflammability of B-LPS shown in the present study indicates that it is one of the effective agents to induce periodontitis.

Animals↗
PubMed1986

Biological activities of leptospiral lipopolysaccharide.

Lipopolysaccharide extracted with phenol-water from Leptospira interrogans serovar copenhageni strain Shibaura (L-LPS) showed various biological activities. In lethality for mice, L-LPS was active (LD 50, 3.4 mg/mouse) but about 12 times less potent than Escherichia coli LPS (E-LPS) per weight basis. L-LPS had pyrogenicity for rabbits, and the fever curves showed no evidence of the classical biphasic fever produced by E-LPS. In the bone marrow of mice, L-LPS caused hemorrhages and necrosis but less severe than those caused by E-LPS. Histopathologically, fresh hemorrhages were found in the intestine, spleen, lung and the other organs at 24 h after inoculation of L-LPS. Necrosis was also found in these organs and was particularly severe in mice inoculated with more than 2 mgL-LPS. Liver necrosis was found at 7th day after inoculation of L-LPS but not after inoculation of E-LPS. L-LPS had adjuvant activity just like E-LPS. L-LPS enhanced non-specific resistance to Salmonella infection and activated mouse peritoneal macrophages to kill these organisms. L-LPS was positive in limulus test just like E-LPS. These results demonstrated similarities of L-LPS and E-LPS. Some toxic effects of L-LPS were less than those of E-LPS, but some effects of L-LPS were more than those of E-LPS. L-LPS was antigenically active and the specificity was serogroup-associated. L-LPS was composed of carbohydrate (54%), lipid (12%), protein (5%). Arabinose, xylose and rhamnose were major sugars as detected by gas chromatography. 2-keto-deoxyoctanate (KDO) was not detectable.

Animals↗
PubMed1986

Phagocytosis as a defense mechanism against infection with leptospiras.

The role of macrophages in host defense was studied in vivo and in vitro. The intravenous administration of silica, an agent reported to selectively inactivate macrophages, increased the sensitivity to leptospiral infection and inhibited bacterial clearance. Active immunization with killed organisms or with leptospiral lipopolysaccharide (L-LPS), and passive immunization with a monoclonal antibody showed powerful protective effects against infection in mice. The effect of immunization decreased in silica-treated mice. These findings were supported by electron microscopic examination and observation of killing by macrophages in vitro.

Animals↗
PubMed1986

Decreased lipopolysaccharide content and enhanced susceptibility of leptospiras to serum leptospiricidal action and phagocytosis after treatment with diphenylamine.

Growth of leptospiras in the presence of diphenylamine (DPA) caused a decrease in the content of leptospiral lipopolysaccharide (LPS). In association with this decrease of LPS, leptospiras became susceptible to anti-leptospiral action of normal rabbit serum (NRS), leptospiricidal action of antibody and complement, and killing by phagocytes. DPA-treated leptospiras were eliminated rapidly from the blood of infected mice and could not grow in the animals.

Aniline Compounds↗