K Kimura’s research while affiliated with Sapporo Medical University and other places

Asaccharolytic pigmented Porphyromonas strains were isolated from the plaque of dogs with gingivitis and periodontitis. Various species of Porphyromonas, including P. endodontalis, P. gingivalis, P. circumdentaria and unclassified species, were detectable. Canine Porphyromonas were sensitive to Japanese green tea extract (JGTE). We examined the effects of dietary JGTE on periodontal diseases. A special diet was prepared on the basis of the minimum inhibitory concentration (MIC: 0.8 mg/ml) of JGTE to several canine Porphyromonas species. Growth of all Porphyromonas isolates was inhibited at this concentration. After 2 mths, the percentage of canine Porphyromonas significantly decreased in the plaque microbiota. Concurrently with the observed decrease in percentage of these bacteria, gingival inflammation was inhibited. However, no change in the calculus index was recorded during the observation period. Levels of oral malodour varied among the dogs and diet with JGTE was effective in the inhibition of oral malodour. We concluded that JGTE was effective in the inhibition of canine periodontal diseases.

Background: The pathogenicity of Behçet's disease (BD) has been associated with the offending pathogen Streptococcus sanguis. However, it is unclear that the bacterium is a true pathogen. Materials and Methods: Germ-free mice were inoculated with a clinical isolate (strain BD113-20) of S. sanguis. Mice received heat or mechanical stress on their oral tissue before the bacterial infection. Colonization, immune responses against the cell wall and synthetic peptides, and the cytokine profile were examined. Uveitogenicity of the cell wall, lipoteichoic acid (LTA), muramyl dipeptide (MDP), human hsp336-351, S. sanguis-associated peptides, and retina-associated peptides were examined. Results: S. sanguis colonized the oral cavity at 105-8/mL saliva. The level of colonization in mice given heat or mechanical stress was significantly higher than the other groups. These mice showed typical oral ulcers after the bacterial challenge and mild iridocyclitis. Skin lesions were spread whereas genital ulcers were rare in these groups. Significant antibody production to the selected peptides was observed in the experimental mice compared with control animals. Inflammatory cytokines such as IL-2, IL-6, IFN-g, and TNF-a were detected in oral tissue of the mice infected with S. sanguis. Evidence suggests that the association with the cell wall or with LTA can directly affect the degree of inflammation. Conclusions: S. sanguis strain BD113-20 is pathogenic for experimental mice and can be a causative agent for BD. Molecular mimic peptides can be implicated in the pathogenesis of BD. The cell wall of the bacteria shows direct ocular inflammogenicity.

Although the etiology and pathogenesis of Behçet's disease (BD) is poorly understood, streptococcal infectious allergy has long been postulated as one of the triggers for the onset of the disease. Bes-1 gene encoding a streptococcal antigen, which we recently cloned, seems to be homologous to the human intraocular peptide Brn-3b. To investigate the relationship between Bes-1 and BD, polymerase chain reaction (PCR) analyses were performed to detect Bes-1 DNA in samples of lesional tissues from patients with BD and patients with other inflammatory disorders who served as control subjects. Three (one each of clinically complete type, incomplete type, and suspected type) of 11 BD cases and one phlegmone case resulting from streptococcal infection were positive for Bes-1 DNA. PCR in situ hybridization was performed to determine the distribution of Bes-1 DNA in the BD lesional skin samples, and amplification of the Bes-1 sequence was detected in the nuclei of cells in the dermal vessel walls and in infiltrating mononuclear cells in lesions taken from patients with BD. These findings indicate that Bes-1 DNA might be involved in the pathogenesis of BD.

The ability of an anti-TNF-alpha antibody to confer protection against enterohaemorrhagic Escherichia coli (EHEC) O157 was investigated in germfree IQI mice. The use of an antibiotic levofloxacin (LVFX) alone or with the antibody was also studied. Protection included an increase in survival rate. Treatment with the anti-TNF-alpha antibody inhibited the histological signs associated with EHEC infection but did not prevent the colonization of EHEC or production of Shiga toxin (Stx). No clinical signs were observed and EHEC was completely eliminated in the mouse model receiving both anti-TNF-alpha antibody and LVFX. Anti-TNF-alpha antibody suppressed inflammatory cytokine response in the mouse kidney and brain by EHEC infection.

We report that administration of leptospiral lipopolysaccharide (LPS) in mice results in massive surface marker changes in the lymphocytes of the spleen. It appears that many of these changes relate to the large number of cells undergoing apoptosis. It is also shown that tumor necrosis factor-alpha (TNF-alpha) induces similar effects and is produced in large quantities after injection of leptospiral LPS. It is likely that cytokines such as TNF-alpha are involved in apoptosis.

This study describes the levels of interleukin-1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF alpha) and interleukin-6 (IL-6) in the sera and parenchymal organs of various congenic mouse strains infected with Borrelia garinii. A significant elevation of inflammatory cytokine levels was found in the organs of C3H/HeN (H-2k) and B10.BR (H-2k) mice but not in those of BALB/c mice (H-2d). Focally produced cytokines can contribute to antimicrobial defense against these organisms. High levels of IL-1 alpha were observed in the sera of C3H/HeN, B10.BR and B10 (H-2b) mice infected with B. garinii and they were associated with the presence of spirochetes in the skin. Thus, susceptible mice demonstrated a stronger cytokine response than resistant mice. This study presents in vivo evidence that B. garinii infection affects the immunopathogenesis of Lyme disease.

White rabbits in a family, which were clinically diagnosed as moderately or severely diseased with spirochetosis, were bacteriologically and immunologically examined. The specimens from the diseased rabbits, including affected prepuces, scrotum, or skins with an occasional presence of the spirochetes, did not, however, result in growth in six conventional culture media. Serological tests, including quantitative complement fixation test, rapid plasma reagin card test, Treponema pallidum hemagglutination test, and microscopic agglutination test for leptospires using sera from diseased rabbits showed no differences when compared with those of pooled normal rabbit sera. Immunoblot analysis of the polypeptides from three human oral treponemes and three non-oral spirochetes demonstrated that antibodies against several treponemal polypeptides were detected.