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Biomedical subjects

Isao Miyairi

Publications and source records attributed to Isao Miyairi.

6 recordsLinked to original sources
PubMed2006

Different growth rates of Chlamydia trachomatis biovars reflect pathotype.

BACKGROUND: Despite small genomic differences, Chlamydia trachomatis biovars exhibit diverse disease manifestations and different growth rates in vivo and in cell culture models. METHODS: Chlamydial inclusion-forming units were enumerated over time in HeLa cells, to evaluate the length of the developmental cycle for C. trachomatis strains A, B, C, and E/Bour (ocular strains) as well as D, E/UW5/Cx, F, and L2 (genital strains). Prototype strains A, D, and L2 were selected for detailed analysis of reticulate body growth, division, and genomic replication. The impact that changing host cells and that coinfection with different strains has on growth was also assessed. RESULTS: The genital strains completed the developmental cycle in 36-44 h, whereas the ocular strains lagged behind considerably. Differences were the result of a longer lag phase (entry plus differentiation) and generation time for the ocular strains. A prototype ocular strain grew faster in conjunctival cells than in cervical cells. Coinfection with genital (D or L2) and ocular strains expedited recovery of the ocular strain. CONCLUSIONS: Precise temporal evaluation of the chlamydial developmental cycle for selected genital and ocular C. trachomatis biovars provides a means for investigating genomic differences that define chlamydial pathotype.

Chlamydia trachomatis↗
PubMed2006

Chlamydia and programmed cell death.

Discordant views regarding host cell death induction by Chlamydia are likely owing to the different methods used for evaluation of apoptosis. Apoptotic and non-apoptotic death owing to both caspase-dependent and -independent activation of the Bax protein occur late in the productive growth cycle. Evidence also suggests that Chlamydia inhibits apoptosis during productive growth as part of its intracellular survival strategy. This is in part owing to proteolytic degradation of the BH3-only family of pro-apoptotic proteins in the mitochondrial pathway. Chlamydia also inhibits apoptosis during persistent growth or in phagocytes, but induces apoptosis in T cells, which suggests that apoptosis has an immunomodulatory role in chlamydial infections. The contribution of apoptosis in disease pathogenesis remains a focus for future research.

Apoptosis↗
PubMed2006

Group B streptococcal ventriculitis: a report of three cases and literature review.

This report presents three cases of neonatal group B streptococcal ventriculitis and assesses seven others identified by a literature review. In contrast to the well described acute manifestations of group B streptococcal meningitis, disease onset tended to be insidious with four of seven cases presenting over a period of 1 to 6 weeks and six cases presenting with nonspecific signs and symptoms without fever. Persistent protein content elevation and low glucose level in the cerebrospinal fluid was observed, indicating chronic inflammation. All patients developed obstructive hydrocephalus requiring ventriculoperitoneal shunt placement. One child died, and six of nine survivors were left with significant neurologic deficits. Physicians should be aware of this indolent but serious manifestation of group B streptococcal infection.

Acute Disease↗
PubMed2005

Acute necrotizing ulcerative gingivitis and bacteremia caused by Stenotrophomonas maltophilia in an immunocompromised host.

An 8-year-old girl with leukemia developed acute necrotizing ulcerative gingivitis with Stenotrophomonas maltophilia and herpes simplex virus. Progression to bacteremia with pathologic evidence of osteomyelitis occurred despite appropriate antimicrobial therapy. This case highlights the importance of prompt recognition, debridement and appropriate therapy in immunocompromised patients with acute necrotizing ulcerative gingivitis.

Bacteremia↗
PubMed2004

Neonatal invasive group A streptococcal disease: case report and review of the literature.

We present a fatal case of neonatal invasive group A streptococcal disease and review of the literature. Twenty-four cases were early onset disease and were associated with concurrent maternal infection, respiratory distress, pneumonia, toxic shock-like syndrome and serotype M1. Fifteen cases were late onset disease associated with soft tissue infections and meningitis. Maternal carriage was identified as an important factor in neonatal group A streptococcal disease.

Anti-Bacterial Agents↗