Lipopolysaccharide (LPS)-induced Interferon (IFN)-gamma production by decidual mononuclear cells (DMNC) is interleukin (IL)-2 and IL-12 dependent.

PROBLEM: Th1-shifted immune response is believed to be harmful for successful pregnancy because of activation of maternal cytotoxic T lymphocytes and natural killer cells. However, its effects on Toll-like receptor (TLR)-mediated innate immune response are so far unknown and this study has been undertaken to address the issue. METHOD OF STUDY: decidual tissues were obtained from 16 pregnant women undergoing elective termination during the first trimester pregnancy for socioeconomic reasons. Decidual Mononuclear Cells (DMNC) were stimulated with suboptimal doses of IL-2 and IL-12 with/without LPS, considered to be a TLR4 ligand, for 48 hr. Productions of IFN-γ and tumor necrosis factor (TNF)-α in culture supernatant were measured with ELISA. RESULTS: (i) IFN-γ production was induced with LPS alone which was strongly up-regulated in the presence of IL-2 and IL-12. (ii) TNF-α was also induced by LPS but was not affected by the presence of IL-2 and IL-12. CONCLUSION: IL-2 and IL-12 up-regulated the production of IFN-γ in DMNC through increasing their susceptibility to LPS. TNF-α production is independent of such a mechanism.

Effective isolation of bacterioplankton genus Polynucleobacter from freshwater environments grown on photochemically degraded dissolved organic matter.

Effective isolation of freshwater bacterioplankton belonging to genus Polynucleobacter from a shallow eutrophic lake and its tributary was achieved by size-selective filtration with a 0.7-mum pore filter and cultivation on R2A agar medium. Partial 16S rRNA gene analysis showed that over 80% of all the strains were highly similar to the Polynucleobacter cluster. Essential medium components for effective cultivation are pyruvate, yeast extract and peptone, whereas soluble starch and glucose are not necessary. Isolate KF001 (affiliated with Polynucleobacter subcluster D) has a strict requirement for organic acids as carbon sources, and we hypothesize that the Polynucleobacter cluster of bacteria could utilize compounds formed via photochemically dissolved organic matter (DOM) degradation for growth. Because organic acids form from solar radiation of DOM in aquatic environments, carbon sources that are typical products of DOM photochemical degradation were added to the medium. These compounds were readily utilized by KF001 in this study. Finally, we observed the stimulation of strain KF001 activity by photochemical degradation of natural lake water. Our findings suggest a carbon flow of DOM photoproducts to Polynucleobacter in the freshwater microbial loop.

Re-evaluation of the true rate of hepatitis C virus mother-to-child transmission and its novel risk factors based on our two prospective studies.

OBJECTIVE: To re-evaluate the true hepatitis C virus (HCV) mother-to-child transmission (MTCT) rate and its novel risk factors. STUDY DESIGN: A comparative study based on our own two prospective studies done during the two periods, 'early' (1989-1994) and 'recent' (1995-2004). RESULTS: All carrier infants became HCV RNA-positive within 3 months after birth. The MTCT and de-carrier rates were, respectively, higher (14.2%) and lower (16.7%) in the recent period, although liver dysfunction of carrier infants was found very frequently (66.7%) in both groups. MTCT occurred significantly when the maternal viral load, serum alanine aminotransferase (sALT) levels and blood loss at delivery were, respectively, more than 10(5) copies/mL, 110 IU/L, and 500 g. No MTCT was found when elective cesarean section was done. CONCLUSIONS: The true HCV MTCT and de-carrier rates were found to be much higher and lower than those reported previously. The maternal liver dysfunction (sALT >or=110 IU/mL) and blood loss (>or=500 g) at delivery are the next risk factors to maternal viral load (>or=10(5) copies/mL) for MTCT.