Biomedical subjects

Y Kiyokawa

Publications and source records attributed to Y Kiyokawa.

6 recordsLinked to original sources

PubMed2002

Changes in the proportion of T helper 1 and T helper 2 cells in cord blood after premature rupture of membranes.

This study investigated changes in the proportion of T helper (Th)1 and Th2 cells in cord blood after premature rupture of membranes (PROM), and evaluate the effects of PROM on the intrauterine fetal immune status. The proportion of CD3-positive T cells secreting interferon (IFN)-gamma as an index of Th1 cells, and interleukin (IL)-4 as an index of Th2 cells in cord blood of 12 newborns with and without PROM, were analyzed by flow cytometry. In cord blood of newborns with PROM, the proportion of IFN-gamma secreting cells significantly increased, and the proportion of IL-4 secreting cells was rather high but not significantly higher than that of newborns without PROM. These changes eventually caused a shift in the Th1/Th2 ratio to Th1 dominance in PROM. There was no significant correlation between the proportion of IFN-gamma secreting cells and the duration of PROM before the onset of labor. These results suggest that the increase in the proportion of IFN-gamma secreting cells after PROM, which eventually cause the Th1/Th2 ratios to show the Th1 predominance, may reflect in part intrauterine fetal immune responses to PROM.

Adult↗

PubMed2002

Serum adenosine deaminase activity and its isoenzyme pattern in women with normal pregnancies.

Adenosine deaminase (ADA) is a purine enzyme which is essential for the proliferation, maturation and function of lymphoid cells, and congenital deficiency of this enzyme is associated with severe combined immunodeficiency disease. The activity of ADA has changed in diseases characterized by the alteration of cell-mediated immunity such as rheumatoid arthritis, systemic lupus erythematosus and tuberculosis, so ADA has been considered as a nonspecific marker of cell-mediated immunity. In this study we examined changes in serum total ADA activity and the patterns of two ADA isoenzymes, ADA1 and ADA2 in normal pregnant women, and evaluated the possible role of the alteration of cell-mediated immunity during normal pregnancy as causes of changes in ADA activity. We measured serum activities of total ADA, ADA1 and ADA2 in normal pregnant women in the third trimester (n=24) and age-matched healthy nonpregnant women (n=24). Peripheral blood lymphocytes and monocytes were also measured. In normal pregnant women, serum total ADA activity averaged 10.5 +/- 0.5 U/L, which was significantly lower than in nonpregnant women (14.0 +/- 0.5 U/L ) (p<0.05), and mean serum ADA2 activity also significantly reduced that of nonpregnant women (p<0.05). There was no significant difference in ADA1 activity in normal pregnant and nonpregnant women. The decrease in total ADA activity was accompanied by the decrease in lymphocyte count. These results suggest that reduced serum total ADA activity reflects decrease in ADA2 activity, and which may be in part associated with depressed cell-mediated immunity during normal pregnancy.

Adenosine Deaminase↗

PubMed2001

Plasma adenosine levels and P-selectin expression on platelets in preeclampsia.

OBJECTIVE: To measure the correlation of plasma adenosine levels with platelet activation in women with preeclampsia. METHODS: Plasma adenosine concentration and expression of P-selectin, a marker for platelet activation, were measured in 18 normal pregnant women and 18 preeclamptic women. The effect of 8-sulfophenyltheophylline, an adenosine receptor blocker, on expression of P-selectin on platelets also was measured. RESULTS: Plasma adenosine level averaged 0.77 +/- 0.11 microM (standard error of the mean [SEM]) in women with preeclampsia, significantly higher than the mean level of 0.47 +/- 0.08 microM in women with normal pregnancies (P <.05). Expression of P-selectin on platelets averaged 7.8 +/- 1.2% in women with preeclampsia, also significantly higher than the mean level of 4.7 +/- 0.7% in normal pregnancy (P <.05). Adenosine receptor blockade significantly increased expression of P-selectin on platelets in women with preeclampsia by 26% (P <.05), which was significantly higher than the 13% increase of activation in those with normal pregnancies (P <.05). CONCLUSION: Adenosine is an established platelet activation suppressor. Increased plasma levels of adenosine in preeclampsia might partially compensate and tend to prevent further excessive platelet activation in women with preeclampsia.

Adenosine↗

PubMed2000

Purification and characterization of isoamyl acetate-hydrolyzing esterase encoded by the IAH1 gene of Saccharomyces cerevisiae from a recombinant Escherichia coli.

The IAH1 gene of Saccharomyces cerevisiae encodes an esterase that preferentially acts on isoamyl acetate; however, the enzyme has not yet been completely purified from the yeast S. cerevisiae. We constructed the IAH1 gene expression system in Escherichia coli, and purified the IAH1 gene product (Iah1p). The amount of Iah1p produced by recombinant E. coli was more than 40% of total cellular proteins. The molecular size of Iah1p was 28 kDa by SDS-polyacrylamide gel electrophoresis. Judging from the molecular weight estimation by gel filtration of purified Iah1p, the enzyme was thought to be a homodimer. The Km values for isoamyl acetate and isobutyl acetate were 40.3 mM and 15.3 mM, respectively. The enzyme activity was inhibited by Hg2+, p-chloromercuribenzoate, and diisopropylfluorophosphate.

Carboxylic Ester Hydrolases↗

PubMed2000

Changes in plasma adenosine concentrations during normal pregnancy.

The aim of this study was to measure changes in plasma adenosine concentration [ADO] during a normal pregnancy and to evaluate the possible role of platelets and red blood cells (RBC) as causes of changes in plasma [ADO]. We measured the plasma [ADO] in normal pregnant women (n = 11) during the first, second and third trimesters. The mean plasma [ADO] in the third trimester was 0.41 +/- 0.08 microM (means +/- SEM), significantly higher than in the first and second trimesters (p < 0.05). In pregnant women, platelet and RBC counts, hematocrit and hemoglobin concentration decreased slightly throughout the pregnancy. The elevation in the plasma [ADO] correlated inversely with the platelet count (r = -0.43, p < 0.05). These results suggest that an increase in the plasma [ADO] in the third trimester may be attributed to the enhanced adenosine release from activated platelets.

Adenosine↗

PubMed1998

Balance of activities of alcohol acetyltransferase and esterase in Saccharomyces cerevisiae is important for production of isoamyl acetate.

Isoamyl acetate is synthesized from isoamyl alcohol and acetyl coenzyme A by alcohol acetyltransferase (AATFase) in Saccharomyces cerevisiae and is hydrolyzed by esterases at the same time. We hypothesized that the balance of both enzyme activities was important for optimum production of isoamyl acetate in sake brewing. To test this hypothesis, we constructed yeast strains with different numbers of copies of the AATFase gene (ATF1) and the isoamyl acetate-hydrolyzing esterase gene (IAH1) and used these strains in small-scale sake brewing. Fermentation profiles as well as components of the resulting sake were largely alike; however, the amount of isoamyl acetate in the sake increased with an increasing ratio of AATFase/Iah1p esterase activity. Therefore, we conclude that the balance of these two enzyme activities is important for isoamyl acetate accumulation in sake mash.

Acetyltransferases↗