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Biomedical subjects

A Itakura

Publications and source records attributed to A Itakura.

67 records · Page 4Linked to original sources

Improvement of ischemic myocardial dysfunction by nisoldipine.

We examined the cardioprotective effect of nisoldipine against myocardial dysfunction during ischemia and reperfusion in Langendorff perfused rabbit hearts. Nisoldipine was administered to the hearts before 60 minutes of global ischemia. This agent inhibited the increase of end-diastolic pressure during ischemia and also improved the recovery of left ventricular developed pressure and coronary flow during reperfusion in a concentration-dependent manner. The maximal cardioprotective effect was observed in 10(-8) M nisoldipine. The beneficial effect was associated with an increase of coronary flow during reperfusion. Therefore, both the nisoldipine-increased coronary flow during reperfusion and the inhibition of ischemic contracture by nisoldipine seem to play a crucial role in improving myocardial dysfunction of ischemic-reperfused hearts.

Animals↗

Studies on transmission of hepatitis C virus from mother-to-child in the perinatal period.

To elucidate whether breast milk, vaginal discharge and contamination with maternal blood at birth are possible routes of mother-to-child transmission of hepatitis C virus (HCV), we examined HCV RNA in the cord and peripheral blood of infants, and in the blood, vaginal discharge, and breast milk of anti-HCV seropositive mothers. From July 1991 to July 1992, we studied 20 healthy pregnant women, who were seropositive with the Ortho anti-HCV EIA, and their infants. Using a sensitive nested polymerase chain reaction (nested PCR), we investigated the presence or absence of hepatitis C virus in the above-mentioned specimens. Moderate elevation of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) was observed in only one woman in the first and third trimesters. The nested PCR and subsequent Southern hybridization detected 0.5-5.5 copies of HCV c-DNA. HCV RNA was detected in 17/20 blood samples (85%), 7/14 vaginal discharge samples (50%) and 4/10 cord blood samples (40%). However, no HCV RNA was identified in the peripheral blood of infants or breast milk. The mother-to-child transmission of HCV at delivery or via breast milk does not appear to contribute much to maintaining the global HCV reservoir.

Adult↗

Differential distribution of placental leucine aminopeptidase/oxytocinase and aminopeptidase A in human trophoblasts of normal placenta and complete hydatidiform mole.

Placental leucine aminopeptidase (P-LAP)/oxytocinase (OTase) degrades several small peptides such as oxytocin (OT), arginine vasopressin (AVP) and angiotensin III (ANGIII), and aminopeptidase A (AP-A) converts angiotensin II (ANGII) to ANGIII. These proteases play an important role in foetal growth and the maintenance of human homeostasis during pregnancy. In this study, we confirmed the distribution of P-LAP and AP-A proteins and messenger RNAs in human trophoblasts in normal placenta and complete hydatidiform mole by immunohistochemical and in-situ hybridization techniques. Immunoreactivity of P-LAP was mainly noted in the apical membrane of syncytiotrophoblasts, and the expression of messenger RNA (mRNA) for P-LAP was predominantly noted in the cytoplasm of syncytiotrophoblastic cells. However, immunoreactivity of AP-A was mainly noted in the apical membrane of cytotrophoblasts and in the basal zone of the syncytiotrophoblasts, and the expression of mRNA for AP-A was predominantly noted in cytoplasm of cytotrophoblastic cells and a little in cytoplasm of syncytiotrophoblastic cells. Thereby, the two proteases were differentially distributed both in normal placenta and hydatidiform mole throughout the gestational age. These results are useful for the further understanding of not only the pathophysiology of pregnancy, but also the pathogenesis of trophoblastic diseases.

Adult↗