R Iwasaki

Jichi Medical University, Tochigi, Tochigi-ken, Japan

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Publications (16)33.43 Total impact

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    ABSTRACT: Blood pressure (BP) levels and body mass index (BMI) are known as risk factors for preeclampsia and gestational hypertension. However, there have been few investigations regarding the effects of BP and BMI levels on preeclampsia and gestational hypertension in the same cohort. In the present study, we conducted a retrospective cohort study using multiple logistic regression analysis. The cohort included 1,518 patients without nephritis. The unadjusted odds ratios (ORs) of preeclampsia and gestational hypertension were increased in pregnant women with normal BP (120-129 mmHg systolic or 80-84 mmHg diastolic), high-normal BP and hypertension in the second trimester compared to those with optimal BP. The unadjusted ORs of preeclampsia and gestational hypertension were also increased in obese women in the pre-pregnancy period compared to women with normal range BMI. When adjustment was made for both the BP levels and pre-pregnancy BMI levels, the ORs (95% confidence intervals) of normal BP, high-normal BP, hypertension and obesity for the subsequent occurrence of preeclampsia were 5.1 (2.2-12), 8.3 (3.1-22), 16 (5.0-50) and 2.0 (0.67-5.9), and those for the subsequent occurrence of gestational hypertension were 7.0 (2.6-19), 7.4 (2.1-25), 22 (6.1-83) and 1.3 (0.33-4.8), respectively. For the subsequent occurrence of preeclampsia or gestational hypertension, normal BP, high-normal BP and hypertension in the second trimester may be independent risk factors. Obesity in the pre-pregnancy period, however, may not be an independent risk factor.
    Hypertension Research 04/2006; 29(3):161-7. · 2.79 Impact Factor
  • Shigeki Matsubara, Ryuhiko Iwasaki
    Acta Histochemica Et Cytochemica - ACTA HISTOCHEM CYTOCHEM. 01/2004; 37(6):407-409.
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    ABSTRACT: We examined the fine subcellular morphology of human amniotic epithelial cells and attempted to answer the question as to whether amniotic epithelial cells consist of heterogeneous or homogeneous cells, which has long been controversial. Study subjects were fetal membranes from pregnant women (n=18) who abdominally gave birth to healthy infants at term (37.9+/-0.7 weeks of gestation, mean+/-sd). The methods employed were transmission electron microscopy, enzymehistochemistry, tracer permeability analysis, and freeze-substitution fixation. The labelings for acid phosphatase, cytochrome c oxidase, and CA++ATPase were seen in the lysosomes, mitochondria, and lateral plasma membranes, respectively. The staining distribution pattern of these three enzymes and the morphology of the organelle highlighted by these enzymehistochemistry did not differ among cells. Freeze-substitution fixation revealed that intercellular spaces in the amniotic epithelial cells were narrower than previously thought, but the tracers (horse radish peroxidase and lanthanum nitrate) fully entered these spaces. There were no variations in the tracer permeability among cells. All cells from freeze-substitution fixation exhibited the same morphological features. From these morphological viewpoints, we conclude that human term amniotic epithelial cells consist of a homogeneous cell population.
    European journal of histochemistry: EJH 02/2003; 47(3):223-32. · 2.41 Impact Factor
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    ABSTRACT: To determine whether a rise in systolic blood pressure (SBP) > or = 30 mm Hg and/or diastolic blood pressure (DBP) > or = 15 mm Hg in the absence of hypertension during pregnancy is associated with adverse pregnancy outcomes. We conducted a retrospective, longitudinal study of 1,498 pregnant women without hypertension or proteinuria in the first trimester. The blood pressure levels measured during the first (7.8 +/- 2.3 weeks), second (20.7 +/- 1.2 weeks), and third trimesters (38.6 +/- 1.5 weeks) were analyzed. The perinatal outcome was compared between women who exhibited a rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg during pregnancy (large Delta BP group) and women who did not (small Delta BP group) using one way analysis of variance, chi-square test, or Fisher's exact test. The contribution of gestational hypertension and a large Delta BP to the development of adverse pregnancy outcomes was evaluated using multivariate logistic regression analysis. Of 1441 women who remained normotensive (SBP < 140 mm Hg and DBP < 90 mm Hg) during pregnancy, 238 (16.5%) and 1,203 (83.5%) belonged to the large Delta BP and small Delta BP groups, respectively. There were no significant differences between the two groups in the occurrence rate of gestational proteinuria, preterm deliveries, low-birth-weight infants, or small-for-gestational age infants. A large Delta BP was not a risk factor in itself for the occurrence of gestational proteinuria or small-for-gestational age infants after controlling for the effect of gestational hypertension. A rise in SBP > or = 30 mm Hg and/or DBP > or = 15 mm Hg is not a risk factor of adverse outcome among women who remain normotensive during pregnancy.
    Hypertension in Pregnancy 01/2003; 22(3):275-85. · 0.93 Impact Factor
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    ABSTRACT: It is not known whether women with high blood pressure in the first trimester are likely to exhibit a large increase in blood pressure during pregnancy. We conducted a retrospective, longitudinal study of 1599 pregnant women, among whom 29 women (1.8%) received antihypertensive medication during pregnancy. The blood pressure levels measured during the first (7.9 +/- 2.4 weeks), second (20.7 +/- 1.2 weeks) and third trimesters (38.4 +/- 1.7 weeks) were analyzed. The obstetric outcomes were examined in five subgroups divided according to the quintile of the first-trimester mean arterial pressure level. The net change in blood pressure levels (third-trimester value minus first-trimester value) was significantly inversely correlated with the first-trimester blood pressure levels irrespective of the use or lack of use of antihypertensive drugs. Women with the highest quintile first-trimester mean arterial pressure had the largest body weight, exhibited a fall in blood pressure and had the smallest increase in body weight during pregnancy, and were significantly more likely to have a growth-restricted infant. Women with high initial blood pressure tended to exhibit a fall in blood pressure, whereas women with low initial blood pressure tended to exhibit a large increase in blood pressure during pregnancy. Women with high initial blood pressure and a small increase in body weight during pregnancy tended to have growth-restricted infants.
    Acta Obstetricia Et Gynecologica Scandinavica 11/2002; 81(10):918-25. · 1.85 Impact Factor
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    ABSTRACT: Though various tissue macrophages possess high glucose-6-phosphate dehydrogenase (G6PD) activity, which plays an important role in their phagocytosis/bactericidal function, the presence of this enzyme in human placental villous macrophages (Hofbauer cells) has not been determined. We examined the ultrastructural localization of glucose-6-phosphate dehydrogenase (G6PD) in Hofbauer cells in first and second trimester placental villi, using a newly developed enzyme-cytochemistry (copper-ferrocyanide) method. Electron-dense deposits indicative of G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of Hofbauer cells. Positive and negative cytochemical controls ensured specific detection of enzyme activity. These observations indicated that Hofbauer cells abundantly possessed enzyme-cytochemically detectable G6PD activity. Hofbauer cell G6PD may play a role in placental defense, by supplying NADPH-dependent enzymes (i.e. nitric oxide synthase or NADPH oxidase) with NADPH. This enzyme may also fuel Hofbauer cells with ribose 5-phosphate during their cell proliferation and cell division.
    Placenta 12/2001; 22(10):882-5. · 3.12 Impact Factor
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    ABSTRACT: We examined the ultrastructural localization of glucose-6-phosphate dehydrogenase (G6PD), a NADPH-generating enzyme, in human fetal membranes at various gestational ages, using newly developed enzyme histochemistry (copper-ferrocyanide method). Electron-dense deposits indicative of G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of chorion laeve cytotrophoblasts at various gestational ages. Positive and negative cytochemical controls ensured specific detection of enzyme activity. These observations indicated that chorion laeve trophoblasts were the site of NADPH production. Chorion laeve trophoblast G6PD may play a significant role in fetal membrane physiology, by delivering NADPH to NADPH-dependent oxidoreductases which these cells possess.
    Placenta 08/2001; 22(6):613-6. · 3.12 Impact Factor
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    ABSTRACT: We examined the morphological features of the mitochondria and endoplasmic reticula of chorion laeve cytotrophoblasts from term human fetal membranes, and compared them with those of syncytiotrophoblasts and cytotrophoblasts from human placental villi. Ultrastructural enzyme histochemistry of cytochrome c oxidase and glucose-6-phosphatase were used as cytochemical markers for these intracellular organelles. Chorion laeve cytotrophoblasts possessed abundant endoplasmic reticula, and small mitochondria with a few cristae, which were characteristic of villous syncytiotrophoblasts rather than villous cytotrophoblasts. As for these organellar structures, statistical analysis confirmed similarities between chorion laeve cytotrophoblasts and villous syncytiotrophoblasts, but significant differences between laeve cytotrophoblasts and villous cytotrophoblasts. Though these two cytotrophoblasts originated from one common cell in early placental development, they exhibited quite different organellar morphology during placental/chorioamniotic differentiation. Considering previous data, we concluded that chorion laeve cytotrophoblasts were metabolically active cells, similar to villous syncytiotrophoblasts, performing many functions in fetal membrane physiology.
    Histochemie 08/2001; 116(1):9-15. · 2.61 Impact Factor
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    ABSTRACT: We examined the morphological features of the mitochondria and endoplasmic reticula of chorion laeve cytotrophoblasts from term human fetal membranes, and compared them with those of syncytiotrophoblasts and cytotrophoblasts from human placental villi. Ultrastructural enzyme histochemistry of cytochrome c oxidase and glucose-6-phosphatase were used as cytochemical markers for these intracellular organelles. Chorion laeve cytotrophoblasts possessed abundant endoplasmic reticula, and small mitochondria with a few cristae, which were characteristic of villous syncytiotrophoblasts rather than villous cytotrophoblasts. As for these organellar structures, statistical analysis confirmed similarities between chorion laeve cytotrophoblasts and villous syncytiotrophoblasts, but significant differences between laeve cytotrophoblasts and villous cytotrophoblasts. Though these two cytotrophoblasts originated from one common cell in early placental development, they exhibited quite different organellar morphology during placental/chorioamniotic differentiation. Considering previous data, we concluded that chorion laeve cytotrophoblasts were metabolically active cells, similar to villous syncytiotrophoblasts, performing many functions in fetal membrane physiology.
    Histochemie 06/2001; 116(1):9-15. · 2.61 Impact Factor
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    ABSTRACT: We examined the subcellular localization of ADP-degrading activity and cytochrome c oxidase (CCO) activity in chorion laeve trophoblasts from term and near term human fetal membranes, and compared them with those from severe preeclamptic fetal membranes. The methods used for the detection of enzyme activities were the lead nitrate method for ADP-degrading activity and the diaminobenzidine method for CCO. Precipitates indicative of ADP-degrading activity were visible on surface microvillous plasma membranes of chorion laeve trophoblasts both from normal and preeclamptic fetal membranes. The intensity and distribution patterns were the same in the normal and preeclamptic subjects. CCO labeling was visible in almost all laeve trophoblastic mitochondria both in normal and preeclamptic cases. Previously, we demonstrated that in preeclamptic villous trophoblasts there were decreases in ADP-degrading activity and the presence of CCO-negative mitochondria, which were proposed to lead to dysfunction of each villous trophoblast, and finally to placental insufficiency in preeclampsia. Reductions or changes in enzyme intensities/distribution patterns, which are characteristic features of preeclamptic villous trophoblasts, were absent in chorion laeve trophoblasts in preeclampsia. These results suggest that in preeclampsia there are no, or at least less severe, abnormalities in the enzyme activities of chorion laeve trophoblasts, compared with villous trophoblasts, as far as enzyme-histochemically detectable enzymes are concerned.
    European journal of histochemistry: EJH 02/2001; 45(3):211-7. · 2.41 Impact Factor
  • H Itoi, H Minakami, R Iwasaki, I Sato
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    ABSTRACT: We investigated the long-term effects of oral estriol (E(3)) on serum levels of total cholesterol (t-Cho), high-density lipoprotein cholesterol (HDL-Cho), low-density lipoprotein cholesterol (LDL-Cho), and triglycerides in early menopausal women. We studied 67 healthy early menopausal women who were treated for 48 months with 2.0 mg of E(3) plus 2.5 mg of medroxyprogesterone acetate daily (E(3) group, n=21), 0.625 mg of conjugated estrogen plus 2.5 mg of medroxyprogesterone acetate daily (CE group, n=19), or 1.0 microg of 1alpha-hydroxyvitamin D(3) daily or 1.8 g of calcium lactate containing 250 mg of elemental calcium daily (control group, n=27). The serum levels of t-Cho, HDL-Cho, LDL-Cho, and triglycerides were evaluated at baseline and every 6 months. After 48 months of treatment, the t-Cho decreased significantly by 4.3+/-2.1% (mean+/-SE) from baseline in the E(3) group, did not change in the CE group (-1.9+/-2.1%), and significantly increased (5.4+/-3.4%) in the control group. The HDL-Cho significantly increased in the CE group (10.7+/-2.4%), but not in the E(3) group (3.8+/-3.3%) or in the control group (-3.6+/-3. 0%). The LDL-Cho significantly decreased in the CE group (-11.4+/-4. 0%), did not change in the E(3) group (-5.2+/-3.6%), and significantly increased in the control group (11.8+/-6.3%). The triglyceride level decreased significantly in the E(3) group (-6. 7+/-4.9%), whereas it significantly increased in the CE group (17. 6+/-11.4%), and did not change in the control group (6.1+/-6.4%). Oral E(3) prevented a postmenopausal rise in the t-Cho. Oral estriol did not induce the hypertriglyceridemia that was seen after treatment with conjugated estrogen. Oral E(3) may be a useful alternative therapy in women with hypertriglyceridemia and in women who are reluctant to continue conventional hormone replacement therapy because of uterine bleeding.
    Maturitas 11/2000; 36(3):217-22. · 2.84 Impact Factor
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    ABSTRACT: To evaluate retrospective data concerning patients with adnexal masses that were managed surgically during pregnancy and their effect on fetal outcome. Data were reviewed concerning pregnant women who required surgery at our hospital between 1980 and 1997 for an adnexal mass. In the past 19 years at our hospital a total of 69 Japanese women aged 28.5 +/- 3.4 years (including 2 women with twin pregnancies) were diagnosed with adnexal masses that required surgery. The masses (10.2 +/- 4.5 cm in the largest diameter) were removed at 13.9 +/- 3.7 weeks of gestation. The pathologic features of the 69 lesions were as follows: 33 mature cystic teratomas, 13 functional cysts, 8 mucinous cystadenomas, 6 endometriotic cysts, 4 paraovarian cysts, 3 serous cystadenomas, and 2 malignant neoplasms. Of the 60 patients for whom the outcome of pregnancy was available, 7 (12%) gave birth before 37 weeks of gestation, while 2 (3.3%) experienced spontaneous abortions. There were 3 perinatal deaths among the 60 infants. Two of these 3 infants died due to major anomalies. Although larger studies are required for confirmation, our results suggest that an adnexal mass might be associated with an adverse fetal outcome. Surgical intervention at < 24 weeks of gestation per se might not have been related to the adverse outcomes. We emphasize that surgical intervention during pregnancy can be avoided in patients who have ultrasonographically pathognomonic features of benign cystic teratomas, which are the most common neoplasms operated on during pregnancy.
    Journal of Obstetrics and Gynaecology Research 04/2000; 26(2):89-93. · 0.84 Impact Factor
  • International Journal of Gynecology & Obstetrics 01/2000; 70. · 1.84 Impact Factor
  • International Journal of Gynecology & Obstetrics 01/2000; 70. · 1.84 Impact Factor
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    ABSTRACT: To assess the relation between the preoperative serum level of C-reactive protein (CRP) and the WBC count and the efficacy of emergency cervical cerclage. We retrospectively reviewed the medical records of 17 women (16 singleton pregnancies and 1 twin pregnancy) who underwent emergency cervical cerclage (McDonald technique) between 21 and 26 weeks of gestation. The uterine cervix was dilated >/=3.0 cm and the intact (not ruptured) fetal membranes were visible or protruded into the vagina in all patients. The serum level of CRP and the WBC count were determined preoperatively and postoperatively. Emergency cervical cerclage was considered successful if delivery occurred >/=14 days after the procedure. Emergency cervical cerclage was successful in 12 women, including the woman with a twin pregnancy, but failed in 5 women. The preoperative serum level of CRP and the WBC count were significantly lower and dilatation of the cervix was significantly less in the success group than in the failure group. Cerclage was successful in all eight patients with cervical dilatation </=4.0 cm, but in only 4 of 9 patients with cervical dilatation >4.0 cm (p < 0. 05). Cerclage was successful in all 11 women with a preoperative serum level of CRP </=4.0 mg/dl and a WBC count </=14,000/ microl compared with 1 of 6 women with either a CRP level >4.0 mg/dl or a WBC count >14,000/ microl (p < 0.01). A preoperative CRP value </=4.0 mg/dl, a WBC count </=14,000/ microl, and cervical dilatation </=4.0 cm were significantly associated with prolongation of pregnancy after emergency cervical cerclage.
    Gynecologic and Obstetric Investigation 01/1999; 47(3):157-61. · 1.10 Impact Factor
  • Placenta 01/1998; 19(7). · 3.12 Impact Factor