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Biomedical subjects

H Morikawa

Publications and source records attributed to H Morikawa.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Estimation of passive smoking during pregnancy by cotinine measurement and its effect on fetal growth].

Maternal cigarette smoking has been associated with some complications of pregnancy, including low birth weight and increased morbidity. Recently, it has been reported that maternal passive smoking also affects the fetal environment and causes fetal growth disturbance. In this study, we aimed to investigate the effects of maternal passive smoking on pregnant women and their fetuses by measuring cotinine concentrations in maternal urine and umbilical cord blood. The results were as follows: 1) Among 259 pregnant women, 17 cases (6.6%) were active smokers. The women who were not aware of passive smoking at all, were only 39 cases (15.1%). More than 80% of the pregnant women smoked either passively or actively each day. 2) Cotinine concentrations in both maternal urine and umbilical cord blood increased with the increase in passive smoking. Those in maternal serum, however, did not correlate with the increase in passive smoking. 3) The relative birth weight (R.B.W.) of the newborn infants delivered by the mothers whose cotinine concentration was more than 9.0ng/ml (This value represented the mean +1.5SD of the cotinine concentration in the urine from the mother who did not passively or actively smoke) was significantly lower than that of the mothers whose cotinine concentration was less than 9.0ng/ml. It is concluded that the measurement of the cotinine concentration in maternal urine or umbilical cord blood is very useful in estimating the effects of passive smoking on pregnant women. And passive smoking as well as active smoking also has a harmful effect on the fetal growth mechanism.

Birth Weight↗
PubMed1988

[Studies on the effects of placental lactogen on calcium metabolism during pregnancy].

In order to clarify the dynamics in maternal calcium metabolism during pregnancy, serum concentrations of ionized calcium, calcium regulating hormones and intestinal calcium absorption were measured in pregnant and hypophysectomized(HX) rats. Serum concentrations of ionized calcium decreased significantly late in pregnancy. Serum levels of 1 alpha,25-(OH)2 vitamin D3 (D3) increased late in pregnancy, however, those of parathyroid hormone (PTH) increased not significantly throughout pregnancy. Serum levels of calcitonin(CT) and intestinal calcium absorption increased as pregnancy progressed. Administration of human placental lactogen(hPL), bovine growth hormone(bGH) and ovine prolactin(oPRL) to the HX-rats remarkably enhanced intestinal calcium absorption. Serum concentrations of 1 alpha,25-(OH)2D3 significantly increased by administration of bGH and hPL to the HX-rats, but they did not increase significantly by oPRL administration. These data suggest that 1) maternal intestinal calcium absorption might be increased by the action of increased serum 1 alpha,25-(OH)2D3 and the maternal bone might be kept at the same density throughout pregnancy because serum CT protects the maternal skeleton by resisting the bone-resorption activities of 1 alpha,25-(OH)2D3; and 2) placental lactogen may play an important role on the increase of intestinal calcium absorption by stimulating the production of 1 alpha,25-(OH)2D3 during pregnancy. From these results, it is considered that these alterations of calcium metabolism in the maternal side are the rational responses to supply Ca to the fetus and newborn for keeping their calcium homeostasis.

Animals↗
PubMed1988

[A study on the membrane Na+ efflux of pregnancy-induced hypertension (PIH)].

In order to elucidate the mechanism of pregnancy-induced hypertension (PIH) from the point of view of vascular resistance, we measured the intracellular Na+ concentrations and the membrane Na+ effluxes using red blood cells from normal pregnant females and patients with PIH. We also discussed the influences of hormones such as estrogen, progesterone, dehydroepiandrosterone sulfate (DHAS), hydrocortisol, human placental lactogen (hPL), human chorionic gonadotropin (hCG), and prolactin and parathyroid hormone (PTH) on the membrane Na+ effluxes. The intracellular Na+ concentrations were lower and the Na+-K+-ATPase activities were slightly higher both in the luteal phase and in the first trimester of normal pregnancy than those in the follicular phase, after which the former gradually increased and the latter gradually decreased until term to the mean values of those in the whole menstrual period. In mild PIH, the intracellular Na+ concentrations were not significantly increased, and the Na+-K+-ATPase activities were significantly increased compared to those in the third trimester of normal pregnancy, which suggests the compensatory increase of the Na+-K+-ATPase activities as opposed to the increase of the intracellular Na+ concentrations. In severe PIH, the intracellular Na+ concentrations were significantly increased compared with those in the third trimester of normal pregnancy and slightly increased compared with those in mild PIH, whereas the Na+-K+-ATPase activities were slightly decreased compared with those in mild PIH, which indicates a breakdown of the compensatory increase of the Na+-K+-ATPase activities. The intracellular Na+ concentrations in PIH are significantly correlated to diastolic pressure, systolic pressure and mean blood pressure. When the male red blood cells were incubated with the hormone, dose-dependently the Na+-K+-ATPase activities were significantly elevated by hydrocortisol and slightly elevated by progesterone and hPL, and they were significantly depressed by estrogen and prolactin and slightly depressed by PTH. These results suggest that the peripheral vascular resistance might be increased in the third trimester of normal pregnancy compared with that in the first trimester because the intracellular Na+ concentrations were elevated, and the Na+-K+-ATPase activities in the cell membrane were decreased along the course of pregnancy as a result of the effects of various hormones in the maternal blood.(ABSTRACT TRUNCATED AT 400 WORDS)

Androgens↗
PubMed1988

[Studies on the roles of insulin-like growth factor-1 (IGF-1)/somatomedin C (SMC) during pregnancy].

Studies in human as well as animal experiments have proved that IGF-1/SMC, which shows mitogenic activities in a wide variety of cell types, stimulates growth in vitro and in vivo. The aim of this study was to investigate the roles of IGF-1/SMC on fetal growth during pregnancy by measuring IGF-1/SMC, insulin, C-peptide, human placental lactogen (hPL), and GH and PRL concentrations in maternal and fetal plasma, and by clarifying the changes of IGF receptor in human fetal liver microsomal membranes during pregnancy. Maternal plasma IGF-1/SMC concentrations were not distinguishable from those of nonpregnant women (9.2 +/- 1.7 nmol/l) in the 1st and 2nd trimester of gestation; however, they showed a gradual increase after the 30th week of gestation, reaching 12.7 +/- 5.4 at term. They possessed a significant positive correlation with hPL (r = 0.45, p less than 0.05) and PRL (r = 0.38, p less than 0.05) but not with GH (r = 0.39, NS). On the other hand, IGF-1/SMC in cord plasma could be first detected in the 30th week of gestation, and it increased gradually until term but had no significant correlation with that in maternal plasma. Furthermore, it possessed an intimate correlation with C-peptide (r = 0.30, p less than 0.05) but not with GH or PRL. Additionally, IGF-1/SMC in cord plasma had a positive correlation with birth weight (r = 0.60, p less than 0.005). On the other hand, specific binding of 125I-IGF-1 and -II to liver microsomal membranes which was also displaced by nonlabeled insulin could be detected in human fetuses at various gestational ages. Scatchard analyses indicated that the binding affinity, which was 0.14 +/- 0.05(x 10(9)M-1) in the fetal liver before the 19th week of gestation, increased after the 19th week of gestation (0.58 +/- 0.12); conversely, the binding capacity was lower after the 19th week of gestation (0.15 +/- 0.08 x 10(-12) moles/mg protein) compared with that before the 19th week (0.51 +/- 0.25). These results suggest that (1) plasma IGF-1/SMC might be produced in fetal sites and its regulating mechanism is different from that in maternal sites, and that (2) IGFs might play an important role in human fetal growth and development by its affect via IGF or insulin receptors on the human fetal liver.

C-Peptide↗
PubMed1988

[A study on bone density in women during pregnancy and postpartum].

Although 25-30 grams of calcium is transported into the fetus during pregnancy, it is suggested that the maternal bone might be kept at the same density as in non-pregnant women by measuring serum or urinary calcium concentrations and calcium regulating hormones simultaneously (Ohara et al. Folia Endocrinol., 1986). In this study, the influence of pregnancy on the maternal bone was investigated by measuring the degree of bone density in the second metacarpal bone of pregnant or puerperal women in an X-ray picture using a microdensitometer and a computer (Microdensitometry method; MD method, Inoue et al., 1983). Among six indices provided by this method, d (bone marrow width) tended to increase, but MCI (Barnett's metacarpal index) tended to decrease toward late pregnancy. GSmin, GSmax and sigma GS/D were significantly lower in the third trimester of pregnancy than in the second trimester of pregnancy. The densitometric patterns were A in most of the pregnant and puerperal women, but one case with the pattern of AB and two cases with the pattern of B were found in the third trimester of pregnancy. The sum of the scores of the six indices, which were based on the severity of each index, was within 0-3 in pregnant or puerperal women though it tended to increase as pregnancy progressed. From these results, it was confirmed that maternal bone density was maintained within the normal limits throughout pregnancy and postpartum.

Absorptiometry, Photon↗
PubMed1988

Comparison of the facilitative roles of insulin and insulin-like growth factor I in the functional differentiation of granulosa cells: in vitro studies with the porcine model.

The facilitative effects of insulin and IGF-I were compared in vitro with regard to induction of differentiated functions of porcine granulosa cells. The monolayers were maintained under serum-free conditions in the absence or presence of porcine FSH (20 micrograms/l), with or without graded doses of insulin or IGF-I. Concurrent treatment with IGF-I and FSH produced morphological differentiation and augmented LH/hCG receptor binding together with an enhancement in progesterone and estradiol secretion relative to treatment with FSH alone. IGF-I alone was incapable of exhibiting these effects. Insulin synergized with FSH to facilitate the granulosa cell functions except estradiol secretion. Maximal effective dose of IGF-I was 100 micrograms/l which is within the physiological concentration in vivo, whereas that of insulin was 1.0 mg/l, which is 1000-fold higher than the physiological level. Although the maximal effective doses of IGF-I and insulin produced a comparable increment in progesterone secretion and LH/hCG receptor induction, combined treatment with IGF-I and insulin did not prove additive. [125I]IGF-I binding revealed that specific IGF-I receptors with two classes of binding sites are present on porcine granulosa cells. No distinct differences were detected between IGF-I receptors of granulosa cells from small, medium and large follicles. Insulin was approximately 100-fold less active than IGF-I in competing for [125I]IGF-I binding. These findings suggest that porcine granulosa cells possess specific IGF-I binding sites which may mediate the cytodifferentiative actions of insulin-like peptides. Since IGF-I is more potent than insulin in amplifying the actions of FSH and maximally exerts the cytodifferentiative effects at the physiological concentration, it is likely that IGF-I plays the more important role in granulosa cell differentiation in synergy with FSH.

Animals↗
PubMed1987

[Studies on the dynamics of insulin secretion and the regulatory mechanism of insulin receptor in fetal rats].

In order to clarify the onset of insulin secretion and the regulatory mechanism of its receptor induction in fetus, blood glucose, serum insulin and its hepatic receptor in situ in fetal rats (D18-D21) were measured and the changes of the levels of insulin and its receptor after the direct injection of glucose (1g/kg) to fetal rats in utero were investigated. In fetal rats (D18-D21), both serum insulin and glucose levels increased as pregnancy progresses and specific binding of insulin in fetal liver microsomal membranes increased on D21 of gestation, mainly due to the increase in binding affinity rather than binding capacity. After the direct injection of glucose to the fetus in utero, the rapid increase in serum insulin and the rapid decrease in insulin specific binding to liver microsomal membranes were observed in a part of D20 and all of D21 fetal rats, which was mainly due to the decrease of binding capacity. This suggests that the acute elevation of endogenous insulin level followed by the decrease of insulin specific binding in fetal rat liver is based on the down regulation mechanism of insulin receptor, because the amounts of insulin separated from liver microsomal membranes were less than one twentieth of the insulin concentration which are enough to decrease the binding capacity of hepatic receptor theoretically. In addition, the dissociation of 125I-insulin from liver microsomal membranes of glucose-treated rats were indistinguishable from that of control. From these results, it can be concluded that the onset of glucose-stimulated insulin secretion appears in fetal rats on D20 of gestation and the elevation of endogeneous insulin rapidly down-regulates the number of hepatic insulin receptor in fetal rats.

Animals↗
PubMed1987

[In vitro drug sensitivity test].

Human tumor clonogenic assay(HTCA) not only offers potential advantages for prediction of the sensitivity of individual patients, to anticancer drugs, but also for the development and preclinical testing of prospective new antineoplastic agents. However, HTCA has several theoretical and technical problems, such as a low success rate, the requirement of large numbers of tumor cells and the long time period necessary for evaluation. In order to solve these problems, the MINI-hybrid assay has been developed. We reviewed our experiences to date with chemosensitivity testing by MINI-hybrid assay. Twenty-two of 23 tumors gave evaluable chemosensitivity results (95.6%), and the range of thymidine incorporation for evaluable assays was 7 X 10(2)-1.2 X 10(5)cpm. In addition, the results of drug sensitivity testing of cultured cell lines by MINI-hybrid assay were well correlated with those obtained by HTCA. With its high evaluability rates, the need for fewer cells, the short duration (5 days) required and ease of quantitation, the MINI-hybrid assay is widely applicable to the chemosensitivity testing of human tumors.

Antineoplastic Agents↗
PubMed1986

[Dynamics of calcium metabolism and calcium-regulating hormones in pregnancy-induced hypertension].

Serum concentrations of total calcium, ionized calcium and inorganic phosphorus in severe PIH were significantly lower than those in normal pregnancy during the 3rd trimester of pregnancy and continued to be low even at puerperium. On the other hand, serum concentrations of parathyroid hormone in severe PIH were significantly higher during the 3rd trimester of pregnancy and decreased at puerperium. Any remarkable differences in serum calcitonin levels were not found between severe PIH and normal pregnancy through the last trimester of pregnancy and puerperium. Serum concentrations of 1 alpha, 25-(OH)2 vitamin D3 increased significantly in the 3rd trimester of normal pregnancy, but in severe PIH, their increase was not observed, remaining at the normal levels of non-pregnant women. The kidney functions in the both groups were within the normal limits of non-pregnant women, but placental dysfunction was observed in severe PIH. These results suggest that the decrease in serum calcium and phosphorus levels might have occurred as a result of the decrease in the absorption of calcium and phosphorus from the intestine due to the decrease in serum 1 alpha, 25-(OH)2 vitamin D3 levels and that low serum 1 alpha, 25-(OH)2 vitamin D3 concentrations might be caused by the disturbance of the synthesis in the placenta rather than in the kidney.

Calcitonin↗
PubMed1986

[Calcium metabolism and calcium-regulating hormones during normal pregnancy].

Dynamic changes in maternal and fetal calcium metabolism during pregnancy were investigated by simultaneously measuring serum or urinary concentrations of calcium and calcium regulating hormones. Serum concentrations of total calcium in maternal serum decreased significantly, but those of ionized calcium decreased slightly but not significantly late in pregnancy. Maternal serum levels of parathyroid hormone (PTH) were almost the same as non-pregnant values throughout pregnancy, but those of 1 alpha, 25-(OH)2 vitamin D3 increased as pregnancy progressed. Serum levels of calcitonin (CT) in maternal serum increased late in pregnancy but were statistically not significant. Calcium concentrations in maternal urine during pregnancy showed a slight decrease. It is suggested that calcium absorption in the maternal intestine might be increased by the action of increased serum 1 alpha, 25-(OH)2 vitamin D3, and the maternal bone during pregnancy might be kept at the same density as in non-pregnant women because increased CT protects the maternal skeleton by resisting the bone-resorbing activities of 1 alpha, 25-(OH)2 vitamin D3. The concentrations of ionized calcium and CT in umbilical cord blood were higher, but those of PTH and 1 alpha, 25-(OH)2 vitamin D3 were significantly lower than those of the maternal blood at term. It is considered that an active transport mechanism may be involved in the transplacental supply of calcium, and calcium transport from mother to fetus results in a decrease in the calcium concentrations of the maternal serum. Calcium transported into the fetus may be used as fetal body composition such as accumulation in the bone mainly by the action of serum CT.

Adult↗
PubMed1986

Gene transfer into intact plant cells by electroinjection through cell walls and membranes.

Tobacco mosaic virus (TMV) RNA was introduced directly into mesophyll cells of Nicotiana tabacum var. Samsun using electric-field pulses (electroinjection). The injected gene was successfully expressed in the recipient cells as judged by the assay for the virus coat protein using immunofluorescence and by the virus infectivity assay of the homogenate of the electroinjected cells for local lesions on tobacco leaves. As much as 50% of the cells that survived 24 days after electroinjection showed immunofluorescent specks.

Capsid↗