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Biomedical subjects

Y Murata

Publications and source records attributed to Y Murata.

At least 163 records · Page 9Linked to original sources
PubMed2000

Derangement of Purkinje cells in the rat cerebellum following prenatal exposure to X-irradiation: decreased Reelin level is a possible cause.

It has been reported that prenatal X-irradiation of rats during the late gestation period causes heterotopic Purkinje cells in the internal granular layer (IGL) of the abnormally foliated cerebellum. The present study was designed to demonstrate the process of X-ray-induced derangement of Purkinje cells and their surrounding cells. In addition, the expression of some morphoregulatory molecules was examined to determine which molecules are involved in the abnormal pattern of Purkinje cells. Pregnant rats (n = 22) were exposed to 2.5 Gy X-radiation on gestation day 21 and the cerebellum of progeny was examined histologically and by immunohistochemistry to identify Purkinje and Bergmann cells. At 12 h after exposure, extensive cell death was observed in the external granular layer (EGL). By postnatal day (P) 9, while Purkinje cells with well-developed dendrites aligned underneath the EGL in the control cerebellum, Purkinje cells with shorter and abnormally oriented dendrites failed to align and remained in the heterotopic location in the IGL. Bergmann cells and their fibers were also disoriented but later recovered in their proper position. Abnormal folia developed in the irradiated rats. Using immunohistochemistry, we next examined the levels of the neural cell adhesion molecule (NCAM), fibronectin, tenascin, and Reelin. Among them, only the level of Reelin was affected significantly. Reelin decreased strikingly in the premigratory zone of the EGL and IGL in the irradiated cerebellum on P1, and the decrease continued until P9. Decreased Reelin expression was demonstrated quantitatively by Northern blot analysis and the correlation between the mRNA and protein levels was well presented. The expression of reelin mRNA decreased significantly by irradiation from P0, being almost one third of the level in controls on P4, and tended to recover up to P9. It is thus indicated that X-irradiation causes a marked decrease in the level of Reelin at the critical stage for the alignment of Purkinje cells. Since Reelin has been shown to play an important role in the migration of neural cells, it is suggested that the decrease in Reelin by X-irradiation is an important factor for the derangement of Purkinje cells.

Animals↗
PubMed2000

Oncostatin M is produced during pregnancy by decidual cells and stimulates the release of HCG.

Oncostatin M (OSM) is a member of the interleukin-6 superfamily and a multifunctional cytokine that effects the growth and differentiation of many different cell types. OSM concentrations in the sera of pregnant women were found to be significantly higher than those of non-pregnant women. Western blot analysis revealed that the OSM protein was present in the decidua and chorionic tissue in each trimester. Throughout pregnancy, the amount of the OSM protein in the decidua was larger than that in the chorionic tissue. Immunohistochemistry using an anti-OSM monoclonal antibody demonstrated that OSM was mainly localized in the decidual glands and stroma. OSM transcripts in the decidua and the chorionic tissue were detected during each trimester by reverse transcription-polymerase chain reaction (RT-PCR). The regulation of human chorionic gonadotrophin (HCG) release by the placenta in first trimester stimulated with recombinant OSM was also investigated. Stimulation of the placenta by OSM augmented HCG release in a time- and dose-dependent manner. HCG release induced by recombinant human OSM was completely blocked by antibodies against OSM and the signal transducer, gp130, but only partially inhibited by antibodies against the leukaemia inhibiting factor (LIF) receptor. These results suggest that OSM molecules produced by decidual glands and stromal cells during pregnancy have an important role in placental endocrine function.

Antibodies, Monoclonal↗
PubMed2000

Increased concentrations of secretory leukocyte protease inhibitor in peritoneal fluid of women with endometriosis.

Secretory leukocyte protease inhibitor (SLPI) is a potent inhibitor of human leukocyte elastase. We investigated whether SLPI was present in the peritoneal fluid of women with endometriosis and to clarify the role of SLPI in the pathogenesis of endometriosis. Western blot analyses revealed that SLPI protein was detected as a 12 kDa band in peritoneal fluid. The peritoneal fluid concentrations of SLPI, elastase and interleukin-6 were assayed by enzyme-linked immunosorbent assays (ELISA). SLPI concentrations and the SLPI/elastase ratio in the peritoneal fluid of women with endometriosis were higher than in samples from women without endometriosis. There was no significant correlation between concentrations of SLPI and interleukin-6 in the peritoneal fluid. Immunohistochemistry using an anti-SLPI polyclonal antibody revealed positive staining in peritoneal macrophages, but not lymphocytes. The present findings suggest that SLPI found in the peritoneal fluid of patients with endometriosis may contribute to the pathogenesis of endometriosis.

Adult↗
PubMed2000

Alterations in Ca2+-binding on plasma membrane after adaptation to salt stress of tobacco cells in suspension.

Electrophoresis was used to study effects of salinity on the characteristics of Ca2+ binding to the outer surface of plasma membrane (PM) of protoplasts isolated from two types of tobacco (Nicotiana tabacum L., cv. Bright Yellow) cultured cells that were adapted (tolerant) and unadapted (sensitive) to 50 mM NaCl stress. Electrophoretic analysis of salt-sensitive NaCl-unadapted cells shows that Na+ induced an appreciably higher degree of reduction in the amount of Ca2+ bound to PM compared with K+ with increasing concentration from 0.1 to 30 mM. In salt-tolerant NaCl-adapted cells, however, both Na+ and K+ ions induced almost the same degree of reduction in the amount of Ca2+ bound to PM in the physiological concentration range of Ca2+ in the medium between 2 and 4 mM. These results suggest that, under the physiological conditions, PM of salt-sensitive NaCl-unadapted cells has an appreciable amount of PM-bound Ca2+ that is desorbed much easier by Na+ than K+, whereas PM of salt-tolerant NaCl-adapted cells has the PM-bound Ca2+ that can be equally desorbed by Na+ and K+.

Adaptation, Physiological↗
PubMed2000

Comparison of lung perfusion scintigraphic findings in pulmonary thromboembolism in systemic lupus erythematosus, SLE plus antiphospholipid syndrome, and primary antiphospholipid syndrome.

In this study, we compared and reviewed the findings on lung perfusion scans performed in patients with systemic lupus erythematosus (SLE), systemic lupus erythematosus with associated antiphospholipid syndrome (SLE + APS), and primary antiphospholipid syndrome (PAPS), to evaluate the prevalence of pulmonary embolism in restricted samples of the patient groups. Lung perfusion scintigraphy with 99Tc(m)-macroaggregated albumin was performed in 31 patients (SLE = 7; SLE + APS = 14; PAPS = 10). The seven patients with SLE alone and the 10 patients with PAPS had normal perfusion lung scans. Six of the 14 SLE + APS patients showed a segmental uptake defect on multi-view perfusion scans. Thus, the SLE + APS patients were found to have a higher risk of pulmonary thromboembolism than the SLE alone and primary APS patients (P<0.05). The results of our study suggest that lung perfusion scintigraphy should be performed routinely in these patients, even in the absence of pulmonary clinical manifestations, to obtain baseline data for disease outcome and management.

Adult↗
PubMed2000

Thallium-201 myocardial SPET in patients with collagen disease.

We analysed stress 201Tl myocardial single photon emission tomography (SPET) in collagen disease patients to evaluate abnormal uptake patterns and their clinical significance in the assessment of the cardiac status of these patients. The main purpose of the study was to evaluate the clinical significance of reverse redistribution. Twenty-two collagen disease patients (13 with progressive systemic sclerosis (PSS) and nine with systemic lupus erythematosus (SLE)) were examined by 201Tl myocardial SPET with exercise (n = 9) or dipyridamole stress (n = 13). For quantitative analysis, each 201Tl SPET polar map was divided into 17 segments, and the 201Tl uptake pattern of each segment was classified into four types. Eighteen (82%) of the patients showed abnormal findings on 201Tl SPET. Of the 374 segments analysed, 295 (79%) were classified as normal, 16 (4%) as reverse redistribution, 49 (13%) as reversible defect and 14 (4%) as fixed defect. Patients were divided into two groups: those with cardiac abnormalities on conventional testing (Group A, n = 10) and those without (Group B, n = 12). The incidences of fixed defect, reversible defect and reverse redistribution were significantly higher (P <0.01, P <0.0005, P <0.05, respectively) in Group A than in Group B. Nine (90%) of the patients in Group A and nine (75%) in Group B showed abnormal findings. No significant difference was found between the PSS and SLE patients in the incidence of the individual uptake patterns. Stress 201Tl myocardial SPET appears to be an effective method of evaluating a wide spectrum of myocardial involvement in collagen disease patients and in assessing their clinical cardiac status. Reverse redistribution is found to be a significant finding in collagen disease patients.

Adolescent↗
PubMed2000

Dimeric inhibin A as a fourth marker for Down's syndrome maternal serum screening in native Japanese women.

OBJECTIVE: This study was conducted to assess the usefulness of dimeric inhibin A as a fourth marker for Down's syndrome screening in addition to AFP, hCG and uE3 markers for native Japanese women. METHODS: Serum specimens from 367 native Japanese women in the second trimester were assayed for dimeric inhibin A levels. Day specific dimeric inhibin A medians were established for gestational ages 15.0-21.9. Weekly median values for the native Japanese were compared with those of a U.S. population. Selected Japanese specimens from 15 diagnosed Down's syndrome and 3 trisomy 18 cases were also assayed for dimeric inhibin A. RESULTS: Dimeric inhibin A levels did not vary greatly over the gestational age range as expected. Median value comparison showed that native Japanese dimeric inhibin A medians are higher than the U.S. population medians by an average of 7.95%. Native Japanese dimeric inhibin A median values in this study are 1.77 times higher in Down's syndrome cases than in unaffected pregnancies. Trisomy 18 dimeric inhibin A levels show no significant difference from the unaffected pregnancies. CONCLUSIONS: This report shows for the first time that dimeric inhibin A can be informative as a fourth marker for Down's syndrome screening in native Japanese women. We expect the addition of dimeric inhibin A to a triple marker protocol will increase the accuracy of predicted risk for all pregnancies screened and increase the detection rate of Down's syndrome affected pregnancies.

Biomarkers↗
PubMed2000

Triple marker screening for trisomy 21, trisomy 18 and open neural tube defects in singleton pregnancies of native Japanese pregnant women.

OBJECTIVE: To report the results of prenatal triple marker screening on a population of Japanese pregnant women. METHODS: From April 1994 through March 1999, a total of 32,925 native Japanese women with singleton pregnancies requested a triple marker-screening test. Multiples of the median values for 3 markers and individual risks for each patient were calculated following adjustment for the Japanese weight correction factor. The risk cut-off values used for Down syndrome (T21), open spina bifida (OSB) and trisomy 18 (T18) were 1: 295, 1: 290, and 1: 100, respectively. Follow-up information was collected postpartum and statistically analyzed. RESULTS: Detection rates (DR) of T21 for women less than 35 years, over 35 years and overall were 58, 94, and 83%, respectively. DR of T18 for women less than 35 years, over 35 years and overall were 75, 79, and 79%, respectively. DR of open neural tube defects (ONTD) was 100%. CONCLUSIONS: The first cumulative data of an intervention program and prospective follow-up studies in Japan have proven to be similar to other published reports. Individual risk values were calculated for each pregnancy for T21, T18 and ONTD. This screening program is more effective than age-dependent screening for detecting T21, T18 and ONTD pregnancies.

Adult↗
PubMed2000

Changes in cytokine production during and after normal pregnancy.

PROBLEM: The systemic T helper 1/T helper 2 (Th1/Th2) cytokine balance during normal human pregnancy is controversial, and observations about the balance in the postpartum period have only been reported for up to 3 months. METHOD: Whole-blood, from 83 healthy pregnant women, 80 healthy postpartum women, and 31 healthy non-pregnant women was stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin, and the levels of cytokines in the supernatant were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: The production of all measured cytokines decreased during pregnancy, especially in the second trimester. After delivery, interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) increased from 2 to 11 months postpartum, and IL-4 increased from 6 to 11 months postpartum. CONCLUSIONS: These data indicate that 1) decreases in production of both Th1-and Th2-type cytokines during pregnancy may be related to the pregnancy-induced amelioration of autoimmune diseases: 2) increases in production of both Th1- and Th2-type cytokines in the postpartum period may be related to the postpartum aggravation of autoimmune diseases.

Adult↗
PubMed2000

Chromosomal and extrachromosomal synthesis of exfoliative toxin from Staphylococcus hyicus.

Evidence for the existence of two molecular species of exfoliative toxin (ET) synthesized by Staphylococcus hyicus (SHET) under chromosomal and plasmid control is presented. Serological evidence that these molecular species of toxins are distinct from each other is given. The molecular weights of SHET from plasmidless strain P-1 (SHETA) and from plasmid-carrying strains P-10 and P-23 (SHETB) were almost equal. Both of the serotypes of SHET exhibited exfoliation in 1-day-old chickens. The plasmid-cured (P(-)) substrains (P-23C1 and P-23C2) of S. hyicus P-23 did not cause exfoliation in 1-day-old chickens, whereas P(-) substrains (P-10C1 and P-10C2) of strain P-10 caused exfoliation, but they decreased their exfoliative activity. These findings suggest that SHETB was synthesized along with SHETA by strain P-10, whereas the P-23 strain synthesized SHETB alone. The plasmid-carrying strain (P-23) as well as the plasmidless strain (P-1) exhibited the typical clinical signs of exudative epidermitis in pigs. However, plasmid-cured (P(-)) substrains of P-23 (P23C1 and P23C2) did not exhibit the typical clinical signs of exudative epidermitis. These findings suggest that SHETA is synthesized under chromosomal control and SHETB is synthesized under plasmid control and that SHET-producing strains can be divided into three groups: SHETA-producing strains, SHETB-producing strains, and strains producing both toxins.

Animals↗
PubMed2000

Species-specific difference in distribution of voltage-gated L-type Ca(2+) channels of cardiac myocytes.

Ca(2+) influx via sarcolemmal voltage-dependent Ca(2+) channels (L-type Ca(2+) channels) is the fundamental step in excitation-contraction (E-C) coupling in cardiac myocytes. Physiological and pharmacological studies reveal species-specific differences in E-C coupling resulting from a difference in the contribution of Ca(2+) influx and intracellular Ca(2+) release to activation of contraction. We investigated the distribution of L-type Ca(2+) channels in isolated cardiac myocytes from rabbit and rat ventricle by correlative immunoconfocal and immunogold electron microscopy. Immunofluorescence labeling revealed discrete spots in the surface plasma membrane and transverse (T) tubules in rabbit myocytes. In rat myocytes, labeling appeared more intense in T tubules than in the surface sarcolemma. Immunogold electron microscopy extended these findings, showing that the number of gold particles in the surface plasma membrane was significantly higher in rabbit than rat myocytes. In rabbit myocyte plasma membrane, the gold particles were distributed as clusters in both regions that were associated with junctional sarcoplasmic reticulum and those that were not. The findings are consistent with the idea that influx of Ca(2+) via surface sarcolemmal Ca(2+) channels contributes to intracellular Ca(2+) to a greater degree in rabbit than in rat myocytes.

Animals↗
PubMed2000

The controlled release of a drug from biodegradable chitosan gel beads.

Chitosan (CS) forms a gel in solutions with a pH above 12, and the gelation occurs at pH of about 9 in 10% amino acid solutions. In this paper, we investigated the enzymatic degradation and the drug release profile of this novel CS gel beads. The degradability of the CS gel beads was affected by the CS properties, e.g. the degree of deacetylation. The release of prednisolone (PS), as a model drug, from the CS gel beads was sustained significantly compared with the gel prepared with NaOH only. However, the release was not able to be sustained by the increment of NaOH concentration in the solution employed for the preparation of CS gel beads. We also investigated the control of drug release from CS gel beads by application of a complex formed between chondroitin sulfate (Cho) and CS. The release of PS from the CS gel beads treated with Cho was prolonged, and the release pattern was not affected by the treatment time. The time to 50% drug release was about 5 min with PS powder, about 200 min in CS gel beads with 10% glycine (Gly) (pH 9.0), and about 330 min in the CS gel beads with 10% Gly (pH 9.0) treated with Cho. Thus CS gel beads appear promising as a vehicle for sustained drug delivery, and the degradation of CS gel beads may be controlled by the degree of deacetylation of CS.

Chitin↗
PubMed2000

Hydrocephalus in mice following X-irradiation at early gestational stage: possibly due to persistent deceleration of cell proliferation.

The pathogenesis of X-ray-induced congenital hydrocephalus was studied. Pregnant mice were irradiated at 1.4 Gy on gestational day 7 (G7). Four hours after irradiation, extensive cell death was evident in the neuroepithelium and underlying mesoderm of the head region, and proliferating cell nuclear antigen (PCNA)-immunoreactive cells almost disappeared. Embryos with thinner lamina terminalis of the telencephalon, when compared with that of the control, were found in the irradiated group on G9. As early as G11 in some irradiated embryos the telencephalic wall was thinner and lateral ventricles were larger than those of the control. The choroid invagination from the lamina terminalis began on G11 in the control brain, but not in the affected brain. During the following development, fetuses with readily apparent hydrocephalus were consistently found among irradiated fetuses. In these brains the brain mantle was thinner, the corpus striatum and thalamic regions were smaller, and lateral ventricles were larger than those of the control. Even on G11 and G13 the frequencies of PCNA-positive cells in the brain mantle and other brain regions were lower in the hydrocephalic brain than those of the control, suggesting a decelerated proliferation of successive cell generations following exposure to X-rays. The cerebral aqueduct was open in the hydrocephalic brain during the fetal period when the lateral ventricles were dilated. The head was vaulted after birth but the cerebral aqueduct was not completely occluded even in these animals. These findings suggested that cell death in the neuroepithelium followed by a persistent deceleration of neural cell proliferation, resulting in the hypoplasia of brain parenchyma with compensatory ventricular dilatation, is important for the establishment of hydrocephalus.

Animals↗
PubMed2000

Similarity between the effects of carbon-ion irradiation and X-irradiation on the development of rat brain.

The effects of carbon-ion irradiation and X-irradiation on the development of rat brain were compared. Twenty pregnant rats were injected with bromodeoxyuridine (BrdU) at 9 pm on day 18 of pregnancy and divided into five groups. Three hours after injection (day 19.0) one group was exposed to 290 MeV/u carbon-ion radiation by a single dose of 1.5 Gy. Other groups were exposed to X-radiation by 1.5, 2.0 or 2.5 Gy, or sham-treated, respectively. Fetuses were removed from one dam in each group 8 h after exposure and examined histologically. Extensive cell death was observed in the brain mantle from the irradiated groups. The cell death after 1.5 Gy carbon-ion irradiation was remarkably more extensive than that after 1.5 Gy X-irradiation, but comparable to that after 2.0 Gy or 2.5 Gy X-irradiation. The remaining rats were allowed to give birth and the offspring were sacrificed at 6 weeks of age. All of the irradiated offspring manifested microcephaly. The size of the brain mantle exposed to 1.5 Gy carbon-ion radiation was significantly smaller than that exposed to 1.5 Gy X-radiation and larger than that exposed to 2.5 Gy X-radiation. A histological examination of the cerebral cortex revealed that cortical layers II-IV were malformed. The defect by 1.5 Gy carbon-ion irradiation was more severe than that by the same dose of X-irradiation. Although the BrdU-incorporated neurons were greatly reduced in number in all irradiated groups, these cells reached the superficial area of the cortex. These findings indicated that the effects of both carbon-ion irradiation and X-irradiation on the development of rat brain are similar in character, and the effect of 1.5 Gy carbon-ion irradiation compares to that of 2.0-2.5 Gy X-irradiation.

Animals↗
PubMed2000

8-bromo-cyclicAMP stimulates glucose transporter-1 expression in a human choriocarcinoma cell line.

Facilitative glucose transporter-1 (GLUT1) is abundant in trophoblast cells and is responsible for glucose transport in the placenta. However, the change in GLUT expression in human placenta upon trophoblast differentiation remains to be clarified. Therefore, we first examined the localization of GLUT1 and GLUT3 using human first-trimester chorionic villi. We found that GLUT1 and GLUT3 were mainly localized to syncytiotrophoblast and cytotrophoblast cells respectively. We analyzed whether placental GLUT1 and GLUT3 expression changes during differentiation using a human choriocarcinoma (BeWo) cell line which is known to show functional and morphological differentiation in response to cAMP in culture. Treatment of BeWo cells with 8-bromo-cyclicAMP (8-bromo-cAMP) increased the level of hCG secretion and induced cell fusion leading to the formation of large syncytia. Treatment of BeWo cells with 8-bromo-cAMP also resulted in a significant increase in glucose uptake on days 2-3 of culture. The stimulating effect of 8-bromo-cAMP on glucose uptake was concentration dependent. Northern and immunoblot analyses revealed that the levels of mRNA and protein of GLUT1, but not of GLUT3, were significantly increased by 8-bromo-cAMP. These findings suggest that 8-bromo-cAMP stimulates GLUT1 expression with differentiation in BeWo cells.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2000

Changes in actin network during calcium-induced exocytosis in permeabilized GH3 cells: calcium directly regulates F-actin disassembly.

Using digitonin-permeabilized GH3 cells, we investigated both the release of prolactin (PRL) and changes in the cytoskeleton. We determined that permeabilized GH3 cells released PRL in a dose-dependent manner upon addition of micromolar Ca(2+). Phalloidin, a filamentous actin (F-actin) stabilizing agent, inhibited both Ca(2+)-dependent and -independent PRL release, whereas cytochalasin B, a destabilizing agent, had almost no effect on the release. Observation with a confocal laser scanning microscope revealed that F-actin existed mainly in the cortical region in the quiescent state. Increased cytosolic Ca(2+) induced a change in F-actin distribution: F-actin in the cortical region decreased, whereas F-actin inside the cells increased. This change in F-actin distribution was not observed when phalloidin was added. Addition of cytochalasin B induced patchy F-actin spots, but the pattern of the changes of F-actin distribution did not change. The time course of change in F-actin distribution showed that the F-actin network in the cortical region was reduced within 1 min, and Ca(2+)-dependent release of PRL continued for up to 20 min. These results suggest that the F-actin network near the membrane acts as a barrier to exocytosis and that Ca(2+) directly controls the cytoskeletal changes.

Actin Cytoskeleton↗