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Biomedical subjects

Y Ebina

Publications and source records attributed to Y Ebina.

At least 37 records · Page 2Linked to original sources
PubMed2000

Factor XII deficiency in women with recurrent miscarriage.

Congenital thrombophilia is known to cause significant maternal complications, and possibly has an adverse effect on normal fetal development. The aim of this study was to assess the prevalence of factor XII (FXII) deficiency in women with a history of recurrent miscarriage. Two hundred and forty-one consecutive Japanese women with a history of two or more recurrent miscarriages were prospectively assessed for their etiology by conventional screening methods. Seven women were found to have reduced FXII activity (19. 2-46.1%) and prolonged activated partial thromboplastin time (33. 3-51.3 s). Of these 7 women, 6 had experienced early pregnancy losses, while 1 woman had experienced repeated mid-trimester fetal losses with coincidental gestational thrombocytopenia. In 241 women with a history of recurrent miscarriage, the prevalence of FXII deficiency was 2.9%.

Abortion, Spontaneous↗
PubMed2000

Activation of G-protein coupled fMLP or PAF receptor directly triggers glucose transporter type 1 (GLUT1) translocation in Chinese hamster ovary (CHO) cells stably expressing fMLP or PAF receptor.

The chemoattractants, fMLP and PAF, stimulate glucose uptake in phagocytes to obtain an energy source for host defense. Glucose uptake in phagocytes is mainly regulated via glucose transporter type 1 (GLUT1). To examine molecular mechanisms of facilitated glucose uptake in response to fMLP or PAF, we established CHO cells stably expressing fMLP or PAF receptor with c-myc epitope tagged GLUT1 which could immunologically detect GLUT1 on the cell surface. In the CHO cells, both fMLP and PAF directly triggered GLUT1 translocation from the intracellular pool to the cell surface, and stimulated glucose uptake. Therefore, in phagocytes, we propose that fMLP and PAF also trigger GLUT1 translocation to stimulate glucose uptake as an energy source for host defense.

Amino Acid Sequence↗
PubMed2000

Overexpression of wild-type Akt1 promoted insulin-stimulated p70S6 kinase (p70S6K) activity and affected GSK3 beta regulation, but did not promote insulin-stimulated GLUT4 translocation or glucose transport in L6 myotubes.

We have developed a simple, direct and sensitive method to detect GLUT4 on the cell surface. Using this system, we found that PI3-kinase plays a key role in the signaling pathway of insulin-stimulated GLUT4 translocation. One of the down stream effectors of PI3-kinase is serine-threonine kinase Akt (protein kinase B, RAK-PK), but the involvement of Akt in insulin-stimulated GLUT4 translocation is controversial. To investigate whether Akt1 regulates insulin-stimulated GLUT4 translocation and glucose uptake in L6 myotubes, we established L6 myotubes stably expressing c-myc epitope-tagged GLUT4 (GLUT4myc) and mouse wild type (WT) Akt1. We found that overexpression of WT Akt1 promoted insulin-stimulated p70S6 kinase (p70S6K) activity and increased the basal activity of GSK3 beta, but did not promote insulin-stimulated GLUT4 translocation or glucose uptake. These data supported the result that Akt is not a main signaling molecule to transmit the signal of insulin-stimulated GLUT4 translocation or glucose uptake from insulin-activated PI3-kinase.

Amino Acid Sequence↗
PubMed2000

Prevention of lymphocyst formation following systematic lymphadenectomy.

BACKGROUND: The occurrence of pelvic lymphocysts is an important complication following systematic lymphadenectomy for gynecological malignancies. We employed a procedure to prevent vaginal shortening following radical hysterectomy and we examined whether this procedure could be effective in preventing pelvic lymphocyst formation. METHODS: We studied the incidence of lymphocysts in 190 patients with 84 cervical cancers, 74 endometrial cancers and 32 ovarian cancers, using computed tomographic examination at 3 and 6 months subsequent to the surgery. The surgery included radical hysterectomy and a procedure to prevent vaginal shortening (101), modified radical hysterectomy (79) and simple hysterectomy (7), with systematic lymphadenectomy. RESULTS: There was a significant difference in the incidence of pelvic lymphocysts between cervical cancer (4.8%) and ovarian cancer (18.8%). The postoperative incidence of lymphocyst formation in patients undergoing radical hysterectomy with the procedure to prevent vaginal shortening (5.9%) was significantly lower than in those who underwent modified radical hysterectomy (15.2%). CONCLUSION: Our procedure to prevent vaginal shortening could be effective in preventing not only the shortening of the vagina but also the occurrence of pelvic lymphocysts in patients undergoing radical hysterectomy with systematic lymphadenectomy for gynecological malignancies.

Adolescent↗
PubMed1999

Association of stomatin (band 7.2b) with Glut1 glucose transporter.

Employing a monoclonal antibody directed against the C-terminal peptide of glucose transporter molecule 1 (Glut1), we identified a approximately 30-kDa polypeptide which coimmunoprecipitated with Glut1 from sample of human red blood cells (RBC) membranes. The approximately 30-kDa polypeptide reacted with an antibody directed against stomatin, an integral plasma membrane protein which is also present at a high abundance in the human RBC plasma membrane. Likewise, employing anti-stomatin antibody, we found that Glut1 coimmunoprecipitated with stomatin from samples of RBC membranes. However, neither band 3, which is the most abundant integral membrane protein in the RBC, nor actin coimmunoprecipitated with Glut1, indicating a specific interaction between Glut1 and stomatin. Similar to the results obtained in the RBC, Glut1 and stomatin immunoprecipitated with each other in lysates of Clone 9 cells, a rat liver cell line in which Glut1 is expressed at approximately 1/200 the level present in RBC. Employing conditions that resulted in immunoprecipitation of approximately 10% of Glut1 in RBC membranes led to a approximately 3% coimmunoprecipitation of stomatin. A mixed population of Clone 9 cells stably transfected with a plasmid overexpressing the mouse stomatin exhibited 30 +/- 3% reduction in the basal rate of glucose transport compared to control cells or cells stably transfected with the empty vector. The above results suggest that stomatin is closely associated with Glut1 in the plasma membrane and that overexpression of stomatin results in a depression in the basal rate of glucose transport.

Animals↗
PubMed1999

Telomerase activity correlates with histo-pathological factors in uterine endometrial carcinoma.

Telomerase activity has been implicated in the progression of various human tumors. Our aim was to evaluate telomerase activity and to compare it with histo-pathological factors in uterine endometrial carcinoma, to look for possible correlations. Telomerase activity was measured by dilution analysis using a PCR-based telomeric repeat amplification method and detected in 31 of 35 primary endometrial carcinoma tumor specimens. High telomerase activity, detected after 100-fold dilution of extracts, was identified in 15 specimens. There was no significant correlation between the positive telomerase activity and tumor surgical stage or histo-pathological factors. However, high telomerase activity was significantly correlated with advanced surgical stage and with pelvic lymph node metastasis. Our findings suggest that an increase in telomerase activity may be associated with tumor progression and that its level may have a prognostic value in endometrial carcinoma.

Adult↗
PubMed1999

Transient effect of platelet-derived growth factor on GLUT4 translocation in 3T3-L1 adipocytes.

We earlier developed a novel method to detect translocation of the glucose transporter (GLUT) directly and simply using c-MYC epitope-tagged GLUT (GLUTMYC). To define the effect of platelet-derived growth factor (PDGF) on glucose transport in 3T3-L1 adipocytes, we investigated the PDGF- and insulin-induced glucose uptake, translocation of glucose transporters, and phosphatidylinositol (PI) 3-kinase activity in 3T3-L1, 3T3-L1GLUT4MYC, and 3T3-L1GLUT1MYC adipocytes. Insulin and PDGF stimulated glucose uptake by 9-10- and 5.5-6.5-fold, respectively, in both 3T3-L1 and 3T3-L1GLUT4MYC adipocytes. Exogenous GLUT4MYC expression led to enhanced PDGF-induced glucose transport. In 3T3-L1GLUT4MYC adipocytes, insulin and PDGF induced an 8- and 5-fold increase in GLUT4MYC translocation, respectively, determined in a cell-surface anti-c-MYC antibody binding assay. This PDGF-induced GLUT4MYC translocation was further demonstrated with fluorescent detection. In contrast, PDGF stimulated a 2-fold increase of GLUT1MYC translocation and 2.5-fold increase of glucose uptake in 3T3-L1GLUT1MYC adipocytes. The PDGF-induced GLUT4MYC translocation, glucose uptake, and PI 3-kinase activity were maximal (100%) at 5-10 min and thereafter rapidly declined to 40, 30, and 12%, respectively, within 60 min, a time when effects of insulin were maximal. Wortmannin (0.1 microM) abolished PDGF-induced GLUT4MYC translocation and glucose uptake in 3T3-L1GLUT4MYC adipocytes. These results suggest that PDGF can transiently trigger the translocation of GLUT4 and stimulate glucose uptake by translocation of both GLUT4 and GLUT1 in a PI 3-kinase-dependent signaling pathway in 3T3-L1 adipocytes.

3T3 Cells↗
PubMed1999

Mutation of tyrosine 960 within the insulin receptor juxtamembrane domain impairs glucose transport but does not inhibit ligand-mediated phosphorylation of insulin receptor substrate-2 in 3T3-L1 adipocytes.

CSF-1 is equipotent to insulin in its ability to stimulate 2-[3H]deoxyglucose uptake in 3T3-L1 adipocytes expressing the colony stimulating factor-1 receptor/insulin receptor chimera (CSF1R/IR). However, CSF-1-stimulated glucose uptake and glycogen synthesis is reduced by 50% in comparison to insulin in 3T3-L1 cells expressing a CSF1R/IR mutated at Tyr960 (CSF1R/IRA960). CSF-1-treated adipocytes expressing the CSF1R/IRA960 were impaired in their ability to phosphorylate insulin receptor substrate 1 (IRS-1) but not in their ability to phosphorylate IRS-2. Immunoprecipitation of IRS proteins followed by Western blotting revealed that the intact CSF1R/IR co-precipitates with IRS-2 from CSF-1-treated cells. In contrast, the CSF1R/IRA960 co-precipitates poorly with IRS-2. These observations suggest that Tyr960 is important for interaction of the insulin receptor cytoplasmic domain with IRS-2, but it is not essential to the ability of the insulin receptor tyrosine kinase to use IRS-2 as a substrate. These observations also suggest that in 3T3-L1 adipocytes, tyrosine phosphorylation of IRS-2 by the insulin receptor tyrosine kinase is not sufficient for maximal stimulation of receptor-regulated glucose transport or glycogen synthesis.

3T3 Cells↗
PubMed1999

Passive immune thrombocytopenia in neonates of mothers with idiopathic thrombocytopenic purpura: incidence and risk factors.

The aim of this study was to evaluate risk factors for occurrence of neonatal passive immune thrombocytopenia (PIT) in pregnancy complicated by idiopathic thrombocytopenic purpura (ITP). We studied 63 pregnant women with ITP and the 66 neonates retrospectively. Neonatal platelet counts were compared with maternal platelet counts, platelet-associated gamma G immunoglobulin (PAIgG) values, and the presence of antiplatelet antibody in the maternal circulation, history of previous PIT, maternal treatments for ITP, and other maternal or neonatal factors. PIT (platelet counts <100 x 10(3)/microL) was observed in 9 (14.3%) of 63 pregnancies. Presence of circulating antiplatelet antibody in maternal blood, splenectomy prior to pregnancy, and history of previous PIT were observed more frequently with statistical significance in patients giving birth to neonates who developed PIT. No effect on occurrence of PIT was found by the administration of corticosteroids or immunoglobulin. Splenectomy prior to pregnancy was found by logistic regression analysis to be a single significant variable (p = 0.021, odds ratio 7.20, confidence intervals: 1.35 to 38.3) among the risk factors for PIT.

Adrenal Cortex Hormones↗
PubMed1999

Malignant Brenner tumors of the ovary and tumor markers: case reports.

We investigated the tumor marker for malignant Brenner tumors, which had not been established because of the rarity and variable histological criteria. Representative areas of two cases of malignant Brenner tumor were investigated by means of the peroxidase-antiperoxidase method using monoclonal antibody to CA125 and CA72-4 antigen and the streptavidin-biotin immunoperoxidase complex method using monoclonal antibody to SCC antigen. Based on clinical course and immunohistochemical studies, serum CA125 and CA72-4 for Case 1 and SCC and CA72-4 for Case 2 were appropriate tumor markers for the establishment of the extent of tumor burden before treatment and to monitor the response to therapy. The discrepancy of the tumor markers of the two present cases is considered to be a reflection of the difference in the malignant component of these cases. However, serum CA72-4 was an appropriate tumor marker for both malignant Brenner tumors.

Aged↗
PubMed1999

Fetal treatment of congenital heart block ascribed to anti-SSA antibody: case reports with observation of cardiohemodynamics and review of the literature.

PROBLEM: Maternal anti-SSA(B) antibody crosses the placenta and causes fetal myocarditis, congenital heart block (CHB), hydrops fetalis, and intrauterine fetal death. The aim of this study was to evaluate corticosteroids' efficacy as a treatment for CHB. METHOD OF STUDY: One fetus with complete CHB and one fetus with incomplete CHB due to anti-SSA(B) antibody received maternal prednisolone (PSL) and dexamethasone (DEXA) treatments. Heart rate, cardiothoracic ratio (CTR), left ventricular fractional shortening (FS), and preload index (PLI) were longitudinally measured by serial fetal echocardiograms. RESULTS: In the former case, after maternal PSL/DEXA administration, improvement of cardiohemodynamics, i.e., the reduction of PLI from 1.7 to 0.4, CTR from 70 to 52%, and FS from 63 to 54% were observed. In the latter case, second degree 2:1 block was converted to 3:2 block/sinus rhythm, resulting in the increase of the fetal heart rate from 65 to 116 beats per minute (bpm). CONCLUSIONS: We disclosed for the first time the beneficial effects of corticosteroids in the fetal cardiohemodynamics and conduction system of affected fetuses with the presence of maternal anti-SSA(B) antibodies.

Adult↗
PubMed1999

Hypocomplementemia correlates with intrauterine growth retardation in systemic lupus erythematosus.

PROBLEM: The aim of this study was to elucidate fetomaternal risks in systemic lupus erythematosus (SLE)-complicated pregnancy. METHOD OF STUDY: Pregnancy course, complications, and fetal outcome in 82 pregnancies of 55 patients with SLE were investigated. RESULTS: These 82 pregnancies resulted in 14 fetal losses and 66 live births. Without clinical manifestation of SLE-flare, 4 of 8 patients who had low serum complement activity during the pregnancies delivered small-for-date neonates. The rate of the intrauterine growth retardation was significantly higher than that observed in pregnancies with normal complement activity. The frequency of premature deliveries (60%) in patients who received more than 15 mg/day of prednisolone was significantly high when compared with pregnancies maintained by 0-15 mg/day (13.1%). CONCLUSIONS: These data demonstrate the preconceptional and perinatal management necessary in SLE and suggest that the pregnancy with hypocomplementemia, the disease activity, and/or a relatively high maintenance dose of corticosteroid should be carefully managed and monitored.

Adult↗
PubMed1999

GLUT-4myc ectopic expression in L6 myoblasts generates a GLUT-4-specific pool conferring insulin sensitivity.

Insulin stimulates glucose uptake into muscle and fat cells via recruitment of the glucose transporter 4 (GLUT-4) from intracellular store(s) to the cell surface. Robust stimulation of glucose uptake by insulin coincides with the expression of GLUT-4 during differentiation of muscle and fat cells, but it is not known if GLUT-4 expression suffices to confer insulin sensitivity to glucose uptake. We have therefore examined the effect of expression of a myc epitope-tagged GLUT-4 (GLUT-4myc) into L6 myoblasts, which do not express endogenous GLUT-4 until differentiated into myotubes. Ectopic expression of GLUT-4myc markedly improved insulin sensitivity of glucose uptake in L6 myoblasts. The GLUT-4myc protein distributed equally to the cell surface and intracellular compartments in myoblasts, and the intracellular fraction of GLUT-4myc further increased in myotubes. In myoblasts, the intracellular GLUT-4myc compartment contained the majority of the insulin-regulatable amino peptidase (IRAP) but less than half of the GLUT-1, suggesting segregation of GLUT-4myc and IRAP to a specific cellular locus. Insulin stimulation of phosphatidylinositol 3-kinase and protein kinase B-alpha activities was similar for L6-GLUT-4myc myoblasts and myotubes. At both stages, GLUT-4myc responded to insulin by translocating to the cell surface. These results suggest that GLUT-4myc segregates into a specific compartment in L6 myoblasts and confers insulin sensitivity to these cells. L6-GLUT-4myc myoblasts, which are easily transfectable with various constructs, are a useful resource to study insulin action.

Aminopeptidases↗
PubMed1999

Fluoromicroscopic detection of myc-tagged GLUT4 on the cell surface. Co-localization of the translocated GLUT4 with rearranged actin by insulin treatment in CHO cells and L6 myotubes.

We earlier developed a novel method to detect translocation of glucose transporter type 4 (GLUT 4) directly, quantitatively and simply using c-MYC epitope-tagged GLUT4 (GLUT4myc) Kanai F, Nishioka Y, Hayashi H, Kamohara S, Todaka M, Ebina Y: J Biol Chem 268: 14523-14526, 1993). We further developed the method to visualize GLUT4myc on the cell surface++ by fluorescence microscope using a highly sensitive immunochemical detection system in tissue culture cells stably expressing GLUT4myc. The translocation of GLUT4myc was observed on stimulation with insulin in 3T3-L1 adipocytes, CHO cells and L6 myotubes stably expressing GLUT4myc. Platelet-derived growth factor (PDGF), norepinephrine and bradykinin also triggered GLUT4 translocation in CHO-GLUT4myc cells stably expressing each receptor. To observe the distribution of GLUT4 and actin after insulin treatment, double staining for GLUT4myc and actin was performed. Translocated GLUT4myc on the cell surface was co-localized with rearranged actin in CHO cells and L6 myotubes. This result suggests that a correlation exists between GLUT4 translocation and actin rearrangement.

3T3 Cells↗
PubMed1998

Cox multivariate regression models for estimating prognosis of patients with endometrioid adenocarcinoma of the uterine corpus who underwent thorough surgical staging.

The International Federation of Gynecology and Obstetrics (FIGO) adopted surgical staging criteria in 1988. Many studies have shown that histologic grade, nuclear grade, lymph-vascular space invasion and cell type are also important predictors of survival. It has not been clarified, however, how to integrate these histopathologic variables into the process of estimating individual prognosis. We performed Cox multivariate regression analysis to create models that incorporate various histopathologic factors for estimating the prognoses of patients with endometrioid adenocarcinoma of the uterine corpus. Our study was based on data from 206 patients who underwent complete surgical staging, including systematic pelvic and para-aortic lymph node dissection. Two models resulted: one included depth of myometrial invasion, para-aortic node metastasis and the number of sites involved by the tumor among the cervix, ovary and pelvic lymph nodes (which we designated as extracorporeal spread score, ECS) and the other incorporated nuclear grade and lymph-vascular space invasion as variables. These 2 models enabled the prognosis for patients with endometrioid adenocarcinoma to be stratified into several levels according to hazard ratio. Comprehensive integration of the histopathologic prognostic factors, categorized into those relating to tumor extent and those relating to tumor virulence, should facilitate the estimation of individual prognosis more accurately than FIGO staging alone.

Adenocarcinoma↗
PubMed1998

Reconstitution of insulin signaling pathways in rat 3Y1 cells lacking insulin receptor and insulin receptor substrate-1. Evidence that activation of Akt is insufficient for insulin-stimulated glycogen synthesis or glucose uptake in rat 3Y1 cells.

Rat 3Y1 cells have endogenous insulin-like growth factor-1 receptors and insulin receptor substrate (IRS)-2, but lack both insulin receptor (IR) and IRS-1. To investigate the role of IR and IRS-1 in effects of insulin, we transfected IR and IRS-1 expression plasmids into cells and reconstituted the insulin signaling pathways. 3Y1 cells stably expressing the c-myc epitope-tagged glucose transporter type 4 (3Y1-GLUT4myc) exhibit no effects of insulin, at physiological concentrations. The 3Y1-GLUT4myc-IR cells expressing GLUT4myc and IR responded to phosphatidylinositol 3,4, 5-trisphosphate (PI-3,4,5-P3) accumulation, Akt activation, the stimulation of DNA synthesis, and membrane ruffling but not to glycogen synthesis, glucose uptake, or GLUT4myc translocation. The further expression of IRS-1 in 3Y1-GLUT4myc-IR cells led to stimulation of glycogen synthesis but not to glucose uptake or GLUT4myc translocation in response to insulin, although NaF or phorbol 12-myristate 13-acetate did trigger GLUT4myc translocation in the cells. These results suggest that, in rat 3Y1 cells, (i) IRS-1 is essential for insulin-stimulated glycogen synthesis but not for DNA synthesis, PI-3,4,5-P3 accumulation, Akt phosphorylation, or membrane ruffling, and (ii) the accumulation of PI-3,4,5-P3 and activation of Akt are insufficient for glycogen synthesis, glucose uptake or for GLUT4 translocation.

Amino Acid Sequence↗
PubMed1998

Effect of growth hormone on the translocation of GLUT4 and its relation to insulin-like and anti-insulin action.

To elucidate the effect of growth hormone (GH) on the insulin signal transduction pathway leading to the translocation of glucose transporter-4 (GLUT4), we constructed Chinese hamster ovary cells that overexpressed GH receptor and GLUT4. Treatment with GH triggered GLUT4 translocation, and this translocation was completely inhibited by wortmannin. GH-induced GLUT4 translocation reached a maximum level after 30 min, and then gradually decreased and returned to the basal level after 2 h. Tyrosine phosphorylation of JAK2 also became maximal after 30 min and then gradually decreased. In contrast, GLUT4 translocation remained unchanged for 2 h after insulin treatment, and tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) also remained constant for up to 2 h. Chronic GH treatment had almost no effect on insulin-stimulated Akt kinase activation and GLUT4 translocation. These results suggest that GH and insulin translocate GLUT4 in a similar manner, at least in part, and the difference in translocation depends on the difference in the tyrosine phosphorylation of JAK2 and IRS-1. The anti-insulin action of GH after chronic GH treatment does not appear to be mainly due to the inhibition of GLUT4 translocation.

Androstadienes↗