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Biomedical subjects

I Wada

Publications and source records attributed to I Wada.

At least 73 records · Page 4Linked to original sources
PubMed1995

Use of buserelin and low-dose human menopausal gonadotropin for in vitro fertilization in women at risk of ovarian hyperstimulation syndrome.

PURPOSE: The purpose of the present study was (i) to assess the value of using a low dose of hMG (75 IU/day) to achieve ovarian stimulation in women who have previously shown an exaggerated response to a standard dose of 150 IU human menopausal gonadotropin/day in a desensitization (group I) or flare-up (group II) protocol and (ii) to determine whether the choice of GnRH-a regimen in a subsequent cycle, namely, a desensitization or flare-up protocol, influenced the effectiveness of the low dose of hMG. RESULTS: In group I, 75% (12/16) and 57% (8/14) of the subsequent desensitization and flare-up protocols, respectively, were cancelled because of inadequate ovarian response. Similarly, the cancellation rates in group II were 10 of 10 and 7 of 11 (64%), respectively. The total cancellation rate (groups I and II together) with the desensitization protocol was higher than that using the flare-up protocol (P < 0.05). CONCLUSION: The simple use of a reduced dose of hMG (75 IU/day) for subsequent in vitro fertilization in women to minimize the risk of the development of ovarian hyperstimulation is of limited benefit since a large proportion then shows an inadequate response. This is particularly pronounced with a subsequent desensitization protocol which does not utilize endogenous gonadotropins to initiate follicular development.

Adult↗
PubMed1995

Diagnosis, prevention and management of ovarian hyperstimulation syndrome.

The overall incidence of clinically important (moderate to severe) OHSS ranges from 1% to 10% of IVF cycles, but only a small proportion (0.5% to 2%) of the cases are severe. In extreme but rare cases, secondary complications such as deep vein thrombosis, respiratory distress and acute hepato-renal failure may occur. The main risk factors are the presence of polycystic ovaries, high ovarian response to superovulation therapy, the use of hCG to trigger the ovulatory process or for luteal phase support, and the endogenous production of hCG by an early pregnancy. The pathogenesis of OHSS is unknown, although the predominant biochemical mediator is thought to be the renin-angiotensin system. Ovarian stimulation should always be carefully monitored to identify those women at risk. In IVF cycles, the hCG injection should be withheld if the risk is judged to be too great. Some women will benefit from a policy of proceeding to collect oocytes, but electively cryopreserving any resulting embryos, thus allowing the ovarian stimulation cycle not to be wasted. The administration of albumin at the time of oocyte collection will reduce the chance of severe OHSS occurring. If a decision is made to proceed with oocyte recovery and embryo transfer, it may be advisable to give 5000 IU of hCG, rather than 10,000 IU, as the ovulatory trigger. Progesterone, and not hCG, should be given in the luteal phase. Women developing mild or moderate OHSS should be kept under outpatient surveillance to detect the minority that may progress to severe OHSS. Those with severe OHSS should be hospitalised for fluid and electrolyte management. Paracentesis under ultrasound guidance is recommended where there are tense ascites, but further surgical intervention should rarely be undertaken and only when there is good clinical evidence of ovarian torsion or haemorrhage.

Female↗
PubMed1994

Molecular cloning of a diacylglycerol kinase isozyme predominantly expressed in human retina with a truncated and inactive enzyme expression in most other human cells.

In order to clone novel diacylglycerol kinase (DGK) isozymes, we first obtained a DGK-related cDNA fragment by polymerase chain reaction using the human hepatoma cell line HepG2 mRNA and degenerated primers. The amplified fragment was subsequently used as a probe for screening the cDNA library from HepG2 cells. We obtained a cDNA clone coding for a novel DGK isozyme (designated DGK gamma) comprised of 791 amino acid residues. The amino acid sequence of DGK gamma was 52 and 62% identical to those of previously sequenced porcine 80-kDa and rat 90-kDa enzymes, respectively. DGK gamma, although initially cloned from the HepG2 cDNA libraries, was unexpectedly expressed in the human retina abundantly and to a much lesser extent in the brain. Other human tissues, including the liver and HepG2 cells, contained extremely low levels of DGK gamma mRNA. Furthermore, HepG2 cells and most of the human tissues except for the retina and brain expressed a truncated DGK gamma with an internal deletion of 25 amino acid residues (Ile451-Gly475). When transfected into COS-7 cells, the nontruncated cDNA gave phosphatidylserine-dependent DGK activity with no apparent specificity with regard to the acyl compositions of diacylglycerol. In contrast the truncated cDNA failed to give DGK activity in spite of the expression of its mRNA and enzyme protein in COS cells, thus demonstrating that the truncated DGK gamma is catalytically inactive. The sequence comparison of the three cloned DGKs revealed the presence of four highly conserved regions including the two sets each of EF-hand and zinc finger structures. Although the implication of the catalytically inactive form of DGK gamma remains unknown, this work further demonstrates the occurrence of multiple animal DGK isozymes with a conserved basic structure but with markedly different expression patterns depending on the cell types.

Amino Acid Sequence↗
PubMed1994

Chaperone function of calnexin for the folding intermediate of gp80, the major secretory protein in MDCK cells. Regulation by redox state and ATP.

The endoplasmic reticulum (ER) not only links the translational machinery to the endomembrane system in eukaryotic cells but also provides a protective environment for the folding of exoplasmic proteins translocated across the ER membrane. Here we describe that the lumenal surface of the ER membranes transiently tethers the folding intermediate of secretory proteins via a 90-kDa ER membrane protein, calnexin. We demonstrate that p70, the precursor to gp80, the major secretory protein in Madin-Darby canine kidney (MDCK) cells, was bound transiently to calnexin in the immediate post-synthetic period (0-10 min) and showed a t1/2 for dissociation from calnexin of 2.5 min. The bound p70 was found to be incompletely folded as assessed by susceptibility to proteinase K digestion. Perturbation of the redox state by 5 mM dithiothreitol or 1 mM diamide markedly inhibited the dissociation of p70 from calnexin (t1/2 > 30 min). Cellular depletion of ATP led to premature dissociation of p70 from calnexin and the formation of p70 aggregates that did not bind calnexin. These findings demonstrate that nascent unfolded p70 is tethered to calnexin during normal protein maturation, including the formation and editing of disulfide bonds and that ATP is required for the productive interaction of gp80 and calnexin.

Adenosine Triphosphate↗
PubMed1994

The benefits of low-dose aspirin therapy in women with impaired uterine perfusion during assisted conception.

The objective of this long-running study was to determine whether the addition of low-dose aspirin to a standard hormone replacement therapy (HRT) protocol improved uterine perfusion during assisted conception. A total of 99 women scheduled for frozen embryo replacement were studied. Endometrial preparation was with a standard buserelin/HRT protocol. Uterine perfusion was assessed by Doppler ultrasound and classified as impaired or normal. In their first attempts, those with impaired perfusion (group I, n = 37) received low doses of aspirin [150 mg (n = 26) or 300 mg daily (n = 11)], starting from day 13 of HRT. Women with normal perfusion (group II) did not receive aspirin. In subsequent attempts, those from group I were arbitrarily allocated to start aspirin on day 1 or day 13 of HRT, and 10 women from group II were arbitrarily selected to receive aspirin from day 1 of HRT. In group I, the cancellation (46 versus 36%) and pregnancy rates (15 versus 25%) in those who received 150 or 300 mg aspirin daily were similar. In those with cancelled first attempts, good perfusion was achieved in 82 versus 20% (P < 0.02) of subsequent attempts using aspirin from day 1 versus day 13 of HRT. Higher pregnancy rates (47 versus 17%) were achieved in those taking aspirin from day 1 of HRT. In group II, pregnancy rates were not statistically different in those who did or did not receive aspirin during their subsequent attempts (10 versus 35%). The addition of low-dose aspirin to a standard HRT protocol in women with impaired uterine perfusion is associated with improved blood flow and satisfactory pregnancy rates.

Aspirin↗
PubMed1994

Birth characteristics and perinatal outcome of babies conceived from cryopreserved embryos.

The objective of this retrospective study was to compare the birth characteristics and perinatal mortality of babies conceived from the use of cryopreserved embryos with those resulting from in-vitro fertilization (IVF) and fresh embryo transfer. A total of 232 consecutive births, one pregnancy termination and a total of 283 babies in the cryopreserved group were studied. The IVF data included 763 births, three terminations and 961 babies, based on a previous analysis. There was no difference in the incidence of twin (18 versus 19%) and triplet births (2 versus 3%) in the cryopreserved and IVF groups respectively. The mean gestational age and birthweight of singleton, twin and triplet births were not significantly different between the groups. No difference was found in the perinatal mortality rates. The incidence of major congenital malformations in the cryopreserved group (1%) was significantly lower than that in the IVF group (3%; P < 0.05). It is concluded that the birth characteristics of babies conceived from cryopreserved/thawed embryos are similar to those from fresh embryos. There are fewer congenital malformations in the cryopreserved group.

Birth Weight↗
PubMed1994

High ovarian response in Yoruba African women during ovulation induction for assisted conception.

Fertile Yoruba women from western Nigeria have a much higher incidence of naturally conceived multizygotic twin and triplet pregnancies than Caucasians. The objective of the present study was to determine whether there are differences between infertile Yoruba and Caucasian women in terms of ovarian response in stimulate cycles for assisted conception. A total of 11 Yoruba women were scheduled for 14 in-vitro fertilization (IVF) and one gamete intra-Fallopian transfer (GIFT) cycles from 1990 to 1992. The Caucasian group consisted of 209 women scheduled for 213 IVF and 22 GIFT cycles during the same period. Buserelin, 500 micrograms subcutaneously daily, was started in the mid-luteal phase to achieve pituitary desensitization. Ovarian stimulation was with variable amounts of menopausal gonadotrophins. Human chorionic gonadotrophin (HCG) was given to trigger the ovulatory process. The Yoruba and Caucasian groups were similar in age and body weight, but significantly more Yorubas (45 versus 11%; P < 0.005) had ultrasound features of polycystic ovary syndrome (PCOS). The serum oestradiol concentration (3024 versus 2058 pg/ml; P < 0.05) and number of follicles > 14 mm in diameter (15.5 versus 9.5; P < 0.05) on the day of HCG were higher in the Yoruba group. The ovarian hyperstimulation syndrome (OHSS) was also more prevalent in the Yoruba group (20 versus 5%; P < 0.05). No difference was found in clinical pregnancy or embryo implantation rates. These results show a higher tendency toward exaggerated ovarian response in infertile Yoruba than Caucasian women, associated with a higher prevalence of PCOS. The risk of developing symptomatic OHSS is higher in Yoruba women.

Embryo Implantation↗
PubMed1993

Assisted conception using buserelin and human menopausal gonadotrophins in women with polycystic ovary syndrome.

OBJECTIVE: To compare the outcome of in vitro fertilisation (IVF) and gamete intrafallopian transfer (GIFT) cycles in women with or without ultrasound features of polycystic ovary syndrome (PCOS). DESIGN: A consecutive series from January to December 1989. SUBJECTS: Twenty-five women with PCOS scheduled for assisted conception. The controls were 139 women with normal ovaries. SETTING: A single centre specialist fertility unit, Manchester, UK. INTERVENTIONS: Pituitary desensitisation was with buserelin. In the PCOS group ovarian stimulation was with 1 ampoule (75 iu FSH) of hMG/day in 12 women (Group I) and two ampoules/day in 13 (Group II). The controls (Group III) were given two ampoules of hMG daily. Human chorionic gonadotrophin (hCG; 10,000 iu) was given when three follicles measured > or = 20 mm diameter. MAIN OUTCOME MEASURES: Serum oestradiol (E2) concentrations, number of follicles, clinical pregnancies, features of the ovarian hyperstimulation syndrome (OHS). RESULTS: Women with PCOS (Groups I or II) had more follicles > or = 14 mm diameter on the day of the hCG injection (P < 0.005), higher serum E2 concentrations on the day after the hCG (P < 0.05) and more oocytes retrieved (P < 0.05) than the controls. The OHS was more prevalent in those with PCOS (32% versus 6.5%; P < 0.05). The clinical pregnancy rate per embryo transfer (27% versus 22%) or gamete transfer (25% versus 39%) and the rate of spontaneous miscarriage (33% versus 12%) were not statistically different. CONCLUSIONS: The pregnancy rate and outcome of pregnancy following IVF or GIFT in women with or without PCOS are similar. Women with PCOS are at a higher risk of developing OHS.

Adult↗
PubMed1993

Does elective cryopreservation of all embryos from women at risk of ovarian hyperstimulation syndrome reduce the incidence of the condition?

OBJECTIVES: To analyse the incidence and factors associated with the ovarian hyperstimulation syndrome (OHS) in our IVF/GIFT programme before and after the introduction of a strategy to cryopreserve all embryos from women judged to be at risk. DESIGN: Two hundred forty-one consecutive IVF/GIFT cycles from January to December 1989. SETTING: Specialist fertility unit, Manchester, UK. INTERVENTIONS: Pituitary suppression was effected by a daily subcutaneous injection of buserelin (500 micrograms) beginning 7 days before the expected menses. The ovarian stimulation was with variable amounts of human menopausal gonadotrophin. Ovulation was induced with 10,000 i.u. human chorionic gonadotrophin (hCG). From January to May (period A), gametes/embryos were replaced and 2000 i.u. hCG given, irrespective of the serum oestradiol (E2) concentration. From June to December (period B), all the embryos from women with an E2 > 3500 pg/ml on the day of ovulatory trigger were electively cryopreserved. MAIN OUTCOME MEASURES: Serum E2, features of moderate or severe OHS, clinical pregnancies. RESULTS: The OHS occurred in 10/105 (9.5%) and 12/136 (8.8%) cycles in periods A and B, respectively. Fewer women (6% versus 60%, P < 0.05) who had their embryos cryopreserved developed severe OHS compared with women with an E2 > 3500 pg/ml who became pregnant after gamete/embryo transfer in period A. The main factors associated with the development of OHS were serum E2 concentrations > 3500 pg/ml, whether gamete/embryos were replaced and the additional hCG given, the occurrence of a pregnancy and the presence of polycystic ovary disease. CONCLUSION: The elective cryopreservation of all embryos from women with high E2 levels reduced the severity, but not the incidence of symptomatic OHS.

Adult↗
PubMed1993

[Clinical investigation of HCV antibodies positive cases in the district with high mortality rate of liver diseases in Saga Prefecture].

The mortality and morbidity rates of chronic liver disease (CLD) have been extremely high for several years at Saga prefecture in Japan. Epidemiological studied revealed districts with high mortality rate of CLD (H-district). We measured C 100-3Ab and HCVCoreAb (CoreAb) in the H-district and observed high discrepancy between C100-3 and CoreAb. In order to examine pathogenesis of this discrepancy, we determined serum HCVRNA in these cases. The positive cases of HCV-Ab among 459 subjects were 33.6% (159). 59 subject were positive for both, 88 were only positive for CoreAb, 7 were only positive for C100-3Ab. Serum HCVRNA was detected in 92% (22/24) of both positive cases, in 67% (6/9) of only CoreAb positive cases, in 43% (3/7) of only C100-3Ab positive cases. These results suggested the cases positive for C-100-3 and CoreAb have chronic liver injury due to HCV infection, while the cases positive for only CoreAb involves healthy carrier or the memory state of HCV infection without liver injury.

Aged↗
PubMed1992

The p88 molecular chaperone is identical to the endoplasmic reticulum membrane protein, calnexin.

We previously described a novel molecular chaperone (designated p88) that participates in the assembly of murine class I histocompatibility molecules (Degen, E., and Williams, D. B. (1991) J. Cell Biol. 112, 1099-1115). Our findings suggest that p88 may either promote proper assembly of class I molecules or retain them, probably within the endoplasmic reticulum (ER), until assembly of the ternary complex of heavy chain, beta 2-microglobulin, and peptide ligand is complete. In this report, we compare p88 to calnexin, a calcium-binding 90-kDa phosphoprotein of the ER membrane (Wada, I., Rindress, D., Cameron, P. H., Ou, W.-J., Doherty, J.-J., II, Louvard, D., Bell, A.W., Dignard, D., Thomas, D. Y., and Bergeron, J. J. M. (1991) J. Biol. Chem. 266, 19599-19610). We show that p88 and calnexin share antigenic epitopes defined by a polyclonal anti-calnexin antiserum. Furthermore, both proteins were immunoprecipitated in association with an intracellularly retained variant of the class I H-2Kb molecule. Since p88 and calnexin were also indistinguishable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, were resistant to digestion with endoglycosidase H, and exhibited virtually identical patterns of peptide fragments following digestion with either V8 protease or trypsin, we conclude that p88 and calnexin represent the same protein. The identification of the p88 chaperone as a phosphorylated, calcium-binding protein of the ER membrane suggests possible means whereby its interaction with class I molecules may be regulated.

Animals↗
PubMed1992

Decrease in beta-subunit phosphotyrosine correlates with internalization and activation of the endosomal insulin receptor kinase.

In a previous study, we showed that the rat hepatic insulin receptor (IR) kinase of endosomes (ENs) was transiently activated to levels exceeding those of plasma membrane (PM) receptors following insulin injection. Phosphatase treatment of EN receptors abolished IR kinase activation implicating beta-subunit autophosphorylation as a mediator of the activation process (Khan, M. N., Baquiran, G., Brule, C., Burgess, J., Foster, B., Bergeron, J. J. M., and Posner, B. I. (1989) J. Biol. Chem. 264, 12931-12940). In the present study, the phosphotyrosine (PY) content of the IR beta-subunit in PM and ENs was estimated by two different methods. In one method, direct in vivo labeling with 32Pi followed by receptor immunoprecipitation was carried out. In the second method, immunoblotting with antibodies against the submembrane domain of the IR beta-subunit, encompassing residue 960 (alpha 960), and with antibodies against PY (alpha PY) was used to determine the content of PY/beta-subunit in PM and ENs following injection of insulin. By both methods, it was found that the PY content of PM IR was significantly greater than that of IR in ENs. With doses of 1.5 micrograms of insulin/100 g body weight (50% receptor occupancy) or 15 micrograms/100 g body weight (receptor saturation), the PY/beta-subunit of PM IR attained a level 2.0 to 2.5-fold of that observed for the IR of ENs. Surprisingly, the IR of ENs incorporated 3 to 5 times more PY/beta-subunit than those of PM consequent to autophosphorylation. Exogenous IR kinase activity (poly(Glu:Tyr)) in PM changed only slightly with insulin dose. In contrast, EN receptors exhibited a dose-dependent increase in kinase activity coincident with the decrease in PY/beta-subunit levels. A comparison of the proportion of receptor and kinase activity immunoprecipitated by alpha PY both before and after autophosphorylation indicated that ENs but not PM contained a small population of lightly phosphorylated but highly activated receptors. Since Thr12-Lys (IR kinase residues 1142-1153) efficiently inhibited IR autophosphorylation of both PM and EN receptors, Tris phosphorylation of beta-subunit regulatory tyrosines was unlikely. These results may be explicable by a dephosphorylation-dependent activation of IR kinase, as seen with the src family of tyrosine kinases.

Amino Acid Sequence↗
PubMed1992

Overlap and discrepancy between tests for anti-C100, anti-GOR and anti-CP9 in patients with chronic liver disease and inhabitants in Saga, Japan.

The authors evaluated the clinical significance of anti-C100, anti-GOR and anti-CP9 in hepatitis C virus (HCV)-related liver disease in two populations: 459 healthy subjects and 385 patients with chronic liver disease (CLD). Previously we reported high rates of mortality and morbidity (5.3%) of CLD in subjects in Saga, Japan. This was ascribed to the high prevalence (10.8%) of anti-HCV among randomized populations, as detected by the C100 ELISA test system, as compared with a finding of 2-3% in Japanese blood donors in the same decade. The incidence of anti-C100, anti-GOR and anti-CP9 detected by ELISA test system in the healthy population currently surveyed was 17.0%, 19.2% and 32.0% respectively, as compared with 75.3%, 60.3% and 73.0% respectively, in those with CLD. The incidence of positivity for at least one of the three antibodies was high (36.4%) among healthy subjects, and even higher (86.5%) among the patients with CLD. In the healthy subjects, incidence of positivity increased with age. The healthy and CLD populations differed in the proportion of cases positive for all three antibodies vs. those positive for at least one antibody: healthy subjects, 52/167, 31.1%, vs. CLD patients, 197/333, 59.2%; P less than 0.01. Among the anti-C100-positive healthy cases, these was a significantly high level of AST, ALT, ZTT and gamma GTP compared with negative cases, with or without anti-GOR and anti-CP9 (P less than 0.01-0.05). These observations suggest that the presence of anti-C100 may be related to the active state of HCV-related liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Association of the tyrosine phosphorylated epidermal growth factor receptor with a 55-kD tyrosine phosphorylated protein at the cell surface and in endosomes.

After the intraportal injection of EGF, the EGF receptor (EGFR) is rapidly internalized into hepatic endosomes where it remains largely receptor bound (Lai et al., 1989. J. Cell Biol. 109:2751-2760). In the present study, we evaluated the phosphotyrosine content of EGFRs at the cell surface and in endosomes in order to assess the consequences of internalization. Quantitative estimates of specific radioactivity of the EGFR in these two compartments revealed that tyrosine phosphorylation of the EGFR was observed at the cell surface within 30 s of ligand administration. However, the EGFR was also highly phosphorylated in endosomes reaching levels of tyrosine phosphorylation significantly higher than those of the cell surface receptor at 5 and 15 min after EGF injection. A 55-kD tyrosine phosphorylated polypeptide (pyp55) was observed in association with the EGFR at the cell surface within 30 s of EGF injection. The protein was also found in association with the EGFR in endosomes as evidenced by coprecipitation studies using a mAb to the EGFR as well as by coelution with the EGR in gel permeation chromatography. Limited proteolysis of isolated endosomes indicated that the tyrosine phosphorylated domains of the EGFR and associated pyp55 were cytosolically oriented while internalized EGF was intraluminal. The identification of pyp55 in association with EGFR in both hepatic plasma membranes and endosomes may be relevant to EGFR function and/or trafficking of the EGFR.

Amino Acid Sequence↗
PubMed1992

Outcome of treatment subsequent to the elective cryopreservation of all embryos from women at risk of the ovarian hyperstimulation syndrome.

From 1st June 1989 to 31st May 1991, 78 women with a serum oestradiol level greater than 3500 pg/ml on the day of the ovulatory trigger, following pituitary suppression with buserelin and ovarian stimulation with human menopausal gonadotrophins (HMG), had all their embryos electively cryopreserved at the pronucleate stage to minimize the risk of developing ovarian hyperstimulation syndrome (OHS). Treatment with buserelin was continued in the luteal phase. A median of 19 oocytes (range 7-43) was obtained and 12 embryos (range 1-37) frozen per cycle. Twenty-one (27%) women developed OHS (six severe). Women developing OHS had higher (P less than 0.05) serum oestradiol concentrations on the 7th day after oocyte retrieval, compared to those who did not. No differences were found for any of the following criteria: aetiology of infertility, age, total dose of HMG, number of oocytes, fertilization rate or freeze-thaw survival of embryos. Subsequently, 125 frozen-thawed embryo replacements have been undertaken, using buserelin and hormone replacement therapy (HRT) (n = 93) or natural cycles (n = 32). The overall freeze-thaw survival and implantation rates per embryo were 71.8 and 11.7%, respectively. The pregnancy rates in natural cycles (19%) and buserelin/HRT cycles (29%) were not significantly different.

Buserelin↗