Joyce Chai
University of Hong Kong
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Featured researches published by Joyce Chai.
Human Reproduction | 2010
Yunao Liu; Suranga P. Kodithuwakku; Pak-Yiu Ng; Joyce Chai; Ernest Hung Yu Ng; William S.B. Yeung; Pak Chung Ho; Kai-Fai Lee
BACKGROUND High serum estradiol (E2) levels following ovarian stimulation lead to reduced implantation and pregnancy rates, yet the underlying mechanisms remain unknown. We investigated if aberrant expression of genes in the Wnt-signaling pathway may be involved. METHODS Microarray and real-time PCR analysis were performed to analyze gene expression profiles of endometrial samples taken at day hCG + 7 in stimulated cycles, and days LH + 7 and LH + 10 in natural cycles. Expression of several Wnt-signaling transcripts, including Dickkopf homolog 1 (DKK1), DKK2 and secreted frizzled-related protein 4 (sFRP4), was analyzed throughout the menstrual cycle. JAr spheroid/Ishikawa endometrial cell co-culture experiments were established to study effects of DKK1 on spheroid attachment in vitro. RESULTS We identified 351 differentially expressed genes. Endometrial samples taken at hCG + 7 had similar expression profiles to those at LH + 10. DKK1 transcripts were up-regulated and DKK2 and sFRP4 were down-regulated in the stimulated compared with LH + 7 group (all P < 0.05). DKK1 transcripts were low in proliferative phase (PS) and increased in late-secretory phase (LS, P < 0.05), although DKK2 peaked in mid-secretory phase (P < 0.05). sFRP4 transcripts were high in PS. Treatment of spheroid with recombinant human DKK-1 protein dose-dependently suppressed (P < 0.05 versus control) spheroids attachment onto endometrial cells (associated with decreased beta-catenin protein): this suppression was nullified by anti-DKK1 antibody. CONCLUSION Gene expression patterns in stimulated cycles resembled those of LS in natural cycles, when the implantation window is about to close, suggesting high serum E2 and/or progesterone concentrations may advance endometrial development, altering the implantation window and possibly decreasing pregnancy rate. Aberrant expression of DKK1 might impair embryo attachment and implantation in vivo.
Fertility and Sterility | 2014
Tracy Wing Yee Yeung; Joyce Chai; Raymond Hang Wun Li; Vivian Chi Yan Lee; Pak Chung Ho; Ernest Hung Yu Ng
OBJECTIVE To evaluate whether pretreatment dehydroepiandrosterone (DHEA) supplementation improves ovarian response markers, ovarian response to standard low-dose gonadotropin stimulation, and in vitro fertilization (IVF) outcomes in poor responders. DESIGN Randomized, double-blind, placebo-controlled pilot study. SETTING Tertiary reproductive medicine unit. PATIENT(S) Thirty-two women with anticipated poor ovarian response. INTERVENTION(S) Randomization into DHEA group (n=16) receiving GNC (25 mg three times a day) or placebo (n=16) starting from at least 12 weeks before the scheduled IVF treatment according to a computer-generated randomization list. MAIN OUTCOME MEASURE(S) Measurement of monthly ovarian response markers, including antral follicle count (AFC), serum antimüllerian hormone (AMH), and follicle-stimulating hormone (FSH) levels; comparison of ovarian response to a standard dose of gonadotropin stimulation at week 8 and IVF outcomes; and AFC after 12 weeks (primary outcome). RESULT(S) The DHEA supplementation resulted in statistically significantly higher serum DHEA-S, free androgen index, and follicular DHEA-S levels. No statistically significant differences in the ovarian response markers (AFC, AMH, or FSH), the ovarian response to standard-dose gonadotropin stimulation, or IVF outcomes were found between the two groups. CONCLUSION(S) No statistically significant improvement in ovarian response markers, ovarian response to standard dose gonadotropin stimulation, or IVF outcomes was found in poor responders receiving pretreatment DHEA. CLINICAL TRIAL REGISTRATION NUMBER HKCTR-1149 (www.hkclinicaltrials.com) and NCT01915186 (www.ClinicalTrials.org).
Human Reproduction | 2009
Joyce Chai; Oi-Shan Tang; Q.Q. Hong; Q.F. Chen; Linan Cheng; Ernest Hung Yu Ng; Pak Chung Ho
BACKGROUND The conventional timing of misoprostol administration after mifepristone for second trimester medical abortion is 36-48 h, but simultaneous administration, which may make the regimen more convenient, has not been studied. The objective of this randomized comparison study is to compare two intervals of administration of misoprostol after pretreatment with mifepristone for second trimester medical abortion. METHODS Eligible women with gestational age between 12 and 20 weeks were randomized to receive mifepristone 200 mg orally followed by 600 microg misoprostol vaginally either immediately or 36-38 h later, followed by 400 microg vaginal misoprostol every 3 h for a maximum of four doses. The primary outcome measure was the success rate at 24 h after the start of misoprostol treatment and the secondary outcome measures were the induction-to-abortion interval and the frequency of side effects. RESULTS There was a significant difference in the success rate at 24 h (36-38 h: 100%; immediate: 91.5%). The median induction-to-abortion interval was significantly shorter in the 36-38 h regimen (4.9 h) compared with the immediate regimen (10 h). Side effects in terms of febrile episodes and chills/rigors were significantly higher in the immediate administration group. CONCLUSIONS Simultaneous use of mifepristone and misoprostol for second trimester medical abortion is not as effective as the regimen using a 36-38 h dosing interval.
Reproductive Toxicology | 2012
Hilda Tsang; Tsz-Yan Cheung; Suranga P. Kodithuwakku; Joyce Chai; William S.B. Yeung; Chris K.C. Wong; Kai-Fai Lee
The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects embryo development, implantation and fertility in humans. The underlying molecular mechanism by which TCDD suppresses implantation remains largely unknown. We used the trophoblastic spheroids (embryo surrogate)-endometrial cells co-culture assay to study the attachment of trophoblastic spheroids (BeWo and Jeg-3) onto the endometrial epithelial (RL95-2 and Ishikawa) cells. TCDD dose-dependently induced cytochrome P450 1A1 (Cyp1A1) expression in trophoblastic and endometrial epithelial cells. Moreover, TCDD at 1 and 10 nM suppressed β-catenin (a Wnt-signaling molecule) and E-cadherin expression, as well as spheroids attachment onto endometrial cells. Interestingly, activation of the canonical Wnt-signaling pathway via Wnt3a or lithium chloride reverted the suppressive effect of TCDD on β-catenin and E-cadherin expressions in the BeWo and RL95-2 cells, and restored the spheroids attachment rate to be comparable to the untreated controls. Taken together, TCDD induces Cyp1A1 expression, modulates the Wnt-signaling pathway and suppresses spheroids attachment onto endometrial cells.
Fertility and Sterility | 2011
Joyce Chai; Kai-Fai Lee; Ernest Hung Yu Ng; William S.B. Yeung; Pak Chung Ho
OBJECTIVE To compare the effect of high serum E(2) levels on endometrial steroid receptors in gonadotropin-stimulated cycles (hCG + 7) and natural cycles (LH + 7), and to study its effect on spheroid attachment. DESIGN Observational. SETTING University hospital. PATIENT(S) Infertile patient with normal menstrual cycles undergoing IVF treatment. INTERVENTION(S) Gonadotropin stimulation and endometrial biopsy; trophoblast spheroid (embryo surrogate, Jeg-3)-endometrial cell (Ishikawa) coculture assay. MAIN OUTCOME MEASURE(S) Steroid receptor expression by quantitative polymerase chain reaction and immunohistochemistry; spheroid attachment rate. RESULT(S) Endometrial biopsies from natural (n = 12) and stimulated (n = 23) cycles were obtained. The expression of estrogen receptor α (ERα) but not ERβ or progesterone receptor (PR) transcript was significantly reduced in stimulated cycles compared with natural cycles. Glucocorticoid receptor (GR) transcript was significantly increased in the excessive responders of the stimulated cycle. There was no difference in ERα immunoreactivity in endometrial stroma, but a higher immunoreactivity was seen in endometrial glands of stimulated cycles. The endometrium of stimulated cycles had a lower expression of PR protein in glands, but a higher expression in stroma. Although no GR protein was detected in glands, GR protein expression was significantly up-regulated in stroma of the stimulated cycles. Endometrial cells treated with high steroid concentrations had a reduced spheroid attachment rate compared with the controls. CONCLUSION(S) High serum E(2) level affects the expression of steroid receptors in the endometrial cells and suppresses spheroid attachment.
Fertility and Sterility | 2014
Vivian Chi Yan Lee; Raymond Hang Wun Li; Joyce Chai; Tracy Wing Yee Yeung; William S.B. Yeung; Pak Chung Ho; Ernest Hung Yu Ng
OBJECTIVE To assess the incidence of P elevation (PE) in natural cycles and evaluate its effect on frozen-thawed embryo transfer cycles performed in natural cycles (FET-NC). STUDY DESIGN Retrospective analysis. SETTING A tertiary assisted reproductive unit. PATIENT(S) Subfertile woman who did not conceive in their stimulated IVF cycle and underwent the first FET-NC cycle. INTERVENTION(S) Achieved serum samples were assayed for P concentrations from the day of LH surge up to 3 days before the surge. The cutoff level of PE was defined as 5 nmol/L. MAIN OUTCOME MEASURE(S) Clinical and ongoing pregnancy rates. RESULT(S) The incidence of PE in natural cycles was 173 of 610 (28.4%). There were no significant differences in both clinical and ongoing pregnancy rates (39.0% vs. 37.3% and 32.5% vs. 31.7%) between those with vs. without PE on the day of LH surge. If PE lasted for 2 days or more, there was a significant reduction in the clinical pregnancy rate (39.4% vs. 20.7%). Using multivariate logistic regression, womens age, PE for 2 days or more, and the number of top-quality embryos were the significant factors for clinical pregnancy rates in FET-NC. CONCLUSION(S) The incidence of PE in FET-NC was similar to that in stimulated cycles. Progesterone elevation for 2 days or more before the LH surge impaired the clinical pregnancy rate of FET-NC, whereas PE on the day of LH surge only did not have such an adverse effect.
Clinical Endocrinology | 2014
Joyce Chai; Wing-Yee T. Yeung; Chi-Yan V. Lee; Hang-Wun R. Li; Pak Chung Ho; Hung-Yu E. Ng
To investigate whether the live birth rate following in vitro fertilization (IVF) is affected by thyroid autoimmunity (TAI) and/or subclinical hypothyroidism in subfertile women.
Acta Obstetricia et Gynecologica Scandinavica | 2011
Joyce Chai; Ting-Chung Pun
Objective. To assess whether early or immediate removal of a 12F in‐dwelling Foley catheter after total abdominal hysterectomy affects the level of subjective pain assessment postoperatively. Design. Randomized controlled trial. Setting. University Hospital. Population. Seventy women underwent total abdominal hysterectomies for various benign gynecological diseases. Methods. Women were randomized to have the urinary catheter removed in the operating room after the surgical procedure or to have it removed on postoperative day 1. Main outcome measures. The primary outcome was patients’ pain assessment and the secondary outcomes were rate of re‐catheterization and symptomatic urinary tract infection. Results. There was no difference in the pain assessment between the two groups. A significantly higher number of urinary retention episodes requiring re‐catheterization were found in the immediate removal group compared with the delayed removal group (20 vs. 0%; p= 0.011). The incidence of symptomatic urinary tract infection did not differ between the two groups. Conclusions. There are pros and cons regarding the policy of one‐day in‐dwelling catheterization compared to immediate catheter removal.
PLOS ONE | 2015
Joyce Chai; Vivian Chi Yan Lee; Tracy Wing Yee Yeung; Raymond Wun-Hang Li; Pak Chung Ho; Ernest Hung Yu Ng
Objective To determine the live birth and cumulative live birth rates of expected poor ovarian responders according to the Bologna criteria and to compare their outcomes with those of expected normal responders Design Retrospective analysis Setting University infertility clinic Patients A total of 1,152 subfertile women undergoing their first in vitro fertilization (IVF) cycle Interventions Women were classified into 4 groups according to the Bologna criteria for comparison Main Outcome Measure(s) Live birth and cumulative live birth rates Results Women with expected poor response (POR) had the lowest live birth rate than the other 3 groups (23.8%, p = 0.031). Cumulative live birth rates were significantly lower in those with expected POR than those with expected normal ovarian response (NOR) (35.8% vs 62.8%, p<0.0001). In the subgroup analysis, the cumulative live birth rates in expected PORs were significantly lower in those who had ≤3 oocytes retrieved (18.6% for ≤3 oocytes vs 44.0% for >3 oocytes, p = 0.006) whereas the live birth rates in fresh cycle did not differ (17.8% vs 30.9%, p = 0.108). Conclusion Women who were expected POR according to the Bologna criteria had lower live birth and cumulative live birth than expected NOR but they still can achieve reasonable treatment outcomes and IVF treatment should not be precluded.
Hong Kong Medical Journal | 2014
Joyce Chai; Tracy Wy Yeung; Vivian Cy Lee; Raymond Hw Li; Estella Yl Lau; William S.B. Yeung; Pak Chung Ho; Ernest Hy Ng
OBJECTIVE To compare the live birth rate, multiple pregnancy rate, and obstetric outcomes of elective single and double embryo transfers. DESIGN Case series with internal comparisons. SETTING University affiliated hospital, Hong Kong. PARTICIPANTS Between October 2009 and December 2011, 206 women underwent their first in-vitro fertilisation cycle. Elective single embryo transfer was offered to women who were aged 35 years or below, and had endometrial thickness of 8 mm or more and at least two embryos of good quality. MAIN OUTCOME MEASURES Live birth rate, multiple birth rate, and obstetric outcomes. RESULTS Among the 206 eligible women, 74 underwent an elective single embryo transfer and 132 a double embryo transfer. The live birth rate was comparable in the two groups, being 39.2% in the elective single embryo transfer group and 43.2% in the double embryo transfer group, while the multiple pregnancy rate was significantly lower in the elective single embryo transfer group than the double embryo transfer group (6.9% vs 40.4%; P<0.001). Gestational ages and birth weights were comparable in the two groups. There was no significant difference between the two groups with respect to the rate of preterm delivery and antenatal complications (27.6% vs 43.9%, respectively; P>0.05). CONCLUSION In this selected population, an elective single embryo transfer policy decreases the multiple pregnancy rate without compromising the live birth rate. The non-significant difference in antenatal complications may be related to the small sample size.