David Yiu Leung Chan

Dr. David Yiu Leung Chan

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Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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LCLuping Cong
Luping Cong
SWSijia Wang
Sijia Wang
SYSuet Ying Yeung
Suet Ying Yeung
HLHo Sze Jacqueline Lee
Ho Sze Jacqueline Lee
PCPui Wah Jacqueline Chung
Pui Wah Jacqueline Chung
DCDavid Yiu Leung Chan
David Yiu Leung Chan
Ovarian dermoid cysts, also called mature cystic teratomas (MCTs), account for 69% of ovarian germ cell tumors in young women. The tumors are formed by tissues derived from three germ layers, and sebaceous materials are most commonly seen. The origin of MCTs is widely considered to be the germ cell origin, which completes meiosis I. The clinical symptoms vary widely, but 20% of tumors could be asymptomatic. The diagnosis of MCTs is usually made without difficulty by ultrasound and confirmed by histopathology post-operatively. The imaging findings have a high diagnostic value. The typical characteristics present in the sonographic images, including a dermoid plug or Rokitansky nodule, are considered strong evidence for a teratoma. Although the malignant transformation of MCTs is rare, it can occur in some cases, especially in women of advanced age. The treatment of MCTs depends on the risk of malignancy, the age of the patient, and the patient’s fertility reserve requirement. In this article, we review the epidemiology, clinical symptoms, diagnosis criteria, cellular origin, and treatment of mature cystic teratomas.

1 January 2024 in Human Reproduction Open
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CJChristopher J De Jonge
Christopher J De Jonge
CBChristopher L R Barratt
Christopher L R Barratt
RARobert John Aitken
Robert John Aitken
RARichard A Anderson
Richard A Anderson
PBPeter Baker
Peter Baker
MVMónica Hebe Vazquez-Levin
Mónica Hebe Vazquez-Levin
BACKGROUND: The widespread interest in male reproductive health (MRH), fueled by emerging evidence, such as the global decline in sperm counts, has intensified concerns about the status of MRH. Consequently, there is a pressing requirement for a strategic, systematic approach to identifying critical questions, collecting pertinent information, and utilizing these data to develop evidence-based strategies. The methods for addressing these questions and the pathways toward their answers will inevitably vary based on the variations in cultural, geopolitical, and health-related contexts. To address these issues, a conjoint ESHRE and Male Reproductive Health Initiative (MRHI) Campus workshop was convened. OBJECTIVE AND RATIONALE: The three objectives were: first, to assess the current state of MRH around the world; second, to identify some of the key gaps in knowledge; and, third, to examine how MRH stakeholders can collaboratively generate intelligent and effective paths forward. SEARCH METHODS: Each expert reviewed and summarized the current literature that was subsequently used to provide a comprehensive overview of challenges related to MRH. OUTCOMES: This narrative report is an overview of the data, opinions, and arguments presented during the workshop. A number of outcomes are presented and can be summarized by the following overarching themes: MRH is a serious global issue and there is a plethora of gaps in our understanding; there is a need for widespread international collaborative networks to undertake multidisciplinary research into fundamental issues, such as lifestyle/environmental exposure studies, and high-quality clinical trials; and there is an urgent requirement for effective strategies to educate young people and the general public to safeguard and improve MRH across diverse population demographics and resources. LIMITATIONS, REASONS FOR CAUTION: This was a workshop where worldwide leading experts from a wide range of disciplines presented and discussed the evidence regarding challenges related to MRH. While each expert summarized the current literature and placed it in context, the data in a number of areas are limited and/or sparse. Equally, important areas for consideration may have been missed. Moreover, there are clear gaps in our knowledge base, which makes some conclusions necessarily speculative and warranting of further study. WIDER IMPLICATIONS: Poor MRH is a global issue that suffers from low awareness among the public, patients, and heathcare professionals. Addressing this will require a coordinated multidisciplinary approach. Addressing the significant number of knowledge gaps will require policy makers prioritizing MRH and its funding. STUDY FUNDING/COMPETING INTEREST(S): The authors would like to extend their gratitude to ESHRE for providing financial support for the Budapest Campus Workshop, as well as to Microptic S.L. (Barcelona) for kindly sponsoring the workshop. P.B. is the Director of the not-for-profit organization Global Action on Men’s Health and receives fees and expenses for his work, (which includes the preparation of this manuscript). Conflicts of interest: C.J.D.J., C.L.R.B., R.A.A., P.B., M.P.C., M.L.E., N.G., N.J., C.K., AAP, M.K.O., S.R.-H., M.H.V.-L.: ESHRE Campus Workshop 2022 (Travel support—personal). C.J.D.J.: Cambridge University Press (book royalties—personal). ESHRE Annual Meeting 2022 and Yale University Panel Meeting 2023 (Travel support—personal). C.L.R.B.: Ferring and IBSA (Lecture), RBMO editor (Honorarium to support travel, etc.), ExSeed and ExScentia (University of Dundee), Bill & Melinda Gates Foundation (for research on contraception). M.P.C.: Previously received funding from pharmaceutical companies for health economic research. The funding was not in relation to this work and had no bearing on the contents of this work. No funding from other sources has been provided in relation to this work (funding was provided to his company Global Market Access Solutions). M.L.E.: Advisor to Ro, Doveras, Next, Hannah, Sandstone. C.K.: European Academy of Andrology (Past president UNPAID), S.K.: CEO of His Turn, a male fertility Diagnostic and Therapeutic company (No payments or profits to date). R.I.M.: www.healthymale.org.au (Australian Government funded not for profit in men’s health sector (Employed as Medical Director 0.2 FET), Monash IVF Pty Ltd (Equity holder)). N.J.: Merck (consulting fees), Gedeon Richter (honoraria). S.R.-H.: ESHRE (Travel reimbursements). C.N.: LLC (Nursing educator); COMMIT (Core Outcomes Measures for Infertility Trials) Advisor, meeting attendee, and co-author; COMMA (Core Outcomes in Menopause) Meeting attendee, and co-author; International Federation of Gynecology and Obstetrics (FIGO) Delegate Letters and Sciences; ReproNovo, Advisory board; American Board of Urology Examiner; American Urological Association Journal subsection editor, committee member, guidelines co-author Ferring Scientific trial NexHand Chief Technology Officer, stock ownership Posterity Health Board member, stock ownership. A.P.: Economic and Social Research Council (A collaborator on research grant number ES/W001381/1). Member of an advisory committee for Merck Serono (November 2022), Member of an advisory board for Exceed Health, Speaker fees for educational events organized by Mealis Group; Chairman of the Cryos External Scientific Advisory Committee: All fees associated with this are paid to his former employer The University of Sheffield. Trustee of the Progress Educational Trust (Unpaid). M.K.O.: National Health and Medical Research Council and Australian Research Council (Funding for research of the topic of male fertility), Bill and Melinda Gates Foundation (Funding aimed at the development of male gamete-based contraception), Medical Research Future Fund (Funding aimed at defining the long-term consequences of male infertility). M.H.V.-L.: Department of Sexual and Reproductive Health and...

23 July 2018 in Systems Biology in Reproductive Medicine
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XSXiao Shi
Xiao Shi
CCCarol Pui Shan Chan
Carol Pui Shan Chan
TWTarah Waters
Tarah Waters
LCLing Chi
Ling Chi
DCDavid Yiu Leung Chan
David Yiu Leung Chan
TLTin-chiu Li
Tin-chiu Li
In this study, we sought to investigate the effect of lifestyle and demographic factors on classic and functional semen parameters. Three hundred and twenty-eight subjects who underwent semen analysis were recruited. Routine SA, sperm vitality, acrosome reaction (AR) assay and sperm DNA fragmentation index (DFI) were analyzed. Demographic and lifestyle information, including (1) BMI, (2) current smoking and alcohol drinking frequency, (3) sleep habits, (4) daily fluid intake, (5) weekly meat intake, (6) sports frequency, (7) trouser cell phone use, (8) age, and (9) abstinence time, were collected. Generalized additive models were used to analyze the possible non-linear association. The results showed that total sperm count (TSC) was significantly associated with age (P = 0.001), abstinence time (P = 0.001) and daily coffee intake (P = 0.044). Semen volume was significantly associated with age (P < 0.001) and daily coffee intake (P < 0.001). Sperm concentration was significantly associated with abstinence time (P = 0.011) and average sleep duration (P = 0.010). Sperm motility was significantly associated with age (P = 0.002) and daily juice intake (P = 0.001). Total motile sperm count was significantly associated with age (P = 0.003) and abstinence time (P = 0.009). DFI was significantly associated with age (P = 0.002), irregular sleeping habit (P = 0.008) and abstinence time (P = 0.032). The percentage of AR sperm was significantly associated with daily juice intake (P = 0.013). In conclusion, DFI and TSC were the most sensitive semen parameters for demographic and lifestyle features, whereas age had more influence on semen parameters than other demographic and lifestyle features. Abbreviations: BMI: body mass index; SA: semen analysis; AR: acrosome reaction; DFI: DNA fragmentation index; GAM: generalized additive model; TSC: total sperm count; TMC: total motile sperm count; IUI: intrauterine insemination; SCSA: sperm chromatin structure assay; SD: standard deviation; IQR: interquartile range; CBAVD: congenital bilateral absence of vas deferens; NEQAS: national external quality assessment service; HTF: human tubal fluid; HSA: human serum albumin.

24 January 2021 in Journal of Cellular and Molecular Medicine
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MZMingpeng Zhao
Mingpeng Zhao
MXMurong Xu
Murong Xu
HLHanhui Li
Hanhui Li
OAOdai Alqawasmeh
Odai Alqawasmeh
PCPui Wah Jacqueline Chung
Pui Wah Jacqueline Chung
DCDavid Yiu Leung Chan
David Yiu Leung Chan
Selection of the best quality embryo is the key for a faithful implantation in in vitro fertilization (IVF) practice. However, the process of evaluating numerous images captured by time‐lapse imaging (TLI) system is time‐consuming and some important features cannot be recognized by naked eyes. Convolutional neural network (CNN) is used in medical imaging yet in IVF. The study aims to apply CNN on day‐one human embryo TLI. We first presented CNN algorithm for day‐one human embryo segmentation on three distinct features: zona pellucida (ZP), cytoplasm and pronucleus (PN). We tested the CNN performance compared side‐by‐side with manual labelling by clinical embryologist, then measured the segmented day‐one human embryo parameters and compared them with literature reported values. The precisions of segmentation were that cytoplasm over 97%, PN over 84% and ZP around 80%. For the morphometrics data of cytoplasm, ZP and PN, the results were comparable with those reported in literatures, which showed high reproducibility and consistency. The CNN system provides fast and stable analytical outcome to improve work efficiency in IVF setting. To conclude, our CNN system is potential to be applied in practice for day‐one human embryo segmentation as a robust tool with high precision, reproducibility and speed.

28 November 2019 in Environmental Health
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MZMingpeng Zhao
Mingpeng Zhao
HZHaoyang Zhang
Haoyang Zhang
TWTarah H. B. Waters
Tarah H. B. Waters
PCPui Wah Jacqueline Chung
Pui Wah Jacqueline Chung
TLTin Chiu Li
Tin Chiu Li
DCDavid Yiu Leung Chan
David Yiu Leung Chan
Background: Human reproduction follows a seasonal pattern with respect to spontaneous conception, a phenomenon wherein the effect of meteorological fluctuations might not be unique. However, the effect of seasonal variations on patients who underwent in vitro fertilization (IVF) treatment is unclear. We aimed to evaluate the effects of meteorological variation on the pregnancy rate in a cohort undergoing IVF treatment by performing multivariable analyses. Methods: We conducted a cohort study in a sub-tropical region with prominent seasonal variations (2005–2016). Women aged < 35 years who were treated with a long ovarian stimulation protocol and underwent fresh embryo transfer (ER) were included. Data on gonadotropin administration (CYCL), oocyte retrieval (OR), ER, and pregnancy outcomes were prospectively recorded. For each patient, the daily average of meteorological data (temperature, humidity, sunlight duration, solar radiation) was recorded from the date of CYCL to ER. Multiple logistic regression analysis adjusted for age, fertilization method, year of the cycle, gonadotropin dose, and transferred embryo grade was performed to determine the relationship between the meteorological parameters and clinical pregnancy. Patients with one successful cycle and one failed cycle were subtracted for a case-control subgroup analysis through mixed effect logistics regressions. Time-series analysis of data in the epidemic level was conducted using the distributed lag linear and non-linear models (DLNMs). Results: There were 1029 fresh cycles in 860 women (mean age 31.9 ± 2.0 years). Higher mean temperature from CYCL to OR (adjusted odds ratio [aOR] 1.04; 95% confidence interval [CI] 1.01–1.07, P = 0.01) increased the odds of pregnancy, while OR to ER did not show any statistical significance. Compared to that in winter, the odds of becoming pregnant were higher during higher temperature seasons, summer and autumn (aOR 1.47, 95%CI 0.97–2.23, P = 0.07 (marginally significant) and aOR 1.73, 95%CI 1.12–2.68, P = 0.02, respectively). Humidity, sunlight duration, and solar radiation had no effect on the outcome. The subgroup analysis confirmed this finding. The time-series analysis revealed a positive association between temperature and relative risk for pregnancy. Conclusions: In IVF treatment, the ambient temperature variation alters the pregnancy rates; this aspect must be considered when obtaining patient consent for assisted conception.

11 October 2007 in Journal of Neuro-Oncology
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DCDavid Yiu Leung Chan
David Yiu Leung Chan
GCGeorge G. Chen
George G. Chen
WPWai-Sang Poon
Wai-Sang Poon
PLPi C. Liu
Pi C. Liu
Synergy study with chemotherapeutic agents is a common in vitro strategy in the search for effective cancer therapy. For non-chemotherapeutic agents, efficacious synergistic effects are uncommon. Here, we have examined two non-chemotherapeutic agents for synergistic effects: lovastatin and Tumor Necrosis Factor (TNF)-related apoptosis-inducing ligand (TRAIL) for synergistic effects; on three human malignant glioblastoma cell lines, M059K, M59J, and A172. Cells treated with lovastatin plus TRAIL for 48 h showed 50% apoptotic cell death, whereas TRAIL alone (1,000 ng/ml) did not, suggesting that lovastatin sensitized the glioblastoma cells to TRAIL attack. Cell cycle analysis indicated that lovastatin increased G0–G1 arrest in these cells. Annexin V study demonstrated that apoptosis was the predominant mode of cell death. We conclude that the combination of lovastatin and TRAIL enhances apoptosis synergistically. Moreover, lovastatin sensitized glioblastoma cells to TRAIL, suggesting a new strategy to treat glioblastoma.