Publications by authors named "O Wai-Sum"

Article Synopsis
  • Levonorgestrel (LNG) is primarily used as an emergency contraceptive by delaying ovulation, and this study aimed to explore its effects on the human Fallopian tube's ciliary movement and muscle contractions.
  • In an experimental setup using tissue samples from women, the researchers tested LNG at various concentrations to see any changes in ciliary beat frequency and muscular contractions.
  • Results showed that while LNG did not significantly affect ciliary movement or muscle tone, the highest concentration (100 ng/ml) did reduce muscular contractions, indicating that the Fallopian tube is not likely a target for LNG's contraceptive effects at typical emergency contraception doses.
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Prohibitin (PHB), an evolutionarily conserved mitochondrial inner membrane protein, is highly expressed in cells that require strong mitochondrial function. Recently, we demonstrated that the deletion of Phb in spermatocytes results in impaired mitochondrial function. In addition, PHB expression in the mitochondrial sheath of human sperm has a significantly negative correlation with mitochondrial reactive oxygen species levels, but a positive one with mitochondrial membrane potential and sperm motility.

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Previously, we have shown that human sperm Prohibitin (PHB) expression is significantly negatively correlated with mitochondrial ROS levels but positively correlated with mitochondrial membrane potential and motility. However, the possible role of PHB in mammalian spermatogenesis has not been investigated. Here we document the presence of PHB in spermatocytes and its functional roles in meiosis by generating the first male germ cell-specific Phb-cKO mouse.

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Ectopic pregnancy is the major cause of maternal morbidity and mortality in the first trimester of pregnancy. Tubal ectopic pregnancy (TEP) accounts for nearly 98% of all ectopic pregnancies. TEP is usually associated with salpingitis but the underlying mechanism in salpingitis leading to TEP remains unclear.

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Prohibitin (PHB), a major mitochondrial membrane protein, has been shown earlier in our laboratoryto regulate sperm motility via an alteration in mitochondrial membrane potential (MMP) in infertile men with poor sperm quality. To test if PHB expression is associated with sperm mitochondrial superoxide (mROS) levels, here we examined sperm mROS levels, high MMP and lipid peroxidation in infertile men with poor sperm motility (asthenospermia, A) and/or low sperm concentrations (oligoasthenospermia, OA). The diaphorase-type activity of sperm mitochondrial complex I (MCI) and PHB expression were also determined.

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