Lee Ty

Effects of cryopreservation on meiotic spindles of oocytes and its dynamics after thawing: clinical implications in oocyte freezing--a review article.

Embryo freezing has been a successful practice, but oocyte cryopreservation formerly achieved poorer results. This was mainly due to low rates of survival, fertilization, and development. The major dissimilarities for oocytes to embryos are the character of the plasma membrane, the presence of cortical granules, at the metaphase of meiosis II with the spindle system. In addition, the oocytes must be fertilized by sperm at the appropriate time. To improve the survival rate, a refined slow freezing method with increased sucrose concentration would dehydrate oocytes more sufficiently. Vitrification is another approach to prevent ice crystal formation. Intracytoplasmic sperm injection is used to overcome possible zona hardening from the release of cortical granules. The microtubules of meiotic spindles are vulnerable to the thermal changes and would depolymerize. Cryopreserved oocytes exhibited serious disturbances of the microtubules immediately after thawing. Fertilization of oocytes with disorganized spindles could lead to chromosomal aneuploidy, digyny, and arrest of cleavage. After incubation, the microtubules would repolymerize in a time-dependent way. Normal fertilization and development of cryopreserved oocytes improved after appropriate incubation and timing of insemination, compatible with recovery of the spindles. With the improvement of survival, fertilization, and cleavage, oocyte cryopreservation would gain an imperative role.

Transplacental leakage ofHBeAg-positive maternal blood as the most likely route in causing intrauterine infection with hepatitis B virus

Thirty-two HBeAg-positive carrier mothers and their 32 babies were investigatedto elucidate the mechanism involved in intrauterine infection with HBV. Five mothers had symptoms and signs of threatened abortion and/or threatened preterm labor. Three mothers gave birth more than 6 weeks after the episodes, and their babies were those infected in utero. The other two gave birth within 1 week after the episodes, and the two babies were treated with HBIG immediately after birth; HBV infection was successfully prevented. Therefore we suggest that transplacental leakage of HBeAg-positive maternal blood, which is induced by uterine contractions during pregnancy and the disruption of placental barriers, is the most likely route to cause HBV intrauterine infection.

Sharing of human leukocyte antigens in primary and secondary recurrent spontaneous abortions

The prevalence of recurrent fetal loss and its relationship to sharing of human leukocyte antigens within couples was examined in a large, ethnically homogeneous Chinese population in Taiwan: 91 couples with primary recurrent spontaneous abortion, 32 couples with secondary recurrent spontaneous abortion, and 51 normal fertile couples. There was an excess of human leukocyte antigen sharing in both types of recurrent aborters. The primary aborters shared human leukocyte A and DQ antigens and three or more of the human leukocyte A, B, DR, and DQ antigens. The secondary aborters did not have an excess of sharing at any one locus but they did share three or more of the human leukocyte A, B, DR, and DQ antigens. There was no excess of antipaternal cytotoxic antibodies in any group of aborters, and the primary aborters had a lower level of mixed lymphocyte reaction blocking factor than normal couples or secondary aborters. Previous studies showed that couples in whom a gestational trophoblastic tumor developed in the woman shared human leukocyte B and DQ antigens and three or more of the human leukocyte A, B, DR, and DQ antigens. These studies provide substantial support for the role of recessive genes linked to the major histocompatibility complex in the pathogenesis of recurrent spontaneous abortions and of gestational trophoblastic tumors.

Amniocentesis in mothers who are hepatitis B virus carriers does not expose the infant to an increased risk of hepatitis B virus infection

Sixty-seven pairs of mothers with hepatitis B virus (HBV) surface antigen (HBsAg) and their infants were divided into two study groups to determine the effect of amniocentesis on intrauterine HBV infection. In the first study group (35 pairs), the infants HBsAg status in cord blood was studied and the results were compared with those obtained in the cord blood from 65 infants born to HBsAg-positive women who did not have an amniocentesis. In the second study group (32 pairs), the HBV status of the infants was studied at the age of three months to five years and compared with the HBV status of 3,454 infants in the National HBV Prevention Program. In the first study group, one sample (2.9%) was weakly positive for HBsAg; while in the first control group, two (3.1%) were positive. In the second study group, three (10%) infants were positive for HBsAg. The failure rates of immunoprophylaxis in the second study and control groups were similar (9.4% vs 11% for HBsAg carrier mothers; 30% vs 14% for HBe antigen-positive carrier mothers). This suggested that genetic amniocentesis did not increase the risk of intrauterine HBV infection.

Early predictor of the efficacy of immunoprophylaxis against perinatal hepatitis B transmission: analysis of prophylaxis failure

To research early predictors of the efficacy of the ongoing mass immunoprophylaxis against perinatal hepatitis B virus (HBV) transmission in Taiwan and to analyse the possible causes of immunoprophylaxis failure, 52 hepatitis Be antigen (HBeAg)-positive carrier mothers were recruited for the study. Maternal blood samples were taken at the first and third trimesters and delivery. Umbilical blood was collected and venous blood samples were taken at 4, 7, 11 and 14 months of age. Serum hepatitis B surface antigen (HBsAg) and antibody titres, HBeAg titre and HBV-DNA concentration were analysed. All the umbilical cord blood samples were negative for HBsAg. Among the 52 vaccinated infants, four were poor responders (anti-HBs less than 10 mIU ml-1 before vaccine booster). Another five infants became HBsAg-positive by 4 months of age and remained carriers. All these five carrier mothers were HBV-DNA-positive and three of them had risk factors related to maternal-fetal haemorrhage during pregnancy or delivery. The remaining 43 infants showed protective anti-HBs level (greater than 10 mIU ml-1) by 4 months of age. Three mothers out of these 43 cases also had the same haemorrhage risk factors during pregnancy or delivery, but were HBV-DNA-negative. Therefore, the anti-HBs level at 4 months is a predictor of the success of immunoprophylaxis. It may be helpful to distinguish HBV-DNA-positive carrier mothers among HBeAg-positive ones, to avoid inducing more maternal-fetal haemorrhage in such cases during pregnancy or delivery. Otherwise, additional hepatitis B immune globulin may be indicated in such cases to raise the successful prevention rate.

In Vivo CD3+CD25+ Lymphocyte Subpopulation Is Down‐regulated Without Increased Serum‐Soluble Interleukin‐2 Receptor (sIL‐2R) by Gonadotropin Releasing Hormone Agonist (GnRH‐a)

PROBLEM: To test further whether the suppression of the CD3+CD25+ lymphocyte sub‐population by gonadotropin‐releasing hormone agonist (GnRH‐a) is related to the change in levels of cytokines and soluble interleukin‐2 receptor (sIL‐2R).

The prevalence of recurrent spontaneous abortions cancer, and congenital anomalies in the families of couples with recurrent spontaneous abortions or gestational trophoblastic tumors

This study extends our previous work on the genetics of recurrent spontaneous abortion and of gestational trophoblastic tumors in an ethnically homogeneous population of Chinese in Taiwan by comparing the prevalence of recurrent spontaneous abortions, cancer, and congenital anomalies in the first-, second-, and third-degree relatives of the index couples to that of normally fertile couples from the same population. The rationale for this study was to provide another test for our hypothesis that genes linked to the major histocompatibility complex are responsible for the diseases in the index couples. If they are, these genes should segregate with a higher frequency in the relatives of the index couples than in the relatives of normally fertile couples and lead to a higher prevalence of these diseases in the extended families. Such a difference was found and adds support to our hypothesis that major histocompatibility complex-linked genes affect growth, development, and susceptibility to cancer.

Gonadotropin releasing hormone (GnRH) agonist induces down-regulation of the CD3+CD25+ lymphocyte subpopulation in peripheral blood

PROBLEM: To test whether GnRH agonist could alter in vivo human immune cells and whether the alteration is related to the success of pregnancy in an in vitro fertilization‐embryo transfer (IVF‐ET) program.

Fertilization and embryo cleavage after intracytoplasmic spermatid injection in an obstructive azoospermic patient with defective spermiogenesis

OBJECTIVE To achieve fertilization and cleavage by spermatids without tails from testicular biopsy. DESIGN Clinical trial. SETTING Reproductive unit of a university teaching hospital. PATIENT A patient of obstructive azoospermia with defective spermiogenesis. INTERVENTION Testicular biopsy after scrotal exploration and spermatid injection into the cytoplasm of oocyte. MAIN OUTCOME MEASURES Fertilization and cleavage. RESULTS Four of 13 spermatid injections achieved normal fertilization and 2 of them cleaved. CONCLUSION Intracytoplasmic spermatid injection may be a possible treatment for patients of defective spermiogenesis who have no viable spermatozoa available.

Comparison between a two-layer discontinuous Percoll gradient and swim-up for sperm preparation on normal and abnormal semen samples

PurposeThis work was to compare the effects of Percoll gradient and swim-up treatments for sperm preparation on the percentage of progressive motility, recovery of motile sperm, removal of debris, percentage of normal forms according to strict criteria, and movement characteristics of sperm using computer-assisted velocity analysis.ResultsIn total, 50 semen samples from 50 patients were tested and divided into two groups: a normal group (n=27) with normal parameters and an abnormal group (n=23) with abnormal parameters. The results in both the normal and the abnormal groups revealed that the sperm concentration in the Percoll samples was significantly greater than that in the swim-up samples. Although the percentage of progressive motility was greater in the swim-up samples than in the Percoll samples, the number of motile sperm, reflecting the percentage of motile sperm recovery, was still greater in the Percoll samples. The debris of semen were equally removed by both methods and the percentage of normal forms was also similar in the samples treated according to these two procedures. Both curvilinear velocity (VCL) and straight-line velocity (VSL) of sperm were significantly greater in the swim-up samples than in the Percoll samples. Sperm from the swim-up procedure also showed a greater mean amplitude of lateral head displacement than that from the Percoll gradient procedure, but the distinction was insignificant.ConclusionThe Percoll gradient technique, by recovering more motile sperm, may be applied to prepare oligospermic samples. The swim-up method may become the standard choice to prepare normal semen which could obtain sufficiently motile sperm, due to its simplicity and recovered sperm with superior motility.