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Biomedical subjects

S U Chen

Publications and source records attributed to S U Chen.

At least 55 records · Page 3Linked to original sources
PubMed1995

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. METHODS: Thirty-six infertile patients were enrolled under the long protocol of GnRH agonist (buserelin acetate) and superovulation with gonadotropin from our IVF-ET program. Peripheral B cells, NK cells, CD4+ and CD8+ T cells, and the expression of CD69, CD25, HLA-DR, and CD71 antigens on the T cells were serially examined by dual-color flow cytometry. RESULTS: B cells, NK cells, CD8+ T cells, and CD71+ T lymphocyte subpopulations were not changed throughout the whole course of treatment. CD4+ T cell and CD25+ T cell subpopulations were significantly down-regulated when the GnRH agonist was used for approximately 2 wk. CD3+CD69+, CD3+CD25+, and CD3+DR+ lymphocyte subpopulations were increased at 7 days (during implantation) and at 14 days after embryo transfer in pregnant patients, but not in patients who failed to get pregnant. CONCLUSIONS: The GnRH agonist had a transiently immunosuppressive effect on CD4+ and CD25+ T cells, but CD69+, CD25+, and HLA-DR+ T cells were activated during and after successful implantation.

Adult↗
PubMed1995

Decidual natural killer cytotoxicity decreased in normal pregnancy but not in anembryonic pregnancy and recurrent spontaneous abortion.

PROBLEM: The natural killer (NK) cell activity is depressed in the decidua of early normal pregnancy. Recently Morii et al. (Am J Reprod Immunol 1993;29:1-4) found that all early intradecidual CD3+ T cells expressed either T cell receptor (TCR) alpha/beta or gamma/delta but that the expression of the CD3+/TCR complex was down-regulated. METHOD: To test whether these changes in decidual cellular immunity are different among normal pregnancy, anembryonic pregnancy and recurrent spontaneous abortion, we examined the immune cell subpopulations in the decidua from these three types of pregnancy using flow cytometry and an NK cytotoxicity assay. RESULTS: Intradecidual CD3+ T cells expressed either TCR alpha/beta or gamma/delta, and the level of expression of the CD3/TCR complex was down-regulated in normal pregnancy, anembryonic pregnancy, and recurrent spontaneous abortion. Although the relative proportion of decidual NK cells was increased to approximately the same extent in all three types of pregnancy, decidual NK activity was higher in anembryonic pregnancies and in recurrent spontaneous abortions than it was in normal pregnancies. CONCLUSION: Decidual NK cell responses are different in anembryonic pregnancies and in recurrent spontaneous abortions than in normal pregnancies. Whether this difference is pathogenic or is the response to a dead embryo remains to be elucidated.

Abortion, Habitual↗
PubMed1995

Interleukin-1 beta (IL-1 beta) is increased in the follicular fluids of patients with premature luteinization.

PROBLEM: Most, but not all, studies indicate that premature luteinization correlates with poor pregnancy outcome in in-vitro fertilization (IVF) programs. It remains unclear whether cytokines (IL-1 beta, TNF alpha), the established immune mediators, play a role in regulation or initiation of an abnormal follicular or embryo development in patients with premature luteinization. METHODS: Levels of cytokines (IL-1 beta, TNF alpha), estradiol (E2) progesterone (P4), and androstenedione (A'ione) were examined in 18 preovulatory follicular fluid (FF) samples from patients with premature luteinization (group 1) and 3 FF samples from patients without premature luteinization (group 2). The number of oocytes recovered, fertilization rate, and pregnancy outcome were evaluated in these two groups. RESULT: IL-1 beta (25.4 +/ 11.9 pg/ml, mean +/ SD) and TNF alpha (13.4 +/ 10.7 pg/ml) were present in these FF samples. The mean level of IL-1 beta in group 1 was significantly higher than that in group 2 (37.3 +/ 12.3 vs. 20.0 +/ 7.6 pg/ml; P < 0.00001) and the mean level of E2 was significantly lower in group 1 than that in group 2 (1064 +/ 686 vs. 1570 +/ 641 ng/ml; P = 0.02). The levels of TNF alpha, P4, and A'ione showed no distinction between these two groups. There was no correlation between the levels of either IL-1 beta or TNF alpha and P4, E2 or A'ione. The fertilization rate in group 1 (62/77; 80%) was similar to that in group 2 (124/160; 78%). Five of 7 patients in group 1 and seven of 20 patients in group 2 achieved pregnancy following embryo transfer. One of five pregnancies in group 1 aborted. CONCLUSION: The exaggerated levels of IL-1 beta in patients with premature luteinization may arise from accumulation of this cytokine owing to sustained high LH stimulation, and this may be a protective response to the abnormal LH surge and function to inhibit prematurely increased secretion of P4. These data indicate the important role of LH in the induction of IL-1 beta secretion and the possible regulatory action of IL-1 beta in luteinization. According to the diminution of E2 in group 1, there may be a subtle atretic process progressing in follicles primed with prematurely elevated LH. However, the detrimental effect of premature luteinization, if it exists, may work at the stage ¿during or after implantation.

Abortion, Spontaneous↗
PubMed1995

Effect of assisted hatching by partial zona pellucida dissection on mouse embryos in vitro.

The zonae pellucida of mouse embryos were dissected to examine the effect of partial zona dissection (PZD) at the four-cell stage on embryonic development and the hatching process in vitro. Micropipettes were used to create a gap of one-sixth the zona circumference, to avoid damage to the blastomere. A total of 484 embryos at the four-cell stage (defined as day 2 embryos) were randomly divided into two groups, the PZD group (n = 238) and the control group (n = 246). Embryos of both groups were cultured in vitro under identical conditions and examined on the following day. The hatching rates were as follows: day 3, 11/238 (4.6%) in the PZD group and 0/246 (0%) in the control group; day 4, 105/238 (44.1%) in the PZD group and 54/246 (22.0%) in the control group; day 5, 71/238 (29.8%) in the PZD group and 36/245 (14.5%) in the control group. On day 4 the rates of complete hatching were 7/238 (2.9%) in the PZD group and 2/246 (0.8%) in the control group. On day 6 they were 88/238 (37.0%) in the PZD group and 66/246 (26.8%) in the control group. A significantly higher percentage of PZD embryos than controls initiated and completed hatching in similar culture conditions. The present study indicates that the creation of an opening in the zona pellucida is not harmful to embryonic development and may facilitate hatching. Whether the enhanced hatching ability of embryos in vitro caused by PZD can improve the implantation rate requires further study.

Animals↗
PubMed1995

Heterotopic pregnancies after controlled ovarian hyperstimulation and assisted reproductive techniques.

Eight cases of heterotopic pregnancy following assisted reproductive techniques (ART) were reviewed. One cervical, three cornual and four tubal pregnancies were combined with intrauterine pregnancies. The cervical ectopy was successfully treated with a local injection of potassium chloride (KCl) into the gestational sac. A viable baby was produced from the intrauterine gestation. Cornual metroplasties were performed on two ruptured and one unruptured cornual heterotopic pregnancies. One of these three cases was maintained till term. All four tubal heterotopic pregnancies were aborted. Widespread application of ART in recent years has meant that heterotopic pregnancies are no longer a rarity. Both physicians and patients should be made aware that the existence of an intrauterine gestation does not preclude the risk of nidation of other fetuses in ectopic sites. The authors recommend that detailed ultrasound studies, preferably via the vaginal route, should be performed on patients in ART programs. During the examination, the adnexae should be carefully evaluated, even if an intrauterine gestational sac is already present. If a heterotopic pregnancy is diagnosed, the appropriate treatment depends on the location of ectopic pregnancy. Local injection with KCl or methotrexate is effective in certain types of cervical or cornual ectopic pregnancy, as it may allow the conservation of the intrauterine pregnancy.

Adult↗
PubMed1994

Peptides extracted from Vero cell cultures overcome the blastocyst block of mouse embryos in a serum-free medium.

PURPOSE: The aim of this work was to evaluate the effect of a Vero cell coculture system on the development of mouse embryos. METHODS: Mouse embryos were randomly divided and cultured in human tubal fluid (HTF) medium with/without Vero cell monolayers, conditioned medium (CM) obtained from Vero cell cultures, and HTF medium supplemented with peptides extracted from CM. The concentrated CM was examined by SDS/PAGE. RESULTS: The development of mouse embryos was blocked at the blastocyst stage in pure HTF medium (1.4% hatching at day 5). This "blastocyst block" was overcome by coculture with Vero cell monolayers (48.1% hatching at day 5; 1.4 vs 48.1%; P < 0.001). CM and the addition of 5% fetal bovine serum (24.1 and 34.9% hatching, respectively, at day 5) were also able to enhance the process of hatching. In the other experiment, the addition of peptides extracted from Vero cell cultures also overcame the blastocyst block (12.5%) compared with pure HTF medium (2.1%) (P < 0.05). Electrophoretic separation revealed several classes of polypeptides consistently secreted into CM obtained from Vero cell cultures. Most peptides occurred in the M(r) range between 6.5 kd and 35.9 kd. CONCLUSION: A developmental block (blastocyst block) of mouse embryos in a serum- and protein-free medium (HTF) was discovered in this study. This block was effectively overcome by HTF plus serum and coculture with Vero cell monolayers and also by the peptides extracted from Vero cell-conditioned medium. We speculate that certain factors secreted or converted by Vero cells may be critical in hatching of mouse embryos. Further study of these factors may be helpful in delineating its mechanism.

Animals↗
PubMed1994

Sharing of human leukocyte antigens in couples with unexplained infertility affects the success of in vitro fertilization and tubal embryo transfer.

OBJECTIVE: The purpose was to test further our hypothesis that genes, or genetic defects, linked to the major histocompatibility complex affect reproduction by correlating human leukocyte antigen sharing with the success or failure of in vitro fertilization and tubal embryo transfer in couples having unexplained infertility. STUDY DESIGN: Seventy-six couples with unexplained infertility who failed superovulation and intrauterine insemination at least three times were typed for human leukocyte antigens and treated by in vitro fertilization and tubal embryo transfer. The results were correlated with the sharing of human leukocyte antigens in the couples. RESULTS: Thirty-four of the women had successful pregnancies, 36 did not become pregnant, and six became pregnant but aborted shortly thereafter. There was a highly significant excess of human leukocyte antigen sharing in the couples who failed treatment: three of the A, B, DR, and DQ antigens (p = 0.015) or two of the B, DR, and DQ antigens (p = 0.015). No specific human leukocyte antigen alleles were present in excess. CONCLUSIONS: Genes, or genetic defects, linked to the major histocompatibility complex significantly affect the success of in vitro fertilization and tubal embryo transfer just as they affect the prevalence of recurrent spontaneous abortion, cancer, and congenital anomalies. It appears as if the critical genes, or genetic defects, are located in the B-DR-DQ region of the major histocompatibility complex.

Abortion, Spontaneous↗
PubMed1994

Co-culture with Vero cell monolayer maintains the motility of asthenozoospermic semen samples.

The clinical effectiveness of co-culture with Vero (Green monkey kidney) cell monolayer in maintaining the motility and viability of fresh asthenozoospermic semen (18 samples) and frozen-thawed semen with poor motility (motility fraction < 50%) (15 samples) in a 24-h period was evaluated. Co-culture with Vero cell monolayer in human tubal fluid (HTF) medium for 24 h resulted in a statistically better maintenance of motility percentage (P < 0.005), mean amplitude of lateral head displacement (ALH) (P < 0.005), and mean track speed (VCL) (P < 0.05) than culture in HTF medium alone. However, these motility parameters (motility percentage, ALH, VCL) declined soon after removal of spermatozoa from the monolayer. Co-culture with Vero cell monolayer also maintained the viability percentage of these sperm samples (52% of the original value) after the 24-h period compared with culture in HTF medium alone (22% of the original) (52% versus 22%, P < 0.05). It is concluded that Vero cell monolayer is effective in the maintenance of motility and viability of asthenozoospermic semen or frozen-thawed semen with poor motility. This co-culture system may be beneficial in enhancing the in-vitro performance of asthenozoospermic semen samples in the practice of assisted reproductive technology. However, its safety needs further evaluation.

Animals↗
PubMed1994

Age, environment, and lymphocyte immunization influence the spontaneous resorption rate in the CBA/J x DBA/2J mouse model.

PROBLEM: This study was designed to examine the influence of age, environment, and lymphocyte immunotherapy on fetal resorption rates in the CBA/J x DBA/2J mouse model. METHODS: After weaning, CBA/J female mice were randomly allocated to two different environments: room A was a conventional housing facility, and room B was a specific pathogen-free room. They were further divided into two groups in each room according to age (> three months and < or = three months), and mated with CBA/J, DBA/2J, or BALB/c males. The fetal resorption rates were observed. The immunization study was conducted using CBA/J females greater than three months old in room B. Preimmunization with various preparations and dosages of lymphocytes was performed 1 wk before mating with DBA/2J males, and fetal resorption rates were measured to investigate the effect of immunotherapy. RESULTS: In room A, the fetal resorption rates (9.4 to 11.8%) were not significantly different among the various mating combinations using CBA/J females greater or less than three months of age. In room B, CBA/J females older than three months and mated with DBA/2J males had a higher rate of fetal resorption than those younger than three months (28.9 versus 14.2%) and had higher rate of fetal resorption than those housed and mated in room A (28.9 versus 10.9%). This fetal resorption rate was also higher than those seen with other mating combinations. Preimmunization with male BALB/c splenic lymphocytes (optimal dose 1 x 10(7) cells) was effective in decreasing fetal resorption rate (7.9%), whereas administration of normal saline, or immunization with male CBA/J or DBA/2J lymphocytes was not (20.7 to 27.0%). CONCLUSION: Age and environment influence the spontaneous resorption rate in the CBA/J x DBA/2J mouse model. The high fetal resorption rate of older CBA/J females mated with DBA/2J males in a pathogen-free environment can be reduced by immunization with BALB/c splenic lymphocytes. These results suggested that a variety of mechanisms might initiate early pregnancy failure and that immunological modulation during implantation might be a nonspecific factor.

Abortion, Spontaneous↗
PubMed1993

Analysis of human in vitro fertilization failure.

Fertilization failure is a serious problem in human in vitro fertilization (IVF) programs and deserves further investigation and management. Two hundred and ninety-four IVF cycles performed at the National Taiwan University Hospital from July 1989 to June 1991 were retrospectively analyzed. Thirty-seven (13%) of the 294 cycles were observed to have fertilization failure. The incidence of fertilization failure in male factor patients was significantly higher (p < 0.05) than in others. Patients with oligoasthenospermia tended to have a higher rate of fertilization failure than patients with oligospermia or asthenospermia alone. In non-male factor patients, a smaller number of oocytes and mature oocytes was found in patients with fertilization failure than in patients achieving fertilization. Sperm penetration assay (SPA) using zona-free hamster eggs was performed for 15 patients with fertilization failure; no correlation was found between SPA and the fertilizing ability of the sperm in vitro. Four patients with severe oligoasthenospermia had repeated fertilization failure in subsequent IVF cycles. The other five patients, including four non-male factor patients and one male factor patient, achieved fertilization in their second IVF trial. Our results suggest that severe oligoasthenospermic patients with repeated fertilization failure should be candidates for micromanipulation of gametes in subsequent IVF trials.

Female↗
PubMed1992

Effect of the number and depth of embryos transferred and unilateral or bilateral transfer in tubal embryo transfer (TET).

PURPOSE: Our purpose was to evaluate the possible effects of the number of embryos transferred, the depth of embryos placed within the tube(s), and unilateral or bilateral tubal transfer on pregnancy initiation in tubal embryo transfer (TET). METHODS: One hundred eight consecutive TET cycles were analyzed. Oocyte retrievals were carried out by transvaginal ultrasound-guided aspiration of follicles. Forty-eight hours after oocyte retrieval, the developing embryos at the stage of two to four cells were transferred into the fallopian tube(s) by laparoscopy. A maximum of four embryos was transferred to each patient. RESULTS: The pregnancy rates were similar among the cycles in which two, three, or four embryos were transferred. In addition, there was no significant difference in the pregnancy rate whether the embryos were deposited > 4 cm or between 3 and 4 cm into the tube(s). Although the pregnancy rate was greater in cycles of bilateral tubal transfer, the difference from that of unilateral transfers was not significant. CONCLUSION: Our data indicate that when two to four embryos were transferred and the embryos were placed > or = 3 cm within the tube(s), unilateral or bilateral tubal transfer had little influence on the ultimate success of TET.

Embryo Transfer↗
PubMed1992

Combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization and embryo transfer: report of a case.

A case of combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization (IVF) and transfer of six embryos is presented. The case was diagnosed as intrauterine triplets ultrasonographically at seven weeks of gestation. Unfortunately, the patient suffered from severe lower abdominal pain and hypovolemic shock at 10 weeks of gestation, and an emergent laparotomy was done. During the operation, a ruptured cornual pregnancy with accompanying hemoperitoneum was found. Because fetal heart beats were not detected by intraoperative ultrasonography in the other two intrauterine fetuses, evacuation of the gestational contents through the uterine defect was done, and the rupture site was repaired. The incidence, mechanism and management of heterotopic pregnancies after in vitro fertilization and embryo transfer are discussed.

Adult↗
PubMed1990

Inhibition of monoamine oxidase by 7-chloro-4-nitrobenzofurazan.

7-Chloro-4-nitrobenzofurazan (NBD-Cl) is a potent inhibitor of both types of monoamine oxidase (MAO). NBD-Cl competitively inhibited the oxidative deamination of kynuramine catalyzed by human placenta MAO-A, the oxidative deamination of benzylamine catalyzed by bovine liver MAO-B, the oxidative deamination of serotonin catalyzed by rat brain MAO-A, and the oxidative deamination of phenylethylamine catalyzed by rat brain MAO-B. In addition, a time-dependent inactivation of MAOs by NBD-Cl has been demonstrated upon incubation of the enzyme preparations with NBD-Cl at pH 9, but not at pH 7.5. The time-dependent inhibition of MAO by NBD-Cl could be prevented by the addition of 4-nitrophenyl azide, an active site-directed label of MAO, during incubation of the enzyme with NBD-Cl. On the basis of these findings, it is suggested that at pH 9, NBD-Cl modifies one (or more) essential lysine residue(s) in the active sites of the two types of MAO.

Animals↗
PubMedDate not supplied

Schedule to inject in vitro matured oocytes may increase pregnancy after intracytoplasmic sperm injection.

To ascertain the value of using immature oocytes in an intracytoplasmic sperm injection (ICSI) program, the authors designed a schedule, at 5 p.m. on day 1 (the day of oocyte retrieval) and at 8 a.m. and 2 p.m. on day 2, to recognize and inject the in vitro matured (IVM) oocytes. For the 1,166 oocytes retrieved in 107 ICSI cycles, 128 (11.0%) were at the stage of metaphase I (MI) and 113 (9.7%) at germinal vesicle. Routine ICSI for metaphase 11 oocytes was performed at 2 p.m. on day 1 (initial ICSI). In culture medium of human tubal fluid with 15% maternal serum, 85.1% (205/241) immature oocytes progressed to maturation in which 16.4% (21/128) of MI oocytes matured at 5 p.m. of day 1. The rate of normal fertilization for IVM oocytes (58.5%) was not significantly different from that of initial ICSI (64.0%). One patient received a transfer of two fertilized IVM oocytes alone that were injected at 5 p.m. of day 1, maturing from the MI stage, and achieved a normal pregnancy. The fertilized IVM oocytes were replaced along with the embryos from initial ICSI for 40 cycles that led to 14 (35%) clinical pregnancies. In 43 fertilized IVM oocytes donated for research, we observed that cleavage (95.3%) to the 2- to 4-cell stage was not distinct from that of initial ICSI (94.6%); however, the percentage of embryos of grade I and II morphology was significantly smaller (24.4% vs. 62.5%). Only five (11.6%) developed to blastocysts in vitro. Twenty-one fertilized IVM oocytes were frozen for future transfer. A schedule to inject IVM oocytes in ICSI cycles may generate more accessible embryos for fresh transfer or cryopreservation to increase the chance of pregnancy, although the embryo quality was relatively poor.

Adult↗
PubMedDate not supplied

Microinjection of human sperm into perivitelline space of hamster eggs: comparison with zona-free hamster egg penetration of human sperm.

Micromanipulation of human sperm and oocyte has been utilized to facilitate fertilization of those patients with male factor due to oligoasthenospermia or those patients with repeated fertilization failure in an in vitro fertilization (IVF) program. Before manipulating human gametes, one needs experience with animal models. Our objective was to perform subzonal insertion of human sperm into hamster eggs and to compare the result with that of sperm penetration assay (SPA) using zona-free hamster eggs. Semen samples were obtained from 15 fertile donors with normal semen analysis and the motile sperm were collected by swim-up procedure. Microinjection was performed by injecting a varied number of sperm into the perivitelline space of 222 hamster eggs pretreated with sucrose solution (0.1 M). The rate of damage of eggs during microinjection was 7.2% (16/222). The rates of penetration in the microinjection group were 5.1% (4/79) for 1-5 sperm injected, 10.9% (11/101) for 6-10 sperm injected, and 11.5% (3/26) for 11-15 sperm injected. The average rate of penetration per egg was 8.7% (18/206), and the polyspermic rate was 11.1% (2/18). Simultaneously SPA was performed in each sample of semen as a positive control, and the average rate of penetration of SPA was 51.4% (108/210). The rate of penetration in the microinjection group was significantly smaller (p < .05) than that in the SPA group. Whether the penetration rate and polyspermic rate in a hamster model reflect similar results in human oocyte requires further investigation. However, the hamster egg provides an ideal model to develop a micromanipulation technique for human beings.

Animals↗