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Biomedical subjects

C R Tzeng

Publications and source records attributed to C R Tzeng.

At least 19 recordsLinked to original sources
PubMed2004

Assessment of changes in utero-ovarian arterial impedance during the peri-implantation period by Doppler sonography in women undergoing assisted reproduction.

OBJECTIVE: To investigate changes in utero-ovarian blood flow during the peri-implantation period and their significance in successful embryo implantation. METHODS: A prospective longitudinal study was conducted in 317 women undergoing in-vitro fertilization-embryo transfer (IVF-ET) treatment. All of them had at least one good-quality embryo for transfer on the second or third day after oocyte retrieval. Measurement of endometrial thickness and color flow imaging with pulsed waveform analysis of uterine and ovarian arteries were performed before ET and 5-6 days after ET. RESULTS: There were no significant differences in the age of patients, duration of infertility or number of embryos transferred between women who became pregnant (n = 91) and those who did not (n = 226). There was no difference in mean endometrial thickness between the two groups before ET, while a thicker endometrium was found in women who had conceived compared with those who had not 5-6 days after ET (P = 0.02). Mean uterine arterial resistance index (RI) and pulsatility index (PI) values were significantly lower in the pregnant than in the non-pregnant group before ET (P = 0.04 and P = 0.003, respectively), but no significant differences were found between the two groups 5-6 days after ET. In contrast, the mean ovarian arterial RI and PI values were similar between the two groups before ET, yet the pregnant group showed significantly lower RI and PI values compared with the non-pregnant group 5-6 days after ET (P = 0.002 and P = 0.01, respectively). A significantly higher peak systolic velocity (PSV) of intraovarian vessels was also noted in the pregnant group 5-6 days after ET. CONCLUSION: Different utero-ovarian blood flow changes during the peri-implantation period occur in conception and non-conception cycles in women following IVF. Doppler assessment of uterine arterial resistance can help to determine a time interval within the menstrual cycle that is of optimal endometrial status for embryo implantation in assisted conception programs. Delay in achieving adequate uterine perfusion during the temporal window of embryo implantation may have an impact on endometrial receptivity.

Adult↗
PubMed2002

The hyperaggregability of platelets from normal pregnancy is mediated through thromboxane A2 and cyclic AMP pathways.

There is substantial evidence of increased platelet reactivity in vivo and in vitro during pregnancy, with the risk of developing pre-eclampsia. In this study, platelet function was studied during 28-40 weeks of gestation in a group of women who remained normotensive and in a group of nonpregnant female controls. Platelet aggregation stimulated by thrombin and adenosine diphosphate was markedly enhanced in washed platelets from pregnant subjects. Thrombin (0.04 U/ml)-evoked increases in intracellular Ca+2 mobilization of Fura 2-AM-loaded platelets were also enhanced in pregnant subjects. The binding of fluorescein isothiocyanate (FITC)-triflavin (2 microg/ml) to the glycoprotein IIb/IIIa complex in thrombin-activated platelets did not differ significantly between the nonpregnant and pregnant groups. Thromboxane A2 (TXA2) formation in both resting and thrombin-activated platelets from pregnant subjects was significantly greater than from nonpregnant subjects. Levels of cyclic adenosine monophosphate (cAMP) in both resting and prostaglandin E1-treated platelets (10 micromol/l) from pregnant subjects were significantly lower than those from nonpregnant subjects. There were no significant differences between nonpregnant and pregnant subjects in platelet cAMP levels in the presence of imidazole (600 micromol/l) and indomethacin (500 micromol/l). Intracellular pH values in platelets were measured spectrofluorometrically using the fluorescent probe, BCECF-AM. The increase in intracellular pH stimulated by thrombin (0.04 U/ml) in pregnant subjects was markedly greater than that in observed nonpregnant subjects. We conclude that the agonist-induced hyperaggregability of platelets in normal pregnancy may be due, at least partly, to stimulation of the Na+/H+ exchanger and subsequently to elevated intracellular Ca+2 mobilization, and then to increased TXA2 formation and a lowered level of cAMP, which leads to further increases in intracellular Ca+2 mobilization, and finally to enhanced platelet aggregation.

Adult↗
PubMed2001

Herniated blastomere following chemically assisted hatching may result in monozygotic twins.

OBJECTIVE: To explore a possible mechanism of the increasing incidence of monozygotic twins following assisted hatching of human embryos. DESIGN: Case report. SETTING: Clinical research center in a medical school teaching hospital. PATIENT: A 37-year-old infertile woman with repeated IVF failures. INTERVENTION(S): Assisted hatching of the day 3 embryos using acidic Tyrode's solution. MAIN OUTCOME MEASURE(S): The morphology of the zona-drilled embryos and the pregnancy outcome. RESULT(S): After assisted hatching, a herniated blastomere through an oversized opening in the zona pellucida was found in one embryo. The transfer of two zona-drilled embryos resulted in a triplet pregnancy. CONCLUSION(S): Large openings in the zona pellucida following chemically assisted hatching may cause premature hatching of the blastomeres and may be implicated in the occurrence of monozygotic twins.

Adult↗
PubMed2001

Nitric oxide as a regulator in preimplantation embryo development and apoptosis.

OBJECTIVE: To investigate the mechanisms of nitric oxide (NO) in the development and apoptosis of preimplantation mouse embryos. DESIGN: Prospective, controlled study. SETTING: Medical college laboratory. SUBJECT(S): Two-cell embryos from outbred ICR mice. INTERVENTION(S): Hyperstimulation protocol, two-cell embryos were collected, then treated with or without an NO synthase inhibitor (L-NAME) or an NO donor (SNP) and combined with a cGMP analogue (8-Br-cGMP) or a selective inhibitor of NO-sensitive soluble guanylyl cyclase (ODQ). MAIN OUTCOME MEASURE(S): The development of ICR mouse embryo from two cells to blastocyst stages in vitro. RESULT(S): The development of blastocyst was inhibited by L-NAME in a concentration-dependent manner (0.1-10 microM) and 0.1 microM SNP reversed this effect (80.5% of control). Annexin-V/propidium iodide and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling techniques demonstrated that excessive NO (> or =10 microM) might induce apoptosis in the mouse embryos. 8-Br-cGMP reversed the inhibitory effect of L-NAME and rescued the embryo growth. ODQ inhibited the embryo development in a dose-responsive fashion (0.1--100 microM) but had no effect in the NO-induced embryo apoptosis. P53 and Bax were found to be up-regulated during the embryo fragmentation. CONCLUSION(S): These results indicate that the cGMP pathway might be involved in the NO-regulated embryonic development, but not in NO-induced apoptosis, for which P53/Bax pathway might be involved.

Animals↗
PubMed2001

Adenosine triphosphate activates mitogen-activated protein kinase in human granulosa-luteal cells.

ATP has been shown to activate the phospholipase C/diacylglycerol/protein kinase C (PKC) pathway. However, little is known about the downstream signaling events. The present study was designed to examine the effect of ATP on activation of the mitogen-activated protein kinase (MAPK) signaling pathway and its physiological role in human granulosa-luteal cells. Western blot analysis, using a monoclonal antibody that detected the phosphorylated forms of extracellular signal-regulated kinase-1 and -2 (p42(mapk) and p44 (mapk), respectively), demonstrated that ATP activated MAPK in a dose- and time-dependent manner. Treatment of the cells with suramin (a P2 purinoceptor antagonist), neomycin (a phospholipase C inhibitor), staurosporin (a PKC inhibitor), or PD98059 (an MAPK/ERK kinase inhibitor) significantly attenuated the ATP-induced activation of MAPK. In contrast, ATP-induced MAPK activation was not significantly affected by pertussis toxin (a G(i) inhibitor). To examine the role of G(s) protein, the intracellular cAMP level was determined after treatment with ATP or hCG. No significant elevation of intracellular cAMP was noted after ATP treatment. To determine the role of MAPK in steroidogenesis, human granulosa-luteal cells were treated with ATP, hCG, or ATP plus hCG in the presence or absence of PD98059. RIA revealed that ATP alone did not significantly affect the basal progesterone concentration. However, hCG-induced progesterone production was reduced by ATP treatment. PD98059 reversed the inhibitory effect of ATP on hCG-induced progesterone production. To our knowledge, this is the first demonstration of ATP-induced activation of the MAPK signaling pathway in the human ovary. These results support the idea that the MAPK signaling pathway is involved in mediating ATP actions in the human ovary.

Adenosine Triphosphate↗
PubMed2001

Role of mitogen-activated protein kinase in prostaglandin f(2alpha) action in human granulosa-luteal cells.

In the ovary it has been demonstrated that PGF(2alpha) activates the phospholipase C (PLC)/diacylglycerol/protein kinase C pathway. However, little is known about the downstream signaling events that mediate subsequent cellular responses such as steroidogenesis. The present study was designed to examine the effect of PGF(2alpha) on activation of the mitogen-activated protein kinase (MAPK) signaling pathway and its physiological role in human granulosa-luteal cells (hGLCs). Human GLCs, obtained from women undergoing in vitro fertilization-embryo transfer, were treated with increasing concentrations of PGF(2alpha) (10 nmol/L to 10 micromol/L) for 5 min. For time-course experiments, hGLCs were treated with 1 micromol/L PGF(2alpha) for 1, 5, 10, or 20 min. Western blot analysis, using a monoclonal antibody that detected the phosphorylated forms of extracellular signal-regulated kinases 1 and 2 (p42(mapk) and p44(mapk), respectively), demonstrated that PGF(2alpha) activated MAPK in hGLCs in a dose- and time-dependent manner. Treatment of the cells with neomycin (10 mmol/L; a PLC inhibitor), bisindolylmaleimide I (5 micromol/L; a PKC inhibitor), or PD98059 (50 micromol/L; a MEK inhibitor and a MAPK kinase inhibitor) significantly attenuated the PGF(2alpha)-induced activation of MAPK. In contrast, MAPK activation was not significantly affected by pertussis toxin (200 ng/mL; a G(i) inhibitor) pretreatment. To determine the role of MAPK in steroidogenesis, hGLCs were treated with PGF(2alpha) (1 micromol/L), hCG (1 IU/mL), or PGF(2alpha) plus hCG in the presence or absence of PD98059. Progesterone levels in the culture medium were examined by RIA. Treatment of hGLCs with PGF(2alpha) significantly inhibited hCG-induced progesterone production. The presence of the MEK inhibitor, PD98059, reversed the inhibitory effect of PGF(2alpha) on hCG-induced progesterone production. To our knowledge, it is the first demonstration of PGF(2alpha)-induced activation of the MAPK signaling pathway in the human ovary. These results indicated that PGF(2alpha) activated MAPK subsequent to PLC and PKC activation through pertussis toxin-insensitive G protein in hGLCs. Further, we demonstrated that PGF(2alpha)-induced MAPK activation is associated with modulation of progesterone production. These results support the idea that the MAPK signaling pathway is involved in mediating PGF(2alpha) actions in the human ovary.

Cells, Cultured↗
PubMed2001

Antigonadotropic action of adenosine triphosphate in human granulosa-luteal cells: involvement of protein kinase Calpha.

The presence of P2U purinoceptor in human granulosa-luteal cells (hGLCs) indicates a potential role of ATP in regulating ovarian function. In this study an inhibitory effect of ATP on hCG-induced cAMP production was observed. Extracellular ATP has been shown to activate protein kinase C (PKC) after binding to a purinoceptor. To understand the role of PKC in mediating ATP action, hCG-stimulated cAMP level was examined in the presence of the PKC activator, 1 micromol/L phorbol 12-myristate 13-acetate (PMA), or the PKC inhibitor, 1 micromol/L staurosporin or 1 micromol/L bisindolylmaleimide I. PMA, like 10 micromol/L ATP, significantly reduced hCG-evoked cAMP production. In addition, the inhibitory effect of ATP was reversed by staurosporin and bisindolylmaleimide I. To further investigate the involvement of PKC isoforms in mediating the inhibitory effect of ATP, the presence of PKC isoforms in cultured hGLCs was examined by Western blot using monoclonal antibodies against specific isoforms. Translocation of PKC isoforms from cytosolic fraction to membrane fraction was studied to identify the active PKC isozymes subsequent to ATP treatment. The change in PKC isoform in PKC-depleted cells (achieved by exposure to PMA for 18 h) was also examined. Our results demonstrated the presence of PKCalpha, -delta, -iota, and -lambda isoforms in hGLCs and the translocation of PKCalpha subsequent to ATP treatment. In PKC-depleted cells the PKCalpha level was reduced, and no significant effect of ATP on hCG-stimulated cAMP production was observed. To our knowledge, this is the first demonstration of PKC isoforms in hGLCs and the involvement of activated PKC in mediating the antigonadotropic effect of extracellular ATP. Taken together, these results further support a role of this neurotransmitter in regulating human ovarian function.

Adenosine Triphosphate↗
PubMed2000

Postoperative coma induced by hyponatremia after laparoscopy--a case report.

Hyponatremia is a common clinical entity which may occur during the course of many medical illnesses. However disastrous sequelae or even death may develop in young, generally healthy patients who receive simple elective surgery. Here we present a case of a 34-year-old female, without past history of cardiopulmonary or renal disease, after undergoing laparoscopic surgery developed mental status changes and lapsed into coma on the second postoperative day. She was found to have a serum sodium level of 110 mEq/L. After careful treatment and a protracted hospital stay, the patient recovered uneventfully. The pathophysiology of postoperative hyponatremia is discussed and attention is called to the special vulnerability of menstruant women who carry a much increased risk of mortality and morbidity associated with hyponatremia.

Adult↗
PubMed1999

Sonographically guided intralesional antibiotic injection for treatment of a recalcitrant pelvic abscess: a case report.

A pelvic abscess occurred in an infertile woman with an endocervical gonococcal infection after hysterosalpingographical examination. The pelvic abscess was not cured despite rigorous antimicrobial chemotherapy until two intra-abscess ceftriaxone injections were administered. This shows that antibiotics administered systemically may not reach therapeutic concentration in an abscess and an intra-abscess antibiotic injection may help to cure it.

Abscess↗
PubMed1998

Sperm head agglutination induced by V3 peptide does not occur through a CD4 receptor.

BACKGROUND: Although recent studies have shown that HIV (human immunodeficiency virus) can attach to sperm, the mechanism by which it does this is not yet understood. It has been shown that CD4 receptors on T4 cells are responsible for the binding of gp120 (glycoprotein 120) to HIV; however, the existence of CD4 receptors on sperm is controversial. The V3 peptide is part of gp120 and crucial for the syncytium formation by CD4 receptors. In this study we used an anti-CD4 antibody to block V3 peptide-induced sperm head agglutination in an attempt to gain a further understanding of the mechanism of HIV attachment to sperm. METHODS: Ten semen samples from 10 healthy men were studied. A sperm head fixation method (SHFM) was used to evaluate the blocking effect of anti-CD4 antibody (Q4120) of V3 peptide-induced sperm head agglutination in phosphate-buffered saline solution. RESULTS: While the sperm swam out of the micropipette, as occurs in SHFM, the V3 peptide induced an average of 53.2 +/- 10.8 (mean +/- SEM) head-to-head bound sperm (in the 10 semen samples. The sperm that had been preincubated with anti-CD4 antibody induced an average of 54.1 +/- 11.6 head-to-head bound sperm. There was no significant difference found between sperm that had been preincubated or not preincubated with anti-CD4 antibody, in terms of sperm head agglutination. CONCLUSIONS: The anti-CD4 antibody can block the binding of gp120 and CD4 positive T cells in a low concentration, but it did not block V3 peptide-induced sperm head agglutination. Therefore, V3 peptide-induced sperm head agglutination may not occur through a CD4 receptor.

Agglutination↗
PubMed1998

Surgical and pathologic observations of epididymal tubules during microscopic epididymal sperm aspiration for intracytoplasmic sperm injection.

Microscopic epididymal sperm aspiration (MESA) for sperm retrieval and intracytoplasmic sperm injection (ICSI) is currently our routine treatment for selected male patients with obstructive azoospermia. In order to refine the surgical technique and obtain better quality sperm for our assisted reproductive technology program, we observed the epididymal tubules in 40 sessions of surgical exploration of the epididymis for sperm aspiration. Epididymal tubules with long-term obstruction could be divided into three groups on the basis of clinical observations and pathology findings: markedly dilated, mildly dilated, and nondilated. All of the markedly dilated epididymal tubules (grade III, n = 10) were azoospermic and ICSI could not be done. Epididymal sperm obtained from the mildly dilated tubules (grade II, n = 9) resulted in poorer fertilization (49%) and pregnancy (33%) rates than sperm obtained from nondilated epididymal tubules (grade I, n = 21, fertilization rate 72%, pregnancy rate 57%). These findings demonstrate that nondilated epididymal tubules are best for sperm retrieval and successful ICSI. We believe this observation will be a good surgical parameter for urologic surgeons performing MESA.

Epididymis↗
PubMed1996

Pregnancy following in vitro fertilization and embryo transfer by microsurgical epididymal sperm aspiration from a patient with congenital absence of the vas deferens: a case report.

Congenital absence of the vas deferens (CAVD) has been considered a virtually untreatable cause of male infertility. Men with this condition have been shown on testicular biopsy to have adequate spermatogenesis, and are theoretically producing sperm capable of fertilizing an oocyte. Yet epididymal transit was thought to be essential for the maturation of spermatozoa and development of their fertilizing ability since the characteristics of sperm motility improve as the sperm passes through the cauda. However recent studies in man have shown that spermatozoa aspirated from the obstructed caput epididymis and ductuli efferentia are, in fact, capable of fertilization in vitro. Microsurgical epididymal sperm aspiration (MESA) from the proximal region (caput) of the epididymis, obtained 0.5 x 10(6) sperm per ml, following washing and direct swim-up. Twelve oocytes were inseminated and three embryos were generated for transfer. The patient conceived and delivered a healthy female baby weighting 2838 gm, on March 3, 1994. This is the first documentation in Taiwan of live birth resulting from MESA from a patient with CAVD combined with in vitro fertilization and embryo transfer.

Adult↗
PubMed1995

The correlation of the embryo implantation rate with uterine arterial impedance in in vitro fertilization and embryo transfer.

The influence of uterine blood flow impedance on embryo implantation rate was investigated by transvaginal color Doppler sonography examination before embryo transfer. A total of 108 women undergoing in vitro fertilization (IVF) procedures and who had at least one good quality embryo for transfer to the uterus received Doppler evaluation before embryo transfer. Color flow imaging with blood flow waveform analysis from bilateral uterine arteries was obtained to calculate the mean pulsatility index (PI). The correlations between mean PI with the pregnancy rate and the embryo implantation rate (number of embryos implanted/number of embryos transferred) were analyzed. Patients were grouped according to the mean PI value, and the pregnancy rate and embryo implantation rate were 25% (5/20) and 10.7% (9/84), respectively, with a PI < 2.0 (n = 20); 27.5% (14/51) and 12.2% (12/109), respectively, with a PI = 2.00-2.49 (n = 51); 9.5% (2/21) and 3.5% (2/57), respectively, with a PI = 2.50-2.99 (n = 21); and 6.3% (1/16) and 4.3% (2/47), respectively, with a PI [symbol: see text] 3.0 (n = 16). There were no significant differences in either pregnancy rate or embryo implantation rate between the groups with mean PI values less than 2.00 and between 2.00 and 2.49. If a mean PI value of 2.50 was used as the cut-off value, both the pregnancy rate and embryo implantation rate were significantly higher in patients with a mean PI less than 2.50 (p < 0.05). The uterine arterial impedance measured by the Doppler sonographic examination is a non-invasive method for evaluating the endometrial response and a mean uterine PI value of 2.5 can be used as a cut-off value to identify optimal uterine receptivity before embryo transfer.

Adult↗
PubMed1994

Effect of peritoneal fluid and serum from patients with endometriosis on mouse embryo in vitro development.

BACKGROUND: The adverse effects on early embryo development as caused by peritoneal fluid exudate and serum from endometriosis patients have been shown, but the underlying mechanism and clinical significance remain unknown. METHODS: Peritoneal fluid (PF) and serum (S) from patients with minimal to mild endometriosis (Group A, n = 12), moderate to severe endometriosis (Group B, n = 6), and others including tubal ligation and uterine myoma (Group C, controls n = 6) were obtained during laparoscopy. Two-cell mouse embryos were cultured at 37 degrees C in 5% CO2, 95% air with supplementation of 10%PF + 1%BSA, 10%S and 10%S + 10%PF in HTF medium. The percentage of progression to the blastocyst stage at 72 and 96 hours was observed and compared among the three groups. RESULTS: Serum and peritoneal fluid from infertile patients with moderate to severe endometriosis appeared to be embryotoxic to the in vitro development of two-cell mouse embryos, but no significant differences were found between minimal to mild endometriosis and group C patients. CONCLUSIONS: These data suggest that the production of embryotoxic factor(s) is related to the clinical stage, and may be derived from endometriotic implants. The correlation of the embryotoxic effect of the peritoneal fluid with that of the serum indicates that embryotoxic factor(s) may enter the systemic circulation and impede early embryogenesis in the reproductive tract. The nature and mechanism of this result demand further study.

Animals↗
PubMed1991

Buserelin treatment of endometriosis in Chinese women.

Twenty five patients with endometriosis of varying degree had been treated with Buserelin (GnRH analogue) for 6 months. Among them, 83.4% reached castrated level by measuring the serum estradiol (E2) 2 months after therapy. Dysmenorrhea was alleviated or completely disappeared during therapy. Hot flush was the one mostly complained. Vaginal dryness was the second and decreased libido the third. Persisted periodic bleeding was noted in 3 patients. Ovulation was suppressed as evidenced by low serum progesterone throughout the whole course of treatment. Second-look laparoscopy was done at the end of 6-month therapy. Scoring assigned by the American Fertility Society (AFS) was reduced by 27.5%. The adrenal gland, liver and renal functions as well serum calcium and phosphate were retained at the end of treatment. Ovulation and menstruation also returned to normal within 2 months after cessation of therapy. There were 4 pregnancies during the 6-month follow period (4/15 = 26.6% pregnancy rate). 7 patients had improved symptoms whereas 7 patients sustained recurrent dysmenorrhea. The hormonal profile showed that dysmenorrhea improved group had better ovarian suppression than the dysmenorrhea recurrent group.

Adult↗