Peter L. Chang

Syk Tyrosine Kinase Is Required for Immunoreceptor Tyrosine Activation Motif-dependent Actin Assembly

Clustering of several multisubunit receptors on hematopoetic cells results in a signaling cascade involving the phosphorylation of immunoreceptor tyrosine activation motifs, or “ITAMs,” and actin polymerization. Recent experiments indicate that direct clustering of the ITAM-binding protein, p72syk (Syk), is capable of transmitting a phagocytic signal in COS cells (Greenberg, S., Chang, P., Wang, D., Xavier, R., and Seed, B. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 1103-1107). However, the possibility of redundant signaling pathways makes it difficult to test the requirement for Syk in ITAM-dependent actin polymerization in hematopoetic cells. We developed a model system to study ITAM-dependent actin assembly. DT40 lymphocytes were transfected with fusion proteins encoding the transmembrane and cytosolic domains of the ITAM-containing γ subunit of Fc receptors. Clustering the γ-containing fusion proteins with IgG-coated erythrocytes triggered submembranous actin assembly. This response depended on an intact ITAM, was absent in cell lines that had been engineered to lack Syk, and was augmented in cell lines that stably overexpressed Syk. These experiments demonstrate an absolute requirement for Syk tyrosine kinase in ITAM-dependent actin assembly in transfected lymphocytes.

Recombinant human chorionic gonadotropin (rhCG) in assisted reproductive technology: results of a clinical trial comparing two doses of rhCG (OvidrelR) to urinary hCG (ProfasiR) for induction of final follicular maturation in in vitro fertilization–embryo transfer

OBJECTIVEnTo compare the efficacy and safety of 250 microg and 500 microg of recombinant hCG with 10,000 U USP of urinary hCG in assisted reproduction technology.nnnDESIGNnOpen, comparative, randomized, prospective clinical study.nnnSETTINGnTwenty tertiary care U.S. infertility centers.nnnPATIENT(S)nTwo hundred ninety-seven ovulatory infertile women undergoing a single cycle of assisted reproduction technology.nnnINTERVENTION(S)nPatients were randomized 1:1:1 to 250 microg of recombinant hCG SC, 500 microg of recombinant hCG SC, or 10,000 U USP urinary hCG IM after completing gonadotropin stimulation.nnnMAIN OUTCOME MEASURE(S)nNumber of oocytes retrieved per patient receiving hCG. Also, measures of oocyte maturity, embryo development, and luteal function, as well as pregnancy and pregnancy outcome. Adverse safety events, laboratory changes, local tolerance, and immunogenicity were also assessed.nnnRESULT(S)nMean numbers of oocytes retrieved per treatment group were equivalent, 13.6, 14.6, and 13.7 with 250 microg of recombinant hCG, 500 microg of recombinant hCG, and urinary hCG, respectively. The numbers of 2PN fertilized oocytes on day 1 after oocyte retrieval, and 2PN or cleaved embryos on the day of embryo transfer, were significantly higher with 500 microg of recombinant hCG than with the lower dose. However, the incidence of adverse events also tended to be higher with this dose.nnnCONCLUSION(S)nRecombinant hCG is effective and well tolerated in the induction of final follicular maturation and luteinization in women undergoing assisted reproduction technology. Recombinant hCG (250 microg) SC is equivalent to 10,000 U USP of urinary hCG in this indication.

Circulating leptin levels during ovulation induction : relation to adiposity and ovarian morphology

OBJECTIVEnTo assess serum leptin levels based on body habitus and ovarian morphology during controlled ovarian hyperstimulation.nnnDESIGNnProspective analysis.nnnSETTINGnUniversity IVF program.nnnPATIENT(S)nWomen undergoing IVF-ET were divided into two groups, obese ovulatory women (n = 6; mean (+/-SD) body mass index, 30.1 +/- 0.6 kg/m(2)) and lean ovulatory women (n = 20); mean (+/- SD) body mass index 22.0 +/- 0.2 kg/m(2)). Lean women were categorized further according to whether they had polycystic-appearing ovaries (n = 8) or normal-appearing ovaries (n = 12).nnnINTERVENTION(S)nControlled ovarian hyperstimulation and IVF.nnnMAIN OUTCOME MEASURE(S)nSerum estradiol, testosterone, and leptin.nnnRESULT(S)nMean (+/- SD) leptin levels were significantly higher before and after GnRH agonist down-regulation in obese women (41.7 +/- 5.2 pg/mL and 36.1 +/- 5.8 pg/mL, respectively) compared with lean women (8.4 +/- 1.0 pg/mL and 6.9 +/- 1.1 pg/mL, respectively). Mean (+/- SD) leptin levels increased significantly in both groups (54.5 +/- 5.1 pg/mL and 11.7 +/- 1.2 pg/mL, respectively), and the mean (+/-SD) percentage increase was similar (55% +/- 18% and 54.8% +/- 17%, respectively). Mean (+/-SD) leptin levels were similar in women with polycystic-appearing and normal-appearing ovaries before controlled ovarian hyperstimulation, but increased significantly in women with polycystic-appearing ovaries afterward (14.7 +/- 1.8 pg/mL and 9.3 +/- 1.0 pg/mL, respectively).nnnCONCLUSION(S)nSignificant increases in leptin levels occur during controlled ovarian hyperstimulation, suggesting that leptin plays a role in follicular growth and maturation. The exaggerated response in women with polycystic-appearing ovaries reflects either a greater number of recruited follicles or a predisposition of adipocytes to leptin production.

Serum Progesterone Before and After Human Chorionic Gonadotropin Injection Depends on the Estradiol Response to Ovarian Hyperstimulation During In Vitro Fertilization–Embryo Transfer Cycles

Purpose:Our purpose was to assess if periovulatory serum progesterone is reflective of ovarian responsiveness in controlled ovarian hyperstimulation (COH).Methods:One-hundred forty-two in vitro fertilization–embryo transfer cycles in women using GnRH-a suppression and human menopausal gonadotropin (hMG) stimulation were evaluated. Responses were studied according to ovarian response to hMG and age. Outcome measures included peak serum estradiol, serum progesterone and estrogen/progesterone ratios on the day of hCG injection, number of harvested oocytes, fertilization rates, and delivered pregnancy rates.Results:A periovulatory rise in serum progesterone (>0.9 ng/ml) occurred only among younger women (<40 years old) with a good response (P<0.05). Though the number of oocytes was greater in good responders, fertilization and pregnancy rates were similar among all women regardless of age and ovarian response.Conclusions:Periovulatory levels of serum progesterone vary according to ovarian response to COH. Elevations in progesterone do not appear to be a manifestation of poor responders. Reduced periovulatory progesterone may reflect inadequate steroidogenesis.

Successive pregnancies with delivery of two healthy infants in a couple who was discordant for human immunodeficiency virus infection

OBJECTIVEnTo describe two successive pregnancies resulting in two healthy infants in an HIV-discordant couple who underwent IVF-ICSI.nnnDESIGNnCase report.nnnSETTINGnUniversity-based infertility clinic.nnnPATIENT(S)nA couple seeking fertility treatment in which the male partner was seropositive for HIV-1.nnnINTERVENTION(S)nControlled ovarian hyperstimulation and IVF-ET with ICSI.nnnMAIN OUTCOME MEASURE(S)nPregnancy outcome and HIV-1 seroconversion.nnnRESULT(S)nThe couple delivered two healthy infants on successive pregnancies with use of IVF-ET with ICSI.nnnCONCLUSION(S)nFor HIV-discordant couples in which the male partner is seropositive for HIV-1, IVF with ICSI is a viable option.

Galactosyl receptor, a cell surface C-type lectin of normal and tumoral prostate epithelial cells with binding affinity to endothelial cells.

The mechanism of bone metastasis of prostate cancer involves the interaction of cell surface receptor(s) on cancer cells with ligand(s) on bone marrow endothelial cell surfaces. The rat galactosyl receptor gene generates two mRNA species by differential splicing: one species encodes a protein identical to the minor form of hepatocyte asialoglycoprotein receptor and displays a galactose/N‐acetyl‐galactosamine‐recognition domain; the other encodes a protein with identical intracellular and transmembrane domains but with a different extracellular domain lacking the carbohydrate‐recognition domain (CRD). Both proteins appear to coexist as a heterooligomer on the surface of normal mouse, rat, and human prostate epithelial cells and human prostate cancer cells, including the PC‐3 cell line. The CRD of galactosyl receptor mediates adhesion of normal and tumoral prostate cells to the surfaces of a human bone marrow endothelial cell line. The use of inhibitors targeting the CRD would be very valuable in hindering the binding of prostate cancer cells to endothelial cells, thus decreasing the incidence of hematogenous metastasis to bone.

Antral follice counts (AFC) predict ovarian response and pregnancy outcomes in oocyte donation cycles.

PurposeAntral follicle count (AFC) is used as a marker of ovarian response. We assessed its value in predicting pregnancy outcomes in ovum donation cycles by retrospective review.MethodsOocyte donors (nu2009=u200994) underwent ovarian hyperstimulation using rFSH and GnRH-antagonists. Recipients were synchronized using GnRH-agonist down-regulation followed by fixed dose of estrogen and progesterone following hCG. Outcomes measured included correlation of AFC to pregnancy outcomes and cycle characteristics in those with and without clinical and ongoing-delivered cycles.ResultsAFC significantly correlated with clinical [Exp β 1.12; 95% CI: 1.02–1.23, pu2009<u20090.05] and ongoing-delivered pregnancy [Exp β 1.10; 95% CI: 1.01–1.20, pu2009<u20090.05]. Significantly greater AFC, total and M-2 oocytes, and cycles resulting in cryopreserved embryos were seen in clinical and ongoing-delivered cycles.ConclusionsAFC predicts cycle stimulation responses and clinical outcomes and may serve as a guide for dosing protocols and in choosing to proceed with the most optimal cycle.

Reproductive Outcome After Sterilization Reversal in Women of Advanced Reproductive Age

Objective:Our objective was to assess the clinical outcome of tubal reversal in women of advanced reproductive age.Methods:A multicenter retrospective chart review of 153 patients who underwent a tubal ligation reversal was carried out. Patients were evaluated according to age. All patients had documented ovulation and a partner with a normal semen analysis by WHO criteria. Outcome measures included rates of clinical pregnancy, ectopic pregnancy, spontaneous abortion, and live birth, and the time to conception.Results:Clinical pregnancy rates were significantly lower in women ≥40 compared to younger groups. The time to conception was significantly shorter for women <30 compared to women ≥35. No pregnancies occurred in women ≥42.Conclusions:Our data support the judicious use of sterilization reversal for infertile women with no male factor through their early forties. Women ≥42 years should be especially counseled as to the very low success rates.

Screening Oocyte Donors for Cystic Fibrosis Using Multiplex PCR Amplification of the CFTR Gene from Buccal Cell DNA

For the past decade, oocyte donation has been used successfully to treat a variety of female reproductive disorders. Presently, more than 3000 cases are being performed in the United States and the number of cases continues to grow annually (1). The increased demand for services is due in part to extending care to women of advanced reproductive age (>40 years). Essential to establishing a registry is designing a protocol for the screening and selecting of women to enlist as suitable donors. Guidelines have been published by the American Society of Reproductive Medicine to help direct clinics with donor screening (2). Minimal genetic testing for autosomal recessive diseases known to be prevalent in different ethnic groups is recommended, but in general, genetic health is largely determined by history alone. Cystic fibrosis (CF) represents one of the most prevalent genetic illnesses in the population, occurring in 1 in 2500 live births, with a carrier frequency of 1 in 25 Caucasians (3,4). CF is a chronic, progressive, and debilitating disease that ultimately runs a protracted course with a median survival of 29 years. Inheritance is along autosomal recessive lines and typically results from mutations in a single gene, the cystic fibrosis transmembrane conductance regulator (CFTR), located on the long arm of chromosome 7. Presently, more than 400 mutations of this gene have been identified, with changes in AF508 being the most common (68-85%). Because of the relatively high frequency of CF carriers in the general Caucasian population, many women interested in being gamete donors may be identified to carry CF prior to participation. Determination of the carrier status of sperm donors has been published elsewhere (4), but attempts at screening oocyte donors have not been reported. We determined the frequency of CF carrier status in our oocyte donation program and surveyed the attitude of recipients of donor oocytes regarding genetic screening of our donor pool.