Biomedical subjects

E J Thomason

Publications and source records attributed to E J Thomason.

5 recordsLinked to original sources

PubMed1995

Validation of an embryotoxicity assay.

PROBLEM: Culture of mouse blastocysts has served as a tool for identifying various embryotoxic factors in human serum. While inactivated, sera from recurrently aborting women inhibit mouse blastocyst development in vitro. Variation in results from individual serum samples has limited the usefulness of this assay in establishing a new classification of idiopathic recurrent spontaneous abortion (RSA). METHOD: Two-cell embryos were collected from superovulated mated CB6F1/J mice and cultured in Ham's F-10 media supplemented with 10% fetal bovine serum (FBS) or tested human serum at 37 degrees C with 5% CO2 and high humidity. Each sample was assayed in triplicate using three mice with at least five embryos from the same mouse per dish. Development was evaluated at 72 h and the frequency of atretic embryos was recorded. RESULTS: Intrasample (interassay) variation yielded a coefficient of variation of 9%. When repeated, samples from a given individual were evaluated and the coefficient of variation was 8.7%. Interoperator variability was 4% interassay and 2% intrassay. Atresia of embryos was 23% when incubated with FBS (N = 122), 21% in FC (N = 122), and in the sera of patients with RSA 34.6% (N = 95). Results of percentage of atresia from the fertile control group had a nonparametric distribution. Using 2.2 multiples of the median to determine the 95% confidence interval, a threshold at 44.0% of atresia was established. CONCLUSIONS: The critical step in maintaining low variability in this bioassay is to control mouse variability by averaging the percentage atresia from different mice as embryo donors for each tested serum. A subgroup of 24% (23/95) RSA patients who displayed embryotoxic activity was identified with a specificity of 95% and positive predictive value of 83%, P = 0.001.

Abortion, Habitual↗

PubMed1995

Preimplantation factor (PIF) predicts subsequent pregnancy loss.

PROBLEM: To evaluate the ability of preimplantation factor (PIF) measured in the lymphocyte/platelet binding assay (LPBA) to predict subsequent spontaneous abortion. METHOD: Serum from 57 women experiencing first trimester pregnancy losses were studied using the LPBA (46 women conceived after in vitro fertilization and embryo transfer for treatment of infertility and 11 with a history of unexplained recurrent spontaneous abortion conceived spontaneously). The assay employs a combination of heat inactivated sera with donor O+ lymphocytes and platelets, complement and an antibody against CD2. Chromosome analysis was performed on 32 of the abortuses. Results of PIF assay were compared between karyotypically normal and abnormal abortuses. RESULTS: PIF assay was negative in all 57 women at the time of abortion. Among 12 karyotypically normal abortuses only 1 woman (8%) had an initial positive PIF, 11 (92%) had negative PIF. Serial PIF assays were performed on 15 women. PIF assay became negative a minimum of two weeks prior to demonstration of intrauterine demise at a time when hCG concentrations remained elevated. A trend to subnormal was seen in women with normal when compared to those with abnormal abortus karyotype, but the numbers were too small to reach statistical significance (P = 0.09). CONCLUSION: Measurement of PIF throughout the first trimester of pregnancy predicts subsequent pregnancy loss.

Abortion, Habitual↗

PubMed1995

Prevalence of embryotoxic factor in sera from women with unexplained recurrent abortion.

PROBLEM: The presence of embryotoxic factors in sera from women with recurrent spontaneous abortion (RSA) has been proposed as a basis for classification of unexplained RSA. To determine the prevalence of circulating embryotoxins among women with idiopathic RSA, sera from 160 women were studied using the mouse blastocyst assay. METHODS: Two-cell embryos were collected from superovulated mated (CB6F1/J mice and cultured in media supplemented with fetal bovine serum (FBS) or 10% serum at 37 degrees C with 5% CO2 and high humidity. Each assay was run in triplicate using three mice with at least five embryos from each mouse. Results were determined by calculating the average percentage atresia for each mouse. FBS, known to support embryo proliferation, was used to control in each assay. RESULTS: The prevalence of embryotoxic factors among women experiencing RSA was 24.4% (39/160). There is no correlation found between the presence of embryotoxicity and phospholipid antibodies, lupus anticoagulant, and thyroglobulin/microsomal antibodies. CONCLUSION: The embryotoxicity assay can serve as a basis for a new approach for classification of unexplained recurrent spontaneous abortion.

Abortion, Habitual↗

PubMed1995

Systemic CD56+ cells can predict pregnancy outcome.

PROBLEM: To evaluate differences in circulating CD56+ cells between successful and unsuccessful pregnancies, 114 pregnant women were studied prospectively. METHOD: Seventy women had a history of infertility (INF) and 44 had two or more previous spontaneous abortions (RSA). Among the infertile women, 12 were donor egg recipients (DER) and 15 underwent intracytoplasmic sperm injection (ICSI) for treatment of male factor infertility. Nineteen women were carrying multiple gestations (MG) and 55 had singleton gestations (SG). Thirteen additional women were receiving intravenous immunoglobulin (IVIg). RESULTS: The percentage of CD56+ cells was determined in 310 blood samples from 114 pregnant women by flow cytometry. The prevalence of women with persistent elevation of percent of 56+ cells (> 12%) was 58% among DER, 73% among ICSI, 37% among MG, 22% among SG, 18% among RSA, and 39% among INF. Thirteen women with SG received IVIG, 10 had CD56+ cells greater than 12% and all 13 experienced live births. Women with percentage CD56+ cells persistently greater than 12% who were not DER, not ICSI, not receiving IVIg, and not carrying MG had a live birth rate of 11%. Women with greater than 12% CD56+ cells had normal karyotype in 78% of concepti studied in contrast to women less than 12% CD56+ cells who had 68% abnormal karyotypes (P = 0.04). CONCLUSION: Elevated CD56+ cells in pregnant women who are not DER, not ICSI, not receiving IVIg, and not carrying MG predicts loss of a karyotypically normal conceptus with a specificity of 87% and positive predictive value of 78%. While the specificity value of this test is high in both infertile and RSA populations, the sensitivity is 86% in RSA and only 54% in INF suggesting this test does not identify all losses among INF. It may identify a subset of pregnancies at risk for loss of a karyotypically normal embryo that may respond to treatment with IVIg.

Abortion, Habitual↗

PubMed1995

A novel bioassay for detection of preimplantation factor (PIF).

PROBLEM: To identify the presence of vital preimplantation embryos in vivo in humans, a newly observed phenomenon based on autorosette formation between lymphocytes and platelets, when treated with pregnant sera, was used as a marker. METHOD: Serum samples were obtained from 65 patients on the fourth day after embryo transfer (ET). Sera from 10 healthy males and 47 nonpregnant women were used as controls. The preimplantation factor (PIF) was detected by using blood group O+ donor lymphocytes and platelets incubated with blinded serum in the presence of anti-CD2 antibody and rabbit complement. Human chorion gonadotropin (hCG) concentrations were determined 7 days later and compared with results of the lymphocyte-platelets assay. Implantation was confirmed by ultrasonographic evidence of presence of an intrauterine gestational sac. The role of platelet activating factor (PAF) in the observed phenomena was studied experimentally. RESULTS: Significantly more lymphocyte-platelet rosette formations were observed when sera from women who successfully implanted were compared to sera from women who failed to implant. This assay yielded a specificity of 95%, sensitivity of 88%, positive predictive value of 94%, and negative predictability of 90%. PAF added directly to the cell suspension and tested sera controls did not influence the percentage of lymphocyte/platelets rosettes. CONCLUSION: The application of PIF assay will enable the identification and study of early pregnancy events before the implantation occur. PAF by itself is not responsible for the rosette formation.

Biological Assay↗