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J L Simpson

Publications and source records attributed to J L Simpson.

At least 91 records · Page 5Linked to original sources
PubMed1994

Significance of septations in isolated fetal cystic hygroma detected in the first trimester.

Recent reports have indicated an increased risk for fetal chromosome abnormalities, especially autosomal trisomy, in fetuses with isolated cystic hygroma, or prominent nuchal membranes, detected by ultrasonography during the first trimester. However, these reports present contradictory information regarding the prognostic significance of septations within the cystic hygroma. We evaluated, in blind fashion, 55 consecutive cases of isolated fetal cystic hygroma detected at or before 13.9 weeks' gestation to determine the association between septations and fetal chromosome complement. Septations were associated (P < 0.05) with an increased risk for fetal chromosome abnormalities. However, the incidence of chromosome abnormalities was also increased (12.5 per cent) among cases not characterized by septations. Thus, we believe it prudent to offer invasive prenatal testing to all women found to be carrying fetuses with cystic hygroma, irrespective of the presence or absence of septations.

Adult↗
PubMed1994

Adverse perinatal outcome in patients screen-positive for neural tube defects and fetal Down syndrome.

An association between various abnormal mid-trimester maternal serum analyte values and adverse perinatal outcome has been reported. From an original sample of 14,857 women, we observed five women who were 'screen-positive' for both neural tube defects [maternal serum alpha-fetoprotein (MSAFP) > or = 2.5 multiples of the median] and Down syndrome [risk > or = 1/274 using MSAFP, maternal serum unconjugated oestriol (MSuE3), maternal serum human chorionic gonadotropin (MShCG), and maternal age]. The four patients who elected to undergo amniocentesis all demonstrated both normal karyotype and normal amniotic fluid AFP levels. All five cases were associated with intrauterine growth retardation (IUGR) and abnormal pregnancy outcomes. Two cases exhibiting severe IUGR on ultrasound examination were terminated at 19.1 and 21.2 weeks, respectively; the former also exhibited fetal calcifications and positive maternal serology for toxoplasmosis. In another case, fetal demise occurred at 36 weeks' gestation in a patient who had been treated for syphilis in the second trimester. Neither infection was confirmed in fetal tissue studies. Though resulting in live births, the remaining two cases required operative deliveries; emergency Caesarean sections for fetal distress were performed at 38 and 32 weeks, respectively, the latter case being associated with severe pre-eclampsia. We conclude that elevated mid-trimester MSAFP levels concurrent with maternal serum analyte values associated with increased risk for fetal Down syndrome may presage a poor perinatal outcome, particularly IUGR and possibly congenital infection.

Adult↗
PubMed1994

Isolating fetal cells in maternal circulation for prenatal diagnosis.

Fetal cells unequivocally exist in and can be isolated from maternal blood. Erythroblasts, trophoblasts, granulocytes and lymphocytes have all been isolated by various density gradient and flow sorting techniques. Chromosomal abnormalities detected on isolated fetal cells include trisomy 21, trisomy 18, Klinefelter syndrome (47,XXY) and 47,XYY. Polymerase chain reaction (PCR) technology has enabled the detection of fetal sex, Mendelian disorders (e.g. beta-globin mutations), HLA polymorphisms, and fetal Rhesus (D) blood type. The fetal cell type that has generated the most success is the nucleated erythrocyte; however, trophoblasts, lymphocytes and granulocytes are also considered to be present in maternal blood. Fetal cells circulate in maternal blood during the first and second trimesters, and their detection is probably not affected by Rh or ABO maternal-fetal incompatibilities. Emphasis is now directed toward determining the most practical and efficacious manner for this technique to be applied to prenatal genetic diagnosis. Only upon completion of clinical evaluations could it be considered appropriate to offer this technology as an alternative to conventional invasive and non-invasive methods of prenatal cytogenetic diagnosis.

Cell Separation↗
PubMed1994

Are obese women at higher risk for producing malformed offspring?

OBJECTIVE: Our purpose was to determine whether obese women and underweight women have an increased risk of birth defects in their offspring. STUDY DESIGN: A geographically based case-control study of women living in California and Illinois was performed. There were 499 mothers of offspring with neural tube defects, 337 mothers of offspring with other major birth defects, and 534 mothers of offspring without birth defects who participated. RESULTS: Compared with women of normal weight, women who were extremely obese before pregnancy (body mass index > or = 31 kg/m2) showed a significantly increased risk of having an infant with a neural tube defect (odds ratio 1.8, 95% confidence interval 1.1 to 3.0), especially spina bifida (odds ratio 2.6, 95% confidence interval 1.5 to 4.5), after adjustments for age, race, education, and family income. Obese women also had significantly increased risks (p < 0.05) of having an infant with other defects of the central nervous system, great vessel defects, ventral wall defects, or other intestinal defects. CONCLUSION: Our data suggest that offspring of obese women (but not underweight women) are at an increased risk of neural tube defects and several other malformations. If these findings are confirmed, further research will be necessary before it can be concluded that weight reduction before pregnancy will lower the risk of birth defects among obese women. Until then, obese women can address their risk of birth defects with the same measures that are recommended for all women, such as adequate daily intake of folic acid and alpha-fetoprotein screening to identify malformed fetuses.

Adult↗
PubMed1994

Lack of heritability in ovarian germ cell malignancies.

OBJECTIVE: Our purpose was to determine whether relatives of patients with ovarian germ cell malignancies not associated with sex chromosome abnormalities are at increased risk for similar tumors. STUDY DESIGN: We reviewed pedigrees of 78 presumptive 46,XX patients (ages ranging from newborn to 20 years) with malignant ovarian germ cell tumors, excluding cases of dysgerminoma and gonadoblastoma. A three-generation family history of each proband was reviewed specifically to identify cancer in any family member. RESULTS: Seventy-eight mothers, 87 sisters, 135 aunts, and 156 grandmothers were surveyed. None had a malignant ovarian germ cell neoplasm or other malignant ovarian neoplasm. CONCLUSION: First- and second-degree relatives of probands with ovarian germ cell malignancies do not have an increased risk for similar tumors. These findings were not predicted because of the well-recognized association of hereditary tumors and early age of onset.

Adolescent↗
PubMed1994

Amniocentesis performed at 14 weeks' gestation or earlier: comparison with first-trimester transabdominal chorionic villus sampling.

OBJECTIVE: To compare our initial experiences with early amniocentesis and transabdominal chorionic villus sampling (CVS). METHODS: We compared the diagnostic and pregnancy outcomes of our initial 250 patients undergoing early amniocentesis (at or before the 14th completed week of gestation) or transabdominal CVS (performed between 9.5-12.9 weeks' gestation). In both groups, the indication for prenatal diagnosis was advanced maternal age (35 years or older at estimated date of delivery). RESULTS: No diagnostic errors were made using either technique, and the culture failure rate for both methods was 0.8% (two of 250). Seven cytogenetic abnormalities in the early amniocentesis group and seven in the transabdominal CVS group were detected. Nine of the 250 women undergoing early amniocentesis reported spontaneous miscarriages following the procedure, compared to five in the transabdominal CVS group. The loss rates were 3.8% in the early amniocentesis group and 2.1% in the transabdominal CVS group among continuing pregnancies. Frequencies of premature delivery, small for gestational age infants, and associated structural defects in both groups were comparable. CONCLUSIONS: At this time, early amniocentesis cannot be assumed to be equal to conventional transabdominal CVS or amniocentesis with regard to safety or accuracy; only a large cohort randomized study will adequately determine the safety and efficacy of early amniocentesis.

Abdomen↗
PubMed1994

Ultrasound-guided fetal skin sampling for prenatal diagnosis of genodermatoses.

OBJECTIVE: To evaluate the safety and diagnostic efficacy of ultrasound-guided fetal skin sampling for the prenatal diagnosis of genodermatoses. METHODS: Seventeen pregnancies seen over 6.5 years were analyzed retrospectively. Fifteen were at risk for junctional epidermolysis bullosa and two for recessive dystrophic epidermolysis bullosa. Under ultrasound guidance, a biopsy forceps was inserted through a 14-gauge catheter and directed toward the fetus (thorax, back, or buttocks) to obtain skin samples. The procedures were performed at a mean of 18.3 weeks' gestation (range 16.5-19.5). RESULTS: Fetal skin sampling was successful in all cases; the mean number of biopsies taken was 3.6 (range two to five). Five of the 17 fetuses were determined to be affected, each with junctional epidermolysis bullosa; these pregnancies were terminated electively and the prenatal diagnoses confirmed. The remaining 12 pregnancies resulted in the delivery of healthy infants at or after 37 weeks' gestation. There were no pregnancy-related complications, specifically preterm rupture of the membranes or preterm labor. Three of the 12 infants had minor skin blemishes believed to be due to the skin sampling. CONCLUSION: Ultrasound-guided fetal skin sampling is the procedure of choice when fetal skin is required for prenatal diagnosis of genodermatoses.

Biopsy↗
PubMed1993

Isolating fetal cells from maternal blood. Advances in prenatal diagnosis through molecular technology.

OBJECTIVES: To review the rationale for and progress toward the goal of isolating and analyzing fetal cells circulating in maternal blood, and to explore the feasibility of this method in providing noninvasive prenatal cytogenetic diagnosis. DATA SOURCES: Critical review of data published since the first report (1969) of fetal metaphases in maternal blood. Emphasis is placed on data since the demonstration by polymerase chain reaction (PCR) in 1989 and 1990 that fetal cells indeed exist in maternal blood. DATA SYNTHESIS: Clinical evaluations have not yet been conducted, but it is already clear that molecular technologies have allowed the unequivocal demonstration of fetal cells in maternal blood. Using PCR, our own group and others have demonstrated Y sequences and single gene sequences (eg, hemoglobin LeporeBoston) in maternal blood. Thus, fetal DNA sequences indeed exist in maternal blood. Among the various candidate cells, the most promising appear to be fetal nucleated red blood cells. We isolated nucleated red blood cells on the basis of flow-sorting for the transferrin receptor and glycophorin-A. Enriched samples were then subjected to fluorescence in situ hybridization with chromosome-specific probes. This approach allowed us to detect trisomy 21 and trisomy 18, work later confirmed by others. CONCLUSIONS: Isolating and analyzing fetal cells from maternal blood is clearly possible. Several key biologic questions remain--the optimal cells for isolation, frequency of cells in maternal blood, timing during gestation for maternal blood sampling, and the likelihood of persistence of fetal cells after delivery. Clinical evaluations planned by the National Institute of Child Health and Human Development will determine the sensitivity and specificity of this method and its precise role in prenatal cytogenetic diagnosis.

Aneuploidy↗
PubMed1993

Moderate caffeine use and the risk of spontaneous abortion and intrauterine growth retardation.

OBJECTIVE: To examine the relationship between caffeine consumption during pregnancy and the occurrence of spontaneous abortion and intrauterine growth retardation. DESIGN, SETTING, AND PATIENTS: A cohort of 431 women, enrolled in a multicenter study within 21 days of conception, was monitored throughout pregnancy to determine (1) caffeine exposure, (2) exposure to other risk factors, (3) fetal growth as assessed by ultrasonography, and (4) pregnancy outcome. OUTCOME MEASURES: Spontaneous abortion, intrauterine growth, birth weight, and head circumference. RESULTS: The mean (+/- SD) first-trimester caffeine consumption was not significantly higher in women who aborted (125.9 +/- 123.1 mg) than in women who delivered liveborn infants (111.6 +/- 107.0 mg) (P = 34). The adjusted odds ratio (OR) for spontaneous abortion was 1.15 (95% confidence interval [CI], 0.89 to 1.49). Early fetal growth, assessed by crown-rump length on ultrasonographic examination, was not affected by caffeine. Although the group consuming the most caffeine (> 300 mg/d) had a significantly higher proportion of babies with birth weights and head circumferences below the 10th percentile in the crude analysis, the association with caffeine was no longer significant when other risk factors (notably smoking) were taken into account. The adjusted ORs were 1.11 (95% CI, 0.88 to 1.40) for decreased birth weight and 1.09 (95% CI, 0.86 to 1.37) for smaller head circumference. CONCLUSIONS: Close monitoring of a cohort identified very soon after conception enabled us to identify all abortions after 21 days postconception, monitor intrauterine growth prospectively, and track caffeine use. Despite this intensive surveillance, we found no evidence that moderate caffeine use increased the risk of spontaneous abortion, intrauterine growth retardation, or microcephaly after accounting for other risk factors.

Abortion, Spontaneous↗
PubMed1993

Are physical activity and employment related to preterm birth and low birth weight?

OBJECTIVE: The purpose of this study was to review the validity of published studies that consider modifying physical activity during pregnancy to decrease preterm births and low birth weight. STUDY DESIGN: Presented is a critical review of extant literature, both case-control studies and studies of pregnant women followed up in cohort fashion. RESULTS: Studies both showing and not showing an association between employment and adverse outcome exist. However, no randomized trials have been reported. The most plausible associations exist for prolonged standing, long working hours, and lifting heavy objects. CONCLUSION: Until the biologic basis of parturition is known, definitive conclusions are probably not possible. Proposals to require pregnancy leave for all employees seem premature. However, physicians must be sensitive to dilemmas faced by some employees and encourage voluntary leave for those placed in positions characterized by occupational fatigue.

Confounding Factors, Epidemiologic↗
PubMed1993

Gender verification in competitive sports.

The possibility that men might masquerade as women and be unfair competitors in women's sports is accepted as outrageous by athletes and the public alike. Since the 1930s, media reports have fuelled claims that individuals who once competed as female athletes subsequently appeared to be men. In most of these cases there was probably ambiguity of the external genitalia, possibly as a result of male pseudohermaphroditism. Nonetheless, beginning at the Rome Olympic Games in 1960, the International Amateur Athletics Federation (IAAF) began establishing rules of eligibility for women athletes. Initially, physical examination was used as a method for gender verification, but this plan was widely resented. Thus, sex chromatin testing (buccal smear) was introduced at the Mexico City Olympic Games in 1968. The principle was that genetic females (46,XX) show a single X-chromatic mass, whereas males (46,XY) do not. Unfortunately, sex chromatin analysis fell out of common diagnostic use by geneticists shortly after the International Olympic Committee (IOC) began its implementation for gender verification. The lack of laboratories routinely performing the test aggravated the problem of errors in interpretation by inexperienced workers, yielding false-positive and false-negative results. However, an even greater problem is that there exist phenotypic females with male sex chromatin patterns (e.g. androgen insensitivity, XY gonadal dysgenesis). These individuals have no athletic advantage as a result of their congenital abnormality and reasonably should not be excluded from competition. That is, only the chromosomal (genetic) sex is analysed by sex chromatin testing, not the anatomical or psychosocial status. For all the above reasons sex chromatin testing unfairly excludes many athletes. Although the IOC offered follow-up physical examinations that could have restored eligibility for those 'failing' sex chromatin tests, most affected athletes seemed to prefer to 'retire'. All these problems remain with the current laboratory based gender verification test, polymerase chain reaction based testing of the SRY gene, the main candidate for male sex determination. Thus, this 'advance' in fact still fails to address the fundamental inequities of laboratory based gender verification tests. The IAAF considered the issue in 1991 and 1992, and concluded that gender verification testing was not needed. This was thought to be especially true because of the current use of urine testing to exclude doping: voiding is observed by an official in order to verify that a sample from a given athlete has actually come from his or her urethra. That males could masquerade as females in these circumstances seems extraordinarily unlikely. Screening for gender is no longer undertaken at IAAF competitions.

Disorders of Sex Development↗
PubMed1993

Deletion (X)(q26.1-->q28) in a proband and her mother: molecular characterization and phenotypic-karyotypic deductions.

During a routine prenatal diagnosis we detected a female fetus with an apparent terminal deletion of an X chromosome with a karyotype 46,X,del(X)(q25); the mother, who later underwent premature ovarian failure, had the same Xq deletion. To further delineate this familial X deletion and to determine whether the deletion was truly terminal or, rather, interstitial (retaining a portion of the terminal Xq28), we used a combination of fluorescence in situ hybridization (FISH) and Southern analyses. RFLP analyses and dosage estimation by densitometry were performed with a panel of nine probes (DXS3, DXS17, DXS11, DXS42, DXS86, DXS144E, DXS105, DXS304, and DXS52) that span the region Xq21 to subtelomeric Xq28. We detected a deletion involving the five probes spanning Xq26-Xq28. FISH with a cosmid probe (CLH 128) that defined Xq28 provided further evidence of a deletion in that region. Analysis with the X chromosome-specific cocktail probes spanning Xpter-qter showed hybridization signal all along the abnormal X, excluding the possibility of a cryptic translocation. However, sequential FISH with the X alpha-satellite probe DXZ1 and a probe for total human telomeres showed the presence of telomeres on both the normal and deleted X chromosomes. From the molecular and FISH analyses we interpret the deletion in this family as 46,X,del(X) (pter-->q26::qter). In light of previous phenotypic-karyotypic correlations, it can be deduced that this region contains a locus responsible for ovarian maintenance.

Adult↗
PubMed1993

Prospects for prevention of neural tube defects by vitamin supplementation.

Recent studies have resolved the debate over the role of vitamins in preventing neural tube defects. The British Medical Research Council trial demonstrated that 4 mg of folate daily, but not other vitamins, prevented 72% of recurrences. The Hungarian trial prevented neural tube defects in women who had not previously had affected children by giving multivitamins containing 0.8 mg of folate. The US Public Health Service currently recommends that women at risk for becoming pregnant take 0.4 mg of folate daily. Unfortunately, most pregnancies are unplanned, and women not planning to become pregnant may not follow this recommendation. Therefore, the US Food and Drug Administration is exploring methods of food fortification. Because large doses of folate have been reported to ameliorate B12 deficiency anemia while allowing neurologic damage to progress, and to cause electroencephalogram abnormalities in epileptics, it is important to plan fortification carefully and to monitor both toxicity and benefits.

Ascorbic Acid↗