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Biomedical subjects

E R Wassman

Publications and source records attributed to E R Wassman.

18 recordsLinked to original sources
PubMed1993

Fetal cells in the maternal circulation. Technical considerations for practical application to prenatal diagnosis.

Recent advances in cell separation technology and DNA analytic techniques leave little doubt as to the presence of fetal cells in the maternal circulation. The potential of using these cells for genetic analysis is compelling. The practical aspects of establishing a universal method utilizing the new capabilities in clinical practice have not been addressed to date. The major hurdles that still need to be traversed before this technology is universally adopted include the identification of appropriate sampling and separation methods yielding fetal cells amenable to genetic analysis by rapid DNA technologies, clinical studies of appropriate statistical power to validate and compare this approach to current genetic testing, and comparison of this approach to other noninvasive paradigms such as triple screening. Despite the tremendous value of noninvasive genetic screening, the rigorous course required to progress from description of scientific capability to validation of a clinical test must not be ignored or rushed for financial considerations.

DNA↗
PubMed1990

Second trimester maternal serum pregnancy specific beta-1 glycoprotein (SP-1) levels in normal and Down syndrome pregnancies.

Maternal serum pregnancy specific beta-1 glycoprotein (SP-1) levels in the second trimester may be predictive of Down syndrome (DS). An enzyme immunoassay was used to measure SP-1 sera from 46 DS pregnancies and 117 normal control women matched for maternal age, gestational age, and length of storage. In the normal control samples, there were slight correlations between the SP-1 concentration and maternal age. The maternal serum SP-1 levels increased with each week of gestation from 15 to 20 weeks. All but one of the DS sera had SP-1 levels greater than the normal median. Using a cutoff of 2.8 multiples of the median (MoM), 15.2% of the DS pregnancies were detected with a false-positive rate of 4.3%. A combinational logistic regression analysis of maternal age and pregnancy related serum proteins will detect additional DS pregnancies and decrease the false-positive rate. The combination of maternal age and SP-1 detected 33 (71.7%) of Down syndrome pregnancies. The addition of maternal serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) levels allowed for the detection of 36 (78.3%) of the DS pregnancies with a decrease in the false-positive rate to 3.4%. The measurement of other serum constituents in conjunction with AFP appears to be a valuable addition to current screening programs, as this can increase the proportion of DS cases detected prenatally.

Adolescent↗
PubMed1990

Performing cytogenetic studies on ascitic, amniotic and hygroma fluid.

The importance of obtaining cytogenetic studies on antenatally diagnosed structural malformations is well recognized. In two cases, three fetal compartments were sampled, each resulting in successful cytogenetic studies. Fluid was obtained under ultrasound guidance from amniotic fluid, fetal ascites and cystic hygroma fluid. Fluid from the hygroma itself may be the easiest compartment to analyze.

Amniocentesis↗
PubMed1989

Prenatal detection of cyclopia associated with interstitial deletion of 2p.

We report on a case of synophthalmic cyclopia and alobar holoprosencephaly associated with an interstitial deletion of the short arm of chromosome 2: del(2)(p21p23). This is the second case with this phenotype in association with deletion in this region, and comparison with the infrequent other cases of 2p deletions suggests a causal relationship between band 2p21 and cyclopia.

Abnormalities, Multiple↗
PubMed1989

"Possibly" de novo translocations: prenatal risk counseling.

De novo rearrangements incidentally found at prenatal diagnosis may carry an increased risk of abnormal outcome. Situations in which the paternal chromosomes cannot be analyzed (e.g., artificial insemination, nonpaternity, deceased or otherwise unavailable father) are only "possibly" de novo. In our series of 23,495 prenatal diagnoses we unexpectedly found 67 balanced translocations. Of these, 26 were Robertsonian and 41 were reciprocal. A total of 45 (67%) of these translocations were inherited, and 19 (28%) were apparently de novo. Inherited translocations were maternal in 25 cases (55%) and paternal in 20 cases (45%). Follow-up was available in 87% overall, and revealed abnormal outcomes in 2/15 de novo cases, and 2/38 inherited cases. We suggest that 10% may be a reasonable estimate of risk for de novo translocations found at prenatal diagnosis. Given the observed distributions of inherited cases, a lower risk of abnormal outcome should be counseled in "possibly" de novo cases.

Adult↗
PubMed1989

Amniotic fluid acetylcholinesterase ratios in prenatal diagnosis of fetal abnormalities.

This study examined 141 pregnancies with acetylcholinesterase in the amniotic fluid to determine if an acetylcholinesterase/pseudocholinesterase ratio cutoff could be set to distinguish between neural tube defects, ventral wall defects, other fetal defects, and pregnancy problems. Amniotic fluid specimens with positive or faintly positive acetylcholinesterase bands were studied. They were scanned and analyzed for the acetylcholinesterase/pseudocholinesterase ratio. In 62 of 65 fluid samples from open neural tube defects, the acetylcholinesterase/pseudocholinesterase ratios were greater than 0.13. All cases with ventral wall defects (n = 29), fetal blood contamination (n = 16), or fetal ascites (n = 2) had acetylcholinesterase/pseudocholinesterase ratios less than 0.13. Samples of cystic hygroma fluid (n = 10) had acetylcholinesterase/pseudocholinesterase ratios greater than 0.13. Two patients with fetal teratomas had intermediate values. All patients with normal outcomes but positive acetylcholinesterase had ratios of less than 0.12. Acetylcholinesterase/pseudocholinesterase ratios are a valuable part of a prenatal program to accurately diagnose fetal abnormalities.

Acetylcholinesterase↗
PubMed1989

Prenatal screening for Down syndrome with maternal serum human chorionic gonadotropin levels.

Human chorionic gonadotropin levels in midtrimester pregnancies may be predictive of Down syndrome. A commercially available enzyme immunoassay kit was used to measure the beta-subunit of human chorionic gonadotropin in maternal sera from 38 Down syndrome pregnancies and 114 gestational age matched controls. The human chorionic gonadotropin levels were also assayed in 236 normal sera and plasma samples to determine normative values and appropriate individual corrections. Serum and plasma human chorionic gonadotropin levels are closely correlated and are stable at room temperature, during refrigeration, and throughout freeze-thaw cycles. There is no correlation between the human chorionic gonadotropin level and maternal age, weight, or race. However, the human chorionic gonadotropin level decreases with each week of gestation from 15 to 19 weeks. Medians for each week of gestation were established to account for this variable. Up to 63% of the Down syndrome pregnancies were detected with a cutoff of 2.0 multiples of the normal median. A computational combination of human chorionic gonadotropin and maternal serum alpha-fetoprotein testing will detect additional Down syndrome pregnancies and decrease the false-positive rate. The measurement of human chorionic gonadotropin appears to be a valuable addition to maternal serum alpha-fetoprotein screening programs that can significantly increase the proportion of Down syndrome cases diagnosed.

Blood Specimen Collection↗
PubMed1986

Interstitial deletion of the long arm of chromosome 2 in a malformed infant with karyotype 46,XX,del(2)(q31q33).

We describe a malformed newborn girl with an interstitial deletion of the long arm of chromosome 2 (karyotype: 46,XX,del(2)(q31q33)). This is the first report of this particular chromosome abnormality that includes autopsy findings. Comparison with previous cases in the literature suggests that this particular deletion uniformly results in developmental delays, craniofacial changes, and occasionally results in microcephaly, low-set ears, and hand and foot abnormalities.

Abnormalities, Multiple↗
PubMed1985

Computerized tomography of the foramen magnum: achondroplastic values compared to normal standards.

Computerized tomographic dimensions of the foramen magnum of 63 achondroplastic individuals were compared to standards established for nonachondroplastic individuals. The size of the foramen magnum in patients with achondroplasia was small at all ages, particularly in those with serious neurologic problems. The data suggest that measurement of the foramen magnum may identify achondroplastic individuals at high risk of developing neurologic complications.

Achondroplasia↗
PubMed1984

Apnea and sudden unexpected death in infants with achondroplasia.

Thirteen infants with achondroplasia and sudden unexpected death or unexplained apnea were discovered through nonsystematic retrospective case collection. Most were initially thought to have died from sudden infant death syndrome. However, historical and pathologic findings suggest that many of these infants had apnea and sudden unexpected death secondary to acute or chronic compression of the lower brainstem or cervical spinal cord. Infants with achondroplasia evidently are at considerably increased risk for such deaths between 1 month and 1 year of age. Appropriate intervention, given these previously unrecognized risks, may include cervical restraint, polysomnographic evaluation, and apnea monitoring.

Achondroplasia↗
PubMed1982

Transformation with DNA from 5-azacytidine-reactivated X chromosomes.

It has been shown that 5-azacytidine (5-Aza-Cyd) can reactivate genes on the inactive human X chromosome. It is assumed that the 5-Aza-Cyd acts by causing demethylation of the DNA at specific sites, but this cannot be demonstrated directly without a cloned probe. Instead, we have utilized the technique of DNA-mediated transformation to show that the 5-Aza-Cyd-induced reactivation occurs at the DNA level. DNAs from various mouse-human or hamster-human hybrid cell lines, deficient for mouse or hamster hypoxanthine phosphoribosyltransferase (HPRT, EC 2.4.2.8) and varying in whether they contained either an active or inactive human X chromosome, were used in transformation of HPRT- cells. DNA from the active human X chromosome-containing cell lines yielded HPRT+ transformants, whereas DNA from the inactive X chromosome-containing cells lines did not. The inactive X chromosomal DNA was able to transform thymidine kinase-deficient mouse cells, indicating that the DNA solution was normal. These results confirm that inactivation of the X chromosome involves a DNA modification. Furthermore, DNAs from three cell lines with a 5-Aza-Cyd-reactivated X chromosome also transform HPRT- cells, demonstrating that the 5-Aza-Cyd has altered the DNA structure and supporting the idea that methylation plays a role in X chromosome inactivation.

Animals↗
PubMed1978

Gilles de la Tourette syndrome: clinical and genetic studies in a midwestern city.

Clinical and genetic observations of Gilles de la Tourette syndrome were carried out on members of 14 families from the Minneapolis area. An unusual number of the families were of Jewish and other Eastern European ancestry, and in all but one of these families multiple members were affected. These observations parallel our earlier findings based on 21 families from the New York City area. Together with recent evidence indicating relative instability of a specific enzyme in some patients, these observations suggest that there is a genetically determined form of Gilles de la Tourette syndrome.

Adolescent↗
PubMedDate not supplied

The prenatal detection of the fragile X chromosome: review of recent experience.

The fragile X chromosome has been identified in specimens from 17 male and 10 female fetuses in 11 laboratories throughout the world, obtained from at least 79 fetuses at increased risk for the fra(X) syndrome. Of these, 19 were confirmed, 6 were pending, 1 was negative and 1 could not be confirmed. Twenty-five of the 79 cases were studied in our laboratory (Institute for Basic Research [IBR]) and resulted in fra(X) demonstration in specimens from 3 male and 5 female fetuses. All 3 males and 2 of the 5 females have been confirmed. When amniocytes from the two confirmed female fetuses were exposed to FUdR after culturing in Chang medium, fra(X) frequencies were virtually negative indicating that Chang medium should not be used in fragile X studies at least when FUdR is used to induce fragility. Finally, amniocytes from a fra(X) male fetus studied in 3 different laboratories exhibited strikingly different frequencies. To date, we have experienced no false-positives or negatives, but the latter case was controversial. It is recommended that laboratories undertaking fra(X) prenatal detection use a combination of at least two different proven induction systems as well as complementary DNA marker studies to prevent false negative diagnosis.

Amniocentesis↗