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Biomedical subjects

U Sancken

Publications and source records attributed to U Sancken.

7 recordsLinked to original sources

The effect of thermal instability of intact human chorionic gonadotropin (ihCG) on the application of its free beta-subunit (free beta hCG) as a serum marker in Down syndrome screening.

The kinetics of free beta hCG concentrations were measured in 30 maternal whole blood samples from second-trimester pregnancies during 72 h incubation at 3, 20, and 30 degrees C. Dissociation of intact hCG (ihCG) was undetectable at 3 degrees C and produced a more than 20 per cent increase of free beta hCG at 20 degrees C and a more than 100 per cent increase at 30 degrees C. hCG dissociation at 30 degrees C was not reduced by a protease inhibitor (sodium iodoacetate) and also occurred in purified hCG dissolved in a protease-free incubation medium. These results were reproduced under conditions of sample transport by post at different environmental temperatures. In conclusion, reliable free beta hCG assessment requires that the specimen be kept cool from vene puncture until assay or completely other transport strategies have to be considered. Evaluation of free beta hCG as an effective marker in prenatal Down syndrome screening must be reconsidered from this aspect.

Blood Specimen Collection

Prenatal detection of X-linked ichthyosis by maternal serum screening for Down syndrome.

Maternal serum unconjugated oestriol (uE3) was measured in 15,375 pregnancies during 2 years of second-trimester risk assessment for Down syndrome using biochemical markers. Very low levels of uE3 (< 0.1 MOM) were detected in 22 serum samples (0.14 per cent). Very low uE3 was associated with an adverse outcome in 13 pregnancies including fetal death and miscarriage (N = 11) anencephaly (N = 1), and Meckel-Gruber syndrome (N = 1). Dry scales on the skin appeared in the first year of life in four boys. From dermatological diagnosis, prenatal uE3 levels, and pedigree analysis, it is concluded that at least 5 in approximately 7500 male births in the study population are affected by steroid sulphatase deficiency, which is the biochemical defect in X-linked ichthyosis. Very low uE3 levels in the second trimester are indicative of this disease in pregnancies with normal ultrasound findings.

Down Syndrome

[Prenatal risk index for fetal Down's syndrome with serum markers. Comment on the contribution by R. Benz, U. Müller, M. Krahner-Pilat, S. Wagner-Geuder, R. Terinde: Serum screening for Down's syndrome in women less than 35 years of age with an age-independent index].

5 years ago, maternal serum markers have been established for individual risk estimation of fetal Down syndrome. Recently Benz et al. presented an arbitrary age-independent risk index. Compared to the commonly applied statistical approach a 20% increase in detection rate was obtained by using the index (85% versus 65%). We recalculated data from 19,333 prospectively investigated pregnancies without trisomy 21 and 57 pregnancies with fetal Down syndrome using the proposed risk index. At the corresponding false-positive rate (7.9%) the age-independent detection rate was only 56%. This result indicates that the sensitivity cannot be increased by the Ulm index, when compared to statistical methods of risk estimation.

Biomarkers

[Martin-Bell syndrome. Improved possibilities for molecular genetic diagnosis].

In a former molecular segregation analysis of fra x mental retardation in 27 families at risk we had used marker gene probes with a relatively high recombination fraction. Thus, the resulting risk for a false diagnosis was comparatively high. To diminish this risk, all families were reanalyzed with the newly invented and more closely linked gene probes RN1A, VK23B, VK21C and U6.2. Using these probes as molecular markers we performed Southern hybridization experiments. The remaining diagnostic risk due to recombination events could be reduced to 2% up to 20% compared to preanalysis. The portion of informative families (91%) is in good agreement with the expected cumulative heterozygosis frequency of 93.4% for all 4 markers investigated. This high frequency and the very low remaining risk for a false diagnosis therefore enable a far more precise molecular diagnostic of the Martin-Bell-syndrome.

Abnormalities, Multiple

Maternal serum placental growth hormone and insulinlike growth factor binding proteins 1 and 3 in pregnancies affected by fetal aneuploidy and other abnormalities: implications for prenatal diagnosis of trisomy 21.

In the present study, we determined circulating serum levels of human placental growth hormone (hPGH) and insulinlike growth factor binding proteins 1 and 3 (IGFBP-1 and IGFBP-3) using two-site radioimmunoassays during the gestational midtrimester of pregnancies affected by chromosomal disorders with the aim of identifying potential marker substances that might have a significant discriminative and predictive value for prenatal diagnosis of fetal chromosomal aberrations and of organ malformations such as neural-tube defect. Our results show that the maternal serum levels of hPGH were significantly elevated in pregnancies affected by chromosomal anomalies or organ malformations as compared with controls. The distribution of IGFBP-1 concentrations for all experimental groups except trisomy 21 were closely similar to the normal population. IGFBP-3 decreased slightly in pregnancies affected by Down syndrome. These findings suggest that hPGH may be useful as an additional marker in prenatal screening for Down syndrome.

Adolescent