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S Kerber

Publications and source records attributed to S Kerber.

81 records · Page 5Linked to original sources
PubMed1992

Chromosomal mosaicism in prenatal diagnosis: a problem still unsolved.

The problems in differentiating chromosomal mosaicism from pseudomosaicism after amniocentesis and CVS are demonstrated in 6 cases. Two cases of true mosaicism (45, X/46, XX and 46, XY/47, XXY) were of clinical relevance. In both cases the aberrant cell line was less expressed in amniotic fluid cells than in fetal blood and cultivated fibroblasts. Two cases of pseudomosaicism (chromosome 2 and chromosome 10 trisomy) originated either from preexisting mutants or from in vitro mutations whereas a case of true chromosome 20 mosaicism indicated the possibility of a mosaic confined to a single fetal tissue. The problems of interpreting mosaicism after CVS is illustrated in a 45, X/46, XY case, in which the abnormal cell line was detectable only in extrembryonic tissue.

Amniocentesis↗
PubMed1990

[Early amniocentesis for cytogenetic diagnosis].

This study was designed to assess the feasibility of amniocentesis and amnion cell culture for prenatal diagnosis in early weeks of gestation (less than 15 weeks). Within a period of 18 months (1/88-6/89) 135 diagnostic amniocenteses were performed between 10 and 14 weeks and amniotic fluid was obtained in all instances. In all cases but one, sufficient cell cultures and chromosomal analyses were achieved. In the follow up, one miscarriage (0.7%) occurred, in two cases transient amniotic fluid leakage ceased spontaneously. All of the aforementioned complications were related to amniocenteses in weeks 11 and 12. The course of the continued pregnancies as well as fetal outcome were without any further complications. Comparing specimens of early and regular (16-18 weeks) amniocenteses in terms of time required for cell culture and karyotyping as well as the quality of chromosomal banding no significant differences were found. In contrast to maternal serum AFP which increased continuously, amniotic AFP levels could be seen to increase to a peak at 13 weeks' gestation but afterwards gradually declined. Based on these first experiences and results of early amniocenteses the specific problems of this method are discussed. In summary, it is concluded, that early amniocentesis between 12 and 14 weeks of gestation is feasible with regard to both the technique of amniotic fluid retrieval and the technique of chromosomal analysis. Early amniocentesis, therefore, could fill up the diagnostic gap between chorionic villi sampling (CVS) between 9 and 11 weeks of gestation and "classical" amniocentesis during weeks 16-18.

Amniocentesis↗
PubMedDate not supplied

Influence of dialysis procedure, membrane surface and membrane material on iopromide elimination in patients with reduced kidney function.

Haemodialysis for the elimination of contrast medium in patients with advanced renal failure is a common procedure. Even though sufficient elimination with the use of regular low-flux membranes is documented, large differences in results have been reported in prior investigations. We, therefore, compared Cuprophan and polysulfone dialysers with different surface areas to haemofiltration with different amounts of substitution fluid in 40 patients with compromised renal function after coronary angiography. Plasma iodine concentrations were measured by fluorescent excitation analysis. At constant blood flow rates of 200 ml/min, Cuprophan membranes with 1. 3 m(2) surface area had a clearance rate of 87 ml/min, whereas polysulfone membranes of comparable size displayed a significantly higher clearance rate of 147 ml/min. Polysulfone membranes with 1.8 m(2) surface area showed a small but insignificant increase in the iodine clearance (162 ml/min), while Cuprophan membranes displayed an increase in clearance rates (121 ml/min). Additional ultrafiltration led to a further increase in the plasma clearance of both membranes and reduced urinary iodine excretion. Haemofiltration was comparable to haemodialysis in terms of efficacy and thus represents an alternative method. Clearance of iopromide during haemodialysis with polysulfone membranes is higher than with Cuprophan membranes. Elimination rates can be further increased by additional ultrafiltration. Haemofiltration is comparable to haemodialysis regarding contrast medium elimination.

Biocompatible Materials↗
PubMedDate not supplied

Increased nuchal translucency, hydrops fetalis or hygroma colli. A new test strategy for early fetal aneuploidy detection.

OBJECTIVES: Nuchal translucency measurement of 3 mm or more (> or = 95th centile for gestation age), hydrops fetalis or hygroma colli between the 11th and 14th weeks of gestation is associated with a higher risk of fetal Down syndrome and other aneuploidies. So far, chromosome preparation of chorionic villi samplings (CVS) after short-term (or direct) culture is the only valid, reliable and rapid method of choice for the early detection of chromosomal aberrations. However, because of the placental mosaicisms detected after short-term culture, CVS has to be confirmed by a second method. Moreover, short-term villi preparation does not always provide a sufficient quantity and quality of metaphases to enable cytogenetic analysis. Unfortunately, a predicative cytogenetic result will be available only after long-term cultivation (usually after 1-2 weeks). An alternative rapid method, inexpensive and suitable for diagnosing autosomal trisomies, is the quantitative fluorescence polymerase reaction (QF-PCR) using different polymorphic small tandem repeats (STRs) on CVS-DNA. Therefore, it was the aim of the study to evaluate whether a new CVS test strategy could be employed in early pregnancies at high risk after the rapid detection of fetal chromosomal abnormalities by QF-PCR for chromosomes 13, 18 or 21 and sexing in conjunction with short-term chromosome analysis. MATERIALS: Nineteen CVS were chosen for QF-PCR detection of trisomy 21, 18 or 13 after an increased nuchal translucency measurement (> or = 95th centile for gestation age), a hydrops fetalis or a hygroma colli. The amelogenin locus of chromosomes X and Y (AMXY) were used for sexing. The QF-PCR results were compared with routine karyotyping after short- and/or long-term cultivation of CVS cells. RESULTS: An informative result was demonstrated in all analysed specimens. Nine CVS were diagnosed as a QF-PCR trisomy either for chromosome 21, 18 and 13. The pathological samples also included 4 cases of mosaicism where the normal cell line was not identified by QF-PCR. In 1 additional case with a normal QF-PCR result, short-term CVS chromosome analysis showed a mosaic trisomy 13, whereas longterm CVS culture revealed a normal karyotype. The malformed aborted fetus showed no clinical signs of trisomy 13, confirming the normal results obtained by QF-PCR and long-term CVS chromosome analysis. One pregnancy with a Turner syndrome was not identified by molecular analysis. CONCLUSIONS: This study showed that all early pregnancies with a clinically relevant autosomal trisomy could be detected prenatally in routine practice by QF-PCR. The combined use of both rapid methods - QF-PCR and short-term chromosome analysis - optimise the results by minimising the possibility of false-positive or false-negative findings. We believe that after verification of a pathological result obtained by two independent methods (QF-PCR and short-term CVS chromosome analysis), long-term villi cultivation is no longer necessary. However, in all cases with discrepancies, especially in samples with mosaic findings at short-term CVS cultivation, further studies are still necessary.

Chorionic Villi Sampling↗