Rapid detection of aneuploidies by microsatellite and the quantitative fluorescent polymerase chain reaction.

Several studies have been performed to assess the diagnostic value of using small tandem repeat (STR) markers and quantitative fluorescent polymerase chain reaction (QF-PCR) assays for the rapid detection of aneuploidies involving chromosomes 21, 18, 13 (Mansfield, 1993; Pertl et al., 1994, 1996; Adinolfi et al., 1995a).

Diagnosis of chromosomal aneuploidies using quantitative fluorescent PCR.

The incidence of chromosomal abnormalities in liveborn infants has been established to be about 1 in 170 newborns (1). The most frequent chromosomal anomalies are aneuploidies involving chromosomes 21,18,13, and both sex chromosomes. Prenatal diagnosis of chromosomal disorders is performed by conventional cytogenetic analysis of fetal cells collected by amniocentesis, chorionic villus sampling, or fetal blood sampling.

Quantitative fluorescence polymerase chain reaction for the rapid prenatal detection of common aneuploidies and fetal sex.

Objective: We have developed a quantitative fluorescence multiplex polymerase chain reaction assay for the rapid detection of sex and aneuploidies involving chromosomes 21, 18, and 13.

Study Design: Samples of deoxyribonucleic acid (n = 85) extracted from amniotic fluid, fetal tissues, and blood were investigated by multiplex polymerase chain reaction amplification of polymorphic small tandem repeat markers specific for chromosomes 21, 18, 13, and X.

Results: Quantitative analysis of the polymerase chain reaction products allowed us to distinguish between normal samples and samples with autosomal trisomies while sexing was performed simultaneously.

First trimester prenatal diagnosis using transcervical cells: an evaluation.

Human trophoblastic cells can be retrieved by minimally invasive procedures from the endocervical canal between between 6 and 15 weeks gestation. The incidence with which fetal cells can be detected in transcervical cell (TCC) samples varies according to the method of collection and the molecular techniques employed for their identification. Fluorescence in-situ hybridization (FISH) and polymerase chain reaction (PCR) assays have been successfully used to detect aneuploidies and Y-derived DNA sequences in TCC samples obtained from male fetuses.

Prenatal detection of Hb mutations using transcervical cells.

Prenatal diagnoses were performed on six selected pairs of parents known to be carriers of Hb mutations by testing transcervical cells (TCCs) retrieved, prior to chorionic villus sampling (CVS), by aspiration of the cervical mucus from the pregnant mothers at 10-12 weeks of gestation. A concordance between the results of testing chorionic villus cells and isolated clumps of trophoblastic cellular elements was observed in four of the six cases.

Prenatal detection of fetal aneuploidies using transcervical cell samples.

In the course of an investigation aimed at detecting the presence of trophoblastic cells in the endocervical canal of pregnant women between 7 and 17 weeks of gestation, several cases of aneuploidies were observed using a fluorescent in situ hybridisation (FISH) assay. The cases include fetal chromosome 21 and 18 trisomies, triploidy and sex chromosome aneuploidies. The results were confirmed by testing placental tissues obtained after termination of pregnancy (TOP).

Rapid detection of trisomies 21 and 18 and sexing by quantitative fluorescent multiplex PCR.

Aneuploidies involving chromosomes 21, 18, 13, X and Y account for over 95% of all chromosomal abnormalities in live-born infants. Prenatal diagnosis of these disorders is usually accomplished by cytogenetic analysis of amniotic or chorionic cells but this is a lengthy procedure requiring great technical expertise. In this paper, we assess the diagnostic value of using a quantitative fluorescent polymerase chain reaction (PCR) suitable for the simultaneous and rapid diagnosis of trisomies 21 and 18 together with the detection of DNA sequences derived from the X and Y chromosomes.

Immunohistochemical characterization of cells retrieved by transcervical sampling in early pregnancy.

Trophoblastic cells can be retrieved from the endocervix and the lower uterine segment in early pregnancy by aspiration or lavage (Rodeck et al., 1995). The feasibility of using this technique for prenatal diagnosis depends on how frequently fetal cells can be retrieved and whether such cells can be purified from the predominant maternal cell population.

Isolation of fetal cells from transcervical samples by micromanipulation: molecular confirmation of their fetal origin and diagnosis of fetal aneuploidy.

Transcervical cell (TCC) samples have been shown to contain fetal cells amenable to molecular analysis. However, the presence of 'contaminating' maternal cells limits their use for prenatal diagnoses. In this report we show that clumps of fetal cells can be isolated from transcervical samples by micromanipulation and tested by fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR).

Detection of fetal cells in transcervical samples and prenatal diagnosis of chromosomal abnormalities.

Transcervical samples collected by lavage, aspiration, and cytobrush from women between 6 and 13 weeks of gestation were tested for the presence of fetal cells using fluorescence in situ hybridization (FISH) with probes for chromosomes X, Y, 1, and 21, and by polymerase chain reaction (PCR) amplification of DNA sequences derived from chromosomes X, Y, and 21. With a few exceptions, a good correlation was observed between the results of sexing the fetuses using FISH or PCR on transcervical cell (TCC) samples retrieved by lavage and those obtained by testing fetal (placental) tissue. In a comparative study between TCC samples collected by lavage or cytobrush, the sex of the fetus was correctly diagnosed by PCR amplification of a Y-derived DNA sequence.

Detection of trophoblast cells in transcervical samples collected by lavage or cytobrush.

Objective: To compare two methods of obtaining fetal cells from the endocervical canal for prenatal diagnosis during the first trimester: lavage with physiologic saline, and the endocervical passage of a cytobrush.

Methods: Fetal cells were identified morphologically using conventional and immunohistochemical staining. Y-specific sequences were detected using polymerase chain reaction (PCR) and fluorescent in situ hybridization.

Rapid detection of selected aneuploidies by quantitative fluorescent PCR.

Selected aneuploidies can be rapidly diagnosed by the analysis of fluorescent polymerase chain reaction (PCR) products of chromosome-specific and highly polymorphic small tandem repeats (STRs). The quantitative STR patterns obtained from samples of normal individuals are markedly different from those seen when patients with aneuploidies involving chromosome X, or trisomies of chromosomes 21 and 18, are tested. For example, while samples from normal subjects--tested with a chromosome 21-derived STR (D21S11)--show two fluorescent PCR peaks with similar activities in a 1:1 ratio, the analysis of samples from patients with trisomy 21 reveals the presence of either three peaks (ratio 1:1:1), or two peaks with a ratio of 2:1.

Molecular evidence of fetal-derived chromosome 21 markers (STRs) in transcervical samples.

Transcervical cells (TCCs), collected by flushing or aspiration at 8-13 weeks of gestation, were analysed for the presence of fetal-derived DNA sequences. DNA extracted from maternal peripheral blood, TCC samples, and placental tissue was amplified by the polymerase chain reaction (PCR) to detect small tandem repeat (STR) markers specific to chromosome 21. STR products of fetal origin could be clearly observed in four TCC samples.

Composition of the coagulant polysaccharide fraction from Strychnos potatorum seeds.

The composition of the coagulant polysaccharide fraction from Strychnos potatorum seeds is described. This fraction comprises a 1:1.7 mixture of a galactomannan and a galactan.

FISH detection of trisomy 21 in interphase by the simultaneous use of two differentially labelled cosmid contigs.

Techniques have been reported in which fluorescence in situ hybridisation (FISH) and cosmid probes are used to detect trisomy 21 (and other abnormalities involving chromosomes X, Y, 13, and 18) on uncultured amniocytes. However the detection rate of trisomy 21 is lower than for the other anomalies owing to a larger number of uninformative results and false negatives. We report the simultaneous use of two differentially labelled cosmid contigs to improve the detection rate of trisomy 21 on uncultured amniocyte samples thus allowing the prenatal diagnosis of Down's syndrome even if only few labelled nuclei are available.

Rapid molecular method for prenatal detection of Down's syndrome.

We have evaluated a rapid method that allows prenatal detection of Down's syndrome in less than 24 hours. DNA from uncultured amniotic fluid, fetal blood, and tissue samples was amplified with the small tandem repeat (STR) marker D21S11. Quantitative analysis of fluorescent STR products with evaluation of their sizes provided clear evidence for trisomy 21.

Triterpenoid oligoglycosides from Chionodoxa luciliae.

Four minor novel oligoglycosides of triterpenes having a lanostane-type skeleton were isolated from the bulbs of Chionodoxa luciliae. The C30 skeleton of the aglycones has been found for the first time in Liliaceae and can be considered the metabolic precursor of the C29 eucosterol skeleton.