Search PubMed⌕ Search

Biomedical subjects

J Philip

Publications and source records attributed to J Philip.

At least 91 records · Page 5Linked to original sources
PubMed1993

Prenatal diagnosis by in situ hybridization on uncultured amniocytes: reduced sensitivity and potential risk of misdiagnosis in blood-stained samples.

Maternal cell contamination was assessed in 18 macroscopically blood-stained amniotic fluid samples from male fetuses. The samples were analysed by double-target fluorescent in situ hybridization (ISH) with Y and X chromosome-specific probes. The only sample with an aberrant karyotype (47,XY, + 18) was also analysed by hybridization with a chromosome 18-specific probe. An interpretation of extensive maternal cell contamination was made in two samples, one of which was the sample with trisomy 18. ISH with the chromosome 18-specific probe on this latter sample showed that the sensitivity of the ISH method for chromosome enumeration of uncultured amniotic fluid samples may be reduced in blood-stained samples. It was calculated that by using ISH for chromosome enumeration of the two extensively contaminated samples, a case of trisomy 21 might have been overlooked in both samples, while a case of trisomy 18 might only have been overlooked in one of the samples. It is concluded that ISH should not be used for chromosome enumeration of uncultured amniotic fluid samples that are macroscopically blood-stained without further technical developments.

Amniotic Fluid↗
PubMed1993

Cytogenetic analysis of 2928 CVS samples and 1075 amniocenteses from randomized studies.

We report cytogenetic results from a randomized Danish chorionic villus sampling (CVS) and amniocentesis (AC) study including 2928 placental and 1075 amniotic fluid specimens processed in the same laboratory. The results are presented in groups comparing CVS with amniocentesis and transabdominal (TA) CVS with transcervical (TC) CVS as randomized. More abnormalities and more ambiguous diagnostic problems were found in placental tissues than in amniotic cells. There were no diagnostic errors and no incorrect sex predictions. Mosaicism was detected in 1 per cent of all cases of CVS (discordancies included). When confirmation studies were done, 90 per cent were found to be confined to the placenta. Eight cases (0.7 per cent) of mosaicism/pseudomosaicism were seen in amniotic fluid specimens, and two cases of five with confirmation studies were confirmed in the fetus. The rate of mosaicism/pseudomosaicism in CVS and AC specimens differed (p < 0.05). The rate of pseudomosaicism in cultures of villi and amniotic fluid cells was 0.5 and 0.6 per cent, respectively. Single-cell aneuploidy was observed in 1.8 per cent of villi and 1.4 per cent of amniotic fluid cell specimens. Maternal cell contamination (MCC) was seen more often after TC sampling (4.5 per cent) compared with TA sampling (1.5 per cent), but posed no problems in interpretation. Compared with the processing of cultured specimens, the short-term method of preparation of villi in our laboratory doubled the technicians' workload. For practical and economic reasons we have ceased the routine use of short-term preparations.

Amniocentesis↗
PubMed1993

Rapid detection of numerical aberrations of chromosomes 13, 18 and 21 in chorionic mesenchymal cells.

We have devised and evaluated a rapid screening method for the detection of numerical aberrations of chromosomes 13, 18 and 21 in chorionic villus cells. We used non-radioactive in situ hybridization (ISH) with three chromosome-specific probes on overnight-attached mesenchymal cells from chorionic villi. A blind study was performed of 47 karyotypically normal samples, one triploid sample, two samples trisomic for chromosome 21, and two samples from a fetus with putative mosaicism (46/47, +21). All samples were hybridized with the chromosome 18- and 21-specific probes. Thirty samples were additionally hybridized with the chromosome 13-specific probe. The test could be completed within 3-4 days of sampling. In samples disomic with respect to the probed chromosomes, an average of 2 per cent (range 0-9 per cent) had three hybridization signals. By contrast, in the samples trisomic for the probed chromosome(s), 57 per cent (chromosome 13), 51 per cent (chromosome 18), and an average of 74 per cent (55-86 per cent) (chromosome 21) of the nuclei exhibited three signals. In the putative mosaic samples, the number of nuclei with three chromosome 21-specific signals ranged from 41 to 69 per cent. We conclude that this technique rapidly and clearly distinguishes between normal and trisomic/triploid samples, and consequently may be of use in future prenatal diagnosis.

Chorionic Villi↗
PubMed1993

Transabdominal chorionic villus sampling in the second and third trimesters of pregnancy: chromosome quality, reporting time, and feto-maternal bleeding.

Transabdominal chorionic villus sampling (TA-CVS) was performed in 210 pregnancies from 13 to 38 weeks using a double-needle technique. The sampling success was comparable to first-trimester TA-CVS and the diagnostic success rate was 98.2 per cent for the short-term technique and 99.3 per cent for cultured villi. Two fetuses could not be karyotyped. We found the chromosome quality to be similar to that in the first trimester, comparing the number of G-bands and other chromosome attributes. There were no unintended losses in a group (n = 142) with no sonographic abnormality, except for one death in utero at 38 weeks, 20 weeks after sampling. Chromosomal aberrations were seen in 19 per cent of cases with abnormal sonograms (n = 58). One cases of a discordant karyotype was found (false-negative prediction of Down's syndrome by the short-term preparation). There were no cases of fetal demise due to feto-maternal bleeding. It is suggested that double-needle TA-CVS in advanced pregnancies combines the advantages of rapid karyotyping of chromosomes of good quality and low risk for the fetus, and seems to be easier to practise and is probably safer than cordocentesis.

Chorionic Villi Sampling↗
PubMed1993

Filtration and recirculation of early amniotic fluid. Evaluation of cell cultures from 100 diagnostic cases.

Due to the low cell concentration, cultures from early amniotic fluid specimens usually require 2-3 weeks in culture prior to karyotyping. The purpose of this study was to evaluate the culture quality of amniotic fluid cells from early pregnancy, obtained by a new filter technique. The hypothetical advantage of the technique was that the increased cell yield might reduce the culture time before karyotyping. Culture quality was assessed by the number of colonies, the percentage of colonies containing mitoses in filter and control cultures, and the culture time. The setting was a consecutive clinical trial. One hundred samples were obtained from ongoing pregnancies at 11-14 weeks of gestation (mean 12.8 weeks). By circulating a mean of 26 ml of amniotic fluid through a cell filter system leading the cell-free fluid back to the amniotic cavity, the cell yield was increased in the sample of 7 ml corresponding to the dead space of the filter system. The culture results were compared with control cultures from 5 ml samples drawn from the same pregnancies prior to recirculation. The cultures from the first flushing of the filter system yielded 2.6 times more colonies and in total 4.2 times more colonies were found in the three cultures grown from each filter sample when compared with the control cultures. Moreover, the filter cultures showed significantly more colonies with mitoses. The mean culture time was 8.0 days for the filter cultures, from which the karyotypes were analysed. The controls would have needed more time in culture to fulfil the diagnostic criteria for karyotyping. One case of 47,XY,+21 was found; the rest had normal karyotypes. We conclude that the filter technique improves the culture quality of early amniotic fluid samples and allows early arrest of the cultures.

Amniocentesis↗
PubMed1993

Anti-cardiolipin antibodies (IgG and IgA) in women with recurrent fetal loss correlate to clinical and serological characteristics of SLE.

AIM OF STUDY: We investigated to which degree IgG, IgA and IgM anti-cardiolipin antibodies (aCL) are associated in recurrent abortion or late fetal death with other signs of autoimmune disease and in particular SLE. MATERIAL AND METHODS: Serological variables typical of SLE and of the anti-phospholipid antibody syndrome were measured once eight to 16 weeks after the last fetal loss in 158 women with recurrent abortion or late fetal death; women with manifest autoimmune rheumatic disease were excluded. RESULTS: (1) Positive values, i.e. above the 99th percentile of reference material, of IgG aCL and IgA aCL were observed in 4% and 7%, respectively, whereas 26% had positive values of IgM aCL. (2) IgG aCL and IgA aCL but not IgM aCL correlated to anti-nuclear antibodies and to anti-double stranded DNA. (3) Anti-double stranded DNA, IgG aCL and IgA aCL but not IgM aCL correlated to previous occurrence of thrombosis. (4) ANA correlated to lower blood platelet concentrations and higher erythrocyte sedimentation rates. CONCLUSIONS: Women with recurrent abortion or late fetal death who have higher but not necessarily abnormally high levels of IgG aCL or IgA aCL constitute a group with increased occurrence of clinical and serological characteristics of SLE. We suggest that these women be kept under surveillance for future development of autoimmune disease especially SLE. The women with high IgM aCL constitute another group without these characteristics.

Abortion, Habitual↗
PubMed1992

Randomised comparison of amniocentesis and transabdominal and transcervical chorionic villus sampling.

We have compared three methods of prenatal diagnosis in two large obstetric centres in Denmark. Women were randomly assigned transabdominal (TA) chorionic villus sampling (CVS), transcervical (TC) CVS, or second-trimester amniocentesis (AC); women at high genetic risk were randomised between the two CVS groups only. Analysis of 45 epidemiological variables showed the three procedure groups to be similar at enrollment. All women were followed up until completion of pregnancy. Among 3079 women at low genetic risk total fetal loss rates were 10.9% for TC CVS, 6.3% for TA CVS, and 6.4% for AC (p < 0.001). More women had bleeding after the procedure in the CVS groups (p < 0.001), whereas more amniotic fluid leakage (p < 0.001) was reported after AC. No uterine infections occurred in any group. No case of oromandibular-limb abnormality was seen in the CVS groups, but 1 child in the AC group had aplasia of the right hand. The two CVS approaches were compared among 2882 women at low and high genetic risk who were found to have cytogenetically normal fetuses. Rates of unintentional loss after the procedure were 7.7% for TC CVS and 3.7% for TA CVS (p < 0.001; 95% Cl of difference 2.3-5.8%). At baseline ultrasound scanning after establishment of optimum sampling conditions, more TC than TA procedures (p < 0.001) were judged not to be feasible. We found that TA CVS allows better access to the placental site than TC sampling, is an easier skill to acquire, and has the potential that more villi can be aspirated when needed. The risk of fetal loss is similar after TA CVS and AC. However, losses after AC are at a later stage and are therefore more distressing. TA procedures remain the first choice for prenatal diagnosis. Since, in our hands, TC sampling carries a greater risk to the fetus, we have abandoned TC CVS in our two study centres.

Adult↗
PubMed1992

New rapid test for prenatal detection of trisomy 21 (Down's syndrome): preliminary report.

OBJECTIVE: To devise and evaluate a rapid screening method for detecting trisomy 21 (Down's syndrome) in samples of uncultured amniotic fluid cells. DESIGN: Non-radioactive in situ hybridisation with HY128, a 500,000 base pair yeast artificial chromosome probe specific for chromosome 21. Blinded study of 12 karyotypically normal amniotic fluid samples and eight samples trisomic for chromosome 21. SETTING: Cytogenetic and obstetric services at a tertiary referral centre, Copenhagen. MAIN OUTCOME MEASURES: Time necessary to complete the test. Proportion of cell nuclei containing two and three hybridisation signals in karyotypically normal and abnormal amniotic fluid samples. RESULTS: The test could be completed within three to four days after amniocentesis. In the normal samples a mean of 73% (range 61-82%) of the amniotic cell nuclei showed two hybridisation signals and 6% (0-18%) showed three signals. By contrast, among the trisomic samples 29% (19-38%) of the nuclei exhibited two signals and 48% (31-60%) showed three signals. CONCLUSION: The technique clearly distinguished between normal and trisomic samples. Prenatal diagnosis with in situ hybridisation with chromosome specific probes was fast and may make it possible to screen for selected, aneuploidies. However, the technique is still at a preliminary stage and needs further evaluation and refinement.

Amniocentesis↗
PubMed1992

[Non-radioactive in situ hybridization with chromosome-specific probes].

Non-radioactive in situ hybridization (ISH) is a relatively new and sensitive method for analysis of chromosome aberrations. ISH may be performed on metaphase spreads or directly on interphase cells. By means of ISH, the so-called probes are bound to well-defined regions on the chromosomes of a cell. After a visualization process the probes and thus indirectly the chromosome regions may be observed in a microscope. Chromosome-specific probes become bound to chromosomal DNA segments which are specific for certain groups of chromosomes or only for a single chromosome. The chromosome-specific probes may be subdivided into 1) repetitive probes which are bound at or around the centromere, 2) painting probes which are bound to a certain chromosome in its entire extent or to a limited segment of this and 3) locus-specific probes which are bound to a single unique DNA sequence in the genome. ISH with chromosome-specific probes is of great scientific significance for chromosomal localization of genes. It is to be anticipated that this technique may be employed clinically e.g. in prenatal diagnosis and in the diagnosis of cancer and viruses.

Chromosome Aberrations↗
PubMed1992

Rapid prenatal diagnosis of trisomy 18 and triploidy in interphase nuclei of uncultured amniocytes by non-radioactive in situ hybridization.

Two biotinylated chromosome-specific DNA probes were used to quantify the number of chromosomes 18 and 1 in uncultured amniocytes. Thirty-three samples of uncultured amniocytes were hybridized with a chromosome 18-specific DNA probe. Uncultured cells from two of the 33 samples were also hybridized with a chromosome 1-specific probe. Thirty of the samples were disomic with respect to chromosome 18; two samples were trisomic with respect to chromosome 18, and one sample was trisomic with respect to chromosomes 1 and 18. The two cases of trisomy 18 and the single case of triploidy were identified on uncultured cells within 48-72 h after amniocentesis. They were found among five samples from pregnant women who had amniocentesis because of an ultrasonographically identified fetal malformation. A trisomic karyotype could be diagnosed with certainty in uncultured amniocytes because the majority of the responding nuclei exhibited three hybridization signals. In normal cells, the majority of nuclei exhibited two signals. In no cases was there discordance between the genotype as predicted by in situ hybridization and that determined by cytogenetic analysis.

Amniotic Fluid↗
PubMed1992

Genetic amniocentesis at 7-14 weeks of gestation.

Genetic amniocentesis performed at 7-14 weeks of gestation was studied in a series of 138 patients of whom 50 wanted termination of pregnancy (less than or equal to 12 weeks). The material for analysis consisted of 132 samples due to two sampling failures and four samples being handled incorrectly. Forty-eight samples (36 per cent) were taken at 7-12 weeks of gestation, mainly transvaginally (36/48: 75 per cent). The success rate of culture and karyotyping increased with the duration of pregnancy, but was only satisfactory from week 11 onwards. The time until harvest was then 14-15 days. The transvaginal approach is easy to perform and was accepted by the women, but we experienced bacterial or fungal overgrowth in 17 per cent of these samples, whereas no infection occurred in the samples taken transabdominally (n = 96). We conclude that genetic amniocentesis is feasible from week 11, but further studies concerning side effects, especially focusing on the procedure-related abortion risk, should be carried out before early amniocentesis is routinely applied.

Abdomen↗