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Y Verlinsky

Publications and source records attributed to Y Verlinsky.

At least 91 records · Page 5Linked to original sources
PubMed1992

Parthenogenetic activation of human oocytes by puromycin.

OBJECTIVE: Our objective was to obtain parthenogenetic activation of unfertilized human oocytes by puromycin and to try to use this procedure for cytogenetic purposes. SETTING: The setting was our IVF laboratory. METHODS: Eighty-two spare oocytes from 34 IVF patients were used. In the first series of experiments 39 unfertilized oocytes were cultured in medium containing 100, 50, or 10 micrograms/ml puromycin for 6 to 24 hr. After the appearance of pronuclei they were transferred to plain medium, further cultured, and cytogenetically analyzed. In the second series of experiments 43 oocytes were cultured for 5 to 10 hr in 10 micrograms/ml puromycin, transferred to plain medium, and fixed for cytogenetic analysis 2 hr after nuclear envelope breakdown. RESULTS: Ninety-one percent of the oocytes in the first experiment showed the presence of one or more nuclei. From the pronucleate oocytes additionally cultured in puromycin-free medium, 46% developed further to the metaphase of the first mitotic division or the two-cell stage and 54% remained arrested at the pronuclear stage. In the second experiment 88% of the treated oocytes showed pronuclei or had cleaved, and after withdrawal from puromycin 96% of the pronucleate oocytes entered mitosis. CONCLUSION: Puromycin induces haploid as well as diploid parthenogenesis in aged human oocytes. A 5- to 10-hr treatment of oocytes with 10 micrograms/ml puromycin yields the highest percentage of activation, and almost all parthenogenetically activated oocytes enter or develop beyond the first cleavage mitosis. Analysis of mitotic metaphase chromosomes from parthenogenetically activated human oocytes may be a promising new approach to preimplantation cytogenetics.

Cell Division↗
PubMed1992

Analyses of 95 first-trimester spontaneous abortions by chorionic villus sampling and karyotype.

PURPOSE: Our purpose was to determine the incidence of chromosomal aneuploidy in first-trimester pregnancy losses using chorionic villus sampling (CVS). STUDY DESIGN: All patients presenting for CVS with no fetal cardiac activity were offered CVS. RESULTS: Cytogenetic results were completed in 95 of 96 cases (99%). Eighty-three percent of the karyotypes were aneuploid. The 16 euploid fetuses had no excess of females. CONCLUSION: CVS is the most reliable method of determining the karyotype of spontaneously aborted fetuses. The incidence of aneuploidy is much greater than in previous reports that analyzed passed products of conception. CVS should be offered to women who present with first-trimester spontaneous abortions.

Abortion, Spontaneous↗
PubMed1992

Visualization of second polar body chromosomes in fertilized and artificially activated mouse oocytes treated with okadaic acid.

OBJECTIVE: Our objective was to develop a new reliable method for cytogenetic analysis of the chromosome set in second polar bodies (PBs) from one-cell-stage mouse embryos. SETTING: The study took place at the Reproductive Biology and Experimental Cytogenetics Laboratories. METHODS: Oocytes from F1 hybrid and T6/T6 mice were fertilized in vitro and artificially activated with ethanol. Zygotes, parthenogenetic embryos, and isolated second PBs were treated with 10 microM okadaic acid (OA) for 1-2 hr, further cultured in plain medium, and fixed. Chromosomal preparations were made and C-banded, and the number of chromosomes in second PBs and embryos was counted. RESULTS: OA-induced nuclear envelope breakdown in pronuclei as well as in second PB nuclei. Countable chromosome plates were obtained in 92-93% of second PBs treated 4-4.5 hr after activation. The T6 marker chromosome could easily be recognized in second PBs from T6/T6 mice. A haploid set of chromosomes was obtained in 18 of 19 isolated second PBs treated with OA 4-5 hr after activation. CONCLUSION: Treatment of second PBs with OA allows visualization of the PB chromosomes. Cytogenetic analysis of the second PB and the corresponding oocyte constitutes a new approach for the study of meiotic nondisjunction in experimental cytogenetics. The chromosomal study of isolated second PBs seems to be promising for clinical preimplantation cytogenetics.

Animals↗
PubMed1992

Term birth after midtrimester hysterotomy and selective delivery of an acardiac twin.

OBJECTIVE: Our aim was to determine whether hysterotomy and selective removal of an acardiac twin could improve the outcome of the "pump" twin. STUDY DESIGN: A literature and case review of the outcome of the acardiac twin malformation was performed. When an acardiac malformation was diagnosed at 19 weeks' gestation the patient was monitored with weekly ultrasonographic examinations. At 23 weeks' gestation, no blood flow could be demonstrated to the acardiac twin and it was thought that the continued presence of the acardiac twin posed a risk to the "pump" twin. A midtrimester hysterotomy was performed and the acardiac twin was delivered. RESULTS: After the midtrimester hysterotomy, the pregnancy progressed to term and a healthy female infant was delivered by elective cesarean section at 37 weeks' gestation. CONCLUSION: Midtrimester hysterotomy may be a useful intervention in cases of twinning when one fetus is a threat to the health of the other.

Adult↗
PubMed1992

Micromanipulation of gametes and embryos in preimplantation genetic diagnosis and assisted fertilization.

Recent advances in micromanipulation and biopsy of gametes and embryos have made it possible to develop new approaches for early genetic diagnosis and prevention of genetic disease and for treatment of severe male-factor infertility. Preimplantation diagnosis of a number of X-linked and autosomal recessive disorders has been performed, using polar body sampling and blastomere biopsy, coupled with polymerase chain reaction. Blastocyst biopsy has also been performed in human embryos; however, there has been no clinical application so far. Existing data have not shown any detrimental effect of micromanipulation and biopsy involved in the preimplantation development of the human embryo. The existing experience on micromanipulation of gametes (zona-opening procedures, subzonal sperm insertion, and sperm microinjection into the ooplasm) has also demonstrated the clinical usefulness in assisted fertilization, suggesting a possible selective application of various micromanipulation techniques and their combinations in male infertility.

Biopsy↗
PubMed1992

Decreasing risk of pregnancy loss following chorionic villus sampling. Elimination of transabdominal chorionic villus sampling during the ninth week of pregnancy.

Chorionic villus sampling (CVS) is a method of obtaining fetal cells in the first trimester of pregnancy for genetic analysis. The transcervical (TC) approach was the first technique to be widely used. In the National Institute of Child Health and Human Development collaborative study the absolute loss rate following CVS (the total number of spontaneous abortions and neonatal deaths following CVS) was 4%. More recently the transabdominal (TA) approach has been introduced. This study compares the loss rates for the two approaches at various gestational ages for three 6-month periods following the addition of the TA approach with each other and with the loss rates prior to the introduction of TA CVS. We found that the percentage of pregnancy losses following TA CVS during the ninth week of gestation (63-69 days) was consistently higher than for TC CVS performed at the same gestational age. The loss rate for TC CVS has steadily decreased since the introduction of TA CVS after remaining the same for the two years prior to the introduction of the TA approach. After minimizing the number of TA CVS performed during the ninth week of gestation, the overall loss rate during the most recent 6-month period has been reduced to 0.94%. We conclude that the lowest loss rate following CVS can be obtained if both the TA and TC methods are available, and that the number of TA procedures performed during the ninth week of gestation is minimized.

Abortion, Spontaneous↗
PubMed1991

Reliability of gender determination using the polymerase chain reaction (PCR) for single cells.

Contamination with extraneous DNA sequences is a frequent problem when performing PCR analysis of single cells. This report describes our experience with eliminating contaminating DNA sequences from PCR reagents for the purposes of gender identification. We have used amplification of Y-specific sequences to identify the gender of single human amniocytes. Female cells consistently showed no Y-specific bands but only 80% of male cells showed the expected intense Y-specific band. This phenomenon could lead to incorrect gender identification of single cells. We developed a technique of simultaneous amplification of X- and Y-specific sequences to prevent misdiagnosis because of failed PCR, which allows accurate preimplantation gender determination for women at risk for conceiving children with X-linked genetic diseases. We analyzed the gender of 141 consecutive single cells in a blinded manner without a single incorrect gender assignment.

Blastomeres↗
PubMed1990

Cytogenetic results of chorionic villus sampling: high success rate and diagnostic accuracy in the United States collaborative study.

Cytogenetic results of first-trimester chorionic villus sampling are reported from seven U.S. medical centers. For 6033 patients who had a successful chorionic villus sampling procedure, the rate for obtaining a cytogenetic diagnosis was 99.6% with the direct method, long-term culture, or both. There were no incorrect sex predictions and no diagnostic errors involving trisomies 21, 18, or 13, sex chromosome aneuploidies, or structural abnormalities. There were no cases of normal cytogenetic diagnosis followed by birth of a cytogenetically abnormal infant. Three cases of unusual aneuploidies (tetraploidy, trisomy 16, and trisomy 22) detected by the direct method only were not confirmed by cytogenetic follow-up. Mosaic cytogenetic abnormalities were observed in 0.83% of all cases in which chorionic villus sampling was done but were confirmed by amniocentesis or in fetal tissues in only 7 of 30 cases (23.3%). Maternal cell contamination occurred in 1.9% of long-term cultures, although this did not present any cytogenetic diagnostic difficulties. Overall, a very high degree of laboratory success and diagnostic accuracy was observed with either cytogenetic method, although fewer predictive errors were observed with the long-term culture method and none were observed when both methods were used.

Amniocentesis↗
PubMed1990

Ultrasonographic detection of the second-trimester fetus with trisomy 18 and trisomy 21.

Biparietal diameter/femur length ratio and nuchal thickness were found to be sensitive indicators for the prenatal detection of trisomy 18 and trisomy 21. A biparietal diameter/femur length ratio greater than 1.5 SD above the control mean correctly identified 5 of 11 (46%) fetuses with trisomy 21 and 3 of 4 (75%) fetuses with trisomy 18. Nuchal thickening (6 mm or more) correctly identified 5 of 12 (41%) fetuses with trisomy 21 and 2 of 4 (50%) fetuses with trisomy 18. The sensitivity and specificity of the biparietal diameter/femur length ratio in detecting either aneuploidy was 53% and 93%, respectively, whereas a thickened nuchal fold had a sensitivity of 44% and a specificity of 100%. The combined use of the two ultrasonographic measurements had an overall sensitivity of 81% and a specificity of 93%. Prospective ascertainment of these two trisomies appears warranted in low-risk populations.

Chromosome Aberrations↗
PubMed1990

Analysis of the first polar body: preconception genetic diagnosis.

In women who are heterozygous for a genetic disease, genetic analysis of the first polar body allows the identification of oocytes that contain the maternal unaffected gene. These oocytes can be fertilized and transferred to the mother without risk of establishing a pregnancy with a genetically abnormal embryo. We have demonstrated that removal of the first polar body has no effect on subsequent fertilization rates or embryonic growth to the blastocyst stage. We have developed a PCR technique to successfully analyze the PI type Z and PI type M genotypes of alpha-1-antitrypsin deficiency and applied this technique for a couple at risk for PI type ZZ alpha-1-antitrypsin deficiency. After standard IVF treatment to stimulate multiple follicle development, eight oocytes were aspirated transvaginally. Polar bodies were removed by micromanipulation from seven oocytes and fertilization occurred in six cases. PCR analysis was successful in five oocytes. One was PI type M, two were PI type Z and two were heterozygous MZ due to crossing over. Embryos from the two oocytes containing the unaffected gene (polar body PI type Z) were transferred in the same cycle 48 h after insemination. No pregnancy was established. The accuracy of the polar body diagnosis was confirmed by polymerase chain reaction (PCR) analysis of an oocyte that failed to fertilize.

Base Sequence↗
PubMed1987

Association of red cell spherocytosis with deletion of the short arm of chromosome 8.

Congenital spherocytic anemia is a common disorder, but in most cases the nature of the underlying membrane lesion is unknown and the genetic defect has not yet been unequivocally mapped to a chromosome. We studied two dysmorphic siblings with neurologic findings and hemolytic anemia. Clinical and laboratory findings in these two siblings were consistent with the diagnosis of congenital spherocytosis whereas both parents and two unaffected siblings were normal. The two affected children had an abnormal chromosomal complement as a result of a deletion of the short arm of chromosome 8 [(46,XX,del(8)(p11.1p21.1)]. These results suggest that a gene whose deletion results in a congenital spherocytic anemia phenotype resides on this region on the short arm of chromosome 8.

Chromosome Deletion↗
PubMed1986

Clastogen-induced chromosomal breakage as a marker for first trimester prenatal diagnosis of Fanconi anemia.

Using cultured trophoblast cells obtained by chorionic villus biopsy, we diagnosed Fanconi anemia (FA) in two pregnancies and excluded it in eight pregnancies at risk for the syndrome. Baseline chromosomal breakage and breakage induced by diepoxybutane (DEB) were analyzed. Increased breakage was used as a marker for the syndrome. Our results were unambiguous and provide a reliable method for prenatal detection of FA in the first trimester of pregnancy.

Anemia, Aplastic↗
PubMedDate not supplied

Polar body-based preimplantation diagnosis for X-linked disorders.

Preimplantation diagnosis for X-linked disorders has been performed predominantly by gender determination, which, however, leads to the discarding of 50% unaffected male embryos. In an attempt to identify X-linked mutation-free embryos for transfer, the present authors introduced preimplantation genetic diagnosis (PGD), using a sequential first and second polar body analysis, as an alternative to gender determination. This method was offered to eight couples at risk for having children with X-linked disorders, including haemophilia B, fragile-X syndrome (FMR1), myotubular myotonic dystrophy (MTMD), ornithine transcarbamylase (OTC) deficiency and X-linked hydrocephalus. The first and second polar bodies were removed following maturation and fertilization of oocytes in a standard IVF protocol and analysed using a multiplex nested polymerase chain reaction (PCR), involving testing for mutations simultaneously with linked markers. Overall, 13 PGD cycles were performed, resulting in the detection of 25 embryos with the predicted mutation-free maternal contribution; these embryos were transferred back to the patients in all cycles, yielding four clinical pregnancies. Four children were born following these pregnancies, including three unaffected and one with misdiagnosis as a result of allele dropout (ADO), which was predictable in the case of FMR1. Presented results demonstrate the clinical usefulness of the specific polar body testing for X-linked disorders as an alternative to PGD by gender determination.

Female↗