Search PubMed⌕ Search

Biomedical subjects

C M Strom

Publications and source records attributed to C M Strom.

At least 37 records · Page 2Linked to original sources
PubMed1994

Reliability of polymerase chain reaction (PCR) analysis of single cells for preimplantation genetic diagnosis.

PURPOSE: We investigated the reliability of polymerase chain reaction (PCR) genotype analyses performed on single cells for the purposes of preimplantation genetic analysis. METHODS: We performed blind analysis of 130 single skin fibroblasts heterozygous for the delta-F508 mutation in the cystic fibrosis transmembrane regulator (CFTR) gene and 73 single skin fibroblasts from an individual heterozygous for the XbaI polymorphic site of the Factor VIII gene. RESULTS: Amplification was successful for 116 cells and 52 cells respectively and in all but one case (a CFTR analysis) both alleles were amplified. The incidence of diagnostic error was 1 out of 203 analyses or 0.0043. We conclude that PCR is a reliable method for determining the genotype of single cells for the purposes of preimplantation genetic analysis.

Alleles↗
PubMed1992

Double-blind, placebo-controlled crossover study of folinic acid (Leucovorin for the treatment of fragile X syndrome.

We conducted a randomized, double-blind, placebo-controlled crossover study of folinic acid therapy (dl-Leucovorin, 15 mg/day) or placebo for males with Fragile X (fra(x)) syndrome. Twenty-one patients were enrolled in the study. The treatment periods were 3 months in length. Patients were followed with chemistry panels and complete blood counts. No differences between placebo and treatment phases were noted in any laboratory parameter. Instruments to measure functioning were the Vineland Adaptive Behavioral Scales, Peabody Picture Vocabulary Test-Revised, Conners Parent and Teaching Rating Scales, the ADD-H: Comprehensive Teacher's Rating Scales (ACTeRS), and a questionnaire designed by the investigators. At the crossover point, 2 parents requested to withdraw from the study because they felt their children had made dramatic gains during the first half of the study and had lost those gains after the crossover point. Both parents had accurately predicted that their sons were receiving folinic acid during the first half of the study. However, no statistically significant differences could be demonstrated between the treatment and placebo phases of the study with any instrument when the results were averaged over the entire cohort. After the conclusion of the study, approximately one-half of the parents believed that their children had benefitted from the folinic acid therapy and elected to continue treatment. Thus far, no significant side effects have been noted from long-term folinic acid therapy so we are offering all Fragile X patients a 3-month trial of medication.

Adolescent↗
PubMed1992

Preconception and preimplantation diagnosis for cystic fibrosis.

Preimplantation diagnosis provides couples at high genetic risk the possibility of avoiding genetic disease without the need for prenatal diagnosis and selective abortion of the affected pregnancy. Following extensive background work on the reliability of genetic diagnosis in a single cell, we offered on a research basis preimplantation diagnosis to five couples at risk for offspring with the delta-F508 mutation (the major mutation causing cystic fibrosis). There was no detrimental effect from polar body removal on either fertilization or preimplantation development. Genetic analysis, undertaken in 22 polar bodies and 15 corresponding blastomeres, identified 21 embryos of which ten were transferred.

Biopsy↗
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

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

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

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↗
PubMed1985

Nonrandom association of a type II procollagen genotype with achondroplasia.

Achondroplasia is an autosomal dominant disorder that involves defective endochondral bone formation. Type II collagen is the predominant collagen of cartilage. We found a HindIII polymorphic site in the normal Caucasian population by using the type II procollagen gene probe pgHCol(II)A. The presence of this site yields a 7.0-kilobase (kb) band; its absence yields a 14.0-kb band. We found a significant deviation in genotype distribution and allele frequencies in a population of unrelated individuals with sporadic achondroplasia, compared with the normal control population. The HindIII genotype frequencies in 32 individuals with achondroplasia are 0.41 for the 7/7 genotype (controls, 0.08), 0.34 for the 7/14 genotype (controls, 0.54), and 0.25 for the 14/14 genotype (controls, 0.37). The apparent equilibrium excess of the "7" allele in individuals with achondroplasia may reflect either a predisposition for the mutation that causes achondroplasia or it could be the result of the achondroplasia-causing mutation. In either case, these findings suggest an association of the type II procollagen gene with achondroplasia.

Achondroplasia↗
PubMed1985

Structure of the type II collagen gene.

In summary, the exon/intron structure of the chicken type II collagen gene is identical with that of the chicken alpha 2(I) collagen gene and differs at only one known position from the human and mouse alpha 1(I) genes. However, the chicken type II gene is different from the chicken alpha 2(I) gene in that it is considerably shorter because of a much smaller average intron size and in that the G+C composition of the introns is much higher. The codon usage of the type II genes also shows characteristic differences. There is a single copy of the chick type II gene per haploid genome.

Animals↗
PubMed1985

Analysis of three restriction fragment length polymorphisms in the human type II procollagen gene.

Cloned genomic DNA sequences corresponding to various regions of the human type II procollagen gene were used to analyze the DNA from 78 normal volunteers. Southern hybridization experiments detected polymorphic HindIII, BamHI, and EcoRI sites. The presence of the polymorphic HindIII site results in a 7.0-kilobase (kb) band, and the absence of this site results in a 14.0-kb band. When present, the BamH1 polymorphic site yields a 4.8-kb band, and when absent, yields a 7.2-kb band. The presence of the EcoRI polymorphic site results in a 3.7-kb band, and its absence results in a 7.0-kb band. Each polymorphic site was mapped. Analyses of the data demonstrated that the sites are present in overall gene frequencies of .39 for HindIII, .04 for BamHI, and .02 for EcoRI. Gene frequencies of the polymorphic sites were also studied with respect to race. The polymorphic sites are present in a Hardy-Weinberg distribution in the study population. Study of an extended family demonstrated that the segregation of the HindIII polymorphic site is consistent with Mendelian inheritance.

Deoxyribonuclease BamHI↗