Search PubMed⌕ Search

Biomedical subjects

M J Mahoney

Publications and source records attributed to M J Mahoney.

At least 127 records · Page 7Linked to original sources
PubMed1982

Stage II ultrasound examination for the diagnosis of fetal abnormalities with an elevated amniotic fluid alpha-fetoprotein concentration.

Previous studies have indicated that patients with elevated levels of amniotic fluid alpha-fetoprotein (AFAFP) are at very high risk for fetal neural tube defects. Twenty-eight patients whose levels of AFAFP were greater than 3 standard deviations above the mean were evaluated with a Stage II ultrasound examination for detailed assessment of fetal anatomy. In 16 patients with AFAFP levels greater than 5 SD above the mean, six fetuses with open spina bifida were identified (37.5%). Moreover, in four fetuses in this group, the diagnosis was ventral wall defects (two with gastroschisis and two with omphalocele), and one fetus had multiple lethal anomalies. The other 5 patients had normal scans, and, with the exception of one patient who was delivered of a nondysmorphic stillborn infant at 28 weeks, all had normal infants at birth. Among the other 12 patients with AFAFP levels between 3 and 5 SD above the mean, there were only two adverse findings--an intrauterine death and an omphalocele. A Stage II ultrasound examination performed when AFAFP levels are elevated enables one to distinguish between conditions which are lethal or associated with significant impairment and those which are amenable to surgical procedures. Morphologically normal fetuses can also be identified. Since this diagnostic technique will allow salvage of many pregnancies that otherwise would be aborted, it should be an integral part of any alpha-fetoprotein screening program.

Abdominal Muscles↗
PubMed1982

Detection of hemophilia carriers during pregnancy.

The accuracy of hemophilia A carrier detection during pregnancy has been determined using combined measurement of VIII:CAg and VIIIR:Ag. These immunoassays detect determinants that are sufficiently stable in plasma that the assays could be done on frozen samples that had been obtained when women were seen for antenatal diagnosis studies (carrier women) or for routine prenatal care (controls). A linear discriminant was calculated that best separated the data for 32 normal women and 25 obligate carriers of the hemophilia gene. Twenty-three of 25 carriers (92%) and all 32 control women were correctly identified in this analysis. The overall classification accuracy (55/57, 96%) is comparable to that obtained by VIII:C and VIIIR:Ag measurements using freshly drawn blood samples in nonpregnant individuals. This study demonstrates that hemophilia A carriers can be detected during pregnancy with sufficient accuracy that the information may be used for genetic counseling.

Antigens↗
PubMed1981

Fetoscopy.

Explore the source record for details and available documents.

Biopsy, Needle↗
PubMed1981

Autosomal recessive inheritance of human mitochondrial carbamyl phosphate synthetase deficiency.

The mode of inheritance of hepatic mitochondrial carbamyl phosphate synthetase (CPS I) deficiency has not been established conclusively in the past. In this study, hepatic tissue obtained by percutaneous biopsy from all members of the immediate family of two girls affected with partial CPS I deficiency was assayed for CPS I, ornithine transcarbamylase (OTC), and arginase activities. Only values for CPS I activity differed significantly from those in controls. The two affected girls each had markedly reduced CPS I activities of about 6% of the control mean. Their brother had activity well within the normal range. Of greatest significance was the finding that both parents had activities below the 95% confidence limits in controls, and intermediate between the deficient values of the two girls and the control range. The father and mother had, respectively, 32% and 54% of mean control activity. These data indicate that CPS I deficiency is inherited as an autosomal recessive trait and that the two affected girls are homozygous for the mutant gene, their brother is homozygous for the normal allele, and the parents are heterozygous.

Adolescent↗
PubMed1980

Fetoscopy: an update.

Explore the source record for details and available documents.

Blood Specimen Collection↗
PubMed1980

Prenatal diagnosis of beta-thalassemias by amniocentesis: linkage analysis using multiple polymorphic restriction endonuclease sites.

In order to assess the applicability of multiple restriction endonuclease analyses of amniocyte DNA to the prenatal diagnosis of beta-thalassemias in general, we studied 12 consecutive couples at risk. DNA of both members of the 12 couples and a previous offspring of each was analyzed for the presence of 4 polymorphic restriction endonuclease sites: the Hpa I site 3' to the beta-globin gene, the Hind III site in the G gamma gene, the Hind III site in the A gamma gene, and the Bam HI site 3' to the beta-gene. Linkage disequilibrium between these sites and beta A or beta thal genes was not found, presumably due to the heterogeneity of beta thal genes. However, the high frequency of polymorphism at these sites allowed differentiation of beta A-bearing chromosomes from beta thal or beta S-bearing chromosomes in both members of 6 couples. In these couples, complete prenatal diagnosis by linkage analysis of amniocyte DNA would be possible. In the remaining 6 couples, beta A and beta thal chromosomes could be discriminated in one member. In about 50% of the pregnancies of these couples, exclusion of beta-thalassemia is possible by this analysis. These data suggest that when linkage analysis of polymorphic restriction endonuclease sites is carried out, prenatal diagnosis of beta-thalassemia states can be accomplished by amniocentesis alone in 75% of pregnancies at risk.

Amniocentesis↗
PubMed1979

Ultrasound in the diagnosis of congenital anomalies.

With high-resolution ultrasound equipment, it is now possible to diagnose certain fetal anomalies in the third trimester and in some cases before the twentieth week of gestation. During a 27 month period 2,548 ultrasound scans were performed in high-risk patients. An anomaly was diagnosed in 10 of 122 second-trimester patients who were at risk for recurrent fetal defects. Fetal deformity was also found in 26 third-trimester patients. Of the 2.8% of patients found to have polyhydramnios 18% were associated with various types of anomaly. With ultrasound it was possible to examine internal fetal anatomy and to identify abnormalities of the fetal cranium, spine, chest, abdomen, and limbs. These anomalies are reviewed here in detail. Based on ultrasonically derived information, second-trimester patients can be offered information concerning the status of their fetuses at risk genetically and physicians can better manage third-trimester patients with diagnosed fetal deformities.

Amniotic Fluid↗
PubMed1979

Prenatal diagnosis of classic hemophilia.

Prenatal diagnosis of classic hemophilia (hemophilia A) in mid-trimester was achieved by means of immunoradiometric assays for factor VIII on fetal plasma and amniotic-fluid mixtures obtained by fetoscopy. Samples were analyzed from six male fetuses at risk for severe hemophilia and from nine control fetuses for which fetoscopy was carried out to attempt prenatal diagnosis of other genetic disorders. The factor VIII coagulant-antigen values for the control (non-hemophilic) samples were 17 to 94, and the factor VIII related-antigen concentrations were 50 to 155 U per deciliter. Three of the fetuses at risk for hemophilia had factor VIII values in the control range, and these infants were normal at birth. The other three fetuses had low concentrations of factor VIII coagulant antigen but normal concentrations of factor VIII related antigen. These values and the diagnoses of severe hemophilia were confirmed with blood from the abortuses.

Amniotic Fluid↗
PubMed1979

Prenatal diagnosis of homozygous alpha-thalassemia.

A Vietnamese couple were both carriers of alpha-thalessemia-1. The woman had a first pregnancy terminated in the delivery of a hydropic fetus due to homozygous alpha-thalassemia. The couple requested prenatal diagnosis for the second pregnancy. The DNA obtained from cultured amniotic fluid cells was studied pregnancy. The DNA obtained from cultured amniotic fluid cells was studied by hybridization with globin cDNA in solution and on filters (Southern technique). Both analyses demonstrated no alpha-globin structural genes were present. Following termination of the pregnancy, the diagnosis was established by the presence of only hemoglobins Barts (gamma 4) and Portland (zeta 2 gamma 2) in the fetal blood.

DNA↗