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Biomedical subjects

M J Mahoney

Publications and source records attributed to M J Mahoney.

16 recordsLinked to original sources
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↗
PubMed1978

A case of short rib polydactyly.

A patient with neonatal dwarfism had many characteristics of the Majewski syndrome, except for a cleft lip and abnormalities of internal organs. Absence of these anomalies and presence of more severe pathological changes in bone suggest either a wider spectrum for this disorder or a separate entity.

Dwarfism↗
PubMed1976

Inheritance in protoporphyria. Comparison of haem synthetase activity in skin fibroblasts with clinical features.

The activity of haem synthetase, the enzyme which chelates iron to protoporphyrin to form haem, was measured in cultured skin fibroblasts of children with protoporphyria and their parents from three families. In each family, one parent had deficient haem synthetase activity (3-0-11-1 pmol protohaem formed/mg protein/h) when compared to values in eight non-porphyric controls (means 24-9, range 13-7-51-5). The level of activity in the three parents was similar to that in their affected children. In two families the parent with deficient activity was also thought to be the carrier of the abnormal gene, as judged from a history of photosensitivity and analysis of erythrocyte protoporphyrin concentrations, but in the third family the pattern of inheritance could not be determined from these criteria. The activity of delta-aminolaevulinic acid synthetase was normal in cultured fibroblasts from the protoporphyric children and their parents, excluding a generalised defect in haem-pathway enzymes. These results support the premise that deficient haem synthetase activity, inherited in an autosomal dominant patter, is the primary defect in protoporphyria.

Adolescent↗
PubMed1976

Organic acidemias.

Inherited organic acidemias are a group of metabolic disorders currently being described and investigated as gas-liquid chromatography is applied to unexplained diseases of infancy and childhood. Common clinical presentations include attacks of ketoacidosis, unexplained metabolic acidosis, failure of normal development, seizures, and other neurologic abnormalities. Hyperglycinemia, hyperammonemia, and hypoglycemia are other laboratory findings frequently present. Diagnosis depends on examination of urine, and sometimes blood, by gas-liquid chromatography to measure concentrations of organic acids and organic acid derivatives. Prognosis in many cases is excellent if diagnosis is made promptly and the metabolic acidosis can be reversed. Recovery from neurologic deficits has frequently been seen. Long-term therapy is generally dependent on restricting precursors of the toxic organic acid which builds up as a consequence of the enzyme deficiency. If there is some enzyme activity retained or if alternate metabolic pathways exist, success with therapy is likely.

Acidosis, Renal Tubular↗
PubMed1975

Prenatal therapy of a patient with vitamin-B12-responsive methylmalonic acidemia.

Methylmalonic acidemia due to deficient synthesis of 5'-deoxyadenosylcobalamin was discovered in a mid-term fetus by culture of amniotic-fluid cells. Elevated concentrations of methylmalonic acid were also found in amniotic fluid and maternal urine. Treatment during the last nine weeks of gestation with large doses of vitamin B12 given to the mother reversed the increasing maternal excretion of methylmalonic acid, which was 23 mug per milligram of creatinine at 31 weeks' gestation. Just before delivery, the mother was excreting 5 mug, two to three times normal. At birth the methylmalonic acid content of the baby's urine (67 mug per milligram of creatinine) and serum (2.0 mug per milliliter) was only moderately elevated, and serum vitamin B12 concentration was very high. Acid levels rose in serum and urine in response to oral protein loading, but subsided after vitamin B12 administration. The infant is developing normally on a restricted protein diet alone at present. Prenatal therapy of methylmalonic acidemia is possible with large amount of vitamin B12 administered to the mother.

Amino Acid Metabolism, Inborn Errors↗
PubMed1975

Fetal blood drawing.

A small sample of fetal blood suitable for studies of haemoglobin synthesis was obtained from a placental vessel under endoscopic visualisation in 23 of 26 patients in whom the procedure was attempted prior to second-trimester abortion. Fetal blood loss, calculated in 23 cases, was between 0-2 ml. and 2-5 ml., and fetal blood-volume depletion varied from 0-5% to 15%. No short-term ill-effects were demonstrated in mother or fetus in any of 16 patients in whom the injection of aborti-facient was postponed for between 16 and 24 hours after the procedure.

Abortion, Therapeutic↗
PubMed1975

Studies of methylmalonyl coenzyme A carbonylmutase activity in methylmalonic acidemia. I. Correlation of clinical, hepatic, and fibroblast data.

Methylmalonyl-CoA carbonylmutase (mutase) activity was measured in fibroblast extracts from 15 patients with methylmalonic acidemia and in extracts of postmortem tissues from 6 of these children. Propionate oxidation and synthesis of 5-deoxyadenosylcobalamin (AdoCbl, the vitamin B12 coenzyme that is part of the mutase holoenzyme) were measured in intact fibroblasts. Mutase activity was low in the absence of added AdoCbl in fibroblast extracts from both control subjects and patients. When the assay included supplemental AdoCbl, mutase activity increased in the control subjects (to 24.0 pmol succinate/mg protein/min) and in extracts from eight of the patients (20.8 pmol/mg protein/min), but showed almost no change in extracts from the other seven patients (0.16 pmol/mg protein/min). We have defined the eight fibroblast lines that showed normal mutase activity in the presence of AdoCbl as "responsive lines" and the other seven lines as "nonresponsive." In the liver or kidney extracts of postmortem tissues, mutase activity responded to AdoCbl supplementation if fibroblast mutase activity from that patient had responded, and failed to respond if fibroblast activity failed to respond. Mean propionate oxidation in intact fibroblasts was much higher in control lines than in either responsive or nonresponsive lines (0.728 vs 0.097 vs 0.080 nmol CO2/10(6) cells/hr, respectively). AdoCbl synthesis was normal (0.27 pg AdoCbl/mg cells wet weight) in nonresponsive fibroblasts but was undetectable (less than 0.005 pg/mg cells) in the responsive lines. Thus, the deficiency of mutase activity in responsive fibroblast lines is due to the failure to synthesize significant amounts of AdoCbl, whereas the deficiency in nonresponsive lines is due to some other abnormality, presumably a defect in the mutase apoenzyme.

Animals↗