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Biomedical subjects

H L Levy

Publications and source records attributed to H L Levy.

At least 163 records · Page 9Linked to original sources
PubMed1981

Massachusetts Metabolic Disorders Screening Program. II. Methylmalonic aciduria.

Screening neonates for methylmalonic aciduria is part of routine screening for metabolic disorders in Massachusetts. The process of urine collection by the parent and transmitted to the central screening laboratory was described in a previous publication (Pediatrics 49: 825, 1972). The primary objective of screening for methylmalonic aciduria is to detect methylmalonic acidemia, an inherited organic acid disorder. During the most recent 5 1/2-year period when the sensitive fast blue B stain was used in the analysis, four infants with methylmalonic acidemia were detected among 293,535 screened. Additional infants and children who came to attention because of clinical illness or family study also could be readily detected. Prior to this period, 325,634 neonates had been screened with the aniline-xylose method, which proved to be not sensitive enough for the identification of methylmalonic aciduria. Some affected infants have responded well to therapy and are clinically normal while two have shown poor biochemical response and are developmentally delayed. Four children in two families appear to have a benign variant of methylmalonic acidemia. Based on these studies the observed incidence of methylmalonic acidemia in Massachusetts is 1:48,000. Screening for methylmalonic aciduria may be an appropriate addition to newborn screening programs.

Child↗
PubMed1981

A study of cardiovascular risk in heterozygotes for homocystinuria.

Early atherosclerotic-like lesions and thromboemobolic problems are prominent in homocystinuric patients. Recent evidence suggested that mild homocyst(e)inemia, such as is present in heterozygotes for homocystinuria due to cystathionine synthase deficiency, may cause a marked excess in early ischemic heart disease. To evaluate the risk due to mild homocyst(e)inemia, the frequencies of heart attacks and strokes in parents and grandparents of homocystinuric children were assessed in the present study. No statistically significant increases in the incidence of heart attacks or strokes were consistently detected. The data available are sufficient to virtually exclude an increase in the cardiovascular risk for homocystinuria heterozygotes of as much as fivefold compared to controls, and to make very improbable a relative risk of as much as threefold. Less than 5% of homocystinuria heterozygotes are likely to have a fatal or nonfatal heart attack by age 50. These results fail to suggest that mild homecyst(e)inemia is an important contributory factor in the overall incidence of cardiovascular disease.

Adult↗
PubMed1980

Maternal phenylketonuria and hyperphenylalaninemia. An international survey of the outcome of untreated and treated pregnancies.

Since many women with phenylketonuria (PKU) will have children of their own, we were interested in ascertaining the effect of maternal PKU and hyperphenylalaninemia on the offspring of such women. We reviewed the literature on this subject and obtained additional unpublished data through an international survey. Data were collected on 524 pregnancies in 155 women; in 34 pregnancies a low-phenylalanine diet was begun after or shortly before pregnancy was established. Among untreated pregnancies, the frequencies of mental retardation, microcephaly, and congenital heart disease were greatly increased over those in the normal population, and these increases correlated with the mother's blood levels of phenylalanine. Ninety-five per cent of mothers with blood phenylalanine concentrations of 20 mg per deciliter or higher had at least one mentally retarded child. Bias introduced by case-finding methods cannot explain these results. It is not clear from our review whether dietary treatment begun after conception is helpful, but treatment begun before conception should be evaluated.

Abortion, Spontaneous↗
PubMed1980

Diet termination in children with phenylketonuria: a review of psychological assessments used to determine outcome.

This paper reviews the 19 published studies that have utilized psychological assessments in determining the outcome of children with phenylketonuria who have discontinued a phenylalanine-restricted diet. About half the studies showed that, after diet termination, the intellectual performance of children decreased, while the other studies indicated that the intellectual performance of the children did not change. Difficulties in the use of intelligence tests to answer questions about diet termination are outlined. Due to the methodological difficulties and the varying results reported, the issue concerning the safety of diet discontinuation remains unresolved. The conclusion is that the task now is to differentiate those children who should remain on the diet from those who may safely terminate.

Child, Preschool↗
PubMed1980

Cord-blood tyrosine levels in the full-term phenylketonuric fetus and the "justification hypothesis".

The "justification hypothesis" attributes mental retardation in phenylketonuria (PKU) to an inability of the heterozygous mother to deliver an appropriate amount of tyrosine to the PKU fetus who, in turn, is unable to correct for this deficiency because of its genetic constitution. We tested this hypothesis by measuring concentrations of tyrosine and phenylalanine in cord blood obtained at delivery from nine infants with PKU and five infants with persistent (non-PKU) hyperphenylalaninemia (PHP). For each of these specimens there were four control cord-blood specimens from infants born on the same day and, generally, in the same hospital. PKU and PHP groups were similar with respect to cord-blood tyrosine and phenylalanine values. There was no biologically significant deficiency of tyrosine in cord blood of the pooled PKU and PHP deficiency of tyrosine in cord blood of the pooled PKU and PHP groups (54 +/- 10 microM, mean +/- SD) compared with controls (61 +/- 16 microM, P = 0.13). On the other hand, phenylalanine in cord blood of the pooled PKU and PHP groups was significantly increased (144 +/- 30 microM, mean +/- SD) compared with controls (128 +/- 24, P = 0.004). The mangitude of the differences in cord-blood tyrosine and phenylalanine between control and PKU subjects are so small that it is unlikely that they have any consequences for physical and mental development. The justification hypothesis, as it pertains to blood tyrosine at term, is not upheld.

Female↗
PubMed1978

Screening for congenital hypothyroidism. Results in the newborn population of New England.

During the first year of operation, the New England Regional Hypothyroidism Screening Program determined the concentration of thyroxine (T4) levels in dried blood on filter paper from 129,028 infants born in Connecticut, Maine, Massachusetts, New Hampshire, and Rhode Island. Specimens from approximately 3,800 neonates were found to have levels of T4 below the lower limit of normal (less than 6.0 microgram/dl) and were assayed for thyroid-stimulating hormone (TSH) content. Levels of TSH were elevated (greater than 20 muU/ml) in 31 infants, 23 of whom eventually proved to have unequivocal hypothyroidism. Based on these figures and including two hypothyroid infants who were not tested, the incidence of congenital hypothyroidism in the New England region is approximately 1:5,200 births. The estimation of T4 values supplemented by measurement of TSH values on specimens with low T4 values has proved to be a satisfactory approach to large-scale screening for congenital hypothyroidism.

Congenital Hypothyroidism↗
PubMed1978

Galactose-1-phosphate uridyl transferase deficiency due to Duarte/galactosemia combined variation: clinical and biochemical studies.

The most common abnormality detected by the screening of newborn infants for galactosemia is a deficiency of galactose-1-phosphate uridyl transferase due to the presence in one individual of allelic genes for the Duarte variant and for galactosemia. Clinical studies of ten untreated individuals with this genetic compound, including three adults, failed to reveal evidence of cataracts, liver disease, or mental subnormality, the major clinical complications associated with galactosemia. Galactose-1-phosphate was not detectable in umbilical cord blood from one infant. Galactose was not detectable in random blood specimens from any of the individuals and was present in only small amounts following ingestion of milk in one infant and a child. It would appear that this common gentic variation is usually, if not always, benign.

Adult↗
PubMed1978

Vitamin B6-dependent seizures: pathology and chemical findings in brain.

A 13 1/2-year-old child died with vitamin B6-dependent seizures in progress. Microscopic findings in brain included an abnormally sparse quantity of central myelinated fibers in the cerebral hemispheres. Glutamic acid concentrations were elevated and GABA concentrations reduced in the frontal and occipital cortices but not in the spinal cord. All other amino acid concentrations were normal, except for increased cystathionine in the occipital cortex. Pyridoxal-5-phosphate (PLP) was reduced in the frontal cortex. Glutamic acid decarboxylase activity comparable to that of controls was detected when the PLP concentration was greater than 0.05 mM. These findings suggest that pyridoxine-dependent seizures in man are associated with reduced GABA concentrations in the brain and with diminished central white matter structures.

Adolescent↗
PubMed1977

Starch gel electrophoresis for galactose-1-phosphate uridylyl-transferase applied to dried filter paper blood specimens.

Starch gel electrophoresis of galactose-1-phosphate uridylyl transferase has been adapted for use on dried filter paper blood specimens submitted for the purposes of routine newborn screening for galactosemia and other inborn errors of metabolism. Selected for study were those specimens with reduced transferase activity, as determined by the Beutler enzyme spot screening test. Clinically benign low activity enzyme variants were readily identified, thus reducing significantly the number of requested additional blood specimens. Transferase-deficient specimens with potential clinical significance had too little activity for transferase visualization and thus could be separated from the benign variants. This technique would facilitate routine newborn screening for galactosemia.

Carrier State↗
PubMed1976

Pericardial fluid analysis in scleroderma (systemic sclerosis).

A patient with scleroderma who presented with pericarditis and effusion is described. Aspirates from this pericardial effusion had the characteristics of an exudate with no evidence of autoantibodies, immune complexes or complement depletion. These findings suggest that the mechanisms operating in the production of pericardial effusion in scleroderma may be different from those found in rheumatoid arthritis and systemic lupus erythematosus.

Aged↗