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Biomedical subjects

L J Elsas

Publications and source records attributed to L J Elsas.

At least 127 records · Page 7Linked to original sources
PubMed1978

Inherited human collagen lysyl hydroxylase deficiency: ascorbic acid response.

A patient is described with congenital hypotonia, lax joints, friable skin, hemorrhagic scars, high-arched palate, and borderline microcornea. Acid hydrolyzed whole skin collagen had a reduced hydroxylysine content of 0.5 residues per 1,000 as compared to 5.1 +/- 0.7 in control skin. Collagen lysyl hydroxylase in dialyzed subcellular fractions of cultured skin fibroblasts required L-ascorbate as a principal cofactor. Activity of this enzyme in cultured skin fibroblasts derived from this patient, his father, and mother were 17%, 66%, and 39% of control values, respectively. Collagen prolyl hydroxylase activity was normal. Pharmacologic amounts of oral vitamin C (4 gm/day) produced an increase and withdrawal resulted in abrupt diminution of urinary excretion of hydroxylysine. Over a two-year period the patient's wound healing and muscle strength improved and corneal diameter increased. Hydroxylysine content of the skin did not increase.

Ascorbic Acid↗
PubMed1978

Phenylketonuria heterozygote detection in families with affected children.

Improved approaches to the problem of heterozygote detection for phenylketonuria (PKU) were developed in this study. The discrimination was based on 85 obligate heterozygotes and 45 controls who were neither pregnant nor on birth control medication. The best separation between hetrozygotes and normals was achieved with a linear discriminant function involving the logarithms of the serum concentrations of phenylalanine, tyrosine, and tryptophan. The theoretical overlap area between the distributions of heterozygotes and controls based on the above function, was 3.75%. In the 19 obligate hetrozygotes and 13 controls who were either pregnant or on birth control medication, the best separation was achieved with a linear discriminant function involving the logarithms of the serum concentrations of phenylalanine and tyrosine. The theoretical overlap area was 8.23%. The genetic accuracy of the discriminant function was confirmed by testing the results with parental-child exclusions, segregation analysis, and the frequency of heterozygosity in nonrelated collateral spouses. Finally, there was evidence suggesting that the antihypertensive agent, aldomet, alters serum tyrosine and tryptophan levels.

Ethnicity↗
PubMed1977

Testing for the Tay-Sachs gene in the Atlanta Jewish population.

In May 1975, three mass screening clinics for the asymptomatic Tay-Sachs carrier were held in Atlanta, Georgia. Ninety percent of the 2,330 adults screened were of Ashkenazi Jewish ancestry. One hundred seventy-six people were identified as possible carriers, 145 returned for retesting, and 74 were diagnosed as carriers. The Tay-Sachs heterozygote frequency estimated from this tested population was 0.043 or 1 in 23. Retesting of all possible carriers and assessment of their first-degree relatives were emphasized as saids in diagnosis of the carrier state. Our results indicated that the hexosaminidase A values in the white celll lysates used for the retest procedure provided a more reliable diagnosis of the carrier state than did enzyme values obtained from screening sera alone. Test results from first-degree relatives in all cases supported the assigned genotype of probands.

Europe↗
PubMed1975

Amino acid transport by aggregates of cultured chicken heart cells. Effect of insulin.

Single heart cells dissociated from 14-day-old chicken embryos were reagregated into spheroidal clusters on a gyratory shaker and centrifuged to form cohesive discs of approximately 400 aggregates. These cultured cells accumulated 2-amino[1-14C]isobutyric acid against a gradient. When incubated for 3 hours in a protein-free, buffered, balanced salt solution, concentrative transport decreased to a stable basal level. Incubation in the presence of sodium bovine insulin prevented this fall in transport activity and resulted in increased 2-aminoisobutyric acid uptake to concentrations 40 time sthat in the medium during a subsequent 3-hour transport assay. Intracellular accumulation of 2-aminoisobutyric acid was linear during the initial 15 min of transport in the presence and absence of added insulin. Basal transport of 2-aminoisobutyric acid was temperature-dependent, requied extracellular sodium greater than 125 meg/liter, and demonstrated saturation with an apparent Vmax of 3.4 mmol/liter/10 min and an apparent Km of 2.6 mM. Basal transport activity was not reduced by cycloheximide or puromycin even after 3 hours of exposure...

Aminoisobutyric Acids↗
PubMed1975

Classic phenylketonuria: diagnosis through heterozygote detection.

Fifty-nine male and female (pregnant and nonpregnant) normal control subjects were differentiated from 18 male and female obligate heterozygotes for classic PKU. The method of genotyping utilized midday semifasting blood P and T quantitated by ion-exchange chromatography, an empiric determinant, P-2/T, and a discriminant function (sigma), in which sigma = a(1)(P)+a(2)(T);a(1) and a(2) were computed by multivariate analysis, This method of genotyping was applied in three clinical settings. In one family hyperphenylalaninemia was differentiated from classic PKU in two sisters with elevated blood P. In a second family maternal PKU was related to microcephaly in two retarded siblings, one of whom was also homozygous for classic PKU. In a third family a diagnosis of classic PKU was established in a normal-appearing infant whose blood P concentration was elevated.

Adolescent↗