Sally Kelly

Fluorimetric assay of acid lipase in human leukocytes

A fluorimetric assay for leukocyte acid lipase, the enzyme defect in Wolman disease, is described. The method requires a smaller volume of blood and can be performed more rapidly than the present colorimetric assay for the leukocyte enzyme.

A hypothesis on the homocystinuric's responce to pyridoxine

Abstract Quantitative amino acid assays of urine samples from a homocystinuric receiving pyridoxine revealed a biochemical response involving cystine formation and metabolism through homolanthionine. The pyridoxine supply is proposed as a determinant of the route choice.

A fluorescent spot test for the detection of galactokinase deficiency

Abstract A fluorescent spot test specific for galactokinase and suitable for screening is described. The test utilizes dried blood spots and a visual end point.

A microfluorometric assay of leukocyte α-1,4-glucosidase

Abstract We describe an improved method for detecting deficiency of the acid hydrolase, α-l,4-glucosidase in leukocytes, the enzyme defect in glycogen storage disease Type II (Pompe disease). The procedure requires smaller volumes of blood and less time than previous methods. The assay involves the separation of leukocytes by Peters method for β-glucosidase and a modification of Salafsky and Nadlers fluorometric method for α-glucosidase.

Screening for galactosemia in New York State.

CONVENIENT blood tests for galactosemia (1-5) now permit wide-scale screening and early identification of babies affected, hopefully before irreparable damage or death ensues. In conjunction with New York States mandatory screening program for phenylketonuria (PKU) a,t birth (6), we tested a large population of newborns for galactosemia with a fluorescent spot method (5) and found the procedure a practical means of identifying babies in whom galactosemia is likely to develop.

A fluorescent spot test for creatine kinase

Abstract A fluorescent spot test for creatine kinase in serum is described. Sensitivity varied with DPNH concentration, incubation period, size, and type of sample. Under optimum conditions samples with varying degrees of excess enzyme were distinguished from those with normal activity (

Glutathione peroxidase in dried blood spots

A new procedure utilizing dried blood spots was developed for detecting glutathione peroxidase deficiency. Samples from a known patient with a partial defect and from rats with an induced deficiency were distinguished from respective control groups by their longer defluorescence endpoints., Samples from 100 patients with anemia and 2 phenylketonuric infants on low-protein diets contained glutathione peroxidase activity similar to that in 82 controls, when screened for the enzyme defect by the new procedure.

Phenotypes of Galactosaemia in Infants Screened at Birth

Five genetic forms of galactosaemia were found in 15 infants identified in a newborn screening programme through a combination of laboratory criteria, involving serial assays of transferase and interpretation of isozyme patterns. The biochemical phenotypes of some infants were ascertained only weeks after birth, when transferase activities had increased from initial levels.

A microfluorometric assay of the lysosomal arylsulfatases in leukocytes

Abstract Techniques for measuring the lysosomal arylsulfatases A and B, the hydrolases deficient in metachromatic leukodystrophy and Maroteaux-Lamy disease, respectively, are, for the most part, in the developmental stages. Existing methods for assay of leukocyte enzyme, for example, utilize large (10 ml) volumes of blood [1–6], a requirement which discourages their application in tests of infants and young children. Some, furthermore, do not distinguish between the activities of arylsulfatase A and B [6] and thus are of limited value in providing data for the diagnosis of the respective storage disease. All employ a time-consuming process for the purification of leukocytes. The assays for leukocyte enzyme, described below, are rapid, pertain to the individual lysosomal arylsulfatases, employ methylumbelliferyl substrate and require only small volumes of blood.

Galactose-Metabolizing Enzymes in the Rat

The induction of galactose-type cataracts in rats with a yogurt diet (1) resembles the natural cataractogenic action of the milk sugars in patients with galactosemia, a hereditary disease characterized by galactose-1-phosphate uridyl transferase deficiency. The role of the transferase and other galactose-metabolizing enzymes in the pathogenesis of cataracts in rats has not been assessed, however, although enzymes in the glycolytic (2-4) and oxidative shunt pathways (5, 6) are inhibited when rats are fed strict galactose diets. Indeed, the decreasing activities of the liver enzymes, galactokinase (7), transferase (8, 9), and uridine diphosphogalactose-4-epimerase (10) in the aging rat suggest that one or all of the enzymes of the sugar nucleotide pathway limit carbohydrate metabolism in rats fed on galactose. There appears to be a similar age-dependence in the respective red cell enzymes. Materials and Methods. Male Wistar rats were bled from the heart at 1, 2, 3, 8, and 16 weeks of age in groups of three or more. Galactose-1-phosphate uridyl transferase was assayed in the red cells by a fluorometric method (11, 12) and galactokinase, by an isotopic method (13). Red cells from five healthy men and women, ranging in ages from 21 to 50 years, served as controls for the conditions of the assays, which had been selected for enzymes from human tissues. The production of reduced triphosphopyridine nucleotide (TPNH) at constant rates (Fig. 1) by the transferases from the two species assured us, for example, that the substrate conditions during the 30 min incubation period were adequate for the rat transferase. Nor was differential absorbance of rat hemoglobin a source of error in calculating transferase activities, as the hemoglobins of both species approached their maxima at 410 nm.