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Biomedical subjects

E Beutler

Publications and source records attributed to E Beutler.

At least 397 records · Page 22Linked to original sources

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↗

Existence of only a single functional pool of adenosine triphosphate in human erythrocytes.

The question of whether separate "membrane" and "soluble" pools of ATP exist in erythrocytes has been examined. Phosphoglycerate kinase (EC 2.7.2.3)-derived ("membrane") ATP was labeled by short-term incubation with inorganic [32P]phosphate. Pyruvate kinase (EC 2.7.1.40)-derived ("soluble")ATP is not labeled under these circumstances. The specific activity of the gamma-phosphate of "soluble" ATP was then evaluated by the addition of 2-deoxyglucose and measurement of the specific activity of 2-deoxyglucose-6-[32P]phosphate formed. This specific activity was essentially the same as the overall specific activity of erythrocyte ATP gama-phosphate, indicating that no functional pools of phosphoglycerate kinase-derived and pyruvate kinase-derived ATP exist in erythrocytes.

Adenosine Triphosphate↗

Effect of anti-spectrin antibody and ATP on deformability of resealed erythrocyte membranes.

Deformability of resealed erythrocyte membranes was measured by using an ektacytometer. Divalent anti-spectrin antibody, but not monovalent anti-spectrin Fab fragments, decreased membrane deformability. Membranes resealed with MgATP were more deformable than those without MgATP. Exogenous alkaline phosphatase, which dephosphorylates spectrin, decreased membrane deformability. These results suggest that spectrin is an essential component of the system that determines erythrocyte deformability. They are consistent with the view that the role of ATP in membrane deformability is mediated through phosphorylation of the spectrin.

Adenosine Triphosphate↗

An assay for terminal deoxynucleotidyl transferase in leukocytes and bone marrow.

A modified technic for the assay of terminal transferase activity in leukocytes and bone marrow is presented. 3H-deoxyadenosine-5' -triphosphate serves as nucleotide donor and (dA)10 as primer. The reaction product is collected as a trichloroacetic acid precipitate, which is dissolved for radioactive quantitation. All reagents are commercially available, and the procedure has been designed to minimize cost and to provide low blank values. Excellent linearity between enzymatic concentration and activity and between time and activity is observed. Because the assay is carried out at conditions approaching the optimum for the enzyme, the measured activities are more than ten times those observed with previous methods.

Bone Marrow↗

Acid hydrolases in normal B and T blood lymphocytes.

B and T lymphocytes were separated by means of the spontaneous sheep red blood cell rosette formation technique from 3 normal donors. The following acid hydrolases were biochemically determined on separated B and T lymphocytes: acid phosphatase, beta-glucuronidase, beta-galactosidase, beta-hexosaminidase, alpha-arabinosidase, alpha-galactosidase, alpha-mannosidase, alpha-glucosidase, and pH 4.0 and pH 5.0 beta-glucosidase. The activities of most of the acid hydrolases including acid phosphatase and beta-glucuronidase were found to be slightly decreased in B lymphocytes when compared to T lymphocytes. However, alpha-mannosidase activity was found to be significantly higher in the B lymphocytes than in the T lymphocytes and offers the possibility of using this enzyme as a B lymphocyte marker.

B-Lymphocytes↗

Hereditary nonspherocytic hemolytic anemia and hexokinase deficiency.

An 11-yr-old child with mild chronic hemolytic anemia was found to have decreased red cell hexokinase activity in spite of the reduced mean age of her red cell population. Similar decreases in red cell hexokinase activity were documented in the patient's parents and in one sib. The red cells were morphologically normal. Red cell 2,3-DPG levels were normal and ATP and glucose-6-phosphate levels were diminished. The kinetic properties, electrophoretic mobility, and thermal stability of the residual red cell hexokinase were normal or nearly so. Glucose consumption of the hexokinase-deficient cells was not appreciably decreased, probably because less of the potent inhibitor glucose-6-phosphate was present in the erythrocytes. It is likely, although not certain, that in this patient nonspherocytic hemolytic anemia resulted from hexokinase deficiency.

Adenosine Triphosphate↗

Starch gel electrophoresis of erythrocyte hypoxanthine-guanine phosphoribosyl transferase and adenine phosphoribosyl transferase: a population survey.

Vertical starch gel electrophoresis of hypoxanthine-guanine phosphoribosyl transferase (HGPRT) and adenine phosphoribosyl transferase (APRT) was performed in several population groups including Caucasians, Negroes and Orientals. The red cells of a total of 244 individuals were examined for HGPRT and those of 265 for APRT and no variants were detected.

Adenine Phosphoribosyltransferase↗

alpha-galactosidase A from human placenta. Stability and subunit size.

alpha-Galactosidase A (alpha-D-galactoside galactohydrolase, EC 3.2.1.22) was purified from human placenta. The purified enzyme showed one major band on polyacrylamide gel electrophoresis and a single precipitin line on double immunodiffusion. Electrophoresis of the purified, S-carboxymethylated enzyme on sodium dodecyl sulfate polyacrylamide gel showed one component with a molecular weight of about 65 000, but electrophoresis of the non-S-carboxymethylated enzyme showed two components, a major band with a molecular weight of 67 500 and a diffuse band with a molecular weight of 47 000. We suggest that the smaller diffuse component is a degradation product and that the enzyme is a dimer with a molecular weight of approximately 150 000 and a subunit of molecular weight of about 67 500. Antibody raised against the purified enzyme quantitatively precipitated alpha-galactosidase A, but not alpha-galactosidase in Fabry's disease fibroblasts. The alpha-galactosidase A is very heat labile and pH sensitive. It is most stable in concentrated solution at low temperature and at a pH of 5.0 to 6.0. When added to plasma at 37 degrees C, it has a half-life of only 17 min. This imposes a serious obstacle to its use in the treatment of Fabry's disease.

Electrophoresis, Disc↗

Variants of galactose-1-phosphate uridyl transferase in the Greek populations.

The frequency of variants of galactose-1-phosphate uridyl transferase was determined among the nine Greek populations by studying a sample of 1570 unselected individuals. Average frequency of normal allele GALT=0.942, galactosemia gen GALTG=0.0021 and the Duarte variant gene GALTD=0.0548 were observed. Frequency of galactosemia heterozygotes among Greeks was similar to that in other Caucasian populations, but the frequency of the Duarte variant was considerably higher. With the exception of two populations, one with low (Epirus) and one with high (Thrace) frequencies, the polymorphism of the Duarte variant displays very similar frequencies in the various Greek population groups.

Adult↗