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Biomedical subjects

R H Glew

Publications and source records attributed to R H Glew.

At least 199 records · Page 11Linked to original sources

Acid phosphatase in Gaucher's disease.

Increased acid phosphatase activity in the serum and tissues of patients with Gaucher's disease has now been recognized for two decades, but as yet no relation has been established between the enzyme and the etiology and progress of the disease. Here, we review results obtained by various investigators, ranging from a consideration of the methods used for the evaluation of serum acid phosphatase in Gaucher's disease to the most recent findings regarding the purification and characterization of two acid phosphatase isoenzymes from the spleen from patients with Gaucher's disease. We also discuss the intracellular location of tissue acid phosphatase in patients with Gaucher's disease and its contribution to the increased activity in serum.

Acid Phosphatase↗

Comparison of rates of hydrolysis of N-oleoyl and N-stearoyl glucocerebroside in patients with Gaucher's disease.

The deficiency of oleic acid as one of the fatty acids in glucocerebrosides that accumulate (31--77 mg/g dry weight) in the spleen in patients with Gaucher's disease was confirmed in 9 cases. In an effort to account for the 10-fold difference between the oleoyl glycocerebroside content of glucocerebrosides in spleen from controls and patients with Gaucher's disease, we compared the ability of extracts of spleen and fibroblasts from individuals with various forms of Gaucher's disease and controls to hydrolyze [14C]stearoyl and [3H]oleoyl glucocerebroside. The residual glucosylceramidase activity in patients with Gaucher's disease hydrolyzes the glucose moiety of oleoyl glucocerebroside at approximately the same rate as that of stearoyl glucocerebroside. Similarly, the more active glucosylceramidase of control tissue acts upon both oleoyl and stearoyl glucocerebrosides with equal efficiency. These observations indicate that a mutation affecting the substrate specificity of glucosylceramidase cannot account for the lack of oleic acid-containing glucocerebrosides in patients with Gaucher's disease. Thus, the hypothesis that the difference in fatty acid composition found in glucocerebroside is obtained as a result of a mutation affecting the specificity of the residual glucosylceramidase must be rejected.

Adult↗

Changes in serum lysosomal hydrolases in marasmus.

The activities of several lysosomal hydrolases including beta-glucuronidase, acid phosphatase and hexosaminidase were compared in serum from 19 well-nourished subjects and 13 children (age 5--24 months) who were suffering from marasmus. The marasmic children exhibited growth retardation and muscle wastage but had normal serum protein values and absence of psychomotor retardation or oedema. Significant changes were observed in serum beta-glucuronidase and acid phosphatase activities. Compared to the control group, serum beta-glucuronidase (determined at pH 4.5 using the fluorogenic substrate, 4-methylumbelliferyl-beta-D-glucuronide) was 2.3-fold higher (p less than 0.001) in the marasmic children. In contrast, serum acid phosphatase values were approximately 50% lower (p less than 0.01) in the marasmic population. Serum hexosaminidase values in the two groups under study were not significantly different. Determination of the beta-glucuronidase to acid phosphatase ratio permitted effective discrimination (p less than 0.001) of serum from normal and protein-calorie malnourished children. The finding that the elevated value of the beta-glucuronidase : acid phosphatase ratio (0.64--1.37) decreased to within the normal range of values (0.10--0.43) after nutritional rehabilitation of several marasmic cases indicates that the determination of serum lysosomal hydrolases using fluorogenic substrates might provide a rapid and sensitive quantitative method for objectively evaluating the status of protein-calorie malnourished children and their responsiveness to nutritional therapy.

Acid Phosphatase↗

Familial psychosis and diverse neurologic abnormalities in adult-onset Gaucher's disease.

A family is described in which adult-onset Gaucher's disease developed, followed years later by atypical psychotic disorders with neurologic and electroencephalographic abnormalities. A biochemical investigation of primary and secondary enzyme alterations in the index case was performed in an attempt to identify a pattern that might be specific to this clinical profile. The literature pertaining to CNS involvement in adult patients with Gaucher's disease is also reviewed. An etiologic link may exist between the inherited metabolic disorder and associated neuropsychiatric impairment. The biochemical basis of this hypothesized association remains unclear, however, and further enzymatic and pathologic investigations are warranted.

Acid Phosphatase↗

Demonstration of multiple forms of acid phosphatase in hemolymph of the African snail, Archachatina marginata.

1. Hemolymph from the giant African snail Archachatina marginata has been analyzed for its content of certain lysosomal hydrolases and shown to contain substantial quantities of acid phosphatase (285 units/ml) hexosaminidase (512 units per ml) and beta-glucuronidase (28 units/ml). 2. Hemolymph acid phosphatase can be fractionated into 6 active components by DEAE-Sephadex chromatography. 3. Some of the acid phosphatase species can be distinguished on the basis of heat stability, pH dependency and sensitivity to inhibitors including phosphate, L(+) tartrate, fluoride, formaldehyde and 1.10 phenanthroline.

Acid Phosphatase↗

Protection of sodium dodecyl sulfate-induced aggregation of concanalvalin A by saccharide ligands.

Concanavalin A is visibly aggregated by low concentrations of sodium dodecyl sulfate, maximum aggregation being obtained at pH 4.6. Other denaturants, such as urea, guanidine hydrochloride, Triton X-100, cetyltrimethylammonium bromide, Tween 80, and Brij 35 are ineffective in promoting visible aggregation. The sodium dodecyl sulfate-induced aggregation of concanavalin A requires the presence of an intact, saccharide-ligand binding-site. Rapid and complete reversal of the detergent effect was achieved by use of saccharides which bind to the lectin. Such compounds as tryptophan and o-nitrophenyl beta-D-galactopyranoside did not inhibit the aggregation of concanavalin A by sodium dodecyl sulfate, suggesting that the detergent does not bind the hydrophobic pocket on the surface of the protein. The results suggest that concanavalin A may have an additional, ligand-binding site which is metal-dependent and which can be modified by the addition of a saccharide ligand.

Chemical Phenomena↗

Effect of protein binding on the activity of penicillins in combination with gentamicin against enterococci.

To assess the effect of protein binding by human serum on the synergistic interaction of penicillins with gentamicin, time-kill curves were determined for four penicillins alone and in combination with gentamicin against 10 blood isolates of enterococci. Killing curves demonstrated synergism with penicillin G plus gentamicin against all 10 strains in either broth or 50% human serum. In broth the combinations of nafcillin plus gentamicin and oxacillin plus gentamicin were synergistic against 10 of 10 strains and 4 of 10 strains, respectively. However, in serum, nafcillin plus gentamicin was synergistically bactericidal against only two strains and oxacillin plus gentamicin against none. Methicillin plus gentamicin was synergistic against none of the enterococci in either medium. Thus, the semisynthetic, penicillinase-resistant penicillins are unlikely to be effective in the therapy of patients with enterococcal endocarditis.

Blood Bactericidal Activity↗

Comparison of the carbohydrate and amino acid composition of normal and S-variant alpha-1-antitrypsin.

alpha-1-Antitrypsin has been isolated and purified from the serum of an individual with the Pi S phenotype whose serum contains only 50--60% as much alpha-1-antitrypsin as normal M-type serum. The preparation was homogeneous by the criteria of sodium dodecyl sulfate polyacrylamide gel electrophoresis and sedimentation equilibrium ultracentrigufation. When analyzed in the ultracentrifuge, the S-type alpha-1-antitrypsin exhibited a molecular weight of 47,500 which was essentially the same as that of the M-type (47,300) and the Z-type (47,500) alpha-1-antitrypsin. The S-type alpha-1-antitrypsin contains 15.2% carbohydrate consisting of 16.4 residues/mol of N-acetylglucosamine, 7.8 residues/mol of mannose. 6.7 residues/mol of galactose and 7.1 residues/mol of sialic acid which is essentially the same as the carbohydrate composition of the M-type alpha-1-antitrypsin. In addition, M- and S-type alpha-1-antitrypsin have very similar amino acid compositions.

Amino Acids↗