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Biomedical subjects

R H Glew

Publications and source records attributed to R H Glew.

At least 163 records · Page 9Linked to original sources
PubMed1984

Activators of spleen glucocerebrosidase from controls and patients with various forms of Gaucher's disease.

Glucocerebrosidase from normal human spleen, and spleen from cases of neurologic (types 2 and 3) and nonneurologic (type 1) Gaucher's disease, was delipidated and inactivated by extraction from membranes with sodium cholate and ice-cold 1-butanol. Control glucocerebrosidase was stimulated markedly by large quantities (20-30 micrograms/assay) of phosphatidylserine (PS), or by a combination of smaller amounts (1-2 micrograms) of PS and 3 micrograms of a heat-stable factor (HSF) derived from the spleen of a patient with Gaucher's disease. The residual glucocerebrosidase from a nonneurologic case, but not a neurologic case, was also responsive to PS and HSF. The combination of HSF and PS decreased the Km of the normal enzyme for 4-methylumbelliferyl-beta-D-glucopyranoside from 8.0 to 1.6 mM. These effectors also increased the reactivity of glucocerebrosidase to the inhibitor conduritol B epoxide; HSF alone had no effect (t1/2 = 19 +/- 0.5 min) whereas the maximum rate of inactivation (t1/2 = 4.0 min) by conduritol B epoxide was achieved in the presence of a mixture of PS (1 microgram) and HSF (3 micrograms). Phosphatidylglycerol (PG) and phosphatidic acid, also acidic phospholipids, were effective activators of glucocerebrosidase. Varying the fatty acid composition of PG had little effect on its ability to stimulate glucocerebrosidase activity. However, in the case of phosphatidylcholine (PC), a weaker activator than PG or PS, fatty acid composition had a significant impact on the ability of this neutral lipid to activate glucocerebrosidase; dilinoleoyl-PC and dicaproyl-PC were moderately effective activators, but distearoyl-PC and dioleoyl-PC were almost totally inactive. The mono-, and di-, and trisialogangliosides (GM1, GD1, and GT1 were less than half as effective as PS as activators of glucocerebrosidase. These results indicate that acidic phospholipids and the heat-stable factor may both play a role in explaining the genetic heterogeneity of Gaucher's disease.

Enzyme Activation↗
PubMed1984

Delayed appearance of vancomycin-induced neutropenia in a patient with chronic renal failure.

A patient receiving hemodialysis for chronic renal failure had neutropenia six weeks after administration of his last dose of intravenous vancomycin and in the absence of other drug therapy. This case provides confirmation that neutropenia can be seen with vancomycin therapy; suggests an immunologic basis for the reaction, since the patient exhibited a concomitant hypersensitivity rash; and points out that delayed clearance of vancomycin in patients with chronic renal failure can produce late onset of side effects in such patients.

Agranulocytosis↗
PubMed1984

Early synergistic interactions between amikacin and six beta-lactam antibiotics against multiply resistant members of the family Enterobacteriaceae.

An in vitro comparison of the early synergistic interaction between amikacin and each of six beta-lactam antibiotics was made by using time-kill curves against 48 multiply resistant members of the family Enterobacteriaceae. Overall, these six combinations demonstrated early synergism (greater than or equal to 2 logs of increased kill after 7 h of incubation) against the 48 strains on 74% (range, 67 to 85%) of occasions; cefotaxime-amikacin and piperacillin-amikacin were the most efficacious combinations. Antagonism was not observed with any of the combinations against any of the 48 Enterobacteriaceae strains tested.

Amikacin↗
PubMed1984

Serum alpha-mannosidase in patients with alcoholic liver disease.

Sera from 9 persons with either biopsy-proven alcoholic liver disease or a history of chronic, excessive ethanol consumption were analyzed for their content of various hydrolases. Compared to controls, significant elevations in the following enzyme activities were seen in sera from the patient population: acid phosphatase (2.0-fold), beta-glucuronidase (2.1-fold), hexosaminidase (1.4-fold), and alpha-L-fucosidase (2.3-fold). In addition, alpha-mannosidase activity, previously reported to be unchanged in cases of hepatic cirrhosis [Reglero et al., Clinica chim. Acta 130: 155-158], (1980) was found to be significantly increased (p less than 0.001) when assays were performed at acid (pH 4.5) or intermediate (pH 5.5) hydrogen ion concentrations. Fractionation of sera on DEAE-Sephadex columns showed that the increase in alpha-mannosidase activity in the serum of patients with alcoholic liver disease was due to increases in the level of at least one 'acid alpha-mannosidase' and two intermediate pH optimum alpha-mannosidases. The general increase in the activity of a group of glycosidases is consistent with a hypothesis involving decreased clearance of glycoproteins from the blood of persons with hepatic cirrhosis.

Acid Phosphatase↗
PubMed1983

Parotitis associated with Eikenella corrodens in a healthy adult.

Eikenella corrodens is a gram-negative, facultatively anaerobic rod that is part of the normal oral flora. Although its pathogenicity was uncertain until recently, E corrodens has been implicated in a variety of human infections, usually in mixed culture, and commonly in patients predisposed by virtue of trauma, malignant neoplasms, antecedent surgery, or parenteral drug abuse. Parotitis due to E corrodens occurred in a healthy 72-year-old woman. Therapy with high-dose intravenous oxacillin sodium had been without effect, but surgical drainage plus antibiotic therapy directed against E corrodens produced prompt resolution.

Aged↗
PubMed1983

Early synergistic interaction between semisynthetic penicillins and aminoglycosidic aminocyclitols against Enterobacteriaceae.

Time-kill curves were used to assess the relative in vitro efficacy of the early interaction of three semisynthetic penicillins with two aminoglycosides against 48 Enterobacteriaceae strains. The most efficacious combinations were piperacillin plus amikacin, which demonstrated synergism (greater than or equal to 2 logs of increased kill after 7 h of incubation) against 43 of 48 (90%) strains, and piperacillin plus gentamicin, which exhibited synergism against 25 of 48 (52%) strains. With the combinations of carbenicillin or ticarcillin plus amikacin or gentamicin, early synergistic killing was demonstrated against only 12 to 29% of the strains.

Amikacin↗
PubMed1983

Stability of gentamicin, tobramycin, and amikacin in combination with four beta-lactam antibiotics.

The stability of the aminoglycosides gentamicin, tobramycin, and amikacin stored in combination with carbenicillin, piperacillin, cefotaxime, and moxalactam was evaluated at four temperatures (25, 4, -8, and -70 degrees C) over a 3-week period. Amikacin was the most stable of the aminoglycosides and demonstrated no loss of activity when stored with either carbenicillin or piperacillin. Gentamicin and tobramycin were inactivated by carbenicillin and piperacillin at 25 and 4 degrees C, with aminoglycoside activity declining substantially after 8 to 48 h of storage; virtually no loss of gentamicin or tobramycin activity occurred with storage at -8 or -70 degrees C. Cefotaxime and moxalactam produced no degradation of any of the three aminoglycosides.

Amikacin↗
PubMed1982

Brain glucocerebrosidase in Gaucher's disease.

Using glucocerebroside labeled with carbon 14 as the substrate, we determined that homogenates of brain tissue from both neuropathic and nonneuropathic cases of Gaucher's disease were profoundly deficient (more than 85%) in glucocerebrosidase activity. The beta-glucosidase activity, as measured with 4-methylumbelliferyl-beta-D-glucopyranoside as the substrate, in the homogenates of brain from four cases of Gaucher's disease was less sensitive to inhibition by conduritol B epoxide (CBE) when compared with normal brain beta-glucosidase. However, when homogenates were assayed with radiolabeled glucocerebroside as the substrate, no differential sensitivity toward CBE was indicated, suggesting the presence of an additional, CBE-insensitive, beta-glucosidase in brain tissue. Residual glucocerebrosidase activity partially purified from the brain of an adult with type 1 Gaucher's disease was activated threefold by gluconoyl hydrazine, whereas the same enzyme from control brain was unaffected, and eight times less sensitive to gluconolactone inhibition.

Adult↗
PubMed1982

Partial purification and characterization of particulate acid phosphatase of Leishmania donovani promastigotes.

1. More than 90% of the total acid phosphatase activity in a sonicate of L. donovani promastigotes is contained in a particulate fraction (200,000 X g 30 min). The enzyme can be quantitatively extracted and solubilized with the aid of Triton X-100 (0.2 g/100 ml) and purified over 200-fold with 54% yield by chromatography on DEAE-Sephadex, QAE-Sephadex, Sepharose 4B and concanavalin-A Sepharose. 2. The phosphatase is a true acid hydrolase (pH optimum, 5.0-5.5) and has a rather broad substrate specificity; it will catalyze the hydrolysis of 4-methylumbelliferylphosphate, thymolphthalein diphosphate, pyridoxal phosphate, fructose 1,6-diphosphate, glucose 6-phosphate, glucose 1-phosphate, ADP and AMP. 3. It is a large (170,000 daltons in the presence of Triton X-100), stable and acidic enzyme (pI = 4.1) that has the electrophoretic mobility of a type zero or type 1 isoenzyme in acid (pH 4.3) polyacrylamide gels. 4. The enzyme is inhibited by sodium fluoride, 2-mercaptoethanol and mumolar amounts of a number of polyanionic molybdenum and heavy metal complexes that include the following: [C(NH2)3]4[(C3H7O3PO3)2Mo5O15] X 3H2O, [C(NH2)3]2[(C6H5)2AsMo4O15H] X H2O, (NH4)4[SiMo12O40] X H2O and (NH4)6[P2Mo18O62] X 9H2O. 5. L. donovani promastigotes contain very low levels of 10 other acid pH optimum hydrolytic enzymes, with the exception of modest levels of alpha-fucosidase.

Acid Phosphatase↗
PubMed1982

Metabolism of lysosomal enzymes in the protein-deficient weanling rat.

We have shown that the protein-deficient weanling rat fed a 3% casein diet, within 2 to 4 wk, exhibits marked changes in serum lysosomal hydrolases similar to those observed in children suffering from protein-calorie malnutrition: serum hexosaminidase, alpha-mannosidase, and beta-glucuronidase activities increase 3-fold, 2-fold, and 50%, respectively, whereas the acid phosphatase levels decrease by 50%. Rehabilitation of the protein-deficient animals with a diet containing 25% protein (i.e., casein) results in a rapid restoration of the plasma lysosomal hydrolase profiles to normal in less than 1 wk. The specific activities of various tissue lysosomal enzymes change significantly in the protein-deficient animals; however, no overall consistent pattern of change is apparent. In general, the greatest number of changes in lysosomal enzymes occurs in the kidney, whereas the brain exhibits the smallest differences between experimental and control animals in this regard. Perfusion experiments have shown that the rate of release of lysosomal enzymes from livers of rats fed the protein-deficient diet is profoundly altered when compared to that of control animals. Studies of the variation of enzyme secretion with time have demonstrated that the rate of secretion of hexosaminidase by the liver remains low and then rises markedly (3-fold) after the animals have been consuming the 3% casein diet for 16 days. In contrast, the secretion of both acid phosphatase and beta-glucuronidase is markedly depressed in the early phase of protein malnutrition (i.e., 7 to 16 days), and then increases greatly by the 3rd wk. These results demonstrate that changes occur in the rate of secretion of lysosomal enzymes by the liver during the course of experimental protein malnutrition.

Acid Phosphatase↗
PubMed1982

Enzymic differentiation of neurologic and nonneurologic forms of Gaucher's disease.

This study explores the biochemical basis that may distinguish neurologic and nonneurologic forms of Gaucher's disease. Crude membrane preparations from spleens of controls and patients representing the three clinical categories of Gaucher's disease were delipidated by extraction with sodium cholate and n-butanol. Total beta-glucosidase activity was estimated using 4-methylumbelliferyl-beta-D-glucopyranoside (MUG) as substrate, and glucocerebrosidase activity was determined using (3H)-glucocerebroside. beta-Glucosidase and glucocerebrosidase activities were reconstituted by inclusion of sodium taurocholate or phosphatidylserine in the assay medium. When assays contained phosphatidylserine, residual beta-glucosidase activity in delipidated spleen preparations from type 1, nonneurologic cases were five times greater than cases of neurologic Gaucher's disease (82.3 vs. 11.3 units per mg protein). However, beta-glucosidase assays using sodium taurocholate did not discriminate Gaucher's disease subtypes. Similar results were obtained when spleen preparations were analyzed for glucocerebrosidase using glucocerebroside as the substrate. Brain beta-glucosidase from patients representing the three classes of Gaucher's disease showed a similar pattern of sensitivity toward phosphatidylserine. The specific activity of beta-glucosidase in an extract of brain from the one case of type 1 Gaucher's disease analyzed was five times greater than the mean residual specific activity of brain beta-glucosidase measured in five cases of type 2 and type 3 Gaucher's disease. These findings suggest that, in patients with type 1 Gaucher's disease, glucocerebrosidase may show greater activity in the presence of acidic phospholipids than glucocerebrosidase does in patients with neurologic forms of the disease. The ability of the brain enzyme from a type 1 case to be profoundly stimulated by an acidic phospholipid may explain why such individuals are spared central nervous system involvement.

Adult↗
PubMed1982

Altered alpha-mannosidase isoenzymes in the liver in hepatic cirrhosis.

Homogenates of liver from cases of hepatic cirrhosis due to alpha 1-antitrypsin deficiency (PiZZ) alcoholism were analyzed for their content of various lysosomal enzymes. Also determined were the specific activities of lactate dehydrogenase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, and creatine phosphokinase in the extracts of liver from cases of both kinds of hepatic cirrhosis: all of these activities were within the range of control values. Similarly, the specific activities of the following lysosomal hydrolases were unremarkable: acid phosphatase, beta-mannosidase, beta-fucosidase, beta-glucuronidase and beta-glucosidase. Hexosaminidase specific activity was increased twofold in livers from the cases of cirrhosis due to alpha 1-antitrypsin deficiency. The specific activity of alpha-mannosidase (measured at pH 4.5) in homogenates of livers from PiZZ individuals with cirrhosis and those with alcoholic cirrhosis was increased two- to four-fold. Chromatography of the high-speed supernatant fraction from homogenates of livers of cirrhotic and noncirrhotic individuals on columns of DEAE-cellulose resolved alpha-mannosidase activity into two components: under the conditions employed, acid pH optimum (pH 4.5) alpha-mannosidase did not bind to the resin, whereas intermediate pH optimum (pH 5.5) alpha-mannosidase could be eluted with 0.1 mol/l NaCl. Liver from one case of (PiZZ) alpha 1-antitrypsin deficiency and emphysema, without demonstrable cirrhosis, was found to contain normal levels of both acid alpha-mannosidase and intermediate alpha-mannosidase. However, cases of cirrhosis due to alpha 1-antitrypsin deficiency contained twice as much acid alpha-mannosidase and only one third to one fourth as much intermediate alpha-mannosidase as controls. The deficiency in hepatic intermediate alpha-mannosidase was also observed in 5 of 5 cases of alcoholic cirrhosis.

Humans↗
PubMed1982

beta-Glucosidase assays in the diagnosis of Gaucher's disease.

The description in 1965 of glucocerebroside: beta-glucosidase as the enzymic defect in Gaucher's disease stimulated considerable research interest and effort toward establishing rapid, reliable, and inexpensive enzymic assays for diagnostic purposes and carrier detection. Here, we consider some of the methods currently in use in which the substrate is the synthetic glucoside, 4-methylumbelliferyl-beta-D-glucopyranoside, and leukocytes and fibroblasts are the sources of enzyme. We also consider the concepts of the "acid beta-glucosidase" and multiple forms of beta-glucosidase that have been proposed to explain the effectiveness of the fluorometric assays. Finally, we analyze the limitations of each method and discuss the difficulties involved in instituting heterozygote screening programs in the general population.

Clinical Enzyme Tests↗
PubMed1982

Effectors of three beta-glucosidases from human liver.

1. A third beta-glucosidase from human liver has been isolated using a mild (0.02-0.10%) Triton X-100 extraction of the exhaustively washed high speed (200,000 X g, 30 min) particulate fraction, QAE-Sephadex and concanavalin A-Sepharose chromatography. This new beta-glucosidase, referred to as TX beta-glucosidase, possesses a distinctive set of chemical properties such that it is similar to both, glucocerebrosidase and cytoplasmic beta-glucosidase, but it is not identical to either enzyme. 2. The TX beta-glucosidase hydrolyzes glucocerebroside as well as the beta-D-glucose, beta-D-galactose, beta-D-fucose, beta-D-xylose and alpha-L-arabinose derivatives of 4-methylumbelliferone. Like the cytoplasmic beta-glucosidase, the TX beta-glucosidase is inhibited by bile salts, and unaffected by conduritol B epoxide and heat stable activator protein. 3. All three beta-glucosidases were inhibited by N-hexylpsychosine, and all showed the same, mixed type inhibition kinetics, indicating a common hydrophobic binding site in all three enzymes. 4. The TX beta-glucosidase, which constitutes only a few percent of the total beta-glucosidase activity of human liver, is absent from liver from two cases of neurologic Gaucher disease and present in reduced amounts in a third case with CNS disease. Liver from a case of type 1 Gaucher disease contained normal amounts of the TX beta-glucosidase.

Bile Acids and Salts↗
PubMed1982

Vancomycin pharmacokinetics in patients undergoing chronic intermittent peritoneal dialysis.

The pharmacokinetics of vancomycin were studied during six episodes of peritonitis in four patients with chronic renal failure managed with chronic intermittent peritoneal dialysis. Following intravenous administration of vancomycin peritoneal concentrations ranged from undetectable to 22.5 micrograms/ml, and were 0-96% (mean 27%) of simultaneous serum concentrations. In view of the unpredictable penetration of vancomycin from serum into peritoneal fluid, we recommend that therapy for peritonitis due to staphylococci in patients undergoing peritoneal dialysis should include intraperitoneal administration of vancomycin.

Ascitic Fluid↗
PubMed1981

Purification and characterization of a cytosolic broad specificity beta-glucosidase from human liver.

A cytoplasmic beta-glucosidase has been isolated and purified 9,000-fold to homogeneity from the liver of a case of type 1 Gaucher's disease to a specific activity of 400,000 nmol/h/mg of protein. Although markedly elevated above control levels in this case of adult Gaucher's disease, the activity of this cytosolic liver enzyme was found to be markedly deficient in two cases of neurologic Gaucher's disease. The purification scheme employs QAE-Sephadex, DE52 cellulose, CM-Sephadex, hydroxylapatite, and Cibacron blue-Sepharose chromatography, and preparative isoelectric focusing. The beta-glucosidase preparations isolated from the liver of the case of adult Gaucher's disease and control liver have similar physical properties. Both enzymes have a molecular weight of approximately 53,000, sw,20 of 4.3, pI of 4.5-4.6, a pH optimum between 5 and 6, and a high affinity for 4-methylumbelliferyl-beta-D-glucopyranoside (Km = 0.06-0.07 mM). The enzymes from both sources also have a broad specificity and will hydrolyze the 4-methylumbelliferyl derivatives of beta-D-galactose, beta-D-fucose, beta-D-xylose, and alpha-L-arabinose in addition to several aryl-galactosides and steroid-glucosides. The cytoplasmic beta-glucosidase will not hydrolyze glucocerebroside and shows no cross-reactivity with antibodies prepared against lysosomal glucocerebrosidase. Both cytoplasmic beta-glucosidase and glucocerebrosidase will hydrolyze 17 beta-estradiol-17'-beta-D-glucose, and the activity of both enzymes on this substrate is increased more than 15-fold in the presence of the Gaucher spleen heat-stable factor. The role of this cytoplasmic beta-glucosidase in the etiology of Gaucher's disease and its possible relationship to lysosomal glucocerebrosidase are discussed.

Cytosol↗