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Biomedical subjects

E Beutler

Publications and source records attributed to E Beutler.

At least 415 records · Page 23Linked to original sources
PubMed1977

Enzyme replacement therapy in Gaucher's disease: preliminary clinical trial of a new enzyme preparation.

A patient with far-advanced adult type Gaucher's disease was treated with solubilized, highly purified placental glucocerebrosidase administered after entrapment in human erythrocytes or by direct intravenous injection. In some instances the enzyme-containing erythrocytes were coated with gamma globulin. No toxic side effects were observed after enzyme infusion. There were suggestive, but not conclusive, findings that enzyme infusion may have been beneficial. After therapy, there was a decrease in transfusion requirement, some improvement of liver function, possible decrease in liver size, and relief of subjective symptoms. Erythrocyte and plasma glucocerebroside levels were unchanged during therapy, but there was a possibly significant decrease in leukocyte and platelet levels of the glycolipid. No changes occurred in serum acid phosphatase or angiotensin-converting enzyme activity.

Acid Phosphatase↗
PubMed1977

Purification and properties of human erythrocyte pyrimidine 5'-nucleotidase.

A 250,000-fold purification of pyrimidine 5'-nucleotidase from human erythrocytes has been achieved using a combination of DEAE-cellulose chromatography, ammonium sulfate fractionation, gel filtration, and isoelectric focusing. Polyacrylamide disc and starch gel electrophoresis of the purified material show two strong protein bands. On starch gel these bands exhibited pyrimidine 5'-nucleotidase activity. Two faint protein bands devoid of enzyme activity were also found in the case of polyacrylamide electrophoresis. The enzyme has a pH optimum at 7.5 and is most stable between pH 6 and 7.5. The enzyme has pI of 5.0 and a molecular weight of 28,000 by gel filtration. The Km of the purified enzyme was 10 muM, compared to 40 muM when measured in hemolysate. The higher Km in the hemolysate is due to the presence of an inhibitor. Inorganic phosphate was shown to be a competitive inhibitor of pyrimidine 5'-nucleotidase and inorganic phosphate in the hemolysate may be responsible for increasing the Km of the enzyme for the substrate cytidine monophosphate.

Erythrocytes↗
PubMed1977

Instability of the oxy form of sickle hemoglobin and of methemoglobin in isopropanol.

Oxygenated hemoglobin from water-lysed sickle erythrocytes preciptated more rapidly than hemoglobin from normal cells when exposed to 17% isopropanol in 0.1 M tris, pH 7.4, buffer (the isopropanol solubility test of Carrell and Kay). Precipitates became visible after approximately 20 minutes of incubation with SS, AS, or SC blood, while AC hemoglobin and normal adult A hemoglobin required 40-60 minutes of precipitate. Methemoglobin comprised less than 1.5% of the total hemoglobin present in all samples under study. Significant preciptation of methemoglobin did not occur unless methemoglobin levels were greater than 8%. Solubilization of the precipitate in 6M urea-barbital buffer and subsequent electrophoresis demonstrated that the insoluble material was sickle hemoglobin (Betas chain). The results of these experiments confirm previous findings indicating that even fully oxygenated sickle hemoglobin is unstable.

1-Propanol↗
PubMed1977

The tissue distribution of hexosaminidase S and hexosaminidase C.

The proportion of hex S to hex C in normal and Sandhoff's fibroblasts was determined to be between 1:1 and 1:2 by differential staining of hex S at pH 4.4 with 4-methylumbelliferyl-beta-N-acetylgalactosaminide and of hex C at pH 7.0 with 4-methylumbelliferyl-beta-N-acetylglucosaminide. Hex S and hex C were also semi-quantitated in various normal tissues--brain, liver, spleen, heart, kidney, intestine, placenta, skeletal muscle and fibroblasts. Hex C was most prominent in brain and, somewhat less so, in liver, skeletal muscle and fibroblasts. The greatest amount of hex S activity was found in fibroblast, but it was also observed in lesser amounts in liver, kidney, intestine and placenta.

Electrophoresis↗
PubMed1977

G-6-PD Long Prairie: a new glucose-6-phosphate dehydrogenase mutant exhibiting normal sensitivity to inhibition by NADPH and accompanied by nonspherocytic hemolytic anemia.

The enzymatic properties of a new glucose-6-phosphate dehydrogenase (G-6-PD) variant (G-6-PD Long Prairie) were studied in a white patient with chronic nonspherocytic hemolysis. The red cells were found to have 2.3%-7.7% normal enzymatic activity. The mutant enzyme exhibited marked heat instability, an increased pH optimum, a moderately decreased Km for G-6-P, and increased utilization of 2-deoxyglucose-6-phosphate and deamino NADP. The Km for NADP and Ki for NADPH were both normal. G-6-PD Long Prairie is an interesting new G-6-PD variant that demonstrates that chronic hemolysis can be associated with modestly decreased G-6-PD activity despite normal sensitivity to inhibition by NADPH. Although increased sensitivity to inhibition by NADPH has been postulated to decrease intracellular enzyme activity, resulting in enhanced susceptibility to hemolysis in certain G-6-PD variants with only moderately decreased enzymatic activity, an alternative mechanism of hemolysis, possibly enzyme thermolability, exists in G-6-PD Long Prairie.

Adult↗
PubMed1977

Prolonged maintenance of 2,3-DPG in liquid blood storage: use of an internal CO2 trap to stabilize pH.

A close relationship exists between the decrease in concentration of 2,3-diphosphoglycerate (2,3-DPG) and a fall in the pH of stored blood. Buffering the stored red cells with bicarbonate is one solution to the problem of maintaining pH during storage. The effectiveness of this buffer depends upon loss from the stored blood of carbonic acid in the form of CO2. We describe a system in which the CO2 is trapped in a small internal package which contains calcium hydroxide, or calcium hydroxide embedded in Silastic. A medium containing bicarbonate, adenine, glucose, phosphate and mannitol (BAGPM) is added after initial packing of the erythrocytes. With this approach, it has been possible to maintain 2,3-DPG at 92 percent of original, and ATP was approximately 62 percent of initial levels at the end of 42 days of storage if an internal Silastic bag containing calcium was used in bags agitated once weekly. More frequent agitation (five times weekly) produced acceptable maintenance of both 2,3-DPG (78 percent of original) and ATP (44 percent of original) after 42 days of storage when a Silastic block impregnated with calcium hydroxide was utilized to absorb CO2.

Adenosine Triphosphate↗
PubMed1977

Glucose-6-phosphate dehydrogenase deficiency and red cell glutathione peroxidase.

The activity of glutathione peroxidase (GSH Px), glucose-6-phosphate dehydrogenase (G-6-PD), hexokinase, and glutamic oxaloacetic transaminase (EGOT) was measured in 78 blood samples. GSH Px activity was not found to correlate with hexokinase or EGOT activity, indicating that it was not a strongly age-dependent enzyme. Although modest elevations of GSH Px activity were observed in the red cells of patients with a variety of hematologic disorders, the most consistent and striking increases in activity were observed in G-6-PD-deficient subjects.

Aspartate Aminotransferases↗
PubMed1977

Maintenance of low screen filtration pressure in blood stored in a new liquid medium: BAGPM.

Formation of microaggregates in blood stored in conventional media is reflected by rapidly rising screen filtration pressure (SFP). We show that the BAGPM (bicarbonate, adenine, glucose, phosphate, and mannitol) blood preservation system maintains SFP at near normal levels throughout the storage period of 42 days. Whenever the SFP had a tendency to rise in BAGPM blood, filtration through a routine in-line blood filter reverted SFP back to baseline levels. Blood from the same donors stored in citrate-phosphate-dextrose (CPD) adenine had a rapidly rising SFP by 7 to 14 days of storage. Filtration through the routine blood filter had no effect on the SFP of blood stored in CPD-adenine, CPD, or ACD. BAGPM not only maintains adequate levels of ATP and 2,3-diphosphoglyceric acid (2,3-DPG) during full 42 days of storage but also offers a unique system in which microparticulate material is prevented from forming, with maintenance of low SFP, perhaps because of its low leukocyte, platelet, and fibrinogen content.

Blood Preservation↗
PubMed1977

A simple rapid radiometric assay for pyrimidine-5'-nucleotidase.

Pyrimidine-5'-nucleotidase deficiency appears to be an important cause of hemolytic anemia associated with basophilic stippling of the red cells. A new radiometric method for the assay of this enzyme has been developed. In this technique, 14C-CMP serves as substrate. The CMP which is not dephosphorylated to cytidine is bound to the barium sulfate precipitate which forms in the deproteinization process. The cytidine remains in solution and is counted. The method is simple and reproducible and can be carried out on large numbers of samples. Two patients with pyrimidine-5'-nucleotidase deficiency have been detected by means of this technique.

Anemia, Hemolytic↗
PubMed1977

Refractory sideroblastic and nonsideroblastic anemia: a review of 27 cases.

A study was done with 27 patients who met the following criteria: (1) anemia, (2) cellular bone marrow not diagnostic of leukemia, (3) absence of underlying disease that could account for the hematologic abnormalities at time of initial study and (4) absence of iron, B(12) or folate deficiency. Of the 27 patients, 13 had ringed sideroblasts and 14 did not. Eleven patients received corticosteroids, 18 received folate, 23 pyridoxine and 12 androgens. Two partial responses occurred in the sideroblastic group and were attributed to androgen therapy in one patient and pyridoxine therapy in the other. In the nonsideroblastic group, two partial responses occurred which were attributed to prednisone therapy. Transfusions were required in 23 patients. Leukemia developed in six patients. It is concluded that currently used treatments have little effect on refractory anemia and that in most patients continuing transfusions are required. In a small percentage of patients, there is transformation to leukemia.

Adolescent↗
PubMed1977

Increased glutathione peroxidase activity in alpha-thalassemia.

Glutathione peroxidase (GSHPx) activity was found to be greatly elevated in members of a family with alpha-thalassemia. Eleven other families with proven alpha-thalassemia were investigated, and all but one subject with hemoglobin H disease had increased red cell GSHPx. Most persons with alpha-thalassemia trait also had increased activity of red cell GSHPx. In contrast, only very modest increases in glutathione peroxidase activity were observed in subjects with various forms of beta-thalassemia.

Chemical Phenomena↗
PubMed1976

The subunits of human hexosaminidase A.

Previous studies of the subunit structure of hexosaminidase gave ambiguous results, but suggested that the enzyme was composed of six equally sized subunits. Dissociation of hexosaminidase A with p-chloromercuribenzoate produces an alkylated fragment with mol.wt. approx. 50000, which is converted into hexosaminidase S by treatment with dithiothreitol. Treatment of native hexosaminidase A with sodium dodecylsulphate results in the formation of a large and a small fragment. However, although the native enzyme has a sedimentation coefficient of 5.8S, dissociation by S-carboxymethylation and maleic anhydride treatment results in subunits exhibiting a single schlieren boundary on analytical ultracentrifugation with a sedimentation coefficient of 2.18S. These results indicate that the enzyme is composed of four subunits, each with molwt. approx. 25000-27000. The mol.wt. of the native enzymes is calculated to be approx. 110000. Our data are consistent with the subunit structures of hexosaminidases A, B and S as being alpha2beta2, beta4 and alpha4 respectively.

Electrophoresis, Polyacrylamide Gel↗