J.A. Cabezas

Increased serum α-l-fucosidase and β-N-acetylglucosaminidase activities in diabetic, cirrhotic and gastric cancer patients

The activities of several glycosidases (α-l-fucosidase, α-D-mannosidase, α-D-galactosidase, β-d-gaIactosidase, β-N-acetylglucosaminidase and β-d-glucuronidase) were determined in human sera from 10 normal subjects and in three groups each of 10 patients with diabetes mellitus, hepatic cirrhosis and gastric carcinoma. The results show significantly higher activities in the patients for α-l-fucosidase (p < 0.001) and for β-N-acetylglucosammidase (p < 0.1, p < 0.001 and p < 0.05, respectively), and smaller or not significantly greater values for the other glycosidases.

Serum β-N-acetylglucosaminidase, β-d-glucosidase, α-d-glucosidase, β-d-fucosidase, α-l-fucosidase and β-d-galactosidase levels in acute viral hepatitis, pancreatitis, myocardial infarction and breast cancer

Abstract The specific activities of several glycosidases ( β - N -acetylglucosaminidase, β- d -glucosidase, α- d -glucosidase, β- d -fucosidase, α- l -fucosidase and β- d -galactosidase) were determined in human sera from a control group of 10 normal subjects and in four groups, each of 10 patients, with acute viral hepatitis, acute pancreatitis, acute myocardial infarction and breast cancer. The results show significantly higher activities in acute viral hepatitis for β - N -acetylglucosaminidase, β- d -glucosidase and α- d -glucosidase ( p p d -glucosidase ( p d -fucosidase and α- l -fucosidase ( p β - N -acetylglucosaminidase, β- d -glucosidase, α- d -glucosidase, β- d -fucosidase and β- d -galactosidase ( p p p p p β - N -acetylglucosaminidase ( p

N-Acetyl β-d-glucosaminidase and α-l-fucosidase activities in relation to glycosylated hemoglobin levels and to retinopathy in diabetes

Abstract N -Acetyl β- d -glucosaminidase and α- l -fucosidase were determined in human sera from 25 control subjects, in 23 diabetic patients without retinopathy and in 22 diabetic patients with retinopathy. The results show significantly higher N -acetyl β- d -glucosaminidase activity in diabetic patients independently of the development of retinopathy and also independently of the length of diabetes. No correlation was found between either serum enzymes and serum glucose concentration and glycosylated hemoglobin (HbA,).

Variation in serum arylesterase, β-glucuronidase, cathepsin L and plasminogen activators during pregnancy

To determine whether the activities of certain hydrolases (arylesterase, beta-glucuronidase, cathepsin L, plasminogen activators, arginase, glutaminase, asparaginase and adenosine deaminase) are changed during pregnancy, three groups of 15 apparently healthy women (aged 18-38 years) in their first, second and third trimester of pregnancy were compared to a control group formed of 15 non-pregnant women of similar ages. Enzyme and specific activities gradually increased from the first to the end of the third trimester of pregnancy for arylesterase and beta-glucuronidase, these increases being statistically significant (P < 0.01) in comparison to controls. However, as regards cathepsin L and plasminogen activators, the greatest increase was found in the second trimester. Arginase, glutaminase and asparaginase activities were very low and not distinguishable from the controls. In conclusion, differences in the activities of several hydrolases have been found in the sera of healthy pregnant women in comparison to controls.

Serum glycosidases in diabetes mellitus in relation to the retinopathy and to the length of the disease

The following glycosidase activities in sera have been studied: alpha-D-mannosidase, beta-D-glucuronidase, N-acetyl-beta-D-galactosaminidase, alpha-D-galactosidase, beta-D-galactosidase, alpha-D-glucosidase, beta-D-glucosidase and beta-D-fucosidase, in diabetic patients in relation to the presence of microangiopathy, evident by retinopathy, and to the length of the disease. A significant increase of all the enzyme activities, except for alpha-D-galactosidase was found. These elevations were independent of the development of retinopathy and the duration of the diabetic process.

β-Fucosidase, β-glucosidase and β-galactosldase activities associated in bovine liver☆

Abstract 1. 1. β- d -Fucosidase, β- d -glucosidase and β- d -galactosidase activities from bovine liver are associated in a single peak in isoelectric focusing. The isoelectric point is 4.35 for all these activities, suggesting that they are catalyzed by the same enzyme. 2. 2. This enzyme shows the optimal pH in the range 4.5–6.5 for all the above mentioned activities. 3. 3. The Km and Vmax are 0.26 mM and 31 mU mg−1, 0.10 mM and 24 mU mg−1, and 0.30 mM and 20 mM mg−1 for the p-nitrophenyl-fucoside, -glucoside and -galactoside, respectively. The glucoside derivative is the best substrate, with a Vmax/Km value of 0.24 mlβmg−1βmin−1. 4. 4. The Lineweaver-Burk profiles are convex upward in most cases, suggesting a substrate-activation model, and the presence of more than one binding site in the enzyme. 5. 5. The Ki for all the activities were determined with p-fucose, glucose and galactose as inhibitors. d -Fucose is the strongest inhibitor. The inhibition is competitive in all cases.

Ganglioside alterations in various brain areas, liver and kidney from chronic alcoholic rats

Ethanol was administered to Wistar male rats for 4 or 10 months and to female rats for 21 2 months (including gestation), using a 20% ethanol-water solution as the only fluid. Gangliosides (expressed as NeuAc) from forebrain, cerebellum, brain stem, liver and kidney of the alcoholic rats and their newborns were determined by densitometry. Forebrain and liver from males showed a statistically significant increase in their ganglioside-NeuAc content after 4 months of alcohol ingestion. In addition, when the treatment lasted up to 10 months the increase was larger. In contrast, a significant decrease of cerebellar and kidney ganglioside-NeuAc content was found after 10 months. The ganglioside pattern of the different sources displayed a variable profile. Moreover, while alcohol fed mothers showed a significant increase in the ganglioside-NeuAc content of cerebellum and liver, and a decrease in the brain stem, newborns of mothers given alcohol in their drinking water exhibited an increase of ganglioside-NeuAc content in cerebellum, liver and kidney and a decrease in forebrain.

A fluorometric procedure for measuring the neuraminidase activity: Its application to the determination of this activity in influenza and parainfluenza viruses

A fluorometric procedure for quantitating the amount of N-acetylneuraminic acid enzymatically released by the neuraminidase activity from N-acetylneuraminyl-lactose (sialyl-lactose) has been developed. The liberated lactose is hydrolyzed with beta-galactosidase, and the released galactose is oxidized with galactose dehydrogenase and NAD+; finally, the NADH produced is measured by fluorometry (excitation at 340 nm and analysis of emitted light at 465 nm). The fluorometric assay is about 10-fold more sensitive than the spectrophotometric procedure that measures NADH at 340 nm. It readily measures amounts as little as 2 nmol of sialic acid, and does not require the use of radioactive isotopes. Interferences due to sucrose or other substances, which cause errors in some cases with the use of the periodate-thiobarbiturate method for neuraminidase activity determination, are avoided. The procedure reported here provides a sensitive, rapid, and relatively simple method (feasible with commercialized reagents) for measuring the neuraminidase activity not only in purified samples from different sources but also directly in biological materials such as viruses. The technique has been tested with some viruses recently isolated belonging to Orthomyxoviridae or Paramyxoviridae families, known to be rich in neuraminidase. Reciprocally, this method can also be employed for determining the sialic acid concentration in acylneuraminyl-lactose-containing compounds when using purified neuraminidase for hydrolysis.

Hydrolytic enzyme activities, mainly from lysosomal localization, in sera from patients who ingested a toxic oil

Some hydrolytic enzyme activities, mainly typical of lysosomal localization, have been determined in blood sera from patients who ingested a rapeseed oil (denatured with anilines and treated by a thermal process), and in healthy subjects. beta-N-Acetylglucosaminidase, beta-D-glucosidase, beta-D-glucuronidase, alpha-L-fucosidase and leucine aminopeptidase activities were significantly higher when compared with controls (p less than 0.001); higher activities but not significant (p less than 0.2) differences were found for alpha-D-mannosidase and alkaline phosphatase. In contrast, beta-D-galactosidase, alpha-D-galactosidase, acid phosphatase and lipase showed lower activities than controls. The significance of these results is discussed.

Rearrangement of aminophospholipids in bilayers from sheep platelet plasma membranes and platelet liposomes by increasing their cholesterol levels

Phospholipid orientation in platelet plasma membranes and other blood cells, such as erythrocytes, appears to be rather similar. The negatively charged phospholipids are almost exclusively located on the inner leaflet of the bilayer. No phosphatidylserine is present on the outer membrane bilayer. The results of the present study, using a specific reagent for amino groups, trinitrobenzenesulfanilic acid, showed that in sheep platelet plasma membranes enriched with free exogenous cholesterol, an alteration in the aminophospholipid topology occurs, with a portion of phosphatidylserine moving from the inner to the outer side. A progressive appearance of aminophospholipids in the outer membrane bilayer was also observed in artificial vesicles prepared with total lipids from sheep platelets supplemented with increased amounts of free cholesterol.