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Biomedical subjects

K Adriaenssens

Publications and source records attributed to K Adriaenssens.

At least 19 recordsLinked to original sources

Characteristics of human intestinal acid sialidase.

With methylumbelliferyl-N-acetyl-neuraminic acid (MU-NANA) as substrate, acid sialidase was determined in intestinal biopsies of children. The enzyme has an acid pH optimum, a Km value of 4 mmol/l and a pronounced thermal lability which can be partially prevented by the addition of albumin. N-acetyl-neuraminic acid (NANA) and derivatives as well as other glycoprotein and oligosaccharide sialidase substrates inhibit sialidase whereas gangliosides have no effect. This could be an indication that intestinal MU-NANA sialidase is different from ganglioside sialidase as has been reported for many other tissues.

Adolescent↗

Hyperargininemia: the rat as a model for the human disease and the comparative response to enzyme replacement therapy with free arginase and arginase-loaded erythrocytes in vivo.

Rat erythrocytes lack arginase as do the erythrocytes of human homozygote patients with hyperargininemia due to arginase deficiency. The rat has physiological liver arginase activity and plasma arginine and ornithine levels between the homozygotes and the heterozygotes with hyperargininemia. In rats, one injection of free arginase induces a transient exogenous arginase effect which is abolished after 24 hr. One injection of isoionic arginase-loaded erythrocytes provokes an exogenous arginase effect in physiological "hyperargininemic" rats and pathological "hyperargininemic"-made rats for at least 8 and 5 days respectively. The very transient response in vivo to exogenous free arginase can be considerably prolonged by entrapment of the arginase in isoionic prepared erythrocytes.

Amino Acid Metabolism, Inborn Errors↗

Serum pancreatic lipase as a screening test for cystic fibrosis.

Pancreatic lipase catalyses the hydrolysis of emulsified triglycerides to form a transparent solution of monoglycerides and fatty acids. Levels of serum pancreatic lipase were measured in neonates known to have cystic fibrosis and compared with levels in control infants. During the first weeks of life infants with cystic fibrosis had raised serum pancreatic lipase values in parallel with raised serum trypsin values. A simple and specific turbidimetric dried blood spot assay for serum pancreatic lipase was used as a screening test fo cystic fibrosis in the neonate.

Cystic Fibrosis↗

Simple electrophoretic technique for creatine kinase MM isozyme in neonatal Duchenne muscular disease screening using dried blood samples.

By increasing diadenosine pentaphosphate to a final concentration of 75 mumol to 100 mumol/l to inhibit excess adenylate kinase, a highly sensitive substrate in a gelatin matrix allowed the developement of a simple and cheap electrophoretic technique for creatine kinase MM isozyme in dried blood samples. The method is suitable for neonatal Duchenne muscular dystrophy screening, and it is an alternative method for a previously described bio-luminescent assay, which requires special equipment.

Adenine Nucleotides↗

Arginase and free amino acids in hyperargininemia: leukocyte arginine as a diagnostic parameter for heterozygotes.

Arginase activity and free amino acids were measured in plasma, erythrocytes and leukocytes of patients with hyperargininemia and in controls. There is no arginase activity in the leukocytes and erythrocytes of homozygous patients; in heterozygotes it is normal to low. The activity is 50 to 100 times higher in leukocytes than in erythrocytes. In controls as well as in patients and heterozygotes, the amino acid concentrations are higher in leukocytes than in plasma and erythrocytes. In addition to the increased arginine in the three blood compartments (the result of an arginase deficiency), there is also an obvious decrease of aspartic acid in the erythrocytes of the patients. The arginine concentration in leukocytes of heterozygotes is as high as in homozygotes and can therefore be used as a diagnostic parameter for heterozygotes.

Amino Acid Metabolism, Inborn Errors↗

Use of enzyme-loaded erythrocytes in in-vitro correction of arginase-deficient erythrocytes in familial hyperargininemia.

The capacity of arginase-deficient erythrocytes of patients with familial hyperargininemia to produce urea and to catabolize arginine can be increased in vitro by introducing human liver arginase into their erythrocytes. The results of this study on a specific human model show that it is possible to change the metabolic function of a genetically defective erythrocyte by incorporating exogenous human enzyme. The in vivo application of enzyme-loaded erythrocytes for enzyme replacement therapy of inborn metabolic errors in humans must await in vivo studies on animal models.

Amino Acid Metabolism, Inborn Errors↗