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Biomedical subjects

A Lowenthal

Publications and source records attributed to A Lowenthal.

At least 127 records · Page 7Linked to original sources

Biochemical findings in multiple sclerosis. III. Immunoglobulins of restricted heterogeneity and light chain distribution in cerebrospinal fluid of patients with multiple sclerosis.

Several biochemical parameters, the most important of which are total IgG, kappa and lambda light chain distribution and thin layer isoelectric focusing, were determined in the cerebrospinal fluid of 36 multiple sclerosis patients. Their ages and the evolution period of their disease are widely spread and no sex differentiation was made.

Adult↗

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↗

Excretion of guanidino-derivates in urine of hyperargininemic patients.

Quantitative determinations were made for seven guanidino-derivates in urine of patients affected with hyperargininemia, lysine cystinuria, healthy children and adults, goats and monkey. The amount of all seven guanidino-derivates excreted in the urine with the exception of guanidino-succinic acid was large in the case of hyperargininemic patients. Guanidino-succinic acid is found in traces in the urine of these patients, even after arginine loading tests. There is apparently no similarity concerning the guanidino-derivates between the patients with hyperargininemia, a pathological status, and the arginase deficiency in goats and monkeys, a physiological phenomenon.

Adult↗

Unsuccessful trial of gene replacement in arginase deficiency.

The Shope virus following cutaneous inoculation produces skin papillomas in rabbits and induces a virus-coded arginase in the squameous epithelium of these papillomas. The only discernible effect of the virus inoculated intravenously in rabbits and other animals was a decrease of the serum arginine concentration. Intravenous injection in 3 hyperargininemic patients, however, did not influence the underlying metabolic disease.

Amino Acid Metabolism, Inborn Errors↗

Familial hyperargininaemia.

A third case of hyperargininaemia occurring in one family was studied from birth. In cord blood serum arginine concentration was only slightly raised, but arginase activity in red blood cell haemolysates was very low. In the urine on day 2 a typical cystinuria pattern was present. Arginine concentration in serum increased to 158 mumol/100 ml on the 41st day of life. Later determinations of the arginase activity in peripheral blood showed values below the sensitivity of the method. Blood ammonia was consistently high, and cystinuria was present. The enzymatic defect was further displayed by intravenous loading tests with arginine. Serum urea values were predominantly normal or near the lower limit of normal, suggesting the presence of other metabolic pathways of urea synthesis. In urine there was no excretion of guanidinosuccinic acid, while the excretion of other monosubstituted guanidine derivatives was increased, pointing to a connexion with hyperargininaemia. Owing to parental attitude, a low protein diet (1-5 g/kg) was introduced only late. The infant developed severe mental retardation, athetosis, and spasticity.

Amino Acids↗

The chemical composition of idiopathic nonarteriosclerotic cerebral calcifications.

Calculi from a case of cerebral idiopathic nonarteriosclerotic calcification (Fahr's disease) were examined. The stone consists of hydroxyapatite and possesses a typical structure: the calcification process seems to be initiated by the formation of small round bodies that are cemented to each other to form the final stone. Calcified vessels are also present, but seem to be a secondary effect. From a comparison with other calcifications, it is concluded that no pathologic significance should be attached to the relatively high levels of trace metals such as zinc, iron, copper, magnesium, lead, and others, with the possible exception of manganese. The organic matrix of the stone contains large quantities of protein. On hydrolysis of this fraction, an important unidentified ninhydrin-positive peak was found. No mucopolysaccharides were found.

Activation Analysis↗

Bound and free light chains in subacute sclerosing panencephalitis and multiple sclerosis serum and cerebrospinal fluid.

The kappa-lambda light chain ratios, the presence of free light chains and the double ring formation, with antikappa and antilambda serum, in single radial immunodiffusion were investigated in serum and cerebrospinal fluid of patients with subacute sclerosing panencephalitis. Cerebrospinal fluid samples of several multiple sclerosis cases were considered simultaneously. The results obtained suggest special immunoglobulin synthesis in both diseases.

Immunodiffusion↗

Structural homogeneity of human subacute sclerosing panencephalitis antibodies.

Three homogeneous immunoglobulin fractions were isolated from the serum of a patient with subacute sclerosing panencephalitis (SSPE). All three fractions reacted in immunodiffusion with measles and SSPE virus preparations. The amino-terminal sequence of the light and heavy chains of one of the antibody fractions was determined by automated Edman degradation. A single amino acid residue was obtained at every step, confirming the homogeneity of this human antibody.

Amino Acid Sequence↗