Search PubMed⌕ Search

Biomedical subjects

W Gerok

Publications and source records attributed to W Gerok.

At least 325 records · Page 18Linked to original sources
PubMed1979

[Glycoproteins: their biological and clinical significance. I (author's transl)].

Increasing knowledge on structure, biosynthesis and catabolism of glycoproteins have given new insights on the patho-biochemical and clinical significance of these macromolecules. The most important results and conclusions are summarized in this review. 1. The terminal sugars of glycoproteins--N-acetylneuraminic acid (NANA) and L-fucose--as well as the penultimate galactose molecule have important functions in cell interaction, adhesion and recognition. Moreover, these carbohydrates mediate the migration and distribution of cells and it is believed that they are essential part of the feto-maternal "immunological barrier". 2. Evidence indicating that the composition and pattern of plasma membrane glycoproteins is associated with tumour growth and metastatic formation is accumulating. Moreover, the determination of serum glycosyltransferase activity is gaining increasing interest, because the level of these enzymes is substantially elevated in patients with neoplastic disease. 3. Diseases of the autoimmunosystem are likely linked to a disturbed glycoprotein metabolism. The clinical importance is underlined by studies on immunotherapy of tumours.

Autoimmune Diseases↗
PubMed1979

Variability of bacterial gene-directed enzyme production in human genetically deficient cells.

Human beta-galactosidase-deficient skin fibroblasts from a patient with generalized gangliosidosis (GMI-gangliosidosis type I) were treated with phage lambda plac DNA, coding for Escherichia coli beta-galactosidase (beta-D-galactoside galactohydrolase, EC.3.2.1.23). New beta-galactosidase activity detected in cell extracts of phage DNA-treated GMI-gangliosidosis fibroblasts continued to vary considerably from one experiment to another. It behaved like the E. coli z-gene product upon immunochemical and physicochemical investigation. In some experiments the antigenic behavior of resultant beta-galactoside activity in lambda plac DNA-treated cells resembled that of mutant E. coli beta-galactosidase. Among the factors and variables that may be responsible for the variation in the results obtained here and elsewhere, low physical binding between prokaryotic mRNA sequences and fibroblast ribosomal RNA could play a part connected with effective translation. This hypothesis is discussed under the aspect of a comparison of the ribosomal binding site of lac z mRNA with the 3'-terminus of the eukaryotic 18s ribosomal RNA, which shows limited possibilities for base-pairing interactions. More extensive possibilities for forming Watson-Crick base pairs between their initiation site and the eukaryotic ribosomal binding site exist for other prokaryotic messengers, such as those of Q beta-replicase, f 1-coat protein, or UDPG-4-epimerase.

Cells, Cultured↗
PubMed1979

Bile salt binding to serum components. Taurocholate incorporation into high-density lipoprotein revealed by photoaffinity labelling.

1. Photoaffinity labelling of human serum albumin with the sodium salts of (3 beta-azido-7 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oyl)-2-amino[2(-3)H (N)]ethanesulfonic acid, (7,7-azo-3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oyl)-2-amino[2(-3)H (N)]ethanesulfonic acid and (11 zeta-azido-12-oxo-3 alpha,7 alpha-dihydroxy-5 beta-cholan-24-oyl)-2-amino[2(-3)H (N)]ethanesulfonic acid resulted, in each case, in a considerable covalent incorporation of radioactivity into the protein. 2. Photoaffinity labelling of whole serum, obtained from fasting test persons, revealed with all three photolabile derivatives of taurocholate at the physiological concentration of 2.1 microM the incorporation of radioactivity not only into albumin but also into high-density lipoprotein, as demonstrated by density gradient centrifugation and by immunological characterization. 3. The bulk of radioactivity incorporated into high-density lipoprotein by photoaffinity labelling of whole serum was found to have been associated with the lipids. Only 10-20% of the label was covalently bound to apolipoproteins, predominantly to the apolipoproteins A-I and A-II. 4. The interaction of taurocholate with high-density lipoprotein has been confirmed by density gradient centrifugation using 14C-labelled taurcholate. It is assumed that the interaction of taurocholate with high-density lipoprotein is physiologically of significance.

Adult↗
PubMed1979

[Toxicity of ammonium acetate in rats with acute and subacute galactosamine-induced hepatitis (author's transl)].

Ammonia toxicity and the protective effect of arginine thereon were investigated in rats after single and repeated doses of galactosamine. Urea cycle enzymes and ornithine-oxo-acid transaminase activities were measured in rat liver homogenates. Ammonium acetate proved to be less toxic in rats treated with single or repeated doses of galactosamine than in untreated animals. Urea cycle enzyme activities of galactosamine-treated rats were clearly lowered. The protective effect of arginine against lethal ammonia intoxication was found in animals that had been treated with galactosamine as well as in untreated rats. Since the toxicity of ammonium acetate is lower in rats with galactosamine hepatitis, in which the activities of the liver urea cycle enzymes are reduced, it seems likely that ammonia detoxication in galactosamine-poisoned rat liver partly bypasses the urea cycle.

Acetates↗
PubMed1978

Decrease of human serum fucosyltransferase as an indicator of successful tumor therapy.

Surgical removal of colon carcinomas leads to a decrease in the rate of incorporation of [14C]fucose into its endogenous acceptor in human serum; normal incorporation rates are attained within 14 days. A similar time course has been determined for alpha2- and alpha3-fucosyltransferase when either desialo- or desialodegalactofetuin are employed as exogenous acceptors. A correlation has also been seen between transferase activity and the therapeutic response of patients with breast cancer. These results indicate that the determination of fucosyltransferase activity can facilitate the diagnosis of neoplasia, and the success of surgery, chemotherapy, or radiation.

Aged↗
PubMed1978

[Purine nucleotide synthesis in human liver an its influence by benzbromarone (author's transl)].

5-Phosphoribosyl-1-pyrophosphate amidotransferase and the hypoxanthine-guanine phosphoribosyltransferases (H-PRT, A-PRT) were assayed in human liver cells and some of the properties of these enzymes were determined. The Michaelis-Menten constants of both H-PRT and A-PRT for phosphoribosylpyrophosphate are at least an order of magnitude lower than for human PP-ribose-P amidotransferase. At the enzyme level the higher specific activities of phosphoribosyltransferases would, in effect, give precedence to purine salvage in human liver. In addition, no effect of benzbromaronum on enzyme activities could be demonstrated.

Amidophosphoribosyltransferase↗
PubMed1978

Serum alanine assay with an enzymic micromethod (L-alanine dehydrogenase).

L-Alanine was measured by an enzymic micromethod in serum after treatment with perchloric acid, as well as after ultrafiltration through collodium membrane filters. Serum L-alanine was also determined by an automated column chromatographic technique. Using the enzymic method, spuriously increased L-alanine levels could be obtained due to the absorbent reaction between hydrazine and NAD-containing reagents. It could be shown that this absorbent reaction depends on the pH value of the test solution. In contrast to supernatant diluted by perchloric acid, ultrafiltrates gave L-alanine data equivalent to those by column chromatography, since conditions of reaction time and pH value could be kept identical for blank, standard and ultrafiltrate solutions.

Adult↗
PubMed1978

Influence of steroids on urea-cycle enzymes in chronic human liver disease.

Activities of Krebs-Henseleit enzymes were determined in liver biopsies of normal persons and in patients suffering from alcoholic hepatitis and chronic active hepatitis. Prednisone was administered for five days in falling dosis (1.5 mg-0.5 mg/kg/body weight) to patients with alcoholic hepatitis and to controls. Patients with chronic active hepatitis received 15-20 mg prednisone daily for more than three months. In healthy persons prednisone did not influence the activities of Krebs-Henseleit enzymes. In patients with alcoholic hepatitis most of the urea-cycle enzymes are significantly decreased (p is less than 0.05) when compared to controls. After glucocorticoid administration enzyme activities remained unchanged. Activities of most of the urea-cycle enzymes are significantly (p is less than 0.05) decreased in untreated patients with chronic active hepatitis. In some of these patients, glucocorticoid administration was associated with a remission as proved by clinical, biochemical and histological data. Activities of the rate-limiting enzymes of the urea-cycle (ASAS, CPS) increased significantly in these patients. By contrast, alterations of enzyme activities could not be observed in patients who failed to respond favourably to steroid treatment.

Arginase↗
PubMed1978

[Hepatitis].

Explore the source record for details and available documents.

Hepatitis↗