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Biomedical subjects

R Kramar

Publications and source records attributed to R Kramar.

At least 73 records · Page 4Linked to original sources

An experimental study of acute and chronic effects of phenacetin on the rat kidney, using clinical-chemical and biochemical methods.

In rats, changes in urinary enzymatic activities (AP, SP, LAP, beta-GLU, MUR) were recorded following the administration of phenacetin in acute doses (4.75 and 7.15 mmol/kg). Urinary AP and LAP activities were measured over 77 days in which 3.35 mmol phenacetin/kg were given daily. The results revealed immediate and delayed effects of phenacetin, depending upon the quality of the drug used. In the chronic series, changes in urinary enzymatic activities were less pronounced. Concomitant biochemical investigations of kidney cell fractions revealed the occurrence of mitochondrial damage under the influence of chronic phenacetin administration. Following acute doses of phenacetin, destructive alterations in the plasma membrane of kidney cells were encountered. Investigations of serum enzymatic activities 24 h after phenacetin administration did not reveal any significant changes.

Alkaline Phosphatase↗

Phenacetin and the liver. The influence of phenacetin in acute and chronic doses on membrane-bound mitochondrial enzymes in the rat.

Following the administration of phenacetin in single and in multiple high doses, enzymes bound to the inner mitochondrial membrane of the liver were determined. Acute doses of phenacetin (75% of oral LD50) failed to produce any effect. The chronic administration of phenacetin provoked a small but statistically significant decrease in the TD-trnashydrogenase activity. This observation indicates that liver damage may occur in patients with phenacetin abuse.

Animals↗

Influence of subtotal hepatectomy on peroxisomes and peroxisomal enzymes of rat liver and isolated liver cell fractions.

The activities of peroxisomal enzymes of rat liver were followed 1 to 10 days after subtotal (60-70%) hepatectomy in homogenates prepared from regenerating livers and in cell fractions isolated from them. Catalase activity was found to be depressed in the total liver homogenate (H) as well as in the mitochondrial (M) and soluble (S) fractions, while it did not change appreciably in the microsomal (Mc) and lysosomal (L) fractions. Alpha-hydroxyacid oxidase behaved in a similar fashion. In contrast to these enzymes, urate oxidase activity remained unchanged in H, whereas it was decreased in M and increased in L and Mc during the first 5 days after operation. These results agree well with the assumption that microbody proliferation is initiated by the fragmentation of large peroxisomes. The different relations of peroxisomal enzyme activities during regeneration time are discussed with respect to the possible existence of various kinds of peroxisomes with different enzyme equipments and with different turnover rates. Biochemical examinations ions were paralleled to morphological and histochemical studies. An early increase in number of peroxisomes was found to occur during the first day after partial hepatectomy, which is accompanied by decrease in particle size. During the first mitotic wave (24-36 hrs post op.) the number of peroxisomes per cell was reduced to about the half. After this time number and size of the particles began to increase. Positive staining of ribosomes was frequently observed in the vicinity of peroxisomes after the application of the cytochemical catalase reaction (alkaline diaminobenzidine medium). This phenomenon is interpreted to represent rather a diffusion artifact than the cytochemical identification of newly synthesized catalase.

Alcohol Oxidoreductases↗