Biomedical subjects

F Marx

Publications and source records attributed to F Marx.

At least 55 records · Page 3Linked to original sources

PubMed1987

Diurnal variation in glycogen phosphorylase activity in rat liver. A quantitative histochemical study.

The diurnal variations of the glycogen content and of glycogen phosphorylase activity in periportal and pericentral areas of rat liver parenchyma have been analyzed in periodic acid Schiff (PAS)-stained cryostat sections using quantitative microdensitometry. Glycogen content and phosphorylase activity were always higher in periportal areas than in pericentral areas throughout the daily cycle. The glycogen content was highest at the end of the active period during darkness and lowest at the end of the resting period. Phosphorylase activity appeared to be inversely correlated with the glycogen content in both areas. It is concluded that the glycogen content is regulated by phosphorylase activity, which may be due to local cAMP concentration.

Animals↗

PubMed1986

A histochemical study of changes in mitochondrial enzyme activities of rat liver after ischemia in vitro.

Changes in the activity of three mitochondrial enzymes in rat liver after in vitro ischemia have been determined by enzyme histochemical methods. The changes were correlated with the appearance in the electron microscope of flocculent densities in the mitochondria indicative of irreversible cell injury. The flocculent densities were observed in rat liver after about 2 h of ischemia in vitro at 37 degrees C. At the same time the activity of glutamate dehydrogenase, localized in the mitochondrial matrix, started to decrease. However, the activities of succinate dehydrogenase localized in the inner membrane of mitochondria, as well as monoamine oxidase of the mitochondrial outer membrane did not change at that stage. It is concluded from the results of this study and those of others that flocculent densities are formed by denaturation of proteins of the mitochondrial matrix in which glutamate dehydrogenase takes part. It should be considered more as a sign than as the cause of cell death.

Animals↗

PubMed1985

Quantitative aspects of the histochemical tetrazolium salt reaction on monoamine oxidase activity in rat liver.

The tetrazolium method for the histochemical detection of monoamine oxidase (MAO) activity in rat liver cryostat sections has been tested for its specificity and its possible use in quantification. The tetrazolium salt tetranitro blue tetrazolium is recommended for the localization of MAO activity, rather than nitro blue tetrazolium or BPST [2-(2-benzothiazolyl)-3-(4-phthalhydrazidyl)-5-styryl-tetrazolium] . Hardly any formazan was produced in the absence of the substrate tryptamine and Marsilid, a specific inhibitor of MAO activity, prevented formazan production almost completely. A linear relationship between the integrated absorbance measured with a microdensitometer and either the incubation period or section thickness was obtained. We conclude that the method described in this paper can be used for the quantitative analysis of MAO activity in tissue sections of rat liver. MAO activity was found to be 20-25% higher in the periportal zone of rat liver than in the perivenous zone.

Animals↗

PubMed1985

Influence of nutritional state on ischemic damage in rat liver.

The influence of the nutritional state of rats on the volume of necrosis in the liver at 24 h after 60 min ischemia has been estimated using fresh liver slices incubated in tetranitro BT. The volume of necrosis is about 30% in an animal fed ad libitum and about 10% in rats fasted for 24 h. Standardization of the time of feeding using a food dispensing apparatus did not reduce the relatively high individual variation in the extent of liver cell necrosis after ischemia. The beneficial effect of fasting on the extent of liver cell necrosis induced by ischemia may be due to decreased acidosis and/or a change in metabolic status.

Animals↗

PubMed1979