Experimental evaluation of rigor mortis. I. Histochemical analysis of rat skeletal muscle in the early post-mortem period.

Histochemical investigation of rat skeletal muscle samples removed immediately post mortem from exercised rats gave the following results: (1) Of the oxidoreductase enzymes studied, there was a slight increase in the activity of cytochrome oxidase. (2) There was no change in the acid- and alkali-stable actomyosin ATPase activity. (3) There was a notable decrease in glycogen concentration. In the case of strychnine intoxication: (1) There was no change in oxidoreductase enzymes. (2) There was an increase in the activity of alkali-stable ATPase in white fibres. (3) The glycogen concentration notably decreased. There was no change in the activity of enzymes studied in those animals sacrificed by anoxia.

[Circadian changes of various enzyme activities in the kidney macula densa of gerbils (Meriones unguiculati)]. / Zirkadiane Veränderungen einiger Enzymaktivitäten in der Macula densa der Nieren von Wüstenratten (Meriones unguiculati).

Circadian Changes of the Activity of some Enzymes in the Macula densa of the Kidney of Mongolian Gerbilis.--The authors investigated the enzyme histochemical activity of some dehydrogenases in the macula densa of desert rodents killed respectively at 11 a.m. and at 11 p.m. The percentage of macula cells which, in comparison with the non specific distal convolution epithelial cells, showed the same or even enhanced enzyme activities was higher at 11 p. m., i.e. nightly (see Tab. 1).

Comparison of the activities of some dehydrogenases in the juxtaglomerular complex of kidneys of Wistar rats and desert rats (Meriones unguiculati).

The authors compared the enzyme histochemical activities of some dehydrogenases in the macula densa, the Goormaghtigh cells and the epithelioid (or juxtaglomerular cells in the kidneys of desert rodents (Mongolian Gerbils) with those of the Wistar rats. The macula cells (Table 1), which in the Wistar rats are clearly distinct from the non specific epithelial cells of the distal convolution, show, in the desert rats, noticeable fluctuations. Their enzyme histochemical reactions are often weaker than those of the distal convolution cells, with the exception of the NAD-tetrazolium-reductase activity. The Goormaghtigh cells (Table 2) in the kidneys of the Meriones have a much larger enzymatic spectrum than in the Wistar rats. Here also, we find functional variations in the examined desert species. In the epithelioid cells (Table 3) we observed a somewhat weaker enzymatic activity in the Meriones. These cells contain no secretion granules, this making their diagnosis difficult.

[Studies of the activity of various dehydrogenases in the desert rat (Meriones unguiculati) nephrons]. / Untersuchungen über die Aktivität einiger Dehydrogenasen in den Nephronen von Wüstenratten (Meriones unguiculati).

Researches about the Activity of some Dehydrogenases in the Nephrons of Desert Rats (Meriones unguiculati).--Our desert rats Meriones unguiculati (Mongolian Gerbils) show--also when held under the same experimental conditions as our other laboratory rodents (Wistar rats and white mice)--a somewhat different enzyme histchemical behaviour of these nephrons. The essential difference in the Meriones is that their distal convolutions display on the whole stronger enzyme activities compared as well with the proximal convolutions of the same kidneys, as with the distal convolutions of Wistar rats.

[Enzyme histochemical studies on the macula and Goormaghtigh cells of the guinea pig kidney]. / Enzymhistochemische Untersuchungen an den Macula- und Goormaghtigh-Zellen der Meerschweinchen-Niere

Starting from the ultrastructural differences observed between the juxtaglomerular apparatus of the rat and that--only very rarely analysed--of the guinea pig kidney, the authors supposed that enzymhistochemical differences might also exist. This hypothesis could be confirmed by the results obtained in the Macula densa- and the Goormaghtigh-cells (Tab. 1 and 2). Indeed, in both places the Isocitrate dehydrogenase- and the Malate dehydrogenase-activities are stronger in the guinea pig than in the rat. On the other hand, the Glucose-6-phosphate and the 6-Phosphogluconate dehydrogenases show clearly weaker activities in the guinea pig Macula-cells compared with those of the rat, where these two enzymes give by far the strongest reaction. Metabolic differences might be related to the described diversities of the enzyme equipment.