[Changes in the sialomucin content of cells of the Yoshida ascites hepatoma after radiotherapy. Cytophotometric analysis]

The X-ray (400 R) action on the membrane glycoproteins, glycolipids and sialic acid residues was studied in Yoshida ascites tumour cells. Some cells were pretreated with neuraminidase and then all were submitted to the Hale's reaction; the stain intensity was determined by integrating microdensitometer at a wave length of 660 nm. A significant decrease of the Hale-positivity (P less than 0,05) has been observed in cells submitted either to radiation or to enzyme treatment.

Effects of isoprenaline treatment on the rat liver parenchyma. Ultrastructural investigations

Ultrastructural modifications of liver cells were studied in adult rats treated with high doses of isoprenaline for 8 days and subsequently sacrificed at various times up to 25 days from the beginning of treatment. The most evident changes were observed at the earliest times after the end of treatment. They involved both the nucleus (changes in shape and chromatin organization) and cytoplasmic organelles such as the rough endoplasmic reticulum and the smooth endoplasmic reticulum, the latter exhibiting marked dilation and increase, while glycogen generally appeared to be decreased. At later times after the end of treatment, these changes tended to disappear, while there was an increase of peroxisomes and particularly of lysosomes, which exhibited a clearly polymorphic pattern.

Ultrastructural cytochemical investigations on adenyl cyclase activity in isoprenaline-treated rat liver

The possibility to demonstrate with cytochemical methods (REIK et al. 1970, HOWELL and WHITFIELD 1972) the activity of adenyl cyclase in rat liver following isoprenaline (IPR) stimulation was evaluated. The drug proved effective as an activator of the enzyme, particularly after in vivo treatment for several days, since it led to the formation of many precipitates which could be ascribed to adenyl cyclase activity, mainly on hepatocyte plasma membranes facing sinusoidal areas. The findings obtained during the experiment, through consistent with the hypothesis of a stimulation of hepatic adenyl cyclase by IPR, pointed out some limitations of the cytochemical techniques now available.

Glycogen changes in the liver cells of young rats following isoprenaline treatment. (Histochemical and ultrastructural investigations)

Glycogen changes were investigated by light and electron microscopy in the liver cells of newborn rats following isoprenaline (IPR) treatment either for 1 day (2 intraperitoneal injections at 12 h interval), or for 8 days (2 intraperitoneal injections daily). On the day following the interruption of both treatments glycogen depletion was observed as compared to control rats, as evaluated by PAS reaction and confirmed by higher total phosphorylase activity. During this stage electron microscopy revealed mainly alpha-particles of glycogen associated to highly dilated smooth endoplasmic reticulum (SER) after 1-day-treatment, and to mostly increased SER after prolonged treatment. In the animals submitted to prolonged IPR administration and sacrificed at later times, glycogen masses intensely PAS-positive were strongly increased, while the activity of total phosphorylase proved accordingly lower than in the rats sacrificed at earlier times. Electron microscopy examination confirmed an increased amount of glycogen (alpha- and beta-particles) differently distributed: beta-particles were more numerous in the liver of the rats sacrificed on the last day of the experiment. At this time SER didn't appear modified as compared to control rats.

Changes in liver cells ploidy of young rats following isoprenaline treatment

Cell proliferation induced by isoprenaline (IPR) stimulation in very high doses was assayed in the liver of young rats, and the formation of polyploid cells was studied form the 15th to the 70th day of life. A general stimulatory effect on a complex process of cellular multiplication, leading to a population of tetraploid cells, was found to be accelerated; the earlier appearance of binucleate cells and the subsequent significant variations in their incidence confirmed the role of this cell type as an intermediate step in the process of polyploidization. Evidence was found of concomitant size changes of the hepatocytes, which might be partially independent of the effect of DNA content. The stimulation was no longer evident 20--30 days from the end of treatment, by when the cells which had come into contact with IPR should have completed the whole sequence of events leading to the formation of tetraploid mononucleate cells.