Search

Embryonic liver cells of chicken have been cultivated in medium more or less supplemented with serum. With a rich medium mitochondria become larger and often ramify. Their fundamental structure remains normal. It is only a hypertrophic condition correlated to an increase of mitochondrial material synthesis, limited to liver mitochondria.

A previous organotypic culture of rat's superior ganglion is propitious to the survey of grafts. Neurons keep their own structure for 15 to 18 months. A methodical study of grafts find rather rare or exceptionally frequent paraganglionary cells. These cells (S.I.F. Cells type) can keep their ultrastructural aspect in superior cervical ganglion graft for 15 months and even more.

The influence of the blood-testis barrier on the synthetic capabilities of male germ cells in the mouse as investigated by quantitative radioautography in aggregates of seminiferous tubules incubated in a modified Rose chamber, in the presence of tritiated leucine. In the seminiferous tubule, a distribution gradient of radioactivity could be seen : radioactivity decreased from the periphery towards the lumen. Labelling intensity was approximately equivalent in type B spermatogonia and pachytene primary spermatocytes but was only one third as heavy in spermatids (steps 4-5). These results which confirm prior observations carried out in both animal and germ cells isolated from the seminiferous epithelium by differential sedimentation velocity indicate that the blood-testis barrier has no significant effect on the capacity for synthesis peculiar to each germ-cell population.

In the complexe system of synapses in the white rat's superior cervical ganglion, authors show the existence of: 1 - somato-somatic neuronal synapses 2 - somatic synapses between S.I.F. cells 3 - recurrent auto-synapses They moreover mention widening of synaptic cleft of the synapses between S.I.F. cells and their processes.

The ultrastructure of the carotid corpuscle has been studied on males Wistar rats, from their birth to eighteen months. In the course of the ageing of the animal, th cytology of the constitutive elements is altered. The size of the main cells is maximal at eleven months. If the Golgi apparatus and the mitochondria do not seem very altered, the granular vesicles, the number of the ribosomes, especially these in contact with the membranes of the granular endoplasmic reticulum diminish. The vacuolisation, increased after the first month, the cells in course of degeneration, and the cellular phantoms observed from the fifth month, reveal the very slow and gradual involution of the corpuscle. The lysosomes appear infrequent as early as their birth and their slow growth in size more significant than the growth in number conjunctively with an important fibrose characterizes the senescent corpuscle. All the corpuscles seem affected in the same way, since the amplitude of alterations do not vary much from one animal to another. So in the corpuscles of every rat over one year, the clear cells prevail, not very altered by the ageing process.

Addition of lithium salts to cultures of hepatocytes increases glycogen in these cells. Glycogenolytic action of glucagone or AMPc becomes slow. Toxic action of paraquat is suppressed.