[Late effects of irradiation on the cerebral cortex ultrastructure of the rat].

The glial population balance is significantly disturbed by low dose X-rays even after a very short time following irradiation. The effects are able to persist for a large period of time and may possibly be involved in the onset of late radionecrosis phenomena, often noted as consequences of therapeutic irradiation in brain.

[Development of equilibrium of glial populations in the cerebral cortex of lead intoxicated rats].

The three types of glial cells (astrocytes, oligodendrocytes and microglia) were counted at 2 different ages in normal and lead intoxicated animals (on a 0.5% Pb2+ diet) and were found to vary differently with respect to age and lead treatment. Satellisation of nerve cells by glia also displays a different pattern : whereas usually at 3 month age, the neurons are surrounded by oligodendrocytes, they appear more often encapsulated by microglia after lead treatment.

Hypervascularization of the cerebral cortex in lead-induced encephalopathy.

Pregnant rats were fed a diet containing 1.8% lead acetate for 8 days before delivery until the young were 3 month old. The density of the cerebral cortex capillaries of the infant rats and their convolution rate were studied morphometrically and noted to increase significantly according to the duration of lead treatment, as demonstrated by two-way analysis of variance.