Effect of cerebellar granule cell depletion on spatial learning and memory and in an avoidance conditioning task: studies in postnatally X-irradiated rats.

Rats of the DA/HAN strain (pigmented rats) were submitted to two experimental tasks consisting in spatial learning (water escape experiment) and in passive avoidance conditioning. These rats were either totally or partially deprived of their granule cells using two different schedules of postnatal X-irradiation of the cerebellum. When they were 3 months old, the animals were submitted to an initial learning session, followed by a retrieval test seven days later.

Quantitative analysis of the Purkinje cell and the granule cell populations in the cerebellum of nude mice.

In the nude mutant, a well-known model of athymia in mouse, abnormalities have been reported in the cerebellum, including a 45% reduction in cerebellar size and neuronal loss (Henderson et al., 1981). The present work was aimed at reappraising the claimed anomalies by using quantitative cytological techniques.

Peripheral macrophage abnormalities in mutant mice with spinocerebellar degeneration.

We recently reported hyperproduction of interleukin-1 (IL1) and hyperexpression of IL1 beta mRNA, after in vitro activation by lipopolysaccharide (LPS) in peripheral macrophages of several neurological mutant mice, i.e. staggerer, lurcher, pcd and reeler, that exhibit patterns of neuronal degeneration in the cerebellum; in the present study, we investigated the expression of several cytokine mRNA in peripheral macrophages of other mutants with neuronal degeneration in the cerebellum or in the spinal cord to determine whether this genetic dysregulation is specific for IL1 beta or whether it reflects a generalized hyperexcitability of these macrophages.

Quantitative analysis of the Purkinje cell population during extreme ageing in the cerebellum of the Wistar/Louvain rat.

The loss of neurons is viewed as one of several causes of the deterioration of neural function during ageing. However, the existing experimental evidence for an age-related decrease in the neuronal number may be misinterpreted due to the way the cells are counted and to the interference of unsuspected degenerative pathology of the animals studied. To reinvestigate this question we have quantified an easily identifiable population of neurons, the cerebellar Purkinje cells, in very old but healthy rats.

The ocular dose of ultraviolet radiation to outdoor workers.

Ocular ultraviolet radiation (UVR) exposure was assessed in three occupational groups: fisherman, landscape workers and construction workers. The ratio of ocular exposure to ambient exposure was determined by placing UV-sensitive film (295-320 nm) between the eyes of the subjects and in a nearby open field. The mean ocular exposures varied between 2 and 17% of the ambient exposure on a horizontal surface, depending on whether subjects wore hats, the job performed and the time of year.