Biomedical subjects

J Mariani

Publications and source records attributed to J Mariani.

129 records · Page 8Linked to original sources

PubMedDate not supplied

Synapse elimination in the central nervous system: functional significance and cellular mechanisms.

Recent research into the developmental elimination of supernumerary synapses has increased understanding of this process. In this review we discuss synapse elimination both at the neuromuscular junction and in the central nervous system, considering some possible underlying mechanisms suggested by recent studies. In addition a well-described example of central nervous system synapse elimination, the climbing fiber-Purkinje cell synapse of the cerebellum, is used to explore the functional significance of synaptic regression during brain development.

Animals↗

PubMedDate not supplied

Differential IL-6 mRNA expression by stimulated peripheral macrophages of Staggerer and Lurcher cerebellar mutant mice.

We have recently reported about a hyperexpression of interleukin-1 mRNA by stimulated peripheral macrophages of several cerebellar mutant mice exhibiting complex patterns of neuronal degeneration in the cerebellum. Interestingly, studying the staggerer mutant mice, our data showed a hyperexpression of IL-1 beta mRNA and a hyperproduction of the cytokine. The hyperexpression of IL-1 beta mRNA was observed whatever the conditions of stimulation and the stimulating agent used, a hyperexpression of IL-1 alpha and TNF alpha mRNAs was also detected. This set of data suggests a hyperexcitability state of (sg/sg) macrophages. In the present study, we examined the IL-6 mRNA expression by stimulated peripheral macrophages of two cerebellar mutant mice, the staggerer and the lurcher mutants. Our results show that IL-6 mRNA is hyperexpressed in stimulated macrophages of staggerer mutant mice. On the contrary, no hyperexpression is observed in stimulated macrophages of lurcher mutant mice. These results suggest that the neuronal degeneration affecting the cerebellum in the two mutant mice do not lead to the same immunological defect at the peripheral level.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMedDate not supplied

IL-1 and LPS induce a sexually dimorphic response of the hypothalamo-pituitary-adrenal axis in several mouse strains.

Sexual steroids are involved in the regulation of the immune system and modulate directly the synthesis of interleukin-1 (IL-1) by macrophages. Bacterial lipopolysaccharides (LPS) and IL-1 stimulate the hypothalamo-pituitary-adrenal (HPA) axis. As a result, glucocorticoids initiate a negative feedback loop since they inhibit the synthesis of IL-1. In this study we wanted to estimate the respective effects of genetic background, gender and sex-hormones (as assessed by gonadectomy) upon the HPA axis response to either IL-1 or LPS of mice of both sexes in 3 different strains: B6, CBA and B6 x CBA. Plasma ACTH and corticosterone, the predominant glucocorticoid in rodent, were determined by radioimmunoassay. IL-1 alpha or beta, 10 ng (per g. body weight), were injected i.p. and mice bled 2 h later. In the 3 strains, Il-1 alpha induced ACTH and IL-1 alpha and beta induced corticosterone responses, nearly 2-fold higher in females than in males. In the 3 strains, ovariectomy, as compared to sham operation, lowered the corticosterone values, while orchidectomy had no effect. LPS, 1.25 micrograms (per g. body weight), was injected i.p. and mice bled 2, 4 or 6 h later. The kinetics of the corticosterone response was sex- and strain-dependent. After 4 h, females of each strain had higher levels than males. Gonadectomy, as compared to sham operation, lowered the response of both males and females in the B6 strain, but was unefficient in the CBA one.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗