Development and neuronal dependence of cutaneous sensory nerve formations: Lessons from neurotrophins.

Null mutations of genes from the NGF family of NTs and their receptors (NTRs) lead to loss/reduction of specific neurons in sensory ganglia; conversely, cutaneous overexpression of NTs results in skin hyperinnervation and increase or no changes in the number of sensory neurons innervating the skin. These neuronal changes are paralleled with loss of specific types of sensory nerve formations in the skin. Therefore, mice carrying mutations in NT or NTR genes represent an ideal model to identify the neuronal dependence of each type of cutaneous sensory nerve ending from a concrete subtype of sensory neuron, since the development, maintenance, and structural integrity of sensory nerve formations depend upon sensory neurons.

The Meissner and Pacinian sensory corpuscles revisited new data from the last decade.

This article reviews the biochemical, physiological, and experimental data cumulated during the last decade on the Meissner and Pacinian corpuscles. It includes information about (i) the localization of molecules recently detected in sensory corpuscles; (ii) the unsolved problem of the accessory fibers in sensory corpuscles and the occurrence of myelin within them; (iii) the development of sensory corpuscles, especially their neuronal and growth factor dependency; (iv) the composition and functional significance of the extracellular matrix as an essential part of the mechanisms involved in the genesis of the stimuli generated in sensory corpuscles; (v) the molecular basis of mechanotransduction; (vi) a miscellaneous section containing sparse new data on the protein composition of sensory corpuscles, as well as in the proteins involved in live-death cell decisions; (vii) the changes in sensory corpuscles as a consequence of aging, the central, or peripheral nervous system injury; and finally, (viii) the special interest of Meissner corpuscles and Pacinian corpuscles for pathologists for the diagnosis of some peripheral neuropathies and neurodegenerative diseases.

Acute mountain sickness: influence of fluid intake.

Objective: High altitude and exposure to cold are associated with significant levels of dehydration because of cold-altitude urine output, high energy expenditures, and poor access to water. The aims of the present study were to measure the fluid intake and urine output among military mountaineers during their stay at high altitude and to study the level of fluid intake and decrease in urine output in relation with acute mountain sickness (AMS).

Methods: This study used an analytic prospective follow-up design of hydration-dehydration conditions of a group of mountaineers with similar characteristics (military group).