Impaired sweating responses to a passive whole body heat stress in individuals with multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS), disrupting autonomic function. The aim of this study was to test the hypothesis that individuals with MS have blunted control of thermoregulatory reflex increases in sweat rate (SR) and cutaneous vasodilation compared with controls during a passive whole body heat stress (WBH). Eighteen individuals with relapsing-remitting MS and 18 healthy controls (Con) participated in the study. Core temperature (Tcore), skin temperature, heart rate, arterial blood pressure (10-min intervals), skin blood flow (laser-Doppler flux, LDF), and SR were continuously measured during normothermic baseline (34°C water perfusing a tube-lined suit) and WBH (increased Tcore 0.8°C via 48°C water perfusing the suit). Following WBH, local heaters were warmed to 42°C, inducing peak cutaneous vasodilation at the site of LDF collection. Cutaneous vascular conductance (CVC) was calculated as the ratio of LDF to mean arterial pressure and expressed as a percentage of peak achieved during local heating. Individuals with MS had attenuated SR responses to WBH (ΔSR from baseline: Con, 0.65 ± 0.27; MS, 0.42 ± 0.17 mg·cm-2·min-1, P = 0.003), whereas Δ%CVC42C from baseline was similar between groups (Con, 42 ± 16%; MS, 38 ± 12%, P = 0.39). SR responses were blunted as a function of Tcore in MS (interaction: group × Tcore, P = 0.03), of which differences were evident at ΔTcore 0.7°C and 0.8°C (P < 0.05). No interaction was observed in Δ%CVC42C Taken together, the findings show MS blunts sweating responses, whereas control of the cutaneous vasculature is preserved, in response to WBH.NEW & NOTEWORTHY This study is the first to assess the reflex control of the thermoregulatory system in individuals living with multiple sclerosis (MS). The novel findings are twofold. First, attenuated increases in sweat rate in subjects with MS compared with healthy controls were observed in response to a moderate increase (0.8°C) in core temperature via passive whole body heat stress. Second, it appears the reflex control of the cutaneous vasculature is preserved in MS.

PCR Testing of Filter Material from IVC Lids for Microbial Monitoring of Mouse Colonies.

Testing sentinel animals exposed to soiled bedding from colony animals is the most common method used for health monitoring in rodent facilities. Although environmental sampling is being explored-and, in many cases, has been implemented-as an alternative, exhaust plenum sampling is not effective for all ventilated rack designs. This study evaluated PCR testing of filter paper from sentinel cages on ventilated racks. We hypothesized that testing filter paper from cages containing soiled bedding would be as effective as testing sentinel mice and that periodic shaking of cages would generate sufficient particulate movement to substitute for the presence of live animals. Three cages containing soiled bedding were maintained in each of 8 rooms; one cage contained 2 Cr:NIH(S) mice, one had no mice and was shaken twice weekly, and the remaining one had no mice and was left undisturbed. For 3 consecutive months, a piece of filter paper from the undersurface of the cage lid was tested monthly for adventitial agents and then replaced. A second piece remained on the cage undersurface for 3 mo. Fecal pellets and oral and fur swabs were collected from sentinel mice at months 1 and 3 and tested for the same agents. At month 3, serology was performed on the sentinel mice; feces and oral and fur swabs from colony animals were tested concurrently for comparison. Filter paper from cages without mice and shaken were at least as effective than all other methods in detecting the presence of endemic agents, including mouse norovirus, Helicobacter spp., Pasteurella pneumotropica, Entamoeba muris, and Spironucleus muris. For IVC systems where exhaust plenum testing is ineffective, PCR testing of IVC filter tops should be considered as an alternative to soiled bedding sentinels. Environmental sampling may provide increased reliability and reduce the number of rodents used for routine health surveillance.