Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fever has had a long phylogenetic history: it occurs not only in infected birds and mammals, but also in infected reptiles, amphibians, fish and even insects. When these "cold-blooded" animals are prevented from adapting their body temperature to the risen thermoregulatory set-point by behavioral means, a more severe state of disease and a higher mortality are the consequences. It seems unlikely that an energy-dependent process, such as fever, would have been retained for hundreds of millions of years, in so many groups of organisms, if it provided no selective advantage. Fever may represent a leukocyte-based amplification mechanism to affect host challenge: enhanced motility of leukocytes, enhanced lymphocyte response to mitogens, increased production of interferon, enhanced immune response to viral antigens. Evidence for a beneficial effect of fever is also supported by the results of our animal experiments. Intraperitoneal injection of a high dose of bacterial lipopolysaccharide (LPS) in rats induces a septic shock like state which is accompanied by hypothermia on the day of LPS-administration and a robust fever on the following days. Co-injection of a neutralizing synthetic form of the soluble tumor necrosis factor (TNF) type 1 receptor completely neutralizes LPS-induced bioactive TNF in the lavage of the abdominal cavity and in blood plasma. Treatment with the TNF-antagonist results in much faster recovery from the hypothermic state. The rats develop pronounced fever already on the day of injection and there is significantly less reduction in body weight and food and water intake. Similar, but less pronounced effects can be induced by treatment with inhibitors of the inducible form of nitric oxide (NO)-synthase indicating that TNF-induced detrimental effects are, in part, mediated by excessive formation of NO. These results confirm that an accelerated onset of fever or a faster recovery from hypothermia in a septic state may have rather beneficial than maladaptive effects.
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PMID:[Fever in acute illness: beneficial or harmful?]. 1206 Sep 73

Fever is a coordinated autonomic, endocrine, and behavioral response mediated by the brain in reaction to inflammatory stimuli. An essential step in transmitting the immune signal to the brain is the formation of prostaglandin E2. Cyclooxygenase (COX) is the critical enzyme in the synthesis of prostaglandins and COX-2, the inducible form of the enzyme, is markedly induced in cells associated with the cerebral blood vessels and the leptomeninges by immune stimuli such as intravenous administration of lipopolysaccharide (LPS). However, the specific roles of COX-1, the constitutive form of cyclooxygenase, and COX-2 in LPS-induced fever are not well understood. We injected LPS i.v. in combination with either a highly selective COX-1 (SC-560) or COX-2 (SC-236) inhibitor to determine the effects of each drug on the subsequent fever response and on the pattern of expression of Fos protein in the brain. The COX-2 inhibitor blocked LPS-induced fever and Fos expression in sites such as the ventromedial preoptic nucleus (VMPO) and the hypothalamic paraventricular nucleus (PVH), although Fos-immunoreactivity in the nucleus of the solitary tract (NTS), ventrolateral medulla (VLM), and parabrachial nucleus (PB) remained. In contrast, the COX-1 inhibitor resulted in a profound hypothermic response to LPS and blocked LPS-induced Fos-immunoreactivity in the PVH, PB, NTS, and VLM, although it had no effect on the VMPO. Although COX-2 plays a dominant role in mediating fever responses to i.v. LPS, at least some components of the response, including avoiding hypothermia and the induction of Fos in the NTS, VLM, PB, and PVH, appear to depend on COX-1. J.
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PMID:Specific roles of cyclooxygenase-1 and cyclooxygenase-2 in lipopolysaccharide-induced fever and Fos expression in rat brain. 1281 98

Heat shock protein 70 (Hsp70) is induced in cells by a variety of stress conditions, is known to be cytoprotective, and has been proposed to be neuroprotective during brain ischemia. A recently developed mouse model of 12-min global cerebral ischemia by bilateral common carotid artery occlusion with artificial ventilation and bilateral monitoring of regional cerebral blood flow by laser Doppler was applied. We examined the expression and possible neuroprotective role of the inducible form of Hsp70 in the mouse brain following global cerebral ischemia. Ischemia induced a marked expression of Hsp70 in the ischemia vulnerable CA1-CA3 region of the hippocampus. Intraischemic hypothermia (33 degrees C) prevented cell damage without noticeable expression of Hsp70. A transgenic mouse overexpressing Hsp70 was subjected to 12 min of global cerebral ischemia, and the brain damage was evaluated after 4 days. No neuroprotection of ischemia-induced brain damage in hippocampus, striatum, cortex or thalamus was found in Hsp70 transgenic animals compared with wild-type littermate mice. We suggest that overexpression of Hsp70 following cerebral ischemia is an indicator of cell stress. Also, constitutively overexpression of Hsp70 is insufficient to effectively influence cell death after global cerebral ischemia in the mouse.
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PMID:Lack of neuroprotection by heat shock protein 70 overexpression in a mouse model of global cerebral ischemia. 1457 3

Traumatic injury to the brain and spinal cord results in an early inflammatory response that is initiated by the release of proinflammatory cytokines followed by the infiltration and accumulation of polymorphonuclear leukocytes (PMNLs). The role of the inflammatory cascade on traumatic outcome remains controversial. Pleiotropic cytokines appear to function both protectively and destructively. The induction of cytokines can lead to the expression of the inducible form of nitric oxide synthase (iNOS), which in turn provokes the release of excessive amounts of nitric oxide (NO) that may participate in the pathogenesis of tissue injury. Hypothermia has been reported by various groups to be neuroprotective in brain and spinal cord trauma. We studied the effect of therapeutic hypothermia on cerebral IL-1beta concentrations, PMNL accumulation and iNOS activity after traumatic brain injury (TBI) and spinal cord injury (SCI). Based on current data therapeutic hypothermia may protect in models of traumatic injury by modulating deleterious inflammatory processes.
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PMID:The role of inflammatory processes in the pathophysiology and treatment of brain and spinal cord trauma. 1533 3

We have demonstrated that therapeutic administration of L-arginine (L-arg) (120 mg/kg) at +2 h of whole body hyperthermia (WBH) could rescue the mice from heatstroke-induced death. Studies were undertaken to elucidate the role of L-arg in the immunomodulation of the heat-stressed mice. Administration of L-arginine (L-arg), (120 mg/kg, i.p.), at +2 h of WBH, rescued the mice from heat-induced death and reduced the hypothermia. At +4 and +24 h of WBH, levels of IL-1beta, IFN-gamma, nitrite, TNF-alpha, IL-4, TGF-beta1, inducible form of nitric oxide synthase (iNOS), and corticosterone significantly increased compared to the sham group. The elevated levels of Th(1) cytokines, namely TNF-alpha, IL-1beta, IFN-gamma, nitrite, and iNOS, decreased significantly both at +4 and +24 h of WBH, following L-arg administration. However, L-arg administration did not reduce the increased levels of Th(2) cytokines, namely IL-4 and TGF-beta1, in WBH mice at +4 h of WBH. L-arg administration significantly increased the levels of Th(2) cytokines at +24 h of WBH, compared to the saline-treated WBH mice. L-arg administration significantly increased both the splenic and hepatic arginase activity at +4 and +24 h of WBH compared to the saline-treated WBH mice. L-NAME treatment at +2 h of WBH and anti-TGF-beta antibody treatment at 0 h of WBH significantly increased the mortality compared to the saline-treated WBH mice. Altered liver histopathology was attenuated following the administration of L-arg at +2 h of WBH. These results suggest that therapeutic administration of L-arg at appropriate concentration and time attenuates the acute inflammatory response, leading to the rescue of mice from heatstroke.
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PMID:Arginine metabolic pathways determine its therapeutic benefit in experimental heatstroke: role of Th1/Th2 cytokine balance. 1676 19