Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypothermia is not and should not be a prevalent feature of diving, yet many divers become extremely cold and uncomfortable during their work. It is not difficult to provide adequate insulation to protect the torso but if movement and dexterity are to be maintained, the extremities will inevitably suffer. Free swimming divers are limited by duration in cold (5 degrees C), shallow (10 m) water. Six hours is a typical maximum before both core cooling and extremity pain or dysfunction pose a threat. Habituation to cold may be observed in some divers. Surface supplied or bell supported divers, relying on supplementary hot water, need between 500 and 3500 Watts to preserve comfort over the range 10 to 300 m depth. Deep diving, using oxyhelium gas mixtures, can result in high respiratory convective losses in excess of 300 Watts. Heat exchangers are used to prevent damage to the tract. There have been a number of cases where hypothermia has been implicated in the cause of death in diving accidents, but generally the reason is not lack of physiological knowledge but equipment failure and inadequate contingency. Recent developments in diver protection have focused on electrically heated hand wear to preserve performance and prevent the risk of non freezing injury in a relatively inactive diver.
 ...
PMID:Diving and hypothermia. 181 77

Integrated electromyographic, electrocortical (ECoG) and electro-ocular activity were recorded in 13 chronically prepared fetal sheep (130-145 days). Fetal movements and the rate of habituation to repeated suffusions of cold saline against the fetal skin were recorded. Experiments were repeated during an intravenous infusion of noradrenaline to the fetus (0.4 microgram/kg estimated fetal weight/min) and during hypoxia induced by altering the oxygen content of the inspired air to the ewe to 9%. Repeated stimulation with cold saline resulted in an increase in fetal movements (p = 0.009). The number of stimuli for habituation was similar in high-voltage and in low-voltage ECoG activity. The rate of fetal habituation was significantly faster during the infusion of noradrenaline compared with control measurements (p = 0.009). During hypoxia, the number of spontaneous fetal movements prior to stimulation decreased (p = 0.002). Habituation rates were also faster during hypoxemia compared with control measurements (p = 0.003). These findings may help to explain the rapid habituation rates seen in some human fetuses in at 'at risk' pregnancies.
 ...
PMID:Effect of hypoxia and catecholamines on the habituation rates of chronically catheterized ovine fetuses. 280 86

Cutaneous circulation increases greatly in sauna in order to prevent body heating. Blood pressure tends to fall but this is prevented by increased cardiac output by means of faster heart rate and by decreased blood flow to the visceral organs. Cooling in cold air, shower, water or rolling in snow causes rapid cutaneous vasoconstriction, which leads to elevation of arterial blood pressure and increase of central venous blood volume. The effects of both heat and cold are mediated via the sympathetic nervous system. The circulatory responses to sauna are related to the intensity and duration of the heat exposure. An ordinary sauna bath increases cardiac workload about as much as moderate or vigorous walking. Habituation to sauna decreases the sympathetic stimulation and cardiovascular responses. Sudden cooling, for example diving in cold water, causes a severe transitory volume load and pressure load to the heart and increases the possibility of cardiac arrhythmias. The risk of cardiovascular complications in correctly practiced sauna bathing is very small and it is confined to subjects predisposed to the risk because of manifest or latent cardiovascular abnormalities.
 ...
PMID:Sauna bather's circulation. 321 96

1. Male and female Scottish Blackface sheep were shorn and exposed for 2 weeks either to a thermoneutral temperature (+30 degrees C), to chronic cold (+8 degrees C) or to +30 degrees C interrupted by daily short cold shocks (-10 degrees C). During and at the end of these conditioning treatments, the sheep also received two acute cold exposures (-20 degrees C, 4 m.p.h. wind for 2-8 hr) 1 week apart. Some of these sheep and a fourth (control) group, were subsequently re-shorn and slowly cooled to +8 degrees C.2. Resting metabolism and the metabolic response to cooling (both inferred from heart rates) were increased by previous chronic cold treatment. Resistance to body cooling (measured during acute cold exposure) was generally increased by both chronic and acute cold, and non-shivering thermogenesis was probably induced in the female sheep. These effects were defined as acclimatization.3. In contrast, cold shocks reduced the subsequent metabolic response to cold and encouraged facultative body cooling. This pattern of response (defined as habituation) therefore caused greater thermolability.4. Habituation and acclimatization were antagonistic. Habituation was removed by acute cold exposure and, conversely, acclimatization was inhibited by short cold shocks.5. There were sex differences in response but these were confounded by probable differences in insulation and in body condition (males thinner).6. It was concluded that the induction of different forms of adaptation depended on the length, severity and frequency of cold exposures. Habituation to whole body cold exposure apparently involved central nervous system centres normally receiving peripheral cold stimuli.
 ...
PMID:Habituation and acclimatization of sheep to cold following exposures of varying length and severity. 464 85

The aim of the study was to examine reproducibility of primary and secondary hyperalgesia in a psychophysical model of human inflammatory pain. Mild burns were produced on the crura of 12 volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min). Assessments of (i) cold and warm detection thresholds, (ii) mechanical and heat pain thresholds, (iii) pain to heat (43 degrees C and 45 degrees C, 5 s), (iv) secondary hyperalgesia, and (v) skin erythema were made 1.75 and 0.5 h before, and 0, 1, 2, 4, and 6 h after a burn injury. Sensory thresholds and hyperalgesia to heat and mechanical stimuli were examined by contact thermodes and von Frey hairs, and pain intensity was rated with a visual analog scale (0-100). To describe between-day reproducibility, the subjects were examined three times at intervals of 21 days. Within-day comparisons showed that a 20% change could be detected as significant for all variables with fewer than 12 subjects in a cross-over design (2alpha = 5% and power = 80%). Between-day comparisons demanded up to 25 subjects to detect changes of the same magnitude. The burns caused mild to moderate pain (VAS: mean 29, SD 14) and the subjects (all right-handed) were more sensitive to heat pain on their left side (P < 0.03). Hyperalgesia was induced instantaneously by the burn and outlasted the study period (6 h). However, no spontaneous pain was observed after the injury, and a brief period of hypoesthesia to warm and cold stimuli was induced by the burn. The painful measurements themselves evoked hyperalgesia to heat and mechanical stimuli on the arm, but only to mechanical stimuli on the legs. including secondary hyperalgesia. Hyperalgesia evoked by the measurements was significantly less intense than that induced by injury. Habituation to the painful stimuli was demonstrated by significantly higher pain thresholds and lower pain responses on the second and third day of the study. The burn model is a sensitive psychophysical model of acute inflammatory pain, when cross-over designs and within-day comparisons are used, and the model is suitable for double-blind, placebo-controlled studies of analgesics. In similar models, we recommend that analgesic and placebo are evenly divided between right and left sides and study days.
 ...
PMID:Hyperalgesia in a human model of acute inflammatory pain: a methodological study. 952 Feb 28

The initial responses to cold-water immersion, evoked by stimulation of peripheral cold receptors, include tachycardia, a reflex inspiratory gasp and uncontrollable hyperventilation. When immersed naked, the maximum responses are initiated in water at 10 degrees C, with smaller responses being observed following immersion in water at 15 degrees C. Habituation of the initial responses can be achieved following repeated immersions, but the specificity of this response with regard to water temperature is not known. Thirteen healthy male volunteers were divided into a control (C) group (n = 5) and a habituation (H) group (n = 8). Each subject undertook two 3-min head-out immersions in water at 10 degrees C wearing swimming trunks. These immersions took place at a corresponding time of day with 4 days separating the two immersions. In the intervening period the C group were not exposed to cold water, while the H group undertook another six, 3-min, head-out immersions in water at 15 degrees C. Respiratory rate (fR), inspiratory minute volume (VI) and heart rate (fH) were measured continuously throughout each immersion. Following repeated immersions in water at 15 degrees C, the fR, VI and fH responses of the H group over the first 30 s of immersion were reduced (P < 0.01) from 33.3 breaths x min(-1), 50.5 l x min(-1) and 114 beats x min(-1) respectively, to 19.8 breaths x min(-1) 26.41 x min(-1) and 98 beats x min(-1), respectively. In water at 10 degrees C these responses were reduced (P < 0.01) from 47.3 breaths x min(-1), 67.61 x min(-1) and 128 beats x min(-1) to 24.0 breaths x min(-1), 29.5 l x min(-1) and 109 beats x min(-1), respectively over a corresponding period of immersion. Similar reductions were observed during the last 2.5 min of immersions. The initial responses of the C group were unchanged. It is concluded that habituation of the cold shock response can be achieved by immersion in warmer water than that for which protection is required. This suggests that repeated submaximal stimulation of the cutaneous cold receptors is sufficient to attenuate the responses to more maximal stimulation.
 ...
PMID:Temperature dependence of habituation of the initial responses to cold-water immersion. 972 Oct 5

Emotional stress affects cellular integrity in many tissues including the heart. Much less is known about the effects of social stress. We studied the effect of emotional (immobilization with or without cold exposure) or social (intermale confrontation) stress in mice. Tissue injury was measured by means of the release of enzyme activities to blood plasma: lactate dehydrogenase (LDH), creatine kinase (CK), aspartate transaminase (AST), and alanine transaminase (ALT). Tape-immobilization increased all these activities in the plasma. AST-ALT ratio was also increased in these animals. Electrophoretic analysis of CK isoenzymes showed the appearance of CK-MB. These results indicate that the heart was injured in immobilized mice. Analysis of LDH isoenzymes and measurement of alpha-hydroxybutyrate dehydrogenase (HBDH) activity suggests that other tissues, in addition to the heart, contribute to the increase in plasma LDH activity. Restraint in small cylinders increased plasma LDH, CK, AST, and ALT activities, but to lower levels than in tape immobilization. Because the decrease in liver glycogen and the increase in plasma epidermal growth factor (EGF) were also smaller in restraint than in the tape-immobilization model of emotional stress, we conclude that the former is a less intense stressor than the latter. Cold exposure during the restraint period altered the early responses to stress (it enhanced liver glycogen decrease, but abolished the increase in plasma EGF concentration). Cold exposure during restraint enhanced heart injury, as revealed by the greater increase in CK and AST activities. Intermale confrontation progressively decreased liver glycogen content. Plasma EGF concentration increased (to near 100 nM from a resting value of 0.1 nM) until 60 minutes, and decreased thereafter. Confrontation also affected cellular integrity in some tissues, as indicated by the rise in plasma LDH activity. However, in this type of stress, the heart appeared to be specifically protected because there was no increase in plasma CK activity, and both AST and ALT increased, but the AST-ALT ratio remained constant. Habituation to restraint (1 h/d, 4 days) made mice resistant to restraint-induced tissue injury as indicated by the lack of an increase in plasma LDH, CK, AST, or ALT activities. Similar general protection against homotypic stress-induced injury was observed in mice habituated to intermale confrontation.
 ...
PMID:Acute stress-induced tissue injury in mice: differences between emotional and social stress. 1189 86

We examined the role of the posterior division of the paraventricular nucleus of the thalamus (pPVTh) in habituation of hypothalamic-pituitary-adrenal (HPA) responses to repeated restraint. Habituation refers to the decrement in HPA activity that occurs with repeated exposure to the same or homotypic stressor. To date, the pPVTh has been shown to inhibit the enhanced or facilitated HPA responses to novel, heterotypic restraint in previously chronically cold stressed rats. We hypothesized that the pPVTh also inhibits HPA activity under conditions of habituation. In the first experiment, we lesioned the pPVTh and examined adrenocorticotropic hormone (ACTH) and corticosterone responses to the first or eighth restraint exposure. In sham-lesioned rats, we found lower ACTH and corticosterone responses to the eighth period of 30 min restraint compared to the first exposure, evidence for habituation. In pPVTh-lesioned rats, there was no difference in ACTH and corticosterone responses to the eighth compared to the first restraint exposure. Therefore, pPVTh lesions prevented the habituation of HPA responses to repeated restraint. In the second experiment, we examined whether habituation to restraint is observable in response to an acute, single restraint on day 28 in sham and pPVTh lesioned rats that were exposed to restraint only on days 1 through 8. In this experiment, we replicated the results from the first experiment, and found evidence that habituation to restraint can be observed weeks after chronic stress has been terminated. Furthermore, pPVTh lesions had no additional effects on HPA responses to acute stress on day 28. In summary, pPVTh lesions inhibit habituation of HPA activity to a homotypic stressor, without altering HPA responses to the first restraint. Thus, the intact pPVTh inhibits HPA activity under conditions of habituation, as well as facilitation, and represents an important regulator of HPA activity under conditions of chronic stress.
 ...
PMID:Lesions of the posterior paraventricular thalamus block habituation of hypothalamic-pituitary-adrenal responses to repeated restraint. 1200 May 46

Clinicians claim that patients habituate to cold-induced pain during cryokinetic treatments, but this has not heretofore been tested. We treated the right ankle of 38 subjects with a simulated cryokinetic treatment daily for 8 days using either 1 degrees or 5 degrees C water. On days 9 and 10, the right ankle was treated with the opposite temperature and the opposite ankle (left) was treated with the habituation temperature. Cold-induced pain was recorded five times each day (after each ice immersion bout) using Borg's Perceived Pain Scale and the McGill Pain Questionnaire. There was a sharp decrease in pain from days 1 through 5, but no difference between days 5 through 8. Pain during bout one was significantly greater than the following four bouts for all days except day 1. Location of pain changed between days but not between bouts. The instep was the most frequent location of pain for the first 3 days. The choice of "no specific location" increased steadily from day 2 to 8. The number of descriptor terms chosen on the McGill Pain Questionnaire decreased from day 1 to day 8. Exceptions to this were the terms cool, cold, freezing, and numb. Common terms chosen on days 1 through 3 were throbbing, sharp, burning, tingling, hurting, and nagging. On days 9 and 10, pain in the opposite (left) limb was greater than pain at the end of right limb habituation, but similar to day 1 of habituation. Right limb immersion with a lower temperature resulted in greater pain than that perceived on day 8. Daily repeated cryokinetic treatments are sufficient to produce habituation to cold-induced pain. Habituation was specific to the limb treated and temperature of habituation; thus, we conclude it is primarily physiological with some psychological influence. Athletic trainers are justified in telling patients who are undergoing ice water immersion that the cold pain will diminish with repeated applications.
 ...
PMID:Habituation to cold-pain during repeated cryokinetic sessions. 1655 65

We investigated habituation effects during thermal quantitative sensory testing (tQST) using 8 repetitive measurements for thermal detection and pain thresholds. The same measurements were repeated two days later. 39 healthy subjects and 36 patients with chronic non-neuropathic pain syndromes (migraine, tension-type headache, non-radicular back pain) were enrolled. The pain intensity was assessed using an 11-point (0-10) numerical rating scale. Measurements correlated significantly over the two days in both groups (r=0.41...0.62). Warm detection (WDT) and heat pain threshold (HPT) revealed no significant differences over these days. Cold detection (CDT) and pain thresholds (CPT) showed significant differences but these were small compared to the range of normal variability (CDTDelta -0.28 degrees C; CPTDelta 1.51 degrees C). On both days, WDT showed no habituation during measurements. Although there was a small difference in CDT and CPT between first and second measurement, there was no habituation beyond the second stimuli. In contrast, HPT significantly increased between first and sixth stimuli, indicating pronounced habituation. Average HPT of first to third measurement was significantly lower than HPT of the fourth to sixth assessment (45.9 degrees C; 47.7 degrees C) with a good day-to-day repeatability. Repeatability and habituation was identical in both groups. Ongoing pain intensity in the patient groups correlated significantly with CDT/WDT but not with CPT, HPT, indicating that ongoing pain might suppress the sensitivity to non-painful stimuli. In summary, tQST proved a reliable diagnostic tool for clinical practice. Day-to-day differences were small but without clinical relevance. Habituation was most pronounced for HPT, probably due to peripheral fatigue of the receptors.
 ...
PMID:Habituation and short-term repeatability of thermal testing in healthy human subjects and patients with chronic non-neuropathic pain. 1901 13


1 2 Next >>