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)

The binding of [3H]11-OH-delta 9-tetrahydrocannabinol-1, 1-dimethyl-heptyl (THC-DMH), a recently synthesized cannabinoid analog, was characterized in an in vitro brain slice binding assay and compared to that obtained with [3H]CP-55,940, the radiolabeled ligand used originally to characterize cannabinoid binding sites. The binding of both [3H]CP-55,940 and [3H]11-OH-delta 9-THC-DMH exhibited high affinity (Kd of 19 +/- 3 and 29 +/- 9 nM, respectively), and was saturable, reversible and specific. Values of maximal concentration of receptors determined for [3H]11-OH-delta 9-THC-DMH and [3H]CP-55,940 were 4.0 +/- 0.3 and 3.0 +/- 0.5 pmol/mg of protein, respectively. The distribution of [3H]11-OH-delta 9-THC-DMH and [3H]CP-55,940 binding in 30-microns rat brain sections was then compared by autoradiographic analysis. The binding of both ligands was densest in the basal ganglia (substantia nigra pars reticulata, globus pallidus, entopeduncular nucleus and regions of the caudate putamen) and cerebellum (molecular layer). Low levels of binding were observed in discrete brain regions including the brain stem (medulla and pons), thalamic nuclei, hypothalamus, corpus callosum and the deep nuclear layer of the cerebellum. Intermediate levels of binding were seen in layers I and VI of the cortex, and the dentate gyrus and CA pyramidal cell regions of the hippocampus. The ability of selected cannabinoid analogs to compete with [3H]11-OH-delta 9-THC-DMH binding was determined. The Ki's were correlated to the in vivo potencies for producing catalepsy, antinociception, hypothermia and decreasing spontaneous locomotor activity in mice (correlation coefficients > 0.86).(ABSTRACT TRUNCATED AT 250 WORDS)
J Pharmacol Exp Ther 1992 Dec
PMID:Characterization and autoradiographic localization of the cannabinoid binding site in rat brain using [3H]11-OH-delta 9-THC-DMH. 133 65

The effect of selective mu-, kappa-, and delta-agonists on brain surface temperature (Tb), oxygen consumption (Vo2), and heat exchange (Q) was studied in unrestrained, male Sprague-Dawley rats using whole-body calorimetry. Hyperthermia, produced by PL-017 (1.86 nM) given ICV, resulted from increased Vo2 and reduced Q during the first 15-45 min postinjection. Tb returned to control levels due to a combination of increased Q and reduced Vo2. PL-017-induced hyperthermia was abolished by the mu-selective antagonist CTAP (0.75 nM). Dynorphin A1-17 (4.65 nM), a kappa-selective agonist, reduced both Vo2 and Q, resulting in hypothermia that was blocked by the kappa-selective antagonist nor-binaltorphimine (25 nM). The delta-selective agonist DPDPE (4.64 nM) caused no significant changes in Tb, Vo2, or Q. The data indicate that central stimulation of the mu- and kappa-opioid receptors affects both oxidative metabolism and heat exchange, which result in a change in Tb. These alterations can be prevented with selective opioid antagonist pretreatment.
Pharmacol Biochem Behav 1992 Dec
PMID:Effect of mu-, kappa-, and delta-selective opioid agonists on thermoregulation in the rat. 136 92

The present study tested the hypothesis that the attenuation by oxytocin of tolerance to ethanol-induced hypothermia relies upon an impairment of the putative conditioning processes underlying environment-specific tolerance. According to the conditioning model of tolerance, such tolerance occurs because an opposite compensatory response conditioned to ethanol-paired cues attenuates ethanol's effects. Tolerance to ethanol-induced hypothermia was established to a particular environment over 4 days by injecting mice (daily) with oxytocin 2 h before ethanol, outside the colony room. As controls, other mice were injected similarly but following testing in the animal room. We found that oxytocin suppressed the conditioned compensatory response, revealed by injecting saline to every group in the tolerance-associated environment. These results suggest that oxytocin acted, at least partly, via an inhibition of the associative learning processes that facilitate tolerance development.
Pharmacol Biochem Behav 1992 Dec
PMID:Oxytocin blocks the environmentally conditioned compensatory response present after tolerance to ethanol-induced hypothermia in mice. 136 94

Sickle hemoglobinopathies include sickle cell disease, sickle-C disease, and sickle-beta thalassemia. Patients with these disorders commonly suffer a multitude of destructive events to vital organs, especially to the central nervous system, the spleen, the kidney, the lung, and the heart as a result of microvascular plugging by the sickled erythrocytes. Thoughtful preparation for anesthesia and operation, especially when directed by experienced individuals, can greatly reduce the hazard of inducing the sickle crises that formerly plagued individuals with sickle hemoglobinopathies who faced major operations under general anesthesia. The patient must be free of any acute illness, especially one involving the respiratory system. Adequate hydration preoperatively combined with avoiding perioperative hypoxia, hypothermia, and acidosis, the triggers for sickling, will go far toward avoiding sickle-induced complications. Modern transfusion therapy, consisting of multiple small transfusions of Hb A erythrocytes administered over several weeks prior to the operation, not only corrects the chronic anemia but suppresses erythropoiesis of cells containing Hb S in the patient's bone marrow and leaves him or her with a majority of cells containing Hb A. This provides a safety net in case a sickle-inducing insult occurs despite the best efforts to avoid one. Individuals with sickle hemoglobinopathies may require any of the operations common to all children, for example, herniorrhaphy, appendectomy, tonsillectomy, and circumcision, but a significant number will develop calcium bilirubinate cholelithiasis and possibly cholecystitis as a result of the continual increased load of bile salts resulting from the shortened lifespan of the cells containing Hb S. Also, although most individuals with Hb S will gradually suffer splenic infarction by late childhood, a significant number of infants will experience acute splenic sequestration crisis, a life-threatening entity, the recurrence of which is prevented by splenectomy. Several publications have demonstrated that such surgical procedures can be performed in large numbers of patients with sickle hemoglobinopathies without deaths and with minimal morbidity.
Surg Clin North Am 1992 Dec
PMID:Surgical management of children with hemoglobinopathies. 144 Jan 54

Barbiturates have been used as a method of cerebral protection in patients undergoing open heart operations. Phosphorus 31 nuclear magnetic resonance spectroscopy was used to assess barbiturate-induced alterations in the cerebral tissue energy state during cardiopulmonary bypass, hypothermic circulatory arrest, and subsequent reperfusion. Sheep were positioned in a 4.7-T magnet with a radiofrequency coil over the skull. Nuclear magnetic resonance spectra were obtained at 37 degrees C, during cardiopulmonary bypass before and after drug administration at 37 degrees C and 15 degrees C, throughout a 1-hour period of hypothermic circulatory arrest, and during a 2-hour reperfusion period. A group of animals (n = 8) was administered a bolus of sodium thiopental (40 mg/kg) during bypass at 37 degrees C followed by an infusion of 3.3 mg.kg-1 x min-1 until hypothermic arrest. A control group of animals (n = 8) received no barbiturate. The phosphocreatine/adenosine triphosphate ratio, reflecting tissue energy state, was lower during cardiopulmonary bypass at 15 degrees C in the treated animals compared with controls (1.06 +/- 0.08 versus 1.36 +/- 0.17; p < 0.001). Lower phosphocreatine/adenosine triphosphate ratios were observed throughout all periods of arrest and reperfusion in the barbiturate-treated animals compared with controls (p < or = 0.01). Thiopental prevented the increase in cerebral energy state normally observed with hypothermia and resulted in a decrease in the energy state of the brain during hypothermic circulatory arrest and subsequent reperfusion. These results suggest that thiopental administration before a period of hypothermic circulatory arrest may prove detrimental to the preservation of the energy state of the brain.
Ann Thorac Surg 1992 Dec
PMID:Barbiturates impair cerebral metabolism during hypothermic circulatory arrest. 144 98

Magnetic resonance (MR) may be used for repeatedly and non-invasively imaging the brain. Until now, no studies have used this approach to study the effects of carbon monoxide (CO) poisoning in a defined animal model. Conscious, Levine-prepared female rats (unilateral carotid artery and jugular vein occlusion) were exposed to 2400 ppm CO for 90 min, with or without the infusion of 50% glucose solution; CO-stimulated increases in blood glucose and lactate occurred in both groups, while blood pressure and body temperature fell. One to four hours following termination of CO exposure, increased cortical pixel intensity, cortical surface area and brain midline shift were observed on the operated side of the brain in some rats of both groups (i.e. responders = R), providing evidence of edema. At sacrifice, 5 h following termination of CO exposure, gross water content was increased on the left side in the corresponding cortical slices in R rats, providing another measure of edema. Significant positive correlations were found between left to right pixel intensity difference and water content difference, and between the extent of midline shift and water content difference. The elevations of blood glucose and lactate concentrations, and the magnitudes of CO-induced hypothermia and hypotension were similar to those in past studies, but appeared to exert no effect on the severity of cortical edema in terms of differences in pixel intensity, surface area, midline shift or gross tissue water content. Thus, the observed differences between the R rats is not explained by the available data.(ABSTRACT TRUNCATED AT 250 WORDS)
J Appl Toxicol 1992 Dec
PMID:Magnetic resonance imaging of the rat brain following acute carbon monoxide poisoning. 145 74

Although hypothermia is a serious and sometimes fatal condition, prompt recognition and institution of appropriate rewarming techniques may save even profoundly affected persons. The diagnosis of hypothermia should be considered when patients present with alterations of cerebral function without apparent explanation, especially in the presence of underlying predisposing illnesses and conditions. When hypothermia is suspected, an accurate core temperature must be obtained. Application of rewarming techniques appropriate to the degree of hypothermia may be lifesaving. Conservative use of pharmacotherapy is warranted.
Postgrad Med 1992 Dec
PMID:Hypothermia. Saving patients from the big chill. 145 72

Thermoregulatory vasoconstriction may serve to separate and limit heat transfer between peripheral and central thermal compartments, in effect providing a thermal buffer for central temperature. We hypothesized that thermoregulatory vasoconstriction would limit heat transfer to the central compartment in patients warmed cutaneously. Hypothermic patients (central temperatures < 35 degrees C) recovering from surgery were randomly assigned to receive forced-air warming (n = 6) or warmed cotton blankets (n = 6). The forced-air warmer delivers approximately 50 W of heat, compared to a heat loss of approximately 50 W with warmed cotton blankets. Despite a significantly greater increase in mean skin-surface temperature with forced-air warming, central temperature in the two groups did not significantly differ. All patients vasoconstricted and there was no difference in oxygen consumption between groups. These data confirm that thermoregulatory vasoconstriction limits heat transfer from peripheral to central thermal compartments and impedes skin surface warming of the body core.
Aviat Space Environ Med 1992 Dec
PMID:Limited heat transfer between thermal compartments during rewarming in vasoconstricted patients. 145 17

Changes in systemic haemodynamic variables (mean arterial pressure, MAP; heart rate, HR; cardiac output, Qc), in oxygen consumption, VO2, and in ventilation (minute ventilation, V; respiratory frequency, f; tidal volume, VT; and arterial blood gases) with particular attention to respiratory times (duration of inspiration, TI; duration of expiration, TE; duration of the breathing cycle, TTOT), to respiratory timing (TI/TTOT) and respiratory drive (VT/TI) were studied during moderate progressive hypothermia (36 degrees C to 28 degrees C) during stable halothane anaesthesia (MAC = 1.5) in six dogs. MAP, HR and Qc decreased; V and f decreased, the decrease in f being correlated with that in temperature (r = 0.66; P < 0.01). Tidal volume did not change. The PaO2 and pHa decreased while PaCO2 increased slightly. The decrease in ventilation was related to changes in respiratory times (TI and TE) which increased (TE more than TI) and in respiratory drive (VT/TI which decreased due to the increase in TI). The relation between VT/TI and TI/TTOT changes was not constant during cooling. Changes in respiratory times and drive could be due to the effect of cold on medullar respiratory control.
Can J Anaesth 1992 Dec
PMID:[Respiratory effects of moderate hypothermia (36 degrees C-28 degrees C) in dogs under halothane anesthesia]. 146 37

Although a role for free radicals in myocardial damage during cardiopulmonary bypass for open heart surgery has been postulated, direct evidence of free radical production as well as consumption of tissue antioxidants such as vitamin E is still lacking. Twenty patients (age 26-66 yr, mean 48) undergoing elective open heart surgery with moderate hypothermia, and cold crystalloid cardioplegia, were studied. Cardiopulmonary bypass time was 61.4 +/- 31.2 min. The specimens of atrial tissue collection before and after cardiopulmonary bypass, were immediately frozen in liquid nitrogen. Mean vitamin E atrial content, measured by reverse phase HPLC, was 355 +/- 249 pmol/mg of dry weight basally, 135 +/- 85 pmol/mg (p < 0.05) at the end of the ischemic period and 405 +/- 288 pmol/mg after the reperfusion period (p < 0.01). Microscopic examination of right atrial biopsies ruled out differences in fibrosis or cellular damage as the cause of vitamin E changes. Although a great basal variability in atrial vitamin E content was observed, which was independent of age, sex and clinical status, a reproducible and substantial decrease in atrial vitamin E content after cardiopulmonary bypass occurred (mean reduction 45 +/- 17% and 55 +/- 22%, respectively, after ischemia and after reperfusion). This was directly related to the aorta cross-clamping duration and partially to the minimum temperature achieved. In conclusion, apart from the great variability observed in basal vitamin E tissue content, vitamin E was always reduced during cardiopulmonary bypass, suggesting an oxidative stress on the myocardium during open heart surgery.
Int J Cardiol 1992 Dec
PMID:Myocardial vitamin E is consumed during cardiopulmonary bypass: indirect evidence of free radical generation in human ischemic heart. 146 17


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