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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A special circulating installation for topical hypothermia of the myocardium is proposed. An advantage of the installation is the possibility of the permanent controlled irrigation of the whole surface of the heart, especially of the posterior surface represented mainly by the left ventricle mass with the ice-cold solution.
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PMID:[Circulating system for performing immersion topical hypothermia of the myocardium]. 51 81

Cold blood with potassium, 34 mEq/L, was compared with cold blood and with a cardioplegic solution. Three groups of 6 dogs had 2 hours of aortic cross-clamp while on total bypass at 28 degrees C with the left ventricle vented. An initial 5-minute coronary perfusion was followed by 2 minutes of perfusion every 15 minutes for the cardioplegic solution (8 degrees C) and every 30 minutes for 3 minutes with cold blood or cold blood with potassium (8 degrees C). Hearts receiving cold blood or cold blood with potassium had topical cardiac hypothermia with crushed ice. Peak systolic pressure, rate of rise of left ventricular pressure, maximum velocity of the contractile element, pressure volume curves, coronary flow, coronary flow distribution, and myocardial uptake of oxygen, lactate, and pyruvate were measured prior to ischemia and 30 minutes after restoration of coronary flow. Myocardial creatine phosphate (CP), adenosine triphosphate (ATP), and adenosine diphosphate (ADP) were determined at the end of ischemia and after recovery. Changes in coronary flow, coronary flow distribution, and myocardial uptake of oxygen and pyruvate were not significant. Peak systolic pressure and lactate uptake declined significantly for hearts perfused with cold blood but not those with cold blood with potassium. ATP and ADP were lowest in hearts perfused with cardioplegic solution, and CP and ATP did not return to control in any group. Heart water increased with the use of cold blood and cardioplegic solution. Myocardial protection with cold blood with potassium and topical hypothermia has some advantages over cold blood and cardioplegic solution.
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PMID:Cold blood as the vehicle for potassium cardioplegia. 51 80

Systemic and central administration of methacholine (a synthetic choline derivative) both produced dose-dependent decreases in rectal temperature in rats at all the ambient temperatures studied. Both at room temperature (22 degrees C) and in the cold (8 degrees C), the hypothermia in response to methacholine application was brought about by both a decrease in metabolic heat production and an increase in cutaneous circulation. In the heat (29 degrees C), the hypothermia was due solely to an increase in respiratory evaporative heat loss. Furthermore, the methacholine-induced hypothermia was antagonized by central pretreatment of atropine (a selective blocker of cholinergic receptors), but not by the central administration of either 6-hydroxydopamine (a relative depletor of catecholaminergic nerve fibers) or 5,6-dihydroxytryptamine (predominately a serotonin depletor). The data indicate that activation of the cholinergic receptors within brain with methacholine decreases heat production and (or) increases heat loss which leads to hypothermia in rats.
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PMID:The role of the cholinergic system in the central control of thermoregulation in rats. 51 22

A male patient, aged 42, (No. 780624) was admitted to the Department of Neurosurgery of Hirosaki University Hospital, complaining recent weight loss, intolerance to cold and visual disturbance of the right eye. Ophthalmological examination revealed the optic atrophy with decreased visual acuity and concentric visual defect of the right eye. Endocrinological examination showed almost general suppression of adenohypophyseal function except abnormal high level resetting of cortisol diurnal rhythm. Radiological examination revealed the accessory middle cerebral artery and giant internal carotid aneurysm of the right side which was displayed by contrast-enhanced CT scan, with the enlarged sella turcica. Good cross filling was seen in left CAG through the anterior communicating artery. Extra-intracranial end to end anastomosis of the right internal carotid artery was performed with long venous graft under general anesthesia with hypothermia and induced hypotension, on Oct. 26 '78. Unroofing of the right optic canal was very useful to preserve the optic nerve, and the body of the giant aneurysm was opened and sutured tightly to reduce its mass effect. Interlacing suture for the anastomosis of the cervical internal carotid artery was employed successfully. The blood flow of the bypass graft, measured as enough volume with square wave flowmeter during the operation, was also confirmed with postoperative angiography. After the episodes of gastrointestinal bleeding, hypotensive attack and hemorrhagic infarction of right frontal base, the postoperative final result was successful and the patient is doing well, 6 months after the operation.
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PMID:[A case of extra-intracranial bypass venous graft for giant internal carotid aneurysm (author's transl)]. 52 56

Lean and genetically obese (ob/ob) male and female mice were given nicotine by subcutaneous injection. Nicotine treatment was found to raise plasma free fatty acids by similar amounts in both lean and obese mice. In lean mice, nicotine caused depression of rectal temperature at ambient temperatures 22-25 degrees C and partially prevented the hypothermia in these mice when exposed to cold (o-3 degrees C). In obese mice, nicotine treatment did not alter either rectal temperature at 22-25 degrees C or the severe hypothermia on cold exposure. It is proposed that the effect of nicotine on free fatty acids is due to release of adrenal catecholamines and that this mechanism operates in both lean and obese animals. It is also proposed that, in obese mice under normal circumstances, there is a defect in the central nervous control of this adrenergic mechanism which may contribute to the observed fall in body temperature at low ambient temperatures.
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PMID:Acute effects of nicotine on plasma free fatty acid concentrations and on the response to cold stress, in lean and obese (genotype ob/ob) mice. 52 20

Significance of the intercapsular brown adipose tissue (IBAT) in the thermal response to chlorpromazine (CPZ) during acute and chronic cold exposure was studied in rats. Adult male Wistar-Imamichi rats were exposed to 4 degrees C for 1 (cold-exposed) or 30 days (cold-acclimated). Intraperitoneal injection of 10 mg/kg CPZ caused a more marked and lasted hypothermia in acute cold-exposed rats as compared with that seen in control or in cold-acclimatized rats. Hypothermia induced by CPZ was unaffected by removal of IBAT either in control or acute cold-exposed rats. But in cold-acclimated rats, the removal of IBAT potentiated the hypothermia by CPZ. The relative weight of IBAT in cold-acclimated rats was about 3 times heavier than that in control and acute cold-exposed rats. CPZ had no effect on the relative weight of IBAT in all groups examined. Total lipids in IBAT showed no significant changes following CPZ administration in rats of all groups. In acute cold-exposed rats, serum FFA level progressively decreased after CPZ injection. The noradrenaline concentration in IBAT increased after chronic cold exposure and CPZ suppressed this elevation. The results suggest that the thermogenesis related sympathetic activity in the IBAT plays a mediatory role in thermal response to CPZ during cold acclimation.
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PMID:[Role of brown adipose tissue in the thermal response to chlorpromazine in rats during cold exposure (author's transl)]. 53 17

The Sudden Infant Death Syndrome (SIDS) is the most frequent cause of death in infants aged between one month and one year, yet its cause remains unknown. The present hypothesis is that most infants who die of SIDS have an abnormality of the catecholaminergic system, possible genetically determined, which results in a decreased thermogenic response to cold, owing to a deficiency in noradrenaline (NA), which eventually results in severe hypothermia. A series of complex, but interrelated reactions of the infant to the hypothermia and its consequences leads to death. The final mechanism of regulatory failure involves a deterioration of cardiorespiratory function resulting from hypoxia, metabolic acidosis and hypoglycemia. The etiology of "near miss" for SIDS is also unknown. It is postulated that these infants have a similar but milder deficiency which may be due, in part, to genetic factors. Determinations of central and peripheral catecholamines in "near miss" and normal infants will be performed to test this hypothesis.
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PMID:Sudden infant death syndrome: a testable hypothesis and mechanism. 53 16

1. The capacity ofr thermoregulation and thermogenesis in lean and genetically obese (ob/ob) mice has been investigated. 2. At 4 degrees C ob/ob mice rapidly die of hypothermia, because of a reduced capacity for cold-induced thermogenesis, but the animals are able to survive if previously adapted to 12 degrees C. 3. At all environmental temperatures between 30 degrees C and 10 degrees C the body temperature of ob/ob mice is 2.0-2.5 degrees C below that of lean animals. This may be due to a lower "setting" for body temperature. 4. At 34 degrees C the oxygen consumption of obese mice is greater than that of the lean animals while at 30 degrees C it is similar. When the environmental temperature is below 30 degrees C the oxygen consumption of the lean mice is greater. The obese animals therefore expend less energy on thermoregulatory thermogenesis. 5. The capacity for non-shivering thermogenesis was measured in lean and obese mice by investigating the effect of an injection of L-nor-adrenaline (1000 microgram/kg body weight) on the metabolic rate at 31 degrees C. Non-shivering thermogenesis was reduced by one-half in the obese animals. 6. One cause of the obesity of the ob/ob mouse is its high metabolic efficiency. We suggest that this high metabolic efficiency is due, at least in part, to less energy being expended on thermoregulatory thermogenesis.
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PMID:Thermoregulation and non-shivering thermogenesis in the genetically obese (ob/ob) mouse. 56 45

The changes in core temperature induced by low (5 mg/kg) and high (40 mg/kg) doses of morphine were compared in Wistar and Sprague-Dawley rats. In Sprague-Dawley rats the low dose caused a hyperthermia and the high dose a hypothermia but in Wistar rats both doses caused a hyperthermia. In either case the change in core temperature was antagonized by naloxone (2 mg/kg). Tolerance to the effects of the high dose of morphine developed in both strains of rat. Dextromoramide (3.75 and 15 mg/kg) also had an effect on core temperature, but in this case the responses of the strains were opposite to those seen with morphine. Laevomoramide was relatively ineffective. Naloxone (2 mg/kg) had no effect on the ability of rats of either strain to withstand heat or cold stress, providing no evidence that endogenous morphine-like substances have a physiological role in thermoregulation.
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PMID:Effects of morphine and related drugs on core temperature of two strains of rat. 57 May 6

The effect of d-amphetamine-induced hypothermia among rats maintained at a cold ambient temperature is related to its ability to release dopamine in the dopaminergic neurons in the mesolimbic pathway. However, the physiological mechanisms which mediate the hypothermia (heat loss or a decrease in heat production) are not known. Since we have failed to demonstrate effects induced by d-amphetamine on food intake or on heat sensors on the rat's tail we conclude that these are not the mechanisms involved in hypothermia. Effects of d-amphetamine on O2 consumption and CO2 production of rats kept at various ambient temperatures were investigated in order to find out if there is any relation between a decrease in body temperature and a decrease in the Basal Metabolic Rate. Neither such relations nor any relations between levels of body temperatures and levels of motor activity were found. The problem of the peripheral mechanisms involved in d-amphetamine-induced hypothermia remain as yet unidentified.
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PMID:D-Amphetamine thermal effects, metabolic rate and motor activity in rats. 59 Nov 93


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