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

The variations of plasma glucose and insulin levels were studied during the course of deep hypothermia with cardiocirculatory arrest of 60 minutes in 3 experimental groups of dogs using a pump mixture of homologous blood and Ringer's lactate solution at 33%, 50%, and 100% hemodilution. Insulin levels decreased in all groups during the cooling period and remained stable throughout the rest of the experiments, showing a slight significant increase only at the end of rewarming after a temperature of 30 degrees C was reached. Glucose levels reacted similarly except during rewarming, where an important increase in glucose concentration greatly preceded the rise in insulin. We stress the importance of this dissociation in view of the possible clinical implications that may exist.
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PMID:Plasma levels of glucose and insulin during deep hypothermia with varying degrees of hemodilution in dogs. 86 70

Previous studies have shown that central injection of bombesin produces hypothermia in food-deprived, but not food satiated rats at normal ambient temperatures. The present study evaluated the effects of bombesin on core body temperature (Tb) and feeding behavior in rats pretreated with insulin. Administration of bombesin (0.25, 0.5, and 1.0 microgram) into the lateral cerebral ventricle produced hypothermia in rats injected with insulin (10 U/kg; i.m.). No significant change in core temperature was observed in control rats following bombesin. Insulin treatments significantly stimulated feeding behavior and the highest dose of bombesin significantly reduced feeding behavior. The results demonstrate bombesin-induced hypothermia under metabolic conditions similar to acute starvation. These findings are consistent with the hypothesis that bombesin-induced hypothermia in food-deprived rats is directly related to the fasting state.
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PMID:Bombesin produces hypothermia in insulin treated rats. 266 43

Anesthesia, surgery, and hypothermia are conventionally considered the major stress factors in the metabolic and hormonal responses to cardiac surgery. We compared these responses in 14 nondiabetics during and for 24 h after coronary artery bypass surgery; 8 received cardioplegic solutions (C+), and 6 did not (C-). The mean intraoperative glucose load in C+ was 106 g compared to 32 g in C-; postoperatively both groups received 50 g. Marked hyperglycemia (31.8 +/- 4.8 mmol/L) occurred during hypothermia in C+, but dropped to 18.9 mmol/L before surgery ended and to 11.2 +/- 1.1 mmol/L by 2 h postop. In contrast, C- showed constant mild hyperglycemia of 8.3-9.8 mmol/L throughout, significantly less than C+ until 1 h postop. Insulin was suppressed by 55% only during hypothermia, peaking with rewarming in C+ at 2,849 +/- 911 vs. 639 +/- 251 pmol/L in C- (P less than 0.05); as with glycemia, values were comparable after 2 h postop. The pancreatic beta-cell thus responded to hyperglycemia during restoration of normothermia, resulting in a rapid decline in glycemia. This occurred despite elevations in antiinsulin factors in both groups; GH was 14 +/- 4 micrograms/L, cortisol was 607 +/- 38.6 nmol/L, norepinephrine was 11.5 +/- 3.7 nmol/L, epinephrine was 13,863 +/- 3,875 pmol/L, and FFA were 0.36 +/- 0.05 g/L. Early postop, a secondary rise in stress hormones occurred in both groups. Maximal cortisol values were at 4 h (1,186 +/- 140 nmol/L) and peaks of norepinephrine (6.50 +/- 1.66 nmol/L), epinephrine (7,969 +/- 3,602 pmol/L), and FFA (0.27 +/- 0.03 g/L) occurred. The only significant glucagon elevation was at 24 h (C+, 464 +/- 53 ng/L; C-, 350 +/- 241 ng/L; P less than 0.02), Thus, 1) many metabolic responses during coronary artery bypass surgery are influenced by the glucose-containing cardioplegic solution; 2) hypothermia suppresses insulin secretion, but it responds thereafter despite marked elevations of catecholamines, and is associated with decreasing glycemia despite elevated antiinsulin factors; 3) a lesser but highly significant stress response corresponds to awakening from anesthesia; and 4) glucagon plays a minor role in intraoperative hyperglycemia; the rise at 24 h is unexplained.
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PMID:Hormonal and metabolic responses during coronary artery bypass surgery: role of infused glucose. 267 36

We describe two cases of dysgenesis of the corpus callosum demonstrated by magnetic resonance. The first patient presented with chronic hyponatraemia. Investigation demonstrated re-setting of the osmoreceptor and thirst centres. The calculated threshold for arginine vasopressin (AVP) release was reduced at 252 mosmol/kg while severe thirst was perceived at a plasma osmolality of 260 mosmol/kg. Insulin-induced hypoglycaemia produced an exaggerated AVP response. The second patient presented with hypothermia. The calculated threshold of AVP release was 296 mosmol/kg with increased sensitivity of AVP response to hypertonic saline. The plasma AVP response to insulin-induced hypoglycaemia was absent. Both cases had normal anterior pituitary function and psychological assessment showed a similar prefrontal defect. Specific tests of callosal function were normal. These cases illustrate the importance of undertaking complete neuroradiological assessment of cases of unexplained hypothalamic disease regardless of the age of presentation to avoid overlooking this rare congenital association.
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PMID:Hypothalamic disease in association with dysgenesis of the corpus callosum. 281 36

Administration of insulin 1 i.u./100 g of body weight to hypothermic rats causes a fall of glucose and lactate levels in the serum and a rise in myocardial glycogen level in relation to the group of control rats kept at room temperature and to the group of rats subjected only to hypothermia. Beta-adrenergic blockade (propranolol 0.6-1 mg/kg) caused no changes in the levels of carbohydrate metabolites in the serum of hypothermic rats but raised the myocardial glycogen level by 42% in relation to the animals subjected only to hypothermia. Simultaneous administration of both these agents during hypothermia produces a fall of the serum levels of glucose and pyruvate with a rise in the level of lactate, and raises the glycogen level in the myocardium (by about 161%) and in the skeletal muscle (by 54%) in relation to the rats subjected to hypothermia alone. Insulin and/or propranolol fail to prevent glycogen reserve exhaustion in the liver of hypothermic rats which could be due to activation of non-blocked alpha-adrenergic receptors or to the action of yet another glycogenolytic agent, e.g. glucagon, during hypothermia.
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PMID:Effects of insulin and beta-adrenergic blockade on certain indicators of carbohydrate metabolism in the blood and tissues of rats during short-lasting hypothermia. 613 94

Short-lasting hypothermia raises the FFA level in the blood and this rise is associated with increased lipid-mobilizing activity and higher lipolytic activity of the serum. Raised FFA level and increased lipid-mobilizing activity of the serum persist even when the degree of general anaesthesia is sufficient for preventing thermogenesis signs (shivering and piloerection) caused by falling body temperature. Beta-adrenergic blockade fails to abolish the effect of lipolysis activation caused by hypothermia. These observations suggest that during hypothermia in the blood of the animals appear factors stimulating lipolysis in the adipose tissue. One of these factors may stimulate tissue lipolysis independently of beta-adrenergic receptors. Insulin blocks significantly lipolytic processes in the adipose tissue of hypothermic animals, but its administration is connected with the danger of hypoglycaemia development.
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PMID:Effect of hypothermia on lipolytic processes in blood and adipose tissue of rat. 637 60

When using methods of perfusion to preserve the rat pancreas, we found that perfusion into the celiac axis was the most effective. The viability of the cadaver pancreas from decapitated rats preserved by perfusion into the celiac axis for 6 hours under various conditions of hypothermia, hyperbaria and oxygenation was investigated. The condition of perfusion affected the ratio of degenerative islets/normal islets in the pancreas. The ratio, under conditions of hypothermia and oxygenation was the lowest, while that under conditions of hyperbaria was the highest. Insulin-releasing activity of islets from 6-hour-perfusion-pancreas, under conditions of hypothermia and oxygenation was 86.5 per cent or more of that of the control. Stainings with fluorescent antibody and peroxidase antiperoxidase, revealed a large number of A and B cells in the islets of the pancreas, in cases of up to 6 hours of perfusion.
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PMID:Perfusion preservation of cadaver rat pancreas: I. Morphological observation and biological function of the islets. 637 97

We designed a new process for culturing pancreatic islets and applied this method to cultures of rat pancreatic islets which had degenerated during preservation by the perfusion-method for 6 hours under the condition of hypothermia and oxygenation. The objective was to determine the extent of the original function. Transplantation of these so-treated islets was also attempted. When pancreatic islets isolated from the pancreas after 6-hour-perfusion were cultured, morphological restoration was apparent within the first 3-4 days. Insulin contents of the culture media renewed every 3 days, ranged from 851 to 1,134 microU/ml/two islets during culture period of 21 days. In the glucose-loading test, insulin secretion of the islets was the same as that of islets in the control experiments. Transplantation of these islets into the portal vein of streptozotocin-induced diabetic rats resulted in a good recovery from the diabetic state.
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PMID:Perfusion preservation of cadaver rat pancreas: II. Culture after perfusion and successful transplantation. 642 98

Carbohydrate metabolism and insulin status have been studied in 89 patients with congenital heart valve defects operated on in conditions of profound perfusion-free hypothermic protection. It has been established that anesthesia, hypothermia, and surgical trauma are accompanied by hyperinsulinemia, which had nothing to do with the introduction of exogenic hormone. Insulin effect is attenuated and insulin resistance develops, which leads to a drop not only in glucose consumption but also in the consumption of glycolysis products. Single insulin injection during induction to anesthesia at a dose of 0.5 U/kg was insufficient for normalization of carbohydrate homeostasis. Glycolysis activation with a considerable increase in blood pyruvate level has been observed, which decreases lactate/pyruvate coefficient informative value at different stages of surgical treatment of heart valve defects.
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PMID:[Characteristics of carbohydrate metabolism regulation during correction of congenital heart defects and hypothermic protection without perfusion]. 808 Jan 21

Infants undergoing open-heart surgery with hypothermic cardiopulmonary bypass experience markedly elevated lactate and glucose levels. Reports in infants less than 10 kg show the elevated lactate to be progressive during the operative period. The pathogenesis of the hyperglycemia is not clear but may be caused by excess glucose administration, inadequate insulin response, or glucose regulatory hormone levels of glucagon, cortisol, and growth hormone. The purpose of this study is to confirm these findings and to investigate their pathogenesis. Serial blood samples were taken preoperatively, intraoperatively, and postoperatively during hypothermic cardiopulmonary bypass in nine infants of less than 10 kg. Samples were analyzed for levels of lactate, glucose, and regulatory hormones insulin, growth hormone, glucagon, and cortisol. Our study did not show a progressive accumulation of lactate. The elevated lactate level appears to come from the pump prime solution. The hyperglycemia is also from the pump prime solution, and there do not appear to be elevated levels of regulatory hormones intraoperatively. Insulin response during hypothermia is blunted; however, on rewarming the patient in the immediate postoperative period, a brisk insulin response is seen. The changes in levels of lactate and glucose and the regulatory hormones return to baseline at 24 hours with no further significant changes in the next 48 hours.
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PMID:Lactic acid changes during and after hypothermic cardiopulmonary bypass in infants. 847 97


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