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

During aortic clamping, drug protection of the myocardium, far from supplanting hypothermia, complements it, particularly in the case of left ventricular hypertrophy. Ultramicroscopy and new techniques of histobiological exploration of the myocite have enabled one to distinguish the lessions provoked by anoxia from those induced by reperfusion. At present, drug protection, extended to energetic solutions and electrolytes, aim at preserving energy metabolism by stocking of the substrate and at avoiding interferences which precipitate exhaustion of the adenosine triphosphate and phosphocreatinine reserves. In order to do this, hemodilution in particular is limited in subjects with decompensated cardiopathy; choice of anesthetics is orientated towards neuroleptanalgesia or fluothane, and it is attempted to neutralize the adrenergic reaction by the use of beta-blocking substances. Furthermore, it is preferred to interrupt electrogenesis at the stage of polarization: depolarizing cardioplegic solutions rich in potassium and sodium are rejected and in preference membrane stabilizers are used (procaine, magnesium, tetrodoxine...) The ultramicroscopic analysis of the structural modifications leads to sparing of the integrity of the lysosomial membrane by corticoids and alkalines. The use of calcium is deferred, anti-calcium techniques are even proposed (washing poor in calcium, verapamil). Cellular edema is prevented and treated by solution (mannitol - sorbitol) whose osmolarity must be less than 300 M osm/l. A conditioning of the biochemical and physicial structures and of cardiac work is being more and more thought of which leads to the classification of beta stimulating substances as negative, and their indications must be seriously thought of and used with reserve.
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PMID:[Drug protection of the myocardium during cardiac surgery]. 1 31

Taurine (10 and 20 micrograms) injected unilaterally into the lateral ventricle of rats caused an increase in core temperature. Bilateral injection of taurine 2.5 and 5 micrograms into the preoptic region of the anterior hypothalamus induced a dose-related hyperthermia: higher doses (10 micrograms) caused hypothermia. Intrahypothalamically taurine-induced hyperthermia was blocked by prior injection of strychnine hydrochloride (5 and 15 micrograms); doses which alone had no effect on core temperature. Of the other inhibitory amino acids injected intrahypothalamically hypotaurine also induced a hyperthermia. GABA (10 micrograms) caused hypothermia; glycine (10 micrograms) had no effect. Potassium (50 mM) stimulated release of radioactivity from superfused slices of anterior hypothalamus prelabelled with [3H]taurine in a calcium-dependent manner. A high affinity uptake mechanism with a Km of 8.5 microM was demonstrated with [3H]taurine into slices of anterior hypothalamus. Taurine may have a neurotransmitter role in the anterior hypothalamus but whether the body temperature effects represent physiological or pharmacological events remains to be established.
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PMID:Role of taurine as a possible transmitter in the thermoregulatory pathways of the rat. 3 17

The treatment of nephrolithiasis depends mainly on the type of stone present. Uric acid calculi can be dissolved by oral medication producing alkalinization of the urine. Cystin stones can only rarely be dissolved by oral administration of D-penicillamine. The best and least expensive prophylaxis is a high and constant fluid intake of 600 ml every 4 hours. This way the pathologically increased cystin excretion can be kept soluble. Calcium containing calculi and so-called "infection stones" need surgical intervention. Because of the high recurrence rate of renal stones every indication for an operative procedure has to be considered very carefully. For lasting results elimination of urinary obstruction is necessary. The treatment of choice of patients with staghorn calculus disease is surgical, even in the solitary kidney and in geriatric patients. As recent advances in the operative treatment of nephrolithiasis coagulum pyelolithotomy, intraoperative pyeloscopy, hypothermia and "bench surgery" (extra-corporeal renal surgery) are reviewed. Attempts to dissolve renal calculi by percutaneous nephrostomy as well as extraction of pelvic stones by the same procedure are mentioned. Finally, the importance of postoperative prophylaxis and the progress made in the medical treatment of calcium stones are pointed out.
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PMID:[Recent advances in the treatment of nephrolithiasis (author's transl)]. 4 17

Orthopaedic operations such as procedures for spinal deformity or operation for septic or loose total hip prosthesis are often associated with massive haemorrhage. Electrolyte analysis in 44 cases showed a low level of potassium. Rapid transfusion with stored blood appeared to have little effect on cardiac efficiency unless dilute calcium chloride was added. Alkaline preparations were used in patients with circulatory deficiency. Abnormalities of blood clotting were prevented by the use of fresh blood. Hypothermia and pulmonary complications also occurred and were eventually prevented by the use of assisted ventilation during the post-operative period.
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PMID:[Massive hemorrhage during major orthopedic surgery. Metabolic consequences]. 13 8

1. Adenosine 3',5'-monophosphate (cAMP), its dibutyryl derivative (Db-cAMP) and other adenine nucleotides have been micro-injected into the hypothalamic region of the unanaesthetized cat and the effects on body temperature, and on behavioural and autonomic thermoregulatory activities observed. 2. Db-cAMP and cAMP both produced hypothermia when applied to the pre-optic anterior hypothalamus. With Db-cAMP the hypothermia was shown to be dose dependent between 50 and 500 mug (0-096-0-96 mumole). 3. AMP, ADP and ATP also produced hypothermia when injected into the pre-optic anterior hypothalamus. 4. The order of relative potencies of the adenine nucleotides with respect both to the hypothermia produced and to the autonomic thermoregulatory effects observed were similar. Db-cAMP was most potent and cAMP least. 5. Micro-injection into the pre-optic anterior hypothalamus of many substances including saline produced in most cats a non-specific rise in body temperature apparently the result of tissue damage. Intraperitoneal injection of 4-acetamidophenol (paracetamol 50 mg/kg) reduced or abolished this febrile response. 6. The hypothermic effect of the adenine nucleotides has been compared with the effects produced in these same cats by micro-injections of noradrenaline, 5-hydroxytryptamine, a mixture of acetylcholine and physostigmine (1:1), EDTA and excess Ca2+ ions. 7. It is concluded that as Db-cAMP and cAMP both produce hypothermia, it is unlikely that endogenous cAMP in the pre-optic anterior hypothalamus mediates the hyperthermic responses to pyrogens and prostaglandins.
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PMID:The effects of cyclic adenosine 3',5'-monophosphate and other adenine nucleotides on body temperature. 17 Mar 96

In the unanesthetized rat, Ca++ ions in solutions ranging from 2.6 to 112.0 mM in excess of the normal level in CSF were applied at different sites in the brain and by three separate procedures, Colonic temperature was monitored and in certain experiments, the amount of food pellets and water consumed was measured simultaneously following the administration of excess Ca++ ions. An infusion into the lateral cerebral ventricle of excess calcium in a volume of 5.0 mul produced a concentration-dependent hypothermia, This fall in temperature was not attenuated by a prior intraventricular infusion of mecamylamine and often enhanced by atropine. Depending on the site, a microinjection of excess Ca++ ions in a volume of 0.5 to 1.0 mul directly into the hypothalamus produced hypothermia or feeding. The sites of maximum sensitivity at which excess calcium caused a decline in temperature were clustered in the caudal hypothalamus, whereas those at which calcium elicited feeding were distributed widely in caudo-lateral, medial and rostral hypothalamic areas. Push-pull perfusions at a rate of 20 to 25 mul per min for 10 to 20 min at homologous sites caused similar responses but the cation concentration required to evoke feeding or hypothermia was significantly less than that of either microinjection or intraventricular infusion. These findings demonstrate species continuity in the rat concerning anatomical localization of the postulated set-point mechanism for body temperature. Several different pathways in the feeding system are affected by an alteration in the hypothalamic level of calcium.
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PMID:Feeding and body temperature in the rat: diencephalic localization of changes produced by excess calcium ions. 18 84

The inotropic response induced by beta-adrenergic and H1 histaminergic receptor stimulation was characterized in guinea pig left atria by obtaining dose-response relationships for isoproterenol and histamine under various experimental conditions. Conditions (hypothermia, high frequencies of stimulation, and large extracellular calcium concentrations) which enhanced the ability of cardiac muscle to develop force also increased the sensitivity of the left atrium to isoproterenol while decreasing its efficacy. On the other hand, conditions which enhanced the ability of cardiac muscle to develop force depressed the efficacy of histamine to such an extent that the sensitivity to histamine was also decreased. In addition, conditions which markedly depressed the ability of cardiac muscle to develop force also decreased the efficacy and sensitivity to histamine. The data indicate that while beta-adrenoceptor stimulation results in an inotropic response under all conditions studied, stimulation of H1 histaminergic receptors results in an inotropic response only within a narrow range of experimental conditions.
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PMID:Characterization of the inotropic response induced by stimulation of beta-adrenergic and H1 histaminergic receptors in guinea pig left atria. 21 10

Direct cardiac and vascular effects of the antikaliuretic diuretic potassium-canrenoate were measured in cardio-surgical patients during extracorporal circulation and immediatly after operations, each time in neuroleptanalgesia. During "steady state" extracorporeal circulation (aorta cross-clamped, constant flow rate of heart-lung-machine, constant hypothermia), in 13 patients no significant influence on peripheral circulation was found after i.v.-injection of 800 mg potassium-canrenoate. Neither arterial perfusion pressure (representing an arterial vascular reaction) nor changes in oxygenator-volume (indicating venous vasodilation or contraction) demonstrated significant differences in comparison to a control group. After cardiac surgery haemodynamic measurements were performed for a period of 60 minutes in 10 patients given 800 mg potassium-canrenoate. In comparison with a control group (n = 6), no significant differences in arterial pressure, heart rate, cardiac index and pulmonary arterial pressure were found. Left ventricular measurements, using a catheter tip manometer, revealed no direct positive inotropic effect of a single i.v.-injection of potassium-canrenoate. In acute myocardial failure during anaesthesia or in "low cardiac ouptut" following open heart surgery no improvement in myocardial contractility is obtained by i.v.-application of potassium-canrenoate; at the present there seems no alternative to other positive inotropic agents such as calcium, glucagon, dopamine, orciprenaline and epinephrine.
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PMID:[Extrarenal effects of potassium-canrenoate. Haemodynamic investigations during neuroleptanalgesia in cardiosurgical patients (author's transl)]. 31 42

Calcium, other divalent cations, and calcium antagonists were tested for their ability to alter ethanol-induced sleeping time, hypothermia, and behavioral intoxication in mice and rats. Calcium given intraventricularly significantly enhanced sleeping time and behavioral intoxication in a dose-related manner. The ionophores X537A and A23187 accentuated the effect of a low dose of calcium, whereas the calcium chelators EDTA and EGTA decreased sleeping time. Calcium also enhanced tertiary butanol- and chloral hydrate-induced sleeping time. The effects of cations on ethanol-induced hypothermia were less significant. The results suggest the existence of a central calcium pool that is involved in ethanol intoxication in rodents.
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PMID:Ethanol: modifications of acute intoxication by divalent cations. 34 51

The hemodynamic and cardiac biochemical effects of global ischemic arrest during cardiopulmonary bypass (CPB) were studied in 54 animals and compared to seven animals without ischemic arrest. Ischemic arrest alone reduced the first derivative of left ventricular force of contraction (LV dF/dt) to 52 percent of control 10 minutes after resuming function and to 64 percent after 1 hour of reperfusion. Cardiac output was depressed to 52 percent of control after 10 minutes of reperfusion, and to 74 percent of control after 60 minutes of reperfusion. In six animals, moderate hypothermia (26 degrees C.) resulted in no protection of cardiac function from ischemic arrest, whereas profound hypothermia to 18 degrees C. resulted in values of LV dF/dt and cardiac output nearly equivalent to the CPB control group (no arrest). A continuous infusion of a hyperkalemic hypothermic solution slightly improved the degree of protection over hypothermia alone. The sarcoplasmic reticulum (SR) isolated from hearts which had undergone 60 minutes of ischemic arrest bound significantly less calcium when the isolation was done after 10 minutes of reperfusion as well as when it was done after 60 minutes of reperfusion. The time to spontaneous release of calcium from the SR also was significantly longer. Moderate hypothermia did not result in improved SR function, whereas deep hypothermia induced by local cooling or by hypothermic potassium infusion retained SR function at normal levels. Oxidative phosphorylation of mitochondria isolated after 60 minutes of reperfusion was also depressed. The mitochondrial respiration rate after normothermic ischemic arrest was 155 natoms of oxygen per minutes versus 237 natoms for the hypothermic hyperkalemic group. Respiratory control index was 5.5 for the normothermic group versus 9.4 for the hypothermic group. It is concluded that hypothermia, whether effected by surface cooling or by hypothermic potassium infusion, allowed full recovery of hemodynamic and biochemical functions within 1 hour of reperfusion.
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PMID:Myocardial depression after elective ischemic arrest. Subcellular biochemistry and prevention. 42 95


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