Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Physiological roles have been suggested for prostacyclin in the cardiovascular system. Prostacyclin was administered by intravenous infusion to unanesthetized rats. Over a 24 hr period, 0.32 mg/kg/day caused only flushing of the ears. Larger doses (0.56 and 1 mg/kg/day) caused hypothermia, behavioral depression, and swelling of the paws. Cumulative dose-response curves for its depressor action were determined in both unanesthetized and anesthetized, vagotomized, ganglion-blocked rats. In unanesthetized rats, the threshold dose was about 0.1 ug/kg/min. Respiratory depression precluded doses larger than 1 ug/kg/min. In anesthetized rats, the threshold dose was about 0.001 ug/kg/min, and the maximally effective dose was about 0.1 micrograms/kg/min. At 0.032 ug/kg/min, blood pressure first fell and then rose slightly. This compensatory rise did not occur in nephrectomized rats, suggesting renin release as the mechanism. Intravenous infusion of 0.1 but not 0.01 ug/kg/min in unanesthetized rats doubled plasma renin activity. In saline-loaded unanesthetized rats, urine volume and urinary sodium excretion were decreased by 0.1 ug/kg/min of prostacyclin.
 ...
PMID:The cardiovascular pharmacology of prostacyclin (PGI2) in the rat. 37 17

Camels thrive in arid and semiarid areas, although food and water frequently are scarce. However, the mechanisms enabling camels to withstand food deprivation are poorly understood. In this study four female camels were totally deprived of food for 4 days. Their body weight decreased by 6%. Food deprivation caused no change in total plasma protein concentration in the camel, indicating that no alterations in plasma volume occurred. When the first meal was withheld water intake was unchanged. Next day the camels showed signs of hydration with a decreased plasma Na+ concentration and an increased excretion of diluted urine. In the afternoon water intake decreased. Urine K+ excretion fell the first day and urine volume and Na+ excretion from the third day. No activation of the renin-angiotensin-aldosterone system (RAAS) was observed. Plasma and urine urea concentration increased during food deprivation. Plasma glucose concentration and plasma cortisol and thyroxine levels did not change. Body temperature decreased during food deprivation. After refeeding, total plasma proteins increased temporarily by 12%, and a threefold increase in RAAS was seen, implying that both plasma volume and RAAs changed rapidly. Our results show that fluid balance was only slightly affected in the food-deprived camel. We suggest that strategies for the camel to endure food deprivation include maintenance of plasma volume and glucose concentration and a lowering of the body temperature.
 ...
PMID:Food deprivation and refeeding in the camel (Camelus dromedarius). 162 53

Adenosine exerts numerous effects in the central and autonomic nervous systems, most of which seem to be receptor mediated. Several studies have revealed two distinct receptors, based upon effects of adenosine on adenylate cyclase activity, designed A1 or A2 according to whether the cyclase is inhibited or activated. However, since not all adenosine receptors are linked to adenylate cyclase some authors base their classification on the rank orders of potencies of adenosine analogues in eliciting responses. The purine seems to function as a modulatory substance in the heart, blood, ileum, vas deferens, and adipose tissue. In addition, important responses to exogenously added adenosine are also induced in the bronchi, urinary bladder, taenia coli, parietal cells of the stomach and renin secretion. Adenosine and its analogues elicit anticonvulsant responses, sedation and hypothermia through their actions in the central nervous system. The mechanisms by which adenosine elicits its responses have not been clearly established. The activation of A1 receptors depresses the release of neurotransmitters and inhibit the influx of Ca into nerve terminals. Whether this effect is induced by interaction with Ca channels or by impairment of Ca dependent processes associated with neurotransmitter release is unknown. In the rat heart adenosine inhibits adenylate cyclase and subsequently the phosphorylation of L-type Ca channels, resulting in a decrease of calcium influx in the muscle cell. The responses to activation of A2 receptors in smooth muscle consist in relaxation presumptively by an increase of K current which would hyperpolarize the cell.
 ...
PMID:[Adenosine: physiological and pharmacological actions]. 215 91

A 37-year-old unmarried man was admitted because of gait disturbance and right hemifacial atrophy. Family history was unremarkable. He had an unconscious attack at age 13 and had writer's cramp since age 15. He was thin and lipodystrophic. In reviewing his portraits, hemifacial atrophy was considered to develop in his early teens and to be progressive since then. Pigmented gum, high arched palate, mild mental retardation, pseudo-Argyll Robertson's pupil, sexual impotence, amyotrophy of the left thigh and the right calf, and a limp due to bony abnormalities was detected. Serological tests for syphilis were negative. Bone X-rays disclosed coxa-deformance. Cerebrospinal fluid. EMG, EEG, muscle biopsy and brain CT were normal. Hearing was decreased to 20-35 dB bilaterally. Plasma norepinephrine levels were 450 pg/ml in the supine position and 539 pg/ml in standing. Plasma renin activity was 5.1-5.4 ng/ml/hr. Microneurography revealed highly accentuated muscle and skin sympathetic nerve activities. Hypothermia on the feet, reduced CVR-R and decreased mydriatic response to 5% cocaine instillation were present. Intravenous infusion of norepinephrine and intradermal injection of either acetylcholine or histamine revealed normal results. In the case, sympathicotonia due to dysfunction in the central nervous system is considered to be related to the pathogenesis of hemifacial atrophy.
 ...
PMID:[Progressive hemifacial atrophy with sympathetic nerve dysfunction of central origin]. 259 49

Polypeptides are endogenous agents, involved in the regulation of many physiologic functions and the pathogenesis of several diseases. Polypeptide antagonists form a group of new chemical entities which may provide valid therapeutic agents. Some polypeptides (angiotensin, kinins) are released through the action of proteolytic enzymes (renin, kallikreins) and act as hormones or autacoids; others (substance P, neurotensin) are synthetized by nervous cells to serve as neurotransmitters or neuromodulators. The main homeostatic role of the renin-angiotensin system is to uphold high systemic arterial blood pressure. Overproduction of renin and insufficient checking of renin secretion are among the most common causes of arterial hypertension. Several forms of arterial hypertension (neurovascular, idiopathic) benefit from a reduction in renin-angiotensin system activity. This is achieved either through decreasing renin secretion, by inhibiting conversion of angiotensin I into angiotensin II, or through blocking the peripheral actions (at the receptor sites) of angiotensin II. Renin secretion is very significantly reduced by beta-blocking agents (propranolol); conversion of angiotensin I into angiotensin II is inhibited by teprotide, captopril and their derivatives; peripheral actions of angiotensin II are blocked by saralasin. Bradykinin and related agents produce vasodilation, increase vascular permeability and stimulate pain fibers. Kinins thus reproduce the cardinal features of inflammation and are held to be mediators of the inflammatory reaction. The substance P neuropeptide is found in the brain and bowel; it may act as a transmitter of the sensation of pain at the spinal cord and central nervous system sites. Among other effects outside of the brain, substance P is a potent vasodilator and inhibits renin secretion. Neurotensin is a neuropeptide which produces hypothermia, muscular relaxation and analgesia. Outside of the brain, this peptide is involved in the regulation of gastric secretion, intestinal motility and insulin and glucagon secretion. The vasoactive intestinal peptide, found in certain cholinergic nerve endings, is a large peptide which inhibits gastric secretion, intestinal motility and vascular tone.
 ...
PMID:[Polypeptides and antagonists]. 620 6

The present studies were performed to investigate the metabolic role of the lungs in the renin-angiotensin system under hypothermia by measuring plasma renin activity, plasma angiotensin I (A I), plasma angiotensin II (A II), plasma aldosterone and plasma angiotensin converting enzyme activity on 14 patients who underwent open-heart surgery with surface-induced simple hypothermia. In addition, dog experiments were performed, in which changes of renal blood flow and angiotensin metabolism in lungs and kidneys under hypothermia were studied in vivo. The following results were obtained: 1) During and after open-heart surgery with surface-induced simple hypothermia, the homeostasis in the renin-angiotensin system is still maintained. 2) An increase of A II may play an important role in maintaining blood pressure under hypothermia. 3) Under hypothermia, the conversion of A I to A II in the kidneys may contribute to an increase of plasma A II.
 ...
PMID:Significance of renin-angiotensin system during and after surface-induced simple hypothermia in open-heart surgery. 630 Apr 82

Profound hypothermia below 20 degrees C achieved by surface cooling using simple ice water bath equipment and deep ether anaesthesia is used with the aid of autonomic nerve blocking agents to obtain cardiac arrest for periods of over one hour for open-heart surgery. Blood levels of ether were between 40.6 mg/dl and 285.7 mg/dl during anaesthesia. No arrhythmia occurred and vital signs were quite stable. Hypocarbia throughout the procedure, severe base deficit after circulatory arrest, spontaneous recovery of metabolic acidosis, and a nearly normal cH+ (pH) were observed. Catecholamine increased moderately after circulatory arrest, but was far below shock levels. Plasma renin activity was markedly elevated but angiotensin II stayed at non-significant levels throughout the procedure. Excess lactate showed no significant change. Hyperglycaemia was noted. The mortality rate was 7.7 per cent and neurological disorders occurred in less than 5.8 per cent of the recent 52 cases.
 ...
PMID:A study of profound hypothermia by surface cooling. 677 40

Of 11 patients who underwent elective aortocoronary bypass operation using nonpulsatile flow with moderate hypothermia (28 degrees C), 8 had hypertension defined as blood pressure of 160/100 mm Hg or greater. The plasma renin level was not elevated during bypass by postoperatively in the intensive care unit it became significant (P < 0.05) elevated. An increase in the release of renin was associated with a rise in systemic vascular resistance and coincided with the onset of hypertension. Although the values of plasma catecholamines were elevated during bypass and in the intensive care unit, they did not appear to contribute appreciably to increases in systemic resistance. The authors conclude that an increase in the release of renin is associated with increased vascular resistance and elevated blood pressure following myocardial revascularization.
 ...
PMID:Hypertension following myocardial revascularization: its prevalence and etiology. 700 71

Central and peripheral compartments of hypophyseo-adrenal regulation, the state of renin-angiotensin-aldosterone system (RAAS) and thyroid-stimulating functions of hypophysis have been assessed in 72 patients with heart valve defects operated under profound hypothermal perfusion. It has been established that cardiopulmonary bypass surgery with profound hypothermia is accompanied by moderate and reversible changes in the above parameters. The activity of hypophyseo-adrenal system and RAAS reaches the maximum during a warming-up period and then gradually decreases. TSH content considerably decreases in the early postoperative period. Cardiopulmonary bypass surgery with profound hypothermia causes more pronounced changes in neurohormonal regulation than heart valve correction under hypothermal perfusion, which might be associated with blood flow arrest in major vessels causing changes in peripheral metabolic processes.
 ...
PMID:[Hormonal regulation during cardiac surgery operations on the "dry" heart]. 806 1

Trandolapril (RU44570) was orally administered to dogs at a daily dose of 2.5, 25 or 250 mg/kg for 13 weeks. After the administration period, 25 and 250 mg/kg groups were observed for recovery for 4 weeks. The results obtained are as follows: 1. One male in the 250 mg/kg group showed decrease of food consumption and body weight, stomatitis, hematemesis, decumbence, hypothermia, and finally loss of reactivity to stimuli. This animal was killed because of these severe changes on the 39th day of administration. Among the surviving animals, a temporary loss of body weight was observed in a few animals of the 25 and 250 mg/kg groups, and a decreased food consumption was sporadically seen in a few animals of the 250 mg/kg group during the administration period. No abnormal changes were found in the clinical observation and water intake in the surviving animals. 2. The changes attributable to the pharmacological effect of RU44570 were a decreased activity of the angiotensin-converting enzyme, increases in plasma renin activity and urine volume, and decreases in specific gravity and concentrations of Na, K and Cl in the urine of every administration group. A decrease in blood pressure and an increase in the PAS and Bowie positive granules in the juxtaglomerular cells were also found in the 25 and 250 mg/kg groups. In addition, thickening of the afferent arteriolar wall of the glomeruli, a basophilic change of the renal tubular epithelial cells, and localized atrophy and hypertrophy of the renal tubules were observed in the 25 and 250 mg/kg groups, and increases in BUN, ALP and creatinine, and a slight dilation of the renal tubules were seen in the 250 mg/kg group. These observations indicated that RU44570 affected renal structure at a dose of 25 mg/kg or more renal function at a dose of 250 mg/kg. The animal killed in a moribund state showed nephrosis which consisted mainly of a moderate dilation of the renal tubules and vacuolation of the renal tubular epithelial cells, stomatitis, severe hemorrhage and necrosis with neutrophil infiltration in the fundus of the glandular stomach, atrophy of the hemopoietic system, and ectopic calcification in the heart, kidneys, stomach, trachea and alveolar wall. Changes in the kidneys similar to those observed in other animals were also detected. These changes suggested that this animal lapsed into a moribund state due to renal dysfunction and the resultant uremia.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:[Thirteen-week repeated dose toxicity by oral administration of trandolapril (RU44570) with 4-week recovery test in beagles]. 851 98


1 2 Next >>