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 following NEKY have been studied: 1-kynurenine (KYN), 3-hydroxyKYN (3HKYN), kynurenic (KYNA), anthranilic (ANT), 3-hydroxyANT (3HANT), quinolinic (QUIN), picolinic (PICA), xanthurenic (XAN), nicotinic (NIC) acids, 3-indole-pyruvate (IPA), nicotinamide (NAM). NEKY antagonize the central effects of precursors of serotonin (tryptophan and 5-HTP), and tryptamine as well. Seizures induced by central administration of KYN and QUIN are prevented by centrally injected dopamine and diminished by noradrenaline and adrenaline. KYN, 3HANT, PIC and NIC potentiate oxotremorine hypothermia mediated by acetylcholine. Central administration of GABA, glycine or taurine, as well as proline and melatonin, prevented seizures induced by QUIN and KYN. Behavioral inhibitory effects of these amino acids are diminished by pretreament with KYN, 3HKYN and QUIN. Elevation of concentrations of corticosteroids is resulted in rise of level of NEKY due to hormonal induction of liver tryptophan pyrrolase and brain 2,3 dioxigenase. NEKY, in their turn, activate both enzymes. Thus, a "vicious circle" is formed and it supports an elevated level of NEKY for a long time, hours and days. Long-lasting increased concentrations of NEKY in tissues can lead to significant after-effects and numerous pathogenic consequences. One can not exclude that a rise of the level of some NEKY, e.g. KYNA, IPA, PIC and XAN, may play an "adaptogenic" role in stress antagonizing some pathologic effects of KYN and QUIN, e.g. anxiogenic, neurotoxic and proconvulsive. It has been demonstrated that the excitatory NEKY, KYN, 3HKYN, QUIN, possess an anxiogenic activity in the standard animal models of anxiety. NEKY with opposite neuroactivities, namely KYNA, IPA, PICA and XAN, have a pharmacological profile of anxiolytics and antagonize both anxiogenic NEKY and standard anxiogens, like caffeine, pentylenetetrazole and yohimbine. Major emphasis is made on KYN as a putative endogenous anxiogen. Studies on the interaction of NEKY with other endogenous metabolites involved in anxiety (beta-phenylethylamine, cholecystokynine, melatonin) are in progress.
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PMID:Neurokynurenines (NEKY) as common neurochemical links of stress and anxiety. 1520 24

The present study determined the effect of caffeine co-administration on the core body temperature response and long-term serotonin (5-HT) loss induced by methylenedioxymethamphetamine (MDMA; "Ecstasy") and its metabolite methylenedioxyamphetamine (MDA; "Love") to rats. In group-housed animals, caffeine (10 mg/kg) enhanced the acute toxicity of MDMA (15 mg/kg) and MDA (7.5 mg/kg), resulting in an exaggerated hyperthermic response (+2 degrees C for 5 h following MDMA and +1.5 degrees C for 3 h following MDA) when compared to MDMA (+1 degree C for 3 h) and MDA (+1 degree C for 1 h) alone. Co-administration of caffeine with MDMA or MDA was also associated with increased lethality. To reduce the risk of lethality, doses of MDMA and MDA were reduced in further experiments and the animals were housed individually. To examine the effects of repeated administration, animals received MDMA (10 mg/kg) or MDA (5 mg/kg) with or without caffeine (10 mg/kg) twice daily for 4 consecutive days. MDMA and MDA alone induced hypothermia (fall of 1 to 2 degrees C) over the 4 treatment days. Co-administration of caffeine with MDMA or MDA resulted in hyperthermia (increase of up to 2.5 degrees C) following acute administration compared to animals treated with caffeine or MDMA/MDA alone. This hyperthermic response to caffeine and MDMA was not observed with repeated administration, unlike caffeine + MDA, where hyperthermia was obtained over the 4 day treatment period. In addition, 4 weeks after the last treatment, co-administration of caffeine with MDA (but not MDMA) induced a reduction in 5-HT and 5-hydroxyindole acetic acid (5-HIAA) concentrations in frontal cortex (to 61% and 58% of control, respectively), hippocampus (48% and 60%), striatum (79% and 64%) and amygdala (63% and 37%). However, when caffeine (10 mg/kg) and MDMA (2.5 mg/kg) were co-administered four times daily for 2 days to group-housed animals, both hyperthermia and hippocampal 5-HT loss were observed (reduced to 68% of control). Neither MDMA nor MDA alone induced a significant reduction in regional 5-HT or 5-HIAA concentrations following repeated administration. In conclusion, caffeine promotes the acute and long-term toxicity associated with MDMA and MDA. This is a serious drug interaction, which could have important acute and long-term health consequences for recreational drug users.
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PMID:Caffeine promotes hyperthermia and serotonergic loss following co-administration of the substituted amphetamines, MDMA ("Ecstasy") and MDA ("Love"). 1618 83

Components of excitation-contraction (EC)-coupling were compared at 37 degrees C and 22 degrees C to determine whether hypothermia altered the gain of EC coupling in guinea pig ventricular myocytes. Ca(2+) concentration (fura-2) and cell shortening (edge detector) were measured simultaneously. Hypothermia increased fractional shortening (8.3+/-1.7 vs. 2.6+/-0.3% at 37 degrees C), Ca(2+) transients (157+/-33 vs. 35+/-5 nM at 37 degrees C), and diastolic Ca(2+) (100+/-9 vs. 60+/-6 nM at 37 degrees C) in field-stimulated myocytes (2 Hz). In experiments with high-resistance microelectrodes, the increase in contractions and Ca(2+) transients was accompanied by a twofold increase in action potential duration (APD). When voltage-clamp steps eliminated changes in APD, cooling still increased contractions and Ca(2+) transients. Hypothermia increased sarcoplasmic reticulum (SR) Ca(2+) stores (83+/-17 at 37 degrees C to 212+/-50 nM, assessed with caffeine) and increased fractional SR Ca(2+) release twofold. In contrast, peak Ca(2+) current was much smaller at 22 degrees C than at 37 degrees C (1.3+/-0.4 and 3.5+/-0.7 pA/pF, respectively). In cells dialyzed with sodium-free pipette solutions to inhibit Ca(2+) influx via reverse-mode Na(+)/Ca(2+) exchange, hypothermia still increased contractions, Ca(2+) transients, SR stores, and fractional release but decreased the amplitude of Ca(2+) current. The rate of SR Ca(2+) release per unit Ca(2+) current, a measure of EC-coupling gain, was increased sixfold by hypothermia. This increase in gain occurred regardless of whether cells were dialyzed with sodium-free solutions. Thus an increase in EC-coupling gain contributes importantly to positive inotropic effects of hypothermia in the heart.
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PMID:Hypothermia increases the gain of excitation-contraction coupling in guinea pig ventricular myocytes. 1861 12

Cerebral palsy is the most prevalent cause of persisting motor function impairment with a frequency of about 1/500 births. In developed countries, the prevalence rose after introduction of neonatal intensive care, but in the past decade, this trend has reversed. A recent international workshop defined cerebral palsy as "a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain." In a majority of cases, the predominant motor abnormality is spasticity; other forms of cerebral palsy include dyskinetic (dystonia or choreo-athetosis) and ataxic cerebral palsy. In preterm infants, about one-half of the cases have neuroimaging abnormalities, such as echolucency in the periventricular white matter or ventricular enlargement on cranial ultrasound. Among children born at or near term, about two-thirds have neuroimaging abnormalities, including focal infarction, brain malformations, and periventricular leukomalacia. In addition to the motor impairment, individuals with cerebral palsy may have sensory impairments, cognitive impairment, and epilepsy. Ambulation status, intelligence quotient, quality of speech, and hand function together are predictive of employment status. Mortality risk increases incrementally with increasing number of impairments, including intellectual, limb function, hearing, and vision. The care of individuals with cerebral palsy should include the provision of a primary care medical home for care coordination and support; diagnostic evaluations to identify brain abnormalities, severity of neurologic and functional abnormalities, and associated impairments; management of spasticity; and care for associated problems such as nutritional deficiencies, pain, dental care, bowel and bladder continence, and orthopedic complications. Current strategies to decrease the risk of cerebral palsy include interventions to prolong pregnancy (eg, 17alpha-progesterone), limiting the number of multiple gestations related to assisted reproductive technology, antenatal steroids for mothers expected to deliver prematurely, caffeine for extremely low birth weight neonates, and induced hypothermia for a subgroup of neonates diagnosed with hypoxic-ischemic encephalopathy.
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PMID:Diagnosis, treatment, and prevention of cerebral palsy. 1898 5

The effects of the non-selective adenosine A(1)/A(2) receptor antagonist caffeine on behavior and thermoregulation in chronic unpredictable stress (CUS) model of depression was studied in Wistar rats. In the open field (OF) test, caffeine dose-dependently increased motor activity while decreased grooming and time spent in the corner. Five-week exposure to CUS procedure had the opposite effect in rats. Caffeine reversed CUS-induced effects on the above mentioned parameters. Caffeine (40 mg/kg) increased the motor activity in plus maze (PM) test while at doses of 20 and 40 mg/kg it decreased the number of entries in the open arms. Whereas CUS did not change the level of anxiety, caffeine (2, 20 and 40 mg/kg) administered after CUS diminished it by increasing the time in open arms. Caffeine dose-dependently decreased the immobility time while CUS had the opposite increasing effect in forced swimming test (FST). Caffeine at doses of 20 and 40 mg/kg reversed the effect of CUS on immobility in FST. Caffeine produced dose-dependent rice of body temperature in both non-treated and CUS-treated rats. The hyperthermic effect in normal rats pretreated with caffeine lasted about 90 min while in caffeine-pretreated rats exposed to CUS it lasted about 150 min. High dose of caffeine (100mg/kg) induced significant hypothermia between 90th and 150th minute in control rats and hyperthermia between 30th and 60th minute in CUS-treated rats. These results suggest a putative role of this methylxanthine in the adaptive responses to chronic unpredictable stress stimuli.
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PMID:Dose-dependent effects of caffeine on behavior and thermoregulation in a chronic unpredictable stress model of depression in rats. 2012 70

When asked to address the above question, findings that appeared to be among the most relevant included (1) interventions in the delivery room directed at supporting the physiological transition from intrauterine to extrauterine life rather than actively intervening in it; (2) recent data suggesting that keeping extremely low-gestational age neonates at a pulse oximeter saturation (SpO(2)) of 91-95% would increase their chances of survival compared with aiming for lower SpO(2) values; (3) using caffeine citrate in infants <1250 g with apnoea of prematurity improves neurodevelopmental outcome; (4) injecting antivascular epithelial growth factor into the vitreous seems to be an effective treatment for retinopathy of prematurity and (5) moderate hypothermia for perinatal hypoxic-ischaemic encephalopathy increases the likelihood of survival without neurological impairment. Here, data that support these recent changes in approach will be presented and discussed.
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PMID:What are the main research findings during the last 5 years that have changed my approach to clinical practice? 2186 86

Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+) homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+) current (I(Ca)) was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca) did not compromise the Ca(2+)-induced Ca(2+) release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca). Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+) removal were more rapid in ground squirrels. Ca(2+) sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca) threshold, low SR Ca(2+) leak and rapid cytosolic Ca(2+) clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+) homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+) overload-related heart diseases.
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PMID:Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis. 2193 66

From July 2010 through June 2011, the number of U.S. service members treated for cold injuries (n=557) was similar to recent prior years. The most frequently reported cold injury was hypothermia in the Marine Corps and frostbite in the other service branches. Cold injury rates were generally highest among service members who were less than 20 years old and of black, non-Hispanic race/ethnicity. Service members who train in wet and freezing conditions -- and their supervisors at all levels -- should know the signs of cold injury, ensure adequate hydration, and avoid tobacco, caffeine, and vasoconstrictive medications.
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PMID:Update: cold weather injuries, U.S. Armed Forces, July 2006-June 2011. 2206 Feb 46

p-Synephrine is an adrenergic amine found in Citrus aurantium L. fruits and has been used for weight loss in dietary supplements. There are commercial products containing this substance associated to caffeine, salicin, and ephedrine. The aim of this study was to evaluate the acute toxicity of this mixture in mice of both sexes. The significative results observed after acute oral administration to male and female mice of 300, 350, and 400 mg/kg total of p-synephrine, ephedrine, salicin, plus caffeine in a 10:4:6:80 w/w ratio included a reduction in locomotor activity and ptosis in all treated groups for both sexes. Seizures were also observed in male (400 mg/kg) and female groups (350 and 400 mg/kg). Gasping and tearing were observed in males. Salivation (400 mg/kg), agitation (350 and 400 mg/kg), and piloerection (all treated groups) were significantly observed only in females. Deaths occurred in males at 350 and 400 mg/kg treated groups and the necropsy showed cardiopulmonary hemorrhage. A reduction in locomotor activity was confirmed through the spontaneous locomotor activity test, in which the number of crossings considerably decreased (P < .01) in all treated groups. The rotarod test showed a decrease in motor coordination at 400 mg/kg. Body temperature decreased significantly (P < .01) in all treated groups compared to controls. The results suggested clear signs of toxicity of p-synephrine, ephedrine, salicin, and caffeine association; this toxicity augments the attentiveness on commercial products containing this mixture, given the expressive number of adverse events related to its utilization.
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PMID:Toxicological effects of a mixture used in weight loss products: p-synephrine associated with ephedrine, salicin, and caffeine. 2240 69

A 27-year-old woman with a history of depression and previous overdose presented within 60 min of ingestion of 50 g of caffeine powder. Initially alert but hypotensive and tachycardic, the patient developed a broad complex tachycardia followed by a seizure and multiple ventricular fibrillation (VF) arrests. Following multiple defibrillations for VF, eight cycles of cardiopulmonary resuscitation and treatment with amiodarone, lidocaine, magnesium and potassium supplementation, the patient went to the intensive care unit (ICU). While there, the patient had further VF and required haemofiltration for a profound metabolic acidaemia with cardiac rhythm instability. She developed a postcardiac arrest systemic inflammatory response syndrome with episodes of acute pulmonary oedema, profound vasoplegia, hypothermia and coagulopathy. After 5 days in the ICU, the patient was stable enough to be transferred to the ward, with a persistent sinus tachycardia, and was discharged 3 days later with cardiology and psychiatry follow-up.
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PMID:Survival of a highly toxic dose of caffeine. 2339 22


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