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

Seventy-two healthy dogs required sedation and analgesia for a variety of procedures causing discomfort or pain. They were treated either with the alpha 2-agonist medetomidine at 40 micrograms/kg (15 intravenously and 17 intramuscularly), or 80 micrograms/kg (15 intravenously and 15 intramuscularly) or with xylazine plus l-methadone (1.0 mg)(10 intravenously). The levels of sedation, analgesia and safety were compared clinically and by measurements of the effects on the electrocardiogram (ECG) and blood gases, body temperature, haematology and clinical chemistry. Sedation was achieved reliably with both medetomidine and xylazine plus l-methadone but its onset, depth and duration were influenced by the dose and route of administration. In the medetomidine-treated dogs, intravenous administration resulted in more rapid sedation and the effects of the higher dose were deeper and longer lasting. The small dogs receiving 40 micrograms/kg may have been underdosed. The initial analgesic effects in response to a pin prick to the body surface were sufficient and similar for both drugs, except for the intramuscular dose of 40 micrograms/kg medetomidine. Analgesia for the clinical procedures was less reliable with medetomidine and was not always adequate even at the high dose, but xylazine plus l-methadone assured analgesia in almost every case. Medetomidine resulted in marked bradycardia, lasting as long as the sedation and the ECG revealed a sinus arrhythmia with sinoatrial and atrioventricular blocks grade I and II as a sign of interference with transduction. The bradycardia with xylazine plus l-methadone was less pronounced. A decrease in respiratory rate accompanying sedation had no influence on blood gases and blood acidity in the dogs treated with medetomidine but caused a respiratory acidosis with xylazine plus l-methadone. Body temperature decreased with all treatments for the duration of the period of sedation. Blood glucose concentration increased to a similar extent in all treatment groups, but all other haematological and clinicochemical variables remained unchanged. Treatment with the specific alpha 2 antagonist, atipamezole, reversed the sedation and cardiovascular and pulmonary effects due to medetomidine within minutes.
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PMID:Clinical comparison of medetomidine with xylazine/l-methadone in dogs. 865 Sep 15

The binding of acids and alkalis, formed in tissues by metabolism, along with oxygen and CO(2) transport are recognise as the principal functions of red blood cells (RBCs). Decreases in internal environment pH may result in activation of potential endogenous cytotoxic metabolites, OH and oxidant formation and, as a consequence, result in oxidative damage of cell membrane leading to hemolysis. The characteristics of acid hemolysis in hibernating mammals have been determined in this study. Parameters of HCl-hemolysis, such as the average time for RBC hemolysis and the population distribution of the response, have been investigated. Measurements were performed within 40-5 degrees C temperature range. The resistance of hibernator RBCs to increased acidity, determined according to the acid hemolysis parameters, was found to reflect whether the animal was in the summer active period or in hibernation, with differences also apparent at different points with the hibernation season itself. It was demonstrated that hemolysis parameters of naturally cold-tolerant organisms are altered by decreases in temperature. We discuss a role of cytoskeletal-membrane interactions as a fast-acting switch of the structural and functional state of hibernator RBCs as an adaptation mechanism to acidosis arising from hypothermia and hypermetabolism.
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PMID:Peculiarities of RBCs resistance to acid hemolysis in hibernating mammals. 1851 52

Despite the progressively increasing use of zebrafish (Danio rerio) in research, the most humane method of euthanasia for these fish has not been determined. Contemporary guidance documents state that hypothermia is an unacceptable method of euthanasia. The goal of this study was to compare rapid cooling and tricaine methanesulfonate (MS222) for zebrafish euthanasia. Zebrafish (n = 46) were euthanized by immersion in either an ice-water (4 degrees C or less) bath or unbuffered MS222 solution (250 mg/L; 25 to 30 degrees C). Another cohort (n = 10) was exposed to buffered MS222 to determine whether the acidity of the water alone caused distress. The times from exposure until the animals became unable to swim, right themselves, and death were measured, and signs of distress were recorded. Fish then were placed in a 'recovery tank' of system water to verify that recovery did not occur. Tissues were examined histologically. The mean time for euthanasia was longer and the number of fish exhibiting signs of distress was greater for fish exposed to MS222 than those exposed to chilled water. In addition, 4 of the 23 fish exposed to MS222 regained consciousness in the recovery tank, whereas none of 23 fish exposed to chilled water recovered. No histopathologic changes or evidence of ice crystal formation were seen in either group. In light of the faster time to death and fewer signs of distress in zebrafish euthanized by rapid cooling, we advocate this method as a humane veterinary practice.
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PMID:Evaluation of rapid cooling and tricaine methanesulfonate (MS222) as methods of euthanasia in zebrafish (Danio rerio). 1993 Aug 28

Tissue oxygenation, extracellular acidity, and tissue reducing capacity are among crucial parameters of tumor microenvironment (TME) of significant importance for tumor pathophysiology. In this paper, we demonstrate the complementary application of particulate lithium octa-n-butoxy-naphthalocyanine and soluble nitroxide paramagnetic probes for monitoring of these TME parameters using electron paramagnetic resonance (EPR) technique. Two different types of therapeutic interventions were studied: hypothermia and systemic administration of metabolically active drug. In summary, the results demonstrate the utility of EPR technique for non-invasive concurrent longitudinal monitoring of physiologically relevant chemical parameters of TME in mouse xenograft tumor models, including that under therapeutic intervention.
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PMID:Concurrent Longitudinal EPR Monitoring of Tissue Oxygenation, Acidosis, and Reducing Capacity in Mouse Xenograft Tumor Models. 2719 7

Organ injury during ischemia is one of the clinical problems of today's transplantation. It occurs during warm ischemia time (WIT) when the blood flow is cut off and during cold ischemia when a graft is chilled in situ until the circulation is restored to the recipient organism. Fast cooling of the organ slows down metabolism and activates intracellular enzymes, which minimizes the effects of warm ischemia. Unfortunately, hypothermia also results in inhibition of ATP synthesis, cell swelling and intracellular acidity. That is why research is continually being conducted to develop new fluids for rinsing and storing organs, as well as to optimize the composition of those that are already in use, which will allow for longer and more effective graft storage and restoration of their optimal functions after transplantation. This article provides current information on rinsing and storage fluids available on the global market. It also discusses tips for the fluid modifications with hormones and micronutrients.
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PMID:Tips for optimizing organ preservation solutions. 2935 49