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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The respiratory system, that is the set of compartments interposed between the cells and the environment, is best studied among mammals. Across the compartments there exist net fluxes of O2 and CO2, the intensities of which depend on the animal's size. In steady state, at rest, the relation between O2 flux and body size has the form of an allometric equation in which the O2 consumption, MO2, is proportional to body mass with an exponent or scaling factor of about 0.75 (Brody, 1945; Kleiber, 1961). The principal experimental methods to force animals to maximal MO2 are cold exposure and exercise. According to the concepts of physiological time, strenuous exercise to reach maximal MO2 should be shorter in small animals than in large ones. The scaling factor for maximal MO2 seems to be higher than standard conditions; in other terms, large exercising mammals may increase their maximal MO2 more than small animals. The comparative approach of maximal MO2 is a powerful tool for finding where in the respiratory system the strictures or bottlenecks are which may limit O2 consumption. According to the ambient or organismal conditions (pressure, temperature, posture, nutrition), the site of the stricture may vary. As far as is known, the O2 consumption of the whole human body, in standard conditions as well as in maximal activity, and for a given mass, is such that, compared to other mammals, the human exhibits no species-specific characteristics.
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PMID:Comparative aspects of maximal oxygen consumption. 221 97

In the present study we compared skin-ablative effects produced by 2.94-microns pulsed erbium-YAG radiation on pig skin with those of the pulsed 308-nm UV excimer laser, continuous-wave CO2 laser, electrocautery and cold-knife surgery. Pulsed 2.94-microns radiation led to clean ablation craters and precise cuts with only minimal adjacent tissue damage followed by excellent healing without apparent scarring. These experimental results are consistent with those obtained from first clinical applications in the treatment of epidermal naevi and tattoos. However, since coagulation was insufficient to prevent bleeding and because of low repetition rates provided, the Er-YAG lasers currently available seem as yet of limited value for effective removal of deeper or larger lesions.
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PMID:Pulsed 2.94-microns erbium-YAG laser skin ablation--experimental results and first clinical application. 222 47

Adult and aged male C57BL/6J mice were subjected to three consecutive 3-hour cold stress tests (partial physical restraint at 6 degrees C), repeated 2 weeks apart. Body mass and colonic temperature were measured before each test, and colonic temperature, O2 consumption, and CO2 production were measured during cold exposure. The slopes of colonic temperature and heat production and the mean metabolic heat production were calculated for each animal. Adult mice showed stronger cold tolerance compared to aged mice and also exhibited habituation to cold exposure (improvement of cold tolerance with repeated tests). Mean metabolic heat production during cold exposure was greater in adult mice, and only adults demonstrated significant increases across tests in both metabolic heat production and slope of metabolic heat production over time. We hypothesize that reduced cold tolerance in aged mice is related mainly to a decrease in metabolic heat production. Increased metabolic heat production in subsequent tests in adults is a probable mechanism for habituation to repeated cold exposure.
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PMID:Metabolic heat production during repeated cold stress in adult and aged male C57BL/6J mice. 222 39

Adult (9-14 month) and aged (29-31 month) male C57BL/6J mice were subjected to 3 baseline tests (BASE), 3 cold tests (COLD), or 3 baseline immediately followed by cold tests (BASE/COLD). All tests consisted of partial restraint, and baseline tests were at 24 degrees C for 1 h while cold tests were at 6 degrees C for 3 h. All tests were started at 0900 and were repeated every 2 weeks. Mice were weighed before each test and colonic temperature, O2 consumption, and CO2 production were measured every 4 min for the duration of the test. Mean metabolic heat production during baseline and/or cold and slopes of colonic temperature over time during cold were calculated for each animal. Metabolic heat production at 24 degrees C in both BASE and BASE/COLD was the same in aged mice as adults, however, at degrees C BASE/COLD adult mice increased metabolic heat production compared to 24 degrees C, while aged mice produced a similar amount of heat at both 6 degrees C and 24 degrees C. When comparing metabolic heat production at 6 degrees C between COLD and BASE/COLD mice, adult COLD mice demonstrate an habituation to repeated cold exposure accompanied by increasing heat production, while BASE/COLD adults produce higher heat in all 3 cold exposures. The authors suggest that this is due to a priming of heat production in adults by restraint before the cold. In aged mice, neither COLD nor BASE/COLD groups demonstrate habituation, but BASE/COLD mice produce more heat than COLD during cold exposure, again indicating baseline priming of heat production. The data imply that aged mice have an impairment in specific cold-induced thermogenesis, while their abilities to produce heat in response to restraint-induced sympathetic activation remains intact.
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PMID:Metabolic heat production during repeated testing at 24 degrees C and 6 degrees C in adult and aged male C57BL/6J mice: the effect of physical restraint before cold stress. 225 92

In the present study the functional and morphologic effects of two pulmoplegic solutions are evaluated. Single left-lung allotransplantation with ligation of the right pulmonary artery was performed in 15 piglets (13-20 kg). The lungs were preserved after donor prostaglandin E-1 treatment with single pulmonary artery flush with either modified Euro-Collins solution (mECS) (9 pigs) or oxygenated fluorocarbon emulsion (FC-43) (6 pigs) and transplanted after 6-hr storage in cold Physiosol solution. Tidal volumes of 15 ml/kg x fr (18) with 40% inspired oxygen were used for ventilation during reperfusion. Function of the transplanted lung was monitored for 4 hr postoperatively by determining pa CO2 and pa O2 levels from arterial samples and by noninvasive monitoring of end-tidal CO2 values and arterial oxygen saturations. Sequential morphologic changes in pulmonary artery flow surface and lung tissue were studied after 6-hr storage and 4-hr reperfusion, using light, scanning, and transmission electron microscopy (LM, SEM, TEM). There was no mortality. After transplantation the mECS group experienced significant hypoxia and hypercarbia and had low end-tidal CO2 values as signs of defective oxygenation and gas exchange, whereas the FC-43 group was normoxic and normoventilated without disturbed elimination of carbon dioxide. After storage and reperfusion, LM showed signs of increased vascular permeability and reperfusion damage--more evident in the mECS group compared with the FC-43 group--while the lymphoid cell population was more intensely activated in the latter group. Electron microscopy after storage showed good overall preservation of structures in both groups. After reperfusion preservation of pulmonary artery flow surface and lung tissue was estimated to be moderate in the mECS group, whereas it was good-to-moderate in the FC-43 group by SEM (NS). TEM of lung tissue, however, showed significantly better-preserved alveolar epithelial lining in the FC-43 group compared with the mECS group. In conclusion, oxygenated fluorocarbon (FC-43) pulmoplegia gave better functional and morphologic preservation of lung grafts compared with modified Euro-Collins solution.
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PMID:Single lung allotransplantation in pigs. A morphologic study of tissue preservation with modified Euro-Collins and fluorocarbon solutions. 236 Feb 50

When mouse epididymal spermatozoa were rapidly frozen in two steps (37 to -70 degrees C for solid CO2 and -70 to -196 degrees C for liquid nitrogen) as pellets, 18% raffinose provided the greatest protection to ICR mouse spermatozoa against cold-shock; sperm motility and fertilizing ability were 43% and 22.4%, respectively. A small proportion of spermatozoa frozen with 10% sucrose was motile but incapable of fertilizing ovulated oocytes. Glycerol and dimethylsulphoxide were less effective at any concentration examined. However, the fertilizing ability of frozen-thawed ICR spermatozoa was significantly improved (35.5%) by addition of glycerol (1.75% final concentration) to medium containing 18% raffinose. Spermatozoa from one outbred (ddY) and 5 inbred (C57BL/6N, C3H/HeN, DBA/2N, BALB/c and kk) strains of mice were successfully frozen in the presence of 18% raffinose and 1.75% glycerol, although the fertilization rates of frozen-thawed spermatozoa varied among strains (13% for C57BL/6N to 64% for DBA/2N). A small fraction of mouse eggs resulting from fertilization by frozen-thawed spermatozoa developed normally in vitro (37% in C57BL/6N to 71% in ICR) to the blastocyst stage and in vivo (19% for C57BL/6N spermatozoa and ddY oocytes) to Day 18 of gestation.
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PMID:Cryopreservation of mouse spermatozoa in the presence of raffinose and glycerol. 240 78

O2 consumption and CO2 production were measured in lean and obese Zucker rats under these conditions: thermal neutrality (acclimation and test at 25 degrees C), acute cold (acclimation to 25 degrees C and test at 15 degrees C), and chronic cold (acclimation and test at 15 degrees C). The respiratory quotient (RQ) of ad libitum-fed animals was 0.92 at neutrality, 0.87 at acute cold, and 0.77 at chronic cold. Lean and obese animals had comparable RQs under the three conditions. These results confirm previous investigations on the effect of ambient temperature on gaseous exchange in rats but fail to demonstrate a difference in substrate utilization in the metabolism of lean and obese Zucker rats.
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PMID:Effect of ambient temperature on respiratory quotient of lean and obese Zucker rats. 249 61

We present a case of erythroplasia of Queyrat in a 77-year-old man involving the distal two-thirds of the penis. There was no urethral or periurethral involvement. Due to the location of the lesion, its recognition as carcinoma in situ, and the technical difficulty of cold-steel excision in this area, we used the carbon dioxide (CO2) laser to selectively destroy the tumor. In this case the laser provided controllable tissue destruction, ease of surgery, and excellent cosmesis.
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PMID:Carbon dioxide laser treatment of erythroplasia of Queyrat. 234 65

Intraoperative and postoperative complications related to CO2 laser conization and cold knife conization were compared. From 1980 to 1984 66 patients were hospitalized for cold knife conization, the mean operative time was 28.1 minutes, all patients had epidural anesthesia, and the mean time of admission was 6.8 days. Three percent of cases had infections, the mean intraoperative hemorrhage was 75 ml, and the rate of remaining foci of neoplasia was 18.2%. Meanwhile there were 116 patients hospitalized for CO2 laser conization from 1985 to 1987. The mean operative time was 15.6 minutes, 15.5% of cases had local anesthesia, the mean time of admission was 0.6 days. Zero percent of cases had infections, 0% of cases had postoperative cervical stenosis, the mean intraoperative hemorrhage was 75 ml, and 29.5% of cases had remaining foci of neoplasia. There was no significant difference in hemorrhage amounts at hysterectomy following conization either method. Thus, in our experience, CO2 laser conization is more effective for clinical diagnosis and treating of cervical intraepithelial neoplasia.
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PMID:[A comparison between CO2 laser conization and cold knife conization in clinical diagnosis of cervical intraepithelial neoplasia]. 251 61

Constant infusions of cold molar lactate (178.0 +/- 1.6 mumol.kg-1.min-1), [U-14C]lactate (0.50 muCi/min), and [6-3H]glucose (0.5 muCi/min) were employed to study the effects of endurance training (running 1 h/day, at 38 m/min, 10% grade) on lactate clearance in resting, hyperlactatemic rats. Before infusion, resting blood lactate levels were not significantly different between controls, 1.10 +/- 0.04 mM, and trained animals, 1.16 +/- 0.04 mM. Lactate levels increased significantly during the infusion period, attaining steady-state mixed venous concentrations of 11.32 +/- 0.24 mM and 5.44 +/- 0.09 mM, respectively, for controls and trained animals. Lactate clearance rates, based on net lactate removal (i.e., not tracer-estimated lactate removal), were twofold greater in trained animals vs. controls, 33.0 +/- 0.7 and 15.4 +/- 0.4 ml.kg-1. min-1, respectively. Lactate specific activity values during the infusion period were not significantly different between controls, 22,243 +/- 236 dpm/mumol, and trained animals, 21,270 +/- 374 dpm/mumol, indicating similar endogenous dilution of the pyruvate-lactate pool. For both control and trained animals, essentially 100% of the 14C infused as lactate was recovered as either glucose or CO2; however, trained animals demonstrated a 25% greater rate of gluconeogenesis. At a given lactate production rate, trained animals maintain lower lactate levels through enhanced clearance via gluconeogenesis and oxidation.
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PMID:Endurance training enhances lactate clearance during hyperlactatemia. 251 15


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