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

An operative repair technique for crushed sciatic nerve in the rat was used to examine whether removal of the damaged tissue could be better achieved with a low wattage CO2 laser or a blade. This approach was compared to results in rats undergoing conventional end-to-end nerve anastomosis using a microsurgical approach. Crushed sciatic nerves were exposed bilaterally 24 hours after injury and treated as follows. A longitudinally split polyethylene catheter was placed under the nerve, which was fixed to the catheter with 9-0 stitches placed away from lesion area; the nerve was bathed in ice-cold polyvinyl alcohol/chlorpromazine (PVA/CPZ) solution. After the nerve was crushed, the lesioned tissue was removed using laser pulses or a thin blade. A collagen matrix was used to fill the gap, and the preparation was covered and allowed to recover for 6 weeks. End-to-end anastomosis was done following same parameters, but with omission of the nerve catheter, PVA/CPZ solution, and collagen matrix; these nerves were reunited using epineurial stitches. High performance liquid chromotography (HPLC) analysis of each group showed that the laser approach reduced the levels of norepinephrine distal to the lesion, least, suggesting better regeneration of proximal axonal growth. Morphological and neuroelectric findings, although suggestive, showed no significant differences between laser and blade repair, a finding that reinforces the idea that such endpoints are not as sensitive as chemical assays of tissue transmitter levels such as HPLC. Laser or blade repair using nerve-catheter fixation and collagen bridge matrix was superior to end-to-end nerve anastomosis when morphological, neuroelectric, and HPLC values were compared in this model.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Laser or razor? A novel experimental peripheral nerve repair technique. 336 20

Oxygen consumption, (VO2), carbon dioxide production (VCO2) and ventilation were measured in little penguins (Eudyptula minor) in air and water over a range of ambient temperatures. Barometrically measured minimum ventilation was very low (112 +/- 23 ml.min-1 over the range 15-20 degrees C, n = 9), principally due to a lower than predicted respiratory frequency (f) (6.9 +/- 1.1 min-1). This low ventilation resulted in a very high oxygen extraction (EO2) and low air convection requirement (VI/VO2). Despite large increases in metabolic rate in birds in cold water, VI/VO2 and hence EO2 did not vary in non-heat exposed penguins over a range of air and water temperatures. Mean extraction was 53.2 +/- 10.8% (n = 82) corresponding to an air convection requirement of 11.3 +/- 2.5 L.L-1. Above thermoneutrality there was a dramatic increase in ventilation and fall in EO2 resulting from increases in both f and tidal volume (VT). End-expired gases were measured at thermoneutrality and during heat exposure. At thermoneutrality FE'CO2 was 0.074 +/- 0.005, and FE'O2 0.115 +/- 0.009. During heat exposure end expired gases approached atmospheric levels.
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PMID:Ventilation and oxygen extraction in the little penguin (Eudyptula minor), at different temperatures in air and water. 337 8

Vero cells, SP2/O-Ag 14 myeloma cells and 4B87 hybridoma cells were stored either at refrigeration (5 degrees C) or freezing (-18 degrees C) temperatures. Cells were recovered every five days and percentages of viable cells were determined by the trypan blue exclusion staining method before the cells were incubated at 37 degrees C in a 5% CO2 atmosphere. SP2/0 cells grew after 30 days of storage at 5 degrees C. Hybridoma (4B87) cells survived 20 days of cold storage in HY medium and maintained antibody production. For each cell type, higher percentages of viable cells were observed among cells stored in HY medium than among cells stored in DMEM. Vero cells stored for 40 days at 5 degrees C grew when removed to optimal conditions of 37 degrees C and 5% CO2. There was no growth of cells recovered after storage at -18 degrees C.
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PMID:Survival of Vero, myeloma and hybridoma cells during cold storage. 340 8

When cells in culture are released from G0 into cycle by diluting into fresh medium there is a delay of many hours before they re-enter the cycle and start DNA synthesis. A mouse melanoma cell line designated HP2 has been used to investigate the effects of non-standard temperatures between the time of plating and DNA synthesis. When the cells were incubated in a 5% CO2 box at 8 degrees C for periods during the G0-G1 transition there was an extra delay before the start of S, approximately equal to the time that the cells were held at 8 degrees C and independent of the time when the cold pulse was administered. When the cells were cooled to 25 degrees C the delay was longer than the time for which the cells had been kept at 25 degrees C, and this extra delay was also dependent on the point in G0-G1 when the cells were cooled, as though the cells could be reset to an earlier time by this treatment. It is suggested that a labile substance required for progression is destroyed faster than it is made at 25 degrees C but at 8 degrees C the rate of destruction is very low. Another phenomenon noted during these cooling experiments was that the peak height of the S phase profile, as measured by frequent pulse-thymidine incorporation experiments, was substantially higher for cells which had been cooled at a later stage in the G0-G1 transition, even though the overall times at 37 degrees C and at the colder temperature were identical. By varying the temperature of the cold pulse it was possible to separate the change in the peak height and the delay as separate entities.
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PMID:Cycle reset in a melanoma cell line caused by cooling. 350 29

Intranasal infection of mice with a sublethal dose of Bordetella pertussis produced hypoglycaemia and hyperinsulinaemia. Exposure to ether vapour did not modify serum insulin concentrations in control mice, but produced a marked transient hyperinsulinaemia in mice infected with B. pertussis. A similar hyperinsulinaemia in infected, but not control, mice was also seen after a brief (10-15 s) period of anoxia (produced by exposure to an atmosphere of 100% N2 or 100% CO2), or following the injection of histamine or 2-deoxyglucose. Exposure to cold (2-4 degrees C) or hypoxia (8% O2 in 92% N2), however, did not alter serum concentrations of insulin in control or infected mice. The hyperinsulinaemic response to ether stress observed in mice infected with B. pertussis was abolished by pretreatment with alloxan. The hyperglycaemic effects of histamine and 2-deoxyglucose were attenuated or abolished in mice infected with B. pertussis. However, none of the stimuli which produced hyperinsulinaemia in the infected mice resulted in any further lowering of the blood glucose concentration. Pretreatment of mice with pertussis toxin (150 ng/mouse, i.v.) produced hypoglycaemia similar in magnitude to that found in animals infected with B. pertussis. Moreover, exposure of mice treated with pertussis toxin to ether vapour produced marked hyperinsulinaemia. It is suggested that the metabolic alterations seen in animals infected with B. pertussis may be mediated by pertussis toxin.
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PMID:Hypoglycaemia and acute stress-induced hyperinsulinaemia in mice infected with Bordetella pertussis or treated with pertussis toxin. 354 69

Twenty-six healthy mixed-breed dogs (25 to 35 kg) underwent hypothermic (27 C) cardiopulmonary bypass. The heart was arrested with cold (4 C) cardioplegic solution, and left ventriculostomy performed. Postoperative mortality was 11.5% (3/26). Two deaths were attributable to ventricular fibrillation the night after surgery, and one death 2 weeks later was the result of pulmonary embolization. All other dogs recovered promptly and were well at follow-up evaluation 6 weeks later. The most important considerations were (1) the surgical approach, ie, combining left lateral thoracotomy with cannulation of the right atrium and left femoral artery for cardiopulmonary bypass (CPB) (avoiding median sternotomy and aortic arch perfusion), (2) the adherence to strict criteria for CPB perfusion, consisting of blood flow of at least 2.2 L/m2/min, PCV no less than 25%, gas flow through the oxygenator (97% O2, 3% CO2) of at least 3.5 L/min, maintenance of a mean arterial blood pressure greater than 60 mm of Hg, and heparinization to maintain activated clotting time over 480 seconds, (3) the use of dipyridamole infusion to preserve platelets during CPB, resulting in decreased postoperative blood loss and (4) the monitoring of cardiac, respiratory, renal, and neurologic functions before, during, and after the operation, with particular emphasis on fluid balance and electrolytes. We concluded that a high success rate is possible for open-heart surgery in the dog requiring cardiopulmonary bypass, but only through meticulous surgical technique and the combined application of many monitoring techniques, with timely intervention to correct serious departures from homeostasis.
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PMID:Technique and postoperative management for successful cardiopulmonary bypass and open-heart surgery in dogs. 357 Sep 42

A thermal clearance technique for measuring cerebral blood flow is described and compared with the radiolabelled microsphere technique. The thermal technique involves measurement of the rewarming curve generated after bolus infusion of 4-5 ml of ice-cold saline into the common carotid artery with a subdural thermistor placed on the parietal cortex. Evaluation of the biexponential decay curves obtained with this technique demonstrated a close correlation with total hemispheric, parietal, and parietal gray blood flow determined by simultaneous microsphere measurement. Despite significant correlations (p less than 0.001), scatter in the data produced a broad 95% confidence interval, thus making interpretation of blood flow with the thermal clearance technique impossible. Furthermore, instrumentation with the thermal probe, which required opening of the dura, blunted the cerebral blood flow response to hypercapnia. We conclude that the major limitations of the thermal clearance technique include: nonhomogeneous clearance function, significant variability, and depression of CO2 reactivity. These limitations must be addressed before this technique can be used reliably in the laboratory.
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PMID:Comparison of thermal clearance measurement of regional cerebral blood flow with radiolabelled microspheres. 359 Feb 53

Upper airway exposure to cigarette smoke elicits reflex changes in breathing pattern. To examine whether laryngeal afferents are affected by cigarette smoke, neural activity was recorded from the peripheral cut end of superior laryngeal nerve in anesthetized dogs. A box-balloon system, connected to the breathing circuit, allowed smoke to be inhaled spontaneously through the isolated upper airway while preserving its normal respiratory flow and pressure. Our results showed the following. Inhalation of cigarette smoke (25-50% concentration, 300-400 ml) caused a marked increase in activity of laryngeal irritant receptors which were either silent or randomly discharging during control breathing [their activity increased from a control value of 1.67 +/- 0.50 (mean +/- SE; n = 21) to a peak of 5.03 +/- 0.85 impulses/s in 11-15 s]. The activity of laryngeal cold receptors was reduced to 77.3 and 63.8% of control (n = 9) during the two breaths of smoke inhalation, respectively. After returning toward the base-line activity, a more pronounced inhibition (26.3% of control) occurred at three to nine breaths after the smoke inhalation. A small but significant decrease (88.5% of control) in the inspiratory discharge of laryngeal mechanoreceptors was observed during the first test breath. These effects were independent of the CO2 content of the smoke. Furthermore, there was no difference between the responses of these laryngeal afferents to high- and low-nicotine cigarette smoke.
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PMID:Acute effect of cigarette smoke on laryngeal receptors. 359 27

Experiments were carried out on conscious cats to evaluate the general characteristics and modes of action of hypoxia on thermoregulation during cold stress. Intact and carotid-denervated (CD) conscious cats were exposed to ambient hypoxia (low inspired O2 fraction) or CO hypoxia in prevailing laboratory (23-25 degrees C) or cold (5-8 degrees C) environments. In the cold, both groups promptly decreased shivering and body temperature when exposed to either type of hypoxia. Small increases in CO2 concentration reinstituted shivering in both groups. At the same inspired concentration of O2, CD animals decreased shivering and body temperature more than intact cats. While this difference resulted, in part, from a lower alveolar PO2 in CD cats, a difference between intact and CD cats was apparent when the two groups were compared at the same alveolar PO2. During more prolonged hypoxia (45 min), shivering returned but did not reach normoxic levels, and body temperature tended to stabilize at a hypothermic value. Exposure to various levels of hypoxia produced graded suppression of shivering, with the result that the change in body temperature varied directly with inspired O2 concentration. Hypoxia appears to act on the central nervous system to suppress shivering and sinus nerve afferents appear to counteract this direct effect of hypoxia. In intact cats, this counteraction appears to be sufficient to maintain body temperature under hypoxic conditions at room temperature but not in the cold.
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PMID:Hypoxia-induced changes in shivering and body temperature. 361 Sep 40

Molluscum contagiosum is an infectious disease of the skin, found primarily on the thighs and genitalia. It is a sexually transmitted disease of increasing prevalence. The traditional treatment of this condition is surgical ablation, although CO2 laser has been advocated recently as an alternative mode of therapy. Six patients with molluscum contagiosum were treated by either continuous or intermittent CO2 laser. Four of the six have developed severe keloid scars. Removal of lesions by cold knife, however, was not followed by keloid scars. In the same patient, areas affected by human papillomavirus that were treated with CO2 laser did not develop keloid scars. Our results question the use of CO2 laser therapy for molluscum contagiosum.
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PMID:Keloid scars as a result of CO2 laser for molluscum contagiosum. 362 87


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