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Results for “Cold Temperature”

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PubMed2001

Acute cold exposure induces vagally mediated Fos expression in gastric myenteric neurons in conscious rats.

Acute cold exposure-induced activation of gastric myenteric neurons in conscious rats was examined on longitudinal muscle-myenteric plexus whole mount preparations. Few Fos-immunoreactive (IR) cells (<1/ganglion) were observed in 24-h fasted rats semirestrained at room temperature. Cold exposure (4 degrees C) for 1-3 h induced a time-related increase of Fos-IR cells in corpus and antral myenteric ganglia with a maximal plateau response (17 +/- 3 and 18 +/- 3 cells/ganglion, respectively) occurring at 2 h. Gastric vagotomy partly prevented, whereas bilateral cervical vagotomy completely abolished, Fos expression in the myenteric cells induced by cold exposure (2 h). Hexamethonium (20 mg/kg) also prevented 3-h cold exposure-induced myenteric Fos expression by 76-80%, whereas atropine or bretylium had no effect. Double labeling revealed that cold (3 h)-induced Fos-IR myenteric cells were mainly neurons, including a substantial number of choline acetyltransferase-containing neurons and most NADPH-diaphorase-positive neurons. These results indicate that acute cold exposure activates cholinergic as well as nitrergic neurons in the gastric myenteric ganglia through vagal nicotinic pathways in conscious rats.

Animals↗

PubMed2006

Change in Ucp1 mRNA expression following long-term cold exposure under normal or high-fat diet regimes in the cold-intolerant mammal, Suncus murinus.

The house musk shrew (Suncus murinus), or suncus, is a unique experimental mammal that is cold intolerant. However, even basic knowledge of brown adipose tissue (BAT), which is important for non-shivering thermogenesis (NST), is minimal. Therefore, we exposed suncus for 18 days to mild cold temperatures (8-14 degrees C) and/or a high-fat diet, which are factors that increase NST, and measured two mRNAs that are critical for NST in BAT, uncoupling protein 1 (Ucp1) and type II 5'-deiodinase (D2). Neither mild cold exposure nor a high-fat diet alone induced up-regulation of the mRNAs. However, combinations of cold exposure and high-fat diet significantly increased both mRNAs. Therefore, cold intolerance in suncus may be partly caused by dietary components.

Adaptation, Physiological↗

PubMed1981

Histological effects and lead concentrations in tissues of adult male ringed turtle doves that ingested lead shot.

Adult male ringed turtle doves (Streptopelia risoria) were administered 0 or 4-110 mg lead shot and/or were exposed to cold temperatures (6 +/- 1 degrees C). Five of the seven doves that ingested shot and were exposed to cold died. Doves that ingested shot and were not exposed to cld (21 +/- 1 degrees C) had no mortality after 9 d, but several birds had seizures. Tissues were examined microscopically for lesion. Doves ingesting shot consistently had Pb intranuclear inclusion bodies in cells of the proximal convoluted tubules, except if death occurred 48 h after shot ingestion. In such cases as in cold-exposed, Pb-treated birds), intracytoplasmic inclusions were detected. Hemosiderin loading in kupffer cells and rarely in hepatocytes was observed in doves ingesting Pb whether they were exposed to a normal temperature or to cold. it appeared that ingestion of shot could abruptly disturb spermatogenesis in ringed turtle doves. The seminiferious tubules were often devoid of spermatozoa in doves ingesting Pb.

Animals↗

PubMed2005

Effects of chronic cold exposure on the endothelin system.

Cold temperatures have adverse effects on the human cardiovascular system. Endothelin (ET)-1 is a potent vasoconstrictor. We hypothesized that cold exposure increases ET-1 production and upregulates ET type A (ETA) receptors. The aim of this study was to determine the effect of cold exposure on regulation of the ET system. Four groups of rats (6-7 rats/group) were used: three groups were exposed to moderate cold (6.7 +/- 2 degrees C) for 1, 3, and 5 wk, respectively, and the remaining group was maintained at room temperature (25 degrees C) and served as control. Cold exposure significantly increased ET-1 levels in the heart, mesenteric arteries, renal cortex, and renal medulla. Cold exposure increased ETA receptor protein expression in the heart and renal cortex. ET type B (ETB) receptor expression, however, was decreased significantly in the heart and renal medulla of cold-exposed rats. Cold exposure significantly increased the ratio of ETA to ETB receptors in the heart. An additional four groups of rats (3 rats/group) were used to localize changes in ETA and ETB receptors at 1, 3, and 5 wk of cold exposure. Immunohistochemical analysis showed an increase in ETA, but a decrease in ETB, receptor immunoreactivity in cardiomyocytes of cold-exposed rats. Increased ETA receptor immunoreactivity was also found in vascular smooth muscle cells of cold-exposed rats. Cold exposure increased ETA receptor immunoreactivity in tubule epithelial cells in the renal cortex but decreased ETB receptor immunoreactivity in tubule epithelial cells in the renal medulla. Therefore, cold exposure increased ET-1 production, upregulated ETA receptors, and downregulated ETB receptors.

Animals↗

PubMed1997

Differentiation between cold shock proteins and cold acclimation proteins in a mesophilic gram-positive bacterium, Enterococcus faecalis JH2-2.

Transfer of Enterococcus faecalis to a cold temperature (8 degrees C for 4 to 30 h) led to increased expression of 11 cold shock proteins (CSPs). Furthermore, this mesophilic prokaryote synthesized 10 cold acclimation proteins, five of them distinct from CSPs, during continuous growth (4 days) at the same temperature (8 degrees C).

Bacterial Proteins↗

PubMed1997

Improved ultrastructural preservation of bioprosthetic tissue.

BACKGROUND AND AIMS OF THE STUDY: Poor ultrastructural tissue preservation of bioprosthetic heart valves is associated with a higher propensity for calcification. In spite of this realization, commercial valve fixation remains suboptimal. METHODS: In an attempt to maintain tissue integrity through improved cross-linking procedures, transmission electron microscopy and a 21-point damage score were applied to assess the ultrastructural preservation of aortic wall tissue-the main component of contemporary aortic valve bioprostheses. An ideal glutaraldehyde (GA) concentration was assessed by immediate tissue fixation at 4 degrees C comparing 0.2%, 0.5%, 0.65%, 1.0%, 2.0%, 3.0% and 4.0% GA in phosphate-buffered saline (PBS). Subsequently, an optimal concentration of 3.0% GA was used to determine the effect of fixation temperature (4 degrees, 22 degrees and 37 degrees C). Finally, the superior glutaraldehyde concentration (3.0%) and cross-linking temperature (4 degrees C) were used to assess tolerance towards delayed fixation. RESULTS: When different GA concentrations were used almost identical damage scores of 6.3 and 5.8 were found for 0.2% and 0.65% fixation. The first significant improvement was found at a concentration of 1.0% (score 3.3; p < 0.01) followed by a further improvement at 3.0% (score 2.6; p = 0.05). The optimal fixation temperature was 4 degrees C (3.7) with the worst results obtained at room temperature (score 9.2; p < 0.03). When fixation was delayed, the most significant damage occurred during the initial 30 min after slaughter (from 2.3 to 7.4; p < 0.02) followed by another significant deterioration between 4 and 16 h (from 5.6 to 9.7; p < 0.02). CONCLUSIONS: In summary, the prerequisites for an ideal ultrastructural preservation of bioprosthetic aortic wall tissue are immediate fixation (within 30 min), high GA concentrations (> 1.0%) and cold-temperature fixation (4 degrees C).

Animals↗

PubMed1976

Effect of chilling on the survival of Bacteroides fragilis.

Factors affecting the susceptibility of Bacteroides fragilis subsp. fragilis to low temperature were examined. Predetermined numbers of cells were spread on agar media or suspended in enriched Trypticase soy broth and exposed to low temperature under both aerobic and anaerobic conditions. Exposure of 18-h growth of a freshly isolated B. fragilis strain to 4 degrees C aerobically or anaerobically resulted in a loss of at least 50% viability after 12 h. B. fragilis cells in early growth (6 h) were more tolerant to exposure at 4 degrees C than older cells (18 h). When the freshly isolated strain was repeatedly subcultured in the laboratory it was uniformly more cold tolerant than fresh clinical isolates. The incorporation of 1.0 M sucrose and 5 mM magnesium chloride into liquid media partially alleviated the lethal effects of cold temperature on B. fragilis subsp. fragilis.

Aerobiosis↗

PubMed2003

Skin temperature recovery from cold provocation in workers exposed to vibration: a longitudinal study.

BACKGROUND: Vibration white finger (VWF) is characterised by arterial hyperresponsiveness and vasoconstriction following cold provocation. Several years after of removal from exposure, most subjects show improved finger systolic blood pressure (FSBP) under conditions of cold challenge, but continue to report cold hands and finger blanching. AIMS: To assess the underlying reasons for the persistence of cold symptoms. METHODS: A total of 204 former users of pneumatic tools with cold related hand symptoms were evaluated and then re-evaluated a year later. Symptoms were evaluated using the Stockholm Workshop Scale. Finger systolic blood pressure per cent (FSBP%) was assessed by comparing digital blood pressure in a cold provoked and normalised state. Fingertip skin temperature was measured during cooling and occlusion and during rewarming and recovery. RESULTS: There were dramatic improvements in FSBP% (14.3 mm Hg %), modest improvement in recovered skin temperature (0.86 degrees C), and no change in symptom stage. When the most symptomatic subjects (n = 75) were compared with the less symptomatic subjects (n = 129), there were similar inter-test improvements in FSBP%. Skin temperature recovery improved in the less symptomatic (+1.49 degrees C), but did not change in the most symptomatic group (-0.12 degrees C). However, the more symptomatic group had higher temperatures at the initial test, thus qualifying the result. CONCLUSIONS: Skin temperature recovery after cold challenge in subjects with VWF remains reduced in the symptomatic subjects several years after exposure removal. This is evident even when blood pressure has increased in the setting of cold provocation. Results suggest that in VWF, the dermal circulation remains impaired, even after the restoration of arterial blood pressure in the digits.

Adult↗

PubMed1991

Transient corneal opacification induced by cold in Raynaud's disease.

A 48-year-old man presented with longstanding complaints of transient blurring of vision on exposure to cold temperatures. A review of family history was noteworthy in that two of the patient's four sons and the patient's brother had similar complaints. All affected individuals had Raynaud's disease. Results of ophthalmic evaluation showed transient corneal opacities. Slit-lamp video photography under cold stress demonstrated conjunctival vascular changes consistent with Raynaud's phenomenon. An extensive work-up for systemic disease was otherwise negative. To the best of the authors' knowledge, anterior segment changes have not been described previously in idiopathic Raynaud's disease.

Adolescent↗

PubMed1988

Low temperature storage and pupal survival in the Simulium damnosum complex.

Pupae of the Simulium damnosum complex were exposed for different time periods to temperatures of 0, 4, 8 and 12 degrees C before returning to ambient temperature (24-28 degrees C). As the period of exposure to the low temperatures increased, pupal survival decreased. A one day exposure even to 0 degrees C had little effect on survival, whereas for a 4 day exposure, the optimum survival occurred at 8 degrees C with a total of 46% emergence. Young pupae (pale cuticle) had greatest emergence after exposure to 12 degrees C, the old ones (dark sclerotised cuticle) after exposure to 8 degrees C. Exposure to the different cold temperatures did not significantly affect the longevity of the emerging adults. Low temperature storage of pupae is thus a viable method for long distance transportation of living specimens of blackflies.

Animals↗

PubMed1982

Protection against mercuric chloride nephrotoxicity by cold exposure in rats.

The influence of cold exposure (+ 1 degree C for 24 h) was studied in rats dosed i.p. with 0, 2.5 or 5.0 mumol HgCl2/kg. Cold exposure of controls caused an increased diuresis and solute elimination, except sodium, with almost no variations in urine alkaline phosphatase (ALP) and gammaglutamyl transferase (GGT). Proximal tubule brush border damage was demonstrated by a marked increase in ALP and GGT in HgCl2-dose animals at room temperature. Cold exposure protected against this kidney damage.

Animals↗

PubMed1983

Purification and characterization of sheep brain cold-stable microtubules.

The isolation of cold-stable microtubules in high yields, described previously only from rodents, was extended to the brain of higher animals. Under optimal conditions, yields of 30 mg of cold-stable microtubles per 100 g of sheep brain could be obtained routinely. Material purified by two polymerization cycles displayed the same stability to cold temperature or to millimolar concentrations of calcium and the same lability to calmodulin and to ATP as did the purified material obtained from the rat [Job, D., Rauch, C.T., Fischer, E.H. & Margolis, R.L. (1982) Biochemistry 21, 509]. Furthermore, DE-52 chromatography of this material yielded a fraction that restored cold stability when added to cold-labile microtubules. Known to bind to calmodulin and to enhance microtubule assembly, tau proteins had no cold-stabilizing activity. Protein profiles of the cold-stabilizing fraction from sheep and rat brain were similar to one another but showed no protein bands corresponding to the tau proteins.

Animals↗

PubMed2005

Complexity of the cold acclimation response in Drosophila melanogaster.

Insects can increase their resistance to cold stress when they are exposed to non-lethal conditions prior to the stress; these plastic responses are normally described only in terms of immediate effects on mortality. Here we examine in Drosophila melanogaster the short- and longer-term effects of different conditions on several measures of cold resistance, but particularly chill coma recovery. Short-term exposure to sublethal temperature (cold hardening) did not decrease chill coma recovery times even though it decreased mortality. Exposure to 12 degrees C for 2 days (acclimation) decreased chill coma recovery times for a range of stressful temperatures when flies were cultured at 25 degrees C, but did not usually affect recovery times when flies were cultured at 19 degrees C. In contrast, 2-day exposure to 12 degrees C decreased mortality regardless of rearing temperature. Rearing at 19 degrees C decreased mortality and chill coma recovery time relative to rearing at 25 degrees C. Acclimation increased the eclosion rate of eggs from stressed females, but did not affect development time or size of the offspring. These results indicate that plastic responses to cold in D. melanogaster are complex when resistance is scored in different ways, and that effects can extend across generations.

Acclimatization↗

PubMed1999

Cold acclimation-induced increase of systolic blood pressure in rats is associated with volume expansion.

To investigate the mechanisms of cold-induced hypertension, the systolic blood pressure (SBP) and average daily water consumption were measured weekly in 6-month-old male Wistar rats; they were subsequently acclimated to thermoneutrality (26 degrees C for 7 weeks), to cold temperature (6 degrees C for 9 weeks), and then again reacclimated to 26 degrees C for 5 weeks. Circulating plasma volume and whole blood viscosity were measured in subgroups of rats at the end of acclimation to 26 degrees C after 2 days, after 1, 6, and 8 weeks of cold, and after 2 and 5 weeks of rewarming. The control values obtained at the end of thermoneutral period were: SBP = 130.8 +/- 18.6 mm Hg, plasma volume = 41.9 +/- 4.64 mL/kg, whole body viscosity at shear rate of 22.5 per sec = 6.7 +/- 0.48 cps, and daily water consumption = 42.25 +/- 16.81 mL. After 48 h of cold exposure there was almost a 50% increase in plasma volume that persisted to a lesser degree throughout the whole period of cold exposure (P < .05). After 2 weeks of cold exposure the daily water consumption increased and SBP began to increase. After 6 weeks of cold exposure the SBP was 30 mm Hg above that of the control level (P < .001) and was accompanied by a 25% increase in whole blood viscosity (P < .05). At the end of 8 weeks of cold exposure the plasma volume was 56.8 +/- 9.51 mL/ kg and the whole blood viscosity was 8.0 +/- 1.79 cps at the 22.5 per sec shear rate. During the 5 weeks of rewarming the elevation of SBP and increased whole blood viscosity persisted, whereas the increased daily water consumption and expanded plasma volume returned to normal. Therefore, the acclimation to cold is accompanied by the development of a volume-associated hypertension, which is sustained after rewarming without volume expansion.

Acclimatization↗

PubMed1991

Psychrotrophy and foodborne Salmonella.

Recent reports on the behaviour of Salmonella at chill temperatures (less than 10 degrees C) raise concerns on the purported safety of refrigerated foods. The propensity for growth of salmonellae within 10-28 days in complex broth (5.9 degrees C) and agar (4.0 degrees C) media is overshadowed by more recent evidence on their capability to proliferate in fresh meats (2.0 degrees C) and shell eggs (4.0 degrees C) within 6 and 10 days, respectively. Such findings, together with the inability of many domestic refrigerators to maintain uniformly cold temperatures, are disquieting. Gaseous mixtures of CO2, N2 and O2 are widely used to extend the shelf life of chilled foods, notably fresh meats. The high levels of CO2 used in modified atmosphere packaging or generated by endogenous microflora in vacuum-packaged foods effectively inhibit the growth of psychrotrophic spoilage bacteria. Current evidence suggests that this industrial practice also arrests the growth of Salmonella but exerts little or no effect on their survival. Enhancement of the bacteriostatic potentials of pH and NaCl as temperature deviates from the optimum for growth to lower values could further contribute to the safety of chilled foods.

Cold Temperature↗

PubMed1976

The requirement for esterase activation in the anti-immunoglobulin-triggered movement of B lymphocytes.

In this paper we bring evidence suggesting that there is activation of an esterase upon reaction of anti-immunoglobulin antibodies (anti-Ig) with murine B lymphocytes. B lymphocytes upon exposure to anti-Ig cap the ligand-receptor complexes and immediately afterward become briefly motile. It is this latter step which is inhibitable by exposure to di-isopropyl phosphofluoridate (DFP). Various experimental manipulations indicated that treatment with anti-Ig activates the cell for motility which, however, is not manifested until the temperature is raised to 37 degrees C. The cell incubated with anti-Ig at cold temperatures becomes susceptible to the effect of DFP, suggesting that the antibody-treated cells are activated up to but not beyond the DFP inhibitable step. Exposure of cells to DFP and removal of it before their treatment with anti-Ig does not affect the anti-Ig-induced response. Four lines of evidence indicate that the reduction of lymphocyte movement of DFP is due to the inhibition of an esterase activated by the combination of antibody and cell: 1) The inhibition by DFP is irreversible; once DFP has reacted it can be washed away and the antibody-treated cell is still inhibited. 2) The inhibition increases with time of contact of lymphocytes and DFP and with the concentration of DFP. 3) A very poorly phosphorylating phosphonate, phenyl ethyl pentylphosphonate is completely inactive under conditions where an excellent phosphorylating phosphonate, p nitrophenyl ethyl pentylphosphonate maximally inactivated the cells' movement. 4) The amino acid esters, tosyl L arginine methyl ester and benzoyl arginine methyl ester specifically prevent the inactivation by DFP. The last finding suggests that tosyl L arginine methyl ester and benzoyl L arginine methyl ester might be substrates for the putative antibody-induced lymphocyte esterase. Lymphocytes incubated with antibody in the cold for more than 30 min lose their ability to move when the temperature is raised, suggesting that there is a time-dependent deactivation of the cell.

Amino Acids↗

PubMed1976

Cold agglutinin disease.

Development of the Coombs test has led to rapid progress in the recognition of various autoimmune hemolytic anemias. Cold agglutinin disease, a relatively rare disorder, occurs in idiopathic and secondary forms, the latter often in association with diseases that alter the immune status. The higher the titer of cold agglutinin, the greater is the thermal range of its activity. One of the characteristic clinical manifestations of the disease is striking cyanosis in acral areas on exposure to cold, which abates quickly on warming. This parallels the accelerated hemolysis at cold temperatures, which is reversible as heat is applied. In some patients, however, the disease is covert and is discovered only incidentally. The report of such a case is included.

Aged↗

PubMed2006

The PHD finger protein VRN5 functions in the epigenetic silencing of Arabidopsis FLC.

Vernalization, the acceleration of flowering by the prolonged cold of winter, ensures that plants flower in favorable spring conditions. During vernalization in Arabidopsis, cold temperatures repress FLOWERING LOCUS C (FLC) expression in a mechanism involving VERNALIZATION INSENSITIVE 3 (VIN3), and this repression is epigenetically maintained by a Polycomb-like chromatin regulation involving VERNALIZATION 2 (VRN2), a Su(z)12 homolog, VERNALIZATION 1 (VRN1), and LIKE-HETEROCHROMATIN PROTEIN 1. In order to further elaborate how cold repression triggers epigenetic silencing, we have targeted mutations that result in FLC misexpression both at the end of the prolonged cold and after subsequent development. This identified VERNALIZATION 5 (VRN5), a PHD finger protein and homolog of VIN3. Our results suggest that during the prolonged cold, VRN5 and VIN3 form a heterodimer necessary for establishing the vernalization-induced chromatin modifications, histone deacetylation, and H3 lysine 27 trimethylation required for the epigenetic silencing of FLC. Double mutant and FLC misexpression analyses reveal additional VRN5 functions, both FLC-dependent and -independent, and indicate a spatial complexity to FLC epigenetic silencing with VRN5 acting as a common component in multiple pathways.

Arabidopsis↗