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PubMed1996

[Urticaria caused by cold. 104 cases].

INTRODUCTION: Superficial and deep cold urticaria is a heterogeneous group of manifestations induced by exposure to cold (0 to 4 degrees C). Frequency is generally estimated at 2 to 3 p. 100. We studied retrospectively 104 patients meeting clinical, biological and therapeutic criteria of cold urticaria. PATIENTS AND METHODS: From 1981 to 1995, 1802 patients with urticaria were included in a standardized allergy survey. Among these patients, 104 met the criteria for the diagnosis of cold urticaria: positive test with 3 ice cubes placed on the skin for 5, 10 and 15 minutes or positive immersion test (immersion in 4 degrees C water for 15 minutes). Two groups of patients were excluded, those with systemic cold urticaria and those with minimal thermo-differential urticaria. RESULTS: Cold urticaria was found in 5.7 p. 100 of our urticaria patients, predominantly in young women. The triggering effect of cold was found at history taking in 71 p. 100 of the cases. The urticaria was usually superficial, more rarely associated with deep and/or mucosal urticaria. General signs were uncommon. The three ice cube test demonstrated significative biological and immunological abnormalities. In 5 cases, discrete cryoprecipitate was found (4 cryoglobulins, 1 cryofibrinogen). Although the search for an infectious agent was not conducted in absolutely all cases, there was no apparently remarkable association with infection the exception of VIH infection. Anti-H1 agents were given in 88.3 p. 100 of the cases leading to short-term improvement. Follow-up is insufficient to evaluate long-term outcome. DISCUSSION: This retrospective survey of 104 cases of cold urticaria was compared with data in the literature, particularly with the small number of studies including a large number of patients. We conclude that the diagnosis of cold urticaria can be based on history taking alone and the three ice cube tests (prognosis value, indication of reaction threshold). An exhaustive search for the cause is not indicated. A search for cryopathy should however always be done and followed by a complete work-up in case of positivity. Clinical signs other than cold urticaria suggesting a pathological response to cold require complete investigations.

Adolescent↗
PubMed1994

Sympathetic nervous activity to brown adipose tissue increases in cold-tolerant mice.

Brown adipose tissue (BAT) is thought to be responsible for increased heat production in cold-acclimated rodents. We measured sympathetic nerve activity (SNA) in interscapular BAT (IBAT) during cold stimulation in cold-acclimated C57BL/6J mice (ACCLI). Cold acclimation was achieved (cold tolerance was increased) by repeated exposure to cold stress every other week for 3 weeks. We compared SNA in these animals with SNA in mice that had no previous cold stress experience (naive). During the test, mice were anesthetized by urethane and isoflurane and were paralyzed with vecuronium bromide. Sympathetic nerve activity was recorded directly from one of the fine nerves to IBAT. The animal's body caudal to the pelvic area was covered with a plastic bag containing a slurry of ice water to decrease colonic temperature 7 degrees C below control level, which took approximately 20 min. Interscapular BAT-SNA increased during cold stress in both groups, but ACCLI mice had higher IBAT-SNA during cold stress than naive mice. These findings confirmed the hypothesis that during the acute cold exposure, cold-acclimated mice have greater sympathetic outflow to BAT adipocytes.

Acclimatization↗
PubMed1988

Analgesia induced by continuous versus intermittent cold water swim in the rat: differential effects of intrathecal administration of phentolamine and methysergide.

Continuous cold water swim produces analgesia that is partially mediated by a noradrenergic mechanism, but is independent of both serotonergic and opioid systems. On the other hand, intermittent cold water swim elicits analgesia which is partly mediated by an opioid mechanism; the contribution of the monoamines to the production of this analgesia is not known. Therefore, the present study was done to determine whether intermittent cold water swim is also mediated by noradrenergic and/or serotonergic substrates. Prior to either continuous (3.5 min) or intermittent (10 sec in, 10 sec out for 6 min) cold water (4 degrees C) swim, male Sprague-Dawley rats (225-250 g) were administered either the noradrenergic receptor blocker phentolamine (30 micrograms), the serotonergic blocker methysergide (30 micrograms) or artificial cerebrospinal fluid to the fifth lumbar vertebral spinal level via chronic intrathecal catheters. Phentolamine significantly attenuated the analgesia resulting from both continuous and intermittent cold water swim. Methysergide attenuated intermittent cold water swim analgesia, but was without effect on continuous cold water swim analgesia. Phentolamine, but not methysergide, also attenuated continuous footshock- (2.5 mA for 3 min) induced analgesia. The similarity between the effects of phentolamine and methysergide on continuous footshock and continuous cold water swim analgesia suggests that the effects of these drugs on cold water swim analgesia are not attributable to changes in thermoregulation. These results suggest that a spinal noradrenergic mechanism is involved in the mediation of both forms of cold water swim analgesia, whereas a spinal serotonergic mechanism is involved in only intermittent cold water swim analgesia.

Animals↗
PubMed1998

Continuous-flow cold therapy for outpatient anterior cruciate ligament reconstruction.

This prospective, randomized study evaluated continuous-flow cold therapy for postoperative pain in outpatient arthroscopic anterior cruciate ligament (ACL) reconstructions. In group 1, cold therapy was constant for 3 days then as needed in days 4 through 7. Group 2 had no cold therapy. Evaluations and diaries were kept at 1, 2, and 8 hours after surgery, and then daily. Pain was assessed using the VAS and Likert scales. There were 51 cold and 49 noncold patients included. Continuous passive movement (CPM) use averaged 54 hours for cold and 41 hours for noncold groups (P=.003). Prone hangs were done for 192 minutes in the cold group and 151 minutes in the noncold group. Motion at 1 week averaged 5/88 for the cold group and 5/79 the noncold group. The noncold group average visual analog scale (VAS) pain and Likert pain scores were always greater than the cold group. The noncold group average Vicodin use (Knoll, Mt. Olive, NJ) was always greater than the cold group use (P=.001). Continuous-flow cold therapy lowered VAS and Likert scores, reduced Vicodin use, increased prone hangs, CPM, and knee flexion. Continuous-flow cold therapy is safe and effective for outpatient ACL reconstruction reducing pain medication requirements.

Acetaminophen↗
PubMed1996

Do cold agglutinins have any impact on the outcome of liver transplantation?

Cold agglutinins, IgM red blood cell autoantibodies, cause cold agglutinin disease with hemolysis and microvascular occlusion. Cold preservation of kidneys during renal transplantation in the presence of cold agglutinins can cause graft malfunction. However, the impact of cold agglutinins on the outcome of liver transplantation is unknown. We measured the pretransplant presence and titer of cold agglutinins in 327 primary liver allograft recipients and analyzed their relationship to outcome after transplant. Thirty-three percent of pretransplant patients had cold agglutinins. Cold agglutinins were more common in patients with viral-related liver diseases (49%) compared with those with nonviral-related liver disease (32%). There was no difference between recipients with and without cold agglutinins in usage of blood products, postoperative day 2 aminotransferase levels, acute rejection at day 7, the development of hepatic artery thrombosis, nonanastomotic biliary strictures, or 4-month allograft survival. In conclusion, cold agglutinins are common in liver transplant patients before surgery, especially those with viral-related liver diseases. However, the presence of cold agglutinins does not impact on outcome after liver transplantation.

Agglutinins↗
PubMed1992

Induction of cold stability of microtubules in cultured tobacco cells.

In suspension-cultured tobacco (Nicotiana tabacum) cells, we have often encountered cold-stable microtubules (MTs). The cold-stable MTs were found in the pelleted fraction of tobacco cell homogenates. These cold-stable MTs were shown to be accompanied by unidentified filamentous structures that extended along part of their length. However, during the early hours in culture such cold-stable MTs were never observed. They were detectable from 120 h after the beginning of subculture and then their numbers increased gradually. The number of cells with cold-stable MTs eventually accounted for more than 95% of the total population of cells at the stationary phase of culture. The rapid loss of cold stability of MTs occurred when such cells were transferred to fresh medium for subculture. However, if the fresh medium was supplemented with once-used medium, the cold stability of MTs was retained. The active agent in the medium appeared to be of low molecular weight and to be heat resistant. A similar activity was detected in a pectin hydrolyzate. When an inhibitor of protein kinase, either 6-dimethylaminopurine or staurosporin, was added to the cells at an early stage of culture, when cold-stable MTs were normally completely absent, most cells acquired cold-stable MTs. It appears that acquisition or loss of cold stability of MTs in tobacco cells is regulated by the action of a kinase/phosphatase or a phosphorylation/dephosphorylation system on some MT protein(s), such as a cold stabilizer of MTs, some unidentified MT-associated filamentous structure, or even tubulin itself.

Journal Article↗
PubMed1987

Induction of freezing tolerance in spinach is associated with the synthesis of cold acclimation induced proteins.

Spinach (Spinacia oleracea L. cv Bloomsdale) seedlings cultured in vitro were used to study changes in protein synthesis during cold acclimation. Seedlings grown for 3 weeks postsowing on an inorganic-nutrient-agar medium were able to increase their freezing tolerance when grown at 5 degrees C. During cold acclimation at 5 degrees C and deacclimation at 25 degrees C, the kinetics of freezing tolerance induction and loss were similar to that of soil-grown plants. Freezing tolerance increased after 1 day of cold acclimation and reached a maximum within 7 days. Upon deacclimation at 25 degrees C, freezing tolerance declined within 1 day and was largely lost by the 7th day. Leaf proteins of intact plants grown at 5 and 25 degrees C were in vivo radiolabeled, without wounding or injury, to high specific activities with [(35)S]methionine. Leaf proteins were radiolabeled at 0, 1, 2, 3, 4, 7, and 14 days of cold acclimation and at 1, 3, and 7 days of deacclimation. Up to 500 labeled proteins were separated by two-dimensional gel electrophoresis and visualized by fluorography. A rapid and stable change in the protein synthesis pattern was observed when seedlings were transferred to the low temperature environment. Cold-acclimated leaves contained 22 polypeptides not found in nonacclimated leaves. Exposure to 5 degrees C induced the synthesis of three high molecular weight cold acclimation proteins (CAPs) (M(r) of about 160,000, 117,000, and 85,000) and greatly increased the synthesis of a fourth high molecular weight protein (M(r) 79,000). These proteins were synthesized during day 1 and throughout the 14 day exposure to 5 degrees C. During deacclimation, the synthesis of CAPs 160, 117, and 85 was greatly reduced by the first day of exposure to 25 degrees C. However, CAP 79 was synthesized throughout the 7 day deacclimation treatment. Thus, the induction at low temperature and termination at warm temperature of the synthesis of CAPs 160, 117, and 85 was highly correlated with the induction and loss of freezing tolerance. Cold acclimation did not result in a general posttranslational modification of leaf proteins. Most of the observed changes in the two-dimensional gel patterns could be attributed to the de novo synthesis of proteins induced by low temperature. In spinach leaf tissue, heat shock altered the pattern of protein synthesis and induced the synthesis of several heat shock proteins (HSPs). One polypeptide synthesized in cold-acclimated leaves had a molecular weight and net charge (M(r) 79,000, pI 4.8) similar to that of a HSP (M(r) 83,000, pI 4.8). However, heat shock did not increase the freezing tolerance, and cold acclimation did not increase heat tolerance over that of nonacclimated plants, but heat-shocked leaf tissue was more tolerant to high temperatures than nonacclimated or cold-acclimated leaf tissue. When protein extracts from heat-shocked and cold-acclimated leaves were mixed and separated in the same two-dimensional gel, the CAP and HSP were shown to be two separate polypeptides with slightly different isoelectric points and molecular weights.

Journal Article↗
PubMed2006

[Cold storage of rabbit platelet suspension by adding uridine diphosphate galactose].

This study was aimed to investigate the method to cold-store platelets with uridine diphosphate galactose (UDP-Gal). Rabbit heart blood was prepared for concentrated platelet suspension to which UDP-Gal was added, and then stored for ten days in 4 degrees C refrigerator. Thereafter, platelet count, mean platelet volume (MPV), platelet distributing width (PDW), platelet aggregation function, platelet activity to urge coagulation including PF3aT and APCT and apoptosis were determined. Meanwhile, survival time in vivo was tested after cold-stored rabbit platelets labeled with Cr51 were transfused into rabbits. The results showed that there was not significant difference for Plt count, MPV, PDW, PF3aT and APCT between UDP-Gal cold-stored platelet group and fresh platelet group (P > 0.05). On the contrary, platelet count decreased significantly, MPV, PDW jumped and PF3aT and APCT went down in cold control group as compared with fresh platelet group (P < 0.01). Apoptosis increased in UDP-Gal cold-stored platelet group as compared with fresh platelet group (P < 0.05), but was significantly lower than that in cold control group (P < 0.01). Although PagT (inducing reagent: C-PG) decreased, it could still be above 50% of fresh platelet. Survival time in rabbit in vivo was close between UDP-Gal cold-stored platelet group and fresh platelet group (P < 0.05). Survival rate in seventy-two hours after transfusion in the fresh platelet group, UDP-Gal cold-stored platelet group and cold control group was 57.5% +/- 7.2%, 50.3% +/- 6.3% and 0.1% +/- 0.5% respectively. It is concluded that the UDP-Gal can well protect cold-stored rabbit platelets and prolong the survival time of cold-stored platelets in vivo.

Animals↗
PubMed2005

Acute cooling of the feet and the onset of common cold symptoms.

BACKGROUND: There is a common folklore that chilling of the body surface causes the development of common cold symptoms, but previous clinical research has failed to demonstrate any effect of cold exposure on susceptibility to infection with common cold viruses. OBJECTIVE: This study will test the hypothesis that acute cooling of the feet causes the onset of common cold symptoms. METHODS: 180 healthy subjects were randomized to receive either a foot chill or control procedure. All subjects were asked to score common cold symptoms, before and immediately after the procedures, and twice a day for 4/5 days. RESULTS: 13/90 subjects who were chilled reported they were suffering from a cold in the 4/5 days after the procedure compared to 5/90 control subjects (P=0.047). There was no evidence that chilling caused any acute change in symptom scores (P=0.62). Mean total symptom score for days 1-4 following chilling was 5.16 (+/-5.63 s.d. n=87) compared to a score of 2.89 (+/-3.39 s.d. n=88) in the control group (P=0.013). The subjects who reported that they developed a cold (n=18) reported that they suffered from significantly more colds each year (P=0.007) compared to those subjects who did not develop a cold (n=162). CONCLUSION: Acute chilling of the feet causes the onset of common cold symptoms in around 10% of subjects who are chilled. Further studies are needed to determine the relationship of symptom generation to any respiratory infection.

Adolescent↗
PubMed2002

Influence of attendance at day care on the common cold from birth through 13 years of age.

OBJECTIVE: To describe trends in the occurrence of the common cold during the first 13 years of life among children who attended different childcare settings early in life. DESIGN: The Tucson Children's Respiratory Study involves 1246 children enrolled at birth and followed up prospectively since May 1980 through October 1984. Children with data regarding day care use during the first 3 years of life were included in this investigation (n = 991). Parents reported the occurrence of frequent (> or = 4) colds during the past year by questionnaire when each child was 2, 3, 6, 8, 11, and 13 years of age. Child care at home (no unrelated children), at small day care (1-5 unrelated children), or at large day care (> or = 6 unrelated children) was reported retrospectively by parental questionnaire when the children were approximately 6 years old. RESULTS: After adjusting for potential confounding variables, compared with children at home those in large day care had more frequent colds at year 2 (odds ratio [OR], 1.9, 95% confidence interval [CI], 1.0-3.4; P =.04), less frequent colds at years 6 (OR, 0.3, 95% CI, 0.1-0.9; P =.02) through 11 (OR, 0.4, 95% CI, 0.1-1.2; P =.09), and the same odds of frequent colds at year 13 (OR,1.0, 95% CI, 0.3-3.8; P =.95). In addition, compared with children in large day care for 1 year or less those attending large day care for more than 2 years had more frequent colds at year 2 (OR, 1.7, 95% CI, 1.0-3.0; P =.04), less frequent colds at years 6 (OR, 0.5, 95% CI, 0.2-1.1; P =.08), 8 (OR, 0.2, 95% CI, 0.1-1.0; P =.04), and 11 (OR, 0.3, 95% CI, 0.1-1.0; P =.05); and the same odds of frequent colds at year 13 (OR, 0.9, 95% CI, 0.3-2.9; P =.80). CONCLUSIONS: Attendance at large day care was associated with more common colds during the preschool years. However, it was found to protect against the common cold during the early school years, presumably through acquired immunity. This protection waned by 13 years of age.

Adolescent↗
PubMed2000

Vitamin C for preventing and treating the common cold.

BACKGROUND: The role of oral ascorbic acid (vitamin C) in the prevention and treatment of colds remains controversial despite many controlled trials. There have also been a number of efforts to synthesize and/or overview the results of these trials, and controversy over what these overviews tell us. OBJECTIVES: The objective of this review was to answer the following two questions: (1) Does regular high dosage supplementation with vitamin C reduce the incidence of colds? (2) Does taking vitamin C in high doses at the onset of a cold have a therapeutic effect? SEARCH STRATEGY: This review currently deals only with published trials from two previously published reviews by Kleijnen 1989 and Hemila 1992. SELECTION CRITERIA: Randomised and non-randomised trials of vitamin C taken to prevent or treat the common cold. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: Thirty trials were included. The quality of the included trials was variable. Vitamin C in doses as high as one gram daily for several winter months, had no consistent beneficial effect on incidence of the common cold. For both preventive and therapeutic trials, there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms. This effect was variable, ranging from -0.07% to a 39% reduction in symptom days. The weighted difference across all of the studies revealed a reduction of a little less than half a symptom day per cold episode, representing an 8% to 9% reduction in symptom days. There was no clear indication of the relative benefits of different regimes or vitamin C doses. However in trials that tested vitamin C after cold symptoms occurred, there was some evidence that a large dose produced greater benefits than lower doses. REVIEWER'S CONCLUSIONS: Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds. There appears to be a modest benefit in reducing duration of cold symptoms from ingestion of relatively high doses of vitamin C. The relation of dose to therapeutic benefit needs further exploration.

Administration, Oral↗
PubMed2002

Cold acclimation induces proliferation of sarcoplasmic reticulum without increase in Ca2+-ATPase activity in white axial muscle of striped bass (Morone saxatilis).

The effects of acclimation of striped bass to cold (5 degrees C) and warm (25 degrees C) temperatures upon ultrastructural features of white axial skeletal muscle are quantified. Surface density of sarcoplasmic reticulum (SR) increased by almost 30%, and SR volume density increased by about 20% during cold acclimation. Proliferation of SR suggests an increase in available SR surface for re-sequestration of Ca2+ and a decrease in diffusion path length for Ca2+ during cold acclimation. Average cross-sectional areas and cross-sectional perimeters of myofibrils situated in the center of muscle fibers decreased during cold acclimation by approximately 20% and 11%, respectively. Additionally, average major and minor axes of ellipses fit to central myofibrillar cross-sections decreased by approximately 12% and 8%, respectively, during cold acclimation. These measurements define a decrease in average myofibrillar diameter and suggest a decrease in diffusion path length for Ca2+ to and from myofibrillar activation sites. Measurements of peripheral myofibrils that had elongated profiles in cross-sections indicate that maximum profile length of these myofibrils decreases by about 17%. Peripheral myofibrils may break up into smaller myofibrils with more rounded cross-sectional profiles during cold acclimation. SR Ca2+-ATPase of white axial muscle was also measured in unfractionated homogenates and in crude SR-enriched subcellular fractions from cold- and warm-acclimated striped bass. No difference in SR Ca2+-ATPase activity per g wet weight was observed between cold- and warm-acclimated animals. Lack of increase in SR Ca2+-ATPase per g wet weight, despite a significant proliferation of SR, probably results in a decrease in average Ca2+-ATPase pump density within the SR membrane during cold acclimation. Thus, compensation for decreased diffusion coefficient of Ca2+ during cold acclimation appears due to the combined effects of proliferation of SR surface density and a decrease in average myofibrillar diameter.

Acclimatization↗
PubMed1996

Cold-induced salt intake in mice and catecholamine, renin and thermogenesis mechanisms.

Cold induces increased intake of salt in mice. To examine involvement of renin and catecholamines, male ICR mice were exposed to cold (7-9 degrees C; 6 h/day; 4 days), and half of them were allowed to choose between water and 0.9% NaCl. Plasma renin activity (PRA) and catecholamine concentrations in plasma, adrenal gland, kidney, brown adipose tissue (BAT) and brain were examined in three phases: for 9 h before exposure to cold, during 6 h of cold exposure and for 9 h after the exposure. The amount of salt intake from NaCl solution and from food, PRA and noradrenaline (NE) concentrations in kidney and medulla oblongata were higher during cold and the 9 h after exposure to cold than during the 9 h before the exposure. These results are consistent with the suggestion that cold induced catecholamine metabolism enhanced activity in the renin-angiotensin system, which played an important role in the arousal of salt appetite. During cold exposure, concentrations of NE and dopamine in BAT were higher in mice with access to NaCl solution than those without NaCl to drink. These results suggest that cold-induced salt intake enhanced non-shivering thermogenesis, and are consistent with our previous report that high salt intake helped to maintain colonic temperature under cold exposure.

Adipose Tissue, Brown↗
PubMed2000

Bile analysis as a tool for assessing integrity of biliary epithelial cells after cold ischemia--reperfusion of rat livers.

Previous morphological studies failed to show appreciable injury of biliary epithelial cells (BEC) after cold ischemia of rat liver, although recent evidence indicated that BEC integrity and function were impaired in this model. We tested the hypothesis that analysis of bile for enzymes, such as lactate dehydrogenase (LDH), alanine transaminase (ALT), and aspartate transaminase (AST), can be used for assessing cold ischemic injury of BEC. Furthermore, we examined whether biliary gamma-glutamyltransferase (GGT) reflects warm ischemic injury of BEC and whether normothermic reperfusion aggravates the negative effect of cold ischemia on BEC integrity and function. Rat livers were reperfused after different periods of cold or warm ischemia using a blood-free perfusion model. Compared with controls, perfusate LDH, ALT, and AST levels and parameters of hepatocyte function, including hepatocyte tight junction permeability, were not significantly altered by 18-h cold ischemia. On the other hand, 9-h cold ischemia markedly increased biliary LDH, ALT, and AST levels. However, only LDH release into the bile was strongly dependent on the time of cold storage. Biliary GGT, LDH, and glucose levels decreased during the reperfusion period following 18-h cold ischemia. The results suggest that biliary LDH can be used for assessing injury of BEC in cold-preserved livers and that normothermic reperfusion does not aggravate preservation-induced injury of BEC after cold ischemic storage.

Alanine Transaminase↗
PubMed2005

Effects of cold stimulation on secondary hyperalgesia (HA) induced by capsaicin in healthy volunteers.

Little is known about the sensory characteristics and underlying mechanisms behind secondary hyperalgesia (HA) (2 degrees HA). The aim of the present study was to investigate the relationships between two different noxious stimuli, mechanical and cold on capsaicin-induced 2 degrees HA. Fourteen healthy volunteers were exposed to three different cold stimuli (20, 10, 0 degrees C) 30 s each, on both forearms. The cold stimuli were applied before (baseline) and 8 min after intradermal administration of 50-microg capsaicin to the forearm, distally to the injection site in the inspected area of 2 degrees HA. Pain intensities were assessed immediately after each cold stimulus by means of a visual analogue scale (cold-VAS). Additionally, areas of mechanical HA (cm(2)) were assessed distally and proximally to the injection site at three different time points: 5, 8 (right after the second series of cold stimuli), and 30 min after the injection. No significant differences in cold-VAS were found between pre- and post-capsaicin injection at the tested forearm (P= 0.334), whereas significant reduction from pre- to post-injection was found in cold-VAS in the control forearm (P= 0.024). Further, 8 min after the injection, the cold stimulation led to an expansion of 2 degrees HA area (from 5.1+/-1.38 to 11.4+/-1.72 cm(2)) to punctuate stimuli distally but not proximally to the injection site (P<0.05). It is concluded that there is no HA to cold stimuli within the area of mechanical 2 degrees HA. However, cooling acts as a conditioning stimulus and expands the area of capsaicin-induced punctuate HA.

Adult↗
PubMed2006

Monitoring expression profiles of Arabidopsis genes during cold acclimation and deacclimation using DNA microarrays.

A comparative analysis of gene expression profiles during cold acclimation and deacclimation is necessary to elucidate the molecular mechanisms of cold stress responses in higher plants. We analyzed gene expression profiles in the process of cold acclimation and deacclimation (recovery from cold stress) using two microarray systems, the 7K RAFL cDNA microarray and the Agilent 22K oligonucleotide array. By both microarray analyses, we identified 292 genes up-regulated and 320 genes down-regulated during deacclimation, and 445 cold up-regulated genes and 341 cold down-regulated genes during cold acclimation. Many genes up-regulated during deacclimation were found to be down-regulated during cold acclimation, and vice versa. The genes up-regulated during deacclimation were classified into (1) regulatory proteins involved in further regulation of signal transduction and gene expression and (2) functional proteins involved in the recovery process from cold-stress-induced damages and plant growth. We also applied expression profiling studies to identify the key genes involved in the biosynthesis of carbohydrates and amino acids that are known to play important roles in cold acclimation. We compared genes that are regulated during deacclimation with those regulated during rehydration after dehydration to discuss the similarity and difference of each recovery process.

Acclimatization↗
PubMed1989

Analysis of avian cold receptor function.

The response characteristics of facial specific cold receptors of the pigeon were studied quantitatively by recording single unit activity from the trigeminal ganglion at various stimulus conditions and subsequent analysis of the discharge pattern. Responses to maintained temperatures as well as to cooling steps were qualitatively identical to those seen in the corresponding mammalian cold receptor populations, but avian cold receptors were generally less sensitive, particularly to dynamic stimuli. The major differences between avian and mammalian cold receptors were that avian cold units only occasionally discharged in periodic groups of impulses at constant temperatures and that there was no indication of cyclic receptor events being involved in the dynamic response to cooling, as it is the case in all mammalian cold sensors. Additionally, the temporal pattern of the grouped discharges was less regular in avian cold units. Application of calcium, EGTA and menthol revealed a comparatively low dependence of cold receptor function on external calcium. The results provide evidence that calcium-controlled processes and periodic receptor events contribute only insignificantly to the signal transduction of avian cold receptors. This indicates a different functional organization of the transducer processes of avian and mammalian cold receptors.

Action Potentials↗
PubMed1991

Effect of the exposure to chronic-intermittent cold on the thyrotropin and thyroid hormones in the rat.

Rats exposed to acute cold (4 degrees C for 2 h), chronic cold (4 degrees C), and chronic-intermittent cold (4 degrees C for 2 h daily) were killed after 1, 2, 3, 4, and 10 days of cold exposure. The control group was maintained at 25 degrees C. In each animal, the plasma concentration of thyrotropine (THS), triiodothyronine (T3), and thyroxine (T4) was determined by radioimmunoassay. At the initial time of exposure, elevations in TSH, T3, and T4 were observed in the rats in each experimental group. However, on the 10th day, in rats exposed to chronic-intermittent cold, TSH, T3, and T4 decreased to values lower than the control values. In animals exposed to acute cold as well as to chronic cold no differences were found, with respect to the controls, in TSH and T4. In rats exposed to acute cold for 10 days, the T3 value was lower than the control value; however, in animals exposed to chronic cold, T3 was same as that in the controls. The results indicate that, in the rat, exposure to chronic-intermittent cold produces an inhibition in the secretion of TSH and thyroid hormones.

Animals↗