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PubMed2004

Impact of cold and cold-acid stress on poststress tolerance and virulence factor expression of Escherichia coli O157:H7.

The effect of extended cold or cold-acid storage of Escherichia coli O157:H7 on subsequent acid tolerance, freeze-thaw survival, heat tolerance, and virulence factor (Shiga toxin, intimin, and hemolysin) expression was determined. Three E. coli O157:H7 strains were stressed at 4 degrees C in TSB or pH 5.5 TSB for 4 weeks. The acid (TSB [pH 2.0] or simulated gastric fluid [pH 1.5]) tolerance, freeze-thaw (-20 degrees C to 21 degrees C) survival, and heat (56 degrees C) tolerance of stressed cells were compared with those of control cells. The beta-galactosidase activities of stressed and control cells containing a lacZ gene fusion in the stx2, eaeA, or hlyA gene were determined following stress in TSB or pH 5.5 TSB at 37 degrees C and in the exponential and stationary phases. Cold and cold-acid stresses decreased acid tolerance (P < 0.05), with a larger decrease in acid tolerance being observed after cold stress than after cold-acid stress (P < 0.05). Cold stress increased freeze-thaw survival for all three strains (P < 0.05). Prior cold or cold-acid stress had no effect on virulence factor production (P > 0.05), although growth in acidic media (pH 5.5) enhanced eaeA and hlyA expression (P < 0.05). These results indicate that the prolonged storage of E. coli O157:H7 at 4 degrees C has substantial effects on freeze-thaw tolerance but does not affect subsequent virulence gene expression.

Adaptation, Physiological↗
PubMed1994

Altered pain and temperature perception following cingulotomy and capsulotomy in a patient with schizoaffective disorder.

Recent studies have renewed interest in the role of limbic structures, such as the cingulate cortex, in nociception. To investigate the involvement of the limbic system in pain and temperature perception further, we have quantified ratings of innocuous and noxious thermal stimuli in a patient with schizoaffective disorder before and after 2 surgical procedures. Psychophysical tests were conducted at a control session prior to surgery. Postoperative test sessions were conducted up to 10 weeks after bilateral cingulotomy and for 3 months after a subsequent bilateral anterior internal capsulotomy. A contact thermal stimulator delivered ascending (39-50 degrees C) and descending (22-2 degrees C) series of stimuli to the patient's volar forearm. The patient was trained to rate the innocuous warmth and cold and the pain associated with each stimulus. A cold pressor test was used to obtain a measure of cold pain tolerance. Compared to pre-operative levels, cingulotomy/capsulotomy resulted in moderately diminished warmth perception and an elevated heat pain threshold and increased ratings to suprathreshold noxious heat stimuli (hyperpathia). Prior to surgery, the patient perceived all cold stimuli as cold but not painful. However, after cingulotomy and capsulotomy, cold stimuli were rated significantly colder and stimuli less than or equal to 12 degrees C evoked pain. Compared to normal control subjects, the patient's ratings of innocuous and noxious cold stimuli were reduced pre-operatively but elevated postoperatively and cold pain tolerance was elevated pre-operatively but reduced postoperatively. These altered ratings of noxious heat and cold stimuli were reflected on both a pain intensity and pain affect (unpleasantness) scale. In summary, these data suggest that cingulotomy and capsulotomy disinhibited the patient's noxious heat and cold appreciation. These findings provide support for a role of the cingulate cortex and frontal cortical regions in the perception of innocuous and noxious thermal stimuli and suggest that under normal conditions, these areas may act to suppress the subjective intensity of noxious heat and cold.

Adult↗
PubMed2003

Neurophysiologic evidence for a central sensitization in patients with fibromyalgia.

OBJECTIVE: To determine whether abnormalities of peripheral and central nociceptive sensory input processing exist outside areas of spontaneous pain in patients with fibromyalgia (FM) as compared with controls, by using quantitative sensory testing (QST) and a neurophysiologic paradigm independent from subjective reports. METHODS: A total of 164 outpatients with FM who were attending a self-management program were invited to participate in the study. Data for 85 patients were available and were compared with those for 40 non-FM controls matched for age and sex. QST was performed using thermal, mechanical, and electrical stimuli at locations of nonspontaneous pain. Pain assessment was 2-fold and included use of subjective scales and the spinal nociceptive flexion reflex (NFR), a specific physiologic correlate for the objective evaluation of central nociceptive pathways. Questionnaires regarding quality of life and the impact of FM were available. RESULTS: Participants were mainly middle-aged women, with a mean disease duration of 8 years. Between-group differences were significant for neurophysiologic, clinical, and quality of life measures. In patients with FM, peripheral QST showed significantly altered cold and heat pain thresholds, and tolerance to cold pain was radically reduced. The median NFR threshold in patients with FM (22.7 mA [range 17.5-31.7]) was significantly decreased compared with that in controls (33 mA [range 28.1-41]). A cutoff value of <27.6 mA for NFR provided sensitivity of 73% and specificity of 80% for detecting central allodynia in the setting of FM. CONCLUSION: Our results strongly, although indirectly, point to a state of central hyperexcitability of the nociceptive system in patients with FM. The NFR can be used to assess central allodynia in FM. It may also help discriminate patients who may benefit from use of centrally acting analgesics.

Female↗
PubMed1986

The role of self-efficacy expectancies in the prediction of pain tolerance.

The association of self-efficacy expectancies with pain tolerance on the cold pressor test was examined during treatment conditions of setting quotas alone and in conjunction with monetary reinforcement and placebos in 64 college volunteers. It was found that quota setting was an effective means of increasing cold pressor pain tolerance. The addition of monetary reinforcement of quota achievement did not enhance performance, while the addition of a placebo decreased the effectiveness of quota setting. Self-efficacy expectancies were significantly correlated with pain tolerance times and were better predictors of tolerance than pain ratings. Self-efficacy expectancies and pain tolerance times at treatment were both found to predict 1 week follow-up performance.

Humans↗
PubMed2000

Avoidance versus focused attention and the perception of pain: differential effects for men and women.

The aim of the current investigation was to compare the effects of two different attentional strategies (focused vs. avoidance) on how males and females respond to experimentally induced pain. One hundred healthy adults were instructed to either attend towards or away from cold pressor pain. Measures of pain tolerance, pain threshold and recovery were taken, as were self-report measures of sensory and affective pain experiences. As expected, gender was found to moderate tolerance to pain: males were found to be more tolerant to cold pressor pain than females. With respect to the self-report measures, males reported less sensory pain when they attended toward the pain than when they avoided it. However, a similar effect was not found in women, suggesting that attentional focusing may only be a useful strategy for males. These results are discussed in light of previous research.

Adaptation, Psychological↗
PubMed2004

A single amino acid substitution in the Arabidopsis FIERY1/HOS2 protein confers cold signaling specificity and lithium tolerance.

Low temperature induces the expression of many plant genes through undefined signaling pathways. To gain insight into cold signal transduction mechanisms, we isolated Arabidopsis mutants that exhibited altered regulation of low temperature-induced gene expression. One such mutant, hos2, was shown previously to have an enhanced induction of stress-responsive genes by cold, whereas the expression of these genes under osmotic stress or the phytohormone absciscic acid (ABA) treatments was not affected. Here we further define the targets of HOS2 by examining the regulation of upstream cold-specific CBF transcription factor genes. It was found that the transcript levels of CBF2 and CBF3 were significantly higher in hos2 mutant plants than in the wild type under cold treatments, suggesting that HOS2 may act upstream of CBFs. The HOS2 gene was cloned using a map-based strategy. Surprisingly, HOS2 is identical to the FIERY1 gene that we had described previously. FIERY1 is a general negative regulator that controls cold, osmotic stress, and ABA signal transduction and possesses inositol polyphosphate 1-phosphatase activity. The hos2 mutation rendered the HOS2/FIERY1 recombinant protein completely inactive in the cold but did not substantially affect its activity at warm temperatures. Interestingly, the hos2 mutant protein is extremely tolerant to Li+. This study provides a unique example of a single amino acid substitution in a critical regulator that can lead to conditional changes in protein functions and distinct plant phenotypes. The results reinforce the notion that phosphoinositols are important second messengers in cold signal transduction, and shed light on how the diversity of plant tolerance to cold and other abiotic stresses may evolve due to variations in a common molecular switch.

Amino Acid Sequence↗
PubMedDate not supplied

Thermal sensitivity of Drosophila melanogaster: evolutionary responses of adults and eggs to laboratory natural selection at different temperatures.

We compared aspects of the thermal sensitivity of replicated lines of Drosophila melanogaster that had been evolving by laboratory natural selection at three selection temperatures: 16.5 degrees C (10+ yr), 25 degrees C (9+ yr), or 29 degrees C (4+ yr). The 16.5 degrees C and 25 degrees C lines are known to have diverged in fitness at 16.5 degrees C versus 25 degrees C and also in heat tolerance. We designed new experiments to explore further possible shifts in thermal sensitivity of these lines. The optimal temperature for walking speed of adults was positively related to selection temperature, but differences among lines in thermal sensitivity of walking speed were small. Performance breath was inversely related to selection temperature. Tolerance of adults to an acute heat shock was also positively related to selection temperature, but tolerance to a cold shock was not. Thus, fitness at moderately high temperatures is genetically coupled with tolerance of extreme high (but not of low) temperature. Knock-down temperature and walking speed at high temperature, however, were independent of selection temperature. In contrast to adults, eggs from different lines had similar heat and cold tolerance. Thus, long-term natural selection has led to divergence in thermal sensitivity of some (but not of all) traits and may have had more of an impact on adults than on eggs. Attempts to predict evolutionary states in nature are, however, complicated because of the observed genetic correlations and the simple selection scheme.

Adaptation, Physiological↗
PubMed2006

gid1, a gibberellin-insensitive dwarf mutant, shows altered regulation of probenazole-inducible protein (PBZ1) in response to cold stress and pathogen attack.

A recessive gibberellin (GA)-insensitive dwarf mutant of rice, gibberellin-insensitive dwarf1 (gid1), has been identified, which shows a severe dwarf phenotype and contains high concentrations of endogenous GA. To elucidate the function of gid1, proteins regulated downstream of gid1 were analysed using a proteomic approach. Proteins extracted from suspension-cultured cells of gid1 and its wild type were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Of a total of 962 proteins identified from the suspension-cultured cells, 16 were increased and 14 were decreased in gid1 compared with its wild type. Among the proteins hyper-accumulated in gid1 were osmotin, triosephosphate isomerase, probenazole inducible protein (PBZ1) and pathogenesis-related protein 10. Of these four genes, only the expression of PBZ1 was increased by exogenous GA3 application. Expression of this gene was also enhanced in shoots of the wild type by cold stress or by rice blast fungus infection. Under normal growth conditions, there was more PBZ1 protein in gid1 than in the wild type. In addition, gid1 showed increased tolerance to cold stress and resistance to blast fungus infection. The entcopalyl diphosphate synthase (OsCPS) genes, which encode enzymes at the branch point between GA and phytoalexin biosynthesis, were expressed differentially in gid1 relative to the wild type. Specifically, OsCPS1, which encodes an enzyme in the GA biosynthesis pathway, was down-regulated and OsCPS2 and OsCPS4, which encode enzymes in phytoalexin biosynthesis, were up-regulated in gid1. These results suggest that the expression of PBZ1 is regulated by GA signalling and stress stimuli, and that gid1 is involved in tolerance to cold stress and resistance to blast fungus.

Abscisic Acid↗
PubMed2004

The myth of pulmonary Raynaud's phenomenon: the contribution of pulmonary arterial vasospasm in patients with systemic sclerosis related pulmonary arterial hypertension.

OBJECTIVE: To investigate the contribution of cold induced pulmonary vasospasm by peripheral and central cold stimulus in exacerbating pulmonary arterial hypertension (PAH) in patients with systemic sclerosis undergoing cardiac catheterisation. METHODS: In a prospective pilot study, 21 patients with systemic sclerosis and catheter proven PAH had mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac output (CO) measured before and after peripheral (hand immersion into cold water at 10-15 degrees C for two minutes if tolerated) and central (direct cold water at 4 degrees C injected into the right atrium) cold pressor challenge. Markers of endothelial activation, platelet function, and nitric oxide degradation were measured in blood sampled from the pulmonary artery. RESULTS: 19 of the patients (mean (SD) age, 56 (4) years; baseline mPAP, 34 (8) mm Hg; PVR, 420 (87) dyne.s.cm(-5); CO, 6.4 (1.8) l/min) tolerated cold hand immersion for the maximum two minute duration. All 21 tolerated central cold pressor challenge (three to five injections of 10 ml saline boluses at 4 degrees C). There was no significant change in haemodynamics after cold challenge by either route of provocation. Levels of endothelin-1, von Willebrand factor, fibrinogen, and 3-nitrotyrosine were raised compared with control values in patients with systemic sclerosis but without PAH, but did not change significantly after peripheral cold challenge. CONCLUSIONS: Pulmonary vasospasm in response to peripheral and centrally administered cold pressor challenge is unlikely to contribute to persistence of pulmonary arterial hypertension in patients with systemic sclerosis.

Adult↗
PubMed2006

Transcriptional regulatory networks in cellular responses and tolerance to dehydration and cold stresses.

Plant growth and productivity are greatly affected by environmental stresses such as drought, high salinity, and low temperature. Expression of a variety of genes is induced by these stresses in various plants. The products of these genes function not only in stress tolerance but also in stress response. In the signal transduction network from perception of stress signals to stress-responsive gene expression, various transcription factors and cis-acting elements in the stress-responsive promoters function for plant adaptation to environmental stresses. Recent progress has been made in analyzing the complex cascades of gene expression in drought and cold stress responses, especially in identifying specificity and cross talk in stress signaling. In this review article, we highlight transcriptional regulation of gene expression in response to drought and cold stresses, with particular emphasis on the role of transcription factors and cis-acting elements in stress-inducible promoters.

Adaptation, Physiological↗
PubMed1998

Metabolic engineering of rice leading to biosynthesis of glycinebetaine and tolerance to salt and cold.

Genetically engineered rice (Oryza sativa L.) with the ability to synthesize glycinebetaine was established by introducing the codA gene for choline oxidase from the soil bacterium Arthrobacter globiformis. Levels of glycinebetaine were as high as 1 and 5 micromol per gram fresh weight of leaves in two types of transgenic plant in which choline oxidase was targeted to the chloroplasts (ChlCOD plants) and to the cytosol (CytCOD plants), respectively. Although treatment with 0.15 M NaCl [corrected] inhibited the growth of both wild-type and transgenic plants, the transgenic plants began to grow again at the normal rate after a significantly less time than the wild-type plants after elimination of the salt stress. Inactivation of photosynthesis, used as a measure of cellular damage, indicated that ChlCOD plants were more tolerant than CytCOD plants to photoinhibition under salt stress and low-temperature stress. These results indicated that the subcellular compartmentalization of the biosynthesis of glycinebetaine was a critical element in the efficient enhancement of tolerance to stress in the engineered plants.

Acclimatization↗
PubMed2002

Energy and water conservation in frozen vs. supercooled larvae of the goldenrod gall fly, Eurosta solidaginis (fitch) (Diptera: Tephritidae).

Insects that tolerate severe cold during winter may either supercool or tolerate ice forming within the tissues of the body. To compare the relative advantages of freezing and supercooling, we measured rates of CO(2) production and water loss in frozen and supercooled goldenrod gall fly larvae (Eurosta solidaginis). As an important first step, we measured the time required for ice content and metabolic rate to stabilize upon freezing. Ice content stabilized after only three hours of freezing at -5 degrees C, whereas CO(2) production required 12 hours to stabilize. Subsequent experiments found that freezing greatly reduced both water loss and metabolic rate. Comparisons of supercooled and frozen larvae at -5 degrees C indicated that CO(2) production fell 47% with freezing and water loss decreased 35%. As temperature decreased to -10 and -15 degrees C, CO(2) production fell exponentially and was no longer detectable at -20 degrees C with our measurement system. Our results demonstrate that freezing significantly reduces energy consumption during the winter and may therefore improve winter survival and spring fecundity. The advantages of freezing over supercooling would drive selection toward insect freeze tolerance and also toward higher supercooling points to increase the duration of freezing each winter.

Adaptation, Physiological↗
PubMed2001

Experimental pain and psychologic status of patients with chest pain with normal coronary arteries or ischemic heart disease.

BACKGROUND: The cause of chest pain in patients with a normal coronary angiogram (NCA) remains an enigma. Also, it is unclear whether psychosocial factors play a role in the etiology of chest pain in these patients. The objective of the current study was to compare psychosocial factors, clinical pain, and responses to experimental pain in NCA patients, patients with ischemic heart disease (IHD), and healthy control subjects. METHODS: Pain intensity, threshold, and tolerance to cold pressor pain were assessed in 30 NCA patients, 30 IHD patients, and 30 healthy control subjects matched for age, sex, and sociodemographic factors. All subjects completed questionnaires measuring a number of psychosocial factors, including stress, anxiety, depression, extroversion, and neuroticism. NCA and IHD patients also completed questionnaires assessing clinical pain responses and pain-coping strategies. RESULTS: With the exception of a lower tolerance to cold pressor pain of IHD patients (P <.05), no significant differences were found between NCA and IHD patients with respect to other clinical pain measures, psychosocial measures, pain-coping strategies, and other pain-related behaviors. Healthy control subjects differed significantly (P <.05) from both IHD and NCA patients with respect to maximum cold pressor pain, depression, and state anxiety and from IHD patients with respect to intensity of cold pressor pain, threshold to cold pressor pain, and perceived stress. CONCLUSIONS: The results suggest that higher scores on various psychosocial measures in both chest pain groups are related to their pain, rather than being the cause of pain, and do not support a psychogenic explanation for chest pain in the presence of normal coronary arteries.

Adaptation, Psychological↗
PubMed1982

Commentary on the reduced urinary noradrenaline excretion following cold stress and exercise in physically trained rats.

Urinary catecholamine excretions of rats trained by swimming or running were compared with those of cold-acclimated rats and controls i.e. sedentary warm-acclimated rats. During cold stress the trained rats excreted less noradrenaline (NA) than did controls. In fact rats trained by swimming excreted less NA than did cold-acclimated rats, while rats trained by running excreted about the same amount as did cold-acclimated rats. 2 h of swimming increased the urinary catecholamine (CA) excretion of all groups but trained rats excreted less NA than did controls and cold-acclimated rats, which had excretions of similar magnitude. The NA excretions of the two trained groups never deviated statistically from each other. It is concluded that concerning NA requirement in order to maintain homeostasis, training produces "cross tolerance" to cold stress but cold-acclimation does not produce "cross tolerance" to acute exercise. Furthermore the positive effect of training on NA excretion during the stress of cold or that of acute exercise seems essentially to be an effect of increased locomotor activity as such regardless of the type of training. It is also suggested that increased levels of locomotor activity of the rat may be of importance for seasonal acclimation of the species by increasing its tolerance to cold.

Animals↗
PubMed1988

Abscisic Acid-regulated gene expression in relation to freezing tolerance in alfalfa.

A comparison of abscisic acid (ABA)-induced and cold-acclimation-induced freezing tolerance in two alfalfa cultivars (Medicago falcata cv Anik and Medicago sativa v Trek) indicates that ABA alone can increase freezing tolerance to some extent, but for the development of maximum tolerance, cold acclimation is essential. Analysis of in vivo-labeled proteins of ABA-treated seedlings reveals that ABA causes several changes in the pattern of protein synthesis. While some of these changes appear to be similar to those induced by cold acclimation, others seem to be specific to ABA treatment. From a cDNA library constructed against poly(A(+)) RNA of a freezing-tolerant alfalfa cultivar, Anik, a cDNA clone, pSM1409, has been isolated. Expression of the gene corresponding to this clone, as determined by northern hybridization, is regulated most likely at the transcriptional level by cold acclimation and exogenously supplied ABA. However, the increase in the transcript level is much greater in the freezing-tolerant cultivar Anik than in the relatively freezing-sensitive cultivar, Trek. The role of ABA in the acquisition of freezing tolerance is discussed.

Journal Article↗
PubMed1950

Dehydrogenated alkaloids of ergot in treatment of peripheral vascular diseases.

The dihydrogenated alkaloids of ergot, dihydroergocornine (DHO 180) and an equal mixture of dihydroergocornine, dihydroergocristine and dihydroergokryptine known as CCK 179 have been found to be therapeutic adjuncts in the medical treatment of peripheral vascular diseases. Their action is primarily that of adrenergic blockage, although depression of the brain stem is to be considered. The mixture of alkaloids (CCK 179) was found to be more effective than a single alkaloid, dihydroergocornine (DHO 180). A greater number of patients were benefited, relief of symptoms was greater and the dosage easier to establish. A favorable therapeutic response of clinical significance with the mixture was obtained in approximately 60 per cent of all cases investigated. It was of greater benefit in the organic occlusive diseases, where a larger percentage of favorable responses was obtained than in the purely vasospastic disorders. Orally and subcutaneously, CCK 179 exhibited vasodilating properties which compared favorably with paravertebral and peripheral nerve block, reflex heat, alcohol and sympathectomy. Surface temperatures were elevated, oscillometric readings increased and tolerance to cold increased in a statistically significant number of cases. Effects of sympathectomies were frequently enhanced. Following subcutaneous administration, increased surface temperatures of the extremities of one to two hours' duration were obtained in 90 per cent of all cases.Paresthesias, nocturnal cramps and intermittent claudication were improved. A sense of well-being was occasionally exhibited. Blood pressure and pulse rates were rarely affected. Blood pressure was lowered in normotensive patients, but was rarely changed in hypertensive patients. Symptoms of overdosage appeared after two to three months of continuous therapy. These were manifested by lowered surface temperatures, decreased tolerance to cold, return of intermittent claudication and occasionally by vague general discomfort. These symptoms disappeared on cessation of therapy. Improvement frequently followed. In only one case was there an immediate reaction. Following subcutaneous administration of CCK, blood pressure and pulse rate increased and oscillometric readings and surface temperatures decreased. Frequent courses of therapy with interruptions were necessary for maintenance of improvement.

Alkaloids↗