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At least 649 records · Page 36Linked to original sources
PubMed1995

"Cardioplegia on the contractile apparatus level": evaluation of a new concept for myocardial preservation in perfused pig hearts.

UNLABELLED: The concept of a reversible desensitization of the myocardial contractile apparatus for calcium by 2,3 Butanedione Monoxime (BDM) as a method to improve the myocardium's tolerance to cold ischemia was evaluated in normal pig hearts (n = 14). The results were compared to those obtained after application of Bretschneider's HTK cardioplegic solution. METHODS: Series I) After BDM treatment (concentrations: 0-30 mmol/L) the isometric force output and the intracellular calcium transients (measured using the FURA-2 ratio method) of electrically driven (1 Hz) isolated left-ventricular muscle strips excised from beating pig hearts (n = 14) were recorded simultaneously in order to analyse the mode of action of BDM; Series II) The cardioprotective effects of BDM (30 mmol/L) and Bretschneider's cardioplegic solution (HTK) were compared in a large-animal model: after "in situ perfusion" of pig hearts with either 2000 ml ice-cold BDM solution (30 mmol/L) (n = 7) or 2000 ml HTK (n = 7) the hearts were explanted and stored at 4 degrees C in the same solutions for up to 42 h. The contractile properties of muscle fibres, excised after storage periods of 8, 24, and 42 h from these hearts were analyzed in terms of isometric force development and isotonic shortening. 280 muscle fibres from 14 pigs were used for measurements. RESULTS: Series I) In pig myocardium a dose-dependent reduction of isometric force development was found after BDM application. The shape and the amplitude of the intracellular calcium transient were also affected by BDM. At 30 mmol/L BDM no force development could be elicited despite the presence of an intracellular calcium transient (amplitude < 70% of the control). Series II) Shortening, calcium transient, and force of left-ventricular muscle strips of pig myocardium excised after storage periods for up to 42 h showed complete recovery when BDM was applied. In contrast HTK perfusion allowed complete recovery of these parameters when the storage period did not exceed 6 hours. CONCLUSION: Under the given experimental conditions reversible desensitization of the contractile apparatus for calcium results in a considerable prolongation of the tolerance to cold ischemia in explanted pig hearts. The present study shows that the protective effects of BDM are not only present when isolate muscle fibres were stored (and the extracellular space is large) but also after storage of complete hearts in a solution in a solution containing BDM. Thus BDM may become a useful agent to enlarge the storage period of donor hearts in heart transplatation considerably.

Animals↗
PubMed2026

DeepLabCut-based automated system reveals diverse temperature tolerance among medaka strains and related Oryzias species.

Temperature is a critical environmental factor influencing the physiology and behavior of ectothermic animals, yet conventional methods for evaluating thermal tolerance in fish rely on subjective manual observation of loss of equilibrium (LOE), limiting experimental throughput and introducing observer bias. Here, we developed an automated temperature tolerance evaluation system integrating DeepLabCut-based pose estimation with custom image processing algorithms to objectively quantify the timing of LOE during thermal stress tests. Our system incorporated region partitioning and color transformation preprocessing to improve keypoint detection accuracy, followed by a classification model combining ResNet34-based frame features with keypoint coordinates to objectively determine the timing of LOE without manual observation. Validation against manual annotation showed that the automated system achieved an accuracy comparable to the natural variability between trained investigators, and outperformed naive human observers, supporting its validity as an objective and reproducible alternative to manual scoring. Using this system, we characterized cold and heat tolerance across six medaka strains (Oryzias latipes: d-rR/TOKYO, HB11A, OK-Cab, HO5 and HdrR-II1; O. sakaizumii: HNI-II). Cold and heat tolerance assessment revealed inter-strain variation, with HdrR-II1 among the most cold- and heat-tolerant strains and HNI-II the least tolerant of both cold and heat stress. We further evaluated cold tolerance in medaka-related species (O. sinensis, O. cabaranensis, O. curvinotus, O. luzonensis, O. celebensis, and O. javanicus) and zebrafish (Danio rerio), revealing substantial interspecific variation that broadly corresponded with latitudinal distribution. O. latipes, distributed at the highest latitudes among the tested species, exhibited the greatest cold tolerance, whereas O. celebensis, O. javanicus, and other tropical or low-latitude species showed comparatively low cold tolerance. Our automated system provides a robust, high-throughput platform for thermal tolerance evaluation and, combined with the genetic and genomic resources available in medaka, establishes a foundation for elucidating the molecular mechanisms underlying temperature adaptation in fish.

Animals↗
PubMed1991

Tolerance to topical preparations: cold or warm?

Ocular irritation from topical preparations is related to their viscosity, osmolarity, and pH value. We investigated the effect of temperature on ocular discomfort in 40 volunteers without a history of neuropathy and keratopathy. The dilating drops, tropicamide and phenylephrine were available at two different temperatures, 4 degrees C ("cold") versus 20 degrees C ("warm"). Each patient received cold drops in one eye and warm drops in the fellow eye. Ocular discomfort was similar in both groups. Eyes that received cold drops had a delayed irritation versus an instantaneous irritation with the warm drops. Cold drops may have a transient anesthetic effect on pain nerve endings that fades once the drops warm up to body temperature.

Administration, Topical↗
PubMed2004

Overexpression of the rice Osmyb4 gene increases chilling and freezing tolerance of Arabidopsis thaliana plants.

The expression of the gene Osmyb4, detected at low level in rice (Oryza sativa) coleoptiles grown for 3 days at 29 degrees C, is strongly induced by treatments at 4 degrees C. At sublethal temperatures of 10 and 15 degrees C, its expression in rice seedlings is already evident, but this effect cannot be vicariated by other stresses or ABA treatment. We demonstrate by transient expression that Myb4 transactivates the PAL2, ScD9 SAD and COR15a cold-inducible promoters. The Osmyb4 function in vivo is demonstrated overexpressing its cDNA in Arabidopsis thaliana plants (ecotype Wassilewskija) under the control of the constitutive CaMV 35S promoter. Myb4 overexpressing plants show a significant increased cold and freezing tolerance, measured as membrane or Photosystem II (PSII) stability and as whole plant tolerance. Finally, in Osmyb4 transgenic plants, the expression of genes participating in different cold-induced pathways is affected, suggesting that Myb4 represents a master switch in cold tolerance.

Acclimatization↗
PubMed2025

Analysis of genetic differences underlying chilling stress tolerance using whole genome Re-Sequencing in walnut (Juglans regia L.).

Walnut (Juglans regia L.) is prized worldwide for both its nutritional value and economic importance, yet it remains vulnerable to cold stress, with significant differences in tolerance among varieties. This study combined physiological analyses with whole-genome resequencing (WGS) to evaluate the cold stress responses of two varieties, &#x2018;Qingxiang&#x2019; and &#x2018;Liaoning No.8&#x2019;. Under chilling stress (0&#xa0;&#xb0;C), we measured electrolyte leakage and antioxidant enzyme activity, applying both exogenous methyl jasmonate (MeJA) and the jasmonate inhibitor DIECA. Genomic variations were analyzed using WGS. Results showed that &#x2018;Liaoning No.8&#x2019; exhibited superior cold tolerance. Application of MeJA reduced electrolyte leakage by 37% and MDA accumulation by 52% on average, whereas DIECA exacerbated stress-related damage. WGS achieved 16.24&#x2013;16.26&#xd7; coverage and identified 2.73&#x2013;2.78&#xa0;million SNPs, 378&#x2013;382k InDels, 25&#x2013;26k SVs, and 7.2&#x2013;7.9k CNVs. Twenty genes containing sequence variants showed transcriptional responses under cold stress that were significantly correlated with mutation density (r&#x2009;=&#x2009;0.62, P&#x2009;<&#x2009;0.01). One gene, XM_018985465.2, which lacked SNPs in &#x2018;Liaoning No.8&#x2019;, was expressed 4.2 times more in this variety, suggesting cis-regulatory influence. These findings highlight the role of jasmonic acid signaling in enhancing cold tolerance in walnut and offer genomic insights into its underlying adaptive mechanisms.

Juglans↗
PubMed1994

Cold (0 degree C) ischaemic tolerance of latissimus dorsi free flaps in rats: a macroscopic and morphological study.

The purpose of this study was to define the cold (0 degree C) ischaemic tolerance (CIT) of the latissimus dorsi free flap in inbred rats. Flaps were isolated, stored at 0 degree C for periods of time ranging from 0 to 120 hr and then revascularised and reperfused for 14 days. Thereafter the CIT was assessed macroscopically, and by light microscopy. Electron microscopy was performed in flaps after 0 and 24 hr of reperfusion following a cold ischaemic interval ranging from 0 to 120 hr. From this preliminary study, it was concluded that the CIT was 48-72 hr.

Animals↗
PubMed2004

CBF2/DREB1C is a negative regulator of CBF1/DREB1B and CBF3/DREB1A expression and plays a central role in stress tolerance in Arabidopsis.

CBF/DREB1 (C-repeat-binding factor/dehydration responsive element-binding factor 1) genes encode a small family of transcriptional activators that have been described as playing an important role in freezing tolerance and cold acclimation in Arabidopsis. To specify this role, we used a reverse genetic approach and identified a mutant, cbf2, in which the CBF2/DREB1C gene was disrupted. Here, we show that cbf2 plants have higher capacity to tolerate freezing than WT ones before and after cold acclimation and are more tolerant to dehydration and salt stress. All these phenotypes correlate with a stronger and more sustained expression of CBF/DREB1-regulated genes, which results from an increased expression of CBF1/DREB1B and CBF3/DREB1A in the mutant. In addition, we show that the expression of CBF1/DREB1B and CBF3/DREB1A in response to low temperature precedes that of CBF2/DREB1C. These results indicate that CBF2/DREB1C negatively regulates CBF1/DREB1B and CBF3/DREB1A, ensuring that their expression is transient and tightly controlled, which, in turn, guarantees the proper induction of downstream genes and the accurate development of Arabidopsis tolerance to freezing and related stresses.

Arabidopsis↗
PubMed1989

Pain avoidance in rheumatoid arthritis.

Forty-eight patients with rheumatoid arthritis were compared to 52 pain-free controls in terms of tolerance/avoidance and rated intensity of cold pressor pain. The patients had lower thresholds and tolerated the cold pressor pain for a shorter period, although not significantly so. However, the patients rated the novel nociceptive cold stimulus as significantly more painful. The results demonstrate that arthritis patients report novel pain experiences as being more painful, which necessitates special attention to their post-operative analgesic demands needs. Tolerance/avoidance of the cold pressor pain had different correlates in the more and less chronic patient groups, and was respectively related to the affective and sensory qualities of the pain stimulus. The results confirmed qualitative similarities between different chronic pain populations, suggesting that chronicity of the pain problem may be a more important factor in determining pain experience and pain-related behaviours than the specific locus of the pain.

Adult↗
PubMed2002

Quantitative and qualitative perceptual analysis of cold dysesthesia and hyperalgesia in fibromyalgia.

Somatosensory perception thresholds, perceived intensity, and quality of perceptions were assessed in 20 women with fibromyalgia syndrome (FMS) and in 20 healthy age-matched female controls. All patients and controls scaled perceived intensity and described perceived quality of randomized thermal (Thermotest) and tactile (von Frey filaments) stimulation. Perceived intensity was scaled by free-number magnitude estimation and interindividual comparability was accomplished by Master Scaling. Perceived quality was assessed by choosing verbal descriptors from a list. Thenar was used as a reference for each modality tested. All patients were able to reliably scale perceived intensity at thenar, as well as in pain-affected body areas. Perception thresholds for cold pain, heat pain, cold-pain tolerance and heat-pain tolerance were significantly lower in patients than controls. For cold and tactile stimulation, the master scaled perceived intensities were significantly higher in patients' pain-affected areas, whereas for warmth/heat stimulation, the intensities were significantly lower. In the qualitative perceptual analysis the most striking and significant finding was the aberration of cold-evoked perceptions in all patients: most stimuli in the range of 30-10 degrees C were reported as heat or other paresthetic or dysesthetic perceptions. The perceptual quality of warmth, and of touch, did not differ from the controls. Another aberration was observed in the nociceptive range of thermal and of tactile stimulation as significantly more frequent pain-related descriptors than in controls. This indicates a general nociceptive facilitation in addition to the lower thermal pain thresholds. The combination of cold hyperesthesia, cold dysesthesia, and multimodal hyperalgesia suggests a selective pathophysiology at a particular level of integration, possibly in the insular cortex. It is suggested that the aberrations revealed by the supraliminal sensory evaluation may be generic for FMS. Particularly, the aberrations established in all patients for perceived quality and intensity in the cold sensory channel may be an additional diagnostic criterion.

Adult↗
PubMed1988

Tracheal tubes in cold stress.

During rescues in cold climates, plastic tracheal tubes have fractured because of cold stress or mishandling. Susceptibility of rubber and plastic tracheal tubes to cold stress was tested in a climate chamber. Plastic tubes became stiffer when chilled, had greater resistance to reshaping and were more sensitive to shock and manipulation. They also need protection against cold and shock during transport. Rubber tubes were more tolerant of cold stress. Very cold rubber and plastic tubes may induce tissue damage. Rewarming to a nondangerous temperature was shown to be a quick procedure. It is suggested that the rescuer's own body heat be used.

Cold Climate↗
PubMed2026

Genome-Wide Characterization of the ScLOR Gene Family in Wild Tomato Solanum lycopersicoides Reveals ScLOR16 as a Negative Regulator of Cold-and Drought-Stress Tolerance.

The LOR (LURP-one related) gene family encodes proteins containing conserved LOR domains; however, its functions in plant abiotic stress responses remain largely unexplored. In this study, we systematically identified and characterized the LOR gene family in the stress-tolerant wild tomato Solanum lycopersicoides using comprehensive bioinformatic analyses and conducted functional validation of the candidate gene ScLOR16. A total of 19 ScLOR members were identified and classified into eight phylogenetic subgroups. Numerous cis-acting elements associated with responses to abscisic acid (ABA), cold, and drought, including ABRE, LTR, and MBS, were detected in the promoter regions, suggesting that the ScLOR family may be broadly involved in ABA-mediated stress signaling pathways. RT-qPCR analysis revealed that ScLOR16 expression was significantly induced by both cold and drought treatments. Subcellular localization assays demonstrated that ScLOR16 is localized in both the nucleus and cytoplasm. Virus-induced gene silencing (VIGS) was subsequently employed to generate ScLOR16-silenced plants. Following 24 h of cold treatment at 4 &#xb0;C and four days of drought stress, ScLOR16-silenced seedlings exhibited significantly less severe wilting symptoms than empty-vector controls. Physiological analyses showed that silenced plants exhibited enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, increased proline accumulation, and decreased thiobarbituric acid-reactive substances (TBARS) content. Collectively, these results indicate that reduced ScLOR16 transcript levels are associated with enhanced cold and drought tolerance, accompanied by alterations in antioxidant defense and osmoprotection-related physiological markers. This study yields new insights into the evolution and stress-related functions of the ScLOR family.

LOR gene family↗
PubMed2004

[Arabidopsis CBF1 in plant tolerance to low temperature and drought stresses].

Since it was established that the alteration in gene expression occur during cold acclimation, a major goal in cold acclimation research has been to identify cold-responsive genes and to determine whether they play roles in freezing tolerance. Many cold-regulated genes (COR) were isolated and characterized in Arabidopsis and other cold tolerant plant species. Studies on regulation of COR in Arabidopsis have resulted in the discovery of a family of transcriptional activators, of which, CBF1, a member of the gene family, controls expression of a battery of COR in Arabidopsis and other cold tolerant plant species. During recent years, CBF-like genes were found in the genomes of chilling-sensitive plant species such as tomato and maize. Over-expression of Arabidopsis CBF1 confers elevated tolerance to chilling and drought stresses in transgenic tomato. These results promote our effort to identify and characterize CBF-like genes to improve tolerance of chilling-sensitive plant species to chilling and drought stresses.

Acclimatization↗
PubMed2002

The influence of athletic status and gender on experimental pain responses.

To examine the role of athletic status and gender on experimental pain responses, 24 athletes (12 male, 12 female) and 24 nonathletes (12 male, 12 female) participated in 3 experimental pain tasks. After a series of psychologic inventories and demographic questionnaires, pressure pain thresholds (4 sites: pectoralis, trapezius, biceps, quadriceps), ischemic pain threshold and tolerance (lower arm), and cold pressor pain threshold and tolerance (lower arm) were assessed. No significant overall effects of athletic status or gender were identified for measures of pressure pain threshold. No group differences emerged for ischemic pain threshold. Athletes demonstrated significantly higher tolerance for ischemic pain, and cold pressor pain threshold and tolerance were higher among athletes than nonathletes. Overall analyses indicated higher pain thresholds and tolerance for cold pain among men than among women. A final interview found that many participants who approached the upper limits of these pain tasks reported using a competitive coping strategy.

Journal Article↗
PubMed2003

The sfr6 mutant of Arabidopsis is defective in transcriptional activation via CBF/DREB1 and DREB2 and shows sensitivity to osmotic stress.

The sfr6 mutant of Arabidopsis displays a deficit in freezing tolerance after cold acclimation. We previously observed that the transcripts of three cold-, ABA- and drought-inducible genes, each having a C-repeat motif or the drought-responsive element (CRT/DRE) in its promoter, failed to normally accumulate in this mutant. We now report that the effects of sfr6 upon transcript levels are reflected in the levels of the encoded proteins, confirming that the cold-inducible protein expression is affected by the sfr6 mutation. Using microarray analysis, we found not only that this effect may be general to cold-inducible genes with CRT/DRE promoter elements, but also that it extends to some other genes whose promoters lack a CRT/DRE element. The role of the CRT/DRE has been empirically tested by use of a synthetic promoter, confirming that the CRT/DRE is sufficient to confer the sfr6 effect upon expression. Tolerance of osmotic stress was also found to be reduced in sfr6, consistent with a role in osmotic stress tolerance for the cold-, ABA- and drought-inducible genes whose expression is affected by the sfr6 mutation.

Abscisic Acid↗
PubMed2004

Sucrose consumption enhances the analgesic effects of cigarette smoking in male and female smokers.

RATIONALE: Nicotine has analgesic actions in experimental animals and humans. Moreover, the analgesic properties of nicotine in experimental animals are increased by intake of sweet-tasting nutritive fluids. It is important to determine if the effects of diet on nicotine-induced analgesia are limited to experimental animals, or if these effects can be translated from the laboratory to clinical research situations. OBJECTIVE: This study investigated whether intake of a sweet-tasting sucrose solution would enhance the pain relieving actions of nicotine, administered in the form of cigarette smoking, in male and female college-aged students. The effects of smoking and sucrose intake on mood were also examined. METHOD: Using the cold pressor test, pain thresholds and pain tolerance were determined in 24 male and 25 female smokers. Each participant was tested 4 times. On 2 of the test days, participants drank a sucrose-containing beverage, and on 2 of the days, drank water. Twenty-five minutes later, participants either smoked a cigarette or did not smoke. Participants were tested 5 min later for their responses on the cold pressor test. To determine if mood was altered by smoking or sucrose intake, the Profile of Mood Scale was administered immediately preceding and following experimental manipulations. RESULTS: Cold threshold and cold tolerance were greater when participants were allowed to smoke than when they were not allowed to smoke. While men and women responded in a similar manner to the experimental manipulations, men displayed significantly greater cold threshold and cold tolerance than women. Sucrose consumption augmented the effects of smoking on cold threshold, but not on cold tolerance. Men reported feeling significantly more vigorous and less angry, and women reported feeling significantly less tense after they had smoked than when they had not smoked. Sucrose consumption did not alter self-reports of mood in either men or women. CONCLUSION: These findings suggest that sucrose augments the analgesic properties of nicotine in humans, as well as in experimental animals, and suggest that diet could serve as an adjunct in the control of pain.

Adolescent↗