Experimental observations of coronary blood flow using the thermographic camera.
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Animals↗
SEARCH · PubMed Health
Results for “Cold Temperature”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Physical therapy improves venous hemodynamics in cases of primary varicosity: results of a controlled study.
Physical factors are known to influence hemodynamics in the veins of the lower extremities. In a controlled, randomized study the authors investigated the effects of combined physical therapy on varicose veins. Over a twenty-four-week period a treatment group consisting of 12 persons exercised under the supervision of a therapist twice a week for sixty minutes. This included muscle and joint activation by means of externally applied compression and cold-temperature stimuli (ie, thermosteresis). They also exercised once a day without supervision for fifteen minutes. During the same period a control group of 12 persons underwent the same measurements but no treatment. In the treatment group venous capacity decreased by an average of 16% from 4.9 +/- 0.3 (sd) mL/100 mL tissue to 4.1 +/- 0.4 (P < 0.005, U-test) while in the control group it remained practically unchanged at 4.8 +/- 0.4 vs 5.0 +/- 0.3. Venous refilling time in the lower extremities also increased in the treatment group, half refilling time rising from 7.8 +/- 1.0 to 11.3 +/- 0.9 seconds (P < 0.001) and total refilling time from 17.0 +/- 1.4 to 25.7 +/- 2.1 seconds (P < 0.001); these parameters remained virtually unchanged in the control group, with half refilling time dropping slightly from 7.7 +/- 1.1 to 7.1 +/- 1.3 seconds and total refilling time from 18.3 +/- 1.7 to 16.3 +/- 1.9 seconds. Patient self-rating scores obtained by use of a standardized questionnaire administered at baseline and at the end of week 24 improved in the treatment group only. The combined physical therapy was thus shown to be of long-term therapeutic value, improving venous function and reducing patients' symptoms. These findings indicate that for the further development of this combined treatment regimen it would be useful to identify the individual factors contributing to its efficacy and evaluate them separately.
Adult↗
Vesicular and ulcerative dermatopathy resembling superficial necrolytic dermatitis in captive black rhinoceroses (Diceros bicornis).
The histopathology, clinical presentation, and epidemiology of a cutaneous and oral mucosal disease affecting 40 black rhinoceroses (Diceros bicornis) at 21 zoological parks (50% of the captive US population) were investigated. Twenty-seven biopsies were examined from recent lesions, and clinical information was available from 127 episodes. The cutaneous lesions began as plaques that progressed to vesicles, bullae, or ulcers. Lesions waxed and waned in individual cases. Lesions were predominantly bilaterally symmetrical, affecting pressure points, coronary bands, tips of the ears and tail, and along the lateral body wall and dorsum. Oral lesions were first noticed as ulcers and were present on the lateral margins of the tongue, palate, and mucocutaneous junctions of the lips. All recent lesions had similar histopathologic findings of prominent acanthosis, hydropic degeneration of keratinocytes in the stratum spinosum, spongiosis, intraepithelial vesicles, and parakeratosis without dermal inflammation. Chronic lesions were ulcerated. No pathogens were identified by culture or electron microscopy. Most episodes coincided with stress events (transportation, sudden cold temperatures, intraspecific harassment, estrus, advanced pregnancy) or concurrent diseases (toxic hepatopathy, hemolytic anemia, respiratory or urinary tract infections). Affected rhinoceroses usually were lethargic and had weight loss. Affected rhinoceroses also had lower hematocrit, serum albumin, and cholesterol values than captive healthy or wild rhinoceroses. The clinical patterns and histopathologic findings are similar to those of superficial necrolytic dermatitis in dogs and necrolytic migratory erythema in humans. The high prevalence of this skin disease in captive black rhinoceroses under many circumstances suggests that their epidermis is acutely sensitive to any disruption of metabolic homeostasis. We propose that metabolic changes secondary to a stress response from maladaptation or nutritional inadequacy of captive diets may contribute to the development of this disease in rhinoceroses without hepatopathies.
Animals↗
Disabling foot cramping in a runner secondary to paramyotonia congenita: a case report.
An 18-year-old male runner was referred to the authors' clinic with a 1-year history of cramping left foot pain. His symptoms developed insidiously when he increased his training, with an onset of severe left foot pain and tightness that would develop after about 20 minutes of exercise. The more he continued to run, the more the symptoms were aggravated and evolved to the toes curling with intrinsic muscle spasm. This symptom was easily provoked when he was exposed to cold temperature. A family history of similar symptoms was revealed in his sister and uncle. Physical examination including neurologic examination was normal. Diagnostic workup revealed generalized myotonia. According to the history, physical examination, and diagnostic workup, his diagnosis was considered to be most compatible to paramyotonia congenita. He was given phenytoin, which lessened his symptoms and allowed him to continue running with minimal symptoms, but he stopped running because he was not able to maintain mileage high enough to compete successfully.
Adolescent↗
Effect of precooling on physical performance in multiple sclerosis.
Many individuals with MS experience heat sensitivity that may be associated with transient increases in the frequency of clinical signs and symptoms. Although physical activity may be beneficial for those with MS, induced thermal loads may preclude participation in exercise and other daily activities. This project was designed to evaluate the effects of precooling on physical function. Six thermosensitive MS patients were studied. Participants performed a graded exercise test to determine maximal oxygen uptake (VO2max) on a combined arm-leg ergometer. Thermal load was induced by 30 min of exercise under noncooled and precooled conditions at a workrate corresponding to 60% VO2max. Precooling consisted of 30 min lower body immersion in 16 - 17 degrees C water. Fatigue and 25-ft walk performance were assessed before, immediately after, and 30 min following exercise. No treatment differences in VO2 were observed. Rectal temperature, heart rate, and rating of perceived exertion (RPE) were significantly lower during the precooled exercise trial compared to the noncooled trial. Immediately following exercise, 25-ft walk performance and fatigue scores showed significantly greater deterioration in the noncooled condition. Precooling was effective in preventing gains in core temperature with physical work and may allow heat-sensitive individuals with MS to exercise with greater physical comfort.
Adult↗
Changes in sensory and pain perception thresholds after linear polarized near-infrared light radiation in the trigeminal region.
Linearly polarized light in the near-infrared portion of the spectrum has recently been associated with a variety of musculoskeletal disorders including temporomandibular disorders. The purpose of this study was to determine whether short-term linearly polarized near-infrared light radiation in the trigeminal region affects sensory and pain perception thresholds in the trigeminally mediated region and in the cervically mediated region of normal subjects. Thirty-five normal female volunteers participated in this study. Each subject received an 8-minute course of irradiation in the right cheek, and sensory/nociceptive perception thresholds were compared before and immediately after the irradiation in the right cheek and the right forearm. As a result, this study demonstrated a significant elevation of the heat-induced pain threshold in both regions and a tendency for the warm sensation threshold to elevate in the cervical region. In addition, a significant increase in vibratory sensitivity was observed in the trigeminal region. In conclusion, our results provided additional evidence that the warming sensation has a negative feedback influence on heat pain intensity in humans, and provides a theoretical basis for the application of linear polarized near-infrared light radiation to the trigeminal region.
Adult↗
Brain energetics and tolerance to anoxia in deep hypothermia.
The remarkable time-resolution enhancement by deep lethargic hypothermia (15 degrees C rectal temperature, "cold narcosis," "anesthesia by internal cold") of metabolic events in the rat brain after oxygen deprivation has been exploited to monitor metabolic changes by in vivo (31)P-NMR. A correlation was established between the bioenergetic status of the brain and physiological descriptors of tolerance (survival and revival times) determined in parallel experiments with large series of animals. Spectral peak integrals were transformed into absolute concentrations by comparison to biochemically determined time series of data obtained in freeze-trapping experiments conducted under identical conditions. Serial spectra were used to reconstruct the time-course kinetics of intracellular brain pH and of concentration changes of inorganic phosphate, phosphocreatine, ATP, and ADP. Both the biochemical and NMR time series of data were simultaneously fitted by a set of exponential kinetic equations accounting for relationships imposed by the Lohmann and adenylate kinase reactions. Depletion profiles were then computed for a number of descriptors of brain energy status (energy charge, phosphorylation potential, total adenylate, and primary energy stores expressed as the sum of high-energy phosphate-bond equivalents). The results contribute to the understanding of the role of brain energetics in tolerance to oxygen deprivation.
Adenosine Diphosphate↗
Thyrotropin secretion in genetically obese rats.
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Animals↗
Myotonia and the muscle chloride channel: dominant mutations show variable penetrance and founder effect.
The delayed relaxation or sustained contraction of skeletal muscle-myotonia-is frequently seen in myotonic dystrophy and sodium channelopathies (hyperkalemic periodic paralysis, paramyotonia congenita). Many cases of congenital myotonia without other clinical symptoms have been associated with mutations in the muscle chloride channel gene. Most cases reported to date show a recessive inheritance pattern, with loss of function of the corresponding protein. Six families have been reported with dominantly inherited myotonia and mutations of the chloride channel gene. Here we report clinical and molecular data on 38 family members from four new families with dominantly inherited myotonia congenita. Three families show a previously characterized G230E mutation, and we show that these three share a common affected ancestor despite living in different regions of the United States (linkage disequilibrium). One Italian family is shown to have a novel dominant mutation-I290M. This is the sixth mutation identified in Thomsen's myotonia. Genotype/phenotype correlations in these four families showed that both of the dominant mutations resulted in a mild clinical picture in 90% of the patients, and no symptoms in 10% of mutation-positive patients. The EMG was the clinical feature that most closely correlated with mutation data; however, 3 of 16 (19%) mutation-positive patients tested negative by electromyography at least once, and 1 (6%) tested negative despite multiple tests. Only about half (55%) of the mutation-positive patients tested positive for percussion myotonia. Most of the clinically symptomatic individuals stated that cold temperatures and stress substantially worsened their myotonia. Our data show that dominantly inherited Thomsen's myotonia is most often a very mild disorder that shows considerable clinical heterogeneity.
Adult↗
Telophase disc: a new mammalian mitotic organelle that bisects telophase cells with a possible function in cytokinesis.
We have discovered a novel mitosis-specific human autoantigen that arises at the centromeres of prophase chromosomes, but ultimately participates in formation of an organelle that bisects the cell at late anaphase and during telophase. The organelle, discernible as a three-dimensional disc by confocal microscopy, encompasses the entire midzone diameter, and its distribution survives disassembly of interpolar microtubules by cold temperature treatment and detergent lysis of cells. Cytokinetic furrow contraction proceeds normally in dihydrocytochalasin B (DCB)-treated cells, and antigen distribution in the furrow is unaltered. In DCB, the furrow retracts in early interphase, coincident with loss of normal membrane association with the disc, resulting in the formation of binucleate cells. The midzone disc in both drug-treated and normal cells is present at the correct time and position to play a central role in cytokinesis. By immunocytochemistry, the disc appears to contain myosin but not actin. The position of the disc and the possible presence of myosin suggest that cytokinesis may involve the interaction of the disc organelle with actin in the cell cortex to produce cleavage in mammalian cells.
Actins↗
Muscle remodeling in relation to blood supply: implications for seasonal changes in mitochondrial enzymes.
We investigated if seasonal changes in rainbow trout muscle energetics arise in response to seasonal changes in erythrocyte properties. We assessed if skeletal muscle mitochondrial enzymes changed (1) acutely in response to changes in erythrocyte abundance, or (2) seasonally when we altered the age profile of erythrocytes. Rainbow trout were treated with pheynylhydrazine, causing a 75% reduction in hematocrit within 4 days. After erythropoiesis had returned hematocrit to normal, treated and control fish were subjected to a seasonal cold acclimation regime to assess the impact of erythrocyte age on skeletal muscle remodeling. Anemia (i.e. phenylhydrazine treatment) did not alter the specific activities (U g(-1) tissue) of mitochondrial enzymes in white or red muscle. Anemic pretreatment did not alter the normal pattern of cold-induced mitochondrial proliferation in skeletal muscle, suggesting erythrocyte age was not an important influence on seasonal remodeling of muscle. Anemia and cold acclimation both induced a 25-30% increase in relative ventricular mass. The increase in relative ventricular mass with phenylhydrazine treatment was accompanied by a 35% increase in DNA content (mg DNA per ventricle), suggesting an increase in number of cells. In contrast, the increase in ventricular mass with cold temperature acclimation occurred without a change in DNA content (mg DNA per ventricle), suggesting an increase in cell size. Despite the major increases in relative ventricular mass, neither anemia nor seasonal acclimation had a major influence on the specific activities of a suite of mitochondrial enzymes in heart. Collectively, these studies argue against a role for erythrocyte dynamics in seasonal adaptive remodeling of skeletal muscle energetics.
Acclimatization↗
The effects of behaviourally relevant temperatures on mechanosensory neurones of the grasshopper, Schistocerca americana.
Grasshopper mechanosensory hair neurones respond to displacement of their associated hairs in a temperature sensitive manner: comparable increases in the number of spikes per stimulus result from increases in temperature with constant stimulus strengths and from increasing stimulus strengths at constant temperature. It is therefore not obvious that neurones in the CNS which receive inputs from mechanosensory hairs would be able to distinguish between these two parameters. The temperatures which populations of mechanosensory hairs on the thorax, head and tarsus experienced were measured in freely moving animals. Animals in thermally heterogeneous environments spent 90% of the accounted time in locations where thoracic temperatures of 32-44 degrees C were maintained (the behaviourally 'preferred' range). Head temperatures covered a wider range, and tarsal temperatures the widest. Different populations of mechanosensory hair neurones exhibited different sensitivities to temperature. Thoracic hair neurones were significantly more temperature sensitive than one of the two populations of head hairs studied, and tarsal hairs exhibited a pronounced temperature compensation in the behaviourally 'preferred' range. Wind sensitive head hairs, however, showed exceptionally high temperature sensitivities. There is a negative correlation between the temperature sensitivity of a population of mechanosensory hair neurones and the temperature variability to which those neurones are normally exposed. Implications of this correlation for the central interpretation of mechanosensory input are considered.
Animals↗
Energy metabolism during embryonic development and larval growth of an Antarctic sea urchin.
Developmental energetics of an Antarctic sea urchin, Sterechinus neumayeri, were quantified to describe the physiological bases underlying ontogenetic changes in metabolic rate at extreme cold temperatures (-1.5 degrees C). Rates of development from a four-arm to a six-arm larval stage were not affected by food availability. The respiratory cost of development to the six-arm larval stage (day 60) was 14.0 mJ for fed larvae and 8.2 mJ for unfed larvae. We observed three phases of metabolic regulation during development. During embryogenesis (day 0-22), increasing metabolic rates were proportional to increases in cell numbers. During early larval development (day 22-47), the differences in respiratory rate between fed and unfed larvae were not accounted for by cell number, but by cell-specific metabolic rate (respiratory rate normalized to DNA content). Once an advanced larval stage had been reached (day 47-60), cell-specific respiratory rate and mitochondrial densities (citrate synthase activity normalized to DNA content) were more equivalent between fed and unfed larvae, suggesting that size-specific metabolic rates were determined at a level of physiological regulation that was independent of cell numbers or feeding history.
Animals↗
Role of MerT and MerP from Pseudomonas K-62 plasmid pMR26 in the transport of phenylmercury.
To investigate the individual role of MerT and MerP encoded by Pseudomonas K-62 pMR26 in the transport of phenylmercury, a series of mutants with a specific point mutation in merT and/or genetic deletion in merP were constructed and transformed into Escherichia coli XL1-Blue. Transport of phenylmercury across the cytoplasmic membrane of E. coli mediated by MerT and MerP was inhibited by NaCN and by cold temperatures. Deletion of merP reduced, but did not completely abolish the C6H5Hg+-hyperuptake and -hypersensitive phenotypes suggesting that transport of phenylmercury into the cytoplasm of E. coli is still occurring. Mutations of the vicinal cysteine residues (Cys24 and Cys25) in the first transmembrane region of MerT to serine caused complete loss of Hg2+-hyperuptake and -hypersensitivity, whereas the mutations did not affect the C6H5Hg+-hyperuptake and -hypersensitive phenotypes. In addition, no additive effect on the C6H5Hg+-hyperuptake and -hypersensitive phenotypes was found, when mutations of the two cysteines in MerT to serine were further introduced in the merP-deleted mutants. These results clearly demonstrated that the vicinal cysteine residues of MerT are not involved in the transport of C6H5Hg+, but indeed are involved in the transport of Hg2+ as previously reported.
Bacterial Proteins↗
Regulation of the peripheral body temperature by foods: a temperature decrease induced by the Japanese persimmon (kaki, Diospyros kaki).
We investigated whether the ingestion of the Japanese persimmon (kaki, Diospyros kaki) could lower the human peripheral body temperature. It was found that the temperatures recorded at the foot and wrist were depressed after kaki consumption compared to after the same amount of water consumption. The effects of ingesting freeze-dried kaki and eating a cookie (as its nutritional counterpart) containing the same amount of carbohydrate, protein, fat, and water were compared. A similar temperature-reducing effect of kaki was observed. The recovery of finger temperature after soaking the finger in ice-cooled water was also studied. The temperature recovery was delayed after kaki consumption. It was thus quantitatively demonstrated that ingesting kaki indeed had the effect of lowering (or repressing the rise) of the peripheral human body temperature, as has been traditionally believed in China for many hundreds of years.
Adult↗
Flowering: a time for integration.
Flowering time is under the control of multiple environmental cues such as photoperiod and exposure to cold temperatures (vernalization). A few regulators named integrators of flowering time signals (LEAFY, SOC1 /AGL20 and FT ) integrate inputs from the different flowering cascades and convey the resulting outcome to floral meristem identity genes at the shoot apex. Here we review the current knowledge about the expression of integrators, their mode of action, their potential target genes and the nature of their mutual interactions. We emphasize the questions that have been generated by recent progress in this field and that remain to be addressed.
Arabidopsis↗
Improvement of semen quality by nocturnal scrotal cooling and moderate behavioural change to reduce genital heat stress in men with oligoasthenoteratozoospermia.
A questionnaire assessing factors that might cause an increase in scrotal temperature was completed by patients with reproducible oligoasthenoteratozoospermia of idiopathic nature or caused by varicocele. Evaluation by means of a grading scale revealed increased scrotal heat stress in oligoasthenoteratozoospermic patients compared with normozoospermic men (P < 0.01). In addition, long-term determination of 24 h scrotal temperature profiles showed that compared with semen donors, oligoasthenoteratozoospermic patients frequently had scrotal temperatures above 35.5 degrees C despite the same environmental temperatures (P < 0.05). In 88% of cases, maximum scrotal temperatures were measured during rest or sleep phases, whereas minimum values were recorded during physical activity or frequent change of position. Nocturnal scrotal cooling by means of an air stream resulted in a decrease in scrotal temperature of approximately 1 degrees C. Furthermore, a highly significant increase in sperm concentration (P < 0.0001) and total sperm output (P < 0.0001) was achieved after nocturnal scrotal cooling for 12 weeks together with a moderate decrease in factors leading to genital heat stress. A significant improvement in sperm motility (P < 0.05) and sperm morphology (P < 0.05) was also observed, but this improvement was markedly less pronounced than the changes in sperm concentration. This study shows the importance of genital heat stress as a cofactor in fertility impairment in men and indicates nocturnal scrotal cooling as a therapeutic option.
Behavior Therapy↗
zds1, a novel gene encoding an ortholog of Zds1 and Zds2, controls sexual differentiation, cell wall integrity and cell morphology in fission yeast.
While screening for genes that reverse the sporulation-deficient phenotype of the ras1delta diploid Schizosaccharomyces pombe strain, we identified zds1. This gene shares sequence homology with the ZDS1 and ZDS2 genes from Saccharomyces cerevisiae, which appear to be involved in multiple cellular events. Expression of Zds1 in ras1delta diploid cells elevated their sporulation rate from 0.3 to 11.2%. Expression of the Zds1 C-terminal region increased the sporulation rate further (to 21.9%) while introduction of the Zds1 N-terminal region had no effect. zds1 expression did not induce sporulation in strains with mutations in genes participating in the downstream MAP kinase cascade. The zds1-disrupted strain is sensitive to CaCl2, and this effect is suppressed by the C-terminal region of Zds1. The growth of the zds1delta strain is markedly inhibited by cold temperatures, while its viability decreased in the stationary phase. Moreover, the zds1delta strain is round in shape and very sensitive to zymolyase, and its cell wall becomes thicker than that of wild type. Thus, zds1 must be required to maintain cell wall integrity. The Zds1-GFP fusion protein localized to the cytosol, the septum, and the cell cortex. Its localization in the septum was dependent on its C-terminal region. Overexpression of the C-terminal region of Zds1 induced multi-septa and abnormal zygotes. We propose that the C-terminal region is the functional domain of Zds1 while the N-terminal region is a negative regulatory region. Thus, Zds1 is involved in multiple cellular events in fission yeast, including sexual differentiation, Ca2+ tolerance, cell wall integrity, viability in the stationary phase, and cell morphology.
Adaptor Proteins, Signal Transducing↗