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PubMed1982

Effect of atmospheric ammonia on laying hen performance.

In periods of extremely cold weather, energy conservation in a pit-type laying house usually results in a restricted ventilation rate and an increase in air pollutants particularly ammonia. Results show that 200 ppm ammonia for 17 days causes a significant loss in percent egg production and the hens lose a significant amount of weight with a reduced feed intake. Although not satisfactory, it appears that lesser amounts of ammonia (100 ppm) can be tolerated for short periods without an immediate drastic loss in laying performance if a choice has to be made between frozen waterers and cold stress versus atmospheric ammonia in the laying house.

Ammonia↗
PubMed1985

Tolerance to nitrous oxide in volunteers.

Nociception and loss of awareness during exposure to anaesthetic concentration of nitrous oxide (N2O) were studied in eight male medical students. The cold water nociception test, where a hand is immersed in 0 degree C stirred water, was used for measurement of nociception. At irregular intervals an auditory command was given to oppose two fingers, and this served to monitor consciousness. The selected inspiratory concentration of N2O used per individual was sufficient to induce a loss of consciousness for more than 2.5 min, within 10 min of exposure to N2O. This concentration of N2O varied from 60% to 80%. The experimental exposure to N2O lasted 3 h. In all volunteers significant antinociception was observed within 2 min of exposure to N2O. The maximal analgesic effect was observed between 20 and 30 min of exposure to N2O. The analgesic effect of N2O gradually decreased and was absent in all eight volunteers within 150 min. Two volunteers regained consciousness at 77 and 91 min of exposure, whilst still breathing 60 and 80% N2O. These results show that tolerance to antinociceptive effects of N2O in man rapidly develops and that awareness may occur in some volunteers during prolonged exposure to N2O.

Adult↗
PubMed2001

Reduced pain tolerance during and after pregnancy in women suffering from fear of labor.

Pain tolerance in women suffering and not suffering from fear of labor during and after pregnancy were compared. Twenty women with labor fear and 20 control women were subjected to a cold pressor test (CPT) on average 1 month before delivery and 9 months later. Half the volunteers were nulliparous and half parous. Pain endurance time (PET) and intensity of pain (Visual Analogue Scale, VAS) during CPT was assessed. Patients in the fear group tolerated CPT for a significantly shorter time than did women without fear both in pregnancy (154.8+/-109.9 s vs. 282.5+/-60.1 s (mean+/-SD), P<0.001), and in the postpartum period (128.6+/-111.7 s vs. 279.6 +/-60.3 s, P=0.002). Those with labor fear experienced CPT as significantly more painful than did the controls both during pregnancy (VAS 6.68+/-1.9 vs. 3.78+/-2.0 (mean+/-SD), P<0.001) and after (VAS 7.73+/-1.5 vs. 5.92+/-3.0, P=0.04). PET and VAS values correlated during pregnancy (r=-0.62, P<0.001), but not after pregnancy (r=-0.30, not significant). Parity was not associated with either PET or VAS scores. As a rule, pain in all women during CPT was regarded to be lower during pregnancy than after pregnancy (VAS 4.87+/-2.4 vs. 6.60+/-2.6, P=0.001). Patients with fear of labor were characterized by pain intolerance also in circumstances other than labor. This fact may indicate enhanced sensitivity to pain-causing mechanisms in women who develop fear of labor.

Adult↗
PubMed2004

After images and pain tolerance: a descriptive study on their interrelationship.

After images are based on physiological processes, they can also be treated as subjective phenomena with a psychological meaning. This statement also applies to pain. The basic working hypothesis of this study concerned the relationship between the two phenomena. Forty-one respondents (23 females, 18 males, age range 20-45 years) were given the Cold Pressor Test and the Serial After Image Technique. The data analysis was done by means of cross-tables and an exploratory optimal scaling program (OVERALS). Three pain tolerance groups (low, medium, high) could be differentiated fairly well on the basis of the after image characteristics of the respondents. Pain intolerant respondents more frequently had small and "immature" after images, whereas highly pain tolerant respondents had more large and "mature" after images. The implications of these results for a bio-psycho-social theoretical frame of reference for pain are discussed.

Adult↗
PubMed1986

Estimation of insulin sensitivity and glucose clearance from minimal model: new insights from labeled IVGTT.

The "minimal model" of glucose disappearance provides noninvasive estimates of insulin sensitivity and glucose effectiveness from an intravenous glucose tolerance test (IVGTT). However, this model does not allow the separation of glucose production from utilization. To overcome this limitation, labeled glucose was injected along with cold glucose in six normal dogs, and both cold and labeled glucose time courses were monitored along with insulin concentration. A revised minimal model was fitted to tracer data to obtain new measures of insulin sensitivity (SI* = 6.41 +/- 0.91 10(-4) min-1 X microU-1 X ml-1) and fractional glucose clearance (SG* = 0.0092 +/- 0.0009 min-1). SG* was compared with a direct measure obtained by a hepatic arterial-venous difference technique, which yielded a value of 0.0097 +/- 0.0002, virtually identical to SG*, thereby validating the model estimate. When the original minimal model was identified from cold data, we obtained S1 = 4.52 +/- 1.39 and SG = 0.042 +/- 0.009. SI* and SG* were different from SI and SG, respectively. In particular SG overestimates fractional glucose clearance by approximately five times. The revised minimal model yields glucose disposal parameters SI* and SG* that are not affected by the confounding effect of insulin and glucose inhibition of glucose production. Limitations inherent in cold IVGTT and original minimal model are overcome by labeled IVGTT and the revised minimal model, while test simplicity remains.

Animals↗
PubMed1994

A Contrast of the Plasma Membrane Lipid Composition of Oat and Rye Leaves in Relation to Freezing Tolerance.

The lipid composition of the plasma membrane isolated from leaves of spring oat (Avena sativa L. cv Ogle) was vastly different from that of winter rye (Secale cereale L. cv Puma). The plasma membrane of spring oat contained large proportions of phospholipids (28.8 mol% of the total lipids), cerebrosides (27.2 mol%), and acylated sterylglucosides (27.3 mol%) with lesser proportions of free sterols (8.4 mol%) and sterylglucosides (5.6 mol%). In contrast, the plasma membrane of winter rye contained a greater proportion of phospholipids (36.6 mol%), and there was a lower proportion of cerebrosides (16.4 mol%); free sterols (38.1 mol%) were the predominant sterols, with lesser proportions of sterylglucosides (5.6 mol%) and acylated sterylglucosides (2.9 mol%). Although the relative proportions of individual phospholipids, primarily phosphatidylcholine and phosphatidylethanolamine, and the molecular species of these two phospholipids were similar in oat and rye, the relative proportions of di-unsaturated species of these two phospholipids were substantially lower in oat than in rye. The relative proportions of sterol species in oat were different from those in rye; the molecular species of cerebrosides were similar in oat and rye, with only slight differences in the proportions of the individual species. After 4 weeks of cold acclimation, the proportion of phospholipids increased significantly in both oat (from 28.8 to 36.8 mol%) and rye (from 36.6 to 43.3 mol%) as a result of increases in the proportions of phosphatidylcholine and phosphatidylethanolamine. For both oat and rye, the relative proportions of di-unsaturated species increased after cold acclimation, but the increase was greater in rye than in oat. In both oat and rye, this increase occurred largely during the first week of cold acclimation. During the 4 weeks of cold acclimation, there was a progressive decrease in the proportion of cerebrosides in the plasma membrane of rye (from 16.4 to 10.5 mol%), but there was only a small decrease in oat (from 27.2 to 24.2 mol%). In both oat and rye, there were only small changes in the proportions of free sterols and sterol derivatives during cold acclimation. Consequently, the proportions of both acylated sterylglucosides and cerebrosides remained substantially higher in oat than in rye after cold acclimation. The relationship between these differences in the plasma membrane lipid composition of oat and rye and their freezing tolerance is presented.

Journal Article↗
PubMed2003

[Effectiveness of three-stage rehabilitation of patients with chronic obstructive lung diseases].

AIM: To study the effectiveness of three-stage rehabilitation of patients with chronic obstructive lung disease (COLD). MATERIAL AND METHODS: An open randomized control trial included COLD patients divided into two groups. Group 1 patients have undergone three-stage rehabilitation: outpatient clinic-hospital-sanatorium, group 2 controls have undergone rehabilitation only in outpatient clinic. The condition of the patients was assessed by physical performance (bicycle exercise, 6-min walk test), external respiration function (spirography), tolerance to dyspnea (questionnaire) at the trial start and in 3, 6, 9, 12 and 18 months. Three-stage rehabilitation continued for 9 months. RESULTS: Positive changes in physical performance and dyspnea tolerance were more pronounced in three-stage rehabilitation. This trend persisted for 9 months and than positive results got worse. CONCLUSION: Three-stage rehabilitation of COLD patients is highly effective and should be an essential part of COLD treatment policy.

Humans↗
PubMed2006

The role of mood states underlying sex differences in the perception and tolerance of pain.

While sex differences in pain reporting are frequently observed, the reasons underlying these differences remain unclear. The present study examined sex differences in self-report and physiological measures of pain threshold and tolerance following the administration of two laboratory pain-induction tasks. The primary study aim centered on determining whether repeated exposure to such tasks would yield sex differences in terms of pain threshold and tolerance. In addition, it was hypothesized that if such differences did exist, negative mood states might account for changes in pain ratings, threshold, and/or tolerance in subsequent exposure to noxious stimuli. Recruited from a convenience sample, 66 participants (44 female and 22 male) were exposed to both thermal and cold noxious stimuli at three separate times, while psychophysiological and self-report data were collected. Because women outnumbered men 2:1, Fisher z transformations were performed to determine whether the observed associations between mood states and pain ratings differed. We found stronger associations between fatigue and thermal-heat pain ratings for men at their first and third exposure to the pain task compared to women (z = 2.11, P < 0.05; z = 3.14, P < 0.001, respectively). Results indicated that women evidenced greater pain tolerance than men on both a behavioral and physiological level; however, they reported greater pain severity than men. Fatigue was also found to be particularly important to reports of pain severity in men and pain tolerance in response to noxious stimuli for women. Possible pathways in which mood states influenced these endpoints are discussed.

Adult↗
PubMed2001

Mice lacking Ca(v)2.3 (alpha1E) calcium channel exhibit hyperglycemia.

To investigate the functional role of Ca(v)2.3 channel in glucose homeostasis, we performed in vivo glucose tolerance and insulin tolerance tests together with stress-induced glucose release tests using mice deficient in Ca(v)2.3 channel (Ca(v)2.3-/-). The Ca(v)2.3-/- mice were significantly heavier than wild-type mice. In glucose tolerance and insulin tolerance tests, Ca(v)2.3-/- mice showed a significantly higher blood glucose level compared to wild-type mice. However, stress-induced blood glucose changes in Ca(v)2.3-/- mice were similar to those in wild-type mice. These results suggest that Ca(v)2.3 channel plays a role in glucose homeostasis by reducing insulin sensitivity and that Ca(v)2.3-/- mice exhibit symptoms resembling non-insulin-dependent diabetes mellitus.

Animals↗
PubMedDate not supplied

[Carbohydrate and lipid metabolism in rats during adaptation to cold].

Cold adapted rats are shown to have glucose and fatty acids concentration in blood inchanged, lactate concentration increased and triglyceride concentration decreased against the control level. Glucose utilization rate in the tolerance test grows. Glycogen content falls, hexokinase and succinate dehydrogenase activity increases, glucose-6-phosphatase and NAD+-isocytratedehydrogenase activity decreases in the liver of experimental animals. The results indicate that utilization of carbohydrate and lipid substrates for thermogenesis is intensified in cold-adapted rats. The hypothesis is supported by the data of tests dealing with IPNA injection or with bringing the animals back under thermocomfortable conditions.

Adaptation, Physiological↗
PubMed1987

Generation of activated killer cells in tumor-bearing hosts.

Activated killer (AK) cells were generated in spleen-cell cultures derived from tumor-bearing hosts (TS) whereas, under the same conditions, cultured normal spleen cells (NS) gave little cytotoxicity. The AK effectors were primarily Thy1+, AGM1- and Lyt2- and thus were neither classic cytotoxic T lymphocytes (CTL) nor classic NK cells. These AK cells selectively killed tumor targets of different etiologic origins and did not kill concanavalin-A-induced lymphoblasts. The broad target-cell reactivity of these AK cells was also confirmed by cold target-inhibition experiments. Generation of AK cell correlated with interleukin-2 (IL-2) production, and the levels of AK cells generation paralleled those of IL-2 production. Furthermore, the generation of AK cells was blocked by the anti-IL-2 receptor monoclonal antibody (MAb) (alpha IL-2R), indicating that IL-2 was involved, and thus these AK cells were lymphokine-activated killer (LAK) cells. We previously showed that the expression of AGM1 on LAK precursors disappeared when they differentiated into LAK effectors, indicating that the activated LAK cells lacked AGM1. When examining the serologic phenotype of the LAK precursors in tumor-bearing hosts, we found that they lacked AGM1, which suggested that these LAK precursors were in an "activated" state. These cells were still Thy1-, and were thus different from fully activated LAK effectors which were Thy1+ cells, indicating that the full differentiation of LAK cells in vivo was arrested in the tumor-bearing hosts. We also found that the presence of small amounts of X-irradiated tumor cells prevented the generation of AK cells. These findings suggest that, in the tumor-bearing hosts, the presence of tumor cells triggers the activation of AK precursors; however, the same tumor cells may also be immunosuppressive, which prevents the full differentiation of AK precursors into AK effectors.

Animals↗
PubMed1991

Correlation between low-temperature immunosuppression and the absence of unsaturated fatty acid synthesis in murine T cells.

1. Studies were performed to determine if the inability of murine T cells to provide primary helper function at low temperature (27 degrees C) could be correlated with their inability to synthesize unsaturated fatty acids (UFAs). 2. In the absence of exogenous oleic acid (18:1), splenocytes responded to a T-dependent (TD) Ag (trinitrophenyl-keyhole limpet hemocyanin, TNP-KLH) at 37 degrees C but not at 27 degrees C. The addition of 150 microM 18:1 almost completely restored plaque-forming cell (PFC) responses to TNP-KLH at 27 degrees C but markedly suppressed PFC responses to the TD Ag at 37 degrees C. 3. During incubation at 27 degrees C, B cells converted 3- to 5-fold more stearic acid (18:0) to 18:1 and showed a greater accumulation of monounsaturated phospholipid molecular species than did T cells. 4. Following incubation in the presence of a rescuing dose of 18:1 (150 microM), both B and T cells accumulated large amounts of dioleoyl PC. 5. It is proposed that the absence of 18:1 synthesis in T cells is responsible for the unique low temperature susceptibility of this lymphocyte population.

Animals↗
PubMed1997

Evolutionary Relationship between Diapause and Cold Hardiness in the House Spider, Achaearanea tepidariorum (Araneae: Theridiidae).

The relationship between diapause and cold hardiness of the house spider, Achaearanea tepidariorum, differed geographically. In a cool-temperate population, enhanced chilling tolerance and supercooling ability were observed in diapause individuals, whereas a subtropical population showed only chilling tolerance. Because this spider is considered to be of tropical origin, it would follow that the ancestral diapause of this spider was equipped with chilling tolerance, but not with an increased supercooling ability. It seems that the ability to lower the supercooling point evolved through natural selection in the course of expansion of this species to the northern climates. Copyright 1997 Elsevier Science Ltd. All rights reserved

Journal Article↗
PubMed1997

Inflammatory processes may predispose children to high-altitude pulmonary edema.

We investigated retrospectively whether the preexistence of inflammation-producing illnesses such as viral respiratory tract infections contributed to the development of high-attitude pulmonary edema in children. We found that the large majority of native low-attitude children, but not adults, who had this form of edema after traveling to high altitude also had evidence of a preexisting illness. We speculate that the release of inflammatory mediators associated with these illnesses may be tolerated at sea level but may predispose children to increased capillary permeability when superimposed on hypoxia and, possibly, cold and exercise.

Adolescent↗
PubMed2004

Interactions among factors regulating phenological development and acclimation rate determine low-temperature tolerance in wheat.

BACKGROUND AND AIMS: Exposure to low temperatures (LT) produces innumerable changes in morphological, biochemical and physiological characteristics of plants, with the result that it has been difficult to separate cause and effect adjustments to LT. Phenotypic studies have shown that the LT-induced protective mechanisms in cereals are developmentally regulated and involve an acclimation process that can be stopped, reversed and restarted. The present study was initiated to separate the developmental factors determining duration from those responsible for rate of acclimation, to provide the opportunity for a more in depth analysis of the critical mechanisms that regulate LT tolerance in wheat (Triticum aestivum). METHODS: The non-hardy spring wheat cultivar 'Manitou' and the very cold-hardy winter wheat cultivar 'Norstar' were used to produce reciprocal near-isogenic lines (NILs) in which the vrn-A1 (winter) alleles of 'Norstar' were inserted into the non-hardy 'Manitou' genetic background and the Vrn-A1 (spring) alleles of 'Manitou' were inserted in the hardy 'Norstar' genetic background so that the effects of duration and rate of LT acclimation could be quantified. KEY RESULTS: Comparison of the acclimation curves of the NILs and their parents grown at 2, 6 and 10 degrees C established that the full expression of LT-induced genetic systems was revealed only under genotypically dependent optimum combinations of time and temperature. Both duration and rate of acclimation were found to contribute significantly to the 13.8 degrees C difference in lowest survival temperature between 'Norstar' and 'Manitou'. CONCLUSIONS: Duration of LT acclimation was dependent upon the rate of phenological development, which, in turn, was determined by acclimation temperatures and vernalization requirements. Rate of acclimation was faster for genotypes with the 'Norstar' genetic background but the ability to sustain a high rate of acclimation was dependent upon the length of the vegetative stage. Complex time/temperature relationships and unexplained genetic interactions indicated that detailed functional genomic or phenomic analyses of natural allelic variation will be required to identify the critical genetic components of a highly integrated system, which is regulated by environmentally responsive, complex pathways.

Acclimatization↗
PubMed2003

Disruption mutations of ADA2b and GCN5 transcriptional adaptor genes dramatically affect Arabidopsis growth, development, and gene expression.

We previously identified Arabidopsis genes homologous with the yeast ADA2 and GCN5 genes that encode components of the ADA and SAGA histone acetyltransferase complexes. In this report, we explore the biological roles of the Arabidopsis ADA2b and GCN5 genes. T-DNA insertion mutations in ADA2b and GCN5 were found to have pleiotropic effects on plant growth and development, including dwarf size, aberrant root development, and short petals and stamens in flowers. Approximately 5% of the 8200 genes assayed by DNA microarray analysis showed changes of expression in the mutants, three-fourths of which were upregulated and only half of which were altered similarly in the two mutant strains. In cold acclimation experiments, C-repeat binding factors (CBFs) were induced in the mutants as in wild-type plants, but subsequent transcription of cold-regulated (COR) genes was reduced in both mutants. Remarkably, nonacclimated ada2b-1 (but not gcn5-1) mutant plants were more freezing tolerant than nonacclimated wild-type plants, suggesting that ADA2b may directly or indirectly repress a freezing tolerance mechanism that does not require the expression of CBF or COR genes. We conclude that the Arabidopsis ADA2b and GCN5 proteins have both similar and distinct functions in plant growth, development, and gene expression and may be components of both a common coactivator complex and separate complexes with distinct biological activities.

Adaptation, Physiological↗
PubMed2002

Pathophysiology and assessment of neuropathic pain in Fabry disease.

UNLABELLED: Severe neuropathic pain and hypohidrosis are important symptoms of Fabry disease, particularly in the first three decades of life. The pain is associated with a length-dependent small-fibre neuropathy that also causes a selective deficiency of cold perception. Cold exposure often accentuates the pain and worsens thermal perception. The hypohidrosis leads to poor exercise and heat tolerance. The mechanisms by which alpha-galactosidase A deficiency causes these physiological abnormalities are poorly understood. The stored glycolipid (globotriaosylceramide) may interfere with the function of cellular membrane proteins, such as ion channels, or may lead to cytotoxicity. The characteristic neuropathic pain can be symptomatically treated with various types of anticonvulsant drugs, such as carbamazepine. Improvement in neuropathic pain as a primary outcome measure has been useful in demonstrating that enzyme replacement therapy is effective in improving pain-related quality of life in Fabry disease. CONCLUSIONS: The dysfunction of the peripheral nervous system is easily assessable and more readily reversible with specific therapy than the destructive processes that occur in organs such as the kidney. In future, therefore, it is likely that neuropathic pain, quantitative sensory testing and hypohidrosis will serve as clinical outcome measures for studies of specific and effective therapies for Fabry disease.

Fabry Disease↗