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PubMed2000

Occupational injuries in the mining industry and their association with statewide cold ambient temperatures in the USA.

BACKGROUND: Relatively few occupational epidemiological studies have been conducted concerning the association between cold ambient temperatures and cold exposure injuries, and fewer still of traumatic occupational injuries and cold ambient temperatures. METHODS: The association of ambient temperature and wind data from the National Climatic Data Center with injury data from mines reported to the Mine Safety and Health Administration (MSHA) was evaluated over a 6 year period from 1985-1990; 72,716 injuries from the seven states with the most numerous injuries were included. Temperature and wind data from each state's metropolitan weather stations were averaged for each day of the 6 year period. A weighted linear regression tested the relationship of ungrouped daily temperature and injury rate for all injury classes. For cold exposure injuries and fall injuries, relative incidence rates for grouped temperature data were fit with Poisson regression. RESULTS: As temperatures decreased, injury rates increased for both cold exposure injuries and slip and fall injuries. The association of slip and fall injuries with temperature was inverse but not strictly linear. The strongest association appeared with temperatures 29 degrees F and below. The injury rates for other accident categories increased with increasing ambient temperatures. CONCLUSIONS: This study suggests that statewide average ambient temperature reflects the expected association between the thermal environment and cold exposure injuries for workers, but more importantly, documents an association between ambient temperatures and occupational slip and fall injuries.

Accidental Falls↗
PubMed1991

Effects of temperature on the performance of finishing swine: II. Effects of a cold, diurnal temperature on average daily gain, feed intake, and feed efficiency.

Forty-eight crossbred barrows and gilts weighing 84.5 +/- .33 kg were used during two 21-d trials to investigate the effects of a cold, diurnal temperature (CD; -5.0 to 8.0 degrees C) compared with a constant, thermoneutral temperature (TN; 20 degrees C) and the effects of sex (barrows vs gilts) on performance. A second objective was to determine shrinkage as a result of a 24-h fast immediately after the 21-d study of hogs commingled vs those not commingled for both environmental treatments (CD vs TN). Pigs housed in the CD chamber gained 27.2% more slowly (P less than .001; 75 vs 1.03 kg/d) than those in the TN environment and consumed 5.7% more feed (P less than .05; 3.88 vs 3.67 kg/d). The lower ADG and higher feed intake (FI) exhibited by the CD pigs resulted in poorer (P less than .05) feed efficiency (F/G; 5.33 vs 3.73, respectively). A temperature x sex interaction occurred for ADG but not for FI or F/G. Twenty-four-hour shrink for the CD pigs was 16.4% less than for the TN pigs (3.72 vs 4.45%, respectively); however, commingling did not affect shrinkage.

Animals↗
PubMed1992

The appearance of Fos protein-like immunoreactivity in the hypothalamus of developing rats in response to cold ambient temperatures.

This study examined cellular activity in the hypothalamus of developing rats in response to cold environmental temperatures. The appearance of the nuclear protein, Fos, in response to cold ambient temperatures in rats three to 35 days of age was used as a marker of neuronal activation. Fos-positive nuclei were first seen in response to cold ambient temperatures in the ventromedial nucleus at three days of age, the paraventricular nucleus at eight days of age, the preoptic-anterior hypothalamus at 10 days of age and the anterior hypothalamic nucleus at 21 days of age. The rectal temperature of the 10-day-old pups dropped by less than half that measured in the nine-day-old pups after 1 h in the cold. It is possible that the activation of neurons in the preoptic-anterior hypothalamus in the 10-day-old animal may contribute to the decreased hypothermia observed in the 10-day-old after 1 h in the cold. The high density of Fos-like immunoreactive-labeled nuclei in the preoptic-anterior hypothalamus in the 10-day-old rats that were exposed to the cold environment indicates increased neuronal activity at this site. The results suggest that, at least in the preoptic-anterior hypothalamus, the appearance of the cellular response to cold ambient temperatures is coincidental with a thermogenic response.

Acclimatization↗
PubMed1975

Depression of sublingual temperature by cold saliva.

Sublingual and oesophageal temperatures were compared at various air temperatures in 16 subjects. In warm air (25-44 degrees C) sublingual temperatures stabilized within plus or minus 0-45 degrees C of oesophageal temperatures, but in air at room temperature (18-24 degrees C) they were sometimes as much as 1-1 degrees C below and in cold air (5-10 degrees C) as much as 4-4 degrees C below oesophageal readings. The sublingual-oesophageal temperature difference in cold air was greatly reduced by keeping the face warm, but it was not reduced in two patients breathing through tracheostomies and thereby eliminating cold air flow from the nose and pharynx. Parotid saliva temperature was low and saliva flow high during exposure, and cold saliva seemed to be mainly responsible for the erratic depression of sublingual temperature in the cold. These results indicate hazards in the casual use of sublingual temperatures, and indicate that external heat may have to be supplied to enable them to give reliable clinical assessments of body temperature.

Adolescent↗
PubMed2003

Involvement of the parabrachial nucleus in thermogenesis induced by environmental cooling in the rat.

The parabrachial nucleus (PBN), an integration site for autonomic regulation in the mesopontine brainstem, receives sensory information about cold temperatures from the skin. Here we investigated the role of the PBN in thermoregulation. Unilateral stimulation of the PBN (10-40 microA, 5 min) immediately increased the rate of O(2) consumption ( VO(2)) and heart rate, and the magnitude of these responses increased with the intensity of the stimulus in urethane-anesthetized rats. High-intensity (40 microA) stimulation of the PBN increased the temperature of the interscapular brown adipose tissue and that of the colon but had no effect on that of the tail skin, although weaker stimulation was without effect on these temperatures. Next, we examined the effects of bilateral lesioning of the PBN on environmental cooling-induced thermogenesis in conscious rats. Exposure of PBN-lesioned rats to a cool (16.6 degrees C) environment induced a significantly smaller increase in VO(2) than did that of rats with a sham operation or with lesions made outside of the PBN, and resulted in a marked decrease in body temperature in PBN-lesioned rats but not in other rats. Both frequency and duration of gross motor activity in the cool environment were similar between PBN-lesioned and sham-operated rats. These results suggest that the PBN is involved in the central mechanisms of cooling-induced thermogenesis.

Anesthesia↗
PubMed1991

Nasal mucosal hypersensitivity in guinea pigs intermittently exposed to cold.

To develop an animal model for experimental nasal hypersensitivity and hyperreactivity, guinea pigs were subjected to intermittent exposure to cold temperature (intermittent cold stress, SART stress) for 5 consecutive days. In SART-stressed guinea pigs, nasal mucosal hypersensitivity to histamine evoking sneeze response and nasal hypersecretion in response to methacholine were observed. The hypersensitivity remained for further 7 days after being released from SART stress. On the other hand, such nasal mucosal hypersensitivity was not caused by a continuous cold stress alone, suggesting that intermittent exposure to cold may be of importance for the appearance of nasal mucosal hypersensitivity. In passively sensitized SART-stressed guinea pigs, the quantity of nasal secretion induced by an allergen was significantly increased compared with that of a group of normal animals. The expression of muscarinic acetylcholine receptor (m-ACh.R) became higher in SART-stressed guinea pigs. Thus, hypersensitivity and hyperreactivity in this system were found to be associated with an increase in density of m-ACh.R. SART-stressed guinea pigs will serve as an animal model for hypersensitivity in nasal mucosa, which would be useful for the study of nasal allergy.

Animals↗
PubMed2005

The effect of stabilizers and denaturants on the cold denaturation temperatures of proteins and implications for freeze-drying.

PURPOSE: The aim of the study is to investigate the effects of stabilizers and denaturants on the thermal and cold denaturation temperatures of selected proteins in systems of interest to freeze-drying. METHODS: Beta-lactoglobulin and phosphoglycerate kinase (PGK) were chosen as model proteins. Protein thermal and cold denaturation temperatures were determined by both conventional and modulated differential scanning calorimetry and verified by tryptophan emission spectroscopy in selected systems. RESULTS: The cold denaturation of beta-lactoglobulin was reversible, whereas the thermal denaturation was only reversible at high scanning rate (10 degrees C/min). The cold denaturation temperatures of beta-lactoglobulin decreased with an increase in protein concentration (self-stabilization). The cold denaturation temperature increased with increases in pH (from pH 2 to 7) with about 4.6 degrees C increase per unit pH change. All stabilizers studied (i.e., sucrose, trehalose and glycerol) increased the thermal denaturation temperature of the proteins studied and decreased the cold denaturation temperature. The effect of sucrose in decreasing the PGK cold denaturation temperature [40 degrees C per molar concentration increase (40 degrees C/M)] was of the same magnitude as for beta-lactoglobulin (36 degrees C/M). The effect of stabilizers on cold denaturation temperatures is much greater than the effect on thermal denaturation temperatures. With sucrose, the beta-lactoglobulin thermal denaturation temperature increases only about 5 degrees C from 0 to 2.7 M, whereas the decrease in cold denaturation temperature was more than 35 degrees C even at sucrose concentrations as low as 0.9 M. Denaturants (urea and guanidine hydrochloride) increased the cold denaturation temperatures of proteins and thereby destabilized protein; the magnitudes were 9 degrees C/M (urea on Tcd of beta-lactoglobulin) and 65 degrees C/M (guanidine hydrochloride on PGK) compared with literature data of 16 degrees C/M (guanidine hydrochloride on beta-lactoglobulin). The cold denaturation temperatures of beta-lactoglobulin and PGK extrapolated to zero concentration of denaturants were -14 and -26 degrees C, respectively. CONCLUSIONS: The protein cold denaturation temperature was pH-, protein concentration-, and additive-dependent. Stabilizers, such as sugars and/or polyols, can stabilize both protein thermal and cold denaturation, whereas the denaturants destabilize protein cold denaturation. The stabilization effect on protein cold denaturation is much larger than on thermal denaturation, a result of great importance in protein freeze-drying.

Calorimetry, Differential Scanning↗
PubMed2005

Rats desensitized by capsaicin alter their food intake regulation especially at cold ambient temperature.

Adult rats were treated subcutaneously for 10 days with capsaicin, and their food intake and body weight were recorded for almost 6 weeks after stopping the treatment. The animals were exposed to different ambient temperatures: Ta (22, 32, 35, 10 and 22 degrees C). In the capsaicin-treated group a persistent increase in food intake and a reduction of body weight were observed when the animals were exposed to the lowest Ta of 10 degrees C. Starting from this temperature, food intake remained significantly higher than in controls until the end of the experiment at a Ta of 22 degrees C. The discrepancy between body weight increase and food intake especially at low temperature (10 degrees C) suggests that capsaicin could prevent suppression of food intake through the mediation of capsaicin-sensitive vagal afferent fibers by activation of cold-temperature-sensitive receptors.

Animals↗
PubMed2006

The chloroplast lumen and stromal proteomes of Arabidopsis thaliana show differential sensitivity to short- and long-term exposure to low temperature.

Cold acclimation and over-wintering by herbaceous plants are energetically expensive and are dependent on functional plastid metabolism. To understand how the stroma and the lumen proteomes adapt to low temperatures, we have taken a proteomic approach (difference gel electrophoresis) to identify proteins that changed in abundance in Arabidopsis chloroplasts during cold shock (1 day), and short- (10 days) and long-term (40 days) acclimation to 5 degrees C. We show that cold shock (1 day) results in minimal change in the plastid proteomes, while short-term (10 days) acclimation results in major changes in the stromal but few changes in the lumen proteome. Long-term acclimation (40 days) results in modulation of the proteomes of both compartments, with new proteins appearing in the lumen and further modulations in protein abundance occurring in the stroma. We identify 43 differentially displayed proteins that participate in photosynthesis, other plastid metabolic functions, hormone biosynthesis and stress sensing and signal transduction. These findings not only provide new insights into the cold response and acclimation of Arabidopsis, but also demonstrate the importance of studying changes in protein abundance within the relevant cellular compartment.

Acclimatization↗
PubMed2006

Activation of zoosporogenesis-specific genes in Phytophthora infestans involves a 7-nucleotide promoter motif and cold-induced membrane rigidity.

Infections of plants by the oomycete Phytophthora infestans typically result from zoospores, which develop from sporangia at cold temperatures. To help understand the relevant cold-induced signaling pathway, factors regulating the transcription of the zoosporogenesis-specific NIF (nuclear LIM-interactor-interacting factor) gene family were examined. Sequences required for inducing PinifC3 were identified by analyzing truncated and mutated promoters using the beta-glucuronidase reporter in stable transformants. A 7-nucleotide (nt) sequence located 139 bases upstream of the major transcription start point (GGACGAG) proved essential for the induction of PinifC3 when sporangia were shifted from ambient to cold temperatures. The motif, named the cold box, also conferred cold inducibility to a promoter normally activated only during sexual development. An identical motif was detected in the two other zoosporogenesis-specific NIF genes from P. infestans and three Phytophthora sojae orthologues, and a closely related sequence was found in Phytophthora ramorum orthologues. The 7-nt motif was also found in the promoters of other zoosporogenesis-induced genes. The presence of a cold box-interacting protein in nuclear extracts of P. infestans sporangia was demonstrated using electrophoretic mobility shift assays. Furthermore, zoospore release and cold box-regulated transcription were stimulated by the membrane rigidizer dimethyl sulfoxide and inhibited by the membrane fluidizer benzyl alcohol. The data therefore delineate a pathway in which sporangia perceive cold temperatures through membrane rigidity, which activates signals that drive both zoosporogenesis and cold-box-mediated transcription.

Amino Acid Motifs↗
PubMed1998

The physical and psychological experience of pain: the effects of labeling and cold pressor temperature on three pain measures in college women.

Using the cold pressor test, three experiments were conducted to investigate the effects of water temperature and labeling on three dependent measures in college women: behavioral pain tolerance (BPT), a sensory rating of the pain experience (SR) and a parallel affective rating of the experience (AR). Temperature of the cold pressor was varied as the physical factor; labels (discomfort, pain, vasoconstriction pain) were varied as the psychological factor. Experiment I varied only water temperature; colder temperatures led to significantly lower BPT scores and significantly higher SR and AR scores. Experiment 2 varied only labeling and demonstrated that BPT decreased and AR increased as labels became more painful-sounding; in contrast, SR was unaffected by labeling. In Experiment 3 both the psychological and physical factors were varied simultaneously. Results indicated significantly higher BPT scores as the water temperature increased and the pain label became more benign. In addition, both SR and AR were sensitive to changes in temperature, whereas only AR was affected by changes in labeling.

Adult↗
PubMed1993

Effects of acute exposure to cold on pulmonary arterial blood pressure in awake rats.

This study examined alterations in the degree of exposure to cold and the pulmonary arterial pressure in awake, catheter-implanted rats. Seven male Wistar rats weighing 280 to 300 g were used. Two special hand-made catheters were inserted into the pulmonary artery and the level of the aortic arch, respectively. Each animal was exposed once to each of four cold temperatures, i.e. 5, 0, -5 and -10 degrees C, and 25 degrees C temperature. Acute cold exposures produced significant increases in pulmonary arterial pressure (p < 0.05). Pulmonary arterial pressure and the ratio of pulmonary arterial pressure to systemic arterial pressure increased gradually with exposure to decreasing temperatures (p < 0.05). These results indicate the possible significance of greater cold exposure in the increased occurrence of high altitude sickness, such as high altitude pulmonary edema. Further work is necessary to investigate the direct relation between cold-induced pulmonary arterial pressure increments and high altitude pulmonary edema.

Animals↗