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At least 19 recordsLinked to original sources
PubMed2002

Impact of hot temperatures on death in London: a time series approach.

STUDY OBJECTIVE: This study investigated the relation between heat and mortality in London to determine the temperature threshold at which death rates increase and to quantify the effect of extreme temperatures on mortality. DESIGN: Daily data on all cause mortality and temperature were obtained for a 21 year period and the relation between them investigated both graphically and by using non-parametric time series methods of analysis. SETTING: Greater London. PARTICIPANTS: Daily mortality counts in Greater London between January 1976 and December 1996. MAIN RESULTS: A plot of the basic mortality-temperature relation suggested that a rise in heat related deaths began at about 19 degrees C. Average temperatures above the 97th centile value of 21.5 degrees C (excluding those days from a 15 day "heatwave" period in 1976) resulted in an increase in deaths of 3.34% (95% CI 2.47% to 4.23%) for every one degree increase in average temperature above this value. It was found that the 1976 heatwave resulted in a particularly large number of deaths in comparison with other hot periods. CONCLUSIONS: These results suggest that heat related deaths in London may begin at relatively low temperatures. Hot days occurring in the early part of any year may have a larger effect than those occurring later on; and analysis of separate heatwave periods suggest that episodes of long duration and of highest temperature have the largest mortality effect.

Air Pollution↗
PubMed1997

Cyclo (His-Pro) modulation of body temperature at hot ambient temperature in the desert rat (Mastomys natalensis).

Cyclo(His-Pro) (CHP) has been shown to facilitate cold-induced hypothermia in the desert rat Mastomys natalensis. In the present study, we examined the role of endogenous CHP in hyperthermia induced by hot ambient temperature (40 degrees C) in the above rodent species. The results of these studies show that housing rodents at 40 degrees C resulted in a altered distribution of CHP in the brain, with a rise in hypothalamic content accompanied by an increase in rectal temperature. While administration of exogenous CHP decreased hyperthermia, immunoneutralization of endogenous CHP increased hyperthermia. The results of these studies show that changes in endogenous CHP levels may affect body temperature regulation.

Animals↗
PubMed1990

Effects of feeding lasalocid on performance of broilers in moderate and hot temperature regimens.

Three trials were conducted in environmental chambers to study the effects of feeding lasalocid on broiler performance. Birds were randomly assigned at 31 or 35 days of age to one of four treatment groups: hot cyclic (26.7 to 37.8 C and 90 to 40% RH) with basal diet; hot cyclic with lasalocid diet (88 mg/kg); moderate constant (21 C and 50% RH) with basal diet; or moderate constant with lasalocid diet. All birds were killed and processed 2 wk after the start of each trial. Percentage of carcass yield and fat pad weight were determined. In the moderate temperature regimen, lasalocid feeding caused a depression in the 2nd wk gain (469 versus 486 g) but not in the final 2-wk gain. In the hot temperature regimen, birds fed lasalocid gained significantly more weight in the 2nd wk than those fed the basal diet (341 g versus 325 g) and had a significantly better feed conversion in the 2nd wk (2.04 versus 2.61) and overall (2.07 versus 2.32) than those fed the basal diet.

Animals↗
PubMed2005

High kidney stone risk in men working in steel industry at hot temperatures.

OBJECTIVES: To study the incidence of urinary lithiasis and metabolic alterations among male employees from a steel industry who were exposed to high temperatures in the work environment. METHODS: A retrospective cross-sectional study was performed and consisted of two stages. First, the incidence of urolithiasis among the industry's 10,326 employees was assessed. These employees were divided into two group's: group 1 (n = 1289) consisted of the hot-area workers (temperature greater than 45 degrees C) and group 2 (n = 9037) consisted of those working in areas at room temperature. In the second stage, 59 workers without urolithiasis who underwent a metabolic evaluation were divided into two group's: group 3 (n = 34) consisted of hot-area workers and group 4 (n = 25) consisted of those working in areas at room temperature. Evaluations were made of calcium, creatinine, and uric acid in serum; in the 24-hour urine samples, we assessed the volume, calcium, uric acid, citrate, and oxalate. RESULTS: Of the 10,326 workers, 181 (1.75%) had presented with at least one episode of urinary stones. Of these, 103 were among the hot-area workers (8.0%) and 78 among the room-temperature workers (0.9%; P <0.001). The metabolic evaluation showed that the hot-area group (group 3), compared with the room-temperature group (group 4), presented more frequently with hypocitraturia (55.8% versus 28%, P = 0.03) and low urinary volume (79.4% versus 48%, P = 0.01). CONCLUSIONS: Workers exposed to high temperatures presented with a ninefold risk of lithiasis. Hypocitraturia and low urine volumes were the metabolic alterations observed.

Adult↗
PubMed1997

Effects of ruminally inert fat and evaporative cooling on dairy cows in hot environmental temperatures.

Under hot summer conditions of Tucson, Arizona, 24 Holstein cows (mean = 80 d of lactation) were assigned for 56 d to four treatments in a randomized block design with a 2 x 2 factorial arrangement of treatments. Factors were 1) medium [4.6% of dry matter (DM)] versus high (7.4% of DM) amounts of dietary fat and 2) corral shade only versus shade equipped with evaporative cooling. The high fat diet contained 3% prilled fatty acids. The efficiency of the conversion of feed to milk tended to be better for cows fed prilled fat than for cows fed medium dietary fat, but other lactation measurements were unaffected. Cows with access to evaporative cooling had greater milk yields than did cows with access to shade only. Prilled fatty acids did not depress the percentage of milk protein, but reduced short- and medium-chain fatty acids (C6:0 to C14:0) in milk fat and increased palmitic acid. Digestibilities of DM, organic matter, crude protein, acid detergent fiber, neutral detergent fiber, and starch were unaffected by amount of fat or by cooling method, but prilled fatty acids tended to decrease apparent digestibility of fatty acids. No differences were observed among treatments in respiration rates or rectal temperatures. When rectal temperatures were determined, cows were crowded, which probably negated detection of an effect of evaporative cooling. Evaporative cooling increased milk yield of cows in hot weather, but the addition of 3% fatty acids did not increase yield, and no interactions were observed.

Animals↗
PubMed2005

Long oligonucleotide microarrays in wheat: evaluation of hybridization signal amplification and an oligonucleotide-design computer script.

A computer script was written in the Perl language to design equal-length long oligonucleotides from DNA sequences. The script allows the user to specify G + C content, melting temperature, self-complementarity, the maximum number of contiguous duplicate bases, whether to start with the first start codon and whether to report reverse complements. Microarrays were fabricated with 95 oligonucleotides (60 mers) representing 41 genes. The microarray was interrogated with cDNA from roots and shoots of two near-isogenic lines and a commercial cultivar of Triticum aestivum L. (hexaploid wheat) challenged with cold temperature, hot temperature, or the biological control bacterium Pseudomonas fluorescens. Self-complementarity of the oligonucleotides was negatively correlated with signal intensity in 23 of 54 arrays (39%; P <0.01). Tyramide signal amplification was essential for signal generation and detection. Genes involved in signal transduction pathways responded similarly following exposure to cold, heat and P. fluorescens, suggesting intersection of the pathways involved in response to these disparate stress factors. Microarray results were corroborated by quantitative real-time PCR in 75% of samples assayed. We conclude that long oligonucleotide microarrays for interrogation with cDNA from hexaploid wheat should be constructed from oligonucleotides having minimal self complementarity that also meet user-specified requirements of length, G + C content and melting temperature; multiple oligonucleotides should be used to represent each gene; and Tyramide signal amplification is useful in wheat oligonucleotide microarray studies.

Base Sequence↗
PubMed1991

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

Ninety-six crossbred barrows and gilts weighing 90 +/- .67 kg were used during a 21-d study to determine the effects of a hot, diurnal temperature (H; 22.5 to 35 degrees C) compared with a constant, thermoneutral temperature (TN; 20 degrees C) and the effects of sex (barrows vs gilts) on performance. A secondary objective included the determination of weight loss as a result of a 24-h fast immediately after the 21-d feeding study of commingled vs not commingled hogs of both environmental treatments (TN and H). Pigs housed in the hot, diurnal temperature gained 16.3% more slowly (P less than .001;.77 vs. .92 kg/d) than those in the constant, thermoneutral environment. Feed intake (FI) for the H pigs was 10.9% less (P less than .001; 3.01 vs 3.38 kg/d) than that for the TN pigs. The H pigs gained 17.6 g/d less and consumed 43.5 g/d less feed for every C degrees above 20 degrees C; however, no differences were observed for feed efficiency (F/G; 3.86 vs 4.19 kg for the TN and H pigs, respectively). Average daily gain and feed/gain (F/G) were not affected by sex. Likewise, no significant interactions of temperature x sex were observed for ADG, FI, or F/G. Weight loss (shrinkage) during the 24-h fast was not affected by commingling; however, the H pigs lost 17.5% more weight (P less than .05) than the TN pigs (3.82 vs 3.25%, respectively).

Animals↗
PubMed1988

Modification of the antinociceptive effect of morphine by acute and chronic administration of clomipramine in mice.

The antinociception effect of clomipramine and the combination of clomipramine and morphine was evaluated using the constant temperature hot plate test, the increasing temperature hot plate test and the formalin test in mice. Both a single dose of clomipramine (10 mg/kg) given intraperitoneally (i.p.) and chronic clomipramine treatment (10 mg/kg/day, i.p., for 7 days) induced antinociception. When morphine (5 mg/kg), given subcutaneously (s.c.), and clomipramine were combined, an increased antinociceptive effect compared to morphine alone was observed in all tests. In the increased temperature hot plate test and in the formalin test increased antinociception was also observed when morphine was combined with chronic clomipramine treatment. In the constant temperature hot plate test no additional effect compared to morphine alone was observed when morphine and chronic clomipramine treatment were combined. These results indicate that clomipramine has an antinociceptive effect in itself, and that it may enhance the antinociceptive effects of morphine. The differences between the tests indicate that different nociceptive mechanisms are involved, and that the combination of clomipramine and morphine may be beneficial for some types of nociceptive stimuli, but not for others.

Animals↗
PubMed1990

Hot water temperature in Dunedin homes with preschool children.

The mean temperature of the hot water supply of 62 randomly selected Dunedin homes with preschool children was 67.8 degrees C. More than 95% of the households visited had temperatures above the recommended temperature of 55 degrees C. The temperature was related to the socioeconomic status of the major earner of the household, the thermostat setting, the age of the water cylinder and its size. Accessible thermostats were of the water cylinder and its size. Accessible thermostats were only reliable in cylinders under 20 years old.

Burns↗
PubMed1991

The increasing-temperature hot-plate test: an improved test of nociception in mice and rats.

The increasing-temperature hot-plate test has several advantages compared to the conventional hot-plate test, but available equipment has been impractical and restricted with regard to stimulus control. We now describe an apparatus consisting of an aluminum plate that is heated and cooled by Peltier elements in contact with its lower surface. Several plates can be used simultaneously, individually controlled by electronic proportional feedback circuits. The set temperature of the feedback circuit is controlled by a computer program run on an IBM XT-compatible PC, so that a linear increase in temperature is achieved. Experiments were performed using rats and mice, with hindpaw licking as an end-point criterion. Experiments with various heating rates showed that 3.0 degrees C/min is the lowest rate that can be applied without signs of stress in the animals. On the basis of the recorded data, nociceptive temperature thresholds were calculated to be approximately 44.5 degrees C for both rats and mice. Inspection of the paws after analgesic treatment and exposure to different end-point temperatures suggested that a cutoff temperature of 50 degrees C should be employed to minimize tissue damage. Testing at ambient temperatures of 18 degrees and 28 degrees C yielded similar results for rats, whereas mice responded at significantly higher plate temperatures in the colder environment. Dose-related antinociceptive effects were demonstrated for morphine and paracetamol in both species. The results confirm that the increasing-temperature hot-plate test is a valuable test of nociception, which is also suitable for demonstrating the antinociceptive effects of nonopioid analgesics. The test may also be used to estimate the nociceptive temperature threshold.

Acetaminophen↗
PubMed1978

[Influence of a hot environmental temperature on the evolution of experimental paludism of the mouse with Plasmodium berghei berghei].

Swiss Mice infected with Plasmodium berghei berghei and maintained in permanence in a hot environmental temperature undergo a chronic infection whereas controls maintained at the laboratory temperature develop always an acute and lethal infection. The hot environmental temperature does not seem to have any action on the pathogenicity of the parasites. Host defences are stimulated.

Animals↗