Effects of alternating exposure to cold and heat for 14 days on cold tolerance in winter

People are exposed to heat regularly due to their jobs or daily habits in cold winter, but few studies have reported whether parallel heat and cold exposure and diminish cold acclimation. This study was conducted to investigate the effects of alternating exposure to cold and heat on cold tolerance in eight young males. A daily acclimation program to cold and heat, which consisted of 2-h sitting at 10 °C air in the morning and 2-h running and rest at 30 °C air in the afternoon, was conducted for 14 consecutive days. Eight male subjects participated in a cold tolerance test (10 °C [ ± 0.3], 40%RH[ ± 3]) before (PRE) and after (POST) completing the alternating exposure program. During the cold tolerance test, subjects remained sitting upright on a chair for 60 min. Rectal temperature (T_re) was lower in POST than in PRE during the 60-min cold tolerance test (P = 0.027). During the cold tolerance test, systolic, diastolic, and mean arterial blood pressures in POST were lower than those in PRE (P = 0.006, P = 0.005, and P = 0.004). No significant differences in skin temperatures between PRE and POST were found for the cold tolerance test. There were no significant differences in energy expenditure during cold exposure between PRE and POST. Subjects felt less cold in POST than in PRE (P = 0.013) whereas there was no significant difference in overall thermal comfort between PRE and POST. These results suggest that cold adaptation can still occur in the presence of heat stress.     

Effects of acute exercise on serum interleukin-17 concentrations in hot and neutral environments in trained males

The purpose of this study was to determine the effects of acute exercise on IL-17 concentrations in hot and neutral environments in trained males. Ten trained, non-heat acclimated males performed two 1 h run on treadmill at 60% VO2max in neutral (22±1 °C, 50±5RH) and hot (35±1 °C, 50±5) temperature conditions. Samples of the venous blood were taken (Pre, post, 2 h post) for determination of serum IL-17, cortisol concentrations and numbers of leukocytes and neutrophils. In addition, body temperature, RPE and PVC during exercise were measured. The collected data were analyzed using the Repeated-Measures analyses of variance and Bonferroni post hoc and Paird T tests (p<0.05). The concentration of cortisol and total number of leukocytes increased significantly after exercise, in both conditions (p<0.0001) and were significantly higher in hot than neutral (p=0.016, p=0.002). During the rest period (2 h post) the number of neutrophils increased significantly in hot environment (p=0.018). The concentrations of IL-17 increased significantly only after exercise in hot (p<0.0001) and were significantly higher during hot than neutral (p=0.002). The results suggest that exercise in hot environment cause increase in body temperature, perceived exertion and cardiac-vascular changes which are sufficient to elicit immune, hormonal and inflammatory responses. The present results confirm the additive effect of heat stress on the IL-17 response during exercise.     

The effect of thermopreference on circadian thermoregulation in sprague-dawley and fisher 344 rats

Interstrain differences in thermoregulation of rats are important in biomedical research because subtleties in thermoregulatory sensitivities may greatly affect data collected. Little is known regarding how individual rodent strains differentially utilize behavioral thermal preference to regulate core temperature (Tc). Sprague-Dawley (SD) and Fischer 344 (F344) rats are known to have differences in thermoregulation including heat tolerance and are useful models to study interstrain differences in thermoregulation. Adult male SD and F344 rats of similar body size were implanted with radiotelemetry thermoprobes (DSI) to measure Tc and MA and housed in either a longitudinal temperature gradient with an ambient temperature (Ta) range of ∼15–40 °C to measure selected Ta (STa) or control environment maintained at a Ta of 23 °C. When continuously monitored for 48 h, Tc and MA increased at night, while STa decreased, according to their normal circadian cycle in both strains. SD rats were more active than F344 rats throughout the circadian cycle (SD gradient: day=12.9±1.2 m/h, night=32.1±2.4 m/h; F344 gradient: day=4.1±0.6 m/h, night=16.8±1.8 m/h; p<0.05 interstrain and circadian effects). The STa of each strain was greater during the daytime (SD: 26.4±0.2 °C; F344: 27.8±0.3 °C) than at night (SD: 24.7±0.3 °C; F344: 25.7±0.3 °C) confirming past studies that thermopreference during the day and night is greater than standard room temperature (∼23 °C). Correlations between MA and Tc suggest that MA has a greater effect on Tc in the F344 but not the SD strain when housed in a temperature gradient. There were significant strain differences in Tc depending on whether rats were housed in a temperature gradient. That is, the control F344 rats had a lower Tc during the transition from dark to light compared to rats housed in a gradient. Tc of the SD strain was unaffected by housing in the gradient. Rats are typically housed at a standard room temperature of 23 °C. However, the results demonstrate that when given the opportunity to behaviorally thermoregulate in a temperature gradient, the F344 strain selects a warmer environment that affects the regulation of Tc. This may be important in the experimenters' choice of ambient temperatures to house and study rats and other rodents.     

Shivering modulation in humans: Effects of rapid changes in environmental temperature

During cold exposure, increase in heat production is produced via the activation of shivering thermogenesis and nonshivering thermogenesis, the former being the main contributor to compensatory heat production in non-acclimatized humans. In rats, it has been demonstrated that shivering thermogenesis is modulated solely by skin thermoreceptors but this modulation has yet to be investigated in humans. The aim of this study was to determine if cold-induced shivering in humans can be modulated by cutaneous thermoreceptors in conditions where increases in heat loss can be adequately compensated by increases in thermogenic rate. Using a liquid-conditioned suit, six non-acclimatized men were exposed to cold (6 °C) for four 30 min periods, each of them separated by 15 min of heat exposure (33 °C). Core temperature remained stable throughout exposures whereas skin temperatures significantly decreased by 12% in average during the sequential cold/heat exposures compared to baseline (p<0.0001). Shivering intensity and metabolic rate increased significantly during 6 °C exposures (3.3±0.7% MVC, 0.40±0.0 L O₂/min, respectively) and were significantly reduced during 33 °C exposure (0.5±0.1% MVC, 0.25±0.0 L O₂/min; p<0.005 for both). Most importantly, shivering could be quickly and strongly inhibited during 33 °C exposure although skin temperature often remained below baseline values. In conclusion, under compensatory conditions, cutaneous thermoreceptors appear to be a major modulator of the shivering response in humans and seem to react rapidly to changes in the microclimate right next to the skin and to skin temperature.     

The effect of heat acclimation on maximal urine osmolality in humans

The purpose of the current study was to determine the effect of 9 days of active heat acclimation on maximal urine osmolality (MUO) in humans. Eight subjects completed 9 days of heat acclimation, which consisted of a daily 90 min exercise session in a heated environmental chamber. Before and following heat acclimation the subjects abstained from drinking fluids for 15 h, and urine samples were collected to measure MUO. The subjects successfully heat acclimated as evidenced by a significant (P<0.05) decrease in the mean±SD exercise core temperature (37.7±0.3 °C on day 1 to 37.4±0.3 °C on day 9) and heart rate (143±17 bpm on day 1 to 128±14 bpm on day 9). The mean pre- and post-heat acclimation MUOs were 868±117 and 846±89 mmol kg⁻¹, respectively, which were not significantly different (P>0.05). Previous studies have shown that prolonged dehydration can increase the MUO in various mammalian species, including humans. In contrast, the results of the current study suggest that 9 days of active heat acclimation, without significant dehydration, does not affect the MUO in humans.     

Seasonal acclimatization to the hot summer over 60 days in the Republic of Korea suppresses sweating sensitivity during passive heating

The main objective of this study was to determine the central mechanisms involved in suppression of thermal sweating after seasonal acclimatization (SA) during passive heating (immersing the legs in 43 °C hot water for 30 min). Testing was performed in July (before-SA) and August (after-SA) [25.2±2.2 °C, 73.9±10.3% relative humidity (RH), Cheonan (Chungnam,126° 52′N, 33.38′E), in the Republic of Korea. All experiments were carried out in an automated climatic chamber (25.0±0.5 °C and RH 60.0±3.00%). Twelve healthy men (height, 174.6±5.40 cm; weight, 65.4±5.71 kg; age, 22.7±2.90 yr) participated. The local sweat onset time was delayed in the after-SA compared to that in the before-SA (p<0.001). The local sweat rate and whole body sweat loss volume decreased in the after-SA compared to those in the before-SA (p<0.001). In addition, evaporative loss volume decreased significantly in the after-SA compared to that in the before-SA [chest, upper-back, thigh and forearm (p<0.001)]. Changes in tympanic temperature and mean body temperature were significantly lower (p<0.05) and the basal metabolic rate decreased significantly in the after-SA compared to those in the before-SA (p<0.001). These results suggest that maintenance of a lower body temperature and basal metabolic rate can occur and blunt the central sudomotor mechanisms following seasonal acclimatization, which suppresses sweating sensitivity.     

Rectal,telemetry pill and tympanic membrane thermometry during exercise heat stress

We compared the accuracy of an ingestible telemetry pill method of core temperature (T_c) measurement and an infrared tympanic membrane thermometer to values from a rectal thermistor during exercise-induced heat stress. Ten well-trained subjects completed four exercise trials consisting of 40 min constant-load exercise at 63% of maximum work rate followed by a 16.1 km time trial at 30 °C and 70% relative humidity. Temperature at rest was not different between the three methods of T_c measurement (T_re: 37.2±0.3 °C; T_p: 37.2±0.2 °C; T_ty: 37.1±0.3 °C; P=0.40$P=0.40$). Temperature rose continuously during the exercise period (ΔT_re: 2.2±0.5 °C; ΔT_p: 2.2±0.5 °C; ΔT_ty: 1.9±0.5 ±°C and there were no differences between T_re and T_p measurements at any time throughout exercise (P=0.32$P=0.32$). While there were no differences between T_re and T_ty after 10 min (P=0.11$P=0.11$) and 20 min (P=0.06$P=0.06$) of exercise, T_ty was lower than T_re after 30 min of exercise (P<0.01$P<0.01$) and remained significantly lower throughout the remainder of the exercise period. These results demonstrate that the telemetry pill system provides a valid measurement of trunk temperature during rest and exercise-induced thermal strain. T_ty was significantly lower than T_re when temperature exceeded 37.5 °C. However, whether these differences are due to selective brain cooling or imperfections in the tympanic membrane thermometer methodology remains to be determined.     

Thermopreference,tolerance and metabolic rate of early stages juvenile Octopus maya acclimated to different temperatures

Thermopreference, tolerance and oxygen consumption rates of early juveniles Octopus maya (O. maya; weight range 0.38–0.78 g) were determined after acclimating the octopuses to temperatures (18, 22, 26, and 30 °C) for 20 days. The results indicated a direct relationship between preferred temperature (PT) and acclimated temperature, the PT was 23.4 °C. Critical Thermal Maxima, (CTMax; 31.8±1.2, 32.7±0.9, 34.8±1.4 and 36.5±1.0) and Critical Thermal Minima, (CTMin; 11.6±0.2, 12.8±0.6, 13.7±1.0, 19.00±0.9) increased significantly (P<0.05) with increasing acclimation temperatures. The endpoint for CTMax was ink release and for CTMin was tentacles curled, respectively. A thermal tolerance polygon over the range of 18–30 °C resulted in a calculated area of 210.0 °C². The oxygen consumption rate increased significantly α=0.05 with increasing acclimation temperatures between 18 and 30 °C. Maximum and minimum temperature quotients (Q₁₀) were observed between 26–30 °C and 22–26 °C as 3.03 and 1.71, respectively. These results suggest that O. maya has an increased capability for adapting to moderate temperatures, and suggest increased culture potential in subtropical regions southeast of México.     

Heat coma and its relationship to ocean dynamics in the oceanic sea skaters of Halobates (Heteroptera: Gerridae) inhabiting Indian and Pacific Oceans

This study was performed to clarify how weather and current dynamics affect the resistance to temperature change in the oceanic sea skaters, Halobates. Heat coma temperature (HCT) was measured for the adults and 5th instar larvae of four Halobates species collected from a fixed sampling location (12°00′N, 135°00′E ) in western tropical Pacific Ocean and from 13 locations in the eastern area of the India Ocean ranging from 08°00′N-06°00′S and 86°00-76°00′E. Both the gap temperature for heat coma (GTHC, mean±SD: 7.83±1.86 °C, n=32) and the heat coma temperature (HCP, 35.03±1.80 °C, n=32) of individuals collected from the Pacific Ocean, during the first half (10 days) of the sampling period at the fixed sampling point, were significantly higher than those during the second half (GTHC: 5.10±2.05 °C, n=63; HCP: 34.03±2.02 °C, n=63). The reduction in heat tolerance shown in the second half of the 20 day period may have been caused by a decrease in air temperature due to rainfall that occurred around the sampling point accompanied with the arrival of Typhoon No. 6.In the study of individuals collected from the Indian Ocean, significantly higher average GTHCs of >8 °C were recorded for the adult H. micans collected at 02°00′S and 06°00′S (89°00′E) than those at 0°00-8°00′N in the eastern Indian Ocean. Dynamic mixture of water from northern and southern currents occurs at 02°00-6°00′S of the Indian Ocean and might relate to such high heat tolerance.Temperature dynamics in the ocean habitat might directly affect the temperature resistance of the oceanic sea skaters.     

11β-Hydroxysteroid dehydrogenase activity in acromegalic patients with normal or impaired carbohydrate metabolism

The 11β-hydroxysteroid dehydrogenase isoenzymes (11β-HSD) catalyse the interconversion of cortisol (F) and cortisone (E). Earlier studies demonstrated that growth hormone (GH) and insulin resistance may exert opposite effects on the conversion of E to F by 11β-HSD type 1. Therefore, in the present study we determined F and E concentrations in 562 plasma samples obtained from acromegalic patients during an active phase (76 patients) and after cure of the disease (68 patients). In addition, we examined whether type 2 diabetes mellitus or impaired glucose tolerance, which are frequently associated with active acromegaly could influence plasma F and E levels in these patients. We found that plasma F concentrations were similar in patients with active acromegaly and in those who were cured with pituitary surgery, irradiation and/or medical therapy (mean ± S.E., 12.4 ± 0.3 and 12.7 ± 0.4 μg/dl, respectively). However, plasma E levels were significantly higher in patients with active compared to those with cured acromegaly (2.8 ± 0.1 and 2.2 ± 0.1 μg/dl, respectively; p < 0.001), resulting in a lower F/E ratio in patients with active disease (4.6 ± 0.1 vs. 5.9 ± 0.2 in the cured group of patients; p < 0.001). When the effect of altered carbohydrate homeostasis on plasma F and E was analysed, the results indicated significantly lower plasma E levels and higher F/E ratios in active acromegalic patients with type 2 diabetes mellitus or impaired glucose tolerance compared to those with normal carbohydrate metabolism (E, 2.5 ± 0.1 and 3.0 ± 0.1 μg/dl, respectively; F/E, 5.1 ± 0.2 and 4.4 ± 0.1; p < 0.001), whereas plasma F concentrations were similar in these two groups (12.1 ± 0.4 and 12.6 ± 0.3 μg/dl, respectively). These findings indicate that disease activity exerts a significant impact on 11β-HSD in acromegalic patients, which is further modified with altered carbohydrate homeostasis, frequently present in patients with active disease.     

Rapid thermal responses and thermal tolerance in adult codling moth Cydia pomonella (Lepidoptera: Tortricidae)

In order to preserve key activities or improve survival, insects facing variable and unfavourable thermal environments may employ physiological adjustments on a daily basis. Here, we investigate the survival of laboratory-reared adult Cydia pomonella at high or low temperatures and their responses to pre-treatments at sub-lethal temperatures over short time-scales. We also determined critical thermal limits (CTLs) of activity of C. pomonella and the effect of different rates of cooling or heating on CTLs to complement the survival assays. Temperature and duration of exposure significantly affected adult C. pomonella survival with more extreme temperatures and/or longer durations proving to be more lethal. Lethal temperatures, explored between −20 °C to −5 °C and 32 °C to 47 °C over 0.5, 1, 2, 3 and 4 h exposures, for 50% of the population of adult C. pomonella were −12 °C for 2 h and 44 °C for 2 h. Investigation of rapid thermal responses (i.e. hardening) found limited low temperature responses but more pronounced high temperature responses. For example, C. pomonella pre-treated for 2 h at 5 °C improved survival at −9 °C for 2 h from 50% to 90% (p < 0.001). At high temperatures, pre-treatment at 37 °C for 1 h markedly improved survival at 43 °C for 2 h from 20% to 90% (p < 0.0001). We also examined cross-tolerance of thermal stressors. Here, low temperature pre-treatments did not improve high temperature survival, while high temperature pre-treatment (37 °C for 1 h) significantly improved low temperature survival (−9 °C for 2 h). Inducible cross-tolerance implicates a heat shock protein response. Critical thermal minima (CTmin) were not significantly affected by cooling at rates of 0.06, 0.12 and 0.25 °C min⁻¹ (CTmin range: 0.3-1.3 °C). By contrast, critical thermal maxima (CTmax) were significantly affected by heating at these rates and ranged from 42.5 to 44.9 °C. In sum, these results suggest pronounced plasticity of acute high temperature tolerance in adult C. pomonella, but limited acute low temperature responses. We discuss these results in the context of local agroecosystem microclimate recordings. These responses are significant to pest control programmes presently underway and have implications for understanding the evolution of thermal tolerance in these and other insects.     

Cold resistance in two species of cave-dwelling beetles (Coleoptera: Cholevidae)

Supercooling points (SCPs), lower lethal temperatures (LLTs), and the effect of short-term exposures (1 min) to low temperatures were examined in the adults of two stenothermal leptodirin species, Neobathyscia mancinii and Neobathyscia pasai (Coleoptera, Cholevidae). Specimens were collected from two caves in the Venetian Prealps (NE-Italy). Inter-species comparison highlighted lower values of SCP in N. mancinii (−7.1±0.9 °C) than in N. pasai (−6.4±0.3 °C), with no significant intersexual differences in both species. N. pasai (LLT₅₀±SE=−16.96±2.30 °C; LLT₁₀₀=−25.41 °C) tolerated short exposures to subzero temperatures better than N. mancinii (LLT₅₀±SE=−4.89±1.08 °C; LLT₁₀₀=−11.72 °C). According to the mortality and cumulative proportion of individual freezing curves (CPIF), SCPs and LLT₁₀₀, N. pasai may be defined as “strongly freeze tolerant”, N. mancinii as “moderately freezing tolerant”. Overall, these results may justify the different in-cave habitat selection showed by the two species (N. pasai was abundant close to the entrance where the temperature is variable whereas N. mancinii was confined to the internal part of the cave where the temperature is constant throughout the year), and suggest hypotheses on the effects of such habitat selection on freeze tolerance strategy adopted. Finally, they give new insights into possible responses to climate changes in cave dwelling species.     

Effects of trehalose-loaded liposomes on red blood cell response to freezing and post-thaw membrane quality

We are investigating the use of liposomes, which are synthetic, microscopic vesicles, for the intracellular delivery of trehalose into mammalian cells. This study focuses on the effects trehalose-containing liposomes improve the recovery and membrane quality of human RBCs following cryopreservation. Unilamellar liposomes consisting of a lipid bilayer composed of DPPC, PS and cholesterol (60:30:10 mol%) were synthesized using an extrusion method. Liposome-treated RBCs (l-RBCs) were resuspended in either physiological saline, 0.3 M trehalose or liposome solution, then cooled with slow (0.95 ± 0.02 °C/min), medium (73 ± 3 °C/min) and fast (265 ± 12 °C/min) cooling rates and storage in liquid nitrogen, followed by a 37 °C thawing step. RBC post-thaw quality was assessed using percent recovery, RBC morphology, PS and CD47 expression. Liposome treatment did not adversely affect the RBC membrane. Post-thaw recovery of l-RBCs was significantly higher (66% ± 5% vs 29% ± 4%) compared to control RBCs (c-RBC, p = 0.003). Medium and high cooling rates resulted in significantly higher cell recovery compared to a slow cooling rate (p = 0.039 and p = 0.041, respectively). The recovery of l-RBCs frozen in liposome solution and trehalose solution was significantly higher than that of l-RBCs frozen in NaCl solution for all three cooling rates (p = 0.021). Flow cytometry and morphology assessment showed that liposome treatment resulted in improved post-thaw membrane quality. There was no statistically significant difference in the post-thaw recovery between RBCs treated with liposomes containing trehalose in their aqueous core and RBCs treated with liposomes containing saline in their aqueous core (p = 0.114). Liposome treatment significantly improves the recovery and membrane integrity of RBCs following low temperature exposure.     

Relationship between change in core temperature and change in cortisol and TNFα during exercise

The combined thermal load created by exercise and a hot environment is associated with an exaggerated core temperature response. The elevated core temperature is believed to increase the total stress of the exercise. Increased stress during exercise has been associated with increased levels of cortisol. The association of cortisol with increased inflammatory responses following exercise in the heat is equivocal. Thus, the purpose of the current investigation was to explore the relationship between increases in rectal temperature (T_re) and TNFα and cortisol. To induce T_re changes, 8 male subjects (mean±SD, age=23.6±2 yr, VO₂max=52.8±3.7 mL/kg/min, BMI=24.2±1.9) participated in two 40 min trials of cycle ergometry at 65% of VO₂peak immersed to chest level in cool (25 °C) and warm (38.5 °C) water. T_re was monitored throughout each trial, with blood samples taken immediately pre and post of each trial. Neither cortisol nor TNFα changed significantly during exercise in the cool water; however, in the warm trial, both cortisol and TNFα significantly increased (p<0.004). Concordance correlations (R_c) between Δ cortisol and Δ TNFα indicated a strong but non-significant correlation (R_c=0.833, p=0.135). In conclusion, changes in core temperature may be impacting the relationship between exercise induced changes in cortisol and TNFα. Therefore, acute moderate-intensity exercise (40 min or less) in warm water impacts the stress and inflammatory response. Understanding this is important because exercise load may need to be adjusted in warm and hot environments to avoid the negative effects of elevated stress and inflammation response.     

Conformational behavior of α-d-mannopyranosyl-(1→6)-α,β-d-mannose complexed with two mannose-binding plant lectins, Allium sativam agglutinin I and concanavalin A, using NMR and molecular modeling techniques

Herein, we report the intrinsic conformational preferences of α-d-Manp-(1→6)-α,β-d-Manp, (1) in the free state and as two (ASAI and ConA) lectin-bound forms. NMR spectroscopy and molecular dynamics techniques are used as 3D-structural determination tools. In free form disaccharide 1 displays a fair amount of conformational freedom, with one major (?/ψ 95 ± 30°/195 ± 20°) and one minor (95 ± 30°/70 ± 20°) conformations around the glycosidic linkage and around the ω angle, both the gg and gt rotamers are almost equally populated. This is a first report of a three-dimensional structure of 1 bound with ASAI. Both lectins recognize a major ?/ψ 95 ± 30°/200 ± 30° conformer with the ligand showing more flexibility in the binding site of ConA. Comparison of the mode of binding of the two lectins explains the differences in observed specificities.     

Ambient temperature modulates the magnitude of LPS-induced fevers in Pekin ducks

The consequences of variations in environmental temperature on innate immune responses in birds are by and large not known. We investigated the influence of ambient temperature on the febrile response in female Pekin ducks (Anas platyrhynchos). Ducks, implanted with temperature data loggers to measure body temperature, were injected with lipopolysaccharide (100 μg kg⁻¹) to evoke febrile responses and kept at ambient temperatures higher, within, and lower than their thermoneutral zone (n=10), and in conditions that simulated one day of a heat wave (n=6). Compared to the febrile response at thermoneutrality, at low temperatures, febrile responses were significantly attenuated; fevers reached lower magnitudes (from basal body temperature of 41.2±0.3 °C to a peak of 42.0±0.3 °C). In contrast, at high ambient temperatures, ducks rapidly developed significantly enhanced fevers, which reached markedly higher febrile peaks (from basal body temperature of 41.6 °C to a peak of 44.0 °C in a simulated heat wave when ambient temperature reached 40 °C). These results indicate that ambient temperature affects the febrile response in female Pekin ducks. Our findings reveal a key difference in febrile mediation between ducks and mammals, and have implications for avian survival because high environmental temperatures during febrile mediation could lead to febrile responses becoming physiologically deleterious.     

Testicular gene expression in male mice divergent for fertility after heat stress

Fertility losses in male mice occur approximately 18-28 d after heat stress. The objective of this study was to identify gene expression differences in males highly versus lowly fertile after heat stress. Mature male mice were exposed to heat stress (35 ± 1 °C; n = 50) or thermoneutral (21 ± 1 °C; n = 10) conditions for 24 h (Day 0) and hemicastrated (Day 1) to collect tissue for gene expression analyses. Males were subjected to a mating test from Days 18 to 26 when variation in fertility was anticipated. A fertility index was used to rank heat-stressed males and identify those males resistant and susceptible to heat stress, respectively. Microarray analyses were conducted on testis tissues from control (n = 5), heat stress resistant (n = 5), and heat stress susceptible (n = 5) males, and 225 genes were observed to be differentially expressed (P < 0.05), including genes involved in chaperone (Canx, Hspcb1, and Tcp1) and catalytic (Fkpb6, Psma7, and Idh1) activity. Expression patterns of these genes were confirmed using real-time RT-PCR. Male progeny from selected sires were similarly divergent in fertility after heat stress. Testicular expression levels of Canx, Hspcb, and Tcp1 genes were determined in these progeny. Hspcb expression was moderately heritable (0.31 ± 0.25); however, expression patterns of Canx and Tcp1 were not heritable.     

Estrogen receptor expression and vessel density in the vagina wall in postmenopausal women with prolapse

After menopause, critically estrogen low levels result in modifications in vaginal wall. This cross-sectional study aims to determine whether there is a change in the number of vessels in the lamina propria of the vagina after menopause in parallel to the ER-alpha expression on the vaginal wall. Twelve women who underwent a genital surgery for genital prolapse up to grade II were selected. They were divided into two groups: a premenopausal group (PG) consisting of six women who were 18–40 years old with FSH levels =12 mIU/ml and regular cycles, and a menopausal group (MG) consisting of six women at least one year after menopause who were <65 years old with FSH levels =40 mIU/ml. Slides were stained for ER-alpha immunohistochemistry, and an endothelial cell marker CD3 was used to label vessels which were identified by using a system for morphometry. The number of vessels was significantly higher in the PG than in the MG both on the anterior wall (PG: 1.055 ± 145.8 vessels/mm², MG: 346.6 ± 209.9 vessels/mm², p < 0.0001) and on the posterior wall (PG: 1064 ± 303.3 vessels/mm², MG: 348.6 ± 167.3 vessels/mm², p = 0.0005). The ER-alpha score was significantly higher in the PG than the score for the MG on both the anterior and posterior walls (PG: 6.0 ± 0.52, MG: 2.5 ± 0.89, p = 0.007; PG: 5.8 ± 0.79, MG: 2.7 ± 0.95, p = 0.03, respectively). There was a positive correlation between the ER-alpha score and the vessel concentration on the anterior (r = 0.6656, p = 0.018) and posterior (r = 0.6738, p = 0.016) vaginal walls. Age was strongly negatively correlated with vessel concentration on the vaginal walls (respectively r = -0.9033, p < 0.0001, r = -0.7440, p = 0.0055). Therefore, postmenopausal women with genital prolapse have a smaller number of vessels on the vaginal wall compared to normoestrogenic controls with the same pathological condition. Hypoestrogenism and advancing age are factors that are associated to these changes.     

Effects of vitamin E on diurnal variation in rectal temperature of Black Harco pullets during the hot-dry season

Experiments were performed with the aims of determining rectal temperature (RT) fluctuations in pullets, and the effect of vitamin E administration on the fluctuations during the hot-dry season. The RT values in experimental pullets administered vitamin E orally at a daily dose of 30 mg/kg, were significantly (P<0.05) lower than that of control pullets administered only water (41.21±0.02 and 41.43±0.04 °C, respectively). The dry-bulb temperature was significantly (P<0.001) and positively correlated with RT in both experimental (r=0.800) and control (r=0.936) pullets. Vitamin E administration ameliorated the heat stress of the hot-dry season, and may enhance productivity of pullets during the season.     

Evaporative water loss and energy metabolic in two small mammals,voles (Eothenomys miletus) and mice (Apodemus chevrieri), in Hengduan mountains region

Evaporative water loss (EWL) and energy metabolism were measured at different temperatures in Eothenomys miletus and Apodemus chevrieri in dry air. The thermal neutral zone (TNZ) of E. miletus was 22.5–30 °C and that of A. chevrieri was 20–27.5 °C. Mean body temperatures of the two species were 35.75±0.5 and 36.54±0.61 °C. Basal metabolic rates (BMR) were 1.92±0.17 and 2.7±0.5 ml O₂/g h, respectively. Average minimum thermal conductance (C_m) were 0.23±0.08 and 0.25±0.06 ml O₂/g h °C. EWL in E. miletus and A. chevrieri increased with the increase in temperature; the maximal EWL at 35 °C was 4.78±0.6 mg H₂O/g h in E. miletus, and 5.92±0.43 mg H₂O/g h in A. chevrieri. Percentage of evaporative heat loss to total heat production (EHL/HP) increased with the increase in temperature; the maximal EHL/HP was 22.45% at 30 °C in E. miletus, and in A. chevrieri it was 19.96% at 27.5 °C. The results may reflect features of small rodents in the Hengduan mountains region: both E. miletus and A. chevrieri have high levels of BMR and high levels of total thermal conductance, compared with the predicted values based on their body masses, while their body temperatures are relatively low. EWL plays an important role in temperature regulation.