Thermoregulation of alpacas bred in Italy

The present study monitored daily and seasonal variations of rectal temperature in response to different environmental temperatures in alpacas bred in the Italian Apennines at 300 m a.s.l. In each season, the rectal temperature of 33 clinically healthy alpacas was measured three times/day (morning, midday, afternoon). Ambient temperatures were also recorded. Rectal temperatures ranged from a minimum value of 35.1 to a maximum of 39.4°C, with a maximum daily thermal excursion (ΔT_rec) of 3.2°C. Temperatures increased throughout the day, with highly significant differences recorded in both young and adult animals between all the time bands (P < 0.001). These differences were particularly dramatic for adults in summer, when the mean rectal temperature in the morning was 36.3 ± 0.13°C, probably as a consequence of recent shearing. Significant ΔT_rec differences were recorded depending on the season in both young and adult animals (P < 0.001), with the highest ΔT_rec values recorded in summer (although the highest daily ambient excursion value was recorded in winter). In conclusion, similarly to alpacas bred in their natural environment, alpacas bred in Italy show a wide thermal neutrality zone, which is probably an adaptive response, that allows the animals to save energy. In the Italian Apennines, in order to prevent situations of hypothermia, with possible detrimental effects on alpacas’ health and welfare, shearing should be carried out only in warm seasons.     

The effect of body weight on some welfare indicators in feedlot cattle in a hot environment

Heat stress has important effects on the welfare of livestock. The effects of heat stress in cattle include changes in biological functions and behaviors. The aim of this study was to investigate the behavioral differences between light and heavy feedlot cattle reared in a hot environment. Sixteen male Holstein feedlot cattle were allocated to light (353.8 ± 15.5 kg, n = 8) and heavy (737.1 ± 15.8 kg, n = 8) groups according to their live weight and were kept in a semi-open feedlot barn. The individual behavioral response variables measured were standing, lying, feeding, drinking, ruminating, locomotor activity and elimination (urinating and defecating). The effects of group, day, observation time, replicate and all interactions were included in an explanatory statistical (GLM) model. The data were analyzed using the PROC GLM procedure of SAS. Overall, the heavy cattle spent more time standing (P < 0.001), lying (P < 0.001), and eliminating (P < 0.05) compared to the light group. In contrast, the light group spent more time eating, drinking and ruminating (P < 0.001). Locomotor activity did not differ significantly between groups (P > 0.05). During the day, heavy cattle spent more time standing (at 1600 hours) and less time eating in comparison with the light cattle (P < 0.001) (at 1300 and 1600 hours). Light and heavy feedlot cattle behaved differently in a hot environment. The findings of the study indicate that the welfare of the heavy Holstein feedlot cattle was impacted negatively when the ambient temperature was high (at 1300 hours).     

Tropical Malaysians and temperate Koreans exhibit significant differences in sweating sensitivity in response to iontophoretically administered acetylcholine

Natives of the tropics are able to tolerate high ambient temperatures. This results from their long-term residence in hot and often humid tropical climates. This study was designed to compare the peripheral mechanisms of thermal sweating in tropical natives with that of their temperate counterparts. Fifty-five healthy male subjects including 20 native Koreans who live in the temperate Korean climate (Temperate-N) and 35 native tropical Malaysian men that have lived all of their lives in Malaysia (Tropical-N) were enrolled in this study after providing written informed consent to participate. Quantitative sudomotor axon reflex testing after iontophoresis (2 mA for 5 min) with 10% acetylcholine (ACh) was used to determine directly activated (DIR) and axon reflex-mediated (AXR) sweating during ACh iontophoresis. The sweat rate, activated sweat gland density, sweat gland output per single gland activated, and oral and skin temperature changes were measured. The sweat onset time of AXR (nicotinic-receptor-mediated) was 56 s shorter in the Temperate-N than in the Tropical-N subjects (P < 0.0001). The nicotinic-receptor-mediated sweating activity AXR (1), and the muscarinic-receptor-mediated sweating activity DIR, in terms of sweat volume, were 103% and 59% higher in the Temperate-N compared to the Tropical-N subjects (P < 0.0001). The Temperate-N group also had a 17.8% (P < 0.0001) higher active sweat gland density, 35.4% higher sweat output per gland, 0.24°C higher resting oral temperature, and 0.62°C higher resting forearm skin temperature compared to the Tropical-N subjects (P < 0.01). ACh iontophoresis did not influence oral temperature, but increased skin temperature near where the ACh was administered, in both groups. These results suggest that suppressed thermal sweating in the Tropical-N subjects was, at least in part, due to suppressed sweat gland sensitivity to ACh through both recruitment of active sweat glands and the sweat gland output per each gland. This physiological trait guarantees a more economical use of body fluids, thus ensuring more efficient protection against heat stress.     

Assessing the heat tolerance of 17 beef cattle genotypes

Cattle production plays a significant role in terms of world food production. Nearly 82% of the world’s 1.2 billion cattle can be found in developing countries. An increasing demand for meat in developing countries has seen an increase in intensification of animal industries, and a move to cross-bred animals. Heat tolerance is considered to be one of the most important adaptive aspects for cattle, and the lack of thermally-tolerant breeds is a major constraint on cattle production in many countries. There is a need to not only identify heat tolerant breeds, but also heat tolerant animals within a non-tolerant breed. Identification of heat tolerant animals is not easy under field conditions. In this study, panting score (0 to 4.5 scale where 0 = no stress and 4.5 = extreme stress) and the heat load index (HLI) [HLI_BG<25°C = 10.66 + 0.28 × rh + 1.30 × BG – WS; and, HLI _{BG> 25°C} = 8.62 + 0.38 × rh + 1.55 × BG – 0.5 × WS + e^{(2.4 – WS)}, where BG = black globe temperature (^oC), rh = relative humidity (decimal form), WS = wind speed (m/s) and e is the base of the natural logarithm] were used to assess the heat tolerance of 17 genotypes (12,757 steers) within 13 Australian feedlots over three summers. The cattle were assessed under natural climatic conditions in which HLI ranged from thermonuetral (HLI < 70) to extreme (HLI > 96; black globe temperature = 40.2°C, relative humidity = 64%, wind speed = 1.58 m/s). When HLI > 96 a greater number (P < 0.001) of pure bred Bos taurus and crosses of Bos taurus cattle had a panting score ≥ 2 compared to Brahman cattle, and Brahman-cross cattle. The heat tolerance of the assessed breeds was verified using panting scores and the HLI. Heat tolerance of cattle can be assessed under field conditions by using panting score and HLI.     

Muscle strength and soft tissue composition as measured by dual energy x-ray absorptiometry in women aged 18–87 years

Dual energy x-ray absorptiometry (DEXA) offers the possibility of assessing regional soft tissue composition, i.e. lean mass (LM) and fat mass : LM may be considered a measure of muscle mass. We examined age-related differences in LM, percentage fat (%fat) and muscle strength in 100 healthy non-athletic women aged 18–87 years. Relationships between muscle strength and leg LM in 20 elite female weight lifters and in 18 inactive women with previous hip fractures were also studied. The LM and %fat of the whole body, trunk, arms and legs were derived from a whole body DEXA scan. Isokinetic knee extensor strength (KES) and flexor strength (KFS) at 30° · s^–1 were assessed using an isokinetic dynamometer. The women aged 71–87 years had 35% lower KES and KFS than the women aged 18–40 years (P < 0.0001). Differences in LM were less pronounced. The LM of the legs, for instance, was 15% lower in the old than in the young women (P < 0.0001). In a multiple regression analysis with age, body mass, height and leg LM or KES as independent variables and KES or leg LM as the dependent variable, age was the most important predictor of KES (r _partial = −0.74, P < 0.0001). The same applied to KFS. Body mass, not age, was the most important predictor of leg LM (r _partial = 0.65, P < 0.0001) and of LM at all other measurement sites. The LM measured at different regions decreased equally with increasing age. The KES:leg LM ratio was negatively correlated with age (r = −0.70, P < 0.0001). The weight lifters had significantly higher KES:leg LM ratios than age-matched controls (+12%, P < 0.0001) and vice versa for the women with previous hip fractures (–36%, P < 0.0001). In conclusion, from our study it would seem that in healthy nonathletic women, age is a more important determinant of muscle strength than is LM as measured by DEXA. Muscle strengthening exercises and inactivity seem to have a considerably stronger influence on muscle strength than on LM. Accepted: 27 August 1996     

Behaviour of interleukin-2 serum levels in advanced non-small-cell lung cancer patients: relationship with response to therapy and survival

 Interleukin(IL)-2 is a T helper (Th) 1 type cytokine that has been shown to play an important role in antitumour immune responses. In this study, the prognostic significance of serum IL-2 levels was investigated in 60 advanced non-small-cell lung cancer (NSCLC) patients. IL-2 serum levels were determined before chemotherapy, at the end of chemotherapy and during follow-up, using a commercially available enzyme-linked immunoadsorbent assay kit. The results were analysed according to the response to therapy and were used to generate a model predicting overall survival and time to treatment failure. All 60 patients were shown to have higher IL-2 serum levels than controls (P < 0.0001). Stage IV patients had significantly lower IL-2 levels than stage III patients (P < 0.0001), although they were still significantly higher than controls (P < 0.0001). It is interesting that, when patients were divided into responders and non-responders according to the response to therapy, the former were shown to have significantly higher pre-chemotherapy levels than the latter (P < 0.0001). Moreover, a further significant increase in IL-2 serum levels (P=0.004) and a significant decrease (P < 0.0001) were shown in responders and non-responders, respectively at the end of the therapy. Using univariate and multivariate analyses, both overall survival and time to treatment failure were shown to be affected by the mean pathological levels of IL-2. Furthermore, the prognostic significance of the serum level of IL-2 was confirmed by the stepwise regression analysis. In conclusion, determination of pre-treatment IL-2 serum levels was shown to be of independent prognostic utility in patients with advanced NSCLC; therefore, its possible use for prediction of outcome is proposed. Received: 16 March 2000 / Accepted: 27 July 2000     

Occurrence of aflatoxin in three maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) hybrids over 5 years in Northern Mississippi

Aflatoxins are produced as secondary metabolites under conducive climatic conditions by Aspergillus flavus. The incidence of aflatoxin varies with environmental conditions, genotype, and location. An expanded understanding of the interaction of the plant, fungus, and weather conditions is needed to further elucidate the field infection process of maize by A. flavus and subsequent aflatoxin contamination. One of the problems in evaluating maize hybrids for resistance to kernel infection and aflatoxin contamination is identifying a time period and environmental conditions that are most advantageous. Three maize genotypes (Pioneer Brand 3223, Mo18W × Mp313E, and Mp313E × Mp420) were evaluated from 1998 to 2002 in response to A. flavus inoculation and aflatoxin contamination and weather conditions favorable for aflatoxin contamination were identified. The highest aflatoxin levels were observed in 1998 and 2000 (1186 and 901 ng g⁻¹; P < 0.0001); while the lowest levels were detected in 1999 (39 ng g⁻¹). Pioneer 3223 had significantly higher levels (1198 ng g⁻¹) than Mp313E × Mp420 (205 ng g⁻¹), and Mo18W ×Mp313E (161 ng g⁻¹; P < 0.0001). The hybrids had six weather-related variables in common that were positively correlated with aflatoxin accumulation. Four of these occurred during 65–85 days after planting and were temperature-related. These results suggest that regardless of the hybrid’s maturity or physiological development, the time from 65 to 85 days after planting may be indicative of a period of stress which leads to greater aflatoxin accumulation at harvest. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Copper and Liver Function Indicators Vary Depending on the Female Hormonal Cycle and Serum Hormone Binding Globulin (SHBG) Concentration in Healthy Women

Previous studies showed that responses to chronic administration of copper were significantly associated with gender, raising the need to better characterize the relation between the effects observed and stradiols. The objective of this study was to measure copper and liver function indicators and the sex hormone binding globulin (SHBG) serum concentrations in healthy adults exposed to copper, grouped by sex and phase of the female hormonal cycle. Healthy females on day 7 (follicular phase, Group 1, n = 39), on day 21 (secretory phase, Group 2, n = 34) and males (comparison group, Group 3, n = 34) received 8 mg Cu/day (as copper sulfate), orally, for 6 months. On days 0, 30, 60, 120, and 180, the serum concentration of copper, ceruloplasmin, liver aminotransferases, and SHBG were measured. Analysis of results included analysis of variance (ANOVA; repeated measures) and the post hoc Bonferroni correction. Participants remained healthy throughout the study period, including aminotransferases below the cut off in all measures. GGT, AST, and ALT activities were significantly different by group and by time (ANOVA repeated measures P < 0.05). Six-month curves of serum copper and ceruloplasmin concentrations were different by group, by time and interaction group × time (all P < 0.001). SHBG curves were different by group and time (P < 0.01), and interaction group × time (P < 0.009). Serum copper, ceruloplasmin, and liver aminotranferases are influenced by estrogens/progesterone, something that should be considered when these indicators are used as outcomes of effects. Time of sampling was also significantly associated with the indicators and deserves further study.     

The time-profile of the PBMC HSP70 response to in vitro heat shock appears temperature-dependent

Summary. Heat shock proteins (HSPs) are synthesised by cells subsequent to a stress exposure and are known to confer protection to the cell in response to a second challenge. HSP induction and decay are correlated to thermotolerance and may therefore be used as a biomarker of thermal history. The current study tested the temperature-dependent nature of the heat shock response and characterised its time profile of induction. Whole blood from 6 healthy males (Age: 26 ± (SD) 2 yrs; Body mass 74.2 ± 3.8 kgs; VO_2max: 49.1 ± 4.0 ml·kg⁻¹·min⁻¹) were isolated and exposed to in vitro heat shock (HS) at 37, 38, 39, 40, and 41 °C for a period of 90 min. After HS the temperature was returned to 37 °C and intracellular HSP70 was quantified from the leukocytes at 0, 2, 4, and 6 h after heat treatment. The concentration of HSP70 was not different between temperatures (P > 0.05), but the time-profile of HSP70 synthesis appeared temperature-dependent. At control (37 °C) and lower temperatures (38–39 °C) the mean HSP70 concentration increased up to 4 h post HS (P < 0.05) and then returned towards baseline values by 6 h post HS. With in vitro hyperthermic conditions (40–41 °C), the time-profile was characterised by a sharp rise in HSP70 levels immediately after treatment (P < 0.05 for 40 °C at 0 h), followed by a progressive decline over time. The results suggest a temperature-dependent time-profile of HSP70 synthesis. In addition, the temperature at which HSP70 is inducted might be lower than 37 °C.     

Supplementation with organic or inorganic selenium in heat-distressed quail

The present study was carried out to determine the effects of different sources of selenium (Se; sodium selenite [Na₂SeO₃] or selenomethionine [Se-Met]) supplementation on egg production, egg quality, levels of malondialdehyde (MDA), and Se in serum and egg yolk in heat-stressed Japanese quail (Coturnix coturnix japonica). The birds (n = 360; 55 days old) were randomly assigned to 12 treatment groups consisting of six replicates of five birds each in a 2 × 2 × 3 factorial arrangement of treatments (temperatures, selenium sources, selenium levels). Birds were kept in wire cages in a temperature-controlled room at either 22 (thermoneutral) or 34°C (heat stress) for 8 h/day (09:00–17:00; till the end of study) and fed a basal (control) diet or the basal diet supplemented with either 0.15 or 0.30 mg of Na₂SeO₃ or selenomethionine/kg of diet. Heat exposure decreased live weight, feed intake, feed efficiency, egg production, and egg quality when basal diet was fed (P < 0.0001). A linear increase in feed intake (P = 0.001) and body weight (P = 0.001), egg production (P = 0.001), and improvement in feed efficiency (P = 0.001) and egg quality (P = 0.001) were found in Se-supplemented quail reared under heat stress conditions. Serum, egg white, and egg yolk Se (P ≤ 0.001) concentrations increased linearly, whereas serum, liver, and egg yolk MDA concentrations decreased linearly (P = 0.001) as dietary Na₂SeO₃ or Se-Met supplementation increased. An interaction between dietary Se sources, temperature, and levels of supplementation (P ≤ 0.05) for these parameters was detected. Supplementation with Se improved egg production, egg quality, and antioxidant status of birds, and the effects of Se-Met were relatively greater than Na₂SeO₃ in heat-stressed quail. Results of the present study suggest that supplementation with Se-Met can be considered to be more protective than Na₂SeO₃ by reducing the negative effects of oxidative stress induced by heat stress in quail.     

Selenium Levels in First-Degree Relatives of Diabetic Patients

The present study was conducted to evaluate the serum selenium levels in first-degree relatives of diabetic patients (FDR) according to controls. Insulin resistance, serum lipid levels, inflammation markers, and blood pressure were also studied in these patients. Serum levels of selenium in FDR were significantly lower than control group (74.65 ± 5.9 vs 88.7 ± 8.7 μg/dl, p < 0.0001). HsCRP, HOMA-IR, insulin, homocysteine levels were significantly higher in FDR according to the control group (1.32 ± 0.9 vs 0.63 ± 0.4 mg/dL, p < 0.0001; 2.07 ± 0.84 vs 1.51 ± 0.69, p < 0.0001; 9.26 ± 3.8 vs 6.8 ± 2.98 μU/MI, p < 0.0001; 15.7 ± 7.4 vs 11.5 ± 5.1 μmol/L, p < 0.0001, respectively). There was significant correlation between selenium levels and hsCRP (r = − 0.450, p < 0.0001). There was also weak significant correlation also between HOMA-IR and selenium levels (r = −0.227, p = 0.003). There was a correlation between systolic blood pressure and BMI (r = 0.365, p < 0.0001). But there was no correlation between selenium levels and blood pressure or other parameters. HsCRP, HOMA-IR, homocysteine levels in individuals with selenium levels < 80 μg/L (n = 78) was significantly higher than hsCRP HOMA-IR, homocysteine levels in individuals with selenium levels ≥ 80 (n = 91; 1.23 ± 0.98 vs 0.81 ± 0.76 mg/dL, p < 0.003; 1.99 ± 0.88 vs 1.64 ± 0.74, p < 0.005; 15.0 ± 7.6 vs 12.9 ± 5.7 μmol/L, p < 0.049, respectively). Selenium deficiency may contribute to cardiovascular disease risk in FDR.     

The effect of sodium balance on sweat sodium secretion and plasma aldosterone concentration

The effect of manipulating sodium intake upon sweat sodium secretion was investigated during heat acclimation. Twenty-five male subjects were confined to an environmental chamber at a temperature of 25°C for 3 days, and then acclimated to heat by a further 5 days at 40°C. The subjects' daily sodium intake was controlled throughout as follows: high (HNa), 348.4 (0.8) mmol · day⁻¹, n = 7; moderate (MNa), 174.1 (0.6) mmol · day⁻¹, n = 9; or low (LNa), 66.3 mmol · day⁻¹, n = 9. Sodium losses were estimated from urinary, faecal and sweat collections using a whole-body washdown method. Plasma aldosterone concentration was also measured from venous blood sampled each morning. Measurements of body temperature and heart rate during the heat exposure phase indicated a degree of heat acclimation. During this heat phase there was a reduction (P < 0.01) in sweat sodium secretion for all three conditions which was greatest for the LNa condition, although this finding was not significant (P < 0.1). In the LNa condition, plasma aldosterone concentration increased (P < 0.05) prior to heat exposure, and the secretion of aldosterone was potentiated (P < 0.01) during the heat exposure in comparison with the MNa condition. In contrast, the HNa diet produced a fall (P < 0.05) in plasma aldosterone concentration prior to heat exposure and an attenuation of aldosterone secretion thereafter. These findings are inconsistent with the hypothesis that retention of sweat sodium is dependent upon a net body sodium deficit, but demonstrate that aldosterone secretion is potentiated under such conditions. Accepted: 22 May 1988     

Thermoregulatory responses of paraplegic and able-bodied athletes at rest and during prolonged upper body exercise and passive recovery

The thermoregulatory responses of ten paraplegic (PA; T3/4-L4) and nine able-bodied (AB) upper body trained athletes were examined at rest and during prolonged arm-cranking exercise and passive recovery. Exercise was performed for 90 min at 80% peak heart rate, and at 21.5 (1.7)°C and 47.0 (7.8)% relative humidity on a Monark cycle ergometer (Ergomedic 814E) adapted for arm exercise. Mean peak oxygen uptake values for the PA and AB athlete groups were 2.12 (0.41) min⁻¹ and 3.19 (0.38) l · min⁻¹, respectively (P<0.05). At rest, there was no difference in aural temperature between groups [36.2 (0.4)°C for both groups]. However, upper body skin temperatures for the PA athletes were approximately 1.0 °C warmer than for the AB athletes, whereas lower body skin temperatures were cooler than those for the AB athletes (1.3 °C and 2.7 °C for the thigh and calf, respectively). Upper and lower body skin temperatures for the AB athletes were similar. During exercise, blood lactate peaked after 15 min of exercise for both groups [3.33 (1.26) mmol · l⁻¹ and 4.30 (1.03) mmol · l⁻¹ for the PA and AB athletes, respectively, P<0.05] and decreased throughout the remainder of the exercise period. Aural temperature increased by 0.7 (0.5)°C and 0.6 (0.4)°C for the AB and PA athletes, respectively. Calf skin temperature for the PA athletes increased during exercise by 1.4 (2.8)°C (P<0.05), whereas a decrease of 0.8 (2.0)°C (P<0.05) was observed for the AB athletes. During the first 20 min of recovery from exercise, the calf skin temperature of the AB athletes decreased further [−2.6 (1.3)°C; P<0.05]. Weight losses and changes in plasma volume were similar for both groups [0.7 (0.5) kg and 0.7 (0.4) kg; 5.4 (4.9)% and 9.7 (6.2)% for the PA and AB athletes, respectively]. In conclusion, the results of this study suggest that the PA athletes exhibit different thermoregulatory responses at rest and during exercise and passive recovery to those of upper body trained AB athletes. Despite this, during 90 min of arm-crank exercise in a cool environment, the PA athletes appeared to be at no greater thermal risk than the AB athletes. Accepted: 7 May 1997     

The effect of exercise intensity on hematuria in healthy male runners

The purpose of this study were: (1) to establish the prevalence of exercise-induced hematuria in a group of otherwise healthy male runners (n = 70), and (2) to investigate the role of exercise intensity in those runners who exhibited exercise-related hematuria (n = 10) by evaluating the effect of running and cycling at high and low intensities. The identified and recruited subjects participated in four different exercise protocols: (1) a 60-min treadmill run (RUN) at 90% of anaerobic threshold (Th_ae), (2) a 60-min leg cycle ergometer ride (BIKE) at 90% of Th_ae, (3) a 3×400-m sprint (SPRINT), each followed by 4 min of rest or light walking, and (4) 3×60-Wingate leg cycle ergometry tests, each followed by 4 min of rest or light cycling. The study employed a 3×4 (time by protocol) within-subjects design and dependent variables were measured before exercise, 4 min after, and 1 h after exercise, and included measurements of hematuria, proteinuria, urinary pH, serum haptoglobin concentration, serum creatine phosphokinase activity, plasma lactate concentration, and hemoglobin. The 400-m sprint at maximal effort significantly increased both hematuria and proteinuria (P < 0.01). Post-exercise hematuria for the SPRINT protocol was significantly different than that for the BIKE (P < 0.01) and RUN (P < 0.01) protocols. Due to the significant increase in hematuria and proteinuria following the SPRINT protocol, it was concluded that exercise-related changes in renal function were associated with weight-bearing exercise intensity rather than non-weight-bearing exercise duration. Accepted: 30 April 1998     

The reproductive traits of brown trout (Salmo trutta fario L.) from the Yadong River, Tibet

Some key aspects of the reproductive strategy of the brown trout (Salmo trutta fario L.) in the Yadong River, Tibet, including spawning season, age at sexual maturity, fecundity and egg size, have been studied. The majority of the samples were less than 215 mm and age ranged from 1 to 4 in both sexes, indicating that the majority of the fish were younger and the pressure by overfishing was high. The spawning periodicity was determined to be between the end of October and January, mainly in November and December. The ratio of male to female brown trout population (1.29:1 with P > 0.05) suggested no sex significant differences, although males were significantly more abundant than females in October (P < 0.0001) on monthly basis. Age and size of males and females at maturity was different and males matured earlier than females. Fecundity was markedly correlated with their body weight (P < 0.001, r = 0.9255), standard length (P < 0.01, r = 0.8879), and gonad weight (P < 0.001, r = 0.9366). The mean size of mature eggs in the spawning season was: 4.0 ± 0.45 mm and tended to increase along with the female spawners size (P < 0.001, r = 0.9641). Further researches about the brown trout population in the Yadong River should be conducted on issues such as artificial reproduction, culture, conservation, management, and restocking.     

Oral temperatures of the elderly in nursing homes in summer and winter in relation to activities of daily living

 This study was conducted to clarify the seasonal difference in body temperature in summer and winter, and to document the thermal environment of the elderly living in nursing homes. The subjects were 57 healthy elderly people aged ≥63 years living in two nursing homes in Japan. One of the homes was characterized by subjects with low levels of activities of daily living (ADL). Oral temperatures were measured in the morning and afternoon, with simultaneous recording of ambient temperature and relative humidity. Oral temperatures in summer were higher than in winter, with statistically significant differences (P<0.05) of 0.25 (SD 0.61) °C in the morning and 0.24 (SD 0.50) °C in the afternoon. Differences between oral temperatures in summer and winter tended to be greater in subjects with low ADL scores, even when their room temperature was well-controlled. In conclusion, the oral temperatures of the elderly are lower in winter than summer, particularly in physically inactive people. It appears that those with low levels of ADL are more vulnerable to large changes in ambient temperature. Received: 28 March 1996 / Accepted: 12 November 1996     

Regional differences in sweat rate response of steers to short-term heat stress

Six Angus steers (319 ± 8.5 kg) were assigned to one of two groups (hot or cold exposure) of three steers each, and placed into two environmental chambers initially maintained at 16.5–18.8°C air temperature (T _a). Cold chamber T _a was lowered to 8.4°C, while T _a within the hot chamber was increased to 32.7°C over a 24-h time period. Measurements included respiration rate, and air and body (rectal and skin) temperatures. Skin temperature was measured at shoulder and rump locations, with determination of sweat rate using a calibrated moisture sensor. Rectal temperature did not change in cold or hot chambers. However, respiration rate nearly doubled in the heat (P < 0.05), increasing when T _a was above 24°C. Skin temperatures at the two locations were highly correlated (P < 0.05) with each other and with T _a. In contrast, sweat rate showed differences at rump and shoulder sites. Sweat rate of the rump exhibited only a small increase with T _a. However, sweat rate at the shoulder increased more than four-fold with increasing T _a. Increased sweat rate in this region is supported by an earlier report of a higher density of sweat glands in the shoulder compared to rump regions. Sweat rate was correlated with several thermal measurements to determine the best predictor. Fourth-order polynomial expressions of short-term rectal and skin temperature responses to hot and cold exposures produced r values of 0.60, 0.84, and 0.98, respectively. These results suggest that thermal inputs other than just rectal or skin temperature drive the sweat response in cattle.     

Changes in Morphology and Elemental Composition of <Emphasis Type="Italic">Vibrio splendidus</Emphasis> Along a Gradient from Carbon-limited to Phosphate-limited Growth

We examined morphology, elemental composition (C, N, P), and orthophosphate-uptake efficiency in the marine heterotrophic bacterium Vibrio splendidus grown in continuous cultures. Eight chemostats were arranged along a gradient of increasing glucose concentrations in the reservoirs, shifting the limiting factor from glucose to phosphate. The content of carbon, nitrogen, and phosphorus was measured in individual cells by x-ray microanalysis using a transmission electron microscope (TEM). Cell volumes (V) were estimated from length and width measurements of unfixed, air-dried cells in TEM. There was a transition from coccoid cells in C-limited cultures toward rod-shaped cells in P-limited cultures. Cells in P-limited cultures with free glucose in the media were significantly larger than cells in glucose-depleted cultures (P < 0.0001). We found functional allometry between cellular C-, N-, and P content (in femtograms) and V (in cubic micrometers) in V. splendidus (C = 224 × V ^0.89, N = 52.5 × V ^0.80, P = 2 × V ^0.65); i.e., larger bacteria had less elemental C, N, and P per V than smaller cells, and also less P relative to C. Biomass-specific affinity for orthophosphate uptake in large P-limited V. splendidus approached theoretical maxima predicted for uptake limited by molecular diffusion toward the cells. Comparing these theoretical values to respective values for the smaller, coccoid, C-limited V. splendidus indicated, contrary to the traditional view, that large size did not represent a trade-off when competing for the non-C-limiting nutrients.     

Effects of season on sleep and skin temperature in the elderly

The effects of season on sleep and skin temperature (Tsk) in 19 healthy, elderly volunteers were investigated. Measurements were obtained in summer, winter, and fall, and activity levels were monitored using a wrist actigraph system for five consecutive days. The temperature and humidity of the bedrooms of the subjects’ homes were measured continuously for five days. During actigraphic measurement, Tsk during sleep was measured for two nights. The bedroom temperature and humidity significantly increased in summer compared to winter and fall. In summer, the total sleep time decreased (mean ± SE min; summer, 350.8 ± 15.7; winter, 426.5 ± 14.2; fall, 403.2 ± 16.4) and wakefulness increased (P < 0.003) compared to those in fall or winter. The sleep efficiency index that was derived from wrist actigraphy was significantly decreased (P < 0.001) in summer (81.4 ± 2.9%) compared with winter (91.6 ± 1.3%) or fall (90.2 ± 1.2%). The forehead Tsk significantly increased, while the chest and thigh Tsks were decreased in summer compared to those in fall or winter. These results suggest that, in the elderly, sleep is disturbed in summer more than in other seasons, and that this disturbance is related to fluctuations in Tsk.