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PubMed1998

A comparison of rectal and subcutaneous body temperature measurement in the common marmoset.

Two methods of measuring body temperature were compared in common marmosets. Subcutaneous temperatures were measured remotely via previously implanted subcutaneous microchips (Plexx BV, IPTT-100) prior to measurement of rectal temperature using a conventional rectal probe. Marmosets were treated with saline or the brain penetrant, 5-HT1A/B/D receptor agonist SKF-99101H (3-(2-dimethylaminoethyl)-4-chloro-5-propoxyindole hemifumarate) (0.3-3 mg/kg SC), which has previously been shown to induce hypothermia in guinea pigs. Body temperature was sampled immediately before drug administration and at 30-min intervals thereafter for a period of 2.5 h. SKF-99101H dose-dependently induced hypothermia in the common marmoset and there was close agreement between rectal and subcutaneous body temperatures, with an average difference in absolute body temperature of 0.26+/-0.02 degrees C. The data show that subcutaneously implanted microchips provide a simple, reliable measure of body temperature in common marmosets which is sensitive to pharmacological intervention, minimizes handling induced stress, and is minimally invasive.

Animals↗

PubMed1970

Variations in deep body temperature in the young unrestrained pig over the 24 hour period.

1. The temperature near the carotid artery has been measured in the unrestrained pig by means of radiotelemetry. When the animals were housed singly under constant conditions of temperature and lighting the temperature rhythm appeared to be related only to the time of feeding. A similar record was obtained from temperature measurements made in the hypothalamus.2. Over the range of ambient temperatures 10-30 degrees C the mean body temperature was 38.8 degrees C. No consistent variation occurred with ambient temperature, but on initial transfer from 10 to 30 degrees C ambient temperature the body temperature decreased, while on initial transfer from 30 to 10 degrees C it increased.3. When one pig was housed in a hut with a small outside yard a nychthemeral rhythm was sometimes superimposed on that imposed by feeding. When two pigs were kept in a paddock containing a hut the nychthemeral rhythm was more pronounced.4. It is concluded that in the pig there is very little innate circadian temperature rhythm and that the temperature variations seen are related chiefly to feeding and activity.

Animals↗

PubMed1988

Body temperature response profiles for selective mu, delta and kappa opioid agonists in restrained and unrestrained rats.

In many cases, body temperature is altered in response to opioid agonists, but the direction, magnitude and time course of alteration vary with a number of factors. Body temperature may be subject to differential modification by different opioid receptor types. The authors examined the effect (i.c.v.) of the selective mu, delta and kappa opioid agonists, [D-Ala2, MePhe4, Gly5-ol] enkephalin (DAGO), [D-Pen2, D-Pen5] enkephalin and U50488H, respectively, on the body temperature of restrained and unrestrained rats. Each of the three opioid agonists produced a differentiable profile of body temperature changes. DAGO caused a primary decrease in body temperature of restrained rats and an increase in body temperature of unrestrained rats. The pretreatment dose of naloxone necessary to attenuate the hyperthermic response to DAGO of unrestrained rats was 10 times higher than that required to block the hypothermic response to DAGO in restrained rats. Low doses of both [D-Pen2, D-Pen5]enkephalin and U50488H caused a decrease in body temperature of both restrained and unrestrained rats. Hypothermic responses to U50488H were not blocked by naloxone, whereas hypothermic responses to [D-Pen2, D-Pen5]enkephalin in unrestrained rats were potentiated by naloxone. The results indicate that the three compounds modified body temperature by different means, suggesting activation of different opioid, and perhaps nonopioid, receptors. This may reflect a differential modulation of body temperature by endogenous opioids depending on the specific peptide released and the receptor type activated. Besides the physiologic implications, body temperature responses provided a sensitive pharmacologic measure for distinguishing the in vivo activity of different selective opioid agonists.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

PubMed2005

Brain and body temperature homeostasis during sodium pentobarbital anesthesia with and without body warming in rats.

High-speed, multi-site thermorecording offers the ability to follow the dynamics of heat production and flow in an organism. This approach was used to study brain-body temperature homeostasis during the development of general anesthesia induced by sodium pentobarbital (50 mg/kg, ip) in rats. Animals were chronically implanted with thermocouple probes in two brain areas, the abdominal cavity, and subcutaneously, and temperatures were measured during anesthesia both with and without (control) body warming. In control conditions, temperature in all sites rapidly and strongly decreased (from 36-37 degrees C to 32-33 degrees C, or 3.5-4.5 degrees C below baselines). Relative to body core, brain hypothermia was greater (by 0.3-0.4 degrees C) and skin hypothermia was less (by approximately 0.7 degrees C). If the body was kept warm with a heating pad, brain hypothermia was three-fold weaker ( approximately 1.2 degrees C), but the brain-body difference was significantly augmented (-0.6 degrees C). These results suggest that pentobarbital-induced inhibition of brain metabolic activity is a major factor behind brain hypothermia and global body hypothermia during general anesthesia. These data also indicate that body warming is unable to fully compensate for anesthesia-induced brain hypothermia and enhances the negative brain-body temperature differentials typical of anesthesia. Since temperature strongly affects various underlying parameters of neuronal activity, these findings are important for electrophysiological studies performed in anesthetized animal preparations.

Analysis of Variance↗

PubMed2005

Body temperature and circulating progesterone levels before and after parturition in killer whales (Orcinus orca).

Killer whales were used to evaluate peripartum changes and interactions between body temperature and circulating progesterone concentration. Daily body temperature was measured between 0800 h and 0830 h before activity. Body temperature clearly increased during the first phase of pregnancy, and this was followed by a gradual decline until full term. The initial increase was paralleled by circulating levels of progesterone. A decrease in body temperature was first detected on day 5 (p < 0.01) before parturition, and body temperature decreased significantly every 2 days until delivery. Five days before delivery, body temperature was 0.3 C lower than the mean value during the pregnancy period, and the decrease was more marked on day 1 before delivery (0.8 C). Serum progesterone levels during pregnancy showed a general pattern of initial rapid elevation (increasing phase), followed by a gradual decline (decreasing phase) throughout the remainder of pregnancy. However, statistically significant correlations between body temperature and progesterone pattern were only found only during the increasing phase. These results suggest that monitoring body temperature variation can be considered valuable for predicting impending parturition in killer whales.

Animals↗

PubMed1990

Circadian rhythms in depression. Part I: Monitoring of the circadian body temperature rhythm.

In order to develop a sampling strategy and a method for analyzing the circadian body temperature pattern, we monitored estimates of the temperature in four ways using rectal, oral, axillary and deep body temperature from the skin surface every hour for 72 consecutive hours in 10 normal control subjects. Data obtained were analyzed with the least-squares method to estimate the circadian rhythm. Deep body temperature from the skin surface correlated better with rectal temperature than with either oral or axillary temperature in all subjects. The correlation coefficient between rectal and deep body temperature from the skin surface ranged between 0.66 and 0.89. The acrophases calculated from the deep body temperature from the skin surface every 2 h for 48 h were consistent with those based on the rectal temperature every 10 min for 72 h. We believe that monitoring of the deep body temperature from the skin surface, in this manner, at intervals of 2 h for a period of 2 days, is a promising method for investigating circadian body temperature rhythm, because it causes less discomfort than other measures and has greater statistical validity for data computation.

Adult↗

PubMed1989

Urinary basal body temperature in anorexia nervosa.

Measurements of basal body temperature obtained from first-morning voided urine were followed longitudinally in 23 individuals with anorexia nervosa. In each of 10 hypothermic individuals, we found that basal body temperature was significantly correlated with weight gain, whereas in most normothermic individuals, no relationship was found. This suggests that measurement of basal body temperature may provide a convenient means of assessing clinical improvement and nutritional rehabilitation in some patients with anorexia nervosa. Differences in neuroendocrine measures and weight gain were also studied. Thyroid functions did not differ significantly between groups, and no differences were found in dexamethasone suppression or in the thyrotropin-releasing hormone (TRH) stimulation test. Hypothermic individuals, however, were significantly younger and significantly more likely to gain weight in response to treatment.

Anorexia Nervosa↗

PubMed1992

Effect of body temperature on threshold for retinal light damage.

Body temperature is known to influence the threshold for retinal light damage, but the magnitude of the effect has varied substantially between previous studies. The purpose of the present study was to establish a quantitative relation between body temperature in the range of 30-42 degrees C and dose of radiation for a just visible change in fundo. Anesthetized pigmented rats were exposed to 380 nm radiation for 10 min. Four intensities were simultaneously presented. Funduscopic changes were noted 2-3 d after exposure. At 30 degrees C, threshold dose was 6 J/cm2; at 42 degrees C, it was about 1 J/cm2. A fair fit to the data could be obtained with a linear regression between log threshold dose and temperature. The slope was -0.067. In an additional experiment, threshold dose at 500 nm and 41 degrees C body temperature was established at 400 J/cm2. These results agree with data in monkey and rabbit, but they vary from earlier data in rats that show a slope of -0.8. Exposure time, damage criterion, and the chromophores involved in retinal light damage are possible factors in the discrepancy.

Animals↗

PubMed1992

The changes in body temperature, oxygen consumption, CO2 production and muscle protein turnover rate by selection for body size in Japanese quail, Coturnix coturnix japonica.

1. Body temperature, oxygen consumption, CO2 production and muscle protein degradation rate were measured in the three quail lines selected for body size, a random bred line (RR) and two lines selected for large (LL) or small (SS) body size. 2. The body temperature at 15 weeks of age was highest for small body size line and lowest for large body size line. 3. The body temperature, oxygen consumption and CO2 production of females were significantly higher than that of males. 4. The fractional degradation rate of muscle protein of SS, RR and LL lines were measured as 2.4, 1.6 and 1.2% per day in male, and 2.6, 1.7 and 1.4% per day in female.

Animals↗

PubMed1992

Circadian rhythm abnormalities of deep body temperature in depressive disorders.

We investigated circadian rhythms of body temperature in 62 inpatients with major depressive episodes, by monitoring the deep body temperature through the abdominal skin every two hours for a consecutive 48-h period. The data were analyzed by both the least-squares method and the maximum entropy spectral analysis (MEM) and were compared with those in 29 normal volunteers who apparently had a regular 24-h sleep-wake schedule. Circadian rhythm phase disturbances in the depressed patients were likely to be manifested in a phase normal or a phase delay pattern rather than in a phase advance pattern. The amplitude of body temperature was significantly smaller and the mesor was higher in the depressed patients than in the normal subjects. Analysis by MEM revealed that the periods of circadian rhythm of body temperature tended to be longer in the depressed patients than in the normal subjects, though there was no significant difference. The power spectral density by MEM was significantly lower, and there were significantly more ultradian rhythm components in the depressed patients than in the normal subjects. These findings suggest that the fundamental rhythm disturbance in depression may be a weakening of the coupling processes between internal pacemakers and an abnormal sensitivity to environmental information.

Adult↗

PubMed2006

Transgenic mice with a reduced core body temperature have an increased life span.

Reduction of core body temperature has been proposed to contribute to the increased life span and the antiaging effects conferred by calorie restriction (CR). Validation of this hypothesis has been difficult in homeotherms, primarily due to a lack of experimental models. We report that transgenic mice engineered to overexpress the uncoupling protein 2 in hypocretin neurons (Hcrt-UCP2) have elevated hypothalamic temperature. The effects of local temperature elevation on the central thermostat resulted in a 0.3 degrees to 0.5 degrees C reduction of the core body temperature. Fed ad libitum, Hcrt-UCP2 transgenic mice had the same caloric intake as their wild-type littermates but had increased energy efficiency and a greater median life span (12% increase in males; 20% increase in females). Thus, modest, sustained reduction of core body temperature prolonged life span independent of altered diet or CR.

Aging↗

PubMed1998

Thiamine deficiency-induced disruptions in the diurnal rhythm and regulation of body temperature in the rat.

In the present study, diurnal rhythm and regulation of body temperature were monitored during and several weeks following pyrithiamine-induced thiamine deficiency (PTD group, n=8) or pairfeeding (control group, n=9). A significant decline of core body temperature and a disruption of its diurnal rhythm were observed at varying stages of PTD treatment. Following thiamine administration and return to thiamine-fortified chow, body temperature continued to fall and several days transpired before body temperature and its diurnal rhythm were returned to normal. When exposed to warm and cold environments, no significant group differences were observed in either the maximum temperature change or the time elapsed to reach maximal temperature change. Histological examination revealed necrotic lesions in thalamus and mammillary body in the PTD group characteristic of Wernicke's encephalopathy. No significant damage was observed in the medial preoptic and suprachiasmatic nuclei, brain regions involved in the regulation of body temperature and circadian rhythm. These findings suggest that hypothermia and disruption of the diurnal rhythm of body temperature can be reversed by restoration of adequate thiamine levels and are related to biochemical and physiological disturbances rather than gross structural changes.

Animals↗

PubMed1999

Oral antibiotics reduce body temperature of healthy rabbits in a thermoneutral environment.

Nonabsorbable oral antibiotics, which reduce gut flora, decrease the daytime and night-time body temperatures of rats and mice. We investigated whether oral antibiotics would also lower the body temperature of healthy rabbits. Six rabbits received neomycin sulphate in their drinking water for ten days, and seven rabbits received a mixture of chloramphenicol and dihydroxystreptomycin for six days. Body temperatures, recorded using intra-abdominal radiotelemeters, decreased significantly, by 0.2-0.3 degree C, after three days of antibiotic treatment in both groups of rabbits. The drop in body temperature was transient; after six days body temperatures returned to pre-antibiotic levels. Antibiotic treatment had no effect on either the acrophase or the amplitude of the circadian rhythm in body temperature. Oral antibiotics therefore reduce body temperature of rabbits, without influencing the circadian rhythm in body temperature. Our results are consistent with the hypothesis that an agent arising from intestinal bacteria sustains an elevated body temperature in healthy animals.

Animals↗

PubMed2004

The hypothalamic-pituitary-thyroid axis and melatonin in humans: possible interactions in the control of body temperature.

OBJECTIVE: Melatonin plays a role in the regulation of biological rhythms, body temperature presents circadian variations with lower levels during nighttime, when melatonin levels are very high, and thyroid hormones influence shiver independent thermogenesis. We have investigated on possible interactions between the hypothalamic-pituitary-thyroid axis and melatonin in the control of body temperature in humans. METHODS: Peripheral blood samples for thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), free-thyroxine (FT4), melatonin levels determination and body temperature measurements were obtained every four hours for 24-hours starting at 0600 h in a controlled temperature and light-dark environment from ten healthy males, aged 38-65 (mean age +/-s.e. 57.4+/-3.03, mean body mass index +/-s.e. 25.5+/-0.75). We calculated fractional variation and correlation on single time point hormone serum levels and tested whether the time-qualified data series showed consistent pattern of circadian variation. RESULTS: A statistically significant difference was evidenced for the fractional variation of daytime TSH serum levels (0600 h-1000 h vs. 1000 h-1400 h, p=0.01, 1000 h-1400 h vs. 1400 h-1800 h, p=0.0001, 1400 h-1800 h vs. 1800 h-2200 h, p=0.001) and for the fractional variation of FT4 serum levels at 1800 h-2200 h vs. 2200 h-0200 h (p=0.02). FT4 serum levels correlated positively with TRH serum levels at 1000 h (r=0.67, P=0.03) and at 1400 h (r=0.63, p=0.04), negatively with TSH serum levels at 2200 h (r=-0.67, p=0.03), negatively with melatonin serum levels at 2200 h (r=-0.64, p=0.04) and at 0200 h (r=-0.73, p=0.01). TRH serum levels correlated positively with TSH serum levels at 0200 h (r=0.65, p=0.04) and at 0600 h (r=0.64, p=0.04). Body temperature correlated positively with FT4 serum levels at 1000 h (r=0.63, p=0.04) and negatively with melatonin serum levels at 0200 h (r=-0.64, p=0.04). A clear circadian rhythm was validated for body temperature (with acrophase in the morning) and melatonin, TRH and TSH secretion (with acrophase at night), while FT4 serum level changes presented ultradian periodicity (with acrophase in the morning). CONCLUSION: Changes of TSH serum levels are smaller and those of FT4 are greater at night, when melatonin levels are higher, so that the response of anterior pituitary to hypothalamic TRH and of thyroid to hypophyseal TSH may be influenced by the pineal hormone that may modulate the hypothalamic-pituitary-thyroid axis function and influence the circadian rhythm of body temperature.

Adult↗

PubMed1991

[Infrared tympanic thermography. A comparison of body temperature measured rectally and from the tympanic membrane].

Infrared tympanic thermography is a new method of measuring body temperature. We compared body temperature measured in the rectum and in the ear in 25 patients. The results reveal a difference of average +/- 0.3 degree C. We also measured the time used to perform the above procedures. We found that the preparation and completion procedures took on average two minutes and 50 seconds when the body temperature was measured in the rectum. Taking the temperature in the ear took on average 42 seconds. We found that this new method was an accurate and quick method to measure body temperature.

Body Temperature↗

PubMed1993

High dietary sodium chloride and body temperature in the domestic fowl and the glaucous-winged gull.

Arad and Skadhauge (1986) correlated plasma sodium to calcium ratio and body temperature in domestic fowl (Gallus domesticus) during increased dietary sodium chloride intake which increased plasma sodium concentration. During acclimation to high dietary NaCl, body temperature should increase in proportion to the increase in plasma sodium concentration, and body temperature should increase less in gulls than in chickens because salt gland secretion of NaCl by gulls should prevent elevation of plasma sodium concentration. Plasma osmolality, plasma sodium concentration, plasma concentrations of total calcium and ionized calcium, and body temperature and panting threshold were measured in domestic roosters and Glaucous-winged gulls before and after exposure to high NaCl diets. Gull body temperature (40.4 +/- 0.2 degrees C) increased significantly (P < 0.05) during salt acclimation. Rooster body temperature (41.0 +/- 0.2 degrees C) did not increase significantly. Plasma sodium concentration increased in gulls (5.4 +/- 0.5%, P < 0.01) and was correlated with body temperature (r = 0.497, P < 0.05); the 3.8 +/- 1.0% increase in plasma sodium concentration in roosters (P < 0.01) was not, suggesting that change in body temperature might be a response to the magnitude of increase in plasma sodium concentration. Plasma ionized calcium concentration increased by 12.9 +/- 4.6% (P < 0.01) in gulls and by 5.3 +/- 1.0% (P < 0.01) in roosters. Plasma sodium concentration was correlated with calcium ion concentration in both gulls (r = 0.635, P < 0.05) and roosters (r = 0.664, P < 0.05). In neither species were ratios of sodium to total calcium plasma concentration or sodium to ionized calcium concentration altered or related to body temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2006

Winter hibernation and body temperature fluctuation in the Japanese badger, Meles meles anakuma.

This study examined seasonal changes in body weight, hibernation period, and body temperature of the Japanese badger (Meles meles anakuma) from 1997 to 2001. Adult badgers showed seasonal changes in body weight. Between mid-December and February, badger activity almost ceased, as the animals remained in their setts most of the time. Adult male badgers were solitary hibernators; adult females hibernated either alone or with their cubs and/or yearlings. The total hibernation period of Japanese badgers ranged from 42 to 80 days, with a mean length of 60.1 days. Japanese badgers did not always spend the winters in the same sett, although they seldom changed setts during hibernation. I equipped a male cub with an intraperitoneally implanted data logger to record its body temperature between November and April, while the cub hibernated with its mother. Over the winter, the body weight of the cub decreased from 5.3 kg to 3.6 kg, a weight loss of 32.1%, and its body temperature ranged from 32.0 to 39.8 degrees C. The mean monthly body temperature was 35.1 degrees C in December, 34.8 degrees C in January, 35.9 degrees C in February, 37.1 degrees C in March, and 37.4 degrees C in April, so the monthly decrease in body temperature of this cub was not great. The results indicate that during hibernation, when body temperature is low, there is likely considerable economy of energy and a reduced demand for adipose reserves.

Animals↗

PubMed2002

Effect of a short photoperiod on circadian rhythms of body temperature and motor activity in old rats.

Circadian rhythms of body temperature and motor activity were documented in young and old rats (four 8-week-old and five 22-month-old male Wistars, implanted with telemetric probes and housed in a chronobiological facility) under two different photoperiod conditions. The animals were maintained in a light:dark (LD) cycle of 12 h each (LD 12:12) for 4 weeks and then exposed to a LD 6:18 cycle for 7 weeks to assess the effect of age on the desynchronization of the temporal structure of the rhythms. In old rats under LD 12:12, the power of the 24-h component and the circadian amplitude of body temperature and motor activity were markedly lower than in the young and both rhythms were phase-advanced. After the shift to LD 6:18, the circadian rhythmicity was maintained for both variables and the same phase delay (+5+/-1 h) was observed in both age groups, as was a gradual expansion of the patterns of both functions with the longer night. The photoperiod reduction (6 weeks under LD 6:18) did not modify the power of the 24-h component of body temperature and motor activity in old rats. In young rats, however, the power and amplitude of the 24-h component of motor activity rhythm fell to the levels of those in old rats, while the power of the 24-h component of body temperature rhythm and the amplitude did not change. Our data show that the circadian rhythm of motor activity, but not of body temperature, responds age dependently to a photoperiod reduction.

Aging↗