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Comparison of body temperatures taken at different sites and the reliability of axillary temperature in screening for fever.

This prospective study was carried out to compare temperatures taken at different sites and also to determine the reliability of axillary temperatures in screening for fever in healthy and febrile children under 10 years of age. The difference between the mean rectal and axillary temperatures was not significant in both healthy and febrile neonates (P > 0.05). However, in healthy and febrile children beyond the neonatal period the mean rectal temperature was significantly higher than the mean axillary temperature (P < 0.001), the difference between the mean axillary and oral temperatures was significant (P < 0.001) but there was no significant difference between the mean oral and mean rectal temperatures (P < 0.05). The mean axillary temperature stabilisation time was 3.8 minutes while the mean rectal and oral temperature stabilisation times were 1.6 minutes and 1.8 minutes respectively. The sensitivity of axillary temperatures in detecting fever was 98% among neonates but only 47% among children beyond the neonatal period. The specificity and positive predictive value were 100% each among both the neonates and children beyond the neonatal period. The negative predictive value was 98.7% among neonates while it was 64.4% amount the older children. It is concluded that unlike in older children axillary temperature in neonates correlates well with the core temperature and it is sensitive enough to detect fever. Axillary temperatures rather than rectal temperatures should be taken in neonates, while rectal or oral temperatures be taken in older children. When the axillary route is used, the thermometer should be left in place for at least 4 minutes.

Age Factors↗
PubMed2004

[Effect of pre-freezing temperature and lyophilizer shelf temperature on recovery of red blood cells after lyophilization].

To study effect of pre-freezing temperature and lyophilizer shelf temperature on recovery of human red blood cells after lyophilization and determine solidifying temperature of this lyophilization system, the protective solution composed of 7% DMSO, 40% polyvinylpyrrolidone (PVP) and isotonic buffer were adopted to lyophilize red blood cells at different pre-freezing temperatures or shelf temperatures. At first, fresh whole blood was centrifugated, washed and equilibrized to prepare concentrated red blood cells. Then concentrated red blood cells were mixed with the protective solution at 1:3 and pre-freezed at different temperature (-20, -35, -45, -80 or -196 degrees C) before lyophilization in lyophilizer. To study effect of shelf temperature on lyophilization of red blood cells, red blood cells were lyophilized at different shelf temperature after pre-freeze at -80 degrees C. After lyophilization, the samples were quickly rehydrated by 37 degrees C rehydration solution. The results showed the recovery rate of red blood cells and hemoglobin after pre-freeze at different temperature and lyophilization were > 85% and > 75%, there was not significant difference among these groups, but the concentration of free hemoglobin in -196 degrees C group was significantly higher than that in other groups (P < 0.01). With decreasing of shelf temperature, the lyophilizing time was also prolonged. When shelf temperature was > or = -25 degrees C, samples were not fully lyophilized; when shelf temperature was < or = -30 degrees C, the recovery rate of red blood cells and hemoglobin after lyophilization and rehydration were above 90%; after washed to isotonic state, the recovery rate of hemoglobin of the four groups was similar to each other. In conclusion, only when pre-freezing temperature is between -20 and -80 degrees C and the lyophilizer shelf temperature is < or = -30 degrees C, the effect of lyophilization is better, but the effect of excessively low pre-freezing temperature may even be worse.

Blood Preservation↗
PubMed1990

[The evaluation of tracheal temperature to monitor core temperature in various operations].

Tracheal temperature was evaluated to monitor core temperature during cardiac, upper abdominal and lower abdominal operations. The tracheal temperature was measured by a thermistor attached to the intra-cuff of the tracheal tube. In cardiac surgery, there was a good correlation between tracheal temperature and forehead deep temperature (r = 0.93) before and after cardiopulmonary bypass, and also between tracheal temperature and the temperature of blood from the cardiopulmonary bypass (r = 1.00) during cardiopulmonary bypass. These results indicate that tracheal temperature accurately reflects carotid artery temperature. In upper abdominal operations, the tracheal temperature showed good correlations with forehead core, esophageal, bladder and rectal temperatures (r = 0.81-0.90). On the other hand, bladder and rectal temperatures were different from forehead deep (r = 0.43, 0.55) and tracheal temperatures in lower abdominal operations. These results suggest that the tracheal temperature is valuable to monitor core temperature.

Abdomen↗
PubMed1995

Temperature compensation and temperature entrainment of the chick pineal cell circadian clock.

We have used an in vitro model system of the circadian clock, dispersed chick pineal cells, to examine the effects of temperature on the circadian clock of a homeotherm. This preparation enabled us to isolate a circadian clock from in vivo homeostatic temperature regulation and expose cells to both constant temperatures and abrupt temperature changes. By manipulating the temperature of the pineal cells, we have demonstrated that (1) the circadian clock compensates its period for temperature changes over the range of 34-40 degrees C; Q10 = 0.83, a value within the range of Q10 values measured for poikilothermic circadian clocks; (2) temperature pulses (42 degrees C, 6 hr duration) shift the phase (advance and delay) of the circadian rhythm in a phase-dependent manner; and (3) a temperature cycle (18 hr at 37 degrees C, 6 hr at 42 degrees C) will entrain the circadian clock in vitro. This is the first demonstration of temperature entrainment of the circadian clock of a homeotherm in vitro. In addition we have found that temperature directly influences the synthesis and release of melatonin, the primary hormonal product of the pineal gland. The biosynthesis of melatonin is strongly temperature dependent with a Q10 > 11 when melatonin release is measured at ambient temperatures between 31 degrees C and 40 degrees C. In contrast, 6 hr 42 degrees C temperatures pulses acutely inhibit melatonin release in a manner similar to that seen previously with light pulses. These results demonstrate that a circadian clock from a homeothermic vertebrate is temperature compensated, yet temperature cycles can entrain the circadian melatonin rhythm. Thus, the chick pineal circadian oscillator has retained all the fundamental properties of circadian rhythms.

Acclimatization↗
PubMed2004

Axillary and thoracic skin temperatures poorly comparable to core body temperature circadian rhythm: results from 2 adult populations.

Data from 2 separate studies were used to examine the relationships of axillary or thoracic skin temperature to rectal temperature and to determine the phase relationships of the circadian rhythms of these temperatures. In study 1, axillary skin and rectal temperatures were recorded in 19 healthy women, 21 to 36 years of age. In study 2, thoracic skin and rectal temperatures were recorded in 74 healthy women, 39 to 59 years of age. In both studies, temperatures were recorded continuously for 24 h while subjects carried out normal activities. Axillary and thoracic probes were insulated purposely to prevent ambient effects. Cosinor analysis was employed to estimate circadian rhythm mesor, amplitude, and acrophase. In addition, correlations between temperatures at various measurement sites were calculated and agreement determined. The circadian timing of axillary and skin temperature did not closely approximate that of rectal temperature: the mean acrophase (clock time) for study 1 was 18:57 h for axillary temperature and 16:12 h for rectal; for study 2, it was 03:05 h for thoracic and 15:05 h for rectal. Across individual subjects, the correlations of axillary or thoracic temperatures with rectal temperatures were variable. Results do not support the use of either axillary or skin temperature as a substitute for rectal temperature in circadian rhythm research related to adult women.

Adult↗
PubMed1991

Influence of Water and Temperature Stress on the Temperature Dependence of the Reappearance of Variable Fluorescence following Illumination.

The temperature dependence of the rate and magnitude of the reappearance of photosystem II (PSII) variable fluorescence following illumination has been used to determine plant temperature optima. The present study was designed to determine the effect of a plant's environmental history on the thermal dependency of the reappearance of PSII variable fluorescence. In addition, this study further evaluated the usefulness of this fluorescence technique in identifying plant temperature optima. Laboratory and greenhouse grown potato (Solanum tuberosum L. cv "Norgold M") plants had a thermal kinetic window between 15 and 25 degrees C. The minimum apparent K(m) of NADH hydroxypyruvate reductase for NADH occurred at 20 degrees C. This temperature was also the temperature providing maximal reappearance of variable fluorescence. Soybean (Glycine max [L.] Merrill cv "Wayne") plants had a thermal kinetic window between 15 and 30 degrees C with a minimum apparent K(m) at 25 degrees C. Maximal reappearance of variable fluorescence was seen between 20 and 30 degrees C. To determine if increasing environmental temperatures increased the temperature optimum provided from the fluorescence response curves, potato and soybean leaves from irrigated and dryland field grown plants were evaluated. Although the absolute levels of PSII variable fluorescence declined with increasing thermal stress, the temperature optimum of the dryland plants did not increase with increased exposure to elevated temperatures. Because of variability in the daily period of high temperature stress in the field, studies were initiated with tobacco plants grown in controlled environment chambers. The reappearance of PSII variable fluorescence in tobacco (Nicotiana tabacum L. cv "Wisconsin 38") leaves that had experienced continuous leaf temperatures of 35 degrees C for 8 days had the same 20 degrees C optima as leaves from plants grown at room temperature. The results of this study suggest that the temperature optimum for the reappearance of variable fluorescence following illumination is not altered by the plant's previous exposure to variable environmental temperatures. These findings support the usefulness of this procedure for the rapid identification of a plant's temperature optimum.

Journal Article↗
PubMed1986

Temperature control in Lowicryl K4M and glycol methacrylate during polymerization: is there a low-temperature embedding method?

An apparatus for embedding tissues at resin temperatures down to 228 K is described. By placing thermocouples in the resin the temperature has been monitored during embedding at low temperature with glycol methacrylate (GMA) and Lowicryl K4M. Even in this apparatus with a liquid cooling bath the heat of polymerization is not dissipated and the resin temperature rises. This rise is directly proportional to the resin temperature at the onset of polymerization and is higher in Lowicryl K4M than GMA. The initial resin temperature also affects the time taken for polymerization. The time to the onset of the peak and its duration are both increased as the temperature is lowered. This effect is more pronounced with GMA than Lowicryl K4M and polymerization of GMA is inhibited at the lowest temperature used. When Lowicryl K4M, polymerized at low temperature, is warmed up to ambient a further exothermic reaction occurs, which causes the resin temperature to rise well above ambient. Both this temperature peak and that during polymerization are reduced, but not totally eliminated, by reducing the resin volume. Air-cooled systems are inefficient compared with the low-temperature apparatus used here and the resin temperature rise is consequently greater and, even with small resin volumes, it can be very high. It is therefore unlikely for published methods that the temperature specified has been maintained in the resin during polymerization. The implications of these findings are discussed in relation to enzyme and antigen survival. Recommendations include use of very small volumes of resin, refrigerated liquid-bath rather than air-cooled systems and contact with a heat sink when specimens are warmed up to ambient temperature. Examples of enzyme reaction, antigen survival and structural preservation obtained with the method are presented.

Acrylates↗
PubMed1997

Comparison of distal oesophageal temperature with "deep" and tracheal temperatures.

PURPOSE: To compare distal oesophageal (reference) temperature with "deep-sternal," "deep-forehead," and tracheal temperatures, establishing the accuracy and precision of each. METHODS: We studied 20 patients undergoing general anaesthesia for gynaecological surgery. Their lungs were mechanically ventilated with a circle system, at a fresh-gas flow rate of 6 L.min-1 Respiratory gases were not warmed or humidified. Tracheal temperatures were recorded from a Trachelon tube inserted approximately 21 cm. Deep-body temperatures were measured at the sternum and forehead using a Coretemp thermometer. The principle of the method is to null thermal flux through a cutaneous disk, thus obliterating thermal gradients between the sides of the disk, skin surface, and subcutaneous tissues. Distal oesophageal temperatures were measured from thermocouples incorporated into oesophageal stethoscopes. Tracheal and deep-tissue temperatures were compared with oesophageal temperature using regression and Bland and Altman analyses. RESULTS: Tracheal, sternal, and forehead temperatures correlated similarly with distal oesophageal temperature, correlation coefficients (r2) being 0.7 in each case. The offset (oesophageal temperature minus study site) was considerably larger for tracheal temperature (0.7 degree C) than for the other sites (0.2 degree C). However, the precision was only 0.3 degree C at each site. CONCLUSION: Our data suggest that tracheal temperatures may not be an adequate substitute for conventional core-temperature monitoring sites. In contrast, the accuracy and precision of deep-tissue temperature monitoring at the sternum and forehead was sufficient for clinical use.

Anesthesia, General↗
PubMed2006

Estimation of mean body temperature from mean skin and core temperature.

BACKGROUND: Mean body temperature (MBT) is the mass-weighted average temperature of body tissues. Core temperature is easy to measure, but direct measurement of peripheral tissue temperature is painful and risky and requires complex calculations. Alternatively MBT can be estimated from core and mean skin temperatures with a formula proposed by Burton in 1935: MBT = 0.64 x TCore + 0.36 x TSkin. This formula remains widely used, but has not been validated in the perioperative period and seems unlikely to remain accurate in dynamic perioperative conditions such as cardiopulmonary bypass. Therefore, the authors tested the hypothesis that MBT, as estimated with Burton's formula, poorly estimates measured MBT at a temperature range between 18 degrees and 36.5 degrees C. METHODS: The authors reevaluated four of their previously published studies in which core and mass-weighted mean peripheral tissue temperatures were measured in patients undergoing substantial thermal perturbations. Peripheral compartment temperatures were estimated using fourth-order regression and integration over volume from 18 intramuscular needle thermocouples, 9 skin temperatures, and "deep" hand and foot temperature. MBT was determined from mass-weighted average of core and peripheral tissue temperatures and estimated from core temperature and mean skin temperature (15 area-weighted sites) using Burton's formula. RESULTS: Nine hundred thirteen data pairs from 44 study subjects were included in the analysis. Measured MBT ranged from 18 degrees to 36.5 degrees C. There was a remarkably good relation between measured and estimated MBT: MBTmeasured = 0.94 x MBTestimated + 2.15, r = 0.98. Differences between the estimated and measured values averaged -0.09 degrees +/- 0.42 degrees C. CONCLUSIONS: The authors concluded that estimation of MBT from mean skin and core temperatures is generally accurate and precise.

Aged↗
PubMed2004

Temperature regulation in burying beetles (Nicrophorus spp.: Coleoptera: Silphidae): effects of body size, morphology and environmental temperature.

This study compares the thermoregulatory ability of three species of burying beetle (Coleoptera: Silphidae: Nicrophorus hybridus, Nicrophorus guttula and Nicrophorus investigator) that vary significantly in body size. It also explores possible mechanisms for temperature regulation in burying beetles, including physiological and behavioral thermoregulatory strategies, and the influence of environmental temperatures on body temperature and activity times. We measured beetle thoracic and abdominal temperatures before and after short (<5 s) flights, and thoracic temperature during sustained, tethered flights and following flight in the field. We calculated two measures of thermoregulatory ability: the slope of post-flight thoracic temperature against ambient air temperature and the slope of post-flight thoracic temperature against operative flight temperature. Thoracic temperatures following flight were significantly higher than abdominal temperatures, and the largest species, N. hybridus, was determined to be the better thermoregulator, with regression slopes closer to zero (0.315-0.370) than N. guttula (0.636-0.771) or N. investigator (0.575-0.610). We also examined the roles that insulation, wing loading, physiological heat transfer, basking and perceived environmental temperature play on temperature regulation and activity times in Nicrophorus: This study shows that body size, morphological features, such as wing loading and insulation, and perceived environmental temperatures affect thermoregulation and activity times in burying beetles.

Animals↗
PubMed2000

Effects of color temperature of fluorescent lamps on body temperature regulation in a moderately cold environment.

A study on the effects of different color temperatures of fluorescent lamps on skin and rectal temperatures in a moderately cold environment involving (i) changes in skin temperature of 7 male subjects exposed to an ambient temperature ranging from 28 degrees C to 18 degrees C (experiment I) and (ii) changes in skin and rectal temperatures and metabolic heat production of 11 male subjects exposed to ambient temperature of 15 degrees C for 90 min (Experiment II) was conducted. In Experiment I, the reduction of mean skin temperature from the control value was significantly greater under 3000 K than under 5000 K or 7500 K lighting. In Experiment II, the reductions in mean skin temperature and rectal temperature were respectively greater and smaller under 3000 K than those under 5000 K or 7500 K lighting. However, metabolic heat production was not affected by color temperature conditions. The relationships between morphological and physiological parameters revealed that no significant relation of rectal temperature to body surface area per unit body weight was found only under 3000 K. Furthermore, while the mean skin temperature was independent on the mean skinfold thickness under 3000 K, a significant negative correlation between the rectal and mean skin temperatures was observed. Therefore, body heat loss might be suppressed effectively by increasing the vasoconstrictor tone under a color temperature of 3000 K, and the body shell was dependent only on morphological factors under 5000 K and 7500 K lighting.

Adult↗
PubMed2000

Variation of axillary temperature and its correlation with oral temperature.

UNLABELLED: Unilateral axillary temperature is recorded in unconscious patients and children due to its easy approach. OBJECTIVE: To evaluate variation of axillary temperature on the two sides and its correlation with oral temperature. SUBJECTS: One hundred and 46 healthy men and women, aged 12 through 52 years. METHODS: Axillary temperature from both sides and oral temperature were recorded using digital electronic thermometer in supine position with due precautions. RESULTS: Difference in temperature on the two sides of axilla was found to vary by as much as 0 degree F to 3.4 degrees F. Therefore, the data was grouped into higher and lower temperature ranges. The difference between mean oral and mean higher axillary temperature was found to be 0.5 degree F +/- 0.6 degree F (r = 0.564) while that in comparison to mean lower axillary temperature was 1.0 degree F +/- 0.89 degree F (r = 0.64). The difference between mean oral and mean axillary temperature was 1.0 degree F +/- 0.80 degree F (r = 0.84). CONCLUSIONS: Based on our observations, it is found that an average of temperature of both sides of axilla represents the axillary temperature more accurately and to get the correct oral equivalent of axillary temperature one should add 1 degree F to the mean axillary temperature.

Adolescent↗
PubMed1984

Body temperature changes in dogs exposed to varying effective temperatures.

Adult male and female Beagle dogs (eight total) were exposed individually, in series, to each of 23 effective temperatures for a period of 2 hours or until rectal temperature increased 1.1 degrees C. Rectal temperature was measured to the nearest 0.1 degree C by thermistor probes in the pre-test condition (basal temperature) and at each 5-minute interval during the test conditions (effective temperatures between 21.1 degrees C and 34.7 degrees C). The frequency at which dogs displayed a 1.1 degree C rise in rectal temperature was related to the magnitude of the effective temperature. At an effective temperature of 32.6 degrees C or greater, 100% of the dogs displayed a 1.1 degree C rise in rectal temperature. Between an effective temperature of 29.3 degrees C and 31.4 degrees C, some animals displayed a 1.1 degree C rise while others did not. At an effective temperature of 28.4 degrees C or below no animals displayed a 1.1 degree C rise. The mean time necessary for a 1.1 degree C rise was negatively correlated (P less than 0.01) to the magnitude of the effective temperature. The minimum effective temperature necessary to increase rectal temperature by 1.1 degree C in male Beagles (29.6 +/- 1.0 degree C) was not significantly different from females (30.8 +/- 0.4 degrees C).

Animals↗
PubMed1997

The effect of body temperature on the hunting response of the middle finger skin temperature.

The relationship between body temperature and the hunting response (intermittent supply of warm blood to cold exposed extremities) was quantified for nine subjects by immersing one hand in 8 degree C water while their body was either warm, cool or comfortable. Core and skin temperatures were manipulated by exposing the subjects to different ambient temperatures (30, 22, or 15 degrees C), by adjusting their clothing insulation (moderate, light, or none), and by drinking beverages at different temperatures (43, 37 and 0 degrees C). The middle finger temperature (Tfi) response was recorded, together with ear canal (Tear), rectal (Tre), and mean skin temperature (Tsk). The induced mean Tear changes were -0.34 (0.08) and +0.29 (0.03) degrees C following consumption of the cold and hot beverage, respectively. Tsk ranged from 26.7 to 34.5 degrees C during the tests. In the warm environment after a hot drink, the initial finger temperature (T(fi,base)) was 35.3 (0.4) degrees C, the minimum finger temperature during immersion (T(fi,min)) was 11.3 (0.5) degrees C, and 2.6 (0.4) hunting waves occurred in the 30-min immersion period. In the neutral condition (thermoneutral room and beverage) T(fi,base) was 32.1 (1.0) degrees C, T(fi,min) was 9.6 (0.3) degrees C, and 1.6 (0.2) waves occurred. In the cold environment after a cold drink, these values were 19.3 (0.9) degrees C, 8.7 (0.2) degrees C, and 0.8 (0.2) waves, respectively. A colder body induced a decrease in the magnitude and frequency of the hunting response. The total heat transferred from the hand to the water, as estimated by the area under the middle finger temperature curve, was also dependent upon the induced increase or decrease in Tear and Tsk. We conclude that the characteristics of the hunting temperature response curve of the finger are in part determined by core temperature and Tsk. Both T(fi,min) and the maximal finger temperature during immersion were higher when the core temperature was elevated; Tsk seemed to be an important determinant of the onset time of the cold-induced vasodilation response.

Adult↗
PubMed1987

No dynamic effector responses to fast changes of core temperature at constant skin temperature.

Experiments in conscious goats were done to see whether heat production and respiratory evaporative heat loss show dynamic responses to changing core temperature at constant skin temperature. Core temperature was altered by external heat exchangers acting on blood temperature, while skin temperature was maintained constant by immersing the animals up to the neck in a rapidly circulating water bath. Core temperature was altered at various rates up to 0.9 degrees C/min. Step deviations of core temperature from control values were always followed by a positive time derivative of effector response, but never by a negative time derivative during sustained displacement of core temperature. Ramp experiments showed that the slopes at which heat production or heat loss rose with core temperature deviating from its control level grew smaller at higher rates of change of core temperature. It is concluded that neither heat production nor respiratory evaporative heat loss respond to the rate of change of core temperature. At constant skin temperature, thermoregulatory effector responses appear to be proportional to the degree to which core temperature deviates from its set level.

Animals↗
PubMed2004

Relationships between the circadian rhythms of finger temperature, core temperature, sleep latency, and subjective sleepiness.

Skin temperature circadian rhythms have been explored relatively recently. It has been suggested that distal and proximal skin temperature changes play a role in the regulation of the core temperature circadian rhythm and sleepiness. The authors investigated the circadian finger and core temperature rhythms in conjunction with the circadian rhythms of subjective and objective sleepiness. Fourteen healthy, young, good sleepers participated in a modified constant-routine procedure in which palmar finger temperature, rectal temperature, subjective sleepiness, and objective sleep latency were measured half-hourly across a 48-h period of enforced wakeful bed rest. Individual curves were adjusted to the group mean temperature minimum time of 0500 h and averaged to create the 4 mean curves. The 5 possible cross-correlation curves between these 4 measures were calculated for half-hourly phase lags from 12 h before to 12 h after the group mean core temperature minimum time. Maximum cross-correlations for each curve suggested that finger temperature preceded core temperature by 3 h (r = -0.22), and subjective sleepiness followed core temperature by 0.5 h (r = -0.33) and objective sleepiness by 2 h (r = 0.29). Although these data are correlational, they are consistent with the notion that finger temperature changes drive core temperature changes, which determine changes of subjective and objective sleepiness.

Adult↗
PubMed1995

Differential effects of growth temperature on ice nuclei active at different temperatures that are produced by cells of Pseudomonas syringae.

The temperature at which ice-nucleating bacteria are grown causes differences of 100- to 10,000-fold in the fraction of cells that nucleate ice at a given temperature (ice nucleation frequency). Ice nucleation frequencies of cells of Pseudomonas syringae grown at temperatures that ranged from 9 to 33 degrees C were examined in order to more accurately characterize physiological effects on ice nuclei active at temperatures of from about -2 to -10 degrees C, the temperature range for this phenotype. Large differences in ice nucleation frequency occurred at all but the lowest assay temperatures in cells of P. syringae grown in the temperature range of 15 to 33 degrees C. These differences in ice nucleation frequency may be attributed, at least in part, to post-translational factors. Because other studies have indicated that ice nuclei active at the lowest assay temperatures may reflect the amount of ice nucleation protein produced, while higher nucleation temperatures reflect aggregates of this ice nucleation protein, data was normalized to the frequency of ice nuclei active at the lowest ice nucleation temperatures (which also correspond to the most abundant nuclei). This was done in order to develop a baseline of comparison for cells grown at different temperatures that more clearly shows possible post-translational effects such as aggregation of the nucleation protein. After this normalization was performed, and in contrast to the results noted above, the number of ice nuclei in cells grown at 9, 15, and 20 degrees C that were active at different assay temperatures was very similar. Differences in ice nucleation frequency that occurred over all assay temperatures in cells grown between 9 and 20 degrees C may be attributed to differences in the total number of nuclei present in the population of cells. The large effects of growth temperature on nucleation frequency have important implications for estimating numbers of ice nucleating bacteria in environmental samples by determining the number of bacterial ice nuclei in such samples.

Bacterial Outer Membrane Proteins↗
PubMed1984

Age-related changes in amino acid pool sizes in the adult silkmoth, Bombyx mori, reared at low and high temperature; a biochemical examination of the rate-of-living theory and urea accumulation when reared at high temperature.

To examine the rate-of-living theory, age-related changes in amino acid pool sizes were investigated in the adult silkmoth, Bombyx mori, reared at low and high temperature. At either temperature concentrations of free amino acids contained in silkmoths revealed a great sexual difference. Those in females were generally much higher than in males and the former changed much more dynamically than the latter. Major amino acids or ninhydrin-positive compounds inclusive of some essential amino acids such as Leu, Ile, Val, Thr, Arg, Phe, Met, Ala, Tyr, Gln, Aspn , Lan , Cysta , GABA and PEA accumulated in 4 degrees C-moths. However, the levels of these amino changed irregularly with advanced age. Inhibition of protein synthesis may occur generally at low temperature, while protein degradation may be promoted at high temperature. High concentrations of MSO and Tau in the moths reared at high temperature than in the normal moths suggested also catabolism of amino acids proceeding together with protein degradation at high temperature. Amino acid metabolism seems to be complicated under various temperature conditions. When reared at the optimal temperature of 25 degrees C, urea is not present in the body of the silkmoth except for a slight amount in the secreted meconium. In silkmoths reared at the higher temperature of 35 degrees C, however, an extraordinary accumulation of urea occurs accompanied by a reduction in lifespan by one half. Undoubtedly, urea is produced in this terrestrial insect, although the accumulation mechanism is not clear: in silkmoths reared at various temperatures, arginase is found, but urease is not detected. Arginase activity was found to be higher in male moths than in female moths regardless of the rearing temperature. High temperature rearing also did not induce activity and female activity never exceeded that in males at either 25 degrees C or 35 degrees C rearing. Protein degradation accelerated by rearing at high temperatures may result in increased amounts of free arginine, which could cause the active production of urea. This possibility would be a counter-argument to the rate of living theory relating to longevity and temperature. However, at least the above facts signify that an extrinsic factor influences the longevity of an animal by altering its intrinsic aging process.

Aging↗