Variation In Body Temperature Research Articles

Development of the hypothalamus and pituitary in platypus (Ornithorhynchus anatinus) and short‐beaked echidna (Tachyglossus aculeatus)

The living monotremes (platypus and echidnas) are distinguished by the development of their young in a leathery-shelled egg, a low and variable body temperature and a primitive teat-less mammary gland. Their young are hatched in an immature state and must deal with the external environment, with all its challenges of hypothermia and stress, as well as sourcing nutrients from the maternal mammary gland. The Hill and Hubrecht embryological collections have been used to follow the structural development of the monotreme hypothalamus and its connections with the pituitary gland both in the period leading up to hatching and during the lactational phase of development, and to relate this structural maturation to behavioural development. In the incubation phase, development of the hypothalamus proceeds from closure of the anterior neuropore to formation of the lateral hypothalamic zone and putative medial forebrain bundle. Some medial zone hypothalamic nuclei are emerging at the time of hatching, but these are poorly differentiated and periventricular zone nuclei do not appear until the first week of post-hatching life. Differentiation of the pituitary is also incomplete at hatching, epithelial cords do not develop in the pars anterior until the first week, and the hypothalamo-neurohypophyseal tract does not appear until the second week of post-hatching life. In many respects, the structure of the hypothalamus and pituitary of the newly hatched monotreme is similar to that seen in newborn marsupials, suggesting that both groups rely solely on lateral hypothalamic zone nuclei for whatever homeostatic mechanisms they are capable of at birth/hatching.

Thermal ecology of Microlophus occipitalis (Sauria: Tropiduridae) in the Plain Dry Forest of Tumbes, Peru

The thermal ecology of Microlophus occipitalis Peters 1871 in the plain dry forests of Tumbes (northewestern Peru) was studied. Mean body temperature was 36.1 ± 1.8 ºC, similar to body temperatures exposed by Microlophus peruvianus in northern Peru. There were no differences between body temperature and degree of thermoregulation of males and females, due to a possible association to their social structure and microhabitat use. Air and substrate temperature affects the body temperature of Microlophus occipitalis, where air temperature accounts for a significant proportion of body temperature variation. We suggest more detailed studies on this lizard species, especially under climate change scenarios in northwestern Peru.

Variation in body temperature is related to ambient temperature but not experimental manipulation of insulation in two small endotherms with different thermoregulatory patterns

AbstractMaintaining a high and constant body temperature (T b) is thought to enhance performance in endotherms, but such a thermoregulatory pattern is energetically expensive. Thus, some variation in T b is probably universal among endotherms, and several recent attempts have been made to generalize the factors that should cause this variation. Two factors that may be closely tied to the thermoregulatory pattern expressed are the cost of thermoregulation and food availability. To test these predictions, we measured T b of eastern rock elephant shrews (Elephantulus myurus; a traditionally defined heterotherm) and Namaqua rock mice (Micaelamys namaquensis; a homeotherm) in the field and under semi‐natural conditions after experimentally reducing insulation by shaving a patch of dorsal fur. After accounting for ambient temperature (T a), there was no significant difference in the level of variation in T b between shaven and unshaven elephant shrews. In rock mice, the increase in heat loss paradoxically led to decreased variation in T b in the field, but no effect was evident in captivity. Furthermore, as predicted, both species displayed significantly less variation in T b under semi‐natural conditions when given food ad libitum and predation risk involved with obtaining that food was low. Our results show that small mammals, both homeothermic and heterothermic, are capable of altering their thermoregulatory patterns in response to ecological conditions (e.g. rapid changes in food availability). However, increasing the cost of thermoregulation, at least as it was done in this experiment, does not appear to affect the expression of T b as strongly as does T a.

Hydration state of bats may explain frequency of arousals from torpor

Bats hibernate to cope with unfavorable conditions, such as low ambient temperature (Ta) and low food availability. However, hibernation is frequently interrupted by arousals that are believed to be responsible for more than 85% of the animal's winter energy expenditure. To date, arousal in bats has been associated with either variation in body temperature (Tb), in Ta, or in both. Considering either Tb or Ta to be the cue to arousal has led to a single testable prediction, i.e. that torpor bout length (TBL) is negatively correlated with Ta and Tb. It is now known that Ta and Tb are both correlated with TBL, but correlations alone cannot establish a causal link between arousal and Tb or Ta. Since hydration state too has been implicated in arousal from hibernation, we hypothesized that water loss while hibernating creates the need to restore body water and electrolyte balance, and bats arouse to drink. We measured the TBL of bats (Pipistrellus kuhlii) kept in different conditions of humidity, but at the same Ta. We found an inverse relationship between TBL and total evaporative water loss that is independent of metabolic rate, thus supporting the hypothesis that hydration state is a cue to arousal in bats.

Intraoperative lactate levels and postoperative complications of pediatric cardiac surgery

Correlate arterial lactate levels during the intraoperative period of children undergoing cardiac surgery and the occurrence of complications in the postoperative period. Arterial lactate levels can indicate hypoperfusion states, serving as prognostic markers of morbidity and mortality in this population. Anesthesia for cardiac pediatric surgery is frequently performed on patients with serious abnormal physiological conditions. During the intraoperative period, there are significant variations of blood volume, body temperature, plasma composition, and tissue blood flow, as well as the activation of inflammation, with important pathophysiological consequences. Chart data relating to the procedures and perioperative conditions of the patients were collected on a standardized form. Comparisons of arterial lactate values at the end of the intraoperative period of the patients that presented, or not, with postoperative complications and frequencies related to perioperative conditions were established by odds ratio and nonparametric univariate analysis. After surgeries without cardiopulmonary bypass (CPB), higher levels of arterial lactate upon ICU admission were observed in patients who had renal complications (2.96 vs 1.31 mm) and those who died (2.93 vs 1.40 mm). For surgeries with CPB, the same association was observed for cardiovascular (2.90 mm × 2.06 mm), renal (3.34 vs 2.33 mm), respiratory (2.98 vs 2.12 mm) and hematological complications (2.99 vs 1.95 mm), and death (3.38 vs 2.40 mm). Elevated intraoperative arterial lactate levels are associated with a higher morbidity and mortality in low- and medium-risk procedures, with or without CPB, in pediatric cardiac surgery.

Tub Bathing Improves Thermoregulation of the Late Preterm Infant

To compare body temperature of the late preterm infant after 24 hours of life at three time points before and after immersion tub bathing or sponge bathing. We hypothesized that late preterm infants achieve significantly improved thermoregulation when bathed by immersion tub bath compared to traditional sponge bathing. This study was a randomized controlled trial. A large metropolitan teaching hospital in the northeastern United States. Late preterm infants (100) born between 35 and 36 6/7 weeks gestation, bathed in the well-baby nursery of a 30-bed mother/baby unit. Infant participants were identified and informed consent was obtained from the parent. Infants were randomized into two groups: 50 bathed by sponge and 50 bathed by immersion tub. Infant body temperature was measured at three time points: 10 minutes prior to bathing, 10 minutes following bathing, and 30 minutes following bathing. Infants who were tub bathed experienced significantly less variability in body temperature and overall were warmer 10 minutes and 30 minutes following the bath compared to infants who were sponge bathed (p = .024). The study findings support the hypothesis that late preterm infants who are tub bathed experience significantly less body temperature variability and an overall higher body temperature following the bathing procedure.

Performance Validation of a Modified Magnetic Resonance Imaging–Compatible Temperature Probe in Children

During magnetic resonance imaging (MRI), children are at risk for body temperature variations. The cold MRI environment that preserves the MRI magnet can cause serious hypothermia. On the other hand, hyperthermia may also develop because of radiofrequency-induced heating of the tissues, particularly in prolonged examinations. Because of a lack of MRI-compatible core temperature probes, temperature assessment is unreliable, and specific absorption rate-related patient heat gain must be calculated to determine the allowable scan duration. We compared an MRI-compatible temperature probe and a modification thereof to a standard esophageal core body temperature probe in children. Children undergoing general anesthesia were recruited, each patient serving as his/her own control. Core body temperature was measured using 3 different devices: (1) a fiberoptic MRI-compatible skin surface temperature probe (MRI-skin) located on the child's skin surface; (2) a fiberoptic MRI-compatible temperature probe modified with a single-use sleeve at the tip (MRI-core), located in the nasopharynx; and (3) a standard temperature monitor (STRD) located in the esophagus or nasopharynx. The Bland-Altman method was used for statistical analysis. We enrolled 60 children aged 7.8 ± 6 years (mean ± SD) weighing 32.4 (±26.4) kg. The estimated difference between the STRD and MRI-core measurements of core temperature was 0.06°C (confidence interval [CI]: -0.02, 0.15), and between the STRD and the MRI-skin 1.19°C (CI: 0.97, 1.41). According to the Bland-Altman analysis, the 95% limits of agreement ranged from -0.9 to 3.4 and from -1.3 to 1.2 between the STRD and the MRI-skin probe and the MRI-core probe, respectively. Our results show good agreement between standard esophageal measurements of core temperature and core temperature measured using a modified MRI-core probe during general anesthesia in a general surgical pediatric population. The ability to accurately assess core temperature in the MRI suite may safely allow longer scan times and therefore reduce repeat anesthetic exposure, improve patient safety, and enhance the quality of care in children.

Body temperature evaluation during induced pneumoperitoneum with CO2: an experimental study in pigs

In prolonged laparoscopic procedures, hypothermia is frequently observed. The possible influence of the vasodilating action of CO(2), due to its increased levels in the blood during the laparoscopic procedures, has yet to be studied. The objective of this study was, therefore, to evaluate body temperature patterns in pigs subjected to pneumoperitoneum with CO(2). Thirty male pigs were allocated into three groups of ten animals each: group I, anesthetic procedure and abdominal puncture only; group II, the same as for group I and insufflation with CO(2); and group III, the same as for group I and insufflation with medical grade compressed air. After anesthetic induction and surgical preparation, rectal and esophageal temperatures were measured every 10 min. Blood was collected during the experiment for the gasometric measurement of pCO(2). Animals were insufflated with no gas loss and were kept anesthetized for 180 min. For statistical analysis, Friedman and Kruskal-Wallis tests were used at a level of significance of 95% (P < 0.05). Animals in groups I and II (P = 0.000) had a statistically significant drop in both esophageal and rectal temperatures during the experiment, but not animals in group III. However, when the groups were compared among themselves, no statistically significant differences were found at any of the times measured. A statistically significant drop in pCO(2) levels was observed for groups I and III, but not for animals in groups II. The use of CO(2) did not significantly affect body temperature variation in pigs subjected to pneumoperitoneum. However, CO(2) produced a temperature drop pattern different than that of compressed air, indicating that CO(2) may lead to thermoregulatory changes and influence the peripheral temperature drop.

孵化温度对赤链蛇胚胎代谢和幼体行为的影响

We collected adult females of Dinodon rufozonatum(Colubridae) from a population in Zhejiang,Southeast China,to study the effects of incubation temperature on embryonic metabolism and hatchling behavior.We incubated eggs at there constant temperatures ranging from 24 ℃ to 30 ℃,and weighed containers and eggs at 5-day intervals.The duration of incubation,measured as the number of days to pipping,was recorded for each egg.Eggs were measured for changes in size and embryonic metabolism at 5-day intervals.The response to chemical cues,respiration metabolism and sexual phenotype were determined for each hatchling.Because physiological and behavioral performances are highly sensitive to variation in body temperature in reptiles,we conducted all trials at the body temperature of 28 ℃.This was achieved by placing hatchlings in an incubator at the test temperature for approximately 1 h prior to testing.We presented a cotton-tipped applicator soaked with cologne water to the lip of hatchlings and recorded tongue flicks for 1 min.Tongue flicking was measured because many reptiles flick their tongues frequently to detect both predators and prey and to gather information about other members of their own species.The behavioral character is therefore a potentially important indicator of fitness. Incubation temperature affected incubation length,mass gain and energy consumption of eggs during incubation and locomotor performance of hatchlings,but not the rate of embryonic metabolism,hatchling success and tongue flicking.Incubation length decreased exponentially as incubation temperature increased.All eggs gained mass during incubation due to absorption of water.Incubation temperature affected water exchanges between eggs and their surroundings,thereby affecting the hydric conditions inside the egg.Eggs incubated at 24 ℃ gained more mass and comsumed more energy to hatch than did eggs at 30 ℃,but eggs incubated at these two temperatures did not differ from eggs incubated at 27 ℃ in mass gain and energy consumption during incubation.Swimming speed was greatest in hatchlings incubated at 27 ℃ and lowest in hatchling incubated at 24 ℃,with hatchlings incubated at 30 ℃ in between.Hatchlings incubated at the three temperatures did not differ from each other in tongue flicking. The carbon dioxide breathed out by eggs decreased as incubation temperature increased.The amount of energy consumed by embryos developing at 24,27 and 30 ℃ during incubation was 6.63,4.42 and 3.42 J,respectively.This result better explains why hatchlings incubated at lower temperatures are larger in snout-vent length and heavier than those incubated at higher temperatures.Though the rate of embryonic metabolism did not differ among three temperature treatments,incubation length was longer at lower than at higher temperatures so that embryons at lower temperatures needed more energy to complete development.This explains why hatchlings from eggs incubated at lower temperatures had more residual yolks than did those from higher incubation temperature. Our results reveal that incubating eggs at temperatures ranging from 24—30 ℃ does not have important effects on embryonic metabolism and hatchlings behavior in D.rufozonatum.This temperature range seems like temperature at habitat of D.rufozonatum.

孵化温度对双斑锦蛇初生幼体行为和呼吸代谢的影响

Elaphe bimaculata(Colubridae) is a small rat snake(60—80 cm) found in China.We collected adult E.bimaculata from a population in Jiangsu,Eastern China,to study the effect of incubation temperature on hatchlings′ metabolism and behavior.We incubated the eggs at their constant temperatures(24,27 and 30 ℃).All hatchlings were used to evaluate the response to chemical cues,respiration metabolism and sex determination.Because physiological and behavioral performances are highly sensitive to variation in body temperature in reptiles,we conducted all trials at the body temperature of 28 ℃.This was achieved by placing hatchlings in an incubator at the test temperature for approximately 1h prior to the test.We presented a cotton-tipped applicator soaked with cologne water to the lip of hatchlings and recorded tongue flicks for 1 min.Tongue flicking was measured because many reptiles flick their tongues frequently to detect both predators and prey and to gather information about other members of their own species.This behavioral character is therefore a potentially important indicator of fitness. Selected body temperature was examined in a 100 cm × 60 cm × 60 cm terrarium covered with sand,sward and pieces of clay tiles.The terrarium was placed in constant temperature rooms where the temperature was set at 24 ℃.One light bulb(200 W) suspended above one end created a thermal gradient ranging from room temperature to 50 ℃ for 12h daily,and lights were switched on at 07:00 h.Snakes were moved from the cool side into the terrarium at 10:00 h and,24 h later,they were measured for body temperature(cloacal temperature,Tb) at 13:00 h using a UT-325 electronic thermometer(made in Taiwan) individually,which had an external thermal probe and was previously calibrated with a standard thermometer.Great care was taken to avoid heat transfer occurring between hands and the measuring snake.Hereafter,we continuously measured the temperature of hatchling snakes for three days. Our results reveal that there were no significant differences in the effects of incubation temperature(24—30 ℃) on hatchlings′ tongue flicks,selected body temperature,respiration metabolism and the initial feeding in E.bimaculata.The amount of carbon dioxide was decreased with the increase of age from nativity to residual yolk,and the amount of carbon dioxide decreased to minimum value when the hatchlings′ residual yolk was absolutely exhausted.The amount of carbon dioxide breathed out by hatchlings incubated at 24,27 and 30 ℃ was 10.58、12.06 and 10.88 μL/min respectively.Influences of incubation temperatures on hatchling initial feeding was negligible;the weight of preys were 4.92,4.34 and 3.60 g and the proportion of predation was 46.2%,56.3% and 40% by hatchlings incubated at 24,27 and 30 ℃ respectively.Our results reveal that the effects of incubation temperature(24—30 ℃) on hatchlings behavior and feeding are not significant in E.bimaculata.E.bimaculata fit to live in this temperature range.

Body temperature variation of South African antelopes in two climatically contrasting environments

To understand the adaptive capacity of a species in response to rapid habitat destruction and climate change, we investigated variation in body temperature (Tb) of three species of antelope, namely eland, blue wildebeest and impala, using abdominally-implanted temperature data loggers. The study was conducted at two climatically contrasting environments in South Africa, one with a less seasonal and mild winter (Mapungubwe National Park) and the other with a more seasonal, long and cold winter (Asante Sana Game Reserve). Since the habitat with long and cold winters would be suboptimal for these African antelopes, which evolved in less seasonal and hot environments, antelopes in Asante Sana were expected to exhibit a larger amplitude in Tb and a lower minimum body temperature (MinTb) during winter to reduce Tb and the ambient temperature (Tb−Ta) gradient to save energy. In both eland and impala, 24-h body temperature amplitude did not differ between the study sites, regardless of season. Conversely, wildebeest in Mapungubwe showed a higher variability in the 24-h amplitude of body temperature and also a lower MinTb during winter and spring than the wildebeest in Asante Sana. This variation in Tb among Mapungubwe wildebeest was influenced by both the amplitude of ambient temperature (positive) and cumulative rainfall (negative), which was not the case for wildebeest in Asante Sana. We propose that the low MinTb of wildebeest in Mapungubwe was the result of nutritional stress during winter and spring; an evident response even during a year of average rainfall. Therefore, these wildebeest apparently live in a physiologically stressful environment. With the predicted increase in the frequency and intensity of drought periods in southern Africa, wildebeest and other grazers, will likely experience greater nutritional stress in the future.

Glicemia perioperatória e complicações pós-operatórias em cirurgia cardíaca pediátrica

Anesthesia for pediatric cardiac surgery is systematically performed in severely ill patients under abnormal physiological conditions. In the intraoperative period, there are significant variations in blood volume, body temperature, plasma composition, and tissue blood flow, in addition to activation of inflammation, with important consequences. Serial measurements of blood glucose levels can indicate states of exacerbation of the neuroendocrine-metabolic response to trauma, serving as prognostic markers of morbidity in that population. To correlate perioperative blood glucose levels of children undergoing cardiac surgery with the occurrence of postoperative complications, and to compare intraoperative blood glucose levels according to perioperative conditions. Information regarding the surgical/anesthetic procedure and perioperative conditions of patients was collected from the medical records. The mean perioperative blood glucose levels in the groups of patients with and without postoperative complications and the frequencies of perioperative conditions were compared by use of odds ratio and non-parametric univariate analyses. Higher intraoperative blood glucose levels were observed in individuals who had postoperative complications. Prematurity, age group, type of anesthesia, and character of the procedure did not influence the mean intraoperative blood glucose level. The use of extracorporeal circulation (ECC) was associated with higher blood glucose levels during surgery. In procedures with ECC, higher blood glucose levels were observed in individuals who had infectious and cardiovascular complications. In surgeries without ECC, that association was observed with infectious and hematological complications. Higher intraoperative blood glucose levels are associated with higher morbidity in the postoperative period of pediatric cardiac surgery.

Does size matter? Comparison of body temperature and activity of free-living Arabian oryx (Oryx leucoryx) and the smaller Arabian sand gazelle (Gazella subgutturosa marica) in the Saudi desert

Heterothermy, a variability in body temperature beyond the normal limits of homeothermy, is widely viewed as a key adaptation of arid-adapted ungulates. However, desert ungulates with a small body mass, i.e. a relatively large surface area-to-volume ratio and a small thermal inertia, are theoretically less likely to employ adaptive heterothermy than are larger ungulates. We measured body temperature and activity patterns, using implanted data loggers, in free-ranging Arabian oryx (Oryx leucoryx, ±70 kg) and the smaller Arabian sand gazelle (Gazella subgutturosa marica, ±15 kg) inhabiting the same Arabian desert environment, at the same time. Compared to oryx, sand gazelle had higher mean daily body temperatures (F(1,6) = 47.3, P = 0.0005), higher minimum daily body temperatures (F(1,6) = 42.6, P = 0.0006) and higher maximum daily body temperatures (F(1,6) = 11.0, P = 0.02). Despite these differences, both species responded similarly to changes in environmental conditions. As predicted for adaptive heterothermy, maximum daily body temperature increased (F(1,6) = 84.0, P < 0.0001), minimum daily body temperature decreased (F(1,6) = 92.2, P < 0.0001), and daily body temperature amplitude increased (F(1,6) = 97.6, P < 0.0001) as conditions got progressively hotter and drier. There were no species differences in activity levels, however, both gazelle and oryx showed a biphasic or crepuscular rhythm during the warm wet season but shifted to a more nocturnal rhythm during the hot dry season. Activity was attenuated during the heat of the day at times when both species selected cool microclimates. These two species of Arabian ungulates employ heterothermy, cathemerality and shade seeking very similarly to survive the extreme, arid conditions of Arabian deserts, despite their size difference.

Effect of Altered Core Body Temperature on Glottal Closing Force

A basic function of the larynx is to provide sphincteric protection of the lower airway, initiated by a brain stem-mediated glottal closure reflex. Glottal closing force is defined as the measured pressure generated between the vocal folds during glottal closure. One of the factors thought to affect the glottal closure reflex is a variation in core body temperature. Four adult male Yorkshire pigs were used in this study. The subjects were studied under control conditions (37 degreesC), hyperthermic conditions (38 degrees C to 41 degrees C), and hypothermic conditions (36 degrees C to 34 degrees C). We demonstrated that the glottal closing force increased significantly with an increase in core body temperature and also decreased significantly with decreased core body temperature. These results are supported by neurophysiological changes demonstrated by other studies in pups and adult dogs in response to altered core body temperatures. The mechanism for these responses is thought to reside centrally, rather than in the peripheral nervous system. We hope that a better understanding of these aspects of glottal closure will alter the care of many patients with postanesthesia hypothermia and many sedated inmates and will also further enhance preventive measures needed to decrease the incidence of sudden infant death syndrome in overheated or febrile infants.

Variability of body temperature in dialysis patients

Variability of body temperature in dialysis patients

Does use of the torpor cut-off method to analyze variation in body temperature cause more problems than it solves?

The torpor cut-off method is widely used in papers on endothermic heterothermy to describe patterns in body temperature. However, this method has several theoretical and logistical limitations, some already recognized but others not, that may hinder our understanding of heterothermy in endotherms. Here we discuss these limitations and their implications and argue that new analytical techniques should be developed and used in the study of endothermic heterothermy.

Circadian variations in body temperature during dialysis

Thermal changes during dialysis strongly influence intra-dialytic hemodynamics. The mechanisms behind the increase in body temperature during hemodialysis (HD) are still not completely understood. The objective of this retrospective observational cohort study is to assess the effect of circadian variation on body temperature changes during HD by comparing results in patients treated on different treatment shifts. Data from the Renal Research Institute, New York, clinical database encompassing patients treated in six states in the USA were used. Data from January and August 2008 were used for analysis. Body temperature changes during HD were categorized by dialysis shifts. Patients with morning shifts (n = 1064), afternoon shifts (n = 730) and evening shifts (n = 210) were compared. Pre-dialysis body temperatures were significantly different among the different shifts [morning, 36.41 (95% confidence interval: 36.39-36.43°C), afternoon, 36.47 (36.45-36.49°C), evening, 36.67 (36.64-36.70°C), P < 0.001]. In August, but not in January, intra-dialytic increases in body temperature were significantly different between patients treated during morning [0.07 (0.058-0.082°C)], afternoon [0.03 (0.016-0.044°C)] and evening shifts [-0.01 (-0.032 to 0.012°C); P < 0.001 analysis of variance], although in January, treatment shift was a significant predictor of the intra-dialytic increase in body temperature. The intra-dialytic change in body temperature was related not only to the pre-dialysis body temperature (r(2) = 0.31; P < 0.001) but also to microbiological dialysate quality, treatment time and dialysate temperature. The intra-dialytic change in blood pressure (BP) was significantly related to changes in intra-dialytic body temperature irrespective of the study month. Both pre-dialytic body temperature as well as changes in body temperature are significantly related to the timing of the dialysis shifts, in phase with the circadian body temperature rhythm. Due to the relationship between body temperature changes and changes in intra-dialytic BP, these findings might be of additional relevance in the pathogenesis of intra-dialytic hypotension.

온실에서 방울토마토 수확작업시 작업자의 생리학적 및 생체역학적 반응 측정

Physiological signals such as body temperature, heart rate, blood pressure and heart rate variability and biomechanical workload for stress analysis were investigated during the cherry tomato harvesting work in a greenhouse. The skin temperatures raised <TEX>$0.05^{\circ}C$</TEX>/min, <TEX>$0.03^{\circ}C$</TEX>/ min, and <TEX>$0.08^{\circ}C$</TEX>/min in standing, stooping and squatting postures, respectively. Breath rate significantly increased from 18 to 28 breaths/min during the cherry tomato harvesting work. As the heart rate during the work ranged from about 72 to 110 beats/min (bpm), the cherry tomato harvesting work appeared to be a light intensity task of less than 110 bpm. The worker's average energy consumption rate in three positions during 43 min working time was 65.74 kcal (91 kcal/h in 70 kg). This was a light intensity of work, compared to 75 kcal/h in 70 kg of basic metabolic energy consumption rate of a worker with 70 kg weight; The maximum shear force on the disk (L5/ S1) due to static workload in the cherry tomato harvesting work was 446 N in the stooping posture, 321 N in the squatting posture and 287 N in the standing posture. Acute stress index expressed with the heart rate variability, increased parasympathetic activation up to about 70 while workers were doing most agricultural work in this study. This study provided a system to measure quantitatively workers' physiological change, kinematics and kinetic factors without any restrictions of space in the greenhouse works.

In Vivo Study of Flow-Rate Accuracy of the MedStream Programmable Infusion System

Flow-rate accuracy and precision are important parameters to optimizing the efficacy of programmable intrathecal (IT) infusion pump delivery systems. Current programmable IT pumps are accurate within ±14.5% of their programmed infusion rate when assessed under ideal environmental conditions and specific flow-rate settings in vitro. We assessed the flow-rate accuracy of a novel programmable pump system across its entire flow-rate range under typical conditions in sheep (in vivo) and nominal conditions in vitro. The flow-rate accuracy of the MedStream Programmable Pump was assessed in both the in vivo and in vitro settings. In vivo flow-rate accuracy was assessed in 16 sheep at various flow-rates (producing 90 flow intervals) more than 90 ± 3 days. Pumps were then explanted, re-sterilized and in vitro flow-rate accuracy was assessed at 37°C and 1013 mBar (80 flow intervals). In vivo (sheep body temperatures 38.1°C-39.8°C), mean ± SD flow-rate error was 9.32% ± 9.27% and mean ± SD leak-rate was 0.028 ± 0.08 mL/day. Following explantation, mean in vitro flow-rate error and leak-rate were -1.05% ± 2.55% and 0.003 ± 0.004 mL/day (37°C, 1013 mBar), respectively. The MedStream Programmable Pump demonstrated high flow-rate accuracy when tested in vivo and in vitro at normal body temperature and environmental pressure as well as when tested in vivo at variable sheep body temperature. The flow-rate accuracy of the MedStream Programmable Pump across its flow-rate range, compares favorably to the accuracy of current clinically utilized programmable IT infusion pumps reported at specific flow-rate settings and conditions.

Effect of MRI strength and propofol sedation on pediatric core temperature change

To determine core body temperature variations in children undergoing MRI exams on 1.5 Tesla (T) and 3T magnetic field strengths and with and without propofol sedation. Temporal artery temperatures were prospectively collected on 400 consecutive patients undergoing 1.5 Tesla (T) or 3.0T MRI scans. A cumulative logistic regression model was created using age, weight, MRI protocol, sedation status, pre-MRI temperature and MRI strength to assess risk of temperature change. For patients with complete pre- and post-MRI temperature data, mean temperatures did not significantly change (-0.0155°C, 95%CI, -0.035, 0.064; n = 385). Temperature changes differed significantly between propofol-sedated and nonsedated patients (-0.26°C ± .44 versus 0.24°C ± 0.42; P < 0.0001), as did temperature changes for patients on the 3T (0.076°C ± 0.52) versus 1.5T (-0.06°C ± 0.48; P = 0.011). Sedation status, age, MRI strength, and MRI protocol accounted for 44.17% of temperature variance. The temperatures of 15 patients' (3.9%) decreased >1°C; 12 were on the 1.5T. All 7 patients (1.8%) who increased >1°C were non-sedates. Clinically significant core body temperature change is uncommon in children undergoing MRI with different magnetic field strengths, and with and without propofol sedation.