Survival time of hypothermic white rats (15°C) and ground squirrels (10°C)

1960 ◽  
Vol 199 (3) ◽  
pp. 463-466 ◽  
Author(s):  
V. Popovic

The survival times of intensively cooled white rats decrease with their body temperatures. When cooled by Giaja's technique and maintained afterwards at a body temperature of 15°C rats survived 9 hours, but they could be revived by rewarming only during the first 5.5 hours of survival (biological survival). Similar biological survival times were found when the rats were cooled by other techniques, whether the cooling was much quicker or much slower. The survival time was also independent of the rate of rewarming from hypothermia. Survival was shortened by cooling after administration of sodium pentobarbital. Biological survival of young 40-gm rats at 15°C body temperature was 19 hours, 14 hours longer than that of hypothermic adults. Level of O2 consumption of hypothermic young rats differed from those of hypothermic adult animals.

1963 ◽  
Vol 18 (5) ◽  
pp. 1016-1018 ◽  
Author(s):  
J. A. Panuska ◽  
Vojin Popovic

Inexperienced shaved adult white rats cooled to a colonic temperature of 18.5 C and then rewarmed to 26.0 C, were placed at an ambient temperature of 2.0 C with the possibility of using a lever-activated heat reinforcement apparatus. Their body temperatures leveled at 29 C; and during the next 40–80 min the rats either learned to press the lever systematically for external heat and thereby rewarmed themselves to euthermia, or they drifted into deeper hypothermia leading to death. Activity records and visual observations indicate that after an average of 48 min and at a body temperature of 29.6 C (28.5–30.2 C), out of a group of 14 rats 12 learned this technique necessary for their survival. All 12 rats reached euthermia and continued to use the lever as long as they remained in the experimental situation. It is concluded that learning is possible even at a low body temperature of 29.6 C. performance; heat reinforcement; temperature regulation; body temperature; environmental temperature; operant behavior; survival studies; motivation; physiology of learning; cold physiology Submitted on March 7, 1963


2020 ◽  
Vol 56 (5) ◽  
pp. 270-279
Author(s):  
Shannon Marie Palermo ◽  
Dorothy C. Brown ◽  
Stephen J. Mehler ◽  
Mark P. Rondeau

ABSTRACT Pancreatitis in dogs may lead to extrahepatic bile duct obstruction as a result of local inflammation. Medical records of 45 client-owned dogs with clinical suspicion of extrahepatic bile duct obstruction secondary to pancreatitis were reviewed to determine clinical findings, outcome, and factors associated with survival. Survival times were determined using the Kaplan-Meier product limit method. Cox multivariable survival methods were employed to determine factors associated with survival time following diagnosis. The median survival time was 241 days (95% confidence interval [CI] 25–631), with 34 of 45 dogs (76%) surviving to discharge. Dogs 9 yr of age or older with azotemia at presentation had a 9.9 greater hazard for death (95% CI 2.5–38.1; P = .001) compared with dogs younger than 9 yr old without azotemia at presentation. Dogs without subjective ultrasonographic gallbladder distension had a 4.4 greater hazard for death (95% CI 1.3–15.4; P = .018) compared with dogs with subjective gallbladder distension. Dogs with a body temperature ≥102.5°F at admission had a 3.1 greater hazard for death (95% CI 1.3–7.7; P = .013) than dogs with a body temperature <102.5°F at admission. This information may help clinicians discuss prognosis with owners of affected dogs.


1963 ◽  
Vol 204 (5) ◽  
pp. 949-952 ◽  
Author(s):  
Pava Popovic ◽  
Vojin Popovic

Six of seven 2-day-old ground squirrels survived without any harmful consequences 11 hr supercooling to body temperatures of –3 to –4 C. Longer exposure at the same body temperature was not followed by survival. Of 12 ground squirrels which were kept at stabilized body temperatures of –6 and –8 C for 5 hr, 10 animals survived. Electrical activity of the heart was not detectable when the body temperature of ground squirrels was below –2 C. Immersion of newborn ground squirrels in –35 C alcohol-dry-ice mixture caused their bodies to freeze after 15–20 sec, suddenly turning white and rigid. Ground squirrels survived the freezing which lasted less than 2 min. At the end of 2 min immersion the esophageal temperature of cooled animals was –10 to –15 C.


1957 ◽  
Vol 188 (2) ◽  
pp. 277-280 ◽  
Author(s):  
Frederick E. Samson ◽  
Nancy A. Dahl

The survival times of neonatal rats in nitrogen with and without injected iodoacetic acid and at diverse ages and temperatures are presented. It is shown that the survival time in nitrogen is greatly shortened if iodoacetic acid has been injected. Also, in iodoacetic acid treated rats the survival time is decreased with the daily development of the animal; the survival time is lengthened by a decrease in body temperature; the effect of temperature decreases with the daily development of the animal; the logarithm of the survival time has a linear relationship with the body temperature. It is concluded that these survival times are a measure of the energy requirement of the respiratory centers and the influence of age and temperature upon the requirement. A calculation is made which indicates that a deficiency of one micromole of energy-rich phosphate per gram of tissue in the respiratory centers results in the cessation of respiratory movements.


2021 ◽  
Author(s):  
Anusha Shankar ◽  
Isabelle NH Cisneros ◽  
Sarah Thompson ◽  
Catherine H Graham ◽  
Donald R Powers

Many small endotherms use torpor, saving energy by a controlled reduction of their body temperature and metabolic rate. Some species (e.g. arctic ground squirrels, hummingbirds) enter deep torpor, dropping their body temperatures by 23-37 °C, while others can only enter shallow torpor (e.g., pigeons, 3-10 °C reductions). However, deep torpor in mammals can increase predation risk (unless animals are in burrows or caves), inhibit immune function, and result in sleep deprivation, so even for species that can enter deep torpor, facultative shallow torpor might help balance energy savings with these potential costs. Deep torpor occurs in three avian orders. Although the literature hints that some bird species can use both shallow and deep torpor, little empirical evidence of such an avian torpor spectrum exists. We infrared imaged three hummingbird species that are known to use deep torpor, under natural temperature and light cycles, to test if they were also capable of shallow torpor. All three species used both deep and shallow torpor, often on the same night. Depending on the species, they used shallow torpor for 5-35% of the night. The presence of a bird torpor spectrum indicates a capacity for fine-scale physiological and genetic regulation of avian torpid metabolism.


1965 ◽  
Vol 20 (6) ◽  
pp. 1275-1277 ◽  
Author(s):  
J. A. Panuska ◽  
V. P. Popovic

Fifty-one previously untrained adult white rats were cooled to colonic temperature of 18.5 C and were rewarmed to various body temperatures between 23 and 31 C. After their body temperature stabilized at a chosen level, rats were placed in a chamber with the possibility of using a lever-activated heat reinforcement apparatus. The temperature of the chamber was 2 C. Each experiment lasted 180 min. During this time the rats either started to press the lever steadily for external heat or at the end of this experiment they became even more hypothermic. In a group of 41 rats kept at a body temperature of 25 C or above, 38 animals used the simple heat reinforcement apparatus and responded effectively, thus rewarming themselves to euthermia. Animals at a higher body temperature acquired the response earlier than animals whose body temperature was lower. When the body temperature was 25 C or below, the rats failed to acquire the response. Thus it appears that body temperature of 25 C is a critical body temperature for this simple response acquisition. behavioral temperature regulation; body temperature; heat reinforcement; hypothermia; learning; performance Submitted on April 1, 1965


1959 ◽  
Vol 196 (2) ◽  
pp. 325-326 ◽  
Author(s):  
Frederick E. Samson ◽  
William M. Balfour ◽  
Nancy A. Dahl

The survival times and the cerebral ATP concentrations during anoxia have been determined. Rats were subjected to anoxia for a measured time, returned to air and survival determined. For ATP determinations, rats were frozen in liquid nitrogen following the anoxia, and the brain analyzed by the firefly luminescence method. The survival time (ST50) in anoxia is 63 seconds. During the first 20 seconds, the ATP remains at 2µM/gm; it then falls to 1.0 µM/gm at 65 seconds. When glycolysis is inhibited by sodium iodoacetate the ST50 decreases to 10 seconds; the ATP remains unchanged for 5 seconds and then decreases rapidly (0.14 µM/gm/sec.) to 1.0 µM/gm at 10 sec. Cooling the animal to 25, 20 or 15°C for 10 minutes increases the ST50 and decreases the rate of ATP disappearance. The ATP concentration at the corresponding ST50 increases with decreasing body temperature.


2021 ◽  
Vol 12 ◽  
Author(s):  
D.L. Levesque ◽  
J. Nowack ◽  
J.G. Boyles

There is increasing recognition that rather than being fully homeothermic, most endotherms display some degree of flexibility in body temperature. However, the degree to which this occurs varies widely from the relatively strict homeothermy in species, such as humans to the dramatic seasonal hibernation seen in Holarctic ground squirrels, to many points in between. To date, attempts to analyse this variability within the framework generated by the study of thermal performance curves have been lacking. We tested if frequency distribution histograms of continuous body temperature measurements could provide a useful analogue to a thermal performance curve in endotherms. We provide examples from mammals displaying a range of thermoregulatory phenotypes, break down continuous core body temperature traces into various components (active and rest phase modes, spreads and skew) and compare these components to hypothetical performance curves. We did not find analogous patterns to ectotherm thermal performance curves, in either full datasets or by breaking body temperature values into more biologically relevant components. Most species had either bimodal or right-skewed (or both) distributions for both active and rest phase body temperatures, indicating a greater capacity for mammals to tolerate body temperatures elevated above the optimal temperatures than commonly assumed. We suggest that while core body temperature distributions may prove useful in generating optimal body temperatures for thermal performance studies and in various ecological applications, they may not be a good means of assessing the shape and breath of thermal performance in endotherms. We also urge researchers to move beyond only using mean body temperatures and to embrace the full variability in both active and resting temperatures in endotherms.


2019 ◽  
Vol 3 (s1) ◽  
pp. 37-37
Author(s):  
Jo Ellen Wilson ◽  
Sarasota Mihalko ◽  
Stephan Heckers ◽  
Pratik P. Pandharipande ◽  
Timothy D. Girard ◽  
...  

OBJECTIVES/SPECIFIC AIMS: Delirium, a form of acute brain dysfunction, characterized by changes in attention and alertness, is a known independent predictor of mortality in the Intensive Care Unit (ICU). We sought to understand whether catatonia, a more recently recognized form of acute brain dysfunction, is associated with increased 30-day mortality in critically ill older adults. METHODS/STUDY POPULATION: We prospectively enrolled critically ill patients at a single institution who were on a ventilator or in shock and evaluated them daily for delirium using the Confusion Assessment for the ICU and for catatonia using the Bush Francis Catatonia Rating Scale. Coma, was defined as a Richmond Agitation Scale score of −4 or −5. We used the Cox Proportional Hazards model predicting 30-day mortality after adjusting for delirium, coma and catatonia status. RESULTS/ANTICIPATED RESULTS: We enrolled 335 medical, surgical or trauma critically ill patients with 1103 matched delirium and catatonia assessments. Median age was 58 years (IQR: 48 - 67). Main indications for admission to the ICU included: airway disease or protection (32%; N=100) or sepsis and/or shock (25%; N=79. In the unadjusted analysis, regardless of the presence of catatonia, non-delirious individuals have the highest median survival times, while delirious patients have the lowest median survival time. Comparing the absence and presence of catatonia, the presence of catatonia worsens survival (Figure 1). In a time-dependent Cox model, comparing non-delirious individuals, holding catatonia status constant, delirious individuals have 1.72 times the hazards of death (IQR: 1.321, 2.231) while those with coma have 5.48 times the hazards of death (IQR: 4.298, 6.984). For DSM-5 catatonia scores, a 1-unit increase in the score is associated with 1.18 times the hazards of in-hospital mortality. Comparing two individuals with the same delirium status, an individual with a DSM-5 catatonia score of 0 (no catatonia) will have 1.178 times the hazard of death (IQR: 1.086, 1.278), while an individual with a score of 3 catatonia items (catatonia) present will have 1.63 times the hazard of death. DISCUSSION/SIGNIFICANCE OF IMPACT: Non-delirious individuals have the highest median survival times, while those who are comatose have the lowest median survival times after a critical illness, holding catatonia status constant. Comparing the absence and presence of catatonia, the presence of catatonia seems to worsen survival. Those individual who are both comatose and catatonic have the lowest median survival time.


1961 ◽  
Vol 23 (1) ◽  
pp. 69-77 ◽  
Author(s):  
S. KULLANDER ◽  
B. SUNDÉN

SUMMARY A total of twenty-three human pre-viable foetuses (7–400 g.) were removed by abdominal hysterotomy (legal abortions) and studied during survival in an anoxic state at different temperatures. The duration of survival, as judged by ECG waves, at 37° c was about 3 hr.; it was longer for female foetuses than for males, and longer for large foetuses than for small ones. General reduction of the body-temperature to 4° c during periods varying between 30 min. and 6 hr. with subsequent rewarming to and maintenance at 37° c increased the survival time by a further 1–2 hr. The blood sugar did not decrease either during the period of survival or during hypothermia, but the non-protein nitrogen increased, while acidosis and hyperkalaemia developed. The glycogen content of the liver decreased during the anoxic period of survival and diminished further during hypothermia. The adrenal glands produced adrenaline in addition to noradrenaline during the anoxic phase, and this may occur in a very early stage of intrauterine life.


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