Monotreme Cell-Cycles and the Evolution of Homeothermy

1988 ◽  
Vol 36 (5) ◽  
pp. 573 ◽  
Author(s):  
JM Watson ◽  
JAM Graves
Keyword(s):  
Body Temperature ◽  
Cycle Time ◽  
Low Temperatures ◽  
Evolutionary History ◽  
The Body ◽  
Lethal Temperature ◽  
Cell Cycles ◽  
M Phase ◽  
Effects Of Temperature ◽  
High And Low Temperatures

We have studied the effects of temperature on the phases of the cell cycle in cells derived from the monotreme mammals, platypus and echidna, which have the unusually low body temperature of 32�C. We report here that M phase and the cycle time conform to expectations, but in the case of cycle time this is due to different effects of high and low temperatures on GI, G2 and S phases. The finding that the G2 and S phases apparently have an inverse linear relationship with temperature up to 37�C (the upper lethal temperature) suggests that the low body temperature of the monotremes is not primitive, but rather has been the result of a lowering of the body temperature during their evolutionary history.

Effect of t° on blood clotting

1927 ◽  
Vol 23 (11) ◽  
pp. 1175-1175
Author(s):  
I. G. Klebansky
Keyword(s):  
Body Temperature ◽  
Blood Coagulation ◽  
Low Temperatures ◽  
Blood Clotting ◽  
The Body ◽  
Constant Rate

According to studies of I.G. Klebansky blood clotting in warm-blooded animals occurs at a constant rate at a certain temperature, the optimum of which is close to the body temperature of animals. At low temperatures blood coagulation is extremely slowed down, but not accelerated.

scholarly journals Always a price to pay: hibernation at low temperatures comes with a trade-off between energy savings and telomere damage

2019 ◽  
Vol 15 (10) ◽  
pp. 20190466 ◽  
Author(s):  
Julia Nowack ◽  
Iris Tarmann ◽  
Franz Hoelzl ◽  
Steve Smith ◽  
Sylvain Giroud ◽  
...  
Keyword(s):  
Body Temperature ◽  
Low Temperatures ◽  
Energy Demand ◽  
Energy Savings ◽  
High Energy ◽  
Cellular Level ◽  
The Body ◽  
Temperature Differential ◽  
Lower Temperature ◽  
Telomere Dynamics

We experimentally tested the costs of deep torpor at low temperatures by comparing telomere dynamics in two species of rodents hibernating at either 3 or 14°C. Our data show that hibernators kept at the warmer temperature had higher arousal frequencies, but maintained longer telomeres than individuals hibernating at the colder temperature. We suggest that the high-energy demand of frequent arousals is counteracted by a lower temperature differential between torpid and euthermic body temperature and that telomere length is restored during arousals when the body temperature is returned to normothermic values. Taken together, our study shows that hibernation at low body temperatures comes with costs on a cellular level and that hibernators need to actively counterbalance the shortening of telomeres.

Design of a Novel Temperature Self-Operating Protective Clothing Based on Phase Change Material

2012 ◽  
Vol 627 ◽  
pp. 160-163
Author(s):  
Tai Qi Liu ◽  
Fu Rui Ma ◽  
Qi Song Shi ◽  
Jin Fang Chu ◽  
Tan Qiu Li ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Low Temperatures ◽  
Protective Clothing ◽  
Thermal Stresses ◽  
The Body ◽  
Large Heat ◽  
High And Low Temperatures ◽  
Change Material ◽  
Inorganic Composite

The clothing containing phase change material (PCM) with function of absorbing the body-released heat has wide applications. In this paper, a novel protective clothing based phase change material was investigated. The results show that PCM has suitable melting temperature, large heat flow, stability after repeating applications, and it is convenient for application in cooling. Moreover, the manufacturing process has a great affect on the property of the titled material. The above inorganic composite was selected to prepare the temperature self-operating protective clothing, which can efficiently lighten the demic thermal stresses at high and low temperatures.

The influence of ambient temperature and humidity on the body temperature and water loss from two Australian lizards, Tiliqua rugosa (Gray) (Scincidae) and Amphibolurus barbatus cuvier (Agamidae)

1965 ◽  
Vol 13 (2) ◽  
pp. 331 ◽  
Author(s):  
. Warburg.M.R
Keyword(s):  
Body Temperature ◽  
Water Loss ◽  
Early Morning ◽  
The Body ◽  
Limiting Factor ◽  
Lethal Temperature ◽  
Natural Conditions ◽  
Tiliqua Rugosa ◽  
Physiological Adaptations ◽  
Varied Diet

Tiliqua rugosa and Amphibolurus barbatus are capable of living in arid habitats; they display modified behaviour and corresponding physiological adaptations. The activity pattern of T. rugosa changes during the year with activity restricted during midsummer to short periods in the early morning and late afternoon. The body temperature of T. rugosa under natural conditions indicates that 41�C is the highest temperature tolerated naturally. In the controlled temperature cabinet a lizard of this species survived for 2 hr at a body temperature of 41.7�C, whilst the lethal temperature was 45.5�C. For A. barbatus the lethal temperature was 46.0�C, and one specimen survived for 2 hr at 43.5�C. The thermoregulation temperature (T.T.) of T. rugosa as calculated from field data was 37.5�C; above this temperature the body temperature of this lizard was below that of the air. Temperature regulation in this species was also studied in the laboratory under controlled conditions. Water loss by evaporation was remarkably low in both lizards even when compared with better adapted, desert lizards. The rate of water loss is directly related to temperature and inversely related to humidity. T. rugosa loses most water during the first period of exposure (about 2 hr) to temperatures between 30-37.5�C, whilst A. barbatus loses water more slowly. At high temperatures (i.e. over 40�C) the rate of water loss decreases. Even in areas where no surface water is available T. rugosa appears to survive because its varied diet supplies adequate water. It is unlikely that food is a limiting factor in its distribution.

Behavioral thermoregulation in the pika Ochotona princeps: a field study using radiotelemetry

1974 ◽  
Vol 52 (3) ◽  
pp. 353-358 ◽  
Author(s):  
Robert A. MacArthur ◽  
Lawrence C. H. Wang
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Field Study ◽  
Negative Correlation ◽  
Resting State ◽  
The Body ◽  
Behavioral Thermoregulation ◽  
Lethal Temperature ◽  
Level Of Activity ◽  
Maximum Fluctuation

When either the level or duration of spontaneous activity is increased over an ambient temperature range of 2–28C, the body temperature of the pika shows a slight increase; the maximum fluctuation observed was 1.0C. However, none of the changes in body temperature proved to be significantly different from that of the resting state (P < 0.05).In nature, pikas avoid hyperthermia by means of precise behavioral thermoregulation in which both duration and level of activity are regulated. A negative correlation was observed between the duration of lime spent on the surface of the rocks, and the surface ambient temperature, over a range of 3–27C. Between 0930 and 1930 h, as the surface ambient temperature increased, the percentage of observations in which the pika was below the rocks increased, and vice versa. By engaging in short bursts of surface activity (usually less than a 3.5-min duration) followed by retreat to the cooler microclimate beneath the rocks, pikas are able to regulate their body temperature precisely at a level only 2–3C below the upper lethal temperature.

scholarly journals Note on the Temperature Tolerances of some Intertidal animals in Relation to Environmental Temperatures and Geographical Distribution

1958 ◽  
Vol 37 (1) ◽  
pp. 49-66 ◽  
Author(s):  
A. J. Southward
Keyword(s):  
Geographical Distribution ◽  
Low Temperatures ◽  
Causal Relation ◽  
Field Measurements ◽  
Weather Conditions ◽  
The Body ◽  
Body Temperatures ◽  
Sea Temperature ◽  
Heating Effects ◽  
High And Low Temperatures

In experiments on four species of barnacles and four species of top-shells, the barnacles were found to be more resistant to high or low temperatures than the top-shells. Among each group of animals the degree of tolerance was related to the geographical distribution of the species and their zonation on the shore. Thus most tolerance of high temperature was shown by species of southern distribution, especially by those occurring at the upper limit of the midlittoral zone, and most tolerance of low temperature by species of northern distribution. Least tolerance of high and low temperatures was shown by species found only in the infralittoral fringe or below low water.Field measurements of the body temperatures of barnacles and limpets while exposed to the air were made with thermocouples. Under many weather conditions the body temperatures were higher than would be expected from local meteorological values of air temperature. This difference was due to retention of sea temperature by the animals and the rocks and to the heating effects of sunlight.The results of the laboratory experiments and of the field measurements are discussed together in relation to weather and geographical distribution. It is clear that the temperatures experienced on the shore are well within the tolerance limits of most of the animals, and even exceptional extremes of temperature may have little direct influence on the distribution of adult intertidal animals. Evidence for a causal relation between temperature and distribution must be sought in non-lethal terms such as debilitating effects, or indirectly through competition between species, or in combination with other factors.

scholarly journals Survival Dynamics of Aphanomyces cochlioides Oospores Exposed to Heat Stress

2007 ◽  
Vol 97 (4) ◽  
pp. 484-491 ◽  
Author(s):  
A. T. Dyer ◽  
C. E. Windels ◽  
R. D. Cook ◽  
K. J. Leonard
Keyword(s):  
Low Temperatures ◽  
Weibull Model ◽  
Model Parameters ◽  
Heat Damage ◽  
Aphanomyces Cochlioides ◽  
Heat Effects ◽  
Effects Of Temperature ◽  
High And Low Temperatures ◽  
Lethal Doses ◽  
Increased Susceptibility

To determine how exposure to heat effects their survival, oospores of Aphanomyces cochlioides isolate C22 were exposed in water to 35, 40, 45, or 50°C for prescribed times and then examined for viability. The Weibull model was modified to represent the effects of temperature on survival of oospores. The final fitted model gave lethal doses for 50% of the oospores of 251, 49.8, 9.8, and 1.9 h at 35, 40, 45, and 50°C, respectively. To determine if alternating high and low temperatures resulted in (i) recovery from heat damage during low temperature periods, (ii) increased susceptibility to heat damage, or (iii) if effects of heat damage were cumulative, oospores were examined after each of four 24-h cycles at 45°C for 4 h and 21°C for 20 h. Survival of oospores exposed to alternating high and low temperatures fit the cumulative effects model. Significant variability in heat tolerance among five isolates was observed (P< 0.001) but model parameters successfully accommodated this variability (R2 = 0.96, P < 0.001). This research shows that under wet conditions, there are predictable patterns to mortality for A. cochlioides oospores exposed to continuous or fluctuating high temperatures.

a Novel Combinational Nanodrug Delivery System Induces Synergistic Inhibition of Lung Adenocarcinoma Cells in vitro

2020 ◽  
Vol 17 ◽  
Author(s):  
Mingliang Fan ◽  
Jiping Li
Keyword(s):  
Lung Adenocarcinoma ◽  
Delivery System ◽  
The Body ◽  
Anticancer Efficacy ◽  
Nanodrug Delivery ◽  
Drug Molecules ◽  
Cellular Assays ◽  
Lung Adenocarcinoma Cell Line ◽  
M Phase

Background: The combination of two or more therapeutic drugs is an attractive approach to improve the treatment of experimental tumors. Leveraging nanocarriers for combinational drug delivery can allow a control over drug biological fate and promote co-localization in the same area of the body. However, there are certain concerns regarding the biodegradability and potential long-term toxicity arising from these synthetic nanoscale carriers. Objective: Our aim was to develop a combinational nanodrug delivery system formed by self-assembling of amphiphilic drug molecules，minimizing potential toxicities associated with using additional synthetic nanocarriers. Methods: A novel prodrug chlorambucil gemcitabine conjugate was synthesized, this prodrug was used for the encapsulation of an additional hydrophobic anticancer drug paclitaxel, taking the form of combinational nanodrugs. Particle size and zeta potential were evaluated, cytotoxicity assay and apoptosis/cell cycle analysis were also performed to validate the anticancer efficacy of the combinational nanodrugs. Results: The combinational nanodrugs were acquired by means of nanoprecipitation. In A549 lung adenocarcinoma cell line, cellular assays revealed that co-delivery of low dosage paclitaxel with chlorambucil gemcitabine conjugate can act synergistically to inhibit cell growth and induce accumulation of cells in the G2/M phase with a concomitant decrease in G0/G1 compartment. Conclusion: Chlorambucil gemcitabine conjugate and paclitaxel can co-assemble into composite nanoparticles by a nanoprecipitation process and the resulting combinational nanodrugs showed synergistic anticancer effect. This synthetic nanocarrier-free approach might broaden the nanodrug concept and have potential in cancer therapy.

Antipyretic Plants: An Updated Review

2020 ◽  
Vol 16 (1) ◽  
pp. 4-12
Author(s):  
Vandana Garg ◽  
Rohit Dutt
Keyword(s):  
Side Effects ◽  
Body Temperature ◽  
Medicinal Plants ◽  
Inflammatory Mediators ◽  
Review Paper ◽  
The Body ◽  
Hypothalamic Area ◽  
Antipyretic Activity ◽  
Disease States ◽  
Elevated Body Temperature

Background: Fever, is known as pyrexia, may occur due to infection, inflammation, or any tissue damage and disease states. Normally, the infected or damaged tissue initiates the enhanced formation of pro-inflammatory mediators like cytokines which further increases the synthesis of prostaglandin E2 (PgE2) near the hypothalamic area and thereby trigger the hypothalamus to elevate the body temperature. Objective: Antipyretics are the agents which reduce the elevated body temperature. The most commonly used antipyretic agent, paracetamol, may be fatal due to its side effects. Methods: In this review paper, Chemical Abstracts, Google Scholar, PubMed, and Science Direct were the sources for the published article to collect information regarding antipyretic activity. Results: This review compiles the antipyretic plants that may be useful to treat fever due to various diseases. Conclusion: These medicinal plants could be good alternatives for traditional allopathic antipyretics.

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