Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HIBERNATION, ARTIFICIAL”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources
PubMed2004

Supercooling ability in two populations of the land snail Helix pomatia (Gastropoda: Helicidae) and ice-nucleating activity of gut bacteria.

The land snail Helix pomatia (Gastropoda: Helicidae) is widely distributed in Northern and Central Europe where it may experience subzero temperatures during winter months. Its supercooling ability was studied in two populations of H. pomatia. One population originated from Southern Sweden (Gotaland) and the other from Central France (Auvergne). In the experimental design, they were acclimated, over 2 weeks, to artificial winter conditions (hibernation, T=5 degrees C). The Swedish snails showed a rather limited supercooling ability (temperature of crystallization, T(c)=-6.4+/-0.8 degrees C), significantly greater, however, than the supercooling capacity of the population from France (T(c)=-4.6+/-1.4 degrees C). In artificial spring conditions (3 months of hibernation followed by a progressive acclimation, over 2 weeks, to activity at T=20 degrees C), both populations exhibited a similar high T(c) (-2.0+/-1.0 degrees C). The lower T(c) of hibernating Swedish snails could be due to a greater loss of body water, accompanied by a higher concentration of solutes in the hemolymph. In both populations, the variation in hemolymph osmolality measured between hibernating (250-270 mOsm kg(-1)) and active (165-215 mOsm kg(-1)) snails may be explained by the variation in body water mass and did not suggest the production of colligative cryoprotectants. Moreover, the three bacterial strains, Buttiauxella sp., Kluyvera sp., and Tatumella sp. (Enterobacteriaceae) which were isolated from fed snails, but absent in starved snails, did not show any ice-nucleating activity at temperatures higher than -9 degrees C. Only the strain Kluyvera sp. initiated nucleation at -9 degrees C. This strain, therefore, is a weak, also termed a Type III or Class C ice-nucleating active bacterium, but with no influence on the supercooling ability of individual snails. In summary, fluctuations in body water mass of hibernating snail populations, triggering changes in osmolyte concentration, rather than the presence of endogenous ice-nucleating-active bacteria, accounts for fluctuations in their T(c).

Acclimatization↗
PubMed1983

Hibernation-hypothermia and metabolism in hedgehogs. Changes in water and electrolytes.

1. Hedgehogs seem not to suffer water loss during hibernation or hypothermia probably through water shifts from the interstitium to the cells and/or protein catabolism in tissues. 2. Higher potassium concentrations were retained in hedgehog's tissues, sodium and chloride ions rose in plasma, but ionic gradients were slightly affected. Probable reasons for increased calcium, magnesium and inorganic phosphorus were discussed. 3. Changes recorded during late fall indicated the predisposition of animals to hibernate, while changes during spontaneous and full arousals showed a reversed phenomenon in the hibernation cycle. 4. Artificially hypothermic animals in summer showed results similar to those of naturally hypothermic in winter, although lower in magnitude, suggesting a specific role of temperature in regulating the hibernation cycle.

Animals↗
PubMed1977

Blood acid-base state at a variable temperature. A graphical representation.

When blood temperature is changed in closed system ('anaerobic') conditions, plasma pH and PCO2 vary but no titration by external CO2, acid or alkaline equivalents takes place. It is therefore assumed that the overall acid-base state undergoes no fundamental change. This is further justified by the constancy of osmotic relationships between plasma and red cells, and to a lesser extent of relative alkalinity and protein alpha imidazole (Reeves, 1972, 1976a, b). These considerations serve as a basis for a correction procedure of pH and PCO2 of blood in open systems in vivo to a standard temperature T* (25 degrees C, eventually 37 degrees C). The temperature-corrected values pH* and P*CO2, and the derived [HCO3]* can be represented on a temperature-independent bicarbonate-pH diagram. This permits an easier interpretation of blood acid-base changes occurring together with body temperature variations, such as in ectotherms, hibernators or in artificial hypothermia. Extension to intracellular pH is considered.

Acid-Base Equilibrium↗
PubMedDate not supplied

[The effects of artificial analogue peptide TSKY isolated from the brain of hibernating ground squirrels in rats and mice].

Elevation of the i.c.v. injection dose of TSKY from 4 to 8 microg increased the movement activity of rats; in EEG theta- and beta-rhythms were enhanced and alpha-rhythm was suppressed. On the contrary, after treatment of 15 microg the rats fell into sleepy-like state; theta- and beta2-rhythms suppression, delta-, alpha- and beta1-rhythms were increased. Exposure under hypoxia-hypercapnia conditions reduced body temperature of mice to 18-19 degrees C, and maintain this state about 3-4 h after transferring into conventional gas medium. Preliminary cooling mice were administrated with TSKY that at dose 100 microg intraperitonally induced a prolonged hypothermia up to 12 h. Analogous injection without cooling raised mice temperature by 1.2 degrees C during about 2 h.

Alpha Rhythm↗
PubMed2004

Temperature-dependent changes in erythrocytes' cytosol state during natural and artificial hypobiosis.

At present, the question of how the structural state of the erythrocyte cytosol is arranged to maintain essential permeabilities successfully both at normal temperature and during periods with a significant body temperature reduction during hypobiosis remains unanswered. In the present work, we performed comparative investigations of temperature-dependent changes in the cytosol state of erythrocytes from animals subjected to natural (winter hibernating ground squirrels) or artificial hypobiosis. The cytosol state was evaluated by the ESR method of spin probes (TEMPON) within the temperature range of 0-50 degrees C. Erythrocyte resistance to acid hemolysis, which is limited by the permeability of membranes for protons and the state of the anion channel, were determined using the method described by Terskov and Getelson [Biofizika 2 (1957) 259]. A change in cytosol microviscosity of erythrocytes was found as well as a temperature-dependent increase in acid resistance of erythrocytes. Our investigations allow us to conclude that physiological changes occurring in a mammalian organism during natural and artificial hypobiosis are accompanied by structural modifications of the erythrocyte cytosol. The temperature range where these modifications are observed (8, 15, 40 degrees C) suggests that the most probable modifying link is spectrin and/or the sites of its interaction with membrane. The interaction of cytoskeletal components with the cell membrane plays a key role in regulation of membrane permeability, suggesting an important role of this interaction in the adaptive reactions of erythrocytes.

Animals↗
PubMedDate not supplied

[Lipid levels and lipid peroxidation in frog tissues during hyperthermia and hibernation].

The content of cholesterol, phospholipids, free fatty acids in the blood, ketone bodies and lipid peroxidation in the liver, brain, myocardium, skeletal muscles of Rana ridibunda were studied. Changes in the lipid content in blood during artificial hypothermia differ from those during hibernation and arousal. The utilization of reserve fats during hibernation is limited, but significantly rises during arousal. The ability to spontaneous lipid peroxidation under conditions of homogenate incubation at 37 degrees C does not increase in the studied tissues during hibernation.

Animals↗