[Cold and hypoxia tolerance of rat embryos].
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Animals↗
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[Effects of nonthermal stresses on brown adipose tissue thermogenesis].
Repetitive intermittent immobilization stress has been shown to induce an improved cold tolerance through an enhanced capacity of nonshivering thermogenesis (NST). In the present study, effects of immobilization (3 hrs daily for 4-5 weeks), exercise training (running with treadmill 30 min daily, 30 m/min under 8 degrees inclination for 4-5 weeks) and chronic corticosterone treatment (subcutaneous injection at a dose of 0.3 mg/100 g for 4-5 weeks) were investigated on in vitro and/or in vivo thermogenesis of rat interscapular brown adipose tissue (BAT). BAT thermogenesis in vitro was measured in the minced tissue blocks in Krebs-Ringer phosphate buffer using a Clark type oxygen electrode. DNA content per whole BAT pad was greater in the stressed rats, while it was not affected by exercise training and corticosterone. Noradrenaline-and glucagon-stimulated oxygen consumptions were significantly greater in the stressed rats, while significantly smaller in the trained rats as compared with respective controls. Corticosterone treatment failed to affect those values in terms with both per mg tissue and per whole tissue pad, except the less noradrenaline-stimulated oxygen consumption in terms with per mg tissue and DNA. In vivo thermogenesis was assessed by the changes of temperatures in colon (Tcol), BAT (TBAT) and tail skin (Tsk) induced by noradrenaline or glucagon infusion under anesthesia Noradrenaline and glucagon increased the TBAT and the extent of increase was greater in the stressed rats. These results indicated: 1. Repetitive immobilization stress induces the tissue hyperplasia and enhances thermogenic activity of BAT. 2. Exercise training suppresses BAT thermogenesis. 3. Chronic corticosterone administration does not affect BAT thermogenesis. It may be concluded that the enhancing or suppressing effect of nonthermal stress on BAT thermogenesis is due to other factor(s) than corticosterone.
Adipose Tissue↗
[Effects of low and subzero temperature on a Plutella xylostella laboratory population].
In this study, the effects of low (< 8 degrees C) and subzero temperature on the development, survival and reproduction of Plutella xylostella were examined. The mortality of its egg and pupae at 4 degrees C and 6 degrees C increased with time, no egg and pupae could complete their development at these low temperatures, and all died after 55 days and 70 days, respectively. When the pupae were placed at 4 degrees C and 6 degrees C for various durations and then moved to 16 degrees C for development, the fecundity of the resultant adults was reduced, and the longer the duration at 4 degrees C and 6 degrees C, the further the fecundity was reduced, and the fecundity was reduced to zero when the pupae were retained at these low temperatures for 45 days. The survival of this insect was observed following exposure of various stages of this insect to temperatures below 0 degree C. The results showed that the mortality of all preimaginal stages increased with decreased temperature and prolonged duration. The ability of cold tolerance of the various stages of this insect was in order of the third instar and pupa > the second and forth instars > the first instar and egg. Temporal exposure to temperatures below 0 degree C affected the development of subsequent stages at a favorable temperature. Generally, the developmental time of the subsequent stages increased, and the largest increase of development time was observed with the stage next to the stage treated at low temperatures. Exposure of the pupal stage to low temperature also reduced the fecundity of the resultant female adults, and the reduction was positively correlated to lower temperature and longer exposure.
Animals↗
Perspectives on the improvement of quality of life with epoetin alfa therapy.
Epoetin alfa (recombinant human erythropoietin) effectively diminishes the anemia associated with end-stage renal disease (ESRD). Although many clinical manifestations of ESRD have been attributed to uremic toxins, the ability of epoetin alfa therapy to improve several of these conditions, such as diminished energy levels, appetite, cold tolerance, sexual function, and cognitive abilities, suggests that anemia may be an important factor in uremia-associated symptoms. Correction of this anemia results in improvements in the patient's quality of life. These improvements can be measured by objective criteria such as exercise tolerance tests, or by subjective standards such as patient response to questionnaires. In studies to date, both subjective and objective data show that epoetin alfa therapy significantly improves the quality of life of patients with ESRD.
Activities of Daily Living↗
Carbohydrate metabolism under environmental stress. II. Glucose tolerance under heat, cold and hypoxic stress.
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Animals↗
Treatment of obesity with thermogenic beta-adrenoceptor agonists: studies on BRL 26830A in rodents.
Studies on BRL 26830A in rodents have shown that thermogenic beta-adrenoceptor agonists have potential for the therapy of obesity. BRL 26830A reduced body weight gain in ob/ob mice and fa/fa rats by reducing lipid accumulation. It had no effect on lean body mass. BRL 26830A did not reduce food intake, its anti-obesity effect being due to stimulation of energy expenditure. This thermic effect was enhanced in the obese animals by repeat dosing. BRL 26830A did not affect body weight gain in the lean counterparts of the obese animals because its thermic effect in lean animals was reduced by repeat dosing. Brown adipose tissue is an important site of BRL 26830A-induced thermogenesis. A single dose of BRL 26830A raised brown adipose tissue temperature, depleted brown adipose tissue lipid and unmasked GDP-binding sites in brown adipose tissue mitochondria. Repeat dosing caused hypertrophy of brown adipose tissue and improved cold tolerance in mice. In-vitro studies showed that the rat brown adipocyte beta-adrenoceptor does not fall into the beta 1/beta 2 classification and BRL 28410, which mediates the biological effects of BRL 26830A in vivo, selectively stimulated the brown adipocyte receptor. It is concluded that BRL 26830A achieves its anti-obesity effect by mimicking natural mechanisms involved in thermogenesis and the control of body weight.
Adipose Tissue, Brown↗
[Bacteriological aspects of holding freshly prepared spinach at warm temperatures. Relation between bacterial count and nitrate reduction].
In sterilized spinach which was inoculated with bacteria, a reduction of NO3- to NO2-, due to their metabolic activity, was detectable, depending on the holding conditions. The reaction rate was highest in the presence of thermophilic bacteria. A lower reaction rate was altogether found with mesophilic bacteria which, depending on counts and holding time, may temporarily cause high nitrite contents. The reaction rate was lowest with cold-tolerant bacteria.
Food Microbiology↗
[Nutritional adaptation in brown adipose tissue thermogenesis--with special reference to overfeeding and iron deficiency].
The effect of sucrose overfeeding and low iron diet on brown adipose tissue (BAT) thermogenesis of rats has been investigated from the view point of in vitro BAT oxygen consumption and BAT fatty acids (FA) compositions in rats. Control group was fed on a standard diet with tap water, sucrose group was on the standard diet and 32% sucrose solution, and iron deficient group on a low iron diet with tap water. In vitro interscapular BAT thermogenesis as estimated by oxygen consumption was measured in minced tissue blocks in Krebs-Ringer phosphate buffer using a Clark oxygen electrode. In sucrose overfeeding rats, caloric intake was greater than in controls, but did not differ body weight. Interscapular BAT weight and DNA content were greater. Colonic and tail skin temperatures were higher. Basal oxygen consumption was higher. Noradrenaline- and glucagon-stimulated oxygen consumptions did not differ when expressed per DNA, but significantly greater per whole tissue pad. Both BAT-triglyceride (TG) and -phospholipid (PL) levels were higher. Polyunsaturated FA were lower, while monosaturated FA were higher in both BAT-TG and -PL. In iron deficient rats, BAT weight and DNA content were higher. Colonic and tail skin temperatures did not differ. Although basal oxygen consumption did not differ, noradrenaline-stimulated oxygen consumption was less per DNA, but did not differ per whole tissue pad, while glucagon-stimulated oxygen consumption was less when expressed per DNA, as well as whole tissue pad. Cold-tolerance as assessed by the fall in colonic temperature at 0 degree C was decreased. BAT-TG and -PL levels did not differ. Polyunsaturated FA were higher in both BAT-TG and -PL. These findings indicated that sucrose-induced overfeeding enhances BAT thermogenesis mainly by tissue hyperplasia, while iron deficiency suppresses BAT thermogenic response, although it causes the compensatory tissue hyperplasia.
Adaptation, Physiological↗
[Reconstruction of isolated traumatic amputation of the thumb. Role of annular pollicization].
Fifteen pollicisations of undamaged ring fingers were carried out after isolated thumb amputations, occurring most of the time above the MP in manual workers. All these patients were re-examined with a minimum two years' follow-up and an average 5 years'. There was no complication, and all the patients operated on resumed an active work at the fifth postoperative month on average. Early rehabilitation was favoured by bone fixation of the first metacarpal with an intramedullary peg, and by careful cinematisation (reinsertion of all extensors, cinematisation by the flexor pollicis longus). The results showed that this procedure was the surgery of choice for isolated amputations of the thumb occurring in manual workers at the level of or above the MP. Indeed, if it is compared with transfers of the 2nd toe, pollicisation is characterized by its reliability, an early return to work, a greater range of active motion (60 degrees instead of 30 degrees), pulp-pinch and key-pinch figures at 54 per cent, a hand-grasp (70 per cent) identical or better, a touch sensibility two or three times as good (Weber at 5 mm), a better cold tolerance (no professional disability), and by the fact that there is no discomfort at the level where the transplanted digit was removed.
Adult↗
[Seasonal variation in the ultrastructure and calcium uptake rate of cardiac sarcoplasmic reticulum in ground sqirrel].
The ultrastructure and calcium uptake rate of the cardiac sarcoplasmic reticulum (SR) was quantatively compared between the ground squirrels (Citellus dauricus) in hibernating and non-hibernating season. (1) In our ultrastructural investigation, OsFeCN post-fixation method was used to enhance the staining of SR, which made the SR structure more recognizable. (2) The results of morphometrical analysis demonstrated that the volume density of SR and lipid droplet in the cardio-myocyte was significantly higher (P < 0.01) in the hibernating animal than in the summer active one, and the subcompartment of SR with this difference was non-junctional SR. (3) The cardiac SR from hibernating ground squirrels had a higher (P < 0.01) calcium uptake rate as measured by the absorbence of arsenazo-III Ca2+ indicator, than that from autumn active ones. Altogether, our results suggested that the function of SR in the uptake of cytosolic calcium was enhanced in hibernating season, which may play an important role in the cold tolerance of myocardium of a hibernator.
Animals↗
[Experimental analysis of the calcium source for cardiac excitation-contraction coupling in hibernator Citellus dauricus].
The force-interval and force-frequency relationships and the effects of Cd2+ and ryanodine on the myocardial action potential and contraction were compared between hibernating (HGS) and active (AGS) ground squirrels Citellus dauricus. (1) Raising the driving frequency caused a negative inotropic effect in the AGS group, but a biphasic change with an increase of the peak force followed by a decrease in the HGS group. The contraction in HGS group exhibited a more pronounced post-interval potentiation, and was more significantly modulated by the driving frequency. (2) HGS animals displaged action potentials of shorter early-stage duration and stronger contractions of shorter time course in comparison with the AGS animals. Both the action potential and the contraction of HGS group were less affected by Cd2+, but the contraction was more significantly inhibited by ryanodine than that of the AGS group. Our results suggested that dependence of cardiac excitation-contraction coupling on calcium influx was weakened, while the function of sarcoplasmic reticulum as a source of activator Ca2+ was enhanced during hibernation, which might take an important part in the cold-tolerant adaptation of hibernating hearts.
Action Potentials↗
[The yak--the Asiatic mountain cattle in science and practice].
A total of 15 million yak is indigenous to central Asia (China, Mongolia, Nepal, India and Bhutan) on an area of 220 m hectares. The animal is a six purpose cattle, including milk production, meat production, wool production, leather production, capacity for work as draught, riding and transport animals and energy production via dried manure. Moreover, anatomical and physiological peculiarities of this high mountain cattle are presented which can tolerate cold temperatures of -50 degrees C. Finally, chances and limitations of crossbreeding yaks and indigenous cattle are discussed.
Animals↗
[Effect of low-dose recombinant humane erythropoietin therapy on the quality of life in patients with anemia in the course of end-stage renal failure treated with dialysis].
The aim of the study was to assess the efficacy of low-dose subcutaneous recombinant human erythropoietin (rHuEpo) therapy in hemodialysis patients with particular emphasis on their quality of life. Twenty five anemic (Ht25%) patients (14 males and 11 females, age 39-13 years) with end-stage renal disease were given rHuEpo (initial dose: 52.5 +/- 2.5 IU/kg/week; maintenance dose: 67.0-10.5 IU/kg/week) once or twice weekly for 12 months. Quality of life, assessed by self-administered questionnaire (1-3 scale), was measured every month. Additionally, sexual functions (-1 up to 3 scale, basal level 0), including libido and sexual satisfaction, and serum sex hormones (testosterone, LH, FSH, prolactin) were evaluated every 6 months. During first 4 months of the therapy there was a significant increase of Ht (21.1 +/- 0.5% vs 28.5 +/- 0.6%; p < 0.0001), which was maintained for the whole study period. From the 3rd month in majority of patients a marked (p < 0.01) improvement in their physical fitness, mood and cold tolerance was noted. Despite a substantial increase in sexual satisfaction (p < 0.01) and libido (p < 0.001), no significant changes in serum sex hormones profile, except transient rise in serum prolactin level, were observed. It is concluded that low-dose rHuEpo therapy for the renal anemia of hemodialysis patients is associated with a sustained significant improvement in their quality of life and sexual functions, despite no significant changes in sex hormones serum levels.
Adolescent↗
Assessment of liver function: pre- and peritransplant evaluation.
Liver transplantation has been demonstrated to be a successful therapeutic modality for patients with end-stage liver disease. The high rate of survival for an otherwise terminal condition has resulted in significant expansion of the indications and diseases treated by this procedure, and is hampered only by the limited numbers of organs available for transplantation. Efforts in clinical and laboratory medicine should be directed to identify candidates who would benefit most from this procedure, to provide better means for accurate assessment of liver reserve and the appropriate timing for transplantation, to identify quality liver grafts that would have the potential to tolerate cold preservation and reperfusion injury, and to assist in accurate monitoring of graft function immediately after transplantation. The aim of this manuscript is to describe the existing pathways for clinical and laboratory assessment of pretransplant residual liver function, the donor liver graft, and immediate posttransplantation function.
Humans↗
Rice genetic resources: history, conservation, investigative characterization and use in Japan.
Rice has been grown in Japan for about 3000 years. Although both japonica and indica varieties have been grown in Japan, now japonica rices are grown. Japanese rice breeding has used an ecological breeding approach. While emphasis in rice breeding in the 1940's and 1950's focussed on yield in recent decades quality has been of major importance. Consumer preference and name recognition of high quality varieties, such as Koshihikari, has resulted in slow acceptance of new varieties. Rice germplasm was systematically collected throughout Japan between 1962 and 1963. Subsequent acquisition and collecting, in Japan and other countries, has resulted in 28,000 accessions being conserved in the National Genebank, based at the National institute of Agrobiological Resources (NIAR). Research on genetic diversity of rice using a range of techniques, for example esterase isozymes, has revealed clinal variation in rice radiating from the center of diversity of rice in and around southwest China. Newly found genes in traditional rice germplasm, such as genes for non-elongating mesocotyl, are now routinely identified on the rice genome. Pioneering studies on eco-genetic differentiation of species in the genus Oryza in Japan has revealed much about the complex genepool for which rice evolved. Pest and disease resistance sources, particularly to blast, bacterial blight and brown plant hopper, from many countries have been incorporated into Japanese varieties. Cold tolerance at the booting stage was found in the Indonesian variety Silewah. In the future in characterisation of rice germplasm and interaction between rice germplasm specialists and rice molecular scientists, both in Japan and internationally, will be corner stones to securing rice genetic diversity and rice improvement in the next century.
Conservation of Natural Resources↗
Tolerance of altitude-acclimatized rats to exercise in the cold.
The tolerance of altitude-acclimatized (18,000 ft 4 wk) and unacclimatized rats to exercise at 5 degrees was determined. Fewer unacclimatized than acclimatized rats became fatigued during 9 hr of exercise in the cold. Normal body temperatures were maintained in both groups during 9 hr in the cold at rest, but after exercise unacclimatized rats became mildly hypothermic (body temperature 35 degrees) and acclimatized rats severely hypothermic (body temperature 27.9 degrees). Polycythemia (hematocrit 69) was produced during the altitude acclimatization. Altitude-acclimatized rats developed more severe hypoglycemia and lower liver glycogen and serum lactic acid concentrations after exercise than did controls. No pathological changes were found in resting altitude-acclimatized rats, but after exercise in the cold, a higher percentage of acclimatized than unacclimatized rats developed focal myocardial necrosis within 4 days. Reduced exercise tolerance is attributed to severe hypothermia with associated decreased metabolism, polycythemia, hypoglycemia, and a higher incidence of pathological changes in the cardiac and striated muscles.
Acclimatization↗
Differential and coordinated expression of Cbf and Cor/Lea genes during long-term cold acclimation in two wheat cultivars showing distinct levels of freezing tolerance.
The cold acclimation process in plants is primarily regulated through the signal transduction pathways that lead to the induction and enhancement of expression of different sets of Cor/Lea genes. Winter wheat 'Mironovskaya 808' (M808) exhibited a much higher level of freezing tolerance than spring wheat 'Chinese Spring' (CS), and the difference became clearer after the long-term cold acclimation. To understand the molecular basis of this cultivar difference, we isolated two CBF/DREB1 homologs, Wcbf2, which are the candidate gene for a transcription factor of the Cor/Lea genes. Expression of the Wcbf2 gene was induced rapidly by low temperature (LT) and drought but not by abscisic acid (ABA). The gene expression was temporal and at least twice up-regulated by LT. The first up-regulation occurred within 1-4 h, which might correspond to the rapid response to LT, while the second up-regulation occurred during 2-3 weeks of cold acclimation. After the second up-regulation, the amount of Wcbf2 transcript greatly decreased in CS, while it increased again in M808 after 4 weeks until 9 weeks (end of the test period). The maintenance of this high level of the Wcbf2 transcript might represent the long-term effect of cold acclimation. The activation of Cor/Lea genes followed the accumulation of Wcbf2 transcript suggested direct involvement of the Wcbf2 gene in the induction and enhancement of the Cor/Lea gene expression. The cultivar difference in freezing tolerance developed during different stages of cold acclimation can be at least partly explained by the differential and coordinated regulation of the predicted Cor/Lea gene signal transduction pathway that is mediated by the CBF/DREB1 transcription factors in common wheat.
Acclimatization↗
Effect of oral ketorolac and gender on human cold pressor pain tolerance.
1. Although the analgesic effect of opioids on experimental cold pressor (CP) pain has been well demonstrated, the analgesic effect of non-steroidal anti-inflammatory drugs (NSAIDs) on experimental CP pain has been less reliable, a finding complicated by inconsistencies in how CP analgesic effect is measured. 2. In the present study, a clinically relevant CP response of pain tolerance was used to assess the previously undescribed analgesic efficacy of the potent NSAID ketorolac (10 mg, p.o.), on CP pain across gender in a sample of normal subjects (n = 50). 3. Using a placebo-controlled crossover design, neither a main nor interaction effect for ketorolac on CP pain tolerance was detected. When examined by gender, male subjects exhibited a large placebo response to CP pain under study conditions, whereas women (albeit less pain tolerant at baseline) evidenced no placebo effect but a modest-to-good NSAID analgesic response. 4. Findings on the gender-specific placebo and analgesic NSAID response, integrated with the current literature, indicate that the lack of NSAID analgesic efficacy in the CP pain model may be related to unexamined and differential effects of how gender affects NSAID analgesic effect.
Administration, Oral↗