BACKGROUND: Myocardial contractile dysfunction is often noticed without myocardial infarction, it may be due to myocardial stunning or hibernation. There are several case reports of myocardial stunning in patients with variant angina, but effect of recurrent myocardial spasm on myocardial contratile function in human is not well established. METHODS: To evaluate the effect of recurrent spasm-induced myocardial ischemia on myocardial contractile function, we analyzed the ejection fraction(by area-length method) and regional wall motion(by centerline method) at before and after intracoronary nitroglycerin in variant angina group and control group. Variant angina group consisted of 15 patients(LAD ; 10 patients, RCA ; 5 patients) and normal control group consisted of 6 patients. RESULTS: Ejection fraction increment after nitroglycerin infusion was not significant in normal control group, but that in variant angina group was significant(p<0.05). Pre-NG shortening fraction of LAD territory on both RAO and LAO view in patients with spasm in LAD was significantly lower than that in patients without spasm in LAD(RAO ; p<0.05, LAO ; p<0.01). On LAO view pre-NG shortening fraction of LAD territory in 6 patients with spasm and without significant fixed lesion was lower than that in patients without spasm in LAD(p<0.05). Shortening fraction increment after nitroglycerin infusion in LAD territory on both RAO and LAO view was significant in patients with spasm in LAD(RAO ; 0.05, LAO ; p<0.01), but that in LCX or RCA territory and that in LAD territory of patients without spasm in LAD was not significant. Shortening fraction increment after nitroglycerin infusion in RCA territory on LAO view was significant in patients with spasm in RCA(p<0.05), but that in LAD or LCX territory and that RCA territory of patients without spasm in RCA and was not significant. CONCLUSION: These observations suggest that recurrent coronary artery spasm results in reversible dysfunction of the ventricular global and regional contractility, and myocardial stunning may be the cause of this phenmenon.
Coronary Vessels* ; Hibernation ; Humans ; Myocardial Infarction ; Myocardial Ischemia ; Myocardial Stunning ; Nitroglycerin ; Spasm*

BACKGROUND: Reversibly dysfunctional myocardium caused by chronic reduction of coronary perfusion was named as hibernating myocardium. The clinical characteristics, however, was not well studied. METHOD: To observed the effects of revascularization on regional wall motion(RWM) abnormalities in patients with chronic ischemic heart disease, letf ventriculogram and dipyridamole stress Tl reinjection scan with reinjection imagine were done in 60 patients with angina or old myocardial infarction before and after PTCA. Subjects were divided into two groups, group A(21 patients, improved RWM after PTCA) and group B(39 patients, no change or aggravated RWM after PTCA). RESULTS: There were no significant differences in age and sex distribution between two group. Single vessel disease was more prevalent in group A (7/21, 33.3%) than in group B(1/39, 2.6%, p<0.05), and old myocardial infarction was more prevalent in group B(24/39, 61.5%) compared to group A(7/21, 33.3%, p<0.05). Reversible perfusion defects on Tl scan were found in 19 patients, 15 of whom(78.9%) showed improved RWM after PTCA. CONCLUSION: Hibernating myocardium was more prevalent in single vessel disease and angina patients. Sensitivity of Tl reinjection scan for detection of viable myocardium was 78.9%.
Coronary Artery Disease* ; Coronary Vessels* ; Dipyridamole ; Hibernation* ; Humans ; Myocardial Infarction ; Myocardial Ischemia ; Myocardium* ; Perfusion ; Sex Distribution

To investigate changes of glycoconjugates (GC) on the duodenal mucosa of Korean chipmunks (Tamias sibiricus) after cold-treatment, chipmunks were maintained in cold conditions (6 C) for 3, 5 or 9 months in an attempt to mimic conditions occurring during seasonal hibernation. Most chipmunks were active as before until 3 months in the cold room and since then were hibernated. Although there was significant decrease in neutral GC in cold-treated chipmunks compared with warm chipmunks, acid GC changed little. As for histochemical properties of acid GC in the duodenum, the cold-treated chipmunk showed some differences, such as appearance of villus goblet cells which contained the mixture of sulfated and nonsulfated GC. The affinities for all lectins used in this study were shown in the columnar cells of the duodenal villus and crypt, more intensive DBA, SBA, PNA, BSL-1, RCA-1 and sWGA affinities were demonstrated in the Golgi zone of columnar cells. These affinities decreased in the cold-treated groups, especially in the Golgi zone of columnar cells. The affinities with DBA, RCA-1, sWGA and BSL-1 was demonstrated in the goblet cells of the duodenum, but these affinities except DBA decreased in the cold-treated chipmunks. All lectin affinities except UEA-1 detected in duodenal gland, but cold-treatment induced a decrease of these affinities. The changes in amount and properties of GC in the present experimental model for hibernation may be due to the different intestinal environment associated with food intake. However, the present experimental model for hibernation, especially 9 months cold-treated chipmunks, stills need to be demonstrated during seasonal hibernation in the wild.
Duodenum ; Eating ; Glycoconjugates* ; Goblet Cells ; Hibernation ; Lectins ; Models, Theoretical ; Mucous Membrane* ; Sciuridae* ; Seasons

The present study was performed in order to test the effects of diphenylhydantoin (DPH) and two central nervous system (CNS) stimulants, intermittent light stimulation(ILS) and pentylenetetrazol (Metrazol) on body temperature (Tb) during cold exposure in the bat DHP delayed the onset of entry into hibernation in both the oriental discoloured bats and the little brown bats and formed long and prominent plateaus that were not found in the normal and the controls. The responses of body temperature to the ILS were sensitive and the body temperature fell dramatically in the big brown bats. Metrazol effects on body temperature were obvious but; seemed dose-dependent. The experimental results further support the hypothesis that hibernation is an epileptic fit as suggested by serveral researchers.
Animal ; Body Temperature/drug effects ; Body Temperature Regulation ; Chiroptera/physiology* ; Female ; Hibernation* ; Light ; Male ; Pentylenetetrazole/pharmacology ; Phenytoin/pharmacology

The potential for recovery of left ventricular dysfunction after myocardial revascularization represents a practical clinical definition for myocardial viability. The evaluation of viable myocardium in patients with severe global left ventricular dysfunction due to coronary artery disease and with regional dysfunction after acute myocardial infarction is an important issue whether left ventricular dysfunction may be reversible or irreversible after therapy. If the dysfunction is due to stunning or hibernation, functional improvement is observed. but stunned myocardium may recover of dysfunction with no revascularization. Hibernation is chronic process due to chronic reduction in the resting myocardial blood flow. There are two types of myocardial hibernation: "functional hibernation" with preserved contractile reserve and "structural hibernation" without contractile reserve in segments with preserved glucose metabolism. This review focus on the application of F-18 FDG and other radionuclides to evaluate myocardial viability. In addition the factors influencing predictive value of FDG imaging for evaluating viability and the different criteria for viability are also reviewed.
Coronary Artery Disease ; Glucose ; Hibernation ; Humans ; Metabolism ; Myocardial Infarction ; Myocardial Revascularization ; Myocardial Stunning ; Myocardium ; Radioisotopes ; Ventricular Dysfunction, Left

This is an in vitro study designed to assess the effect of temperature variation on the heart function of the five-strip eyebrow squirrel--amammal of the hibernating kind. A heart model of exsomatizing action and for determining the physiological parameters with four physiological recorders was used to measure the LVSP, LVEDP and (+/- dP/dtmax), respectively. It was found that the curves of the squirrel's heart mechanics property in relation to temperature variation are similar to the curves of the non-hibernating animals'. But, the squirrels' heart contraction function changes with in a much wider range, suggesting that their hearts are more tolerant of temperature variation.
Animals ; Biomechanical Phenomena ; Female ; Heart ; physiology ; Hibernation ; In Vitro Techniques ; Male ; Myocardial Contraction ; Sciuridae ; anatomy & histology ; physiology ; Temperature

Renal Na+, K+-activated adenosinetriphosphatase (Na-K-ATPase) activity and the p-aminohippurate (PAH) transport kinetics were studied in uninephrectomized rats and cold exposed hamsters. In rats, the specific activity of renal Na-K-ATPase increased by approximately 50% in one week after uninephrectomy and remained more or less constant during the next three weeks. The capacity (Jmax) of PAH influx into the renal cortical slice was sharply increased in one week after nephrectomy, but after which it returned to the control level. In cold exposed hamsters, the specific activity of renal Na-K-ATPase did not increase until 48 days of cold exposure at which time it reached approximately 50% above the control level. On the other hand, the Jmax of PAH influx increased by about 80% in 10 days of co1d exposure and somewhat declined thereafter. These results suggest that PAH active transport in the renal slice is not ratelimited by the activity of Na-K-ATPase under physiological conditions.
Aminohippuric Acids/metabolism* ; Animal ; Biological Transport, Active ; Female ; Hamsters ; Hibernation ; Kidney/enzymology* ; Male ; Na(+)-K(+)-Exchanging ATPase/metabolism* ; Nephrectomy ; Rats ; p-Aminohippuric Acid/metabolism*

PURPOSE: The purpose of this study was to clarify the effects of zinc treatment and hypothermia on visual adaptation and visual sensitivity in bullfrogs (Rana catesbeiana), which are poikilothermal animals capable of adjusting quickly to environmental temperature changes. METHODS: The effects of both zinc treatment and hypothermia on visual sensitivity were studied by using electroretinogram (ERG) recording and absorption spectra scanning before and after zinc and TSQ (N-[6-methoxy-8-quinolyl]-p-toluene sulfonamide) treatment, with or without temperature changes. RESULTS: In spite of malnutrition due to hibernation, the optimal zinc concentration effect was obtained at 10-4 M (10-2 M 200 microliter ZnCl2 in 20 microliter Ringer's solution) according to ERG recording. After zinc treatment and hypothermia induction, increments of all ERG components and thresholds were taken by ERG recording. These results showed that both zinc treatment and hypothermia may increase visual sensitivity during visual adaptation. In spectral scans, the absorbance increment due to zinc treatment and hypothermia was shown over the whole spectral range (400~750 nm), and it was especially prominent at alpha-peak (about 500 nm). In addition, there was a decrease in absorption differences between dark adaptation and light adaptation after zinc treatment. Furthermore, according to the visual sensitivity decrement using TSQ as a zinc specific chelator, this visual sensitivity increase was shown to be caused by zinc. CONCLUSIONS: As the results suggest, both zinc treatment and hypothermic effects may improve visual sensitivity by promoting rhodopsin regeneration and inhibiting rhodopsin bleaching induced by light illumination. Zinc may activate the enzyme activity of retinol dehydrogenase and phosphodiesterase, while hypothermic effects may improve precursor transport, which is required for rhodopsin regeneration, by tightening membrane adhesion between retinas and retinal pigment epithelia. In addition, we believe that zinc treatment and hypothermic effects may work synergistically to accelerate visual sensitivity during visual adaptation.
Absorption ; Adaptation, Ocular ; Animals ; Dark Adaptation* ; Hibernation ; Hypothermia ; Lighting ; Malnutrition ; Membranes ; Oxidoreductases ; Rana catesbeiana ; Regeneration ; Retina* ; Retinaldehyde ; Rhodopsin ; Vertebrates* ; Vitamin A ; Zinc*

The present study was conducted to explores the effects of short-term addition of 17β-E2 on the growth,gonad development and internal quality of overwintering Whitmania pigra. Before overwintering,0. 0,1. 0,10. 0,25. 0,50. 0,100. 0 μg·L~(-1) of 17β-E2 were added to the aquaculture water for 6 weeks and then hibernated for 60 days. The changes of growth performance,gonad index,morphological structure of spermary( ovary),endogenous steroid hormones level and internal quality were measured. The results showed that the body weight,weight gain rate,specific growth rate,female gonad index,oocyte development and endogenous estrogen level of the leech increased first and then decreased with the increase of the concentration of exogenous 17β-E2,which were higher than those of the control group. The body weight,weight gain rate and specific growth rate of the leech at the concentration of 25 μg·L~(-1)17β-E2 were significantly higher than those of the other groups( P<0. 05),oocyte development and endogenous estrogen levels were significantly higher than those of other groups at the concentration of 50 μg·L~(-1)( P<0. 05). When the concentration of exogenous 17β-E2 was higher than 50 μg·L~(-1),the levels of male gonad index,spermatocyte development,endogenous androgen and progesterone were significantly inhibited( P< 0. 05). There was no significant difference in endogenous corticosteroid levels among the groups. In conclusion,short-term addition of exogenous 17β-E2 of 10-25 μg·L~(-1) could promote the growth of overwintering leeches,oocyte development and antithrombin activity without inhibiting the development of male gonads.
Androgens ; analysis ; Animals ; Estradiol ; pharmacology ; Estrogens ; analysis ; Female ; Gonads ; drug effects ; growth & development ; Hibernation ; Leeches ; drug effects ; growth & development ; Male ; Progesterone ; analysis

Space traveling is imperative for mankind in the future. Expectedly, hibernation will become an option for space traveler to overcome the endless voyage. With regard to some of the studies pointed out that during hibernation, muscle will undergo atrophy and meantime neurogenesis will reduce, these obstacles were frequently related with stem cell regeneration. Thus, investigation on whether hibernation will lead to dysfunction of stem cell becomes an important issue. By going through four main systems in this article, such as, hematopoietic system, skeletal muscle system, central nervous system and orthopedic system, we are expecting that stem cells regeneration capacity will be affected by hibernation. To date, these researches are majorly the read-out from short term or seasonal hibernating mammals. Proposing and creating a simulated long-term hibernation animal model is turning essential for the further investigation on the effect of longer period of hibernation to human stem cells.
Adult Stem Cells ; Adult ; Arousal ; Atrophy ; Central Nervous System ; Hematopoietic System ; Hibernation ; Humans ; Mammals ; Models, Animal ; Muscle, Skeletal ; Neurogenesis ; Orthopedics ; Regeneration ; Seasons ; Stem Cells ; Torpor