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PubMed1982

[Annual cycle of the changes in the mitotic activity of gastric mucosal epithelium in hibernating rodents].

It was shown that mitotic activity of the gastric mucosa epithelium in Citelius erythrogenus Br. is characterized by pronounced seasonal changes. The highest mitotic index was recorded 3-4 days after the arousal from hibernation, while the lowest one during summer time (May-June). The mitoses are blocked during winter torpor. The circadian peak of the mitotic activity in summer was recorded at 10 p.m. The mitotic cells were discovered not only in the generative zone but also at all the levels of the fundal and pyloric glands. Radioautography with 3H-thymidine administration in vivo is not fit for studying the synthesis of DNA in sousliks.

Animals↗
PubMed1980

[Ultrastructural features of the gastric parietal cells of a hibernating rodent at different seasons of the year].

The structure of the parietal cells of the suslik Citellus erythrogenys Br. is similar to those in other animals and man and is determined by their localization along the gland. Hibernation, when active secretion of hydrochloric acid is absent, results in decreasing size of these cells, in sharply diminishing development of secretory structures and in alterations of the organoid structure; the number of lysosomes in the parietal cells also does not increase. After awakening, in the parietal cells a great amount of polysomes and cisterns of the granular cytoplasmic network is observed; they secure production of albuminous components in the cell structure. During 3-4 days the size of the cells increases considerably, as well as the level of development of tubulovesicles and intracellular secretory canaliculi. By the end of the first week after awakening, ultrastructure of the parietal cell is nearly identical to that of the animal in active state. Thus, seasonable changes in the ultrastructure of the parietal cells correspond to alterations occuring in the organism's vital activity.

Animals↗
PubMed1980

[Cyclic activity of adrenal function and seasonal variations of cortisol peripheral metabolism in a hibernating mammal, the hedgehog (Erinaceus europaeus L.) (author's transl)].

In the male hedgehog we have studied the nycthemeral and seasonal variations of plasma corticosteroids (cortisol and corticosterone) and different parameters (Half-life: t 1/2; apparent volume of distribution: VAD; Metabolic clearance rate: TCM; Production rate: TP) which characterize the metabolism of cortisol, the main corticosteroid in the hedgehog, and give and accurate representation of the cortico-adrenal gland activity. This study was done on unanesthetized animals, kept under natural climatic conditions and equipped with an arterial catheter which allowed blood to be sampled without visible disturbance. Plasma corticosteroids levels were measured at 4 h intervals over a period of 24 h, each month for one year. Monthly evolution of cortisol peripheral metabolism was studied on animals treated with dexamethasone, using a single injection of 3H-cortisol as a tracer after previous comparison with the continuous infusion technique. Plasma glucocorticosteroid levels show a marked nycthemeral rhythm from February to October : maximums are before sunset or during the first hours of the night and minimums are near sunrise. This nycthemeral cycle was not evident during November, December and January when the animals present many periods of torpor. The nycthemeral mean level of plasma corticosteroids (mean of 7 plasma sample concentrations determined over a period of 24 h) fluctuates during the year : corticosteroid levels are maximum in December, then decrease rapidly at the beginning of winter, stay at relatively low levels in spring and the increase which starts in summer becomes more pronounced in autumn. Cortisol peripheral metabolism shows large seasonal variations characterized by a strong reduction in autumn during hibernation, a large increase at the end of winter when the seasonal rhythm of locomotor activity is being restored, and then a gradual decrease in spring and summer which is interrupted by a brief increase in July. The seasonal change in corticoadrenal gland cortisol production rate is polyphasic and shows a maximum rise in autumn (December) and two other peaks which occur at the end of winter and in summer. In light of this it appears that in autumn and winter, the cortisol production rate and cortisol metabolic clearance rate are in opposite phase. The important changes observed during July (increases of t 1/2, VAD, TCM and TP) are probably connected to the metabolic preparation for the autumnal and winter rest.

Activity Cycles↗
PubMed1994

Laboratory rearing of a hibernating animal, pocket mouse (Perognathus flavus).

Hibernating pocket mice (Perognathus flavus) were obtained from the Department of Veterinary Medicine, Hokkaido University, in September 1990, and attempted to rear them in National Institute of Neuroscience, NCNP. Rearing of pocket mice was possible under the general conditions used for rearing mice. As a result of random mating of 4 females to 2 males for breeding, gestation was achieved in only one pair of animals, and parturition under artificial rearing conditions was observed for the first time. The animal gave birth to 3 offspring that had no body hair. Their eyes were closed. Each of the offspring weighed about 1.0g. The mean body weight of the females was 6.5g and that of males 5.6g at 3 weeks. Weaning was possible at this age. Subsequently the animals grew rapidly; the body weight was almost equal to that of an adult animal (8.0g) at 5 weeks of age for the females and 7 weeks for the males. The gestation period was estimated to be 26 days. These findings indicate that pocket mice can be bred and reared under general laboratory conditions.

Animal Husbandry↗
PubMed1995

Protein phosphorylation of synaptic membranes isolated from the brain of ground squirrels during hibernation.

In vitro protein phosphorylation of synaptic membranes isolated from neocortex and hippocampus of ground squirrels was studied. Three functional states of animals were investigated: torpid, awakened and active normothermic. Phosphorylation of a protein with a mol. wt of 53 kDa was independent on the functional state of the animals. Incorporation of 32P into this protein was greater in membranes of torpid and awakened squirrels than in membranes of active animals. These results suggest that protein phosphorylation is involved in the maintenance of membrane functions during hibernation.

Animals↗
PubMedDate not supplied

[The effect of short peptides isolated from the brain of a hibernating suslik on the rat EEG and behavior].

The intracerebroventricular injection of the peptides kyotorphin (KT), newkyotorphin (NKT), and Aps-Tyr (BS) changed rat behaviour. There was an increase in the rate of exploratory reactions, rearing, grooming, stereotypic scratching movements, yawning, stretching, hiccupping, sneezing. Similar effects had been earlier observed in rats after administration of the fraction (F, 1-10 kD) from the brain of hibernating ground squirrels in which the studied peptides were found. The EEG effects depended on a peptide dose. As in the case of F injection, KT in the dose of 4 mcg suppressed the theta- and alpha-rhythms, KT injection in the dose of 8 mcg produced similar effect within the first minutes. Then it was substituted for an enhancement of the delta-, theta-, and alpha-rhythms while the beta-activity was suppressed. The effects of BS (4 mcg) and KT (mcg) were similar, however, increase in the BS dose to 8 mcg resulted in an enhancement of the beta-activity as in the case of F injection. The NKT effects also consisted in delta-enhancement and beta-suppression, but, in contrast to KT, the theta- and alpha-suppression was short-term, delayed and occurred only after the peptide injection in the dose of 8 mcg.

Animals↗
PubMed1997

[The coiled bodies and satellite microbodies of the oocyte nuclei in hibernating Rana temporaria frogs contain actin].

Immunocytochemical analysis of preparation of dispersed nuclei content in oocytes of III-IV stages of oogenesis, in terms of Dumont (1972), from hibernating grass frogs using monoclonal antibodies against actin, revealed two types of intranuclear structures containing this protein: coiled bodies (CB) and satellite microbodies (SM). Staining of these preparations with Rhodamin-phalloidin, known specifically to interact with fibrillar actin, did not reveal it in these structures. Results of our biochemical studies, using protease ESP32 specifically cutting only globular actin, are suggesting that both CB and SM contain globular actin. Gall et al. (1975) proposed that CB may be involved in assembling and sorting of small nuclear RNA for the three main RNA processing pathways: pre-mRNA splicing, pre-rRNA processing, and histone pre-mRNA 3'-end formation. Our finding of actin in CB allows a suggestion on actin involvement in the transport of RNA processing complexes from CB to some actual places where processing of RNA takes place. According to our previous data (Tsvetkov, Parfenov., 1994), SM participate in the karyosphere capsule formation. This process is preceded by SM fusion triggered presumably by actin.

Actins↗
PubMedDate not supplied

[Redox properties of peptides potentially regulating animal hibernation].

Weak redox properties of peptides isolated from the brain of hibernating animals were determined in reactions with free radicals. The peptides Thr-Ser-Lys-Tyr-Arg (NKT) and Tyr-Arg diminished concentration of anion-radicals of dye excited by light, thus demonstrating electron-acceptor properties toward radicals. In contrast, the peptides Thr-Ser-Lys-Tyr (RZ-5) and Asp-Tyr acted as electron donors in the same radical reactions. The possible role of redox properties of these peptides in their regulation of Ca currents in excitable tissues is discussed.

Animals↗
PubMed1976

Effect of human chorionic gonadotropin on the testicular delta 5-3 beta-hydroxysteriod dehydrogenase and spermatogenesis in hibernating toad (Bufo melanostictus).

A histochemical study of testicular delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-OHD) and a quantitative study of seminiferous tubules in hibernating toad following the administration of HCG revealed stimulation in the activity of the enzyme delta 5-3 beta-OHD and the spermatogenesis by increasing spermiation, meiotic division and the maturation of secondary spermatogonia.

Animals↗
PubMed1976

Winter ecology of ectoparasites collected from hibernating Myotis velifer (Allen) in southwestern Oklahoma (Chiroptera: Vespertilionidae.

During the winter of 1971-72, Trichobius major, T, corynorhini, Mydopsylla collinsi, Macronyssus crosbyi, M. unidens, Paraspinturnix globosus, Spinturnix carloshoffmani, Ornithodoros sp., Albeckia senase, Nycteriglyphus sp. A, and Olabidocarpus sp. were quantitatively collected from hibernating Myotis velifer, Plecotus townsendii, and Pipistrellus subflavus. Significantly greater numbers of S. carloshoffmani and M. crosbyi were found on female M. velifer, while greater numbers of P. globosus were found on males. With the exception of T. major and P. globosus which were radomly distributed, all ectoparasites exhibited a contagious distribution on M. velifer. Only T. major and S. carloshoffmani had a 1:1 sex ratio, the remaining species had significantly fewer males. M. unidens, M. crosbyi, and N. species A were positively associated, while M. collinsi was negatively associated with both Macronyssus; the remaining species were not signficantly associated. With the exception of T. major and P. globosus, ectoparasite densities decreased during the winter.

Animals↗
PubMedDate not supplied

[The myoglobin level in skeletal muscles of the hibernating Iakutiia ground squirrel Citellus undulatus].

Many characteristics of the ground squirrel metmyoglobin (Mb) were found to be similar to those of the pig and different from the whale ones. The Mb content in winter time was 2.5-3.0-fold higher in hibernating and arousing ground squirrels than in alert ones. This seems to be connected with the high demand of oxygen in the muscles at the first stage of arousal.

Animals↗
PubMed1992

Presurgical identification of hibernating myocardium by combined use of technetium-99m hexakis 2-methoxyisobutylisonitrile single photon emission tomography and fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography in patients with coronary artery disease.

We tested the possibility of identifying areas of hibernating myocardium by the combined assessment of perfusion and metabolism using single photon emission tomography (SPET) with technetium-99m hexakis 2-methoxyisobutylisonitrile (99mTc-MIBI) and positron emission tomography (PET) with fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG). Segmental wall motion, perfusion and 18F-FDG uptake were scored in 5 segments in 14 patients with coronary artery disease (CAD), for a total number of 70 segments. Each subject underwent the following studies prior to and following coronary artery bypass grafting (CABG): first-pass radionuclide angiography, electrocardiography gated planar perfusion scintigraphy and SPET perfusion scintigraphy with 99mTc-MIBI and, after 16 h fasting, 18F-FDG/PET metabolic scintigraphy. Wall motion impairment was either decreased or completely reversed by CABG in 95% of the asynergic segments which exhibited 18F-FDG uptake, whereas it was unmodified in 80% of the asynergic segments with no 18F-FDG uptake. A stepwise multiple logistic analysis was carried out on the asynergic segments to estimate the postoperative probability of wall motion improvement on the basis of the preoperative regional perfusion and metabolic scores. The segments with the highest probability (96%) of functional recovery from preoperative asynergy after revascularization were those with a marked 18F-FDG uptake prior to CABG. High probabilities of functional recovery were also estimated for the segments presenting with moderate and low 18F-FDG uptake (92% and 79%, respectively). A low probability of functional recovery (13%) was estimated in the segments with no 18F-FDG uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Artery Bypass↗
PubMed1977

Thermosensitivity of preoptic neurones in a hibernator at high and low ambient temperatures.

The effect of ambient temperature on the thermosensitivity of preoptic neurones was studied in euthermic golden hamsters. At skin temperatures (Tsk) of 20 degrees C, preoptic units were still responsive to hypothalamic temperatures (Thy) below 10 degrees C, while at Tsk = 36 degrees C these neurones became inactive at Thy = 15 degrees C on the average. These studies suggest that thermoreceptive preoptic neurones, influenced by a high activity of cutaneous cold-receptors, are capable of sensing core temperatures even in deep hibernation.

Animals↗
PubMed1996

The clinical impact of thallium-201 reinjection for the detection of myocardial hibernation.

Thallium-201 reinjection improves detection of hibernating myocardium in about 30%-50% of persisting defects. The main goal of cardiac revascularization techniques is amelioration of clinical symptoms such as angina and dyspnoea; however, improvement in regional and global pump function is an additional and important target. The aim of this study was to investigate whether fill-in in the reinjection study is correlated with improved contractile function after treatment (percutaneous transluminal coronary angioplasty/aortocoronary bypass surgery). We studied 32 patients with coronary heart disease and impaired regional wall motion (RWM). RWM and ejection fraction (EF) were assessed by analysing ventriculographic images using the centreline method (values in standard deviations from mean values found in a healthy control group). Three 201Tl single-photon emission tomographic studies (stress, redistribution and reinjection) were performed prior to revascularization and analysed using a bull s-eye scheme. Patients were divided into two groups (group FI-=no fill-in, n=16; group FI+=fill-in, n=16). Fifty-six percent of all patients showed persisting defects, and 56% of these defects showed fill-in after reinjection. Fill-in in our patient group was independent of the size of the persisting defects. After revascularization RWM increased significantly in group FI+ (from -1.9 to 0.0 SD, P<0.001) whereas group FI- showed no significant change (from -1.6 to -1.8 SD). EF increased from -4.3 preoperatively to -2.1 SD postoperatively in group FI+ and did not change significantly in group FI- (-2.5 to -3.2 SD). The predictive value of reinjection for improvement of RWM was 88%. It is concluded that fill-in in the 201Tl reinjection image can predict recovery of RWM and EF after revascularization and should be used in all patients with impaired RWM and persisting defects independent of their extent.

Adult↗
PubMed2003

Pathophysiology and diagnosis of hibernating myocardium in patients with post-ischemic heart failure: the contribution of PET.

Identification and treatment of hibernating myocardium (HM) lead to improvement in LV function and prognosis in patients with post-ischemic heart failure. Different techniques are used to diagnose HM: echocardiography, MRI, SPECT and PET and, in patients with moderate LV impairment, their predictive values are similar. There are few data on patients with severe LV dysfunction and heart failure in whom the greatest benefits are apparent after revascularization. Quantification of FDG uptake with PET during hyperinsulinemic euglycemic clamp is accurate in these patients with the greatest mortality risk in whom other techniques may give high false negative rates. The debate on whether resting myocardial blood flow to HM is reduced or not has stimulated new research on heart failure in patients with coronary artery disease. PET with H2(15)O or 13NH3 has been used for the absolute quantification of regional blood flow in human HM. When HM is properly identified, resting blood flow is not different from that in healthy volunteers although a reduction of approximately 20% can be demonstrated in a minority of cases. PET studies have shown that the main feature of HM is a severe impairment of coronary vasodilator reserve that improves after revascularization in parallel with LV function. Thus, the pathophysiology of HM is more complex than initially postulated. The recent evidence that repetitive ischemia in patients can be cumulative and lead to more severe and prolonged stunning, lends further support to the hypothesis that, at least initially, stunning and HM are two facets of the same coin.

Blood Flow Velocity↗
PubMed2005

DADLE induces a reversible hibernation-like state in HeLa cells.

[D-Ala(2)-D-Leu(5)-Enkephalin] (DADLE) can induce hibernation when injected into ground squirrels in summer and is able to increase the survival time of explanted organs such as liver and lung. Since cell metabolism is a target of this peptide, we have treated HeLa cells with DADLE and investigated its possible effect on transcription and proliferation as well as the resumption of metabolic activity after treatment. The labelling for Pol I, Pol II and for splicing factors such as snRNPs and SC-35 decreased after treatment as did the nucleolar labelling for UBF. In treated cells, several spherical nuclear bodies were found to be labelled for hnRNPs. In parallel, the number of proliferating cells decreased after treatment with DADLE. After recovery, there was a gradual resumption of cell function: transcription and splicing factors had a distribution similar to that of controls; proliferation resumed; nuclear bodies, representing storage sites for RNPs, disappeared.

Antimetabolites↗
PubMed2006

Reduced sarcoplasmic reticulum Ca2+ -ATPase activity and dephosphorylated phospholamban contribute to contractile dysfunction in human hibernating myocardium.

Human hibernating myocardium (HHM) is characterized by reversible contractile dysfunction during chronic ischemia. A disturbed calcium-homeostasis is a decisive factor for reduced functional capacity in heart diseases. We therefore investigated calcium-handling proteins in HHM. In 12 patients suffering from multi-vessel coronary artery disease and contractile dysfunction with indication for bypass surgery, HHM was detected preoperatively by thallium scintigraphy, radionuclide ventriculography and dobutamine echocardiography. Transmural biopsies of these regions were taken and analyzed by immunohistochemistry and electron microscopy. Furthermore, SR-calcium ATPase (SERCA2a), phospholamban (PLN), the phosphorylated forms of PLN (PLN-Ser16, PLN-Thr17) as well as sodium-calcium exchanger (NCX) and ryanodine receptor (RyR2) were investigated by RT-PCR and Western-blotting. Additionally, SERCA2a activity was measured by an enzyme-coupled assay. In all patients complete functional recovery could be documented 3 months after revascularization by repeating all preoperative investigations. In HHM maximal SERCA2a activity was significantly reduced (HHM: 424.5 +/- 33.9, control: 609.0 +/- 48.5 nmol ATP mg protein(-1) min(-1), p <or= 0.05), whereas SERCA2a protein levels were unchanged. mRNA levels (HHM: 1.36 +/- 0.08 vs. control: 0.78 +/- 0.04, p <or= 0.05) and protein amount (HHM:1.67 +/- 0.14 vs. control: 1.00 +/- 0.04, p <or= 0.05) of PLN (A1) were increased resulting in an increased PLN:SERCA2a-ratio. PLN-Ser16 (HHM: 0.60 +/- 0.08 vs. control: 1.00 +/- 0.11, p <or= 0.05) and PLN-Thr17 (HHM: 0.63 +/- 0.11 vs. control: 1.00 +/- 0.06, p <or= 0.05) phosphorylation was significantly decreased. RyR2 and NCX showed no significant alteration. In HHM a decreased activity of SERCA2a due to an impaired phosphorylation of PLN contributes to contractile dysfunction. The increase in the relative ratio of PLN/SERCA2a leads to a decreased calcium affinity of SERCA2a.

Aged↗