Strenuous exercise induces delayed-onset muscle damage including oxidative damage of cellular components. Oxidative stress to muscle cells impairs glucose uptake via disturbance of insulin signaling pathway. We investigated glucose uptake and insulin signaling in relation to oxidative protein modification in muscle after acute strenuous exercise. ICR mice were divided into sedentary and exercise groups. Mice in the exercise group performed downhill running exercise at 30 m/min for 30 min. At 24 hr after exercise, metabolic performance and insulin-signaling proteins in muscle tissues were examined. In whole body indirect calorimetry, carbohydrate utilization was decreased in the exercised mice along with reduction of the respiratory exchange ratio compared to the rested control mice. Insulin-stimulated uptake of 2-deoxy-[3 H]glucose in damaged muscle was decreased after acute exercise. Tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and phosphatidyl-3-kinase/Akt signaling were impaired by exercise, leading to inhibition of the membrane translocation of glucose transporter 4. We also found that acute exercise caused 4-hydroxy-nonenal modification of IRS-1 along with elevation of oxidative stress in muscle tissue. Impairment of insulin-induced glucose uptake into damaged muscle after strenuous exercise would be related to disturbance of insulin signal transduction by oxidative modification of IRS-1., W. Aoi ... [et al.]., and Obsahuje seznam literatury
Disturbance of capillary perfusions due to leukocyte adhesion, disseminated intravascular coagulat ion, tissue edema is critical components in the pathophysiology of sepsis. Alterations in brain microcirculation during sepsis are not clearly understood. The aim of this study is to gain an improved understanding of alterations through direct visualization of brain microcirculations in an experimental endotoxemi a using intravital microscopy (IVM). Endotoxemia was induced in Lewis rats with Lipopolysaccharide (LPS, 15 mg/kg i.v.). The dura mater was removed via a cranial window to expose the pial vessels on the brain surface. Using fluorescence dyes, plasma extravasation of pial venous vessels and leukocyte-endothelial interaction were visualized by intravital microscopy 4 h after LPS administration. Plasma cytokine levels of IL1-β, IL-6, IFN-γ, TNF-α and KC/GRO were evaluated after IVM. A sign ificant plasma extravasation of the pial venous vessels was found in endotoxemia rats compared to control animals. In addition , a significantly increased number of leukocytes adherent to the pial venous endothelium was observed in septic animals. Endotoxemia also induced a significant elevation of plasma cytokine levels of IL1-β, IL-6, IFN-γ, TNF-α and KC/GRO. Endotoxemia increased permeability in the brain pial vessels accompanied by an increase of leukocyte-endothelium interactions and an increase of inflammatory cytokines in the plasma., J. Zhou ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Spontaneous depolarization similar to that from the sinus node was documented from the myocardial sleeves of pulmonary veins (PV) after isolation procedures. It was then hypothesized that sinus node-like tissue is present in the PVs of humans. Based on a number of features, the myocar dium of myocardial sleeves (MS) is highly arrhythmogenic. Membrane potentials originating from MS are invariably recordable at the PVs ostia in patients with atrial fibrillation (AF) and delayed conduction around the PVs ostia may play a role in re-e ntry process responsible for the initiation and maintenance of AF. Diagnostic and therapeutic evidence of premature atrial beats induced in MS of PVs and resulting in launch of AF was detected by 3D electroanatomic method of monophasic action potential (MAP). MAP recording plays an important role in a di rect view of human myocardial electrophysiology under both physiological and pathological conditions. Its crucial importance lies in the fact that it enables the study of the action potential of myocardial cell in vivo and, therefore, the study of the dynamic relation of this potential with all the organism variables. The knowledge of pathological MAPs from PV myocardial sleeves can help us to confirm a diagnosis when finding the similar action potential morphology. MAP can be also used to evaluate the therap eutic efficiency of vagal nerves suppression, radiofrequency ablation or other treatment procedures in PVs myocardial sleeves as well as for post- treatment following up., O. Kittnar, S.-G. Yang, M. Mlček., and Obsahuje bibliografii a bibliografické odkazy
Monophasic action potential (MAP) can be recorded from the heart surface by optical method based on fluorescence measurement. The motion of isolated heart during experiment caused additional noise in recorded signal. The motion artifact can be eliminated by ratiometric fluorescence emission measurements. This study is based on experiments in which optical MAP measurement is done by single-wavelength and dualwavelength measurement of fluorescence emission. Both recording setups are presented and their advantages and disadvantages are discussed. MAPs recorded by both methods from isolated rabbit hearts perfused according to Langendorff are presented. Simultaneous electrograms (EG) and MAPs recording are analyzed and measurement of velocity of impulse conduction through heart tissue is presented., J. Kolářová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Acute lung injury in the preterm newborns can originate from prematurity of the lung and insufficient synthesis of pulmonary surfactant. This situation is known as respiratory distress syndrome (RDS). In the term neonates, the respiratory insufficiency is related to a secondary inactivation of the pulmonary surfactant, for instance, by action of endotoxins in bacterial pneumonia or by effects of aspirated meconium. The use of experimental models of the mentioned situations provides new information on the pathophy siology of these disorders and offers unique possibility to test novel therapeutic approaches in the conditions which are very similar to the clinical syndromes. Herewith we review the advantages and limitations of the use of experimental models of RDS and meconium aspiration syndrome (MAS) and their value for clinics., D. Mokra, A. Calkovska., and Obsahuje bibliografii
The first experimental model of atherosclerosis (in rabbits) is more than hundred years old. Several animal species have bee n used to produce hyperlipoproteine mia and possible atherosclerosis. The gene manipulation produced the most used models recently. This review acknowledges the extensive study of atherosclerotic changes in experimental models of hyperlipoprotein emia and at herosclerosis to come to light thus far and the purpose here is not only to summariz e the published data but also to try to add some details of our experience in using these models. In addition to rabbit (the old but also improved model by reno-vascular hy pertension) dog, birds, pig, hamster, mice, rat and non-human primate’s animal models are described. The gene manipulation produced the most used models two decades ago. Germline genetically engineered (without apoE or LDL receptor genes) animals have beco me the most used models producing atherosclerotic changes in the aorta. Recent new models also producing atherosclerotic changes but without germline genetic manipulation are also described., R. Poledne, L. Jurčíková-Novotná., and Obsahuje bibliografii
Sudden cardiac death defined as natural death from cardiac causes occurring within one hour of the onset of acute symptoms is one of the most significant non-injury causes of death in the adult population of industrialised countries. The understanding of the mechanisms leading to sudden cardiac death is so far limited. Recently, a number of experimental animal models with high incidence of sudden cardiac death were developed and are intensively studied to get new insights into the sudden cardiac death mechanisms. In this review the animal models of sudden cardiac death are summarized and their principal properties shortly described., M. Štengl., and Obsahuje bibliografii a bibliografické odkazy
a1_In the present study, the effect of the medial septal (MS) lesions on exploratory activity in the open field and the spatial and object recognition memory has been investigated. This experiment compares three types of MS lesions: electrolytic lesions that destroy cells and fibers of passage, neurotoxic -ibotenic acid lesions that spare fibers of passage but predominantly affect the septal noncholinergic neurons, and immunotoxin - 192 IgG -saporin infusions that only eliminate cholinergic neurons. The main results are: the MS electrolytic lesioned rats were impaired in habituat ing to the environment in the repeated spatial environment, but rats with immuno - or neurotoxic lesions of the MS did not differ from control ones; the MS electrolytic and ibotenic acid lesioned rats showed an increase in their exploratory activity to the objects and were impaired in habituating to the objects in the repeated spatial environment; rats with immunolesions of the MS did not differ from control rats; electrolytic lesions of the MS disrupt spatial recognition memory; rats with immuno - or neurotoxic lesions of the MS were normal in detecting spatial novelty; all of the MS - lesioned and control rats clearly reacted to the object novelty by exploring the new object more than familiar ones. Results observed across lesion techniques indicate that: (i) the deficits after nonselective damage of MS are limited to a subset of cognitive processes dependent on the hippocampus, (ii) MS is substantial for spatial, but not for object recognition memory - the object recognition memory can be supported outside the septohippocampal system; (iii) the selective loss of septohippocampal cholinergic or noncholinergic projections does not disrupt the function of the hippocampus to a sufficient extent to impair spatial recognition memory;, a2_(iv) there is dissociation between the two major components (cholinergic and noncholinergic) of the septohippocampal pathway in exploratory behavior assessed in the open field - the memory exhibited by decrements in exploration of repeated object presentations is affected by either electr olytic or ibotenic lesions, but not saporin., M. G. Dashniani, M. A. Burjanadze, T. L. Naneishvili, N. C. Chkhikvishvili, G. V. Beselia, L. B. Kruashvili, N. O. Pochkhidze, M. R. Chighladze., and Obsahuje bibliografii
It is known that psychostimulants including methamphetamine (MA) have neurotoxic effect, especially, if they are targeting CNS during its critical periods of development. The present study was aimed on evaluation of cognitive changes following scheduled prenatal MA exposure in combination with long-term exposure in adulthood of male rats. Two periods of gestation were targeted: 1st half - the embryonic day (ED) 1-11 and 2nd half - ED 12-22. Rat mothers received subcutaneously a daily injection of MA (5 mg/kg) or saline (SAL, 1 ml/kg) throughout scheduled periods. Male offspring were tested for cognitive changes in the Morris Water Maze (MWM) in adulthood. Each day of the experiment animals received an injection of MA (1 mg/kg) or SAL (1 ml/kg) during 12 days. Our results demonstrated that in the group of animals exposed to the drug during ED 1-11, neither prenatal MA exposure, nor adult MA treatment changed the performance in the MWM test. Only the velocity was increased in group with long-term MA treatment (SAL/MA and MA/MA). In the group of animals exposed to the drug during ED 12-22, rats exposed to MA prenatally and also in adulthood (MA/MA) swam faster but learned the position of the platform slower in the Place Navigation Test than animals exposed to SAL in adulthood (MA/SAL). In the Probe Test, MA/SAL had decreased velocity and swam shorter distance than MA/MA or SAL/SAL rats suggesting increased floating of these animals. In the Memory Retention Test, SAL/MA rats swam shorter distance than SAL/SAL or MA/MA animals suggesting changes in used strategies in memory recall. As conclusion, our results suggest differences in the effect of combination of prenatal and adult exposure to MA. These effects further depend on the stage of CNS development and schedule of MA exposure affecting intrauterine development in male rats., I. Hrebíčková, M. Malinová-Ševčíková, E. Macúchová, K. Nohejlová, R. Šlamberová., and Obsahuje bibliografii