Peritoneal dialysis (PD) is a well established method of depuration in uremic patients. Standard dialysis solutions currently in use are not biocompatible with the peritoneal membrane. Studying effects of dialysate on peritoneal membrane in humans is still a challenge. There is no consensus on the ideal experimental model so far. We, therefore, wanted to develop a new experimental non-uremic rabbit model of peritoneal dialysis, which would be practical, easy to conduct, not too costly, and convenient to investigate the long-term effect of dialysis fluids. The study was done on 17 healthy Chinchilla male and female rabbits, anesthetized with Thiopental in a dose of 0.5 mg/kg body mass. A catheter, specially made from Tro-soluset (Troge Medical GMBH, Hamburg, Germany) infusion system, was then surgically inserted and tunneled from animals' abdomen to their neck. The planned experimental procedure was 4 weeks of peritoneal dialysate instillation. The presented non-uremic rabbit model of peritoneal dialysis is relatively inexpensive, does not require sophisticated technology and was well tolerated by the animals. Complications such as peritonitis, dialysis fluid leakage, constipation and catheter obstruction were negligible. This model is reproducible and can be used to analyze the effects of different dialysis solutions on the rabbit peritoneal membrane., S. Zunic-Bozinovski, Z. Lausevic, S. Krstic, N. Jovanovic, J. Trbojevic-Stankovic, B. Stojimirovic., and Obsahuje bibliografii a bibliografické odkazy
Senile dementia of Alzheimer´s type (AD) is commonly characterized as a neurodegenerative disorder, which exhibits gradual changes of consciousness, loss of memory, perception and orientation as well as loss of personality and intellect. AD prevalence increases dramatically with age and is the fourth cause of death in Europe and in the USA. Currently, there are no available biological markers, which gives clinicians no other alternative than to rely upon clinical diagnosis by exclusion. There is no assay of objective ante mortem biochemical phenomena that relate to the pathophysiology of this disease. The pathophysiology of AD is connected with alterations in neurotransmission, plaque formation, cytoskeletal abnormalities and disturbances of calcium homeostasis. The search for a test, which is non-invasive, simple, cheap and user-friendly, should be directed at accessible body fluids. Only abnormalities replicated in large series across different laboratories fulfilling the criteria for a biological marker are likely to be of relevance in diagnosing AD. To date, only the combination of cerebrospinal fluid t and Ab42 most closely approximate an ideal biomarker of Alzheimer´s disease. A short review on the role of biological markers in AD on the basis of the literature, contemporary knowledge and our own recent findings are presented., D. Řípová, A. Strunecká., and Obsahuje bibliografii
Cortisol is secreted by the central hypothalamo-pituitary-adrenal axis and affects many target organs and tissues, particularly in response to stressor demands and infection. Recent data reporting cortisol synthesis in hair follicles have shown the existence of a parallel “peripheral” HPA-axis. However, although there is evidence from in vitro studies and single-observation comparisons between groups that cortisol from hair follicles reflects endocrine changes associated with stressor demands, there are no reports to date of repeated measurements of in vivo cortisol responsivity in hair to transitory stressors. This issue was investigated with three males who underwent 1 min cold pressor test (CP). Cortisol response in hair to stressor demand appears to be (a) swift but transitory, (b) localized to the site of the demand and (c) independent of central HPA-axis activity., C. F. Sharpley, K. G. Kauter, J. R. McFarlane., and Obsahuje seznam literatury
The hormone leptin, which is thought to be primarily produced by adipose tissue, is a polypeptide that was initially characterized by its ability to regulate food intake and energy metabolism. Leptin appears to signal the status of body energy stores to the brain, resulting in the regulation of food intake and whole-body energy expenditure. Subsequently, it was recognized as a cytokine with a wide range of peripheral actions and is involved in the regulation of a number of physiological systems including reproduction. In the fed state, leptin circulates in the plasma in proportion to body adiposity in all species studied to date. However other factors such as sex, age, body mass index (BMI), sex steroids and pregnancy may also affect leptin levels in plasma. In pregnant mice and humans, the placenta is also a major site of leptin expression. Leptin circulates in biological fluids both as free protein and in a form that is bound to the soluble isoform of its receptor or other binding proteins such as one of the immunoglobulin superfamily members Siglec-6 (OBBP1). Although the actions of leptin in the control of reproductive function are thought to be exerted mainly via the hypothalamicpituitary-gonadal axis, there have also been reports of local direct effects of leptin at the peripheral level, however, these data appear contradictory. Therefore, there is a need to summarize the current status of research outcomes and analyze the possible reasons for differing results and thus provide researchers with new insight in designing experiments to investigate leptin effect on reproduction. Most importantly, our recent experimental data suggesting that reproductive performance is improved by decreasing concentrations of peripheral leptin was unexpected and cannot be explained by hypotheses drawn from the experiments of excessive exogenous leptin administration to normal animals or ob/ob mice., M. Herrid, S. K. A. Palanisamy, U. A. Ciller, R. Fan, P. Moens, N. A. Smart, J. R. McFarlane., and Obsahuje bibliografii
a1_Using magnetic resonance imaging (MRI) in conjunction with synchronized spirometry we an alyzed and compared diaphragm movement during tidal breathing and voluntary movement of the diaphragm while breath holding. Breathing cycles of 16 healthy subjects were examined using a dynamic sequence (77 slices in sagittal plane during 20 s, 1NSA, 240x256, TR4.48, TE2.24, FA90, TSE1, FOV 328). The amplitude of movement of the apex and dorsal costophren ic angle of the diaphragm were measured for two test conditions: tidal breathing and voluntary breath holding. The maximal inferior and superior positions of the diaphragm were subtracted from the corresponding positions during voluntary movements while breath holding. The average amplitude of inferio-superior mo vement of the diaphragm apex during tidal breathing was 27.3±10.2 mm (mean ± SD), and during voluntary movement while breath holding was 32.5±16.2 mm. Movement of the costophrenic angle was 39±17.6 mm during tidal breathing and 45.5±21.2 mm during voluntary movement while breath holding. The inferior position of the diaphragm was lower in 11 of 16 subjects (68.75 %) and identical in 2 of 16 (12.5 %) subj ects during voluntary movement compared to the breath holding. Pearson’s correlation coefficient was used to demonstrate that movement of the costophrenic angle and apex of the diaphragm ha d a linear relationship in both examined situations (r=0.876). A correlation was found between the amplitude of diaphragm movement during tidal breathing and lung volume (r=0.876). The amplitude of movement of the diaphragm with or without breathing showed no correlation to each other (r=0.074). The moveme nt during tidal breathing shows a correlation with the changes in lung volumes. Dynamic MRI demonstrated that individuals are capable of moving their diaphragm voluntarily, but the amplitude of movement differs from person to person., a2_In this study, the movements of the diaphragm apex and the costophr enic angle were synchronous during voluntary movement of the diaphragm while breath holding. Although the sample is small, this study confirms that the function of the diaphragm is not only respiratory but also postural and can be voluntarily controlled., P. Kolář, J. Neuwirth, J. Šanda, V. Suchánek, Z. Svatá, J. Volejník, M. Pivec., and Obsahuje bibliografii
There are three basic procedures used for an assessment of the electrical heart field from the body surface: standard electrocardiography, vectorcardiography, and body surface potential mapping (BSPM). BSPM has two major advantages over both other methods: 1) it allows exploring the entire chest surface, thus providing all the information on the cardiac electric field available at the body surface; 2) it is more sensitive in detecting local electrical events, such as local conduction disturbances or regional heterogeneities of ventricular recovery. Nevertheless the results obtained using BSPM procedure cannot answer all questions about real causality of detected changes of the electrical heart field. We tried therefore to use mathematical model of the electrical field in order to answer these questions. A simple and anatomical forward calculation model was used to test the hypothesis whether the altered position of the heart could explain heterogeneity of repolarization at late stages of pregnancy in humans. The hypothesis was declined. Further findings included: A. Repolarization duration (represented by QT interval) in healthy subjects are distributed regularly and predictably on the body surface carrying no information about local pathology. B. At any systemic analysis of ventricular repolarization, it is vital to consider the regions where any electrode systems record low amplitudes due to methodological, not pathological reasons. C. Anatomical (heterogeneous) model did not yield superior results over simple (homogenous) ones possibly since none reflected the specific torso geometry of individual patients., O. Kittnar, M. Mlček., and Obsahuje bibliografii a bibliografické odkazy
Anemia frequently complicates chronic kidney disease (CKD). We investigated here the effect of adenine-induced CKD in rats on erythrocyte count (EC), hematocrit (PCV) and hemoglobin (Hb) concentration, as well as on the activity of L-γ-glutamyl transferase (GGT) and the concentrations of iron (Fe), transferrin (Tf), ferritin (F), total iron binding capacity (TIBC) / unsaturated iron binding capacity (UIBC) and hepcidin (Hp) in serum and erythropoietin (Epo) in renal tissue. Renal damage was assessed histopathologically, and also by measuring the serum concentrations of the uremic toxin indoxyl sulfate (IS), creatinine, and urea, and by creatinine clearance. We also assessed the influence of concomitant treatment with gum acacia (GA) on the above analytes. Adenine feeding induced CKD, accompanied by significant decreases (P<0.05) in EC, PCV, and Hb, and in the serum concentrations of Fe, Tf, TIBC, UIBC and Epo. It also increased Hp and F levels. GA significantly ameliorated these changes in rats with CKD. A general improvement in the renal status of rats with CKD after GA is shown due to its antiinflammatory and anti-oxidant actions, and reduction of the uremic toxin IS, which is known to suppress Epo production, and this may be a reason for its ameliorative actions on the indices of anemia studied., B. H. Ali, M. Al Za'Abi, A. Ramkumar, J. Yasin, A. Nemmar., and Obsahuje bibliografii
Hemolytic uremic syndrome (HUS) is a type of thrombotic microangiopathy, in the course of which some patients may develop chronic kidney disease (CKD). It is clinically important to investigate the markers of a poor prognosis. The levels of angiotensinogen (AGT) and interleukin-18 (IL-18) in serum and urine were evaluated. Study was conducted in 29 children with a history of HUS. Serum and urine AGT concentration was significantly higher in children after HUS as compared to the control group. No differences depending on the type of HUS and gender were noted. The serum concentration of IL-18 in children after HUS was significantly lower, whereas in urine did not differ significantly between the sick and healthy children. A negative correlation between the concentration of AGT in serum and albuminuria in patients after HUS was detected. The results indicate that the concentration of AGT in serum and urine in children after HUS increases, which may indicate the activation of the intrarenal renin-angiotensin-aldosterone system. The statement, that AGT may be a good biomarker of CKD after acute kidney injury due to HUS requires prospective studies with follow-up from the acute phase of the disease on a larger group of patients. Reduced IL-18 serum concentration in children after HUS with no difference in its urine concentration may indicate a loss of the protective effects of this cytokine on renal function due to previously occurred HUS., K. Lipiec, P. Adamczyk, E. Świętochowska, K. Ziora, M. Szczepańska., and Obsahuje bibliografii
Exercise training-induced cardiac hypertrophy occurs following a program of aerobic endurance exercise training and it is considered as a physiologically beneficial adaptation. To investigate the underlying biology of physiological hypertrophy, we rely on robust experimental models of exercise training in laboratory animals that mimic the training response in humans. A number of experimental strategies have been established, such as treadmill and voluntary wheel running and swim training models that all associate with cardiac growth. These approaches have been applied to numerous animal models with various backgrounds. However, important differences exist between these experimental approaches, which may affect the interpretation of the results. Here, we review the various approaches that have been used to experimentally study exercise training-induced cardiac hypertrophy; including the advantages and disadvantages of the various models., Y. Wang, U. Wisloff, O. J. Kemi., and Obsahuje bibliografii a bibliografické odkazy