The maintenance of plasma sodium concentration within a narrow limit is crucial to life. When it differs from normal physiological patterns, several mechanisms are activated in order to restore body fluid homeostasis. Such mechanisms may be vegetative and/or behavioral, and several regions of the central nervous system (CNS) are involved in their triggering. Some of these are responsible for sensory pathways that per ceive a disturbance of the body fluid homeostasis and transmit information to other regions. These regions, in turn, initiate adequate adjustments in order to restore homeostasis. The main cardiovascular and autonomic responses to a change in plasma sodium concentration are: i) changes in arterial blood pressure and heart rate; ii) changes in sympathetic activity to the renal system in order to ensure adequate renal sodium excretion/absorption, and iii) the secretion of compounds involved in sodium ion home ostasis (ANP, Ang-II, and ADH, for example). Due to their cardiovascular effects, hypertonic saline solutions have been used to promote resuscitation in hemorrhagic patients, thereby increasing survival rates following trauma. In the present review, we exp ose and discuss the role of several CNS regions involved in body fluid homeostasis and the effects of acute and chronic hyperosmotic challenges., M. C. Dos Santos Moreira, L. M. Naves, S. M. Marques, E. F. Silva, A. C. S. Rebelo, E. Colombari, G. R. Pedrino., and Obsahuje bibliografii
Olfaction enables most mammalian species to detect and discriminate vast numbers of chemical structures called odorants and pheromones. The perception of such chemical compounds is mediated via two major olfactory systems, the main olfactory system and the vomeronasal system, as well as minor systems, such as the septal organ and the Grueneberg ganglion. Distinct differences exist not only among species but also among individuals in terms of their olfactory sensitivity; however, little is known about the mechanisms that determine these differences. In research on the olfactory sensitivity of mammals, scientists thus depend in most cases on behavioral testing. In this article, we reviewed scientific studies performed on various mammalian species using different methodologies and target chemical substances. Human and non-human primates as well as rodents and dogs are the most frequently studied species. Olfactory threshold studies on other species do not exist with the exception of domestic pigs. Olfactory testing performed on seals, elephants, and bats focused more on discriminative abilities than on sensitivity. An overview of olfactory sensitivity studies as well as olfactory detection ability in most studied mammalian species is presented here, focusing on comparable olfactory detection thresholds. The basics of olfactory perception and olfactory sensitivity factors are also described., M. Wackermannová, L. Pinc, L. Jebavý., and Obsahuje bibliografii
Spontaneously Diabetic Torii (SDT) fatty rats, a new obese diabetic model, reportedly presented with features of non-alcoholic steatohepatitis (NASH) after 32 weeks of age. We tried to accelerate the onset of NASH in SDT fatty rats using dietary cholesterol loading and noticed changes in the blood choline level which is expected to be a NASH biomarker. Body weight and biochemical parameters were measured from 8 to 24 weeks of age. At 16, 20, 24 weeks, pathophysiological analysis of the livers were performed. Hepatic lipids, lipid peroxides, and the expression of mRNA related to triglyceride (TG) synthesis, inflammation, and fibrosis were evaluated at 24 weeks. Hepatic fibrosis was observed in SDT fatty rats fed cholesterol-enriched diets (SDT fatty-Cho) from 16 weeks. Furthermore, hepatic lipids and lipid peroxide were significantly higher in SDT fatty-Cho than SDT fatty rats fed normal diets at 24 weeks. Hepatic mRNA expression related to TG secretion decreased in SDT fatty-Cho, and the mRNA expression related to inflammation and fibrosis increased in SDT fatty-Cho at 24 weeks. Furthermore, SDT fatty-Cho presented with increased plasma choline, similar to human NASH. There were no significant changes in the effects of feeding a cholesterol-enriched diet in Sprague-Dawley rats. SDT fatty-Cho has the potential to become a valuable animal model for NASH associated with type 2 diabetes and obesity., Y. Toriniwa, M. Muramatsu, Y. Ishii, E. Riya, K. Miyajima, S. Ohshida, K. Kitatani, S. Takekoshi, T. Matsui, S. Kume, T. Yamada, T. Ohta., and Obsahuje bibliografii
In as early as 1997, the World Health Organization officially recognized obesity as a chronic disease. The current epidemic of obesity and overweightness has aroused great interest in the study of adipose tissue formation. The transcription factor peroxisome proliferator-activated receptor γ (PPARγ) binds to the target gene promoter regulatory sequences, acting as a key factor in regulating the differentiation of preadipocytes in the adipose tissue, and plays an important role in regulating the adipocyte metabolism. A further understanding of the structure and expression characteristics of PPARγ, in addition to its mechanisms of action in adipocyte differentiation, may be applied to control obesity and prevent obesity-related diseases. In this article, recent studies investigating the effect of regulating PPARγ on adipocyte differentiation are reviewed. In particular, the structural characteristics, expression patterns, and molecular mechanisms of PPARγ function in adipocyte differentiation are considered., Hui Wu, Xiaohua Li, Chunyan Shen., and Obsahuje bibliografii
Fibroblast growth factor (FGF) signaling plays an important role during embryonic induction and patterning, as well as in modulating proliferative and hypertrophic growth in fetal and adult organs. Hemodynamically induced stretching is a powerful physiological stimulus for embryonic myocyte proliferation. The aim of this study was to assess the effect of FGF2 signaling on growth and vascularization of chick embryonic ventricular wall and its involvement in transmission of mechanical stretchinduced signaling to myocyte growth in vivo . Myocyte proliferation was significantly higher at the 48 h sampling interval in pressure-overloaded hearts. Neither Western blotting, nor immunohistochemistry performed on serial paraffin sections revealed any changes in the amount of myocardial FGF2 at that time point. ELISA showed a significant increase of FGF2 in the serum. Increased amount of FGF2 mRNA in the heart was confirmed by real time PCR. Blocking of FGF signaling by SU5402 led to decreased myocyte proliferation, hemorrhages in the areas of developing vasculature in epicardium and digit tips. FGF2 synthesis is increased in embryonic ventricular cardiomyocytes in response to increased stretch due to pressure overload. Inhibition of FGF signaling impacts also vasculogenesis, pointing to partial functional redundancy in paracrine control of cell proliferation in the developing heart., E. Krejci, Z. Pesevski, O. Nanka, D. Sedmera., and Obsahuje bibliografii
Nitric oxide (NO) is an important endogenous neurotransmitter and mediator. It participates in regulation of physiological processes in different organ systems including airways. Therefore, it is important to clarify its role in the regulation of both airway and vascular smooth muscle, neurotransmission and neurotoxicity, mucus transport, lung development and in the surfactant production. The bioactivity of NO is highly variable and depends on many factors: the presence and activity of NO-producing enzymes, activity of competitive enzymes (e.g. arginase), the amount of substrate for the NO production, the presence of reactive oxygen species and others. All of these can change NO primary physiological role into potentially harmful. The borderline between them is very fragile and in many cases not entirely clear. For this reason, the research focuses on a comprehensive understanding of NO synthesis and its metabolic pathways, genetic polymorphisms of NO synthesizing enzymes and related effects. Research is also motivated by frequent use of exhaled NO monitoring in the clinical manifestations of respiratory diseases. The review focuses on the latest knowledge about the production and function of this mediator and understanding the basic physiological processes in the airways., M. Antosova, D. Mokra, L. Pepucha, J. Plevkova, T. Buday, M. Sterusky, A. Bencova., and Obsahuje bibliografii
Idiopathic pes equinovarus (clubfoot) is a congenital deformity of the foot and lower leg defined as a fixation of the foot in plantar flexion, adduction, supination and varus. The deformity does not affect only the foot position, which is usually investigated by radiography, CT, micro-CT, MRI or ultrasound but logically influence the whole gait biomechanics. It is supposed, that clubfoot belongs to a group of fibroproliferative disorders whose origin and multi- hierarchical effect remain unknown. It has been suggested that fibroblasts and growth factors may be involved. To gain a more global view, direct analysis of the protein composition of extra cellular matrix, a proteomic approach was used. At present two principle methods are mostly used for the treatment of clubfoot: physiotherapy and the Ponseti method. The determination of the general biological and biomechanical parameters for various regio ns of the clubfoot can potentially help in the understanding of the mechanisms participating on this serious anomaly and thus contribute to the development of the more efficient therapeutic approach. This review summarizes the present knowledge on the poss ible pathogenetic mechanisms participating in the development of the clubfoot and their possible relation to the new therapeutic approaches., M. Ošťádal, J. Lišková, D. Hadraba, A. Eckhardt., and Obsahuje bibliografii
In the central nervous system (CNS), monocarboxylate transporter 1 (MCT1) is expressed in astrocytes and endothelial cells but also in oligodendroglia. Oligodendroglia support neurons and axons through lactate transportation by MCT1. Limited information is available on the MCT1 expression changes in candidate cells in the developing rat brain, especially in corpus callosum which is the most vulnerable area in demyelinating diseases. In the present study, we investigated the expression pattern of MCT1 during postnatal development in the rat corpus callosum using immunofluorescene staining, Western blotting analysis and RT-PCR. We reported that MCT1 gene and protein were consistently expressed in the rat corpus callosum from birth to adult. MCT1/CNPase and MCT1/GFAP immunofluorescence staining demonstrated that most of MCT1 positive cells were co-labeled with cyclic nucleotide 3′ phosphodiesterase (CNPase) in rat corpus callosum from P7 to adult, whereas MCT1+/GFAP+ cells preserve the dominate position before P7. Moreover, there were significant associations between the expression of MCT1 protein and the expression of myelin basic protein (MBP) (correlation coefficient: r=0.962, P=0.009) from P7 to adult. Similarly, the MCT1 mRNA expression was also significantly associated with MBP mRNA expression (r=0.976, P=0.005). Our results are proposing that in the developing brain white matter, MCT1 is predominately expressed in oligodendrocyte though it mainly expressed in astrocyte in early postnatal, which indicate that MCT1 may involve in the oligodendrocyte development and myelination., F. Dong, Y. Liu, Z. Zhang, R. Guo, L. Ma, X. Qu, H. Yu, H. Fan, R. Yao., and Obsahuje bibliografii
n previous studies, one of the systolic time intervals - preejection period (PEP) - was used as an index of sympathetic activity reflecting the cardiac contractility. However, PEP could be also influenced by several other cardiovascular variables including preload, afterload and diastolic blood pressure (DBP). The aim of this study was to assess the behavior of the PEP together with other potentially confounding cardiovascular system characteristics in healthy humans during mental and orthostatic stress (head-up tilt test - HUT). Forty-nine healthy volunteers (28 females, 21 males, mean age 18.6 years (SD=1.8 years)) participated in the study. We recorded finger arterial blood pressure by volume-clamp method (Finome ter Pro, FMS, Netherlands), PEP, thoracic fluid content (TFC) - a measure of preload, and cardiac output (CO) by impedance cardiography (CardioScreen ®2000, Medis, Germany). Systemic vascular resistance (SVR) - a measure of afterload - was calculated as a ratio of mean arterial pressure and CO. We observed that during HUT, an expected decrease in TFC was accompanied by an increase of PEP, an increase of SVR and no significant change in DBP. During mental stress, we observed a decrease of PEP and an increase of TFC, SVR and DBP. Correlating a change in assessed measures (delta values) between mental stress and previous supinerest, we found that ΔPEP correlated negatively with ΔCO and positively with ΔSVR. In orthostasis, no significant correlation between ΔPEP and ΔDBP, ΔTFC, ΔCO, ΔMBP or ΔSVR was found. We conclude that despite an expected increase of sympathetic activity during both challenges, PEP behaved differently indicating an effect of other confounding factors. To interpret PEP values properly, we recommend simultaneously to measure other variables influencing this cardiovascular measure., J. Krohova, B. Czippelova, Z. Turianikova, Z. Lazarova, I. Tonhajzerova, M. Javorka., and Obsahuje bibliografii
The aim of this study was to assess the effects of radiofrequency electromagnetic field (RF EMF) on heart rate variability (HRV) in rabbits with intensity slightly exceeding the limits for occupations. Totally 21 New Zealand white rabbits divided into two groups were used in this double-blind study. The first group of animals without general anesthesia was subjected to HRV examination under exposure to a device generated RF EMF source (frequency 1788 MHz, intensity 160 V/m, lasting 150 min.). The second group (premedications + α chloralose mg/kg) underwent the same protocol under the exposure to the real RF EMF signal from the base stations of mobile providers (frequency range 1805 - 1870 MHz - corresponding to the downlink signal of Slovak mobile providers, 160 V/m, 150 min., respectively). Individual 5-min records were used to analyze the HRV parameters: heart rate and root Mean Square of the Successive Differences (rMSSD) for time domain analysis and spectral powers in the low (LF-VFS) and high frequency (HF-VFS) bands for frequency domain analysis. Our study revealed the increased in HRV parameters (HF-HRV, rMSSD) associated with lower heart rate indicating increased cardiac vagal control under the exposure to RF EMF in experimental methods., Jakub Misek, Marcel Veterník, Ingrid Tonhajzerova, Viera Jakusova, Ladislav Janousek, Jan Jakus., and Obsahuje bibliografii