High frequency oscillatory ventilation (HFOV), contrary to conventional ventilation, enables a safe increase in tidal volume (VT) without endangering alveoli by volutrauma or barotrauma. The aim of the study is to introduce the concept of normocapnic high frequency oscillatory hyperventilation and to assess its effect upon oxygen gain under experiment al conditions. Laboratory pigs (n=9) were investigated under total intravenous anesthesia in three phases. Phase 1: Initial volume controlled HFOV period. Phase 2 : Hyperventilation - VT was increased by (46 ± 12) % when compared to normocapnic VT during phase 1. All other ventilatory parameters were unchanged. A significant increase in PaO 2 (by 3.75 ± 0.52 kPa, p<0.001) and decrease in PaCO 2 (by -2.05 ± 0.31 kPa, p<0.001) were obtained. Phase 3: Normocapnia during hyperventilation was achiev ed by an iterative increase in the CO 2 fraction in the inspiratory gas by a CO2 admixture. All ventilatory parameters were unchanged. A significant increase in PaO2 (by 3.79 ± 0.73 kPa, p<0.001), similar to that which was observed in phase 2, was preserved in phase 3 whereas normocapnia was fully re-established. The concept of high frequency normocapnic hyperventilation offers a lung protective strategy that significantly improves oxygenation whilst preserving normocapnia., K. Roubík, J. Pachl, V. Zábrodský., and Obsahuje bibliografii a bibliografické odkazy
Cardiac fibroblast-myofibroblast transformation (CMT) is a critical event in the initiation of myocardial fibrosis. Notch signaling has been shown to regulate myofibroblast transformation from other kinds of cells. However, whether Notch signaling is also involved in CMT remains unclear. In the present study, expressions of Notch receptors in cardiac fibroblasts (CFs) were examined, effects of Notch signaling inhibi tor N-[N-(3,5-difluorophenacetyl)- l-alanyl]-S-phenylglycine t-butyl ester (DAPT) and transforming growth factor-β1 (TGF-β1) on CMT were determined by increasing alpha-smooth muscle actin (α-SMA) expression and collagen synthesis, and Notch signaling was examined by analyzing expressions of Notch receptors. The results showed that: (1) Notch receptor 1, 2, 3 and 4 were all expressed in CFs; (2) DAPT promoted CMT in a time -dependent manner; (3) During the period of CMT induced by TGF-β1, expressions of Notch receptor 1, 3 and 4 in CFs were down-regulated, whereas there was no change for Notch receptor 2. Moreover, the downtrends of Notch 1, 3 and 4 were corresponding to the trend growth of α-SMA expression and collagen synthesis. These results suggested that inhibiting of Notch signaling might promote CMT. The down-regulations of Notch receptor 1, 3 and 4 induced by TGF-β1 may facilitate CMT. In conclusion, inhibition of Notch signaling might be a novel mech anism of CMT in myocardial fibrosis., Y.-H. Fan ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Fibroblast growth factor-21 (FGF-21) has been recently characterized as a new adipokine. The aim of this study was to assess FGF-21 levels in patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and to study the relationship between FGF-21, disease activity and metabolic status. The levels of FGF- 21 in serum and synovial fluid samples from 38 patients with RA and 42 control individuals with OA were determined by ELISA. Patients were assessed for disease activity using the disease activity score (DAS28), a serum glucose and lipid profile. Age, sex and BMI-adjusted FGF-21 levels in the serum (p=0.024) and synovial fluid (p=0.010) samples were significantly higher in patients with RA when compared with OA. The levels of FGF-21 in the serum significantly correlated with the levels in the synovial fluid. Serum and synovial fluid FGF-21 levels adjusted for confounders correlated positively with C-reactive protein. The levels of FGF-21 were positively correlated with BMI in patients with RA; however, the levels were not associated with disease activity or lipid profiles. Furthermore, serum FGF-21 levels were significantly higher in seropositive compared with seronegative RA patients. This work shows that patients with seropositive RA have increased levels of FGF-21. The results suggest that FGF-21 is related to BMI but not disease activity or lipid profiles in patients with RA., H. Hulejová ... [et al.]., and Obsahuje seznam literatury
Excessive production of reactive oxygen species (ROS) are implicated in the pathogenesis of numerous disease states. However, direct measurement of in vivo ROS in humans has remained elusive due to limited access to appropriate tissue beds and the inherently short half-lives and high reactivity of ROS. Herein, we describe a novel technique by which to measure in vivo ROS in human skeletal muscle. Microdialysis probes were inserted into the vastus lateralis of eight healthy volunteers. Amplex Ultrared, a highly specific fluorogenic substrate for hydrogen peroxide (H2O2), and horseradish peroxidase (HRP), were perfused through microdialysis probes, and outflowing dialysate was collected and fluorescence was measured. Extracellular H2O2 that crossed the microdialysis membrane was measured via fluorescence of the dialysate. Superoxide dismutase (SOD) was then added to the inflowing perfusion media to convert any superoxide crossing the microdialysis membrane to H2O2 within the microdialysis probe. Fluorescence significantly increased (P=0.005) upon SOD addition. These data demonstrate the feasibility of measuring both in vivo H2O2 and superoxide in the extracellular environment of human skeletal muscle, providing a technique with a potential application to a wide range of circulatory and metabolic studies of oxidative stress., J. D. La Favor, E. J. Anderson, R. C. Hickner., and Obsahuje bibliografii
The oxidative stress plays an important role in the development of cardiovascular diseases (CVD). In CVD progression an aberrant redox regulation was observed. In this regulation levels of reactive oxygen species (ROS) play an important role in cellular signaling, where Nrf2 is the key regulator of redox homeostasis. Keap1-Nrf2-ARE system regulates a great set of detoxificant and antioxidant enzymes in cells after ROS and electrophiles exposure. In this review we focus on radical-generating systems in cardiovascular system as well as on Nrf2 as a target against oxidative stress and a key player of redox regulation in cardiovascular diseases. We also summarize the current knowledge about the role of Nrf2 in pathophysiology of several CVD (hypertension, cardiac hypertrophy, cardiomyopathies) as well as in cardioprotection against myocardial ischemia/ reperfusion injury., M. Barančík, L. Grešová, M. Barteková, I. Dovinová., and Obsahuje bibliografii
Disorders of ATP synthase, the key enzyme of mitochondrial energy provision belong to the most severe metabolic diseases presenting as early- onset mitochondrial encephalo- cardiomyopathies. Up to now, mutations in four nuclear genes were associated with isolated deficiency of ATP synthase. Two of them, ATP5A1 and ATP5E encode enzyme’s st ructural subunits α and ε , respectively, while the other two ATPAF2 and TMEM70 encode specific ancillary factors that facilitate the biogenesis of ATP synthase. All these defects share a similar biochemical phenotype with pronounced decrease in the content of fully assembled and functional ATP synthase complex. However, substantial differences can be found in their frequency, molecular mechanism of pathogenesis, clinical manifestation as well as the course of the disease progression. While for TMEM70 the number of reported patients as well as spectrum of the mutations is steadily increasing, mutations in ATP5A1, ATP5E and ATPAF2 genes are very rare. Apparently, TMEM70 gene is highly prone to mutagenesis and this type of a rare mitochondrial disease has a rather frequent incidence. Here we present overview of individual reported cases of nuclear mutations in ATP synthase and discuss, how their analysis can improve our understanding of the enzyme biogenesis., K. Hejzlarová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Associations between different infectious agents and obesity have been reported in humans for over thirty years. In many cases, as in nosocomial infections, this relationship reflects the greater susceptibility of obese individuals to infection due to impaired immunity. In such cases, the infection is not related to obesity as a causal factor but represents a complication of obesity. In contrast, several infections have been suggested as potential causal factors in human obesity. However, evidence of a causal linkage to human obesity has only been provided for adenovirus 36 (Adv36). This virus activates lipogenic and proinflammatory pathways in adipose tissue, improves insulin sensitivity, lipid profile and hepatic steatosis. The E4orf1 gene of Adv36 exerts insulin senzitizing effects, but is devoid of its pro-inflammatory modalities. The development of a vaccine to prevent Adv36- induced obesity or the use of E4orf1 as a ligand for novel antidiabetic drugs could open new horizons in the prophylaxis and treatment of obesity and diabetes. More experimental and clinical studies are needed to elucidate the mutual relations between infection and obesity, identify additional infectious agents causing human obesity, as well as define the conditions that predispose obese individuals to specific infections., V. Hainer, H. Zamrazilová, M. Kunešová, B. Bendlová, I. Aldhoon-Hainerová., and Obsahuje bibliografii