Pneumatic tourniquets are widely used in pediatric extremity surgery to provide a bloodless field and facilitate dissection. This prospective study was carried out to examine possible effect of different anesthesia techniques on oxidative stress and endothelial dysfunction connected with ischemia-reperfusion injury during extremity operations at children's age. Patients were randomized into three groups of 15 patients each: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia with propofol (group T) and regional anesthesia (group R). Venous blood samples for determination of the malondialdehyde in plasma and erythrocytes, protein carbonyl groups concentration as well as plasma nitrites and nitrates level and xanthine oxidase activity were obtained at four time points: be fore peripheral nerve block and induction of general anesthesia (baseline), 1 min before tourniquet release, 5 and 20 min after tourniquet release. This study demonstrates that total intravenous anesthesia with propofol and regional anesthesia techniques provide better antioxidant defense and reduce endothelial dysfunct ion than general inhalational anesthesia with sevoflurane during tourniquet application in pediatric extremity surgery., I. Budic ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The present article introduces a novel method of characterizing the macromechanical cartilage properties based on dynamic testing. The proposed approach of instrumented impact testing shows the possibility of more detailed investigation of the acting dynamic forces and corresponding deformations within the wide range of strain rates and loads, including the unloading part of stress-strain curves and hysteresis loops. The presented results of the unconfined compression testing of both the native joint cartilage tissues and potential substitute materials outlined the opportunity to measure the dissipation energy and thus to identify the initial mechanical deterioration symptoms and to introduce a better definition of material damage. Based on the analysis of measured specimen deformation, the intact and pathologically changed cartilage tissue can be distinguished and the differences revealed., F. Varga, M. Držík, M. Handl, J. Chlpík, P. Kos, E. Filová, M. Rampichová, A. Nečas, T. Trč, E. Amler., and Obsahuje bibliografii
Diabetes is a recognized risk factor of heart disease. The abnormalities related to a decreased heart performance probably arise at cellular and molecular levels already in the asymptomatic phase of diabetes. However, the early alterations initiating a sequence of events that culminates in the clinical signs have not been fully elucidated yet. This review deals with some biophysical methods applied to investigation of left ventricular myocytes in rats with streptozotocin diabetes, as well as our most important findings concerning diabetes-induced cell changes which cannot be captured by other techniques. The observed decrease in sarcolemmal membrane fluidity is causatively associated with increased glycation and glycoxidation. On the other hand, an increase in the mitochondrial membrane fluidity may be attributed to augmented energy transduction through the membranes. We reported for the first time concurrent measurements of membrane potential and dynamics, and respiratory chain activities in rat heart mitochondria, as well as calcium transients in the myocytes from diabetic hearts together with the assessed quantitative relationships among these variables. We were able to detect some significant alterations that may underlie myocyte dysfunction and subsequent remodeling of the heart. We suppose that not all these changes reflect mechanisms leading to pathology; some may represent adaptive and compensatory responses to diabetes., I. Waczulíková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
To determine the role of postinspiratory inspiratory activity of the diaphragm in the biphasic ventilatory response to hypoxia in unanesthetized rats, we examined diaphragmatic activity at its peak (DI), at the end of expiration (DE), and ventilation in adult unanesthetized rats during poikilocapnic hypoxia (10 % O2) sustained for 20 min. Hypoxia induced an initial increase in ventilation followed by a consistent decline. Tidal volume (VT), frequency of breathing (fR), DI and DE at first increased, then VT and DE decreased, while fR and DI remained enhanced. Phasic activation of the diaphragm (DI - DE) increased significantly at 10, 15 and 20 min of hypoxia. These results indicate that 1) the ventilatory response of unanesthetized rats to sustained hypoxia has a typical biphasic character and 2) the increased end-expiratory activity of the diaphragm limits its phasic inspiratory activation, but this increase cannot explain the secondary decline in tidal volume and ventilation., H. Maxová, M. Vízek., and Obsahuje bibliografii
Cardiac resynchronization therapy is not commonly used in the early postoperative period in pati ents undergoing cardiac surgery who have left ventricular (LV) dysfunction and a history of heart failure. We performed a prospective randomized clinical trial to compare atrial synchronous right ventricular (DDD RV) and biventricular (DDD BIV) pacing within 72 hours after cardiac surgery in patients with an EF ≤ 35 %, a QRS interval longer than 120 msec and who had LV dyssynchrony detected by real-time three-dimensional echocardiography (RT3DE). Epicardial pacing was provided by a modified Medtronic INSYNC III pacemaker. An LV epicardial pacing lead was implanted on the latest activated segment of the LV based on RT3DE. The study included 18 patients with ischemic heart diseas e, with or without valvular heart disease (14 men, 4 women, average age 71 years). Patients undergoing DDD BIV pacing had a statistically significant greater CO and CI (CO 6.7±1.8 l/min, CI 3.4±0.7 l/min/m²) than patients undergoing DDD RV pacing (CO 5.5±1.4 l/min, CI 2.8±0.7 l/min/m²), p<0.001. DDD BIV paci ng in the early postoperative period after cardiac surgery corrects LV dyssynchrony and has better hemodynamic results than DDD RV pacing., F. Straka ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The production of the pineal hormone melatonin is synchronized with day-night cycle via multisynaptic pathway including suprachiasmatic nucleus linking several physiological functions to diurnal cycle. The recent data indicate that impaired melatonin production is involved in several cardiovascular pathologies including hypertension and ischemic heart disease. However, the mechanisms of melatonin effect on cardiovascular system are still not completely understood. The activation of melatonin receptors on endothelial and vascular smooth muscle cells and antioxidant properties of melatonin could be responsible for the melatonin effects on vascular tone. However, the data from in vitro studies are controversial making the explanation of the melatonin effect on blood pressure in vivo difficult. In vivo, melatonin also attenuates sympathetic tone by direct activation of melatonin receptors, scavenging free radicals or increasing NO availability in the central nervous system. The central and peripheral antiadrenergic action of chronic melatonin treatment might eliminate the mechanisms counter-regulating decreased blood pressure, providing thus additional cardioprotective mechanism. The extraordinary antioxidant activity and antilipidemic effects of melatonin may enhance the modulation of blood pressure by melatonin and probably play the most important role in the amelioration of target organ damage by chronic melatonin treatment. Further investigation of these mechanisms should provide novel knowledge about pathophysiological mechanisms of cardiovascular diseases, additional explanation for their circadian and seasonal variability and potentially generate new impulses for the development of therapeutic arsenal., Ľ. Paulis, F. Šimko., and Obsahuje bibliografii a bibliografické odkazy
The goal of the research is to investigate the special effect of ovarian-menstrual cycle phases on the level of women’s blood pressure and characteristics of Mayer waves. 77 women aged 18-19 were tested under condition close to the state of basal metabolism in follicular phase (I), ovulation (II) and luteal phase (III) of ovarian-menstrual cycle. In phases II and III, the increase of mean and diastolic blood pressure level, in comparison with phase I in the prone position at rest and with psycho-emotional loading, were observed. The distinctions between variation parameters of R-R interval duration, stroke volume and its synchronization in phases II and III, in comparison with phase I, were observed in the prone position at rest, during tilt-test and with psycho-emotional loading. The substantial level of relationship between the power of Mayer waves and mean and diastolic blood pressure, mainly in phase I under conditions of all types, is observed. The maximum peak amplitude of stroke volume spectrogram is associated with pressure levels in the range of 0.04-0.15 Hz (ρ from -0.33 to -0.64). The obtained results indicate the possible participation of spontaneous baroreflex sensitivity characteristics in keeping blood pressure level in women., O. I. Lutsenko, S. O. Kovalenko., and Obsahuje bibliografii
Type 2 diabetes mellitus (T2DM) is associated with increased fracture risk; the underlying mechanism remains unexplained. This study aimed to investigate the relationships between body composition and bone and glucose metabolism in postmenopausal women wit h T2DM. Dual-energy X-ray absorptiometry was used to measure bone mineral density (BMD) and body composition. A total of 68 postme nopausal women with T2DM and 71 controls were eligible for the study. In contrast to normal BMD in T2DM, a similar prevalence of low-trauma fractures was observed in both groups. T2DM women had significantly higher Trunk fat% and A/G ratio and significantly lower Legs LM% and Legs FM%. Legs LM% was significantly lower in fractured T2DM group and negatively correlated with glycaem ia and HbA1c (p<0.01). Serum osteocalcin was significantly lower in T2DM and inversely correlated with FM%, Trunk FM% and A/G ratio (p<0.01) and positively correlated with Legs FM% and total LM% (p<0.05). In conclusion, abdominal obesity and decrease in mu scle mass may contribute to low bone formation in T2DM women. Further research is needed to unravel underlying pathophysiological mechanisms and to determine whether maintenance of muscle mass, especially in the lower extremities and/or reduction of centra l fat mass can prevent fractures., I. Raška Jr., M. Rašková, V. Zikán, J. Škrha., and Obsahuje bibliografii
Variants within the FTO gene are important determinants of body mass index (BMI), but their role in determination of BMI changes after combined dietary/physical ac tivity intervention is unclear. We have analyzed 107 unrelated overweight non-diabetic Czech females (BMI over 27.5 kg/m2 , age 49.2±12.3 years). FTO variants rs17817449 (first intron) and rs17818902 (third intron) were genotyped. The life style mo dification program (10 weeks) consisted of an age- matched reduction of energy intake and exercise program (aerobic exercise 4 times a week, 60 min each). The mean BMI before intervention was 32.8±4.2 kg/m2 and the mean achieved weight loss was 4.8±3.5 kg (5.3±3.5 %, max. -15.5 kg, min. +2.0 kg, p<0. 01). No significant association between BMI decrease and FTO variants was found. Also waist-to-hip ratio, body composition (body fat, water, active tissue), lipid parameters (total, LDL and HDL cholesterol, triglycerides) glucose and hsCRP change s were independent on FTO variants. FTO variants rs17817449 and rs17818902 are not associated with BMI changes after combined short time dietary/physical activity intervention in overweight females., D. Dlouhá ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
In the present paper we describe changes of anatomical parameters in inbred Lewis strain rats, namely their body weight, body weight gain per week, absolute and relative heart, thyroid gland and skeletal muscle weights, that are assumed to reflect experimentally altered thyroid status. The hyperthyroid state was induced by DL-thyroxine or Na 3,3',5-triiodo-L-thyronine, while methimazole was employed for inducing hypothyroidism. We have found that when compared to euthyroid rats, hypothyroidism resulted in a significantly lower body weight gain, absolute and relative heart weight and, in contrast, in a significant increase of absolute and relative thyroid gland weight. On the other hand, hyperthyroidism led to a significant increase of absolute and relative heart weight and to a significant reduction of absolute and relative thyroid gland weight. However, the body mass was not significantly altered in hyperthyroidism as compared with euthyroid rats. We conclude that our protocol leads to chronic hyper- or hypothyroidism as demonstrated by body, heart and thyroid gland weight changes. These anatomical data can thus be utilized as supplemental criteria for the assessment of the thyroid state of experimental rats., T. Soukup, G. Zachařová, V. Smerdu, I. Jirmanová., and Obsahuje bibliografii