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Feeding artery of vascular accesses for hemodialysis: model of arterial adaptation to high blood flow
Tuka, Vladimír ; Malík, Jan (advisor) ; Vízek, Martin (referee) ; Zicha, Josef (referee)
Background: Arteries adapt their diameter to changing haemodynamic conditions to maintain constant wall shear stress, the force generated by flowing blood on endothelial cells. The feeding artery of haemodialysis vascular accesses is a human model of arterial adaptation to chronically high blood flow and thus to high wall shear stress. The process of arterial adaptation is endothelium dependent. Endothelial dysfunction related to End-Stage Renal Failure, diabetes mellitus, dyslipidemia may impair also the dilatation of the feeding artery of vascular accesses. First the review of the literature presents in three parts different aspects of arterial adaptation: 1) arterial adaptation with focusing on the role of haemodynamic factors, 2) the influence of end-stage renal disease on arterial adaptation, 3) feeding artery of vascular accesses as a model of arterial response to chronic increase in blood flow. Methods: We examined the feeding artery of radial and brachial polytetrafluoroethylene grafts shortly after and one and two years after access creation. We used duplex ultrasonography to obtain internal diameter and blood velocity in the feeding arteries. We calculated wall shear rate as 4 x blood velocity / internal diameter and used it as approximation of wall shear stress. Results: In the first study we...
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Assessment of the Cathetrization Programme in a Haemodialysis Centre
Mašek, Petr ; Malík, Jan (referee) ; Lopot, František (advisor)
This diploma thesis deals with complex quality assessment of catheterization programme run at Strahov Internal Medicine Department of the General Faculty Hospital in Prague. The evaluation was done according to K/DOQI 2006 international guidelines. The aim was to evaluate primary success of catheterization, probability of maintaining catheter functionality in time, the risk of its thrombotization and presence of infection. The evaluation was performed using Kaplan-Meier method. Moreover, the effect of additional enhancements for maintaining catheter functionality (TEGO Connector, Biopatch, heparin and Citra-LockTM) and the predictive value of selected hematologic parameters of long-term functionality of the catheters (hematocrit, plasma D-dimers) was assessed. The latter was performed on a small sample of patients. The possibility of detection of the catheter point position by measuring recirculation and its effect on dialysis was investigated by comparing X-ray control of the catheter point position to the value of recirculation measured on catheters connected either normally or inversely to the extracorporeal circulation device. Significance of the pressure values measured at input and output catheter lines was evaluated as a possible marker of the catheter functionality. Based on the analysis results,...
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Wall shear stress and its role in progress of atherosclerosis
Chytilová, Eva ; Malík, Jan (advisor) ; Horký, Karel (referee) ; Piťha, Jan (referee)
Atherosclerosis is associated with systemic risk factors such as hypertension, hyperlipidemia, diabetes mellitus and smoking. Nonetheless, atherosclerosis is a focal disease, preferentially affecting predisposed areas. The main local hemodynamic factor is wall shear stress, the frictional force acting tangencially on the endothelial cell surface. The effect of wall shear stress depends on its magnitude and direction, as well as on the characteristic of vessel geometry and blood flow. Wall shear stress is an important determinant of endothelial function and phenotype. Previous research showed that arterial sites with chronically low WSS are more prone to the development of atherosclerotic plaques. Mostly, it is the case of outer wall of arterial bifurcations, where the stroma of vessel wall prevents arterio-constriction in response to low WSS. However, lower WSS was described also in straight arterial segments, such as carotid arteries, in the presence of atherosclerosis risk factors.
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Jehlička, Petr ; Piťha, Jan (advisor) ; Urbanová, Zuzana (referee) ; Malík, Jan (referee)
MUDr. JEHLIČKA SUMMARY This study has focused on a new method for the assessment of endothelial dysfunction (ED) using the Deceleration Index (DI). A total of 242 ultrasonographic examinations were performed in 92 children (FH 32, DM1 30, healthy controls 3O). The average DI values were 21.8%(±9.4)in healthy children, 19.9%(±9)in FH and 17.6%(±14)in the DM1 group. There were statistically insignificant differences between the study groups. This was most probably due to the high biological variability of the method employed. The coefficient of variation of DI was 1.02 (0.68 -1.53). Therefore, the clinical usefulness of DI is limited with regards to the individual assessment of ED and thus for the prediction of cardiovascular risk. The association of ADMA and oxLDL with ED and their superior sensitivity compared to DI and FMD has been confirmed in our study. Folic acid supplementation did not lead to a statistically signifiant improvement of DI and FMD. Similarly, plasma levels of ADMA and oxLDL remained unchanged despite a decrease of homocysteine and hsCRP in these children. This finding demonstrates a complicated relationship between ADMA, homocysteine and folic acid. The protective effect of folic acid on ED in high risk children was not confirmed in this study.
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Stavební řízení v praxi
Malík, Jan
This bachelor thesis deals with the analysis and description of current legislation of the building control and the planning permission procedure. The theoretical part contains an analysis of the building control and planning permission procedure, including the current building code and changes in building law. The practical part focuses on specific example of building a house. The discussion is a summary of the positives and negatives of changes in current building law.
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