National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
Experimental bridging of spinal cord injury with hydrogels
Hejčl, Aleš ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Filip, Stanislav (referee)
Hydrogels are biomaterials used in the treatment of experimental spinal cord injury (SCI). In a model of acute SCI, we implanted hydrogels based on 2-hydroxyethylmethacrylate (HEMA) and hydroxypropylmethacryla-mide (HPMA). One month after implantation the hydrogels bridged the cavity, adhered well to the spinal cord and created permissive environment, infiltrated with blood vessels, axons and Schwann cells. Physical modifications (e.g. surface charge) of hydrogels may improve bridging of acute SCI. We implanted hydrogels based on HEMA with a surface charge in spinal cord hemisection and compared with a hydrogel without charge. Hydrogels with surface charge improved connective tissue adhesion and growth of axons compared to a hydrogel without charge. Biodegradable hydrogels may bridge a lesion followed by complete re-sorption. In a model of acute SCI we implanted hydrogels based on the copolymer of HPMA and etoxyethylmethacrylate (EOMA) degraded from the periphery, which was substituted with new tissue after 1 month, to the center, comprising amorphous residuals of the hydrogel. Delayed hydrogel implantation may improve bridging of spinal cord le-sion. We implanted hydrogels based on HEMA acutely or in a delayed fashion (after 7 days) in spinal cord transection. Delayed implantation re-duced the volume of...
The use of experimental MR imaging in neurosurgery, diagnostic markers in expansive brain processes. Diagnostic markers of patients with normal pressure hydrocephalus
Vlasák, Aleš ; Bradáč, Ondřej (advisor) ; Hejčl, Aleš (referee) ; Krahulík, David (referee)
Despite decades of research of normal pressure hydrocephalus (NPH), a clear pathophysiological mechanism of the disease is sill unknown. This results in the absence of a unambiguous diagnostic biomarker. Moreover, NPH in contrast to similar neurodegenerative diseases is curable by insertion of a ventrikulo-peritoneal shunt. Now the diagnostics is based on invasive functional testing, on the contrary, imaging methods play only a supporting role. This work is processed with an effort to find a sufficiently sensitive and specific biomarker of MRI imaging using advanced analytical methods. For this reason, the structural volumetry and the phase contrast method were tested. The individual partial results of both of these modalities have already been described in the literature, but the conclusions were controversial. The main contribution of this work is the range of tested parameters and their to date untested advanced analysis - accurate automatic segmentation in volumetric study and machine learning algorithms in phase contrast study. In a volumetric study, we segmented a total of 26 structures in 74 patients (29 with diagnosed NPH, 45 without NPH). In the case of preoperative examination, we demonstrated statistically significant differences in the size of the left hippocampus, corpus callosum, left...
Computational Fluid Dynamic Simulation of Intracranial Aneurysms : analysis of time-depend changes of hemodynamic parameters - the road to clinical use
Sejkorová, Alena ; Hejčl, Aleš (advisor) ; Vaverka, Miroslav (referee) ; Přibáň, Vladimír (referee)
Computational Fluid Dynamic Simulation of Intracranial Aneurysms Analysis of time-dependent changes of hemodynamic parameters - the road the clinical use Hemodynamics are involved in the genesis of intracranial aneurysms and time- dependent changes of their parameters lead to aneurysm growth, stabilization or rupture. Definition of these changes using computational fluid hemodynamics could significantly contribute to the understanding of aneurysmal development and rupture and could enable the routine use of mathematical simulations. In this study, computational fluid dynamics were performed for nine incidental aneurysms. Five aneurysms were monitored throughout time and factors leading to aneurysm rupture were analyzed. In four aneurysms the influence of the hemodynamics on the growth was defined. Major growth occurred in areas of low wall shear stress and oscillatory index. These areas increased in size during growth time. Contrary to this, neck shape remodeling occurred in areas with large wall shear stress and pressure. Throughout the follow-up of ruptured aneurysms, the minimal wall shear stress decreased, and the area of low wall shear stress increased significantly. The results indicate that decreasing values of minimal wall shear stress and increasing values of low wall shear stress area...
Experimental Treatment of the Spinal Cord Injury and Clinical Treatment of Thoraco-Lumbar Vertebral Fractures
Krůpa, Petr ; Řehák, Svatopluk (advisor) ; Hejčl, Aleš (referee) ; Hrabálek, Lumír (referee)
Vertebral body fractures together with the spinal cord injury (SCI) remain a challenging medical condition. While management of the thoracic-lumbar (Th-L) vertebral fractures belongs to basic neurosurgical procedures with a usually excellent outcome, treatment of the severe spinal cord injury has mostly unsatisfactory results and thus novel approaches are highly in demand. In this study, experimental treatment of the SCI in a rat model using human mesenchymal stem cells derived from Wharton's jelly (WJ-MSCs) and a novel highly water soluble, nano-formulated curcumin is evaluated. Furthermore, a novel method of mini- invasive percutaneous posterior stabilisation (MIS) of Th-L vertebral fractures is retrospectively compared with classical open posterior (OPEN) procedure. To assess the effectivity of hWJ-MSCs treatment in the ischemic-compression model of SCI in rats, different dosages (0.5 or 1.5 million cells) and repeated applications were compared. Cells or saline were applied intrathecally by lumbar puncture once, or in three consecutive weeks after injury. Nanocurcumin and a vehicle nanocarrier as a control were delivered both locally, immediately after the spinal cord injury, and subcutaneously during the four consecutive weeks after SCI. Rats were assessed for locomotor skills (BBB, flat beam,...
Experimental bridging of spinal cord injury with hydrogels
Hejčl, Aleš ; Syková, Eva (advisor) ; Rokyta, Richard (referee) ; Filip, Stanislav (referee)
Hydrogels are biomaterials used in the treatment of experimental spinal cord injury (SCI). In a model of acute SCI, we implanted hydrogels based on 2-hydroxyethylmethacrylate (HEMA) and hydroxypropylmethacryla-mide (HPMA). One month after implantation the hydrogels bridged the cavity, adhered well to the spinal cord and created permissive environment, infiltrated with blood vessels, axons and Schwann cells. Physical modifications (e.g. surface charge) of hydrogels may improve bridging of acute SCI. We implanted hydrogels based on HEMA with a surface charge in spinal cord hemisection and compared with a hydrogel without charge. Hydrogels with surface charge improved connective tissue adhesion and growth of axons compared to a hydrogel without charge. Biodegradable hydrogels may bridge a lesion followed by complete re-sorption. In a model of acute SCI we implanted hydrogels based on the copolymer of HPMA and etoxyethylmethacrylate (EOMA) degraded from the periphery, which was substituted with new tissue after 1 month, to the center, comprising amorphous residuals of the hydrogel. Delayed hydrogel implantation may improve bridging of spinal cord le-sion. We implanted hydrogels based on HEMA acutely or in a delayed fashion (after 7 days) in spinal cord transection. Delayed implantation re-duced the volume of...

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