Implementation of Integration Testing Test Case Generation Tool

katedra řídicí technik

Contribution to the Hemodynamic of Vascular Anastomosis

The primary objective of the research project was the optimization of geometry of the infrainguinal prosthetic bypass in the site of the distal end-to-side anastomosis. Due to the negative influence of hemodynamics, it is most frequently this location, which is responsible for the longterm failure of the graft. Our prospective angiographic study in patients as well as experimental and computational simulations indicate that flow type in the anastomosis and wall shear stress (WSS) in particular are the key factors that determine the location of neointimal hyperplasia and promote its progression. Maximum of such changes was located in the toe, heel, and bottom of the anastomosis, and these clinical findings correspond with the results from the simulations. We carried out several clinical experiments that suggest the importance of the angle of the distal anastomosis of an infrainguinal prosthetic bypass as a key factor in the development (both location and quantity) of neointimal hyperplasia 6 to 24 months following the procedure. The construction of the anastomosis at a more acute angle results in WSS values that are closer to physiological flow. This reduces both mechanical impairment of the endothelial cells and stimulation of the smooth muscle cells. From the researched set of anastomotic angles (25ř, 45ř,..

Contribution to the Hemodynamic of Vascular Anastomosis

Hlavním cílem práce bylo optimalizovat cévní spojení infrainguinálních protetických rekonstrukcí v oblasti distální end-to-side anastomózy, jakožto místa, kde dochází k nejčastějšímu selhání rekonstrukce v důsledku negativního vlivu hemodynamiky a tím minimalizovat procento selhání bypassu. Klinické i experimentální ověření jasně prokázalo, že hemodynamika - charakter krevního proudu v anastomóze, a především smykové napětí (WSS) hraje klíčovou roli ve vzniku, progresi a lokalizaci stenóz v případě intimomediální hyperplazie. Bylo potvrzeno, že maximum změn se odehrává ve špičce, patě a na dně anastomózy. Při provedení celé řady experimentů se jednoznačně potvrdila hypotéza, stanovená na podkladě klinických vyšetření a numerické simulace, že úhel napojení distální anastomózy infrainguinálních protetických rekonstrukcí, sehrává klíčovou úlohu v selhání těchto rekonstrukcí v časové periodě od půl roku do dvou let po provedeném výkonu na vrub intimomediální hyperplazie. Právě úhel anastomózy, rozhoduje do jaké míry se rozvinou změny ve smyslu intimomediální hyperplazie. Prokázali jsme, že čím menší je úhel, pod kterým byla anastomóza našita, tím více se hodnoty WSS přibližují fyziologickým hodnotám. Tím dochází k minimalizaci poškozování buněk endotelu a také eliminaci následné negativní stimulace buněk hladké...The primary objective of the research project was the optimization of geometry of the infrainguinal prosthetic bypass in the site of the distal end-to-side anastomosis. Due to the negative influence of hemodynamics, it is most frequently this location, which is responsible for the longterm failure of the graft. Our prospective angiographic study in patients as well as experimental and computational simulations indicate that flow type in the anastomosis and wall shear stress (WSS) in particular are the key factors that determine the location of neointimal hyperplasia and promote its progression. Maximum of such changes was located in the toe, heel, and bottom of the anastomosis, and these clinical findings correspond with the results from the simulations. We carried out several clinical experiments that suggest the importance of the angle of the distal anastomosis of an infrainguinal prosthetic bypass as a key factor in the development (both location and quantity) of neointimal hyperplasia 6 to 24 months following the procedure. The construction of the anastomosis at a more acute angle results in WSS values that are closer to physiological flow. This reduces both mechanical impairment of the endothelial cells and stimulation of the smooth muscle cells. From the researched set of anastomotic angles (25ř, 45ř,...2nd Department of Surgery-Clinical Department of Cardiovascular Surgery First Faculty of MedicineII. chirurgická klinika - kardiovaskulární chirurgie 1.LF a VFN v prazeFirst Faculty of Medicine1. lékařská fakult

Juxtarenal Mycotic Aneurysm as a Complication of Acute Exacerbation of Chronic Cholecystitis Treated by Resection and Replacement by a Fresh Allograft

We present a case of a female patient with infectious (mycotic) juxtarenal abdominal aneurysm with atypical symptoms beginning as acute exacerbation of chronic cholecystitis. Apart from common antibiotic treatment, the patient successfully underwent resection of the diseased segment and replacement by a fresh allograft in order to reduce the risk of infection of the graft, but with the need of subsequent life-long immunosuppressive therapy. Perioperative monitoring of the spinal cord by near infrared spectroscopy was used to identify possible spinal ischemia. The choice of the fresh allograft was based on our experience supported by review of the literature

Budd-Chiari Syndrome

Budd-Chiari syndrome (BCS) is a rare disease with an incidence of 0.1 to 10 per million inhabitants a year caused by impaired venous outflow from the liver mostly at the level of hepatic veins and inferior vena cava. Etiological factors include hypercoagulable conditions, myeloprolipherative diseases, anatomical variability of the inferior vena cava, and environmental conditions. Survival rates in treated patients range from 42 to 100% depending on the etiology and the presence of risk factors including parameters of Child-Pugh score, sodium and creatinine plasma levels, and the choice of treatment. Without treatment, 90% of patients die within 3 years, mostly due to complications of liver cirrhosis. BCS can be classified according to etiology (primary, secondary), clinical course (acute, chronic, acute or chronic lesion), and morphology (truncal, radicular, and venooclusive type). The diagnosis is established by demonstrating obstruction of the venous outflow and structural changes of the liver, portal venous system, or a secondary pathology by ultrasound, computed tomography, or magnetic resonance. Laboratory and hematological tests are an integral part of the comprehensive workup and are invaluable in recognizing hematological and coagulation disorders that may be identified in up to 75% of patients with BCS. The recommended therapeutic approach to BCS is based on a stepwise algorithm beginning with medical treatment (a consensus of expert opinion recommends anticoagulation in all patients), endovascular treatment to restore vessel patency (angioplasty, stenting, and local thrombolysis), placement of transjugular portosystemic shunt (TIPS), and orthotopic liver transplantation as a last resort rescue treatment

In Vivo Contrast Imaging of Rat Heart with Carbon Dioxide Foam

Widely used classical angiography with the use of iodine contrast agents is highly problematic, particularly in patients with diabetes mellitus, cardiac and pulmonary diseases, or degree III or IV renal insufficiency. Some patients may be susceptible to allergic reaction to the iodine contrast substance. The intravenous injection of a bolus of CO2 (negative contrast) is an alternative method, which is, however, currently only used for imaging blood vessels of the lower limbs. The aim of our project was to design and test on an animal model a methodology for injecting the CO2 foam which would minimize the possibility of embolization of the brain tissue and heart infarction, leading to their damage. This is important research for the further promotion of the use of CO2, which is increasingly important for endovascular diagnosis and treatment, because carbon-dioxide-related complications are extremely rare. CO2 foam was prepared by the rapid mixing in a 2:1 ratio of CO2 and fetal bovine serum (FBS)-enriched Dulbecco’s Modified Eagle Medium (DMEM). Freshly prepared CO2 foam was administered into the catheterized rat tail vein or cannulated rat abdominal aorta and inferior vena cava (IVC). CO2 foam was compared with commercially available microbubbles (lipid shell/gas core). The rat heart in its parasternal long axis was imaged in B-Mode and Non-linear Contrast Mode before/during and after the contrast administration. Samples of the brain, heart and lungs were collected and subjected to histological examination. The non-linear contrast imaging method enables the imaging of micron-sized gas microbubbles inside a rat heart. The significantly shorter lifetime of the prepared CO2 foam is a benefit for avoiding the local ischemia of tissues

Rifampin-Releasing Triple-Layer Cross-Linked Fresh Water Fish Collagen Sponges as Wound Dressings

Objectives. Surgical wounds resulting from biofilm-producing microorganisms represent a major healthcare problem that requires new and innovative treatment methods. Rifampin is one of a small number of antibiotics that is able to penetrate such biofilms, and its local administration has the potential to serve as an ideal surgical site infection protection and/or treatment agent. This paper presents two types (homogeneous and sandwich structured) of rifampin-releasing carbodiimide-cross-linked fresh water fish collagen wound dressings. Methods. The dressings were prepared by means of the double-lyophilization method and sterilized via gamma irradiation so as to allow for testing in a form that is able to serve for direct clinical use. The mechanical properties were studied via the uniaxial tensile testing method. The in vivo rifampin-release properties were tested by means of a series of incubations in phosphate-buffered saline. The microbiological activity was tested against methicillin-resistant staphylococcus aureus (MRSA) employing disc diffusion tests, and the in vivo pharmacokinetics was tested using a rat model. A histological examination was conducted for the study of the biocompatibility of the dressings. Results. The sandwich-structured dressing demonstrated better mechanical properties due to its exhibiting ability to bear a higher load than the homogeneous sponges, a property that was further improved via the addition of rifampin. The sponges retarded the release of rifampin in vitro, which translated into at least 22 hours of rifampin release in the rat model. This was significantly longer than was achieved via the administration of a subcutaneous rifampin solution. Microbiological activity was proven by the results of the disc diffusion tests. Both sponges exhibited excellent biocompatibility as the cells penetrated into the scaffold, and virtually no signs of local irritation were observed. Conclusions. We present a novel rifampin-releasing sandwich-structured fresh water fish collagen wound dressing that has the potential to serve as an ideal surgical site infection protection and/or treatment agent