269 results on '"Guler I"'
Search Results
252. Short-term effects of Ankaferd hemostat for renal artery embolization: an experimental study.
- Author
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Ozbek O, Acar K, Koc O, Saritas K, Toy H, Solak Y, Ozbek S, Kucukapan A, Guler I, Gaipov A, Turk S, and Haznedaroglu IC
- Subjects
- Angiography, Animals, Contrast Media pharmacology, Female, Fluoroscopy, Sheep, Domestic, Embolization, Therapeutic methods, Plant Extracts pharmacology, Renal Artery
- Abstract
Purpose: Renal artery embolization (RAE) is a minimally invasive therapeutic technique that is utilized in a number of disorders. Ankaferd is a novel hemostatic agent with a new mechanism of action independent of clotting factors. We used Ankaferd for RAE in a sheep model., Methods: Seven adult female sheep were included in the study. Selective renal arteriogram using 5-F diagnostic catheter was performed to make sure that each kidney was fed by a single renal artery and the animal had normal renal vasculature. Coaxial 2.7-F microcatheter was advanced to the distal main renal artery. Under fluoroscopic guidance, 2 mL of Ankaferd mixed with 2 mL of nonionic iodinated contrast agent was slowly injected. Fluoroscopy was used to observe the deceleration of flow and stagnation. Control renal angiograms were performed just after embolization. After the procedure, the animals were observed for 1 day and then sacrificed with intravenous sodium thiopental., Results: The technical success was observed in seven of the seven animals.. After embolization procedure, none of the animals died or experienced a major systemic adverse event. On macroscopic examination of the embolized kidneys, thrombus at the level of main renal artery formed after Ankaferd embolization was more compact compared with the thrombi that was not Ankaferd-associated, which was observed elsewhere. Microscopically, majority of the renal tubular cells (80-90 %) were necrotic, and there was epithelial cell damage in a small portion of the cells (10-20 %)., Conclusions: RAE was safe and effective in the short-term with Ankaferd in studied animals. Further studies should be conducted to better delineate the embolizing potential of this novel hemostatic agent.
- Published
- 2013
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253. An exceedingly rare type of renal cyst: amoebic cyst.
- Author
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Ozbek O, Odev K, Solak Y, Fevzioglu B, and Guler I
- Subjects
- Aged, Humans, Male, Rare Diseases diagnosis, Tomography, X-Ray Computed, Amebiasis diagnosis, Kidney Diseases, Cystic diagnosis
- Published
- 2013
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254. Association of pulmonary artery obstruction index with elevated heart-type fatty acid binding protein and short-term mortality in patients with pulmonary embolism at intermediate risk.
- Author
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Gul EE, Can I, Guler I, Yesildag A, Abdulhalikov T, Kayrak M, Ozdemir K, and Gok H
- Subjects
- Arterial Occlusive Diseases blood, Biomarkers blood, Female, Follow-Up Studies, Heart physiopathology, Humans, Male, Middle Aged, Predictive Value of Tests, Pulmonary Artery diagnostic imaging, Risk, Survival Analysis, Tomography, X-Ray Computed methods, Ventricular Dysfunction, Right blood, Ventricular Dysfunction, Right diagnostic imaging, Ventricular Dysfunction, Right mortality, Arterial Occlusive Diseases diagnostic imaging, Arterial Occlusive Diseases mortality, Fatty Acid-Binding Proteins blood, Pulmonary Embolism blood, Pulmonary Embolism mortality
- Abstract
Purpose: Heart-type fatty acid binding protein (H-FABP) is a sensitive marker of myocardial injury and predictor of worse prognosis in patients with pulmonary embolism (PE). Assessment of right ventricular dysfunction and pulmonary artery obstruction index (PAOI) with computed tomography (CT) has been reported as a predictor of mortality in PE. Therefore, we aimed to assess the correlation between H-FABP and CT angiographic PAOI in PE patients at intermediate risk., Materials and Methods: Sixty-one patients (28 males; mean age, 62 ± 17 years) with diagnosis of PE were included in this study. CT was performed in all patients, and the following parameters were evaluated: right ventricle/left ventricle ratio (RV/LV), pulmonary artery axial diameter, superior vena cava axial diameter, and PAOI determined with Qanadli score. Blood samples were assessed for H-FABP and troponin levels. Patients were followed for 30 days after discharge., Results: Mean PAOI was 57 ± 18%. Eleven patients died during the follow-up period due to PE (18% mortality rate). H-FABP was positive in 21 patients (35%). There was no difference in CT parameters between patients with positive H-FABP and negative H-FABP. In addition, CT parameters were similar between patients who survived and those who did not. RV/LV ratio correlated with PAOI score. Among the biomarkers, troponin levels correlated with both RV/LV ratio and PAOI. H-FABP was an independent predictor of mortality. PAOI and RV/LV ratio did not predict 30-day mortality., Conclusion: Although H-FABP positivity confers a bad prognosis on PE patients at intermediate risk, PAOI did not predict mortality in this group.
- Published
- 2012
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255. Predictors of kidney dimensions measured by multi-detector computed tomography (MDCT) in 930 middle-aged and elderly patients.
- Author
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Ozbek O, Solak Y, Guler I, Ozbiner H, Ozbek S, Turkmen K, Nayman A, Biyik Z, Samur C, and Turk S
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- Aged, Aged, 80 and over, Female, Glomerular Filtration Rate, Humans, Kidney physiology, Male, Middle Aged, Organ Size, Prospective Studies, Kidney anatomy & histology, Kidney diagnostic imaging, Multidetector Computed Tomography
- Abstract
Purpose: A few studies investigated renal size using computed tomography (CT) in middle-aged and elderly patients while taking renal function into account. Thus, we aimed to assess kidney dimensions and their predictors in patients without known renal disease by multi-detector computed tomography (MDCT)., Methods: This is a 6-month-long prospective observational study. Estimated glomerular filtration rate (eGFR) was calculated with Cockcroft-Gault (CG) and modification of diet in renal disease (MDRD) formulas. Pole-to-pole kidney length (R1) was determined from coronal and sagittal oblique images. Kidney length (R2), width (R3), and parenchymal thickness were measured in axial slices., Results: The data of the 930 patients were included in this study. CG-eGFR was more closely correlated with R1, R2, and R3 than MDRD-eGFR. CG-eGFR, female gender, and presence of diabetes mellitus were independent predictors of R1 size in logistic regression analyses., Conclusion: Kidney sizes diminish with advancing age. CG-eGFR shows a better correlation with kidney dimensions compared with MDRD. Overall, age was a stronger determinant of eGFR than renal dimensions.
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- 2012
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256. A dissolution-diffusion model for the TAXUS drug-eluting stent with surface burst estimated from continuum percolation.
- Author
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Barocas V, Drasler W 2nd, Girton T, Guler I, Knapp D, Moeller J, and Parsonage E
- Subjects
- Diffusion, Microscopy, Atomic Force, Models, Theoretical, Paclitaxel administration & dosage, Solubility, Surface Properties, Drug Delivery Systems, Stents
- Abstract
A two-layer dissolution-diffusion model is derived which incorporates a surface burst component that is estimated from continuum percolation models of overlapping Poisson distributed spheres. The model is shown to adequately describe the release properties of paclitaxel from a hydrophobic polymer matrix, including the surface burst and sustained release dependence on drug loading., ((c) 2008 Wiley Periodicals, Inc.)
- Published
- 2009
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257. Impact of luteal phase support on pregnancy rates in intrauterine insemination cycles: a prospective randomized study.
- Author
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Erdem A, Erdem M, Atmaca S, and Guler I
- Subjects
- Adult, Female, Follicle Stimulating Hormone blood, Gels, Humans, Infertility, Female blood, Insemination, Artificial, Homologous, Luteal Phase drug effects, Male, Ovulation Induction methods, Pregnancy, Progesterone therapeutic use, Prospective Studies, Recombinant Proteins therapeutic use, Sperm Count, Sperm Motility, Vagina, Follicle Stimulating Hormone therapeutic use, Infertility, Female drug therapy, Insemination, Artificial methods, Luteal Phase physiology, Pregnancy Outcome epidemiology
- Abstract
Objective: To determine the impact of luteal phase support on pregnancy rates in ovarian stimulation and intrauterine insemination (IUI) cycles with gonadotropins in couples with unexplained infertility., Design: Prospective randomized controlled trial., Setting: University-based infertility clinic., Patient(s): Two hundred fourteen couples with unexplained infertility who were treated during 427 ovarian stimulation and IUI cycles with recombinant FSH., Intervention(s): Patients underwent ovarian stimulation with recombinant FSH combined with IUI. Patients randomized into the study group (n = 109) received luteal phase support in the form of vaginal progesterone gel (Crinone 8% gel). Patients randomized into the control group (n = 105) received no luteal phase support., Main Outcome Measure(s): Clinical pregnancy and live birth rate per cycle and per patient., Result(s): Demographic data were found to be homogeneous between the study and control groups. Clinical pregnancy rates per cycle and per patient were significantly higher in the study group (21.1% and 39.4%, respectively) compared with the control group (12.7% and 23.8%, respectively). Live birth rate per cycle and per patient was also significantly higher in patients with luteal support (17.4% and 35.8%, respectively) compared with control subjects (9.3% and 18.1%, respectively)., Conclusion(s): Luteal phase support with vaginal progesterone gel significantly affects the success of ovarian stimulation and IUI cycles in patients with unexplained infertility.
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- 2009
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258. Manometric evaluation of anal sphincter function after vaginal and cesarean delivery.
- Author
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Yilmaz E, Nas T, Korucuoglu U, and Guler I
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- Adult, Episiotomy, Female, Gravidity, Humans, Manometry, Perineum anatomy & histology, Pregnancy, Young Adult, Anal Canal physiology, Cesarean Section, Parturition
- Abstract
Objective: To compare anal sphincter function following spontaneous vaginal delivery and cesarean delivery, and assess the association of perineal length and sphincter injury with each delivery mode., Method: Perineal length was measured and anal manometric measurements were performed in 120 primigravidas before and after delivery., Results: Mean values for maximum anal resting and squeeze pressures were significantly lower after delivery irrespective of the mode of delivery, but there was a positive correlation between postpartum maximum anal resting pressure and perineal length (r=0.24, P<0.01)., Conclusion: Anal sphincter function was disturbed after both vaginal and cesarean delivery, a finding weakened by the fact that almost half of the cesareans were performed for cephalopelvic disproportion identified during labor.
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- 2008
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259. Effect of extracellular matrix elements on the transport of paclitaxel through an arterial wall tissue mimic.
- Author
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Sirianni RW, Kremer J, Guler I, Chen YL, Keeley FW, and Saltzman WM
- Subjects
- Antineoplastic Agents, Phytogenic chemistry, Aorta metabolism, Arteries pathology, Diffusion, Dose-Response Relationship, Drug, Elastin chemistry, Endothelium, Vascular pathology, Exons, Extracellular Matrix metabolism, Glass, Humans, Microscopy, Fluorescence, Models, Statistical, Paclitaxel chemistry, Reproducibility of Results, Antineoplastic Agents, Phytogenic pharmacokinetics, Arteries drug effects, Paclitaxel pharmacokinetics
- Abstract
Paclitaxel (PTx) is reported to have an nonuniform steady-state concentration profile in the arterial wall. We utilized epifluorescence microscopy to make precise measurements of fluorescently-labeled PTx (F-PTx) distribution through an in vitro tissue mimic which contained varying concentrations of fibrin, elastin, soybean oil, palmitic acid, and solid glass beads. As little as 0.5 mg/mL of elastin in agarose produced a 50% drop in the measured diffusion coefficient, while as much as 10 mg/mL of fibrin in agarose was required for the same reduction in rate of transport. Because no reduction in the measured diffusion coefficient was observed for solubilized, extracted elastin or unassembled elastin-like polypeptides, the effect was specific to elastic fibers that closely resembled the native elastin network. Collectively, this work identifies a potential source for the high degree of partitioning observed for PTx in native tissue and further develops an in vitro technique for exploring complex tissue-drug interactions.
- Published
- 2008
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260. Role of antral follicle count in controlled ovarian hyperstimulation and intrauterine insemination cycles in patients with unexplained subfertility.
- Author
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Erdem M, Erdem A, Guler I, and Atmaca S
- Subjects
- Adult, Birth Rate, Female, Humans, Infertility, Female pathology, Insemination, Artificial, Pregnancy, Pregnancy Rate, Prospective Studies, Ultrasonography, Infertility, Female physiopathology, Ovarian Follicle cytology, Ovary diagnostic imaging, Ovulation Induction
- Abstract
Objective: To determine the predictive value of basal antral follicle count (AFC) as a marker for pregnancy, live birth rate, and ovarian response in COH and intrauterine insemination (IUI) cycles in couples with unexplained subfertility., Design: Prospective analysis., Setting: University-based infertility clinic., Patient(s): One hundred forty-five women who were treated during 283 COH and IUI cycles with recombinant FSH., Intervention(s): Basal AFC by transvaginal ultrasonography and basal hormone levels were determined on the 3rd day of the treatment cycles., Main Outcome Measure(s): Clinical pregnancy and live birth rate with regard to AFC., Result(s): Antral follicle count significantly correlated negatively with age and total dosage of gonadotropin and correlated positively with number of developing follicles on the day of hCG. Patients with pregnant cycles and live births had significantly more AFC, as compared with nonpregnant cycles. Multiple regression analysis revealed that AFC was the only factor to predict both clinical pregnancy and live birth. The area under the curve for AFC to discriminate clinical pregnancy and live birth, respectively, was 0.77 (95% confidence interval, 0.62-0.79) and 0.718 (95% confidence interval, 0.63-0.82). The cutoff value for AFC for predicting clinical pregnancy and live birth was 7.5 in both cases., Conclusion(s): Lower AFC on basal transvaginal ultrasonography is associated with lower clinical pregnancy and live birth rates in unexplained subfertile couples who are treated with COH and IUI. These data are comparable with those for IVF-intracytoplasmic sperm injection cycles.
- Published
- 2008
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261. Gastroschisis with fetal chromosomal abnormality: a case report.
- Author
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Guler I, Erdem A, Biri A, Gunaydin G, Yilmaz E, Erdem M, and Karaoguz MY
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- Abortion, Induced, Adult, Chorionic Villi Sampling, Female, Fetal Diseases genetics, Gastroschisis diagnosis, Gastroschisis embryology, Gastroschisis genetics, Genetic Counseling, Head and Neck Neoplasms diagnosis, Head and Neck Neoplasms embryology, Head and Neck Neoplasms genetics, Humans, Lymphangioma, Cystic diagnosis, Lymphangioma, Cystic embryology, Lymphangioma, Cystic genetics, Pregnancy, Turner Syndrome diagnosis, Turner Syndrome embryology, Turner Syndrome genetics, Ultrasonography, Prenatal, Chromosome Aberrations embryology, Fetal Diseases diagnosis, Gastroschisis complications, Head and Neck Neoplasms complications, Lymphangioma, Cystic complications, Prenatal Diagnosis methods, Turner Syndrome complications
- Abstract
Gastroschisis is a rare anomaly and it is usually not associated with other syndromic or nonsyndromic anomalies. The first case of gastroschisis with aneuploidy (Turner syndrome) is presented. A fetal huge cystic hygroma was diagnosed by prenatal sonography at 12 weeks of pregnancy and chorionic villi sampling (CVS) was performed. Cytogenetic analysis revealed 45, X0. The pregnancy was terminated by induction of labor at 16 weeks of pregnancy. The female fetus had a big membrane of cystic hygroma surrounding the fetal neck. Additionally, a full abdominal thickness defect with multiple loops of bowel outside the abdomen, which could not be diagnosed on prenatal ultrasound scan, was detected on postnatal examination., (Copyright (c) 2007 S. Karger AG, Basel.)
- Published
- 2007
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262. Circumferential vascular deformation after stent implantation alters wall shear stress evaluated with time-dependent 3D computational fluid dynamics models.
- Author
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LaDisa JF Jr, Olson LE, Guler I, Hettrick DA, Kersten JR, Warltier DC, and Pagel PS
- Subjects
- Animals, Arteries surgery, Blood Flow Velocity, Blood Pressure, Computer Simulation, Elasticity, Equipment Failure Analysis methods, Graft Occlusion, Vascular etiology, Humans, Hyperplasia etiology, Hyperplasia pathology, Hyperplasia physiopathology, Prosthesis Failure, Severity of Illness Index, Shear Strength, Stress, Mechanical, Time Factors, Arteries pathology, Arteries physiopathology, Blood Vessel Prosthesis adverse effects, Graft Occlusion, Vascular pathology, Graft Occlusion, Vascular physiopathology, Models, Cardiovascular, Stents adverse effects
- Abstract
The success of vascular stents in the restoration of blood flow is limited by restenosis. Recent data generated from computational fluid dynamics (CFD) models suggest that stent geometry may cause local alterations in wall shear stress (WSS) that have been associated with neointimal hyperplasia and subsequent restenosis. However, previous CFD studies have ignored histological evidence of vascular straightening between circumferential stent struts. We tested the hypothesis that consideration of stent-induced vascular deformation may more accurately predict alterations in indexes of WSS that may subsequently account for histological findings after stenting. We further tested the hypothesis that the severity of these alterations in WSS varies with the degree of vascular deformation after implantation. Steady-state and time-dependent simulations of three-dimensional CFD arteries based on canine coronary artery measurements of diameter and blood flow were conducted, and WSS and WSS gradients were calculated. Circumferential straightening introduced areas of high WSS between stent struts that were absent in stented vessels of circular cross section. The area of vessel exposed to low WSS was dependent on the degree of circumferential vascular deformation and axial location within the stent. Stents with four vs. eight struts increased the intrastrut area of low WSS in vessels, regardless of cross-sectional geometry. Elevated WSS gradients were also observed between struts in vessels with polygonal cross sections. The results obtained using three-dimensional CFD models suggest that changes in vascular geometry after stent implantation are important determinants of WSS distributions that may be associated with subsequent neointimal hyperplasia.
- Published
- 2005
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263. Combined neural network model employing lyapunov exponents: internal carotid arterial disorders detection case.
- Author
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Fatma Guler N, Derya Ubeyli E, and Guler I
- Abstract
This paper illustrates the use of combined neural network models to guide model selection for diagnosis of internal carotid arterial disorders. The method presented in this study was directly based on the consideration that internal carotid arterial Doppler signals are chaotic signals. This consideration was tested successfully using the nonlinear dynamics tools, like the computation of Lyapunov exponents. Statistics were used over the set of the Lyapunov exponents in order to reduce the dimensionality of the extracted feature vectors. The first level networks were implemented for the diagnosis of internal carotid arterial disorders using the selected Lyapunov exponents as inputs. To improve diagnostic accuracy, the second level network was trained using the outputs of the first level networks as input data. The combined neural network models achieved accuracy rates which were higher than that of the stand-alone neural network models.
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- 2005
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264. Ergothioneine pretreatment protects the liver from ischemia-reperfusion injury caused by increasing hepatic heat shock protein 70.
- Author
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Bedirli A, Sakrak O, Muhtaroglu S, Soyuer I, Guler I, Riza Erdogan A, and Sozuer EM
- Subjects
- Alanine Transaminase antagonists & inhibitors, Alanine Transaminase blood, Animals, Aspartate Aminotransferases antagonists & inhibitors, Aspartate Aminotransferases blood, Cytoprotection, HSP70 Heat-Shock Proteins antagonists & inhibitors, Immunohistochemistry methods, L-Lactate Dehydrogenase antagonists & inhibitors, L-Lactate Dehydrogenase blood, Lipid Peroxidation drug effects, Liver pathology, Male, Malondialdehyde antagonists & inhibitors, Malondialdehyde blood, Rats, Rats, Wistar, Staining and Labeling, Survival Analysis, Antioxidants pharmacology, Ergothioneine pharmacology, HSP70 Heat-Shock Proteins metabolism, Liver drug effects, Liver Circulation, Reperfusion Injury metabolism, Reperfusion Injury pathology
- Abstract
Background: Reperfusion of the liver after ischemia induces the expression of the heat shock genes and the synthesis of the heat shock proteins (HSP). We studied the effects of the natural antioxidant ergothioneine (EGT) treatment on the expression of HSP70 in ischemic-reperfused (IR) liver., Methods: Adult male Wistar rats were randomly divided into three groups: Sham group given standard laboratory chow and water for 3 weeks followed by sham operation; Control group given standard laboratory chow and water for 3 weeks followed by liver IR injury; EGT group given standard laboratory chow supplementation l-ergothioneine (1.2 mg/kg/d body weight) administered by gavage and water for 3 weeks followed by liver IR injury. Ten rats from each group were killed to determine serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactic dehydrogenase (LDH), tissue malondialdehyde (MDA), HSP70 levels, and histologic changes at 30, 60, and 120 min of reperfusion, respectively. Survival was followed for 1 week., Results: IR caused significant increase in serum AST, ALT, LDH, and tissue MDA levels. As compared with the control group, animals treated with EGT experienced a significant decrease in serum AST, ALT, and LDH levels in all reperfusion periods. Tissue MDA levels in animals receiving EGT were significantly reduced as compared with control group at 30 min and 60 min after reperfusion. After ischemia, reperfusion caused a remarkable production of HSP70 in the control group. When the rats were pretreated with EGT, the levels of HSP70 increased significantly in their livers after reperfusion compared with the control group. Liver injury in the EGT-treated animals was lower to that in the control group. The 7-day survival rate was significantly improved (from 50% to 80%) by EGT pretreatment., Conclusion: HSP70 has been shown to induce tolerance against warm IR injury in rat livers. EGT pretreatment protects the liver from IR injury by over-expression of HSP and the subsequent suppression of lipid peroxidation.
- Published
- 2004
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265. Stent design properties and deployment ratio influence indexes of wall shear stress: a three-dimensional computational fluid dynamics investigation within a normal artery.
- Author
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LaDisa JF Jr, Olson LE, Guler I, Hettrick DA, Audi SH, Kersten JR, Warltier DC, and Pagel PS
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- Algorithms, Animals, Computer Simulation, Dogs, Graft Occlusion, Vascular physiopathology, Hemodynamics physiology, Models, Biological, Shear Strength, Arteries physiology, Prosthesis Design, Stents, Stress, Physiological physiopathology
- Abstract
Restenosis limits the effectiveness of stents, but the mechanisms responsible for this phenomenon remain incompletely described. Stent geometry and expansion during deployment produce alterations in vascular anatomy that may adversely affect wall shear stress (WSS) and correlate with neointimal hyperplasia. These considerations have been neglected in previous computational fluid dynamics models of stent hemodynamics. Thus we tested the hypothesis that deployment diameter and stent strut properties (e.g., number, width, and thickness) influence indexes of WSS predicted with three-dimensional computational fluid dynamics. Simulations were based on canine coronary artery diameter measurements. Stent-to-artery ratios of 1.1 or 1.2:1 were modeled, and computational vessels containing four or eight struts of two widths (0.197 or 0.329 mm) and two thicknesses (0.096 or 0.056 mm) subjected to an inlet velocity of 0.105 m/s were examined. WSS and spatial WSS gradients were calculated and expressed as a percentage of the stent and vessel area. Reducing strut thickness caused regions subjected to low WSS (<5 dyn/cm(2)) to decrease by approximately 87%. Increasing the number of struts produced a 2.75-fold increase in exposure to low WSS. Reducing strut width also caused a modest increase in the area of the vessel experiencing low WSS. Use of a 1.2:1 deployment ratio increased exposure to low WSS by 12-fold compared with stents implanted in a 1.1:1 stent-to-vessel ratio. Thinner struts caused a modest reduction in the area of the vessel subjected to elevated WSS gradients, but values were similar for the other simulations. The results suggest that stent designs that reduce strut number and thickness are less likely to subject the vessel to distributions of WSS associated with neointimal hyperplasia.
- Published
- 2004
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266. Grasper-assisted versus traditional laparoscopic splenectomy in the management of hematologic disorders.
- Author
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Bedirli A, Sozuer EM, Saglam A, Sakrak O, Guler I, Kucuk C, and Aritas Y
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- Adult, Equipment Design, Female, Humans, Male, Laparoscopy, Purpura, Thrombocytopenic, Idiopathic surgery, Splenectomy instrumentation, Splenectomy methods
- Abstract
Objective: To compare the technical benefits of grasper-assisted laparoscopic splenectomy (LS) with traditional LS., Methods: The study comprised 27 consecutive patients who were admitted to our hospital from 1998 to 2002 and underwent LS: 13 patients underwent traditional LS (group 1), and 14 had grasper-assisted LS (group 2)., Results: In both groups, the most common indication for LS was idiopathic thrombocytopenic purpura. There was no difference between the groups in the demographic characteristics of patients. All splenectomies were performed in the right semidecubitus position, using four or five trocars. Conversion to open surgery was required in one patient (7.7%) in group 1 and in one patient (7.1%) in group 2. Both conversions occurred during the initial 16 operations and no conversion occurred during the subsequent 11 operations. The mean operating time was significantly shorter for group 2 (132 minutes) than for group 1 (154 minutes) (P <.005). Mean estimated blood loss (201 vs. 282 mL) was also lower in group 2 than in group 1 (P <.05). The mean length of hospital stay was 3.3 days in group 1 and 2.4 days in group 2 (P >.05)., Conclusion: Grasper-assisted LS is both safe and feasible in patients with hematologic diseases. This technique can be preferred in order to grasp and position the spleen during the surgery.
- Published
- 2003
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267. Three-dimensional computational fluid dynamics modeling of alterations in coronary wall shear stress produced by stent implantation.
- Author
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LaDisa JF Jr, Guler I, Olson LE, Hettrick DA, Kersten JR, Warltier DC, and Pagel PS
- Subjects
- Adenosine pharmacology, Animals, Arteries drug effects, Blood Flow Velocity, Computer Simulation, Coronary Vessels drug effects, Dogs, Shear Strength, Vasodilator Agents pharmacology, Arteries physiopathology, Arteries surgery, Blood Vessel Prosthesis, Coronary Vessels physiopathology, Coronary Vessels surgery, Hemorheology methods, Models, Cardiovascular, Stents
- Abstract
Rates of coronary restenosis after stent implantation vary with stent design. Recent evidence suggests that alterations in wall shear stress associated with different stent types and changes in local vessel geometry after implantation may account for this disparity. We tested the hypothesis that wall shear stress is altered in a three-dimensional computational fluid dynamics (CFD) model after coronary implantation of a 16 mm slotted-tube stent during simulations of resting blood flow and maximal vasodilation. Canine left anterior descending coronary artery blood flow velocity and interior diameter were used to construct CFD models and evaluate wall shear stress proximal and distal to and within the stented region. Channeling of adjacent blood layers due to stent geometry had a profound affect on wall shear stress. Stagnation zones were localized around stent struts. Minimum wall shear stress decreased by 77% in stented compared to unstented vessels. Regions of low wall shear stress were extended at the stent outlet and localized to regions where adjacent axial strut spacing was minimized and the circumferential distance between struts was greatest within the stent. The present results depict alterations in wall shear stress caused by a slotted-tube stent and support the hypothesis that stent geometry may be a risk factor for restenosis by affecting local wall shear stress distributions.
- Published
- 2003
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268. Role of granulocyte-macrophage colony-stimulating factor on apoptosis induced by ischemia-reperfusion in the intestinal epithelium.
- Author
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Bedirli A, Soyuer I, Muhtaroglu S, and Guler I
- Subjects
- Animals, Camptothecin metabolism, Endodeoxyribonucleases metabolism, Ileum metabolism, Ileum pathology, Intestinal Mucosa metabolism, Jejunum metabolism, Jejunum pathology, Male, Malondialdehyde metabolism, Rats, Rats, Wistar, Reperfusion Injury metabolism, DNA Fragmentation drug effects, Granulocyte-Macrophage Colony-Stimulating Factor pharmacology, Intestinal Mucosa pathology, Reperfusion Injury drug therapy, Reperfusion Injury pathology
- Abstract
Background: To evaluate the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on ischemia-reperfusion-induced apoptosis in the intestinal epithelium., Methods: In this study, 50 male Wistar albino rats were used. After midline laparotomy superior mesenteric artery (SMA) was identified only in the sham group, while 60 min of ischemia and 2 h of reperfusion were performed in the control group. In the treatment groups, after 15, 30 and 60 min of ischemia, respectively, 1 microg/kg GM-CSF was administered subcutaneously, followed by 2 h of reperfusion. Malondialdehyde (MDA), campothecin (CAM), an indicator of DNA fragmentation, and histopathology were evaluated in the intestinal mucosa., Results: Tissue MDA levels were found significantly high in all groups at various times of ischemia and 2 h of reperfusion compared with the sham group (p < 0.001). Administration of GM-CSF following 60 min of ischemia caused a significant increase in the MDA levels compared with the control group (6430 +/- 725 vs. 4174 +/- 565 nmol/g protein for jejunum. 7576 +/- 618 vs. 4938 +/- 809 nmol/g protein for ileum, p < 0.05). Intestinal ischemia and reperfusion resulted in a significant increase in tissue CAM levels (p < 0.05). The highest CAM value was found in the group in which 60 min of ischemia and 2 h of reperfusion were performed (50 +/- 3.2 ng/ml for jejunum, 52.8 +/- 2.7 ng/mg for ileum). Compared with the control group, GM-CSF administration following 1 h of ischemia aggravated the tissue injury., Conclusions: Apoptosis was induced in the small intestine by ischemia-reperfusion. GM-CSF increased the apoptosis of intestinal epithelial cells and exacerbated mucosal injury due to ischemia-reperfusion., (Copyright 2003 S. Karger AG, Basel)
- Published
- 2003
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269. Stent implantation alters coronary artery hemodynamics and wall shear stress during maximal vasodilation.
- Author
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LaDisa JF Jr, Hettrick DA, Olson LE, Guler I, Gross ER, Kress TT, Kersten JR, Warltier DC, and Pagel PS
- Subjects
- Adenosine pharmacology, Anesthesia, Animals, Blood Flow Velocity drug effects, Blood Flow Velocity physiology, Coronary Circulation drug effects, Dogs, Female, Laser-Doppler Flowmetry instrumentation, Laser-Doppler Flowmetry methods, Male, Stress, Mechanical, Vascular Resistance physiology, Vasodilation drug effects, Vasodilator Agents pharmacology, Coronary Circulation physiology, Stents, Vasodilation physiology
- Abstract
Coronary stents improve resting blood flow and flow reserve in the presence of stenoses, but the impact of these devices on fluid dynamics during profound vasodilation is largely unknown. We tested the hypothesis that stent implantation affects adenosine-induced alterations in coronary hemodynamics and wall shear stress in anesthetized dogs (n = 6) instrumented for measurement of left anterior descending coronary artery (LAD) blood flow, velocity, diameter, and radius of curvature. Indexes of fluid dynamics and shear stress were determined before and after placement of a slotted-tube stent in the absence and presence of an adenosine infusion (1.0 mg/min). Adenosine increased blood flow, Reynolds (Re) and Dean numbers (De), and regional and oscillatory shear stress concomitant with reductions in LAD vascular resistance and segmental compliance before stent implantation. Increases in LAD blood flow, Re, De, and indexes of shear stress were observed after stent deployment (P < 0.05). Stent implantation reduced LAD segmental compliance to zero and potentiated increases in segmental and coronary vascular resistance during adenosine. Adenosine-induced increases in coronary blood flow and reserve, Re, De, and regional and oscillatory shear stress were attenuated after the stent was implanted. The results indicate that stent implantation blunts alterations in fluid dynamics during coronary vasodilation in vivo.
- Published
- 2002
- Full Text
- View/download PDF
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