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Biomedical subjects

M Yüksel

Publications and source records attributed to M Yüksel.

At least 37 records · Page 2Linked to original sources
PubMed2000

The effect of aminophylline administration on 99mTc-MIBI lung and liver uptake in patients with or without myocardial ischemia.

This work aims to analyze the influence of aminophylline in the pulmonary and hepatic uptake of 99mTc-methoxyisobutil isonitrile (99mTc-MIBI). 72 patients were studied and a myocardial perfusion (MPS) single photon emission computed tomography (SPECT) with 99mTc-MIBI was carried out after the administration of dipyridamole. According to the MPS, the patients were classified into 2 groups: Group A: 45 patients without myocardial ischemia and Group B: 27 with ischemia. Each group was divided into 2 subgroups according to whether they had (I) or had not (II) received intravenous aminophylline. The dipyridamole was administered for 4 minutes at a dose of 0.56 mg/kg. If the patients presented any complication, intravenous aminophylline was administered. At 30 minutes p.i., planar images were obtained during a scintigraphy in the interior projection after the injection of 99mTc-MIBI. The regions of interest in the heart, hepatic cupula, and most active area of the left lung were outlines and the activity rates were calculated: lung/heart (LHR) and liver/heart (LivHR). No statistically significant differences were observed in the uptake of 99mTc-MIBI between subgroups I and II. However, the LHR rates in both subgroups were significantly lower in the patients with normal myocardial perfusion than in the patients with ischemia: LHR group A1 vs B1: 0. 32 +/- 0.08 vs 0.36 +/- 0.06, p = 0.03; group AII vs BII 0.31 +/- 0. 07 vs 0.35 +/- 0.07, p = 0.01 respectively. In conclusion, the administration of aminophylline, after the infusion of dipyridamole for MPS, does not modify the pulmonary or hepatic uptake of 99mTc-MIBI.

Adult↗
PubMed2000

The role of hepatobiliary scintigraphy in the evaluation of the protective effects of dimethylsulphoxide in ischaemic/reperfusion injury of liver.

Liver ischaemia may lead to parenchymal damage depending on the duration of the ischaemia. Dimethylsulphoxide (DMSO), a well-known radical oxygen scavenger, is a protective agent against ischaemia/reperfusion injury. In this study we aimed to investigate the role of hepatobiliary scintigraphy (HBSc) in detecting the protective effect of DMSO. Eighteen rabbits, in three groups of six, were injected with 37 MBq technetium-99m-mebrofenin via the ear veins. Dynamic scintigrams were taken for 60 min (1 frame/min). In group A, HBSc was performed without any surgery. In groups B and C the Pringle manoeuvre (PM) was applied for 30 min, and tissue specimens for electron microscopy were taken from the liver parenchyma 5 min after the end of the PM. In addition, in group C 1 g/kg DMSO was injected into each rabbit 5 min before application of the PM. HBSc was then performed in groups B and C. From the dynamic images time-activity curves (TACs) were obtained for each group, and the time of peak uptake (TPU) and time for half of the activity to clear from the liver (T1/2) were calculated. The TPU and T1/2 of group B were significantly longer than those of groups A and C (P<0.0005 and P<0.005 for TPU, and P<0.0005 and P<0.02 for T1/2, respectively). The TPU and T1/2 of group C were significantly longer than those of group A (P < 0.005 and P < 0.02, respectively). While the electron microscopic images in group C showed reversible changes, those in group B showed both irreversible and reversible changes. The electron microscopic findings of groups B and C confirmed the scintigraphic findings. In conclusion, HBSc might be used as a practical quantitative method for detecting the protective effects of DMSO. However, its clinical value should be evaluated by further studies with human subjects.

Aniline Compounds↗
PubMed2000

Endothelin-1-induced PMN infiltration and mucosal dysfunction in the rat small intestine.

The objectives of this study were to characterize the effects of endothelin (ET)-1 on intestinal mucosal parameters and to assess the contribution of polymorphonuclear leukocytes (PMNs), intercellular adhesion molecule-1 (ICAM-1), and a platelet-activating factor (PAF) to the mucosal dysfunction induced by ET-1. Different concentrations of ET-1 (100, 200, and 400 pmol/kg) were infused into the superior mesenteric artery for 10 min, and tissue samples were obtained 30 min after terminating the infusion. ET-1 administration significantly elevated tissue myeloperoxidase activity, plasma carbonyl content, and tissue chemiluminescence intensity, indicating that ET-1 produces PMN infiltration and oxidant stress. Blood-to-lumen clearance of (51)Cr-EDTA significantly increased after ET-1 infusion (400 pmol/kg). Monoclonal antibodies against ICAM-1 (1A29, 2 mg/kg), antineutrophil serum, and PAF antagonist (WEB-2086, 10 mg/kg) attenuated the mucosal barrier dysfunction induced by ET-1. Overall, our data indicate that ET-1 causes PMN accumulation, oxidant stress, and mucosal dysfunction in the rat small intestine and that ET-1-induced mucosal dysfunction involves a mechanism that includes a role for PMNs, ICAM-1, and PAF.

Animals↗
PubMed2000

Tracheobronchopathia osteochondroplastica.

Tracheobronchopathia osteochondroplastica (TO) is a rare disorder with unknown aetiology. We report one case of TO in a patient with non-Hodgkin pulmonary lymphoma and benign epidermal and trichylemmal cysts on the periorbital region and scalp. To the authors' knowledge, the coincidence of these processes has never been described before. The case was evaluated with conventional X-ray, computed tomography, magnetic resonance imaging, fibre-optic bronchoscopy with 2 months interval, histopathological evaluation, Tc-99 m MDP bone scintigraphy and microbiological studies including PCR testing of bronchial biopsy and lavage specimens for Mycobacterium tuberculosis. Additionally, case reports of TO in the Turkish literature are summarized.

Aged↗
PubMed2000

A connecting branch between the musculocutaneous nerve and the median nerve.

We report here a connecting branch between the musculocutaneous and the median nerves in a 42 years old male cadaver. The connecting branch was 8 cm in length and 3 mm in width. One of the brachial veins and the brachial artery were located between the roots of the median nerve and the second brachial vein was present between the connecting branch and the median nerve. These kinds of variations may effect the venous return and may cause edema in the upper extremities. Additionally, variations of these nerves have an importance during operations of this region.

Adult↗
PubMed1999

The effect of antioxidant therapy on colonic inflammation in the rat.

Under normal physiological conditions, chemical and antioxidant defenses protect tissues from the damaging effects of reactive oxygen metabolites (ROM). It has been proposed that ROMs are involved in the development of tissue injury in many inflammatory diseases and also in patients with colitis. In the present study we aimed to investigate the effects of antioxidant therapy on the extent of colonic inflammation and ROM levels in the injured tissues in a trinitrobenzene sulfonic acid-induced colitis model in the rat. Sprague-Dawley rats were pretreated with the antioxidants superoxide dismutase (30,000 U/kg s.c.) or catalase (400,000 U/kg s.c.) prior to induction of colitis and they were decapitated 24 h (acute group) or 6 days (chronic group) after the induction of colitis (each group consists of eight to ten rats). Pretreatment with the antioxidants reduced the macroscopic damage score significantly in both acute and chronic groups compared with untreated colitis groups, whereas they reduced the microscopic damage score and colonic wet weight only in the chronic group. The chemiluminescence assay - a technique to assess the presence of reactive oxygen species in the tissues - values of the groups pretreated with the antioxidants showed a tendency to decrease compared with the untreated colitis group, but they were not statistically significant. Based on these findings, pretreatment with the antioxidants superoxide dismutase or catalase has beneficial effects on the extent of colonic inflammation, particularly in the chronic period, and this may support the importance of antioxidant therapy to reduce the severity of inflammatory bowel disease in humans.

Animals↗
PubMed1999

Comparison of omentum, pleura and diaphragm for tracheal autograft survival in rats.

Pleura, diaphragm, pericardial fat pad, intercostal muscles and omentum can be used to protect and revascularize the bronchial suture line. To compare the efficiency of pleura, diaphragm and omentum, an experimental study was designed. Heterotopic tracheal autotransplantation was performed in 15 rats. Animals were divided into three groups; omentum, diaphragm and pleura. Tracheal Segment Necrosis Scoring System was used for pathologic examinations. Pleural and diaphragmatic groups showed the least necrosis and there was significant statistical difference among these groups and omental group (P < 0.05). Our study showed that pleura and diaphragm could be used as safely as omentum for protection and survival of bronchial suture lines.

Analysis of Variance↗
PubMed1999

Thorax high resolution computerized tomography findings in asthmatic children with unusual clinical manifestations.

BACKGROUND: It has been consistently observed in high resolution computerized tomography (HRCT) scans that asthmatic patients manifest more abnormalities related to airways remodeling than do normal subjects. OBJECTIVE: To find the underlying abnormalities in the lungs of asthmatic children with unusual manifestations. METHOD: Asthmatic children not responding as expected to inhaled steroid therapy with or without localized permanent or temporary recurrent auscultation findings (rales) were evaluated with chest radiographs and HRCT scans. Bronchoscopy was performed on the ones with localized rales. RESULTS: The sample consisted of 16 asthmatic children (6 girls and 10 boys, mean age = 7.75+/-4.43 years). Chest radiograph abnormality rate was 44% and the thorax HRCT scan abnormality rate was 75% (56% fibrotic retractions, 38% atelectasis, 19% bronchiectasis, and 19% bronchial wall thickening). Two patients with localized permanent rales and with right middle lobe (RML) atelectasis in HRCT scan underwent bronchoscopy which revealed RML syndrome due to mucus plugging in one and lymph node pressure in the other. In one patient with localized temporary recurrent rales and major bronchiectasis in HRCT scan, bronchoscopy revealed bronchitis. The patient with RML syndrome due to mucus plugging required lobectomy. CONCLUSION: We conclude with this experience that thorax HRCT scanning may be a helpful adjunct in the evaluation of an asthmatic children with atypical clinical findings.

Anti-Asthmatic Agents↗
PubMed1999

Local gene delivery: arterial thrombosis model for endothelial cell-targeted thrombolytic gene therapy research.

The authors describe a rabbit arterial thrombosis model that employs vessel division followed by microsurgical anastomosis and transluminal sutures, to reliably induce thrombus formation in the common femoral artery (CFA). Using two objective measures, "evacuation/refill" evaluation of patency and computer-aided histomorphometric analysis of the thrombus area, thrombus formation was confirmed and characterized in the model at both short- and long-term observation time-points. In addition, a gene delivery method was developed in the CFA that employs an adenoviral vector solution injected through the inferior epigastric artery (IEA). Using this method, a marker transgene (beta-galactosidase) was delivered to endothelial cells locally and without trauma. By subsequently performing beta-galactosidase staining, effective endothelial transfection was demonstrated simultaneously with endothelial viability, with preserved endothelial synthetic function in the immediate environment of the occluding thrombus. The results suggest that these two techniques can be used together in one model, to effectively introduce a foreign therapeutic transgene into endothelial cells and to evaluate the effect of the expressed protein product in a consistent in vivo thrombosis system. This combined model may be used as one of several assays of efficacy in future endothelial cell-targeted thrombolytic/antithrombotic vascular gene therapy research.

Adenoviridae↗
PubMed1999

The effects of free oxygen radical scavenger and platelet-activating factor antagonist agents in experimental acute pancreatitis.

This study was done to evaluate the possible preventive effects of reactive oxygen species (ROS) scavenger agent desferrioxamine (DFX) and platelet-activating factor (PAF) antagonist agent ginkgo biloba (GB) in an experimental acute pancreatitis model. Seventy-eight CD-1 mice were divided into six groups consisting of 10-13 mice. Induction of pancreatitis was achieved by cerulein injection in groups 2-5. The first group was control, whereas DFX and GB were used alone or in combinations as preventive agents in groups 3-5. DFX or GB were injected to the mice in groups 6 and 7 to evaluate any toxic effect. The assessment of the pancreatic edema and inflammation, the measurement of the amylase and the pancreatic weight and the measurement of the pancreatic tissue oxidative capacity by chemiluminescence method were the parameters to evaluate pancreatitis. Although the results indicate DFX and GB alone or in combinations have significant preventive roles, this was not a complete prevention.

Acute Disease↗
PubMed1999

Role of nitric oxide in indomethacin-induced gastric mucosal dysfunction in the rat.

The present study was undertaken to explore the role of nitric oxide (NO) in the pathogenesis of experimental non-steroidal anti-inflammatory drug (NSAID)-induced gastropathy. We assessed the role of NO inhibition and donation in indomethacin-induced gastric mucosal dysfunction. The stomach was perfused with vehicle (control) for 20 min, followed by indomethacin (10 mg ml-1 in 1 25 % sodium bicarbonate, pH 8 4) for 120 min. NG-nitro-L-arginine methyl ester (L-NAME, 5 and 10 mg kg-1, I.V. bolus), L-arginine, D-arginine (100 mg kg-1 I.V. bolus, 10 mg kg-1 h-1, 2 h infusion) and the NO donor glyceryl trinitrate (GTN) were given at the same time (20, 40 and 80 microg kg-1 min-1, 15 min infusion) as perfusion with indomethacin was started. Epithelial permeability was quantified by measuring blood-to-lumen clearance of 51Cr-labelled EDTA. Indomethacin caused a 20-fold increase in 51Cr-EDTA leakage compared with that of the control group. Treatment with L-NAME or L-arginine did not affect the indomethacin-induced alterations in mucosal permeability. Administration of GTN (20 microg kg-1 min-1) significantly reduced the indomethacin-induced mucosal dysfunction. By contrast, higher doses of GTN (80 microg kg-1 min-1) exacerbated epithelial dysfunction induced by indomethacin. Elevated levels of carbonyls and myeloperoxidase (MPO) observed after indomethacin administration were significantly reduced, to the control values, when GTN (20 microg kg-1 min-1) was administered along with indomethacin. These data suggest that NO from exogenous sources can exert a dual action on the integrity of the gastric mucosa challenged by indomethacin. Low doses of GTN can prevent mucosal dysfunction induced by indomethacin, while higher doses of GTN may exacerbate the increases in epithelial permeability.

Animals↗
PubMed1999

Diagnosis and treatment of concomitant aortic and coronary disease: a retrospective study and brief review.

Coronary arteriosclerosis seriously complicates the surgical treatment of aortic diseases. The aim of our retrospective study was to determine the incidence of coronary artery disease among our surgical patients in treatment for aortic dissection or aneurysm, and to determine whether coronary intervention before aortic surgery appears to affect outcomes. Between 1 January 1993 and 1 March 1998, our center treated 253 patients for aortic dissection or aneurysm. We examined these cases retrospectively for information on diagnostic and treatment methods, both for the aortic lesions and for concomitant coronary arteriosclerosis. Aortic dissection had been detected in 86 (33.9%) patients and aortic aneurysm in 167 (66.1%). Coronary angiography was performed to search for concomitant coronary artery disease in 29 (33.8%) patients with dissection and in 112 (67.1%) patients with aneurysm; of these, 11 (12. 7%) and 54 (32.3%), respectively, were found to have coronary disease. Among 43 patients with abdominal aortic aneurysm in whom coronary angiography was performed, concomitant coronary disease was detected in 36 (83.7%). Coronary artery bypass surgery was performed in 10 patients who had dissection and in 30 patients who had aneurysm; percutaneous transluminal coronary angioplasty was performed in 7 patients who had aneurysm. Perioperative mortality rates in the dissection and aneurysm groups, overall, were 23.2% and 13.8%, respectively Unfortunately, the prospective, random clinical study that would be necessary to prove the case for or against preoperative coronary angiography among subsets of patients in need of aortic repair would raise ethical questions, given the strength of the information already in our possession, gathered by less formal methods. Our study reinforces existing evidence that preoperative angiography can reduce mortality and morbidity in the elective repair of aortic aneurysm, especially thoracic or abdominal aneurysm. However, angiography should not be performed routinely in cases of aortic dissection and should be withheld in cases of type A dissection.

Adolescent↗
PubMed1999

Proximal clamping levels in abdominal aortic aneurysm surgery.

In the surgical treatment of abdominal aortic aneurysm, the single proximal cross-clamp can be placed at 3 alternative aortic levels: infrarenal, hiatal, and thoracic. We performed this retrospective study to evaluate the advantages and disadvantages of the 3 main aortic clamping locations. Eighty patients presented at our institution with abdominal aortic aneurysms from March 1993 through May 1998. Fifty of these patients had intact aneurysms and underwent elective surgery, and 30 had ruptured aneurysms that necessitated emergency surgery. Proximal aortic clamping was applied at the infrarenal level in 24 patients (22 from the intact aneurysm group, 2 from the ruptured group), at the hiatal level in 34 patients (22 intact, 12 ruptured), and at the thoracic level (descending aorta) via a limited left lateral thoracotomy in 22 patients (6 intact, 16 ruptured). Early mortality rates (within 30 days) were 4% (2 of 50 patients) among patients with intact aneurysms and 40% (12 of 30 patients) among those with ruptured aneurysms. In the 2 patients from the intact aneurysm group, proximal aortic clamps were applied at the hiatal level. In the ruptured aneurysm group, proximal aortic clamps were placed at the thoracic level in 10 patients, the infrarenal level in 1, and the hiatal level in 1. According to our study, the clinical status of the patient and the degree of operative urgency--as determined by the extent of the aneurysm--generally dictate the proximal clamp location. Patients who present with aneurysmal rupture or hypovolemic shock benefit from thoracic clamping, because it restores the blood pressure and allows time to replace the volume deficit. Infrarenal placement is advantageous in patients with intact aneurysms if there is sufficient space for the clamp between the renal arteries and the aortic aneurysm. In patients with juxtarenal aneurysms, hiatal clamping enables safe and easy anastomosis to the healthy aorta. Clamping at this level also helps prevent late anastomotic aneurysm formation, which is frequently encountered after inadvertent anastomosis of the graft to a diseased portion of the aorta. Further studies are needed in order to confirm these results.

Adult↗
PubMed1998

Low dose MK-801 protects against iron-induced oxidative changes in a rat model of focal epilepsy.

We have used chemiluminescence measurements to examine the relationship between free radical formation and excitotoxicity in a post-traumatic epilepsy model. For this purpose, seven days after injecting iron in rat brain cortices, we measured luminol- and lucigenin-enhanced chemiluminescence in different brain regions (ipsilateral cortex, contralateral cortex, hypothalamus and hippocampus). In all brain regions (except contralateral cortices) both luminol- and lucigenin-enhanced chemiluminescence were increased in iron-injected group compared to saline-injected control group. These increases returned to control values in iron-injected rats pretreated with MK-801. Our results suggest that both free radicals and excitatory amino acids play important roles in the development of post-traumatic epilepsy and that MK-801 has protective effects against iron-induced chemiluminescence formation.

Analysis of Variance↗