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Biomedical subjects

M Yüksel

Publications and source records attributed to M Yüksel.

At least 19 recordsLinked to original sources
PubMed2002

Hepatobiliary scintigraphy for evaluating the hepatotoxic effect of halothane and the protective effect of catechin in comparison with histo-chemical analysis of liver tissue.

Halothane and its metabolites cause liver damage by decreasing liver blood flow and generating free-radical species. Catechin suppresses lipid peroxidation and increases enzyme activity, therefore it seems to be capable of protecting liver parenchyma against the direct toxic effect of halothane. The aim of this study was to investigate the role of hepatobiliary scintigraphy in detecting liver damage after halothane anaesthesia and the protective effect of catechin in comparison with histo-chemical analysis. Thirty rabbits, divided into three groups (A, controls; B, halothane; and C, catechin+halothane), were investigated. In group A no anaesthesia was administered. Group B only received halothane, while group C was pretreated with catechin and halothane anaesthesia was administered for 2 h. Dynamic scintigrams were taken for 60 min after injecting 99mTc-mebrofenin, and the time of peak uptake (TPU) and the time for half of the activity to clear from the liver (T(1/2)) were calculated. Rabbits were killed, and malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) levels were measured in hepatic tissue. The TPU and T(1/2) values of group A is significantly lower than in groups B and C (P<0.0002 and P<0.0002, respectively, for TPU; and P<0.0002 and P<0.0003, respectively, for T(1/2)). The TPU and T(1/2) values of group B were significantly higher than in group C (P<0.0003 and P<0.0003, respectively). The hepatic MDA level of group A was significantly lower than in groups B and C (P<0.0002 and P<0.0002, respectively). SOD, GSH-Px and CAT levels of group A were significantly higher than in groups B and C (P<0.0002, P<0.0001 and P<0.003, respectively, for group A vs group B; and P<0.0005, P<0.0002 and P<0.03, respectively, for group A vs group C). The MDA level of group B was significantly higher than that in group C (P<0.0002). SOD, GSH-Px and CAT levels of group B were significantly lower than in group C (P<0.0002, P<0.0002 and P<0.003, respectively). According to these results, we suggest that catechin protects liver parenchyma against the toxic effect of halothane and its metabolites, and that, compared to invasive histo-chemical analysis, hepatobiliary scintigraphy is a useful and alternative non-invasive method for detecting the protective effect of catechin on liver parenchyma after halothane anaesthesia.

Anesthesia↗
PubMed2001

Different kinds of reactive oxygen and nitrogen species were detected in colon and breast tumors.

Several studies have shown the involvement of reactive oxygen species (ROS; O2*-, hypochlorite, hydroxyl radical, hydrogen peroxide) in carcinogenesis. With certain pathologies, nitric oxide (NO) is formed and can interact with superoxide radical (O2*-) resulting in the propagation of the highly reactive species, peroxynitrite. In order to study the molecular mechanisms underlying the ability of reactive oxygen and nitrogen species (RONS) to mediate carcinogenesis, we have measured ROS, NO, and peroxynitrite content of cancerous tissues obtained from colon and breast carcinoma cases by chemiluminescence technique. All ROS were significantly increased in cancerous colon tissues with hypochlorite making the most important contribution and suggesting the role of inflammatory cells. NO was also increased and the peroxynitrite concentration was higher in cancerous samples. For breast carcinoma cases, only O2*- was significantly increased. Hypochlorite was not detected excluding the contribution of inflammatory cells. NO concentrations were not significantly different, therefore, ROS might originate by change in the redox state of the tissue.

Acridines↗
PubMed2001

Maternal serum levels of tumor necrosis factor-alpha and interleukin-2 receptor in threatened abortion: a comparison with normal and pathologic pregnancies.

OBJECTIVE: We evaluated tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) receptor levels in patients with threatened abortion and compared the levels with normal and pathologic pregnancies. DESIGN: A prospective, nonrandomized, case-control study. SETTING: Academic research setting. PATIENT(S): Twenty-two patients with threatened abortion, 18 patients with pathologic pregnancies, 20 healthy pregnant women, and 20 nonpregnant women. INTERVENTION(S): Maternal serum TNF-alpha and IL-2 receptor levels were measured with a solid-phase, two-site chemiluminescent enzyme immunometric assay method. MAIN OUTCOME MEASURE(S): TNF-alpha and IL-2 receptor levels. RESULT(S): The mean +/- SEM maternal serum IL-2 receptor level for patients with threatened abortion was 481.3 +/- 35.7 U/mL, compared with 426.5 +/- 22.4 U/mL in the normal pregnant group. There was no statistically significant difference in the mean +/- SEM serum TNF-alpha level between the patients with threatened abortion and those with normal pregnancies (16.1 +/- 2.7 pg/mL vs. 10.9 +/- 0.8 pg/mL). The mean +/- SEM maternal serum IL-2 receptor level was significantly higher in patients with pathologic pregnancies than in those with normal pregnancies (506.2 +/- 27.6 U/mL vs. 426.5 +/- 22.4 U/mL). The mean +/- SEM maternal serum TNF-alpha level was significantly higher in patients with pathologic pregnancies than in those with threatened abortion (39.2 +/- 9.5 pg/mL vs. 16.1 +/- 2.7 pg/mL) and normal pregnancies (39.2 +/- 9.5 pg/mL vs. 10.9 +/- 0.8 pg/mL). CONCLUSION(S): In comparison with normal pregnancies, maternal serum IL-2 receptor and TNF-alpha levels were not significantly increased in patients with threatened abortion with good outcome.

Abortion, Threatened↗
PubMed2001

Effect of mitochondrial electron transport chain inhibitors on superoxide radical generation in rat hippocampal and striatal slices.

In this study, we have compared the generation of superoxide radical in rat hippocampal and striatal slices in the presence of specific mitochondrial electron transport chain (ETC) inhibitors (complexes I and III) under control and depolarization conditions [incubation in artificial cerebrospinal fluid (ACSF) or depolarizing ACSF (dACSF), respectively]. Superoxide radical generation was increased in both ACSF- and dACSF-incubated hippocampal and striatal slices when rotenone and antimycin A were added to the incubation medium. The increase in superoxide radical was dependent on the concentration of ETC inhibitors under control, but not depolarization conditions. Rotenone was found to be more effective than antimycin A in producing superoxide radical from hippocampal and striatal slices. Our results also showed that hippocampal slices were more sensitive to ETC inhibitors compared with striatal slices. Thus, different regions of the brain seem to differ in their capacity to generate free radicals and vulnerability to oxidative stress conditions. This difference should be considered in developing therapeutic modalities against oxidative stress-related disorders and neurodegeneration.

Animals↗
PubMed2001

The side-effects of cardiopulmonary bypass on the lungs: changes in bronchoalveolar lavage fluids.

Although technical refinements have improved the safety of cardiac operations, postoperative dysfunction of lung and other organs occurs frequently after cardiopulmonary bypass (CPB). The aim of the present study was to search the aetiopathogenesis of pulmonary complications due to CBP. Ten patients with stable coronary artery disease, undergoing coronary artery bypass grafting (CABG) surgery, were included in the study. Forty bronchoalveolar lavage (BAL) fluid samplings were performed in the 10 patients. Samples were obtained at the following time periods: (1) preoperatively; (2) at the end of the first hour after anaesthetic induction; (3) at the conclusion of 30 min of crossclamp on CPB; and (4) at the conclusion of 20 h after the end of CPB, postoperatively. Cell contents of bronchoalveolar lavage fluid, alveolar macrophage viability, eosinophil cationic protein (ECP) levels and myeloperoxidase (MPO) concentrations were analysed in each bronchoalveolar lavage fluids. While the percentage of preoperative macrophages was 85.90% and the percentage of preoperative neutrophils was 2.40%, they were 77.00% and 11.30% in the postoperative samples, respectively. Mean alveolar macrophage viability was 96.20% preoperatively and 90.40% in the postoperative period. Preoperative eosinophil cationic protein mean concentration was < 2 microg/l and mean response value (RV) was 28.80. Preoperative mean myeloperoxidase concentration was 7.66 ng/ml. Postoperative eosinophil cationic protein mean response value was 63.40 and mean myeloperoxidase concentration was 59.25 ng/ml. There were significant differences between third and final samples with regard to both neutrophil percentages (p = 0.028) and MPO levels (p = 0.005). While the preoperative mean PaO2 value was 89.39 mmHg and mean SaO2 value was 97.12%, they were calculated in the postoperative arterial blood specimens of patients, without inhaling O2, as 65.31 mmHg and 93.84%. These changes between blood gas analyses reflect the impairment of the lungs (p = 0.009 and p = 0.007, respectively). Neither alveolar macrophage viability nor ECP levels changed significantly between consecutive periods. However, when the results of the first and fourth samples were compared, we saw the cumulative effects of CPB, in that alveolar macrophages lost their viability and ECP mean RVs rose. These changes were statistically significant (p = 0.027 and p = 0.013, respectively). However, postoperative ECP levels were not like those found in a patient with asthma. Also, changes between alveolar macrophage percentages (p = 0.028), between neutrophil percentages (p = 0.036) and between MPO concentrations (p = 0.005) were statistically significant. Again, changes in neutrophil percentages between first and final samples correlated with changes in MPO levels between same periods (r = 0.657, p = 0.039).

Adult↗
PubMed2001

Maternal serum tumor necrosis factor-alpha in patients with preterm labor.

OBJECTIVE: To evaluate maternal serum tumor necrosis factor-alpha (TNF alpha) levels in patients with preterm labor without clinical signs of chorioamnionitis and to compare these with levels in nonlaboring controls. STUDY DESIGN: The study group consisted of 44 patients with a singleton pregnancy admitted to our department with the diagnosis of preterm labor between 26 and 36 weeks' gestation. The control group consisted of 25 healthy consecutive patients with a singleton pregnancy without preterm contractions who were seen for routine antenatal visits. Maternal serum TNF alpha was measured using a solid-phase, two-site chemiluminescent enzyme immunometric assay method, and levels were compared in patients with preterm labor and nonlaboring controls. RESULTS: The median maternal serum TNF alpha level for patients with preterm labor was 29.4 pg/mL (range, 12.3-173) as compared with 23 pg/mL (range, 11.9-62.7) in the control group (P = .031). Among 44 patients with preterm labor, 14 (32%) delivered within one week of admission. The median maternal serum TNF alpha level was significantly higher in patients who delivered within one week than in those who delivered after one week and controls (71.3 pg/mL [range, 28-173]) versus 22 pg/mL (range, 12.3-86) versus 23 pg/mL (range, 11.9-62.7) (P < .0001). CONCLUSION: TNF alpha was elevated in patients with preterm labor, suggesting a role for maternal serum TNF alpha in its initiation.

Adult↗
PubMed2001

Neurologic complications after deep hypothermic circulatory arrest: types, predictors, and timing.

To determine the nature of neurologic dysfunction after deep hypothermic circulatory arrest during aortic arch surgery, we reconsidered the cases of 154 patients who had undergone aortic arch surgery (either of the ascending or transverse aorta, or both) between November 1993 and July 1999. Temporary postoperative neurologic dysfunction was seen in 9 patients (5.8%), and another 3 patients (1.9%) experienced stroke. Patients with temporary neurologic dysfunction had no new infarct and were discharged home with no residual symptoms. Computed tomographic scans revealed that 2 patients with stroke had multiple infarcts in the brainstem, and the 3rd had bilateral border-zone infarcts. The patients with brainstem infarcts died on postoperative days 7 and 15, and the patient with border-zone infarct was discharged home with no symptoms 3 months after surgery. Univariate analysis revealed that patients with neurologic deficits had significantly higher rates of history of hypertension, concomitant coronary artery bypass grafting, cardiac ischemia times longer than 90 minutes, and chronic renal failure. A multivariate logistic regression analysis revealed that the significant preoperative variables associated with neurologic deficits were a history of hypertension and a cardiac ischemia time longer than 90 minutes. Deep hypothermic circulatory arrest is a safe and useful technique for protection of the brain during surgery for complex aortic problems. In future, some patients at extreme risk for perioperative neurologic complications might be offered novel neuroprotective agents, in combination with deep hypothermia.

Adult↗
PubMed2001

Monitoring the chemotherapeutic response in primary lung cancer using 99mTc-MIBI SPET.

Prediction and evaluation of the response to chemotherapy (CTx) are important for the correct and cost-effective treatment of patients with primary lung cancer. Although fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is accepted as the most useful and accurate nuclear medicine technique for this purpose, its expense and limited availability restrict its use. Compared with PET agents, technetium-99m methoxyisobutylisonitrile (MIBI), which is used in nuclear oncology, is cheaper and available in any nuclear medicine clinic. With this in mind, in this study we aimed to evaluate the role of 99mTc-MIBI in monitoring the chemotherapeutic response in primary lung cancer. Twenty patients with primary lung cancer underwent 99mTc-MIBI single-photon emission tomography (SPET) at 15 min (early) and 3-4 h (delayed) after injection of the tracer. All patients underwent 99mTc-MIBI SPET study twice: before and after the 3rd cycle of CTx. Patients were divided into two groups, responders [R(+), n=10] and nonresponders [R(-), n=10], according to the change in tumour size on CT scan taken 2 weeks after the last cycle of the CTx. From the SPET images early and delayed tumour/lung ratios (ER and DR) were obtained before and after CTx. In the R(+) group, ER and DR decreased significantly after CTx, from 3.28+/-1.55 to 1.78+/-0.72 (P<0.04) and from 3.23+/-1.55 to 2.0+/-0.88 (P<0.05), respectively. However, in the R(-) group, while ER showed a slight and statistically insignificant increase after CTx (from 2.51+/-1.23 to 2.65+/-1.86), DR increased significantly, from 2.74+/-1.37 to 3.27+/-2.31 (P<0.03). The percentage decreases in ER and DR in the R(+) group after CTx was significantly higher than that in the R(-) group: 34.36%+/-26.7% vs -13.78%+/-27.58% (P<0.0002) and 29.45%+/-25.23% vs -18.58%+/-20.51% (P<0.0005), respectively. Using a decrease of > or =10% as a threshold for monitoring the chemotherapeutic response, 99mTc-MIBI had a sensitivity of 90% and a specificity of 100%. We found a positive correlation in 14 patients between ER and DR and survival: r=0.6754 and P=0.008, and r=0.5755 and P=0.031, respectively. Our results suggest that 99mTc-MIBI might be used in routine practice to monitor the chemotherapeutic response in patients with primary lung cancer, especially when PET is not available.

Adult↗
PubMed2000

Rudolf Nissen's years in Bosphorus and the pioneers of thoracic surgery in Turkey.

Rudolph Nissen is one of the most distinguished pioneers in thoracic surgery, well known for his pneumonectomy operation performed for the first time in surgical history. He migrated to Istanbul like most of his contemporary colleagues, avoiding the fascist regime in Germany in the 1930s. He was enthusiastically welcomed in Turkey and appointed as the Chief of the First Surgery Clinic in Istanbul University in 1933. He worked with discipline and in cooperation with his Turkish colleagues, such as Ahmed Burhaneddin Toker, Fahri Arel, Dervis Manizade, and others, who were to become the leading authorities of general thoracic surgery in Turkey. During his 6 years of residence and working in Istanbul, he contributed highly to the practice of general and thoracic surgery. He had to leave for the United States in 1939 for treatment of his lung abscess due to a retained bullet from World War I. He stayed in New York and later in Basel until his death. He was presented an honorary professorship from Hacettepe University, Ankara in 1973.

Eponyms↗
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↗