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S Yavuzer

Publications and source records attributed to S Yavuzer.

At least 19 recordsLinked to original sources
PubMed2005

Does antinerve growth factor affect isolated ileal contractility in rat?

This study investigates the effects of antinerve growth factor (anti-NGF) application on isolated ileal contractility in the rat. For this purpose, rats were divided into four groups. The control animals (n=8) received only intraperitoneal injection of an isotonic NaCl solution (i.p). Anti-NGF was daily administered intraperitoneally at the dose of 1 ng/g level in the first experimental group (n=8), and at doses of 10 ng/g (n=7) and 40 ng/g (n=7) in the second and third experimental groups, respectively. Seven days after the injections rats were sacrificed and ileum segments were isolated. Responses to acetylcholine (ACh) were evaluated by using standard Tyrode, double-calcium Tyrode and calcium-free Tyrode solutions. The average peak amplitude of ACh-induced contractions recorded in standard Tyrode solution was significantly decreased in all three experimental groups as compared to the control group (p 0.05). When double-calcium Tyrode solution was used as the perfusion medium, the responses to ACh were also lower in all anti-NGF applied groups as compared to its control group (p 0.05). Our results showed that the application of anti-NGF reduced the contractile responses of the rat isolated ileum apparently by decreasing the calcium influx from the extracellular medium.

Animals↗
PubMed2003

Female and male differences in the survival of patients undergoing resection for lung cancer.

OBJECTIVE: In recent years much attention has been focused on the rapidly increasing incidence of primary lung cancer in women. The aim of this study was to determine gender differences in patients treated surgically for lung cancer. METHODS: We performed a retrospective review of patients who had lung resection for primary lung cancer from January 1994 to December 1998. RESULTS: There were 530 men and 42 women. Women were younger than men (55.6 +/- 10 versus 57 +/- 9.9). The difference was not statistically significant (p = 0.9). The mean cigarette consumption was greater in men than in women (p < 0.001). We observed a higher operative morbidity and mortality rate in men compared to women (p < 0.05). Men had more squamous cell carcinoma (61.7%). In female patients, squamous cell cancer and adenocarcinoma were found with almost the same incidence (35.7% versus 33.3%). There was a significant difference in the distribution of cell types (p < 0.001). Pathologic stages for women were; I = 38.2%, II = 21.4%, IIIa = 21.4%, IIIb = 9.5%, IV = 9.5% and for men; I = 40.4%, II = 26.6%, IIIa = 24%, IIIb = 6%, IV = 3%. There was no significant difference in the stage distribution between genders (p = 0.2). Median survival for female and male patients were 38 +/- 9.2 and 35 +/- 3.2 months. Female patients' survival was longer than male patients but the difference was not statistically significant (p > 0.05). CONCLUSIONS: This study emphasizes sex differences in cigarette consumption, operative mortality and the distribution of cell types of patients with primary lung cancer. These initial results should strongly encourage additional studies in different countries on the interaction between sex and lung cancer characteristics to improve clarity.

Adenocarcinoma↗
PubMed2002

Effect of submaximal and incremental upper extremity exercise on platelet function and the role of blood shear stress.

INTRODUCTION: Platelets are involved in the pathogenesis of atherosclerosis. Although physical exercise is recommended to prevent atherosclerosis, the effect of exercise on platelet function and the underlying mechanisms of these effects are not completely understood. Accordingly, we aimed to examine the effect of different intensities acute arm exercises on platelet function. In addition, we evaluated the effect of lipid peroxidation and fluid shear rate on platelet response. MATERIALS AND METHODS: Twenty four healthy sedentary male volunteers aged 18-24 years performed submaximal and incremental exercises by upper extremity ergometer. The shear rate in the right artery was measured by Power Doppler Ultrasound (US) at rest and immediately after exercise. Pre and postexercise maximum intensities of ADP and collagen-induced platelet aggregation were measured using the impedance technique. Bioluminescent detection of thrombin-induced platelet ATP release and measurement of thromboxane B(2) (TxB(2)) levels (as a marker of thromboxane A(2) (TxA(2)) formation) by enzyme-linked immunoassay were performed before and after exercise. RESULTS AND CONCLUSION: Shear rate increased after both submaximal and incremental exercise. Collagen-induced platelet aggregation increased after submaximal exercise, while ADP-induced aggregation and thromboxane B(2) levels did not alter with this protocol. Incremental exercise caused increased collagen and ADP-induced platelet aggregation and thromboxane B(2) levels. Neither of the protocols altered platelet ATP release. It was shown that acute upper extremity exercise increased platelet aggregation, without an increase in platelet release. Collagen-induced signalling pathways were more sensitive than those induced by ADP. The increase in thromboxane B(2) after incremental exercise implied increase in thromboxane A(2) formation and lipid peroxidation. Despite a significant correlation between platelet aggregation and thromboxane B(2) levels at rest, we found no clear-cut relationship between thromboxane A(2) formation, blood shear rate and platelet response to exercise.

Adenosine Diphosphate↗
PubMed2001

Management of esophageal perforation.

Despite recent advances in thoracic surgery, the management of esophageal perforation remains problematical and controversial. Thirty-one patients were treated for an esophageal perforation between 1986 and 1998. The esophageal perforation was iatrogenic in 25 cases, spontaneous in 2, traumatic in 2, and caused by a tumor and tuberculous lymphadenitis in 2 patients. There were 10 cervical, 19 thoracic, and 2 abdominal perforations. The interval from perforation to operation was less than 24h in 12 patients and more than 24h in 19 patients. The surgical procedures included a primary repair in 12 patients, a resection in 8, and conservative treatment with minor surgical approaches in 11. The mortality rate was 20% (4/20 patients) in the surgical treatment group and 45.5% (5/11 patients) in the conservative treatment with minor surgery group. The overall mortality was 29% (9/31 patients). The prognosis is thus concluded to depend on the cause and location of the perforation, the presence of underlying esophageal diseases, and the surgical procedure chosen.

Adolescent↗
PubMed2001

Possible effects of antioxidant status on increased platelet aggregation in childhood iron-deficiency anemia.

BACKGROUND: Alterations in platelet function and antioxidant status in children with iron-deficiency anemia (IDA) have been reported previously. The present study was performed to better understand possible interactions between these two systems. METHODS: Erythrocyte superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activity and platelet function were evaluated in 15 children (aged 1 1/2-15 years) with IDA. The antioxidant enzyme activity was determined spectrophotometrically. Platelet aggregation and secretion studies were performed using impedance and bioluminescence methods, respectively. Ten age-matched healthy children were included as a control group. RESULTS: There were no differences in SOD and CAT activities between patients and controls. However, GSH-Px activity was significantly lower in the iron-deficient children. Platelet aggregation responses to collagen and ADP were also significantly higher in iron-deficient children than in controls. CONCLUSIONS: Decreased antioxidant defense in IDA may cause increased oxidant stress, which, in turn, may result in a tendency towards platelet aggregation.

Adolescent↗
PubMed2001

Surgical treatment of pulmonary hydatid cysts in children.

PURPOSE: Ten years' experience is analyzed in pediatric patients with pulmonary hydatid cysts. METHODS: Between 1990 and 2000, 33 pediatric patients (2 to 15 years of age) with pulmonary hydatid cysts were operated on in Department of Thoracic Surgery in Ankara University School of Medicine. There were 17 girls and 16 boys. RESULTS: Twenty-three cases presented as a solitary lung cyst, whereas the remaining 10 were found to have multiple cysts in one or both lungs. Cystotomy and capitonnage were performed in 25 patients, cystotomy was done in 6 patients, and only 2 patients underwent the wedge resection. The authors used no scoliocidal agent in our approach. There was no operative mortality. Recurrence after operation was seen in one patient. CONCLUSION: Pulmonary hydatid cysts in children can be treated successfully by cystotomy and capitonnage or only cystotomy. J Pediatr Surg 36:917-920.

Adolescent↗
PubMed2000

Changing patterns of lung cancer; (3/4 in.) 1.9 cm; still a safe length for bronchial resection margin?

BACKGROUND: Surgical resection is the best treatment modality in non-small cell lung cancer (NSCLC). As a guideline, it is suggested that at least a bronchial resection margin of 1.9 cm from the macroscopic tumor might provide a tumor-free margin in lung cancer. In some recent reports, there is great emphasis on the changing histopathological patterns of lung cancer, but no concern for the proximal extension of lung cancer. The aim of this study was to determine the validity of this guideline in the current time. METHODS: Surgically resected specimens of NSCLC cases (n = 70) were examined. The bronchial tree including tumor was dissected and beginning from the edge of the visible tumor, the bronchus were cut into serials in its transverse plane, 5 mm apart from each other. Cut sections were examined for proximal extension of tumor at different levels. RESULTS: Microscopic proximal extension was observed in 24.2% (n = 17/70) of all the cases. Peribronchial extension (n = 9/17) (52.9%) was more predominant compared with bronchial extension (n = 8/17) (47.0%). Squamous cell carcinoma (n = 11/38) (28.9%) showed proximal extension more than adenocarcinoma (n = 5/23) (21.7%). Adenocarcinoma showed more peribronchial extension (n = 4/5) (80.0%) whereas squamous cell carcinoma (n = 7/11) (63.6%) showed more bronchial extension. The farthest extension was 3.0 cm for adenocarcinoma and 2.0 cm for squamous cell carcinoma. Excluding tumor positive specimens beyond 1.5 cm level to the bronchial resection margin, all tumors accounted for 96% of the whole series. CONCLUSIONS: Microscopic proximal extension of lung cancer occurs in 24.2% of NSCLC cases. Squamous cell carcinoma extends more proximally compared with adenocarcinoma in ratio whereas adenocarcinoma extends more in length. A bronchial resection of 1.5 cm in length from the macroscopic tumor will provide clear margins in 93% of NSCLC cases.

Adult↗
PubMed2000

The antioxidative defense in asthma.

Asthma is a disease characterized by chronic airway inflammation. Generation of oxygen free radicals by activated inflammatory cells produces many of the pathophysiologic changes associated with asthma and may contribute to its pathogenesis. However, the activities of antioxidant enzymes and their relation with asthma have not been well defined. This study was performed to examine the activities of major intracellular antioxidants in mild asthmatic patients. Twelve asymptomatic mild asthmatic patients who never used any antiasthma medication and 13 age- and sex-matched healthy control subjects were selected. The activities of erythrocyte antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione-peroxidase (GSH-Px) were measured spectrophotometrically. The mean SOD activity of asthmatic patients was found to be significantly lower than that of the controls (p < 0.05). There was no significant difference in CAT and GSH-Px activities between patients and controls (p > 0.05). Although the mechanisms underlying the association between asthma and antioxidant system are unclear, according to our findings, decreased antioxidant protection may contribute to the pathogenesis of mild asthma.

Adult↗
PubMed1999

Fibrohistiocytic tumor of the trachea in a child.

A 10-year-old girl who had been treated for presumed asthma during the previous year, was admitted to our hospital with dyspnea and wheezing. An endotracheal tumor was detected and a tracheal resection was performed. The tumor was diagnosed as a fibrohistiocytic tumor. Biologic behavior of fibrohistiocytic tumors of the trachea is not clear and morphologically similar cases are interpreted as malignant or benign by different authors. However, an analysis of the present case and 11 well documented cases in the literature shows that this tumor must be evaluated as a low-grade malignancy and initial complete tumor resection is necessary.

Airway Obstruction↗
PubMed1999

Platelet aggregation in traumatic spinal cord injury.

STUDY DESIGN: Collagen-induced platelet aggregation and platelet count of ten paraplegic patients (four females, six males, aged 16 - 42 years) with traumatic spinal cord injury (SCI) (posttraumatic 12 - 48 weeks) and of ten age-matched healthy volunteers (control group; five females, five males, aged 18 - 37 years) were investigated. OBJECTIVES: Investigation of platelet aggregation in the whole blood of the patients with SCI. SETTING: Ankara/Turkey. METHODS: Platelet aggregation was evaluated by impedance technique using Chrono Log Model 560 WB aggregometer in whole blood. Platelet count was determined by Medonic Cell Analyser 610. RESULTS: Maximal intensity of collagen-induced platelet aggregation of the patients was 18.50+/-8.28 ohm (mean+/-SD) and of the controls was 7.60+/-4.25 ohm. Maximal rate of collagen-induced aggregation of platelets from the patients was 3.98+/-1.59 ohm/min, maximal rate of aggregation of platelets from the controls was 1.57+/-1.01 ohm/min. Platelet counts of the patients and controls were 290 500+/-50 357/mm3 and 273 000+/-48 343/mm3 respectively. It was determined that both maximal rate (P<0.001) and maximal intensity (P<0.01) of collagen-induced platelet aggregation of the patients were significantly higher than those of the controls. There was no significant difference between the two groups in respect to platelet counts. CONCLUSION: Collagen-induced platelet aggregation of patients with traumatic SCI 12 - 48 weeks after the trauma was significantly higher than that of the controls. Our results indicate that increased tendency of platelet aggregation, which is probably induced by free radicals, may have a great impact on the late thromboembolic complications reported in patients with traumatic SCI.

Adolescent↗
PubMed1998

The effect of pre-induction clonidine on platelet aggregation during minor surgery.

OBJECTIVE: This paper reports the results of a prospective randomized double-blind trial on the effects of pre-operative clonidine on platelet aggregation. METHODS: Thirty adult (ASA I-II) patients undergoing elective minor orthopaedic surgery were randomly allocated into three groups of ten patients each. In group I clonidine 2 microg x kg(-1), in group II clonidine 4 microg x kg(-1) and in group III saline placebo was administered intravenously before the induction of anaesthesia. Anaesthesia was induced with propofol and vecuronium and maintained with halothane-nitrous oxide. Platelet counts and aggregation tests were performed before (t0) and 1 h (t1) and 24 h (t24) after administration of the study drug. RESULTS: Changes in platelet counts among the groups and values over time were not significant. Both maximum rate and intensity of collagen-induced aggregation in both clonidine groups and maximum intensity of adenosine 5'-diphosphate (ADP)-induced aggregation in the high-dose clonidine group increased significantly at t1. However, all these increases in aggregation were within the normal ranges. CONCLUSION: The effects of both low and high doses of clonidine on platelet aggregation appeared to be minor, and we did not observe any increases above the normal ranges.

Adult↗
PubMed1998

Superoxide dismutase activity in healthy and inflamed pulp tissues of permanent teeth in children.

The free radicals play an important role in the tissue damage. Oxygen-derived free radicals are controlled by various cellular defense mechanisms consisting of enzymatic such as superoxide dismutase, catalase, glutathion peroxidase and nonenzymatic scavenger components. Superoxide dismutase (SOD) is responsible for the dismutation of the superoxide radicals into hydrogen peroxide and molecular oxygen. In this study, pulp samples extirpated from the teeth of the 27 children between 10-15 ages which diagnosed to be healthy, reversible pulpitis or symptomatic irreversible pulpitis were evaluated for the activity of superoxide dismutase enzyme. There were statistically significant differences between healthy and reversible pulpitis, and between reversible and symptomatic irreversible pulpitis groups. The SOD activity of the reversible pulpitis group were significantly lower than the irreversible pulpitis and healthy pulp groups. The evaluation of the data revealed that the quantity of SOD as a vitality protector enzyme is low at the beginning of the inflammation as a consequence of rapidly depletion and/or destruction of this enzyme, but as the inflammation proceeds the pulp tissue showed adaptation to this situation.

Adolescent↗
PubMed1998

Platelet aggregation and release function in hyperbaric oxygenation.

The aim of the study was to investigate the acute and chronic effects of hyperoxygenation on platelet aggregation and adenosine triphosphate (ATP) release. To observe the acute effects of hyperbaric oxygen (HBO2), seven New Zealand rabbits were exposed to 2.4 atm abs oxygen for 90 min (group 1). Eight other rabbits were further exposed to O2 daily for 20 days (group 2) to observe the chronic effects of HBO2. Adenosine diphophate (ADP) and collagen-induced platelet aggregation and ATP release were evaluated before and after oxygenation in groups 1 and 2. It was found that the maximal rate of ADP and collagen-induced platelet aggregation decreased after hyperbaric oxygenation in group 1. No significant alteration was observed in platelet responses at the end of 20 days of oxygenation in group 2. The adaptation of platelets of 2.4 atm abs O2 after 20 days of exposure seems to need further investigation.

Adenosine Diphosphate↗
PubMed1997

Pseudoneglect of males and females on a spatial short-term memory task.

The effect of sex on the phenomenon of pseudoneglect was assessed in 60 male and 61 female right-handed subjects using a modified form of Corsi's block-tapping test. A significant right-lateralized pseudoneglect for both sexes was found, and the level of pseudoneglect strongly correlated with neglect in the right hemispace. Men were significantly more accurate in the left hemispace than women, whereas no difference was seen between the sexes in the right hemispace. Although we found some indirect evidence from which to infer that the men's brain may be functionally more lateralized than the women's for this spatial task, there was no significant difference between the sexes in correct responses for the left hemispace, i.e., right pseudoneglect. Therefore, the results suggest that pseudoneglect phenomenon can be partly explained by a functional asymmetric feature of the brain, and the other factors probably play a role in producing the similar patterns of asymmetric perception of space in males and females.

Adult↗