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Biomedical subjects

Y Büyükaşik

Publications and source records attributed to Y Büyükaşik.

At least 19 recordsLinked to original sources
PubMed2005

The plasma levels of prostanoids and plasminogen activator inhibitor-1 in primary and secondary thrombocytosis.

An elevated platelet count is a common finding in both hospitalized and ambulatory patients. Thrombosis and bleeding complications are more frequently observed in patients with clonal thrombocytosis than secondary thrombocytosis. The aim of this study was to investigate the behaviors of plasminogen activator inhibitor type 1 (PAI-1), the inhibitor of fibrinolysis; and thromboxane A2 and 6-keto-PGF1 alpha, the products of endoperoxides, in 16 patients affected with clonal thrombocytemia as compared with 16 patients with reactive thrombocytosis and 15 normal controls. In the clonal thrombocytemia group, plasma levels of PAI-1 antigen and activity were significantly higher than both reactive thrombocytosis and control group. Plasma levels of 6-keto-PGF1alpha were significantly higher in the clonal thrombocytemia group than the other two groups and also higher in the reactive thrombocytosis group than the control group, which was also significant. This study confirms that arachidonate metabolism is frequently deranged in patients with thrombocytosis and hypofibrinolysis due to increased PAI-1 plasma levels as shown in the clonal thrombocytosis group. This may explain the thrombotic tendency in myeloproliferative disorders.

Adolescent↗
PubMed2004

Plasma basic fibroblast growth factor and bone marrow fibrosis in clonal myeloproliferative disorders.

Basic fibroblast growth factor (bFGF) is an important growth factor involved in clonal hematopoietic expansion, neoangiogenesis, and bone marrow fibrosis, all of which are important pathobiologic features of clonal chronic myeloproliferative disorders (CMPD) and myelodysplastic syndromes (MDS). The aim of this study was to assess circulating bFGF concentrations in patients with CMPD and MDS with respect to the presence of bone marrow fibrosis in histopathologic examination. The study group comprised 18 patients with CMPD (six female, 12 male; median age 50 years), seven patients with MDS (one female, six male; median age 66 years) and 10 healthy adults as controls (four female, six male; median age 29 years). CMPD group included six chronic myelogenous leukemia (CML), seven essential thrombocythemia (ET), three polycythemia vera (PV), two agnogenic myeloid metaplasia (AMM). All seven MDS patients were the FAB subtype of refractory anemia (RA). Bone marrow biopsy sections stained with hematoxylin and eosin (H & E) and for reticulin were examined for the presence of fibrosis. The median plasma bFGF level was 18.2 pg/ml (interquartile range, IQR: 15.2-26.7) in patients with CMPD, 18.0 pg/ml (IQR: 15.8-26.4) in patients with MDS, 13.6 pg/ml (IQR: 9.9-20.0) in the control group. The bFGF levels were significantly higher in patients with CMPD in comparison with the healthy control group (P = 0.031). Circulating bFGF tended to be significantly lower in relation to the development of marrow fibrosis (P = 0.028). The complicated interactions of bFGF and fibrosis in the context of CMPD may be either 'cause' or 'effect'. The bFGF might represent an important link between angiogenesis, fibrosis, and clonal neoplastic hematopoiesis during the development of CMPD.

Adult↗
PubMed2004

The predictability of factor V Leiden (FV:Q(506)) gene mutation via clotting-based diagnosis of activated protein C resistance.

After the discovery of activated protein C resistance (APCR) due to factor V Leiden mutation and the causal relationship of the phenomenon with clinical thromboembolism, a wide variety of functional clotting-based assays were developed for testing of APCR in relation to the specific DNA-based analysis of FV:Q(506) Leiden. The aim of this study is to assess a clotting-based APCR assay using procoagulant crotalidae snake venom with respect to the sensitivity, specificity, and predictability for the presence of the factor V Leiden mutation. APCR testing and factor V DNA analyses have been performed concurrently on 319 patient specimens. APCR values of the patients with homozygous factor V Leiden mutation (70.4+/-13.5 s) were significantly lower (p<0.001) in comparison to the subjects with the heterozygous mutation (87.6+/-13.4 s). The assay is highly sensitive (98.7%) and specific (91.9%) for the screening of factor V Leiden mutation. The sensitivity and specificity of the APCR testing reached to 100% below the cut-off value of 120 s among the patients with homozygous factor V Leiden mutation. Therefore, this method could help the desired effective optimal screening strategy for the laboratory search of hereditary thrombophilia focusing on the diagnosis of APCR due to FV:Q(506).

Activated Protein C Resistance↗
PubMed2001

Pregnancy complicated by Evan's syndrome.

Evan's syndrome was initially diagnosed in a 26-year-old pregnant patient. Following the introduction of high dose steroid therapy, the patient developed possible disseminated gonococcal infection which was followed by preterm labor and abruptio placentae. A cesarean delivery was performed at the 34th week of pregnancy following platelet infusion. While the infant survived, the mother had delayed postpartum hemorrhage.

Abruptio Placentae↗
PubMed2001

Cardiac and great vessel thrombosis in Behçet's disease.

Behçet's disease (BD) is a chronic relapsing systemic vasculitis in which orogenital ulceration is a prominent feature. The disease affects many systems and causes hypercoagulability. We present a 27-year-old male patient who exhibited widespread great vessel thrombosis including right atrial and ventricular thrombi in the setting of right-sided infectious endocarditis and orogenital aphthous ulcerations and erythema nodosum due to BD. We reviewed the enigmatic prothrombotic state of BD, and discuss our prior experiences in this field.

Adult↗
PubMed2000

A unifying hypothesis for the renin-angiotensin system and hematopoiesis: sticking the pieces together with the JAK-STAT pathway.

JAK-STAT pathway is a recently encountered intracellular signal transduction system. The pathway is utilized by numerous cytokines, growth factors, and hormones for gene expression and a variety of biological activities. Hematopoiesis is regulated by many cytokines and growth factors that support the proliferation and differentiation of progenitor cells in the bone marrow. JAK-STAT pathway arises as the most common signalling cascade of a wide range of cytokines and/or growth factors in propagation of physiological and pathological/neoplastic hematopoiesis. On the other side, renin-angiotensin system (RAS) includes not only the classic circulating endocrine system controlling blood pressure and electrolyte homeostasis, but also tissue-specific RASs with autocrine and/or paracrine functions. Preliminary data suggest the involvement of the RAS components in normal and pathologic hematopoiesis, although the precise mechanism of action has not been elucidated yet. We have hypothesized, in this report, that JAK-STAT pathway serves as a point of crosstalk between the components of the locally present RAS in the bone marrow and hematopoiesis. Demonstration of a local RAS in the bone marrow with clarification of the postreceptor signalling events may play a consequential role not only for further clarification of normal hematopoiesis but also novel therapeutic approaches in pathologic/neoplastic conditions.

Hematopoiesis↗
PubMed2000

Selectin adhesion molecules in Behçet's disease.

OBJECTIVES: The pathogenesis of Behçet's disease (BD) is closely related to endothelial cells, leucocyte functions and autoimmunity. The aim of this study was to investigate circulating selectin adhesion molecules, which are known to play a significant part in the immune response especially by regulating interactions of the leucocytes with endothelium, in BD. METHODS: Plasma E-, L-, and P-selectin concentrations were evaluated in 11 patients with widespread BD (group I), 10 cases with merely mucocutaneous involvement (group II) and 15 age and sex matched healthy control subjects. The patients were newly or previously diagnosed cases not taking any drug for BD. RESULTS: Plasma concentrations of all selectins were significantly higher in group I compared with group II. E-selectin and P-selectin were significantly increased in each subgroup of patients compared with the healthy controls. L-selectin concentrations were higher than the controls only in group I. CONCLUSIONS: Increases in the selectins in BD may be a direct consequence of the leucocyte, endothelium and platelet activations observed during the disease process. However, abnormal/increased selectin expression to various triggers should also be considered. More prominent increases in patients with extensive disease suggest that circulating selectin concentrations are related to disease severity.

Adult↗
PubMed1999

Influence of thrombolytic therapy on the incidence of left ventricular thrombi after acute anterior myocardial infarction: role of successful reperfusion.

BACKGROUND: Previous studies have reported controversial results regarding the effectiveness of systemic thrombolysis in preventing left ventricular (LV) thrombus after acute myocardial infarction (MI). HYPOTHESIS: This study was performed to evaluate the influences of thrombolysis, and particularly successful reperfusion, on the incidence of LV thrombus formation after acute anterior MI. METHODS: In all, 191 patients suffering from a first attack of acute anterior MI were prospectively evaluated by two-dimensional echocardiography and coronary angiography, performed at the end of the first week and within the first two weeks of MI, respectively. Of these, 98 who presented within 12 h of onset of symptoms received intravenous streptokinase (1.5 million IU), while the remaining 93 patients who, either because of contraindications or late admission, did not receive thrombolytic treatment served as control group. All patients received aspirin and full-dose anticoagulation with intravenous heparin. Successful reperfusion in the streptokinase group was assessed by enzymatic and electrocardiographic evidence. RESULTS: The overall incidence of LV thrombi was 24.6% (47/191). When all patients were evaluated, no statistically significant difference was found between the frequency of LV thrombi in the patients who had thrombolysis (22.4%) and those who did not (26.8%), despite a trend toward the formation of fewer thrombi in the initial group (p > 0.05). However, the patients who had successful reperfusion with streptokinase (n = 64) had significantly reduced incidence of LV thrombi compared with those who did not receive thrombolytic therapy (20 vs. 26.8%, p < 0.05). Stepwise multivariate analysis suggested that LV abnormal wall motion score (p = 0.01) and presence of LV aneurysm were independent predictors of LV thrombus formation in patients with acute anterior MI. CONCLUSION: Not all patients who received streptokinase for acute anterior MI, but only those with successful reperfusion had reduced incidence of LV thrombi. The favorable effects of thrombolysis on LV thrombus formation are probably due to the preservation of global LV systolic function.

Aged↗
PubMed1999

Increased systemic coagulation activity in patients with rheumatic mitral stenosis: assessment of the clinical and echocardiographic determinants.

In this study, we aimed to determine systemic coagulation activity in patients with rheumatic mitral stenosis and to define determinants of a possible prethrombotic state. Peripheral venous plasma level of thrombin-antithrombin III complex was measured in 84 consecutive patients with rheumatic mitral stenosis who had no left atrial thrombus by transesophageal echocardiography. The patients had significantly higher thrombin-antithrombin III complex values (mean +/- SD = 9.6+/-15.9 ng/ ml) compared with the healthy subjects (2.1+/-1.8 ng/ml) (P<0.001). Among many clinical and echocardiographic variables, severe mitral regurgitation (odds ratio = 6.7, P<0.001) and left atrial spontaneous echo contrast (odds ratio = 22.8, P<0.001) appeared as significant predictors of the increased systemic coagulation activity in multivariate logistic regression analysis. In conclusion, systemic coagulation activity is increased in the patients with rheumatic mitral stenosis, and coexistence of severe mitral regurgitation and presence of left atrial spontaneous echo contrast are determinants of this increment.

Adult↗
PubMed1999

Selectins and IL-6 during the clinical course of idiopathic thrombocytopenic purpura.

'Stress thrombocytes', i.e. large and presumably hyperfunctioning platelets, is a well-known characteristic of patients with idiopathic thrombocytopenic purpura (ITP). Therefore, despite what may be severe thrombocytopenia these patients generally do not suffer from severe life-threatening hemorrhage. The plasma level of soluble P-selectin (sP-selectin) is a valuable marker reflecting platelet activation. Available data suggest that interleukin-6 (IL-6) may contribute to the regulation of megakaryocytopoiesis and platelet activity. The purpose of this study is to investigate the status and kinetics of IL-6 and selectins, which are involved in the platelet function, production, and immunologic functions, during the clinical course of ITP, that may be helpful for understanding the biology of the disease. Twenty-two ITP patients were studied prospectively in the course of their disease. Sixteen, 8 and 6 patients were available after platelet recovery, relapse and splenectomy, respectively. Fifteen healthy persons served as a control group. Higher levels of both sP-selectin and IL-6 were observed in all clinical stages of disease compared to the control group. However, more prominent elevations were present during active stages of ITP, i.e. pretreatment (p < 0.001 vs. control group for both sP-selectin and IL-6) and relapse periods (p < 0.001 vs. control group for both sP-selectin and IL-6). Pretreatment soluble L-selectin and soluble E-selectin levels were not different from the controls. Both sP-selectin (r = -0.32, p = 0.019) and IL-6 (r = -0. 41, p = 0.002) levels inversely correlated with platelet count during disease course. There was a positive correlation between the sL-selectin level and leukocyte count (r = 0.60, p < 0.001). These results suggest that residual platelets are activated in ITP, which offers a relatively benign clinical course compared to other thrombocytopenias. High IL-6 concentration during thrombocytopenia may be involved in compensatory megakaryocytopoiesis and augmented 'residual platelet' functions in ITP.

Adult↗
PubMed1999

Circulating thrombomodulin, thrombospondin, and fibronectin in acute myeloblastic leukemias.

In this study, soluble thrombomodulin (TM) was measured as an indicator of endothelial injury in acute myelocytic leukemia (AML) together with fibronectin (FN) and thrombospondin (TS). The study group comprised of 17 (6 men, 11 women; aged 34 +/- 10 years; range 21-61 years) newly diagnosed AML patients. There was infection in 6 patients. Twelve (4 men, 8 women; aged 31 +/- 11 years; range 18-55 years) healthy subjects were studied as the control group. Plasma soluble TM levels were significantly higher in AML patients than in the healthy control group (116.6 +/- 13.7 vs 37.2 +/- 1.75 ng/ml, respectively (mean +/- SEM), p < 0.01). Plasma FN levels were found to be significantly higher in AML patients compared to the control group (15.9 +/- 2.69 vs 8.1 +/- 2.46 ng/ml, respectively (mean +/- SEM). p < 0.01 ). Plasma FN levels in infected patients were significantly lower than in non-infected patients (6.47 +/- 1.3 vs 21.0 +/- 3.1 ng/ml, respectively (mean +/- SD), p < 0.01). Plasma TS levels in the patient group were significantly lower than in the control group (20.6 +/- 1.45 vs 120.8 +/- 18.2 ng/ml, respectively (mean +/- SEM), p < 0.01). In one patient with M7 megakaryoblastic leukemia who also had a high platelet count, plasma TS levels were significantly higher than that in other patients.

Adult↗
PubMed1998

Activation of blood coagulation in patients with mitral stenosis and sinus rhythm.

The aim of this study was to assess whether there is blood coagulation activation in patients with mitral stenosis (MS) and sinus rhythm (SR) and to investigate the value of left atrial spontaneous echo contrast (LASEC) as a predictive sign of increased coagulation activity. Using thrombin-antithrombin III complexes and prothrombin fragment 1+2 as in vivo hemostatic markers, we concluded that there is a hypercoagulable state in patients with MS and SR when LASEC is present.

Adult↗
PubMed1998

Perianal infections in patients with leukemia: importance of the course of neutrophil count.

PURPOSE: This study was performed to evaluate relations among neutrophil count (including its course), type of lesion, treatment, and prognosis in patients with leukemia and perianal infection. METHODS: Medical records of patients with acute and chronic leukemia who were followed during the last five years were reviewed retrospectively. RESULTS: The incidence of perianal infections was found to be 7.3 percent in 259 patients with acute leukemia. Only 1 of 108 patients with chronic leukemia suffered from this problem. Twenty percent of all patients with this complication died as a result of sepsis. Perianal abscess was the sole and obligatory indication for surgical treatment in our patients. There were ten patients in each treatment group. The operative group had better results (9 cures, 1 complication vs. 3 cures, 7 complications). However, median neutrophil count at diagnosis was notably higher in the operative group 1,280/mm3 vs. 96/mm3; P = 0.075). Also, significantly more frequent abscess formations and, consequently, operative treatments were performed in patients with a period of normal neutrophil counts during the infection compared with continuously neutropenic patients (9 operative, 4 nonoperative vs. 1 operative, 6 nonoperative; P = 0.057). Ten cures, three complications vs. two cures, five complications (3 mortalities) were present in patients with and without normal neutrophil counts, respectively (P = 0.062). When only severely neutropenic patients were considered, four patients in the surgery group had normal neutrophil counts before or shortly after surgery. However, only two of eight patients with perianal cellulitis had normal counts during full-course infection (P = 0.06). CONCLUSIONS: The course of the neutrophil count during infection was an important factor affecting the perianal lesion, and indirectly, choice of treatment and prognosis. A period of normal counts during infection usually led to well bordered and fluctuant lesions, and the prognosis was acceptable with operative treatment. However, continuously neutropenic patients developed nonfluctuating indurations. We found disappointing results with nonoperative treatment of such patients. In all studies, regarding treatment of perianal infections in neutropenic patients, the course of the neutrophil count and indications for surgery should be clarified to get reliable results.

Adolescent↗
PubMed1998

Thrombopoietin, interleukin-6, and P-selectin at diagnosis and during post-steroid recovery period of patients with autoimmune thrombocytopenic purpura.

Plasma concentrations of the most potent megakaryocytopoietic cytokines, thrombopoietin (TPO) and interleukin-6 (IL-6), and the platelet activation marker P-selectin were evaluated in 24 patients with autoimmune thrombocytopenic purpura (ATP) who responded to conventional steroid treatment, at diagnosis and after steroid-induced recovery. Baseline TPO concentration (median [interquartile range]=0 [17.52] pg/ml) was significantly decreased and IL-6 (38 [19.75] pg/ml) and P-selectin (485 [393.75] ng/ml) were significantly elevated compared with healthy subjects (100 [68] pg/ml, 8 [7] pg/ml and 166 [69] ng/ml, respectively). Following steroid treatment, all values approached normal, i.e., TPO (20 [18.75] pg/ml) was increased and IL-6 (19.5 [13] pg/ml) and P-selectin (248 [172.5] ng/ml) were decreased, significantly. The decrease of TPO in ATP is suggested to occur due to increased megakaryocyte mass and, consequently, TPO clearance. The non-lineage-specific cytokine IL-6 may be elevated to compensate for megakaryocytopoiesis/thrombopoiesis. The elevation of P-selectin may reflect compensatory platelet hyperactivation; however, this molecule also might be a marker of platelet destruction.

Adult↗