[Show abstract][Hide abstract] ABSTRACT: Patients with haemophilia A have seriously impaired thrombin generation due to an inherited deficiency of factor (F)VIII, making them form unstable fibrin clots that are unable to maintain haemostasis. Data on fibrin structure in haemophilia patients remain limited. Fibrin permeability, assessed by a flow measurement technique, was investigated in plasma from 20 patients with severe haemophilia A treated on demand, before and 30 minutes after FVIII injection. The results were correlated with concentrations of fibrinogen, FVIII and thrombin-activatable fibrinolysis inhibitor (TAFI), and global haemostatic markers: endogenous thrombin potential (ETP) and overall haemostatic potential (OHP). Fibrin structure was visualized using scanning electron microscopy (SEM). The permeability coefficient Ks decreased significantly after FVIII treatment. Ks correlated significantly with FVIII levels and dosage, and with ETP, OHP and levels of TAFI. SEM images revealed irregular, porous fibrin clots composed of thick and short fibers before FVIII treatment. The clots had recovered after FVIII replacement almost to levels in control samples, revealing compact fibrin with smaller intrinsic pores. To the best of our knowledge, this is the first description of fibrin porosity and structure before and after FVIII treatment of selected haemophilia patients. It seems that thrombin generation is the main determinant of fibrin structure in haemophilic plasma.
Thrombosis and Haemostasis 11/2013; 111(4). · 5.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The study included 48 untreated patients with monoclonal gammopathies (MG). Paraprotein was isolated from the serum of 10 patients with decreased platelet aggregation. Platelet aggregation was measured before and after the addition of the isolated paraprotein to platelet-rich plasma (PRP) from 10 healthy donors, in vitro. Expression of platelet von Willebrand factor (vWF) receptor glycoprotein (GP)Ib and platelet collagen receptor GPVI was determined by flow cytometry in the PRP of healthy donors before and after the addition of isolated paraprotein using the monoclonal antibodies, CD42b (for GPIb) and CD36 (for GPVI). Flowcytometry showed that expression of CD42b and CD36 positive cells was reduced after the addition of isolated paraprotein to PRP from healthy donors (p < 0.001). These investigations demonstrated that paraprotein causes platelet dysfunction in patients with MG due to specific binding to the platelet vWF receptor GPIb and platelet collagen receptor GPVI.
[Show abstract][Hide abstract] ABSTRACT: With an increase in the use of imidazolinone (IMI)-resistant sunflower, it is important to determine the influence of weed interference and herbicide presence on seed yield and yield components of sunflower. The objective of this study was to determine the effect of different periods of weed presence on seed yield and yield components of IMI-resistant sunflower grown with and without pre-emergence (PRE) herbicide. Field studies were conducted in 2008 and 2009 at three locations in Serbia and one location in Nebraska, USA. A four-parameter log-logistic model described relationship between the crop yield and yield components to increasing duration of weed presence. Sunflower yield and yield components varied between years and among locations. Increasing periods of weed interference decreased yield and yield components of sunflower; however, the reductions were greater without PRE herbicide compared to the PRE herbicide treated plots. The length of time weeds could remain in the crop grown without PRE herbicide ranged from 14 to 26 days after emergence (DAE), which corresponded to the V3 (three leaves) to V4 growth stages on the basis of the 5% acceptable yield loss level. The duration of time that weeds could remain in the crop grown with PRE herbicide ranged from 25 to 37 DAE, which corresponded to the V6–V8 growth stages of sunflower. Practical implication of this study is that post-emergence weed control in IMI-resistant sunflower grown with PRE herbicide can be delayed approximately by two weeks compared to the crop grown without PRE herbicide.
Field Crops Research 03/2012; 128:137–146. · 2.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Repeated thromboses are the most frequent clinical manifestation of antiphospholipid syndrome (APS) in the presence of antiphospholipid antibodies (aPL). The objective of this study was to observe the prevalence and localization of thrombosis, and to investigate the importance of aPL type and level for thrombosis-related events in patients diagnosed with APS. These are the first results of patients enrolled in Serbian National Cohort Study which comprises 256 patients: 162 with primary antiphospholipid syndrome (PAPS) and 94 with APS associated with systemic lupus erythematosus (SLE). aPL analysis included detection of aCL (IgG/IgM), β(2)GPI, and lupus anticoagulant. Thrombosis was diagnosed in 119 (46.5%) patients, with higher prevalence in PAPS compared with SLE patients (51.2% and 38.3%, respectively, p = 0.045). There was similar prevalence of arterial thrombosis in PAPS and SLE groups (34.6% and 34%, respectively, p = 0.932) although venous thrombosis was more frequent in PAPS (25.9% and 8.5%, respectively, p = 0.001). Thrombosis was observed in 92 (55.8%) patients who had more than one type of antibody (category I), in 13 (41.9%) patients with category IIa, in 19 (46.3%) patients with category IIb, and in 73 (44.2%) patients with category IIc (p = 0.10). The patients with thrombosis were older than those without thrombosis (49.8 and 39.8 years, respectively, p = 0.001). Overall, older age was a risk factor for thrombosis. The prevalence of venous thrombosis was higher in the PAPS group, but with lower frequency than in literature data. Any aPL type and level is a risk factor for thrombosis.
[Show abstract][Hide abstract] ABSTRACT: Thrombin activatable fibrinolysis inhibitor (TAFI) down-regulates fibrinolysis after activation by thrombin/thrombomodulin. We investigated the effect of treatment with FVIII concentrate on plasma levels of pro-TAFI and activated TAFI in haemophilia A patients.
Samples were collected pre and posttreatment from patients treated prophylactically or on-demand. Pro-TAFI, TAFI/TAFIi and FVIII levels were measured in all samples.
Treatment had no effect on pro-TAFI levels. Pro-TAFI was similar in both patient groups but higher than in controls. Patients from the prophylactic treatment group had measurable FVIII levels pretreatment while in the treatment-on-demand group FVIII levels were ≤0.01 IU/mL. In the prophylactic treatment group, the levels of TAFI/TAFIi were significantly lower pre- and posttreatment (4.31 ± 3.14 and 3.48 ± 2.65 ng/mL respectively) than in the on-demand group (13.02 ± 3.47 and 14.87 ± 3.47 ng/mL respectively). This difference may be due to release of tissue factor at the injury site in the on-demand group. This could induce thrombin and TAFI activation within the clot counterbalancing fibrinolysis in these patients. In the prophylactic group, no injury existed, thus there was insufficient thrombin generation within the clot to activate TAFI.
These findings suggest that in patients to whom FVIII is administered on demand the fibrinolysis activity is more down regulated than in patients following a prophylactic treatment regime.
International journal of laboratory hematology 06/2011; 34(1):35-40. · 1.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Glyphosate resistance was found in Lolium rigidum Gaudin (Rigid ryegrass, LOLRI) in South Africa. Suspected glyphosate-resistant L. rigidum populations were collected and grown under greenhouse conditions. The plants were sprayed with a range of doses of gl-yphosate 35 days after planting and shoot dry biomass was determined 17 days after her-bicide treatment. Based on the dose-response experiment conducted in the greenhouse, one population of L. rigidum suspected to be resistant to glyphosate was approximately 5.3 fold more resistant than susceptible population. The other population was 2.8 fold more resistant than susceptible population. Difference between the two suspected resistant po-pulations was 1.9 fold. All plants were treated with glyphosate (1000 g a.i. ha -1) and shikimic acid was extracted 2, 4 and 6 days after treatment. The plants of susceptible populations accumulated more shikimic acid than other two populations.
[Show abstract][Hide abstract] ABSTRACT: Limited data exist in the literature regarding the effects of homocysteine thiolactone on the activity of the acetylcholinesterase (AChE) in the blood, and practically no data exist regarding the influence of homocysteine thiolactone on the enzyme in the brain and heart. Taking into consideration the importance of hyperhomocysteinemia in clinical practice, it has been thought to be of particular interest to examine the
effect of homocysteine thiolactone on the activity of AChE in the rat's blood, brain and heart. In this study, male Wistar rats (weighing 250-300g) were used, and they were divided into two groups; one served as a control group and receieved a placebo (1 ml 0.9 % NaCl, i.p.), while the other group received a homocysteine thiolactone solution (5.5 mmol/kg b.m., i.p.). An hour after the administration, the rats were euthanized by
decapitation, heir tissues were harvested, buff ered, and homogenized in a phosphate buff er (pH 8). The concentration in the tissue homogenates was 20 mg of tissue per 1 ml of buff er. The buffered and homogenized parts of the tissues were used as substrates for spectrophotometric measurements. The AChE activity was then measured by the Ellman method. Statistical analysis was conducted using a one-way ANOVA test, and the intergroup comparisons were performed using a Bonfferoni test. The results showed a significant reduction in AChE activity in all tissues obtained from the animals treated with homocysteine thiolactone compared to the enzyme activity of the control group. In addition, the results also showed that the blood enzyme activity inhibition was the lowest (12%), while the enzyme activity was slightly higher in the brain (27.8%) and heart specimens (86.3%). It was concluded that homocysteine thiolactone significantly inhibited AChE activity in the heart and brain tissue, but not in the blood of the rat.
Serbian Journal of Experimental and Clinical Research 01/2010; 11(1):19-22.
[Show abstract][Hide abstract] ABSTRACT: We describe two patients with diagnosis of chronic lymphocytic leukemia (CLL) in whom interphase fluorescence in situ hybridization (FISH) analysis revealed trisomy 12 and del(13)(q14.3) occurring in the same clone. These abnormalities are rarely seen together and the prognostic relevance of their coexistence is still unclear. According to some data, a probable adverse prognosis for this group of patients is suggested. Our patients have been in a stable phase of the disease for more than one year since the given abnormalities were documented in their karyotypes. Further study is necessary to determine the prognostic significance of coexistence of these abnormalities in CLL patients.
Archives of Biological Sciences 01/2009; · 0.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The conflicting data are reported on the clinical significance of VEGF deregulation and intensity of angiogenesis in multiple myeloma. The aim of this study was to evaluate the incidence and prognostic significance of VEGF expression and microvessel density (MVD) in multiple myeloma, as well as the relationship of their expression with selected clinical data, histological features, and proliferative activity of myeloma cells. We analyzed bone marrow biopsy specimens obtained from 59 patients with newly diagnosed multiple myeloma. Expression of VEGF and MVD was analyzed using standard immunohistochemical method (antibodies against VEGF and CD34, respectively) on B5-fixed and routinely processed paraffin-embedded bone marrow specimens. MVD was estimated by counting the number of microvessels in three "hot spots" at 400x magnification. VEGF immunoreactivity was estimated on the basis of intensity and percentage of positive plasma cells. VEGF was expressed in 47/59 (79.7%) specimens. There was no significant correlation between VEGF overexpression and age, clinical stage, the extent of osteolytic lesions, type of monoclonal protein, hemoglobin concentration, platelet count, serum concentration of creatinine, calcium, and albumins, the extent of bone marrow infiltration, histological grade, and proliferative activity index (measured with Ki-67 immunoreactivity). No significant difference was observed regarding the overall survival between VEGF-positive and VEGF-negative patients (29 vs. 34 months, P = 0.8). Median MVD was 15, ranging from 1 to 89 microvessels per three "hot spots". There was significant correlation between MVD and histological grade, the extent of bone marrow infiltration, and proliferative activity. Significant difference was observed regarding the overall survival between patients with low MVD (<15) and patients with high MVD (> or = 15) (46 vs. 22 months, P = 0.009; univariate analysis). The results of this study did not reveal clinical significance of VEGF overexpression in multiple myeloma. On the contrary, the extent of bone marrow angiogenesis is an indicator of biological potency of malignant clone and a predictor of poor survival in newly diagnosed myeloma.
Medical Oncology 05/2008; 25(4):451-7. · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Paragangliomas are tumors arising from the extra-adrenal paragangliar neural crest cells. The sympathoadrenal neuroendocrine system consists of extra-adrenal paragangliar cellular layer along the paravertebral and para-aortic axis, and the adrenal medullae. Paraganglioma should be included in the differential diagnosis of secondary erythrocytosis due to its possible ectopic erythropoietin (EPO) secretion. Thus, in this report we present a 24-year-old female patient with onset of unregulated ectopic EPO secretion, and consecutive erythrocytosis followed by hypertension, secondary to paraganglioma of multifocal retroperitoneal localization. Clinical, laboratory, and radiological investigations confirmed both an elevated EPO level and the presence of multiple paraganglioma. This paraneoplastic-mediated medical condition with high risk of cellular hyperviscosity syndrome (CHVS) requires prompt diagnosis and rapid therapeutic interventions. Initially, simple phlebotomy procedures were used; following that, tumors were surgically removed. In the course of the disease, this tumor relapsed, and urgent apheresis, as a treatment of life-threatening state, was used. The therapy performed resulted in a rapid blood viscosity depletion and a significant (P < 0.01) serum EPO reduction, as well as the general clinical benefit. Therefore, we conclude that the use of our own "multi-manner" apheresis (erythrocythapheresis plus plasma exchange), for long-time interval (until further causative therapy), effectively cross-bridged the possible hazards of EPO-dependent CHVS.
Medical Oncology 01/2008; 25(2):148-53. · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to evaluate immunophenotypic profile along with clinical follow-up in patients with advanced stage mantle cell lymphoma (MCL), and their possible influence on overall survival (OS). Bone marrow (BM) cell and/or peripheral blood mononuclear cell flow cytometric analyses of the following antigens were performed: HLA-DR, CD19, CD20, CD22, CD23, CD25, CD10, SmIg, kappa, lambda, CD79b, CD38, FMC7, CD3, CD2, and CD5. There were 14 patients in IV CS, and 26 patients in CS V. All patients were treated with CHOP. Immunological markers showed a typical phenotype (CD5+ CD23-, Cyclin D1) in all cases. Pathohistological type of BM infiltration was predominantly diffuse (72.5%), and in remainder of patients, nodular. Comparison of patients with leukemic phase of MCL with CSIV (BM), has shown significantly higher expression of CD19, CD20, and CD23, followed by permanently negative expression of CD23. Patients with blastic variant of MCL had higher expression of CD23, compared to typical MCL (P < 0.001). Median OS was 20 months, and there were no significant OS-differences between CS IV and leukemic phase patients. Survival analyses showed that negative prognostic influence had high IPI (P < 0.01), presence of extranodal localization (P < 0.01), and diffuse type of BM involvement (P < 0.01). Using Cox regression according to OS, IPI had independent prognostic value (P < 0.001). Our results demonstrated that in the advanced MCL patients the most powerful prognostic factor was IPI, while extranodal localization and type of BM infiltration were of a limited value.
Medical Oncology 09/2007; 24(4):413-8. · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The coexistence of systemic lupus Erythematosus (SLE) and multiple myeloma (MM) is uncommon and the pathogenetic mechanisms underlying this association remain unclear. We report the case of a woman who was diagnosed with SLE in 1993 aged 57, then developing IgA lambda type MM in the IIB clinical stage 7 years later. The SLE was treated successfully with methylprednisolone and chloroquine, and low dose maintenance steroid was continued with bisphosphonate protection until December 1994 when she suffered multiple vertebral fractures. She continued to receive 4 mg alternate day methylprednisolone and calcitonin until she decided to discontinue her own treatment 2 years later. In 2000, while still in stable SLE remission, she was diagnosed with MM. Protein electrophoresis revealed the IgA lambda paraprotein (40.5 g/l) and she had a Bence Jones (BJ) proteinuria of the lambda light chain type. Bone marrow trephine biopsy revealed a massive patchy infiltrate of abnormal plasmocytes (70%), while an extensive x-ray skeletal survey did not show any new fractures or osteolysis. The patient was treated according to the VMCP protocol without attaining a plateau phase. There was a similar poor clinical response to second and third line treatments (VAD, Thalidomide, Melphalan, and high dose dexamethasone). After 4 years of refractory disease the patient died from severe bilateral pneumonia. This case is discussed with reference to the literature.
Medical Oncology 02/2007; 24(4):445-8. · 2.06 Impact Factor