Biomedical subjects

M Blazek

Publications and source records attributed to M Blazek.

At least 19 recordsLinked to original sources

PubMed2007

Plasma tissue factor in coronary artery disease: further step to the understanding of the basic mechanisms of coronary artery thrombosis.

Tissue factor is a cell surface protein that is expressed constitutively by monocytes, macrophages and fibroblasts, but also by some other cells in response to a variety of stimuli. The main function of the tissue factor is to form a complex with factor VII/VIIa that converts factors IX and X to their active forms. Tissue factor is also involved in the pathophysiology of systemic inflammatory disorders, coagulopathies, atherosclerotic disease, tumor angiogenesis and metastasis. Increased tissue factor expression either locally in the coronary plaques or systematically on circulating blood elements of patients with acute coronary syndromes may be responsible for increased thrombin generation, thus leading to platelet activation and fibrin formation. Tissue factor therefore plays a pivotal role in the initiation of thrombotic complications in patients with coronary artery disease.

Biomarkers↗

PubMed2005

[Acetylsalicylic acid (ASA) resistance in patients with ischemic heart disease (IHD) as bioindicator of the treatment strategy].

BACKGROUND: The interest in aspirin resistance has been increasing during the last few years, with researchers earnestly pursuing alternative anti-platelet therapies and devices for measuring platelet aggregation. The recent studies suggest that 5-45% of patients taking aspirin do not experience adequate anti-platelet effects. METHODS AND RESULTS: There is scant evidence proving that aspirin resistance has some clinical consequences. To assess the prevalence of aspirin resistance in patients with ischemic heart disease (IHD) two independent methods were used: platelet aggregation in platelet rich plasma (PRP) after induction by propylgallate (CPG), and assessment of platelet function by PFA 100 method. The study population consisted of 424 patients treated for IHD on the 2nd Dept. of Medicine, Teaching Hospital, Hradec Kralove. The age, gender, diagnosis and effect of therapy were characterized in this group of the patients. Daily ASA dose was 100 mg. We used two methods to monitor ASA treatment efficacy: a) thrombocyte aggregation after induction by CPG, b) the assessment of platelet function by PFA 100 method. a) Of the patients studied by CPG platelet aggregation, 51 (12.1%) pts were resistant to ASA dose 100 mg/day, and 32 (7.6%) pts remained resistant even after increasig the dose to 200 mg/day. In 80 (20%) pts, the daily ASA dose of less than 100 mg was sufficient to inhibit platelet function. b) Although the PFA-100 system is not able to detect the difference between low and high ASA dose, we found 53 (15.2%) patients aspirin resistant using this method. CONCLUSIONS: In the patients with IHD treated with 100 mg of ASA per day, our study has shown that the prevalence of aspirin resistance was 12.1% using CPG method, and 15.2% using PFA-100 method. Aspirin resistance was dose dependent. Prevalence of ASA resistance in patients treated with 200 mg of ASA per day was only 7.6% using the CPG method.

Adolescent↗

PubMed2004

Selectins and monocyte chemotactic peptide as the markers of atherosclerosis activity.

The role of adhesive selectin molecules in the process of atherogenesis is an open question. These molecules are known as markers of atherosclerosis activity, however, only some biological mechanisms are known up to now. In this study we examined the levels of soluble forms of E-, P-selectin and monocyte chemotactic protein (MCP-1) in the process of extracorporeal cholesterol elimination by LDL-apheresis. We measured the levels of sE-, sP-selectin and MCP-1 in the plasma before and after LDL-apheresis and in the washout solution from immunoabsorption columns Lipopak. Eighty measurements were performed repeatedly in 6 patients with severe familial hypercholesterolemia (FH) on long-term LDL-apheresis treatment. Before the procedure P-selectin levels were 204+/-179 ng/ml, E-selectin 32.1+/-33.7 ng/ml, MCP-1 323.8+/-121 pg/l, whereas after the procedure we found P-selectin levels 131.6+/-34 ng/ml, E-selectin 33.1+/-51 ng/ml, and MCP-1 200.4+/-15 pg/l. Levels of P-selectin were increased in the blood of patients with FH in spite of long-term intensive extracorporeal LDL-elimination, documenting thus the activity of atherosclerosis. The levels of P-selectin and MCP-1 decreased significantly after the hypolidemic procedure and could be used as another marker showing the effectivity of the extracorporeal LDL-cholesterol elimination (immediately after the procedure), and, after further verification, may serve as a marker for controlling the therapy efficacy.

Arteriosclerosis↗

PubMed2002

[Changes in hemostasis in malignant diseases].

Tumourous diseases are associated with haemorrhagic as well as thrombotic complications. The most frequent cause of haemorrhagic states in tumourous diseases is thrombocytopenic haemorrhage, consumption coagulopathy and activated fibrinolysis. Trousseau described in 1865 a mutual association between tumourous diseases and venous thromboembolism. As many as 15-20% patients with venous thromboembolism have an undetected malignity which is a prevalence of 2-3% in the population. From this ensues the relative risk of a newly diagnosed malignity which is higher during the first year after venous thromboembolism. The prevalence varies between 2% and 6%. Migrating thrombophlebitiis (saltans and migrans) are a relatively specific sign in tumours, in particular in pancreatic tumours. In the pathogenesis of venous thromboembolisms in tumourous diseases in particular the following factors play a part: elevated coagulation parameters, reduced fibrinolysis, frequent immobilization, surgical operations in the case-history, chemotherapy, hormonal therapy and central venous catheters. The authors present a brief review of changes of haemostasis in tumourous diseases, their possible diagnosis and possible pharmacological prevention and treatment of thromboembolisms.

Blood Coagulation Disorders↗

PubMed1992

Relationships between secondary structure fractions for globular proteins. Neural network analyses of crystallographic data sets.

The relationship between the fractions of protein secondary structural components as determined from X-ray crystallographic data by the procedures of Kabsch and Sander (KS) and of Levitt and Greer (LG) is analyzed by neural network analysis of these two tabulations of literature data. A linear relationship between the KS and LG reductions of X-ray data to secondary structure descriptors is demonstrated by a regression analysis of the relationships between these sets of structural parameters. Back-propagation neural network analysis was then used to derive equations for determination of the most probable fractions of beta-sheet, bend, turn, and "other" conformations given the fraction of alpha-helix in a globular protein. The deviation of the X-ray values for beta-sheet from that determined with these equations was shown to have a variance that exponentially decreased with increasing fraction of alpha-helix. A second neural network analysis showed that knowledge of both the alpha-helical and beta-sheet fractions in a protein significantly reduces the uncertainty in prediction of the other components of the secondary structure. These analyses provide insight into the nature of the data sets derived from crystal structures. Since these complications of crystal structure data are commonly used as reference information for quantitative evaluation of spectra (for example, FTIR, Raman, and electronic or vibrational circular dichroism) in terms of secondary structure, such internal correlations in the reference sets may have significant effects on the stability of spectroscopic analyses derived from them.

Mathematics↗

PubMed1992

The clinical significance of measuring different anti-dsDNA antibodies by using the Farr assay, an enzyme immunoassay and a Crithidia luciliae immunofluorescence test.

Anti-double-stranded DNA (dsDNA) antibodies are highly specific for the diagnosis of systemic lupus erythematosus (SLE) but are heterogeneous in respect to, for example, avidity, class and cross-reactivity. Sera from 2061 patients were measured by three methods: an enzyme-linked immunosorbent assay (ELISA), an indirect immunofluorescence test with Crithidia luciliae as substrate (CLIF), and the Farr assay, a radioimmunological method based on the ammonium sulfate precipitation of immune complexes. The different anti-dsDNA antibody determinations were evaluated by analysis of patient records. The reason for a reactive Farr assay in 14 patients was predominantly the measurement of antibodies of the IgM class, which are not detected by the ELISA. The detection of additional antibodies to dsDNA of the IgA class, to single-stranded DNA or to histones plays a minor role. In comparison with the Farr assay, we found more positive results with the ELISA, which additionally detects anti-dsDNA antibodies of low avidity. The ELISA might also yield positive values in conditions such as chronic liver diseases, various infections and connective tissue diseases other than SLE. Avoiding the disadvantages of radioactivity, the ELISA is well suited as a screening test for dsDNA antibodies. However, positive results should be confirmed by the CLIF test or preferably by the Farr assay, thus combining sensitivity with specificity.

Animals↗

PubMed1990