Študovala sa možnost tvorby primárnej membrány ako i sekundárnej retardačnej bariéry po zhustení mikročástic obalených vodnou disperziou etylcelulózy systémom Surelease fluidnou technikou (Aeromatic). Ukázalo sa, že na transformáciu práškovitého liečiva na dobre listovateľné aglomeráty je potrebný pomerne vysoký obsah polyméru (30 %). Významnejšia retardácia sa u matríc z obalených peliet dosiahla pri 20 a 30 % obsaJiu polyméru. Matrice formované z mikrodražé vykazujú výrazné spomalenie rýchlosti liberácie liečiva už pri 10 % obsahu prípravku Surelease a potvrdzujú retardačnú schopnosť etylcelulózového latexu.
The paper studies the possible formation of the primary membrane and the secondary retarding barrier after thickening the micropartides coated with an aqueous dispersion of ethylcellulose using the system Surelease with the fluid technique (Aeromatic). It has been found that for the transformation of the powdered drug into well-compressible agglomerates a relatively high content of the polymer (30 %) is needed. More significant retardation in the matrices made of coated pellets was achieved with contents of 20 % and 30 % of the polymer. Matrices formed from coated microtablets show marked deceleration of drug liberation rate already with a content of 10 % of the preparation Surelease and they confirm the retardii^ ability of ethylcellulose latex.
- Keywords
- SURELEASE,
- MeSH
- Cellulose MeSH
- Tablets, Enteric-Coated MeSH
- Pharmacokinetics MeSH
- Pentoxifylline methods MeSH
[1st ed.] 124 s. : il.
- MeSH
- Biochemistry MeSH
- Laboratories MeSH
- Proteins MeSH
- Publication type
- Textbook MeSH
- Conspectus
- Biochemie. Molekulární biologie. Biofyzika
- NML Fields
- biochemie
Cytokinins (CKs) are pivotal plant hormones that have crucial roles in plant growth and development. However, their isolation and quantification are usually challenging because of their extremely low levels in plant tissues (pmol g-1 fresh weight). We have developed a simple microscale magnetic immunoaffinity-based method for selective one-step isolation of CKs from very small amounts of plant tissue (less than 0.1 mg fresh weight). The capacity of the immunosorbent and the effect of the complex plant matrix on the yield of the rapid one-step purification were tested using a wide range of CK concentrations. The total recovery range of the new microscale isolation procedure was found to be 30-80% depending on individual CKs. Immunoaffinity extraction using group-specific monoclonal CK antibodies immobilized onto magnetic microparticles was combined with a highly sensitive ultrafast mass spectrometry-based method with a detection limit close to one attomole. This combined approach allowed metabolic profiling of a wide range of naturally occurring CKs (bases, ribosides and N9 -glucosides) in 1.0-mm sections of the Arabidopsis thaliana root meristematic zone. The magnetic immunoaffinity separation method was shown to be a simple and extremely fast procedure requiring minimal amounts of plant tissue.
OBJECTIVES: HIV-infected individuals are at higher risk of non-AIDS diseases associated with procoagulant status. Microparticles are elevated in disorders associated with thrombosis (e.g., cardiovascular diseases). We investigated the association between microparticle levels in untreated and treated HIV-infected subjects, and determined the association with immune status, viral replication, and duration of antiretroviral therapy. PATIENTS AND METHODS: We included 144 HIV-infected subjects, including 123 on antiretroviral therapy (ART) and 21 before treatment initiation. A control group of 40 HIV-negative healthy adults matched for age and sex was used for comparison of microparticle levels. Treated subjects were divided into five groups depending on the period of antiretroviral exposure. Statistically significant differences were determined by Kruskal-Wallis test and Chi2 test. The relation between microparticles and other parameters was assessed using Spearman's coefficient of correlation. RESULTS: Microparticle levels were significantly higher in treated and untreated HIV-infected subjects than in non-HIV-infected controls (P<0.001). The microparticle level was similar between the groups on treatment (P=0.913). No association between the microparticle level and CD4+ count, CD4+/CD8+ ratio, number of HIV-1 RNA copies, or duration of exposure to antiretroviral treatment was observed. CONCLUSION: Increased levels of microparticles may be due to processes independent of viral replication and CD4+ cell count, and microparticle release might persist even during viral suppression by antiretroviral treatment. Elevated microparticle levels might occur in response to other triggers.
- MeSH
- Adult MeSH
- Blood Coagulation * MeSH
- HIV Infections blood MeSH
- Middle Aged MeSH
- Humans MeSH
- Cell-Derived Microparticles * MeSH
- Young Adult MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Total gentamicin is a sum of five congeners C1, C1a, C2, C2a and minor C2b, which differ from each other in their methylation on the purpurosamine ring. Liquid chromatography with mass detection (LC-MS/MS) and specified calibration material enables the concentration of total gentamicin and its individual congeners to be analysed. METHODS: 50 µL serum was precipitated with acetonitrile in the presence of 0.5 mol/L formic acid. A RP BEH C18 1.7 µm 2.1x50 mm column maintained at 30 °C and tobramicin as the internal standard were used. Mass detection was performed in positive electrospray. The gentamicin results were compared with fluorescence polarization immunoassay (FPIA) and chemiluminiscent microparticle immunoassay (CMIA). Passing-Bablock regression analysis and Bland-Altman analysis were used. RESULTS: Calibration curves for individual gentamicin congeners were linear with correlation coefficients between 0.997 and 0.998. Recovery was 91.6-102.0% and the coefficients of variation 1.4-8.4%. The total gentamicin concentration was compared with immunoassay FPIA (LC-MSgen = 0.9798xPFIAgen) and CMIA (LC MSgen = 0.9835xCMIAgen) both with significant correlation (p < 0.001). CONCLUSION: The LC-MS/MS method is fast and precise and can be applied to routine TDM in patients. Comparing it to immunoassays makes it possible to measure concentration of gentamicin congeners, which may be important in the case of their different pharmacokinetics.
OBJECTIVES: Tissue factor (TF) is a main initiator of coagulation cascade. Its determination in conditions of acute coronary syndrome is logistically difficult. Hence, in our study, the activity and the concentration of TF and the count of microparticles in the platelet free plasma (PFP) were determined. METHODS: Blood was drawn from both coronary sinus and femoral vein circulation in a cohort of 40 patients. TF activity was measured by activation of factor X in the presence of factor VIIa, whereas microparticles were detected using flow cytometry. TF antigen concentrations were determined using the ELISA test. RESULTS: TF activity in the stable angina subgroup was not significantly different from the control group (18.12 +/- 3.35 mOD/min vs. 17.72 +/- 4.05 mOD/min, respectively), but it was significantly lower in the unstable angina (7.62 +/- 4.19 mOD/min) and myocardial infarction (MI) (3.56 +/- 3.85 mOD/min) subgroups (P < 0.05). Results from the coronary sinus and femoral vein circulations were not significantly different. The count of microparticles decreased according to the severity of the acute coronary syndrome: control group, 520 +/- 172; stable angina subgroup, 532 +/- 167; unstable angina subgroup, 392 +/- 142; and MI subgroup, 165 +/- 30 (P < 0.05). There were no significant differences in concentrations of TF antigen in four subgroups. CONCLUSIONS: These results suggest that the procoagulant TF-bearing microparticles could be recruited from PFP by interaction with platelets and blood cells in the conditions of acute coronary syndrome.
- MeSH
- Acute Coronary Syndrome blood MeSH
- Autoantigens blood MeSH
- Enzyme-Linked Immunosorbent Assay MeSH
- Financing, Organized MeSH
- Cohort Studies MeSH
- Middle Aged MeSH
- Humans MeSH
- Pilot Projects MeSH
- Prospective Studies MeSH
- Aged MeSH
- Thromboplastin analysis immunology MeSH
- Blood Platelets MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
Microparticles are small membrane fragments with dimension between 0.1 and 1 μm, which are released during cell activation or apoptosis, exposing the phospholipid phosphatidylserine and membrane antigens typical for cellular origin. Philadelphia-negative myeloproliferative neoplasms (MPNs) are characterized by an increased risk of thrombosis. Data from literature suggest an association between thrombosis and the procoagulant activity of microparticles. Association between the procoagulant activity of microparticles and the incidence of thrombosis was assesed in a group of 126 patients with Philadelphia-negative MPNs. Measurement of microparticles procoagulant activity was performed using a functional assay, namely the Zymuphen MP-activity (Hyphen Biomed, Neuville-sur-oise, France). A total of 539 samples were analysed within this group of patients, regardless of patients' state of health. A significantly higher circulating microparticles procoagulant activity was found in MPN patients as compared with the control group (P < 0.001). A pathological level of procoagulant activity was observed more frequently in patients with polycythaemia vera (88%, P = 0.002) than groups of patients with essential thrombocythaemia (73.2%) and primary myelofibrosis (68.3%); the same result was confirmed in patients with a history of venous thrombosis in comparison with patients without thrombosis (84.7 vs. 73.2%, P = 0.029). Patients without cytoreductive treatment had a higher activity of microparticles (P = 0.010). Furthermore, presence of JAK2 V617F mutation was associated with an increased procoagulant activity (P = 0.007), as well as the higher JAK2 V617F allele burden (P = 0.001). Further prospective clinical studies will be necessary to evaluate the clinical relevance of microparticles in the prediction hypercoagulable state in these patients.
- MeSH
- Incidence MeSH
- Middle Aged MeSH
- Humans MeSH
- Cell-Derived Microparticles pathology MeSH
- Myeloproliferative Disorders blood complications pathology MeSH
- Polycythemia Vera blood complications pathology MeSH
- Thrombosis blood etiology pathology MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
BACKGROUND/AIM: This work aimed to prospectively evaluate the clinical significance of circulating microparticles (MPs) in relation to thrombotic risk factors and thrombotic complications in patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN). PATIENTS AND METHODS: In a cohort of 206 patients with MPN, MPs' procoagulant activity was measured by the Zymuphen functional assay in 429 samples, while platelet- and erythrocyte-MPs were enumerated by flow cytometry in 558 samples. RESULTS: MPN patients had higher MP levels than the control group. The levels of MPs were higher in male patients, smokers, and those who were older than 60 years, and in the presence of JAK2V617F mutation, history of thrombosis, platelets >400×109/l, hematocrit >45%, or leukocytes >10×109/l. Cytoreductive treatment reduced MP levels, with anagrelide being associated with lower MP levels than hydroxyurea. CONCLUSION: The relationship with thrombotic risk factors indicates a possible role of MPs in the complex thrombotic mechanism, though cytoreductive treatment seems to affect this role through reducing MP levels.
- MeSH
- Humans MeSH
- Cell-Derived Microparticles * MeSH
- Myeloproliferative Disorders * drug therapy genetics MeSH
- Neoplasms * MeSH
- Blood Platelets MeSH
- Thrombosis * etiology genetics MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
OBJECTIVES: Recent technological breakthroughs in the design of reliable systems for long term non-pulsatile mechanical heart support offer the possibility to study the effect of continuous blood flow in the vascular system. Generally, it is assumed that the absence of physiological pulsatile flow leads to prothrombogenic and proatherogenic changes. We investigated the change in the circulating endothelial microparticle concentration as a marker of endothelial damage in patients implanted with a continuous-flow left ventricle assist device (LVAD). METHODS: Endothelial microparticles were measured in 8 males (mean age 54.1±11.5 years) with terminal heart failure before and 3 months after implantation of an LVAD. The group consisted of 3 patients with dilated cardiomyopathy, 3 patients with ischemic cardiomyopathy, 1 patient with both conditions and 1 patient with congenital valvular disease. The concentration of endothelial microparticles was determined by ELISA Zymutest MP activity test. RESULTS: We did not observe a significant change in the concentration of circulating endothelial microparticles measured before and 3 months after implantation (p=0.669). High inter-individual variability in response to implantation was found. However, no association between a change in endothelial microparticle concentration and heart failure aetiology or a significant clinical complication attributed to LVAD implantation was observed. CONCLUSION: Results from this preliminary pilot study do not indicate that LVADs contribute to short-term vascular damage as defined by an increase in circulating endothelial microparticles.
- MeSH
- Biomarkers blood MeSH
- Endothelium, Vascular metabolism pathology MeSH
- Cardiomyopathy, Dilated blood surgery MeSH
- Adult MeSH
- Hemodynamics physiology MeSH
- Myocardial Ischemia blood surgery MeSH
- Middle Aged MeSH
- Humans MeSH
- Cell-Derived Microparticles metabolism pathology MeSH
- Pilot Projects MeSH
- Heart-Assist Devices adverse effects MeSH
- Prospective Studies MeSH
- Aged MeSH
- Heart Failure blood surgery MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Publication type
- Journal Article MeSH
- Clinical Trial MeSH
- Research Support, Non-U.S. Gov't MeSH
