21 results on '"Mazoch J"'
Search Results
2. Control of gene expression by FNR-like proteins in facultatively anaerobic bacteria
- Author
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Mazoch, J. and Kučera, I.
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- 2002
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3. Adiponectin, AFABP, and leptin in human breast milk during 12 months of lactation.
- Author
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Bronsky J, Mitrova K, Karpisek M, Mazoch J, Durilova M, Fisarkova B, Stechova K, Prusa R, and Nevoral J
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- 2011
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4. Specific treatment of pheochromocytoma decreases high-sensitive CRP concentrations
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Petrak, O., Jiri Widimsky, Zelinka, T., Mazoch, J., Kvasnicka, J., Strauch, B., Holaj, R., Stulc, T., and Skrha, J.
5. Microvascular Reactivity and Endothelial Function in Type 2 Diabetic Patients with Hyperlipidemia Treated with Simvastatin: 3-year Follow-up
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Prázný, M., Zdislava Krupičková, Mazoch, J., Kvasnicka, J., and Skrha, J.
6. [Thrombotic complications of sepsis and their pharmacological prophylaxis]
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Zenáhlíková Z, Výborný J, Uchytil Z, Zdeněk Krška, Mazoch J, Malíková I, and Kvasnicka J
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Venous Thrombosis ,Sepsis ,Humans ,Pulmonary Embolism ,Blood Coagulation - Abstract
Patients with severe sepsis are at increased risk for developing thrombembolic phenomena. This article aims to clarify the association between systemic inflammation activation and coagulation, pathogenesis of coagulation abnormalities during severe sepsis. The article reviews incidence and deep venous thrombosis risk factors among these patients and summarizes recent evidence-based guidelines for deep venous thrombosis prophylaxis.
7. Thrombembolic complications of sepsis and their pharmacological prophylaxis | Trombotické komplikace při sepsi a jejich farmakologická profylaxe
- Author
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Zenáhlíková, Z., Josef Vyborny, Uchytil, Z., Krška, Z., Mazoch, J., Malíková, I., and Kvasnička, J.
8. Fermentor of 200 m3 with direct stirrer drive developed in research institute of chemical equipment CHEPOS for fodder yeast production.
- Author
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SEICHTER, P., primary, PEŠL, L., additional, SLÁMA, V., additional, VÁTEK, O., additional, and MAZOCH, J., additional
- Published
- 1986
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9. Prognostic significance of surfactant protein A, surfactant protein D, Clara cell protein 16, S100 protein, trefoil factor 3, and prostatic secretory protein 94 in idiopathic pulmonary fibrosis, sarcoidosis, and chronic pulmonary obstructive disease.
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Doubková M, Karpíšek M, Mazoch J, Skřičková J, and Doubek M
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- Adult, Aged, Biomarkers blood, Bronchoalveolar Lavage Fluid chemistry, Case-Control Studies, Diagnosis, Differential, Female, Humans, Idiopathic Pulmonary Fibrosis blood, Idiopathic Pulmonary Fibrosis mortality, Lung diagnostic imaging, Lung physiopathology, Male, Multivariate Analysis, Predictive Value of Tests, Prognosis, Pulmonary Disease, Chronic Obstructive blood, Pulmonary Disease, Chronic Obstructive mortality, Sarcoidosis, Pulmonary blood, Sarcoidosis, Pulmonary mortality, Severity of Illness Index, Spirometry, Tomography, X-Ray Computed, Idiopathic Pulmonary Fibrosis diagnosis, Lung metabolism, Prostatic Secretory Proteins blood, Pulmonary Disease, Chronic Obstructive diagnosis, Pulmonary Surfactant-Associated Protein A blood, Pulmonary Surfactant-Associated Protein D blood, S100 Proteins blood, Sarcoidosis, Pulmonary diagnosis, Trefoil Factor-3 blood, Uteroglobin blood
- Abstract
Background: Identification of serum and bronchoalveolar lavage fluid (BALF) biomarkers may facilitate diagnosis and prognostication in various lung disorders., Objective: Serum and BALF levels of surfactant protein A (SP-A), surfactant protein D (SP-D), Clara cell protein 16 (CC16), S100 protein, trefoil factor 3 (TFF3), and prostatic secretory protein 94 (PSP94) were evaluated in 94 consecutive patients (idiopathic pulmonary fibrosis (IPF; n=18), sarcoidosis (n=25), chronic obstructive pulmonary disease (COPD; n=51)), and in 155 healthy controls., Methods: Biomarkers were measured at diagnosis and compared with disease characteristics. Both uniparametric and multiparametric analyses were used., Results: Seven significant correlations were found: 1) BALF PSP94 level correlated with prognosis of sarcoidosis (P=0.035); 2) BALF SP-D level with pulmonary functions in IPF (P=0.032); 3) BALF SP-D and TFF3 with IPF mortality (P=0.049 and 0.017, respectively); 4) serum TFF3 level with COPD mortality (P=0.006,); 5) serum SP-A with pulmonary functions impairment in IPF (P=0.011); 6) serum SP-D level was associated with HRCT interstitial score in IPF (P=0.0346); and 7) serum SP-A was associated with staging of COPD according to spirometry (P<0.001). Moreover, our analysis showed that some biomarker levels differed significantly among the diseases: 1) BALF SP-D level differed between sarcoidosis and IPF; 2) serum SP-A level differed among IPF, sarcoidosis, COPD and was also different from healthy controls; 3) serum S100A6, S100A11 levels differed among IPF, sarcoidosis, COPD from healthy controls 4) serum SP-D, CC16, TFF-3 levels distinguished IPF patients from healthy controls; and 5) serum CC16, TFF3, PSP94 distinguished COPD patients from healthy controls. Our study shows that some of selected biomarkers should have prognostic value in the analysed lung disorders. On the other hand, these biomarkers do not appear to be unequivocally suitable for differential diagnosis of these disorders.
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- 2016
10. Acute hyperglycemia does not impair microvascular reactivity and endothelial function during hyperinsulinemic isoglycemic and hyperglycemic clamp in type 1 diabetic patients.
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Horová E, Mazoch J, Hiigertová J, Kvasnička J, Skrha J, Soupal J, and Prázný M
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- Adult, Blood Glucose metabolism, Calibration, Diabetes Complications pathology, Diabetes Mellitus, Type 1 physiopathology, Diabetes Mellitus, Type 1 therapy, Endothelium, Vascular cytology, Humans, Hyperglycemia therapy, Insulin metabolism, Laser-Doppler Flowmetry methods, Microcirculation, Middle Aged, Oxidative Stress, Perfusion, Glucose Clamp Technique, Hyperglycemia physiopathology
- Abstract
Aims: The aim of this study was to evaluate the effect of acute glycemia increase on microvasculature and endothelium in Type 1 diabetes during hyperinsulinemic clamp., Patients and Methods: Sixteen patients (51 ± 7 yrs) without complications were examined during iso- and hyperglycemic clamp (glucose increase 5.5 mmol·L(-1)). Insulin, lipid parameters, cell adhesion molecules and fibrinogen were analyzed. Microvascular reactivity (MVR) was measured by laser Doppler flowmetry., Results: Maximum perfusion and the velocity of perfusion increase during PORH were higher in hyperglycemia compared to baseline (47 ± 16 versus 40 ± 16 PU, P < 0.01, and 10.4 ± 16.5 versus 2.6 ± 1.5 PU·s(-1), P < 0.05, resp.). Time to the maximum perfusion during TH was shorter and velocity of perfusion increase during TH higher at hyperglycemia compared to isoglycemic phase (69 ± 15 versus 77 ± 16 s, P < 0.05, and 1.4 ± 0.8 versus 1.2 ± 0.7 PU·s(-1), P < 0.05, resp.). An inverse relationship was found between insulinemia and the time to maximum perfusion during PORH (r = -0.70, P = 0.007)., Conclusion: Acute glycemia did not impair microvascular reactivity in this clamp study in Type 1 diabetic patients. Our results suggest that insulin may play a significant role in the regulation of microvascular perfusion in patients with Type 1 diabetes through its vasodilation effect and can counteract the effect of acute glucose fluctuations.
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- 2012
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11. Influence of long-term thromboprophylaxis with low-molecular-weight heparin (enoxaparin) on changes of bone metabolism markers in pregnant women.
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Sudrová M, Kvasnička J, Kudrnová Z, Zenáhlíková Z, Mazoch J, and Brzežková R
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- Adult, Alkaline Phosphatase blood, Anticoagulants adverse effects, Enoxaparin adverse effects, Female, Gestational Age, Humans, Osteoprotegerin blood, Pregnancy, Pregnancy Trimesters blood, RANK Ligand blood, Retrospective Studies, Anticoagulants administration & dosage, Bone and Bones metabolism, Enoxaparin administration & dosage, Pregnancy Complications, Hematologic blood, Pregnancy Complications, Hematologic prevention & control, Thrombophilia blood, Thrombophilia prevention & control
- Abstract
This is a first descriptive, retrospective, observational study aiming to evaluate the changes in bone turnover markers in pregnant women and to assess the effect of a long-term treatment with low-molecular-weight heparin (LMWH), specifically, enoxaparin. Study involved 50 pregnant Caucasian women with thrombophilia. The patients either received prophylactic enoxaparin once daily subcutaneously (N = 35) or were observed without treatment (N = 15). Concentrations of total serum alkaline phosphatase (total AP), bone alkaline phosphatase (bone AP), osteoprotegerin (OPG), and the receptor activator of nuclear factor κB ligand (RANKL) were measured at 15, 25, and 35 weeks of gestation. Total serum AP increased with gestational age. In the group treated with enoxaparin, the percentage of bone AP concentration was lower (P < .05) than in the control group. Serum OPG also increased with gestational age, but no significant difference was found between the groups with- and without treatment. Despite the OPG increased, RANKL did not change.
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- 2011
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12. FXa inhibition and coagulation changes during DVT prophylaxis by enoxaparin over the course of a 15-day follow-up in septic patients.
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Zenáhlíková Z, Kvasnicka J, Kudrnová Z, Sudrová M, Brzezková R, Mazoch J, Malíková I, Vyborny J, Erhart D, and Pecen L
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- Adult, Aged, Aged, 80 and over, Humans, Male, Middle Aged, Anticoagulants therapeutic use, Blood Coagulation drug effects, Enoxaparin therapeutic use, Factor Xa Inhibitors, Sepsis blood, Venous Thrombosis blood, Venous Thrombosis prevention & control
- Abstract
The objective of our study was to examine the changes in coagulation parameters and inflammatory reaction over the course of 15 days in patients with severe sepsis. We tried to identify mechanisms by which sepsis-induced pathophysiological changes may influence the effectiveness of subcutaneously (SC) administered enoxaparin 40 mg once daily. A total of 16 patients (8 men, 8 women; age 35-83 years) meeting the inclusion criteria of severe sepsis were enrolled in this study. The follow-up was performed on days 1, 2, 3, 6, 9, 12, and 15 of hospitalization at the intensive care unit (ICU). Blood coagulation (activated partial thromboplastin time [aPTT], prothrombin time [PT], fibrinogen, antithrombin (AT), protein C [PC], D-dimer, fragment 1.2 [F1.2], factor Xa [FXa] inhibition) and inflammatory reactants (interleukin 6 [IL-6], C-reactive protein [CRP], orosomucoid, alpha-1-antitrypsin) were tested. The mean FXa inhibition was 0.17 (+ or - 0.17) IU/mL. The arbitrarily established range of FXa inhibition for prophylaxis, 0.2 to 0.4 IU/mL, was reached in 22 cases (20%), while in 74 cases (68%), it was below and in 13 cases (12%) above the aforementioned range. Factor Xa inhibition positively correlated with AT (r = .42; P < .001) and PC (r = .45; P < .001) activities. A negative correlation was found between the FXa inhibition and alpha-1-antitrypsin concentrations (r = -.33; P = .01) but only in the subgroup with alpha-1-antitrypsin concentrations > or = 2.2 g/L. We confirmed that in most patients with sepsis, the prophylaxis with enoxaparin did not lead to the required FXa inhibition. The inhibition of FXa by enoxaparin depends mainly on the AT and PC activities.
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- 2010
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13. Older age and type of surgery predict the early inflammatory response to hip trauma mediated by interleukin-6 (IL-6).
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Sedlár M, Kudrnová Z, Erhart D, Trca S, Kvasnicka J, Krska Z, Mazoch J, Malíková I, Zeman M, and Linhart A
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- Aged, Female, Humans, Male, Postoperative Complications, Survival Rate, Hip Fractures metabolism, Hip Fractures mortality, Hip Fractures surgery, Inflammation epidemiology, Inflammation metabolism, Inflammation pathology, Interleukin-6 metabolism, Surgical Procedures, Operative classification, Surgical Procedures, Operative statistics & numerical data
- Abstract
Hip trauma and surgery are associated with systemic inflammatory reaction. However, little evidence exists about the role of IL-6. In order to assess the inflammatory response, we evaluated white blood cell (WBC) count, C-reactive protein (CRP) and IL-6 dynamics in sequential pre- and postsurgical samples collected from 125 elderly patients (mean age 78+/-9 years) undergoing osteosynthesis (OS) for extracapsular hip fractures (n=69), hemiarthroplasty (HA) or urgent total hip arthroplasty for intracapsular fractures (UA) (n=35), and elective total hip arthroplasty for osteoarthrosis (OA) (n=21). Both preoperative CRP and IL-6 levels were higher in patients with intracapsular fractures. IL-6 levels reached peak values immediately after the surgery, while CRP peak levels were reached 48 h after the surgery. The overall inflammatory reaction was more intense in HA patients compared to the other subgroups. Independent of each other, older age and the hip fracture type affected the IL-6 response, while the CRP response depended only on the type of surgery. The abrupt increase in IL-6 immediately after the procedure suggests its involvement in the early stages of the postoperative inflammatory reaction after hip surgery. This reaction is particularly pronounced in elderly patients receiving HA., (Copyright 2009 Elsevier Ireland Ltd. All rights reserved.)
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- 2010
- Full Text
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14. Favorable coagulation profile with fondaparinux after hip surgery in elderly patients.
- Author
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Kudrnová Z, Kvasnička J, Kudrna K, Mazoch J, Malíková I, Zenáhlíková Z, Sudrová M, and Brzežková R
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- Acute-Phase Proteins analysis, Aged, Aged, 80 and over, Anticoagulants administration & dosage, Blood Coagulation Tests, Female, Fondaparinux, Hip Fractures blood, Humans, Inflammation Mediators blood, Injections, Subcutaneous, Male, Polysaccharides administration & dosage, Time Factors, Anticoagulants therapeutic use, Blood Coagulation drug effects, Factor Xa Inhibitors, Hip Fractures surgery, Polysaccharides therapeutic use, Postoperative Complications prevention & control, Venous Thromboembolism prevention & control
- Abstract
Twenty-three patients with fondaparinux prophylaxis over 75 years of age who underwent hip fracture surgery were enrolled in the study. Fondaparinux sodium (2.5 mg) was administered subcutaneously 6 h postoperatively and then every 24 h for 28 days. Coagulation and inflammatory parameters were measured preoperatively, then 10 h, 2, 7, and 28 days postoperatively. Increased D-dimers, positive acute phase proteins, and IL-6, and decreased negative acute phase proteins were observed preoperatively (P < 0.05). Maximum values were reached 10 h postoperatively for IL-6 and D-dimer, and on postoperative days 2 and 7 for positive acute phase proteins (P < 0.05). Transferrin, prealbumin and antithrombin levels were lowest 10 h postoperatively and on postoperative day 2 (P < 0.05). Increased D-dimers, IL-6, and positive acute phase proteins, and decreased negative acute phase proteins persisted until postoperative day 28 (P < 0.05). Prothrombin fragments (F1 + 2) reached peak levels preoperatively and decreased gradually until postoperative day 28. Fondaparinux promoted the inhibition of thrombin generation, as documented by negative correlation between F1 + 2 and FXa inhibition (r = -0.46; P < 0.001). Fondaparinux-induced FXa inhibition increased gradually until postoperative day 28. This increase correlated positively with antithrombin activity (r = 0.4; P < 0.05). Fondaparinux prophylaxis counteracted pro-thrombogenic effect associated with hip fracture and subsequent surgery without severe bleeding complications.
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- 2009
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15. Microvascular Reactivity and Endothelial Function in Type 2 Diabetic Patients with Hyperlipidemia Treated with Simvastatin: 3-year Follow-up.
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Prázný M, Kasalová Z, Mazoch J, Kvasnicka J, and Skrha J
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- Cell Adhesion Molecules blood, Diabetes Mellitus, Type 2 blood, Diabetes Mellitus, Type 2 complications, Female, Humans, Hyperlipidemias blood, Hyperlipidemias complications, Laser-Doppler Flowmetry, Lipids blood, Male, Middle Aged, Skin blood supply, Vasodilation physiology, Diabetes Mellitus, Type 2 physiopathology, Endothelium, Vascular physiopathology, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Hyperlipidemias drug therapy, Hypolipidemic Agents therapeutic use, Microcirculation physiology, Simvastatin therapeutic use
- Abstract
Aim of this study was to evaluate microvascular reactivity (MVR) by laser Doppler flowmetry in Type 2 diabetes mellitus (T2DM) with hyperlipidemia during three years of simvastatin treatment. Additionally, markers of endothelium and fibrinolysis were evaluated. Twenty patients with T2DM and hyperlipidemia were treated with 20 mg of simvastatin daily for 3 months, treatment was then interrupted for 3 months (wash-out) and again started and maintained continually up to total of 36 months of follow-up. Maximal perfusion (max), velocity of perfusion increase (max/t) and percent increase of perfusion compared to baseline (%) was measured during post-occlusive reactive hyperemia (PORH) and thermal hyperemia (TH). VCAM-1, ICAM-1, E-selectin and P-selectin were used as markers of endothelium, tissue plasminogen activator (tPA) and its inhibitor (PAI-1) as markers of fibrinolysis. Baseline MVR in diabetic patients was comparable to controls. MVR decreased at months 3, 12, and 36 compared to baseline (PORHmax 26+/-12, 35+/-17, 26+/-11 vs. 56+/-30 PU, p<0.05, THmax 67+/-19, 81+/-37, 58+/-24 vs. 134+/-70 PU, p<0.01, PORHmax/t 2.0+/-1.4, 2.8+/-1.7, 1.9+/-1.3 vs. 7.7+/-7.4 PU/s, p<0.05, THmax/t 1.1+/-0.6, 1.0+/-0.4, 0.7+/-0.4 vs. 1.5+/-0.7 PU/s, p<0.05.
- Published
- 2009
16. [Thrombotic complications of sepsis and their pharmacological prophylaxis].
- Author
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Zenáhlíková Z, Výborný J, Uchytil Z, Krska Z, Mazoch J, Malíková I, and Kvasnicka J
- Subjects
- Blood Coagulation, Humans, Pulmonary Embolism prevention & control, Sepsis blood, Venous Thrombosis prevention & control, Pulmonary Embolism etiology, Sepsis complications, Venous Thrombosis etiology
- Abstract
Patients with severe sepsis are at increased risk for developing thrombembolic phenomena. This article aims to clarify the association between systemic inflammation activation and coagulation, pathogenesis of coagulation abnormalities during severe sepsis. The article reviews incidence and deep venous thrombosis risk factors among these patients and summarizes recent evidence-based guidelines for deep venous thrombosis prophylaxis.
- Published
- 2007
17. Elevated inflammation markers in pheochromocytoma compared to other forms of hypertension.
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Zelinka T, Petrák O, Strauch B, Holaj R, Kvasnicka J, Mazoch J, Pacák K, and Widimský J Jr
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- Adrenal Gland Neoplasms complications, Adrenal Gland Neoplasms physiopathology, Adult, C-Reactive Protein analysis, Female, Fibrinogen analysis, Humans, Hyperaldosteronism blood, Hyperaldosteronism complications, Hyperaldosteronism physiopathology, Hypertension blood, Inflammation complications, Leukocyte Count, Male, Middle Aged, Neutrophils, Orosomucoid analysis, Pheochromocytoma complications, Pheochromocytoma physiopathology, Platelet Count, Prealbumin analysis, Transferrin analysis, alpha 1-Antitrypsin blood, alpha-Macroglobulins analysis, Adrenal Gland Neoplasms blood, Biomarkers blood, Hypertension etiology, Inflammation blood, Pheochromocytoma blood
- Abstract
Objective: To investigate the effect of long-term catecholamine excess in pheochromocytoma on leukocyte and platelet count and on proteins of acute-phase response., Methods: Fifteen subjects with pheochromocytoma, 16 with primary aldosteronism, 18 with essential hypertension and 17 healthy controls were studied. Sixteen subjects with pheochromocytoma were investigated after tumor removal. Leukocyte, neutrophil and platelet count, as well as C-reactive protein were measured in all subjects, while fibrinogen, alpha(1)-antitrypsin, alpha(2)-macroglobulin, orosomucoid, transferrin and prealbumin were only measured in subjects with pheochromocytoma, primary aldosteronism and essential hypertension., Results: Subjects with pheochromocytoma showed significantly higher leukocyte [7.5 +/- 0.9 10(9)/l, p < 0.001 vs. primary aldosteronism (5.4 +/- 0.9 10(9)/l) and healthy controls (5 +/- 0.9 10(9)/l), p = 0.04 vs. essential hypertension (6.3 +/- 1.6 10(9)/l)], neutrophil (p < 0.001 vs. primary aldosteronism and healthy subjects) and platelet counts (p < 0.001 vs. primary aldosteronism; p = 0.01 vs. essential hypertension) compared to the other groups of subjects. Similar results were obtained for positive proteins of acute-phase response in subjects with pheochromocytoma [C-reactive protein: 0.62 +/- 0.52 mg/dl, p < 0.001 vs. healthy subjects (0.08 +/- 0.08 mg/dl), p = 0.001 vs. primary aldosteronism (0.17 +/- 0.19 mg/dl), p = 0.04 vs. essential hypertension (0.31 +/- 0.26 mg/dl); fibrinogen: p = 0.02 vs. primary aldosteronism; orosomucoid: p = 0.005 vs. primary aldosteronism; alpha(2)-macroglobulin: p = 0.009 vs. primary aldosteronism]. No significant differences were found in plasma levels of alpha(1)-antitrypsin, transferrin and prealbumin. Tumor removal led to a significant decrease in leukocyte (p = 0.004), neutrophil (p = 0.007) and platelet count (p = 0.003) and also to a significant decrease in acute-phase proteins (C-reactive protein: p = 0.03, fibrinogen: p = 0.008, alpha(1)-antitrypsin: p = 0.003, orosomucoid: p = 0.04)., Conclusions: Chronic catecholamine excess in pheochromocytoma is accompanied by an increase in inflammation markers which was reversed by the tumor removal., (Copyright 2007 S. Karger AG, Basel.)
- Published
- 2007
- Full Text
- View/download PDF
18. [Thrombophilia in pregnancy--physiology and pathophysiology of hemocoagulation changes during normal and pathological gravidity].
- Author
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Sudrová M, Kvasnicka J, Linhartová P, and Mazoch J
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- Blood Coagulation, Female, Hemostasis, Humans, Pregnancy, Pregnancy Complications, Hematologic blood, Risk Factors, Thrombophilia blood, Venous Thromboembolism blood, Pre-Eclampsia blood, Pregnancy Complications, Hematologic physiopathology, Venous Thromboembolism physiopathology
- Abstract
Venous thromboembolism belongs to most feared complications in pregnancy. It is the leading cause of illness and even death during pregnancy and puerperium. Thrombophilias--acquired or inherited, manifest often during pregnancy and puerperium. These risk states could endanger normal pregnancy by increasing the probability of the first or recurrent thromboembolic incident and adverse obstetric events (pregnancy loss, pre-eclampsia, intrauterine growth restriction, placental abruption).
- Published
- 2007
19. Isolation and biochemical characterization of two soluble iron(III) reductases from Paracoccus denitrificans.
- Author
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Mazoch J, Tesarík R, Sedlácek V, Kucera I, and Turánek J
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- Amino Acid Sequence, Anion Exchange Resins, Catalysis, Chromatography, Ion Exchange, Electrophoresis, Polyacrylamide Gel, FMN Reductase chemistry, FMN Reductase metabolism, Isoenzymes chemistry, Isoenzymes metabolism, Kinetics, Mass Spectrometry, Molecular Sequence Data, Molecular Weight, Sequence Homology, Amino Acid, Solubility, FMN Reductase isolation & purification, Isoenzymes isolation & purification, Paracoccus denitrificans enzymology
- Abstract
Two soluble enzymes (FerA and FerB) catalyzing the reduction of a number of iron(III) complexes by NADH, were purified to near homogeneity from the aerobically grown iron-limited culture of Paracoccus denitrificans using a combination of anion-exchange chromatography (Sepharose Q), chromatofocusing (Mono P), and gel permeation chromatography (Superose 12). FerA is a monomer with a molecular mass of 19 kDa, whereas FerB exhibited a molecular mass of about 55 kDa and consists of probably two identical subunits. FerA can be classified as an NADH:flavin oxidoreductase with a sequential reaction mechanism. It requires the addition of FMN or riboflavin for activity on Fe(III) substrates. In these reactions, the apparent substrate specificity of FerA seems to stem exclusively from different chemical reactivities of Fe(III) compounds with the free reduced flavin produced by the enzyme. Observations on reducibility of Fe(III) chelated by vicinal dihydroxy ligands support the view that FerA takes part in releasing iron from the catechol type siderophores synthesized by P. denitrificans. Contrary to FerA, the purified FerB contains a noncovalently bound redox-active FAD coenzyme, can utilize NADPH in place of NADH, does not reduce free FMN at an appreciable rate, and gives a ping-pong type kinetic pattern with NADH and Fe(III)-nitrilotriacetate as substrates. FerB is able to reduce chromate, in agreement with the fact that its N-terminus bears a homology to the previously described chromate reductase from Pseudomonas putida. Besides this, it also readily reduces quinones like ubiquinone-0 (Q0) or unsubstituted p-benzoquinone.
- Published
- 2004
- Full Text
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20. Fine-tuned regulation by oxygen and nitric oxide of the activity of a semi-synthetic FNR-dependent promoter and expression of denitrification enzymes in Paracoccus denitrificans.
- Author
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Mazoch J, Kuňák M, Kučera I, and van Spanning RJM
- Subjects
- Bacterial Proteins genetics, Bacterial Proteins metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Gene Expression Regulation, Bacterial drug effects, Gene Expression Regulation, Enzymologic drug effects, Genes, Bacterial, Genes, Reporter, Lac Operon, Mutation, Nitric Oxide metabolism, Nitroprusside pharmacology, Oxidoreductases metabolism, Oxygen metabolism, Paracoccus denitrificans drug effects, Promoter Regions, Genetic, Trans-Activators genetics, Trans-Activators metabolism, Transcription Factors genetics, Transcription Factors metabolism, beta-Galactosidase genetics, Paracoccus denitrificans genetics, Paracoccus denitrificans metabolism
- Abstract
In Paracoccus denitrificans at least three fumarate and nitrate reductase regulator (FNR)-like proteins [FnrP, nitrite and nitric oxide reductases regulator (NNR) and NarR] control the expression of several genes necessary for denitrifying growth. To gain more insight into this regulation, beta-galactosidase activity from a plasmid carrying the lacZ gene fused to the Escherichia coli melR promoter with the consensus FNR-binding (FF) site was examined. Strains defective in the fnrP gene produced only very low levels of beta-galactosidase, indicating that FnrP is the principal activator of the FF promoter. Anoxic beta-galactosidase levels were much higher relative to those under oxic growth and were strongly dependent on the nitrogen electron acceptor used, maximal activity being promoted by N(2)O. Additions of nitrate or nitroprusside lowered beta-galactosidase expression resulting from an oxic to micro-oxic switch. These results suggest that the activity of FnrP is influenced not only by oxygen, but also by other factors, most notably by NO concentration. Observations of nitric oxide reductase (NOR) activity in a nitrite-reductase-deficient strain and in cells treated with haemoglobin provided evidence for dual regulation of the synthesis of this enzyme, partly independent of NO. Both regulatory modes were operative in the FnrP-deficient strain, but not in the NNR-deficient strain, suggesting involvement of the NNR protein. This conclusion was further substantiated by comparing the respective NOR promoter activities.
- Published
- 2003
- Full Text
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21. Detection, with a pH indicator, of bacterial mutants unable to denitrify.
- Author
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Mazoch J and Kucera I
- Subjects
- Acetylene pharmacology, Antimycin A pharmacology, Conjugation, Genetic, DNA Transposable Elements genetics, Hydrogen-Ion Concentration, Indicators and Reagents chemistry, Mutagenesis genetics, Nitrates metabolism, Nitrites metabolism, Oxidoreductases antagonists & inhibitors, Paracoccus denitrificans enzymology, Paracoccus denitrificans metabolism, Antimycin A analogs & derivatives, Nitrates analysis, Nitrites analysis, Paracoccus denitrificans genetics, Phenolsulfonphthalein chemistry
- Abstract
In order to facilitate isolation of mutants with alterations in the denitrification pathway, a new screening procedure using phenol red incorporated into agar overlay has been defined. Alkalinization in the neighbourhood of denitrifying colonies respiring nitrate or nitrite gives rise to a red circular halo. Antimycin blocked these colour changes, which suggests their association with the periplasmic reduction of nitrite. Inhibition of nitrous oxide reductase by acetylene had no significant effect on alkalinization elicited by nitrate or nitrite. Several mutants negative by the phenol red staining test were generated by transposon Tn5 mutagenesis of Paracoccus denitrificans. All these mutants were defective in the activities of nitrite and nitric oxide reductases while the other denitrification activities were present at the wild-type level.
- Published
- 2002
- Full Text
- View/download PDF
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