43 research outputs found
Uncertainties in the production and propagation of cosmic rays in the Milky Way
Abstract We discuss the main sources of uncertainties in the calculation of the positron and antiproton top of the atmosphere spectra using models including diffusion and convection or reacceleration. We show that, even including uncertainties, the models that include diffusion and convection are more consistent with existing measurements. The next generation experiments like PAMELA will help to reduce the uncertainties in the values of the main free parameters of the models, thus improving our knowledge of the origin and propagation of cosmic rays
Physiology and Pathology of Cytokine: Commercial Production and Medical Use
Cytokines are small, short-lived proteins secreted by many different cell types. As signaling molecules, cytokines provide communication between cells and play a crucial role in modulating innate and adaptive immune response. The family of cytokines includes interferons, interleukins, chemokines, mesenchymal growth factors, tumor necrosis factor family and adipokines. Interferons (IFNs) are a multigene family of inducible cytokines with antiviral, antiproliferative, and immunomodulatory function. Recombinant DNA technology can be useful in the production of human IFNs. This process includes fermentation, purification, and formation of the final product. Interleukins are classified in families based on sequence homology, receptor-binding properties, biological function, and cellular sources. TNF and IL-1 are considered to be key mediators of inflammatory response, while IL-6 plays a key role in the transition from acute to chronic inflammation. The inhibition of TNF includes administration of anti-TNF antibody and TNF receptor (TNFR). The reduction of IL-1 level can be achieved by the administration of anti-IL-1 antibody or IL-1 receptor antagonist (IL-1Ra), and the reduction of IL-6 level in the treatment of chronic inflammatory diseases can be achieved by the administration of anti-IL-6 antibody and anti-IL-6 receptor antibody. Recombinant cytokines and cytokine antagonists (antibodies and receptors) can be used in treating many different diseases
Primary percoutaneous coronary intervention on unprotected left main coronary artery with staged complex bifurcational treatment: A case report
We present the case of patient with ST elevation myocardial infarction in cardiogenic shock with primary percutaneous coronary intervention of Left anterior descending coronary artery and Left main coronary artery with staged complex procedure on Left anterior descending/Diagonal branch bifurcation in Culotte manner. This case shows that “the simpler, the better” approach of only infarct related artery revascularization may be applied in acute patients with cardiogenic shock and optimal clinical and hemodynamic response on revascularization and intra-aortic balloon pump. But, complete revascularization should be done in staged procedure and later, a control coronary angiography with intravascular ultrasound assistance is mandatory
Histamine Blood Concentration in Ischemic Heart Disease Patients
The aim of this study was to investigate histamine blood concentration in subjects suffering from different types of ischemic heart diseases during the period of eight days. Our results showed that the histamine blood level was associated with different types of ischemic heart diseases. The blood histamine level in all investigated patients was significantly higher when compared to control subjects (44.87 ± 1.09 ng mL−1), indicating the increase of histamine release in patients suffering from coronary diseases. In patients suffering from ACS-UA and ACS-STEMI, the second day peak of histamine level occurs (90.85 ± 6.34 ng mL−1 and 121.7 ± 6.34 ng mL−1, resp.) probably as the reperfusion event. Furthermore, our data suggest that histamine can be additional parameter of myocardial ischemia along with cardiac specific enzymes and may prove to be an excellent single prognostic marker for multitude of ischemic heart diseases
Fractional flow reserve of intermediate lesions on collateral donor coronary arteries after myocardial infarction
Fractional flow reserve (FFR) is the gold standard for the functional assessment of coronary arteries. The aim of this study was to evaluate the relation between angiography, QCA and FFR in borderline lesions on collateral donor coronary arteries. In addition, FFR is compared with the angiographic appearance of collaterals to infarction-related arteries and echocardiographically assessed viability of infarct related the LV wall. In 60 patients with previous IM and occluded IRA, functional assessment of borderline coronary stenosis (30-70% DS) on collaterals donor artery was performed. We have not found statistically significant differences in these parameters between groups with different angiographic appearances of collaterals and different viability of distal myocardium. However, we found higher FFR values in diabetic patients (p=0.018). Higher FFR values in diabetic patients reveal the negative effects of diabetes on collateral growth and myocardial viability
Fractional flow reserve in patients with intermediate values of Duke Treadmill Score and borderline coronary lesions
Despite the wide usage of exercise ECG tests and Duke Treadmill Score (DTS) in clinical practice, no comparison between this scoring system and Fractional Flow Reserve (FFR) has yet been made, particularly in cases of angiographically verified borderline lesions. Thirty patients with single coronary lesions and angiographically assessed borderline stenosis (between 30-70%) and previously calculated intermediate values of DTS between -10 to +4 were examined using FFR. Adequate specificity and sensitivity (0.769 and 0.556, respectively) were in a more narrow range of -0.5 to -10. Sex and age did not have an influence on the DTS values. There was a correlation between the values of FFR and age (r=0.395, p=0.031) and between angiographic assessment of stenosis and quantitative coronary angiography (QCA) (r=0.648, p<0.0001). In the study population, a decision on revascularization could not be based solely on angiographic or QCA assessment of the artery or on the values of DTS
Fractional Flow Reserve Method in Cardiac Catheterization Laboratory without Cardiosurgical Backup: Initial Experiences
Background: Coronary artery disease is the most common cause of death in a modern world. This dictates the development a network of Catheterization laboratories without cardiosurgical capabilities.Aim: We postulate that the most valuable tool in the decision process on myocardial revascularization is fractional flow reserve (FFR), especially when we deal with borderline coronary lesions.Material and Methods: A total of 72 patients with 94 intermediate coronary stenosis (30%-70% diameter reduction) were included in this study. We tested FFR and angiography based decision model on myocardial revascularization.Results: Â Mean FFR value on left anterior descending coronary artery (LAD) was lower than in others two arteries (p=0.017). FFR after percutaneous coronary intervention (PCI) was significantly better (p<0.0001). The decision for PCI predominates before FFR diagnostics, but after FFR the decision is quite opposite. There is a weak negative correlation between FFR and diameter of stenosis assessed by angiography (r= - 0.245 p=0.038) and positive correlation between diameter of stenosis assessed by angiography and by quantitative coronary angiography (QCA) (r=0.406 p<0.0005).Conclusion: Â Our results strongly suggest that FFR is necessary tool in centers without possibilities of heart team onsite consultation and that prevents numerous unnecessary PCI
Three-dimensional biomechanical model of benign paroxysmal positional vertigo in the semi-circular canal
Benigna paroksizmalna pozicijska vrtoglavica (BPPV) je najčešći poremećaj vestibularnog sustava koji uzrokuju bazofilne čestice u polukružnom kanalu. Trodimenzijski biomehanički model SCC je opisan s potpunom 3D interakcijom fluid-struktura, čestica, zidova, deformacije kupule i endolimfnog strujanja fluida. Prikazan je model SCC s parametarskim definiranim dimenzijama i trodimenzijskim 3D rekonstrukcijama određenog pacijenta. Korištene su pune Navier-Stokes jednadžbe s jednadžbama kontinuiteta opisuje tok fluida dok je Arbitrary-Lagrangian Eulerian (ALE) formulacija korištena za gibanje mreže. Korištena je interakcija fluid-struktura za spajanje tekućine s deformacijom kupule. Primijenjen je algoritam za praćenje čestica. Korištene su različite veličine i broj čestica sa svojom punom interakcijom između sebe, zida i deformacije kupule. Raspodjela brzina, smičnog naprezanja i sila od strane endolimfe je prikazana kao parametar za jedan SCC kao i za tri SCC od određenog pacijenta. Svi modeli se koriste u korelaciji s istim eksperimentalnim protokolima s pokretima glave i gibanjem očiju - nystagmus. Puna interakcija fluid-struktura, čestica otoconia, zidova, deformacije kupula i endolimfnog fluida u tri dimenzije dat će više detalja za razumijevanje patologije specifičnog pacijenta u standardnoj kliničkoj dijagnostici i proceduri terapije za BPPV.Benign Paroxysmal Positional Vertigo (BPPV) is one of the most common vestibular disorders occuring due to the presence of basophilic particles in the semicircular canals (SCC). Three-dimensional biomechanical model of the SCC is described with full 3D fluid-structure interaction of particles, wall, cupula deformation and endolymph fluid flow. The model of the SCC with parametric defined dimension and fully 3D three SCC from patient specific 3D reconstruction is presented. Navier-Stokes equations with continuity equations described fluid flow while Arbitrary-Lagrangian Eulerian (ALE) formulation is used for mesh motion. Fluid-structure interaction for fluid coupling with cupula deformation is used. Particle tracking algorithm has been used for particle motion. Different size and number of particles with their full interaction between themselves, wall and cupula deformation are used. Velocity distribution, shear stress and force from endolymph side are presented for parametric one SCC and patient specific three SCC. All the models are used for correlation with the same experimental protocols with head moving and nystagmus eye tracking. Full fluid-structure interaction of otoconia particles, wall, cupula deflection and endolymph flow in three-dimension give more details and understanding of the pathology of the specific patient in standard clinical diagnostic and therapy procedure for BPPV
Two different ischaemic heart entities with the same clinical presentation
In this article we report two patients with different ischaemic heart entities who had sustained chest pain and showed numerous abnormal electrocardiograms (ECGs). To our knowledge, this is a very important report for the differential diagnosis of acute coronary syndrome and hypertrophic cardiomyopathy, which may give almost identical clinical presentation, ECGs and laboratory findings, making coronarography necessary for final diagnosis