RESUMO
Titanium oxides are known to be appropriate hemocompatible materials which are suggested as coatings for blood-contacting devices. Little is known about the influence of nanometric crystal structure, layer thickness, and semiconducting characteristics of TiO2 on blood hemostasis. Having used sol-gel dip coating method in this study, TiO2 thin films were deposited on nano-scale electro-polished stainless steel 316L with 1 to 5 nanosized layers. Surface morphology and structure of the film were studied with X-ray diffraction and atomic force microscopy. Blood compatibility was also determined by measuring the platelet activation [CD62P expression], platelet adhesion [Scanning Electron Microscopy], and the blood clotting time on these samples. The films were compact and smooth and existed mainly in the form of anatase. By increasing the number of TiO2 thin layer, clotting time greatly extended, and the population of activated platelet and P-selectine expression changed according to the surface characteristics of each layer. The findings revealed that stainless steel 316L coated with nano-structured TiO2 layer improved blood compatibility, in terms of both blood platelet activity and coagulation cascade, which can decrease the thrombogenicity of blood contacting devices which were made from stainless steel
Assuntos
Aço Inoxidável , Nanoestruturas , Transição de Fase , Materiais BiocompatíveisRESUMO
This study investigated the expression and prognostic significance of the CD95 death receptor and CD20, a B cell-lineage associated marker, along with CD34 and CD44 non-lineage associated molecules in Iranian children with acute lymphoblastic leukemia [ALL]. We performed immunophenotyping for expressions of the molecules in blood samples from children diagnosed with ALL by using a panel of monoclonal antibodies for flow cytometry analysis. The expression of markers was evaluated in relation to clinical and paraclinical features as well as response to treatment in the patients. CD95 showed a higher expression in T-ALL compared to B-ALL [P<0.001]. Analysis of the clinical and laboratory findings at diagnosis in the group of B-ALL patients revealed an association between CD95 expression with lower white blood cell [WBC] numbers and bone marrow blasts [P<0.05]. We detected a positive correlation between the expressions of CD95 and CD44 [r=0.445, P<0.01] in B-ALL patients. There was an association between CD20 expression and several poor prognostic factors that included increased extramedullary involvement [EMI] and decreased platelet numbers [P<0.008]. The mean expression of CD34 in B-ALL was higher than T-ALL [P=0.004]. At follow-up, complete remission duration [CRD] and survival duration did not significantly differ between patients who were positive or negative for each marker. Association of the studied molecules with several prognostic factors implies the significance of CD95 molecule as favorable and CD20 as unfavorable prognostic markers for childhood ALL