Photoacoustic Characterization of TiO2 Thin-Films Deposited on Silicon Substrate Using Neural Networks

In this paper, the possibility of determining the thermal, elastic and geometric characteristics of a thin TiO2 film deposited on a silicon substrate, with a thickness of 30 μm, in the frequency range of 20 to 20 kHz with neural networks were analysed. For this purpose, the geometric (thickness), thermal (thermal diffusivity, coefficient of linear expansion) and electronic parameters of substrates were known and constant in the two-layer model, while the following nano-layer thin-film parameters were changed: thickness, expansion and thermal diffusivity. Predictions of these three parameters of the thin-film were analysed separately with three neural networks. All of them together were joined by a fourth neural network. It was shown that the neural network, which analysed all three parameters at the same time, achieved the highest accuracy, so the use of networks that provide predictions for only one parameter is less reliable. The obtained results showed that the application of neural networks in determining the thermoelastic properties of a thin film on a supporting substrate enables the estimation of its characteristics with great accuracy

The significance of Goodpasture antigen in hereditary nephritis

INTRODUCTION: Two types of hereditary nephritis, nonprogressive and progressive, clinically present as asymptomatic haematuria, sometimes combined with proteinuria. At the onset, in both types, light microscopic changes are minimal, immunofluorescence findings are negative, and diagnosis can be made only upon electron microscopic findings that are considered to be specific. OBJECTIVE: The aim of this study was to determine the significance of Goodpasture antigen detection in diagnosis of progressive and nonprogressive hereditary nephritis in its early phase. METHOD: Analysis of renal biopsy specimens was done in patients with hereditary nephritis that were followed from 1990 to 2005. Progression of renal disease was examined in 14 patients with Alport's syndrome, 10 patients with thin basement membrane disease, and 6 patients with unclassified hereditary nephritis diagnosed. For all these cases, indirect immunofluorescence study with serum from a patient with high titer of Goodpasture autoantibodies that recognize the antigenic determinants in human glomerular and tubular basement membrane was performed. RESULTS: In 11 out of 14 cases diagnosed as Alport's syndrome, there was negative staining with Goodpasture serum, and in 3 additional cases with Alport's syndrome, expression of Goodpasture antigen in glomerular basement membrane and thin basement membrane was highly reduced. In all 10 patients with thin basement membrane disease, immunofluorescence showed intensive, bright linear staining with Goodpasture serum along glomerular and tubular basement membrane. In 2 out of 6 patients with unclassified hereditary nephritis, Goodpasture antigen expression was very strong, in one patient it was very reduced, and in 3 patients it was negative. CONCLUSION: The results of our study show that Goodpasture antigen detection plays a very important role in differential diagnosis of progressive and nonpregressive hereditary nephritis, particularly in early phases of the disease

The effect of the molecular properties of calcium channel blockers on their elimination route

Calcium channel blockers (CCBs) are among the most widely used drugs in cardiovascular medicine. In this study, nine CCBs (amlodipine, felodipine, isradipine, nicardipine, nifedipine, nimodipine, nisoldipine, verapamil and diltiazem) were investigated to assess the relationship between their molecular properties and elimination data obtained from literature. The descriptors of the molecular properties of CCBs were calculated using three software packages. The relationship between computed molecular properties and elimination data collected from relevant literature, initially investigated with simple linear regression analysis, showed poor correlation (R2 <0.25). Application of molecular weight or volume data as additional independent variable, multiple linear regression (MLR) revealed better correlations (R2 ~ 0.38) between CCB renal and fecal elimination data and their lipophilicity. Excluding nimodipine from the calculations resulted in more acceptable correlations. The best correlations were established after computed lipophilicity descriptor and molecular weight were applied (R2 = 0.66 with acceptable probability value). [Projekat Ministarstva nauke Republike Srbije, br. TR34031

The influence of certain molecular descriptors of fecal elimination of angiotensin II receptor antagonists

Angiotensin II receptor antagonists (ARBs) modulate the function of the renin-angiotensin-aldosterone system and are commonly prescribed antihypertensive drugs, especially in patients with renal failure. In this study, the relationship between several molecular properties of seven ARBs (candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, valsartan) and their fecal elimination data obtained from the literature were investigated. The ARB molecular descriptors were calculated using three software packages. Simple linear regression analysis showed the best 2 correlation between fecal elimination data and lipophilicity descriptor, ClogP values (R2 = 0.725). Multiple linear regression was applied to examine the correlation of ARBs’ fecal elimination data with their lipophilicity and one additional, calculated descriptor. The best correlation (R2 = 0.909 with an acceptable probability value, P <0.05) was established between the ARB fecal elimination data and their lipophilicity and aqueous solubility data. Applying computed molecular descriptors for evaluating drug elimination is of great importance in drug research

Could depression be a new branch of MIA syndrome?

The aims of the present study were to determine the prevalence of depression in our dialysis patients, to detect the most powerful variables associated with depression, and to determine the role of depression in prediction of mortality. The prospective follow-up study of 128 patients (77 HD and 51 CAPD, 65 male, aged 53.8 +/- 13.5 years, dialysis duration 64.7 +/- 64.8 months) was carried out over 3 6 months. Depression by the Beck Depression Inventory-BDI-II score, laboratory parameters (hemoglobin, serum albumin and creatinine concentration), immunological status (cytokines and hsCRP), comorbidity by Index of Physical Impairment (IPI) and adequacy of dialysis by Kt/V were monitored. The overall prevalence of depression in the dialysis patients (BDI score >= 14) was 45.3%, and 28.2%, respectively, for moderate and severe depression (BDI >= 20). The most powerful variable associated with depression was IL-6, but associations with albumin, hemoglobin, creatinine and IPI score were also found. During the follow-up period 36 patients died, 7 patients left the cohort and 2 patients were transplanted. If IPI score was not included in the multivariate Cox analysis, the BDI score remained one of the best predictors of mortality along with albumin. In conclusion, because of the close association of depression with inflammation, malnutrition, and cardiovascular mortality, it could be speculated that depression is one branch of the MIA (malnutrition, inflammation, atherosclerosis) syndrome

Effects of conventional versus biocompatible peritoneal dialysis solutions on peritoneal and systemic inflammation, malnutrition and atherosclerosis in CAPD patients

Background: Chronic inflammation, malnutrition and atherosclerosis (MIA syndrome) are important predictors of high mortality in continuous ambulatory peritoneal dialysis (CAPD) patients. We aimed to evaluate the effects of PD solutions (standard vs. biocompatible) on some parameters of MIA syndrome in patients undergoing CAPD. Methods: 42 stable patients who were on CAPD at least 2.5 years participated in this cross-sectional study. Patients who had severe anemia (Hb lt 10 g/l), immunomodulatory therapy, peritonitis or any inflammatory conditions for at least 3 months before the analysis, malignant disease and acute exacerbation of heart failure, were excluded. 21 (50%) patients were treated with standard PD solutions (CAPDP-1), while the remaining 21(50% of patients) were treated with biocompatible PD solutions (neutral solutions with lower level of glucose degradation products and lower concentration of calcium, CAPDP-2). All patients underwent echocardiography and B-mode ultrasonography of common carotid arteries together with assessments of nutrition status and parameters of systemic and local inflammation. Results: There were no significant differences between the groups concerning age, gender, underlying disease, residual renal function, peritoneal transport characteristics, comorbidity or therapy applied. Patients from group CAPDP-2 had a significantly lower serum level of hs-CRP (3.7 +/- 2.6 mg/l vs. 6.3 +/- 4.5 mg/l; p = 0.023) and significantly better nutritional status confirmed by mid-arm circumference (p = 0.015), mid-arm muscle circumference (p = 0.002) and subjective global assessment (14.28% of patients in CAPDP-2 vs. 71% of patients in CAPDP-1 were malnourished; p = 0.000). Group CAPD-2 had less frequent left ventricular hypertrophy (p = 0.039), thinner intima-media thickness (p = 0.005), smaller carotid narrowing (p = 0.000) and fewer calcified plaques of common carotide arteries (p = 0.003). No significant difference between the CAPDP groups was observed in serum and effluent levels of inflammatory cytokines (IL-1, IL-6 and TNF-alpha) and CA-125 effluent level. Logistic regression analysis did not confirm that biocompatibility of PD solutions was an independent predictor of any parameter of MIA syndrome. Conclusions: According to the present study and logistic regression analysis, the effect of biocompatible CAPD solutions on parameters of malnutrition, inflammation and atherosclerosis have to be confirmed by well-designed and controlled studies in a higher number of patients

Cholesterol Depletion Reduces Entry of Campylobacter jejuni Cytolethal Distending Toxin and Attenuates Intoxication of Host Cells ▿

Campylobacter jejuni is a common cause of pediatric diarrhea worldwide. Cytolethal distending toxin, produced by Campylobacter jejuni, is a putative virulence factor that induces cell cycle arrest and apoptosis in eukaryotic cells. Cellular cholesterol, a major component of lipid rafts, has a pivotal role in regulating signaling transduction and protein trafficking as well as pathogen internalization. In this study, we demonstrated that cell intoxication by Campylobacter jejuni cytolethal distending toxin is through the association of cytolethal distending toxin subunits and membrane cholesterol-rich microdomains. Cytolethal distending toxin subunits cofractionated with detergent-resistant membranes, while the distribution reduced upon the depletion of cholesterol, suggesting that cytolethal distending toxin subunits are associated with lipid rafts. The disruption of cholesterol using methyl-β-cyclodextrin not only reduced the binding activity of cytolethal distending toxin subunits on the cell membrane but also impaired their delivery and attenuated toxin-induced cell cycle arrest. Accordingly, cell intoxication by cytolethal distending toxin was restored by cholesterol replenishment. These findings suggest that membrane cholesterol plays a critical role in the Campylobacter jejuni cytolethal distending toxin-induced pathogenesis of host cells

Importance of immunological and inflammatory processes in the pathogenesis and therapy of Alzheimer's disease

The contribution of autoimmune processes or inflammatory components in the etiology and pathogenesis of Alzheimer's disease (AD) has been suspected for many years. The presence of antigen-presenting, HLA-DR-positive and other immunoregulatory cells, components of complement, inflammatory cytokines and acute phase reactants have been established in tissue of AD neuropathology. Although these data do not confirm the immune response as a primary cause of AD, they indicate involvement of immune processes at least as a secondary or tertiary reaction to the preexisting pathogen and point out its driving-force role in AD pathogenesis. These processes may contribute to systemic immune response. Thus, experimental and clinical studies indicate impairments in both humoral and cellular immunity in an animal model of AD as well as in AD patients. On the other hand, anti-inflammatory drugs applied for the treatment of some chronic inflammatory diseases have been shown to reduce risk of AD in these patients. Therefore, it seems that anti-inflammatory drugs and other substances which can control the activity of immunocompetent cells and the level of endogenous immune response can be valuable in the treatment of AD patients