Performance evaluation of FBP reconstruction in SPECT Imaging

Abstract Introduction: The purpose of this study was to define an optimal parameter for the tomographic reconstruction procedure in routine single photon emission tomography (SPECT) studies. In this study Hoffman Brain Phantom is modified in such a way that only software capability is evaluated. The phantom is composed of several independent slice that can be imaged individually (planar) or in 3-D composition (SPECT). Method and Materials: Planar image of the slices were imaged separately. The tomographic image was ..

Cognitive reactivity: cultural adaptation and psychometric testing of the Persian version of the Leiden Index of Depression Sensitivity Revised (LEIDS-R) in an Iranian sample

Cognitive reactivity (CR) to the experimental induction of sad mood has been found to predict relapse in recovered depressed patients. The Leiden Index of Depression Sensitivity Revised (LEIDS-R) is a self-report measure of CR. The aim of the present study was to establish the validity and reliability of the Persian version of the LEIDS-R. The participants were recovered depressed and non-depressed Iranian individuals (n = 833). The analyses included content validation, factor analysis, construct validity, and reliability testing. Preliminary construct validation analysis confirmed that factor analysis was appropriate for the Persian version of the LEIDS-R. Factor analysis displayed similar factor loadings to the original English version. The total internal consistency of the translated version, which was assessed using Cronbach’s alpha coefficient, was equal to 0.90. The test-retest reliability of the total score was equal to that of the test-retest conducted after a two-week interval at 0.94. Content validity, face validity, and construct validity, as well as reliability analysis were all found to be satisfactory for the Persian version of the LEIDS-R. The Persian version of the LEIDS-R appears to be valid and reliable for use in future studies, and has properties comparable to the original version and to that obtained in previous studies

What explains gender inequalities in HIV/AIDS prevalence in sub-Saharan Africa? Evidence from the demographic and health surveys

Abstract Background Women are disproportionally affected by human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa (SSA). The determinants of gender inequality in HIV/AIDS may vary across countries and require country-specific interventions to address them. This study aimed to identify the socio-demographic and behavioral characteristics underlying gender inequalities in HIV/AIDS in 21 SSA countries. Methods We applied an extension of the Blinder-Oaxaca decomposition approach to data from Demographic and Health Surveys and AIDS Indicator Surveys to quantify the differences in HIV/AIDS prevalence between women and men attributable to socio-demographic factors, sexual behaviours, and awareness of HIV/AIDS. We decomposed gender inequalities into two components: the percentage attributable to different levels of the risk factors between women and men (the “composition effect”) and the percentage attributable to risk factors having differential effects on HIV/AIDS prevalence in women and men (the “response effect”). Results Descriptive analyses showed that the difference between women and men in HIV/AIDS prevalence varied from a low of 0.68 % (P = 0.008) in Liberia to a high of 11.5 % (P < 0.001) in Swaziland. The decomposition analysis showed that 84 % (P < 0.001) and 92 % (P < 0.001) of the higher prevalence of HIV/AIDS among women in Uganda and Ghana, respectively, was explained by the different distributions of HIV/AIDS risk factors, particularly age at first sex between women and men. In the majority of countries, however, observed gender inequalities in HIV/AIDS were chiefly explained by differences in the responses to risk factors; the differential effects of age, marital status and occupation on prevalence of HIV/AIDS for women and men were among the significant contributors to this component. In Cameroon, Guinea, Malawi and Swaziland, a combination of the composition and response effects explained gender inequalities in HIV/AIDS prevalence. Conclusions The factors that explain gender inequality in HIV/AIDS in SSA vary by country, suggesting that country-specific interventions are needed. Unmeasured factors also contributed substantially to the difference in HIV/AIDS prevalence between women and men, highlighting the need for further study

Application of Artificial Neural Network in Predicting the Survival Rate of Gastric Cancer Patients

&quot;nBackground: The aim of this study was to predict the survival rate of Iranian gastric cancer patients using the Cox proportional hazard and artificial neural network models as well as comparing the ability of these approaches in predicting the survival of these patients.&quot;nMethods: In this historical cohort study, the data gathered from 436 registered gastric cancer patients who have had surgery between 2002 and 2007 at the Taleghani Hospital (a referral center for gastrointestinal cancers), Tehran, Iran, to predict the survival time using Cox proportional hazard and artificial neural network techniques. &quot;nResults: The estimated one-year, two-year, three-year, four-year and five-year survival rates of the patients were 77.9%, 53.1%, 40.8%, 32.0%, and 17.4%, respectively. The Cox regression analysis revealed that the age at diag-nosis, high-risk behaviors, extent of wall penetration, distant metastasis and tumor stage were significantly associated with the survival rate of the patients. The true prediction of neural network was 83.1%, and for Cox regression model, 75.0%.&quot;nConclusion: The present study shows that neural network model is a more powerful statistical tool in predicting the survival rate of the gastric cancer patients compared to Cox proportional hazard regression model. Therefore, this model recommended for the predicting the survival rate of these patients

Effect of Various Concentrations of Inhibitors on the Expression of Chemokine Ip-10/Mob-1

Introduction: Chemokines are low molecular weight proteins (8-17kDa) with the main role of immune cells recruitment to injured tissues. IP-10/Mob-1 is a CXC chemokine and different cell systems in response to external stimulation produce this chemokine. Various signaling pathways are used by cell and tissue systems to regulate production of proteins e.g. chemokines. Therefore we have investigated some of these pathways leading to production of IP-10/Mob-1 by primary cultured hepatocytes. Methods: In the present study, hepatocyts were isolated from male Sprague Dawley rats and cultured on Waymouth medium in presence and absence of different inhibitors such as SB203580, MG132, KN62 and Staurosporine for indicated time points. Supernatant medium of culture was centrifuged and proteins were isolated by SDS-PAGE and transferred to nitrocellulose membranes, then membranes were incubated with IP-10/Mob-1 antibody overnight and followed by incubation with secondary antibody and then IP-10/Mob-1 was detected by ECL. Results: We showed that the expression of IP-10/Mob-1 has been decreased in presence of Staurosporine (10 and 50μM), SB203580(50μM) MG132 (20μM) and KN62 (10 and 20μM) but did not change in absence or lower concentrations of these inhibitors. Conclusion: Hence, these in vitro data may aid to a better understanding of the pathways in chronic liver injuries and identify clinical studies that may aid in treatment or prevention of these conditions. Furthermore, there may be further potential to prevent changes to hepatocyte phenotype and allow isolation of hepatocytes with a greater physiological phenotype. Therefore it could be concluded that all of these pathways are used by hepatocytes regarding expression of IP-10/Mob-1

Gene cloning and expression analysis of Gro/KC by primary hepatocytes

Abstract Background and purpose: It is now well established that several environmental stresses lead to activation of p38 MAP kinase and JNK in various cell systems which is followed by chemokine producion. We investigated the expression of both CXC chemokines SDF-1a (ELR-) and Gro/KC (ELR+) in rat H4 hepatoma cells in response to heat shock, hyper-osmolarity and oxidative stresses. The pattern of expression of these chemokines by hepatoma cells in response to stress conditions was also studied.Materials and Methods: Hepatoma cells were maintained in MEM medium. Cells were subjected to different stresses [(H2O2 0.15% (w/v), manitol and NaCl (160 mM) and heat shock [(42 °C for 20 minutes)]. At the indicated time points, cells were harvested and RNA was extracted, purified and expression of the chemokines were analysed by RT-PCR. cDNA was separated by gel electrophoresis on a 1% (w/v) agarose gel and visualised on a UV transilluminator.Results: Results obtained in this report showed that there was detectable but low expression of chemokines in H4 hepatoma cells. Heat shock failed to induce expression of chemokines in H4 rat hepatoma cells. Hyper-osmolarity also has not stimulated Chemokines expression. In this study we have also shown that oxidative stress did not induce expression of chemokines. Overall, although detection is possible but regulatory responses were not observed in H4 hepatoma cells.Conclusion: Several known injurious conditions cause recruitment of macrophages, neutrophils and other immune cells to the liver. Immune cells are recruited to the hepatic vasculature following local liver injury and consequent chemokine production. Our results demonstrated that failure in production of these chemokines by Hepatoma cells may be a way to escape from immune surveillance