Knowledge Acquisition for Diagnosis of Skin Diseases as an Initial Platform for an Expert System

Background: The diagnosis of skin diseases, especially in patients suffering from more than one disease or having similar symptoms, is very complex and access to the knowledge of skin diseases makes the design of an expert system easier. This research aimed to design a knowledge base used for diagnosis of complex skin diseases, selected by experts. Methods: This applied developmental research was conducted in 2015. The study population included 10 dermatologists of Razi Hospital, affiliated to Tehran University of Medical Sciences. Data collection was conducted through a questionnaire and a checklist. The questionnaire had face and content validity and was based on Likert scale according to the twelfth chapter of the International Classification of Diseases (Tenth revision). The questionnaires were administered to participants and collected after completion. A checklist of knowledge acquisition was designed for each disease based on the semiology book of skin diseases with “agree-disagree” options and completed by interviews. Signs and symptoms had an agreement with at least 70% of the experts, and symptoms that were added according to the experts’ proposal entered the checklist and was given to experts for consensus in future evaluations. The software used in this research was Clementine and its statistical method used was Stata. The data were analyzed using SPSS, 16. Results: The diseases including pemphigus vulgaris, lichen planus, basal cell carcinoma, melanoma, and scabies were selected to design the expert system. Confirmed signs and symptoms of the diseases selected by the experts included 106 causes. Conclusion: The choice of the selected diseases needed by specialists in the knowledge system is a very vital component needed in designing the expert knowledge base system to meet international standards based on international classification and according to the needs of specialists

Three dimensional film dosimetry of photon beam in small field sizes and beyond the heterogeneous regions using a GAFchromic films array

Introduction: Inaccurate dose prediction by treatment planning system (TPS) beyond the heterogeneous regions has been a great challenge in radiotherapy, particularly when small field sizes are used. Better understanding of this inaccuracy that depends on dosimetry methods is very crucial. Recently, the film stack dosimeter has been purposed for 3D comprehensive dosimetry. This study proposes an approach to investigate the accuracy of TPS for predicting dose distribution in small field sizes in the presence of nasopharynx heterogeneities by 3D stack film. Material & methods: The dose distribution and dose profile of rectangular heterogeneous nasopharynx (RHN) phantom with two air cavities and bone equivalent were measured with a 3D stack film dosimeter containing 9 GAFchromic-EBT2 films positioned beyond the heterogeneity regions. The film was validated using MCNPX-Monte Carlo (MC) simulation. The evaluation of TPS inaccuracy in small field sizes (3 � 3, 4 � 4, 5 � 5 cm2) was determined by comparing reconstructed 3D dose distribution of stack film dosimeter with TPS based on full scatter convolution (FSC) using in-house Matlab code. Results: The film measurements had a good agreement with the MC calculation for small fields in RHN phantom. The results showed a large discrepancy between stack film measurements and TPS calculations in the volumes enclosed high isodoses, so that the biggest difference occurred in 3 � 3 cm2 field size (relative mean difference = 1.72 ± 0.24, 1.5 ± 0.16 and P-value = 0.002, 0.001 for V95 and V90 respectively) and it decreased in 5 � 5 cm2 field size (relative mean difference = 0.46 ± 0.05, 0.35 ± 0.04 and P-value = 0.001, 0.002 for V95 and V90 respectively). Conclusion: The results suggested that 3D stack film dosimetry can be successfully used as a reliable dosimeter for QA procedure of heterogeneous region in small field sizes. Comparison of the measured and calculated dose volumes demonstrated that the TPS based FSC algorithm has a notable inaccuracy in estimation of dose distribution beyond the nasopharynx heterogeneities. Therefore: it seems heterogeneity corrections should be considered for nasopharynx treatment. © 2019 Elsevier Lt

Deficiency of Interleukin-2 Production and Interleukin-2 Receptor Expression on Peripheral Blood Leukocytes after Phytohemagglutinin Stimulation in Pemphigus

Peripheral blood mononuclear cells from 22 pemphigus patients with active disease and 30 normal subjects were evaluated for interleukin 2 (IL-2) production and IL-2 receptor expression following stimulation with phytohemagglutinin P (PHA-P). The IL-2 levels were lower in patients compared to corresponding controls and the production was delayed after PHA stimulation. This deficiency was most pronounced in severely affected patients. IL-2 receptor appearance also was lower after PHA stimulation in a small number of patients tested. These results indicate that some cellular immune functions are altered in pemphigus

Histological Study of Toxic Effects of Solder Fumes on Thickness of Germinal Epithelium in Seminiferous Tubule in Rat

Background: Toxic fumes generating during soldering contains various contaminants. The aim of the study was to determine toxic effects of solder fumes in thickness of semniferous tubule in Rat. Materials and Methods 48 male adult rats were randomly divided into experimental (n=30) and control (n=18) groups. Based on exposure time, each group was further divided into three subgroups such as 2, 4 and 6 weeks. The concentrations of toxic fumes were measured by standard method. Rats of experimental group were exposed to solder fumes for 1 hour/day. According to time table rats of experimental and control subgroups were killed. After fixation of testis, paraffin sections were stained by Hematoxylin & Eosin. The thicknesses of germinal epithelium were measured and data were analyzed by SPSS software version 17 with Mann Whitney test. Results: The results showed that the concentration of fumes was 0.193 mg/m3 for formaldehyde, 0.35 mg/m3 for Stanum (Sn) and 3 mg/m3 for Pb. Although there was no significant difference for weight of rats&rsquo; testis between control and experimental subgroups, there was only a significant difference for the thickness of germinal epithelium between 6 week experimental and control subgroups ( p<0.02). Conclusion: The results of study showed that solder fumes can change the structure and thickness of seminiferous epithelium in experimental groups in a time dependent manner