Estimation of phase signal change in neuronal current MRI for evoke response of tactile detection with realistic somatosensory laminar network model

Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm³. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.     

Tobacco consumption,opium use,alcohol drinking and the risk of esophageal cancer in North Khorasan,Iran

Background: There are some unique epidemiological characteristics of esophageal cancer in Iran. The objective of this study was finding the association between tobacco, substance and alcohol using with the risk of esophageal cancer in North Khorasan, Iran.

Methods: This Case-Control study was carried out on 96 patients with esophageal cancer and 187 controls. Controls were matched to cases by age and sex. Data were collected through structured interview. Data were analyzed by using chi-square test, T-test and logistic regression, in Stata software version 12.

Results: Our findings show Hookah smoking [OR = 6.1(CI_95%:1.2–13.1)] and opium consumption [OR = 2.1(CI_95%:1.2–3.5)] were associated with esophageal cancer. Cigarette and pipe smoking, age of onset of smoking, duration of smoking, number of smoking per day, leaving history of smoking, years of leaving smoking, drug withdrawal, number of times of drug withdrawal, a history of drug relapse, alcohol consumption and alcohol dose–response were not related to esophageal cancer.

Conclusion: According to our results, hookah smoking and opium consumption enhance the risk of esophageal cancer in North Khorasan of Iran. We suggest appropriate planning to prevent the esophageal cancer in this district.     

Relationship between using cell phone and the risk of accident with motor vehicles: An analytical cross-sectional study

Purpose: Traffic accidents are one of the major health problems in the world, being the first cause of burden of illness and the second leading cause of death in Iran. The Sistan-Baluchestan province is one of the most accidental provinces of Iran with the highest rate of accidents-caused deaths. This study was conducted to determine the risk factors associated with traffic accidents in Zahedan through 2013 to 2016. Methods: This analytical cross-sectional study was carried out on 223 drivers from Zahedan who were traumatized by traffic accident and sent to Zahedan hospitals. The data were obtained through interviews taken by the trained interviewers via refereeing to the medical records and collected in the researcher-made checklist. Census was obtained from the study subjects. For data analysis, independent t-test, one-way ANOVA, Chi-square and logistic regression were used with the Stata software version 11.0. Results: In this study, 223 male subjects with the mean age of (32.54 ± 12.95) years, 39.8% single and 60.2% married, entered for investigation. Most accidents (38.8%) occurred between 12:00 to 17:59. While driving, 47.1% of the study subjects were using cell phones, 89.1% had manual use of mobile phones, 21.9% had a habit of sending short message service (SMS) and 23.4% had sent SMS within 10 min before the accident. The one way analysis of variance showed that the mean age of individuals with marital status, driving experience, education and accident with motorcycle were significantly different (p < 0.05). Also, the multivariate logistic regression test indicated a significant relationship of smoking, ethnicity, insurance and SMS typing while driving with motorcycle accident (p < 0.05). Conclusion: In this study, SMS and smoking while driving had the highest risk among the variables studied in the motorcycle accidents. Therefore, effective education attempting to enhance people''s awareness about the consequences of using cell phone and smoking during driving to reduce traffic accidents seems necessary.     

Treatment of horizontal root‐fractured maxillary incisors – a case report

Abstract – Traumatic dental injuries often occur to the teeth and their supporting tissues and they are the main reasons for emergency visit to a dental clinic. Management of a fracture depends on its position and the extent of root involvement. Horizontal root fractures are not seen frequently and the treatment consists of reduction and long‐term rigid fixation of the coronal segment. The present case demonstrates the successful management of two horizontally fractured maxillary central incisors with a follow‐up period of 9 months.     

Autotransplantation of splenic tissue

Autotransplantation of splenic fragments has already been carried out in humans. The optimal size of the particles and amount of tissue required for this procedure has yet to be found. In normal young pigs and miniature piglets, autologous splenic tissue was transplanted into the greater omentum. The regenerated splenic mass, splenic blood flow, and histology were studied six months later. Implanting small splenic particles produced comparable results to implanting thin slices of splenic tissue. The mass of regenerated splenic tissue was only 3.1 g after implanting the whole spleen and 4.5 g after transplanting half of the spleen, which means 5.3% and 7.8% respectively of the weight of control spleens. The blood flow per gram in the regenerated splenic tissue was much lower than in the normal spleen. The blood flow in the whole of the splenic tissue is important for the clearance function of the spleen. Six months after transplanting the whole or half of the spleen, the blood flow to the regenerated splenic tissue was only 1% of that in the control minipigs. When half of the spleen was left in situ, as a model for a partial splenectomy, and the other half transplanted, the regenerated mass was only 3.4% of all splenic tissue and the blood flow 1.5% of the total splenic blood flow. In this model the regenerated splenic mass was independent of the size of the implants and the mass of implanted tissue. The extremely low blood flow indicates an inadequate clearance function and thus the protective function would probably be negligible.