Moncef Hamdoun

Notch signaling is involved in human articular chondrocytes de-differentiation during osteoarthritis.

Abstract Context: During osteoarthritis (OA), chondrocytes undergo de-differentiation, resulting in the acquisition of a fibroblast-like morphology, decreased expression of collagen type II (colII) and aggrecan, and increased expression of collagen type I (colI), metalloproteinase 13 (MMP13) and nitric oxide synthase (eNOS). Notch signaling plays a crucial role during embryogenesis. Several studies showed that Notch is expressed in adulthood. Objective: The aim of our study was to confirm the involvement of Notch signaling in human OA at in vitro and ex vivo levels. Materials and methods: Normal human articular chondrocytes were cultured during four passages either treated or not with a Notch inhibitor: DAPT. Human OA cartilage was cultured with DAPT for five days. Chondrocytes secreted markers and some Notch pathway components were analyzed using Western blotting and qPCR. Results: Passaging chondrocytes induced a decrease in the cartilage markers: colII and aggrecan. DAPT-treated chondrocytes and OA cartilage showed a significant increase in healthy cartilage markers. De-differentiation markers, colI, MMP13 and eNOS, were significantly reduced in DAPT-treated chondrocytes and OA cartilage. Notch1 expression was proportional to colI, MMP13 and eNOS expression and inversely proportional to colII and aggrecan expression in nontreated cultured chondrocytes. Notch ligand: Jagged1 increased in chondrocytes culture. DAPT treatment resulted in reduced Jagged1 expression. Notch target gene HES1 increased during chondrocyte culture and was reduced when treated with DAPT. Conclusion: Targeting Notch signaling during OA might lead to the restitution of the typical chondrocyte phenotype and even to chondrocyte redifferentiation during the pathology.

Unusual suicides with band saws: Two case reports and a literature review

Suicides or suicide attempts with power saws (band, circular or chain saws) are rather rare events and only a few case reports exist in the forensic literature. The use of a band saw, in particular, has been extremely rare in cases of suicide. We report two cases of suicide that occurred in the same suburban area, three years apart. In each case, the victim was a carpenter and had a history of psychiatric disorder and/or of prior suicide attempts. We summarize the findings of the death scene investigations, the pertinent autopsy findings, and also summarize the world literature pertaining to suicide committed with power saws.

La mort subite au cours d’une activité sportive en Tunisie : à propos d’une série autopsique de 32 cas

PURPOSE To develop profile of the victims and to study circumstances, causes of death and autopsy findings. METHODS Retrospective study of cases of sudden death in sport activity whose autopsy was performed in forensic department of Tunis, between January 2005 and December 2009. RESULTS During study period, 32 cases of SD in sport activity were recorded. These are amateur athletes predominantly male (84% of cases). Victims are aged between 15 and 79 years with an average age of about 33.16 years. Young subjects whose age is less than 35 years representing 68.7% of cases. 9.3% of victims had a family history of SD and 18.7% of cases had a known cardiac history. The sports most involved are running (40.6% of cases), football (31.3% of cases) and dance (12.5% of cases). Sixty-nine percent of victims died during sports activities. Presence of witnesses was noted in all cases; however, none of these witnesses has begun resuscitation. Cause of death was cardiac in 84.4% of cases. In young athletes, hypertrophic cardiomyopathy is the leading cause (nine cases), followed by arrhythmogenic right ventricular dysplasia (three cases). Among other causes, there is the myocardial bridge, congenital anomalies of the coronary arteries, aortic dissection and dilated cardiomyopathy. Beyond 35 years, coronary artery diseases represent the cause of death (nine cases). Only case of death secondary to non-cardiac disease occurred after a severe asthma attack. In four cases (12.5%), no cause of death was identified after a complete autopsy accompanied by further investigations. The cause of the death was imputed to a rhythmic pathology. CONCLUSION This is the first study dealing with autopsy in SD in sport have provided a specific profile of victims. Other studies on larger samples and using standardized autopsy protocols are needed.

Sudden Death Due to Hydatid Disease: A Six‐Year Study in the Northern Part of Tunisia

Human ecchinococcosis also known as hydatid disease is a zoonotic infection caused by the tapeworm Ecchinococcus with 2–3 Million cases worldwide. We hereby report a 6 years period study of Sudden death due to hydatidosis aiming to analyze the epidemiological criteria, death circumstances, and autopsy observations attributed to hydatid disease. During the past 6 years, 26 death cases were due to hydatid disease. Our analysis shows that the sex ratio (M/F) was 1.6, the mean age was 31‐year old, and 65% of the subjects lived in rural places. In 17 cases, death occurred in the victims place, five victims died after a heavy exercise, and in two cases, death occurred immediately after trauma. At autopsy, 91% of the cysts were found in the liver. In three cases, death followed a septic state, and in two cases, it followed an acute respiratory failure. Death was attributed to anaphylaxis in 17 cases.

Sex determination of a Tunisian population by CT scan analysis of the skull

It is widely accepted that the estimation of biological attributes in the human skeleton is more accurate when population-specific standards are applied. With the shortage of such data for contemporary North African populations, it is duly required to establish population-specific standards. We present here the first craniometric standards for sex determination of a contemporary Tunisian population. The aim of this study was to analyze the correlation between sex and metric parameters of the skull in this population using CT scan analysis and to generate proper reliable standards for sex determination of a complete or fragmented skull. The study sample comprised cranial multislice computed tomography scans of 510 individuals equally distributed by sex. ASIRTM software in a General ElectricTM workstation was used to position 37 landmarks along the volume-rendered images and the multiplanar slices, defining 27 inter-landmark distances. Frontal and parietal bone thickness was also measured for each case. The data were analyzed using basic descriptive statistics and logistic regression with cross-validation of classification results. All of the measurements were sexually dimorphic with male values being higher than female values. A nine-variable model achieved the maximum classification accuracy of 90% with −2.9% sex bias and a six-variable model yielded 85.9% sexing accuracy with −0.97% sex bias. We conclude that the skull is highly dimorphic and represents a reliable bone for sex determination in contemporary Tunisian individuals.

Pattern of suicide by self-poisoning in Northern Tunisia: An eleven-year study (2005-2015)

OBJECTIVE The aim of our study was to discuss the epidemiological features of self-poisoning suicide in Northern Tunisia. METHODS We conducted a retrospective, descriptive and cross-sectional study, including all the cases of fatal self-poisoning suicide occurring between January 2005 and December 2015. RESULTS In the study period, 204 cases of self-poisoning suicide occurred in northern Tunisia, with a prevalence of 0.44 cases/100 000 inhabitants/year. Among these cases, 59% were females (the sex ratio was 0.69). The mean age was 34 ± 15.3 years-old. The most common age group of the victims (28.4%) was between 20 and 29 years old. Victims were unemployed in 45% of cases and single at the time of suicide in 52%. None of the victims left a suicide note. Self-poisonings were due to the ingestion of drugs (52.5%), pesticides (42.6%), caustic products (5.5%) and Butane gas (1 case). CONCLUSIONS Fatal casualties of self-poisoning in Tunisia are frequently young, single, unemployed women. This pattern would allow planning of targeted preventive measures.

Accidental and occupational ligature strangulation in northern Tunisia: four-case study

BackgroundDeath by strangulation is a violent and frequent method of homicides. Strangulation is rarely accidental due to ligature which is caused by a wide variety of objects such as cords, ropes or clothing articles (scarves). It concerns mostly accidents at work, rarely road traffic accidents and domestic ones. We report four cases of occupational and accidental strangulation causing death.Case presentationIn our cases, the ligature link was a scarf or a towel. The link was caught on the belt of a tractor in two cases: on a drill pipe and on a combine harvester. Death occurred on site in three cases. The external examination has marked an asphyxia syndrome associated with a large strangulation mark. Furthermore, the autopsy findings have revealed large ecchymotic infiltrations of the neck muscles, a rupture of the trachea, and the oesophagus with a disjunction of cervical vertebra with a contusion of the spinal cord.ConclusionsThe ruptures of the trachea, oesophagus and cervical vertebra are not classic strangulation lesions but are explained by the brutality and violence of the traction exerted on the neck. We highlight the importance of preventive measures in this accidental type of deaths.

0201: Symptoms before sudden cardiac death (the northern Tunisian sudden cardiac-death registry)

Purpose Despite significant enhancements in resuscitation methodology, survival after sudden cardiac arrest remains low. Improved knowledge of warning signs and symptoms may help to detect victims for sudden death. Aim to study the warning symptoms prior to sudden cardiac death. Methods We prospectively collected epidemiological and autopsy data from victims of sudden cardiac death in northern Tunisia (3.6 million people) between October 2012 and September 2013. We included victims ?20 years old requiring a forensic autopsy. Data (risk factors, symptoms) were collected by assessment of the accounts of family members/relatives, witnesses, as well as medical records during this time period. The heart was weighed and then investigated by macroscopic examination looking for scars of myocardial infarction. The three main coronary arteries were macroscopically examined by transverse slices at 2-3-mm intervals along their lengths. Results Of the 542 sudden deaths within the study period, 372 males and 91 females were medico-legally autopsied. Mean age of victims was 50.9±15 years. Physical inactivity and smoking were the most common risk factors, accounting for 74.7% and 61.5%, respectively. A family history of sudden death was identified in 10.8% of victims. Most deaths occurred in a public place (39.3%) or at home (36.9%). Of the total deaths, 298 (64.4%) occurred while the individuals were relaxing, 52 (11.2%) while sleeping, 92 (19.9%) while dealing with an activity, and 21 (4.5%) under emotional stress. Syncope was the most frequent symptom occurring in 36.1%, chest pain in 18.6%, dyspnea in 8.6% and 10.1% had dizziness or fainting. The autopsic study showed that 231 deaths (49.9%) were due to coronary artery diseases. Eight percent of victims have consulted a doctor within the last 48 hours and 21% up to 1 month. Conclusions Warning symptoms prior to sudden cardiac death may occur longer before the death. Recognizing these precocious signs could have implications for prevention of this public health problem.