Mohamed Allouche

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.

Securing implantable cardiac medical devices: use of radio frequency energy harvesting

Implantable Medical Devices (IMDs) are surgically implanted into a human body to collect physiological data and perform medical therapeutic functions. They are increasingly being used to improve the quality of life of patients by treating chronic ailments such as cardiac arrhythmia, diabetes, and Parkinsons disease. Wireless IMDs have shown recently important security concerns. In particular, it has been stated that lethal attacks can be launched on these devices. In this paper, we propose a solution to secure IMDs against unauthorized access, battery depletion, and denial of service attacks. A Radio Frequency energy harvesting solution is used to design a powerless mutual authentication protocol. A technique for dynamic biometric keys extraction from electrocardiogram signals collected at both sides (the programmer and the IMD) is used, allowing to secure access to the IMD devices in regular and emergency situations.

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.

Digital Investigation of Security Attacks on Cardiac Implantable Medical Devices

A Cardiac Implantable Medical device (IMD) is a device, which is surgically implanted into a patient’s body, and wirelessly configured using an external pr ogrammer by prescribing physicians and doctors. A set of lethal attacks targeting these devices can be conducted due to the use of vulnerable wireless communication and security protocols, and the lack of security protection mechanisms deployed on IMDs. In this paper, we propose a system for postmortem analysis of lethal attack scenarios targeting cardiac IMDs. Such a system reconciles in the same framework conclusions derived by technical investigators and deductions generated by pathologists. An inference system integrating a library of medical rules is used to automatically infer potential medical scenarios that could have led to the death of a patient. A Model Checking based formal technique allowing the reconstruction of potential technical attack scenarios on the IMD, starting from the collected evidence, is also proposed. A correlation between the results obtained by the two techniques allows to prove whether a potential attack scenario is the source of the patient’s death.

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.

Security of implantable medical devices: limits, requirements, and proposals

Implantable medical devices (IMDs) are surgically implanted into a human body to collect physiological data and perform medical therapeutic functions. They are increasingly being used to improve the quality of life of patients by treating chronic ailments such as cardiac arrhythmia, diabetes, and Parkinsons disease. However, recent research has demonstrated the deficiency of wireless IMDs in enforcing security and privacy, and discussed the impact of these attacks on the patients safety and efficacy of medical treatments. This paper provides an overview of the main vulnerabilities of IMDs. It also reviews the recent research on IMD security and privacy, and discusses their advantages and limitations. In this paper, we also describe the main requirements for improving security of IMDs and identify and discuss a set of research challenges for designing the next generation of secure wireless IMDs. Copyright

Cardiac Implantable Medical Devices forensics: Postmortem analysis of lethal attacks scenarios

Abstract Cardiac Implantable Medical devices (IMD) are increasingly being used by patients to benefit from their therapeutic and life-saving functions. These medical devices are surgically implanted into patients bodies and wirelessly configured by prescribing physicians and healthcare professionals using external programmers. However, these devices are threatened by a set of lethal attacks, due to the use of vulnerable wireless communication and security protocols, and the lack of security protection mechanisms deployed on IMDs. In this paper, we propose a digital investigation system for the postmortem analysis of lethal attack scenarios on cardiac IMDs. After developing a set of techniques allowing the secure storage of digital evidence logs which track the executed sensitive events, we implement an in-depth security solution allowing the protection of cardiac IMDs. An inference system integrating a library of medical rules is proposed to automatically infer potential medical scenarios that caused the patients death, or that created heart-related emergency situations (through the occurrence of ventricular tachycardia for example). A Model Checking based formal technique to reconstruct potential technical attack scenarios on a cardiac IMD, starting from the collected evidence, is also proposed. The results obtained by the two proposed reasoning techniques (i.e., the inference system and the Model Checking based algorithm) are correlated to prove whether a potential attack scenario is responsible of the occurrence of heart-related emergency situations or the death of a patient. Based on the proposed techniques, we design a decision-support system that reconciles in the same framework the medical and technical investigation aspects.

Powerless security for Cardiac Implantable Medical Devices: Use of Wireless Identification and Sensing Platform

Abstract Implantable Medical Devices are therapeutic devices designed to be surgically implanted into the body of a patient to continuously monitor his/her physiological parameters and automatically execute the suitable therapeutic functions when a chronic disorder is detected. Because of their therapeutic and life-saving benefits, cardiac IMDs, such as Pacemakers and Cardiac Defibrillators, are increasingly being used by patients to treat cardiac arrhythmia. Using an external programmer, cardiac IMDs are wirelessly configured and diagnosed by healthcare professionals. Nevertheless, the use of wireless networks to remotely access to these medical devices has shown important security concerns. In particular, it has been stated that lethal attacks can be launched on these devices. In this paper, we propose a powerless security solution to protect cardiac IMDs against security threats. We firstly identify and classify the main security attacks threatening IMDs, then we extend the IMD architecture by introducing a Radio Frequency Identification (RFID) system. Thanks to the use of a Radio Frequency energy harvesting solution, we design a powerless mutual authentication protocol between the IMD and the programmer allowing the prevention against battery depletion attacks. We also implement a technique for the dynamic biometric keys extraction from electrocardiogram signals collected at both sides (the programmer and the IMD), allowing a secure generation and distribution of master keys between the IMD and the programmer. A discussion about the main properties offered by the proposed solution and a simulation is conducted to evaluate its efficiency in protecting cardiac IMDs.

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.