Sébastien Duband

Revisited Microanatomy of the Corneal Endothelial Periphery: New Evidence for Continuous Centripetal Migration of Endothelial Cells in Humans

The control of corneal transparency depends on the integrity of its endothelial monolayer, which is considered nonregenerative in adult humans. In pathological situations, endothelial cell (EC) loss, not offset by mitosis, can lead to irreversible corneal edema and blindness. However, the hypothesis of a slow, clinically insufficient regeneration starting from the corneal periphery remains debatable. The authors have re‐evaluated the microanatomy of the endothelium in order to identify structures likely to support this homeostasis model. Whole endothelia of 88 human corneas (not stored, and stored in organ culture) with mean donor age of 80 ± 12 years were analyzed using an original flat‐mounting technique. In 61% of corneas, cells located at the extreme periphery (last 200 μm of the endothelium) were organized in small clusters with two to three cell layers around Hassall‐Henle bodies. In 68% of corneas, peripheral ECs formed centripetal rows 830 ± 295 μm long, with Descemet membrane furrows visible by scanning electron microscopy. EC density was significantly higher in zones with cell rows. When immunostained, ECs in the extreme periphery exhibited lesser differentiation (ZO‐1, Actin, Na/K ATPase, CoxIV) than ECs in the center of the cornea but preferentially expressed stem cell markers (Nestin, Telomerase, and occasionally breast cancer resistance protein) and, in rare cases, the proliferation marker Ki67. Stored corneas had fewer cell clusters but more Ki67‐positive ECs. We identified a novel anatomic organization in the periphery of the human corneal endothelium, suggesting a continuous slow centripetal migration, throughout life, of ECs from specific niches. STEM CELLS2012;30:2523–2534

Lamina propria of the human vocal fold: histomorphometric study of collagen fibers

BackgroundSince the seminal work of M. Hirano, which defined the three-layered lamina propria of the human vocal fold, there has been confusion in the labeling of each layer. Recent studies described the composition of fibers and interstitial molecules within the lamina propria leading to various biomechanical properties. However, collagen fibers appear as the most important structure component.MethodsWe used an optical analysis and the picrosirius-polarization method to describe collagen fibers from six adult and two fetal human larynges fixed in formalin and frontally sectioned in the middle part of the vocal fold.ResultsThe deep layer of the lamina propria is the most densely organized band of collagen fibers penetrating the superficial muscle bundles of the vocal muscle. The mean thickness of this layer is about 36% of the lamina propria and shows a network of strongly birefringent fibers (collagen type I and III). The superficial layer of the lamina propria is a narrow band of collagen fibers immediately below the basement membrane of the epithelium. The mean thickness of this layer is about 13% of the lamina propria and shows strong birefringent fibers. The intermediate layer is the less densely organized band between the deep and superficial layers. The mean thickness of this layer is about 51% of the lamina propria and shows clear, green weakly birefringent fibers characterized as collagen type III. The fetal lamina propria contains only a monolayer distribution of loose collagen fibers between the epithelium and the vocal muscle.ConclusionThese results help describe the distribution of collagen fibers within the lamina propria of the human vocal fold and have implications to understand the cover-body theory of voice production both in the adult and newborn.

Ear bleeding: A sign not to be underestimated in cases of strangulation.

Otorrhagia is commonly associated with cranial trauma and diving accidents. In some forensic manuals, bleeding in the ears is anecdotally associated with strangulation. We report 2 cases of criminal strangulation with hemotympanum and otorrhagia, emphasizing the importance of this sign with strangulation. We present the proposed pathophysiology of the injuries and the value of otoscopic evaluation to complete the external examination in forensic cases suspicious for strangulation.

La précarité est plus fréquente chez les victimes de violences volontaires : intérêt du score EPICES

OBJECTIVES To evaluate social vulnerability of victims of interpersonal violence having consulted a service of forensic medicine with an individual index of social vulnerability. POPULATION AND METHODS The population of victims of interpersonal violence was composed of 275 subjects having consulted the service of forensic medicine of the CHU of Saint Etienne. The social data were collected by questionnaire. Social vulnerability was measured by an individual index (EPICES) calculated on the basis of 11 weighted questions related to material and social deprivation. This population was compared with a reference population; the reference population was people, aged more than 16, living in the Rhône-Alpes region and examined in 2005 in one of the Health examination Centres (HECs) of the French General Health Insurance System, that is 7553 men and 6002 women. The comparisons between the two populations were made after redressing the population of the HECs on various socio-demographic data of the Rhône-Alpes region. The relations between violence and the variables studied were measured by odds ratios adjusted on age and sex. RESULTS The population of the victims of violence is younger than the reference population (p<0.001). It is characterized by a lower level of education (p<0.001, 15% in the higher education level vs 23%) and the categories Employees and Manual workers are more frequent (p<0.001). The situation with respect to employment is also different between the two populations, unemployment rate is higher (OR=2.25) and the retired are fewer (OR=0.41). Subjects in social vulnerability are more frequent in the victims (57% vs 36%). All these differences persist after adjustment on age and sex. The context in which the aggression took place (family, public area or at work) varies significantly according to social vulnerability. On the other hand, the majority of the other medico-legal characteristics are not different according to the level of social vulnerability. CONCLUSION The population of the victims of interpersonal violence has a socio-economic profile different from the reference population. Social vulnerability is associated with interpersonal violence, in particular with violence in the public and family area.

[Social vulnerability is more frequent in victims of interpersonal violence: value of the EPICES score].

OBJECTIVES To evaluate social vulnerability of victims of interpersonal violence having consulted a service of forensic medicine with an individual index of social vulnerability. POPULATION AND METHODS The population of victims of interpersonal violence was composed of 275 subjects having consulted the service of forensic medicine of the CHU of Saint Etienne. The social data were collected by questionnaire. Social vulnerability was measured by an individual index (EPICES) calculated on the basis of 11 weighted questions related to material and social deprivation. This population was compared with a reference population; the reference population was people, aged more than 16, living in the Rhône-Alpes region and examined in 2005 in one of the Health examination Centres (HECs) of the French General Health Insurance System, that is 7553 men and 6002 women. The comparisons between the two populations were made after redressing the population of the HECs on various socio-demographic data of the Rhône-Alpes region. The relations between violence and the variables studied were measured by odds ratios adjusted on age and sex. RESULTS The population of the victims of violence is younger than the reference population (p<0.001). It is characterized by a lower level of education (p<0.001, 15% in the higher education level vs 23%) and the categories Employees and Manual workers are more frequent (p<0.001). The situation with respect to employment is also different between the two populations, unemployment rate is higher (OR=2.25) and the retired are fewer (OR=0.41). Subjects in social vulnerability are more frequent in the victims (57% vs 36%). All these differences persist after adjustment on age and sex. The context in which the aggression took place (family, public area or at work) varies significantly according to social vulnerability. On the other hand, the majority of the other medico-legal characteristics are not different according to the level of social vulnerability. CONCLUSION The population of the victims of interpersonal violence has a socio-economic profile different from the reference population. Social vulnerability is associated with interpersonal violence, in particular with violence in the public and family area.

Sudden death due to myocardial metastasis of lingual squamous cell carcinoma

Cardiac metastases are rare events encountered in pathological practice but with often dramatic fatal outcome. Among malignancies associated with cardiac involvement, we would like to draw the attention of clinicians about lingual squamous cell carcinoma by reporting a sudden cardiac death in a 57-year-old woman without prior symptom and considered in remission 1 month before her death. The forensic autopsy led to the diagnosis emphasizing its role in epidemiology and public health.

Laryngeal teflonoma identified by Fourier-transform infrared microspectroscopy after forensic autopsy: an interesting tool for foreign material identification in forensic cases.

Forensic pathologists are sometimes confronted with microscopic foreign bodies mixed in with soft tissues surrounding wounds and which are thus difficult to identify. This identification, however, could be primordial in investigating a crime and in determining the weapon used. A case of a fatal respiratory distress syndrome due to conjoining suicidal drug intoxication and laryngeal obstruction by a voluminous foreign body giant cell granuloma is presented. The classical histological examination showed exogenous particles in the vocal cord tumor with birefringent qualities. Their analysis with Fourier-Transform infrared (FTIR) spectrometry coupled with infrared microscope allows the determination of their chemical nature as polytetrafluoroethylene and to the diagnosis of teflonoma. This case report put the emphasis on the forensic interest of the FTIR imaging.

Macroscopic, histological and toxicological aspects of early Gammarus pulex scavenging.

Two cases of scavenging postmortem freshwater shrimps (Gammarus pulex) are presented. We report the two first illustrated observations of cutaneous postmortem injuries inflicted by a G. pulex population, a small freshwater crustacean, on two non putrefied drowning victims, and we describe their particular histological features and their potential in forensic investigations.

Study of endolaryngeal structures by videolaryngoscopy after hanging: A new approach to understanding the physiopathogenesis

PURPOSE To evaluate laryngoscopic findings in hanging cases and to compare them with magnetic resonance imaging (MRI) and forensic autopsy results. MATERIALS AND METHODS Postmortem nasolaryngofibroscopy and MRI of five people who died from hanging were performed. Three people who died from other causes than hanging were also examined with a flexible laryngofibroscope. The results were compared with injuries discovered during forensic autopsy. RESULTS In all five hanging cases, laryngofibroscopic investigation showed a vocal fold position in complete adduction confirmed by MRI. This position did not seem to be influenced by the intensity of the forces applied to neck or postmortem delay and cadaveric phenomena. The vocal cords of the three non-hanging deceased were found in the intermediate position. These findings could suggest that pressure applied to the cervical nervous and cartilaginous structures or their elongation during hanging could lead to closure of the glottis with vocal cord adduction maintained after death. CONCLUSION Laryngofibroscopic examination in hanging cases could be very useful in confirming the vital character of the hanging and understanding asphyxial phenomena in incomplete suspension without laryngeal crush.

Intérêts de l’autopsie hospitalière illustrés par la casuistique

PURPOSE Clinical autopsy rate have been declining since the 1950s, but it remains a useful investigation tool. METHODS AND RESULTS Through six examples of our experience, we underline its interest for clinical, didactic and public health purposes. CONCLUSIONS We try to understand the reasons for its decline and, as demonstrated, it can be attributed to a number of factors. These need to be addressed in order to reassert the status of the autopsy as an investigation and audit tool which is crucial to the future effectiveness of modern medicine.