Unsupervised white matter fiber clustering and tract probability map generation: applications of a Gaussian process framework for white matter fibers.

With the increasing importance of fiber tracking in diffusion tensor images for clinical needs, there has been a growing demand for an objective mathematical framework to perform quantitative analysis of white matter fiber bundles incorporating their underlying physical significance. This article presents such a novel mathematical framework that facilitates mathematical operations between tracts using an inner product between fibres. Such inner product operation, based on Gaussian processes, spans a metric space. This metric facilitates combination of fiber tracts, rendering operations like tract membership to a bundle or bundle similarity simple. Based on this framework, we have designed an automated unsupervised atlas-based clustering method that does not require manual initialization nor an a priori knowledge of the number of clusters. Quantitative analysis can now be performed on the clustered tract volumes across subjects, thereby avoiding the need for point parameterization of these fibers, or the use of medial or envelope representations as in previous work. Experiments on synthetic data demonstrate the mathematical operations. Subsequently, the applicability of the unsupervised clustering framework has been demonstrated on a 21-subject dataset.

Mathematical methods for diffusion MRI processing.

In this article, we review recent mathematical models and computational methods for the processing of diffusion Magnetic Resonance Images, including state-of-the-art reconstruction of diffusion models, cerebral white matter connectivity analysis, and segmentation techniques. We focus on Diffusion Tensor Images (DTI) and Q-Ball Images (QBI).

World PCBs map: storage and effects in man and his biologic environment in the 1970s.

PCB residues are found in biota all over the world. A biologic magnification of PCBs has been demonstrated in the food chain: plankton-fish-fish eating birds. A world map of the PCBs residues in biota and some of their biologic effects are given in this study. The biologic effects of PCBs are varied and may generally be explained by the induction or inhibition of the activity of a large number of enzymes, which upsets quantitatively, normal biochemical processes. Harm to reproduction, growth, development, defense systems, tissues, and organs appeared in susceptible organisms as a result of such changes or as a chain reaction to heterostases. The adverse health effects, observed in persons occupationally exposed and in those accidentally poisoned, point to the risk for the general population of an ever-increasing environmental pollution by PCBs. There is need for an integrated approach, consisting of epidemiologic studies on high risk groups in the general population and in persons occupationally exposed, as well as periodic assessment of PCB residues in man, his food, and feed supplies.

Survival rates of patients hospitalized in French burns units during 1985.

This survey analyses data from 17 French burn units with respect to age, severity of injury and survival of patients admitted to hospital during 1985. Of the 2398 patients treated, more than half were between 15 and 50 years old. About 90 per cent of the patients had burns covering less than 50 per cent of the body surface area. The overall mortality rate was 11.8 per cent. The LD50 for the 2398 patients was a burned surface area of approximately 60 per cent of the total body surface area. The LD50 for patients less than 30 years old was a burn covering just over 80 per cent of the total body surface. The survival rate as a function of the Baux index was also analysed.

Use of topically applied silver sulphadiazine plus cerium nitrate in major burns.

All patients hospitalized between May 1987 and June 1988 suffering from burns covering over 50 per cent of the body surface area were treated by topical application of a cream containing cerium nitrate (0.05 M) and silver sulphadiazine (0.03 M) (CN + SSD). Eleven patients were included in this series, with a mean age of 35 years (range 22-65), a mean total burn size of 78 per cent (range 50-96 per cent) and full skin thickness covering a mean of 48 per cent (range 10-91 per cent). Eight patients survived (73 per cent) (mean age 36 years; mean total burn surface 73 per cent; mean full skin thickness burn surface, 38 per cent). These results are far better than those obtained in our Unit where a survival rate of 34 per cent was obtained in a comparable series of patients treated before 1987. Sixty positive blood cultures were obtained, which included a large variety of organisms with a slight predominance of Staph. aureus, Candida albicans and Ps. aeruginosa. Wound cultures were positive in 72 per cent of swabs and showed a predominance of Ps. aeruginosa (59 per cent of all the strains isolated). Even if CN + SSD appears in this series not to be very efficient in preventing wound colonization and septic complications, it permitted a very high survival rate in the treated patients, taking into account the extreme severity of the injuries. This beneficial effect is probably the consequence of the protective action of the yellow-green eschar formed by CN + SSD.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences between burns in rural and in urban areas: implications for prevention.

This study aimed to identify typical features of burns in rural areas and to improve their prevention by comparing the characteristics of burnt patients and their burns in rural and urban areas. A cross-sectional survey was conducted in 19 of the 23 French burns units over one year, using a structured questionnaire. We analysed the resulting database. Of the 1422 patients, excluding 188 burnt in unclassified areas, 420 (34%) were burnt in rural areas. Burns were more frequent in rural than in urban areas. Occupational burns were more frequent in rural than in urban areas. The characteristics of patients and burns did not differ between the areas. Patients burnt during everyday activities were older and more frequently had predisposing factors in rural than in urban areas. Burns occurred outdoors more often in rural than in urban areas and were frequently due to flames or explosions or to the use of barbecues or open fires. The hands and perineum were burnt more frequently in rural than in urban areas. Rural burns were more severe than urban burns: they were deeper, involved a larger body surface area and caused more deaths. Preventive measures in rural areas should take into account occupation and everyday activities. They should be specifically adapted to the profiles of burnt patients.

A silver sulphadiazine-impregnated lipidocolloid wound dressing to treat second-degree burns.

OBJECTIVE: To evaluate the efficacy and tolerance of Urgotul SSD dressing (Laboratoires Urgo) in the treatment of second-degree burns. METHOD: This was a national multicentre phase III non-comparative open-label prospective study involving 10 burns units. The 41 subjects were non-immunosuppressed adults with second-degree thermal burn(s), which were clinically non-infected, less than 24 hours old, had a surface area less than 500 cm2 and warranted the local use of silver sulphadiazine. For four weeks, subjects were followed up weekly with a clinical assessment, bacteriological swabs and photographic recording. RESULTS: Of the 41 patients, 24 healed within a mean of 10.8 days and 13 had a skin graft on the study burn within a mean of 11.5 days. There were four premature study withdrawals. The total number of cumulative treatment days was 445, and 298 treatments were performed (including 257 dressing changes). Mean dressing wear time was 1.73 days. None of the subjects acquired a secondary infection. Researchers took 121 bacteriological samples, and wound colonisation with Staphylococcus aureus was found in only one patient. At follow-up nursing staff reported that dressing acceptability was good. CONCLUSION: Use of Urgotul SSD led to a good wound outcome--wounds healed or were grafted.

[Child victims of house fires in France. Mortality, morbidity, prevention]. / Enfants, victimes d'incendies d'habitations en France. Mortalité, morbidité, prévention.

Children injuries by house fires in France are the cause of a severe mortality (sixty deaths in average each year) and of a morbidity for the survival due to smoke toxicity (oxygen deprivation and inhalation of toxic gases--CO and HCN) and to thermal burns. Epidemiological studies show that young children (0 to 4) are specially concerned by this threat and that the deaths occurred more often in some part of France (Nord-Pas-de-Calais Region). A special strategy for this prevention should be applied in France, the same available in USA, Sweden and UK, including information on the behavior one should have with children: never leave them alone and escape with them as soon as possible out of the smoke. The usefulness of smoke detectors should be confirmed by French administration and recommended to the public, since they have had effective results in other countries.

European Psychiatric Association (EPA) guidance on post-graduate psychiatric training in Europe.

The European Union Free Movement Directive gives professionals the opportunity to work and live within the European Union, but does not give specific requirements regarding how the specialists in medicine have to be trained, with the exception of a required minimum of 4 years of education. Efforts have been undertaken to harmonize post-graduate training in psychiatry in Europe since the Treaty of Rome 1957, with the founding of the European Union of Medical Specialists (UEMS) and establishment of a charter outlining how psychiatrists should be trained. However, the different curricula for post-graduate training were only compared by surveys, never through a systematic review of the official national requirements. The published survey data still shows great differences between European countries and unlike other UEMS Boards, the Board of Psychiatry did not introduce a certification for specialists willing to practice in a foreign country within Europe. Such a European certification could help to keep a high qualification level for post-graduate training in psychiatry all over Europe. Moreover, it would make it easier for employers to assess the educational level of European psychiatrists applying for a job in their field.

DIFFEOMORPHIC POINT SET REGISTRATION USING NON-STATIONARY MIXTURE MODELS.

This paper investigates a diffeomorphic point-set registration based on non-stationary mixture models. The goal is to improve the non-linear registration of anatomical structures by representing each point as a general non-stationary kernel that provides information about the shape of that point. Our framework generalizes work done by others that use stationary models. We achieve this by integrating the shape at each point when calculating the point-set similarity and transforming it according to the calculated deformation. We also restrict the non-rigid transform to the space of symmetric diffeomorphisms. Our algorithm is validated in synthetic and human datasets in two different applications: fiber bundle and lung airways registration. Our results shows that non-stationary mixture models are superior to Gaussian mixture models and methods that do not take into account the shape of each point.

Human middle longitudinal fascicle: segregation and behavioral-clinical implications of two distinct fiber connections linking temporal pole and superior temporal gyrus with the angular gyrus or superior parietal lobule using multi-tensor tractography.

The middle longitudinal fascicle (MdLF) is a major fiber connection running principally between the superior temporal gyrus and the parietal lobe, neocortical regions of great biological and clinical interest. Although one of the most prominent cerebral association fiber tracts, it has only recently been discovered in humans. In this high angular resolution diffusion imaging (HARDI) MRI study, we delineated the two major fiber connections of the human MdLF, by examining morphology, topography, cortical connections, biophysical measures, volume and length in seventy-four brains. These two fiber connections course together through the dorsal temporal pole and the superior temporal gyrus maintaining a characteristic topographic relationship in the mediolateral and ventrodorsal dimensions. As these pathways course towards the parietal lobe, they split to form separate fiber pathways, one following a ventrolateral trajectory and connecting with the angular gyrus and the other following a dorsomedial route and connecting with the superior parietal lobule. Based on the functions of their cortical affiliations, we suggest that the superior temporal-angular connection of the MdLF, i.e., STG(MdLF)AG plays a role in language and attention, whereas the superior temporal-superior parietal connection of the MdLF, i.e., STG(MdLF)SPL is involved in visuospatial and integrative audiovisual functions. Furthermore, the MdLF may have clinical implications in neurodegenerative disorders such as primary progressive aphasia, frontotemporal dementia, posterior cortical atrophy, corticobulbar degeneration and Alzheimer's disease as well as attention-deficit/hyperactivity disorder and schizophrenia.