Remote EPID-based dosimetric auditing using DVH patient dose analysis

Objective.The aim of this work was to develop and validate a method for remote dosimetric auditing that enables dose-volume histogram parameter comparisons of measured and planned dose in the patient CT volume.Approach. The method is derived by adapting and combining a remote electronic portal imaging (EPID) based auditing method (Virtual Epid based Standard Phantom Audit-VESPA) and a method to estimate 3D in-patient dose distributions from planar dosimetric measurements. The method was tested with a series of error-induced plans including monitor unit and multileaf collimator (MLC) positioning errors. A pilot audit study was conducted with eleven radiotherapy centres. IMRT plans from two clinical trials, a post-prostatectomy (RAVES trial) plan and a head and neck (HPV trial) plan were utilized. Clinically relevant DVH parameters for the planned dose and estimated measured dose were compared.Main results. The method was found to reproduce the induced dose errors within 0.5% and was sensitive to MLC positioning errors as small as 0.5 mm. For the RAVES plan audit all DVH results except one were within 3% and for the HPV plan audit all DVH results were within 3% except three with a maximum difference of 3.2%.Significance. The results from the audit method produce clinically meaningful DVH metrics for the audited plan and could enable an improved understanding of a centre's radiotherapy quality.

Multimodal MRI cerebral correlates of verbal fluency switching and its impairment in women with depression

BACKGROUND

The search of biomarkers in the field of depression requires easy implementable tests that are biologically rooted. Qualitative analysis of verbal fluency tests (VFT) are good candidates, but its cerebral correlates are unknown.

METHODS

We collected qualitative semantic and phonemic VFT scores along with grey and white matter anatomical MRI of depressed (n = 26) and healthy controls (HC, n = 25) women. Qualitative VFT variables are the "clustering score" (i.e. the ability to produce words within subcategories) and the "switching score" (i.e. the ability to switch between clusters). The clustering and switching scores were automatically calculated using a data-driven approach. Brain measures were cortical thickness (CT) and fractional anisotropy (FA). We tested for associations between CT, FA and qualitative VFT variables within each group.

RESULTS

Patients had reduced switching VFT scores compared to HC. Thicker cortex was associated with better switching score in semantic VFT bilaterally in the frontal (superior, rostral middle and inferior gyri), parietal (inferior parietal lobule including the supramarginal gyri), temporal (transverse and fusiform gyri) and occipital (lingual gyri) lobes in the depressed group. Positive association between FA and the switching score in semantic VFT was retrieved in depressed patients within the corpus callosum, right inferior fronto-occipital fasciculus, right superior longitudinal fasciculus extending to the anterior thalamic radiation (all p < 0.05, corrected).

CONCLUSION

Together, these results suggest that automatic qualitative VFT scores are associated with brain anatomy and reinforce its potential use as a surrogate for depression cerebral bases.

Heat transfer at the step of a CANDU calandria during a severe accident

During the in-vessel stage of a severe accident in a CANDU 6 reactor, decay heat from a collapsed core would be rejected through the calandria walls into the surrounding water. At the step in the calandria wall, the subshell and annular plate meet at a right angle pointing into the calandria. The geometry at this joint could concentrate the exiting heat flux, potentially leading to calandria failure. Finite element analysis is used to study the heat transfer near the welded joint. Different weld profiles, boundary conditions, and decay heat characteristics are considered, and the local concentration of exiting heat flux is calculated.

Finite Element Model of a Melting Terminal Debris Bed in a CANDU Calandria

Melting of the terminal debris bed at the bottom of a Canada deuterium uranium (CANDU) 6 calandria vessel during a severe accident is studied using a three-dimensional transient finite element analysis. Settling of the debris is modeled, as are the effects of changing temperature and porosity on debris material properties. The time and magnitude of maximum heat rejection from the debris bed, and the maximum mass of molten debris, are calculated as functions of the accident timing. The results are compared with those from the modular accident analysis program (MAAP)-CANDU severe accident code.

Utilisabilité des jeux vidéo sérieux avec activités physiques et cognitives dans le vieillissement normal, la maladie d’Alzheimer et les maladies apparentées

La prise en charge non-pharmacologique de la maladie d’Alzheimer et des maladies apparentées (MA) représente un enjeu de santé majeur chez les personnes âgées . L’environnement Enrichi (EE), combinaison de stimulations cognitive, physique et d’engagement social en contexte émotionnel positif, apparaît comme une méthode efficace pour lutter contre la progression d’une MA . La principale difficulté est de proposer aux patients un EE adapté et motivant. Les serious games peuvent aider dans ce sens . Xtorp est un Serious exerGame (à activité physique, SeG) d’action/aventure développé pour KinectTM. Le joueur pilote un sous-marin (Fig. 1). Il doit devenir Amiral 5 étoiles en collectant de l’expérience au cours de batailles et missions. Dix patients (MA stade léger) et 8 témoins ont suivi un programme d’entrainement avec le jeu durant 1 mois, réparties en 12 séances. Les performances au jeu, les émotions perçues (PANAS) et l’intensité d’effort physique induite par le jeu ont été étudiées. Tous les participants ont terminé au moins une fois Xtorp. Les patients ont une capacité de jeu inférieure aux témoins (temps total de jeu et vitesse de progression patents : 420 minutes et 185 points d’expérience/minute, témoins : 489 minutes et 287 points d’expérience/minute). Les patients et les témoins n’ont quasiment ressenti que des émotions positives, légèrement plus fortes pour les témoins (PANAS positifs patients : 27/50, témoins, 36/50 ; PANAS négatifs patients : 12/50, témoins 11/50). Enfin, le jeu a été stimulant physiquement mais à un moindre degré chez les patients (fréquence cardiaque de réserve moyenne et pic par séance patients : 33 % et 53 %, témoins : 44 % et 62 %). En conclusion Xtorp est un EE utilisable, motivant qui permet de réaliser une activité physique potentiellement modérée chez des patients présentant des troubles cognitifs.

Application of the ecosystem service concept at a small-scale: The cases of coralligenous habitats in the North-western Mediterranean Sea

The understanding of ecosystem services is essential to support sustainable use and preservation of ecosystems. Coralligenous habitats, main contributors of the Mediterranean marine biodiversity, are yet understudied in term of services provided. This study presents an original small-scale approach to investigate the services provided by coralligenous habitats of a French study area consisting of two marine sites (Marseille and Port-Cros sites) in order to cover two contrasted anthropogenic pressure despite the small-scale. Our results are based on the opinions of 43 experts who ranked 15 services in terms of existence and level of importance for human well-being: supporting ecological functions were considered the most important, then provisioning and cultural services. Regulating services were considered uncertain due to a lack of knowledge. The small-scale approach highlighted a need for a referential frame to determine the existence of services (e.g. geographical and temporal scales, benefits and beneficiaries levels).

Sex ratio in dementia with Lewy bodies balanced between Alzheimer's disease and Parkinson's disease dementia: a cross-sectional study

Background

Gender distribution varies across neurodegenerative disorders, with, traditionally, a higher female frequency reported in Alzheimer’s disease (AD) and a higher male frequency in Parkinson’s disease (PD). Conflicting results on gender distribution are reported concerning dementia with Lewy bodies (DLB), usually considered as an intermediate disease between AD and PD. The aim of the present study was to investigate gender differences in DLB in French specialized memory settings using data from the French national database spanning from 2010 to 2015 and to compare sex ratio in DLB with that in AD, Parkinson’s disease dementia (PDD), and PD. Our hypothesis was that there is a balanced sex ratio in DLB, different from that found in AD and PD.

Methods

We conducted a repeated cross-sectional study. The study population comprised individuals with a DLB, AD, PDD, or PD diagnosis according to the International Classification of Diseases, Tenth Revision, in the French National Alzheimer Database between 2010 and 2015. Sex ratio and demographic data were compared using multinomial logistic regression and a Bayesian statistical model.

Results

From 2010 to 2015 in French specialized memory settings, sex ratios (female percent/male percent) were found as follows: 1.21 (54.7%/45.3%) for DLB (n = 10,309), 2.34 (70.1%/29.9%) for AD (n = 135,664), 0.76 (43.1%/56.9%) for PD (n = 8744), and 0.83 (45.4%/54.6%) for PDD (n = 3198). Significant differences were found between each group, but not between PDD and PD, which had a similar sex ratio.

Conclusions

This large-sample prevalence study confirms the balanced gender distribution in the DLB population compared with AD and PD-PDD. Gender distribution and general demographic characteristics differed between DLB and PDD. This is consistent with the hypothesis that DLB is a distinct disease with characteristics intermediate between AD and PD, as well as with the hypothesis that DLB could have at least partially distinct neuropathological correlates.

The Fate of Eyes with Anterior Chamber Intra-Ocular Lenses

A total of 143 anterior chamber (AC) intra-ocular lenses (IOL) of various designs were implanted in a five-year period and followed for 18 to 76 months. The lenses were inserted as a secondary implant after extracapsular cataract extraction (ECCE) complicated by vitrectomy, or after primary intra-capsular extraction. The complications (corneal edema, uveitis/glaucoma, extrusion/imbedding, cystoid macular edema), the final visual acuity and the need for removal of the IOL were analyzed. Only small differences were found between the different lenses but some association was found between complicated surgery (ECCE + vitrectomy) and a higher rate of complication, poorer visual outcome and more frequent need for IOL removal. Cystoid macular edema was encountered only in cases with complicated ECCE. A high percentage of other ocular pathologies was found among the cases, possibly implying that diseased eyes are more prone to surgical complications. An alternative to the AC-IOL in cases with a ruptured posterior capsule is the suture-supported posterior chamber IOL, but the flexible-loop AC-IOL may not yet be obsolete.

Tetranuclear and dinuclear phenoxido bridged copper complexes based on unsymmetrical thiosemicarbazone ligands

Dinuclear and tetranuclear copper(ii) complexes based on N,S ligand systems in the solid state and in solution are described.

Development and characterization of a fully flexible stimulation system based on embedded liquid metal channels

Neuronal stimulation systems design is highly impacted by the overall resolution and adaptability of the device to the targeted application and area to stimulate. In this study is proposed a novel design for neural micro-stimulation electrode presenting high resolution and adaptability to any targeted area via a high flexibility. The use of liquid metal micro-channels encapsulated into a polymer allowed micro-stimulation pads at the tip of the channels. It presented a high degree of patternability to match different possible applications, as well as flexibility and interesting mechanic properties to make it insertable and adaptable in soft tissues. The design, fabrication process, and study of the electrical and mechanical behavior and stability of the device are discussed. Conductive U-shaped micro-channels down to a total diameter of 110 μm could be produced.

Comparison of Kaposi Sarcoma Risk in Human Immunodeficiency Virus-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

BACKGROUND

We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.

METHODS

We included cohort data of human immunodeficiency virus (HIV)-positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).

RESULTS

We included 208140 patients from 57 countries. Over a period of 1066572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73-7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34-3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09-6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/µL with those whose counts were <50 cells/µL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI, .17-1.63) but reduced by ≥95% in other regions.

CONCLUSIONS

Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.

Assessing morphology and function of the semicircular duct system: introducing new in-situ visualization and software toolbox

The semicircular duct system is part of the sensory organ of balance and essential for navigation and spatial awareness in vertebrates. Its function in detecting head rotations has been modelled with increasing sophistication, but the biomechanics of actual semicircular duct systems has rarely been analyzed, foremost because the fragile membranous structures in the inner ear are hard to visualize undistorted and in full. Here we present a new, easy-to-apply and non-invasive method for three-dimensional in-situ visualization and quantification of the semicircular duct system, using X-ray micro tomography and tissue staining with phosphotungstic acid. Moreover, we introduce Ariadne, a software toolbox which provides comprehensive and improved morphological and functional analysis of any visualized duct system. We demonstrate the potential of these methods by presenting results for the duct system of humans, the squirrel monkey and the rhesus macaque, making comparisons with past results from neurophysiological, oculometric and biomechanical studies. Ariadne is freely available at http://www.earbank.org.

Strabismus developing after unilateral and bilateral cataract surgery in children

PurposeTo evaluate the prevalence and risk factors of strabismus in children undergoing surgery for unilateral or bilateral cataract with or without intraocular lens implantation.MethodsMedical records of pediatric patients were evaluated from 2000 to 2011. Children undergoing surgery for unilateral or bilateral cataract with at least 1 year of follow-up were included. Children with ocular trauma, prematurity, or co-existing systemic disorders were excluded. The following data were evaluated: strabismus pre- and post-operation; age at surgery; post-operative aphakia or pseudophakia; and visual acuity.ResultsNinety patients were included, 40% had unilateral and 60% had bilateral cataracts. Follow-up was on average 51 months (range: 12-130 months). Strabismus was found preoperatively in 34.4% children, and in 43.3% children at last follow-up. Strabismus developed in 46.2% of children who were orthotropic preoperatively, whereas 32.3% of children who had strabismus before surgery became orthotropic. Strabismus occurred after unilateral or bilateral cataract surgery in 63.9% and 29.6% children, respectively. At the last follow-up, strabismus was found in 46.7% of aphakic and 58.7% of pseudophakic children (P=0.283). Children who developed strabismus were generally operated at a younger age as compared with those without strabismus (mean of 25.9 vs 52.7 months, P<0.001). Final visual acuity was inversely correlated with prevalence of strabismus.ConclusionStrabismus is a frequent complication after cataract surgery in children. Risk factors include unilateral cases and young age at surgery. No correlation was found between prevalence of strabismus and use of intraocular lens. Strabismus was more common in children with poor final visual acuity.

Abstract P2-09-23: Factors associated with BRCA genetic testing intention and uptake among Orthodox Jewish women

Background: Ashkenazi Jews have a 1 in 40 prevalence of carrying a BRCA1/2 mutation, mainly due to 3 founder mutations. Prior literature suggests that population-based genetic testing among Ashkenazi Jews is cost-effective and may detect over 50% more mutation carriers than family history-based screening. Orthodox Jewish women are an understudied population with unique social, cultural, and religious factors that may influence BRCA genetic testing. The aim of our study was to examine factors associated with BRCA genetic testing intention/uptake among the Orthodox Jewish community.

Methods: A one-time online survey was distributed to Orthodox Jewish women by 3 shuls from Washington Heights, NY (53% response rate) and through additional referrals. The questionnaire obtained information regarding demographics, breast cancer risk factors, genetic testing knowledge, decision self-efficacy, perceived breast cancer risk, breast cancer worry, and religious and cultural factors affecting medical decision-making. The Tyrer-Cuzick model was used to calculate lifetime breast cancer risk and accurate risk perception was defined as within +/-10% of actual lifetime risk. Descriptive statistics and multivariable logistic regression models were used to identify independent predictors of genetic testing intention/uptake.

Results: Among 342 evaluable participants, median age was 26 years (range, 19-77); 92% were Ashkenazi and 8% Ashkenazi/Sephardi; 98% had a college education, including 47% with post-graduate degrees. Despite being highly educated, only 54% of women had adequate genetic testing knowledge. Median lifetime breast cancer risk was 16% (range, 2.3-60.9) and only 44% had accurate breast cancer risk perceptions. Although 48% had a family history of breast cancer and 16% had a relative that tested positive for BRCA1/2 mutation, only 5% had undergone BRCA testing while 48% had the intention of undergoing genetic testing. Higher lifetime breast cancer risk, high decision self-efficacy regarding genetic testing, overestimation of breast cancer risk, and increased breast cancer worry were associated with genetic testing intention/uptake. The most important factors in the decision to have BRCA testing were to help prevent dying of cancer (55%), to help prevent getting cancer (54%), and effect on children (40%).

Multivariable analysis of factors associated with BRCA genetic testing intention/uptake OR95% CIp-valueDecision Self-Efficacy (range, 0 [not confident] - 4 [very confident])1.41.02-1.980.038Actual Lifetime Breast Cancer Risk (range, 0 - 100%)1.11.03-1.100.0005Accuracy in Breast Cancer Risk Perception   Accurate (referent)1.0--Underestimate1.20.50-2.850.691Overestimate2.61.45-4.610.001Breast Cancer Worry (range, 1 [none] - 7 [worry all of the time])1.51.18-1.980.001

Conclusions: By understanding the religious and cultural issues regarding genetic testing in the Orthodox Jewish community, we can develop targeted interventions designed to enhance decision self-efficacy and improve accuracy of breast cancer risk perceptions to decrease unnecessary worry. This may in turn increase informed decision-making about BRCA genetic testing and implementation of cancer prevention strategies among Ashkenazi Jews.

Citation Format: Trivedi MS, Tang EY, Kukufka R, Chung WK, David R, Respler L, Leifer S, Schechter I, Crew KD. Factors associated with BRCA genetic testing intention and uptake among Orthodox Jewish women. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-23.

Increased expression of circulating miRNA-93 in women with polycystic ovary syndrome may represent a novel, non-invasive biomarker for diagnosis

MicroRNAs (miRNA) are a novel class of small noncoding single-stranded RNA molecules that regulate gene expression. There is increasing evidence of their importance in polycystic ovary syndrome (PCOS). The objective was to determine if miRNA-93 and miRNA-223 are differentially expressed in the circulation of women with PCOS compared to age matched women. A case-control study comparing women with PCOS (n = 25) to age and weight matched controls (n = 24) without PCOS was performed. MiRNA-93 and miRNA-223 were determined by total RNA reverse transcription. Both miRNA-93 and miRNA-223 were significantly increased relative to the control group (p < 0.01, p = 0.029 respectively). In both groups there was no correlation of either miRNA-93 or miRNA-223 with insulin, HOMA-IR, HOMA-β or testosterone levels. The area under the receiver operator characteristic curve for miR-223 and miR-93 was 0.66 and 0.72 respectively, suggesting miR-93 is a more efficient biomarker than miR-223 for diagnosis of PCOS. The combination of the two miRNAs together, tested using multiple logistic regression analysis, did not improve the diagnostic potential. In conclusion, circulating miRNA-93 and miRNA-223 were higher in women with PCOS compared to age and weight matched controls independent of insulin resistance and testosterone levels, and miR-93 may represent a novel diagnostic biomarker for PCOS.

L’apathie dans les maladies dégénératives : évaluation, physiopathologie et thérapeutique

L’apathie est un des syndromes psychocomportementaux les plus fréquents au cours de l’évolution des pathologies neurodégénératives, précédant souvent l’apparition des symptômes cognitifs, classiquement reliés pour le grand public à l’entrée dans la maladie d’Alzheimer. L’apathie appartient au cortège des symptômes dits « négatifs », car souvent peu démonstratifs, avec expressivité clinique pauvre. Cette présentation abordera tout d’abord la place des nouvelles technologies dans l’aide au diagnostic. Puis, seront présentées les principales données relatives à la physiopathologie de l’apathie dans les atteintes neurodégénératives. Enfin, les modalités préventives et thérapeutiques, certes encore pauvres, seront abordées.

Avoir du nez ! Intérêt de l’olfaction dans l’évaluation et la prise en charge des troubles cognitifs et comportementaux dans les pathologies neuropsychiatriques

Les déficits de l’olfaction sont de plus en plus mis en évidence dans les pathologies psychiatriques (troubles bipolaires) comme dans les pathologies neurologiques et dégénératives (maladie de Parkinson, maladie d’Alzheimer). Ils peuvent constituer un marqueur de vulnérabilité et de dépistage précoce pour certaines de ces pathologies, mais ils peuvent aussi constituer une alternative prometteuse dans la prise en charge non pharmacologique de certaines perturbations émotionnelles et comportementales (anxiété, dépression, troubles du sommeil…), ainsi que de certains déficits cognitifs et mnésiques dans le spectre des pathologies neuropsychiatriques. L’objectif de ce symposium est tout d’abord de présenter les bases neurobiologiques de l’olfaction et de ses déficits, puis d’aborder l’intérêt du dépistage précoce des déficits de l’olfaction dans les pathologies neuropsychiatriques ainsi que les modalités thérapeutiques de la stimulation sensorielle olfactive en lien avec le développement des nouvelles technologies de l’information et de la communication.

Un système interactif pour aider les sujets âgés à utiliser des jeux sérieux

Avec le vieillissement de la population, la maladie d’Alzheimer et les pathologies associées représentent un défi majeur de santé publique. Parallèlement, les nouvelles technologies de l’information et de la communication prennent une part de plus en plus importante dans notre vie quotidienne et peuvent être un support tant pour l’évaluation que pour une aide directe des usagers. Les serious games sont des applications informatiques, dont l’intention est de combiner, avec cohérence, à la fois des aspects sérieux (Serious) comme l’enseignement, l’apprentissage, la communication, la rééducation, avec des ressorts ludiques issus du jeu vidéo (Game). Dans le cadre du projet AZ@GAME [2] lauréat AAP e-santé no 1 des Investissements d’Avenir, des jeux sont en cours de développement avec pour objectif de stimuler les capacités cognitives et physiques du patient. Un des problèmes rencontrés concerne l’engagement des sujets à comprendre puis à pratiquer ces jeux. En effet, engagement et motivation diminuent quand le patient rencontre des problèmes d’utilisation. Nous présentons ici un système d’assistance automatisé basé sur la technologie Kinect. Trois groupes de patients (Plaintes mnésique : n = 10 ; âge moyen, 76,6 ; MCI : n = 10 âge moyen, 77,9 ; et maladie d’Alzheimer : n = 10 ; âge moyen, 79,9) ont participés à une séance d’entraînement utilisant un jeu pour stimuler l’attention concentration. Le jeu était proposé avec ou sans l’aide du système. Les résultats indiquent que tous les groupes ont eu de meilleures performances (score et temps de jeu) avec l’aide du système. Ce résultat est tout particulièrement important dans le groupe de patients Alzheimer (score > de 31 % et temps de réalisation < de 10 % avec le système). Compte tenu de ces résultats la prochaine étape aura pour objectif de proposer un système encore plus motivant à une population plus importante de patients.

Les nouvelles technologies en neuropsychiatrie : de l’évaluation à la stimulation

Les objets technologiques, dont les nouvelles technologies de l’information et de la communication (nTIC), ainsi que les jeux vidéo dits « sérieux » (serious games) envahissent notre quotidien depuis quelques années. Leur utilisation dans les disciplines médicales est actuellement en développement croissant, notamment dans le domaine des neurosciences et du vieillissement. L’objectif de ce symposium est de présenter, en premier lieu, les recommandations scientifiques actuelles sur l’utilisation des nTIC et des serious games dans la prise en charge du sujet âgé et des atteintes neuropsychiatriques pouvant être associées. Ensuite, seront présentées les méthodes, utilisant les nTIC et les serious games, permettant d’améliorer l’évaluation et le dépistage des troubles cognitifs et des symptômes thymiques et comportementaux, ainsi que les stratégies non pharmacologiques, utilisant ces outils technologiques, permettant la stimulation des performances cognitives et la prise en charge des perturbations thymiques.

Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling

We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1° × 1° spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources.

From "mechanical" to "neuropathic" back pain concept in FBSS patients. A systematic review based on factors leading to the chronification of pain (part C)

INTRODUCTION

Beyond initial lesions, any form of spinal (re)operation can cause direct potential aggression to the nervous system by contact with neural tissue or by imprinting a morphological change on the neural tissue. The potential consequences of nerve root injury affect both peripheral and axial dermatomal distribution. The hypothesis of a possible neuropathic aspect associated with the back pain component of failed back surgery syndrome (FBSS) therefore appears to be reasonable. Its pathophysiology remains unclear due to the permanent interplay between nociceptive and neuropathic pain components, resulting in the coexistence of physiological and pathological pain at the same anatomical site. This paper is designed to extensively review the fundamental mechanisms leading to chronification of pain and to suggest considering the emerging concept of "neuropathic back pain".

METHODS

Literature searches included an exhaustive review of 643 references and 74 book chapters updated by searching the major electronic databases from 1930 to August 2013.

RESULTS

Inflammatory and neuropathic back pain could be distinguished from pure nociceptive pain as a result of an increased activity and responsiveness of sensitized receptors at the peripheral nervous system and also as a consequence of increased afferent inflow to the central nervous system, moving to a new, more excitable "wind-up" state. This can be clinically translated to an amplified response to a moderate/intense stimulus (primary hyperalgesia) or an aversive sensation provoked by the activation of low-threshold mechanoreceptors through non-noxious stimuli, which defines allodynia. Activated non-neuronal cells including microglia have been found to be cellular intermediaries in mechanical allodynia. Major changes in the spinal cord are the loss of inhibitory mechanisms, resulting in an increased activity of interneurons or projection neurons and a structural reorganization of the central projection pattern. This abnormal excitability of sensory neurons is coupled to changes in the neurotransmitter phenotype, which could induce a resistance to conventional analgesic treatments.

CONCLUSION

A clear understanding of the factors leading to the chronification of back pain should help us to move to the choice of mechanism related pain treatments to improve outcomes in FBSS chronic condition.

Anatomy, physiology and neurobiology of the nociception: a focus on low back pain (part A)

INTRODUCTION

The treatment of Failed Back Surgery Syndrome (FBSS) remains a challenge for pain medicine due to the complexity in the interactions between [1] a residual mechanical pain after surgery and, [2] a progressive transition into chronic pain involving central nervous system plasticity and molecular reorganization. The aim of this paper is to provide a fundamental overview of the pain pathway supporting the nociceptive component of the back pain.

METHODS

Literature searches included an exhaustive review of 643 references and 74 book chapters updated by searching the major electronic databases from 1930 to August 2013.

RESULTS

Pain input is gathered by the peripheral fibre from the innervated tissue's environment and relayed by two contiguous central axons to the brain, via the spinal cord. At this level, it is possible to characterize physical pain and emotional pain. These are supported by two different pathways, encoding two dimensions of pain perception: In Neo-spino-thalamic pathway, the wide dynamic range neuron system is able to provide the information needed for mapping the "sensory-discriminative" dimension of pain. The second projection system (Paleo-spino-thalamic pathway) also involves the ventromedial thalamus but projects to the amygdala, the insula and the anterior cingulate cortex. These areas are associated with emotionality and affect.

CONCLUSION

The mechanical component of FBSS cannot be understood unless the functioning of the pain system is known. But ultimately, the highly variable nature of back pain expression among individuals would require a careful pathophysiological dissection of the potential generators of back pain to guide pain management strategies.

Pathophysiological characterisation of back pain generators in failed back surgery syndrome (part B)

INTRODUCTION

Low back surgery, including as many type of spine procedures as the multitude of failed back surgery syndrome (FBSS) etiologies, is not always the answer for patients with chronic low back pain. Paradoxically, although a patient is considered to present FBSS because he has already undergone spinal surgery, any new symptom in the back or deterioration of back pain must not be immediately attributed to FBSS, but could be related to another cause independently of the initial mechanical problem. The aim of this paper is to extensively review the potential back pain generators in FBSS patients and to discuss their respective roles and interactions in back pain pathophysiology.

METHODS

Literature searches included an exhaustive review of 643 references and 74 book chapters updated by searching the major electronic databases from 1930 to August 2013.

RESULTS

Nociceptive fibres innervating any of the back anatomical structures can all play a part in the pathogenesis of the low back pain component in FBSS. The main spinal pain generators are not only myofascial syndrome or muscle spasm but also the facets, the disc complex or a sagittal imbalance and should therefore be carefully reviewed. Only after these steps and appropriate imaging, would it be justified to irremediably diagnose the patient with a refractory chronic condition, requiring no further spine surgery and to propose "palliative" pain treatment options.

CONCLUSION

Clinical investigations of the low back pain component in FBSS patients should be based on meticulous dissection of all potential triggers that could be a source of the nociceptive pain characteristics and possibly amenable to further aetiological treatment. Clinicians should therefore refine pain management strategies to ensure that the chronic nature of the pain becomes the guiding principle for multidisciplinary assessment.