Clinical and biochemical responses after Gamma Knife surgery for a dopamine-secreting paraganglioma: case report.

The efficacy of Gamma Knife surgery (GKS) in local tumor control of non-secreting paragangliomas (PGLs) has been fully described by previous studies. However, with regard to secreting PGL, only one previous case report exists advocating its efficacy at a biological level. The aims of this study were: 1) to evaluate the safety/efficacy of GKS in a dopamine-secreting PGL; 2) to investigate whether the biological concentrations of free methoxytyramine could be used as a marker of treatment efficacy during the follow-up. We describe the case of a 62-year-old man diagnosed with left PGL. He initially underwent complete surgical excision. Thirty months after, he developed recurrent biological and neuroradiological disease; the most sensitive biomarker for monitoring the disease, concentration of plasma free methoxytyramine, started to increase. GKS was performed at a maximal marginal dose of 16 Gy. During the following 30 months, concentration of free methoxytyramine gradually decreased from 0.14 nmol/l (2*URL) before GKS to 0.09 nmol/l, 6 months after GKS and 0.07 nmol/l at the last follow-up after GKS (1.1*URL), confirming the efficacy of the treatment. Additionally, at 30 months there was approximately 36.6% shrinkage from the initial target volume. The GKS treatment was safe and effective, this being confirmed clinically, neuroradiologically and biologically. The case illustrates the importance of laboratory tests taking into account methoxytyramine when analyzing biological samples to assess the biochemical activity of a PGL. In addition, the identification of methoxytyramine as a unique positive biomarker could designate it for the monitoring of tumor relapse after treatments, including Gamma Knife surgery.

Traité complet de l'anatomie, de la physiologie et de la pathologie du système nerveux cérébro-spinal

Comprend : Atlas

Preoperative education and its influence on perception of recovery for clients awaiting total hip and total knee replacement surgery /

The puqjose of this study was to examine the manner in which an inviting approach to a preoperative teaching and learning educational experience influenced the perception and subsequent recovery of clients who were awaiting total hip and total knee replacement surgery. An in-depth review of the internal and external factors that shape client perceptions was undertaken in this study. In addition, this study also explored whether or not the Prehab Program was preparing clients physically, socially, and psychologically for surgery. Data for this qualitative case study research were collected through preoperative interviews with 4 participants awaiting total hip replacement surgery and 1 participant awaiting total knee replacement surgery. Four postoperative interviews were conducted with the participants who had received total hip replacement surgery. The occupational therapist and physical therapist who were the coleaders of the Prehab Program at the time of this study were also interviewed. The results of this study suggest that while individuals may receive similar educational experiences, their perceptions of the manner in which they benefited from these experiences varied. This is illustrated in the research findings, which concluded that while clients benefited physically from the inviting approach used during the practical teaching session, not all clients perceived the psychological benefits of this practice session, especially clients with preexisting high levels of anxiety. In addition to increasing the understanding of the internal as well as external factors that influence the perceptions of clients, this study has also served as an opportunity for reflection on practice for the Prehab therapists and other healthcare educators.

The validation of heart rate variability in individuals with spinal cord injury

The current classification system for spinal cord injury (SCI) considers only somatic information and neglects autonomic damage after injiuy. Heart rate variability (HRV) has the potential to be a valuable measure of cardiac autonomic control after (SCI). Five individuals with tetraplegia and four able-bodied controls underwent 1 min continuous ECG recordings during rest, after Metoprolol administration (max dose=3x5mg) and after Atropine administration (0.02mg/kg) in both supine and 40° head-up tilt. After Metoprolol administration there was a 61.8% decrease in the LF:HF ratio in the SCI participants suggesting that the LF:HF ratio is a reflection of cardiac sympathetic outflow. After Atropine administration there was a 99.1% decrease in the HF power in the SCI participants suggesting that HF power is highly representative of cardiac parasympathetic outflow. There were no significant differences between the SCI and able-bodied participants. Thus, HRV measures are a valid index of cardiac autonomic control after SCI.

A possible role for chemokine signalling through CXCR4 as a downstream effector of retinoic acid signalling in the regenerating tail and spinal cord of Notophthalmus viridescens

The newt, Notopthalmus viridescens is one of the few tet rapod vertebrates capable of extensive regeneration of the central nervous system, however, the factors involved in this process are still unknown. Chemokine signalling through the receptor CXCR4, has been found to be involved in the development of the central nervous system of mammals and more recently in epimorphic fin regeneration in zebrafish. We have hypothesized that the CXCR4 signalling pathway is involved in spinal cord and tail regeneration in the adul t newt , possibly as a downstream target of retinoic acid signalling. We found that CXCR4 mRNA expression was observed in the brain, spinal cord, heart, gut, liver and regenerating tail blastemas. CXCR4 expression increased over the f i rst 12 days of tail regeneration and returned to basal expression levels at day 21 of regeneration. Inhibition of CXCR4 wi th AMD3100, a specific receptor antagonist, led to a decrease in CXCR4 mRNA in the regenerating tail 14 days post amputation. Histological analysis suggests a delay in the early stages of tail and spinal cord regeneration. Spinal cord explants t reated wi th CXCL12, the ligand to CXCR4, displayed enhanced neurite outgrowth in vitro. Explants t reated wi th AMD3100 abolished any retinoic acid enhanced neurite outgrowth effects suggesting a link between these signalling pathways.

The Effect of Functional Electrically Stimulated Ambulation Training on Locomotor Function and Quality of Life in Individuals With Incomplete Spinal Cord Injury

The purpose of this study was to investigate the effects of a 12-week FES-ambulation program on locomotor function and quality of life after incomplete spinal cord injury. Six individuals with incomplete SCI participated in the study. Over-ground walking endurance (6MWT), speed (10MWT), independence (WISCI II) and body-weight support were assessed. Quality of life was assessed via the SF-36, WHOQOL-BREF, Perceived Stress Scale, Center of Epidemiological Studies for Depression scale, and task self-efficacy. Participants experienced significant improvements in walking endurance (223.6±141.5m to 297.3±164.5m; p=0.03), body-weight support (55.3±12.6% to 14.7±23.2%; p= 0.005) and four of the six participants showed improvements on the WISCI II scale (1-4 points). In addition, there was a significant reduction in reported bodily pain (6.5±1.2 to 5.0±1.7; p=0.04). Therefore, FES-ambulation is an effective means for enhancing over-ground locomotor function in individuals with incomplete SCI. It may also be an effective method for reducing pain in individuals with SCI.

Utilizing a Phenomenological Approach to Examine the Experience of Sexuality for Women Concerned about Urinary Incontinence following Spinal Cord Injury

Sexuality after spinal cord injury (SCI) is a complex issue that is influenced by a number of social, psychological and physiological factors, one of which is urinary incontinence (UI). Using a phenomenological approach, seven mixed methods interviews combining both the interview guide and standardized open-ended approaches were conducted to examine the experience of sexuality for women who are concerned about UI following SCI. Sexual function was one of the top priorities for the women after SCI, and UI was one of the main concerns the women had regarding sexuality. The findings of this study demonstrate that various dimensions of intimacy and the sexual experience as a whole were affected by UI, and the women discussed both physical and psychological concerns. The main issues regarding sexuality included concerns related to relationships, frustrations with limited sexual activities and the difficulty of being sexually satisfied, the number of unanswered questions and concerns, and a fear of being hurt or injured while participating in sexual activities. The main concerns regarding UI were embarrassment, the work and inconvenience involved with the clean-up of UI, bladder infections, the lack of accessible washrooms, and the negative effects of UI medications. When examining sexuality and UI together, the major issues were the constant comparison to the way things were before SCI, as well as the new concerns that the women did not have to worry about previously, worrying about how their partner would react if UI were to occur during sexual activity, and the impact of their own feelings toward UI on sexuality, a connection between pleasurable sexual sensations and UI as well as difficulty differentiating between the sensation of UI with the sensation of UI, dealing with infected urine during sexual activity, having to discuss UI with a new potential sexual partner, and a fear of rejection. Other identified issues included those related to body image, a lack of resources, Doctors who were inadequately educated regarding SCI, and issues related to both having and raising children. There is a significant shortage of information available for women with SCI to use as a resource regarding sexual function in general, and sexual function as it relates to UI. It is necessary that future work focus on creating resources to assist in this area, and that the dissemination of those resources becomes both appropriate and effective. Addressing sexual function and UI which are among the top concerns for this population has the opportunity to greatly improve quality of life (QOL) for these individuals.

Dietary Strategies to Optimize Wound Healing after Periodontal and Dental Implant Surgery: An Evidence-Based Review

Methods to optimize healing through dietary strategies present an attractive option for patients, such that healing from delicate oral surgeries occurs as optimally as possible with minimal patient-meditated complications through improper food choices. This review discusses findings from studies that have investigated the role of diet, either whole foods or individual dietary components, on periodontal health and their potential role in wound healing after periodontal surgery. To date, research in this area has largely focused on foods or individual dietary components that may attenuate inflammation or oxidant stress, or foster de novo bone formation. These studies suggest that a wide variety of dietary components, including macronutrients and micronutrients, are integral for optimal periodontal health and have the potential to accelerate oral wound healing after periodontal procedures. Moreover, this review provides guidance regarding dietary considerations that may help a patient achieve the best possible outcome after a periodontal procedure.

Exploring Body-Related Experiences among Individuals with Spinal Cord Injury

Using modified constructivist grounded theory, the purpose of the present study was to explore body-related experiences, specifically body image, in people with spinal cord injury. A total of nine participants (five women, four men) who had a broad range of body image experiences (from very negative to very positive) were interviewed. Most participants explained experiencing a fluctuating body image that varied from day-to-day. Negative body image experiences were represented by appearance, weight concerns, and function with all body image experiences encompassed by self-presentational concerns and tactics (an unanticipated finding). Positive body image was represented by acceptance, appreciation and gratitude of the body. Interestingly, negative body image experiences were not found to be represented by the opposite of positive body image experiences as they were each distinct. These findings have direct implications for medical professionals in hospital and rehabilitation settings to understand the importance of body image after spinal cord injury.

The role of microRNAs and retinoid signaling during spinal cord regeneration in the adult newt.

The molecular events after spinal cord injury that lead to the establishment of a permissive environment and epimorphic regeneration remain unclear. Two molecular pathway regulators that may converge to create a spinal cord regeneration-permissive environment in the urodele are retinoic acid (RA) and microRNAs (miRNAs). Recent evidence suggests that RARβ-mediated signaling is necessary for tail and caudal spinal cord regeneration in the adult newt. MicroRNAs are attractive candidates as mediators of retinoid signaling during regeneration, as their pleiotropic effects are vital in situations where global changes in gene expression are required. Thus, the overall aim of this thesis was to determine if miRNAs are involved in tail and caudal spinal cord regeneration in the adult newt, and if they act as regulators and/or effectors of retinoid signaling during this process. I have demonstrated here, for the first time, that multiple miRNAs are dysregulated in response to spinal cord injury in the adult newt, as well as in response to inhibition of retinoid signaling. Two of these miRNAs, miR-133a and miR-1, appear to target RARβ2 transcripts both in vivo and in vitro. Inhibition of RA signaling via RARβ with a selective antagonist, LE135, alters the pattern of expression of these miRNAs, which leads to an inhibition of tail regeneration. These data are indicative of a negative feed back loop, albeit potentially an indirect one. I also aimed to examine which miRNAs are affected by inhibiting RA synthesis during regeneration, and provided a long list of miRNAs that are dysregulated. These data provide the foundation for future studies on the putative roles of these miRNAs, as well as their function in retinoid signaling. Overall, these studies provide the first evidence for a role for miRNAs as mediators of retinoid signaling during caudal spinal cord regeneration in any system.

Surgical principles and minor surgery

UANL

Anatomo-functional magnetic resonance imaging of the spinal cord and its application to the characterization of spinal lesions in cats

Les lésions de la moelle épinière ont un impact significatif sur la qualité de la vie car elles peuvent induire des déficits moteurs (paralysie) et sensoriels. Ces déficits évoluent dans le temps à mesure que le système nerveux central se réorganise, en impliquant des mécanismes physiologiques et neurochimiques encore mal connus. L'ampleur de ces déficits ainsi que le processus de réhabilitation dépendent fortement des voies anatomiques qui ont été altérées dans la moelle épinière. Il est donc crucial de pouvoir attester l'intégrité de la matière blanche après une lésion spinale et évaluer quantitativement l'état fonctionnel des neurones spinaux. Un grand intérêt de l'imagerie par résonance magnétique (IRM) est qu'elle permet d'imager de façon non invasive les propriétés fonctionnelles et anatomiques du système nerveux central. Le premier objectif de ce projet de thèse a été de développer l'IRM de diffusion afin d'évaluer l'intégrité des axones de la matière blanche après une lésion médullaire. Le deuxième objectif a été d'évaluer dans quelle mesure l'IRM fonctionnelle permet de mesurer l'activité des neurones de la moelle épinière. Bien que largement appliquées au cerveau, l'IRM de diffusion et l'IRM fonctionnelle de la moelle épinière sont plus problématiques. Les difficultés associées à l'IRM de la moelle épinière relèvent de sa fine géométrie (environ 1 cm de diamètre chez l'humain), de la présence de mouvements d'origine physiologique (cardiaques et respiratoires) et de la présence d'artefacts de susceptibilité magnétique induits par les inhomogénéités de champ, notamment au niveau des disques intervertébraux et des poumons. L'objectif principal de cette thèse a donc été de développer des méthodes permettant de contourner ces difficultés. Ce développement a notamment reposé sur l'optimisation des paramètres d'acquisition d'images anatomiques, d'images pondérées en diffusion et de données fonctionnelles chez le chat et chez l'humain sur un IRM à 3 Tesla. En outre, diverses stratégies ont été étudiées afin de corriger les distorsions d'images induites par les artefacts de susceptibilité magnétique, et une étude a été menée sur la sensibilité et la spécificité de l'IRM fonctionnelle de la moelle épinière. Les résultats de ces études démontrent la faisabilité d'acquérir des images pondérées en diffusion de haute qualité, et d'évaluer l'intégrité de voies spinales spécifiques après lésion complète et partielle. De plus, l'activité des neurones spinaux a pu être détectée par IRM fonctionnelle chez des chats anesthésiés. Bien qu'encourageants, ces résultats mettent en lumière la nécessité de développer davantage ces nouvelles techniques. L'existence d'un outil de neuroimagerie fiable et robuste, capable de confirmer les paramètres cliniques, permettrait d'améliorer le diagnostic et le pronostic chez les patients atteints de lésions médullaires. Un des enjeux majeurs serait de suivre et de valider l'effet de diverses stratégies thérapeutiques. De telles outils représentent un espoir immense pour nombre de personnes souffrant de traumatismes et de maladies neurodégénératives telles que les lésions de la moelle épinière, les tumeurs spinales, la sclérose en plaques et la sclérose latérale amyotrophique.

L’effet des différents facteurs de croissance sur la viabilité et la prolifération des ostéoblastes scoliotiques

Résumé: La Scoliose Idiopathique de l’Adolescent (SIA) est une condition débilitante qui peut avoir comme résultat une douleur importante, une altération du fonctionnement quotidien et une détérioration de la qualité de vie. Pour les patients qui ne répondent pas au traitement conservateur, la fusion vertébrale, en utilisant des greffes osseuses, est devenue un traitement de choix pour stabiliser la colonne. Des connaissances plus pointues à propos des facteurs impliqués dans l’ostéogénèse et la formation de l’os peuvent raccourcir le processus de guérison et permettre aux patients de réintégrer leurs activités dans un laps de temps plus court. Les plaquettes peuvent jouer un rôle important dans la première étape de la guérison des fractures car elles sont une source autologue de plusieurs facteurs de croissance qui soutiennent la prolifération et la différenciation des ostéoblastes in vivo et in vitro. Au cours des dernières années, plusieurs tentatives ont été réalisées afin de trouver des traitements additionnels pour : 1) Raccourcir le temps de guérison des fractures relativement long ; 2) Obtenir une plus courte période de convalescence pour les patients qui ont besoin de prothèses ; 3) Corriger plus facilement plusieurs maladies congénitales; 4) Améliorer le processus de fusion vertébrale et 5) Développer de nouvelles approches thérapeutiques, notamment au niveau des processus régularisant le remodelage osseux et la régénération des tissus osseux. Dans le cadre de la présente étude, j’ai étudié la contribution possible du facteur de croissance de l’insuline (IGF) et du facteur vasculaire endothélial de croissance (VEGF) sur la maturation de l’ostéoblaste scoliotique dans des cultures cellulaires in vitro et j’ai comparé les résultats avec celles obtenues dans les mêmes conditions mais en stimulant les ostéoblastes avec de la mélatonine. Cette étude préliminaire a été réalisée sur des échantillons d’os récoltés de quatre patients atteints par la Scoliose Idiopathique de l‘Adolescent (SIA), ainsi que sur des échantillons d’os issus de quatre sujets témoins (cas traumatiques). Les résultats montrent que l’IGFs et le VEGFs possèdent une action d’inhibition sur la prolifération d’ostéoblastes scoliotiques et non scoliotiques, et que cette action est proportionnelle à la concentration de ces facteurs. Les ostéoblastes scoliotiques tendent à avoir une prolifération cellulaire plus rapide et plus élevée que les témoins non scoliotiques. De façon générale les ostéoblastes provenant de patients scoliotiques ont une ostéogénèse in vitro plus accélérée que le sujet non scoliotique. De plus, il semble que la mélatonine joue un rôle physiologique dans la différenciation de l’ostéoblaste scoliotique et elle semble aider à avoir une différenciation plus précoce que chez les non traités. Les ostéoblastes scoliotiques expriment un défaut d’expression de l’IGF 1 et d’IGF 1R en présence de la mélatonine. En conclusion, le VEGF A et l’IGF 1 peuvent également promouvoir la différenciation et la prolifération des ostéoblastes humains scoliotiques en culture primaire.

Src family kinases are required for limb trajectory selection by spinal motor axons

Signal relay by guidance receptors at the axonal growth cone is a process essential for the assembly of a functional nervous system. We investigated the in vivo function of Src family kinases (SFKs) as growth cone guidance signaling intermediates in the context of spinal lateral motor column (LMC) motor axon projection toward the ventral or dorsal limb mesenchyme. Using in situ mRNA detection we determined that Src and Fyn are expressed in LMC motor neurons of chick and mouse embryos at the time of limb trajectory selection. Inhibition of SFK activity by C-terminal Src kinase (Csk) overexpression in chickLMCaxons using in ovo electroporation resulted inLMC axons selecting the inappropriate dorsoventral trajectory within the limb mesenchyme, with medial LMC axon projecting into the dorsal and ventral limb nerve with apparently random incidence. We also detected LMC axon trajectory choice errors in Src mutant mice demonstrating a nonredundant role for Src in motor axon guidance in agreement with gain and loss of Src function in chickLMCneurons which led to the redirection ofLMCaxons. Finally, Csk-mediated SFK inhibition attenuated the retargeting ofLMCaxons caused by EphA or EphB over-expression, implying the participation of SFKs in Eph-mediated LMC motor axon guidance. In summary, our findings demonstrate that SFKs are essential for motor axon guidance and suggest that they play an important role in relaying ephrin:Eph signals that mediate the selection of motor axon trajectory in the limb.

Lumbar-sacral pedicle screw insertion with preoperative CT-based navigation

Objectif: Nous avons effectué une étude chez 135 patients ayant subis une chirurgie lombo-sacrée avec vissage pédiculaire sous navigation par tomographie axiale. Nous avons évalué la précision des vis pédiculaires et les résultats cliniques. Méthodes: Cette étude comporte 44 hommes et 91 femmes (âge moyen=61, intervalle 24-90 ans). Les diamètres, longueurs et trajectoires des 836 vis ont été planifiés en préopératoire avec un système de navigation (SNN, Surgical Navigation Network, Mississauga). Les patients ont subi une fusion lombaire (55), lombo-sacrée (73) et thoraco-lombo-sacrée (7). La perforation pédiculaire, la longueur des vis et les spondylolisthesis sont évalués par tomographies axiales postopératoires. Le niveau de douleur est mesuré par autoévaluations, échelles visuelles analogues et questionnaires (Oswestry et SF-36). La fusion osseuse a été évaluée par l’examen des radiographies postopératoires. Résultats: Une perforation des pédicules est présente pour 49/836 (5.9%) des vis (2.4% latéral, 1.7% inférieur, 1.1% supérieur, 0.7% médial). Les erreurs ont été mineures (0.1-2mm, 46/49) ou intermédiaires (2.1 - 4mm, 3/49 en latéral). Il y a aucune erreur majeure (≥ 4.1mm). Certaines vis ont été jugées trop longues (66/836, 8%). Le temps moyen pour insérer une vis en navigation a été de 19.1 minutes de l΄application au retrait du cadre de référence. Un an postopératoire on note une amélioration de la douleur des jambes et lombaire de 72% et 48% en moyenne respectivement. L’amélioration reste stable après 2 ans. La dégénérescence radiologique au dessus et sous la fusion a été retrouvée chez 44 patients (33%) and 3 patients respectivement (2%). Elle est survenue en moyenne 22.2 ± 2.6 mois après la chirurgie. Les fusions se terminant à L2 ont été associées à plus de dégénération (14/25, 56%). Conclusion: La navigation spinale basée sur des images tomographiques préopératoires est une technique sécuritaire et précise. Elle donne de bons résultats à court terme justifiant l’investissement de temps chirurgical. La dégénérescence segmentaire peut avoir un impact négatif sur les résultats radiologique et cliniques.