923 resultados para Stereotactic Localization


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Background: As the long-term efficacy of stereotactic body radiation therapy (SBRT) becomes established and other prostate cancer treatment approaches are refined and improved, examination of quality of life (QOL) following prostate cancer treatment is critical in driving both patient and clinical treatment decisions. We present the first study to compare QOL after SBRT and radical prostatectomy, with QOL assessed at approximately the same times pre- and post-treatment and using the same validated QOL instrument. Methods: Patients with clinically localized prostate cancer were treated with either radical prostatectomy (n = 123 Spanish patients) or SBRT (n = 216 American patients). QOL was assessed using the Expanded Prostate Cancer Index Composite (EPIC) grouped into urinary, sexual, and bowel domains. For comparison purposes, SBRT EPIC data at baseline, 3 weeks, 5, 11, 24, and 36 months were compared to surgery data at baseline, 1, 6, 12, 24,and 36 months. Differences in patient characteristics between the two groups were assessed using Chi-squared tests for categorical variables and t-tests for continuous variables. Generalized estimating equation (GEE) models were constructed for each EPIC scale to account for correlation among repeated measures and used to assess the effect of treatment on QOL. Results: The largest differences in QOL occurred in the first 1-6 months after treatment, with larger declines following surgery in urinary and sexual QOL as compared to SBRT, and a larger decline in bowel QOL following SBRT as compared to surgery. Long-term urinary and sexual QOL declines remained clinically significantly lower for surgery patients but not for SBRT patients. Conclusions: Overall, these results may have implications for patient and physician clinical decision making which are often influenced by QOL. These differences in sexual, urinary and bowel QOL should be closely considered in selecting the right treatment, especially in evaluating the value of non-invasive treatments, such as SBRT.

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BACKGROUND: An important signal transduction pathway in plant defence depends on the accumulation of salicylic acid (SA). SA is produced in chloroplasts and the multidrug and toxin extrusion transporter ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5; At4g39030) is necessary for the accumulation of SA after pathogen and abiotic stress. EDS5 is localized at the chloroplast and functions in transporting SA from the chloroplast to the cytoplasm. EDS5 has a homologue called EDS5H (EDS5 HOMOLOGUE; At2g21340) but its relationship to EDS5 has not been described and its function is not known. RESULTS: EDS5H exhibits about 72% similarity and 59% identity to EDS5. In contrast to EDS5 that is induced after pathogen inoculation, EDS5H was constitutively expressed in all green tissues, independently of pathogen infection. Both transporters are located at the envelope of the chloroplast, the compartment of SA biosynthesis. EDS5H is not involved with the accumulation of SA after inoculation with a pathogen or exposure to UV stress. A phylogenetic analysis supports the hypothesis that EDS5H may be an H(+)/organic acid antiporter like EDS5. CONCLUSIONS: The data based on genetic and molecular studies indicate that EDS5H despite its homology to EDS5 does not contribute to pathogen-induced SA accumulation like EDS5. EDS5H most likely transports related substances such as for example phenolic acids, but unlikely SA.

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Patients affected with intra-thoracic recurrences of primary or secondary lung malignancies after a first course of definitive radiotherapy have limited therapeutic options, and they are often treated with a palliative intent. Re-irradiation with stereotactic ablative radiotherapy (SABR) represents an appealing approach, due to the optimized dose distribution that allows for high-dose delivery with better sparing of organs at risk. This strategy has the goal of long-term control and even cure. Aim of this review is to report and discuss published data on re-irradiation with SABR in terms of efficacy and toxicity. Results indicate that thoracic re-irradiation may offer satisfactory disease control, however the data on outcome and toxicity are derived from low quality retrospective studies, and results should be cautiously interpreted. As SABR may be associated with serious toxicity, attention should be paid for an accurate patients' selection.

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Le cancer du poumon est la première cause de mortalité associée au cancer dans le monde. Le traitement curatif des tumeurs pulmonaires non-à-petites-cellules (NSCLC) diagnostiquées à un stade précoce se base sur une approche chirurgicale. Cependant, étant donné les comorbidités liées à la consommation de tabac, dont la bronchopneumopathie chronique occupe la première place, l'éligibilité chirurgicale pour ce type de cancer se trouve fréquemment limitée. Dans ce contexte, l'emploi de la radiothérapie stéréotaxique (SBRT) est une alternative valable chez les patients atteints d'un NSCLC primaire de stade précoce, et qui sont considérés inopérables à cause de leurs comorbidités. Depuis peu seulemement, le spectre de la SBRT a été élargi aux patients atteints d'un deuxième NSCLC primaire (SPLC), faisant suite à un premier NSCLC, traité avec un but curatif. Ils concernent donc des patients ayant déjà subits une intervention chirurgicale au préalable et qui présentent une réserve fonctionnelle pulmonaire extrêmement réduite. Le succès croissant de la SBRT résulte soit d'une efficacité thérapeutique comparables à la chirurgie, soit de sa toxicité qui semble limitée. À notre connaissance, seulement une étude a reporté des issues cliniques de patients affectés par des NSCLC primaires traités par SBRT. Cette dernière a utilisé la tomothérapie comme système d'irradiation (T-SBRT), sur un faible échantillon de patients (n = 27). Concernant l'irradiation des patients présentant des SPLC, la littérature disponible est pauvre et aucune publication a décrit l'utilisation de la T-SBRT. Ces éléments innovants ont donc motivé la rédaction d'un travail de thèse concernant les premières données cliniques de l'expérience faite au CHUV. Du point de vue des effets secondaires, si la pneumonie actinique précoce et tardive survenant au niveau du champ d'irradiation est désormais une complication iatrogène bien connue de la SBRT, une seule étude s'est intéressée à ce sujet dans le cadre de la T-SBRT. De plus, une entité bénigne et transitoire de pneumonie ( ?) a été reconnue depuis peu : la pneumonie organisée radio-induite (OP). Celle-ci semble se chevaucher comme un autre effet iatrogène à l'extérieur du champ d'irradiation. Originellement, cette dernière avait été rapportée dans les suites de la radiothérapie pour les cancer du sein. Elle a été décrite comme étant initialement limitée au champ d'irradiation et successivement pouvant s'étendre dynamiquement en dehors de celui-ci. Nous avons donc supposé que des infiltrats de OP peuvent être présents chez des patients asymptomatiques, et que ce dynamisme pourrait être identifié déjà au sein du champ d'irradiation. Notre étude a démontré que le traitement par T-SBRT garde des issues cliniques très encourageantes, aussi bien pour les tumeurs primaires que pour les SPLC. Entre autre, ce traitement semble avoir une toxicité limitée, et l'existence vraisemblable de la OP, déjà au sein du champ d'irradiation, peut aider les radiologues à différencier les infiltrats radio-induits d'une une récidive tumorale.

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Introduction: Gamma Knife surgery (GKS) is a noninvasive neurosurgical stereotactic procedure, increasingly used as an alternative to open functional procedures. This includes the targeting of the ventrointermediate nucleus of the thalamus (e.g., Vim) for tremor. Objective: To enhance anatomic imaging for Vim GKS using high-field (7 T) MRI and Diffusion Weighted Imaging (DWI). Methods: Five young healthy subjects and two patients were scanned both on 3 and 7 T MRI. The protocol was the same in all cases, and included: T1-weighted (T1w) and DWI at 3T; susceptibility weighted images (SWI) at 7T for the visualization of thalamic subparts. SWI was further integrated into the Gamma Plan Software® (LGP, Elekta Instruments, AB, Sweden) and co-registered with 3T images. A simulation of targeting of the Vim was done using the quadrilatere of Guyot. Furthermore, a correlation with the position of the found target on SWI and also on DWI (after clustering of the different thalamic nuclei) was performed. Results: For the 5 healthy subjects, there was a good correlation between the position of the Vim on SWI, DWI and the GKS targeting. For the patients, on the pretherapeutic acquisitions, SWI helped in positioning the target. For posttherapeutic sequences, SWI supposed position of the Vim matched the corresponding contrast enhancement seen at follow-up MRI. Additionally, on the patient's follow-up T1w images, we could observe a small area of contrast-enhancement corresponding to the target used in GKS (e.g., Vim), which belongs to the Ventral-Lateral-Ventral (VLV) nuclei group. Our clustering method resulted in seven thalamic groups. Conclusion: The use of SWI provided us with a superior resolution and an improved image contrast within the central gray matter, enabling us to directly visualize the Vim. We additionally propose a novel robust method for segmenting the thalamus in seven anatomical groups based on DWI. The localization of the GKS target on the follow-up T1w images, as well as the position of the Vim on 7 T, have been used as a gold standard for the validation of VLV cluster's emplacement. The contrast enhancement corresponding to the targeted area was always localized inside the expected cluster, providing strong evidence of the VLV segmentation accuracy. The anatomical correlation between the direct visualization on 7T and the current targeting methods on 3T (e.g., quadrilatere of Guyot, histological atlases, DWI) seems to show a very good anatomical matching.

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OBJECTIVE: To review the natural course of tumor size and hearing during conservative management of 151 patients with unilateral vestibular schwannoma (VS), and to evaluate the same parameters for the part of the group (n = 84) who were treated by LINAC stereotactic radiosurgery (SRS). METHODS: In prospectively collected data, patients underwent MRI and complete audiovestibular tests at inclusion, during the conservative management period and after SRS. Hearing was graded according to the Gardner-Robertson (GR) scale and tumor size according to Koos. Statistics were performed using Kaplan-Meier survival analysis and multivariate analyses including linear and logistic regression. Specific insight was given to patients with serviceable hearing. RESULTS: During the conservative management period (mean follow-up time: 24 months, range: 6-96), the annual risk of GR class degradation was 6% for GRI and 15% for GR II patients. Hearing loss as an initial symptom was highly predictive of further hearing loss (p = 0.003). Tumor growth reached 25%. For SRS patients, functional hearing preservation was 51% at 1 year and 36% at 3 years. Tumor control was 94 and 91%, respectively. CONCLUSION: In VS patients, hearing loss at the time of diagnosis is a predictor of poorer hearing outcome. LINAC SRS is efficient for tumor control. Patients who preserved their pretreatment hearing presented less hearing loss per year after SRS than before treatment, suggesting a protective effect of SRS when cochlear function can be preserved.

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Within the Predict-IV FP7 project a strategy for measurement of in vitro biokinetics was developed, requiring the characterization of the cellular model used, especially regarding biotransformation, which frequently depends on cytochrome P450 (CYP) activity. The extrahepatic in situ CYP-mediated metabolism is especially relevant in target organ toxicity. In this study, the constitutive mRNA levels and protein localization of different CYP isoforms were investigated in 3D aggregating brain cell cultures. CYP1A1, CYP2B1/B2, CYP2D2/4, CYP2E1 and CYP3A were expressed; CYP1A1 and 2B1 represented almost 80% of the total mRNA content. Double-immunolabeling revealed their presence in astrocytes, in neurons, and to a minor extent in oligodendrocytes, confirming the cell-specific localization of CYPs in the brain. These results together with the recently reported formation of an amiodarone metabolite following repeated exposure suggest that this cell culture system possesses some metabolic potential, most likely contributing to its high performance in neurotoxicological studies and support the use of this model in studying brain neurotoxicity involving mechanisms of toxication/detoxication.

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Objective To evaluate the utility of a new multimodal image-guided intervention technique to detect epileptogenic areas with a gamma probe as compared with intraoperative electrocorticography. Materials and Methods Two symptomatic patients with refractory epilepsy underwent magnetic resonance imaging, videoelectroencephalography, brain SPECT scan, neuropsychological evaluation and were submitted to gamma probe-assisted surgery. Results In patient 1, maximum radioactive count was initially observed on the temporal gyrus at about 3.5 cm posteriorly to the tip of the left temporal lobe. After corticotomy, the gamma probe indicated maximum count at the head of the hippocampus, in agreement with the findings of intraoperative electrocorticography. In patient 2, maximum count was observed in the occipital region at the transition between the temporal and parietal lobes (right hemisphere). During the surgery, the area of epileptogenic activity mapped at electrocorticography was also delimited, demarcated, and compared with the gamma probe findings. After lesionectomy, new radioactive counts were performed both in the patients and on the surgical specimens (ex-vivo). Conclusion The comparison between intraoperative electrocorticography and gamma probe-assisted surgery showed similarity of both methods. The advantages of gamma probe include: noninvasiveness, low cost and capacity to demonstrate decrease in the radioactive activity at the site of excision after lesionectomy.

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Objectif : D'analyser l'évolution naturelle de la taille de la tumeur et de l'audition chez 151 patients avec schwannome vestibulaire (VS) en suivi et d'évaluer les mêmes paramètres pour une partie du group traité par Radiochirurgie Stéréotaxique Linac (SRS). Méthodes: Etude prospective des patients bilantés par IRM et tests audio-vestibulaires à l'inclusion, pendant la période du suivi et après SRS. L'audition a été gradé selon l'échelle de Gardner-Robertson (GR) et la taille tumorale selon l'échelle de Koos. L'analyse statistique inclut l'analyse de survie de Kaplan-Meier, analyse multivariée avec régression linéaire et logistique. Les patients avec une audition utile ont étés spécifiquement analysés. Résultats: Pendant la période du suivi (moyenne 24 mois, déviation 6-96), le risqué annuel de dégradation de la classe GR était 6% pour les patients GRI et 15% pour les GRII. La perte auditive comme symptôme initial était un facteur signifïcativement prédictif pour une aggravation auditive ultérieure (p=0.003). La croissance tumorale était de 25% à la dernière observation pendant le suivi. Pour les patients traités par Linac, la préservation d'une audition utile était 51% à 1 an et 36% à 3 ans. Le contrôle tumoral était 94 % and 91% respectivement. Conclusion: Chez les patients avec VS, la perte auditive déjà présente au diagnostique est un facteur prédictif négatif pour l'évolution de l'audition. La Radiochirurgie Stéréotaxique Linac est efficace pour le contrôle tumoral. Les patients ayant préservés leur status auditif prétraitement présentent un rythme annuel de perte auditive diminué après SRS compare à celle-ci avant le traitement. Cette constatation suggère un effet protectif potentiel de la SRS, à condition que la fonction cochléaire soit préservée.

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Simultaneous localization and mapping(SLAM) is a very important problem in mobile robotics. Many solutions have been proposed by different scientists during the last two decades, nevertheless few studies have considered the use of multiple sensors simultane¬ously. The solution is on combining several data sources with the aid of an Extended Kalman Filter (EKF). Two approaches are proposed. The first one is to use the ordinary EKF SLAM algorithm for each data source separately in parallel and then at the end of each step, fuse the results into one solution. Another proposed approach is the use of multiple data sources simultaneously in a single filter. The comparison of the computational com¬plexity of the two methods is also presented. The first method is almost four times faster than the second one.

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Background: One of the problems in prostate cancer (CaP) treatment is the appearance of the multidrug resistance phenotype, in which ATP-binding cassette transporters such as multidrug resistance protein 1 (MRP1) play a role. Different localizations of the transporter have been reported, some of them related to the chemoresistant phenotype. Aim: This study aimed to compare the localization of MRP1 in three prostate cell lines (normal, androgen-sensitive, and androgen-independent) in order to understand its possible role in CaP chemoresistance. Methods: MRP1 and caveolae protein markers were detected using confocal microscopy, performing colocalization techniques. Lipid raft isolation made it possible to detect these proteins by Western blot analysis. Caveolae and prostasomes were identified by electron microscopy. Results: We show that MRP1 is found in lipid raft fractions of tumor cells and that the number of caveolae increases with malignancy acquisition. MRP1 is found not only in the plasma membrane associated with lipid rafts but also in cytoplasmic accumulations colocalizing with the prostasome markers Caveolin-1 and CD59, suggesting that in CaP cells, MRP1 is localized in prostasomes. Conclusion: We hypothesize that the presence of MRP1 in prostasomes could serve as a reservoir of MRP1; thus, taking advantage of the release of their content, MRP1 could be translocated to the plasma membrane contributing to the chemoresistant phenotype. The presence of MRP1 in prostasomes could serve as a predictor of malignancy in CaP

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Background: One of the problems in prostate cancer (CaP) treatment is the appearance of the multidrug resistance phenotype, in which ATP-binding cassette transporters such as multidrug resistance protein 1 (MRP1) play a role. Different localizations of the transporter have been reported, some of them related to the chemoresistant phenotype. Aim: This study aimed to compare the localization of MRP1 in three prostate cell lines (normal, androgen-sensitive, and androgen-independent) in order to understand its possible role in CaP chemoresistance. Methods: MRP1 and caveolae protein markers were detected using confocal microscopy, performing colocalization techniques. Lipid raft isolation made it possible to detect these proteins by Western blot analysis. Caveolae and prostasomes were identified by electron microscopy. Results: We show that MRP1 is found in lipid raft fractions of tumor cells and that the number of caveolae increases with malignancy acquisition. MRP1 is found not only in the plasma membrane associated with lipid rafts but also in cytoplasmic accumulations colocalizing with the prostasome markers Caveolin-1 and CD59, suggesting that in CaP cells, MRP1 is localized in prostasomes. Conclusion: We hypothesize that the presence of MRP1 in prostasomes could serve as a reservoir of MRP1; thus, taking advantage of the release of their content, MRP1 could be translocated to the plasma membrane contributing to the chemoresistant phenotype. The presence of MRP1 in prostasomes could serve as a predictor of malignancy in CaP