997 resultados para arc therapy


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The eastern part of the Cordillera Occidental of Ecuador comprises thick buoyant oceanic plateaus associated with island-arc tholeiites and subduction-related calc-alkaline series, accreted to the Ecuadorian Continental Margin from Late Cretaceous to Eocene times. One of these plateau sequences, the Guaranda Oceanic Plateau is considered as remnant of the Caribbean-Colombian Oceanic Province (CCOP) accreted to the Ecuadorian Margin in the Maastrichtien. Samples studied in this paper were taken from four cross-sections through two arc-sequences in the northern part of the Cordillera Occidental of Ecuador, dated as (Rio Cala) or ascribed to (Macuchi) the Late Cretaceous and one arc-like sequence in the Chogon-Colonche Cordillera (Las Orquideas). These three island-arcs can clearly be identified and rest conformably on the CCOP. In all four localities, basalts with abundant large clinopyroxene phenocrysts can be found, mimicking a picritic or ankaramitic facies. This mineralogical particularity, although not uncommon in island arc lavas, hints at a contribution of the CCOP in the genesis of these island arc rocks. The complete petrological and geochemical study of these rocks reveals that some have a primitive island-arc nature (MgO values range from 6 to 11 wt.%). Studied samples display marked Nb, Ta and Ti negative anomalies relative to the adjacent elements in the spidergrams characteristic of subductionrelated magmatism. These rocks are LREE-enriched and their clinopyroxenes show a tholeiitic affinity (FeO(1)-TiO(2) enrichment and CaO depletion from core to rim within a single crystal). The four sampled cross-sections through the island-arc sequences display homogeneous initial Nd, and Pb isotope ratios that suggest a unique mantellic source for these rocks resulting from the mixing of three components: an East-Pacific MORB end-member, an enriched pelagic sediment component, and a HIMU component carried by the CCOP. Indeed, the ankaramite and Mg-basalt sequences that form part of the Caribbean-Colombian Oceanic Plateau are radiogenically enriched in (206)Pb/(204)Pb and (207)Pb/(204)Pb and contain a HIMU component similar to that observed in the Gorgona basalts and Galapagos lavas. The subduction zone that generated the Late Cretaceous arcs occurred far from the continental margin, in an oceanic environment. This implies that no terrigenous detrital sediments interacted with the source at this period. Thus, the enriched component can only result from the melting of subducted pelagic sediments. We have thus defined the East-Pacific MORB, enriched (cherts, pelagic sediments) and HIMU components in an attempt to constrain and model the genesis of the studied island-arc magmatism, using a compilation of carefully selected isotopic data from literature according to rock age and paleogeographic location at the time of arc edification. Tripolar mixing models reveal that proportions of 12-15 wt.% of the HIMU component, 7-15 wt.% of the pelagic sediment end-member and 70-75 wt.% of an East-pacific MORB end-member are needed to explain the measured isotope ratios. These surprisingly high proportions of the HIMU/CCOP component could be explained by the young age of the oceanic plateau (5-15 Ma) during the Late Cretaceous arc emplacement. The CCOP, basement of these arc sequences, was probably still hot and easily assimilated at the island-arc lava source. (C) 2008 Elsevier Ltd. All rights reserved,

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This study was to evaluate the treatment dosimetry, efficacy and toxicity of intensity modulated radiation therapy (IMRT) and fractionated stereotactic radiotherapy (FSRT) in the management of infratentorial ependymoma. Between 1999 and 2007, seven children (median age, 3.1 years) with infratentorial ependymoma were planned with either IMRT (3 patients) or SFRT (4 patients), the latter after conventional posterior fossa irradiation. Two children underwent gross total resection. Median prescribed dose was 59.4 Gy (range, 55.8-60). The median follow-up for surviving patients was 4.8 years (range, 1.3-8). IMRT (median dose, 59.4 Gy) and FSRT (median dose, 55.8 Gy) achieved similar optimal target coverage. Percentages of maximum doses delivered to the cochleae (59.5 vs 85.0% Gy; P = 0.05) were significantly inferior with IMRT, when compared to FSRT planning. Percentages of maximum doses administered to the pituitary gland (38.2 vs 20.1%; P = 0.05) and optic chiasm (38.1 vs 14.1%; P = 0.001) were, however, significantly higher with IMRT, when compared to FSRT planning. No recurrences were observed at the last follow-up. The estimated 3-year progression-free survival and overall survival were 87.5 and 100%, respectively. No grade >1 acute toxicity was observed. Two patients presented late adverse events (grade 2 hypoacousia) during follow-up, without cognitive impairment. IMRT or FSRT for infratentorial ependymomas is effective and associated with a tolerable toxicity level. Both treatment techniques were able to capitalize their intrinsic conformal ability to deliver high-dose radiation. Larger series of patients treated with these two modalities will be necessary to more fully evaluate these delivery techniques.

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OBJECTIVES: To determine HIV-1 RNA in cerebrospinal fluid (CSF) of successfully treated patients and to evaluate if combination antiretroviral treatments with higher central nervous system penetration-effectiveness (CPE) achieve better CSF viral suppression. METHODS: Viral loads (VLs) and drug concentrations of lopinavir, atazanavir, and efavirenz were measured in plasma and CSF. The CPE was calculated using 2 different methods. RESULTS: The authors analyzed 87 CSF samples of 60 patients. In 4 CSF samples, HIV-1 RNA was detectable with 43-82 copies per milliliter. Median CPE in patients with detectable CSF VL was significantly lower compared with individuals with undetectable VL: CPE of 1.0 (range, 1.0-1.5) versus 2.3 (range, 1.0-3.5) using the method of 2008 (P = 0.011) and CPE of 6 (range, 6-8) versus 8 (range, 5-12) using the method of 2010 (P = 0.022). The extrapolated CSF trough levels for atazanavir (n = 12) were clearly above the 50% inhibitory concentration (IC50) in only 25% of samples; both patients on atazanavir/ritonavir with detectable CSF HIV-1 RNA had trough levels in the range of the presumed IC50. The extrapolated CSF trough level for lopinavir (n = 42) and efavirenz (n = 18) were above the IC50 in 98% and 78%, respectively, of samples, including the patients with detectable CSF HIV-1 RNA. CONCLUSIONS: This study suggests that treatment regimens with high intracerebral efficacy reflected by a high CPE score are essential to achieve CSF HIV-1 RNA suppression. The CPE score including all drug components was a better predictor for treatment failure in the CSF than the sole concentrations of protease inhibitor or nonnucleoside reverse transcriptase inhibitor in plasma or CSF.

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OBJECTIVE: When we examined a previously published prospective multi-center clinical trial in which complete denture-wearers were followed over a period of 2 years, we found that about 30% of the variability in the clinical wear data of denture teeth was due to unknown characteristics of the subjects. In the second part of the study, we try to identify which patient- and therapy-related factors may explain some of this variability. METHODS: The clinical wear data of denture teeth at different recall times (6, 12, 18, 24 months) in 89 subjects (at baseline) were correlated with the following parameters, which may all have an influence on the wear of denture teeth: age, gender, bruxism as reported by the subjects, number of prostheses used so far, time since last extraction, smoking, fit of dentures as judged by the subject and the clinician, average denture wearing time and wearing of denture during the night. To evaluate the influence of the different patient- and therapy-related variables, both a univariate analysis (one extra factor to the model) and a multivariate analysis were carried out using linear mixed models with the variable Log mean as the outcome. RESULTS: None of the patient- and therapy-related parameters showed a statistically significant effect on the wear of denture teeth. There was, however, a trend for women to show less wear compared to men and a trend of decreasing wear with increasing age. SIGNIFICANCE: Further research is required to identify the factors which are responsible for the high variability observed between the subjects regarding clinical wear data.

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Gene transfer that relies on integrating vectors often suffers from epigenetic or regulatory effects that influence the expression of the therapeutic gene and=or of cellular genes located near the vector integration site in the chromosome. Insulator elements act to block gene activation by enhancers, while chromatin domain boundary or barrier sequences prevent gene-silencing effects. At present, the modes of action of insulator and barriers are poorly understood, and their use in the context of gene therapies remains to be documented. Using combinations of reporter genes coding for indicator fluorescent proteins, we constructed assay systems that allow the quantification of the insulator or barrier activities of genetic elements in individual cells. This presentation will illustrate how these assay systems were used to identify short DNA elements that insulate nearby genes from activation by viral vector elements, and=or that block the propagation of a silent chromatin structure that leads to gene silencing. We will show that some barrier elements do not merely block repressive effects, but that they can act to stabilize and sustain transgene expression. We will illustrate that this may be beneficial when transgenes are introduced into stem or precursor cells using non-viral vectors, where later differentiation may lead to the silencing of the therapeutic gene. We will show that these elements can be used to maintain efficient transgene expression upon the differentiation of murine precursor cells towards myofibers, in a model of cell therapy for muscle dystrophies.

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Adoptive transfer therapy of in vitro-expanded tumor-specific cytolytic T lymphocytes (CTLs) can mediate objective cancer regression in patients. Yet, technical limitations hamper precise monitoring of posttherapy T cell responses. Here we show in a mouse model that fused single photon emission computed tomography and x-ray computed tomography allows quantitative whole-body imaging of (111)In-oxine-labeled CTLs at tumor sites. Assessment of CTL localization is rapid, noninvasive, three-dimensional, and can be repeated for longitudinal analyses. We compared the effects of lymphodepletion before adoptive transfer on CTL recruitment and report that combined treatment increased intratumoral delivery of CTLs and improved antitumor efficacy. Because (111)In-oxine is a Food and Drug Administration-approved clinical agent, and human SPECT-CT systems are available, this approach should be clinically translatable, insofar as it may assess the efficacy of immunization procedures in individual patients and lead to development of more effective therapies.

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In patients with dementia, Behavioral and Psychological Symptoms of Dementia (BPSD) are frequent findings that accompany deficits caused by cognitive impairment and thus complicate diagnostics, therapy and care. BPSD are a burden both for affected individuals as well as care-givers, and represent a significant challenge for therapy of a patient population with high degree of multi-morbidity. The goal of this therapy-guideline issued by swiss professional associations is to present guidance regarding therapy of BPSD as attendant symptoms in dementia, based on evidence as well as clinical experience. Here it appears to be of particular importance to take into account professional experience, as at this point for most therapeutic options no sufficiently controlled clinical trials are available. A critical discussion of pharmaco-therapeutic intervention is necessary, as this patient-population is particularly vulnerable for medication side-effects. Finally, a particular emphasis is placed on incorporating and systematically reporting psycho-social and nursing options therapeutic intervention.

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INTRODUCTION: Rhabdomyosarcoma is the most frequent primitive orbital malignant tumor in children. If the treatment is started as soon as possible after discovery of the disease, the vital prognosis is considerably better than otherwise. The goal of this paper is to present the new therapeutic protocol and to report our experience in this field. MATERIAL AND METHOD: During the past 35 years, 102 cases of orbital tumors were collected in children under 15 years of age: 5 cases of rhabdomyosarcoma were cared for in our department. At the time of tumor diagnosis, the age of our patients ranged from 3 weeks to 13 years. After a biopsy or excision biopsy, all our cases were treated by chemotherapy with or without radiotherapy. Medication was mostly vincristine, ifosfamide and actinomycine D. When the result of the treatment was not satisfactory, carboplatine and epirubicine, vincristine as well as ifosfamide were given. Radiotherapy was performed only in particular cases or in recurrences. CONCLUSION: Rhabdomyosarcoma is a highly malignant tumor. Although rare, it is the most frequent of malignant tumors in children. It is important to keep it in mind in order to perform a biopsy enabling quick diagnosis and treatment following the modern protocol giving the highest chances of survival to these patients: about 98% in 3 years.

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In the last decades, new technologies have been introduced in the daily clinical practice of the radiation oncologist: 3D-Conformal radiotherapy (RT) became almost universally available, thereafter, intensity modulated RT (IMRT) gained large diffusion, due to its potential impact in improving the clinical outcomes, and more recently, helical and volumetric arc IMRT with image-guided RT are becoming more and more diffused and used for prostate cancer patients. The conventional dose-fractionation results to be the best compromise between the efficacy and the safety of the treatment, but combining new techniques, modern RT allows to overcame one of the major limits of the 'older' RT: the impossibility of delivering higher total doses and/or high dose/fraction. The evidences regarding radiobiology, clinical and technological evolution of RT in prostate cancer have been reported and discussed.

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Hormone replacement therapy (HRT) is an established approach for the treatment and the prevention of osteoporosis. Many studies with bone mineral density as primary outcome have shown significant efficacy. Observational studies have indicated a significant reduction of hip fracture risk in cohorts of women who maintained HRT therapy. The Women's Health Initiative is the first prospective randomised controlled study which showed a positive effect of HRT in terms of reduction of vertebral and hip fractures risk. Unfortunately, this study has been interrupted after 5.2 years because of the unsupportable increase of risk of cardiovascular disease and breast cancer. Compliance with HRT, however, is typically poor because of the potential side effects and possible increased risk of breast or endometrial cancer. Nevertheless, there is now evidence that lower doses of estrogens in elderly women may prevent bone loss while minimizing the side effects seen with higher doses. Combination therapies using low doses estrogen should probably be reserved for patients who continue to fracture on single therapy. Selective estrogen receptor modulators (SERMs) are very interesting drugs. The goal of these agents is to maximize the beneficial effect of estrogen on bone and to minimize or antagonize the deleterious effects on the breast and endometrium. Raloxifene, approved for the prevention and the treatment of osteoporosis, has been shown to reduce the risks of vertebral fracture in large clinical trials. However, they don't reduce non vertebral fractures. Tibolone is a synthetic steroid that increased bone mineral density at lumbar spine and femoral neck. But no trial has been performed with fractures as end point.

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In the 2005-01 trial, we have demonstrated that bortezomib-dexamethasone as induction therapy before autologous stem cell transplantation was superior to vincristine-adriamycin-dexamethasone. We conducted a post-hoc analysis to assess the prognostic impact of initial characteristics as well as response to therapy in patients enrolled in this study. Multivariate analysis showed that ISS stages 2 and 3 and achievement of response less than very good partial response (VGPR) both after induction therapy and after autologous stem cell transplantation were adverse prognostic factors for progression-free survival, the most important one being achievement of response less than VGPR after induction. Progression-free survival was significantly improved with bortezomib-dexamethasone induction therapy in patients with poor-risk cytogenetics and ISS stages 2 and 3 compared with vincristine-adriamycin-dexamethasone. In these 2 groups of patients, achievement of at least VGPR after induction was of major importance. This study is registered with EudraCT (https://eudract.ema.europa.eu; EUDRACT 2005-000537-38) and http://clinicaltrials.gov (NCT00200681).

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OBJECTIVES: HIV infection and exposure to certain antiretroviral drugs is associated with dyslipidemia and increased risk for coronary events. Whether this risk is mediated by highly atherogenic lipoproteins is unclear. We investigated the association of highly atherogenic small dense low-density lipoproteins (LDLs) and apolipoprotein B and coronary events in HIV-infected individuals receiving antiretroviral therapy. METHODS: We conducted a case-control study nested into the Swiss HIV Cohort Study to investigate the association of small dense LDL and apolipoprotein B and coronary events in 98 antiretroviral drug-treated patients with a first coronary event (19 fatal and 79 nonfatal coronary events with 53 definite and 15 possible myocardial infarctions, 11 angioplasties or bypasses) and 393 treated controls matched for age, gender, and smoking status. Lipids were measured by ultracentrifugation. RESULTS: In models including cholesterol, triglycerides, high-density lipoprotein cholesterol, blood pressure, central obesity, diabetes, and family history, there was an independent association between small dense LDL and coronary events [odds ratio (OR) for 1 mg/dL increase: 1.06, 95% confidence interval (CI): 1.00 to 1.11] and apolipoprotein B (OR for 10 mg/dL increase: 1.16, 95% CI: 1.02 to 1.32). When adding HIV and antiretroviral therapy-related variables, ORs were 1.04 (95% CI: 0.99 to 1.10) for small dense LDL and 1.13 (95% CI: 0.99 to 1.30) for apolipoprotein B. In both models, blood pressure and HIV viral load was independently associated with the odds for coronary events. CONCLUSIONS: HIV-infected patients receiving antiretroviral therapy with elevate small dense LDL and apolipoprotein B are at increased risk for coronary events as are patients without sustained HIV suppression.

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Aims.We revisit the vicinity of the microquasar Cygnus X-3 at radio wavelengths. We aim to improve our previous search for possible associated extended radio features/hot spots in the position angle of the Cygnus X-3 relativistic jets focusing on shorter angular scales than previously explored. Methods.Our work is mostly based on analyzing modern survey and archive radio data, mainly including observations carried out with the Very Large Array and the Ryle Telescopes. We also used deep near-infrared images that we obtained in 2005. Results.We present new radio maps of the Cygnus X-3 field computed after combining multi-configuration Very Large Array archive data at 6 cm and different observing runs at 2 cm with the Ryle Telescope. These are probably among the deepest radio images of Cygnus X-3 reported to date at cm wavelengths. Both interferometers reveal an extended radio feature within a few arc-minutes of the microquasar position, thus making our detection more credible. Moreover, this extended emission is possibly non-thermal, although this point still needs confirmation. Its physical connection with the microquasar is tentatively considered under different physical scenarios. We also report on the serendipitous discovery of a likely Fanaroff-Riley type II radio galaxy only away from Cygnus X-3.