965 resultados para Electric Stimulation Therapy.
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Occupational therapists need to embrace the use of mainstream technology in their quest to ensure that therapy remains current and meaningful to their clients. Technology can be useful to improve both functional independence and occupational performance. This opinion piece introduces how occupational therapists can apply mainstream technologies, including information and communication technologies such as the internet, computer software, portable devices and computer games, in their everyday interventions.
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In this work, the properties of strained tetrahedrally bonded materials are explored theoretically, with special focus on group-III nitrides. In order to do so, a multiscale approach is taken: accurate quantitative calculations of material properties are carried out in a quantum first-principles frame, for small systems. These properties are then extrapolated and empirical methods are employed to make predictions for larger systems, such as alloys or nanostructures. We focus our attention on elasticity and electric polarization in semiconductors. These quantities serve as input for the calculation of the optoelectronic properties of these systems. Regarding the methods employed, our first-principles calculations use highly- accurate density functional theory (DFT) within both standard Kohn-Sham and generalized (hybrid functional) Kohn-Sham approaches. We have developed our own empirical methods, including valence force field (VFF) and a point-dipole model for the calculation of local polarization and local polarization potential. Our local polarization model gives insight for the first time to local fluctuations of the electric polarization at an atomistic level. At the continuum level, we have studied composition-engineering optimization of nitride nanostructures for built-in electrostatic field reduction, and have developed a highly efficient hybrid analytical-numerical staggered-grid computational implementation of continuum elasticity theory, that is used to treat larger systems, such as quantum dots.
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Mesenchymal stem cells (MSCs) are currently under investigation as repair agents in the preservation of cardiac function following myocardial infarction (MI). However concerns have emerged regarding the safety of acute intracoronary (IC) MSC delivery specifically related to mortality, micro-infarction and microvascular flow restriction post cell therapy in animal models. This thesis aimed to firstly identify an optimal dose of MSC that could be tolerated when delivered via the coronary artery in a porcine model of acute MI (AMI). Initial dosing studies identified 25x106 MSC to be a safe MSC cell dose, however, angiographic observations from these studies recognised that on delivery of MSC there was a significant adverse decrease in distal blood flow within the artery. This observation along with additional supportive data in the literature (published during the course of this thesis) suggested MSC may be contributing to such adverse events through the propagation of thrombosis. Therefore further studies aimed to investigate the innate prothrombotic activity of MSC. Expression of the initiator of the coagulation cascade initiator tissue factor (TF) on MSC was detected in high levels on the surface of these cells. MSC-derived TF antigen was catalytically active, capable of supporting thrombin generation in vitro and enhancing platelet-driven thrombus deposition on collagen under flow. Infusion of MSC via IC route was associated with a decreased coronary flow reserve when delivered but not when coadministered with an antithrombin agent heparin. Heparin also reduced MSC-associated in situ thrombosis incorporating platelets and VWF in the microvasculature. Heparin-assisted MSC delivery reduced acute apoptosis and significantly improved infarct size, left ventricular ejection fraction, LV volumes, wall motion and scar formation at 6 weeks post AMI. In addition, this thesis investigated the paracrine factors secreted by MSC, in particular focusing on the effect on cardiac repair of a novel MSC-paracrine factor SPARCL1. In summary this work provides new insight into the mechanism by which MSC may be deleterious when delivered by an IC route and a means of abrogating this effect. Moreover we present new data on the MSC secretome with elucidation of the challenges encountered using a single paracrine factor cardiac repair strategy.
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This thesis work covered the fabrication and characterisation of impedance sensors for biological applications aiming in particular to the cytotoxicity monitoring of cultured cells exposed to different kind of chemical compounds and drugs and to the identification of different types of biological tissue (fat, muscles, nerves) using a sensor fabricated on the tip of a commercially available needle during peripheral nerve block procedures. Gold impedance electrodes have been successfully fabricated for impedance measurement on cells cultured on the electrode surface which was modified with the fabrication of gold nanopillars. These nanostructures have a height of 60nm or 100nm and they have highly ordered layout as they are fabricated through the e-beam technique. The fabrication of the threedimensional structures on the interdigitated electrodes was supposed to improve the sensitivity of the ECIS (electric cell-substrate impedance sensing) measurement while monitoring the cytotoxicity effects of two different drugs (Antrodia Camphorata extract and Nicotine) on three different cell lines (HeLa, A549 and BALBc 3T3) cultured on the impedance devices and change the morphology of the cells growing on the nanostructured electrodes. The fabrication of the nanostructures was achieved combining techniques like UV lithography, metal lift-off, evaporation and e-beam lithography techniques. The electrodes were packaged using a pressure sensitive, medical grade adhesive double-sided tape. The electrodes were then characterised with the aid of AFM and SEM imaging which confirmed the success of the fabrication processes showing the nanopillars fabricated with the right layout and dimensions figures. The introduction of nanopillars on the impedance electrodes, however, did not improve much the sensitivity of the assay with the exception of tests carried out with Nicotine. HeLa and A549 cells appeared to grow in a different way on the two surfaces, while no differences where noticed on the BALBc 3T3 cells. Impedance measurements obtained with the dead cells on the negative control electrodes or the test electrodes with the drugs can be compared to those done on the electrodes containing just media in the tested volume (as no cells are attached and cover the electrode surface). The impedance figures recorded using these electrodes were between 1.5kΩ and 2.5 kΩ, while the figures recorded on confluent cell layers range between 4kΩ and 5.5kΩ with peaks of almost 7 kΩ if there was more than one layer of cells growing on each other. There was then a very clear separation between the values of living cell compared to the dead ones which was almost 2.5 - 3kΩ. In this way it was very easy to determine whether the drugs affected the cells normal life cycle on not. However, little or no differences were noticed in the impedance analysis carried out on the two different kinds of electrodes using cultured cells. An increase of sensitivity was noticed only in a couple of experiments carried out on A549 cells growing on the nanostructured electrodes and exposed to different concentration of a solution containing Nicotine. More experiments to achieve a higher number of statistical evidences will be needed to prove these findings with an absolute confidence. The smart needle project aimed to reduce the limitations of the Electrical Nerve Stimulation (ENS) and the Ultra Sound Guided peripheral nerve block techniques giving the clinicians an additional tool for performing correctly the peripheral nerve block. Bioimpedance, as measured at the needle tip, provides additional information on needle tip location, thereby facilitating detection of intraneural needle placement. Using the needle as a precision instrument and guidance tool may provide additional information as to needle tip location and enhance safety in regional anaesthesia. In the time analysis, with the frequency fixed at 10kHz and the samples kept at 12°C, the approximate range for muscle bioimpedance was 203 – 616 Ω, the approximate bioimpedance range for fat was 5.02 - 17.8 kΩ and the approximate range for connective tissue was 790 Ω – 1.55 kΩ. While when the samples were heated at 37°C and measured again at 10kHz, the approximate bioimpedance range for muscle was 100-175Ω. The approximate bioimpedance range of fat was 627 Ω - 3.2 kΩ and the range for connective tissue was 221-540Ω. In the experiments done on the fresh slaughtered lamb carcass, replicating a scenario close to the real application, the impedance values recorded for fat were around 17 kΩ, for muscle and lean tissue around 1.3 kΩ while the nervous structures had an impedance value of 2.9 kΩ. With the data collected during this research, it was possible to conclude that measurements of bioimpedance at the needle tip location can give valuable information to the clinicians performing a peripheral nerve block procedure as the separation (in terms of impedance figures) was very marked between the different type of tissues. It is then feasible to use an impedance electrode fabricated on the needle tip to differentiate several tissues from the nerve tissue. Currently, several different methods are being studied to fabricate an impedance electrode on the surface of a commercially available needle used for the peripheral nerve block procedure.
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Case Reports
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BACKGROUND AND AIMS: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) has been shown to act as a negative regulator of T cell function and has been implicated in the regulation of T helper 1 (Th1)/Th2 development and the function of regulatory T cells. Tests were carried out to determine whether anti-CTLA-4 treatment would alter the polarisation of naive T cells in vivo. METHODS: Mice were treated with anti-CTLA-4 monoclonal antibody (mAb) (UC10-4F10) at the time of immunisation or colonic instillation of trinitrobenzene sulfonic acid (TNBS). The cytokines produced by lymph node cells after in vitro antigenic stimulation and the role of indoleamine 2,3 dioxygenase (IDO) and of interleukin-10 (IL-10) were tested, and the survival of mice was monitored. RESULTS: Injection of anti-CTLA-4 mAb in mice during priming induced the development of adaptive CD4(+) regulatory T cells which expressed high levels of ICOS (inducible co-stimulator), secreted IL-4 and IL-10. This treatment inhibited Th1 memory responses in vivo and repressed experimental intestinal inflammation. The anti-CTLA-4-induced amelioration of disease correlated with IDO expression and infiltration of ICOS(high) Foxp3(+) T cells in the intestine, suggesting that anti-CTLA-4 acted indirectly through the development of regulatory T cells producing IL-10 and inducing IDO. CONCLUSIONS: These observations emphasise the synergy between IL-10 and IDO as anti-inflammatory agents and highlight anti-CTLA-4 treatment as a potential novel immunotherapeutic approach for inducing adaptive regulatory T cells.
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The elderly population has been neglected by the traditional approach to clinical breast cancer research. Elderly women have been underrepresented in breast cancer clinical trials, with the majority of studies being restricted to patients aged < 70 years. Elderly patients frequently have comorbidities and/or impaired organ function. These facts may often lead to death from causes other than cancer, thus nullifying any possible benefit of adjuvant treatment; furthermore, they render extrapolation of standard treatment recommendations to the elderly potentially hazardous, particularly with respect to chemotherapy. Therefore, specific clinical trials are needed to investigate adjuvant treatments tailored for the heterogeneous older population.
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BACKGROUND: Women with hormone-responsive metastatic breast cancer (MBC) may respond to or have stable disease with a number of hormone therapies. We explored the efficacy and safety of the steroidal aromatase inactivator exemestane as first-line hormonal therapy in MBC in postmenopausal women. PATIENTS AND METHODS: Patients with measurable disease were eligible if they had received no prior hormone therapy for metastatic disease and had hormone receptor positive disease or hormone receptor unknown disease with a long disease-free interval from adjuvant therapy. They were randomized to tamoxifen 20 mg/day or exemestane 25 mg/day in this open-label study. RESULTS: Blinded independently reviewed response rates for exemestane and tamoxifen were 41% and 17%, respectively. Fifty-seven per cent of exemestane- and 42% of tamoxifen-treated patients experienced clinical benefit, defined as complete or partial response, or disease stabilization lasting at least 6 months. There was a low incidence of severe flushing, sweating, nausea and edema in women who received exemestane. One exemestane-treated patient had a pulmonary embolism with grade 4 dyspnea. CONCLUSIONS: Exemestane is well tolerated and active in the first-line treatment of hormone-responsive MBC. An ongoing EORTC phase III trial is comparing the efficacy, measuring time-to-disease progression, of exemestane and tamoxifen.
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BACKGROUND AND PURPOSE: Docetaxel is an active agent in the treatment of metastatic breast cancer. We evaluated the feasibility of docetaxel-based sequential and combination regimens as adjuvant therapies for patients with node-positive breast cancer. PATIENTS AND METHODS: Three consecutive groups of patients with node-positive breast cancer or locally-advanced disease, aged < or = 70 years, received one of the following regimens: a) sequential A-->T-->CMF: doxorubicin 75 mg/m2 q 3 weeks x 3, followed by docetaxel 100 mg/m2 q 3 weeks x 3, followed by i.v. CMF days 1 + 8 q 4 weeks x 3; b) sequential accelerated A-->T-->CMF: A and T were administered at the same doses q 2 weeks; c) combination therapy: doxorubicin 50 mg/m2 + docetaxel 75 mg/m2 q 3 weeks x 4, followed by CMF x 4. When indicated, radiotherapy was administered during or after CMF, and tamoxifen started after the end of CMF. RESULTS: Seventy-nine patients have been treated. Median age was 48 years. A 30% rate of early treatment discontinuation was observed in patients receiving the sequential accelerated therapy (23% during A-->T), due principally to severe skin toxicity. Median relative dose-intensity was 100% in the three treatment arms. The incidence of G3-G4 major toxicities by treated patients, was as follows: skin toxicity a: 5%; b: 27%; c: 0%; stomatitis a: 20%; b: 20%; c: 3%. The incidence of neutropenic fever was a: 30%; b: 13%; c: 48%. After a median follow-up of 18 months, no late toxicity has been reported. CONCLUSIONS: The accelerated sequential A-->T-->CMF treatment is not feasible due to an excess of skin toxicity. The sequential non accelerated and the combination regimens are feasible and under evaluation in a phase III trial of adjuvant therapy.
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BACKGROUND: Docetaxel has proven efficacy in metastatic breast cancer. In this pilot study, we explored the efficacy/feasibility of docetaxel-based sequential and combination regimens as adjuvant therapy of node-positive breast cancer. PATIENTS AND METHODS: From March 1996 till March 1998, four consecutive groups of patients with stages II and III breast cancer, aged < or = 70 years, received one of the following regimens: a) sequential Doxorubicin (A) --> Docetaxel (T) --> CMF (Cyclophosphamide+Methotrexate+5-Fluorouracil): A 75 mg/m q 3 wks x 3, followed by T100 mg/m2 q 3 wks x 3, followed by i.v. CMF Days 1+8 q 4 wks x 3; b) sequential accelerated A --> T --> CMF: A and T administered at the same doses q 2 wks with Lenograstin support; c) combination therapy: A 50 mg/m2 + T 75 mg/m2 q 3 wks x 4, followed by CMF x 4; d) sequential T --> A --> CMF: T and A, administered as in group a), with the reverse sequence. When indicated, radiotherapy was administered during or after CMF, and Tamoxifen after CMF. RESULTS: Ninety-three patients were treated. The median age was 48 years (29-66) and the median number of positive axillary nodes was 6 (1-25). Tumors were operable in 94% and locally advanced in 6% of cases. Pathological tumor size was >2 cm in 72% of cases. There were 21 relapses, (18 systemic, 3 locoregional) and 11 patients (12%) have died from disease progression. At median follow-up of 39 months (6-57), overall survival (OS) was 87% (95% CI, 79-94%) and disease-free survival (DFS) was 76% (95% CI, 67%-85%). CONCLUSION: The efficacy of these docetaxel-based regimens, in terms of OS and DFS, appears to be at least as good as standard anthracycline-based adjuvant chemotherapy (CT), in similar high-risk patient populations.
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PURPOSE: Taxanes (paclitaxel or docetaxel) have been sequenced or combined with anthracyclines (doxorubicin or epirubicin) for the first-line treatment of advanced breast cancer. This meta-analysis uses data from all relevant trials to detect any advantages of taxanes in terms of tumor response, progression-free survival (PFS), and survival. PATIENTS AND METHODS: Individual patient data were collected on eight randomized combination trials comparing anthracyclines + taxanes (+ cyclophosphamide in one trial) with anthracyclines + cyclophosphamide (+ fluorouracil in four trials), and on three single-agent trials comparing taxanes with anthracyclines. Combination trials included 3,034 patients; single-agent trials included 919 patients. RESULTS: Median follow-up of living patients was 43 months, median survival was 19.3 months, and median PFS was 7.1 months. In single-agent trials, response rates were similar in the taxanes (38%) and in the anthracyclines (33%) arms (P = .08). The hazard ratios for taxanes compared with anthracyclines were 1.19 (95% CI, 1.04 to 1.36; P = .011) for PFS and 1.01 (95% CI, 0.88 to 1.16; P = .90) for survival. In combination trials, response rates were 57% (10% complete) in taxane-based combinations and 46% (6% complete) in control arms (P < .001). The hazard ratios for taxane-based combinations compared with control arms were 0.92 (95% CI, 0.85 to 0.99; P = .031) for PFS and 0.95 (95% CI, 0.88 to 1.03; P = .24) for survival. CONCLUSION: Taxanes were significantly worse than single-agent anthracyclines in terms of PFS, but not in terms of response rates or survival. Taxane-based combinations were significantly better than anthracycline-based combinations in terms of response rates and PFS, but not in terms of survival.
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SCOPUS: ar.j
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While cochlear implants (CIs) usually provide high levels of speech recognition in quiet, speech recognition in noise remains challenging. To overcome these difficulties, it is important to understand how implanted listeners separate a target signal from interferers. Stream segregation has been studied extensively in both normal and electric hearing, as a function of place of stimulation. However, the effects of pulse rate, independent of place, on the perceptual grouping of sequential sounds in electric hearing have not yet been investigated. A rhythm detection task was used to measure stream segregation. The results of this study suggest that while CI listeners can segregate streams based on differences in pulse rate alone, the amount of stream segregation observed decreases as the base pulse rate increases. Further investigation of the perceptual dimensions encoded by the pulse rate and the effect of sequential presentation of different stimulation rates on perception could be beneficial for the future development of speech processing strategies for CIs.
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The concept of focal therapy is rapidly evolving and gaining popularity from both physician and patient perspectives. We review the rationale, candidate selection, and results of the first clinical studies of focal cryoablation for selected patients with low volume and low- to low-moderate-risk features of prostate cancer as an alternative to whole-gland treatment. In spite of improved understanding of the tumor biology of early stage disease, we currently have limited tools to select appropriate patients with low- to low-moderate risk unifocal or unilateral prostate cancer who may be amenable to focal therapy. From a technical point, a number of ablative treatment options for focal therapy are available, with cryoablation having the most clinical experience. Recently, several reports have been published from single and multi-institutional studies that discuss focal therapy as a reasonable balance between cancer control and quality-of-life outcomes. Retrospective pathologic data from large prostatectomy series, however, do not clearly reveal valid and reproducible criteria to select appropriate candidates for focal cryoablation because of the complexity of tumorigenesis in early stage disease. At this time, a more feasible option remains hemiablation of the prostate with reasonable certainty about the absence of clinically significant cancer lesion(s) on the contralateral side of the prostate based on three-dimensional transperineal prostate biopsy mapping studies. Minimally invasive, parenchyma-preserving cryoablation can be considered as a potential feasible option in the treatment armamentarium of early stage, localized prostate cancer in appropriately selected candidates. There is a need to further test this technique in randomized, multicenter clinical trials.
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BACKGROUND: Sensor-augmented pump therapy (SAPT) integrates real-time continuous glucose monitoring (RT-CGM) with continuous subcutaneous insulin infusion (CSII) and offers an alternative to multiple daily injections (MDI). Previous studies provide evidence that SAPT may improve clinical outcomes among people with type 1 diabetes. Sensor-Augmented Pump Therapy for A1c Reduction (STAR) 3 is a multicenter randomized controlled trial comparing the efficacy of SAPT to that of MDI in subjects with type 1 diabetes. METHODS: Subjects were randomized to either continue with MDI or transition to SAPT for 1 year. Subjects in the MDI cohort were allowed to transition to SAPT for 6 months after completion of the study. SAPT subjects who completed the study were also allowed to continue for 6 months. The primary end point was the difference between treatment groups in change in hemoglobin A1c (HbA1c) percentage from baseline to 1 year of treatment. Secondary end points included percentage of subjects with HbA1c < or =7% and without severe hypoglycemia, as well as area under the curve of time spent in normal glycemic ranges. Tertiary end points include percentage of subjects with HbA1c < or =7%, key safety end points, user satisfaction, and responses on standardized assessments. RESULTS: A total of 495 subjects were enrolled, and the baseline characteristics similar between the SAPT and MDI groups. Study completion is anticipated in June 2010. CONCLUSIONS: Results of this randomized controlled trial should help establish whether an integrated RT-CGM and CSII system benefits patients with type 1 diabetes more than MDI.