Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Medicine (Baltimore) ; 98(39): e17166, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31574822

RESUMEN

BACKGROUND: Muscular fatigue is caused by biochemical alterations that modify the mechanics of muscle contraction, resulting in negative changes in the performance of the contraction. Several resources are studied to mitigate this situation among which we can cite low-level laser therapy (LLLT). The effects of LLLT are being studied in healthy subjects with fibromyalgia and who are athletes, and currently the studies are being performed in spastic muscles with poststroke individuals. The aim will be to evaluate the effects of LLLT on the fatigue of the biceps brachii muscle of healthy individuals and individuals with spastic hemiparesis. METHODS: A cross-sectional, comparative, randomized, placebo, double-blind clinical trial will be divided into 2 phases: phase I shall consist of 30 healthy subjects and phase II of 30 poststroke individuals. The study will consist of 3 groups (control group, placebo group, and LLLT group), and all individuals will pass through all groups, following the randomization criteria. The protocol consists of the application of LLLT in the biceps brachii muscle on the dominant side in healthy individuals and in the hemiparetic side of poststroke individuals, and, subsequently, 3 maximal isometric voluntary contractions (MIVCs) will be performed for 50 seconds in the dynamometer, with an interval of 50 seconds between them. Pain intensity will be evaluated by means of the visual analog scale, and the myoelectric activity by means of surface electromyography associated with the evaluation of muscular strength by means of the dynamometer. The local temperature will be evaluated by infrared thermography and blood lactate concentration through the lactimeter, which will be measured at 4 different times, before the application of the laser (basal), and 3, 15, and 25 minutes after the MIVC.


Asunto(s)
Terapia por Luz de Baja Intensidad/métodos , Fatiga Muscular/efectos de la radiación , Espasticidad Muscular/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Brazo/efectos de la radiación , Estudios Transversales , Método Doble Ciego , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Espasticidad Muscular/fisiopatología , Músculo Esquelético/efectos de la radiación , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento , Adulto Joven
2.
Radiother Oncol ; 131: 221-228, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30033384

RESUMEN

PURPOSE: To reduce arm morbidity, routine axillary lymph node dissection (ALND) is often omitted or replaced by axillary radiotherapy (AxRT) in patients with limited nodal involvement. We evaluated patient-reported arm morbidity and physical functioning in breast cancer patients undergoing modern-day axillary treatment. METHODS: All patients within the UMBRELLA cohort undergoing local radiotherapy with sentinel lymph node biopsy (SLNB), ALND and/or AxRT were selected. Patient-reported arm morbidity and physical functioning were assessed with EORTC QLQ C30/BR23 questionnaires up to eighteen months after initiation of radiotherapy. Patient-reported outcomes were compared between patients with SLNB only, ALND only, AxRT (level I-II), AxRT (level I-IV) or AxRT plus ALND by means of mixed model analysis. RESULTS: In total, 949 patients were identified; 641 (68%) SLNB only, 57 (6%) ALND only, 94 (10%) AxRT level I-II, 72 (8%) AxRT level I-IV and 85 (9%) ALND + AxRT. SLNB only resulted in the least arm morbidity scores. ALND + AxRT resulted in most arm morbidity, with clinically relevant differences at 18 months. AxRT (level I-II or level I-IV) resulted in significantly less arm symptoms in the first 3 months compared to ALND. Arm symptom scores between those receiving AxRT on levels I-II and I-IV were similar. CONCLUSION: Of all axillary management strategies, ALND plus AxRT is associated with worst patient-reported outcomes. AxRT resulted in less arm morbidity compared to ALND. Selective radiotherapy treatment of the axilla, i.e. radiotherapy of levels I-II only instead of levels I-IV, did not lead to clinically relevant reduced arm morbidity.


Asunto(s)
Brazo/fisiopatología , Brazo/efectos de la radiación , Neoplasias de la Mama/radioterapia , Neoplasias de la Mama/cirugía , Ganglios Linfáticos/efectos de la radiación , Ganglios Linfáticos/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Axila/efectos de la radiación , Axila/cirugía , Neoplasias de la Mama/patología , Neoplasias de la Mama/fisiopatología , Femenino , Humanos , Escisión del Ganglio Linfático , Ganglios Linfáticos/patología , Metástasis Linfática , Persona de Mediana Edad , Estadificación de Neoplasias , Medición de Resultados Informados por el Paciente , Biopsia del Ganglio Linfático Centinela , Encuestas y Cuestionarios
3.
Photochem Photobiol ; 94(6): 1289-1296, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-29878409

RESUMEN

Shade is an important means of protection against harmful effects of sun ultraviolet (UV) exposure, but not all shades are identically protective. UV rays scattered by the atmosphere and surroundings can reach the skin indirectly. To evaluate the relative contribution of the direct, diffuse, and reflected radiation in UV protection provided by different sizes of shade structure, we used SimUVEx v2, a numeric tool based on 3D graphic techniques and ambient ground UV irradiance. The relative UV exposure reduction was expressed by the predictive protection factor (PPF). Shade structures were found to predominantly reduce exposure from direct radiation (from 97.1% to 99.9% for the upper body areas such as the head and the neck), with greater protection from larger shade structures and structures closer above the subject. Legs were the least protected anatomical zone from any shade structure above the subject with PPF ranging from 18.5% to 68.1%. Throughout the day, except for lower solar zenith angles (SZA), small and high shade structures provide the lowest protection (between 20% and 50%), while small and low shade structure show PPF between 35% and 65% and large and high shade structures reach PPF higher than 60%.


Asunto(s)
Modelos Estadísticos , Dosis de Radiación , Piel/efectos de la radiación , Luz Solar/efectos adversos , Rayos Ultravioleta/efectos adversos , Brazo/efectos de la radiación , Simulación por Computador , Cabeza/efectos de la radiación , Humanos , Pierna/efectos de la radiación , Masculino , Maniquíes , Radiometría/estadística & datos numéricos , Dispersión de Radiación , Protectores Solares/análisis , Torso/efectos de la radiación
4.
J Am Coll Radiol ; 15(12): 1692-1697, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29724625

RESUMEN

OBJECTIVE: To compare the proportion of emergency department (ED) patients who undergo subsequent chest CT or MR within 1 year of an initially negative scan for pulmonary embolism (PE). METHODS: This single-center, retrospective, observational study examined the use of chest CT or MR for ED patients with MR angiography (MRA) negative for PE during April 2008 to March 2013. We compared the 1-year scan utilization for these cases to an age- and sex-matched cohort of patients who underwent CT angiography (CTA). We also calculated time to first follow-up scan and mean radiation dose in each arm. Trained data abstractors used a standardized protocol and electronic case report form to gather all outcomes of interest. Results are reported as means or proportions with their associated confidence intervals (CIs). RESULTS: In all, 717 ED patients (430 MRAs and 287 CTAs) were included. At 1 year, the proportion undergoing subsequent imaging (MRA 16.7%, CTA 15.3%; difference = 1.4%, 95% CI 4.05%-6.86%) and time to first follow-up scan (difference = 13 days, 95% CI -22.69-48.7) did not differ between arms. Mean radiation dose per patient at 1 year was significantly higher in the CTA arm (9.82 mSv; 95% CI 9.12-10.53) compared with 2.92 mSv (95% CI 1.86-3.98) with MRA. Those with an index MRA were more likely to undergo subsequent MRAs (odds ratio 3.68; 95% CI 1.22-11.12) than those with an index CTA. However, in both arms, the majority (85%) of subsequent scans were CTAs. CONCLUSIONS: When comparing patients initially undergoing MRA versus CTA for the evaluation of PE, there was no difference in downstream chest CT or MR use at 1 year.


Asunto(s)
Angiografía por Tomografía Computarizada , Angiografía por Resonancia Magnética , Embolia Pulmonar/diagnóstico por imagen , Adulto , Brazo/efectos de la radiación , Medios de Contraste , Servicio de Urgencia en Hospital , Femenino , Humanos , Masculino , Meglumina/análogos & derivados , Compuestos Organometálicos , Dosis de Radiación , Estudios Retrospectivos
5.
Radiother Oncol ; 126(1): 155-162, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29153463

RESUMEN

BACKGROUND AND PURPOSE: Adjuvant lymphatic radiotherapy (LNRT) is recommended for selected axillary node positive women with early breast cancer. We investigated whether hypofractionated LNRT is safe combined with similarly-hypofractionated breast/chest wall radiotherapy (RT). MATERIAL AND METHODS: The Standardisation of Breast Radiotherapy (START) pilot, A and B trials randomised women with early breast cancer to schedules of 2.67-3.3 Gy versus 2.0 Gy fractions (control). RT adverse effects were assessed by patients using the EORTC QLQ-BR23 and protocol-specific questions, and by physicians. Rates of arm/shoulder effects were compared between schedules for patients given LNRT. RESULTS: 864/5861 (14.7%) patients received LNRT (385 START-pilot, 318 START-A, 161 START-B). Prevalences of moderate/marked arm/shoulder effects were low up to 10 years. There were no significant differences between the hypofractionated and control groups for patient- and physician-assessed symptoms in START-A or START-B. In START-pilot, adverse effect rates were higher after 13 fractions of 3.3 Gy, consistent with effects reported in the breast/chest wall (significant for shoulder stiffness, HR 3.07, 95%CI 1.62-5.83, p = 0.001). CONCLUSIONS: The START trial results suggest that appropriately-dosed hypofractionated LNRT is safe in the long-term, according to patient and physician-assessed arm and shoulder symptoms. These findings are consistent with those reported after the same schedules delivered to the breast/chest wall.


Asunto(s)
Brazo/efectos de la radiación , Neoplasias de la Mama/radioterapia , Irradiación Linfática/efectos adversos , Traumatismos por Radiación/etiología , Hombro/efectos de la radiación , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Irradiación Linfática/métodos , Persona de Mediana Edad , Hipofraccionamiento de la Dosis de Radiación , Radioterapia Adyuvante , Reino Unido , Adulto Joven
6.
Biomed Res Int ; 2016: 1928540, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27247936

RESUMEN

Objective. Keratosis pilaris (KP) is a common condition which can frequently be cosmetically disturbing. Topical treatments can be used with limited efficacy. The objective of this study is to evaluate the effectiveness and safety of fractional carbon dioxide (CO2) laser for the treatment of KP. Patients and Methods. A prospective, randomized, single-blinded, intraindividual comparative study was conducted on adult patients with KP. A single session of fractional CO2 laser was performed to one side of arm whereas the contralateral side served as control. Patients were scheduled for follow-up at 4 and 12 weeks after treatment. Clinical improvement was graded subjectively by blinded dermatologists. Patients rated treatment satisfaction at the end of the study. Results. Twenty patients completed the study. All patients stated that the laser treatment improved KP lesions. At 12-week follow-up, 30% of lesions on the laser-treated side had moderate to good improvement according to physicians' global assessment (p = 0.02). Keratotic papules and hyperpigmentation appeared to respond better than the erythematous component. Four patients with Fitzpatrick skin type V developed transient pigmentary alteration. Conclusions. Fractional CO2 laser treatment may be offered to patients with KP. Dark-skinned patients should be treated with special caution.


Asunto(s)
Anomalías Múltiples/terapia , Brazo/efectos de la radiación , Enfermedad de Darier/terapia , Cejas/anomalías , Láseres de Gas/uso terapéutico , Piel/efectos de la radiación , Anomalías Múltiples/patología , Adulto , Brazo/patología , Enfermedad de Darier/patología , Cejas/patología , Femenino , Humanos , Masculino , Piel/patología , Resultado del Tratamiento
7.
Radiat Prot Dosimetry ; 164(3): 368-75, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25227436

RESUMEN

The purpose of this study was to evaluate the organ dose differences caused by the arms-raised and arms-lowered postures for multidetector computed tomography procedures. Organ doses were calculated using computational phantoms and Monte Carlo simulations. The arm position in two previously developed adult male and female human phantoms was adjusted to represent 'raised' and 'lowered' postures using advanced BREP-based mesh surface geometries. Organ doses from routine computed tomography (CT) scan protocols, including the chest, abdomen-pelvis, and chest-abdomen-pelvis scans, were simulated at various tube voltages and reported in the unit of mGy per 100 mAs. The CT scanner model was based on previously tested work. The differences in organ dose per unit tube current between raised and lowered arm postures were studied. Furthermore, the differences due to the tube current modulation (TCM) for these two different postures and their impact on organ doses were also investigated. For a given scan parameter, a patient having lowered arms received smaller doses to organs located within the chest, abdomen or pelvis when compared with the patient having raised arms. As expected, this is caused by the attenuation of the primary X rays by the arms. However, the skin doses and bone surface doses in the patient having lowered arms were found to be 3.97-32.12% larger than those in a patient having raised arms due to the fact that more skin and spongiosa were covered in the scan range when the arms are lowered. This study also found that dose differences become smaller with the increase in tube voltage for most of organs or tissues except the skin. For example, the liver dose differences decreased from -15.01 to -11.33% whereas the skin dose differences increased from 21.53 to 25.24% with tube voltage increased from 80 to 140 kVp. With TCM applied, the organ doses of all the listed organs in patient having lowered arms are larger due to the additional tube current necessary to overcome the presence of the arms while maintaining sufficient image quality Arm position affects the dose to internal organs from CT scans by as much as 25.3%. The presence of arms in the scan range results in a dose increase for the skin and bone surface, but a dose decrease for organs located in the torso. Considering the use of TCM, which is common in many clinics, the patient having lowered arms may receive 50% higher radiation dose to most of the organs because of the increased tube current. The use of higher tube voltage might narrow such dose differences between patients of these two postures due to the greater penetration of higher-energy X rays. Therefore, when calculating or reporting patient doses from CT scans, it is prudent to select an appropriate phantom that accurately represents the patient posture.


Asunto(s)
Brazo/efectos de la radiación , Simulación por Computador , Posicionamiento del Paciente , Fantasmas de Imagen , Monitoreo de Radiación , Tomógrafos Computarizados por Rayos X , Tomografía Computarizada por Rayos X/métodos , Adulto , Calibración , Femenino , Humanos , Masculino , Método de Montecarlo , Dosis de Radiación , Rayos X
8.
Breast Cancer Res Treat ; 135(1): 253-60, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22842984

RESUMEN

The randomized phase III trial TARGIT A showed non-inferiority regarding local control after intraoperative radiotherapy (IORT 20 Gy which was followed by whole breast radiotherapy (WBRT) in patients with risk factors only) in comparison to standard WBRT (50-56 Gy) after breast-conserving surgery in selected patients. This is the first analysis of long-term toxicities in the setting of TARGIT. Between 02/2002 and 12/2008, 305 patients were treated within TARGIT A (Arm A: n = 34 IORT, n = 20 IORT + WBRT for risk factors; Arm B WBRT: n = 55) or received IORT as a planned boost (control group: n = 196) at a single center. Toxicity was assessed according to the LENT SOMA scales. No significant differences were seen between Arm A and Arm B regarding fibrosis, breast edema, retraction, ulceration, lymphedema, hyperpigmentation, and pain. Arm A had significantly less telangiectases compared to Arm B (p = 0.049). In the subanalysis (Arm A IORT vs. Arm A IORT + WBRT vs. Arm B), fibrosis had a cumulative rate of 5.9 versus 37.5 versus 18.4 %, respectively (38.2 % IORT boost control group), at 3 years. No telangiectases were seen after IORT alone (0 % Arm A IORT vs. 17.5 % Arm A IORT + WBRT vs. 17.7 % Arm B). The hazard ratio of higher grade toxicity as first event was 0.46 (95 % CI, 0.26-0.83) for Arm A IORT as compared to Arm B (p = 0.010). No recurrences were seen after a median follow-up of 40 months (Arm A) and 42 months (Arm B). With its very low chronic skin toxicity rates and outstanding long-term results regarding toxicity and local control, IORT with 50 kV X-rays is a safe and effective method for treatment of selected breast cancer patients.


Asunto(s)
Neoplasias de la Mama/radioterapia , Neoplasias de la Mama/cirugía , Traumatismos por Radiación/etiología , Anciano , Anticuerpos Monoclonales Humanizados/uso terapéutico , Brazo/efectos de la radiación , Terapia Combinada , Femenino , Humanos , Periodo Intraoperatorio , Mastectomía Segmentaria , Persona de Mediana Edad , Tolerancia a Radiación , Dosificación Radioterapéutica , Tamoxifeno/uso terapéutico , Trastuzumab
9.
Lancet Oncol ; 11(3): 231-40, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20138809

RESUMEN

BACKGROUND: Few trials of adjuvant breast radiotherapy have incorporated patient-reported breast symptoms and related areas of quality of life. We assessed these measures in a quality-of-life study that was part of the randomised START (Standardisation of Breast Radiotherapy) trials. METHODS: In START trial A, 2236 patients were randomly assigned to receive either 39 Gy or 41.6 Gy delivered in 13 fractions over 5 weeks or a global standard of 50 Gy in 25 fractions. In START trial B, 2215 women were randomly assigned to receive either 40 Gy in 15 fractions over 3 weeks or the same control regimen (50 Gy in 25 fractions) as in trial A. 2739 patients were eligible for the quality-of-life study of whom 2208 (81%) were accrued (1129 patients from trial A and 1079 from trial B). Participants completed the EORTC QLQ-C30 and BR23 questionnaires and protocol-specific radiotherapy items up to 5 years after radiotherapy. We compared results across regimens with generalised estimating equations and survival analyses. The START trials are registered, ISRCTN59368779. FINDINGS: At 5 years, up to 40% women reported moderate or marked changes to the breast after radiotherapy, and arm and shoulder pain affected up to a third of patients. Breast symptoms and body image concerns reduced over time. Rates of radiotherapy adverse effects were lower for the 39 Gy regimen in trial A and the 40 Gy regimen in trial B, compared with the 50 Gy control regimen; rates of radiotherapy adverse effects were similar between the 41.6 Gy and 50 Gy regimens in trial A. Adverse change in skin appearance was significantly lower for patients who received 39 Gy compared with those who received 50 Gy (HR 0.63, 95% CI 0.47-0.84) and for those who received 40 Gy compared with those who received 50 Gy (0.76, 0.60-0.97); no significant difference was observed between patients who received 41.6 Gy and those who received 50 Gy in trial A (0.83, 0.63-1.08). Patient self-ratings of breast symptoms discriminated a 10% difference in randomised dose intensity. Up to a third of women reported moderate or marked pain in the arm and shoulder over 5 years whilst more than 10% experienced moderate or marked arm and hand swelling, with no significant difference in arm/shoulder subscale scores between the regimens in trial A or trial B; many baseline arm and shoulder symptoms were associated with prior surgery. INTERPRETATION: A substantial proportion of women report moderate or marked breast, arm, and shoulder symptoms over 5 years of follow-up after radiotherapy, but with no detriment to body image. Nonetheless, most patients stand to gain from hypofractionated radiotherapy regimens with a potential for fewer adverse effects; this strengthens the evidence from the START trials for hypofractionated regimens for women requiring radiotherapy for early breast cancer. FUNDING: Cancer Research UK, UK Medical Research Council, UK Department of Health.


Asunto(s)
Imagen Corporal , Neoplasias de la Mama/radioterapia , Calidad de Vida , Traumatismos por Radiación/epidemiología , Piel/efectos de la radiación , Brazo/efectos de la radiación , Mama/efectos de la radiación , Neoplasias de la Mama/psicología , Neoplasias de la Mama/cirugía , Relación Dosis-Respuesta en la Radiación , Femenino , Estudios de Seguimiento , Humanos , Mastectomía Radical , Mastectomía Segmentaria , Persona de Mediana Edad , Dosis de Radiación , Traumatismos por Radiación/psicología , Radioterapia/efectos adversos , Radioterapia/métodos , Radioterapia Adyuvante/efectos adversos , Hombro/efectos de la radiación , Análisis de Supervivencia , Reino Unido/epidemiología
10.
Photochem Photobiol Sci ; 8(8): 1195-201, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19639123

RESUMEN

Measurements of anatomical UV exposure distribution were made using miniaturized polysulfone dosimeters over a four year period between 2005 and 2008 in Toowoomba, Australia (28 degrees S, 152 degrees E). Anatomical UV exposures were expressed relative to the horizontal plane ambient UV. The UV exposures were compared with existing data detailing the anatomical distribution of basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and solar keratoses (SK). Surface UV exposures to unprotected skin surfaces have been presented for each of the face, neck, arm, hand and leg assessing a total of 1453 body sites (2491 measurements). Measured exposures are presented for the human facial region to a resolution of 5 mm. The median anatomical UV expressed relative to the horizontal plane ambient UV for each of the face, neck, forearm, hand and leg regions of the body varied from 26%, 23%, 13%, 30% and 12% respectively in the 0 degrees-30 degrees SZA range; 39%, 36%, 17%, 35% and 23% in the 30 degrees-50 degrees SZA range; and 48%, 59%, 41%, 42% and 47% in the 50 degrees-80 degrees SZA range. Detailed positions of UV exposure measured over the face, neck, arm, hand and leg were more closely related to NMSC incidence data for the face and upper limbs. Further analysis with existing facial BCC and SK density data did not however show a direct relationship with the measured UV exposures highlighting the importance of other factors influencing the causation and localisation of facial NMSC.


Asunto(s)
Carcinoma Basocelular/epidemiología , Carcinoma de Células Escamosas/epidemiología , Queratosis/epidemiología , Piel/patología , Rayos Ultravioleta , Brazo/patología , Brazo/efectos de la radiación , Australia/epidemiología , Relación Dosis-Respuesta en la Radiación , Exposición a Riesgos Ambientales , Cara/patología , Cara/efectos de la radiación , Mano/patología , Mano/efectos de la radiación , Humanos , Incidencia , Pierna/patología , Pierna/efectos de la radiación , Cuello/patología , Cuello/efectos de la radiación , Piel/efectos de la radiación
11.
Health Phys ; 96(5): 594-601, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19359853

RESUMEN

This paper describes the development of a software package, called VR Dose Simulator, which aims to provide interactive radiation safety and ALARA training to radiation workers using virtual-reality (VR) simulations. Combined with a pre-calculated effective dose equivalent (EDE) database, a virtual radiation environment was constructed in VR authoring software, EON Studio, using 3-D models of a real nuclear power plant building. Models of avatars representing two workers were adopted with arms and legs of the avatar being controlled in the software to simulate walking and other postures. Collision detection algorithms were developed for various parts of the 3-D power plant building and avatars to confine the avatars to certain regions of the virtual environment. Ten different camera viewpoints were assigned to conveniently cover the entire virtual scenery in different viewing angles. A user can control the avatar to carry out radiological engineering tasks using two modes of avatar navigation. A user can also specify two types of radiation source: Cs and Co. The location of the avatar inside the virtual environment during the course of the avatar's movement is linked to the EDE database. The accumulative dose is calculated and displayed on the screen in real-time. Based on the final accumulated dose and the completion status of all virtual tasks, a score is given to evaluate the performance of the user. The paper concludes that VR-based simulation technologies are interactive and engaging, thus potentially useful in improving the quality of radiation safety training. The paper also summarizes several challenges: more streamlined data conversion, realistic avatar movement and posture, more intuitive implementation of the data communication between EON Studio and VB.NET, and more versatile utilization of EDE data such as a source near the body, etc., all of which needs to be addressed in future efforts to develop this type of software.


Asunto(s)
Exposición a Riesgos Ambientales , Dosis de Radiación , Monitoreo de Radiación/métodos , Prueba de Realidad , Programas Informáticos , Interfaz Usuario-Computador , Brazo/efectos de la radiación , Simulación por Computador , Femenino , Humanos , Pierna/efectos de la radiación , Masculino , Plantas de Energía Nuclear , Postura
12.
Diabetologia ; 52(5): 789-97, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19274450

RESUMEN

AIMS/HYPOTHESIS: The UK Prospective Diabetes Study (UKPDS) risk engine has become a standard for cardiovascular risk assessment in type 2 diabetes mellitus. Skin autofluorescence was recently introduced as an alternative tool for cardiovascular risk assessment in diabetes. We investigated the prognostic value of skin autofluorescence for cardiovascular events in combination with the UKPDS risk engine in a cohort of patients with type 2 diabetes managed in primary care. METHODS: Clinical, UKPDS risk engine and skin autofluorescence data were obtained at baseline in 2001-2002 in the type 2 diabetes group (n = 973). Follow-up data concerning fatal and non-fatal cardiovascular events (primary endpoint) were obtained till 2005. Patients were classified as 'low risk' when their 10 year UKPDS risk score for fatal cardiovascular events was <10%, and 'high risk' if >10%. Skin autofluorescence was measured non-invasively with an autofluorescence reader. Skin autofluorescence was classified by the median (i.e. low risk < median, high risk > median). RESULTS: The incidence of cardiovascular events was 119 (44 fatal, 75 non-fatal). In multivariate analysis, skin autofluorescence, age, sex and diabetes duration were predictors for the primary endpoint. Addition of skin autofluorescence information to that from the UKPDS risk engine resulted in re-classification of 55 of 203 patients from the low-risk to the high-risk group. The 10 year cardiovascular event rate was higher in patients with a UKPDS score >10% when skin autofluorescence was above the median (55.8% vs 38.9%). CONCLUSIONS/INTERPRETATION: Skin autofluorescence provides additional information to the UKPDS risk engine which can result in risk re-classification of a substantial number of patients. It furthermore identifies patients who have a particularly high risk for developing cardiovascular events.


Asunto(s)
Enfermedades Cardiovasculares/epidemiología , Diabetes Mellitus Tipo 2/patología , Angiopatías Diabéticas/epidemiología , Piel/efectos de la radiación , Anciano , Análisis de Varianza , Brazo/efectos de la radiación , Presión Sanguínea , Enfermedades Cardiovasculares/mortalidad , Estudios de Cohortes , Diabetes Mellitus Tipo 2/complicaciones , Femenino , Fluorescencia , Hemoglobina Glucada/metabolismo , Productos Finales de Glicación Avanzada/metabolismo , Humanos , Luz , Masculino , Persona de Mediana Edad , Análisis Multivariante , Médicos de Familia , Pronóstico , Medición de Riesgo , Reino Unido
13.
Radiat Prot Dosimetry ; 115(1-4): 548-52, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16381783

RESUMEN

In nuclear medicine departments, where radioactive sources are manipulated, the personnel can receive large radiation doses to the skin of their hands. For performing detailed characterisations and dose optimisations of these workplaces, active extremity dosemeters can be used as complementary tools to passive hand monitoring. Active extremity dosimetry is still a subject of research. In this context, IRSN has started a research and development programme. As a first step, a hospital workplace study has been performed using thermoluminescence dosemeters and has shown, in agreement with previous works, that the pads of the fingers, points that are very difficult to instrument, receive the largest doses. Numerical studies have now started, with the aim of calculating the dose equivalent gradients through the hands, in order to optimise the locations of the detectors.


Asunto(s)
Brazo/fisiología , Modelos Biológicos , Exposición Profesional/análisis , Monitoreo de Radiación/instrumentación , Monitoreo de Radiación/métodos , Protección Radiológica/instrumentación , Protección Radiológica/métodos , Brazo/efectos de la radiación , Estudios de Factibilidad , Humanos , Modelos Estadísticos , Método de Montecarlo , Personal de Hospital , Dosis de Radiación , Medición de Riesgo/métodos , Factores de Riesgo , Piel/efectos de la radiación , Fenómenos Fisiológicos de la Piel
14.
J Neurophysiol ; 94(6): 4209-23, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16120657

RESUMEN

Electrical stimulation of the motor cortex in monkeys can evoke complex, multijoint movements including movements of the arm and hand. In this study, we examined these movements in detail and tested whether they showed adaptability to differing circumstances such as to a weight added to the hand. Electrical microstimulation was applied to motor cortex using pulse trains of 500-ms duration (matching the approximate duration of a reach). Arm movement was measured using a high-resolution three-dimensional tracking system. Movement latencies averaged 80.2 ms. Speed profiles were typically smooth and bell-shaped, and the peak speed covaried with movement distance. Stimulation generally evoked a specific final hand position. The convergence of the hand from disparate starting positions to a narrow range of final positions was statistically significant for every site tested (91/91). When a weight was fixed to the hand, for some stimulation sites (74%), the evoked movement appeared to compensate for the weight in that the hand was lifted to a similar final location. For other stimulation sites (26%), the weight caused a significant reduction in final hand height. For about one-half of the sites (54%), the variation in movement of each joint appeared to compensate for the variation in the other joints in a manner that stabilized the hand in a restricted region of space. These findings suggest that at least some of the stimulation-evoked movements reflect relatively high-level, adaptable motor plans.


Asunto(s)
Brazo/inervación , Brazo/efectos de la radiación , Estimulación Eléctrica , Corteza Motora/efectos de la radiación , Movimiento/efectos de la radiación , Potenciales de Acción/fisiología , Potenciales de Acción/efectos de la radiación , Animales , Conducta Animal , Mapeo Encefálico , Relación Dosis-Respuesta en la Radiación , Mano/fisiología , Mano/efectos de la radiación , Macaca fascicularis , Masculino , Corteza Motora/citología , Neuronas/fisiología , Neuronas/efectos de la radiación , Tiempo de Reacción
15.
Spine (Phila Pa 1976) ; 30(16): 1893-8, 2005 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-16103862

RESUMEN

STUDY DESIGN: A prospective case control study design was conducted. OBJECTIVES: The purpose of the current study was to determine the intraoperative radiation hazard to spine surgeons by occupational radiation exposure during percutaneous vertebroplasty and possible consequences with respect to radiation protection. SUMMARY OF BACKGROUND DATA: The development of minimally invasive surgery techniques has led to an increasing number of fluoroscopically guided procedures being done percutaneously such as vertebroplasty, which is the percutaneous cement augmentation of vertebral bodies. METHODS: Three months of occupational dose data for two spine surgeons was evaluated measuring the radiation doses to the thyroid gland, the upper extremities, and the eyes during vertebroplasty. RESULTS: The annual risk of developing a fatal cancer of the thyroid is 0.0025%, which means a very small to small risk. The annual morbidity (the risk of developing a cancer including nonfatal ones) is 0.025%, which already means a small to medium risk. The dose for the eye lens was about 8% of the threshold dose to develop a radiation induced cataract (150 mSv); therefore, the risk is very low but not negligible. The doses measured for the skin are 10% of the annual effective dose limit (500 mSv) recommended by the ICRP (International Commission on Radiologic Protection); therefore, the annual risk for developing a fatal skin cancer is very low. CONCLUSION: While performing percutaneous vertebroplasty, the surgeon is exposed to a significant amount of radiation. Proper surgical technique and shielding devices to decrease potentially high morbidity are mandatory. Training in radiation protection should be an integral part of the education for all surgeons using minimally invasive radiologic-guided interventional techniques.


Asunto(s)
Fluoroscopía , Exposición Profesional , Procedimientos Ortopédicos , Médicos , Radiación , Columna Vertebral/cirugía , Cirugía Asistida por Computador , Anciano , Anciano de 80 o más Años , Brazo/efectos de la radiación , Estudios de Casos y Controles , Catarata/etiología , Ojo/efectos de la radiación , Femenino , Fluoroscopía/efectos adversos , Humanos , Periodo Intraoperatorio , Masculino , Procedimientos Quirúrgicos Mínimamente Invasivos , Neoplasias Inducidas por Radiación/etiología , Estudios Prospectivos , Dosis de Radiación , Medición de Riesgo , Neoplasias Cutáneas/etiología , Glándula Tiroides/efectos de la radiación , Neoplasias de la Tiroides/etiología
16.
Bioelectromagnetics ; 26(5): 357-66, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15887251

RESUMEN

The goal of this study was to address some of the factors that contribute to the human ability to detect the presence of weak electric fields generated by direct current (DC) and alternating current (AC) sources. An exposure chamber allowed us to expose a limited surface of the body (forearm and hand) to DC fields of up to 65 kV/m and AC fields up to a maximum of 35 kV/m (frequency 60 Hz). Perception was examined using a staircase procedure and a rating procedure derived from signal detection theory. Sixteen subjects participated in the experiments, and none detected the local DC fields. In contrast, 9/16 subjects were sensitive to local AC electric fields, although detection thresholds (index of sensitivity, d' = 1.0) were widely variable between subjects. When regional exposure was limited to the dorsal forearm, performance was similar to that seen when the forearm and hand were exposed. In contrast, subjects did not reliably detect the AC electric fields when exposure was limited to the hand (either hairy or glabrous skin), although a minority of subjects (3/9) showed some evidence of detecting fields presented to the glabrous palm. Subjects were unable to detect AC electric fields when the hair was removed from the forearm and hand, suggesting that the evoked sensation is mainly dependent on movement of hair located in the exposed region.


Asunto(s)
Brazo/fisiología , Umbral Diferencial/fisiología , Estimulación Eléctrica/métodos , Campos Electromagnéticos , Cabello/fisiología , Sensación/fisiología , Adulto , Brazo/efectos de la radiación , Umbral Diferencial/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Femenino , Cabello/efectos de la radiación , Humanos , Masculino , Percepción/fisiología , Percepción/efectos de la radiación , Dosis de Radiación , Sensación/efectos de la radiación
17.
J Neurol Sci ; 223(2): 121-7, 2004 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-15337612

RESUMEN

Debate persists about the effectiveness of poststroke behavioral interventions for progress toward motor recovery. The current meta-analysis assessed the effect of electromyogram (EMG)-triggered neuromuscular stimulation on arm and hand functions. Computer searches of PubMed and Cochran databases, as well as hand searches of reference lists identified seven EMG-triggered neuromuscular stimulation studies. Outcome measures focused on arm and hand motor capability functions. In addition, the quality of each study was rated on three guidelines: randomization, double blind, and dropouts. After adjusting data for consistency in the arm/hand outcome measures and to avoid bias, five active stimulation studies were included in the analysis. Rehabilitation treatment in each study focused on wrist extension. The total number of individuals in the treatment groups was 47 whereas the control groups had 39 subjects. The meta-analysis revealed a significant overall mean effect size (delta=0.82, S.D.=0.59). A homogeneity test indicated that the pooled standardized effect sizes estimated the same treatment effect. A fail-safe test for null effect findings revealed that 15 studies were required to reduce the large effect (0.82) to a small effect (0.20). These improved wrist extension motor capabilities findings support EMG-triggered neuromuscular stimulation as an effective poststroke protocol.


Asunto(s)
Estimulación Eléctrica , Actividad Motora/efectos de la radiación , Unión Neuromuscular/efectos de la radiación , Recuperación de la Función/efectos de la radiación , Rehabilitación de Accidente Cerebrovascular , Brazo/fisiopatología , Brazo/efectos de la radiación , Método Doble Ciego , Electromiografía/métodos , Mano/fisiopatología , Mano/efectos de la radiación , Humanos , Actividad Motora/fisiología , Unión Neuromuscular/fisiopatología , PubMed/estadística & datos numéricos , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Recuperación de la Función/fisiología , Accidente Cerebrovascular/fisiopatología , Resultado del Tratamiento
18.
J Opt Soc Am A Opt Image Sci Vis ; 20(12): 2347-54, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14686514

RESUMEN

We present, to our knowledge for the first time, results of ultrasound-modulated light signals on living tissues. In particular, we analyze, both theoretically and experimentally, the effect of speckle fluctuations on the signal. We find that two different kinds of noise compete--shot noise and speckle noise--and are present at different levels in static phantoms and ex vivo tissue samples on the one hand and in dynamic phantoms and living tissues on the other hand.


Asunto(s)
Luz , Ultrasonido , Animales , Brazo/diagnóstico por imagen , Brazo/efectos de la radiación , Artefactos , Miembro Anterior/diagnóstico por imagen , Miembro Anterior/efectos de la radiación , Humanos , Ratones , Modelos Biológicos , Fantasmas de Imagen , Ultrasonografía
19.
Radiat Prot Dosimetry ; 95(2): 177-9, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11572647

RESUMEN

Calculations are presented of the specific energy absorption rate, SAR, in the lower arm of the NRPB anatomically realistic voxel model. NORMAN, for induced currents from 100 kHz to 80 MHz. The wrist region has a narrow cross section and contains little high conductivity muscle, comprising mainly low conductivity bone, tendon and fat. Consequently there is a channelling of the current through the high conductivity muscle, which produces high, localised values of the SAR. Values averaged over 10 g and 100 g of tissue are calculated as a function of the current flowing through the wrist.


Asunto(s)
Brazo/efectos de la radiación , Radiometría/métodos , Muñeca/efectos de la radiación , Absorción , Campos Electromagnéticos , Humanos , Modelos Anatómicos , Especificidad de Órganos , Fantasmas de Imagen , Dosis de Radiación
20.
Exp Brain Res ; 139(2): 168-72, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11497058

RESUMEN

ract This study aimed to evaluate whether painful cutaneous stimuli can affect specifically the excitability of the arm proximal muscle motor area. The motor evoked potentials (MEPs), recorded from the right biceps brachii muscle after either transcranial magnetic or electrical anodal stimulation of the left primary motor (MI) cortex, were conditioned by painful CO2 laser stimuli delivered either on the right hand dorsum or on the lateral surface of the right arm. Painful CO2 laser stimuli delivered on the hand skin reduced significantly the amplitude of MEPs evoked by the transcranial magnetic stimulation of the contralateral MI area, while the MEP amplitude was not significantly modified by CO2 laser pulses delivered on the arm skin. The inhibitory effect followed the arrival of the nociceptive inputs to the cerebral cortex. The amplitude of MEPs evoked by anodal electrical stimulation of the motor cortex was not decreased by conditioning painful stimuli delivered on the hand dorsum. Since the magnetic stimulation led to transynaptic activation of pyramidal neurons, while the anodal stimulation activated directly corticospinal axons, our findings suggest that CO2 laser pulses delivered on the hand are able to inhibit the arm proximal muscle motor area.


Asunto(s)
Brazo , Encéfalo/fisiopatología , Calor , Músculo Esquelético/fisiopatología , Inhibición Neural/fisiología , Dolor/fisiopatología , Adulto , Brazo/efectos de la radiación , Condicionamiento Psicológico , Potenciales Evocados Motores/fisiología , Femenino , Mano/efectos de la radiación , Humanos , Rayos Láser , Masculino
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA