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1.
Burns ; 44(5): 1317-1321, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29602716

RESUMEN

INTRODUCTION: Campfire burns in children are a significant health issue. It is imperative that the extent of the problem is examined and strategies discussed to inform future prevention campaigns. METHOD: A retrospective review of data from the Queensland Paediatric Burns Registry for all children presenting with campfire burns between January 2013 and December 2014 (inclusive). Information collected included patient demographics, detail regarding mechanism of injury, first aid, Total Body Surface Area (TBSA), burn depth, and treatment. RESULTS: Seventy-five children with campfire burns were seen in our paediatric burns centre during this 2-year period. The median age of patients was 3 years (range 10 days-14 years). The hands and feet were the areas most commonly affected. Eleven percent of patients suffered flame burns, whilst 89% suffered contact burns from the hot coals or ashes. Of the latter group, approximately half experienced burns from campfires that had been extinguished for at least one night. Thirteen percent of patients underwent split thickness skin grafting. The incidence of burns was increased during school holiday months. DISCUSSION: We have previously demonstrated the effectiveness of targeted campaigns in reducing the incidence of campfire burns. A significant portion of patients sustained burns from incorrectly extinguished campfires. These injuries are likely to be preventable with ongoing public awareness campaigns.


Asunto(s)
Quemaduras/epidemiología , Acampada , Incendios , Primeros Auxilios , Sistema de Registros , Trasplante de Piel , Adolescente , Superficie Corporal , Unidades de Quemados , Quemaduras/terapia , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Queensland/epidemiología , Estudios Retrospectivos
2.
Rev Sci Instrum ; 88(8): 083503, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28863637

RESUMEN

We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

3.
Burns ; 43(4): 724-732, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28408145

RESUMEN

BACKGROUND: Partial thickness burns of up to 10% total body surface area (TBSA) in children are common injuries primarily treated in the outpatient setting using expensive silver-containing dressings. However, economic evaluations in the paediatric burns population are lacking to assist healthcare providers when choosing which dressing to use. The aim of this study was to conduct a cost-effectiveness analysis of three silver dressings for partial thickness burns ≤10% TBSA in children aged 0-15 years using days to full wound re-epithelialization as the health outcome. METHOD: This study was a trial based economic evaluation (incremental cost effectiveness) conducted from a healthcare provider perspective. Ninety-six children participated in the trial investigating Acticoat™, Acticoat™ with Mepitel™ or Mepilex Ag™. Costs directly related to the management of partial thickness burns ≤10% TBSA were collected during the trial from March 2013 to July 2014 and for a one year after re-epithelialization time horizon. Incremental cost effectiveness ratios were estimated and dominance probabilities calculated from bootstrap resampling trial data. Sensitivity analyses were conducted to examine the potential effect of accounting for infrequent, but high cost, skin grafting surgical procedures. RESULTS: Costs (dressing, labour, analgesics, scar management) were considerably lower in the Mepilex Ag™ group (median AUD$94.45) compared to the Acticoat™ (median $244.90) and Acticoat™ with Mepitel™ (median $196.66) interventions. There was a 99% and 97% probability that Mepilex Ag™ dominated (cheaper and more effective than) Acticoat™ and Acticoat™ with Mepitel™, respectively. This pattern of dominance was consistent across raw cost and effects, after a priori adjustments, and sensitivity analyses. There was an 82% probability that Acticoat™ with Mepitel dominated Acticoat™ in the primary analysis, although this probability was sensitive to the effect of skin graft procedures. CONCLUSION: This economic evaluation has demonstrated that Mepilex Ag™ was the dominant dressing choice over both Acticoat™ and Acticoat™ with Mepitel™ in this trial-based economic evaluation and is recommended for treatment of paediatric partial thickness burns ≤10% TBSA.


Asunto(s)
Vendajes/economía , Quemaduras/economía , Poliésteres/economía , Polietilenos/economía , Siliconas/economía , Compuestos de Plata/economía , Adolescente , Australia , Superficie Corporal , Quemaduras/patología , Quemaduras/terapia , Niño , Preescolar , Análisis Costo-Beneficio , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Repitelización , Compuestos de Plata/uso terapéutico , Índices de Gravedad del Trauma
4.
Burns ; 42(1): 97-103, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26546385

RESUMEN

INTRODUCTION: There is a paucity of research investigating the scar outcome of children with partial thickness burns. The aim of this study was to assess the scar outcome of children with partial thickness burns who received a silver dressing acutely. METHOD: Children aged 0-15 years with an acute partial thickness burn, ≤10% TBSA were included. Children were originally recruited for an RCT investigating three dressings for partial thickness burns. Children were assessed at 3 and 6 months after re-epithelialization. 3D photographs were taken of the burn site, POSAS was completed and skin thickness was measured using ultrasound imaging. RESULTS: Forty-three children returned for 3 and 6 month follow-ups or returned a photo. Days to re-epithelialization was a significant predictor of skin/scar quality at 3 and 6 months (p<0.01). Patient-rated color and observer-rated vascularity and pigmentation POSAS scores were comparable at 3 months (color vs. vascularity 0.88, p<0.001; color vs. pigmentation 0.64, p<0.001), but patients scored higher than the observer at 6 months (color vs. vascularity 0.57, p<0.05; color vs. pigmentation 0.15, p=0.60). Burn depth was significantly correlated with skin thickness (r=0.51, p<0.01). Hypopigmentation of the burn site was present in 25.8% of children who re-epithelialized in ≤ 2 weeks. CONCLUSION: This study has provided information on outcomes for children with partial thickness burns and highlighted a need for further education of this population.


Asunto(s)
Vendajes , Quemaduras/terapia , Cicatriz/patología , Hipopigmentación/patología , Repitelización/fisiología , Compuestos de Plata/uso terapéutico , Adolescente , Quemaduras/complicaciones , Quemaduras/diagnóstico por imagen , Niño , Preescolar , Cicatriz/etiología , Femenino , Estudios de Seguimiento , Humanos , Hipopigmentación/etiología , Lactante , Recién Nacido , Masculino , Fotograbar , Poliésteres/uso terapéutico , Polietilenos/uso terapéutico , Siliconas/uso terapéutico , Cicatrización de Heridas/fisiología
5.
Burns ; 41(5): 946-55, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25687836

RESUMEN

BACKGROUND: This study compared the effects of three silver dressing combinations on small to medium size acute partial thickness burns in children, focusing on re-epithelialization time, pain and distress during dressing changes. METHOD: Children (0-15 years) with clean, ≤ 10% total body surface area (TBSA) partial thickness burns who met the inclusion criteria were included in the study. Children received either (1) Acticoat™; (2) Acticoat™ with Mepitel™; or (3) Mepilex Ag™ dressings. Measures of burn re-epithelialization, pain, and distress were recorded at dressing changes every 3-5 days until full re-epithelialization occurred. RESULTS: One hundred and three children were recruited with 96 children included for analysis. No infections were detected for the course of the study. When adjusted for burn depth, Acticoat™ significantly increased the expected days to full re-epithelialization by 40% (IRR = 1.40; 95% CI: 1.14-1.73, p < 0.01) and Acticoat™ with Mepitel™ significantly increased the expected days to full re-epithelialization by 33% (IRR = 1.33; 95% CI: 1.08-1.63, p ≤ 0.01) when compared to Mepilex Ag™. Expected FLACC scores in the Mepilex Ag™ group were 32% lower at dressing removal (p = 0.01) and 37% lower at new dressing application (p = 0.04); and scores in the Acticoat™ with Mepitel™ group were 23% lower at dressing removal (p = 0.04) and 40% lower at new dressing application (p < 0.01), in comparison to the Acticoat™ group. Expected Visual Analog Scale-Pain (VAS-P) scores were 25% lower in the Mepilex Ag™ group at dressing removal (p = 0.04) and 34% lower in the Acticoat™ with Mepitel™ group (p = 0.02) at new dressing application in comparison to the Acticoat™ group. There was no significant difference between the Mepilex Ag™ and the Acticoat™ with Mepitel™ groups at all timepoints and with any pain measure. CONCLUSION: Mepilex Ag™ is an effective silver dressing, in terms of accelerated wound re-epithelialization time (compared to Acticoat™ and Acticoat™ with Mepitel™) and decreased pain during dressing changes (compared to Acticoat™), for clean, < 10% TBSA partial thickness burns in children.


Asunto(s)
Quemaduras/terapia , Apósitos Oclusivos , Poliésteres/uso terapéutico , Polietilenos/uso terapéutico , Repitelización , Siliconas/uso terapéutico , Adolescente , Vendajes , Quemaduras/patología , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Dolor , Dimensión del Dolor , Análisis de Regresión , Método Simple Ciego , Factores de Tiempo , Resultado del Tratamiento , Cicatrización de Heridas
6.
Burns ; 41(6): 1286-90, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25716762

RESUMEN

BACKGROUND: Reliability and validity of 3D photography (3D LifeViz™ System) compared to digital planimetry (Visitrak™) has been established in a compliant cohort of children with acute burns. Further research is required to investigate these assessment tools in children representative of the general pediatric burns population, specifically children under the age of three years. AIM: To determine if 3D photography is a reliable wound assessment tool compared to Visitrak™ in children of all ages with acute burns ≤10% TBSA. METHOD: Ninety-six children (median age 1 year 9 months) who presented to the Royal Children's Hospital Brisbane with an acute burn ≤10% TBSA were recruited into the study. Wounds were measured at the first dressing change using the Visitrak™ system and 3D photography. All measurements were completed by one investigator and level of agreement between wound surface area measurements was calculated. RESULTS: Wound surface area measurements were complete (i.e. participants had measurements from both techniques) for 75 participants. Level of agreement between wound surface area measurements calculated using an intra-class correlation coefficient (ICC) was excellent (ICC 0.96, 95% CI 0.93, 0.97). Visitrak™ tracings could not be completed in 19 participants with 16 aged less than two years. 3D photography could not be completed for one participant. Barriers to completing tracings were: excessive movement, pain, young age or wound location (e.g. face or perineum). CONCLUSION: This study has confirmed 3D photography as a reliable alternative to digital planimetry in children of all ages with acute burns ≤10% TBSA. In addition, 3D photography is more suitable for very young children given its non-invasive nature.


Asunto(s)
Superficie Corporal , Quemaduras/diagnóstico , Imagenología Tridimensional/métodos , Fotogrametría/métodos , Adolescente , Quemaduras/patología , Niño , Preescolar , Estudios de Cohortes , Femenino , Humanos , Lactante , Masculino , Fotograbar/métodos , Reproducibilidad de los Resultados
7.
Burns ; 41(4): 708-13, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25703661

RESUMEN

AIM AND METHOD: The aim of this study was to determine the reasons why children with burns are admitted upon primary presentation to a tertiary burns centre. The study was a retrospective chart review of all children admitted to the Stuart Pegg Paediatric Burns Centre with a burns injury over an 18 month period. RESULTS: A total of 159 children with an overall median age of 25 months were included in the study. The reason for admission was able to be determined in all but two of these patients, and categorised into either severity, region of body burnt, social reasons, timing of presentation, geographical reasons, age and other. The majority of children (45%) were admitted for severity, followed by region of body burnt (24%) and social reasons (11%). One third of children were admitted because of reasons other than the biology of the burn itself (severity or body region). CONCLUSION: The findings of this study demonstrate that it is not just children with severe burns who are admitted. One third of children are admitted because of the impact of the burn injury on the family, not because of a need for immediate management of the burns injury itself. The full impact of paediatric burns on our healthcare system is not solely determined by the physical characteristics of the burn itself.


Asunto(s)
Unidades de Quemados/estadística & datos numéricos , Quemaduras/patología , Hospitalización/estadística & datos numéricos , Centros de Atención Terciaria/estadística & datos numéricos , Adolescente , Factores de Edad , Niño , Preescolar , Estudios de Cohortes , Femenino , Geografía , Humanos , Lactante , Recién Nacido , Tiempo de Internación , Masculino , Queensland , Estudios Retrospectivos , Medio Social , Factores de Tiempo , Índices de Gravedad del Trauma
8.
Burns ; 41(3): 476-83, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25451145

RESUMEN

AIM AND METHOD: The aim of this study was to describe the mechanism of injury and outcome of all children who presented to The Stuart Pegg Paediatric Burns Centre (SPPBC) with a burn injury in the year 2013. A detailed proforma was completed prospectively at time of presentation to hospital. RESULTS: During the one year period, 758 children with a median age of 2 years 3 months presented with a burn injury. Overall, 12.7% of patients (n=96) were initially treated as inpatients. Similarities existed between in and outpatients. Over half the children admitted had a scald injury (53.1%). Whilst slightly higher than the outpatient scald rate of 43.1% there was no statistical significant difference. However, there was a significant difference between inpatients and outpatients with respect to other mechanisms of injury. Contact burns were under represented in inpatients (27.1%) compared to outpatients (44.5%), p<0.05. In contrast, flame burns were over represented in inpatients, 11.5% compared to outpatients, 2.9% (p<0.05). CONCLUSION: Paediatric burns are a common cause of childhood injury. The majority of children present with small to medium sized partial thickness injuries and are managed as outpatients. In order to understand the true impact of paediatric burn injury and to develop appropriate targeted injury prevention campaigns, data repositories must include detailed information regarding outpatient paediatric burns.


Asunto(s)
Atención Ambulatoria/estadística & datos numéricos , Unidades de Quemados , Quemaduras/epidemiología , Traumatismos de la Mano/epidemiología , Hospitalización/estadística & datos numéricos , Adolescente , Distribución por Edad , Quemaduras/etiología , Quemaduras/terapia , Niño , Preescolar , Estudios de Cohortes , Femenino , Traumatismos de la Mano/etiología , Traumatismos de la Mano/terapia , Humanos , Lactante , Recién Nacido , Masculino , Estudios Prospectivos , Queensland/epidemiología , Distribución por Sexo , Trasplante de Piel , Factores de Tiempo
9.
Burns ; 41(1): 80-4, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24877886

RESUMEN

BACKGROUND: In the paediatric population careful attention needs to be made concerning techniques utilised for wound assessment to minimise discomfort and stress to the child. AIM: To investigate whether 3D photography is a valid measure of burn wound area in children compared to the current clinical gold standard method of digital planimetry using Visitrak™. METHOD: Twenty-five children presenting to the Stuart Pegg Paediatric Burn Centre for burn dressing change following acute burn injury were included in the study. Burn wound area measurement was undertaken using both digital planimetry (Visitrak™ system) and 3D camera analysis. Inter-rater reliability of the 3D camera software was determined by three investigators independently assessing the burn wound area. RESULTS: A comparison of wound area was assessed using intraclass correlation co-efficients (ICC) which demonstrated excellent agreement 0.994 (CI 0.986, 0.997). Inter-rater reliability measured using ICC 0.989 (95% CI 0.979, 0.995) demonstrated excellent inter-rater reliability. Time taken to map the wound was significantly quicker using the camera at bedside compared to Visitrak™ 14.68 (7.00)s versus 36.84 (23.51)s (p<0.001). In contrast, analysing wound area was significantly quicker using the Visitrak™ tablet compared to Dermapix(®) software for the 3D Images 31.36 (19.67)s versus 179.48 (56.86)s (p<0.001). CONCLUSION: This study demonstrates that images taken with the 3D LifeViz™ camera and assessed with Dermapix(®) software is a reliable method for wound area assessment in the acute paediatric burn setting.


Asunto(s)
Superficie Corporal , Quemaduras/diagnóstico , Imagenología Tridimensional/métodos , Fotograbar/métodos , Quemaduras/patología , Niño , Preescolar , Estudios de Cohortes , Femenino , Humanos , Lactante , Masculino , Variaciones Dependientes del Observador , Estudios Prospectivos , Reproducibilidad de los Resultados , Programas Informáticos
10.
Int J Tuberc Lung Dis ; 16(5): 665-9, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22410400

RESUMEN

SETTING: In 2005, tuberculin skin test conversions were observed following exposure to a patient with active pulmonary tuberculosis (TB) who recovered post-bronchoscopy in an open area at The Ottawa Hospital, Canada. In response, we implemented a screening tool to triage patients to an airborne infection isolation (AII) room pre- and post-bronchoscopy. OBJECTIVE: To evaluate the performance of the screening tool in detecting patients with culture-confirmed TB. DESIGN: All bronchoscopies performed between 1 March 2006 and 31 March 2010 were retrospectively reviewed. RESULTS: Of 1839 patients included (55.3% of bronchoscopies), 210 screened positive, capturing 28 culture-confirmed TB cases. Three patients with positive TB cultures screened negative. The sensitivity of the screening tool was 90.3%; the negative predictive value was 99.8%. A positive screening result was strongly predictive of a positive TB culture. CONCLUSIONS: The screening tool is effective for identifying high-risk patients and triaging them to AII rooms. The pre-bronchoscopy screening tool is simple and inexpensive to implement and has the potential to reduce intra-institutional spread of TB.


Asunto(s)
Broncoscopía/métodos , Aislamiento de Pacientes/métodos , Triaje/métodos , Tuberculosis/diagnóstico , Anciano , Femenino , Humanos , Masculino , Tamizaje Masivo/métodos , Persona de Mediana Edad , Ontario , Valor Predictivo de las Pruebas , Sala de Recuperación , Estudios Retrospectivos , Sensibilidad y Especificidad , Tuberculosis/prevención & control , Tuberculosis/transmisión
11.
Lupus ; 21(3): 271-8, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22004972

RESUMEN

Recent studies have demonstrated an inverse relationship between vitamin D levels and fatigue in systemic lupus erythematosus (SLE). The aims of this study were to evaluate proximal muscle strength, fatigue and vitamin D levels in women with SLE compared with healthy controls and to investigate relationships between these factors in a cohort of women with SLE. Forty-five women (24 SLE, 21 healthy controls) participated. Primary outcome measures were the fatigue severity scale (FSS), isometric muscle strength of dominant limbs using hand held dynamometry, two functional tests--the 30-second chair stand test and the 1-kg arm lift test, with vitamin D status measured using 25(OH)D. Overall 25(OH)D levels were 68.4 (22.4) nmol/L with no difference between SLE and control groups. There was a statistically and clinically significant difference in fatigue, 1-kg arm lift, 30-second sit to stand, knee extension, hip flexion, hip abduction, shoulder flexion and grip strength in the SLE group compared with the control group (p < 0.05). In the SLE group FSS was moderately correlated with both functional measures (1-kg arm lift r = -0.42, 30-second chair stand r = -0.44, p < 0.05). However, no statistically significant correlation between dynamometry measures and fatigue was evident. There was no association between fatigue and 25(OH)D level (r = -0.12). In summary, women with SLE were weaker and demonstrated reduced physical function and higher fatigue levels than healthy controls. Fatigue was related to physical function but not vitamin D status or maximal isometric strength in vitamin D replete individuals with SLE.


Asunto(s)
Fatiga/etiología , Lupus Eritematoso Sistémico/fisiopatología , Fuerza Muscular , Vitamina D/análogos & derivados , Adulto , Estudios de Casos y Controles , Estudios de Cohortes , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Dinamómetro de Fuerza Muscular , Índice de Severidad de la Enfermedad , Vitamina D/sangre
12.
Lupus ; 20(2): 144-50, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21303829

RESUMEN

The aim of this study was to evaluate the test-retest reliability and determine the degree of measurement error of tests of isometric muscle strength and upper and lower limb function in women with systemic lupus erythematosus (SLE). Twelve women with SLE (age 39.8 ± 10 years) were assessed on two occasions separated by a 7-10-day interval. Strength of six muscle groups was measured using a hand-held dynamometer; function was measured by the 30-s sit to stand test and the 30-s 1 kg arm lift. Relative reliability was estimated using the intraclass correlation coefficient (ICC), model 2,1 (ICC2,1). Absolute reliability was estimated using standard error measurement and the minimal detectable difference was calculated. All ICCs were greater than 0.87. Muscle strength would need to increase by between 18% and 39% in women with SLE to be 95% confident of detecting real changes. The functional tests demonstrated a systematic bias between trials. This study demonstrates that hand-held dynamometry in SLE can be performed with excellent reliability. Further work needs to be completed to determine the number of trials necessary for both the 30-s sit to stand and 30-s 1 kg arm lift to decrease the systematic bias.


Asunto(s)
Lupus Eritematoso Sistémico/fisiopatología , Dinamómetro de Fuerza Muscular/normas , Adolescente , Adulto , Femenino , Humanos , Contracción Isométrica/fisiología , Extremidad Inferior/fisiopatología , Persona de Mediana Edad , Fuerza Muscular/fisiología , Debilidad Muscular/fisiopatología , Reproducibilidad de los Resultados , Extremidad Superior/fisiopatología , Adulto Joven
13.
Osteoporos Int ; 22(3): 859-71, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20924748

RESUMEN

UNLABELLED: This systematic review demonstrates that vitamin D supplementation does not have a significant effect on muscle strength in vitamin D replete adults. However, a limited number of studies demonstrate an increase in proximal muscle strength in adults with vitamin D deficiency. INTRODUCTION: The purpose of this study is to systematically review the evidence on the effect of vitamin D supplementation on muscle strength in adults. METHODS: A comprehensive systematic database search was performed. Inclusion criteria included randomised controlled trials (RCTs) involving adult human participants. All forms and doses of vitamin D supplementation with or without calcium supplementation were included compared with placebo or standard care. Outcome measures included evaluation of strength. Outcomes were compared by calculating standardised mean difference (SMD) and 95% confidence intervals. RESULTS: Of 52 identified studies, 17 RCTs involving 5,072 participants met the inclusion criteria. Meta-analysis showed no significant effect of vitamin D supplementation on grip strength (SMD -0.02, 95%CI -0.15,0.11) or proximal lower limb strength (SMD 0.1, 95%CI -0.01,0.22) in adults with 25(OH)D levels > 25 nmol/L. Pooled data from two studies in vitamin D deficient participants (25(OH)D <25 nmol/L) demonstrated a large effect of vitamin D supplementation on hip muscle strength (SMD 3.52, 95%CI 2.18, 4.85). CONCLUSION: Based on studies included in this systematic review, vitamin D supplementation does not have a significant effect on muscle strength in adults with baseline 25(OH)D >25 nmol/L. However, a limited number of studies demonstrate an increase in proximal muscle strength in adults with vitamin D deficiency.


Asunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Suplementos Dietéticos , Hidroxicolecalciferoles/administración & dosificación , Fuerza Muscular/efectos de los fármacos , Adulto , Anciano , Anciano de 80 o más Años , Calcio de la Dieta/administración & dosificación , Femenino , Fuerza de la Mano/fisiología , Humanos , Extremidad Inferior/fisiología , Masculino , Persona de Mediana Edad , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento , Deficiencia de Vitamina D/tratamiento farmacológico
14.
AJNR Am J Neuroradiol ; 28(5): 965-70, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17494679

RESUMEN

BACKGROUND AND PURPOSE: Alzheimer disease (AD) is accompanied by macroscopic atrophy on volumetric MR imaging. A few studies have also demonstrated reduction in magnetization transfer ratio (MTR), suggesting microstructural changes in remaining brain tissue. This study assessed the value of measuring MTR in addition to volumetric MR in differentiating patients with AD from control subjects. MATERIALS AND METHODS: Volumetric T1-weighted images and 3D MTR maps were obtained from 18 patients with AD and 18 age-matched control subjects. Whole-brain (WB) and total hippocampal (Hc) volumes were measured using semiautomated techniques and adjusted for total intracranial volume. Mean MTR was obtained for WB and in the Hc region. Histogram analysis was performed for WB MTR. Among patients, associations between volumetric and MTR parameters and the Mini-Mental State Examination (MMSE) were explored. RESULTS: Patients with AD had significantly reduced WB volume (P<.0001) and mean WB MTR (P=.002) and Hc volume (P<.0001) and Hc mean MTR (P<.0001) compared with control subjects. Histogram analysis of WB MTR revealed significant reduction in the 25th percentile point in patients with AD (P=.03). Both WB volume and mean MTR were independently associated with case-control status after adjusting for the other using linear regression models. However, measuring Hc mean MTR added no statistically significant discriminatory value over and above Hc volume measurement alone. Of all MR imaging parameters, only WB volume was significantly correlated with MMSE (r=0.47, P=.048). CONCLUSIONS: This study demonstrates the independent reduction of WB volume and mean MTR in AD. This suggests that the 2 parameters reflect complementary aspects of the AD pathologic lesion at macrostructural and microstructural levels.


Asunto(s)
Enfermedad de Alzheimer/patología , Encéfalo/patología , Imagen por Resonancia Magnética , Anciano , Atrofia , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad
15.
J Biomed Opt ; 11(4): 041109, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16965137

RESUMEN

With the advent of such systems as the airborne laser and advanced tactical laser, high-energy lasers that use 1315-nm wavelengths in the near-infrared band will soon present a new laser safety challenge to armed forces and civilian populations. Experiments in nonhuman primates using this wavelength have demonstrated a range of ocular injuries, including corneal, lenticular, and retinal lesions as a function of pulse duration. American National Standards Institute (ANSI) laser safety standards have traditionally been based on experimental data, and there is scant data for this wavelength. We are reporting minimum visible lesion (MVL) threshold measurements using a porcine skin model for two different pulse durations and spot sizes for this wavelength. We also compare our measurements to results from our model based on the heat transfer equation and rate process equation, together with actual temperature measurements on the skin surface using a high-speed infrared camera. Our MVL-ED50 thresholds for long pulses (350 micros) at 24-h postexposure are measured to be 99 and 83 J cm(-2) for spot sizes of 0.7 and 1.3 mm diam, respectively. Q-switched laser pulses of 50 ns have a lower threshold of 11 J cm(-2) for a 5-mm-diam top-hat laser pulse.


Asunto(s)
Quemaduras/fisiopatología , Rayos Infrarrojos/efectos adversos , Rayos Láser/efectos adversos , Modelos Biológicos , Traumatismos por Radiación/fisiopatología , Temperatura Cutánea/efectos de la radiación , Piel/lesiones , Animales , Quemaduras/etiología , Quemaduras/patología , Simulación por Computador , Umbral Diferencial/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Técnicas In Vitro , Dosis de Radiación , Traumatismos por Radiación/etiología , Traumatismos por Radiación/patología , Medición de Riesgo/métodos , Factores de Riesgo , Piel/patología , Piel/efectos de la radiación , Porcinos
16.
Science ; 312(5779): 1537-40, 2006 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-16763154

RESUMEN

How does the bilingual brain distinguish and control which language is in use? Previous functional imaging experiments have not been able to answer this question because proficient bilinguals activate the same brain regions irrespective of the language being tested. Here, we reveal that neuronal responses within the left caudate are sensitive to changes in the language or the meaning of words. By demonstrating this effect in populations of German-English and Japanese-English bilinguals, we suggest that the left caudate plays a universal role in monitoring and controlling the language in use.


Asunto(s)
Núcleo Caudado/fisiología , Multilingüismo , Adulto , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Neuronas/fisiología , Tomografía de Emisión de Positrones , Semántica
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