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1.
J Anim Sci ; 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39360624

RESUMO

Residual feed intake (RFI), a metric of feed efficiency, is moderately heritable and independent of body size and productivity, making it an ideal trait for investigation as a selection criterion to improve feed efficiency of growing cattle. The objective of this study was to examine the differences in performance, feed efficiency, feeding behavior, gas flux, and nutrient digestibility in Holstein heifers with divergent genomically enhanced breeding values for RFI (RFIg). Holstein heifers (n = 55; BW = 352 ± 64 kg) with low (n = 29) or high (n = 26) RFIg were selected from a contemporary group of 453 commercial Holstein heifers. Heifers were rotated between 1 of 2 pens, each equipped with four electronic feed bunks and one pen with a GreenFeed gaseous exchange monitoring (GEM) system. Individual dry matter intake (DMI) and feeding behavior data were collected for 84-d. Body weight (BW) was measured weekly and spot fecal samples collected at weighing. Phenotypic RFI (RFIp) was calculated as the residual from regression of DMI on average daily gain (ADG) and mid-test metabolic BW (BW0.75). A mixed model including the fixed effect of RFIg classification and random effect of group was used to evaluate the effect of RFIg classification on response variables. There were no differences (P > 0.05) in BW and ADG for heifers with divergent RFIg; however, low RFIg heifers consumed 7.5% less (P < 0.05) feed per day. Consequently, low RFIg heifers exhibited a more favorable (P < 0.05) RFIp (-0.196 vs 0.222 kg/d, respectively). Low RFIg heifers had 8.7% fewer (P < 0.05) bunk visit (BV) events per day and tended to have a 11.2% slower (P < 0.10) eating rate. Low RFIg heifers had 7.7% lower (P < 0.05) methane (CH4) emissions (g/d), 6.1% lower (P ≤ 0.05) carbon dioxide (CO2) production (g/d), and 5.6% lower (P ≤ 0.05) heat production (Mcal/d) than high RFIg heifers. However, CH4 yield and CO2 yield (g/kg DMI), and heat production per unit DMI (Mcal/kg DMI) did not differ (P > 0.05) between heifers with divergent RFIg. Dry matter and nutrient digestibility did not differ (P > 0.05) between heifers with divergent RFIg. Overall, heifers selected to be more feed efficient exhibited more favorable energy efficiencies and feed efficiency phenotypes. Results suggest that selection based on RFIg provides opportunities to select cattle with favorable feed efficiency phenotypes to increase the economic and environmental sustainability of the cattle industry.

2.
Life Sci Space Res (Amst) ; 42: 74-83, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39067994

RESUMO

Human space exploration expansion from Low-Earth Orbit to deep space is accelerating the need to monitor and address the known health concerns related to deep space radiation. The human musculoskeletal system is vulnerable to these risks (alongside microgravity) and its health reflects the well-being of other body systems. Multiparametric magnetic resonance imaging (MRI) is an important approach for assessing temporal physiological changes in the musculoskeletal system. We propose that ultra-low-field MRI provides an optimal low Size Weight and Power (SwaP) solution for non-invasively monitoring muscle and bone changes on the planned Gateway lunar space station. Our proposed ultra-low-field Gateway MRI meets low SWaP design specifications mandated by limited room in the lunar space station. This review summarizes the current state of our knowledge on musculoskeletal consequences of spaceflight, especially with respect to radiation, and then elaborates how MRI can be used to monitor the deleterious effects of space travel and the efficacy of putative countermeasures. We argue that an ultra-low-field MRI in cis-lunar space on the Gateway can provide valuable research and medical insights into the effects of deep space radiation exposure on astronauts. Such an MRI would also allow the development of imaging protocols that would facilitate Earth-bound teams to monitor space personnel musculoskeletal changes during future interplanetary spaceflight. It will especially have a role in monitoring countermeasures, such as the use of melanin, in protecting space explorers.


Assuntos
Imageamento por Ressonância Magnética , Voo Espacial , Humanos , Imageamento por Ressonância Magnética/métodos , Sistema Musculoesquelético/diagnóstico por imagem , Sistema Musculoesquelético/efeitos da radiação , Astronautas , Ausência de Peso , Radiação Cósmica/efeitos adversos
3.
Med Phys ; 50(12): 7441-7461, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37830895

RESUMO

BACKGROUND: The Tomosynthesis Mammography Imaging Screening Trial (TMIST), EA1151 conducted by the Eastern Cooperative Oncology Group (ECOG)/American College of Radiology Imaging Network (ACRIN) is a randomized clinical trial designed to assess the effectiveness for breast cancer screening of digital breast tomosynthesis (TM) compared to digital mammography (DM). Equipment from multiple vendors is being used in the study. PURPOSE: For the findings of the study to be valid and capture the true capacities of the two technology types, it is important that all equipment is operated within appropriate parameters with regard to image quality and dose. A harmonized QC program was established by a core physics team. Since there are over 120 trial sites, a centralized, automated QC program was chosen as the most practical design. This report presents results of the weekly QC testing program. A companion paper will review quality monitoring based on data from the headers of the patient images. METHODS: Study images are collected centrally after de-identification using the "TRIAD" application developed by ACR. The core physics team devised and implemented a minimal set of quality control (QC) tests to evaluate the tomosynthesis and 2D mammography systems. Weekly, monthly and annual testing is performed by the site mammography technologists with images submitted directly to the physics core. The weekly physics QC tests are described: SDNR of a low-contrast mass object, artifact spread, spatial resolution, tracking of technical factors, and in-slice noise power spectra. RESULTS: As of December 31, 2022 (5 years), 145 sites with 411 machines had submitted QC data. A total of 136 742 TMIST participant screening imaging studies had been performed. The 5th and 95th percentile mean glandular doses for a single tomosynthesis exposure to a 4.0 cm thick PMMA phantom ("standard breast phantom") were 1.24 and 1.68 mGy respectively. The largest sources of QC non-conformance were: operator error, not following the QC protocol exactly, unreported software updates and preventive maintenance activities that affected QC setpoints. Noise power spectra were measured, however, standardization of performance targets across machine types and software revisions was difficult. Nevertheless, for each machine type, test measurement results were very consistent when the protocol was followed. Deviations in test results were mostly related to software and hardware changes. CONCLUSION: Most systems performed very consistently. Although this is a harmonized program using identical phantoms and testing protocols, it is not appropriate to apply universal threshold or target metrics across the machine types because the systems have different non-linear reconstruction algorithms and image display filters. It was found to be more useful to assess pass/fail criteria in terms of relative deviations from baseline values established when a system is first characterized and after equipment is changed. Generally, systems which needed repair failed suddenly, but in retrospect, for a few cases, drops in SDNR and increases in mAs were observed prior to tube failure. TMIST is registered as NCT03233191 by Clinicaltrials.gov.


Assuntos
Neoplasias da Mama , Mamografia , Humanos , Feminino , Mamografia/métodos , Mama , Neoplasias da Mama/diagnóstico por imagem , Algoritmos , Controle de Qualidade , Imagens de Fantasmas
4.
Med Phys ; 50(12): 7427-7440, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37824821

RESUMO

PURPOSE: A comprehensive, centrally-monitored physics quality control (QC) program was developed for the Tomosynthesis Imaging Screening Trial (TMIST), a randomized controlled trial of digital breast tomosynthesis (TM) versus digital mammography (DM) for cancer screening. As part of the program, in addition to a set of phantom-based tests, de-identified data on image acquisition and processing parameters were captured from the DICOM headers of all individual patient images in the trial. These data were analyzed to assess the potential usefulness of header data from digital mammograms and tomosynthesis images of patients for quality assurance in breast imaging. METHODS: Data were automatically extracted from the headers of all de-identified patient mammograms and tomosynthesis images in the TMIST study. Image acquisition parameters and estimated radiation doses were tracked for individual sites, systems and across system types. These parameters included (among others) kV, target/filter use, number of acquired views per examination, AEC mode, compression thickness and force and detector temperature. Consistency of manually entered study data parameters (subject ID, screening time-point) from TMIST was evaluated. Preliminary observations from the program are presented. RESULTS: We report on data from 812 651 images from 135 525 examinations acquired between October, 2017 and December, 2022. Data came from 6 system models from 3 manufacturers. There was greater variability both in the number of views used and in the estimated (proxy) doses received in DM exams compared to TM. Mean proxy doses per examination varied among manufacturers from 2.76-4.54 mGy for DM and 3-4.84 mGy for the tomosynthesis component in the TM arm with maximum examination proxy doses of 20 and 26 mGy for DM and TM respectively. Mean proxy doses per examination for the combination examination in TM (tomosynthesis plus digital mammography) varied from 6.6 to 7.6 mGy among manufacturers with a maximum of 44.5 mGy. CONCLUSIONS: Overall, modern digital mammography and tomosynthesis systems used in TMIST have operated very reliably. Doses vary considerably due to variation in the number of views per examination, thickness and fibro-glandularity of the breast, and choices in the use of synthesized versus actual 2D mammography in the TM examination. These data may also be useful in predicting equipment problems. Header information is valuable not only for automated QC, but also for cross-checking accuracy and consistency of data in a clinical study.


Assuntos
Neoplasias da Mama , Detecção Precoce de Câncer , Humanos , Feminino , Doses de Radiação , Mamografia/métodos , Mama/diagnóstico por imagem , Imagens de Fantasmas , Neoplasias da Mama/diagnóstico por imagem
5.
Brachytherapy ; 21(6): 806-813, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36220758

RESUMO

AIMS: Interstitial brachytherapy (ISBT) is an effective option for delivering conformal high dose radiation to the target volume with better organ-at risk sparing but is thought to be more invasive and painful than other methods. This study investigated pain levels and opioid consumption in patients who received spinal anesthesia (SA) or general anesthesia (GA) for their ISBT. MATERIALS AND METHODS: Patients that underwent ISBT from April 2014 to September 2018 were analyzed from a prospective institutional database. The most prevalent malignancies were cervical (45%), recurrent endometrial (27%) and vaginal (20%) cancers. Baseline patient characteristics, radiation treatment details, anesthesia records, and inpatient charts were obtained. Opioid consumption was quantified as oral morphine equivalent per day (OMEq/day) from implantation until removal. Pain score levels were collected by using an 11-point scoring system. RESULTS: Ninety nine patients received GA and 40 patients received SA as their anesthesia for ISBT. During their first admission, 76 patients (55%) required intravenous opioids. Patients receiving SA had significantly lower mean pain scores on the morning of their procedure 6 (Interquartile range [IQR] 2-8) vs. 0 (IQR: 0-1); p < 0.001]. Pain did not significantly differ between cohorts at any other time. During the first admission, SA patients had a lower median opioid usage of 23 (IQR: 9-47) mg/day compared to GA patients at 38 (IQR: 21-71) mg/day (p = 0.011). No difference in opioid consumption was seen during subsequent admissions. CONCLUSIONS: In patients undergoing ISBT, SA provides better immediate pain control post insertion compared to GA. Patients who received SA used lower amounts of opioids during their first ISBT insertion.


Assuntos
Raquianestesia , Braquiterapia , Neoplasias dos Genitais Femininos , Feminino , Humanos , Braquiterapia/métodos , Analgésicos Opioides/uso terapêutico , Estudos Prospectivos , Neoplasias dos Genitais Femininos/radioterapia , Neoplasias dos Genitais Femininos/patologia , Anestesia Geral/métodos , Dor
6.
Chem Rev ; 122(9): 9198-9263, 2022 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-35404590

RESUMO

Hydraulic fracturing of unconventional oil/gas shales has changed the energy landscape of the U.S. Recovery of hydrocarbons from tight, hydraulically fractured shales is a highly inefficient process, with estimated recoveries of <25% for natural gas and <5% for oil. This review focuses on the complex chemical interactions of additives in hydraulic fracturing fluid (HFF) with minerals and organic matter in oil/gas shales. These interactions are intended to increase hydrocarbon recovery by increasing porosities and permeabilities of tight shales. However, fluid-shale interactions result in the dissolution of shale minerals and the release and transport of chemical components. They also result in mineral precipitation in the shale matrix, which can reduce permeability, porosity, and hydrocarbon recovery. Competition between mineral dissolution and mineral precipitation processes influences the amounts of oil and gas recovered. We review the temporal/spatial origins and distribution of unconventional oil/gas shales from mudstones and shales, followed by discussion of their global and U.S. distributions and compositional differences from different U.S. sedimentary basins. We discuss the major types of chemical additives in HFF with their intended purposes, including drilling muds. Fracture distribution, porosity, permeability, and the identity and molecular-level speciation of minerals and organic matter in oil/gas shales throughout the hydraulic fracturing process are discussed. Also discussed are analysis methods used in characterizing oil/gas shales before and after hydraulic fracturing, including permeametry and porosimetry measurements, X-ray diffraction/Rietveld refinement, X-ray computed tomography, scanning/transmission electron microscopy, and laboratory- and synchrotron-based imaging/spectroscopic methods. Reactive transport and spatial scaling are discussed in some detail in order to relate fundamental molecular-scale processes to fluid transport. Our review concludes with a discussion of potential environmental impacts of hydraulic fracturing and important knowledge gaps that must be bridged to achieve improved mechanistic understanding of fluid transport in oil/gas shales.


Assuntos
Fraturamento Hidráulico , Minerais/química , Gás Natural , Campos de Petróleo e Gás , Águas Residuárias/química
7.
Med Phys ; 48(7): 3623-3629, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33931863

RESUMO

PURPOSE: In the reconstruction of volume breast images from x-ray projections in breast tomosynthesis, some tomographic systems truncate the image data presented to the radiologist such that a non-negligible amount of tissue may be missing from the breast image. QC tests were conducted to determine if this problem existed in imaging in the TMIST study. METHODS: Test tools developed for TMIST containing small objects at known heights were used in routine weekly and annual QC testing of tomosynthesis units to assess the degree to which phantom material that was irradiated in imaging was excluded from the reconstructed image. Results from 318 tests on five system types from three manufacturers are reported. RESULTS: The presence and extent of this problem varied among system types. The cause was most frequently related to machine errors in the determination of breast thickness or to deflection of components during breast compression. In particular, the problem occurred when a compression paddle other than the one calibrated for tomosynthesis was used for the tests. This was also verified to have occurred in some clinical imaging. CONCLUSIONS: Missing volume can be avoided by intentionally reconstructing additional image slices above and below the presumed locations of the breast support and compression plate. A compression paddle which has been calibrated for tomosynthesis should be used both for clinical imaging and testing. The prevalence of this phenomenon suggests that more frequent testing for volume coverage may be advisable.


Assuntos
Mama , Compressão de Dados , Mama/diagnóstico por imagem , Mamografia , Imagens de Fantasmas
8.
Cancers (Basel) ; 13(6)2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33803641

RESUMO

Approximately 91% of the world's children living with HIV (CLWH) are in sub-Saharan Africa (SSA). Living with HIV confers a risk of developing HIV-associated cancers. To determine the incidence and risk factors for cancer among CLWH, we conducted a nested case-control study of children 0-18 years from 2004-2014 at five centers in four SSA countries. Incident cases of cancer and HIV were frequency-matched to controls with HIV and no cancer. We calculated the incidence density by cancer type, logistic regression, and relative risk to evaluate risk factors of cancer. The adjusted incidence density of all cancers, Kaposi sarcoma, and lymphoma were 47.6, 36.6, and 8.94 per 100,000 person-years, respectively. Delayed ART until after 2 years of age was associated with cancer (OR = 2.71, 95% CI 1.51, 4.89) even after adjusting for World Health Organization clinical stage at the time of enrolment for HIV care (OR = 2.85, 95% CI 1.57, 5.13). The relative risk of cancer associated with severe CD4 suppression was 6.19 (p = 0.0002), 2.33 (p = 0.0042), and 1.77 (p = 0.0305) at 1, 5, and 10 years of ART, respectively. The study demonstrates the high risk of cancers in CLWH and the potential benefit of reducing this risk by the early initiation of ART.

9.
Curr Oncol ; 28(1): 716-725, 2021 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-33573158

RESUMO

Early-stage breast cancer patients comprise a large proportion of patients treated with radiotherapy in Canada. Proponents have suggested that five-fraction hypofractionated radiotherapy for these patients would result in significant cost savings. An assessment of this argument is thus warranted. The FAST-Forward and UK FAST clinical trials each demonstrated that their respective hypofractionated regimens provided equivalent outcomes compared with standard regimens. Thus, a cost-minimization analysis was performed to quantify the potential savings associated with these regimens, which were designated as FAST-Forward 1 (26 Gy/5 fractions/1 week) and FAST-Forward 2 (27 Gy/5 fractions/1 week), and UK FAST 1 (28.5 Gy/5 fractions/5 weeks) and UK FAST 2 (30 Gy/5 fractions/5 weeks). A standard regimen of 42.5 Gy/16 fractions/5 weeks was also included. A comprehensive model of radiotherapy costs for a Canadian cancer centre was created. Time, labour costs, and capital costs were calculated for each regimen and applied using established measures. The total costs per patient for the FAST-Forward trials were $851.77 for FAST-Forward 1 and $874.77 for FAST-Forward 2, providing a total savings of $487.99 and $464.99, respectively. Similarly, the total costs per patient for the FAST trials were $979.75 for UK FAST 1 and $1017.70 for UK FAST 2, providing savings of $360.01 and $322.06, respectively. Following the FAST-Forward 1 regimen results in the greatest reduction of infrastructure and human resources costs at 36.42% compared with the standard. Sensitivity analysis shows a maximum per-patient costs savings ranging from $474.60 to $508.53 for the FAST-Forward 1 trial, which translates to an annual savings of $174,700/year locally and $2.06 million/year province-wide, based on a moderate-to-large size department workload. Compared with a standard radiotherapy regimen, all FAST-Forward and UK FAST hypofractionated regimens provide cost savings for the treatment of early-stage breast cancer. The cost savings associated with each of these equivalent regimens can be directly calculated; activities in this model can easily be adjusted to account for cost variations, allowing other centres to calculate cost impacts specific to their own centres.


Assuntos
Hipofracionamento da Dose de Radiação , Canadá , Custos e Análise de Custo , Seguimentos , Humanos , Resultado do Tratamento
10.
Clin Infect Dis ; 69(11): 2022-2025, 2019 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-31102440

RESUMO

We describe 7 human immunodeficiency virus-infected Malawian children with Kaposi sarcoma who met criteria for Kaposi sarcoma herpesvirus (KSHV) inflammatory cytokine syndrome. Each presented with persistent fevers, bulky lymphadenopathy, massive hepatosplenomegaly, and severe cytopenias. Plasma analyses were performed in 2 patients, both demonstrating extreme elevations of KSHV viral load and interleukin 6.


Assuntos
Citocinas/metabolismo , Herpesvirus Humano 8/patogenicidade , Sarcoma de Kaposi/virologia , Criança , Pré-Escolar , Feminino , Infecções por HIV/mortalidade , Infecções por HIV/virologia , Humanos , Interleucina-6/metabolismo , Linfadenopatia/metabolismo , Linfadenopatia/virologia , Malaui , Masculino , Estudos Prospectivos , Estudos Retrospectivos , Sarcoma de Kaposi/metabolismo
11.
J Cutan Med Surg ; 23(2_suppl): 3S-34S, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30742778

RESUMO

BACKGROUND:: The treat-to-target (T2T) strategy has become established in several medical specialties as a key guidance to optimal therapeutic decision making. T2T may be effective in the assessment of the biologic class of agents called interleukin (IL)-17 inhibitors, which are emerging as a safe and effective treatment option for autoimmune inflammatory conditions such as plaque psoriasis, psoriatic arthritis (PsA), and ankylosing spondylitis (AS). OBJECTIVE:: The objective of this article is to use a T2T approach for the evaluation of the effectiveness and safety of IL-17 inhibitors in the management of patients with plaque psoriasis, PsA, and AS. METHODS:: Following a comprehensive literature search, a full-day meeting was convened to discuss and identify the T2T targets for psoriasis, PsA, and AS. Clinical trial evidence was presented for the approved IL-17 inhibitors-secukinumab, ixekizumab, and brodalumab-to assess whether these data meet T2T safety and efficacy targets. RESULTS:: All 3 approved agents were significantly superior to placebo and active controls in the achievement of T2T targets for psoriasis. Secukinumab and ixekizumab were likewise associated with significantly better outcomes than controls in the PsA targets, and secukinumab resulted in significant AS target improvements vs placebo. The IL-17 inhibitors were also associated with low rates of serious adverse events and exacerbations of common comorbid conditions. CONCLUSION:: Phase III trial results support the T2T benefit and safety of IL-17 inhibitors according to their specific indications for the management of patients with plaque psoriasis, PsA, and AS.


Assuntos
Fármacos Dermatológicos/uso terapêutico , Interleucina-17/antagonistas & inibidores , Psoríase/tratamento farmacológico , Espondilite Anquilosante/tratamento farmacológico , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados/uso terapêutico , Artrite Psoriásica/tratamento farmacológico , Artrite Psoriásica/metabolismo , Fármacos Dermatológicos/efeitos adversos , Humanos , Interleucina-17/metabolismo , Psoríase/metabolismo , Espondilite Anquilosante/metabolismo
12.
Int J Cancer ; 144(1): 110-116, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30204240

RESUMO

Kaposi sarcoma (KS) is among the most common childhood malignancies in central, eastern, and southern Africa. Although its unique clinical features have been established, biological mechanisms related to the causative agent, KS-associated herpes-virus (KSHV), have yet to be explored in children. We performed a prospective observational pilot study to explore associations between KSHV viral load (VL), human interleukin-6 (IL-6) and IL-10 levels, and clinical characteristics of 25 children with KS in Lilongwe, Malawi from June 2013-August 2015. The median age was 6.4 years. Lymphadenopathy was the most common site of KS involvement (64%), followed by skin and oral mucosa (44% each), woody edema (12%), and pulmonary (8%). Baseline samples for plasma KSHV VL, IL-6 and IL-10 analyses were available for 18/25 patients (72%) at time of KS diagnosis. KSHV VL was detectable at baseline in 12/18 (67%) patients, the median baseline IL-6 level was 8.53 pg/mL (range 4.31-28.33), and the median baseline IL-10 level was 19.53 pg/mL (range 6.91-419.69). Seven (39%) patients presented with an IL-6 level > 10 pg/mL (exceeding twice the upper limit of normal). Detectable KSHV VL was significantly associated with lymphadenopathic KS (p = 0.004), while having undetectable KSHV VL was associated with a higher likelihood of presenting with hyperpigmented skin lesions (p = 0.01). Detectable KSHV VL and elevated IL-6 levels are present in a subset of children with KS. Lytic activation of KSHV and associated elevation in KSHV VL may contribute to the unique clinical manifestations of pediatric KS in KSHV-endemic regions of Africa.


Assuntos
Infecções por HIV/metabolismo , Infecções por Herpesviridae/metabolismo , Interleucina-6/metabolismo , Sarcoma de Kaposi/metabolismo , Carga Viral , Adolescente , Criança , Pré-Escolar , Doenças Endêmicas , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , Infecções por Herpesviridae/epidemiologia , Infecções por Herpesviridae/virologia , Herpesvirus Humano 8/fisiologia , Humanos , Lactente , Malaui/epidemiologia , Masculino , Projetos Piloto , Estudos Prospectivos , Sarcoma de Kaposi/epidemiologia , Sarcoma de Kaposi/virologia , Ativação Viral/fisiologia
13.
Exp Eye Res ; 183: 20-28, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30445049

RESUMO

Navigating unfamiliar indoor spaces while visually searching for objects of interest is a challenge faced by people with visual impairment. We asked how restricting visual acuity of normally sighted subjects would affect visual search and navigation in a real world environment, and how their performance would compare to subjects with naturally occurring low vision. Two experiments were conducted. In the first, 8 normally sighted subjects walked along an indoor path, looking for objects placed at unpredictable intervals to the left and right of the path, and identified single letters posted on the objects. A head-mounted eye tracker was used to assess their gaze direction in the environment. For half the trials, blur foils were used to restrict visual acuity to approximately logMAR 1.65. Gaze behavior, travel time, and letter recognition accuracy were compared between blurred and unrestricted conditions. In the second experiment, the same procedure was conducted, but performance was compared between acuity-restricted normally-sighted subjects and subjects with naturally occurring low vision (mean acuity 1.09 logMAR, range 0.48-1.85 logMAR). In Experiment 1, neither Blur nor the Letter Recognition Task individually had a statistically significant effect on travel time. However, when combined, there was an interaction between the two that increased travel time by approximately 63%, relative to baseline trials. Blur modified gaze behavior such that subjects spent more time looking down toward the floor while walking, at the expense of time spent looking in other directions. During Letter Recognition Task trials with Blur, subjects spent extra time examining objects, though more objects were missed altogether. In Experiment 2, low-vision subjects spent more time looking toward the boundary between the floor and the wall, but gaze patterns were otherwise similar to acuity-restricted subjects with normal vision. Low-vision subjects were also more likely to miss objects compared to acuity-restricted subjects. We conclude that under conditions of artificially restricted acuity, normally sighted subjects look downward toward the floor more frequently while navigating and take extra time to examine objects of interest, but are less likely to detect them. Low-vision subjects tend to direct their gaze toward the boundary between the wall and the floor, which may serve as a high contrast cue for navigation.


Assuntos
Baixa Visão/fisiopatologia , Acuidade Visual/fisiologia , Percepção Visual/fisiologia , Caminhada/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Adulto Jovem
15.
Magn Reson Imaging ; 46: 47-55, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29109052

RESUMO

While the idea of using spatial encoding fields (SEM) for image formation has been proven, conventional wisdom still holds that a magnetic resonance imaging (MRI) system begins with a highly uniform magnetic field. In particular, radio frequency (RF) encoding MRIs designed and tested to date have largely used uniform magnetic fields. Here we demonstrate magnetic resonance imaging in a magnetic field with a built-in gradient that gives non-planar slices - curved surfaces - when the nuclear spins are excited with narrow band RF pulses. Image encoding on these naturally occurring non-planar slices was accomplished with RF encoding using a non-linear spatially varying B1 phase gradient. The imaging methods were demonstrated on a small prototype MRI instrument. The MRI has no switched magnetic field gradients - it is "gradient-free". A low field gradient-free MRI with low mass permanent magnets and simple, low power, RF encoding hardware is ideal for deployment on the International Space Station for the study of astronaut muscle and bone mass loss. Gradient-free natural slice encoding MRI designs would also be portable enough for application in remote terrestrial locations, in emergency rooms and in operating rooms where they can be used with minimally invasive and robotic surgery.


Assuntos
Campos Magnéticos , Imageamento por Ressonância Magnética , Imagens de Fantasmas , Algoritmos , Magnetismo , Salas Cirúrgicas , Ondas de Rádio , Razão Sinal-Ruído , Voo Espacial
16.
Environ Sci Technol ; 51(17): 9817-9825, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28783317

RESUMO

Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.


Assuntos
Silicatos de Alumínio , Cromo/química , Ferro , Poluentes Químicos da Água/química , Argila , Cinética , Minerais , Oxirredução
17.
Clin Exp Allergy ; 47(12): 1534-1545, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28833774

RESUMO

BACKGROUND: Bronchial epithelial goblet cell metaplasia (GCM) with hyperplasia is a prominent feature of asthma, but the effects of treatment with corticosteroids alone or in combination with a long-acting ß2 -adrenergic receptor agonist (LABA) on GCM in the bronchial epithelium are unknown. OBJECTIVES: To determine whether corticosteroid alone or in combination with a LABA alters protein and gene expression pathways associated with IL-13-induced goblet cell metaplasia. RESULTS: We evaluated the effects of fluticasone propionate (FP) and of salmeterol (SM), on the response of well-differentiated cultured bronchial epithelial cells to interleukin-13 (IL-13). Outcome measures included gene expression of SPDEF/FOXa2, gene expression and protein production of MUC5AC/MUC5B and morphologic appearance of cultured epithelial cell sheets. We additionally analysed expression of these genes in bronchial epithelial brushings from healthy, steroid-naïve asthmatic and steroid-treated asthmatic subjects. In cultured airway epithelial cells, FP treatment inhibited IL-13-induced suppression of FOXa2 gene expression and up-regulation of SPDEF, alterations in gene and protein measures of MUC5AC and MUC5B and induction of GCM. The addition of SM synergistically modified the effects of FP modestly-only for gel-forming mucin MUC5AC. In bronchial epithelial cells recovered from asthmatic vs healthy human subjects, we found FOXa2 and MUC5B gene expression to be reduced and SPDEF and MUC5AC gene expression to be increased; these alterations were not observed in bronchial epithelial cells recovered after treatment with inhaled corticosteroids. CONCLUSION AND CLINICAL RELEVANCE: Corticosteroid treatment inhibits IL-13-induced GCM of the airways in asthma, possibly through its effects on SPDEF and FOXa2 regulation of mucin gene expression. These effects are modestly augmented by the addition of a long-acting ß-agonist. As we found evidence for drug treatment counteracting the effects of IL-13 on the epithelium, we conclude that further exploration into the mechanisms by which corticosteroids and long-acting ß2 -adrenergic agonists confer protection against pathologic airway changes is warranted.


Assuntos
Corticosteroides/efeitos adversos , Agonistas de Receptores Adrenérgicos beta 2/efeitos adversos , Células Caliciformes/efeitos dos fármacos , Células Caliciformes/patologia , Corticosteroides/metabolismo , Corticosteroides/uso terapêutico , Agonistas de Receptores Adrenérgicos beta 2/uso terapêutico , Asma/complicações , Asma/tratamento farmacológico , Biomarcadores , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Fluticasona/efeitos adversos , Fluticasona/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células Caliciformes/metabolismo , Fator 3-beta Nuclear de Hepatócito/genética , Fator 3-beta Nuclear de Hepatócito/metabolismo , Humanos , Interleucina-13/farmacologia , Metaplasia , Mucinas/genética , Mucinas/metabolismo , Proteínas Proto-Oncogênicas c-ets/genética , Proteínas Proto-Oncogênicas c-ets/metabolismo , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Xinafoato de Salmeterol/efeitos adversos , Xinafoato de Salmeterol/farmacologia
18.
J Cutan Med Surg ; 21(6): 497-501, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28614954

RESUMO

Health literacy refers to the comprehension required to make well-informed decisions regarding one's health. It is a critical component in helping patients to understand how to take their medications appropriately. However, many patients do not possess the comprehension necessary for medication adherence. The result of poor literacy is a higher incidence of misunderstanding medication instructions. Visual aids have the ability to transcend language and numeracy barriers and can therefore improve the effectiveness of communication and broaden target audiences. To enhance communication that is language independent, a template was created to provide instructions for proper use and explanation of risks for adverse events. This template is designed to fit on a single double-sided page. This template can be adapted for use in explaining any medication using universal pictograms available from online resources. This would enable any practitioner to design information sheets for their unique use.


Assuntos
Recursos Audiovisuais , Comunicação , Educação de Pacientes como Assunto/métodos , Letramento em Saúde , Humanos , Isotretinoína/administração & dosagem , Isotretinoína/efeitos adversos
19.
J Back Musculoskelet Rehabil ; 30(2): 363-370, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27392848

RESUMO

BACKGROUND: Two-thirds of adults worldwide will experience low back pain at some point in their life. In the following case series, we present four patients with sacroiliac (SI) joint instability and severe chronic low back pain, which was refractory to other treatment modalities. OBJECTIVE: We investigated the efficacy of platelet-rich plasma (PRP) injections, a novel orthobiologic therapy, for reducing SI joint pain, improving quality of life, and maintaining a clinical effect. METHODS: Short-form McGill Pain Questionnaire (SFM), Numeric Rating Scale (NRS), and Oswestry Low Back Pain and Disability Index were used for evaluation of treatment at pretreatment, 12-months and 48-months after treatment. RESULTS: At follow-up 12-months post-treatment, pooled data from all patients reported a marked improvement in joint stability, a statistically significant reduction in pain, and improvement in quality of life. The clinical benefits of PRP were still significant at 4-years post-treatment. CONCLUSIONS: Platelet-rich plasma therapy exhibits clinical usefulness in both pain reduction and for functional improvement in patients with chronic SI joint pain. The improvement in joint stability and low back pain was maintained at 1- and 4-years post-treatment.


Assuntos
Dor Lombar/terapia , Plasma Rico em Plaquetas , Articulação Sacroilíaca/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Injeções Intra-Articulares , Dor Lombar/diagnóstico por imagem , Pessoa de Meia-Idade , Medição da Dor , Qualidade de Vida , Resultado do Tratamento , Ultrassonografia de Intervenção
20.
PLoS One ; 11(4): e0153335, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27082863

RESUMO

Kaposi sarcoma (KS) is the most common HIV-associated malignancy in children and adolescents in Africa. Pediatric KS is distinct from adult disease. We evaluated the clinical characteristics associated with long-term outcomes. We performed a retrospective observational analysis of 70 HIV-infected children and adolescents with KS less than 18 years of age diagnosed between 8/2010 and 6/2013 in Lilongwe, Malawi. Local first-line treatment included bleomycin and vincristine plus nevirapine-based highly active anti-retroviral therapy (HAART). Median age was 8.6 years (range 1.7-17.9); there were 35 females (50%). Most common sites of presentation were: lymph node (74%), skin (59%), subcutaneous nodules (33%), oral (27%), woody edema (24%), and visceral (16%). Eighteen (26%) presented with lymphadenopathy only. Severe CD4 suppression occurred in 28%. At time of KS diagnosis, 49% were already on HAART. Overall, 28% presented with a platelet count < 100 x 109/L and 37% with hemoglobin < 8 g/dL. The 2-year event-free (EFS) and overall survival (OS) were 46% and 58% respectively (median follow-up 29 months, range 15-50). Multivariable analysis of risk of death and failure to achieve EFS demonstrated that visceral disease (odds ratios [OR] 19.08 and 11.61, 95% CI 2.22-163.90 and 1.60-83.95 respectively) and presenting with more than 20 skin/oral lesions (OR 9.57 and 22.90, 95% CI 1.01-90.99 and 1.00-524.13 respectively) were independent risk factors for both. Woody edema was associated with failure to achieve EFS (OR 7.80, 95% CI 1.84-33.08) but not death. Univariable analysis revealed that lymph node involvement was favorable for EFS (OR 0.28, 95% CI 0.08-0.99), while T1 TIS staging criteria, presence of cytopenias, and severe immune suppression were not associated with increased mortality. Long-term complete remission is achievable in pediatric KS, however outcomes vary according to clinical presentation. Based on clinical heterogeneity, treatment according to risk-stratification is necessary to improve overall outcomes.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Infecções por HIV/tratamento farmacológico , Sarcoma de Kaposi/tratamento farmacológico , Adolescente , Bleomicina/administração & dosagem , Criança , Pré-Escolar , Feminino , Infecções por HIV/complicações , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , HIV-1 , Humanos , Lactente , Masculino , Prognóstico , Indução de Remissão , Estudos Retrospectivos , Sarcoma de Kaposi/diagnóstico , Sarcoma de Kaposi/epidemiologia , Fatores Socioeconômicos , Fatores de Tempo , Vincristina/administração & dosagem
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