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1.
J Cyst Fibros ; 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38490920

RESUMO

BACKGROUND: Iron deficiency (ID) is a common extrapulmonary manifestation in cystic fibrosis (CF). CF transmembrane conductance regulator (CFTR) modulator therapies, particularly highly-effective modulator therapy (HEMT), have drastically improved health status in a majority of people with CF. We hypothesize that CFTR modulator use is associated with improved markers of ID. METHODS: In a multicenter retrospective cohort study across 4 United States CF centers 2012-2022, the association between modulator therapies and ID laboratory outcomes was estimated using multivariable linear mixed effects models overall and by key subgroups. Summary statistics describe the prevalence and trends of ID, defined a priori as transferrin saturation (TSAT) <20 % or serum iron <60 µg/dL (<10.7 µmol/L). RESULTS: A total of 568 patients with 2571 person-years of follow-up were included in analyses. Compared to off modulator therapy, HEMT was associated with +8.4 % TSAT (95 % confidence interval [CI], +6.3-10.6 %; p < 0.0001) and +34.4 µg/dL serum iron (95 % CI, +26.7-42.1 µg/dL; p < 0.0001) overall; +5.4 % TSAT (95 % CI, +2.8-8.0 %; p = 0.0001) and +22.1 µg/dL serum iron (95 % CI, +13.5-30.8 µg/dL; p < 0.0001) in females; and +11.4 % TSAT (95 % CI, +7.9-14.8 %; p < 0.0001) and +46.0 µg/dL serum iron (95 % CI, +33.3-58.8 µg/dL; p < 0.0001) in males. Ferritin was not different in those taking modulator therapy relative to off modulator therapy. Hemoglobin was overall higher with use of modulator therapy. The prevalence of ID was high throughout the study period (32.8 % in those treated with HEMT). CONCLUSIONS: ID remains a prevalent comorbidity in CF, despite availability of HEMT. Modulator use, particularly of HEMT, is associated with improved markers for ID (TSAT, serum iron) and anemia (hemoglobin).

2.
Front Psychol ; 14: 1101353, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36814666

RESUMO

In March 2020, COVID-19 brought illness, lockdowns, and economic turmoil worldwide. Studies from March-April 2020 reported increased psychological distress, especially among younger (vs. older) adults. Here, we examine whether age differences persisted in a 29-wave longitudinal survey conducted with an American national life-span sample over the first 16 months of the pandemic. Socio-emotional selectivity theory (SST) predicts that older age will be consistently associated with lower psychological distress due to life-span changes in motivation, while the strength and vulnerability integration model (SAVI) posits that age differences in psychological distress will diminish under prolonged stress. We find that younger adults consistently reported more psychological distress than older adults, though age differences did decrease over time. Prior diagnosis with anxiety or depression additionally predicted greater psychological distress throughout the study, but did not moderate age differences. We discuss implications for psychological theories of aging and interventions to reduce psychological distress.

3.
J Gerontol B Psychol Sci Soc Sci ; 78(1): 51-61, 2023 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-35972470

RESUMO

OBJECTIVES: This research addresses how younger and older adults' decisions and evaluations of gains and losses are affected by the way in which monetary incentives are provided. We compared 2 common incentive schemes in decision making: pay one (only a single decision is incentivized) and pay all (incentives across all decisions are accumulated). METHOD: Younger adults (18-36 years; n = 147) and older adults (60-89 years; n = 139) participated in either a pay-one or pay-all condition and made binary choices between two-outcome monetary lotteries in gain, loss, and mixed domains. We analyzed participants' decision quality, risk taking, and psychometric test scores. Computational modeling of cumulative prospect theory served to measure sensitivity to outcomes and probabilities, loss aversion, and choice sensitivity. RESULTS: Decision quality and risk aversion were higher in the gain than mixed or loss domain, but unaffected by age. Loss aversion was higher, and choice sensitivity was lower in older than younger adults. In the pay-one condition, the value functions were more strongly curved, and choice sensitivity was higher than in the pay-all condition. DISCUSSION: An opportunity of accumulating incentives has similar portfolio effects on younger and older adults' decisions. In general, people appear to decide less cautiously in pay-all than pay-one scenarios. The impact of different incentive schemes should be carefully considered in aging and decision research.


Assuntos
Envelhecimento , Motivação , Humanos , Idoso , Adulto , Probabilidade , Afeto , Tomada de Decisões , Assunção de Riscos
4.
Psychol Aging ; 37(3): 298-306, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34793191

RESUMO

Numeracy, the ability to understand and use basic probability and numerical concepts, is associated with diverse positive outcomes across the lifespan. Prior cross-sectional research on numeracy has generally found a negative association with age, but positive correlations with male gender, education attainment, and measures of fluid and crystallized intelligence have been more robust. Age effects on cognitive functioning are well established, but little is known about longitudinal trends of numeracy into older age. The present study investigates longitudinal age effects on numeracy using a sample of 524 adults (2008 Agerange = 20-78) from the RAND American Life Panel. Participants completed a numeracy measure in both 2008 and 2019, a span of 11 years. Using a linear mixed-effect model to predict numeracy scores, a significant interaction between the year of testing and the quadric age term shows a decline in numeracy scores beginning in later middle age, a trend that falls in between those previously found for crystallized and fluid cognitive abilities. Numeracy declines are somewhat mitigated for males and those with higher education, but the interaction of the two variables did not return a clear pattern of results. Prior research has shown that numeracy is positively related to the quality of health and financial decisions and, ultimately, more positive health and economic outcomes. The implications of age declines in numeracy are discussed in relation to health and financial decision-making, tasks that remain relevant into old age. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Envelhecimento , Tomada de Decisões , Envelhecimento/psicologia , Cognição , Estudos Transversais , Humanos , Inteligência , Masculino
5.
Psychol Aging ; 36(1): 96-107, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33705188

RESUMO

Empirical evidence suggests that self-reported prosociality and donations increase with age. The majority of this research was conducted using monetary donations as outcome measures. However, on average older adults hold a significant advantage in financial and material assets compared to younger adults, effectively lowering the subjective cost of small monetary donations. Are older adults also more prosocial when donating a nonmonetary resource that is of equal or even higher value for them compared to younger age groups? A first study (N = 160, 20-74 years) combined data from self-report measures, affective responses, and hypothetical donation decisions to compute a single prosociality factor. Conceptually replicating findings from Hubbard, Harbaugh, Srivastava, Degras, and Mayr (2016) on monetary donations, results suggest that nonmonetary prosociality also increases with age. However, these differences depended on the domain of the donation. Data from two further behavioral studies (Study 2: N = 156, 18-89 years; Study 3: N = 342, 19-88 years) that were analyzed using Bayesian statistics provided evidence that older adults are not more prosocial than younger and middle-aged adults when donating a small amount of their time (in service of a donation to charity). In summary, the three studies suggest that older adults are not consistently more likely to behave prosocially than younger or middle-aged adults in nonmonetary domains. These findings point to the importance of moving research on prosociality and aging beyond financial donations and further explore the role of resources and perceived costs of prosociality. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Altruísmo , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
6.
Br J Dev Psychol ; 39(2): 312-329, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33275312

RESUMO

Lifespan theory suggests a shift from a primary orientation towards attaining gains in young adulthood to preventing losses in older adulthood. The current research tested if this motivational shift is reflected in behavioural and emotional responses to risks in non-monetary gains and losses. Study 1 established in a sample of N = 168 younger (18-30 years) and older adults (65-79 years) that a non-monetary gambling task was experienced similarly by the age groups with respect to arousal and valence of the task, and the willingness to continue playing. In Study 2 (N = 83), differences between young (18-30 years) and older (64-85 years) adults' risk-taking in this non-monetary gambling task with mixed gambles were tested while assessing physiological responses (event-related heart rate change) to gain and loss feedback. Behavioural - but not physiological - results confirm hypotheses derived from a lifespan motivational framework regarding age-differential effects of gains and losses.


Assuntos
Jogo de Azar , Adulto , Idoso , Tomada de Decisões , Emoções , Humanos , Motivação , Adulto Jovem
7.
J Am Soc Echocardiogr ; 32(2): 267-276, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30459123

RESUMO

BACKGROUND: Cardio-oncology is a recently established discipline that focuses on the management of patients with cancer who are at risk for developing cardiovascular complications as a result of their underlying oncologic treatment. In metastatic colorectal cancer (mCRC) and metastatic renal cell carcinoma (mRCC), vascular endothelial growth factor inhibitor (VEGF-i) therapy is commonly used to improve overall survival. Although these novel anticancer drugs may lead to the development of cardiotoxicity, whether early detection of cardiac dysfunction using serial echocardiography could potentially prevent the development of heart failure in this patient population requires further study. The aim of this study was to investigate the role of two-dimensional speckle-tracking echocardiography in the detection of cardiotoxicity due to VEGF-i therapy in patients with mCRC or mRCC. METHODS: Patients with mRCC or mCRC were evaluated using serial echocardiography at baseline and 1, 3, and 6 months following VEGF-i treatment. RESULTS: A total of 40 patients (34 men; mean age, 63 ± 9 years) receiving VEGF-i therapy were prospectively recruited at two academic centers: 26 (65%) were receiving sunitinib, eight (20%) pazopanib, and six (15%) bevacizumab. The following observations were made: (1) 8% of patients developed clinically asymptomatic cancer therapeutics-related cardiac dysfunction; (2) 30% of patients developed clinically significant decreases in global longitudinal strain, a marker for early subclinical cardiac dysfunction; (3) baseline abnormalities in global longitudinal strain may identify a subset of patients at higher risk for developing cancer therapeutics-related cardiac dysfunction; and (4) new or worsening hypertension was the most common adverse cardiovascular event, afflicting nearly one third of the study population. CONCLUSIONS: Cardiac dysfunction defined by serial changes in myocardial strain assessed using two-dimensional speckle-tracking echocardiography occurs in patients undergoing treatment with VEGF-i for mCRC or mRCC, which may provide an opportunity for preventive interventions.


Assuntos
Antineoplásicos/efeitos adversos , Carcinoma de Células Renais/tratamento farmacológico , Neoplasias Colorretais/tratamento farmacológico , Ecocardiografia/métodos , Insuficiência Cardíaca/diagnóstico , Neoplasias Renais/tratamento farmacológico , Antineoplásicos/uso terapêutico , Carcinoma de Células Renais/diagnóstico , Carcinoma de Células Renais/secundário , Cardiotoxicidade , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/secundário , Feminino , Seguimentos , Insuficiência Cardíaca/induzido quimicamente , Humanos , Neoplasias Renais/patologia , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Prognóstico , Estudos Prospectivos , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Função Ventricular Esquerda/efeitos dos fármacos
8.
J Exp Psychol Learn Mem Cogn ; 45(7): 1166-1176, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30024260

RESUMO

Categorical perception (CP) effects manifest as faster or more accurate discrimination between objects that come from different categories compared with objects that come from the same category, controlling for the physical differences between the objects. The most popular explanations of CP effects have relied on perceptual warping causing stimuli near a category boundary to appear more similar to stimuli within their own category and/or less similar to stimuli from other categories. Hanley and Roberson (2011), on the basis of a pattern not previously noticed in CP experiments, proposed an explanation of CP effects that relies not on perceptual warping, but instead on inconsistent usage of category labels. Experiments 1 and 2 in this article show a pattern opposite the one Hanley and Roberson pointed out. Experiment 3, using the same stimuli but with different choice statistics (i.e., different probabilities of each face being the target), obtains the same pattern as the one Hanley and Roberson showed. Simulations show that both category label and perceptual models are able to reproduce the patterns of results from both experiments, provided they include information about the choice statistics. This suggests 2 conclusions. First, the results described by Hanley and Roberson should not be taken as evidence in favor of a category label model. Second, given that participants did not receive feedback on their choices, there must be some mechanism by which participants monitor their own choices and adapt to the choice statistics present in the experiment. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Formação de Conceito/fisiologia , Reconhecimento Facial/fisiologia , Modelos Psicológicos , Adulto , Humanos
9.
Gerontology ; 64(5): 475-484, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29621760

RESUMO

BACKGROUND: Older adults are stereotypically considered to be risk averse compared to younger age groups, although meta-analyses on age and the influence of gain/loss framing on risky choices have not found empirical evidence for age differences in risk-taking. OBJECTIVE: The current study extends the investigation of age differences in risk preference by including analyses on the effect of the probability of a risky option on choices in gain versus loss situations. METHODS: Participants (n = 130 adults aged 19-80 years) chose between a certain option and a risky option of varying probability in gain- and loss-framed gambles with actual monetary outcomes. RESULTS: Only younger adults displayed an overall framing effect. Younger and older adults responded differently to probability fluctuations depending on the framing condition. Older adults were more likely to choose the risky option as the likelihood of avoiding a larger loss increased and as the likelihood of a larger gain decreased. Younger adults responded with the opposite pattern: they were more likely to choose the risky option as the likelihood of a larger gain increased and as the likelihood of avoiding a (slightly) larger loss decreased. CONCLUSION: Results suggest that older adults are more willing to select a risky option when it increases the likelihood that larger losses be avoided, whereas younger adults are more willing to select a risky option when it allows for slightly larger gains. This finding supports expectations based on theoretical accounts of goal orientation shifting away from securing gains in younger adulthood towards maintenance and avoiding losses in older adulthood. Findings are also discussed in respect to the affective enhancement perspective and socioemotional selectivity theory.


Assuntos
Envelhecimento/psicologia , Tomada de Decisões , Adulto , Idoso , Idoso de 80 Anos ou mais , Comportamento de Escolha , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Psicológicos , Probabilidade , Assunção de Riscos , Inquéritos e Questionários , Adulto Jovem
10.
Accid Anal Prev ; 106: 505-514, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27567729

RESUMO

Due to their disproportional representation in fatal crashes, younger and older drivers both stand to benefit from in-vehicle safety technologies, yet little is known about how they value such technologies, or their willingness to adopt them. The current study investigated older (aged 65 and greater; N=49) and younger (ages 18-23; N=40) adults' valuation of a blind spot monitor and asked if self-reported visual difficulties while driving predicted the amount participants were willing to pay for a particular system (BMW's Active Blind Spot Detection System) that was demonstrated using a short video. Large and small anchor values ($250 and $500, respectively) were used as between subjects manipulations to examine the effects of initial valuation, and participants proceeded through a short staircase procedure that offered them either the free installation of the system on their current vehicle or a monetary prize ($25-$950) that changed in value according to which option they had selected in the previous step of the staircase procedure. Willingness to use other advanced driver assistance systems (lane-departure warning, automatic lane centering, emergency braking, adaptive cruise control, and self-parking systems) was also analyzed, additionally controlling for prior familiarity of those systems. Results showed that increased age was associated with a higher valuation for the Active Blind Spot Detection System in both the large and small anchor value conditions controlling for income, gender, and technology self-efficacy. Older adults valued blind spot detection about twice as much ($762) as younger adults ($383) in the large anchor condition, though both groups' values were in the range for the current cost of an aftermarket system. Similarly, age was the most robust positive predictor of willingness to adopt other driving technologies, along with system familiarity. Difficulties with driving-related visual factors also positively predicting acceptance levels for adaptive cruise control and emergency braking systems. Results are discussed in comparison to older adults' willingness to pay for other home-based assistive technologies aimed at improving well-being and independence.


Assuntos
Condução de Veículo/psicologia , Equipamentos de Proteção/economia , Tecnologia/economia , Acidentes de Trânsito/prevenção & controle , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Tomada de Decisões , Feminino , Humanos , Masculino , Equipamentos de Proteção/estatística & dados numéricos , Autorrelato , Adulto Jovem
11.
Can J Cardiol ; 32(12): 1513-1519, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27650929

RESUMO

BACKGROUND: In the breast cancer setting, anticancer therapies including doxorubicin (DOX) and trastuzumab (TRZ) are associated with a significantly increased risk of cardiotoxicity. Despite the increasing support for the role of oxidative stress (OS) in its pathophysiology, we still do not have an optimal antioxidant for the prevention of DOX + TRZ-mediated cardiac dysfunction. The objective of this study was to investigate whether the novel antioxidant N-acetylcysteine amide (NACA) can attenuate DOX + TRZ-induced heart failure in a murine model. METHODS: A total of 100 C57Bl/6 female mice received 1 of the following drug regimens: (1) saline, (2) NACA, (3) DOX, (4) TRZ, (5) DOX + TRZ, (6) NACA + DOX, (7) NACA + TRZ, and (8) NACA + DOX + TRZ. Serial echocardiography was performed over a 10-day study period, after which the mice were killed for histologic and biochemical analyses. RESULTS: In mice receiving DOX, the left ventricular ejection fraction (LVEF) decreased from 73% ± 4% to 43% ± 2% on day 10. In mice receiving DOX + TRZ, the LVEF decreased from 72% ± 3% to 32% ± 2% on day 10. Prophylactic administration of NACA to mice receiving DOX or DOX + TRZ was cardioprotective, with an LVEF of 62% ± 3% and 55% ± 3% on day 10, respectively. Histologic and biochemical analyses demonstrated a loss of cellular integrity, increased OS, and increased cardiac apoptosis in mice treated with DOX + TRZ, which was attenuated by the prophylactic administration of NACA. CONCLUSIONS: NACA attenuated the cardiotoxic side effects of DOX + TRZ in a murine model of chemotherapy-induced cardiac dysfunction by decreasing OS and apoptosis.


Assuntos
Acetilcisteína/análogos & derivados , Cardiotoxicidade , Doxorrubicina/efeitos adversos , Trastuzumab/efeitos adversos , Acetilcisteína/farmacologia , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antioxidantes/farmacologia , Cardiotônicos/farmacologia , Cardiotoxicidade/diagnóstico , Cardiotoxicidade/etiologia , Cardiotoxicidade/prevenção & controle , Modelos Animais de Doenças , Doxorrubicina/administração & dosagem , Monitoramento de Medicamentos , Ecocardiografia/métodos , Feminino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Trastuzumab/administração & dosagem , Resultado do Tratamento
12.
Gerontechnology ; 15(4): 233-242, 2016 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-29033700

RESUMO

Healthcare delivered at home via telehealth technology may save on both individual and societal healthcare costs. Three studies investigated potential attitudinal barriers to home healthcare adoption. Results from the first concerning adults' privacy concerns and mobile device preferences showed that attitudes clustered into 4 factors and that older adults, particularly males, showed less concern than younger adults about privacy. The second and third studies explored comfort with a wearable device and the role of aesthetics over 2-week and 6-month intervals. Results showed that older adults had stable ratings for comfort while wearing a watch device designed to collect data in real time and that aspects of physical comfort predicted use over a six-month time period. Taken together, the studies provide evidence that attitudes about privacy and comfort for wearable health devices are unlikely to be significant barriers to adoption, though first impressions are important for all age groups.

13.
Psychol Aging ; 30(3): 688-98, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26098168

RESUMO

The framing of decision scenarios in terms of potential gains versus losses has been shown to influence choice preferences between sure and risky options. Normative cognitive changes associated with aging have been known to affect decision making, which has led to a number of studies investigating the influence of aging on the effect of framing. Mata, Josef, Samanez-Larkin, and Hertwig (2011) systematically reviewed the available literature using a meta-analytic approach, but did not include tests of homogeneity or subsequent moderator variable analyses. The current review serves to extend the previous analysis to include such tests as well as update the pool of studies available for analysis. Results for both positively and negatively framed conditions were reviewed using 2 meta-analyses encompassing data collected from 3,232 subjects across 18 studies. Deviating from the previous results, the current analysis found a tendency for younger adults to choose the risky option more often than older adults for positively framed items. Moderator variable analyses found this effect likely to be driven by the specific decision scenario, showing a significant effect, with younger adults choosing the risky option more often in small-amount financial and large-amount mortality-based scenarios. For negatively framed items, the current review found no overall age difference in risky decision making, confirming the results from the prior meta-analysis. Moderator variable analyses conducted to address heterogeneity found younger adults to be more likely than older adults to choose the risky option for negatively framed high-amount mortality-based decision scenarios. Practical implications for older adults are discussed.


Assuntos
Envelhecimento/psicologia , Comportamento de Escolha , Assunção de Riscos , Humanos , Pessoa de Meia-Idade , Risco , Adulto Jovem
14.
Hum Asp IT Aged Popul (2015) ; 9194: 3-14, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31240277

RESUMO

OBJECTIVES: To investigate the relationship between an older individual's self-reported health and the perceived usefulness of computers in assisting with health-related tasks. METHODS: A total of 210 older adults (age≥60) completed questionnaire items pertaining to demographics, general health, perception of importance of daily activities, technology experience and use, and perceived usefulness of computers and the Internet. Results were obtained using a factor analysis and multiple regression. RESULTS: Self-reported health was found to have a significant negative relationship with the importance of health-related activities to daily living (Beta = -0.210) but a significant positive relationship with the perceived usefulness of computers in assisting with the same health-related activities (Beta = 0.151). DISCUSSION: Results indicate that adoption of health-supporting technologies could be facilitated by user-centered designs that better accommodate older adults in poor health. Alternatively, adoption may be facilitated by making the potential usefulness of computers more salient to older adults.

15.
J Gerontol Nurs ; 41(4): 47-56, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25486115

RESUMO

Home telehealth (HT) refers to the use of videoconferencing to provide care to patients remotely and can help older adults age in place. However, these technologies are unlikely to impact care unless health care providers are motivated to use them. Education may play a key role in increasing motivation to use and competence regarding HT. To help guide the development of nursing education to facilitate adoption and use, the current study examined predictors of Dutch nurses' willingness to use HT, based on a survey of 67 Dutch nurses with and 126 without HT experience. Nurses' willingness to use this technology was predicted by HT's (a) perceived usefulness to the client, (b) effort expectancy, (c) social influence, and (d) cost expectations. These observed relationships are anticipated to help with the development of effective educational programs to increase HT use and, therefore, improve older adults' quality of life. [Journal of Gerontological Nursing, 41(4), 47-56.].


Assuntos
Atitude Frente aos Computadores , Enfermagem Geriátrica/organização & administração , Conhecimentos, Atitudes e Prática em Saúde , Serviços de Assistência Domiciliar/organização & administração , Enfermeiras e Enfermeiros/estatística & dados numéricos , Telemedicina/estatística & dados numéricos , Comunicação por Videoconferência/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Competência Clínica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Países Baixos
16.
Plast Reconstr Surg ; 135(1): 124e-134e, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25539319

RESUMO

BACKGROUND: Radiation therapy results in permanent damage to the microvasculature, leading to dermal damage and inelasticity in normal tissues. Deferoxamine is a U.S. Food and Drug Administration-approved iron-chelating medication that has also been shown to increase angiogenesis. The authors hypothesize that the application of deferoxamine will result in increased vascularity and improved tissue elasticity in a rat irradiated transverse rectus abdominis musculocutaneous flap model. METHODS: Fifteen rats underwent a transverse rectus abdominis myocutaneous flap and were randomized to three groups: control, radiation therapy, and radiation therapy plus deferoxamine. The flaps in the radiation therapy and radiation therapy plus deferoxamine groups were irradiated with 35 Gy in a single dose. Four weeks after irradiation, rats in the radiation therapy plus deferoxamine group were treated with deferoxamine. Flaps were imaged with micro-computed tomographic angiography. Flap creep and stress relaxation were assessed using a tensiometer. Hematoxylin and eosin, picrosirius red, and Verhoeff-van Gieson staining was performed. RESULTS: Irradiated flaps demonstrated gross stigmata of cutaneous radiation injury within 4 weeks. Histologically, the epidermis in the radiation therapy flaps was found to be thicker than in the radiation therapy plus deferoxamine and control flaps (p < 0.001). Micro-computed tomographic angiography demonstrated a statistically significant (p < 0.05) increase in vascularity in the radiation therapy plus deferoxamine flaps compared with radiation therapy alone. The creep curve was indicative of increased elasticity in the radiation therapy plus deferoxamine flaps compared with radiation therapy flaps. CONCLUSION: Deferoxamine appears to mitigate radiation-induced hypovascularity and improve tissue elasticity in a rat model of soft-tissue reconstruction.


Assuntos
Desferroxamina/uso terapêutico , Lesões por Radiação/tratamento farmacológico , Retalhos Cirúrgicos , Animais , Modelos Animais de Doenças , Masculino , Ratos , Ratos Sprague-Dawley , Reto do Abdome/transplante
17.
J Appl Clin Med Phys ; 15(4): 4801, 2014 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-25207408

RESUMO

Recently, the developers of Eclipse have recommended the use of ionization chambers for all profile scanning, including for the modeling of VMAT and stereotactic applications. The purpose of this study is to show the clinical impact caused by the choice of detector with respect to its ability to accurately measure dose in the penumbra and tail regions of a scanned profile. Using scan data acquired with several detectors, including an IBA CC13, a PTW 60012, and a Sun Nuclear EDGE Detector, three complete beam models are created, one for each respective detector. Next, using each beam model, dose volumes are retrospectively recalculated from actual anonymous patient plans. These plans include three full-arc VMAT prostate plans, three left chest wall plans delivered using irregular compensators, two half-arc VMAT lung plans, three MLC-collimated static-field pairs, and two SBRT liver plans. Finally, plans are reweighted to deliver the same number of monitor units, and mean dose-to-target volumes and organs at risk are calculated and compared. Penumbra width did not play a role. Dose in the tail region of the profile made the largest difference. By overresponding in the tail region of the profile, the 60012 diode detector scan data affected the beam model in such a way that target doses were reduced by as much as 0.4% (in comparison to CC13 and EDGE data). This overresponse also resulted in an overestimation of dose to peripheral critical structure, whose dose consisted mainly of scatter. This study shows that, for modeling the 6 MV beam of Acuros XB in Eclipse Version 11, the choice to use a CC13 scanning ion chamber or an EDGE Detector was an unimportant choice, providing nearly identical models in the treatment planning system.


Assuntos
Neoplasias Hepáticas/cirurgia , Neoplasias Pulmonares/radioterapia , Aceleradores de Partículas/instrumentação , Neoplasias da Próstata/radioterapia , Radiometria/instrumentação , Radiocirurgia , Radioterapia de Intensidade Modulada , Algoritmos , Humanos , Masculino , Órgãos em Risco , Dosagem Radioterapêutica , Estudos Retrospectivos
18.
Radiat Oncol ; 9: 164, 2014 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-25059785

RESUMO

PURPOSE: This study was designed to evaluate the dosimetric feasibility of definitive stereotactic body radiation therapy (SBRT) for the treatment of medically inoperable early stage endometrial cancer. METHODS: CT simulation scans from 10 medically inoperable early stage endometrial cancer patients previously treated with high dose-rate (HDR) intracavitary brachytherapy were used to generate Helical Tomotherapy (HT) plans using the IMRT mode with clinical target volumes (CTVs) that included the uterus plus cervix. A prescription dose of 34 Gy in 4 fractions was used. The SBRT dosimetry was compared to the 10 prior intracavitary brachytherapy plans normalized to a standard dose. Organs at risk (OARs) evaluated were the bladder, rectum, sigmoid, femoral heads, and other bowel, including both large and small bowel. The simulation CT and daily image guidance for 4 patients treated with this technique were evaluated to assess for interfraction variation in the uterine position and effects on dosimetry. RESULTS: Compared to intracavitary brachytherapy, HT SBRT produced significantly greater overall target coverage to the uterus, boost CTV, and PTV, with exception of the V150% of the uterus. HT SBRT significantly increased dose to the rectum, bowel, and femoral heads compared to intracavitary brachytherapy, though not outside of dose tolerance limits. Review of daily image guidance for patients treated with this technique demonstrated good reproducibility with a mean overlap index of 0.87 (range, 0.74 - 0.99). CONCLUSIONS: Definitive SBRT for medically inoperable early stage endometrial cancer appears to be a feasible treatment option. Future studies are warranted to evaluate long-term clinical outcomes with this technique, compared to HDR intracavitary brachytherapy.


Assuntos
Braquiterapia , Neoplasias do Endométrio/radioterapia , Neoplasias do Endométrio/cirurgia , Radiocirurgia , Simulação por Computador , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Estadiamento de Neoplasias , Órgãos em Risco , Prognóstico , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Reprodutibilidade dos Testes , Tomografia Computadorizada por Raios X
20.
J Appl Clin Med Phys ; 13(4): 3613, 2012 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-22766940

RESUMO

Magnetic resonance imaging (MRI) is regularly used for stereotactic imaging of Gamma Knife (GK) radiosurgery patients for GK treatment planning. MRI-induced thermal injuries have occurred and been reported for GK patients with attached metallic headframes. Depending on the specific MR imaging and headframe conditions, a skin injury from MRI-induced heating can potentially occur where the four headframe screws contact the skin surface of the patient's head. Higher MR field strength has a greater heating potential. Two primary heating mechanisms, electromagnetic induction and the antenna effect, are possible. In this study, MRI-induced heating from a 3T clinical MRI scanner was investigated for stereotactic headframes used in gamma radiosurgery and neurosurgery. Using melons as head phantoms, optical thermometers were used to characterize the temperature profile at various points of the melon headframe composite as a function of two 3T MR pulse sequence protocols. Different combinations of GK radiosurgery headframe post and screw designs were tested to determine best and worst combinations for MRI-induced heating. Temperature increases were measured for all pulse sequences tested, indicating that the potential exists for MRI-induced skin heating and burns at the headframe attachment site. This heating originates with electromagnetic induction caused by the RF fields inducing current in a loop formed by the headframe, mounting screws, and the region of the patient's head located between any of the two screws. This induced current is then resistively dissipated, with the regions of highest resistance, located at the headframe screw-patient head interface, experiencing the most heating. Significant heating can be prevented by replacing the metallic threads holding the screw with electrically insulated nuts, which is the heating prevention and patient safety recommendation of the GK manufacturer. Our results confirm that the manufacturer's recommendation to use insulating nuts reduces the induced currents in the headframe nearly to zero, effectively preventing heating and minimizing the likelihood of thermal injury.


Assuntos
Queimaduras/prevenção & controle , Raios gama , Imageamento por Ressonância Magnética , Radiocirurgia/efeitos adversos , Pele/lesões , Queimaduras/etiologia , Humanos , Imageamento por Ressonância Magnética/instrumentação , Segurança do Paciente , Imagens de Fantasmas , Doses de Radiação , Ondas de Rádio , Radiocirurgia/métodos , Temperatura
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