Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Med Sci Sports Exerc ; 55(12): 2132-2142, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37436930

RESUMO

PURPOSE: Triple-negative breast cancer (TNBC) is an aggressive, highly metastatic malignancy with high recurrence rates. Hypoxia is a hallmark of the TNBC tumor microenvironment, which promotes tumor growth while impairing natural killer (NK) cell cytotoxic functions. Although acute exercise improves NK cell function under normoxic conditions, the effect of exercise on NK cell cytotoxic functions under hypoxic conditions mimicking O 2 tensions observed in solid tumors is unknown. METHODS: The cytotoxic functions of resting and postexercise NK cells isolated from thirteen young inactive healthy women were assessed against breast cancer cells expressing different levels of hormone receptors (MCF-7 and MDA-MB-231) under normoxic and hypoxic conditions. Mitochondrial respiration and H 2 O 2 efflux rates of the TNBC-activated NK cells were assessed via high-resolution respirometry. RESULTS: Under hypoxia, postexercise NK cells exhibited greater killing of TNBC than resting NK cells. Further, postexercise NK cells were more likely to kill TNBC under hypoxia than normoxic conditions. In addition, mitochondrial respiration associated with oxidative (OXPHOS) capacity of TNBC-activated NK cells was greater in postexercise cells than resting cells under normoxia, but not under hypoxia. Finally, acute exercise was associated with reduced mitochondrial H 2 O 2 efflux by NK cells in both conditions. CONCLUSIONS: Together, we present crucial interrelationships between hypoxia and exercise-induced changes in NK cell functions against TNBC cells. By modulating their mitochondrial bioenergetic functions, we postulate that acute exercise improves NK cell function under hypoxic conditions. Specifically, NK cell O 2 and H 2 O 2 flow (pmol·s -1 ·million NK cells -1 ) changes in response to 30-min cycling suggest that exercise primes NK cell tumor killing by reducing mitochondrial oxidative stress and, thus, rescuing their function when exposed to harsh hypoxic environments as observed in the microenvironment of breast solid tumors.


Assuntos
Antineoplásicos , Neoplasias de Mama Triplo Negativas , Humanos , Feminino , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Linhagem Celular Tumoral , Células Matadoras Naturais/patologia , Hipóxia , Antineoplásicos/farmacologia , Respiração , Exercício Físico , Microambiente Tumoral
2.
J Infect Prev ; 24(3): 103-112, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37051306

RESUMO

Background: Effective health communication is crucial for achieving positive population health outcomes. This is important for infection prevention and control (IPC), which relies on widespread public compliance to be effective. Whilst social media (SM) platforms disseminate health information, there is conflicting evidence to suggest their influence on compliance with public health guidelines. Objective: To appraise the available evidence and determine the extent to which social media exposure contributes to public compliance with IPC measures. Methods: A systematic protocol based on the MOOSE and PRISMA guidelines was followed. Observational studies were identified through systematic searches of four electronic databases and a hand search. Following data extraction, eligible studies were quality assessed, and the findings were integrated using narrative synthesis. Findings: 15 studies were included. The studies located presented heterogeneous designs and findings. A weak positive association was identified, with 60% of the studies observing a positive association between social media and compliance with IPC measures. 26.7% identified a negative correlation, and 13.3% identified no correlation. Several factors were identified to mediate the relationship, including knowledge and conspiracy beliefs. Discussion: This systematic review identified a weak positive correlation between exposure to social media and public compliance with recommended IPC measures, suggesting that social media should be utilised in future IPC related communication strategies. Social media provides a cost-effective, publicly accessible platform to disseminate accurate information, and neutralise misinformation. Recommendations are made for further research to reduce the uncertainty created by the identification of heterogenous studies.

3.
Sensors (Basel) ; 23(8)2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-37112473

RESUMO

Aging is a significant contributor to changes in sleep patterns, which has compounding consequences on cognitive health. A modifiable factor contributing to poor sleep is inadequate and/or mistimed light exposure. However, methods to reliably and continuously collect light levels long-term in the home, a necessity for informing clinical guidance, are not well established. We explored the feasibility and acceptability of remote deployment and the fidelity of long-term data collection for both light levels and sleep within participants' homes. The original TWLITE study utilized a whole-home tunable lighting system, while the current project is an observational study of the light environment already existing in the home. This was a longitudinal, observational, prospective pilot study involving light sensors remotely deployed in the homes of healthy adults (n = 16, mean age: 71.7 years, standard deviation: 5.0 years) who were co-enrolled in the existing Collaborative Aging (in Place) Research Using Technology (CART) sub-study within the Oregon Center for Aging and Technology (ORCATECH). For 12 weeks, light levels were recorded via light sensors (ActiWatch Spectrum), nightly sleep metrics were recorded via mattress-based sensors, and daily activity was recorded via wrist-based actigraphy. Feasibility and acceptability outcomes indicated that participants found the equipment easy to use and unobtrusive. This proof-of-concept, feasibility/acceptability study provides evidence that light sensors can be remotely deployed to assess relationships between light exposure and sleep among older adults, paving the way for measurement of light levels in future studies examining lighting interventions to improve sleep.


Assuntos
Atividades Cotidianas , Vida Independente , Humanos , Idoso , Estudos Prospectivos , Projetos Piloto , Tecnologia de Sensoriamento Remoto/métodos
4.
Clin Gerontol ; 46(5): 759-766, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36208222

RESUMO

OBJECTIVES: We aimed to examine the impact of COVID-19 pandemic-related stay-at-home orders on weekly reports of mood and activity before and during COVID-19 in a sample of older Veterans and their cohabitants. METHODS: Urban and rural Veterans and their cohabitants living in the Pacific Northwest ≥62 years old were enrolled as part of the Collaborative Aging Research Using Technology initiative (n = 100, age = 71.2 ± 6.5, 41% women). Participants reported frequency of social activities (e.g., travel away), physical illness, and mood (blue mood and loneliness) via weekly online health forms. RESULTS: A total of 2,441 weekly online health forms (OHFs) were collected from 100 participants. During the COVID-19 pandemic, blue mood (OR = 4.4, p < .0001) and loneliness (OR = 7.2, p < .0001) were significantly higher than before the pandemic, and travel away from home was significantly lower (OR = 0.5, p < .0001). Prevalence of blue mood and loneliness were not associated with rurality. CONCLUSIONS: The current study established that blue mood and loneliness were significantly more prevalent in older Veterans following COVID-19 stay-at-home orders regardless of rurality. CLINICAL IMPLICATIONS: The COVID-19 pandemic associated health precautions, while necessary to curb acute health risks, have created a unique situation that places vulnerable populations at increased risk of low mood.

5.
J Veterans Stud ; 9(3): 98-102, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38390452

RESUMO

The objective of this study was to explore aging veteran's military experiences, including serving in conflicts or wars and their military-related health issues, with a focus on the impacts of their experiences on the aging process. A cohort of 48 Pacific Northwest, primarily rural, Vietnam-era veterans responded to a survey questionnaire emailed in 2021. The main survey question addressed in this article is, "Do you believe that your military experience has made aging more difficult?" Fifty percent of this cohort served in a conflict or war, mostly in Vietnam, and 68% reported having military-related health issues. We used veterans' survey responses to create this article which is a hybrid narrative-a mix of poetry and prose. Regardless of serving in conflicts or wars and their military-related health issues, most veterans found a silver lining of service that acts as a source of pride and resilience that is beneficial to post-military life as they age.

6.
J Neuropathol Exp Neurol ; 82(1): 57-70, 2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-36343095

RESUMO

Postmortem (PM) magnetic resonance imaging (MRI) can serve as a bridge between in vivo imaging and histology by connecting MRI observed macrostructural findings to histological staining and microstructural changes. Data were acquired from 20 formalin-fixed brains including T2, T1, PD, and T2*-weighted images of left hemispheres and 6-mm-thick coronal slices. Tissue slices were bisected, aligned to MR images and used to guide histological sampling. Markers of myelin and oligodendroglia alterations were semiquantitatively rated and compared within white matter hyperintensities (WMHs) and normal-appearing white matter. Tissue priors were created from 3T in vivo data and used to guide segmentation of WMH. PM WMH and hemisphere volumes were compared to volumes derived from in vivo data. PM T2 WMH and T1 hemisphere volumes were correlated with in vivo 3T FLAIR WMH and T1 hemisphere volumes. WMH showed significant myelin loss, decreased GFAP expression and increased vimentin expression. MR-visible perivascular spaces and cortical microvascular lesions were successfully captured on histopathological sections. PM MRI can quantify cerebrovascular disease burden and guide tissue sampling, allowing for more comprehensive characterization of cerebrovascular disease that may be used to study etiologies of age-related cognitive change.


Assuntos
Transtornos Cerebrovasculares , Substância Branca , Humanos , Encéfalo/patologia , Imageamento por Ressonância Magnética/métodos , Transtornos Cerebrovasculares/patologia , Substância Branca/patologia , Bainha de Mielina
7.
Acad Med ; 97(8): 1160-1163, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35917543

RESUMO

PROBLEM: Students eager to enter the medical field must develop perspective-taking skills that enhance their ability to connect with patients. Toward this goal, the authors developed a pilot workshop for undergraduate students that included an art activity during which they collaborated to design scalp tattoos to symbolize cancer patients' experiences with chemotherapy and hair loss. APPROACH: A 90-minute, arts-based workshop was held in April 2019. One author selected anonymous excerpts from previously conducted interviews with patients experiencing ovarian and uterine cancer. These excerpts were shared with students to humanize patients' perspectives and give context to the difficulty of coping with chemotherapy-induced alopecia. Students discussed these excerpts and images of scalp tattoos from the internet. Together, they then designed scalp tattoos representing their perspective on the experience of coping with chemotherapy and hair loss and drew them onto mannequin heads. OUTCOMES: Twenty members of the university community participated in this workshop, including 3 faculty members and 17 undergraduate students. Participants worked together to create 2 sets of scalp tattoos. Of the 20 participants, 75% (n = 15) responded to the postworkshop survey. All respondents were undergraduate students, and 73% (n = 11) reported an increase in empathy toward patients and 87% (n = 13) an increased connection with the patient experience. All respondents agreed that the art activity demonstrated the importance of taking the patient's perspective. NEXT STEPS: This arts-based workshop is effective and can be replicated for other audiences, including undergraduate students, medical students, and practicing clinicians, to encourage perspective-taking and compassion for patients. Further analysis of students' skill development using pre- and postworkshop data is needed.


Assuntos
Neoplasias , Estudantes de Medicina , Tatuagem , Alopecia/induzido quimicamente , Humanos , Neoplasias/tratamento farmacológico , Couro Cabeludo , Tatuagem/efeitos adversos
8.
Innov Aging ; 5(4): igab036, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34761126

RESUMO

[This corrects the article DOI: 10.1093/geroni/igaa066.].

9.
Innov Aging ; 5(1): igaa066, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33718627

RESUMO

BACKGROUND AND OBJECTIVES: Many older adults remain inactive despite the known positive health implications of physical activity (improved mood, reduced mortality risk). Physical inactivity is an interdependent phenomenon in couples, but most research examines physical inactivity at the individual level. We estimated the average amount of prolonged physical inactivity for older adult couples and, using dyadic analysis, identified physical and mental health determinants thereof. RESEARCH DESIGN AND METHODS: Forty-six heterosexual older adult couples (age = 70.61 ± 6.56) from the Veterans Integrated Service Network 20 cohort of the Collaborative Aging Research using Technology (CART) initiative were included. The average number per day of prolonged inactive periods (no step counts or sleep activity for ≥30 min) was estimated using actigraphy data collected over a month. RESULTS: Multilevel modeling revealed that, within couples, there was no significant difference between partners in the average amount of inactive periods (p = .28). On average across couples, males and females had an average of 6.90 ± 2.02 and 6.56 ± 1.93 inactive periods per day, respectively. For males, older age was the only variable associated with more inactive periods (ß = 0.15, p = .002). For females, having more depressive symptoms in both dyad members was associated with fewer inactive periods (female: ß = -0.30, p = .03; male: ß = -0.41, p < .001), and more dependence in completing their own instrumental activities of daily living predicted more inactive periods (ß = 2.58, p < .001). DISCUSSION AND IMPLICATIONS: Viewing couples' activity as an interdependent phenomenon, rather than individual, provides a novel approach to identifying pathways to reduce inactivity in older adults, especially when focusing on the mental health and level of independence within the couple.

10.
J Alzheimers Dis ; 74(1): 65-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32176647

RESUMO

BACKGROUND: Cerebrovascular disease is a common cause of dementia in older adults, and potentially preventable with early intervention. Oxylipins are produced from the oxidation of long-chain polyunsaturated fatty acids (PUFA) possessing potent vascular effects. Oxylipins generated from the cytochrome P450 pathway are enzymatically converted to diols by soluble epoxide hydrolase (sEH); sEH products have been associated with small vessel ischemic disease. Little is known about oxylipins' impact on markers of dementia risk. OBJECTIVE: An exploratory examination of the association between omega-6 and omega-3 derived oxylipins, brain MRI, and cognition. METHODS: Thirty-seven non-demented participants with controlled hypertension (mean age 65.6 years) were enrolled in a dementia prevention study investigating fish oil and lipoic acid on preserving cognitive function. Baseline associations between plasma oxylipins, white matter hyperintensity (WMH), and Trails-B were examined using linear regression. P450-derived diol/epoxide ratio was an indirect measure of sEH activity. RESULTS: Omega-6 derived 9-HODE was associated with increased WMH (p = 0.017) and reduced grey matter volume (p = 0.02). Omega-6 P450-derived diol/epoxide ratio 9,10-DiHOME/9,10-EpOME was associated with increased WMH (p = 0.035) and poorer performance on Trails-B (p = 0.05); ratio14,15-DHET/14,15-EET was associated with increased WMH (p = 0.045). Omega-3 P450-derived diol/epoxide ratio 19,20-DiHDPE/19,20-EpDPE was associated with increased WMH (p = 0.04) and poorer performance on Trails-B (p = 0.04). Arachidonic acid was associated with better performance on Trails-B (p = 0.012); Omega-3 derived 16,17-EpDPE was associated with decreased WMH (p = 0.005). CONCLUSIONS: With the exception of arachidonic acid, it was specific oxylipin products, not their parent PUFAs, that were associated with unfavorable and favorable MRI and cognitive markers of dementia risk.


Assuntos
Cognição/efeitos dos fármacos , Função Executiva , Ácidos Graxos Ômega-3/química , Ácidos Graxos Ômega-6/química , Hipertensão/diagnóstico por imagem , Hipertensão/psicologia , Oxilipinas/efeitos adversos , Substância Branca/diagnóstico por imagem , Idoso , Encéfalo/diagnóstico por imagem , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor/efeitos dos fármacos , Teste de Sequência Alfanumérica
11.
Digit Biomark ; 4(Suppl 1): 100-118, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33442584

RESUMO

INTRODUCTION: Future digital health research hinges on methodologies to conduct remote clinical assessments and in-home monitoring. The Collaborative Aging Research Using Technology (CART) initiative was introduced to establish a digital technology research platform that could widely assess activity in the homes of diverse cohorts of older adults and detect meaningful change longitudinally. This paper reports on the built end-to-end design of the CART platform, its functionality, and the resulting research capabilities. METHODS: CART platform development followed a principled design process aiming for scalability, use case flexibility, longevity, and data privacy protection while allowing sharability. The platform, comprising ambient technology, wearables, and other sensors, was deployed in participants' homes to provide continuous, long-term (months to years), and ecologically valid data. Data gathered from CART homes were sent securely to a research server for analysis and future data sharing. RESULTS: The CART system was created, iteratively tested, and deployed to 232 homes representing four diverse cohorts (African American, Latinx, low-income, and predominantly rural-residing veterans) of older adults (n = 301) across the USA. Multiple measurements of wellness such as cognition (e.g., mean daily computer use time = 160-169 min), physical mobility (e.g., mean daily transitions between rooms = 96-155), sleep (e.g., mean nightly sleep duration = 6.3-7.4 h), and level of social engagement (e.g., reports of overnight visitors = 15-45%) were collected across cohorts. CONCLUSION: The CART initiative resulted in a minimally obtrusive digital health-enabled system that met the design principles while allowing for data capture over extended periods and can be widely used by the research community. The ability to monitor and manage health digitally within the homes of older adults is an important alternative to in-person assessments in many research contexts. Further advances will come with wider, shared use of the CART system in additional settings, within different disease contexts, and by diverse research teams.

12.
Handb Clin Neurol ; 158: 153-162, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30482343

RESUMO

Changes in mood, emotions, and behavior are common components of the acute clinical picture of sport-related concussion (SRC). Common concussion symptom inventories such as the Sport Concussion Assessment Tool-5 (SCAT5) contain a large number of questions that assess these neuropsychiatric domains. In fact, of 22 items assessed by the SCAT5, arguably only five of the items do not overlap with symptoms assessed by standard measures of anxiety and depression, suggesting that concussion is best viewed as a neuropsychiatric syndrome. Furthermore, it is important to understand the complex relationship between preinjury psychologic health, acute injury symptom profile, and the role that changes in mood, emotions, and behavior play in the recovery trajectory after concussion. Some research suggests that there may also be long-term neuropsychiatric effects of concussion, repetitive concussion, and repetitive head impacts. This chapter provides a review of the neuropsychiatric sequelae of acute SRC, the current evidence for long-term neuropsychiatric effects of repetitive concussion, and the impact of neuropsychiatric symptoms on recovery trajectory. Clinical principles relevant to management are described.


Assuntos
Traumatismos em Atletas/complicações , Concussão Encefálica/complicações , Concussão Encefálica/etiologia , Transtornos Mentais/etiologia , Humanos , Transtornos Mentais/diagnóstico por imagem , Testes Neuropsicológicos
13.
Br J Sports Med ; 51(12): 919-929, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28455364

RESUMO

OBJECTIVE: To conduct a systematic review of published literature on advanced neuroimaging, fluid biomarkers and genetic testing in the assessment of sport-related concussion (SRC). DATA SOURCES: Computerised searches of Medline, PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, Scopus and Cochrane Library from 1 January 2000 to 31 December 2016 were done. There were 3222 articles identified. STUDY SELECTION: In addition to medical subject heading terms, a study was included if (1) published in English, (2) represented original research, (3) involved human research, (4) pertained to SRC and (5) involved data from neuroimaging, fluid biomarkers or genetic testing collected within 6 months of injury. Ninety-eight studies qualified for review (76 neuroimaging, 16 biomarkers and 6 genetic testing). DATA EXTRACTION: Separate reviews were conducted for neuroimaging, biomarkers and genetic testing. A standardised data extraction tool was used to document study design, population, tests employed and key findings. Reviewers used a modified quality assessment of studies of diagnostic accuracy studies (QUADAS-2) tool to rate the risk of bias, and a modified Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to rate the overall level of evidence for each search. DATA SYNTHESIS: Results from the three respective reviews are compiled in separate tables and an interpretive summary of the findings is provided. CONCLUSIONS: Advanced neuroimaging, fluid biomarkers and genetic testing are important research tools, but require further validation to determine their ultimate clinical utility in the evaluation of SRC. Future research efforts should address current gaps that limit clinical translation. Ultimately, research on neurobiological and genetic aspects of SRC is predicted to have major translational significance to evidence-based approaches to clinical management of SRC, much like applied clinical research has had over the past 20 years.


Assuntos
Traumatismos em Atletas/diagnóstico , Biomarcadores , Concussão Encefálica/diagnóstico , Testes Genéticos , Neuroimagem , Humanos , Esportes
14.
Neuropsychopharmacology ; 42(9): 1766-1775, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27874023

RESUMO

The purpose of this multicenter, prospective, randomized, placebo-controlled study was to evaluate and compare the efficacy of two cognitive rehabilitation interventions (Memory and Attention Adaptation Training (MAAT) and Attention Builders Training (ABT)), with and without pharmacological enhancement (ie, with methylphenidate (MPH) or placebo), for treating persistent cognitive problems after traumatic brain injury (TBI). Adults with a history of TBI at least 4 months before study enrollment with either objective cognitive deficits or subjective cognitive complaints were randomized to receive MPH or placebo and MAAT or ABT, yielding four treatment combinations: MAAT/MPH (N=17), ABT/MPH (N=19), MAAT/placebo (N=17), and ABT/placebo (N=18). Assessments were conducted pre-treatment (baseline) and after 6 weeks of treatment (post treatment). Outcome measures included scores on neuropsychological measures and subjective rating scales. Statistical analyses used linear regression models to predict post-treatment scores for each outcome variable by treatment type, adjusting for relevant covariates. Statistically significant (P<0.05) treatment-related improvements in cognitive functioning were found for word-list learning (MAAT/placebo>ABT/placebo), nonverbal learning (MAAT/MPH>MAAT/placebo and MAAT/MPH>ABT/MPH), and auditory working memory and divided attention (MAAT/MPH>ABT/MPH). These results suggest that combined treatment with metacognitive rehabilitation (MAAT) and pharmacotherapy (MPH) can improve aspects of attention, episodic and working memory, and executive functioning after TBI.


Assuntos
Lesões Encefálicas Traumáticas/terapia , Estimulantes do Sistema Nervoso Central/uso terapêutico , Transtornos Cognitivos/terapia , Terapia Cognitivo-Comportamental , Metilfenidato/uso terapêutico , Adulto , Atenção/efeitos dos fármacos , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/psicologia , Transtornos Cognitivos/etiologia , Terapia Combinada , Método Duplo-Cego , Função Executiva/efeitos dos fármacos , Feminino , Humanos , Modelos Lineares , Masculino , Memória/efeitos dos fármacos , Testes Neuropsicológicos , Resultado do Tratamento
15.
Child Obes ; 8(4): 331-8, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22867072

RESUMO

BACKGROUND: Congress sought to address escalating rates of childhood obesity by mandating local wellness policies (LWP) (Child Nutrition and WIC Reauthorization Act of 2004). Previous research has examined LWP content and quality; however, data relative to LWP implementation is limited, and none has examined the relationship between LWP quality and implementation. The purpose of this study was to examine the influence of LWP strength on perceived implementation of LWP components. METHODS: Data collected from school districts in California, Iowa, and Pennsylvania included district LWPs and online surveys at the district (n = 23) and school levels (n = 76). LWPs were scored using a standardized coding tool. Binary and multinomial regression models were used to examine the predictive ability of covariates and independent factors on perceived implementation of reimbursable school meals and nutrition guidelines for competitive foods sold and offered. RESULTS: Overall LWP strength score did not predict perceived implementation of reimbursable school meals or nutrition guidelines for competitive foods. LWP component strength scores for reimbursable meals and nutrition guidelines did not consistently predict perceived implementation of those components. State and urban-centric locale did predict perceived implementation of some LWP components, particularly nutrition guidelines for competitive foods sold and offered. State was a particularly influential factor in the implementation of LWPs in this study, likely due to differences in state policies and laws. CONCLUSIONS: Overall LWP, reimbursable school meals, and nutrition guidelines for competitive foods strength scores do not predict perceived implementation of reimbursable school meals and nutrition guidelines for competitive foods.


Assuntos
Serviços de Alimentação/normas , Promoção da Saúde , Política Nutricional , Instituições Acadêmicas , California , Criança , Distribuidores Automáticos de Alimentos , Humanos , Iowa , Pennsylvania
16.
Talanta ; 72(1): 145-54, 2007 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-19071595

RESUMO

A highly sensitive and selective liquid chromatography-mass spectrometry (LC-MS) method has been developed for the determination of epirubicin in serum and cell specimens using daunorubicin as an internal standard. Using atmospheric pressure chemical ionisation (APCI), the epirubicin metabolites were readily distinguishable by their fragmentation pattern in the mass spectrometer. Selected reaction monitoring (SRM) mode was employed for quantitation of epirubicin and the metabolites. Following extraction, chromatography was performed on a C18 column with a mobile phase consisting of water-acetonitrile-formic acid, pH 3.2, with a flow rate of 200mul/min. The limit of detection (LOD) and the limit of quantitation (LOQ) of this method in serum were determined to be 1.0 and 2.5ng/ml, respectively. Linearity of the method was verified over the concentration range of 2.5-2000ng/ml, with a high correlation coefficient (R(2)>/=0.998). For the extraction procedure, an aliquot of 500mul serum, spiked with internal standard, was extracted using a chloroform-2-isopropanol (2:1, v/v) mixture. The method has been applied to the analysis of epirubicin in cancer cell samples and the identification of known and unknown metabolites in clinical trial patient serum samples.

18.
Talanta ; 57(6): 1119-32, 2002 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-18968718

RESUMO

A series of derivatisation reactions between p-t-butyl calix[4]arene and ethyl bromoacetate were carried out in order to prepare 1,3 diester substituted calix[4]arene. Mass spectral data, obtained from direct injection of samples, indicated that the reactions were rich in the desired product. Since the ultra violet (UV) spectra of the desired product and possible impurities are very similar, liquid chromatography (LC) chromatographic data seemed to corroborate these results. However, when on-line LC-UV-MS was carried out and each LC peak subjected to MS analysis as it eluted, a very different picture emerged. It was found that many of these reactions actually contained high levels of the monoester product which, having less affinity for sodium in the MS, is therefore seriously underestimated in any direct injection assay. LC-diode array detection (DAD) methods were also used to help successfully identify and characterise the compounds being formed in these complex reactions. The overall results obtained in this paper allowed the optimal reaction conditions to be determined for this reaction. LC-MS analysis of the chromatographic peaks also identified the presence of two isomers of the diester substituted calix[4]arene (1,3 and 1,2 diesters). The combination of LC and UV/MS detection is required for accurate analysis of the products of such reactions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...