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1.
Age Ageing ; 52(9)2023 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-37742283

RESUMEN

BACKGROUND: The use of mobile health (mHealth) for asthma and chronic obstructive pulmonary disease (COPD) is rapidly growing and may help address the complex respiratory care needs of our ageing population. However, little is currently known about how airways mHealth is developed and used among older adults (≥65 years). OBJECTIVE: To identify if and how older adults with asthma and COPD have been incorporated across the mHealth research cycle. METHODS: We searched Ovid MEDLINE, EMBASE, CINAHL and the Cochrane Central Registry of Controlled Trials for studies pertaining to the development or evaluation of asthma and COPD mHealth for adults published after 2010. Study, participant and mHealth details, including any considerations of older age, were extracted, synthesised and charted. RESULTS: A total of 334 studies of 191 mHealth tools were identified. Adults ≥65 years old were included in 33.3% of asthma mHealth studies and 85.3% of COPD studies. Discussions of older age focused on barriers to technology use. Methodologic and/or analytic considerations of older age were mostly absent throughout the research cycle. Among the 28 instances quantitative age-related analyses were detailed, 12 described positive mHealth use and satisfaction outcomes in older adults versus negative or equivocal outcomes. CONCLUSION: We identified an overall lack of consideration for older age throughout the airways mHealth research cycle, even among COPD mHealth studies that predominantly included older adults. We also found a contrast between the perceptions of how older age might negatively influence mHealth use and available quantitative evaluations. Future airways mHealth research must better integrate the needs and concerns of older adults.


Asunto(s)
Asma , Enfermedad Pulmonar Obstructiva Crónica , Telemedicina , Humanos , Anciano , Asma/diagnóstico , Asma/terapia , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/terapia , Envejecimiento , Sistema de Registros
2.
J Med Internet Res ; 25: e45955, 2023 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-37606961

RESUMEN

BACKGROUND: The use of mobile health (mHealth) in asthma and chronic obstructive pulmonary disease (COPD) is growing, and as the population ages, a greater number of older adults stand to benefit from mHealth-enhanced airway disease care. Though older adults are a heterogeneous population of health technology users, older age represents a potential barrier to health technology adoption, and there is currently a lack of knowledge on how older age influences mHealth use in asthma and COPD. OBJECTIVE: In this qualitative study, we sought to explore the experiences and perspectives of adults who were aged 65 years and older with asthma and COPD toward mHealth use. METHODS: Semistructured individual interviews were conducted with adults who were aged 65 years and older with asthma or COPD and owned a smartphone. Applying phenomenological methodology, we analyzed interview transcripts in order to develop themes and propose an essential experience of mHealth use among older adults with airway disease. We then summarized our qualitative findings and proposed strategies to leverage our results in order to guide future research and implementation efforts targeting older adults' use of airway mHealth. RESULTS: Twenty participants (mean age 79.8, SD 4.4 years) were interviewed. Participants described a central tension between (1) the perception that mHealth could help maintain independence throughout aging and (2) an apprehension toward the ways in which mHealth could negatively affect established health care experiences. Several elements of these 2 themes are absent from previous research focusing on younger adults with asthma and COPD. The individual elements of these 2 themes informed potential strategies to optimize future older adults' use of asthma and COPD mHealth tools. CONCLUSIONS: Focusing on the perspectives and experiences of older adults with asthma and COPD in their use of mHealth identified novel understandings of health technology use in this important demographic in need of greater care. These lessons were translated into potential strategies that will need to be objectively evaluated in future airway mHealth research, development, and implementation efforts.


Asunto(s)
Asma , Enfermedad Pulmonar Obstructiva Crónica , Telemedicina , Humanos , Anciano , Asma/terapia , Enfermedad Pulmonar Obstructiva Crónica/terapia , Investigación Cualitativa , Envejecimiento
3.
BMC Med Inform Decis Mak ; 23(1): 226, 2023 10 18.
Artículo en Inglés | MEDLINE | ID: mdl-37853386

RESUMEN

BACKGROUND: Computerized clinical decision support systems (CDSSs) can improve care by bridging knowledge to practice gaps. However, the real-world uptake of such systems in health care settings has been suboptimal. We sought to: (1) use the Theoretical Domains Framework (TDF) to identify determinants (barriers/enablers) of uptake of the Electronic Asthma Management System (eAMS) CDSS; (2) match identified TDF belief statements to elements in the Guideline Implementation with Decision Support (GUIDES) Checklist; and (3) explore the relationship between the TDF and GUIDES frameworks and the usefulness of this sequential approach for identifying opportunities to improve CDSS uptake. METHODS: In Phase 1, we conducted semistructured interviews with primary care physicians in Toronto, Canada regarding the uptake of the eAMS CDSS. Using content analysis, two coders independently analyzed interview transcripts guided by the TDF to generate themes representing barriers and enablers to CDSS uptake. In Phase 2, the same reviewers independently mapped each belief statement to a GUIDES domain and factor. We calculated the proportion of TDF belief statements that linked to each GUIDES domain and the proportion of TDF domains that linked to GUIDES factors (and vice-versa) and domains. RESULTS: We interviewed 10 participants before data saturation. In Phase 1, we identified 53 belief statements covering 12 TDF domains; 18 (34.0%) were barriers, and 35 (66.0%) were enablers. In Phase 2, 41 statements (77.4%) linked to at least one GUIDES factor, while 12 (22.6%) did not link to any specific factor. The GUIDES Context Domain was linked to the largest number of belief statements (19/53; 35.8%). Each TDF domain linked to one or more GUIDES factor, with 6 TDF domains linking to more than 1 factor and 8 TDF domains linking to more than 1 GUIDES domain. CONCLUSIONS: The TDF provides unique insights into barriers and enablers to CDSS uptake, which can then be mapped to GUIDES domains and factors to identify required changes to CDSS context, content, and system. This can be followed by conventional mapping of TDF domains to behaviour change techniques to optimize CDSS implementation. This novel step-wise approach combines two established frameworks to optimize CDSS interventions, and requires prospective validation.


Asunto(s)
Lista de Verificación , Sistemas de Apoyo a Decisiones Clínicas , Humanos , Canadá , Investigación Cualitativa
4.
J Med Internet Res ; 22(10): e19474, 2020 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-33030437

RESUMEN

BACKGROUND: Electronic patient questionnaires are becoming ubiquitous in health care. To address care gaps that contribute to poor asthma management, we developed the Electronic Asthma Management System, which includes a previsit electronic patient questionnaire linked to a computerized clinical decision support system. OBJECTIVE: This study aims to identify the determinants (barriers and enablers) of patient uptake and completion of a previsit mobile health questionnaire. METHODS: We conducted semistructured interviews with adult patients with asthma in Toronto, Canada. After demonstrating the questionnaire, participants completed the questionnaire using their smartphones and were then interviewed regarding perceived barriers and enablers to using and completing the questionnaire. Interview questions were based on the Theoretical Domains Framework to identify the determinants of health-related behavior. We generated themes that addressed the enablers and barriers to the uptake and completion of the questionnaire. RESULTS: In total, 12 participants were interviewed for saturation. Key enablers were as follows: the questionnaire was easy to complete without additional knowledge or skills and was perceived as a priority and responsibility for patients, use could lead to more efficient and personalized care, completion on one's own time would be convenient, and uptake and completion could be optimized through patient reminders. Concerns about data security, the usefulness of questionnaire data, the stress of completing it accurately and on time, competing priorities, and preferences to complete the questionnaire on other devices were the main barriers. CONCLUSIONS: The barriers and enablers identified by patients should be addressed by developing implementation strategies to enhance e-questionnaire use and completion by patients. As the use of e-questionnaires grows, our findings will contribute to implementation efforts across settings and diseases.


Asunto(s)
Asma/epidemiología , Sistemas de Apoyo a Decisiones Clínicas/normas , Adulto , Electrónica , Femenino , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Investigación Cualitativa , Encuestas y Cuestionarios
5.
J Med Internet Res ; 22(9): e19358, 2020 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-32945779

RESUMEN

BACKGROUND: mHealth tablet-based interventions are increasingly being studied and deployed in various health care settings, yet little knowledge exists regarding patient uptake and acceptance or how patient demographics influence these important implementation metrics. OBJECTIVE: To determine which factors influence the uptake and successful completion of an mHealth tablet questionnaire by analyzing its implementation in a primary care setting. METHODS: We prospectively studied a patient-facing electronic touch-tablet asthma questionnaire deployed as part of the Electronic Asthma Management System. We describe tablet uptake and completion rates and corresponding predictor models for these behaviors. RESULTS: The tablet was offered to and accepted by patients in 891/1715 (52.0%) visits. Patients refused the tablet in 33.0% (439/1330) visits in which it was successfully offered. Patients aged older than 65 years of age (odds ratio [OR] 2.30, 95% CI 1.33-3.95) and with concurrent chronic obstructive pulmonary disease (OR 2.22, 95% CI 1.05-4.67) were more likely to refuse the tablet, and those on an asthma medication (OR 0.55, 95% CI 0.30-0.99) were less likely to refuse it. Once accepted, the questionnaire was completed in 784/891 (88.0%) instances, with those on an asthma medication (OR 0.53, 95% CI 0.32-0.88) being less likely to leave it incomplete. CONCLUSIONS: Older age predicted initial tablet refusal but not tablet questionnaire completion, suggesting that perceptions of mHealth among older adults may negatively impact uptake, independent of usability. The influence of being on an asthma medication suggests that disease severity may also mediate mHealth acceptance. Although use of mHealth questionnaires is growing rapidly across health care settings and diseases, few studies describe their real-world acceptance and its predictors. Our results should be complemented by qualitative methods to identify barriers and enablers to uptake and may inform technological and implementation strategies to drive successful usage.


Asunto(s)
Asma/diagnóstico , Asma/terapia , Atención Primaria de Salud/métodos , Telemedicina/métodos , Anciano , Femenino , Humanos , Masculino , Estudios Prospectivos , Encuestas y Cuestionarios
6.
Can Fam Physician ; 65(2): 103-106, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30765356

RESUMEN

OBJECTIVE: To improve the use of asthma action plans (AAPs) among primary care physicians. SOURCES OF INFORMATION: In a 2017 article, recent asthma guidelines and adult studies (January 2010 to March 2016) addressing acute loss of asthma control were reviewed to develop an evidence-based tool to help guide physicians in creating AAPs to maximize adherence and minimize errors. Evidence supporting the effects of AAPs is level I. Evidence supporting the recommendations in the tool ranges from level I to consensus. MAIN MESSAGE: A lack of knowledge about and training in creating appropriate AAP content is an important barrier to the use of AAPs, as is the fact that instructions provided by asthma guidelines are often difficult to integrate into real-world practice. In order to address these issues, a freely accessible, practical, evidence-based tool has recently been created, addressing both the knowledge and the practical barriers to AAP creation. This tool has been formatted as a printable bedside chart for the point of care, but could also be integrated into a computerized electronic decision support system in the future. CONCLUSION: Asthma action plans, in conjunction with asthma education and regular follow-up, can improve patients' symptoms and quality of life and reduce hospitalization. This novel point-of-care tool provides practical advice on how to complete AAPs to improve patients' asthma self-management.


Asunto(s)
Asma/terapia , Comunicación Interdisciplinaria , Grupo de Atención al Paciente/organización & administración , Médicos de Atención Primaria/organización & administración , Atención Primaria de Salud/organización & administración , Adulto , Instituciones de Atención Ambulatoria , Conducta Cooperativa , Medicina Basada en la Evidencia , Humanos , Mejoramiento de la Calidad/organización & administración , Autocuidado/métodos , Gestión de la Calidad Total/organización & administración
7.
Eur Respir J ; 49(5)2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28461295

RESUMEN

Asthma action plans (AAPs) reduce healthcare utilisation, improve quality of life and are recommended across guidelines. However, fewer than 25% of patients receive an AAP, partly due to prescribers' inability to complete "yellow zone" instructions (how to intensify therapy for acute loss of control). We sought to review best evidence to develop a practical, evidence-based tool to facilitate yellow zone guidance in adults.We reviewed recent asthma guidelines and adult studies addressing acute loss of asthma control (January 2010 to March 2016). We developed evidence-based rules for yellow zone therapy and operational guidelines to maximise adherence and minimise errors.We reviewed three guidelines and 11 manuscripts (2486 abstracts screened). Recommendations were comparable but some areas lacked guidance. For 15/43 asthma regimens, the commonly recommended four- to five-fold yellow zone inhaled corticosteroid dose increase was problematic due to regulatory dose limits. We identified evidence-based alternatives for 8/15 regimens. Operational guidance included increasing to a maximum of four inhalations while maintaining baseline inhaler frequency and device in the yellow zone.We developed a practical implementation tool to facilitate AAP delivery at the point of care, addressing existing gaps and uncertainties. Our tool should be implemented as part of a multifaceted approach to augment AAP usage.


Asunto(s)
Corticoesteroides/administración & dosificación , Antiasmáticos/administración & dosificación , Asma/tratamiento farmacológico , Sistemas de Atención de Punto , Antiasmáticos/uso terapéutico , Manejo de la Enfermedad , Medicina Basada en la Evidencia , Humanos , Nebulizadores y Vaporizadores , Guías de Práctica Clínica como Asunto , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto
8.
Can Fam Physician ; 65(7): 456-457, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31300423
9.
Can Fam Physician ; 65(2): e51-e55, 2019 02.
Artículo en Francés | MEDLINE | ID: mdl-30765369

RESUMEN

OBJECTIF: Améliorer l'utilisation des plans d'action pour l'asthme (PAA) par les omnipraticiens. SOURCES DE L'INFORMATION: Un article publié en 2017 passait en revue les récentes lignes directrices de prise en charge de l'asthme et les études menées auprès d'adultes (de janvier 2010 à mars 2016) portant sur la perte aiguë de la maîtrise de l'asthme, dans le but de créer un outil factuel pouvant orienter les médecins dans la création de PAA de manière à optimiser l'observance du traitement et à réduire les erreurs au minimum. Les données probantes étayant les effets des PAA sont de niveau I. Les données probantes étayant les recommandations faites dans l'outil varient entre le niveau I et le consensus. MESSAGE PRINCIPAL: Un obstacle important à l'emploi des PAA est l'absence de connaissances des PAA et de formation pour créer un contenu approprié, de même que la difficulté d'intégrer dans la pratique réelle les instructions fournies dans les lignes directrices sur l'asthme. Pour faire tomber ces obstacles, un outil factuel, pratique et facilement accessible a récemment vu le jour; il aborde les obstacles pratiques et liés aux connaissances en matière de création d'un PAA. Cet outil prend la forme d'un tableau à imprimer pouvant être utilisé au chevet du patient, mais il pourra aussi à l'avenir être intégré dans un système informatisé d'aide à la décision. CONCLUSION: Les plans d'action pour l'asthme, jumelés à l'éducation sur l'asthme et au suivi régulier, soulagent les symptômes, améliorent la qualité de vie et réduisent les hospitalisations. Ce nouvel outil de point de service fournit des conseils pratiques sur la façon de créer un PAA dans le but d'améliorer l'autoprise en charge de l'asthme.

11.
Implement Sci ; 17(1): 21, 2022 03 10.
Artículo en Inglés | MEDLINE | ID: mdl-35272667

RESUMEN

BACKGROUND: Computerized clinical decision support systems (CDSSs) are a promising knowledge translation tool, but often fail to meaningfully influence the outcomes they target. Low CDSS provider uptake is a potential contributor to this problem but has not been systematically studied. The objective of this systematic review and meta-regression was to determine reported CDSS uptake and identify which CDSS features may influence uptake. METHODS: Medline, Embase, CINAHL, and the Cochrane Database of Controlled Trials were searched from January 2000 to August 2020. Randomized, non-randomized, and quasi-experimental trials reporting CDSS uptake in any patient population or setting were included. The main outcome extracted was CDSS uptake, reported as a raw proportion, and representing the number of times the CDSS was used or accessed over the total number of times it could have been interacted with. We also extracted context, content, system, and implementation features that might influence uptake, for each CDSS. Overall weighted uptake was calculated using random-effects meta-analysis and determinants of uptake were investigated using multivariable meta-regression. RESULTS: Among 7995 citations screened, 55 studies involving 373,608 patients and 3607 providers met full inclusion criteria. Meta-analysis revealed that overall CDSS uptake was 34.2% (95% CI 23.2 to 47.1%). Uptake was only reported in 12.4% of studies that otherwise met inclusion criteria. Multivariable meta-regression revealed the following factors significantly associated with uptake: (1) formally evaluating the availability and quality of the patient data needed to inform CDSS advice; and (2) identifying and addressing other barriers to the behaviour change targeted by the CDSS. CONCLUSIONS AND RELEVANCE: System uptake was seldom reported in CDSS trials. When reported, uptake was low. This represents a major and potentially modifiable barrier to overall CDSS effectiveness. We found that features relating to CDSS context and implementation strategy best predicted uptake. Future studies should measure the impact of addressing these features as part of the CDSS implementation strategy. Uptake reporting must also become standard in future studies reporting CDSS intervention effects. REGISTRATION: Pre-registered on PROSPERO, CRD42018092337.


Asunto(s)
Sistemas de Apoyo a Decisiones Clínicas , Humanos
12.
Respir Med ; 201: 106568, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-34429221

RESUMEN

INTRODUCTION: In mild asthma, as-needed budesonide-formoterol offers similar protection from severe exacerbations as daily inhaled corticosteroids (ICS), with lower ICS exposure but slightly increased symptoms. We sought to develop an electronic decision aid to guide discussions about the pros and cons of these first-line options, while identifying and integrating user preferences. METHODS: Following International Patient Decision Aid Standards, we created a mild asthma decision aid prototype comparing convenience, clinical outcomes, cumulative ICS dose exposure, costs, and side-effects of each option. After face validation, the prototype was iteratively adapted through rapid-cycle development. Each cycle consisted of a patient focus group and a primary care physician interview. We made user preference-based improvements after each round, until reaching a pre-set stopping criterion (no new critical issues identified). We then performed a summative qualitative content analysis. RESULTS: Over 5 cycles, we recruited 21 asthma patients (12/21 women, 10/21 ≥ 60 years old) and 5 physicians. Serial changes included simplification and reduction of text and reading level, inclusion of an ICS "myths" section and elaboration of patient-friendly infographics for numerical comparisons. User preferences fell within Content, Format, and tool use Process themes. In response to decision-making preferences, we created a complementary one-page conversation aid for patient-provider use at the point-of-care. CONCLUSIONS: We present preference-based electronic patient decision and conversation aids for treatment of mild asthma. Our user preference analyses offer useful insights for development of such tools in other chronic diseases. These tools now require integration into point-of-care workflows for measurement of real-world uptake and impact.


Asunto(s)
Antiasmáticos , Asma , Corticoesteroides/uso terapéutico , Asma/tratamiento farmacológico , Combinación Budesonida y Fumarato de Formoterol/uso terapéutico , Técnicas de Apoyo para la Decisión , Femenino , Humanos , Persona de Mediana Edad
13.
Eur Respir Rev ; 30(162)2021 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-34615699

RESUMEN

175 years have elapsed since John Hutchinson introduced the world to his version of an apparatus that had been in development for nearly two centuries, the spirometer. Though he was not the first to build a device that sought to measure breathing and quantify the impact of disease and occupation on lung function, Hutchison coined the terms spirometer and vital capacity that are still in use today, securing his place in medical history. As Hutchinson envisioned, spirometry would become crucial to our growing knowledge of respiratory pathophysiology, from Tiffeneau and Pinelli's work on forced expiratory volumes, to Fry and Hyatt's description of the flow-volume curve. In the 20th century, standardization of spirometry further broadened its reach and prognostic potential. Today, spirometry is recognized as essential to respiratory disease diagnosis, management and research. However, controversy exists in some of its applications, uptake in primary care remains sub-optimal and there are concerns related to the way in which race is factored into interpretation. Moving forward, these failings must be addressed, and innovations like Internet-enabled portable spirometers may present novel opportunities. We must also consider the physiologic and practical limitations inherent to spirometry and further investigate complementary technologies such as respiratory oscillometry and other emerging technologies that assess lung function. Through an exploration of the storied history of spirometry, we can better contextualize its current landscape and appreciate the trends that have repeatedly arisen over time. This may help to improve our current use of spirometry and may allow us to anticipate the obstacles confronting emerging pulmonary function technologies.


Asunto(s)
Pulmón , Trastornos Respiratorios , Volumen Espiratorio Forzado , Humanos , Espirometría , Capacidad Vital
14.
Chest ; 158(6): 2502-2510, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32652095

RESUMEN

To reduce the spread of the severe acute respiratory syndrome coronavirus 2, many pulmonary function testing (PFT) laboratories have been closed or have significantly reduced their testing capacity. Because these mitigation strategies may be necessary for the next 6 to 18 months to prevent recurrent peaks in disease prevalence, fewer objective measurements of lung function will alter the diagnosis and care of patients with chronic respiratory diseases. PFT, which includes spirometry, lung volume, and diffusion capacity measurement, is essential to the diagnosis and management of patients with asthma, COPD, and other chronic lung conditions. Both traditional and innovative alternatives to conventional testing must now be explored. These may include peak expiratory flow devices, electronic portable spirometers, portable exhaled nitric oxide measurement, airwave oscillometry devices, and novel digital health tools such as smartphone microphone spirometers and mobile health technologies along with integration of machine learning approaches. The adoption of some novel approaches may not merely replace but could improve existing management strategies and alter common diagnostic paradigms. With these options comes important technical, privacy, ethical, financial, and medicolegal barriers that must be addressed. However, the coronavirus disease 19 pandemic also presents a unique opportunity to augment conventional testing by including innovative and emerging approaches to measuring lung function remotely in patients with respiratory disease. The benefits of such an approach have the potential to enhance respiratory care and empower patient self-management well beyond the current global pandemic.


Asunto(s)
COVID-19 , Atención a la Salud/métodos , Enfermedades Pulmonares/diagnóstico , Enfermedades Pulmonares/terapia , Pruebas de Función Respiratoria/instrumentación , Pruebas de Función Respiratoria/métodos , Asma/diagnóstico , Asma/fisiopatología , Asma/terapia , Pruebas Respiratorias/instrumentación , Pruebas Respiratorias/métodos , Enfermedad Crónica , Fibrosis Quística/diagnóstico , Fibrosis Quística/terapia , Humanos , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/terapia , Invenciones , Enfermedades Pulmonares/fisiopatología , Enfermedades Pulmonares Intersticiales/diagnóstico , Enfermedades Pulmonares Intersticiales/terapia , Mediciones del Volumen Pulmonar , Aprendizaje Automático , Oscilometría/instrumentación , Oscilometría/métodos , Ápice del Flujo Espiratorio , Capacidad de Difusión Pulmonar/instrumentación , Capacidad de Difusión Pulmonar/métodos , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/terapia , Automanejo , Teléfono Inteligente , Espirometría/instrumentación , Espirometría/métodos
15.
Mol Cancer Ther ; 6(8): 2280-9, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17671082

RESUMEN

Prolonged, frequently administered low-dose metronomic chemotherapy (LDM) is being explored (pre)clinically as a promising antiangiogenic antitumor strategy. Although appealing because of a favorable side effect profile and mostly oral dosing, LDM involves new challenges different from conventional maximum tolerated dose chemotherapy. These include possible altered pharmacokinetic characteristics due to long-term drug exposure potentially resulting in acquired resistance and increased risk of unfavorable drug interactions. We therefore compared the antitumor and antivascular effects of LDM cyclophosphamide (CPA) given to mice that had been pretreated with either LDM CPA or normal saline, obtained blood 4-hydroxy-CPA (activated CPA) concentrations using either gas chromatography/mass spectrometry or liquid chromatography/tandem mass spectrometry in mice treated with LDM CPA, and measured hepatic and intratumoral activity of enzymes involved in the biotransformation of CPA and many other drugs [i.e., cytochrome P450 3A4 (CYP3A4) and aldehyde dehydrogenase]. Exposure of mice to LDM CPA for >or=8 weeks did not compromise subsequent activity of LDM CPA therapy, and biologically active 4-hydroxy-CPA levels were maintained during long-term LDM CPA administration. Whereas the effects on CYP3A4 were complex, aldehyde dehydrogenase activity was not affected. In summary, our findings suggest that acquired resistance to LDM CPA is unlikely accounted for by altered CPA biotransformation. In the absence of reliable pharmacodynamic surrogate markers, pharmacokinetic parameters might become helpful to individualize/optimize LDM CPA therapy. LDM CPA-associated changes of CYP3A4 activity point to a potential risk of unfavorable drug interactions when compounds that are metabolized by CYP3A4 are coadministered with LDM CPA.


Asunto(s)
Antineoplásicos Alquilantes/administración & dosificación , Antineoplásicos Alquilantes/farmacocinética , Ciclofosfamida/administración & dosificación , Ciclofosfamida/farmacocinética , Aldehído Deshidrogenasa/metabolismo , Animales , Antineoplásicos Alquilantes/química , Antineoplásicos Alquilantes/farmacología , Biotransformación , Línea Celular Tumoral , Colágeno/metabolismo , Ciclofosfamida/química , Ciclofosfamida/farmacología , Sistema Enzimático del Citocromo P-450/metabolismo , Esquema de Medicación , Combinación de Medicamentos , Femenino , Humanos , Laminina/metabolismo , Hígado/efectos de los fármacos , Hígado/enzimología , Masculino , Ratones , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Neovascularización Patológica , Proteoglicanos/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
16.
Neoplasia ; 13(1): 40-8, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21245939

RESUMEN

Low-dose metronomic (LDM) chemotherapy is emerging as an alternative or supplemental dosing strategy to conventional maximum tolerated dose (MTD) chemotherapy. It is characterized primarily, but not exclusively, by antiangiogenic mechanisms of action and the absence of high-grade adverse effects commonly seen with MTD chemotherapy. However, similar to other anticancer therapies, inherent resistance to LDM chemotherapy is common. Moreover, even tumors that initially respond to metronomic regimens eventually develop resistance through mechanisms that are as yet unknown. Thus, we have developed in vivo models of PC-3 human prostate cancer cells resistant to extended LDM cyclophosphamide therapy. Such PC-3 variants show stable resistance to LDM cyclophosphamide in vivo yet retain in vitro sensitivity to 4-hydroperoxy-cyclophosphamide (precursor of the active cyclophosphamide metabolite 4-hydroxy-cyclophosphamide) and other chemotherapeutic agents, namely, docetaxel and doxorubicin. Moreover, LDM cyclophosphamide-resistant PC-3 variants remain sensitive to MTD cyclophosphamide therapy in vivo. Conversely, PC-3 variants made resistant in vivo to MTD cyclophosphamide show varying levels of resistance to metronomic cyclophosphamide when grown in mice. These results and additional studies of variants of the breast cancer cell line MDA-MB-231 suggest that resistance to LDM cyclophosphamide is a distinct phenomenon from resistance to MTD cyclophosphamide and that LDM cyclophosphamide administration does not select for MTD chemotherapy resistance. As such, our findings have various implications for the clinical use of metronomic chemotherapy.


Asunto(s)
Ciclofosfamida/administración & dosificación , Animales , Proliferación Celular/efectos de los fármacos , Resistencia a Antineoplásicos , Humanos , Masculino , Dosis Máxima Tolerada , Ratones , Trasplante de Neoplasias , Carga Tumoral/efectos de los fármacos , Células Tumorales Cultivadas
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