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1.
Crit Rev Biomed Eng ; 47(3): 235-247, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31679258

RESUMEN

Fertility hormone levels are constantly changing, but it is crucial for a woman to be able to monitor her fertility levels if she is interested in conceiving. Women and physicians often have a difficult time determining ovulation windows due to fluctuating menstrual cycles and inaccurate interpretations of hormone levels. Current methods of fertility monitoring include physical or vaginal exams, laparoscopy, ultrasound scans, as well as evaluation of hormone levels. A rapid, at-home fertility monitoring tool can help alleviate the apprehensiveness associated with routine screenings and give women the privacy desired when trying to conceive. Herein, we discuss the development of an electrochemical biosensor for quantification of three fertility hormones: beta-estradiol, progesterone, and FSH. Each biomarker's MRE was immobilized onto a gold disk electrode through the use of self-assembled monolayer linking chemistry. Using electrochemical impedance spectroscopy (EIS), the biomarker concentration was correlated to impedance magnitude. An optimal binding frequency was identified for each biomarker, permitting simplistic hardware requirements and investigation into multimarker detection. Analytes were tested in both purified solutions and 1%-90% whole blood. Each biomarker exhibited a unique imaginary impedance peak and optimal binding frequency. The determination was made by assessing the response parameters including the linear fit correlation across the physiological hormone ranges. The existence of unique optimal frequencies permits for simultaneous detection of multiple hormones in a single test. Additionally, the identified frequency was robust across purified and complex solutions. Response characteristics were negatively impacted by the introduction of blood-based contaminants. However, the introduction of Nafion membranes, similar to ones used in commercial glucose sensors, is both feasible and beneficial.


Asunto(s)
Técnicas Biosensibles/métodos , Espectroscopía Dieléctrica , Electroquímica/métodos , Estradiol/sangre , Hormona Folículo Estimulante/sangre , Progesterona/sangre , Animales , Biomarcadores/sangre , Calibración , Femenino , Fertilidad , Oro , Hormona Luteinizante/sangre , Conejos , Propiedades de Superficie
2.
J Diabetes Sci Technol ; 8(1): 109-116, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24876546

RESUMEN

OBJECTIVE: A prototype tear glucose (TG) sensor was tested in New Zealand white rabbits to assess eye irritation, blood glucose (BG) and TG lag time, and correlation with BG. METHODS: A total of 4 animals were used. Eye irritation was monitored by Lissamine green dye and analyzed using image analysis software. Lag time was correlated with an oral glucose load while recording TG and BG readings. Correlation between TG and BG were plotted against one another to form a correlation diagram, using a Yellow Springs Instrument (YSI) and self-monitoring of blood glucose as the reference measurements. Finally, TG levels were calculated using analytically derived expressions. RESULTS: From repeated testing carried over the course of 12 months, little to no eye irritation was detected. TG fluctuations over time visually appeared to trace the same pattern as BG with an average lag times of 13 minutes. TG levels calculated from the device current measurements ranged from 4 to 20 mg/dL and correlated linearly with BG levels of 75-160 mg/dL (TG = 0.1723 BG = 7.9448 mg/dL; R2 = .7544). CONCLUSION: The first steps were taken toward preliminary development of a sensor for self-monitoring of tear glucose (SMTG). No conjunctival irritation in any of the animals was noted. Lag time between TG and BG was found to be noticeable, but a quantitative modeling to correlate lag time in this study is unnecessary. Measured currents from the sensors and the calculated TG showed promising correlation to BG levels. Previous analytical bench marking showed BG and TG levels consistent with other literature.

3.
Anal Chim Acta ; 738: 27-34, 2012 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-22790696

RESUMEN

Two ordered, soft-templated mesoporous carbon powders with cubic and hexagonal framework structure and four different commercial, low cost methacrylate-based polymer binders with widely varying physical properties are investigated as screen printed electrodes for glucose sensors using glucose oxidase and ferricyanide as the mediator. Both the chemistry and concentration of the binder in the electrode formulation can significantly impact the performance. Poly(hydroxybutyl methacrylate) as the binder provides hydrophilicity to enable transport of species in the aqueous phase to the carbon surface, but yet is sufficiently hydrophobic to provide mechanical robustness to the sensor. The current from the mesoporous carbon electrodes can be more than an order of magnitude greater than for a commercial printed carbon electrode (Zensor) with improved sensitivity for model glucose solutions. Even when applying these sensors to rabbit whole blood, the performance of these glucose sensors compares favorably to a standard commercial glucose meter with the lower detection limit of the mesoporous electrode being approximately 20mgdL(-1) despite the lack of a separation membrane to prevent non-specific events; these results suggest that the small pore sizes and high surface areas associated with ordered mesoporous carbons may effectively decrease some non-specific inferences for electrochemical sensing.


Asunto(s)
Técnicas Biosensibles/instrumentación , Glucemia/análisis , Carbono/química , Técnicas Electroquímicas/instrumentación , Ácidos Polimetacrílicos/química , Animales , Técnicas Biosensibles/métodos , Diabetes Mellitus/sangre , Electrodos , Ferricianuros/química , Formaldehído/química , Glucosa Oxidasa/química , Humanos , Límite de Detección , Microscopía Electrónica de Transmisión , Fenoles/química , Poloxámero/química , Polímeros/química , Conejos
4.
N Engl J Med ; 356(18): 1853-61, 2007 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-17476011

RESUMEN

BACKGROUND: In 1992, Medicare implemented the resource-based relative-value scale, which established payments for physicians' services based on relative costs. We conducted a study to determine how the use of physicians' services changed during the first decade after the implementation of this scale. METHODS: With the resource-based relative-value scale, Medicare payments are based on the number of relative-value units (RVUs) assigned to physicians' services. The total number of RVUs reflects the volume of physicians' work (the time, skill, and training required for a physician to provide the service), practice expenses, and professional-liability insurance. Using national data from Medicare on physicians' services and American Medical Association files on RVUs, we analyzed the growth in RVUs per Medicare beneficiary from 1992 to 2002 according to the type of service and specialty. We also examined this growth with respect to the quantity and mix of services, revisions in the valuation of RVUs, and new service codes. RESULTS: Between 1992 and 2002, the volume of physicians' work per Medicare beneficiary grew by 50%, and the total RVUs per Medicare beneficiary grew by 45%. The quantity and mix of services were the largest sources of growth, increasing by 19% for RVUs for physicians' work and by 22% for total RVUs. Our findings varied among services and specialties. Revised valuation of RVUs was a key source of the growth in RVUs for physicians' work and total RVUs for evaluation and management and for tests. New service codes were the largest drivers of growth for major procedures (accounting for 36% of the growth in RVUs for physicians' work and 35% of the growth in total RVUs), and the quantity and mix of existing services were the largest drivers of growth for imaging. The growth in RVUs for physicians' work was greatest in cardiology (114%) and gastroenterology (72%). The total growth in RVUs was greatest in cardiology (99%) and dermatology (105%). CONCLUSIONS: In the first 10 years after the implementation of the resource-based relative-value scale, RVUs per Medicare beneficiary grew substantially. The leading sources of growth varied among service types and specialties. An understanding of these sources of growth can inform policies to control Medicare spending.


Asunto(s)
Servicios de Salud/estadística & datos numéricos , Medicare/tendencias , Médicos/estadística & datos numéricos , Escalas de Valor Relativo , Tabla de Aranceles/tendencias , Gastos en Salud/tendencias , Servicios de Salud/tendencias , Humanos , Revisión de Utilización de Seguros , Medicare/economía , Medicare/estadística & datos numéricos , Médicos/tendencias , Estados Unidos , Carga de Trabajo/estadística & datos numéricos
5.
J Surg Oncol ; 95(5): 370-85, 2007 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-17372933

RESUMEN

Four policy challenges that face the rehabilitation community in providing services to surgical cancer patients are reviewed: (1) achieving capacity to meet the complex rehabilitation needs of a growing population of cancer patients and long-term survivors; (2) identifying effective models for delivering cancer rehabilitation services; (3) understanding complex insurance coverage and payment policies and determining their effects on access to rehabilitation services; and (4) investing in clinical and health services research to guide rehabilitation practice. Recommendations are made to increase the recognition of cancer rehabilitation as an essential component of cancer survivors' care, improve access to appropriate rehabilitation services, and accelerate the pace of cancer rehabilitation research.


Asunto(s)
Instituciones de Atención Ambulatoria , Atención a la Salud , Política de Salud , Seguro de Salud , Neoplasias/rehabilitación , Procedimientos Quirúrgicos Operativos/rehabilitación , Atención Ambulatoria , Atención a la Salud/economía , Costos de la Atención en Salud , Política de Salud/legislación & jurisprudencia , Investigación sobre Servicios de Salud , Humanos , Medicare , Neoplasias/economía , Neoplasias/cirugía , Enfermería en Rehabilitación
6.
Health Care Financ Rev ; 29(2): 65-79, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-18435224

RESUMEN

In 1999, Medicare implemented a resource-based relative value unit (RVU) system for physician practice expense payments, and increased the number of services for which practice expense payments differ by site. Using 1998-2004 data, we examined RVU growth and decomposed that growth into resource-based RVUs, site of service, and service quantity and mix. We found that the number services with site of service differentials doubled, and that shifts in site of service and introduction of resource-based practice expenses (RBPE)were important sources of change in practice expense RVU volume. Service quantity and mix remained the largest source of growth in total RVU volume.


Asunto(s)
Servicios de Salud/provisión & distribución , Medicare , Administración de la Práctica Médica/economía , Algoritmos , Administración de la Práctica Médica/organización & administración , Escalas de Valor Relativo , Estados Unidos
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