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1.
J R Soc Interface ; 19(187): 20210642, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35104431

RESUMEN

Bone has a sophisticated architecture characterized by a hierarchical organization, starting at the sub-micrometre level. Thus, the analysis of the mechanical and structural properties of bone at this scale is essential to understand the relationship between its physiology, physical properties and chemical composition. Here, we unveil the potential of Brillouin-Raman microspectroscopy (BRaMS), an emerging correlative optical approach that can simultaneously assess bone mechanics and chemistry with micrometric resolution. Correlative hyperspectral imaging, performed on a human diaphyseal ring, reveals a complex microarchitecture that is reflected in extremely rich and informative spectra. An innovative method for mechanical properties analysis is proposed, mapping the intermixing of soft and hard tissue areas and revealing the coexistence of regions involved in remodelling processes, nutrient transportation and structural support. The mineralized regions appear elastically inhomogeneous, resembling the pattern of the osteons' lamellae, while Raman and energy-dispersive X-ray images through scanning electron microscopy show an overall uniform distribution of the mineral content, suggesting that other structural factors are responsible for lamellar micromechanical heterogeneity. These results, besides giving an important insight into cortical bone tissue properties, highlight the potential of BRaMS to access the origin of anisotropic mechanical properties, which are almost ubiquitous in other biological tissues.


Asunto(s)
Huesos , Osteón , Anisotropía , Huesos/diagnóstico por imagen , Hueso Cortical , Osteón/fisiología , Humanos , Microscopía Electrónica de Rastreo , Espectrometría Raman/métodos
2.
Nanotechnology ; 28(50): 505710, 2017 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-29064371

RESUMEN

We studied the emission of bare and aluminum quinoline (Alq3)/gold coated wurtzite GaN nanorods by temperature- and intensity-dependent time-integrated and time-resolved photoluminescence (PL). The GaN nanorods of ∼1.5 µm length and ∼250 nm diameter were grown by plasma-assisted molecular beam epitaxy. Gold/Alq3 coated GaN nanorods were synthesized by organic molecular beam deposition. The near band-edge and donor-acceptor pair luminescence was investigated in bare GaN nanorods and compared with multilevel model calculations providing the dynamical parameters for electron-hole pairs, excitons, impurity bound excitons, donors and acceptors. Subsequently, the influence of a 10 nm gold coating without and with an Alq3 spacer layer was studied and the experimental results were analyzed with the multilevel model. Without a spacer layer, a significant PL quenching and lifetime reduction of the near band-edge emission is found. The behavior is attributed to surface band-bending and Förster energy transfer from excitons to surface plasmons in the gold layer. Inserting a 5 nm Alq3 spacer layer reduces the PL quenching and lifetime reduction which is consistent with a reduced band-bending and Förster energy transfer. Increasing the spacer layer to 30 nm results in lifetimes which are similar to uncoated structures, showing a significantly decreased influence of the gold coating on the excitonic dynamics.

3.
Respir Physiol Neurobiol ; 240: 17-25, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-28213202

RESUMEN

Experiments were undertaken to mechanistically define expiratory-muscle contribution to effectiveness of cough while controlling glottic movement. We hypothesized that electrical abdominal-muscle stimulation in patients with respiratory-muscle weakness produces effective coughs only when glottic closure accompanies coughs. In ten spinal-cord-injury patients, esophago-gastric pressure and airflow were recorded during solicited-coughs, coughs augmented by abdominal-muscle stimulation, and passive open-glottis exhalations. During solicited-coughs, patients closed the glottis initially; five were flow-limited, five non-flow-limited. Stimulations during solicited-coughs or open-glottis exhalations elicited similar driving pressures (changes in gastric pressure; p<0.001). Despite high driving pressures, stimulations induced flow-limitation only when patients transiently closed the glottis - not during open-glottis exhalations. That is, transient glottic closure enabled transmission of abdominal (driving) pressure to the thorax during cough, while impeding dissipation of intrathoracic pressure. In conclusion, transient glottic closure is necessary to render cough effective in patients with respiratory-muscle weakness, indicating that failure to close the glottis contributes to ineffective cough in weak tracheostomized patients and patients with bulbar disorders.


Asunto(s)
Tos/diagnóstico , Tos/etiología , Debilidad Muscular/complicaciones , Debilidad Muscular/patología , Músculos Respiratorios/fisiopatología , Músculos Abdominales/fisiopatología , Adulto , Anciano , Análisis de Varianza , Estimulación Eléctrica/métodos , Electromiografía , Espiración , Femenino , Glotis/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Debilidad Muscular/etiología , Traumatismos de la Médula Espinal/complicaciones , Capacidad Pulmonar Total/fisiología
4.
Phys Rev Lett ; 116(23): 237401, 2016 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-27341256

RESUMEN

We present a first-order perturbation theory to calculate the frequency shift and linewidth change of photonic resonances in one- and two-dimensional periodic structures under modifications of the surrounding refractive index. Our method is based on the resonant state expansion, for which we extend the analytical mode normalization to periodic structures. We apply this theory to calculate the sensitivity of bright dipolar and much darker quadrupolar plasmonic modes by determining the maximum shift and optimal sensing volume.

5.
Phys Rev Lett ; 115(8): 089402, 2015 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-26340220
6.
Phys Rev Lett ; 113(10): 103901, 2014 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-25238359

RESUMEN

We investigate the propagation and scattering of polaritons in a planar GaAs microcavity in the linear regime under resonant excitation. The propagation of the coherent polariton wave across an extended defect creates phase and intensity patterns with identical qualitative features previously attributed to dark and half-dark solitons of polaritons. We demonstrate that these features are observed for negligible nonlinearity (i.e., polariton-polariton interaction) and are, therefore, not sufficient to identify dark and half-dark solitons. A linear model based on the Maxwell equations is shown to reproduce the experimental observations.

7.
Biophys J ; 105(6): 1414-20, 2013 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-24047993

RESUMEN

Giant unilamellar vesicles are a widely utilized model membrane system, providing free-standing bilayers unaffected by support-induced artifacts. To measure the lamellarity of such vesicles, fluorescence microscopy is one commonly utilized technique, but it has the inherent disadvantages of requiring lipid staining, thereby affecting the intrinsic physical and chemical properties of the vesicles, and it requires a calibration by statistical analysis of a vesicle ensemble. Herein we present what we believe to be a novel label-free optical method to determine the lamellarity of giant vesicles based on quantitative differential interference contrast (qDIC) microscopy. The method is validated by comparison with fluorescence microscopy on a statistically significant number of vesicles, showing correlated quantization of the lamellarity. Importantly, qDIC requires neither sample-dependent calibration nor sample staining, and thus can measure the lamellarity of any giant vesicle without additional preparation or interference with subsequent investigations. Furthermore, qDIC requires only a microscope equipped with differential interference contrast and a digital camera.


Asunto(s)
Microscopía de Contraste de Fase , Liposomas Unilamelares/química , Espectrometría de Fluorescencia
8.
Nat Commun ; 4: 1747, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23612288

RESUMEN

Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. This process is intuitively pictured by a pair of mechanical oscillators, coupled by a spring, allowing for a reversible exchange of excitation. On a microscopic level, the most relevant mechanism of coherent coupling of distant quantum bits--like trapped ions, superconducting qubits or excitons confined in semiconductor quantum dots--is coupling via the electromagnetic field. Here we demonstrate the controlled coherent coupling of spatially separated quantum dots via the photon mode of a solid state microresonator using the strong exciton-photon coupling regime. This is enabled by two-dimensional spectroscopy of the sample's coherent response, a sensitive probe of the coherent coupling. The results are quantitatively understood in a rigorous description of the cavity-mediated coupling of the quantum dot excitons. This mechanism can be used, for instance in photonic crystal cavity networks, to enable a long-range, non-local coherent coupling.

9.
Respir Med ; 105(3): 494-505, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20851591

RESUMEN

Helium-oxygen mixtures and pressure-support ventilation have been used to unload the respiratory muscles and increase exercise tolerance in COPD. Considering the different characteristics of these techniques, we hypothesized that helium-oxygen would be more effective in reducing exercise-induced dynamic hyperinflation than pressure-support. We also hypothesized that patients would experience greater increases in respiratory rate and minute ventilation with helium-oxygen than with pressure-support. The hypotheses were tested in ten patients with severe COPD (FEV(1) = 28 ± 3% predicted [mean ± SE]) during constant-load cycling (80% maximal workrate) while breathing 30% oxygen-alone, helium-oxygen, and pressure-support in randomized order. As hypothesized, helium-oxygen had greater impact on dynamic hyperinflation than did pressure-support (end-exercise; p = 0.03). For the most part of exercise, respiratory rate and minute ventilation were greater with helium-oxygen than with pressure-support (p ≤ 0.008). During the initial phases of exercise, helium-oxygen caused less rib-cage muscle recruitment than did pressure-support (p < 0.03), and after the start of exercise it caused greater reduction in inspiratory reserve volume (p ≤ 0.02). Despite these different responses, helium-oxygen and pressure-support caused similar increases in exercise duration (oxygen-alone: 6.9 ± 0.8 min; helium-oxygen: 10.7 ± 1.4 min; pressure-support: 11.2 ± 1.6 min; p = 0.003) and similar decreases in inspiratory effort (esophageal pressure-time product), respiratory drive, pulmonary resistance, dyspnea and leg effort (p < 0.03). In conclusion, helium-oxygen reduced exercise-induced dynamic hyperinflation by improving the relationship between hyperinflation and minute ventilation. In contrast, pressure-support reduced hyperinflation solely as a result of lowering ventilation. Helium-oxygen was more effective in reducing exercise-induced dynamic hyperinflation in severe COPD, and was associated with greater increases in respiratory rate and minute ventilation than pressure-support.


Asunto(s)
Terapia por Ejercicio/métodos , Tolerancia al Ejercicio/fisiología , Helio/administración & dosificación , Oxígeno/administración & dosificación , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Análisis de Varianza , Tolerancia al Ejercicio/efectos de los fármacos , Femenino , Helio/farmacología , Humanos , Mediciones del Volumen Pulmonar , Masculino , Persona de Mediana Edad , Oxígeno/farmacología , Terapia por Inhalación de Oxígeno/métodos , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación
10.
Nat Mater ; 9(4): 304-8, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20208523

RESUMEN

In spite of their different natures, light and matter can be unified under the strong-coupling regime, yielding superpositions of the two, referred to as dressed states or polaritons. After initially being demonstrated in bulk semiconductors and atomic systems, strong-coupling phenomena have been recently realized in solid-state optical microcavities. Strong coupling is an essential ingredient in the physics spanning from many-body quantum coherence phenomena, such as Bose-Einstein condensation and superfluidity, to cavity quantum electrodynamics. Within cavity quantum electrodynamics, the Jaynes-Cummings model describes the interaction of a single fermionic two-level system with a single bosonic photon mode. For a photon number larger than one, known as quantum strong coupling, a significant anharmonicity is predicted for the ladder-like spectrum of dressed states. For optical transitions in semiconductor nanostructures, first signatures of the quantum strong coupling were recently reported. Here we use advanced coherent nonlinear spectroscopy to explore a strongly coupled exciton-cavity system. We measure and simulate its four-wave mixing response, granting direct access to the coherent dynamics of the first and second rungs of the Jaynes-Cummings ladder. The agreement of the rich experimental evidence with the predictions of the Jaynes-Cummings model is proof of the quantum strong-coupling regime in the investigated solid-state system.

11.
Med Sci Sports Exerc ; 42(4): 691-700, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19952846

RESUMEN

INTRODUCTION: The objectives of this descriptive study were (a) to determine the energy expenditure of activities commonly performed by individuals with a spinal cord injury (SCI) and summarize this information and (b) to measure resting energy expenditure and establish the value of 1 MET for individuals with SCI. METHODS: One-hundred seventy adults with SCI were partitioned by gender, anatomical level of SCI, and American Spinal Injury Association designations for motor function. Twenty-seven physical activities, 12 recreational/sport and 15 daily living, were performed, while energy expenditure was measured continuously via a COSMED K4b portable metabolic system. In addition, 66 adult males with SCI completed 30 min of supine resting energy testing in a quiet environment. RESULTS: Results for the 27 measured activities are reported in kilocalories per minute (kcal·min(-1)) and VO2 (mL·min(-1) and mL·kg(-1)·min(-1)). One MET for a person with SCI should be adjusted using 2.7 mL·kg(-1)·min(-1). Using 2.7 mL·kg(-1)·min(-1), the MET range for persons in the motor incomplete SCI group was 1.17 (supported standing) to 6.22 (wheeling on grass), and 2.26 (billiards) to 16.25 (hand cycling) for activities of daily living and fitness/recreation, respectively. The MET range for activities of daily living for persons in the group with motor complete SCI was 1.27 (dusting) to 4.96 (wheeling on grass) and 1.47 (bait casting) to 7.74 (basketball game) for fitness/recreation. CONCLUSIONS: The foundation for a compendium of energy expenditure for physical activities for persons with SCI has been created with the completion of this study. In the future, others will update and expand the content of this compendium as has been the case with the original compendium for the able-bodied.


Asunto(s)
Metabolismo Energético/fisiología , Actividad Motora/fisiología , Traumatismos de la Médula Espinal/metabolismo , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obesidad , Consumo de Oxígeno , Valores de Referencia , Traumatismos de la Médula Espinal/fisiopatología , Silla de Ruedas
12.
Am J Respir Crit Care Med ; 177(8): 844-52, 2008 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-18202351

RESUMEN

RATIONALE: Exercise-induced dynamic hyperinflation contributes to decreased exercise tolerance in chronic obstructive pulmonary disease (COPD). It is unknown whether respiratory retraining (ventilation-feedback [VF] training) can affect exercise-induced dynamic hyperinflation and increase exercise tolerance. OBJECTIVES: To determine whether patients with COPD would achieve longer exercise duration if randomized to a combination of exercise training plus VF training than either form of training on its own. METHODS: A total of 64 patients randomized to 1 of 3 groups: VF plus exercise (n = 22), exercise alone (n = 20), and VF alone (n = 22). MEASUREMENTS AND MAIN RESULTS: Exercise duration before and after 36 training sessions and exercise-induced dynamic hyperinflation and respiratory pattern before and after training were measured. In the 49 patients who completed training, duration of constant work-rate exercise was 40.0 (+/- 20.4) minutes (mean +/- SD) with VF plus exercise, 31.5 (+/- 17.3) minutes with exercise alone, and 16.1 (+/- 19.3) minutes with VF alone. Exercise duration was longer in VF plus exercise than in VF alone (P < 0.0001), but did not reach predetermined statistical significance when VF plus exercise was compared with exercise alone (P = 0.022) (because of multiple comparisons, P

Asunto(s)
Biorretroalimentación Psicológica/métodos , Ejercicios Respiratorios , Terapia por Ejercicio/métodos , Tolerancia al Ejercicio/fisiología , Enfermedad Pulmonar Obstructiva Crónica/rehabilitación , Terapia Respiratoria/métodos , Anciano , Ciclismo , Prueba de Esfuerzo , Hospitales de Veteranos , Humanos , Persona de Mediana Edad , Caminata
13.
Artículo en Inglés | MEDLINE | ID: mdl-17375878

RESUMEN

OBJECTIVE: The objective of this study was to demonstrate improvement in nerve function with moderate exercise in patients with type II diabetic neuropathies. RESEARCH DESIGN AND METHODS: Fives subjects with type II diabetes mellitus and distal, predominantly sensory polyneuropathies were studied. The subjects completed an 8-week program of a supervised moderate exercise program (40-75% of maximal 02 uptake reserve) with a subsequent 16-week program of monitored similar exercise. The same experienced electrophysiologist performed the electrodiagnostic studies both before and after the 24-week exercise period. These studies monitored physiological changes (conduction velocities, response amplitudes) in motor and sensory fibers as well as F-wave latencies. RESULTS: The exercise program produced a documented increase in aerobic exercise capacity. Despite the small number of subjects studied and the relatively short exercise period, there was a statistically significant improvement in nearly all electrophysiological parameters evaluated post exercise including motor conduction velocities and amplitudes, sensory conduction velocities, and F-wave latencies. This improvement included a statistically significant improvement in absolute median motor evoked response amplitudes as well as the recording of sensory nerve action potentials not present prior to exercise. There were no adverse effects from the exercise. CONCLUSIONS: This study supports the hypothesis that exercise can be performed safely in patients with type II diabetic neuropathies and can produce improvement in their nerve function. This study also supports the hypothesis that ischemia may have a meaningful role in the pathogenesis of neuropathies in patients with type II diabetes mellitus.


Asunto(s)
Diabetes Mellitus Tipo 2/fisiopatología , Diabetes Mellitus Tipo 2/terapia , Neuropatías Diabéticas/fisiopatología , Neuropatías Diabéticas/terapia , Terapia por Ejercicio/métodos , Nervios Periféricos/fisiopatología , Reflejo , Anciano , Humanos , Masculino , Conducción Nerviosa , Resultado del Tratamiento
14.
J Cardiovasc Nurs ; 20(3): 177-85, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15870588

RESUMEN

Because individuals with claudication pain secondary to peripheral arterial disease (PAD) are limited in both walking speed and duration, the benefits of walking exercise may be insufficient to yield a cardiovascular training effect. The objectives of this analysis were to determine whether polestriding exercise training, performed by persons with PAD, would improve exercise endurance, elicit a cardiovascular training benefit, and improve quality of life (QoL). Persons (n = 49) whose claudication pain limited their exercise capacity were randomized into a 24-week polestriding training program (n = 25, 65.8 +/- 7.1 years of age) or a nonexercise attention control group (n = 24, 68.0 +/- 8.6 years of age). Those assigned to the polestriding group trained 3 times weekly. Control group subjects came to the laboratory biweekly for ankle blood pressure measurements. A symptom-limited ramp treadmill test, ratings of perceived leg pain, and QoL data (using the Short Form-36) were obtained at baseline and upon completion of training. After 24 weeks of polestriding training, subjects increased their exercise endurance from 10.3 +/- 4.1 minute to 15.1 +/- 4.5 minute. This was significantly greater than control group subjects whose exercise endurance declined (from 11.2 +/- 4.7 to 10.3 +/- 4.7 minute; P < .001). Relationships between systolic blood pressure (P < .001), heart rate (P = .04), rate pressure product (P = .05), oxygen uptake (P = .016), and perceived leg pain (P = .02) and exercise time improved from the baseline symptom-limited treadmill test to the 6-month symptom-limited treadmill test in the polestriding group compared to the control group. The improvement in the physical component summary score of the Short Form-36 was also greater in the polestriding group (P = .031). Polestriding training significantly improved the clinical indicators of cardiovascular fitness and QoL, and decreased symptoms of claudication pain during exertion.


Asunto(s)
Terapia por Ejercicio/métodos , Tolerancia al Ejercicio , Enfermedades Vasculares Periféricas/rehabilitación , Resistencia Física , Caminata , Anciano , Velocidad del Flujo Sanguíneo , Presión Sanguínea , Distribución de Chi-Cuadrado , Prueba de Esfuerzo , Terapia por Ejercicio/normas , Femenino , Estudios de Seguimiento , Frecuencia Cardíaca , Humanos , Masculino , Consumo de Oxígeno , Dimensión del Dolor , Enfermedades Vasculares Periféricas/diagnóstico por imagen , Enfermedades Vasculares Periféricas/fisiopatología , Enfermedades Vasculares Periféricas/psicología , Calidad de Vida , Encuestas y Cuestionarios , Factores de Tiempo , Resultado del Tratamiento , Ultrasonografía
15.
Phys Rev Lett ; 94(14): 147402, 2005 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-15904110

RESUMEN

We observe an efficient phase coherent photorefractive effect in ZnSe single quantum wells for ultrashort light pulses resonant to the excitonic transition. The effect is attributed to the formation of an electron grating in the quantum well induced by the interference of coherent excitons that preserve phase and polarization of the incident light fields. All characteristic features of the diffracted signal are explained and reproduced by numerical calculations that are based on the optical Bloch equations for a three-level system.

16.
Spinal Cord ; 43(6): 366-74, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15685261

RESUMEN

STUDY DESIGN: Survey research methods. OBJECTIVES: To assess patient satisfaction with the annual comprehensive preventative health evaluation (CPHE) and to determine if the patient's needs were being met. SETTING: Department of Veterans Affairs National Survey, United States. METHODS: A total of 853 subjects with spinal cord injuries participated in a mailed survey regarding the annual CPHE. Subjects were asked about satisfaction with the examination, preferences on how the examination is conducted and whether their needs were being met with the examination. RESULTS: In all, 76% of the subjects that responded to the survey had completed a CPHE within the previous year. Subjects cited getting their medication and supplies refilled and talking to the doctor as the top two reasons for completing the evaluation. Subjects indicated that they would most like to discuss their muscle strength and weakness, bladder care, chronic pain, digestion and bowel care issues, and equipment problems during their evaluation. The majority of subjects (81%) indicated that they were satisfied with the CPHE. Subjects that were satisfied with the CPHE were also more satisfied with other aspects of care as well. CONCLUSION: The majority of respondents had completed a CPHE within the previous year. Most respondents cite health issues related to the spinal cord injury as areas they would most like to discuss during the evaluation. The majority of subjects were satisfied with the conduct of the CPHE.


Asunto(s)
Actitud Frente a la Salud , Atención Integral de Salud/estadística & datos numéricos , Estado de Salud , Medicina Preventiva/estadística & datos numéricos , Traumatismos de la Médula Espinal/diagnóstico , Traumatismos de la Médula Espinal/epidemiología , Veteranos/estadística & datos numéricos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Investigación sobre Servicios de Salud , Humanos , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Encuestas y Cuestionarios , Estados Unidos/epidemiología
17.
Phys Rev Lett ; 95(26): 266401, 2005 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-16486377

RESUMEN

We present measurements and simulations of coherent control and readout of the polarization in individual exciton states. The readout is accomplished by transient four-wave mixing detected by heterodyne spectral interferometry. We observe Rabi oscillations in the polarization, which show half the period of the Rabi oscillations in the population. A decrease of the oscillation amplitude with pulse area is observed, which is not accompanied by a change in the dephasing time. This suggests the transfer of the excitation to other states as the origin of the Rabi-oscillation damping. Detuning of the excitation enables the control of the polarization in phase and amplitude and is in qualitative agreement with simulations for a two-level system. Additionally, simultaneous Rabi flopping of several spatially and energetically close exciton states is demonstrated.

18.
Am J Respir Crit Care Med ; 171(6): 598-605, 2005 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-15591465

RESUMEN

Hypogonadism, found in about one-third of patients with chronic obstructive pulmonary disease (COPD), has potential for decreasing muscle mass and muscle performance. Compared with eugonadal patients, we hypothesized that hypogonadal patients with COPD have decreased respiratory and skeletal muscle performance. Nineteen hypogonadal and 20 eugonadal men with COPD (FEV(1) 1.14 +/- 0.08 and 1.17 +/- 0.11 L [standard error], respectively) were studied. Diaphragmatic contractility, assessed as transdiaphragmatic twitch pressure generated by phrenic nerve stimulation, was similar in hypogonadal and eugonadal patients: 20.6 +/- 2.2 and 19.8 +/- 2.5 cm H(2)O, respectively. During progressive inspiratory threshold loading, hypogonadal and eugonadal patients had similar respiratory muscle endurance times (302 +/- 29 and 313 +/- 48 seconds, respectively) and airway pressure sustained during the last minute of loading (38.2 +/- 3.0 and 40.5 +/- 4.7 cm H(2)O, respectively) (similar to predicted values in healthy subjects). Hypogonadal and eugonadal patients had equivalent limb muscle strength and endurance. During cycle exercise to exhaustion, exercise performance, gas exchange, and respiratory muscle recruitment (estimated by esophageal and gastric pressure swings during tidal breathing) were similar in both groups. In conclusion, hypogonadism does not decrease respiratory or limb muscle performance and exercise capacity in men with moderate-to-severe COPD who, for the most part, are not underweight.


Asunto(s)
Hipogonadismo/fisiopatología , Músculo Esquelético/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Músculos Respiratorios/fisiopatología , Anciano , Estudios de Casos y Controles , Diafragma/fisiopatología , Estimulación Eléctrica , Prueba de Esfuerzo , Tolerancia al Ejercicio/fisiología , Humanos , Hipogonadismo/complicaciones , Masculino , Contracción Muscular/fisiología , Nervio Frénico/fisiología , Enfermedad Pulmonar Obstructiva Crónica/complicaciones
19.
Heart Lung ; 33(3): 154-61, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15136775

RESUMEN

PURPOSE: The purpose of this study was to determine whether subjects with chronic heart failure, who completed a 12-week rehabilitation program, would have significantly greater quality of life, better aerobic fitness, less difficulty with symptoms of heart failure, greater self-efficacy for exercise, and higher daily activity levels when compared with subjects in a control group. METHODS: Thirty-one males, aged 64 +/- 10 years with left ventricular ejection fraction of 29 +/- 7%, were randomized to a moderate intensity supervised aerobic exercise program (n = 15) or a control group (n = 16). Twenty-seven subjects completed at least 1 follow-up assessment. RESULTS: After 12 weeks there were significant differences in the change scores for perceived physical function (using RAND Corporation's 36-item short form) (P =.025) and peak oxygen uptake (P =.019) between the exercise and control groups with the exercise group experiencing improved physical function and fitness. CONCLUSIONS: Exercise training in adults with heart failure increases exercise tolerance and perceived physical function. Improved heart failure symptoms, self-efficacy for exercise, or increased physical activity may not be associated with enhancement of exercise tolerance.


Asunto(s)
Terapia por Ejercicio , Insuficiencia Cardíaca/rehabilitación , Consumo de Oxígeno/fisiología , Resistencia Física/fisiología , Anciano , Enfermedad Crónica , Prueba de Esfuerzo , Insuficiencia Cardíaca/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida , Autoeficacia , Perfil de Impacto de Enfermedad , Encuestas y Cuestionarios
20.
Med Sci Sports Exerc ; 35(3): 384-93, 2003 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-12618567

RESUMEN

PURPOSE: The purpose of this investigation was to evaluate the efficacy of PoleStriding exercise (a form of walking that uses muscles of the upper and lower body in a continuous movement similar to cross-country skiing) and vitamin E (alpha-tocopherol) to improve walking ability and perceived quality of life (QOL) of patients with claudication pain secondary to peripheral arterial disease (PAD). METHODS: Fifty-two subjects were randomized into four groups: PoleStriding with vitamin E (N = 13), PoleStriding with placebo (N= 14), vitamin E without exercise (N= 13), and placebo without exercise (N = 12). The dose of vitamin E was 400 IU daily. Only the PoleStriding with vitamin E and PoleStriding with placebo groups received PoleStriding instruction and training. Assignment to vitamin E or placebo was double blind. Subjects trained three times weekly for 30-45 min (rest time excluded). Individuals in vitamin E and placebo groups came to the laboratory biweekly for ankle blood-pressure measurements. RESULTS: Results of this randomized clinical trial provide strong evidence that PoleStriding significantly (P< 0.001) improved exercise tolerance on the constant work-rate and incremental treadmill tests. Ratings of perceived claudication pain were significantly less after the PoleStriding training program (P= 0.02). In contrast, vitamin E did not have a statistically significant effect on the subjects' ratings of perceived leg pain (P= 0.35) or treadmill walking duration ( P= 0.36). Perceived distance and walking speed (Walking Impairment Questionnaire) and perceived physical function (Rand Short Form-36) improved in the PoleStriding trained group only (P< 0.001, 0.022 and 0.003, respectively). CONCLUSION: PoleStriding effectively improved the exercise tolerance and perceived QOL of patients with PAD. Little additional benefit to exercise capacity was realized from vitamin E supplementation.


Asunto(s)
Terapia por Ejercicio , Pierna/irrigación sanguínea , Pierna/patología , Enfermedades Vasculares Periféricas/fisiopatología , Enfermedades Vasculares Periféricas/terapia , Vitamina E/uso terapéutico , Actividades Cotidianas/psicología , Anciano , Manejo de la Enfermedad , Método Doble Ciego , Prueba de Esfuerzo , Tolerancia al Ejercicio/efectos de los fármacos , Tolerancia al Ejercicio/fisiología , Femenino , Estudios de Seguimiento , Humanos , Illinois , Claudicación Intermitente/fisiopatología , Claudicación Intermitente/terapia , Masculino , Persona de Mediana Edad , Consumo de Oxígeno/efectos de los fármacos , Consumo de Oxígeno/fisiología , Cooperación del Paciente , Resistencia Física/efectos de los fármacos , Resistencia Física/fisiología , Estudios Prospectivos , Calidad de Vida/psicología , Ensayos Clínicos Controlados Aleatorios como Asunto , Flujo Sanguíneo Regional/efectos de los fármacos , Flujo Sanguíneo Regional/fisiología , Encuestas y Cuestionarios , Factores de Tiempo , Resultado del Tratamiento , Caminata/fisiología
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