Background: Few studies have dealt with the behavior of the corrected (QTc) and uncorrected QT intervals during exercise and recovery.
Hypothesis: Based on previously published dynamics of the QT ...interval during treadmill testing, this study attempted to reevaluate the computer‐proposed underlying mechanisms of these dynamics and to determine whether the so‐called memory phenomenon could be operative in some subjects without evidence of structural heart disease.
Methods: This study included 42 unmedicated healthcare volunteers, 23 men and 19 women aged between 20 and 42 (mean 31.7) years. All had normal physical examinations, x‐rays, and transthoracic echocardiograms. The electrocardiograms were also normal with 12‐lead QT interval dispersions of <90ms.
Results: During exercise and recovery, the behavior of the QT intervals permitted the categorization into two groups. In Group 1 (31/42; 73.8% of subjects) the uncorrected QT interval showed a biphasic pattern consisting of a gradual decrease during incremental exercise followed by a gradual increase during recovery. In contrast, the QTc interval had a triphasic pattern resulting from a slight increase during the early phase of exercise, a gradual decrease at the highest rates, and a final increase during recovery as the rate slowed to control values. In Group 2 (11/42; 36.2% of subjects) the behavior was considered as paradoxical since the uncorrected QT interval displayed in a triphasic pattern whereas the QTc interval yielded a tetraphasic pattern due to the fact that both showed a second decrease during recovery while the rate was decreasing.
Conclusions: Analysis of dynamics behavior of the QTc and the uncorrected QT intervals during exercise showed that some normal subjects had a paradoxical behavior which, because of its temporal relation to the phases of exercise, could be an expression of the so‐called memory phenomenon.
We sought to determine the prevalence and characteristics of echocardiographic abnormalities (systolic and/or diastolic dysfunction, pericardial effusion) in patients with human immunodeficiency ...virus infection (HIV) with no symptoms or previous history of cardiac disease, and compare them with a healthy control group.
Transthoracic echocardiography was performed in 125 patients (73% male, mean age 33.2 +/- 6.6 years) with HIV infection without cardiac involvement and 47 age and sex-matched healthy volunteers (78% male, 31.6 +/- 7.3 years). The immunologic situation was determined by CD4 lymphocyte counts.
Abnormal left ventricular relaxation and filling patterns (E/A relation 1.31 +/- 0.35 in HIV group, 1.66 +/- 0.38 in control group, p < 0.001; pressure half-time 57.5 +/- 13 in HIV group, 50.6 +/- 6.6 in control group, p < 0.001), segmental wall-motion abnormalities (15%) and pericardial effusion (7.2%) were found in patients with HIV infection. Systolic function (EF 64.8 +/- 8.3) and left ventricular dimension (diastolic diameter 4.94 +/- 0.55, systolic diameter 3.17 +/- 0.51) showed normal patterns and did not significantly differ from those of the control group.
Silent echocardiographic abnormalities in patients with HIV infection are frequent suggesting a direct myocardial effect of the virus. The development of diastolic dysfunction is directly related to a worse immunologic situation. Prospective studies are needed to clarify the clinical prognosis of these asymptomatic abnormalities.
The methylation status of the IGFBP-3 gene is strongly associated with cisplatin sensitivity in patients with non-small cell lung cancer (NSCLC). In this study, we found in vitro evidence that linked ...the presence of an unmethylated promoter with poor response to radiation. Our data also indicate that radiation might sensitize chemotherapy-resistant cells by reactivating IGFBP-3-expression through promoter demethylation, inactivating the PI3K/AKT pathway. We also explored the IGFBP-3 methylation effect on overall survival (OS) in a population of 40 NSCLC patients who received adjuvant therapy after R0 surgery. Our results indicate that patients harboring an unmethylated promoter could benefit more from a chemotherapy schedule alone than from a multimodality therapy involving radiotherapy and platinum-based treatments, increasing their OS by 2.5 y (p = .03). Our findings discard this epi-marker as a prognostic factor in a patient population without adjuvant therapy, indicating that radiotherapy does not improve survival for patients harboring an unmethylated IGFBP-3 promoter.
Se realizo un trabajo de investigacion, con el objeto de evaluar el comportamiento de ganancia de peso, conversion alimenticia en materia seca diaria, asi como la factibilidad economica por kilogramo ...de carne producido por concepto de alimentacion en toretes de engorda en corral, alimentados con dietas integrales que incluyeron el bagazo de aguacate. Se realizo con ganaderos cooperantes en la localidad de San Juanico, Municipio de Tinguindin, Michoacan, con una altitud sobre el nivel del mar de 1,600 metros, clima semicalido y subhumedo, precipitacion media anual de 700 mm. Y una temperatura media anual de 17 C. Durante los meses de Mayo-Agosto de 1997, se utilizaron 24 animales Bovinos machos holando-cebu, con un peso promedio inicial de 240 kilogramos, los cuales fueron distribuidos bajo un diseno completamente al azar entre tratamientos con 8 repeticiones cada uno. Los tratamientos consistieron en un testigo, el cual, se utilizo una dieta basal, segun las recomendaciones del NRS 94, para el T2, se incluyo 20 del bagazo de aguacate en substitucion del grano de sorgo para T3, el 30. El alimento y agua fue proporcionada a libre acceso, los animales fueron implantados, vacunados y desparasitados interna y externamente previamente. Los criterios de respuesta evaluados a los 84 dias de la prueba fueron: Ganancia de peso diaria, conversion alimenticia en relacion al consumo de materia seca y el costo de produccion del kilogramo de carne producido, por concepto de alimento. Los resultados muestran diferencias (P0.01), en la ganancia de peso diaria (1.69, 1.69 y 1.07 kg.) y conversion de alimento (6.09, 6.20 y 7.90 kg/kg.), en favor del tratamiento testigo y la inclusion del 20. Sin embargo, al obtener los costos de produccion, el tratamiento con la inclusion del 20 de bagazo de aguacate, mejoro significativamente (P0.05), en relacion al testigo y a la inclusion del 30 ($6.43, 5.83 y 6.85 M.N). Se concluye, que la inclusion de bagazo de aguacate en un 20 en la dieta, es factible ya que no presentaron alteraciones de rechazo y mejoraron en un 9 los costos de produccion en relacion al testigo. La inclusion del 30 presento mayores indices economicos , debido a la alta conversion registrada y se observo una disminucion al consumo, probablemente ocasionada por la baja palatividad del insumo utilizado
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