Auditory filter shapes derived from forward and simultaneous masking at low frequencies: Implications for human cochlear tuning.

Behavioral forward-masking thresholds with a spectrally notched-noise masker and a fixed low-level probe tone have been shown to provide accurate estimates of cochlear tuning. Estimates using simultaneous masking are similar but generally broader, presumably due to nonlinear cochlear suppression effects. So far, estimates with forward masking have been limited to frequencies of 1 kHz and above. This study used spectrally notched noise under forward and simultaneous masking to estimate frequency selectivity between 200 and 1000 Hz for young adult listeners with normal hearing. Estimates of filter tuning at 1000 Hz were in agreement with previous studies. Estimated tuning broadened below 1000 Hz, with the filter quality factor based on the equivalent rectangular bandwidth (QERB) decreasing more rapidly with decreasing frequency than predicted by previous equations, in line with earlier predictions based on otoacoustic-emission latencies. Estimates from simultaneous masking remained broader than those from forward masking by approximately the same ratio. The new data provide a way to compare human cochlear tuning estimates with auditory-nerve tuning curves from other species across most of the auditory frequency range.

El género femenino como factor predictivo en los resultados de la endarterectomía carotídea / Female gender as a predictive factor in the outcome of carotid endarterectomy

Introducción: Existe evidencia contradictoria acerca del beneficio de la endarterectomía carotídea (EC) en la mujer. Objetivo: Evaluar si el género femenino afecta los resultados inmediatos y alejados de la EC. Material y método: Estudio retrospectivo de 346 EC realizadas entre Enero de 1990 y Julio de 2008 en el Hospital Guillermo Grant Benavente de Concepción. Del total, 137 EC fueron realizadas en mujeres. Como grupo control se consideró a los hombres operados en el mismo período, quienes presentaron características demográficas y otras variables potencialmente adversas en proporción similar a las mujeres. Todas las variables se analizaron en un estudio bivariado y multivariado. Se comparó la morbimortalidad operatoria AVC/muerte), la sobrevida global a 5 y 10 años, el intervalo libre de eventos neurológicos y de reestenosis a 5 años. Se utilizó el método de Kapplan-Meier para la sobrevida actuarial, el Test de Log Rank y Chi Cuadrado para la significación estadística y la regresión logística (Backward Stepwise) para el análisis multivariado. Los resultados alejados se expresan en sobrevida promedio + error estándar. Resultados: El género femenino no mostró ser una variable independiente negativa para los resultados de la EC. La incidencia de AVC/muerte en las mujeres fue 1,5 por ciento.(hombres: 1,4 por ciento) (p= NS). La sobrevida global a 5 y 10 años fue 82,5 por ciento +/- 4,1 y 49,7 por ciento +/- 9,7, respectivamente (hombres: 73,5por ciento + 4,0 y 45 por ciento +/- 7,8) (p= NS). A 5 años, el intervalo libre de eventos neurológicos fue 97 por ciento +/- 1,8 (hombres: 98,3 por ciento +/- 1,0) (p= NS) y el de reestenosis fue 93,9 por ciento +/- 3,6 (hombres: 98,5 por ciento +/- 1,1) (p= NS). Conclusión: El género femenino no afecta los resultados de la EC por lo que no se debe considerar un factor predictivo adverso.

Background: The benefits of carotid endarterectomy (CE) in women have been questioned Aim: to evaluate whether female gender influences the results of CE Methods: 346 procedures of CE performed between January 1990 and July 2008 at Hospital Guillermo Grant Benavente in Concepcion were restrospectively analyzed. 137 CE were performed in women. Demographic characteristics were similar between males and females. A university and multi variate analysis including other adverse factors influencing the results of surgery was performed. Operative morbidity and mortality, global survival, neurologic events free survival and the re stenosis rate at 5 years were analyzed. Actuarial survival was analyzed by the Kapplan-Meir procedure using the Log-rank and Chi square tests; Backward stepwise logistic regression was used in multivariate analysis. Results: Female gender was not found to be an independent risk factor for poorer outcomes of CE. Stroke plus total death in woman was 1,5 percent, versus 1,4 percent in man (P=NS). Survival in woman at 5 and 10 years was 82,5 percent +/- 4,1 and 49,7 percent +/- 9,7, respectively, whereas in man it was 73,5 percent +/- 4,0 and 45 percent +/- 7,8) (p NS). At 5 years follow-up 97 percent +/- 1,8 of woman versus 98,3 percent +/- 1,0 of men were free of neurological events; free of having restenosis were 93,9 percent +/- 3,6 of woman versus 98,5 percent +/- 1,1 of man (p= NS). Conclusion: female gender did not result in poorer results following CE and, therefore, should not be considered an adverse predictive factor for this surgical procedure.

[Peptic stricture of the esophagus: long term outcome of conservative treatment]. / Estenosis péptica del esófago: resultados alejados del tratamiento conservador.

BACKGROUND: Endoscopic dilatation of esophageal strictures is a simple and safe procedure. AIM: To analyze the long term outcome of conservative treatment for esophageal peptic stricture in patients with high surgical risk. PATIENTS AND METHODS: Twenty consecutive patients, 13 male, whose mean age was 75.2 years, with a peptic stricture of the esophagus and high surgical risk were prospectively studied. All were subjected to endoscopic esophageal dilatation and treated with continuous medical antireflux therapy thereafter. RESULTS: Only five patients complied with antireflux treatment on a regular basis. The remaining 15 were non compliant or abandoned it. A total of 56 dilatations were done (mean 2.8 per patient, range 1-6). No complications were observed after the procedure. With a mean follow up period of 49 months, the outcome of the conservative treatment was classified as excellent or good in all the cases. Eight patients (40%) died of causes unrelated to the treatment. Two patients had an organic foreing body impactation. This situation was solved endoscopically in both. CONCLUSION: In high risk patients, endoscopic dilatation, with or without regular antireflux medical treatment is a simple, safe and effective therapy in the management of peptic oesophagel stenosis.