Use of variability in national and regional data to estimate the prevalence of lymphangioleiomyomatosis.

BACKGROUND: Understanding the true prevalence of lymphangioleiomyomatosis (LAM) is important in estimating disease burden and targeting specific interventions. As with all rare diseases, obtaining reliable epidemiological data is difficult and requires innovative approaches. AIM: To determine the prevalence and incidence of LAM using data from patient organizations in seven countries, and to use the extent to which the prevalence of LAM varies regionally and nationally to determine whether prevalence estimates are related to health-care provision. METHODS: Numbers of women with LAM were obtained from patient groups and national databases from seven countries (n = 1001). Prevalence was calculated for regions within countries using female population figures from census data. Incidence estimates were calculated for the USA, UK and Switzerland. Regional variation in prevalence and changes in incidence over time were analysed using Poisson regression and linear regression. RESULTS: Prevalence of LAM in the seven countries ranged from 3.4 to 7.8/million women with significant variation, both between countries and between states in the USA. This variation did not relate to the number of pulmonary specialists in the region nor the percentage of population with health insurance, but suggests a large number of patients remain undiagnosed. The incidence of LAM from 2004 to 2008 ranged from 0.23 to 0.31/million women/per year in the USA, UK and Switzerland. CONCLUSION: Using this method, we have found that the prevalence of LAM is higher than that previously recorded and that many patients with LAM are undiagnosed.

Estudio preliminar sobre la presencia de arbovirus en poblaciones de Corrientes y Misiones / Preliminary study on the presence of arbovirus in the populations of Corrientes and Misiones

Con la intención de localizar y medir la prevalencia de anticuerpos contra Flavivirus se analizaron por la técnica de inhibición de la hemoaglutinación 479 sueros provenientes de personas que habitan el territorio misionero de la República Argentina y 49 sueros humanos de la provincia de Corrientes. Se estudiaron localidades ribereñas con un tránsito importante con Paraguay y/o Brasil, con el objeto de verificar la posible introducción del Dengue desde estos países. En Ituzaingó (Corrientes) se encontraron dos sueros positivos para Dengue 2. En Misiones se encontraron 3 sueros positivos en Oberá y 2 en Montecarlo para Dengue 2 mientras que en Puerto Iguazú un suero fue reactivo contra Dengue. 1. La seroprevalencia en las poblaciones ribereñas fue significativamente mayor al de las poblaciones de montaña. Las poblaciones sobre el río Uruguay. El 54% de los sueros presentó mayor reactividad para SLE que para FA y Dengue. En los sueros de Misiones se analizaron, a su vez, los anticuerpos contra los alfa-virus EEE y WEE; se observó un patron de distribución complementario con respecto a los flavivirus, siendo mayor la seroprevalencia en las poblaciones de montaña y, dentro de las rivereñas, en las del río Uruguay

Airway pressure changes observable with constant-flow inflation and an end-inspiratory pause.

Constant-flow inflation and a prolonged end-inspiratory pause were studied, observing the airway pressures in model lungs. The technique demonstrated the changes associated with compliance, resistance and gas redistribution under varying conditions. The studies suggest that when intratracheal pressures indicate a large element of gas redistribution, constant flow inflation and end-inspiratory pause produce pendelluft, and other pressure patterns are preferable for I.P.P.V.

Respiratory mechanics with constant flow inspiration. A comparison of two measurement techniques.

Resperatory compliance and resistance were measured during positive pressure ventilation in anaesthtized, paralysed dogs. Airway pressures measured during constant-flow inspiration allowed the calculation of pulmonary and chest-wall resistances, and static and non-static compliances. Contiguous studies of dynamic compliance and resistance allowed comparison of the two techniques, and the level of agreement was reasonalble. Cconstant-flow inflation of the lungs allows a simple means of measuring respiratory mechanics, and should be valid for the observation of short-term changes in the apnoeic patient.