ABSTRACT
La vigilancia epidemiológica provee información actualizada y oportuna sobre los problemas de salud y sus condicionantes, lo que permite definir acciones de prevención y control. Para la detección de epidemias es útil disponer de corredores endémicos, que indican el número de casos esperados para un cuadro infeccioso en un momento determinado. Con datos de la sección Microbiología del Hospital de Niños "Dr. Pedro de Elizalde" acerca de pacientes internados con diagnóstico de infección respiratoria aguda baja (IRAB) entre el 1/1/96 y el 31/12/2002 se confeccionaron los corredores para influenza A (IA) por semanas epidemiológicas, correspondientes a un período de siete años. En ese período se internaron 10.473 niños con diagnóstico de IRAB y se identificó IA en 411 aspirados nasofaríngeos. Se calcularon la media y el intervalo de confianza de 95% para los límites superior e inferior de incidencia en períodos semanales, y se encontró que el pico estacional ocurre entre las semanas 25 y 32. Al analizar los datos del año 2003, se observó que el pico se produjo antes, entre las semanas 19 y 25, y con valores muy por encima de los esperados para esas semanas. En 2004 aparecen 2 picos, el primero en la semana 20 y sin superar los valores de fluctuación de la parte central de la curva, y el segundo en la semana 26.
Epidemiological surveillance provides updated information about health problems which allows for the establishment of health policy guidelines. The methods for detecting the epidemic frequency of disease require the systematic collection of data on the occurrence of specific diseases. Influenza has cyclic seasonal peaks and its endemic baseline rates are useful for identifying outbreaks: the comparison between baseline and current data supplies epidemiological evidence related to an ongoing outbreak. The upper and lower incidence curves were traced for the data referring to IA detection in the nasopharyngeal aspirates from children hospitalized for acute lower respiratory tract infection from 1996 to 2002. The arithmetic mean and the 95% confidence interval for upper and lower limits of weekly incidence were calculated. The highest incidence was observed between weeks 25 and 32. When analyzing the prepared endemic corridor, it was observed that the highest detection in 2003 occurred between weeks 19 and 25, whereas two peaks occurred in 2004 , the first starting at week 20, at a lower level than the normal epidemic peak, and the second at week 26.
Subject(s)
Child , Child, Preschool , Humans , Infant , Infant, Newborn , Influenza, Human/epidemiology , Influenza, Human/virology , Population Surveillance/methods , Respiratory Tract Infections/virology , Seasons , Argentina/epidemiology , IncidenceABSTRACT
Estrogen stimulates the renin-angiotensin system by augmenting both tissue and circulating levels of angiotensinogen and renin. We show, however, that angiotensin converting enzyme (ACE) activity in the circulation and in tissues is reduced in two animal models of postmenopausal chronic hormone replacement. We observed a reduction of ACE activity in association with a significant increase in plasma angiotensin I (Ang I) and hyperreninemia in ovariectomized monkeys treated with Premarin (conjugated equine estrogen) replacement for 30 months. Plasma angiotensin II (Ang II) levels were not increased in monkeys treated with estrogen, suggesting that the decrease in ACE curtailed the formation of the peptide. The Ang II/Ang I ratio, an in vivo index of ACE activity, was significantly reduced by estrogen treatment, further supporting the biochemical significance of estrogen's inhibition of ACE. In ovariectomized transgenic hypertensive (mRen2)27 rats submitted to estrogen replacement treatment for 3 weeks, ACE activity in plasma and tissue (aorta and kidney) and circulating Ang II levels were reduced, whereas circulating levels of angiotensin-(1-7) (Ang-(1-7) were increased. Ang-(1-7), the N-terminal fragment of Ang II, is a novel vasodilator and antihypertensive peptide. Thus, the net balance of these effects of estrogen on the renin-angiotensin vasoconstrictor/vasodilator system is to promote the antihypertensive effect.