Evolutionary learning of hierarchical decision rules.

This paper describes an approach based on evolutionary algorithms, hierarchical decision rules (HIDER), for learning rules in continuous and discrete domains. The algorithm produces a hierarchical set of rules, that is, the rules are sequentially obtained and must therefore be tried until one is found whose conditions are satisfied. Thus, the number of rules may be reduced because the rules could be inside of one another. The evolutionary algorithm uses both real and binary coding for the individuals of the population. We tested our system on real data from the UCI repository, and the results of a ten-fold cross-validation are compared to C4.5s, C4.5Rules, See5s, and See5Rules. The experiments show that HIDER works well in practice.

Infecciones por el virus parainfluenza tipo 4 / Parainfluenza virus type 4 infections

Objetivo: Describir las características clínicas y epidemiológicas de las infecciones por virus parainfluenza humano tipo 4 (VPIH-4) en pacientes pediátricos. Métodos: Se estudiaron los pacientes hospitalizados o atendidos en el servicio de urgencias con el diagnóstico de infección respiratoria de vías respiratorias inferiores. Las variables clínicas estudiadas fueron edad, sexo, diagnóstico clínico, temperatura corporal, saturación de oxígeno en sangre arterial (SaO2), resultado de la radiografía de tórax y duración de la hospitalización. Las muestras obtenidas mediante aspiración nasofaríngea se estudiaron mediante inmunofluorescencia indirecta (IFI), cultivo celular y una nueva técnica de reacción en cadena de la polimerasatranscripción inversa (RT-PCR) múltiple, capaz de detectar en la misma reacción los 4 tipos de virus parainfluenza. Resultados: Se analizaron 230 muestras correspondientes a 191 pacientes. En el 35,1% de los episodios se detectó algún virus parainfluenza: el 37,3% correspondió al VPIH-1, el 10,4% al VPIH-2, el 38,9% al VPIH-3 y en el 13,4% se identificó el VPIH-4. Se amplificó ARN del virus parainfluenza tipo 4 en 10 muestras correspondientes a 9 pacientes. Todos ellos excepto uno eran menores de 2 años, con unos límites de edad entre 26 días y 23 meses. El diagnóstico clínico fue bronquiolitis o bronquitis sibilante, que en uno de ellos se acompañó de infiltrado pulmonar. Precisaron ingreso hospitalario 6 pacientes, con una SaO2 media de 89,5% y una estancia media de 7,6 días. Discusión: Es la primera vez que se describe la circulación del VPIH-4 en España. Las infecciones ocasionadas por este virus no son tan leves como se había descrito inicialmente. La utilización de una RT-PCR múltiple permite diagnosticar infecciones respiratorias por VPIH-4 que de otra manera pasarían desapercibidas (AU)

[Parainfluenza virus type 4 infections]. / Infecciones por el virus parainfluenza tipo 4.

OBJECTIVE: To describe the clinical and epidemiological characteristics of parainfluenza virus type 4 infections in pediatric patients. METHODS: Inpatients and outpatients with lower respiratory tract infections were studied. Recorded data were age, sex, clinical diagnosis, temperature, oxygen saturation, chest radiograph and length of hospital stay. Nasopharyngeal aspirates were studied through indirect immunofluorescence, tissue culture and a new multiplex reverse-transcriptase polymerase chain reaction (RT-PCR) able to identify the four types of human parainfluenza virus in the same reaction. RESULTS: Two hundred thirty specimens from 191 patients were analyzed. Parainfluenza viruses were diagnosed in 35.1 %: 37.3 % type 1, 10.4 % type 2, 38.9 % type 3 and 13.4 % type 4. RNA from parainfluenza virus type 4 was amplified in 10 aspirates from nine patients. Of these, all except one were aged less than two years (range: 26 days to 23 months). The clinical diagnosis was bronchiolitis or wheezing associated with lower respiratory tract infection. Six patients required admission, with a mean oxygen saturation of 89.5 % and a mean length of hospital stay of 7.6 days. DISCUSSION: This is the first description of the characteristics of parainfluenza virus type 4 in Spain. Infections associated with this virus are not as mild as previously thought. Application of a multiplex RT-PCR allows identification of respiratory infections due to parainfluenza virus type 4 that would otherwise be underdiagnosed.

Infecciones virales de vías respiratorias inferiores en lactantes hospitalizados: etiología, características clínicas y factores de riesgo / Viral infection of the lower respiratory tract in hospitalized infants: etiology, clinical features and risk factors

Objetivos: Analizar las características clínicas y virológicas de las infecciones del tracto respiratorio inferior (ITRI) de los lactantes hospitalizados en nuestro medio y encontrar parámetros clínicos, analíticos o radiológicos que se relacionen, en el momento del ingreso, con una evolución más grave. Pacientes y métodos: Se realizó un estudio prospectivo de los niños menores de 24 meses ingresados por ITRI durante seis temporadas epidemiológicas consecutivas. Resultados: Se estudiaron 617 lactantes de los cuales el 64% presentaba bronquiolitis; el 24,6%, bronquitis espástica; el 4,4%, laringitis, y el 6,8%, neumonía. La edad media fue de 269 ± 188 días, la razón varón/mujer de 1,6 y la estancia media 6,6 ± 3,5 días. Se aisló al menos un agente viral en el 55,6% de los episodios, que en el 83,6% correspondió al virus respiratorio sincitial (VRS). Otros virus aislados con menor frecuencia fueron: para influenza (7 %), adenovirus (4,3%) e influenza (4%). Se detectaron coinfecciones en el 6,2% ciento de los casos VRS( ). Los niños VRS( ) tuvieron menor edad (p 38,5 °C y concentraciones de proteína C reactiva > 30 mg/l (p 6 (p < 0,003), SaO2 87 por ciento (p < 0,01) y aislamiento de VRS (p < 0,001). En el análisis multivariado sólo la SaO2 87% y la presencia de VRS se asociaron con hospitalización de más de 5 días. Conclusión: Las ITRI más frecuentes del lactante hospitalizado en nuestro medio son las bronquiolitis VRS( ), con características clínicas similares a las descritas en otros países. La hipoxia al ingreso y el aislamiento de VRS en aspirado nasofaríngeo son los factores de riesgo más importantes de hospitalización prolongada (AU)

[Viral infection of the lower respiratory tract in hospitalized infants: etiology, clinical features and risk factors]. / Infecciones virales de vías respiratorias inferiores en lactantes hospitalizados: etiología, características clínicas y factores de riesgo.

OBJECTIVES: The aim of this study was to assess the clinical and virological characteristics of lower respiratory tract (LRT) infection in hospitalized infants in Spain and to identify clinical, radiological or laboratory parameters that could, on admission, be associated with a more severe clinical course. PATIENTS AND METHODS: A prospective study of infants less than 24 months old hospitalized for LRT infection during six consecutive seasons was performed. RESULTS: A total of 617 infants were included in the study. Diagnosis was bronchiolitis in 64 %, wheezy bronchitis in 24.6 %, laryngitis in 4.4 % and pneumonia in 6.8 %. The mean age was 269 188 days, the male/female ratio was 1:6 and the mean hospital stay was 6.6 3.5 days. At least one viral agent was identified in 55.6 % of the episodes, of which 83.6 % were due to respiratory syncytial virus (RSV). Other less frequently identified viruses were parainfluenza in 7 %, adenovirus in 4.3 % and influenza in 4 %. Coinfection was identified in 6.2 % of RSV-positive infants. These infants were younger (p < 0.005), had higher respiratory distress assessment instrument (RDAI) scores and longer hospital stay than infants in the other etiologic groups. Chest radiographs were performed in 94.3 % of the infants and 39.5 % showed infiltrate or atelectasis. This radiological alteration was significantly associated with a fever of more than 38.5 C and reactive C protein concentrations of more than 30 mg/L (p < 0.001 and p < 0.002), but not with higher RDAI score, SaO2 equal to or less than 87 %, or longer hospital stay. In the crude analysis, hospitalization for more than 5 days was associated with lower age (p < 0.01), a mean RDAI score of more than 6 (p < 0.003), SaO2 equal to or less than 87 % (p < 0.01) and RSV infection (p < 0.001). However, in the multivariate analysis only SaO2 equal to or less than 87 % and RSV infection were significantly associated with prolonged hospitalization. CONCLUSION: The most common lower respiratory tract infections in hospitalized infants in Spain are the various types of RSV-positive bronchiolitis, which have a clinical pattern similar to that described in other countries. Hypoxia on admission and RSV infection are the most important risk factors for prolonged hospitalization.

[Densitometric study of staghorn lithiasis using computerized tomography]. / Estudio densitométrico de la litiasis coraliforme mediante tomografía computarizada.

Fifty staghorn calculi that had been removed surgically and previously analyzed for stone composition and structure were studied by tomodensitometry. The analysis consisted of measurements in absolute units and histographic configuration of x-ray attenuation-absorption of the lithiasic material. The reconstructed images were evaluated and the areas of interest were defined. Each section and area had the following universal elements: number of pixels studied and values for mean attenuation expressed as Hounsfield units (HU). In this manner, tomodensitometric mapping of the calculi could be performed. We underscore the usefulness of this procedure in investigation and the possibility of extrapolating the results to in vivo studies of calculi composition so that we can reliably predict the results attainable with treatment modalities such as ESWL or percutaneous surgery. Little has been published on this subject. To our knowledge, this is the first in Spain.

[Seasonal effect of age, sex and drinking water composition on nephritic colic]. / Influencias estacionales de la edad, sexo y composición del agua bebida sobre los cólicos nefríticos.

The influence of the season, age, sex and composition of the drinking water on the incidence of kidney colics in patients of different villages, attended at the "San Cecilio" Clinical Hospital in Granada, is assessed. The average, of kidney colics per 1.000 inhabitants was 4.2% with 51.27% in females and 48.73% in males. We found that in the summer months the frequency of kidney colics was double that in the winter months, which may be due to a relative D hypervitaminosis, a greater intake of oxalates or a relative dehydration. No influence of the calcium, magnesium, chlorine and sulphate contents of the water, was detected. In some villages, a high calcium and magnesium content in the water, posed problems for the urolithogenic prophylaxis in some patients.

[Clinical behavior of mixed nucleus reno-ureteral calculi]. / Comportamiento clínico de los cálculos renoureterales de núcleo mixto.

We made a statistical study, by means of a computer, of 87 crystallographically-analysed stones, corresponding to 85 patients, assessing different clinical data with the mixed composition of the nucleus of these stones. We deduce that in general, the behaviour of these stones is determined by the interaction of their components, with the main substance predominating. The most significant correlations were obtained when we assessed the sex, age, urinary infection, simple or coralliform morphology of the stone, the number of stones formed, permanent, homolateral, kidney damage, overall kidney failure and procedure for removing the stone. We did not find any valid links when we compared the family record of lithiasis, affectation of the counterlateral kidney and the fact whether the stone was from the right or the left.

[Ultrastructure of primary or endogenous prostatic calculi. Scanning electron microscopic study]. / Ultraestructura de los cálculos prostáticos primarios o endógenos. Estudio al microscopio electrónico de barrido o "scanning".

We make an analysis by means of a Scanning Electromicroscope, of the ultrastructure of 15 Primary Prostate stones. The components identified were: Carboapatite in 14 stones, Hydorxyapatite in 3, Whitlockite in 4 and Wedellite in 2 stones. The ultrastructural findings have enabled us to classify them as follows: 1. Hydroxyapatite stones, which we call "Crystalline", the rarest, due to the predominance of the inorganic component. 2. Carboapatite stones, which possess a great deal of organic material and which we subdivide into "Amylaceous" for those which possess some ovoid formations which appear to us to correspond to amylaceous bodies and "non-amylaceous" for those without them.

A crystallographic study of prostatic calculi.

We analyzed 70 prostatic calculi using crystallographic methods and determined the individual composition of the layers, structures and ultrastructures, thus, obtaining a more precise classification of these calculi.

[Mixed-nucleus renal calculi]. / Cálculos renales de nucleo mixto.

We made a crystallographic analysis of 87 mixed-nucleus stones and found 4 groups of stones of this kind, which are as follow: urico-oxalic, oxalico-uric, phosphato-oxalic and oxalic-phosphatic. We did not find any mixed-nucleus, urico-phosphatic or phosphatico-uric stones and we explain this fact according to the known lithogenic, metabolic mechanisms, in which urinary pH has an important function.

[Evaluation of 7 methods of analysis of urinary calculi]. / Valoración de siete métodos de análisis de calculos urinarios.

We assess seven methods of analysing urinary stones which we have used to study a total of 893 cases of lithiasis. For the purpose of a routine identification of the components, we consider the Immersion Method to be the best technique, followed by X-Ray Diffraction or Infrared Spectroscopy. We reject Scanning, qualitative, chemical analysis and quantitative, chemical analysis because of their drawbacks. For research purposes, we favour the "fine plate" supported by X-Ray Diffraction and Infrared Spectroscopy.