Quality of Life in Patients with Background of Iatrogenic Bile Duct Injury.

BACKGROUND: There are only a few reports regarding the quality of life of patients who underwent a complicated cholecystectomy with an iatrogenic bile duct injury (IBDI); the results have been heterogeneous and realized with unspecific measures. METHODS: The objective was to determine whether the quality of life of the subjects with a history of IBDI repaired with bilioenteric derivation is modified in the long term with respect to a control group, for which a group of patients with a history of IBDI (group A) was compared with a group of patients with a history of uncomplicated cholecystectomy (group B). Two different measures were used: on the one hand, the SF-12 questionnaire and on the other hand, a questionnaire was implemented where the patient could determine by himself which variables define his quality of life. RESULTS: A total of 46 patients were included in group A and 51 in group B. The analysis of the SF-12 questionnaire showed a statistical significant reduction in 4 of 8 of the evaluated parameters (general health, physical functioning, physical role and social functioning) in group A in comparison with group B. If a more specific questionnaire is used, the results are similar, with a statistically significant reduction in the quality of life within the group A (0.03). CONCLUSIONS: We conclude that the quality of life of patients with a history of bilioenteric derivation due to an IBDI decreases significantly compared to patients with uncomplicated cholecystectomy.

Acute leukemia classification by ensemble particle swarm model selection.

OBJECTIVE: Acute leukemia is a malignant disease that affects a large proportion of the world population. Different types and subtypes of acute leukemia require different treatments. In order to assign the correct treatment, a physician must identify the leukemia type or subtype. Advanced and precise methods are available for identifying leukemia types, but they are very expensive and not available in most hospitals in developing countries. Thus, alternative methods have been proposed. An option explored in this paper is based on the morphological properties of bone marrow images, where features are extracted from medical images and standard machine learning techniques are used to build leukemia type classifiers. METHODS AND MATERIALS: This paper studies the use of ensemble particle swarm model selection (EPSMS), which is an automated tool for the selection of classification models, in the context of acute leukemia classification. EPSMS is the application of particle swarm optimization to the exploration of the search space of ensembles that can be formed by heterogeneous classification models in a machine learning toolbox. EPSMS does not require prior domain knowledge and it is able to select highly accurate classification models without user intervention. Furthermore, specific models can be used for different classification tasks. RESULTS: We report experimental results for acute leukemia classification with real data and show that EPSMS outperformed the best results obtained using manually designed classifiers with the same data. The highest performance using EPSMS was of 97.68% for two-type classification problems and of 94.21% for more than two types problems. To the best of our knowledge, these are the best results reported for this data set. Compared with previous studies, these improvements were consistent among different type/subtype classification tasks, different features extracted from images, and different feature extraction regions. The performance improvements were statistically significant. We improved previous results by an average of 6% and there are improvements of more than 20% with some settings. In addition to the performance improvements, we demonstrated that no manual effort was required during acute leukemia type/subtype classification. CONCLUSIONS: Morphological classification of acute leukemia using EPSMS provides an alternative to expensive diagnostic methods in developing countries. EPSMS is a highly effective method for the automated construction of ensemble classifiers for acute leukemia classification, which requires no significant user intervention. EPSMS could also be used to address other medical classification tasks.

Availability of vitamin D photoconversion weighted UV radiation in southern South America.

Ultraviolet radiation (UVR) plays a key role in several biological functions, including human health. Skin exposure to UVR is the main factor in vitamin D photoconversion. There is also evidence relating low levels of vitamin D with certain internal cancers, mainly colon, breast and prostate, as well as other diseases. Several epidemiological studies have shown an inverse relationship between the above-mentioned diseases and latitude, in accordance with the ultraviolet radiation latitudinal gradient. The aim of this study is to determine whether UV irradiance levels in the southern South America are sufficient to produce suitable levels of vitamin D year around. For this purpose, vitamin D photoconversion weighted-irradiance was analyzed between S.S. de Jujuy (24.17°S, 65.02°W) and Ushuaia (54° 50'S, 68° 18'W). In addition to irradiance, skin type and area of body exposed to sunlight are critical factors in vitamin D epidemiology. Due to a broad ethnic variability, it was assumed that the skin type in this region varies between II and V (from the most to the less sensitive). All sites except South Patagonia indicate that skin II under any condition of body area exposure and skin V when exposing head, hands, arms and legs, would produce suitable levels of vitamin D year round (except for some days in winter at North Patagonian sites). At South Patagonian sites, minimum healthy levels of vitamin D year round can be reached only by the more sensitive skin II type, if exposing head, hands, arms and legs, which is not a realistic scenario during winter. At these southern latitudes, healthy vitamin D levels would not be obtained between mid May and beginning of August if exposing only the head. Skin V with head exposure is the most critical situation; with the exception of the tropics, sun exposure would not produce suitable levels of vitamin D around winter, during a time period that varies with latitude. Analyzing the best exposure time during the day in order to obtain a suitable level of vitamin D without risk of sunburn, it was concluded that noon is best during winter, as determined previously. For skin type II when exposing head, exposure period in winter varies between 30 and 130 min, according to latitude, except for South Patagonian sites. During summer, noon seems to be a good time of day for short periods of exposure, while during leisure times, longer periods of exposure without risk of sunburn are possible at mid-morning and mid-afternoon. At 3 h from noon, solar zenith angles are almost the same for sites between the tropics and North Patagonia, and at 4 h from noon, for all sites. Then, in these cases, the necessary exposure periods varied slightly between sites, only due to meteorological differences.

Quality of UVR exposure for different biological systems along a latitudinal gradient.

The exposure of organisms to ultraviolet radiation (UVR) is characterized by the climatology (annual cycle) and the variance (anomalies) of biologically-weighted irradiances at eight geographical locations in austral South America, from 1995-2002. The net effect of UVR on biological systems is a result of the balance of damage and repair which depends on intensity and duration of irradiance and is modulated by its variability. The emphasis in this study is on day-to-day variability, a time scale of importance to adaptive strategies that counteract UVR damage. The irradiances were weighted with DNA- and phytoplankton photosynthesis-action spectra. Low latitude sites show high average UVR. For all sites, the frequency of days with above average irradiances is higher than below average irradiances. Persistence in anomalies is generally low (

Global spectral UV-radiometer with automatic shadow band.

A solar radiometer (GUV-511 C, Biospherical Instruments Inc., San Diego, CA) with four UV channels has been operating at Trelew (43.2 degrees S, 65.3 degrees W), Argentina, since the austral spring of 1997. The instrument provides global (direct + diffuse) irradiance on the horizontal plane year-round, with a 1 min period. On 1 January 1999, an automatic shadow band was added to calculate diffuse and direct radiation. The period of the measurements was increased to 2 min to keep the same signal to noise (S:N) ratio. Once the direct radiation values were available for the 305 nm and 320 nm spectral bands, the total ozone value was calculated and results were compared with data provided by the U.S. National Aeronautics and Space Administration for the Total Ozone Mapping Spectrometer (TOMS) on the Earth Probe satellite. Results show a root-mean-square (RMS) deviation within 4% compared with that of TOMS, so the quality of results is considered to be quite good. The importance of regular calibration to maintain long-term accuracy is stressed.

Multichannel radiometer calibration: a new approach.

The error in irradiance measured with Sun-calibrated multichannel radiometers may be large when the solar zenith angle (SZA) increases. This could be particularly detrimental in radiometers installed at mid and high latitudes, where SZAs at noon are larger than 50 degrees during part of the year. When a multiregressive methodology, including the total ozone column and SZA, was applied in the calculation of the calibration constant, an important improvement was observed. By combining two different equations, an improvement was obtained at almost all the SZAs in the calibration. An independent test that compared the irradiance of a multichannel instrument and a spectroradiometer installed in Ushuaia, Argentina, was used to confirm the results.

Un estudio prospectivo, comparativo y aleatorio de escleroterapia variceal contra ligadura variceal en el tratamiento de la hemorragia por várices esofágicas / Sclerotherapy vs band ligation in variceal non-active bleeding

Objetivo: Determinar cuál método endoscópico terapéutico: Ligadura Variceal (LV) vs Escleroterapia Variceal (ESV) es superior en la erradicación de Várices Esofágicas (VE). Así como la incidencia de hemorragia recurrente temprana, complicaciones, mortalidad, y recurrencia variceal. Material y métodos: Fueron incluidos en el estudio, durante el periodo de Enero a Junio de 1999, a pacientes con cirrosis hepática y antecedente de episodio reciente de hemorragias por VE. Se asignó en forma aleatoria el método de tratamiento endoscópico a realizar: LV o ESV. Todos los pacientes tuvieron un seguimiento mínimo de tres meses posterior al inicio de la primera sesión terapéutica. Se clasificó a los pacientes de acuerdo al grado de disfunción hepática según la clasificación de Child-Pugh. Se analizaron los eventos de hemorragia recurrente temprana, erradicación, recurrencia variceal, falla en el tratamiento y complicaciones del método endoscópico. Los procedimientos terapéuticos se realizaron con Videogastroscopio marca Pentax modelo EG 2901. Para la ESV, se utilizó un inyector para VE 4fr, en la ligadura variceal se utilizó el ligador múltiple Saeed Six Shooter de la compañía Wilson-Cook. Resultados: Fueron incluidos en el estudio 48 pacientes; 23 de éstos recibieron ESV y 25 LV. Ambos grupos tuvieron datos clínicos, demográficos, reserva funcional hepática, grado de várices esofágicas y tiempo de seguimiento similares. Se logró la erradicación variceal en 17 pacientes (74 por ciento) en el grupo que recibió ESV y en 23 pacientes (92 por ciento) que recibió LV. La hemorragia recurrente temprana se presentó en 26 por ciento del grupo que recibió ESV y en 16 por ciento en el grupo de LV. El índice de recurrencia variceal fue mayor en el grupo de LV (52 por ciento vs 30 por ciento). Las complicaciones y mortalidad fueron similares en ambos grupos con una baja incidencia. Conclusiones: La técnica de LV presentó mayor efectividad en la erradicación variceal y necesitó menor número de sesiones, sin embargo hubo mayor incidencia de recurrencia variceal que en el grupo ESV.