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ABSTRACT In order to increase the efficiency of maize hybrid seed production it is necessary to achieve a high grain yield to reduce production costs. This goal requires an expansion of the basic knowledge of the inheritance of characters in order to develop new breeding techniques to improve experimental materials with hard endosperm (flint). The balanced lethal system allows to study the relative contribution of different chromosome segments to hybrid vigour due to the heterozygosity of certain chromosome segments while the rest of the genome becomes homocygotic through continuous selfing. In this way, these segments can be transferred to inbred lines in order to increase grain yield or tassel size (to increase pollen production). The goal of this study was to transfer a heterotic segment by using a balanced lethal system regulated line (BLS14), through crosses and backcrosses, to S5 flint lines derived from two commercial hybrids, ACA 2000 and Cóndor with closed pedigree, with the objective of increase grain yield or tassel size for pollen production. The analysis of variance (ANOVA) and principal components analysis (PCA) showed a significant improvement in grain yield and tassel size in the S5 flint lines of both commercial hybrids, carrying the heterotic segment of the BLS14 line.

RESUMEN Para incrementar la eficiencia en la producción de semillas híbridas en maíz se necesitan altos rendimientos con un correlativo bajo costo de producción. Esto requiere una expansión de los conocimientos básicos de la herencia de caracteres que posibiliten desarrollar nuevas técnicas de mejoramiento sobre materiales experimentales de textura dura (flint). Los sistemas de letales balanceados permiten estudiar la contribución relativa de distintos segmentos heteróticos en el vigor híbrido dado que permiten lograr la heterocigosis cuasipermanente de una porción del genomio, mientras el resto del genoma se vuelve homocigota por autofecundaciones sucesivas. Estos sistemas pueden ser transferidos a líneas endocriadas para incrementar el rendimiento del grano y el tamaño de la panoja para aumentar la producción de polen. El objetivo de este trabajo fue incorporar un segmento heterótico de una línea regulada por un sistema de letales balanceados (BLS14), mediante cruzamiento y retrocruza, a líneas S5 derivadas de dos híbridos comerciales, ACA 2000 y Cóndor, de pedigree cerrado, con textura dura (flint), con la finalidad de aumentar el rendimiento en grano o el tamaño de la panoja para la producción de polen. Los análisis de variancia (ANOVA) y de componentes principales (ACP) mostraron un incremento significativo en el rendimiento del grano y el tamaño de la panoja de las líneas S5 de ambos híbridos comerciales, portando cada una de ellas el segmento heterótico proveniente de la línea BLS14.

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Myopia is a worldwide major public concern, aside from the visual disturbance needing optical correction, myopia may be associated with open angle glaucoma, retinal detachment and myopic maculopathy. The higher the myopia the higher the risk for retinal associated comorbidities, and the axial length is the more important measure to estimate risk of visual impairment. Recently a formula to predict axial length using spherical equivalent and keratometry was proposed, with the intention of categorizing the risk of visual impairment with Tideman et al. classification. PURPOSE: To evaluate the accuracy of an axial length prediction formula in a Colombian population 8-17 years old. METHODS: Children from MIOPUR study with optical biometer axial length measure (AL), manifest refraction and keratometry were included in the analysis. Predicted axial length (PAL) was calculated with the prediction formula. A Bland-Altman assessment was conducted, and the concordance correlation coefficient was measured. Proposed classification of AL to establish risk of visual loss was used with measured AL and with PAL. The percentage of eyes misclassified was then established. RESULTS: A total of 2129 eyes were included in the analysis. Mean difference of axial length (actual AL minus PAL) was -0.516 mm (-1.559 mm - 0.528 mm). Concordance correlation coefficient (CCC) of 0.656 (IC95 0.636-0.675) was found between the real AL and PAL. PAL differed from measured AL by 1 mm or more in 16.58 %, and by 2 mm or more, in 0.61 % of the eyes. In myopic eyes, PAL was in average 0.426 mm longer than the AL actually measured with CCC of 0.714 (IC95 0.666-0.761). PAL differed from measured AL by 1 mm or more in 21.92 %, and by 2 mm or more, in 0.45 % of the myopic eyes. The study revealed that 15.03 % of all eyes, and 29.81 % of myopic eyes, were misclassified when PAL was used. CONCLUSIONS: The proposed axial length prediction formula was not accurate, and it did not adequately classify risk of visual impairment in myopic eyes in a group of Colombian children. We consider that it is not possible to predict the axial length based only on optometric data, such as the corneal radius of curvature and the spherical equivalent. This is very possibly related to the variability of crystalline lens power within a population.

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Laparoscopic surgery is evolving to less invasive techniques. Thanks to new surgical advances, it is possible to insert into the abdominal cavity multiple instruments through a single device. One option is Triport®. We report two patients who underwent to an appendectomy and a cholecystectomy, respectively, performed through a single umbilical port. The procedures were successfully performed without complications. Patients were treated on an outpatient basis, according to the fast track concept. Therefore, single port laparoscopic transumbilical appendectomy and cholecystectomy are feasible and safe procedures that require proper training and specially designed surgical instruments.

Introducción: La cirugía laparoscópica se enfoca hacia el desarrollo de técnicas cada vez menos invasivas. Con el avance tecnológico es posible introducir a la cavidad abdominal múltiples instrumentos a través de un mismo puerto. Una de las opciones de acceso es el Triport®. Las experiencias con este método han sido procedimientos urológicos, ginecológicos y gastrointestinales. Métodos: Se describen una apendicectomía y una colecistectomía realizadas totalmente por vía laparoscópica a través de un puerto umbilical, utilizando el Triport®. Resultados: Las intervenciones se realizaron en forma exitosa, sin complicaciones intra ni postoperatorias. Ambos pacientes se trataron ambulatoriamente, según el esquema Fast-track de nuestro servicio. Conclusiones: La apendicectomía y colecistectomía por vía laparoscópica a través de un solo puerto transumbilical, son procedimientos factibles y seguros, que requieren de instrumental y entrenamiento adecuados.

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Diversas investigaciones han establecido la asociación entre enfermedades infeccionsas y parasitarias y enfermedad cerebrovascular. El objetivo de esta investigación fue establecer y caracterizar una posible asociación entre infección por Trypanosoma cruzi y enfermedad cerebrovascular en una población del oriente colombiano. Se utilizaron como grupos de referencia los pacientes atendidos en la Unidad de Diálisis del Hospital Ramón Gonzalez Valencia de Bucaramanga entre enero 1 y junio 30 de 1999. Se concluye que parece posible que la infección por T. cruzi esté en la génesis de la enfermedad cerebrovascular, al desencadenar fenómenos embólicos y de disfunción endotelial. Es recomendable realizar una investigación serológica en los pacientes con ECV en las regiones con alta prevalencia de infección por este parásito. Se requieren más estudios para caracterizar la asociación entre infección por T. cruzi y ECV

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The Maca (Lepidium meyenii) is a Peruvian hypocotyl that grows exclusively between the 3700 and 4500 masl at the Peruvian Andes. Traditionally it is attributed nutritional, energizing, fertilizing properties among others. With the purpose of evaluate scientifically the nutritional property of Maca, we carried out a controlled study in two generations of albino Swiss mice (parents and breeding). The parents were aleatorily assigned to one of three nutritional schedules. The food of each group was prepared based on powder from a commercial balanced food (CBF) of which 30% was replaced by raw or cooked Maca according to the corresponding group or pure CBF in the control group. The groups were this way: 1) Raw Maca Group; 2) Cooked Maca Group; and, 3) Control Group. The results showed that the curves of growth were similar and adequate for the three groups. However, the cooked Maca group showed the best curve. These data were better observable in the second generation of animals, with significant statistical difference (p < 0.05). The CBF group had a better growth than raw Maca group. No signs of malnutrition nor overweight were observed in none of the groups. The serum values of total proteins and albumin were statistically superior for the mice group eating cooked Maca than that of the raw Maca and CBF groups. This study demonstrates, in a scientifical evaluation, one of the traditionally attributed properties of Maca, the nutritional capability.

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The authors utilized a recently developed DNA probe technique to obtain quantitative data on occurrence of Vibrio cholerae in samples collected monthly from 12 environmental sites in Lima, Peru, from November 1993 through March 1995. Peak V. cholerae counts ranged from 10(2)/ml to 10(5)/ml, with the highest counts in sewage-contaminated areas and irrigation water. With our methodology, no V. cholerae cases were detected at any site during the winter months of July through October. Counts were detectable in the environment before onset of cholera in the community, with counts at "cleaner" sites upriver correlating significantly with occurrence of community disease 2 and 3 months later. In sites with heavy sewage contamination, V. cholerae could still be detected before the onset of cases in the community; however, in contrast to upriver sites, counts at these latter sites correlated most closely with the number of concurrently occurring cholera cases. These data support a model of cholera seasonality in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds.

PIP: A newly developed DNA probe technique was used to analyze the occurrence of Vibrio cholerae in samples collected from 12 environmental sites in metropolitan Lima, Peru, each month from November 1993 to March 1995. Epidemic V. cholerae cases were found in 69 (34.5%) of the 200 samples collected. This represents more than twice the number of cholera-positive samples correctly identified with traditional methods. The highest V. cholerae counts were recorded in sewage-contaminated areas and irrigation water. No V. cholerae cases were detected at any site during the winter months of July through October. At the relatively cleaner upriver sites, counts were detectable 2-3 months prior to the outbreak of disease in the community. In sites with heavy sewage contamination, counts were more closely correlated with the number of concurrently occurring cholera cases in the community. These findings provide evidence for a model of cholera seasonality, in which initial increases in number of V. cholerae in the environment (possibly triggered by temperature) are followed by an onset of illness in the community, with these human cases further amplifying the organism as the epidemic cycle proceeds. Enhanced understanding of the complex web of human and environmental interactions that lead to seasonal cholera outbreaks would facilitate the design of preventive interventions.

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Presentamos la experiencia inicial con la realización de 14 gastrostomias percutáneas con control fluoroscópico en el Servicio de Radiologia del Hospital Universitario San Vicente de Paul de Medellin, con elementos fácilmente disponibles y economicos. Se transcribe el procedimiento y se analizan indicaciones y morbimortalidad comparadas con un grupo de gastrostomias quirurgicas realizadas en la misma institucion. Concluimos que por su bajo costo, fácil aprendizaje y realización y baja morbilidad, la gastrostomia percutanea radiológica es una excelente alternativa para los pacientes que la requieran.

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We determined the prevalence and clinical features of rate-dependent distal renal tubular acidosis (dRTA) in 31 children examined for possible renal tubular acidosis by measuring the urinary-minus-blood partial pressure of carbon dioxide (U-B PCO2) gradient, minimal urinary pH, and fractional excretion of bicarbonate. Of 20 patients with low U-B PCO2 gradients, nine could not lower urinary pH < or = 5.5, indicating classic dRTA, whereas 11 could lower urinary pH < or = 5.5, as described in rate-dependent dRTA. When patients with rate-dependent dRTA and classic (type I) dRTA were compared, there was no difference in the mean U-B PCO2 gradient or in clinical findings, including age, reason for referral, presence of nephrocalcinosis, or depression of linear growth. We conclude that children with rate-dependent dRTA are susceptible to at least some of the same sequelae as children with classic dRTA. Measurement of minimal urinary pH will not detect this subtle form of dRTA. Determination of the U-B PCO2 gradient should be considered a routine part of evaluation for suspected renal tubular acidosis in a child.

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With the exception of C3 nephritic factor, autoantibody formation has not been commonly associated with membranoproliferative nephritis (MPGN). We measured autoantibodies (nephritic factors) to the C3 convertases C3bBb (NFa) and C3bBbP (NFt), which result in fast and slow C3 activation, respectively, and to a neoantigen on C1q fixed to a solid phase (spC1q) in sera from 29 patients with MPGN type I, 26 with type II, and 28 with type III. Autoantibody formation was common in all MPGN types. An autoantibody to a C3 convertase neoantigen was identified in more than 75% of the hypocomplementemic MPGN sera tested. Anti-C3bBb (NFa) was present in 81% of patients with MPGN type II but was rarely found in either type I or type III. Anti-C3bBbP (NFt) was common in both MPGN I and III. Anti-spC1q was present in 74% of patients with type I and in 38% and 48% of types II and III MPGN, respectively. Patients with MPGN types I, II, and III had one and two serum autoantibodies detected significantly more frequently than did a group of healthy subjects. The presence of any one autoantibody was not specifically associated with the presence of any other autoantibody. The results indicate that multiple autoantibody formation is common in all MPGN types. MPGN II, and possibly MPGN I, tend to form more specific autoantibodies.

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