Aptamers as a novel diagnostic and therapeutic tool and their potential use in parasitology / [Los aptámeros como novedosa herramienta diagnóstica y terapéutica y su potencial uso en parasitología].

Aptamers are single-stranded DNA or RNA sequences that adopt unique three-dimensional structures that allow them to recognize a specific target with high affinity. They can potentially be used for the diagnosis of diseases, as new therapeutic agents, for the detection of food risks, as biosensors, for the detection of toxins, and as drug carriers and nanoparticle markers, among other applications. To date, an aptamer called pegaptanib is the only aptamer approved by the Food and Drug Administration (FDA) for commercial use. Other aptamers are in different clinical stages of development for the treatment of different diseases. In parasitology, investigations carried out with parasites such as Leishmania spp. allowed the acquisition of aptamers that recognize the polyA-binding protein LiPABP and may have potential applications in research and diagnosis and even as therapeutic agents. Regarding malaria, aptamers have been obtained that allow the identification of infected erythrocytes or inhibit the formation of rosettes, along with those that provide promising alternatives for diagnosis by specifically detecting the protein lactate dehydrogenase (PfLDH). In Cryptosporidium parvum allow the detection of oocysts in contaminated food or water. In Entamoeba histolytica, two aptamers called C4 and C5, which inhibit the proliferation of trophozoites in vitro and have potential use as therapeutic agents, have been isolated. Aptamers obtained against Trypanosoma cruzi inhibit the invasion of LLC-MK2 (from monkey kidney) cells by 50-70%, and in T. brucei, aptamers with the potential to transport toxic molecules to the parasitic lysosome were identified as a novel therapeutic strategy.

Los aptámeros son secuencias de ADN o ARN de cadena sencilla que adoptan la forma de estructuras tridimensionales únicas, lo cual les permite reconocer un blanco específico con gran afinidad. Sus usos potenciales abarcan, entre otros, el diagnóstico de enfermedades, el desarrollo de nuevos agentes terapéuticos, la detección de riesgos alimentarios, la producción de biosensores, la detección de toxinas, el transporte de fármacos en el organismo y la señalización de nanopartículas. El pegaptanib es el único aptámero aprobado para uso comercial por la Food and Drug Administration (FDA).  En parasitología, se destacan los estudios que se vienen realizando en Leishmania spp., con la obtención de aptámeros que reconocen la proteína de unión a poliA (LiPABP) y que pueden tener potencial utilidad en la investigación, el diagnóstico y el tratamiento de la leishmaniasis. En cuanto a la malaria, se han obtenido aptámeros que permiten identificar eritrocitos infectados e inhiben la formación de rosetas, y otros que prometen ser alternativas para el diagnóstico al detectar de forma específica la proteína lactato deshidrogenasa (PfLDH). Para Cryptosporidium parvuum se han seleccionado aptámeros que detectan ooquistes a partir de alimentos o aguas contaminadas. Para Entamoeba histolytica se han aislado dos aptámeros llamados C4 y C5, que inhiben la proliferación in vitro de los trofozoítos y tienen potencial terapéutico. Los aptámeros contra Trypanosoma cruzi inhiben la invasión de células LLC-MK2 (de riñón de mono) en un 50 a 70 % y aquellos contra T. brucei transportan moléculas tóxicas al lisosoma parasitario como una novedosa estrategia terapéutica.

Nomogram to predict rectal toxicity following prostate cancer radiotherapy.

BACKGROUND: To identify predictors of acute and late rectal toxicity following prostate cancer radiotherapy (RT), while integrating the potential impact of RT technique, dose escalation, and moderate hypofractionation, thus enabling us to generate a nomogram for individual prediction. METHODS: In total, 972 patients underwent RT for localized prostate cancer, to a total dose of 70 Gy or 80 Gy, using two different fractionations (2 Gy or 2.5 Gy/day), by means of several RT techniques (3D conformal RT [3DCRT], intensity-modulated RT [IMRT], or image-guided RT [IGRT]). Multivariate analyses were performed to identify predictors of acute and late rectal toxicity. A nomogram was generated based on the logistic regression model used to predict the 3-year rectal toxicity risk, with its accuracy assessed by dividing the cohort into training and validation subgroups. RESULTS: Mean follow-up for the entire cohort was 62 months, ranging from 6 to 235. The rate of acute Grade ≥2 rectal toxicity was 22.2%, decreasing when combining IMRT and IGRT, compared to 3DCRT (RR = 0.4, 95%CI: 0.3-0.6, p<0.01). The 5-year Grade ≥2 risks for rectal bleeding, urgency/tenesmus, diarrhea, and fecal incontinence were 9.9%, 4.5%, 2.8%, and 0.4%, respectively. The 3-year Grade ≥2 risk for overall rectal toxicity increased with total dose (p<0.01, RR = 1.1, 95%CI: 1.0-1.1) and dose per fraction (2Gy vs. 2.5Gy) (p = 0.03, RR = 3.3, 95%CI: 1.1-10.0), and decreased when combining IMRT and IGRT (RR = 0.50, 95% CI: 0.3-0.8, p<0.01). Based on these three parameters, a nomogram was generated. CONCLUSIONS: Dose escalation and moderate hypofractionation increase late rectal toxicity. IMRT combined with IGRT markedly decreases acute and late rectal toxicity. Performing combined IMRT and IGRT can thus be envisaged for dose escalation and moderate hypofractionation. Our nomogram predicts the 3-year rectal toxicity risk by integrating total dose, fraction dose, and RT technique.

Detection of bladder metabolic artifacts in (18)F-FDG PET imaging.

Positron emission tomography using (18)F-fluorodeoxyglucose ((18)F-FDG-PET) is a widely used imaging modality in oncology. It enables significant functional information to be included in analyses of anatomical data provided by other image modalities. Although PET offers high sensitivity in detecting suspected malignant metabolism, (18)F-FDG uptake is not tumor-specific and can also be fixed in surrounding healthy tissue, which may consequently be mistaken as cancerous. PET analyses may be particularly hampered in pelvic-located cancers by the bladder׳s physiological uptake potentially obliterating the tumor uptake. In this paper, we propose a novel method for detecting (18)F-FDG bladder artifacts based on a multi-feature double-step classification approach. Using two manually defined seeds (tumor and bladder), the method consists of a semi-automated double-step clustering strategy that simultaneously takes into consideration standard uptake values (SUV) on PET, Hounsfield values on computed tomography (CT), and the distance to the seeds. This method was performed on 52 PET/CT images from patients treated for locally advanced cervical cancer. Manual delineations of the bladder on CT images were used in order to evaluate bladder uptake detection capability. Tumor preservation was evaluated using a manual segmentation of the tumor, with a threshold of 42% of the maximal uptake within the tumor. Robustness was assessed by randomly selecting different initial seeds. The classification averages were 0.94±0.09 for sensitivity, 0.98±0.01 specificity, and 0.98±0.01 accuracy. These results suggest that this method is able to detect most (18)F-FDG bladder metabolism artifacts while preserving tumor uptake, and could thus be used as a pre-processing step for further non-parasitized PET analyses.

Random forests to predict tumor recurrence following cervical cancer therapy using pre- and per-treatment 18F-FDG PET parameters.

The ability to predict tumor recurrence after chemoradiotherapy of locally advanced cervical cancer is a crucial clinical issue to intensify the treatment of the most high-risk patients. The objective of this study was to investigate tumor metabolism characteristics extracted from pre- and per-treatment 18F-FDG PET images to predict 3-year overall recurrence (OR). A total of 53 locally advanced cervical cancer patients underwent pre- and per-treatment 18F-FDG PET (respectively PET1 and PET2). Tumor metabolism was characterized through several delineations using different thresholds, based on a percentage of the maximum uptake, and applied by region-growing. The SUV distribution in PET1 and PET2 within each segmented region was characterized through 7 intensity and histogram-based parameters, 9 shape descriptors and 16 textural features for a total of 1026 parameters. Predictive capability of the extracted parameters was assessed using the area under the receiver operating curve (AUC) associated to univariate logistic regression models and random forest (RF) classifier. In univariate analyses, 36 parameters were highly significant predictors of 3-year OR (p<;0.01), AUC ranging from 0.72 to 0.83. With RF, the Out-of-Bag (OOB) error rate using the totality of the extracted parameters was 26.42% (AUC=0.72). By recursively eliminating the less important variables, OOB error rate of the RF classifier using the nine most important parameters was 13.21% (AUC=0.90). Results suggest that both pre- and per-treatment 18F-FDG PET exams provide meaningful information to predict the tumor recurrence. RF classifier is able to handle a very large number of extracted features and allows the combination of the most prognostic parameters to improve the prediction.

Los aptámeros como novedosa herramienta diagnóstica y terapéutica y su potencial uso en parasitología / Aptamers as a novel diagnostic and therapeutic tool and their potential use in parasitology

Los aptámeros son secuencias de ADN o ARN de cadena sencilla que adoptan la forma de estructuras tridimensionales únicas, lo cual les permite reconocer un blanco específico con gran afinidad. Sus usos potenciales abarcan, entre otros, el diagnóstico de enfermedades, el desarrollo de nuevos agentes terapéuticos, la detección de riesgos alimentarios, la producción de biosensores, la detección de toxinas, el transporte de fármacos en el organismo y la señalización de nanopartículas. El pegaptanib es el único aptámero aprobado para uso comercial por la Food and Drug Administration (FDA). Otros aptámeros para el tratamiento de enfermedades están en la fase clínica de desarrollo. En parasitología, se destacan los estudios que se vienen realizando en Leishmania spp., con la obtención de aptámeros que reconocen la proteína de unión a poliA (LiPABP) y que pueden tener potencial utilidad en la investigación, el diagnóstico y el tratamiento de la leishmaniasis. En cuanto a la malaria, se han obtenido aptámeros que permiten identificar eritrocitos infectados e inhiben la formación de rosetas, y otros que prometen ser alternativas para el diagnóstico al detectar de forma específica la proteína lactato deshidrogenasa (PfLDH). Para Cryptosporidium parvuum se han seleccionado aptámeros que detectan ooquistes a partir de alimentos o aguas contaminadas. Para Entamoeba histolytica se han aislado dos aptámeros llamados C4 y C5, que inhiben la proliferación in vitro de los trofozoítos y tienen potencial terapéutico. Los aptámeros contra Trypanosoma cruzi inhiben la invasión de células LLC-MK2 (de riñón de mono) en un 50 a 70 % y aquellos contra T. brucei transportan moléculas tóxicas al lisosoma parasitario como una novedosa estrategia terapéutica. Los datos recopilados en esta revisión destacan los aptámeros como una alternativa para la investigación, el diagnóstico y el tratamiento contra parásitos de interés nacional.

Aptamers are single-stranded DNA or RNA sequences that adopt unique three-dimensional structures that allow them to recognize a specific target with high affinity. They can potentially be used for the diagnosis of diseases, as new therapeutic agents, for the detection of food risks, as biosensors, for the detection of toxins, and as drug carriers and nanoparticle markers, among other applications. To date, an aptamer called pegaptanib is the only aptamer approved by the Food and Drug Administration (FDA) for commercial use. Other aptamers are in different clinical stages of development for the treatment of different diseases. In parasitology, investigations carried out with parasites such as Leishmania spp. allowed the acquisition of aptamers that recognize the polyA-binding protein LiPABP and may have potential applications in research and diagnosis and even as therapeutic agents. Regarding malaria, aptamers have been obtained that allow the identification of infected erythrocytes or inhibit the formation of rosettes, along with those that provide promising alternatives for diagnosis by specifically detecting the protein lactate dehydrogenase (PfLDH). In Cryptosporidium parvum allow the detection of oocysts in contaminated food or water. In Entamoeba histolytica, two aptamers called C4 and C5, which inhibit the proliferation of trophozoites in vitro and have potential use as therapeutic agents, have been isolated. Aptamers obtained against Trypanosoma cruzi inhibit the invasion of LLC-MK2 (from monkey kidney) cells by 50-70%, and in T. brucei, aptamers with the potential to transport toxic molecules to the parasitic lysosome were identified as a novel therapeutic strategy. The data collected in this review highlight aptamers as a novel alternative in the research, diagnosis, and treatment of parasites of national interest.

Weighted quantification of ¹8F-FDG tumor metabolism activity using fuzzy-thresholding to predict post-treatment tumor recurrence.

Cervical cancer is one of the most common cancer to affect women worldwide. Despite the efficiency of radiotherapy treatment, some patients present post-treatment tumor recurrence which increases the risk of death. Early outcome prediction could help oncologists to adapt the treatment. Several studies suggest that quantification of tumor activity using (18)FFDG PET imaging could be used to predict post-treatment tumor recurrence. In this paper we study the predictive value of weighted quantification of tumor metabolism extracted by fuzzy-thresholding for tumor recurrence of locally advanced cervical cancer. Fifty-three patients with locally advanced cervical cancer treated by chemo-radiotherapy were considered in our study. For each patient, a coregistered (18)F-FDG PET/CT scan was acquired before the treatment and was segmented using different hard and fuzzy segmentations methods. The tumor activity was extracted through the total lesion glycolysis and through a weighted analog of the total lesion glycolysis using the probability maps provided by the fuzzy segmentations. Outcomes prediction was performed using the area under the receiver operating characteristic curve (AUC) and the Harrell's C-index. Results suggest that weighted quantification of tumor activity seems to be strongly informative and could be used to predict post-treatment tumor recurrence in cervical cancer.

On feature extraction and classification in prostate cancer radiotherapy using tensor decompositions.

External beam radiotherapy is commonly prescribed for prostate cancer. Although new radiation techniques allow high doses to be delivered to the target, the surrounding healthy organs (rectum and bladder) may suffer from irradiation, which might produce undesirable side-effects. Hence, the understanding of the complex toxicity dose-volume effect relationships is crucial to adapt the treatment, thereby decreasing the risk of toxicity. In this paper, we introduce a novel method to classify patients at risk of presenting rectal bleeding based on a Deterministic Multi-way Analysis (DMA) of three-dimensional planned dose distributions across a population. After a non-rigid spatial alignment of the anatomies applied to the dose distributions, the proposed method seeks for two bases of vectors representing bleeding and non bleeding patients by using the Canonical Polyadic (CP) decomposition of two fourth order arrays of the planned doses. A patient is then classified according to its distance to the subspaces spanned by both bases. A total of 99 patients treated for prostate cancer were used to analyze and test the performance of the proposed approach, named CP-DMA, in a leave-one-out cross validation scheme. Results were compared with supervised (linear discriminant analysis, support vector machine, K-means, K-nearest neighbor) and unsupervised (recent principal component analysis-based algorithm, and multidimensional classification method) approaches based on the registered dose distribution. Moreover, CP-DMA was also compared with the Normal Tissue Complication Probability (NTCP) model. The CP-DMA method allowed rectal bleeding patients to be classified with good specificity and sensitivity values, outperforming the classical approaches.

Impact of head and neck cancer adaptive radiotherapy to spare the parotid glands and decrease the risk of xerostomia.

BACKGROUND: Large anatomical variations occur during the course of intensity-modulated radiation therapy (IMRT) for locally advanced head and neck cancer (LAHNC). The risks are therefore a parotid glands (PG) overdose and a xerostomia increase. The purposes of the study were to estimate: - the PG overdose and the xerostomia risk increase during a "standard" IMRT (IMRTstd); - the benefits of an adaptive IMRT (ART) with weekly replanning to spare the PGs and limit the risk of xerostomia. MATERIAL AND METHODS: Fifteen patients received radical IMRT (70 Gy) for LAHNC. Weekly CTs were used to estimate the dose distributions delivered during the treatment, corresponding either to the initial planning (IMRTstd) or to weekly replanning (ART). PGs dose were recalculated at the fraction, from the weekly CTs. PG cumulated doses were then estimated using deformable image registration. The following PG doses were compared: pre-treatment planned dose, per-treatment IMRTstd and ART. The corresponding estimated risks of xerostomia were also compared. Correlations between anatomical markers and dose differences were searched. RESULTS: Compared to the initial planning, a PG overdose was observed during IMRTstd for 59% of the PGs, with an average increase of 3.7 Gy (10.0 Gy maximum) for the mean dose, and of 8.2% (23.9% maximum) for the risk of xerostomia. Compared to the initial planning, weekly replanning reduced the PG mean dose for all the patients (p<0.05). In the overirradiated PG group, weekly replanning reduced the mean dose by 5.1 Gy (12.2 Gy maximum) and the absolute risk of xerostomia by 11% (p<0.01) (30% maximum). The PG overdose and the dosimetric benefit of replanning increased with the tumor shrinkage and the neck thickness reduction (p<0.001). CONCLUSION: During the course of LAHNC IMRT, around 60% of the PGs are overdosed of 4 Gy. Weekly replanning decreased the PG mean dose by 5 Gy, and therefore by 11% the xerostomia risk.

Panorama de resistencia antimicrobiana de los aislamientos urinarios de pacientes adultos en los servicios de urgencias de Manizales, Caldas, durante el 2018 / Overview of antimicrobial resistance in urinary tract isolates from adult patients in the emergency room service of Manizales, Caldas, in 2018

Introducción: los servicios de urgencias requieren de la toma de medidas eficaces y oportunas en el manejo de los pacientes, esto incluye el uso adecuado de antibióticos. La resistencia antimicrobiana dificulta la instauración de terapias empíricas adecuadas, por lo que su vigilancia toma un papel fundamental en los programas de optimización de uso de antimicrobianos. Objetivo: describir el perfil microbiológico y la resistencia antibiótica de los aislamientos urinarios obtenidos de pacientes adultos de los servicios de urgencias de 7 instituciones de tercer nivel de la ciudad de Manizales, durante el año 2018. Resultados: se recolectaron 1991 aislamientos urinarios, el microorganismo más frecuentemente aislado fue Escherichia coli con un 62%. Se encontraron altas tasas de resistencia a cefazolina, trimetoprim/sulfametoxazol, ciprofloxacina y ampicilina/sulbactam. La resistencia a nitrofurantoína y fosfomicina al igual que a carbapenémicos es baja para Escherichia coli. Los aislamientos urinarios de Pseudomonas aeruginosa muestran niveles de resistencia superiores al promedio nacional. Conclusiones: es importante individualizar el manejo antibiótico empírico, teniendo en cuenta la estratificación por severidad, la presencia de factores de riesgo para bacterias multidrogorresistentes, y la epidemiología local; los análisis de cada institución y los resultados de este trabajo, pueden ser utilizados para establecer conductas terapéuticas más precisas en los casos de infecciones del tracto urinario, mejorando los desenlaces de estos pacientes y los costos derivados de la atención en salud.

Introduction: patient management in emergency rooms require swift and effective clinical decisions; this includes choosing antibiotics correctly. Antimicrobial resistance impairs the adequate choice of empirical therapy, making the surveillance of utmost importance for antimicrobial stewardship programs. Objective: we aimed to describe the microbiological and antimicrobial resistance profile of urinary isolates obtained from adult patients of the emergency services of seven tertiary institutions in the city of Manizales, during the year 2018. Results: from a total of 1991 urinary tract isolates, 62% corresponded to Escherichia coli, the most common bacteria cultured from the emergency room. Susceptibility analysis revealed high resistance levels to cefazolin, trimethoprim-sulfamethoxazole, and ciprofloxacin. Resistance to nitrofurantoin, fosfomycin, and carbapenems was low for Escherichia coli isolates. Pseudomonas aeruginosa showed antimicrobial resistance levels above national averages. Conclusions: empirical antibiotic therapy must be tailored on a patient by patient basis, taking into account the severity of the disease, risk factors for multi-drug resistance bacteria, the institutional and local epidemiology depicted in this work. By using these results, the adjustment of empirical antimicrobial regimens for urinary tract infections could improve clinical outcomes and reduce health care costs.

A tensor-based population value decomposition to explain rectal toxicity after prostate cancer radiotherapy.

In prostate cancer radiotherapy the association between the dose distribution and the occurrence of undesirable side-effects is yet to be revealed. In this work a method to perform population analysis by comparing the dose distributions is proposed. The method is a tensor-based approach that generalises an existing method for 2D images and allows for the highlighting of over irradiated zones correlated with rectal bleeding after prostate cancer radiotherapy. Thus, the aim is to contribute to the elucidation of the dose patterns correlated with rectal toxicity. The method was applied to a cohort of 63 patients and it was able to build up a dose pattern characterizing the difference between patients presenting rectal bleeding after prostate cancer radiotherapy and those who did not.

Mestizo anterior teeth's proportions / Proporciones de los dientes anteriores en una población mestiza

Teeth proportions relate to beauty and harmony but aesthetic dental ideal proportion models show inconsistent results. Golden Proportion´s, Preston's, Fayyad's, Snow's, and Ward's models where characterized for best fit in a Colombian mestizo population anterior teeth. Models of teeth´s beauty proportions (Golden Proportion´s, Preston's, Fayyad's, Snow's, and Ward') are analyzed for best fit in a mestizo (mixed race) Colombian population and variables as sex, aesthetic balance or history of previous orthodontic treatments were also analyzed for their probable impact on the distribution of the dental proportions. It was used standardized photographs of anterior teeth on 351 individuals of both sexes with complete erupted and healthy teeth. The measurements were done by calibrated computer software (error of 0.05 mm). A Chi squared test was used to check whether sex, aesthetic balance and previous orthodontic treatment had an impact on the distribution of the dental proportions. Also a nonparametric Wilcoxon test was used to analysis the null hypothesis. A cluster analysis using k means was carried out to search for subgroups, which better explain the distribution of anterior dental proportions in the sample. For the considered results the null hypothesis of the mean equaling to the Golden Proportion was rejected (Wilcoxon test p value <0.001). For the whole population, the Chi squared test did not reject the null hypothesis of equal proportions among the groups with respect to the sex (p value= 0.56), aesthetic balance (p value= 0.98) and history of previous orthodontic treatments (p value= 0.67) variables. For the aesthetically balanced individuals, the Chi squared test also failed to reject the null hypothesis of equal proportions among the groups with respect to the sex (p value= 0.63) and history of previous orthodontic treatments (p value= 0.93) variables. Two Gaussian distributions were found for RED models fitting well in 58 % for RED 70 % (0.7 SD 0.03) and 42 % for RED 75 (0.75 SD 0.025). From the cluster analysis using k means, two groups were identified in the whole sample. No universal model can describe the whole population but is possible to find a set of models for the different population subgroups. Aesthetically ideals are open to interpretation. Clinical aesthetically standards for ideal teeth proportions are open to interpretation in a mestizo (mixed raced) population.

Las proporciones de los dientes se refieren a su belleza y armonía, pero los modelos de proporciones dentales estéticas ideales muestran resultados inconsistentes. La proporción Aurea y los modelos de Preston, Fayyad, Snow, y Ward fueron ajustados para caracterizar los dientes de una población colombiana mestiza. Modelos de proporciones de belleza de dientes (Proporción Aurea, Modelos de Preston, Fayyad, Snow y Ward) se analizaron para lograr alcanzar el mejor ajuste en una población colombiana mestiza (mezcla de razas), y también se analizaron las variables de sexo, equilibrio estético e historia de tratamientos de ortodoncia previos para evaluar su probable impacto sobre la distribución de las proporciones dentales consideradas. Fueron utilizadas fotografías estandarizadas de dientes anteriores de 351 individuos de ambos sexos con dientes completamente erupcionados y sanos. Las mediciones fueron realizadas con programas informáticos calibrados (error de 0,05 mm). Se utilizó la prueba Chi Cuadrado para comprobar si el sexo, el equilibrio estético y el tratamiento ortodóncico previo tuvieron un impacto en la distribución de las proporciones dentales. También se utilizó la prueba no paramétrica de Wilcoxon para el análisis de la hipótesis nula. Un análisis de conglomerados, utilizando la media k, se llevó a cabo para buscar subgrupos, que explicaron mejor la distribución de proporciones dentales anteriores en la muestra. Para que los resultados fueran considerados, la hipótesis nula de la media que equivale a la proporción áurea fue rechazada (Prueba de Wilcoxon, valor p <0,001). Para toda la población, la prueba de Chi Cuadrado no rechazó la hipótesis nula de proporciones iguales entre los grupos con respecto al sexo (valor de p= 0,56), equilibrio estético (valor de p= 0,98) y la historia de tratamientos de ortodoncia previos ( valor de p= 0,67). Para los individuos estéticamente balanceados, la prueba de Chi Cuadrado tampocó rechazó la hipótesis nula de proporciones iguales entre los grupos con respecto a las variables de sexo (valor p= 0,63) y la historia de los tratamientos de ortodoncia anteriores (valor p= 0,93). Se encontraron dos distribuciones gaussianas para los modelos RED que encajaron bien en el 58% para RED 70 % (0,7 DE 0,03) y el 42 % para RED 75 (0,75 DE 0,025). Con respecto al análisis de los conglomerados a través de las medias k, se identificaron dos grupos en toda la muestra. No hay un modelo universal que pueda describir toda la población, pero es posible encontrar un conjunto de modelos para los diferentes subgrupos de población. Los ideales estéticamente están abiertos a interpretación. Las normas clínicas de estética para dientes con proporciones ideales están abiertos a interpretación en una población mestiza.

Frecuencia de Diabetes Mellitus Gestacional y factores de riesgo en gestantes atendidas en clínicas de ASSBASALUD ESE, Manizales (Colombia) 2011-2012: estudio de corte transversal / Frequency of gestational diabetes mellitus and risk factors in pregnant women treated at ASSBASALUD ESE clinics in Manizales (Colombia), in 2011-2012: cross-sectional study

Objetivo: establecer la frecuencia de diabetes mellitus gestacional (DMG) y explorar posibles factores de riesgo para su desarrollo en un grupo de gestantes atendidas en primer nivel de atención. Materiales y métodos: estudio de corte transversal analítico en gestantes atendidas en ASSBASALUD ESE, institución privada de primer nivel de atención en salud ubicada en Manizales (Colombia) en los años 2011-2012. No se incluyeron pacien tes con diabetes mellitus diagnosticada previa al embarazo. Muestreo consecutivo. Se evaluaron las variables demográficas y antropométricas de los recién nacidos, la vía del parto, el diagnóstico de laboratorio de DMG y el resultado de la prueba de O'Sullivan. Se describe la prevalencia de periodo y se hace comparación entre el grupo que presentó DMG y el que no la presentó, mediante la prueba Chi 2 y la prueba t. Resultados: se incluyeron 1.138 mujeres. Se encontró 6,3 % de prevalencia de DMG, y una prevalencia de 10,7 % de prueba de O'Sullivan positiva. La mayor prevalencia de DMG se encontró en mujeres con formación universitaria (15,2 %), con una edad comprendida entre los 40 y 50 años (21,4 %), con dos o más gravideces (7,6 %). De las pacientes del estudio que presentaron sobrepeso, el 8,3 % desarrolló DMG. El peso de los bebés de gestantes con DMG fue de 3.263 g promedio. El 6,5 % de las gestantes con excesivo aumento de peso presentó DMG, comparado con el 3,8 % presentado por las gestantes con aumento de peso normal. No se encontró relación entre el desarrollo de DMG y la no asistencia al curso psicoprofiláctico. Conclusiones: La proporción de DMG en gestantes encontrada en la presente investigación, está dentro de los límites hallados en población mundial. La edad de la gestante, sus partos previos y el nivel educativo mostraron asociación con el desarrollo de DM.

Objective: To determine the frequency of gestational diabetes mellitus (GDM) and explore potential risk factors in pregnant women seen in primary care. Materials and methods: Analytical cross-sectional study in pregnant women seen at ASSBASALUD ESE, a private, level-one healthcare institution in Manizales (Colombia), in 2011- 2012. Patients diagnosed with diabetes mellitus before pregnancy were not included. Consecutive sampling. Demographics and anthropometric variables of the neonates, route of deliver y, laboratory diagnosis of GDM and the result of the O'Sullivan test were assessed. Period prevalence is described and a comparison is made between the group presenting GDM and the group that did not, using the Chi square and t tests. Results: Overall, 1,138 women were included. The prevalence of GDM was found to be 6.3 % and the prevalence of a positive O'Sullivan test was found to be 10.7%. The highest prevalence of GDM was found among women with college education (15.2%), between the ages of 40-50 (21.4%), with two or more pregnancies (7.6 %). Of the patients in the study who were overweight, 8.3% developed GDM. Babies born to mothers with GDM had a mean weight at birth of 3,263 g. Among pregnant women with excess weight gain, 6.5 % developed GDM, compared to 3.8 % in women with normal weight gain. No relationship was found between the development of GDM and non-attendance to psychoprophylactic preparation. Conclusions: The proportion of GDM in the study population was comparable to that found in other populations. No risk factors were found in the study population.

Biooxidación de concentrados de arsenopirita por Acidithiobacillus ferrooxidans en erlenmeyer agitados / Biooxidation of arsenopyrite concentrates by Acidithiobacillus ferrooxidans in shake flasks

Se evaluó el proceso de biooxidación de concentrados de arsenopirita por A. ferrooxidans ATCC 23270, previa adaptación de los microorganismos al mineral y dos tamaños de partícula, pasante malla Tyler 200 (~75μm) y 325 (~45μm). También, se determinó el grado de concentración del mineral mediante DRX y MOLPP/LR, bajo norma ASTM D 2799 de 2009. Los microorganismos fueron adaptados mediante disminución gradual, en etapas sucesivas, de sulfato ferroso y posterior aumento en el contenido de arsenopirita. Finalmente, se llevó a cabo el proceso de biooxidación del mineral sin adición de Fe2+. Después de treinta días de proceso, la disolución de arsénico para la malla Tyler 200 fue de 7550 mgL-1 (18,7%) y para la malla Tyler 325 fue de 2850 mgL-1 (7,1%). Por otra parte, la curva de crecimiento bacteriano mostró que entre los días 6 y 21 de proceso la población bacteriana promedio fue de 1,70x108 cel.mL-1 y de 8,00x107 cel.mL-1 para las mallas Tyler 200 y 325, respectivamente.Por lo tanto, el tamaño de partícula jugó un papel fundamental en la cinética de adaptación de los microorganismos, sugiriendo que a menor tamaño del sustrato empleado mayor dificultad se le presenta al microorganismo para oxidar el mineral.

Arsenopyrite biooxidation process was evaluated with A. ferrooxidans ATCC 23270. The microorganisms were previously adapted to mineral and two different Tyler mesh sizes, 200 (~75μm) and 325 (~45μm). Also, the mineral concentration was made by DRX and MOLPP/LR under ASTM D 2799. The microorganisms were adapted through gradual decreasing of ferrous sulphate in successive state and subsequent arsenopyrite concentration increase. Finally, biooxidation process was carried out without Fe2+. After thirty days of process, Arsenic bioleaching was 7550 mgL-1(18,7%) and 2850 mgL-1 (7,1%) for the 200 and 325 Tyler meshes, respectively.On the other hand, bacterial growth curve showed, between 6 and 21 days of process that the average bacterial population was 1,70x108 cel.mL-1 y de 8,00x107 cel.mL-1 for 200 and 325 Tyler mesh respectively. For this reason, the particle size played an important role in the adaption kinetics of microorganism. The results showed that the microorganism oxide the larger particle size of the mineral easier.