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OBJECTIVE: The objective is to describe the HLA allelic frequency in PsA and correlate it with demographic and clinical variables. METHODS: Retrospective study of adult patients with a diagnosis of PsA (n=23) and healthy controls (n=46), all with a request for HLA-A, B, C, DR. Typing was performed using HLA-PCR/SSO LifeCodes and analyzed on the LUMINEX IS100/200 xMAP® system. (Ethics/Code HMC2022-014). RESULTS: One hundred thirty-eight alleles were included from 69 individuals, 43,5% women, aged 44,5±16,5 years in patients with PsA, with a mean age of disease onset of 33.4±14 years. Only 9.5% had a high Body Mass Index and dyslipidemia was the most frequent comorbidity (34.8%), followed by high blood pressure (26,1%). 82% debuted with skin manifestation and once the joint disease was established, the predominance was peripheral (74%) due to arthritis/arthralgia in 74%, enthesitis in 30% and dactylitis in 13%. The allele frequencies were for HLA*A 2402 (13%), 3201 (13%) and 2427 (8,7%), for HLA*B 1402 (17,4%), 4002 (17,4%), 3801 (13%) and HLA*DR 0404 (17,4%), 0407 (13%). No HLA*B27 was identified and HLA*C0602 was only 2,2%. HLA A*0201 and DR*1301 were less frequent in controls versus PsA (p=0.024 and 0,029, respectively), while HLA*B1302 was frequent in PsA (p=0,035). CONCLUSIONS: Curiously, there were no positive results for HLAB*27, which may be related to the population mix. HLA Cw6 is traditionally associated with psoriasis. However, its absence has been linked to nail disorders and PsA; consequently, in our study, it had a low frequency (2,2%). On the other hand, HLA*B1302 has been related to the disease and its early onset; in the healthy Colombian population, it has been described in 0,92%; in our group, it is found to be significant in patients without establishing a clinical association. Few previous studies report HLA results in PsA in Colombia.
OBJETIVO: Describir la frecuencia alélica de HLA en APs y asociarlo con variables demográficas y clínicas. MÉTODOS: Estudio retrospectivo de pacientes adultos con diagnóstico de APs (n=23), y controles sanos (n=46), todos con solicitud de HLA-A, B, C y DR. La tipificación se realizó por medio de HLA-PCR/SSO LifeCodes, y se analizó en el sistema LUMINEX IS 100/200 xMAP®. (Ética/Código HMC2022-014). RESULTADOS: Se incluyeron 138 alelos de 69 individuos, 43,5% mujeres, con edad 44,5±16,5 años, en pacientes con APs, con edad media de inicio de la enfermedad de 33,4±14 años. Solo el 9,5% tuvo Índice de Masa Corporal alto y la dislipidemia fue la comorbilidad más frecuente (34,8%), seguida de hipertensión arterial (26,1%). El 82% debutó con manifestación en piel y una vez establecida la enfermedad articular, el predominio fue periférico (74%), por artritis/artralgias en un 74%, entesitis en 30%, y dactilitis 13%. Las frecuencias alélicas fueron para HLA*A 2402 (13%), 3201 (13%) y 2427 (8,7%), para HLA*B 1402 (17,4%), 4002 (17,4%), 3801 (13%) y HLA*DR 0404 (17,4%), 0407 (13%). No se identificó HLA*B27 y HLA*C0602 fue solo del 2,2 %. HLA A*0201 y DR*1301 fueron menos frecuentes en controles versus APs (p=0,024 y 0,029, respectivamente), mientras que HLA*B1302 frecuente en APs (p=0,035). CONCLUSIÓN: Curiosamente no hubo resultados positivos para HLAB*27 y esto puede relacionarse con el mestizaje de la población. HLA Cw6 es tradicionalmente asociado a psoriasis, sin embargo, su ausencia se ha relacionado con mayor reporte de alteraciones ungueales y Aps; como consecuencia, en nuestro estudio tuvo una baja frecuencia (2,2%). Por otro lado, el HLA*B1302 ha tenido relación con la enfermedad y su inicio temprano, en población sana colombiana se ha descrito en 0,92%, en nuestro grupo se encuentra de manera significativa en los pacientes sin establecerse asociación clínica. Pocos estudios previos refieren resultados de HLA en APs en Colombia.
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Alelos , Artritis Psoriásica , Frecuencia de los Genes , Humanos , Femenino , Masculino , Colombia , Adulto , Artritis Psoriásica/genética , Artritis Psoriásica/diagnóstico , Estudios Retrospectivos , Persona de Mediana Edad , Antígenos HLA/genéticaRESUMEN
INTRODUCTION: Surgery for cardiac trauma is considered fatal and for wounds of the colon by associated sepsis is normally considered; however, conservative management of many traumatic lesions of different injured organs has progressed over the years. PRESENTATION OF THE CASE: A 65-year-old male patient presented with multiple shotgun wounds on the left upper limb, thorax, and abdomen. On evaluation, he was hemodynamically stable with normal sinus rhythm and normal blood pressure, no dyspnea, or abdominal pain. Computed tomography (CT) scan of the chest shows hematoma around the aorta without injury to the blood vessel wall with an intramyocardial projectile without pericardial effusion. CT scan of the abdomen showed pellets in the transverse colon and descending colon endoluminal without extravasation of contrast medium or intra-abdominal fluid. The patient remains hemodynamically stable, and nonsurgical procedure was established. DISCUSSION: Patients with asymptomatic intramyocardial projectiles can be safely managed without surgery. Nonsurgical management is only possible in asymptomatic patients with trauma of the colon through close surveillance and with very selective patients since standard management is surgery. CONCLUSION: Nonsurgical management of cardiac trauma, as well as colon penetrating trauma, can be performed in carefully selected patients with proper clinical follow-up, imaging, and laboratory studies.
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Hemicorporectomy is an ultra-radical surgery used only in extreme circumstances. Initially used for advanced pelvic neoplastic diseases and intractable pelvic infection, it may also be the only treatment option in patients with crushed pelvic trauma, in cases there are no reconstruction options. This procedure has a high mortality, and its success depends on the multidisciplinary approach, both in the initial phase and in the rehabilitation process. We present the case of a young patient with severe pelvic trauma that required a hemicorporectomy as the only treatment option and review of the literature.
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Amputación Quirúrgica/métodos , Lesiones por Aplastamiento/cirugía , Fracturas Óseas/cirugía , Huesos Pélvicos/lesiones , Adulto , Tratamiento de Urgencia , Humanos , MasculinoRESUMEN
ABSTRACT. A schwannoma is a slow-growing benign neoplasm of the peripheral nerves composed of Schwann cells. Pathologically, is characterized by solid, subcutaneous, asymptomatic lesions. Histologically, it is made of prototypes of cellular organization called Antoni A and Antoni B. The most common site for its occurrence is the tongue, followed by the palate, the floor of the mouth, the buccal mucosa, the lips, and the mandible. This article describes the case of a 55-year-old woman presenting with a firm, nodular, encapsulated mass in the sub mucous area of the vestibular zone behind the right cheek. The clinical, pathological, and immunohistochemical analysis showed that this was a case of intraoral schwannoma.
RESUMEN. El schwannoma es una neoplasia benigna de crecimiento lento de los nervios periféricos compuestos por células de Schwann. Su anatomía patológica se caracteriza por lesiones sólidas, subcutáneas y asintomáticas. Histológicamente está compuesto por prototipos de organización celular denominados Antoni A y Antoni B. La lengua es el sitio más común, seguido por paladar, piso de boca, mucosa bucal, labios y mandíbula. En este trabajo se describe un caso de una mujer de 55 años que presenta una masa firme, nodular y encapsulada en la zona submucosa del vestíbulo derecho detrás del carrillo. Después del análisis clínico, patológico e inmunohistoquímico, se determinó que era un caso de schwannoma intraoral.
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Inmunohistoquímica , Técnicas de Investigación , Carcinoma NeuroendocrinoRESUMEN
Recovery of arsenic contaminated areas is a challenge society faces throughout the world. Revegetation associated with microbial activity can play an essential role in this process. This work investigated biological attributes in a gold mining area with different arsenic contents at different sites under two types of extant revegetation associated with cover layers of the soil: BS, Brachiaria sp. and Stizolobium sp., and LEGS, Acacia crassicarpa, A. holosericea, A. mangium, Sesbania virgata, Albizia lebbeck and Pseudosamanea guachapele. References were also evaluated, comprising the following three sites: B1, weathered sulfide substrate without revegetation; BM, barren material after gold extraction and PRNH (private reserve of natural heritage), an uncontaminated forest site near the mining area. The organic and microbial biomass carbon contents and substrate-induced respiration rates for these sites from highest to lowest were: PRNH > LEGS > BS > B1 and BM. These attributes were negatively correlated with soluble and total arsenic concentration in the soil. The sites that have undergone revegetation (LEGS and BS) had higher densities of bacteria, fungi, phosphate solubilizers and ammonium oxidizers than the sites without vegetation. Principal component analysis showed that the LEGS site grouped with PRNH, indicating that the use of leguminous species associated with an uncontaminated soil cover layer contributed to the improvement of the biological attributes. With the exception of acid phosphatase, all the biological attributes were indicators of soil recovery, particularly the following: microbial carbon, substrate-induced respiration, density of culturable bacteria, fungi and actinobacteria, phosphate solubilizers and metabolic quotient.
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Arsénico/toxicidad , Microbiología del Suelo , Contaminantes del Suelo/toxicidad , Suelo/química , Biodegradación Ambiental , Biomasa , Brasil , Monitoreo del Ambiente , Minería , Fotometría , Espectrofotometría AtómicaRESUMEN
Cowpea is a legume of great agronomic importance that establishes symbiotic relationships with nitrogen-fixing bacteria. However, little is known about the genetic and symbiotic diversity of these bacteria in distinct ecosystems. Our study evaluated the genetic diversity and symbiotic efficiencies of 119 bacterial strains isolated from agriculture soils in the western Amazon using cowpea as a trap plant. These strains were clustered into 11 cultural groups according to growth rate and pH. The 57 nonnodulating strains were predominantly fast growing and acidifying, indicating a high incidence of endophytic strains in the nodules. The other 62 strains, authenticated as nodulating bacteria, exhibited various symbiotic efficiencies, with 68% of strains promoting a significant increase in shoot dry matter of cowpea compared with the control with no inoculation and low levels of mineral nitrogen. Fifty genotypes with 70% similarity and 21 genotypes with 30% similarity were obtained through repetitive DNA sequence (BOX element)-based PCR (BOX-PCR) clustering. The 16S rRNA gene sequencing of strains representative of BOX-PCR clusters showed a predominance of bacteria from the genus Bradyrhizobium but with high species diversity. Rhizobium, Burkholderia, and Achromobacter species were also identified. These results support observations of cowpea promiscuity and demonstrate the high symbiotic and genetic diversity of rhizobia species in areas under cultivation in the western Amazon.
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Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biodiversidad , Variación Genética , Fijación del Nitrógeno , Microbiología del Suelo , Bacterias/genética , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Fabaceae/microbiología , Fabaceae/fisiología , Datos de Secuencia Molecular , Tipificación Molecular , Filogenia , ARN Ribosómico 16S/genética , Nódulos de las Raíces de las Plantas/microbiología , Análisis de Secuencia de ADNRESUMEN
Agaricus brasiliensis CS1, Pleurotus ostreatus H1 and Aspergillus flavus produced holocellulases when grown in solid and submerged liquid cultures containing agro-industrial residues, including sugar cane bagasse and dirty cotton residue, as substrates. These isolates proved to be efficient producers of holocellulases under the conditions used in this screening. Bromatological analysis of agro-industrial residues showed differences in protein, fiber, hemicellulose, cellulose and lignin content. Maximal holocellulase activity (hemicellulase, cellulase and pectinase) was obtained using solid-state cultivation with 10% substrate concentration. In this case, remarkably high levels of xylanase and polygalacturonase activity (4,008 and 4,548 IU/l, respectively) were produced by A. flavus when grown in media containing corn residue, followed by P. ostreatus H1 with IU/l values of 1,900 and 3,965 when cultivated on 5% and 10% sugar cane bagasse, respectively. A. brasiliensis CS1 showed the highest reducing sugar yield (11.640 mg/ml) when grown on medium containing sugar cane bagasse. A. brasiliensis was also the most efficient producer of protein, except when cultivated on dirty cotton residue, which induced maximal production in A. flavus. Comparison of enzymatic hydrolysis of sugar cane bagasse and dirty cotton residue by crude extracts of A. brasiliensis CS1, P. ostreatus H1 and A. flavus showed that the best reducing sugar yield was achieved using sugar cane bagasse as a substrate.
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Agricultura , Celulasa/biosíntesis , Hongos/enzimología , Hongos/crecimiento & desarrollo , Residuos Industriales , Plantas/microbiología , Agaricus/enzimología , Agaricus/crecimiento & desarrollo , Aspergillus flavus/enzimología , Aspergillus flavus/crecimiento & desarrollo , Carbohidratos/análisis , Celulasa/metabolismo , Mezclas Complejas , Endo-1,4-beta Xilanasas/metabolismo , Proteínas Fúngicas/análisis , Hidrólisis , Oxidación-Reducción , Pleurotus/enzimología , Pleurotus/crecimiento & desarrolloRESUMEN
Objetivo. Hacer un análisis de la experiencia recolectada por la Unidad de Cirugía Hepatobiliar y Pancreática del Hospital Pablo Tobón Uribe, de los pacientes con cáncer de vesícula y observar la evolución con el manejo brindado.Pacientes y métodos. Se evaluaron todos los pacientes con carcinoma de vesícula que ingresaron por la Unidad de Cirugía Hepatobiliar y Pancreática entre el 1º de enero de 2004 y el 30 de junio del 2008. Se determinó el método diagnóstico, el estadio de la enfermedad, el tipo de manejo quirúrgico y sus resultados medidos en estancia hospitalaria y mortalidad relacionada, además de la evolución en el tiempo del tratamiento realizado.Resultados. Se recolectaron 40 pacientes con carcinoma de vesícula, 55% mujeres y 45% hombres, con edad promedio de 60,4 años. El diagnóstico se hizo antes de la cirugía en 62,5% de los casos y, por hallazgo incidental luego de colecistectomía en 37,5%. El estudio de imagen más utilizado fue la TAC, tanto para diagnóstico (28%) como para estadificación (53,3%).La estadificación tumoral al momento de la presentación fue estadio IV en el 72,5%, seguido por IB en el 12,5%. Sólo el 22,5% de los pacientes fue susceptible de cirugía con intención curativa; de éstos, 77,8% tuvo diagnóstico después de la colecistectomía inicial.El procedimiento quirúrgico más frecuentemente utilizado fue la hepatectomía central (segmentos IVB/V) más vaciamiento ganglionar del primer nivel. Para estos pacientes, la estancia hospitalaria fue, en promedio, de 7,8 días, con estancia en la unidad de cuidados intensivos de 0,7 días. No se presentó mortalidad relacionada con el procedimiento. La supervivencia promedio general fue de 6,7 meses, con un porcentaje de supervivencia de 27,5% a un año.Conclusión. El carcinoma de vesícula continúa teniendo un mal pronóstico, a pesar de la mejoría en las técnicas de imagen y al manejo quirúrgico radical, debido a que en la mayor parte de los casos en el momento del diagnóstico hay enfermedad avanzada. Sin embargo, éste es el único potencialmente curable.
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Humanos , Evolución Clínica , Diagnóstico , Neoplasias de la Vesícula Biliar , Hepatectomía , Mortalidad , PrevalenciaRESUMEN
Pterins are members of a family of heterocyclic compounds present in a wide variety of biological systems and may exist in two forms, corresponding to an acid and a basic tautomer. In this work, the proton transfer reaction between these tautomeric forms was investigated in the gas phase and in aqueous solution. In gas phase, the intramolecular mechanism was carried out for the isolated pterin by quantum mechanical second-order Møller-Plesset perturbation theory (MP2/aug-cc-pVDZ) calculations and it indicates that the acid form is more stable than the basic form by -1.4 kcal/mol with a barrier of 34.2 kcal/mol with respect to the basic form. In aqueous solution, the role of the water molecules in the proton transfer reaction was analyzed in two separated parts, the direct participation of one water molecule in the reaction path, called water-assisted mechanism, and the complementary participation of the aqueous solvation. The water-assisted mechanism was carried out for one pterin-water cluster by quantum mechanical calculations and it indicates that the acid form is still more stable by -3.3 kcal/mol with a drastic reduction of 70% of the barrier. The bulk solution effect on the intramolecular and water-assisted mechanisms was included by free energy perturbation implemented on Monte Carlo simulations. The bulk water effect is found to be substantial and decisive when the reaction path involves the water-assisted mechanism. In this case, the free energy barrier is only 6.7 kcal/mol and the calculated relative Gibbs free energy for the two tautomers is -11.2 kcal/mol. This value is used to calculate the pK(a) value of 8.2 +/- 0.6 that is in excellent agreement with the experimental result of 7.9.
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Protones , Pterinas/química , Agua/química , Simulación por Computador , Gases/química , Modelos Químicos , Método de Montecarlo , Teoría Cuántica , Solventes/químicaRESUMEN
The second-order response of the electron density with respect to changes in electron number, known as the dual descriptor, has been established as a key reactivity indicator for reactions like pericyclic reactions, where reagents accept and donate electrons concurrently. Here we establish that the dual descriptor is also the key reactivity indicator for ambiphilic reagents: reagents that can act either as electrophiles or as nucleophiles, depending on the reaction partner. Specifically, we study dual atoms (which are proposed to act, simultaneously, as an electron acceptor and an electron donor), dual molecules (which react with both electrophiles and nucleophiles, generally at different sites), and dual ion-molecule complexes (which react with both cations and anions). On the basis of our analysis, the dual atom (an Al(I) that has been purported to be dual in the literature) is actually pseudodual in the sense that it does not truly accept electrons from a nucleophiles; rather, it serves as a conduit through which an electrophile can donate electrons to the attached aromatic ring. For understanding dual ion-molecule complexes, it helps to understand that the dual descriptor makes a key contribution to the long-range portion of the quadratic hyperpolarization. In all cases, a complete description of the reactivity of the ambiphilic reagent requires considering both an orbital-based descriptor of electron transfer (the dual descriptor or the local hypersoftness) and the electrostatic potential. The local hypersoftness strongly resembles the dual descriptor.
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En Colombia existen diversas poblaciones en zonas aisladas que no tienen acceso a servicios de salud especializados, entre ellos salud mental. La telemedicina es una herramienta que permite proporcionar estos servicios, llevando medicina especializada a un menor costo y similar calidad a través de tecnologías de la información y las comunicaciones. Como una solución a esta problemática se propuso la estructuración de un protocolo de teleconsulta psiquiátrica y la implementación de una aplicación web, con el fin de proveer servicios de diagnóstico y control a pacientes con incidencia de enfermedades mentales. Para la realización de este proyecto se analizaron lineamientos clínicos y operacionales en servicios de telepsiquiatría, se realizó un análisis de algunas patologías de interés, se hizo un desarrollo del proceso de ingeniería de software, y por último se diseñó una evaluación técnica y clínica de la aplicación para así obtener una retroalimentación del sistema.
Colombia had are several isolated populations in areas without access to specialized health services, much less on mental health. Telemedicine is a tool that allows to provide these services, bringing specialized medicine at lower costs and similar quality through information and communication technologies. As a solution to this problem, a psychiatric tele-consultation protocol and the implementation of a web application was proposed in order to provide diagnosis and follow up to patients with mental diseases. For the development of this project; clinical and operational guidelines in Telepsychiatry services were reviewed, diseases of interest were analyzed, a software engineering process was implemented, and finally a clinical and technical evaluation were designed in order to have a feedback for the system.
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Introducción. El hepatocarcinoma es una neoplasia que, generalmente, se presenta en pacientes cirróticos y su manejo depende tanto del estado de la cirrosis como del tumor. Su incidencia se está incrementando a nivel mundial. El trasplante hepático es considerado por muchos la mejor alternativa para el manejo curativo en quienes cumplan los criterios de inclusión para dicho procedimiento.Materiales y métodos. Entre abril de 2004 y abril de 2008, se recolectaron de manera prospectiva todos los pacientes sometidos a trasplante hepático en el Hospital Pablo Tobón Uribe (Unidad de Trasplante Hepático Universidad de Antioquia-Hospital Pablo Tobón Uribe) de Medellín y se analizaron los resultados de las imágenes y de anatomopatología, de quienes se incluyeron en la lista de trasplantes con diagnóstico de hepatocarcinoma y de quienes en éste fue un hallazgo incidental.Resultados. De 153 trasplantes de hígado durante este período, 25 se hicieron con diagnóstico previo de hepatocarcinoma y en 3 fue un hallazgo incidental. Se incluyeron 21 hombres y 7 mujeres. La etiología de la cirrosis fue por hepatitis por virus B en 28,6% y hepatitis por virus C en 17,9%, seguidas por alcoholismo, enfermedad autoinmune y otras. Hubo 7 pacientes sin hallazgo de hepatocarcinoma en el hígado extraído del receptor, todos con imágenes previas que mostraban una lesión única diagnosticada como hepatocarcinoma; ninguno era Child A, por lo tanto, en todos la indicación de trasplante era una complicación de la cirrosis y no del tumor. La concordancia de las imágenes con la anatomopatología del hígado resecado fue mucho mejor para la resonancia magnética que para la tomografía computadorizada, 53,8% versus 38,8%.Discusión. El trasplante hepático es el tratamiento ideal para los pacientes con hepatocarcinoma y cirrosis. Es claro que esta terapia está restringida actualmente a pacientes con estadios tempranos del tumor, según los criterios de Milán. A pesar de los refinamientos en las técnicas de imágenes, todavía es frecuente encontrar discrepancias entre los hallazgos imaginológicos preoperatorios y los resultados definitivos de la anatomopatología en el hígado extraído del receptor, pero este hecho no es indicación para hacer, por el momento, ningún tipo de modificación en el manejo de estos pacientes, en vista de los buenos resultados encontrados en la supervivencia a 5 años.
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Humanos , Carcinoma , Carcinoma Hepatocelular , Neoplasias Hepáticas , Trasplante de Hígado , Imagen por Resonancia Magnética , Tomografía Computarizada por Rayos XRESUMEN
Boron compounds are widely used in synthetic chemistry. The synthesis of the compounds is relatively easy, presenting thermodynamic stability and synthetic versatility. Almost all of them show electrophilic reactivity. Recently, some boryllithium species have been reported as a base or a nucleophile in reaction with organic electrophiles in S(N)2 reactions. In the present work, the proton affinity (PA) of boryllithium compounds was calculated. These values can be useful as theoretical reference values and to provide valuable complementary information for the interpretation and discussion of the basicity of these compounds. The proton affinity was calculated using a theoretical method based on density functional theory and high-level theoretical methods through MP2 and G2MP2 levels of theory. In addition, some global and local reactivity indexes based on density functional theory (DFT) on boryllithium compounds were studied. In order to compare and discuss the chemical reactivity of these compounds, some analogues and electrophilic boron compounds were also studied. Our results showed a local and global nucleophilic reactivity of the boryllithium molecules in agreement with the experimental reactivity. The boryllithium compounds revealed to be strong bases in comparison to other analogue compounds studied in this work.
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The energy of the frontier molecular orbitals and reactivity indices such as chemical potential, hardness, and electrophilicity of neutral and charged molecules have been investigated in aqueous solution using explicit model for the solvent with the sequential Monte Carlo/quantum mechanics methodology. The supermolecular structures of the solute-solvent system were generated by Monte Carlo simulation. Statistically uncorrelated structures have been extracted for quantum mechanical calculations of the solute surrounded by the first solvation shell, using explicit water molecules, and the second and third shells as atomic point charges. The supermolecular calculations treating both the solute and the solvent explicitly were performed within density functional theory. The solvent dependence of the frontier molecular orbital energies was analyzed and used to calculate the reactivity indices in solution. The dependence of the results with respect to the number of explicit solvent molecules is also analyzed. It is seen that for the systems considered here, the energies of the highest occupied molecular orbital and the lowest unoccupied molecular orbital show a strong dependence with the number of solvent molecules. However, the properties derived from these are relatively stable. In particular, the results reported here for the reactivity indices obtained using the first solvation shell are similar to those obtained for the limit bulk value. For comparison, the reactivity indices were also calculated in the gas phase and using the polarizable continuum model (PCM). As frequently reported in the literature, neutral molecules do not show significant changes in the reactivity indices between gas phase and the PCM model. However, with the explicit solvent model some important changes were observed: a larger negative chemical potential, a smaller hardness, and a larger electrophilicity. The stabilization of an anion corresponding to a negative chemical potential is obtained only by using explicit solvent molecules. In general, the solvent effect was well treated by using the first solvation shell, and the calculated results are in agreement with the experimental trends. The delocalization of the solute orbitals over the solvent region is analyzed, and its consequence to the reactivity indices are discussed. The importance of including explicit solvent molecules and adopting a statistical approach for the liquid is emphasized.
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This work deals with exploring some empirical scales of nucleophilicity. We have started evaluating the experimental indices of nucleophilicity proposed by Legon and Millen on the basis of the measure of the force constants derived from vibrational frequencies using a probe dipole H-X (X = F,CN). The correlation among some theoretical parameters with this experimental scale has been evaluated. The theoretical parameters have been chosen as the minimum of the electrostatic potential V(min), the binding energy (BE) between the nucleophile and the H-X dipole, and the electrostatic potential measured at the position of the hydrogen atom V(H) when the complex nucleophile and dipole H-X is in the equilibrium geometry. All of them present good correlations with the experimental nucleophilicity scale. In addition, the BEs of the nucleophiles with two other Lewis acids (one hard, BF(3), and the other soft, BH(3)) have been evaluated. The results suggest that the Legon and Millen nucleophilicity scale and the electrostatic potential derived scales can describe in good approximation the reactivity order of the nucleophiles only when the interactions with a probe electrophile is of the hard-hard type. For a covalent interaction that is orbital controlled, a new nucleophilicity index using information of the frontier orbitals of both, the nucleophile and the electrophile has been proposed.
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OBJETIVOS. Analizar nuestros pacientes con pólipos gástricos con respecto a las características demográficas, histopatológicas, clínicas y endoscópicas, y la relación con el consumo de bloqueadores de bomba.MÉTODOS. Se revisaron retrospectivamente las historias clínicas y los reportes histológicos de los pacientes con pólipos gástricos. Casi todas las lesiones se removieron con pinzas de biopsia o asa de polipectomía. Se contactaron telefónicamente 117 pacientes para determinar si había o no consumo de bloqueadores de bomba y el tiempo de este consumo.RESULTADOS. Se encontraron pólipos en 150 pacientes. En 42 hombres (28 por ciento) y 108 mujeres (72 por ciento) con una edad promedio de 56 años (rango de 18 a 88 años). El síntoma más frecuente fue la dispepsia en 69 pacientes (46 por ciento). Los síntomas se relacionaron más con las anomalías gástricas asociadas que por la presencia de los pólipos. Los pólipos se ubicaron más frecuentemente en el fondo gástrico (39 por ciento), seguido por el antro (35 por ciento). De los 150 pacientes, en 69 (46 por ciento) se encontraron pólipos de 5 mms o menos y sólo 4 fueron pediculados. La frecuencia de los pólipos hiperplásicos, inflamatorios y glándulo-fúndicos fue de 55 por ciento, 18 por ciento y 9 por ciento. Se detectaron 5 pacientes con pólipos adenomatosos, tumores carcinoides en 5, GIST en 5 y otros 12 pacientes con diferentes pólipos epiteliales benignos. Se encontraron seis pacientes con cambios adenomatosos en pólipos hiperplásicos. La evaluación histológica de la mucosa gástrica vecina demostró gastritis crónica en 131 pacientes (87 por ciento) y en 87 (58 por ciento) había infección por helicobacter pylori. El consumo promedio de bloqueadores de bomba fue de 6 meses para las diferentes variantes histológicas excepto para los pólipos carcinoides que tenían un consumo de 20 meses.CONCLUSIONES. Los pólipos hiperplásicos son los pólipos más frecuentemente encontrados y la ubicación más usual fue en el cuerpo y...