Resumen Introducción: la nutrición parenteral es una mezcla de macro y micronutrientes necesarios para el prematuro que no puede alimentarse por vía enteral. La mezcla binaria contiene en una bolsa carbohidratos, proteínas y micronutrientes y en otra los lípidos intravenosos, que son más susceptibles de contaminación microbiana especialmente por Candida albicans, por lo que asociaciones profesionales recomiendan el uso en línea “y” de un solo filtro, lo que no es práctica habitual hospitalaria. Objetivo: determinar la presencia de Candida albicans en dispositivos que contienen lípidos intravenosos usados en neonatos y relacionarla con el uso correcto del filtro de 1.2 µm. Método: se evaluaron tres grupos de muestras constituidas por los restos de una solución de lípidos (ML) administrados al paciente prematuro durante 24 h. sembradas en agar Sabouraud organizadas en: (ML1): solución de lípidos obtenida directamente de la bolsa de etinil vinil acetato (EVA). (ML2): solución de lípidos filtrados con dispositivo de 1.2 µm. conectado directamente al catéter (práctica observada). (ML3): solución de lípidos contaminados con Candida que fueron sembrados en agar Sabouraud y posteriormente filtrados. Resultados: el 100 % de las muestras filtradas (ML2) y (ML3) como se esperaba, no presentaron Candida albicans, el 100 % de las muestras (ML1) que no fueron filtradas, tampoco presentaron Candida albicans. Conclusiones: no hubo presencia de Candida albicans en las soluciones lipídicas utilizadas directamente con filtro 1.2 µm, sin embargo, se recomienda el uso de un solo filtro 1.2 µm en línea “Y” según las normas internacionales para el ahorro del Sistema sanitario.

Abstract Introduction: parenteral nutrition is a mixture of macro and micronutrients necessary for the premature infant who cannot be fed enterally. The binary mixture contains carbohydrates, amino acids and micronutrients in one bag and intravenous lipids in another. The latter are more susceptible to microbial contamination, especially by Candida albicans. For this reason, many professional associations typically recommend the use of a single filter in line “Y”; however, this has not yet become standard hospital practice. Aim: to determine the presence of Candida albicans in devices that contain intravenous lipids used in neonates and relate it to the correct use of the 1.2 µm filter. Method: three groups of samples consisting of the remains of a lipid solution (ML) administered to the premature patient for 24 h seeded on Sabouraud agar organized as follows: (ML1), lipid solution obtained directly from the ethinyl vinyl acetate bag were evaluated. (ML2): filtered lipid solution with a 1.2 µm device connected directly to the catheter. (ML3): solution of lipids intentionally contaminated with Candida and subsequently filtered. Results: Candida albicans was not detected in any of the filtered simples (ML2 and ML3) and also not detected in any of the unfiltered simples (ML1). Conclusions: there was no presence of Candida albicans in the lipid solutions used directly with a 1.2 µm filter, however, the use of a single 1.2 µm filter in line “Y” is recommended according to international standards to save the health system.

Abstract Introduction: Helicobacter pylori infection plays a critical role in the carcinogenesis cascade of intestinal gastric cancer. However, its prevalence in preneoplastic conditions generating changes in the gastric mucosa is unclear. Currently, endoscopic surveillance using the Sydney protocol is suggested every 2 to 3 years, but the presence of H. pylori infection in the subcardial region and gastric fundus is ill-defined. Objective: to determine the prevalence and gastric location of H. pylori infection in patients with preneoplastic conditions. Materials and methods: a cross-sectional study in adults with a previous diagnosis of atrophy or intestinal metaplasia who entered control endoscopy and were antrum, body, incisura angularis, subcardial region, and gastric fundus biopsied. A descriptive analysis of the results by gastric regions was performed. Results: data from 160 patients with a prevalence of H. pylori of 37.5% were collected. It increased from proximal to distal, starting with a 12.5% prevalence in the subcardial region to a 30.6% prevalence in the antrum. In addition, there was a similar pattern in the prevalence of preneoplastic lesions. Furthermore, advanced lesions (dysplasia, carcinoma) were observed in the incisura. Conclusions: the prevalence of H. pylori in precancerous conditions showed a high presence in the distal regions compared to the proximal ones, and it is more frequent in the antrum and lower in the subcardial region. As for the gastric distribution of atrophy and metaplasia, more involvement was found in the antrum and angular notch and lower in the subcardial region and fundus.

Resumen Introducción: Helicobacter pylori juega un papel fundamental en la cascada de carcinogénesis del cáncer gástrico tipo intestinal; sin embargo, no existe claridad respecto a su prevalencia en condiciones preneoplásicas que generan cambio en el microambiente de la mucosa. Actualmente se recomienda la vigilancia endoscópica por protocolo de Sydney cada 2 a 3 años, pero no es clara la presencia de H. pylori en la región subcardial y el fondo gástrico. Objetivo: determinar la prevalencia y localización gástrica del H. pylori en pacientes con condiciones preneoplásicas. Materiales y métodos: estudio de corte transversal en adultos con diagnóstico previo de atrofia o metaplasia intestinal que ingresaron a endoscopia de control, a quienes se les tomaron biopsias del antro, cuerpo, incisura angularis, región subcardial y fondo gástrico. Se realizó un análisis descriptivo de los resultados por regiones gástricas. Resultados: se recolectó la información de 160 pacientes con una prevalencia de H. pylori del 37,5 %, la cual fue en aumento de proximal a distal iniciando con una prevalencia de 12,5 % en la región subcardial hasta una prevalencia de 30,6 % en el antro; hubo un patrón similar en la prevalencia de lesiones preneoplásicas. Se observó una mayor presencia de lesiones avanzadas (displasia, carcinoma) en la incisura. Conclusiones: la prevalencia de H. pylori en condiciones premalignas evidenció una mayor presencia en las regiones distales en comparación con las proximales, y es más frecuente en la región antral y menor en la región subcardial. En cuanto a la distribución gástrica de atrofia y metaplasia, se encontró mayor compromiso en el antro y la incisura, y es baja en la región subcardial y el fondo.

Abstract Background: Esophagojejunal anastomotic leakage (EJAL) is among the most feared complications after gastric cancer surgery; they entail an uncertain prognosis and relate with increased morbidity and mortality. Factors associated with their development are not well determined, and their diagnosis and treatment vary between institutions. Material and methods: Retrospective case-control study of patients operated of total gastrectomy with Roux-en-Y esophagojejunostomy from January 2002 to December 2018. We divided our sample into two groups based on the presence of EJAL, and compared demographic, clinical, and histologic variables. We performed a logistic regression model to search risk factors associated with EJAL and described the management offered in our center. Results: We included 58 patients of which 8 (13.7%) presented clinically relevant EJAL. On the comparative analysis, albumin levels and diffuse histology presented a statistically significant difference between groups and presented association with EJAL in the logistic regression model. Regarding treatment of EJAL, ten patients (55.5%) required only conservative measures, whereas eight patients (44.4%) warranted an endoscopic or surgical intervention. Conclusion: Our retrospective analysis identified some factors that may be associated with the development of EJAL after gastric cancer surgery. High suspicion and prompt identification of this complication is essential to improve postoperative outcomes in this group.

Resumen Introducción: Las fugas de la anastomosis esófago-yeyunal se encuentran entre las más temidas complicaciones de la cirugía para cáncer gástrico. Estas conllevan un mal pronóstico con una alta mortalidad y morbilidad. Los factores asociados a su desarrollo no están bien determinados y su diagnóstico, y tratamiento varían ampliamente entre instituciones. Material y métodos: Estudio retrospectivo de casos y controles en pacientes operados de gastrectomía total con esófago-yeyuno anastomosis en Y de Roux en el periodo de enero 2002 a diciembre 2018. Nuestra muestra fue dividida en dos grupos con base al desarrollo de fuga de anastomosis en el postoperatorio. Se realizó un análisis comparativo de características demográficas, clínicas y histológicas. Se realizó además una regresión logística para identificar factores de riesgo asociados al desarrollo de fuga de anastomosis en nuestra serie. Resultados: Incluimos a 58 pacientes de los cuales 8 (13.7%) presentaron fuga de anastomosis clínicamente relevante. En el estudio comparativo: Niveles disminuidos de albúmina e histología difusa fueron significativamente mayores en el grupo de fuga y se asociaron en el modelo de regresión logística. En cuanto al tratamiento, diez pacientes (55%) requirieron únicamente tratamiento conservador, mientras que ocho pacientes (44.4%) fueron sometidos a maniobras endoscópicas o quirúrgicas. Conclusión: Nuestro análisis retrospectivo identifico factores asociados al desarrollo de fuga de anastomosis posterior a cirugía de cáncer gástrico. Una alta sospecha diagnóstica es esencial para mejorar el pronóstico de estos pacientes.

Resumen Bajo las nuevas condiciones generadas por la pandemia de COVID-19, los tratamientos para el cáncer de mama requieren algunas reorientaciones y cuidados que se exponen en este artículo. Se consideran aquí las tres fases de gravedad de la pandemia y los respectivos tratamientos que demandan en función de los lineamientos dictados por el Ministerio de Salud y Protección Social de Colombia. Se trata de un conjunto de referencias para orientar las terapias y tratamientos, inspiradas en las políticas de salud regionales, nacionales e institucionales.

Abstract Under the new conditions generated by the COVID-19 pandemic, breast cancer treatments requires some reorientations and cares that are discussed in this article. The three phases of severity of the pandemic and the respective treatments they require -based on the guidelines issued by the Ministry of Health and Social Protection of Colombia- are considered here. It is a set of references to guide therapies and treatments, inspired by regional, national and institutional health policies.

Abstract Introduction: Reconstruction of the abdominal wall with major defects usually represents a surgical challenge, especially in cases where the defects are recurrent and have a large size that avoids the use of adjacent tissues for an adequate closure. According to each region the abdomen topography is divided into three regions: upper, middle and lower. Several reconstructive alternatives have been described according to the affected area of the abdomen that include the separation of the muscularis aponeurotic components of the abdominal rectus sheath, the flap of the rectus abdominus muscle with or without cutaneous island, the flap dependent on the dorsal muscle and muscular or musculocutaneous thigh flaps to reconstruct the lower area of the abdomen which is called anterolateral thigh (ALT) flap. The ALT flap has become the best option for large recurrent defects in any of the thirds due to its great versatility. Case report: We present the case of a 50-year-old patient with an abdominal wall defect, loss of domain and exposure of prosthetic material. Patient had a surgical history of open cholecystectomy, necrosectomy due to acute pancreatitis with open abdomen management and attempted repair of the abdominal defect twice with mesh placement. The abdominal wall was reconstructed with an ALT free flap with a fascia lata component with anastomosis to superior epigastric vessels in a successful manner. Nowadays patient remains without evidence of recurrence of the hernia at 1 year follow-up. Discussion/conclusion: The aim of this paper is to illustrate the ALT flap with a fascia lata component anastomosed to the superior epigastric vessels as a good option to reconstruct complex defects of the upper third of the abdomen.

Resumen Introducción: La reconstrucción de la pared abdominal con grandes defectos suele representar un desafío quirúrgico, sobre todo cuando los defectos son recurrentes y tienen un gran tamaño que dificulta la utilización de tejidos adyacentes para un cierre adecuado. La pared abdominal anterior se divide en tres regiones para su reconstrucción; superior, media e inferior. De acuerdo con cada región se han descrito diferentes técnicas de reconstrucción de pared, como la separación de componentes musculoaponeuróticos de la vaina de los rectos abdominales, el colgajo del músculo recto abdominal con o sin isla cutánea, el colgajo dependiente del músculo dorsal ancho y colgajos musculares o músculocutáneos del muslo para reconstruir el tercio inferior del abdomen, llamado colgajo anterolateral de muslo (ALT, por sus siglas en inglés). El ALT se ha convertido en una buena alternativa para los grandes defectos recurrentes en cualquiera de los tercios debido a su gran versatilidad. Caso clínico: Presentamos el caso de un paciente de 50 años con un defecto de pared abdominal, pérdida de dominio y exposición de material protésico (malla). Tenía el antecedente quirúrgico de colecistectomía abierta, necrosectomía por pancreatitis aguda con manejo de abdomen abierto (incisión en línea media supra-infraumbilical) e intento de reparación del defecto abdominal en dos ocasiones con colocación de malla (que se encontraba expuesta). El defecto existente se desmanteló y resecó en bloque desde el interior de la pared abdominal, dejando bordes aponeuróticos sanos, quitando todo el tejido cicatricial, la malla y los bordes cutáneos enfermos. Se realizó la reconstrucción de la pared abdominal con ALT con un componente de fascia lata con anastomosis a vasos epigástricos superiores, de manera exitosa. Actualmente no hay evidencia de recurrencia del defecto herniario tras 1 año de seguimiento. Discusión/conclusión: El objetivo de este trabajo es describir el ALT con componente de fascia lata con anastomosis a los vasos epigástricos superiores como una buena alternativa para reconstruir defectos de pared complejos del tercio superior del abdomen.

Abstract Introduction: Multi-frequency bio-impedance analysis (BIA) accurately evaluates body composition. Objective: To assess nutritional status and its relationship with body mass index (BMI) or with BIA-obtained phase angle in patients with end-stage renal disease (ESRD) on hemodialysis. Method: BMI, BIA and dialysis malnutrition score (DMS) were assessed in 99 patients on hemodialysis (43.6 ± 17.2 years of age, 58.8% males). Multivariate linear regression analysis was used to determine BMI and phase angle independent associations with DMS. Results: Malnutrition risk (DMS > 13) showed a gradual increase among patients with normal BMI and phase angle (44.4%), low BMI (45.8%), low phase angle (64.0%), and in those with both parameters at abnormal ranges (68.0%). The phase angle was the only variable that was independently associated with patient nutritional status (standardized coefficient beta −0.372, p < 0.001), accounting for 13.8% of DMS variation. Conclusion: Phase angle is inversely and independently associated with malnutrition risk in patients with ESRD, which suggests that BIA-assessed body composition might be better than BMI in the clinical assessment of patients with ESRD.

Resumen Introducción: La bioimpedancia eléctrica multifrecuencia (BIE) evalúa con precisión la composición corporal. Objetivo: Investigar el estado nutricional y su relación con el índice de masa corporal (IMC) o el ángulo fase obtenido por BIE en pacientes con enfermedad renal terminal (ERT) en hemodiálisis. Método: En 99 pacientes en hemodiálisis (43.6 ± 17.2 años, 58.8 % varones) se evaluó IMC, BIE y puntuación de desnutrición (DMS, Dialysis Malnutrition Score). La independencia de las asociaciones del IMC y el ángulo fase con el DMS se determinó con regresión lineal múltiple. Resultados: El riesgo de desnutrición (DMS > 13) se incrementó gradualmente entre los sujetos con IMC y ángulo fase normales (44.4 %), IMC bajo (45.8 %), ángulo fase bajo (64.0 %) y en aquellos con ambos parámetros anormales (68.0 %). El ángulo fase fue la única variable asociada independientemente con el estado nutricional de los pacientes (coeficiente beta estandarizado −0.372, p < 0.001), lo que explicó 13.8 % de la variación en el DMS. Conclusiones: El ángulo fase se asocia inversa e independientemente con el riesgo de desnutrición en pacientes con ERT, lo que sugiere que la composición corporal evaluada por BIE pudiera ser mejor que el IMC en la valoración clínica de pacientes con esta enfermedad.

Abstract Introduction: Retroperitoneal tumors are rare; they account for 0.3-0.8% of neoplasms in general. Even with the medical-technological advances, they symbolize a diagnostic problem and, moreover, a great therapeutic challenge, since they put the patients at high risk, not only for the histological aggressiveness of most subtypes, but also for their proximity to neurovascular structures. Case Report: A 57-year-old female, with diagnosis of dyslipidemia and medical history of posterior deep vein thrombosis, after resection of extravascular leiomyoma in the right atrium, and partial section of the inferior vena cava. She went to the clinic for evaluation due a possible uterine-dependent pelvic tumor, classified as probable uterine myomatosis. Transvaginal ultrasound was performed, and revealed intramural myomatosis with calcium degeneration and solid retroperitoneal mass of pyriform shape with dimensions of 95 mm × 37 mm. A supra and infraumbilical medial approach was performed, where right lateral retroperitoneal tumor was identified by Cattel Braasch maneuver. In addition, the deep iliac vein was identified, which presented a 9 cm × 5 cm tumor, with stenosis at 2 cm from the bifurcation of the inferior vena cava, and proximal dilatation. The patient evolved appropriately, being discharged at 48 h. Discussion: Neurilemoma or schwannoma is a tumor arised from the peripheral nerve sheath that originates from the Schwann cells; they are a subclass of soft tissue tumors including: the neurofibroma, the solitary circumscribed neuroma, and the perineurioma. The exact etiology and pathogenesis of schwannomas remain unclear. Schwannomas are usually solitary, slow-growing and painless, predominating in women between the second and fifth decade of life. For this reason, they are usually identified incidentally during routine physical examinations or imaging studies as happened in our case.

Resumen Introducción: Los tumores retroperitoneales son poco frecuentes, representan entre el 0.3 y el 0.8% de las neoplasias en general. A pesar de los avances médicos y tecnológicos, ofrecen un reto diagnóstico y, más aún, un gran desafío terapéutico, ya que suponen un elevado riesgo, no solo por la agresividad histológica de la mayoría de los subtipos, sino por su cercanía a estructuras neurovasculares. Caso clínico: Paciente femenino de 57 años, con diagnóstico de dislipidemia y antecedente de trombosis venosa profunda posterior, tras resección de leiomioma extravascular en aurícula derecha y sección parcial de vena cava inferior. Acudió a consulta externa para valoración por probable tumoración pélvica dependiente de útero, catalogada como probable mixomatosis uterina. El ultrasonido (US) transvaginal reveló miomatosis intramural con degeneración cálcica y masa sólida retroperitoneal de forma piriforme con dimensiones de 95 x 37 mm. Se realizó abordaje medial supra e infraumbilical, en donde fue identificado tumor retroperitoneal lateral derecho mediante maniobra de Cattel Braasch. Asimismo, se identificó la vena ilíaca profunda, la cual presentaba tumoración de 9 x 5 cm, con estenosis a 2 cm de la bifurcación de la vena cava inferior, y dilatación proximal. La paciente evolucionó de manera adecuada, siendo egresada a las 48 horas. Discusión: El neurilemoma o schwannoma es un tumor poco frecuente, proveniente de la vaina nerviosa periférica que se origina de las células de Schwann; es una subclase de tumores de tejidos blandos que incluye al neurofibroma, al neuroma circunscrito solitario y al perineurioma. La etiología exacta y la patogénesis de los schwannomas siguen siendo poco claras. Los schwannomas son generalmente solitarios, de crecimiento lento e indoloro, y predominan en mujeres entre la segunda y la quinta década de vida; por este motivo suelen ser identificados incidentalmente durante exámenes físicos ordinarios o en estudios de imagen, como sucedió en nuestro caso.

Introduction: radiosynoviorthesis is used in treating chronic synovitis, a frequent complication of some systemic diseases as rheumatoid arthritis and hemophilia. There are different colloids and radioactive suspensions recommended in the international clinical practice, but the number is reduced and the availability limited. Objective: obtaining and physical-chemical characterization of suspensions of chromium phosphate (III) labeled with several radionuclides as potential radiopharmaceuticals for using in radiosynoviorthesis. Methods: the suspensions were obtained by chemical synthesis. Radionuclides were added at the beginning or after concluding the reaction. The particle size was estimated by means of optic microscopy and membrane filtration. Similarly, the stability of suspension when re-suspended in several media was evaluated by spectrophotometry. The radiochemical purity was determined by paper chromatography. Results: a suspension of chromium (III) phosphate was obtained and characterized. It was found that the obtained product had a predominant particle size range of 0,8 to 5 µm and that when suspended in 2 % gelatin solution in 1mg/ml acetate buffer, it settled in no less than 3 hours. Technologies for the preparation of radiopharmaceuticals of Chromium (III) Phosphate labeled with 32P and 90Y were described. There was demonstrated the feasibility of labeling the obtained suspension with other trivalent radionuclides such as 177Lu and 68Ga. Conclusions: the results allow considering the obtained Chromium (III) Phosphate suspension as a matrix for the preparation of radiopharmaceuticals to be used in radiosinoviorthesis aimed at various joints, depending on the physical and nuclear characteristics of the radionuclides.

Introducción: la radiosinoviortesis se utiliza en el tratamiento de la sinovitis crónica, complicación frecuente en enfermedades sistémicas como artritis reumatoide y hemofilia. En la práctica clínica internacional se emplean diferentes coloides y suspensiones radiactivas, pero su número es reducido y su disponibilidad limitada. Objetivo: obtención y caracterización físico-química de suspensiones de fosfato de cromo (III) marcadas con radionúclidos como potenciales radiofármacos para uso en radiosinoviortesis. Métodos: las suspensiones se obtuvieron por síntesis química, los radionúclidos se añadieron al inicio de la reacción o después de finalizada esta. El tamaño de partículas se estimó mediante microscopia óptica y filtración por membranas. Asimismo se evaluó por espectrofotometría la estabilidad de la suspensión al ser resuspendida en distintos medios. La pureza radioquímica se determinó por cromatografía de papel. Resultados: se obtuvo y caracterizó una suspensión de fosfato de cromo (III). El producto obtenido presentó un tamaño de partículas predominante entre 0,8-5 µm y que al ser suspendidas en solución de gelatina al 2 % en tampón acetato 1 mg/mL no sedimentó en menos de 3 h. Se estableció la tecnología para la obtención de formulaciones de fosfato de cromo (III) marcado con 32P e 90Y y se demostró la factibilidad de marcar la suspensión obtenida con otros radionúclidos trivalentes como 177Lu y 68Ga. Conclusiones: los resultados permiten considerar al fosfato de cromo (III) una suspensión base para la obtención de radiofármacos para uso en radiosinoviortesis en diferentes articulaciones, en función de las características físico-nucleares de los radionúclidos que se empleen.

In 1944 the Sociedad Botánica de México (Botanical Society of Mexico) launched a scientific journal with the aim of disseminating the botanical research conducted in Mexico; at that time the journal bore the very short title of Boletín. Through the decades that followed this journal has undergone a series of changes, including the title (it took the title Boletín de la Sociedad Botánica de México), format and content. The purpose of this paper is to introduce the new title of the journal, Botanical Sciences, and additional changes whose objective is to consolidate its prime role in the Mexican scientific arena and the international level acquired by this journal, both of which are characteristics that reflect the growth and maturity of the academic and professional organization responsible for its publication.

En 1944 la Sociedad Botánica de México comenzó a publicar una revista científica con el objetivo de dar a conocer la investigación botánica realizada en México, llevando en ese entonces el escueto título de Boletín. A través de las décadas esta publicación periódica ha tenido una serie de transformaciones, desde su nombre (pasó a llamarse Boletín de la Sociedad Botánica de México) hasta diversos aspectos de formato y contenido. En este trabajo se da a conocer el nuevo nombre de la revista, Botanical Sciences, el cual va acompañado de varias adecuaciones cuyo objetivo es consolidar el papel primordial que ha alcanzado la revista en la difusión de la investigación botánica en los ámbitos nacional e internacional. Estas características son sin duda un reflejo del crecimiento y la madurez de la organización académica y profesional responsable de su publicación.

A potenciação de longa duração (LTP) é o aumento de respostas pós-sinápticas durante horas, dias ou semanas após a breve estimulação repetitiva de aferentes pre-sinápticos. Foi proposto durante 30 anos ser a base da memória de longa duração. Vários achados recentes finalmente apoiaram esta hipótese: a) a formação da memória de esquiva inibitória adquirida numa sessão depende de uma cadeia de processos moleculares na região CA1 do hipocampo quase idêntica à da LTP nessa mesma região; b) LTP hipocampal nessa região acompanha a formação da memóría dessa tarefa e de outra semelhante. No entanto, a LTP de CA1 e os processos de memória podem ser dissociados e, fora disso, processos plásticos em outras regiões cerebrais (amígdala, córtex entorrinal, córtex parietal) também são necessários para a formação da memória da tarefa de uma sessão e talvez de muitas outras.

Long-term potentiation (LTP) is the enhancement of postsynaptic responses for hours, days or weeks following the brief repetitive afferent stimulation of presynaptic afferents. It has been proposed many times over the last 30 years to be the basis of long-term memory. Several recent findings finally supported this hypothesis: a) memory formation of one-trial avoidance learning depends on a series of molecular steps in the CA1 region of the hippocampus almost identical to those of LTP in the same region; b)hippocampal LTP in this region accompanies memory formation of that task and of another similar task. However, CA1 LTP and the accompanying memory processes can be dissociated, and in addition plastic events in several other brain regions(amygdala, entorhinal cortex, parietal cortex) are also necessary for memory formation of the one-trial task, and perhaps of many others.

Theobroma cacao L. es una especie originaria de América y ha estado ligada al desarrollo de diversas culturas indígenas en las regiones tropicales húmedas. Su semilla se utiliza para la elaboración de alimentos, bebidas y golosinas y su demanda se ha incrementado cuando se cultiva sin agroquímicos. La nutrición de la planta mediante biofertilizantes microbianos es una alternativa para incrementar la oferta de cacao orgánico. En este trabajo se identificó el aporte de dos microsimbiontes en el desarrollo vegetal y nutrimental del cacao en dos condiciones de suelo del Soconusco, Chiapas, México, uno de ellos tratado con bromuro de metilo y otro sin tratar. Las semillas de cacao se inocularon con Azospirillum brasilense y Glomus intraradices, solos o combinados al momento de la siembra. Se registraron variables morfológicas y fisiológicas del rendimiento y el contenido de N2, P y Ca2+ en el tejido vegetal cada 30 días durante seis meses. Los resultados indicaron una respuesta diferencial entre condiciones de suelo y microsimbiontes en la asignación de materia seca. Los órganos de la planta más modificados fueron la raíz y la lámina foliar. Las plantas inoculadas mostraron mayor concentración de N2 en suelo no tratado. G. intraradices fue más efectivo en promover la incorporación de P en suelo no tratado y de Ca2+ en ambas condiciones del suelo.

Theobroma cacao L. originated in America and has been associated with the development of various Indian cultures in the tropical forest. Its beans are used for the production of food, beverages and sweets. The demand of cocoa cultivated without agrochemical products has increased. Plant nutrition with microbial fertilizers is an alternative for increasing its organic production. In this experiment the contribution of two micro organisms to the development and nutritive characteristics of cocoa was determined under two soil conditions, treated with methyl bromide or untreated, in the Soconusco region, Chiapas, Mexico. The cocoa beans were inoculated with Azospirillum brasilense and Glomus intraradices, alone or in combination at sowing. Morphological and physiological characters, and the N2, P and Ca2+ content in the vegetal tissue were recorded every 30 days for six months. The results indicate a differential response for soil condition and micro organisms in the production of dry matter. Root and foliar lamina were the most affected organs. The inoculated plants showed a higher N2 concentration. G. intraradices translocated more P in the untreated soil and more Ca2+ under either soil conditions.

Theobroma cacao L. é uma espécie originária de América e tem estado relacionada ao desenvolvimento de diversas culturas indígenas nas regiões tropicais úmidas. Sua semente se utiliza para a elaboração de alimentos, bebidas e guloseimas e sua demanda tem se incrementado quando se cultiva sem agroquímicos. A nutrição da planta mediante biofertilizantes microbianos é una alternativa para incrementar a oferta de cacau orgânico. Neste trabalho se identificou a contribuição de dois microsimbiontes no desenvolvimento vegetal e nutrimental do cacau sob duas condições de solo do Soconusco, Chiapas, México, um deles tratado com bromuro de metilo e o outro sem tratar. As sementes de cacau foram inoculadas com Azospirillum brasilense e Glomus intraradices, sozinhos ou combinados no momento da plantação. Registraram-se variáveis morfológicas e fisiológicas do rendimento e o conteúdo de N2, P e Ca2+ no tecido vegetal a cada 30 dias durante seis meses. Os resultados indicaram uma resposta diferencial entre condições de solo e microsimbiontes na designação de matéria seca. Os órgãos da planta mais modificados foram a raiz e a lâmina foliar. As plantas inoculadas mostraram maior concentração de N2 em solo não tratado. G. intraradices foi mais efetivo em promover a incorporação de P em solo não tratado e de Ca2+ em ambas as condições do solo.

Brain calcifications, most frequently due to residual cysticercosis, are very common in developing countries. Recent reports have shown that residual brain lesions may be enhanced after contrast and present edema after an episode of neurological symptoms. We report three cases showing this phenomenon and how it can complicate the diagnosis, increasing hospital stay, and sometimes requiring invasive diagnostic procedures. Calcifications with surrounding edema must be considered in the differential diagnosis of enhancing brain lesions.

Las calcificaciones del parénquima cerebral, mayormente atribuidas a neurocisticercosis residual, son comunes en países en vías de desarrollo. Recientemente se ha reportado que aún las lesiones calcificadas residuales pueden presentar captación de contraste y edema, detectables al tiempo de una manifestación neurológica. Presentamos tres casos que demuestran como este fenómeno puede innecesariamente complicar el diagnósltico, incrementando el tiempo de hospitalización y en algunas veces hasta practicar procedimientos invasivos para confirmar el diagnóstico. Las calcificaciones con edema perilesional deben ser consideradas en el diagnóstico diferencial de las lesiones granulomas intracerebrales.

Ao longo dos anos, têm-se identificado dois sistemasprincipais de memória (Squire 1992): o sistema das memórias declarativas, que está sob o controle do hipocampo e estruturas relacionadas do lobo temporal e o sistema das memórias procedimentais ou memórias para hábitos, que está sob controle do corpo estriado e suas conexões. Porém, quase todas as tarefas de aprendizado utilizadas para estudar a formação de memórias em animais envolvem a realização ou a supressão de movimentos e, se bem aprendidas poderia interpretar-se que essas memórias se converteram em um hábito. Sabe-se que os processos envolvidos na formação de memórias mudam na medida em que a associação original torna-se fortalecida através do treinamento. Será que esta mudança também envolve a passagem de um sistema de memória para outro? Aqui nós iremos comentar a respeito 1) do aprendizado reverso na tarefa do labirinto aquático de Morris (LAM), na qual o componente declarativo da tarefa muda, mas o componente procedimental (nadar para um lugar seguro) persiste e precisa ser re-associado a um grupo distinto de dicas espaciais e 2) a respeito de uma série de observações relacionadas com a tarefa de esquiva inibitória que indicam que os sistemas neurais envolvidos no processamento mnemônico mudam na medida em que o aprendizado original é reforçado.

Two major memory systems have been recognized over the years (Squire 1987): the declarative memory system, which is under the control of the hippocampus and related temporal lobe structures, and the procedural or habit memory system, which is under the control of the striatum and its connections. Most if not all learning tasks studied in animals, however, involve either the performance or the suppression of movement; this, if learned well, may be viewed as having become a habit. It is agreed that memory rules change from their first association to those that take place when the task is mastered. Does this change of rules involve a switch from one memory system to another? Here we will comment on: 1) reversal learning in the Morris water maze (MWM), in which the declarative or spatial component of a task is changed but the procedural component (to swim to safety) persists and needs to be re-linked with a different set of spatial cues; and 2) a series of observations on an inhibitory avoidance task that indicate that the brain systems involved change with further learning.

A retenção das memórias é avaliada através da sua expressão. A expressão do traço mnemônico é iniciada freqüentemente pelo estímulo condicionado (CS); porém, como definido por Pavlov, a apresentação apenas do CS induz extinção. A esquiva inibitória de apenas uma sessão (IA) é um paradigma de condicionamento ao medo muito utilizado, no qual o CS é a parte segura da caixa de treinamento (plataforma), o estímulo incondicionado (US) é um choque aplicado nas patas do animal quando o mesmo desce da plataforma e a resposta condicionada é permanecer na área segura. Na IA, a expressão da memória é medida na ausência do US, sendo definida como a latência para descer da área segura. A extinção é instalada no momento da primeira sessão de teste, tal como fica claramente demonstrado pelo fato de que várias drogas, entre elas inibidores de síntese protéica, de PKA e de ERK e antagonistas dos receptores NMDA, impedem a extinção quando administrados no hipocampo ou na amígdala basolateral no momento da primeira sessão de teste, mas não mais tardiamente. Alguns, mas não todos os sistemas moleculares requeridos para a extinção, também são ativados pela expressão das memórias, fortalecendo a hipótese de que mesmo que a expressão seja comportamental e bioquimicamente necessária para a ocorrência da extinção, este último processo constitui um novo aprendizado, secundário a expressão do traço original.

Memory is measured by measuring retrieval. Retrieval is often triggered by the conditioned stimulus (CS); however, as known since Pavlov, presentation of the CS alone generates extinction. One-trial avoidance (IA) is a much used conditioned fear paradigm in which the CS is the safe part of a training apparatus, the unconditioned stimulus (US) is a footshock and the conditioned response is to stay in the safe area. In IA, retrieval is measured without the US, as latency to step-down from the safe area (i.e., a platform). Extinction is installed at the moment of the first unreinforced test session, as clearly shown by the fact that many drugs, including PKA, ERK and protein synthesis inhibitors as well as NMDA receptor antagonists, hinder extinction when infused into the hippocampus or the basolateral amygdala at the moment of the first test session but not later. Some, but not all the molecular systems required for extinction are also activated by retrieval, further endorsing the hypothesis that although retrieval is behaviorally and biochemically necessary for the generation of extinction, this last process constitutes a new learning secondary to the unreinforced expression of the original trace.

Since William James (1890) first distinguished primary from secondary memory, equivalent to short- and long-term memory, respectively, it has been assumed that short-term memory processes are in charge of cognition while long-term memory is being consolidated. From those days a major question has been whether short-term memory is merely a initial phase of long-term memory, or a separate phenomena. Recent experiments have shown that many treatments with specific molecular actions given into the hippocampus and related brain areas after one-trial avoidance learning can effectively cancel short-term memory without affecting long-term memory formation. This shows that short-term memory and long-term memory involve separate mechanisms and are independently processed. Other treatments, however, influence both memory types similarly, suggesting links between both at the receptor and at the post-receptor level, which should not be surprising as they both deal with nearly the same sensorimotor representations. This review examines recent advances in short- and long-term memory mechanisms based on the effect of intra-hippocampal infusion of drugs acting upon neurotransmitter and signal transduction systems on both memory types.