[Giant tumor from the nerve sheath]. / Tumor gigante de vaina neural.

A schwannoma is a benign nerve sheath tumor derived from Schwann cells. They are usually small and solitary tumors more frequently localized in cranial nerves and the spinal cord and rarely in the limbs. Some cases have been reported involving extremities (mainly the upper ones) but with a small size. Cases of big size schwannomas unrelated to a neurofibromatosis are very rare. We report the case of a 25 year old patient, with a giant schwannoma which invaded the ischiatic region reaching the triceps surae.

El schwannoma es un tumor benigno derivado de la vaina neural de las células de Schwann. Habitualmente suele ser pequeño y solitario, siendo más frecuente en los pares craneales y en la médula espinal, aunque menos frecuente en las extremidades. Se han descrito casos de aparición en las extremidades (principalmente superiores). Son muy raros los casos de schwannomas de gran tamaño sin relación con la neurofibromatosis. Presentamos a una paciente de 25 años de edad, con un schwannoma gigante que invadía desde la región isquiática al tríceps sural.

Predicting soil CO2 emissions and sinks due to soil management factors of Brachiaria decumbens pastures using Tier 2 IPCC Methodology / Predicción de emisiones y sumideros de CO2 del suelo debido a factores de manejo del suelo de Brachiaria decumbens usando Tier 2 metodología IPCC

ABSTRACT Soil carbon sequestration refers to the process of transferring carbon dioxide (CO2) from the atmosphere into the soil. The objective of this research was to do a simulation of how soil management factors in pastures can contribute to mitigate climate change by reducing soil CO2-eq emissions due to increases of soil organic carbon.In livestock systems of Cumaral (Meta), Colombia, IPCC Tier 2 methodology was used to compare changes in soils C stocks under (a) two pasture types: Brachiaria decumbens grass pastures (B1) and Brachiaria decumbens grass pastures associated with Pueraria phaseloides legume (B2); (b) four increasing doses of CaCO?: 0, 1.1, 2.2, 3.3 tons ha-1; (c) three sources of N, P, K fertilizers: 100 kg ha-1 Urea, 200 kg ha-1 Triple Superphosphate and 100 kg ha-1 Potassium Chloride. The statistical design was a randomized complete block in factorial arrangement 2 x 4 x 3. Tukey test indicated that the inclusion of kudzú in B. decumbens pasture (B2), 2.2 and 3.3 tons CaCO3 ha-1 in both pastures, and the fertilization of B1 with Urea and B2 with Triple Superphosphate presented a greater benefit in soil C accumulation and CO2-eq emissions neutralization. Adittional cluster analysis showed that B2 liming with higher lime doses regardless of the type of fertilizer used presented major soil C stored grouped in Cluster 1. We concluded that these soil management factors should be feasible to implement in pastures, that can help offset the negative effects of global climate change on livestock systems at tropical zones.

RESUMEN El secuestro de carbono en el suelo se refiere al proceso de transferencia de dióxido de carbono (CO2) de la atmósfera al suelo. El objetivo de esta investigación fue hacer una simulación de cómo los factores de manejo del suelo en pasturas, pueden contribuir a mitigar el cambio climático al reducir las emisiones de CO2-eq del suelo debido a los aumentos de acumulación de carbono orgánico en el suelo. En sistemas ganaderos de Cumaral (Meta), Colombia, se utilizó la metodología Tier 2 del Panel Intergubernamental sobre Cambio Climático (IPCC) para comparar los cambios en las existencias de C del suelo en (a) dos tipos de pasturas: pasturas de pasto Brachiaria decumbens (Bl) y pasturas del pasto Brachiaria decumbens asociadas con leguminosa de Pueraria phaseloi-des (B2); cuatro dosis crecientes de CaCO?: 0, l.l, 2.2, 3.3 tons ha1; y (c) tres fuentes de fertiliantes N, P, K: 100 kg ha-1 Urea, 200 kg ha-1 Superfosfato triple y 100 kg ha-1 Cloruro de potasio. El diseño estadístico fue un bloques completos al azar en arreglo factorial 2 x 4 x 3. El test de Tukey indicó que la inclusión de la leguminosa en la pastura (B2), la aplicación de 2.2 y 3.3 tons CaCO3 ha-1 en ambas pasturas y la fertilización de B1 con Urea y de B2 con Superfosfato triple presentaron un mayor beneficio en la acumulación de C del suelo y la neutralización de las emisiones de CO2-eq. El análisis de cluster adicional mostró que B2 encalada con más altas dosis de cal indistintamente del tipo de fertilizante usado presentaron mayor almacenamiento de C del suelo agrupados en el Cluster 1. Nosotros concluimos que estos factores de manejo de suelos deberían ser factibles de implementar en pasturas, lo que puede ayudar a compensar los efectos negativos del cambio climático global en los sistemas ganaderos de zonas tropicales.

Graded contribution of retinal maturation to the development of oxygen-induced retinopathy in rats.

PURPOSE: Newborn rats exposed to hyperoxia during the first days of life have been shown to exhibit not only vasculopathy but also permanent changes in the structure and function of the retina. Given that the rat retina is immature at birth and that the maturation process continues until the opening of the eyes at 14 days of life, this study was conducted to investigate the susceptibility of the retina to oxygen toxicity as a function of the degree of retinal maturity reached at the time of oxygen exposure. METHODS: Newborn rats were exposed to hyperoxia during selected postnatal day intervals. Scotopic electroretinograms were recorded at 30 and 60 days of age, and retinal histology was obtained at the end of the study. RESULTS: There was a strong correlation between the duration of the hyperoxic event and the structural and functional consequences in the retina. However, the repercussions were significantly more profound when the exposure to oxygen occurred within the second week of life (6-14 days), compared with earlier (0-6 days) or later periods (14-28 days). CONCLUSIONS: The results strongly suggest that the structural and functional retinal changes secondary to postnatal hyperoxia are not only the direct consequence of exposure to high levels of oxygen (i.e., free radicals), but also are determined by the level of retinal maturity reached at the time of oxygen exposure. The results also indicate that the structural anomalies precede the functional impairments.

Comparison of the def index with Nyvad's caries diagnostic criteria in 3- and 4-year-old Colombian children.

PURPOSE: The aims of this research were to determine the epidemiological profile of dental caries in 3- and 4-year-old preschool children living in Bogotá, Colombia, and to compare two different caries indices--the standard def and Nyvad's new caries diagnostic criteria. METHODS: The children were screened by two calibrated examiners who first brushed the children's teeth and air dried them for 5 seconds before they were examined. The diagnostic criteria used were the standard def-t and def-s and the def-t and def-s of the new caries diagnostic system proposed by Nyvad. The chi-square test2 was used with a significance level of 5%. RESULTS: Prevalence of caries was 70% using the standard def-t criteria and 97% with the criteria proposed by Nyvad. The standard def-t and def-s were 3.3 and 5.7, respectively, and the def-t and def-s with the Nyvad citeria were 8.7 and 14.3, respectively. CONCLUSIONS: Prevalence of caries was high, indicating that the population studied had a high disease rate. The results obtained with the more detailed Nyvad new caries diagnostic criteria were higher than the ones obtained with the standard def-t index, both for teeth and surfaces.

Psychological study in children addicted to inhalation of volatile substances.

Deliberate inhalation of volatile substances is a common and harmful practice among young persons around the world. Psychological studies were performed in 40 children habituated to inhalation of volatile agents, with the aim to define the psychological profile of inhalers, particularly their reactions against frustration. A significant difference in the extrapunitive attitude (p less than 0.001) and in the reaction of ego-defense (p less than 0.02) was found in sniffers as compared with controls. Addicted children also showed inadequate handling of frustration, aggressive and defensive behaviours, and passive and irresponsible attitude when confronted with problems.

Behavioral, morphological and physiological correlates of diurnal and nocturnal vision in selected wading bird species.

We examined in selected wading bird species if diurnal or nocturnal foraging and the use of visual or tactile feeding strategies could be correlated with retinal structure and function. The selected species were the Yellow-crowned Night Heron (Nycticorax violaceus), a crepuscular and nocturnal forager, the Great Blue Heron (Ardea herodias), a mainly crepuscular, but also diurnal and nocturnal feeder, the Roseate Spoonbill (Ajaia ajaja), a mainly crepuscular feeder which forages more at night than during the day, the Cattle (Bubulcus ibis) and Tricolored (Egretta tricolor) egrets and the American White Ibis (Eudocimus ruber) which forage only during daytime. Herons and egrets are visual foragers; ibises and spoonbills are tactile feeders. Electroretinograms were obtained from anesthetized birds in photopic and scotopic conditions to a wide range of light intensities, following which the retinae were processed for histological analysis. Based on rod densities and rods:cones ratios, nocturnal vision capability is greater in the Yellow-crowned Night Heron, followed by the Great Blue Heron and the spoonbill, then by the egrets and the ibis. Visual feeders that forage near dawn or dusk or at night have a higher rods:cones ratio, and consequently a greater night vision capability, than visual feeding species which forage only during daytime. Visual nocturnal feeders have a night vision capability greater than tactile diurnal as well as tactile nocturnal feeders. However, based on maximum scotopic b-wave amplitudes, all species studied have roughly comparable night vision capability. The factor that best discriminates between wading bird species appears to be the daytime visual capabilities. Indeed, the diurnal ibis and egrets have similar cone densities, cones:rods ratios, and photopic a-wave amplitudes, values which are greater than those measured in the two nocturnally active heron species.

Diurnal and nocturnal visual capabilities in shorebirds as a function of their feeding strategies.

Some shorebird species forage with the same feeding strategy at night and during daytime, e.g. visual pecking in the Wilson's Plover (Charadrius wilsonia) or tactile probing in the Short-billed Dowitcher (Limnodromus griseus). The American Woodcock (Scolopax minor) uses tactile probing, by day and by night, but sometimes pecks for insects during daytime. The Black-winged Stilt (Himantopus himantopus) is a visual pecker, both by day and by night, and sometimes forages tactilely on windy (agitated water surface) moonless nights. Territorial Willets (Catoptrophorus semipalmatus) are visual peckers during daylight and on moonlight conditions but switch to tactile feeding under lower light conditions. It could be postulated that some shorebird species would switch from visual feeding during daytime to tactile foraging at night because they have poor night vision compared to species that are always sight foragers irrespective of the time of the day. This issue was examined by comparing retinal structure and function in the above species. Electroretinograms (ERGs) were obtained at different light intensities from anesthetized birds, and the retinae were processed for histological observations. Based on ERGs, retinal sensitivity, and rod:cone ratios, both plovers and stilts are well adapted for nocturnal vision. Although they have low rod density compared to that of stilts and plovers, Willets and woodcocks have a scotopic retinal sensitivity similar to that of stilts and plovers but rank midway between plovers and dowitchers for the b-wave amplitude. Dowitchers have the lowest scotopic b-wave amplitude and retinal sensitivity and appear the least well adapted for night vision. Based on photopic ERGs and cone densities, although stilts, Willets and dowitchers appear as well adapted for daytime vision, plovers occupy the last rank of all species examined. Compared to the nighttime tactile feeders and those that switch from daytime visual pecking to tactile feeding at night, nighttime sight feeders have a superior rod function and, consequently, potentially superior nocturnal visual capabilities.

Retinal morphology and electrophysiology of two caprimulgiformes birds: the cave-living and nocturnal oilbird (Steatornis caripensis), and the crepuscularly and nocturnally foraging common pauraque (Nyctidromus albicollis).

Oilbirds (Steatornis caripensis) breed in the total darkness of caves and forage at night on fruits. Common pauraques (Nyctidromus albicollis) are crepuscular and nocturnal foragers on flying insects. We examined if their retinal structure and function can be correlated with their types and periods of activity. Electroretinograms (ERGs) were obtained from anesthetized birds in photopic and scotopic conditions to a wide range of light intensities, following which the retinas were processed for histological analysis. Retinal sensitivity is higher in oilbirds than in common pauraques. Under scotopic conditions with maximum flash luminance, the average (+/- 95% CI) b-wave amplitude of oilbirds is double that of common pauraques (500.4 +/- 49.8 and 245.4 +/- 40.9 microV, respectively) but, under photopic conditions, the results are the reverse (common pauraque: 69.4 +/- 18.1; oilbird: 23.0 +/- 4.4 microV). On the other hand, the retina of both species is highly rod-dominated, but rods are highly more numerous in oilbirds than in common pauraques (rods:cones ratio: 123:1 and 5:1, respectively). In oilbirds, rods are largely thinner and their outer segments are 1.0 microm in diameter and 18.6 microm in length. They are distributed over various levels in the photoreceptor layers, an arrangement known for deep-sea fishes, but so far unknown for birds. In common pauraques, rods are patchily distributed and their outer segments are 4.0 microm in diameter and 53 microm in length. The oilbirds rod thinness allows more rods per area unit, and thus to catch more photons per area unit under darkness, while the low cone number suggests that the species has poor daytime vision, which concurs with the species cavernicolous daytime habits. The lower rod number of common pauraques, compared to oilbirds, appears counterbalanced by their patchiness and longer and thicker outer segments to provide high retinal sensitivity. In addition, common pauraques also have a tapetum. These features, combined with a higher proportion of cones, show that common pauraques are well equipped for crepuscular and nocturnal foraging on flying insects in an open environment.

Persistent functional and structural retinal anomalies in newborn rats exposed to hyperoxia.

Previous studies have shown that newborn rats exposed postnatally to hyperoxia will develop a permanent impairment of the retinal function as determined with the electroretinogram (ERG). The purpose of our study was to examine whether postnatal hyperoxia equally alters the light- and dark-adapted ERGs and oscillatory potentials (OPs) as well as leads to permanent structural modification of the retina. During the first 14 days of life, cohorts of Sprague-Dawley rats were exposed to a hyperoxic environment, and ERGs were recorded at mean ages of approximately 25 and 55 days. Our results indicate that both light- and dark-adapted ERGs and OPs are already significantly altered within a few days following exposure to hyperoxia. None of the ERG and (or) OP parameters, with the exception of the a-wave, returned to normal values by 55 days of age. In fact some dark-adapted OPs were completely abolished following postnatal O2 exposure. Histological analysis revealed that the retina of rats exposed to hyperoxia failed to develop an outer plexiform layer and had a reduced count of horizontal cells, consistent with the permanent postreceptoral anomalies seen in the ERG responses. Our results suggest that postnatal hyperoxia causes a generalized retinal disorder leading to permanent structural modifications of the retinal cytoarchitecture and lasting anomalies of the rod and cone functions.

Factores psicogenicos en el sindrome de amenorrea-galactorrea. / Psychogenic factors in amenorrhea-galatorrhea syndrome

Se ha informado que hay pacientes con sindrome de amenorrea-galactorrea en las que se encuentran alteraciones emocionales que en alguna forma pudieran provocar o asociarse a hiperprolactinemia cronica, por lo que se estudiaron 15 pacientes a quienes se aplico una bateria de pruebas psicologicas compuestas por los siguientes instrumentos:1) inventario multifasico de la personalidad, 2) prueba de Machover y 3) cedula de entrevista. Se encontro principalmente que siete de las 15 pacientes tenian problemas depresivos y ocho de ellas tenian personalidad esquizoide. Los datos de la entrevista revelaron que 12 pacientes fueron abandonados en la ninez y 13 tuvieron problemas de relacion interpersonal con la madre. Se concluye que no obstante la demostracion de la asociacion psicoendocrina ya senalada por otros investigadores no es posible por ahora establecer una relacion causa efecto

Evaluación del dolor postoperatorio en cirugía de hemiabdomen superior bajo cinco esquemas de analgesia / Evaluation of postoperatory pain in upper hemiabdominal surgery under 5 schemes of analgesia

Sesenta y nueve pacientes ASA I y II sometidos a cirugía de hemiabdomen superior, fueron asignados al azar a uno de 5 esquemas analgésicos, iniciados en la inducción anestésica y mantenidos durante 24 horas: I: ketoprofeno 100 mg IV c/8 horas. II: fentanyl 4 µg/kg en bolo + infusión de 1 µg/kg-1/h-1. III: morfina 4 mg vía peridural lumbar. IV: metadona 0,1 mg/kg IM c/8 h. V: morfina 0,1 mg/kg en bolo + infusión de 10 µg/kg-1/h-1. Fueron evaluados por un observador entrenado que desconocía el esquema utilizado, a través de: 1) Escala visual análoga (EVA); 2) Escala de valoración verbal (EVV) en reposo; 3) Fascie del paciente en reposo y en movimiento; 4) EVV retrospectiva; 5) Número de analgésicos adicionales; 6) Aceptabilidad al método. Las evaluaciones se hicieron a las 2, 4, 6, 12, 24, 36, 48 horas de iniciado el esquema, consignándose además: FR, PA, FC, presencia de náuseas, vómitos, retención urinaria, prurito y grado de sedación. Se controló gases en sangre arterial a las 2, 12 y 24 horas. Se hizo ANOVA + t-Test o Chi cuadrado, según correspondía. Todos los grupos fueron comparables. Hubo mejor analgesia en los grupos II, III y IV, habiendo diferencia significativa para el grupo II. Todos lod grupos requirieron analgésicos adicionales, siendo el promedio menor en el grupo II. No hubo diferencia intergrupo en cuanto a náuseas, vómitos y retención urinaria. La aceptabilidad al método fue buena. La PaO2 fue similar en todos los grupos. No hubo retención de CO2 en ningún grupo, siendo la PaCO2 significativamente menor en el grupo I. Hubo alivio del dolor con los 5 esquemas utilizados, siendo mejor el esquema II. Tuvimos buena aceptación al método y no hubo complicaciones inherentes a él