Plant species dispersed by Galapagos tortoises surf the wave of habitat suitability under anthropogenic climate change.

Native biodiversity on the Galapagos Archipelago is severely threatened by invasive alien species. On Santa Cruz Island, the abundance of introduced plant species is low in the arid lowlands of the Galapagos National Park, but increases with elevation into unprotected humid highlands. Two common alien plant species, guava (Psidium guajava) and passion fruit (Passiflora edulis) occur at higher elevations yet their seeds are dispersed into the lowlands by migrating Galapagos tortoises (Chelonoidis spp.). Tortoises transport large quantities of seeds over long distances into environments in which they have little or no chance of germination and survival under current climate conditions. However, climate change is projected to modify environmental conditions on Galapagos with unknown consequences for the distribution of native and introduced biodiversity. We quantified seed dispersal of guava and passion fruit in tortoise dung piles and the distribution of adult plants along two elevation gradients on Santa Cruz to assess current levels of 'wasted' seed dispersal. We computed species distribution models for both taxa under current and predicted future climate conditions. Assuming that tortoise migratory behaviour continues, current levels of "wasted" seed dispersal in lowlands were projected to decline dramatically in the future for guava but not for passion fruit. Tortoises will facilitate rapid range expansion for guava into lowland areas within the Galapagos National Park where this species is currently absent. Coupled with putative reduction in arid habitat for native species caused by climate change, tortoise driven guava invasion will pose a serious threat to local plant communities.

COMPARISON OF TOTAL LEUKOCYTE QUANTIFICATION METHODS IN FREE-LIVING GALAPAGOS TORTOISES (CHELONOIDIS SPP.).

Reptile hematologic data provide important health information for conservation efforts of vulnerable wildlife species such as the Galapagos tortoise (Chelonoidis spp.). Given the reported discrepancies between manual leukocyte counts for nonmammalian species, two manual leukocyte quantification methods, the Natt and Herrick's (NH) and the Eopette (EO), were compared to white blood cell (WBC) estimates from blood films of 42 free-living, clinically healthy, adult female Galapagos tortoises. To investigate the effects of delay in sample processing, estimated WBC counts and leukocyte differentials were compared for blood films prepared at time of collection under field conditions (T0) to blood films prepared from samples that were stored for 18-23 hr at 4°C in the laboratory (T1). Passing-Bablok regression analysis revealed no constant or proportional error between the NH and WBC estimates (T0 and T1) with slopes of 1.1 and 0.9, respectively. However both constant and proportional errors were present between EO and WBC estimates (T0 and T1) with slopes of 3.1 and 2.7, respectively. Bland Altman plots also showed agreement between the NH and WBC estimates where the points fell within the confidence-interval limit lines and were evenly distributed about the mean. In contrast, the EO and WBC estimate comparisons showed numerous points above the upper limit line, especially at higher concentrations. WBC estimates obtained from T0 and T1 films were in agreement, whereas heterophil and monocyte percentages based on differentials were not. Cell morphology and preservation were superior in T0 blood films because thrombocytes exhibited swelling after storage, becoming difficult to differentiate from lymphocytes. In this study, the highest quality and most reliable hematologic data in Galapagos tortoises were obtained by combining immediate blood film preparation with the NH leukocyte quantification method and a confirmatory WBC estimate from the blood film.

Vegetation dynamics drive segregation by body size in Galapagos tortoises migrating across altitudinal gradients.

Seasonal migration has evolved in many taxa as a response to predictable spatial and temporal variation in the environment. Individual traits, physiology and social state interact with environmental factors to increase the complexity of migratory systems. Despite a huge body of research, the ultimate causes of migration remain unclear. A relatively simple, tractable system - giant tortoises on Santa Cruz Island, Galapagos, was studied to elucidate the roles of environmental variation and individual traits in a partial migratory system. Specifically, we asked: (i) do Galapagos tortoises undergo long-distance seasonal migrations? (ii) is tortoise migration ultimately driven by gradients in forage quality or temperature; and (iii) how do sex and body size influence migration patterns? We recorded the daily locations of 17 GPS-tagged tortoises and walked a monthly survey along the altitudinal gradient to characterize the movements and distribution of tortoises of different sizes and sexes. Monthly temperature and rainfall data were obtained from weather stations deployed at various altitudes, and the Normalized Difference Vegetation Index was used as a proxy for forage quality. Analyses using net displacement or daily movement characteristics did not agree on assigning individuals as either migratory or non-migratory; however, both methods suggested that some individuals were migratory. Adult tortoises of both sexes move up and down an altitudinal gradient in response to changes in vegetation dynamics, not temperature. The largest tagged individuals all moved, whereas only some mid-sized individuals moved, and the smallest individuals never left lowland areas. The timing of movements varied with body size: large individuals moved upward (as lowland forage quality declined) earlier in the year than did mid-sized individuals, while the timing of downward movements was unrelated to body size and occurred as lowland vegetation productivity peaked. Giant tortoises are unlikely candidates for forage-driven migration as they are well buffered against environmental fluctuations by large body size and a slow metabolism. Notably the largest, and presumably most dominant, individuals were most likely to migrate. This characteristic and the lack of sex-based differences in movement behaviour distinguish Galapagos tortoise movement from previously described partial migratory systems.

Diagnóstico por ecografía de ruptura de implantes mamarios y otras complicaciones asociadas: artículo de revisión / Diagnosis by Ultrasound of Rupture of Mammary Implants and Other Associated Complications: Revision Article

El diagnóstico imaginológico de la ruptura del implante mamario es una consulta frecuente y un desafío diagnóstico. Los factores para su ocurrencia pueden relacionarse con el paciente ­razón de implantación, tipo de incisión, localización del implante, edad­ o con el mismo implante ­tipo, año de inserción, marca­. Dentro de las técnicas de imagen, la de mejor rendimiento diagnóstico es la resonancia magnética; sin embargo, en la mayoría de las ocasiones la herramienta de diagnóstico inicial es la ecografía. El aspecto por ultrasonido de un implante de silicona normal incluye la visualización de márgenes bien delimitados de la cubierta y el lumen de silicona homogéneo y anecoico. Existen diferentes signos imaginológicos en la ruptura intracapsular; los de mejor rendimiento son el aumento del tamaño del espacio entre la cápsula fibrosa y la cubierta externa del implante por ocupación de líquido extravasado, el aspecto complicado del lumen del implante dado por el signo de la escalera y los ecos internos de bajo nivel. En la ruptura extracapsular el signo más confiable es el signo de la tormenta de nieve. Otros signos, como el derrame periimplante y el contorno irregular del implante, no son confiables. Ambos tipos deben distinguirse del sangrado de silicona, un escape o trasudado de silicona a través de la cápsula sin una ruptura evidente u otro hallazgo asociado, debido a un cambio en la permeabilidad de la cubierta de la prótesis que aumenta con los años de uso de esta, siendo más frecuente entre 15 y 20 años.

The imaging diagnosis of the rupture of the mammary implant is a frequent consultation and a diagnostic challenge. The factors for occurrence can be related to the patient ­ reason for the implant, type of incision, location of the implant, age-or the implant itself-type, age of insertion, mark-. In the group of imaging techniques, the one with the best diagnostic performance is magnetic resonance; however, in most cases, the initial diagnosis tool is the ultrasound. The appearance of a normal silicone implant, through ultrasound, includes the visualization of well-defined margins of the cover, and the homogenous and anechoic silicone lumen. There are several imaging signs in the intracapsular rupture. The signs with the best performance are an increase in size of the space between the fibrous capsule and the external cover of the implant due to occupation of the extravasation liquid, as well as the complicated appearance of the implant lumen given by the staircase sign and the internal low-level echoes. The most reliable sign in the extra capsular rupture is the snowstorm sign. Other signs, such as peri-implant effusion and the irregular shape of the implant, are not reliable. Both types must be differentiated from silicone bleeding, which is a silicone exit or transudate through a capsule without evident rupture or another associated finding, due to a change in the permeability of the prosthesis cover, which increases its use over the years, most frequently in a span between 15 and 20 years.

Meduloblastoma cerebeloso bilateral en adultos: presentación de dos casos / Bilateral cerebellar medulloblastoma in adults: report of two cases

El medulobastoma hace parte de los tumores neuroectodérmicos primitivos. Es bien conocido que es la neoplasia maligna más frecuente del sistema nervioso central en la población pediátrica y el tumor primario más común de la fosa posterior en niños. A diferencia de lo anterior, su prevalencia es muy baja en la población adulta. Se han descrito signos imaginológicos del meduloblastoma en los niños, que consisten en masas de la línea media, por lo general bien definidas, que característicamente son hiperdensas en las imágenes de tomografía simple y que muestran un realce homogéneo e intenso con la administración del medio de contraste. Al contrario, en la población adulta, estas características varían y se encuentran masas hemisféricascerebelosas, por lo general mal definidas, que evidencian degeneración quística o necrótica y un realce menor con el medio de contraste, al ser comparadas con las de la población pediátrica. Tanto niños como adultos comparten su apariencia variable en las imágenes de resonancia, así como la afectación secundaria leptomeníngea y a distancia. Este artículo expone dos casos confirmados histopatológicamente de meduloblastomas bilaterales hemisféricos cerebelosos en dos pacientes adultos, con una presentación imaginológica atípica en los hemisferios cerebelosos aún no reportada en la literatura médica.

Digesta retention time in the Galápagos tortoise (Chelonoidis nigra).

The retention time of food in the digestive tract of animals has important implications for digestive physiology. Retention time impacts digestive efficiency and among herbivores affects plant-animal interactions including herbivory and seed dispersal. Poorly studied yet iconic Galápagos tortoises are large-bodied generalist herbivores and ecosystem engineers which migrate seasonally. Potentially variable digesta retention times due to strong seasonal and altitudinal temperature gradients may influence tortoise seed dispersal abilities and rates of herbivory. We fed captive adult tortoises living in semi-natural conditions on Galápagos with inert particles and seeds from locally available fruits to determine whether seed size and ambient temperature influenced retention time. Median retention time varied from 6 to 28days, with a mode of 12days. Seed size had no effect on any of our measures of retention time, but ambient temperature was inversely correlated with retention times. Long retention time facilitates long distance seed dispersal by Galápagos tortoises, which may improve effectiveness. The effect of temperature, which may double from hot lowlands to cold highlands through the seasonal cycle, on tortoise digesta retention time will strongly influence seed dispersal efficiency and may influence patterns of food selection and migration in this species.

Manifestaciones imaginológicas en la enfermedad sistémica por arañazo de gato: reporte de caso / Imaging manifestations in systemic cat scratch disease: case report

La enfermedad por arañazo de gato es una zoonosis causada por la bacteria Bartonella henselae, la cual se transmite al hombre por arañazos, mordeduras o exposición a la saliva de gatos. La enfermedad típicamente se manifiesta por una linfadenitis regional después de la inoculación bacteriana en la piel; sin embargo, existe una presentación sistémica atípica en el 5% al 10% de los pacientes, la cual genera síntomas inespecíficos, que obligan al radiólogo a mantener un alto índice de sospecha, con base en los hallazgos imaginológicos, para poder realizar una diagnóstico temprano y no invasivo; ello, teniendo en cuenta que la mayoría de los casos ocurre en la población pediátrica. A pesar de que en la mayoría de los casos los síntomas y hallazgos imaginológicos se resuelven espontáneamente, hay características específicas que requieren tratamiento antibiótico, tales como el compromiso sistémico, diagnosticado por imágenes. En este artículo se presenta un caso clínico de la Fundación Cardioinfantil, y se revisan aspectos epidemiológicos, manifestaciones clínicas y métodos de diagnóstico, así como hallazgos en las imágenes de ecografía, tomografía computarizada, resonancia magnética y medicina nuclear.

Cat scratch disease is a zoonosis caused by Bartonella henselae, which is transmitted by scratches, bites or exposition to cat´s saliva (1). The disease typically manifests with locallymphadenitis after bacterial inoculation in the skin, however, there is an atypical systemic presentation in 5 to 10% of patients, which causes unspecific symptoms. There are severalimaging findings that lead the radiologist to consider this diagnosis, in order to prevent an invasive procedure, especially if we consider that the majority of cases occur in the pediatricpopulation (2,3). Although in the majority of cases the symptoms and imaging findings resolve spontaneously, there are specific indications like the systemic form of the disease, which requires antibiotic treatment. In the present article we are exposing a case report from Fundación Cardioinfantil; we will review some epidemiologic aspects, clinical manifestations,diagnostic methods as well as imaging findings in Ultrasonography, Computed Tomography, Magnetic Resonance and Nuclear Medicine.

Toxoplasmosis cerebral congénita: reporte de un caso / Congenital toxoplasmosis: case report

La infección congénita por Toxoplasma gondii del sistema nervioso central es muy frecuente; así mismo son serias sus repercusiones clínicas y la afectación sobre el desarrollo neurológico del niño. El diagnóstico de esta entidad se puede sospechar con los hallazgos clínicos que, junto con el apoyo imaginológico y la confirmación serológica, permiten iniciar un tratamiento para disminuir el número de complicaciones de la población pediátrica afectada. En el artículo se exponen las fuentes de infección, sus manifestaciones clínicas, los hallazgos imaginológicos y la forma de confirmación serológica, con base en un caso clínico del Instituto de Ortopedia Infantil Roosevelt, de la ciudad de Bogotá, donde se tuvo la oportunidad de encontrar sus manifestaciones imaginológicas en la radiografía simple, la ecografía transfontanelar, la ecografía ocular y la tomografía de cráneo.

The central nervous system congenital infection by Toxoplasma gondii is very frequent, and its clinical and neurological implications can be serious in the children. The diagnosis of this disease can be suspected if the patient have the clinical symptoms and can be supported with some radiologic findings and confirmed by serological tests, in order to initiate a pharmacological treatment and diminish the complications of the pediatric population. This article exposes how humans can be infected, its clinical symptoms, serologic and imaging findings in conventional radiology, transcraneal and ocular ultrasonography and computed tomography, related to a case report in the Instituto de Ortopedia Infantil Roosevelt in Bogota, Colombia.

Litopedio. Diagnóstico por TC multicorte: reporte de un caso / Lithopedion diagnosed by ct multislice: case report

La incidencia de embarazos abdominales es baja; más aún, es inusual en la actualidad su retención prolongada con formación de litopedio. Reportamos un caso de litopedio como causa de dolor abdominal en una mujer multípara de 49 años de edad, el cual fue documentado por imágenes de TC multidetector y radiología convencional. Se realizó una laparotomía exploratoria programada, con la cual se extirpó el feto calcificado, con actitud en flexión, fijado a la trompa uterina derecha y adherido firmemente al epiplón.