Effectiveness of Panama as an intercontinental land bridge for large mammals.

Habitat fragmentation is a primary driver of wildlife loss, and establishment of biological corridors is a common strategy to mitigate this problem. A flagship example is the Mesoamerican Biological Corridor (MBC), which aims to connect protected forest areas between Mexico and Panama to allow dispersal and gene flow of forest organisms. Because forests across Central America have continued to degrade, the functioning of the MBC has been questioned, but reliable estimates of species occurrence were unavailable. Large mammals are suitable indicators of forest functioning, so we assessed their conservation status across the Isthmus of Panama, the narrowest section of the MBC. We used large-scale camera-trap surveys and hierarchical multispecies occupancy models in a Bayesian framework to estimate the occupancy of 9 medium to large mammals and developed an occupancy-weighted connectivity metric to evaluate species-specific functional connectivity. White-lipped peccary (Tayassu pecari), jaguar (Panthera onca), giant anteater (Myrmecophaga tridactyla), white-tailed deer (Odocoileus virginianus), and tapir (Tapirus bairdii) had low expected occupancy along the MBC in Panama. Puma (Puma concolor), red brocket deer (Mazama temama), ocelot (Leopardus pardalis), and collared peccary (Pecari tajacu), which are more adaptable, had higher occupancy, even in areas with low forest cover near infrastructure. However, the majority of species were subject to ≥1 gap that was larger than their known dispersal distances, suggesting poor connectivity along the MBC in Panama. Based on our results, forests in Darien, Donoso-Santa Fe, and La Amistad International Park are critical for survival of large terrestrial mammals in Panama and 2 areas need restoration.

Efectividad de Panamá como un Puente Terrestre Intercontinental para Mamíferos Mayores Resumen La fragmentación del hábitat es un causante primario de la pérdida de biodiversidad, y el establecimiento de corredores biológicos es una estrategia común para mitigar este problema. El Corredor Biológico Mesoamericano (CBM) es un ejemplo notable que pretende conectar áreas boscosas protegidas entre México y Panamá para permitir la dispersión y flujo genético de organismos del bosque. El funcionamiento del CBM se ha cuestionado debido a que la degradación de los bosques en Centroamérica continúa, pero no se dispone de estimaciones confiables de la ocurrencia de especies. Los mamíferos grandes son indicadores adecuados del funcionamiento de los bosques tropicales Por lo tanto evaluamos su estado de conservación en el Istmo de Panamá, la sección más angosta del CBM. Utilizamos muestreos con cámaras trampa y modelos de ocupación para múltiples especies bajo un modelo Bayesiano para estimar la ocupación de 9 especies de mamíferos medianos a grandes, y desarrollamos una métrica de conectividad ponderada por la ocupación para evaluar la conectividad funcional para cada especie. El puerco de monte (Tayassu pecari), jaguar (Panthera onca), hormiguero gigante (Myrmecophaga tridactyla), venado cola blanca (Oidocoileus virginianus), y tapir (Tapirus bairdii) presentaron una ocupación baja en el CBM en Panamá. El puma (Puma concolor), venado corzo (Mazama temama), ocelote (Leopardus pardalis) y el saino (Pecari tajacu), que son más adaptables, presentaron mayor ocupación, aún en áreas con poca cobertura boscosa, cercanas a infraestructura. Sin embargo, la mayoría de las especies estuvo sujeta a ≥ 1 vacío que era mayor que sus distancias de dispersión conocidas, lo que sugiere una conectividad pobre a lo largo del CBM en Panamá. Basados en nuestros resultados, los bosques de Darién, Donoso-Santa Fé y el Parque Internacional La Amistad son críticos para la supervivencia de mamíferos terrestres grandes en Panamá mientras que 2 áreas requieren restauración.

Pseudohyperplastic prostatic adenocarcinoma in transurethral resections of the prostate.

Pseudohyperplastic prostatic adenocarcinoma is a recently described variety of adenocarcinoma that has been studied in core-needle biopsies and prostatectomy specimens. It is characterized by malignant glands that simulate benign hyperplastic glands with complex, medium to large-sized glands with papillary infoldings, luminal undulations, branching or cystic dilatations, and columnar cells with macronucleoli and nuclear enlargement. Our aim was to define frequency, tumor volume, and histologic features of pseudohyperplastic prostatic adenocarcinoma in transurethral resections of prostate. We studied 250 specimens from transurethral resections; 150 specimens were originally diagnosed as benign glandular hyperplasia, and 100 as conventional prostate adenocarcinomas. Of the 150 biopsies originally diagnosed as benign glandular hyperplasia, two (1.3%) had areas of pseudohyperplastic carcinoma. In both cases the neoplasm was limited to two chips and measured 3 and 4 mm in diameter, respectively. Both patients were asymptomatic 2 and 4 years after diagnosis. Of the 100 biopsies with adenocarcinoma, areas of pseudohyperplastic carcinoma were found in three cases. In the first two these areas were found in two fragments, and in the other case they were found in three chips, and measured 3, 4, and 6 mm, respectively. The clinical course in these cases was unfavorable, and two patients had metastasis. Main histologic findings included crowded glands (5/5), papillary projections (5/5), nuclear enlargement (5/5) macronucleoli (4/5) cystic glandular dilatation (4/5) straight luminal borders (4/5), pink amorphous secretions (4/5) nuclear hyperchromasia (3/5) and transition to small acinar pattern of adenocarcinoma (3/5). In conclusion, pseudohyperplastic prostate carcinoma is rare in transurethral resection specimens and is found in scarce chips. Frequency of false negative results in biopsies originally diagnosed as benign glandular hyperplasia was 1.3%. In biopsies diagnosed as carcinoma, this frequency was 3%. These patients had an adverse clinical course, apparently due to association with areas of conventional adenocarcinoma.