Lung cancer remains the malignancy with the highest mortality and second highest incidence in both men and women within the United States. Image-guided ablative therapies are safe and effective for localized control of unresectable liver, renal, bone, and lung tumors. Local ablative therapies have been shown to slow disease progression and prolong disease-free survival in patients who are not surgical candidates, either due to local extent of disease or medical comorbidities. Commonly encountered complications of percutaneous ablation of lung tumors include pneumothorax, pleural inflammation, pleural effusions, and pneumonia, which are usually easily managed. This review will discuss the merits of image-guided ablation in the treatment of lung tumors and the underlying mechanism, procedural techniques, clinical utility, toxicity, imaging of tumor response, and future developments, with a focus on radiofrequency ablation.
Life-threatening acute aortic syndrome includes aortic dissection, intramural hematoma (IMH) and penetrating atherosclerotic ulcer (PAU). PAU and IMH carry a greater risk for aortic rupture. They most commonly occur in the descending thoracic aorta and are rare in the ascending aorta. Early diagnosis and intervention is crucial. We present the case of a 72-year-old female with a PAU of the ascending aorta complicated by hemopericardium with tamponade as well as IMH, successfully treated after rapid diagnosis and intervention, followed by a brief literature review.
Around the globe, coral reefs and other marine ecosystems are increasingly overfished. Conventionally, studies of fishing impacts have focused on the population size and dynamics of targeted stocks rather than the broader ecosystem-wide effects of harvesting. Using parrotfishes as an example, we show how coral reef fish populations respond to escalating fishing pressure across the Indian and Pacific Oceans. Based on these fish abundance data, we infer the potential impact on four key functional roles performed by parrotfishes. Rates of bioerosion and coral predation are highly sensitive to human activity, whereas grazing and sediment removal are resilient to fishing. Our results offer new insights into the vulnerability and resilience of coral reefs to the ever-growing human footprint. The depletion of fishes causes differential decline of key ecosystem functions, radically changing the dynamics of coral reefs and setting the stage for future ecological surprises.
Species assemblages vary in structure due to a wide variety of processes operating at ecological and much broader biogeographical scales. Cross-scale studies of assemblage structure are necessary to fully understand this variability. Here, we evaluate the abundance and occupancy patterns of hierarchically sampled coral assemblages in three habitats (reef flat, crest, and slope) and five regions (Indonesia, Papua New Guinea, the Solomon Islands, American Samoa, and the Society Islands) across the west-central Pacific Ocean. Specifically, we compare two alternative models that unify spatial variance and occupancy via the negative binomial distribution. The first assumes a power-law scaling between the mean and variance of abundance; the second assumes a quadratic variance-mean relationship and a constant abundance-invariant aggregation parameter. Surprisingly, the well-established power-law model performs worse than the model assuming abundance-invariant aggregation, for both variance-mean and occupancy-abundance relationships. We also find strong evidence for regional and habitat variation in these relationships and in the levels of aggregation estimated by the abundance-invariant aggregation model. Among habitats, corals on reef flats exhibited lower occupancy and higher levels of aggregation compared to reef crests and slopes. Among regions, low occupancy and high aggregation were most pronounced across all habitats in American Samoa. These patterns may be related to habitat and regional differences in disturbance and recovery processes. Our results suggest that the spatial scaling of abundance and occupancy is sensitive to processes operating among these habitats and at regional scales. However, the consistency of these relationships across species within assemblages suggests that a theoretical unification of spatial variance and occupancy patterns is indeed possible.
Patterns in the commonness and rarity of species are a fundamental characteristic of ecological assemblages; however, testing between alternative models for such patterns remains an important challenge. Conventional approaches to fitting or testing species abundance models often assume that species, not individuals, are the units that are sampled and that species abundances are independent of one another. Here we test three different models (the Poisson lognormal, the negative binomial, and the neutral, "zero-sum multinomial" [ZSM]) against species abundance distributions of Indo-Pacific corals and reef fishes. We derive and apply several alternative bootstrap analyses of model fit, each of which makes different assumptions about how species abundance data are sampled, and we assess the extent to which tests of model fit are sensitive to such assumptions. For all models, goodness of fit is remarkably consistent, regardless of whether one assumes that species or individuals are the units that are sampled or whether or not one assumes that species abundances are statistically independent of one another. However, goodness-of-fit estimates are approximately twice as precise and detect lack of model fit more frequently, when based on sampling of individuals, rather than species. Bootstrap analyses indicate that the Poisson lognormal distribution exhibits substantially better fit to species abundance patterns, consistent with model selection analyses. In particular, heterogeneity in species abundances (many rare and few highly abundant species) is too great to be captured by the ZSM model or the negative binomial model and is best explained by models that predict species abundance patterns that are much closer, but not identical, to the lognormal distribution. More broadly, our bootstrap analyses suggest that estimates of model fit are likely to be robust to assumptions about the statistical interdependence of species abundances, but that tests of model fit are more powerful when they assume sampling of individuals, rather than species. Such individual-based tests therefore may be able to identify lack of model fit where previous tests have been inconclusive.
While density dependence is a popular topic of research in population ecology, it has received much less attention at the community level. Using 27 years of data from Heron Island, on Australias Great Barrier Reef, we develop a matrix model of coral community dynamics that shows that community-level density dependence does occur and that it is fairly common, being found in 38% of the model parameters for which it was tested. In particular, colonization of free space (through either recruitment or growth of existing colonies) was nearly always density dependent. There were no consistent patterns in the results for mortality, persistence, or species interactions. Most transitions were found to be dependent on the cover of the incoming species group, with only a few dependent on that of the outgoing species group. In addition, few of the transitions representing species interactions were dependent on the amount of free space present, suggesting that the cover of other species does not influence encounters. When these results were combined into a model of community dynamics, it was found that density dependence resulted in a moderate increase in coral cover, which was spread over most species groups. The dynamics of the density-dependent assemblage were also a lot noisier than those of an assemblage without density dependence. Sensitivity analysis indicated that it was density dependence in the colonization probabilities, particularly of encrusting acroporids, bushy Acropora and staghorn Acropora, which had the main influence on the model, although persistence of free space was also important. Transitions representing mortality were only of minor importance, and those representing species interactions were of no importance.
The ecosystem goods and services provided by coral reefs are critical to the social and economic welfare of hundreds of millions of people, overwhelmingly in developing countries . Widespread reef degradation is severely eroding these goods and services, but the socioeconomic factors shaping the ways that societies use coral reefs are poorly understood . We examine relationships between human population density, a multidimensional index of socioeconomic development, reef complexity, and the condition of coral reef fish populations in five countries across the Indian Ocean. In fished sites, fish biomass was negatively related to human population density, but it was best explained by reef complexity and a U-shaped relationship with socioeconomic development. The biomass of reef fishes was four times lower at locations with intermediate levels of economic development than at locations with both low and high development. In contrast, average biomass inside fishery closures was three times higher than in fished sites and was not associated with socioeconomic development. Sustaining coral reef fisheries requires an integrated approach that uses tools such as protected areas to quickly build reef resources while also building capacities and capital in societies over longer time frames to address the complex underlying causes of reef degradation.
Radioembolization offers a novel way to treat the nonresectable, liver predominant hepatic malignancies with better tumor response and overall progression-free survival rates. Transarterial catheter-based radioembolization procedure involves the hepatic arterial administration of glass- or resin-based beta emitting Yttirum-90 microspheres. Safe delivery of the tumoricidal radiation dose requires careful angiogram planning and coil embolization to quantify lung shunting and prevent systemic toxicity, respectively. Diagnostic pretreatment angiogram also serves to identify the hepatic arterial variant anatomy and other coexisting pathologies that might require a different or alternative approach. We describe a complex case of celiac artery stenosis with tortuous pancreaticoduodenal arterial arcade precluding access to the right hepatic artery for performing radioembolization. Celiac artery stenting of the stenosis was performed to facilitate subsequent safe and successful Yttrium-90 microsphere radioembolization.
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