The myogenic response in uremic hypertension

The myogenic response in uremic hypertension.BackgroundThe constriction of resistance arteries in response to an increase in transmural pressure, the myogenic response, is thought to be an important determinant of peripheral vascular resistance and therefore of arterial blood pressure. Since raised peripheral resistance is known to occur in uremic hypertension, abnormal myogenic constriction might be responsible. We sought to assess the myogenic response of resistance arteries from the subtotal nephrectomy rat model of uremic hypertension.MethodsUremic Wistar-Kyoto (WKYU) rats, and sham-operated normotensive (WKYC) and spontaneously hypertensive (SHRC) controls were studied in parallel. Skeletal muscle arteries were mounted on a pressure myograph and allowed to develop myogenic constriction. The active internal diameter was measured at increasing lumen pressures from 20 to 200 mm Hg. Vascular smooth muscle then was relaxed in a calcium free solution containing nitroprusside, and the passive internal diameter measured at the same pressure steps. The ratio of active to passive diameter at any given pressure was used to assess the myogenic response.ResultsMyogenic constriction was not increased in either WKYU or SHRC compared to WKYC at pressures up to 180 mm Hg.ConclusionsIncreased myogenic tone is not the cause of uremic hypertension

Status and needs for tank isolation system contingencies at the Oak Ridge National Laboratory

This document assesses the need for additional tank isolation systems and tooling at the Oak Ridge National Laboratory (ORNL). Locations for future operations at ORNL include the South and North Tank Farms and various Federal Facilities Agreement tanks. The goal of this report is to identify future needs for development of remote tools and systems to isolate inactive waste storage tanks

The Bristol Hip View: Its Role in the Diagnosis and Surgical Planning and Occult Fracture Diagnosis for Proximal Femoral Fractures

Aim. To evaluate whether a modified radiographic view of the femoral neck improves the diagnosis of occult proximal femoral. Materials and Methods. Prospective study of patients presenting with clinically suspected proximal femoral fractures or who underwent traditional plain radiographic views and the Bristol hip view (a 30-degree angled projection). Six blinded independent observers assessed the images for presence of a fracture, anatomical level, and displacement. Results. 166 consecutive patients presenting with the clinical diagnosis of a proximal femoral fracture, of which 61 sustained a fracture. Six of these were deemed occult due to negative plain and had proven fractures on subsequent cross-sectional imaging. The Bristol hip view demonstrated five of these six fractures. It performed better than the traditional lateral hip view to identify the injury. The Bristol hip view predicted correctly the fracture type and displacement in all cases and missed only one of the occult fractures. Conclusion. The Bristol hip view is more sensitive and clearer than a lateral projection for patients. It adds useful diagnostic information and performs better than the traditional views in occult fractures. Its use may prevent the need for further cross sectional imaging and subsequent surgical delay

Higher 30-day mortality associated with the use of intramedullary nails compared with sliding hip screws for the treatment of trochanteric hip fractures:a prospective national registry study

Aims The aim of this study was to investigate the association between the type of operation used to treat a trochanteric fracture of the hip and 30-day mortality. Patients and Methods Data on 82 990 patients from the National Hip Fracture Database were analyzed using generalized linear models with incremental case-mix adjustment for patient, non-surgical and surgical characteristics, and socioeconomic factors. Results The use of short and long intramedullary nails was associated with an increase in 30-day mortality (adjusted odds ratio (OR) 1.125, 95% confidence interval (CI) 1.040 to 1.218; p = 0.004) compared with the use of sliding hip screws (12.5% increase). If this were causative, it would represent 98 excess deaths over the four-year period of the study and one excess death would be caused by treating 112 patients with an intramedullary nail rather than a sliding hip screw. Conclusion There is a 12.5% increase in the risk of 30-day mortality associated with the use of an intramedullary nail compared with a sliding hip screw in the treatment of a trochanteric fractures of the hip.</p

Phylogeny and phylogenetic classification of the antbirds, ovenbirds, woodcreepers, and allies (Aves: Passeriformes: Infraorder Furnariides)

The infraorder Furnariides is a diverse group of suboscine passerine birds comprising a substantial component of the Neotropical avifauna. The included species encompass a broad array of morphologies and behaviours, making them appealing for evolutionary studies, but the size of the group (ca. 600 species) has limited well-sampled higher-level phylogenetic studies. Using DNA sequence data from the nuclear RAG-1 and RAG-2 exons, we undertook a phylogenetic analysis of the Furnariides sampling 124 (more than 88%) of the genera. Basal relationships among family-level taxa differed depending on phylogenetic method, but all topologies had little nodal support, mirroring the results from earlier studies in which discerning relationships at the base of the radiation was also difficult. In contrast, branch support for family-rank taxa and for many relationships within those clades was generally high. Our results support the Melanopareidae and Grallariidae as distinct from the Rhinocryptidae and Formicariidae, respectively. Within the Furnariides our data contradict some recent phylogenetic hypotheses and suggest that further study is needed to resolve these discrepancies. Of the few genera represented by multiple species, several were not monophyletic, indicating that additional systematic work remains within furnariine families and must include dense taxon sampling. We use this study as a basis for proposing a new phylogenetic classification for the group and in the process erect new family-group names for clades having high branch support across methods. © 2009 The Willi Hennig Society

Integrating Sequence Capture and Restriction Site-Associated DNA Sequencing to resolve Recent Radiations of Pelagic Seabirds

The diversification of modern birds has been shaped by a number of radiations. Rapid diversification events make reconstructing the evolutionary relationships among taxa challenging due to the convoluted effects of incomplete lineage sorting (ILS) and introgression. Phylogenomic datasets have the potential to detect patterns of phylogenetic incongruence, and to address their causes. However, the footprints of ILS and introgression on sequence data can vary between different phylogenomic markers at different phylogenetic scales depending on factors such as their evolutionary rates or their selection pressures. We show that combining phylogenomic markers that evolve at different rates, such as paired-end double-digest restriction site-associated DNA (PE-ddRAD) and ultraconserved elements (UCEs), allows a comprehensive exploration of the causes of phylogenetic discordance associated with short internodes at different timescales. We used thousands of UCE and PE-ddRAD markers to produce the first well-resolved phylogeny of shearwaters, a group of medium-sized pelagic seabirds that are among the most phylogenetically controversial and endangered bird groups. We found that phylogenomic conflict was mainly derived from high levels of ILS due to rapid speciation events. We also documented a case of introgression, despite the high philopatry of shearwaters to their breeding sites, which typically limits gene flow. We integrated state-of-the-art concatenated and coalescent-based approaches to expand on previous comparisons of UCE and RAD-Seq datasets for phylogenetics, divergence time estimation and inference of introgression, and we propose a strategy to optimise RAD-Seq data for phylogenetic analyses. Our results highlight the usefulness of combining phylogenomic markers evolving at different rates to understand the causes of phylogenetic discordance at different timescales

Lineage diversification and morphological evolution in a large-scale continental radiation: The neotropical ovenbirds and woodcreepers (aves: furnariidae)

Patterns of diversification in species-rich clades provide insight into the processes that generate biological diversity. We tested different models of lineage and phenotypic diversification in an exceptional continental radiation, the ovenbird family Furnariidae, using the most complete species-level phylogenetic hypothesis produced to date for a major avian clade (97% of 293 species). We found that the Furnariidae exhibit nearly constant rates of lineage accumulation but show evidence of constrained morphological evolution. This pattern of sustained high rates of speciation despite limitations on phenotypic evolution contrasts with the results of most previous studies of evolutionary radiations, which have found a pattern of decelerating diversity-dependent lineage accumulation coupled with decelerating or constrained phenotypic evolution. Our results suggest that lineage accumulation in tropical continental radiations may not be as limited by ecological opportunities as in temperate or island radiations. More studies examining patterns of both lineage and phenotypic diversification are needed to understand the often complex tempo and mode of evolutionary radiations on continents. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution

Palaeoceanographic changes in the late Pliocene promoted rapid diversification in pelagic seabirds

Aim: Palaeoceanographic changes can act as drivers of diversification and speciation, even in highly mobile marine organisms. Shearwaters are a group of globally distributed and highly mobile pelagic seabirds. Despite a recent well-resolved phylogeny, shearwaters have controversial species limits, and show periods of both slow and rapid diversification. Here, we explore the role of palaeoceanographic changes on shearwaters' diversification and speciation. We investigate shearwater biogeography and the evolution of a key phenotypic trait, body size, and we assess the validity of their current taxonomy