Proximal row carpectomy in emergency

Proximal row carpectomy (PRC) is a well-accepted procedure for the treatment of early post-traumatic degenerative disease of the wrist. Much less frequently, PRC has been advocated as an emergency procedure for irreparable fracture-dislocation of the wrist. Our objective was to compare the results of PRC in patients having undergone this procedure in the two contexts. We conducted a retrospective analysis of the clinical and radiographic results of six patients treated by emergency PRC as compared to six patients who underwent elective PRC. The mean follow-up was 36 months. Both the patient's satisfaction and the grasp of the wrist joint were significantly better in patients who underwent PRC emergency as compared to those having undergone elective PRC. Quick DASH score, radiographic results, and return to work were also more favourable in these patients, but the difference between the two groups was not significant. This study confirms that PRC is a valuable salvage technique indicated in early posttraumatic wrist collapse. Moreover, when performed in emergency, the procedure shows even better subjective and objective results, allowing a majority of patients to return to their previous job.     

Hemisphere-scale differences in conifer evolutionary dynamics

Fundamental differences in the distribution of oceans and landmasses in the Northern and Southern Hemispheres potentially impact patterns of biological diversity in the two areas. The evolutionary history of conifers provides an opportunity to explore these dynamics, because the majority of extant conifer species belong to lineages that have been broadly confined to the Northern or Southern Hemisphere during the Cenozoic. Incorporating genetic information with a critical review of fossil evidence, we developed an age-calibrated phylogeny sampling ∼80% of living conifer species. Most extant conifer species diverged recently during the Neogene within clades that generally were established during the later Mesozoic, but lineages that diversified mainly in the Southern Hemisphere show a significantly older distribution of divergence ages than their counterparts in the Northern Hemisphere. Our tree topology and divergence times also are best fit by diversification models in which Northern Hemisphere conifer lineages have higher rates of species turnover than Southern Hemisphere lineages. The abundance of recent divergences in northern clades may reflect complex patterns of migration and range shifts during climatic cycles over the later Neogene leading to elevated rates of speciation and extinction, whereas the scattered persistence of mild, wetter habitats in the Southern Hemisphere may have favored the survival of older lineages.     

Automating Scoliosis Measurements in Radiographic Studies with Machine Learning: Comparing Artificial Intelligence and Clinical Reports

Journal of Digital Imaging - Scoliosis is a condition of abnormal lateral spinal curvature affecting an estimated 2 to 3% of the US population, or seven million people. The Cobb angle is the...     

Characteristics of the sequence effect in Parkinson's disease

The sequence effect (SE) in Parkinson's disease (PD) is progressive slowing of sequential movements. It is a feature of bradykinesia, but is separate from a general slowness without deterioration over time. It is commonly seen in PD, but its physiology is unclear. We measured general slowness and the SE separately with a computer‐based, modified Purdue pegboard in 11 patients with advanced PD. We conducted a placebo‐controlled, four‐way crossover study to learn whether levodopa and repetitive transcranial magnetic stimulation (rTMS) could improve general slowness or the SE. We also examined the correlation between the SE and clinical fatigue. Levodopa alone and rTMS alone improved general slowness, but rTMS showed no additive effect on levodopa. Levodopa alone, rTMS alone, and their combination did not alleviate the SE. There was no correlation between the SE and fatigue. This study suggests that dopaminergic dysfunction and abnormal motor cortex excitability are not the relevant mechanisms for the SE. Additionally, the SE is not a component of clinical fatigue. Further work is needed to establish the physiology and clinical relevance of the SE. © 2010 Movement Disorder Society.     

Intestinal epithelial wound healing assay in an epithelial–mesenchymal co-culture system

Rapid and efficient healing of epithelial damage is critical to the functional integrity of the small intestine. Epithelial repair is a complex process that has largely been studied in cultured epithelium but to a much lesser extent in mucosa. We describe a novel method for the study of wound healing using a co-culture system that combined an intestinal epithelial Caco-2/15 cell monolayer cultured on top of human intestinal myofibroblasts, which together formed a basement membrane-like structure that contained many of the major components found at the epithelial–mesenchymal interface in the human intestine. To investigate the mechanism of restitution, small lesions were generated in epithelial cell monolayers on plastic or in co-cultures without disturbing the underlying mesenchymal layer. Monitoring of wound healing showed that repair was more efficient in Caco-2/15–myofibroblast co-cultures than in Caco-2/15 monolayers and involved the deposition of basement membrane components. Functional experiments showed that the addition of type I collagen or human fibronectin to the culture medium significantly accelerated wound closure on epithelial cell co-cultures. This system may provide a new tool to investigate the mechanisms that regulate wound healing in the intestinal epithelium.     

Tissue segmentation in Monte Carlo treatment planning: a simulation study using dual-energy CT images.

PURPOSE: Tissue segmentation is an important step in Monte Carlo (MC) dose calculation and is often done uncritically. A new approach to tissue segmentation using dual-energy CT images is studied in this work. MATERIALS AND METHODS: A simple MC model of a CT scanner was built and CT images of phantoms with ten tissue-equivalent cylinders were simulated using soft and hard X-ray spectra. The Z and rho(e) of the cylinders were extracted using a formalism based on a parameterization of the linear attenuation coefficient. RESULTS: It was shown that in order to extract Z and rho(e) with a reasonable accuracy, hard X-ray beams have to be used for scanning. When an additional filtration of 9 mm of aluminium in the CT X-ray beam is used, beam hardening in high density materials is suppressed and the mean errors of the extraction of Z and rho(e) for 10 tissue-equivalent materials in a small tissue-equivalent phantom are 3.7% and 3.1%, respectively. CONCLUSIONS: MC simulations were used to show that the extraction of Z and rho(e) for a number of tissue-equivalent materials using dual-energy CT images is possible which improves tissue segmentation for Monte Carlo dose calculations, as demonstrated with a 250 kVp photon beam dose calculation.