Machine learning outperforms clinical experts in classification of hip fractures.

Hip fractures are a major cause of morbidity and mortality in the elderly, and incur high health and social care costs. Given projected population ageing, the number of incident hip fractures is predicted to increase globally. As fracture classification strongly determines the chosen surgical treatment, differences in fracture classification influence patient outcomes and treatment costs. We aimed to create a machine learning method for identifying and classifying hip fractures, and to compare its performance to experienced human observers. We used 3659 hip radiographs, classified by at least two expert clinicians. The machine learning method was able to classify hip fractures with 19% greater accuracy than humans, achieving overall accuracy of 92%.

The density of anthropogenic features explains seasonal and behaviour-based functional responses in selection of linear features by a social predator.

Anthropogenic linear features facilitate access and travel efficiency for predators, and can influence predator distribution and encounter rates with prey. We used GPS collar data from eight wolf packs and characteristics of seismic lines to investigate whether ease-of-travel or access to areas presumed to be preferred by prey best explained seasonal selection patterns of wolves near seismic lines, and whether the density of anthropogenic features led to functional responses in habitat selection. At a broad scale, wolves showed evidence of habitat-driven functional responses by exhibiting greater selection for areas near low-vegetation height seismic lines in areas with low densities of anthropogenic features. We highlight the importance of considering landscape heterogeneity and habitat characteristics, and the functional response in habitat selection when investigating seasonal behaviour-based selection patterns. Our results support behaviour in line with search for primary prey during summer and fall, and ease-of-travel during spring, while patterns of selection during winter aligned best with ease-of-travel for the less-industrialized foothills landscape, and with search for primary prey in the more-industrialized boreal landscape. These results highlight that time-sensitive restoration actions on anthropogenic features can affect the probability of overlap between predators and threatened prey within different landscapes.

EcoAnthromes of Alberta: An example of disturbance-informed ecological regionalization using remote sensing.

Humans influence ecosystems on magnitudes that often exceed that of natural forces such as climate and geology; however, frameworks rarely include anthropogenic disturbance when delineating unique ecological regions. A critical step toward understanding, managing and monitoring human-altered ecosystems is to incorporate disturbance into ecological regionalizations. Furthermore, quantitative regionalization approaches are desirable to provide cost-effective, repeatable and statistically sound stratification for environmental monitoring. We applied a two-stage multivariate clustering technique to identify 'EcoAnthromes' across a large area - the province of Alberta, Canada - at 30 m spatial resolution, and using primarily remotely sensed inputs. The EcoAnthrome clusters represent regions with unique ecological characteristics based on a combination of natural ecological potential (e.g., climatic and edaphic factors) and disturbance, both natural and anthropogenic. Compared to existing expert-derived Natural Subregions in Alberta, the model-based EcoAnthromes showed greater class separation and explained more variance for an assortment of variables related to land cover, disturbance and species intactness. The EcoAnthromes successfully separated important ecological regions that are defined by complex assemblages of topography, climate and disturbance, such as gravel-bed river valleys, boreal forests, grasslands, post-fire recovery areas and highly disturbed agricultural, industrial and urban landscapes. In addition to presenting a flexible method for EcoAnthrome regionalization, we group and describe the EcoAnthromes created for Alberta and discuss how they can complement expert-derived regionalizations to aid in environmental management efforts, such as species recovery planning and monitoring for threatened species.

Motorized Activity on Legacy Seismic Lines: A Predictive Modeling Approach to Prioritize Restoration Efforts.

Natural regeneration of seismic lines, cleared for hydrocarbon exploration, is slow and often hindered by vegetation damage, soil compaction, and motorized human activity. There is an extensive network of seismic lines in western Canada which is known to impact forest ecosystems, and seismic lines have been linked to declines in woodland caribou (Rangifer tarandus caribou). Seismic line restoration is costly, but necessary for caribou conservation to reduce cumulative disturbance. Understanding where motorized activity may be impeding regeneration of seismic lines will aid in prioritizing restoration. Our study area in west-central Alberta, encompassed five caribou ranges where restoration is required under federal species at risk recovery strategies, hence prioritizing seismic lines for restoration is of immediate conservation value. To understand patterns of motorized activity on seismic lines, we evaluated five a priori hypotheses using a predictive modeling framework and Geographic Information System variables across three landscapes in the foothills and northern boreal regions of Alberta. In the northern boreal landscape, motorized activity was most common in dry areas with a large industrial footprint. In highly disturbed areas of the foothills, motorized activity on seismic lines increased with low vegetation heights, relatively dry soils, and further from forest cutblocks, while in less disturbed areas of the foothills, motorized activity on seismic lines decreased proportional to seismic line density, slope steepness, and white-tailed deer abundance, and increased proportional with distance to roads. We generated predictive maps of high motorized activity, identifying 21,777 km of seismic lines where active restoration could expedite forest regeneration.

Isotopic Incorporation and the Effects of Fasting and Dietary Lipid Content on Isotopic Discrimination in Large Carnivorous Mammals.

There has been considerable emphasis on understanding isotopic discrimination for diet estimation in omnivores. However, discrimination may differ for carnivores, particularly species that consume lipid-rich diets. Here, we examined the potential implications of several factors when using stable isotopes to estimate the diets of bears, which can consume lipid-rich diets and, alternatively, fast for weeks to months. We conducted feeding trials with captive brown bears (Ursus arctos) and polar bears (Ursus maritimus). As dietary lipid content increased to ∼90%, we observed increasing differences between blood plasma and diets that had not been lipid extracted (∆(13)Ctissue-bulk diet) and slightly decreasing differences between plasma δ(13)C and lipid-extracted diet. Plasma Δ(15)Ntissue-bulk diet increased with increasing protein content for the four polar bears in this study and data for other mammals from previous studies that were fed purely carnivorous diets. Four adult and four yearling brown bears that fasted 120 d had plasma δ(15)N values that changed by <±2‰. Fasting bears exhibited no trend in plasma δ(13)C. Isotopic incorporation in red blood cells and whole blood was ≥6 mo in subadult and adult bears, which is considerably longer than previously measured in younger and smaller black bears (Ursus americanus). Our results suggest that short-term fasting in carnivores has minimal effects on δ(13)C and δ(15)N discrimination between predators and their prey but that dietary lipid content is an important factor directly affecting δ(13)C discrimination and indirectly affecting δ(15)N discrimination via the inverse relationship with dietary protein content.

Self expanding wall stents in malignant colorectal cancer: is complete obstruction a contraindication to stent placement?

OBJECTIVE: Technical failures have previously been associated with complete clinical obstruction and complete block to the retrograde flow of gastrograffin is considered by some to be a contraindication to the procedure. We report on the technical and clinical success rates of self-expanding metallic stents (SEMS) in both complete and incomplete obstruction in a prospective series of malignant colorectal obstructions. METHOD: A prospective study of all patients undergoing attempted palliative and bridge to surgery SEMS placement for malignant colorectal obstruction over a 7-year period (April 1999-October 2006) was undertaken. RESULTS: Seventy-two patients (49 males) with a mean age of 71 years (range 49-98) were included. Technical success was achieved in 27 of 32 patients (84%) with complete obstruction and 33 of 36 patients (92%) with incomplete obstruction, P < 0.46, Fishers exact test. Clinical success was achieved in 17 of 26 patients (65%) with complete obstruction and 24 of 33 patients (73%) with incomplete obstruction, P < 0.58, Fishers exact test. Although placed correctly in 89% cases, relief of symptoms occurred in only 71%, P = 0.002, matched pairs test. There were two colonic perforations in the series with one procedure related death. CONCLUSION: Placement of SEMS for obstructing colorectal cancer is technically successful in a high proportion of cases. Complete radiological obstruction is not a contraindication to stent placement. The relief of obstructive symptoms following successful placement of a wall stent is less predictable.

Thyroid transcription factor 1 in pulmonary adenocarcinoma.

AIMS: To discover whether variations in thyroid transcription factor 1 (TTF-1) staining in different subtypes and patterns of pulmonary adenocarcinoma are related to the putative origin of the tumour. In addition, to confirm the specificity of TTF-1 for pulmonary (as opposed to other sites) adenocarcinoma, to examine the possible prognostic relevance of TTF-1 positivity in lung cancer, and to review this laboratory's experience of TTF-1 in diagnostic practice. MATERIALS/METHODS: In total, 128 primary lung adenocarcinomas, 106 primary non-pulmonary adenocarcinomas, and 37 pulmonary non-adenocarcinoma tumours were studied. In addition, 100 cases where TTF-1 was used in routine surgical pathology practice were investigated. Immunoperoxidase staining was performed on formalin fixed, paraffin wax embedded sections using anti-TTF-1 antibody. Staining was evaluated semiquantitatively using the frequency and intensity of nuclear positivity. RESULTS: None of the 106 non-pulmonary adenocarcinomas expressed TTF-1 and only three of the 37 non-adenocarcinoma lung cancers, all neuroendocrine carcinomas, were positive. Of the pulmonary adenocarcinomas, 75% were strongly positive for TTF-1. Mucinous (two of six) and poorly differentiated adenocarcinomas (four of 10) were less likely to stain. Of the peripheral adenocarcinomas, 33 of 37 were positive, whereas only seven of 14 of those of bronchial origin stained strongly. Atypical adenomatous hyperplasia strongly expressed TTF-1. No "false positives" were encountered in the 100 routine diagnostic cases. CONCLUSION: Positive TTF-1 staining is useful in the differential diagnosis of pulmonary adenocarcinomas. TTF-1 may be a lineage marker for tumours arising from the peripheral airway or alveolar epithelium and has no prognostic relevance.

Urachal adenocarcinoma in situ with pseudomyxoma peritonei: a case report.

A 54 year old man presented with a six month history of abdominal pain. A computerised tomography scan showed a well defined intra-abdominal unilocular mass with a calcified wall just superior to the bladder. At laparotomy, pseudomyxoma peritonei was discovered, together with a midline abdominal mass adherent to the anterior abdominal wall originating from the fundus of the bladder. The specimen consisted of a cystic mass measuring 14 x 9.5 x 7 cm overall, which contained mucoid material. Histological examination revealed that the cyst was lined by mucinous epithelium, which in areas varied from having bland morphology to showing pronounced nuclear and architectural atypia. There was abundant extracellular mucin. The specimen was extensively sampled but there was no evidence of invasion. This tumour has many unusual features, namely: the absence of destructive invasion, association with pseudomyxoma peritonei, areas of dysplasia and cystadenoma, and stromal osseous metaplasia within the wall.

Drug-related deaths in Grampian, Scotland.

AIMS: To analyse the demographic data from fatalities arising directly from illicit drug abuse in the Grampian area and compare the findings with trends in drug seizures in Grampian to ascertain if these reflect the recorded deaths, and to attempt to identify a subgroup of the abusing population which might be at greater danger from overdose of controlled substances. METHODS: Cases in which the cause of death was directly attributed to illicit drugs from the beginning of January 1995 until the end of December 1999 were identified, and their epidemiological and toxicological data were analysed. The information regarding drug seizures was gained from Home Office publications for the same time period. RESULTS: One hundred and thirteen cases were retrieved consisting of 93 males and 20 females, aged 16 to 43 years (Median 25). The most commonly isolated substance was morphine followed by benzodiazepines. In 97 cases two or more drugs were involved with five cases showing positive toxicology for four or more drugs. Of the female deaths 75% fell into the 16-25 year age range. Drug seizures rose by 49% from 1995 to 1998 with both heroin and benzodiazepine seizures increasing by more than five fold in the same period. CONCLUSIONS: Deaths directly due to illicit drugs showed a significant increase over the study period and were concentrated in the young male population. The drug seizures increased but the extent of this was not mirrored in the deaths. A shift in emphasis to an older age group is also indicated; drug misuse educational programmes should continue to be targeted at all populations but information may also be targeted at the older age groups and at females under 25 years of age.

Leucine activates system A amino acid transport in L6 rat skeletal muscle cells.

In this study, we present evidence showing that leucine is involved in the upregulation of system A amino acid transport activity in the L6 rat skeletal muscle cell line. At leucine concentrations of > or = 0.05 mM, the uptake of N-methylamino-alpha-isobutyric acid (MeAIB), a paradigm system A substrate, was stimulated by up to 50%. Kinetic analysis revealed that this stimulation was a result of an increase in the maximal transport rate of MeAIB uptake, from 327 +/- 26 to 450 +/- 8 pmol.min-1.mg protein-1 after incubation of cells with leucine. No significant change in the concentration at which MeAIB transport was half maximal was observed. System A activation was biphasic, reaching an initial plateau after 3 h, with a second phase of activation being observed after 5 h. The initial activation of system A transport occurred by a mechanism distinct from that activated by insulin-like growth factor-I (IGF-I) (3 nM), since the effects of leucine and IGF-I were additive. This activation was not due to transstimulation, since 2-amino-2-norbornane-carboxylic acid, a specific system L substrate, did not stimulate system A. Leucine's keto acid, ketoisocaproic acid, prevented the activation of system A transport, whereas aminooxyacetate, a transaminase inhibitor, augmented the increase in system A activity by leucine. Both cycloheximide and actinomycin D inhibited the leucine-induced increase in MeAIB uptake. The present results indicate that leucine, or some cellular component regulated by it, is capable of stimulating system A transport through control of DNA transcription, possibly of a gene encoding either a repressor or enhancer molecule of system A or perhaps of the gene encoding system A itself.

Soft tissue radiography for wooden foreign bodies--a worthwhile exercise?

Radiographs were taken of various types of wood embedded in chicken legs. Wood is seen as a filling defect. Paint and increased water content reduce the negative shadow of wood. The results suggest that radiography is worthwhile in cases of suspected wooden foreign bodies.

The clinical comparison of skeletal imaging agents.

99-MTc-methylene diophosphonate from two manufacturers was compared with 99mTc-ethane hydroxy diphosphonate in a randomised trial to assess the relative blood clearances and the subsequent image quality. The 99mTc-methylene diphosphonate preparations were found to be superior with respect to both blood clearance and subjectively assessed image quality, particularly when the interval between injection and scanning was three hours. Bone/soft tissue ratios did not mirror the highly significant qualitative comparisons of image quality.