Registering a multisensor ensemble of images

Many registration scenarios involve aligning more than just two images. These image sets-called ensembles-are conventionally registered by choosing one image as a template, and every other image is registered to it. This pairwise approach is problematic because results depend on which image is chosen as the template. The issue is particularly acute for multisensor ensembles because different sensors create images with different features. Also, pairwise methods use only a fraction of the available data at a time. In this paper, we propose a maximum-likelihood clustering method that registers all the images in a multisensor ensemble simultaneously. Experiments involving rigid-body and affine transformations show that the clustering method is more robust and accurate than competing pairwise registration methods. Moreover, the clustering results can be used to form a rudimentary segmentation of the image ensemble.

Methods to identify postnatal depression in primary care: an integrated evidence synthesis and value of information analysis

OBJECTIVES

To provide an overview of methods to identify postnatal depression (PND) in primary care and to assess their validity, acceptability, clinical effectiveness and cost-effectiveness, to model estimates of cost, to assess whether any method meets UK National Screening Committee (NSC) criteria and to identify areas for future research.

DATA SOURCES

Searches of 20 electronic databases (including MEDLINE, CINAHL, PsycINFO, EMBASE, CENTRAL, DARE and CDSR), forward citation searching, personal communication with authors and searching of reference lists.

REVIEW METHODS

A generalised linear mixed model approach to the bivariate meta-analysis was undertaken for the validation review with quality assessment using QUADAS. Within the acceptability review, a textual narrative approach was employed to synthesise qualitative and quantitative research evidence. For the clinical and cost-effectiveness reviews methods outlined by the Centre for Reviews and Dissemination and the Cochrane Collaboration were followed. Probabilistic models were developed to estimate the costs associated with different identification strategies.

RESULTS

The Edinburgh Postnatal Depression Scale (EPDS) was the most frequently explored instrument across all of the reviews. In terms of test performance, postnatally the EPDS performed reasonably well: sensitivity ranged from 0.60 (specificity 0.97) to 0.96 (specificity 0.45) for major depression only; from 0.31 (specificity 0.99) to 0.91 (specificity 0.67) for major or minor depression; and from 0.38 (specificity 0.99) to 0.86 (specificity 0.87) for any psychiatric disorder. Evidence from the acceptability review indicated that, in the majority of studies, the EPDS was acceptable to women and health-care professionals when women were forewarned of the process, when the EPDS was administered in the home, with due attention to training, with empathetic skills of the health visitor and due consideration to positive responses to question 10 about self-harm. Suggestive evidence from the clinical effectiveness review indicated that use of the EPDS, compared with usual care, may lead to reductions in the number of women with depression scores above a threshold. In the absence of existing cost-effectiveness studies of PND identification strategies, a decision-analytic model was developed. The results of the base-case analysis suggested that use of formal identification strategies did not appear to represent value for money, based on conventional thresholds of cost-effectiveness used in the NHS. However, the scenarios considered demonstrated that this conclusion was primarily driven by the costs of false positives assumed in the base-case model.

CONCLUSIONS

In light of the results of our evidence synthesis and decision modelling we revisited the examination of PND screening against five of the NSC criteria. We found that the accepted criteria for a PND screening programme were not currently met. The evidence suggested that there is a simple, safe, precise and validated screening test, in principle a suitable cut-off level could be defined and that the test is acceptable to the population. Evidence surrounding clinical and cost-effectiveness of methods to identify PND is lacking. Further research should aim to identify the optimal identification strategy, in terms of key psychometric properties for postnatal populations. In particular, research comparing the performance of the Whooley and help questions, the EPDS and a generic depression measure would be informative. It would also be informative to identify the natural history of PND over time and to identify the clinical effectiveness of the most valid and acceptable method to identify postnatal depression. Further research within a randomised controlled trial would provide robust estimates of the clinical effectiveness.

Hypoglycaemia in Type 2 diabetes

The primary cause of hypoglycaemia in Type 2 diabetes is diabetes medication-in particular, those which raise insulin levels independently of blood glucose, such as sulphonylureas (SUs) and exogenous insulin. The risk of hypoglycaemia is increased in older patients, those with longer diabetes duration, lesser insulin reserve and perhaps in the drive for strict glycaemic control. Differing definitions, data collection methods, drug type/regimen and patient populations make comparing rates of hypoglycaemia difficult. It is clear that patients taking insulin have the highest rates of self-reported severe hypoglycaemia (25% in patients who have been taking insulin for > 5 years). SUs are associated with significantly lower rates of severe hypoglycaemia. However, large numbers of patients take SUs in the UK, and it is estimated that each year > 5000 patients will experience a severe event caused by their SU therapy which will require emergency intervention. Hypoglycaemia has substantial clinical impact, in terms of mortality, morbidity and quality of life. The cost implications of severe episodes-both direct hospital costs and indirect costs-are considerable: it is estimated that each hospital admission for severe hypoglycaemia costs around pound1000. Hypoglycaemia and fear of hypoglycaemia limit the ability of current diabetes medications to achieve and maintain optimal levels of glycaemic control. Newer therapies, which focus on the incretin axis, may carry a lower risk of hypoglycaemia. Their use, and more prudent use of older therapies with low risk of hypoglycaemia, may help patients achieve improved glucose control for longer, and reduce the risk of diabetic complications.

Breast tumor characteristics of BRCA1 and BRCA2 gene mutation carriers on MRI

The appearance of malignant lesions in BRCA1 and BRCA2 mutation carriers (BRCA-MCs) on mammography and magnetic resonance imaging (MRI) was evaluated. Thus, 29 BRCA-MCs with breast cancer were retrospectively evaluated and the results compared with an age, tumor size and tumor type matched control group of 29 sporadic breast cancer cases. Detection rates on both modalities were evaluated. Tumors were analyzed on morphology, density (mammography), enhancement pattern and kinetics (MRI). Overall detection was significantly better with MRI than with mammography (55/58 vs 44/57, P = 0.021). On mammography, lesions in the BRCA-MC group were significantly more described as rounded (12//19 vs 3/13, P = 0.036) and with sharp margins (9/19 vs 1/13, P = 0.024). On MRI lesions in the BRCA-MC group were significantly more described as rounded (16/27 vs 7/28, P = 0.010), with sharp margins (20/27 vs 7/28, P < 0.001) and with rim enhancement (7/27 vs 1/28, P = 0.025). No significant difference was found for enhancement kinetics (P = 0.667). Malignant lesions in BRCA-MC frequently have morphological characteristics commonly seen in benign lesions, like a rounded shape or sharp margins. This applies for both mammography and MRI. However the possibility of MRI to evaluate the enhancement pattern and kinetics enables the detection of characteristics suggestive for a malignancy.

Driving behavior under the influence of cannabis or cocaine

OBJECTIVE

The purpose of this study is first to describe perceptions of driving under the influence of cannabis or cocaine among clients in treatment and, second, to assess whether these perceptions are related to the frequency of driving under the influence of cannabis or cocaine.

METHODS

A questionnaire was administered to clients in treatment for abuse of either cocaine or cannabis, many of whom also had a problem with alcohol; additional groups of clients consisted of those in smoking cessation and gambling programs (N = 1021). Open-ended and close-ended questions were used to assess self-reported effects of cannabis or cocaine on driving and frequency of driving under the influence of cannabis, cocaine, or alcohol.

RESULTS

Two dimensions of driving behavior under the influence of cocaine or cannabis were found in both qualitative and quantitative analyses: 1) physical effects and 2) reckless styles of driving. Common physical effects for both drugs were heightened nervousness, greater alertness, and poorer concentration. In terms of driving behavior, cautious or normal driving was commonly reported for cannabis, whereas reckless or reduced driving ability was frequently reported for cocaine. When comparing negative physical effects and reckless style of driving with frequency of driving under the influence of cannabis or cocaine, increased negative physical effects from cannabis were inversely related to frequency of driving under the influence of cannabis (p = .001), but other relationships were not significant.

CONCLUSIONS

The findings indicate that both cannabis and cocaine have detrimental but different effects on driving. The negative physical effects of cannabis may reduce the likelihood of driving under the influence of cannabis.

Peptide binding at the GLP-1 receptor

The receptor for GLP-1 [glucagon-like peptide-1-(7-36)-amide] is a member of the 'Family B' of GPCRs (G-protein-coupled receptors) comprising an extracellular N-terminal domain containing six conserved cysteine residues (the N-domain) and a core domain (or J-domain) comprising the seven transmembrane helices and interconnecting loop regions. According to the two-domain model for peptide binding, the N-domain is primarily responsible for providing most of the peptide binding energy, whereas the core domain is responsible for binding the N-terminal region of the peptide agonists and transmitting the signal to the intracellular G-protein. Two interesting differences between the binding properties of two GLP-1 receptor agonists, GLP-1 and EX-4 (exendin-4), can be observed. First, while GLP-1 requires its full length to maintain high affinity, the eight N-terminal residues of EX-4 can be removed with little reduction in affinity. Secondly, EX-4 (but not GLP-1) can bind to the fully isolated N-domain of the receptor with an affinity matching that of the full-length receptor. In order to better understand these differences, we have studied the interaction between combinations of full-length or truncated ligands with full-length or truncated receptors.

The impact of Ontario's extended drinking hours on cross-border cities of Windsor and Detroit

PURPOSE

This study evaluated the cross-border safety impact of extended drinking hours from 1:00 to 2:00 a.m., in licensed establishments in Ontario, Canada.

METHODS

This study examined patterns in total and alcohol-related casualties in: (1) Windsor, Ontario, Canada compared to Detroit, Michigan, US with a 2:00 a.m. closing time, and (2) Ontario compared to Michigan for overall trends. The criterion outcome indicators were: (1) monthly motor vehicle casualties (major injuries and fatalities) for the city-regions of Windsor and Detroit and (2) Ontario and Michigan monthly motor vehicle fatalities occurring between 11:00 p.m. and 3:00 a.m. for 4 years pre- and 3 years post-policy change. In order to examine cross-border drinking consequences, data were disaggregated to assess trends of motor vehicle injury collisions involving vehicles with US licence plates and with US drivers aged 16-20 in the Windsor region; similarly trends were assessed for motor vehicle injury collisions involving vehicles with Ontario licence plates in the Detroit region.

RESULTS

The Windsor region total motor vehicle casualty data showed a non-significant pre-post increase, while the Detroit region showed a statistically significant decrease for total motor vehicle casualties. In the Windsor region, a significant increase was found for alcohol-related motor vehicle casualties after the drinking hours were extended. However, the Detroit region showed a statistically significant decrease in alcohol-related motor vehicle casualties concomitant with Ontario's drinking hour extension. No similar trends were found for the province of Ontario and the state of Michigan as a whole. Moreover, a significant decrease was found for injury collisions involving vehicles with Ontario licence plates in the Detroit region but no similar pattern was found for injury collisions involving vehicles with US licence plates and with 16-20-year-old US drivers in the Windsor region.

DISCUSSION

These data seem to support a cross-border impact of the Ontario extended drinking policy. A significant increase in alcohol-related motor vehicle casualties was found in the Windsor region and concomitantly, significant decreases in total and alcohol-related motor vehicle casualties were found in the Detroit region after the extended drinking hours amendment. The Ontario government's belief that the extended drinking hour policy would "reduce the number of patrons who cross the border when Ontario's bars and restaurants close" may have been realized.

High-dose risedronate treatment partially preserves cancellous bone mass and microarchitecture during long-term disuse

Disuse induces rapid and severe bone loss in larger mammals as a result of greatly elevated osteoclastic resorption. In this study, we tested whether risedronate (RIS), a potent inhibitor of osteoclastic activity, would effectively prevent cancellous bone loss in female beagles (5-7 years old, N = 28) subjected to single forelimb immobilization (IM) for 12 months. Age-matched, non-IM dogs served as controls (Con). Half the animals from each group received RIS 1 mg/kg p.o. daily (Con + RIS, IM + RIS). Remaining dogs received sterile water (Con, IM). Histomorphometry showed that IM caused a dramatic reduction in cancellous bone mass (-71%) of distal 2nd metacarpals, characterized by marked decreases in trabecular width (-51%) and number (-41%), and 4-fold increases in the indices of bone resorption (eroded surface, osteoclast number, and surface). Bone formation indices (calcein-labeled surface, osteoid surface, and bone formation rate) were also significantly higher in IM than in controls. Activation frequency in IM increased about 4-fold beyond control level. RIS treatment reduced, but did not abolish cancellous bone loss due to immobilization. IM animals treated with RIS lost nearly 50% of cancellous bone mass, while trabecular width and number were reduced by 31% and 25%, respectively. In both RIS-treated control and IM animals, overall bone formation parameters (mineralized bone surface fraction and bone formation rate) remained roughly at intact control levels; however, mineral apposition rate relative to intact control was reduced 40% in RIS-treated control and 86% in RIS-treated IM animals. These results indicate that high-dose RIS treatment might suppress osteoblastic function, especially under long-term disuse. Interestingly, bone resorption parameters in RIS-treated IM animals reached levels even higher than in vehicle-treated IM animals; values for eroded surface, osteoclast number, and surface were 84%, 53%, and 83% above vehicle-treated IM values, respectively. Our data indicate that risedronate treatment is partially effective in preventing cancellous bone loss during long-term disuse. Moreover, our results suggest that bisphosphonates can impair the ability of mature osteoclasts to resorb bone, but cannot overcome the strong stimulus for osteoclast recruitment caused by long-term disuse.