Correction of misaligned slices in multi-slice cardiovascular magnetic resonance using slice-to-volume registration

A popular technique to reduce respiratory motion for cardiovascular magnetic resonance is to perform a multi-slice acquisition in which a patient holds their breath multiple times during the scan. The feasibility of rigid slice-to-volume registration to correct for misalignments of slice stacks in such images due to differing breath-hold positions is explored. Experimental results indicate that slice-to-volume registration can compensate for the typical misalignments expected. Correction of slice misalignment results in anatomically more correct images, as well as improved left ventricular volume measurements. The interstudy reproducibility has also been improved reducing the number of samples needed for cardiac MR studies

Interventions for stroke rehabilitation: analysis of the research contained in the OTseeker evidence database

Purpose: To analyse the stroke content in OTseeker in terms of the quantity of the research evidence, the quality of the randomised controlled trials (RCTs), and the types of interventions and outcome measures used. Method: A survey of stroke-related content in the OTseeker database was conducted in 2007. The year of publication and intervention categories used in each stroke-related RCT and systematic review (SR) were recorded. The internal validity of RCTs using the PEDro scale (partitioned) and the outcome measures used were also recorded. Results: Of the 4,369 articles indexed on OTseeker, 452 (10.3%) related to stroke were conducted between 1979 and 2006. The five most frequently studied intervention categories were movement training (43.2%), models of service delivery (31.2%), physical modalities/orthotics/splinting (30.1%), exercise/stretching/strength training (19.5%), and skill acquisition/training (9.3%). Random allocation (96.1%) was the most frequently satisfied internal validity criterion and therapist blinding (3.1%) was least often satisfied. The five most frequently used outcome measurement categories were basic and extended activities of daily living (70.1%), hand and upper limb function (56.1%), walking/gait (44.1%), movement/motor function (32.7%), and quality of life/general overall health (27.9%). Conclusion: The stroke-related content on OTseeker is useful for allied health professionals. This study highlights a need for better definitions of interventions and consensus about the best outcome measures. Few interventions or outcome measures were participation focused

Initial results of multilevel principal components analysis of facial shape

Traditionally, active shape models (ASMs) do not make a distinction between groups in the subject population and they rely on methods such as (single-level) principal components analysis (PCA). Multilevel principal components analysis (PCA) allows one to model between-group effects and within-group effects explicitly. Three dimensional (3D) laser scans were taken from 240 subjects (38 Croatian female, 35 Croatian male, 40 English female, 40 English male, 23 Welsh female, 27 Welsh male, 23 Finnish female, and 24 Finnish male) and 21 landmark points were created subsequently for each scan. After Procrustes transformation, eigenvalues from mPCA and from single-level PCA based on these points were examined. mPCA indicated that the first two eigenvalues of largest magnitude related to within-groups components, but that the next largest eigenvalue related to between-groups components. Eigenvalues from single-level PCA always had a larger magnitude than either within-group or between-group eigenvectors at equivalent eigenvalue number. An examination of the first mode of variation indicated possible mixing of between-group and within-group effects in single-level PCA. Component scores for mPCA indicated clustering with country and gender for the between-groups components (as ex-pected), but not for the within-group terms (also as expected). Clustering of component scores for single-level PCA was harder to resolve. In conclusion, mPCA is viable method of forming shape models that offers distinct advantages over single-level PCA when groups occur naturally in the subject population

Escherichia coli induces apoptosis and proliferation of mammary cells

Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection, The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1 beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection, Induction of matrix metalloproteinase-g, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue, These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation

Sodium bicarbonate and high-intensity-cycling capacity: variability in responses

Purpose: The aim of this study was to determine whether gastrointestinal (GI) distress affects the ergogenicity of sodium bicarbonate and whether the degree of alkalaemia or other metabolic responses are different between individuals who improve exercise capacity and those who do not. Methods: Twenty-one males completed two cycling capacity tests at 110% of maximum power output. Participants were supplemented with 0.3 g∙kg-1BM of either placebo (maltodextrin) or sodium bicarbonate (SB). Blood pH, bicarbonate, base excess and lactate were determined at baseline, pre-exercise, immediately post-exercise and 5 minutes post-exercise. Results: SB supplementation did not significantly increase total work done (TWD) (P = 0.16, 46.8 ± 9.1 vs. 45.6 ± 8.4 kJ, d = 0.14), although magnitude based inferences suggested a 63% likelihood of a positive effect. When data were analysed without four participants who experienced GI discomfort, TWD (P = 0.01) was significantly improved with SB. Immediately post-exercise blood lactate was higher in SB for the individuals who improved but not for those who didn’t. There were also differences in the pre to post-exercise change in blood pH, bicarbonate and base excess between individuals who improved and individuals who did not. Conclusions: SB improved high intensity cycling capacity, but only with the exclusion of participants experiencing GI discomfort. Differences in blood responses suggest that sodium bicarbonate may not be beneficial to all individuals. Magnitude based inferences suggested that the exercise effects are unlikely to be negative; therefore individuals should determine whether they respond well to sodium bicarbonate supplementation prior to competition

Investigating the association between obesity and asthma in 6- to 8-year-old Saudi children:a matched case-control study

Background: Previous studies have demonstrated an association between obesity and asthma, but there remains considerable uncertainty about whether this reflects an underlying causal relationship. Aims: To investigate the association between obesity and asthma in pre-pubertal children and to investigate the roles of airway obstruction and atopy as possible causal mechanisms. Methods: We conducted an age- and sex-matched case–control study of 1,264 6- to 8-year-old schoolchildren with and without asthma recruited from 37 randomly selected schools in Madinah, Saudi Arabia. The body mass index (BMI), waist circumference and skin fold thickness of the 632 children with asthma were compared with those of the 632 control children without asthma. Associations between obesity and asthma, adjusted for other potential risk factors, were assessed separately in boys and girls using conditional logistic regression analysis. The possible mediating roles of atopy and airway obstruction were studied by investigating the impact of incorporating data on sensitisation to common aeroallergens and measurements of lung function. Results: BMI was associated with asthma in boys (odds ratio (OR)=1.14, 95% confidence interval (CI), 1.08–1.20; adjusted OR=1.11, 95% CI, 1.03–1.19) and girls (OR=1.37, 95% CI, 1.26–1.50; adjusted OR=1.38, 95% CI, 1.23–1.56). Adjusting for forced expiratory volume in 1 s had a negligible impact on these associations, but these were attenuated following adjustment for allergic sensitisation, particularly in girls (girls: OR=1.25; 95% CI, 0.96–1.60; boys: OR=1.09, 95% CI, 0.99–1.19). Conclusions: BMI is associated with asthma in pre-pubertal Saudi boys and girls; this effect does not appear to be mediated through respiratory obstruction, but in girls this may at least partially be mediated through increased risk of allergic sensitisation

Can peer education improve beliefs, knowledge, motivation and intention to engage in falls prevention amongst community-dwelling older adults?

The aim of the study was to evaluate the effectiveness of delivering a contemporary peer-led falls prevention education presentation on community-dwelling older adults’ beliefs, knowledge, motivation and intention to engage in falls prevention strategies. A two-group quasi-experimental pre-test–post-test study using a convenience sample was conducted. A new falls prevention training package for peer educators was developed, drawing on contemporary adult learning and behaviour change principles. A 1-h presentation was delivered to community-dwelling older adults by peer educators trained with the new package (intervention group). Control group participants received an existing, 1-h falls prevention presentation by trained peer educators who had not received the adult learning and behaviour change training. Participants in both groups completed a purpose-developed questionnaire at pre-presentation, immediately post-presentation and at one-month follow-up. Participants’ levels of beliefs, knowledge, motivation and intention were compared across these three points of time. Generalised estimating equations models examined associations in the quantitative data, while deductive content analysis was used for qualitative data. Participants (control n = 99; intervention n = 133) in both groups showed significantly increased levels of beliefs and knowledge about falls prevention, and intention to engage in falls prevention strategies over time compared to baseline. The intervention group was significantly more likely to report a clear action plan to undertake falls prevention strategies compared to the control group. Peer-led falls prevention education is an effective approach for raising older adults’ beliefs, knowledge and intention to engage in falls prevention strategies

Efficiency of primary saliva secretion: an analysis of parameter dependence in dynamic single-cell and acinus models, with application to aquaporin knockout studies

Secretion from the salivary glands is driven by osmosis following the establishment of osmotic gradients between the lumen, the cell and the interstitium by active ion transport. We consider a dynamic model of osmotically driven primary saliva secretion and use singular perturbation approaches and scaling assumptions to reduce the model. Our analysis shows that isosmotic secretion is the most efficient secretion regime and that this holds for single isolated cells and for multiple cells assembled into an acinus. For typical parameter variations, we rule out any significant synergistic effect on total water secretion of an acinar arrangement of cells about a single shared lumen. Conditions for the attainment of isosmotic secretion are considered, and we derive an expression for how the concentration gradient between the interstitium and the lumen scales with water- and chloride-transport parameters. Aquaporin knockout studies are interpreted in the context of our analysis and further investigated using simulations of transport efficiency with different membrane water permeabilities. We conclude that recent claims that aquaporin knockout studies can be interpreted as evidence against a simple osmotic mechanism are not supported by our work. Many of the results that we obtain are independent of specific transporter details, and our analysis can be easily extended to apply to models that use other proposed ionic mechanisms of saliva secretion

Renal epithelial cells retain primary cilia during human acute renal allograft rejection injury

OBJECTIVES: Primary cilia are sensory organelles which co-ordinate several developmental/repair pathways including hedgehog signalling. Studies of human renal allografts suffering acute tubular necrosis have shown that length of primary cilia borne by epithelial cells doubles throughout the nephron and collecting duct, and then normalises as renal function returns. Conversely the loss of primary cilia has been reported in chronic allograft rejection and linked to defective hedgehog signalling. We investigated the fate of primary cilia in renal allografts suffering acute rejection. RESULTS: Here we observed that in renal allografts undergoing acute rejection, primary cilia were retained, with their length increasing 1 week after transplantation and remaining elevated. We used a mouse model of acute renal injury to demonstrate that elongated renal primary cilia in the injured renal tubule show evidence of smoothened accumulation, a biomarker for activation of hedgehog signalling. We conclude that primary cilium-mediated activation of hedgehog signalling is still possible during the acute phase of renal allograft rejection