Effect of tibial re-alignment surgery on single leg standing balance in patients with knee osteoarthritis

Background

Standing balance is impaired in individuals with knee osteoarthritis and is associated with disease severity. The effects of surgical interventions on standing balance have received little attention. The purpose of the present study was to examine measures of balance during tests of single-limb standing before and after medial opening wedge high tibial osteotomy – a lower limb re-alignment procedure for those with varus alignment and knee osteoarthritis.

Methods

Standing balance was assessed in 49 individuals prior to and 12 months following medial opening wedge high tibial osteotomy. Participants performed three trials of single-limb balance lasting 10 s each while standing on a force platform. Anteroposterior and mediolateral coordinates of the centre of pressure were obtained from the force platform and used to calculate the total centre of pressure path length as well as the range and variability (standard deviation) of the anteroposterior and mediolateral coordinates.

Findings

Though all centre of pressure measures were lower following high tibial osteotomy, none reached statistical significance (P > 0.05) and effect sizes were small (d < 0.34). The largest mean improvement was 7.6% (95% confidence interval: −0.7–15.8%).

Interpretation

Results indicate that standing balance in individuals with knee osteoarthritis is not significantly different following high tibial osteotomy surgery. Standing balance in this patient population is a complex process not entirely dictated by disease symptoms or structural factors such as alignment.     

Measures of frontal plane lower limb alignment obtained from static radiographs and dynamic gait analysis

Currently, lower limb alignment is measured statically from radiographs that may not accurately represent the condition of the limb when moving and weight-bearing. Thus, the purpose of the present study was to introduce and examine a novel measure of dynamic lower limb alignment obtained during walking in patients with knee OA. In this cross-sectional study, standing, full-length lower limb radiographs were acquired from 80 individuals with confirmed knee OA, who also underwent three-dimensional gait analyses with reflective markers placed on the segments of the lower limb. Frontal plane lower limb alignment was measured using the static radiographs (mechanical axis) and gait analyses (marker-based alignment) by identifying the centres of the hip, knee, and ankle from both methods. Simple linear regression indicated these measures were highly correlated (r = 0.84), however, 30% of the variance in the marker-based measure of lower limb alignment was not explained by the mechanical axis despite using the same anatomical landmarks. Results from this study suggest that a valid measure of dynamic lower limb alignment can be obtained from a standard quantitative gait analysis and highlight the differences in measures of lower limb alignment obtained in static and dynamic situations. Future research into the clinical utility of measures of dynamic alignment in the treatment of OA may aid in the development of interventions specifically tailored to one's dynamic lower limb biomechanics during gait.     

The applicability of a recovery approach to nursing people with dementia

Objectives

Recent developments in nursing to people with mental health conditions of working age have been underpinned by the recovery approach. This paper critically reviews the idea of recovery in relationship to people with dementia and examines its applicability to dementia care nursing.

Design

The paper critically reviews literature relating to the use recovery approach and the people with dementia, particularly their nursing care. The paper identifies common ideas within two approaches and suggests how the recovery approach may underpin nursing care to people with dementia.

Data sources

A search of CINAHL, Medline and PsycINFO was undertaken from 1987 onwards using keywords ‘recovery’, ‘nursing’ and ‘dementia’.

Results

The paper found that the recovery approach shares many ideas with person-centred approaches to dementia care and illustrates this in relationship to well-being, social inclusion, self-management, and hope.

Conclusion

The paper concludes by suggesting that dementia care nursing should draw on ideas taken from the recovery approach and identifies each approach drawing on ideas that have come together in postpsychiatry.     

Targeted Delivery of a Photosensitizer to Aggregatibacter actinomycetemcomitans Biofilm

The ability to selectively target specific biofilm species with antimicrobials would enable control over biofilm consortium composition, with medical applications in treatment of infections on mucosal surfaces that are colonized by a mixture of beneficial and pathogenic microorganisms. We functionalized a genetically engineered multimeric protein with both a targeting moiety (biotin) and either a fluorophore or a photosensitizer (SnCe6). Biofilm microcolonies of Aggregatibacter actinomycetemcomitans, a periodontal pathogen, were targeted with the multifunctional dodecamer. Streptavidin was used to couple biotinylated dodecamer to a biotinylated anti-A. actinomycetemcomitans antibody. This modular targeting approach enabled us to increase the loading of photosensitizer onto the cells by a cycle of amplification. Scanning laser confocal microscopy was used to characterize transport of fluorescently tagged dodecamer into the microcolonies and targeting of the cells with biotin-labeled, fluorescently tagged dodecamer. Light-induced activity of the targeted photosensitizer reduced the viability of A. actinomycetemcomitans biofilm, as indicated by membrane permeability to propidium iodide. The functionalized multimeric protein promises to be a useful tool for controlling periodontal biofilm consortia and offers a modular design whereby moieties that target different species can be readily combined with the functionalized protein construct.Therapeutic tools that enabled targeted delivery of antimicrobials to specific species in biofilms would expand our capability to treat chronic infections associated with mucosal surfaces where complete sterility is not the natural healthy condition. The oral cavity and the gut are prime examples of mucosal surfaces at which the immune system maintains a healthy microbial presence (3, 50). Mucosal surfaces in the oral cavity are nonsterile environments colonized by biofilm consortia (38). In the gut, some commensals are true symbionts (30, 36), and similarly, it is hypothesized that oral commensals may aid in maintaining a healthy immune homeostasis (35). The implication is that treatment of oral diseases such as periodontal disease can be made more effective by selective elimination of pathogens. By extension, we may also find that tools that enable specific targeting of biofilm pathogens provide effective treatments for chronic infections of the gut (31).A class of multimeric proteins that self-assemble into highly symmetric quaternary structures (7, 52) shows promise for development into delivery vehicles for therapeutic (15, 16, 44) and imaging agents (41, 51). We selected one of these proteins, a relatively small, spherical, 9-nm-diameter dodecamer, originally isolated from Listeria inocula (LiDps) (21), for targeted delivery of a photosensitizer to Aggregatibacter actinomycetemcomitans biofilm. We genetically added a tetrapeptide to the C terminus of each of the 12 monomeric 18-kDa subunits of LiDps. Cysteines incorporated into this tetrapeptide were labeled with biotin. Since the C terminus is presented on the exterior surface of the assembled dodecamer, these biotins were readily available for binding to streptavidin, a universal coupling protein. An SnCe6 photosensitizer was covalently linked to intrinsic lysines.Photosensitizers are compounds that produce reactive oxygen species (ROS) upon excitation by light (25). Antimicrobial photodynamic therapy (PDT) has been shown to be effective against oral pathogens (6, 29, 54). SnCe6 has been used previously for targeted antimicrobial PDT (10-12). The primary modes of action of photosensitizers are membrane disruption and, if the photosensitizer is internalized, DNA damage (19). The antimicrobial activity of ROS produced by light-activated photosensitizers is relatively localized. This is especially the case for singlet oxygen (diffusion length of <50 nm), which is thought to be the primary ROS causing cell death (32). The localized action of photosensitizers makes them attractive agents for targeted antimicrobial therapy.The LiDps genetic construct, dual functionalized with SnCe6 and biotin, is a modular unit that can be combined with any targeting moiety that can be biotinylated. This would accommodate a variety of approaches that have been used to target microbial pathogens, including lectin/carbohydrate interactions (53), antimicrobial peptides (8, 22), and the lysins isolated from bacteriophage (14). We chose to use an antibody as the targeting moiety for these studies since monoclonal antibodies are available for a number of the prevalent periodontal pathogens (5, 9, 17). In addition, antibodies offer a wide range of potential cell surface targets combined with the possibility to engineer high binding affinities (4).A. actinomycetemcomitans is a Gram-negative periodontal pathogen implicated as the primary etiological agent in localized aggressive periodontitis (13, 37). Rough colony variants isolated from sites of infection form discrete microcolonies when cultured in vitro which exhibit distinctive cohesive as well as adhesive properties (27). We characterized transport of the LiDps dodecamer to the base of A. actinomycetemcomitans microcolonies, demonstrated targeting of the LiDps to the cells in the microcolonies, and showed that SnCe6 targeted to 24-h biofilms produced light-activated membrane disruption. The modular design enabled us to use cycles of alternating exposure to the streptavidin and the LiDps dodecamer to increase the loading of targeted photosensitizer onto the cells.     

Hemodynamic predictors of aortic dilatation in bicuspid aortic valve by velocity-encoded cardiovascular magnetic resonance

Background

Congenital Bicuspid Aortic Valve (BAV) is a significant risk factor for serious complications including valve dysfunction, aortic dilatation, dissection, and sudden death. Clinical tools for identification and monitoring of BAV patients at high risk for development of aortic dilatation, an early complication, are not available.

Methods

This paper reports an investigation in 18 pediatric BAV patients and 10 normal controls of links between abnormal blood flow patterns in the ascending aorta and aortic dilatation using velocity-encoded cardiovascular magnetic resonance. Blood flow patterns were quantitatively expressed in the angle between systolic left ventricular outflow and the aortic root channel axis, and also correlated with known biochemical markers of vessel wall disease.

Results

The data confirm larger ascending aortas in BAV patients than in controls, and show more angled LV outflow in BAV (17.54 ± 0.87 degrees) than controls (10.01 ± 1.29) (p = 0.01). Significant correlation of systolic LV outflow jet angles with dilatation was found at different levels of the aorta in BAV patients STJ: r = 0.386 (N = 18, p = 0.048), AAO: r = 0.536 (N = 18, p = 0.022), and stronger correlation was found with patients and controls combined into one population: SOV: r = 0.405 (N = 28, p = 0.033), STJ: r = 0.562 (N = 28, p = 0.002), and AAO r = 0.645 (N = 28, p < 0.001). Dilatation and the flow jet angle were also found to correlate with plasma levels of matrix metallo-proteinase 2.

Conclusions

The results of this study provide new insights into the pathophysiological processes underlying aortic dilatation in BAV patients. These results show a possible path towards the development of clinical risk stratification protocols in order to reduce morbidity and mortality for this common congenital heart defect.     

A comparison of the efficacy and rate of response to oral and intravenous Vitamin K in reversal of over-anticoagulation with warfarin

The role of oral Vitamin K administration in the reversal of anticoagulation is not yet clear because of a paucity of data on the early effects of treatment, apparent differences in efficacy between preparations and a lack of data comparing oral with intravenous administration. We have compared the effects on the International Normalized Ratio (INR) and activities of the Vitamin K-dependent clotting factors II, VII, IX and X at 4 h and 24 h after administration of three oral Vitamin K preparations and of intravenous Vitamin K in 64 anticoagulated patients who required non-urgent partial correction of anticoagulation. Our data confirm that correction of anticoagulation is more rapid after intravenous administration of Vitamin K than after oral administration of similar or larger doses. At 24 h, satisfactory correction of INR can be achieved using low-dose Vitamin K given by either the intravenous or oral route. Our data, and that from previous studies, suggest that there may be differences in efficacy between orally administered products. Administration of Vitamin K by either route was accompanied by changes in the activities of the Vitamin K-dependent clotting factors that reflected their respective biological half-lives. In the 24 h after treatment, the relationship between the INR and the individual Vitamin K-dependent clotting factors was similar to that described previously in stable anticoagulated patients. We conclude that the reversal of anticoagulation with warfarin is achieved more rapidly by intravenous administration of Vitamin K. Satisfactory, but slower, reversal of anticoagulation can be effected using oral Vitamin K, but there may be differences in efficacy between the products tested in our study.     

A Preliminary Investigation of Barriers Faced by Male Early Childhood Pre-Service Teachers

Despite calls for a balanced gender profile, a recent preliminary study that explored issues related to the low rate of applications and high attrition rate of males in a four year undergraduate Bachelor of Early Childhood Education degree indicated that early childhood pre-service intake was mainly comprised of female students. Most males did not choose early childhood education as their first preference in tertiary studies and they tended to fall away from this area between the orientation period and the actual commencement of the academic program. Those who stayed reported experiencing few institutional barriers to participation and completion of their studies but although participants considered the early childhood degree to be appropriate for both male and female students, only 48% of female participants thought that both males and females had equal chances of obtaining employment.     

Medical migration and Africa: an unwanted legacy of educational change

The opportunities given for medical staff to travel, work and remain in countries other than that of their domicile or graduation have led to the phenomenon of medical migration. This has been supported by ease of travel, improved technology and a drive to share good examples of medical education through improved communication. Whilst these opportunities create positive advantages to the individuals and countries involved, through the transfer of knowledge and medical management, the situation does not always lead to long term benefits, and clear disadvantages begin to emerge. The gulf between the developed and developing countries becomes pronounced, leading to a general drift of resources away from the areas where they are most needed and subsequent profound effects upon the indigenous population. This paper suggests that it is a responsibility of medical educators throughout the world to recognize this effect and create opportunities whereby the specialty of medical education positively effects medical migration to the benefit of the less fortunate areas of the world.