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1.
J Infect ; 76(4): 383-392, 2018 04.
Article in English | MEDLINE | ID: mdl-29248587

ABSTRACT

BACKGROUND: Limited data exist describing supportive care management, laboratory abnormalities and outcomes in patients with Ebola virus disease (EVD) in West Africa. We report data which constitute the first description of the provision of enhanced EVD case management protocols in a West African setting. METHODS: Demographic, clinical and laboratory data were collected by retrospective review of clinical and laboratory records of patients with confirmed EVD admitted between 5 November 2014 and 30 June 2015. RESULTS: A total of 44 EVD patients were admitted (median age 37 years (range 17-63), 32/44 healthcare workers), and excluding those evacuated, the case fatality rate was 49% (95% CI 33%-65%). No pregnant women were admitted. At admission 9/44 had stage 1 disease (fever and constitutional symptoms only), 12/44 had stage 2 disease (presence of diarrhoea and/or vomiting) and 23/44 had stage 3 disease (presence of diarrhoea and/or vomiting with organ failure), with case fatality rates of 11% (95% CI 1%-58%), 27% (95% CI 6%-61%), and 70% (95% CI 47%-87%) respectively (p = 0.009). Haemorrhage occurred in 17/41 (41%) patients. The majority (21/40) of patients had hypokalaemia with hyperkalaemia occurring in 12/40 patients. Acute kidney injury (AKI) occurred in 20/40 patients, with 14/20 (70%, 95% CI 46%-88%) dying, compared to 5/20 (25%, 95% CI 9%-49%) dying who did not have AKI (p = 0.01). Ebola virus (EBOV) PCR cycle threshold value at baseline was mean 20.3 (SD 4.3) in fatal cases and 24.8 (SD 5.5) in survivors (p = 0.007). Mean national early warning score (NEWS) at admission was 5.5 (SD 4.4) in fatal cases and 3.0 (SD 1.9) in survivors (p = 0.02). Central venous catheters were placed in 37/41 patients and intravenous fluid administered to 40/41 patients (median duration of 5 days). Faecal management systems were inserted in 21/41 patients, urinary catheters placed in 27/41 and blood component therapy administered to 20/41 patients. CONCLUSIONS: EVD is commonly associated life-threatening electrolyte imbalance and organ dysfunction. We believe that the enhanced levels of protocolized care, scale and range of medical interventions we report, offer a blueprint for the future management of EVD in resource-limited settings.


Subject(s)
Case Management , Hemorrhagic Fever, Ebola/therapy , Hospitalization/statistics & numerical data , Palliative Care/methods , Adolescent , Adult , Africa, Western/epidemiology , Diarrhea/epidemiology , Diarrhea/virology , Ebolavirus/pathogenicity , Electrolytes , Female , Fever/epidemiology , Fever/virology , Health Resources , Hemorrhagic Fever, Ebola/epidemiology , Hospital Records , Humans , Male , Middle Aged , Military Facilities , Retrospective Studies , Sierra Leone/epidemiology , United Kingdom , Viral Load , Young Adult
2.
J Infect ; 74(6): 585-589, 2017 06.
Article in English | MEDLINE | ID: mdl-28344116

ABSTRACT

AIMS: A prospective observational study was conducted in Royal Marines (RM) recruits to investigate throat carriage of group A Streptococcus (GAS) and incidence of soft tissue infections. METHODS: 1012 RM recruits were followed through a 32-week training programme, with throat swabs being obtained in weeks 1, 6, 15, and 32. Alongside a separate cohort of 46 RM Young Officers (YO) undergoing training were sampled in parallel. RESULTS: Carriage of group A Streptococcus was detected in only 5/1012 (0.49%) recruits at the beginning of training and remained low throughout training. There was no association between GAS carriage and development of soft tissue infection. There was no carriage of GAS in the smaller YO cohort at the start of training, (0/46). At week 6, a surge in GAS carriage was detected in 8/46 (17%) YO, that could be ascribed to a cluster of GAS genotype emm83. CONCLUSIONS: Asymptomatic GAS carriage is very infrequent among young adults in England and this should be borne in mind when considering the relevance of a positive throat swab result in symptomatic patients or outbreaks. Despite low prevalence, there is however potential for GAS to rapidly and transiently disseminate among adults during outbreaks.


Subject(s)
Asymptomatic Infections/epidemiology , Carrier State/epidemiology , Military Personnel , Pharynx/microbiology , Streptococcal Infections/epidemiology , Streptococcus pyogenes/isolation & purification , Adolescent , Adult , Carrier State/microbiology , Disease Outbreaks , England/epidemiology , Female , Humans , Male , Prospective Studies , Soft Tissue Infections/epidemiology , Soft Tissue Infections/microbiology , Streptococcal Infections/microbiology , Streptococcus pyogenes/genetics , Young Adult
4.
Bioresour Technol ; 194: 263-9, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26210138

ABSTRACT

This study investigated the conversion of Lemna minor biomass to bioethanol. The biomass was pre-treated by steam explosion (SE, 210°C, 10 min) and then subjected to simultaneous saccharification and fermentation (SSF) using Cellic® CTec 2 (20 U or 0.87 FPU g(-1) substrate) cellulase plus ß-glucosidase (2 U g(-1) substrate) and a yeast inoculum of 10% (v/v or 8.0×10(7) cells mL(-1)). At a substrate concentration of 1% (w/v) an ethanol yield of 80% (w/w, theoretical) was achieved. However at a substrate concentration of 20% (w/v), the ethanol yield was lowered to 18.8% (w/w, theoretical). Yields were considerably improved by increasing the yeast titre in the inoculum or preconditioning the yeast on steam exploded liquor. These approaches enhanced the ethanol yield up to 70% (w/w, theoretical) at a substrate concentration of 20% (w/v) by metabolising fermentation inhibitors.


Subject(s)
Araceae/metabolism , Carbohydrate Metabolism , Ethanol/metabolism , Fermentation , Saccharomyces cerevisiae/metabolism , Steam , Biomass , Cellulase/metabolism , beta-Glucosidase/metabolism
6.
Osteoarthritis Cartilage ; 23(9): 1483-90, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25907860

ABSTRACT

OBJECTIVE: Our objective was to investigate relationships between proximal tibial subchondral bone mineral density (BMD) and nocturnal pain in patients with knee osteoarthritis (OA). METHODS: The preoperative knee of 42 patients booked for knee arthroplasty was scanned using quantitative computed tomography (QCT). Pain was measured using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and participants were categorized into three groups: 'no pain', 'moderate pain', and 'severe pain' while lying down at night. We used depth-specific image processing to assess tibial subchondral BMD at normalized depths of 0-2.5 mm, 2.5-5.0 mm and 5-10 mm relative to the subchondral surface. Regional analyses of each medial and lateral plateau included total BMD and maximum BMD within a 10 mm diameter core or 'focal spot'. The association between WOMAC pain scores and BMD measurements was assessed using Spearman's rank correlation. Regional BMD was compared pairwise between pain and no pain groups using multivariate analysis of covariance using age, sex, and BMI as covariates and Bonferroni adjustment for multiple comparisons. RESULTS: Lateral focal BMD at the 2.5-5 mm depth was related to nocturnal pain (ρ = 0.388, P = 0.011). The lateral focal BMD was 33% higher in participants with 'severe pain' than participants with 'no pain' at 2.5-5 mm depth (P = 0.028) and 32% higher at 5-10 mm depth (P = 0.049). There were no BMD differences at 0-2.5 mm from the subchondral surface. CONCLUSION: This study suggests that local subchondral bone density may have a role in elucidating OA-related pain pathogenesis.


Subject(s)
Bone Density/physiology , Osteoarthritis, Knee/diagnostic imaging , Osteoarthritis, Knee/physiopathology , Pain/complications , Tibia/diagnostic imaging , Aged , Female , Humans , Male , Middle Aged , Pain/etiology , Retrospective Studies , Tomography, X-Ray Computed
7.
Med Eng Phys ; 37(1): 93-9, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25466777

ABSTRACT

Muscle moment arms are used widely in biomechanical analyses. Often they are measured in 2D or at a series of static joint positions. In the present study we demonstrate a simple MRI method for measuring muscle moment arms dynamically in 3D from a single range-of-motion cycle. We demonstrate this method in the Achilles tendon for comparison with other methods, and validate the method using a custom apparatus. The method involves registration of high-resolution joint geometry from MRI scans of the stationary joint with low-resolution geometries from ultrafast MRI scans of the slowly moving joint. Tibio-talar helical axes and 3D Achilles tendon moment arms were calculated throughout passive rotation for 10 adult subjects, and compared with recently published data. A simple validation was conducted by comparing MRI measurements with direct physical measurements made on a phantom. The moment arms measured using our method and those of others were similar and there was good agreement between physical measurements (mean 41.0mm) and MRI measurements (mean 39.5mm) made on the phantom. This new method can accurately measure muscle moment arms from a single range-of-motion cycle without the need to control rotation rate or gate the scanning. Supplementary data includes custom software to assist implementation.


Subject(s)
Achilles Tendon , Ankle Joint , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Movement , Muscle, Skeletal , Achilles Tendon/anatomy & histology , Achilles Tendon/physiology , Adult , Animals , Ankle Joint/anatomy & histology , Ankle Joint/physiology , Biomechanical Phenomena , Equipment Design , Female , Humans , Imaging, Three-Dimensional/instrumentation , Magnetic Resonance Imaging/instrumentation , Male , Middle Aged , Models, Biological , Movement/physiology , Muscle, Skeletal/anatomy & histology , Muscle, Skeletal/physiology , Phantoms, Imaging , Rotation , Sheep , Young Adult
8.
Bone Joint J ; 96-B(9): 1214-21, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25183593

ABSTRACT

Although it is clear that opening-wedge high tibial osteotomy (HTO) changes alignment in the coronal plane, which is its objective, it is not clear how this procedure affects knee kinematics throughout the range of joint movement and in other planes. Our research question was: how does opening-wedge HTO change three-dimensional tibiofemoral and patellofemoral kinematics in loaded flexion in patients with varus deformity?Three-dimensional kinematics were assessed over 0° to 60° of loaded flexion using an MRI method before and after opening-wedge HTO in a cohort of 13 men (14 knees). Results obtained from an iterative statistical model found that at six and 12 months after operation, opening-wedge HTO caused increased anterior translation of the tibia (mean 2.6 mm, p < 0.001), decreased proximal translation of the patella (mean -2.2 mm, p < 0.001), decreased patellar spin (mean -1.4°, p < 0.05), increased patellar tilt (mean 2.2°, p < 0.05) and changed three other parameters. The mean Western Ontario and McMaster Universities Arthritis Index improved significantly (p < 0.001) from 49.6 (standard deviation (sd) 16.4) pre-operatively to a mean of 28.2 (sd 16.6) at six months and a mean of 22.5 (sd 14.4) at 12 months. The three-dimensional kinematic changes found may be important in explaining inconsistency in clinical outcomes, and suggest that measures in addition to coronal plane alignment should be considered.


Subject(s)
Bone Anteversion/surgery , Imaging, Three-Dimensional , Knee Joint/physiopathology , Magnetic Resonance Imaging/methods , Osteoarthritis, Knee/surgery , Osteotomy/methods , Adult , Biomechanical Phenomena , Bone Anteversion/complications , Female , Follow-Up Studies , Humans , Knee Joint/surgery , Male , Middle Aged , Models, Statistical , Osteoarthritis, Knee/complications , Osteoarthritis, Knee/physiopathology , Range of Motion, Articular , Treatment Outcome , Weight-Bearing
9.
J R Army Med Corps ; 160(2): 99-101, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24434764

ABSTRACT

Military research performed in an operational environment involves mission-specific considerations. The Institute of Naval Medicine was tasked in 2008 by the Surgeon General to investigate the nutritional status of deployed British military personnel, and how this might affect body composition, physical fitness and operational capability. This paper briefly describes the logistic and technical issues specific to military research that were encountered by the study team, how these issues were overcome and how this research has influenced military practice.


Subject(s)
Biomedical Research/methods , Military Medicine , Military Personnel , Nutritional Status , Cohort Studies , Humans , Physical Fitness
10.
Osteoporos Int ; 25(3): 1107-14, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24221452

ABSTRACT

SUMMARY: Computed tomography-based depth-specific image processing is able to precisely identify regional differences between healthy patellae and patellae with osteoarthritis. INTRODUCTION: This study aims to assess the precision errors and potential differences in regional, depth-specific subchondral bone mineral density (BMD) in normal and osteoarthritic (OA) human patellae in vivo using CT-based density analyses. METHODS: Fourteen participants (2 men and 12 women; mean age, 51.4; SD, 11.8 years) were scanned using clinical quantitative CT (QCT) three times over 2 days. Participants were categorized as either normal (n = 7) or exhibiting radiographic OA (n = 7). Average subchondral BMD was assessed at three depths relative to the subchondral surface. Regional BMD analysis included: total lateral facet BMD, total medial facet BMD, and superior/middle/inferior BMD of lateral and medial facets at normalized depths of 0-2.5, 2.5-5, and 5-7.5 mm from the subchondral surface. We assessed precision using root mean square coefficients of variation (CV%). We evaluated differences between OA and normal BMD by (1) calculating percentage differences between the groups (in relation to normal BMD) (2) relating percentage differences to respective CV% errors and (3) determining effect sizes using Cohen's d. RESULTS: Root mean square CV% precision errors ranged from 1.1 to 5.9 %. Percentage differences between OA and normal BMD varied from -1.6 to -30.1 % (BMD lower in OA patellae). In relation to precision errors, percentage differences were, on average, 5.5× greater than CV% errors. Cohen's d effect sizes ranged from -1.7 to -0.1. Largest differences were noted at depths of 2.5-5 and 5-7.5 mm from the subchondral surface. CONCLUSIONS: Patellar subchondral BMD measures were precise (average CV%, ≤3 %). This region- and depth-specific CT-based imaging tool characterized regional standardized BMD differences between normal and OA patellae in vivo.


Subject(s)
Bone Density/physiology , Osteoarthritis, Knee/physiopathology , Patella/physiopathology , Adult , Aged , Female , Humans , Knee Joint/diagnostic imaging , Knee Joint/physiopathology , Male , Middle Aged , Osteoarthritis, Knee/diagnostic imaging , Patella/diagnostic imaging , Patella/physiology , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Young Adult
11.
J R Army Med Corps ; 159(3): 237-9, 2013 Sep.
Article in English | MEDLINE | ID: mdl-24109146

ABSTRACT

INTRODUCTION: Infections due to multidrug-resistant organisms are increasingly prevalent, and antimicrobial stewardship has become a priority for many healthcare organisations, including the Defence Medical Services. In military environments, infectious diseases remain a significant burden, and infections complicating the care of modern complex combat injuries are well recognised. A focus on infection prevention and control in the deployed environment is essential, and an important element of this is an antimicrobial formulary and stewardship programme. This audit analyses antimicrobial prescribing practices by military clinicians in patients admitted to UK/US Role 3 medical treatment facility in Camp Bastion, Afghanistan, relative to the UK published guidance. METHODS: Retrospective case note review of all in-patient admissions during two time periods (October 2011 and October 2012). Notes were independently reviewed by an infection specialist not involved in the management of the patients. RESULTS: 475 case notes were reviewed, of which 250 received antimicrobials. Coalition forces represented the most common patient group (131/250), with battle injury the most frequent indication (139/250) for antimicrobial prescription, followed by disease (100/250). A total of 302 antimicrobials were prescribed, with co-amoxiclav being the most frequently used antibiotic in 74% (185/250) of patients. 84.8% (212/250) were prescribed antimicrobials in line with the antimicrobial formulary. In battle injury, 93.5% (130/139) of antimicrobial prescriptions were in line with the formulary compared with 73.9% (82/111) in disease and non-battle injury patients. CONCLUSIONS: Maintaining a strong infection control effort in the deployed setting, even in a stabilised operational environment, is difficult, but our data show good compliance to the antimicrobial formulary superior to that reported in civilian hospitals. To improve this, further innovative strategies are required, combined with a continued focus on infection control basics across the full spectrum of care.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Hospitals, Military , Mobile Health Units , Practice Patterns, Physicians' , Clinical Audit , Guideline Adherence , Humans , Retrospective Studies , United Kingdom , United States
12.
Int J Food Microbiol ; 152(3): 175-80, 2012 Jan 16.
Article in English | MEDLINE | ID: mdl-21439667

ABSTRACT

In recent years the application of cold atmospheric gas plasma (CAP) aimed at the removal of microbial contamination from fresh and minimally processed food has received increased attention. For CAP to be successfully adopted by the food production industry, factors which affect its potential for microbial inactivation must be evaluated. In this study, we examined the effects of initial microbial concentration, present on filter discs, on the inactivation of Salmonella enterica serovar Typhimurium (S. Typhimurium) with nitrogen CAP. It was found that the rate of inactivation of S. Typhimurium is inversely proportional to initial bacterial concentration, with the D-value observed at the highest cell concentration assayed (10(8) CFU/filter) being 14 fold higher than seen at the lowest starting concentration (10(5) CFU/filter). Addition of increasing concentrations of Pseudomonas fluorescens cells to a Salmonella population of 10(5) CFU/filter resulted in an exponential decrease in the rate of killing of the Salmonella cells. However, whilst the addition of heat-killed S. Typhimurium cells to 10(5) CFU/filter live S. Typhimurium cells resulted in a significant decrease in the killing rate, this effect was dose independent. This suggests that although biomass plays a role in the protection against CAP inactivation seen at high cell densities, dead cells and their components released during the heating period are not as effective as viable cells. Fluorescence microscopy showed that, unlike the single dispersed cells observed at low cell densities, at higher cell densities bacteria were present in a multilayered structure. This phenomenon could explain the reduced inactivation by the plasma, since the top layer may present a physical barrier that protects underlying cells. In conclusion, this work clearly shows a link between bacterial cell density and the efficacy of CAP inactivation, making an important contribution to the understanding of this alternative food processing technology, which should be taken into account in both further studies and in the practical application of this technique to the food industry.


Subject(s)
Food Microbiology , Microbial Viability , Salmonella typhimurium/growth & development , Food Handling , Plasma Gases , Pseudomonas fluorescens/growth & development
13.
J Psychiatr Ment Health Nurs ; 19(7): 587-93, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22070354

ABSTRACT

The immense stress associated with experiencing and surviving childhood sexual abuse directly influences coping, immune function and overall health. Lifelong overuse of maladaptive coping strategies results in impaired adjustment to stress. The purpose of this research was to re-examine if stress management education would be effective in improving coping skills for this population. Two 4-week series of stress management workshops were completed by 32 adult survivors who completed the ways of coping questionnaire before and after the training. Four categories of coping showed significant change. Stress management education is an effective and cost-efficient approach that gives adult survivors an empowering set of tools for their healing journey.


Subject(s)
Adult Survivors of Child Abuse/psychology , Child Abuse, Sexual/therapy , Stress, Psychological/therapy , Adaptation, Psychological , Adult , Aged , Child , Child Abuse, Sexual/psychology , Female , Humans , Middle Aged , Social Support , Stress, Psychological/etiology , Stress, Psychological/psychology , Young Adult
14.
Anal Chem ; 83(19): 7400-7, 2011 Oct 01.
Article in English | MEDLINE | ID: mdl-21854049

ABSTRACT

SIRT6 is a histone deacetylase that has been proposed as a potential therapeutic target for metabolic disorders and the prevention of age-associated diseases. Thus, the identification of compounds that modulate SIRT6 activity could be of great therapeutic importance. The aim of this study was to develop a screening method for the identification of novel modulators of SIRT6 from a natural plant extract. We immobilized SIRT6 onto the surface of magnetic beads, and assessed SIRT6 enzymatic activity on synthetic acetylated histone tails (H3K9Ac) by measuring products of the deacetylation process. The SIRT6 coated magnetic beads were then suspended in fenugreek seed extract (Trigonella foenum-graecum) as a bait to identify active ligands that suppress SIRT6 activity. While the entire extract also inhibited SIRT6 activity in a cell-based assay, the inhibitory effect of two flavonoids from this extract, quercetin and vitexin, was only detected in vitro. This is the first report on the use of protein-coated magnetic beads for the identification of an active ligand from a botanical matrix, and it sets the basis for the de novo identification of SIRT6 modulators from complex biological mixtures.


Subject(s)
Enzyme Inhibitors/pharmacology , Enzymes, Immobilized/antagonists & inhibitors , Histone Deacetylases/metabolism , Magnets/chemistry , Plant Extracts/pharmacology , Trigonella/chemistry , Animals , Biocatalysis , Cells, Cultured , Chickens , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Histone Deacetylases/chemistry , Histone Deacetylases/deficiency , Mass Spectrometry , Plant Extracts/chemical synthesis , Plant Extracts/chemistry , Recombinant Fusion Proteins/antagonists & inhibitors , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/metabolism , Seeds/chemistry , Structure-Activity Relationship , Surface Properties
15.
Osteoarthritis Cartilage ; 19(7): 801-8, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21397707

ABSTRACT

OBJECTIVE: Patellar bracing is a mechanical treatment strategy for patellofemoral osteoarthritis (OA) that aims to unload the lateral compartment of the joint by translating the patella medially. Our objective was to determine whether a patellar brace can correct patellar kinematics in patients with patellofemoral OA. DESIGN: We assessed the effect of a patellar brace on three-dimensional patellar kinematics (flexion, spin and tilt; proximal, lateral and anterior translation) at sequential, static knee postures, using a validated magnetic resonance imaging (MRI)-based method, in 19 patients with radiographic lateral patellofemoral OA. Differences in kinematics between unbraced and braced conditions were assessed in the unloaded and loaded knee (15% bodyweight load) using hierarchical linear random-effects models. Random slope and quadratic terms were included in the model when significant (P<0.05). RESULTS: Bracing with load caused the patellae to translate 0.46 mm medially (P<0.001), tilt 1.17° medially (P<0.001), spin 0.62° externally (P=0.012) and translate 1.09 mm distally (P<0.001) and 0.47 mm anteriorly (P<0.001) over the range of knee flexion angles studied. Bracing also caused the patellae to extend in early angles of knee flexion (P<0.001). The brace caused similar trends for the unloaded condition, though magnitudes of the changes varied. CONCLUSION: Bracing changed patellar kinematics, but these changes did not appear large enough to be clinically meaningful because no reduction in pain was observed in the parent study.


Subject(s)
Braces , Osteoarthritis/physiopathology , Osteoarthritis/therapy , Patellofemoral Joint/physiopathology , Aged , Biomechanical Phenomena , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Patella/physiopathology
16.
Osteoarthritis Cartilage ; 19(4): 389-98, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21255666

ABSTRACT

OBJECTIVE: To investigate the influence of cumulative lifetime hip joint force on the risk of self-reported medically-diagnosed hip osteoarthritis (OA). DESIGN: Prospective cohort. SETTING: General population. PARTICIPANTS: Members of Canadian Association of Retired Persons, community-dwelling. MAIN OUTCOME: Health-professional diagnosed hip OA, self-reported. METHODS: Exposure data on lifetime physical activity type (occupational, household, sport) and dose (frequency, intensity, duration) was collected in 2005. Subjects were ranked in terms of a 'cumulative peak force index' (CFPI), a measure of lifetime mechanical hip joint force. Multivariable survival analyses were performed to obtain adjusted effects for mean lifetime exposure and during 5-year age periods. RESULTS: Of 2918 subjects aged 45-85, 176 (6.03%) developed hip OA during the 2-year follow up (43 men, 133 women). The highest quintile of mean lifetime hip CPFI (HR 2.32; 95% CI 1.31-4.12), and high hip force in three age periods (35-39, 40-44, 45-49) were independently associated with hip OA. Previous hip injury was an approximate five-fold risk for development of hip OA across all models. In analysis by activity domain (occupation, sport, household), there was a trend (non-significant) for the highest quintile of occupational force, but not sport or household, to be associated with hip OA. CONCLUSIONS: A newly proposed measure of lifetime mechanical hip force was used to estimate the risk of self-reported, medically-diagnosed hip OA. While there are important limitations, this prospective study suggests that lifelong physical activity is generally safe. Very high levels of lifetime force from all domains combined, and in particular from occupational forces, may be important in the etiology of hip OA.


Subject(s)
Motor Activity/physiology , Osteoarthritis, Hip/physiopathology , Stress, Mechanical , Adult , Aged , Body Weight , Cohort Studies , Female , Humans , Male , Middle Aged , Prospective Studies , Risk Factors , Surveys and Questionnaires , Time Factors
17.
J Bone Joint Surg Am ; 92(15): 2557-69, 2010 Nov 03.
Article in English | MEDLINE | ID: mdl-21048174

ABSTRACT

BACKGROUND: Cam deformities cause femoroacetabular impingement and damage the acetabular labral-chondral complex. The aims of this study were to investigate the potential of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) to detect cartilage disease in asymptomatic hips with cam deformities compared with morphologically normal hips, establish whether dGEMRIC could identify advanced disease in hips with positive clinical findings, and establish whether cartilage damage correlated with the severity of the cam deformity. METHODS: Subjects were recruited from a prospective study of individuals with a family history of osteoarthritis and their spouses who served as control subjects. Their symptoms and impingement test results were recorded. Asymptomatic hips with normal radiographic joint-space width were placed in a subgroup according to the presence of a cam deformity and the impingement test result. dGEMRIC was performed on a 3-T system, studying two regions of interest: the anterosuperior aspect of the acetabular cartilage (T1(acet)) and the total femoral and acetabular cartilage (T1(total)). The ratio T1(acet)/T1(total) gave the relative glycosaminoglycan content in the anterosuperior aspect of the acetabular cartilage. The cohort was placed in subgroups by joint morphology, impingement test status, and genetic predisposition; the mean T1 scores were compared, and the alpha angle and T1 were correlated. RESULTS: Of thirty-two subjects (mean age, fifty-two years), nineteen had cam deformities. Hips with a cam deformity had reduced acetabular glycosaminoglycan content compared with normal hips (mean T1(acet)/T1(total), 0.949 and 1.093, respectively; p = 0.0008). Hips with a positive impingement test result had global depletion of glycosaminoglycan compared with hips with a negative result (mean T1(total), 625 ms versus 710 ms; p = 0.0152). T1(acet) inversely correlated with the magnitude of the alpha angle (r = -0.483, p = 0.0038), suggesting that the severity of cartilage damage correlates with the magnitude of the cam deformity. All of these differences occurred irrespective of genetic predisposition. CONCLUSIONS: The dGEMRIC technique can detect cartilage damage in asymptomatic hips with cam deformities and no radiographic evidence of joint space narrowing. This damage correlates with cam deformity severity. Further study of the application of dGEMRIC as an imaging biomarker of early osteoarthritis is justified to validate its prognostic accuracy, identify subjects for clinical trials, and evaluate the effectiveness of surgical procedures.


Subject(s)
Cartilage, Articular/abnormalities , Hip Joint/abnormalities , Magnetic Resonance Imaging/methods , Cartilage, Articular/diagnostic imaging , Contrast Media , Female , Gadolinium DTPA , Hip Joint/diagnostic imaging , Humans , Imaging, Three-Dimensional , Longitudinal Studies , Male , Middle Aged , Prospective Studies , Radiography , Range of Motion, Articular , Reproducibility of Results , Rotation , Statistics, Nonparametric
18.
J Biomech ; 43(10): 1890-7, 2010 Jul 20.
Article in English | MEDLINE | ID: mdl-20413124

ABSTRACT

Studies of three-dimensional patellar kinematics done with little or no applied load may not accurately reflect kinematics at physiological load levels, and may provide different results to those acquired with greater applied loads or in physiologic weightbearing. We report the effect of load magnitude on three-dimensional patellar kinematics (flexion, spin and tilt; proximal, lateral and anterior translation) using a validated, sequential static, MRI-based method. Ten healthy subjects loaded their study knee to 0% (no load), 15% and 30% bodyweight (BW) using a custom designed loading rig. Differences between loading levels were determined as a function of knee flexion for each kinematic parameter using linear hierarchical random-effects models. Quadratic and random slope terms were included in the models when significant. We found that the patellae flexed less with knee flexion at 30% BW load compared to 0% BW load (p<0.001) and 15% BW (p=0.004) load. The patellae showed a slight medial tilt with knee flexion at 30% BW load which was significantly less than the medial tilt seen at 0% BW load (p=0.017) and 15% BW load (p=0.043) with knee flexion. Small but statistically significant differences were also observed for proximal and anterior translation; the patellae were in a more proximal and posterior position at 30% BW load than at 0% BW load (p=0.010 and p=0.005, respectively) and 15% BW load (p<0.001 and p=0.029, respectively). Since differences in three-dimensional patellar kinematics were observed between loading levels, magnitudes of prescribed loads must be considered when designing studies and comparing results between studies.


Subject(s)
Patella/physiology , Adult , Biomechanical Phenomena , Female , Humans , Knee Joint/physiology , Magnetic Resonance Imaging , Male , Patella/anatomy & histology , Patellofemoral Joint/physiology , Range of Motion, Articular , Weight-Bearing
19.
J Exp Biol ; 213(Pt 7): 1035-41, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20228339

ABSTRACT

Coleoid cephalopods, including octopuses, cuttlefish and squid, rely mainly on visual signals when interacting with conspecifics, predators and prey. Presenting visual stimuli, such as models, photographs, mirrors and live conspecifics, can thus provide insight into cephalopod behaviour. These methods, however, have limitations - mirrors and live animals lack experimental control, whereas models and photographs sacrifice motion-based information. Video playback addresses these issues by presenting controlled, moving and realistic stimuli but, to date, video playback has not been used successfully with any cephalopod. Here, we developed a video playback technique for the gloomy octopus (Octopus tetricus) that incorporated recent advances in video technology. We then used this technique to test for personality, which we defined as behavioural differences between individuals that are consistent over time and across ecologically important contexts. We captured wild octopuses and tested them on 3 separate days over a 10 day period. On each test day, subjects were presented with videos of a food item, a novel object and a conspecific. These represented a foraging, novel and threatening context, respectively. A fourth video without a moving stimulus controlled for the playback monitor itself and potential artifacts associated with video playback. Experimental stimuli evoked unambiguous and biologically appropriate responses from the subjects. Furthermore, individuals' responses to the three experimental contexts were highly correlated within a given test day. However, within a given context, individuals behaved inconsistently across the 3 test days. The reordering of ranks suggests that rather than fulfilling the criteria for personality, gloomy octopus show temporal discontinuities, and hence display episodic personality.


Subject(s)
Affect/physiology , Octopodiformes/physiology , Personality/physiology , Videotape Recording , Animals , Physical Stimulation , Principal Component Analysis
20.
Knee ; 17(2): 135-40, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19720534

ABSTRACT

Patellofemoral disorders, such as osteoarthritis and patellofemoral pain, are thought to be associated with abnormal patellar kinematics. However, assessments of three-dimensional patellar kinematics are time consuming and expensive. The aim of this study was to determine whether a single static measure of three-dimensional patellar kinematics provides a surrogate marker for three-dimensional patellar kinematics over a range of flexion angles. We assessed three-dimensional patellar kinematics (flexion, tilt and spin; lateral, anterior and proximal translation) at sequential static angles through approximately 45 degrees of loaded knee flexion in 40 normal subjects using a validated, MRI-based method. The surrogate marker was defined as the static measure at 30 degrees of knee flexion and the pattern of kinematics was defined as the slope of the linear best fit line of each subject's kinematic data. A regression model was used to examine the relationship between the surrogate marker and pattern of kinematics. The surrogate marker predicted 26% of the variance in pattern of patellar flexion (p<0.001), 27% of the variance in pattern of patellar spin (p=0.003), 11% of the variance in pattern of proximal translation (p=0.037) and 39% of the variance in pattern of anterior translation (p<0.001). No relationships were seen between the surrogate marker and tilt or lateral translation. The results suggest that a single measure of patellar parameters at 30 degrees knee flexion is an inadequate surrogate marker of three-dimensional patellar kinematics; therefore, a complete assessment of patellar kinematics, over a range of knee flexion angles, is preferable to adequately assess patterns of patellar kinematics.


Subject(s)
Knee/physiology , Patella/physiology , Patellofemoral Joint/physiology , Biomarkers , Biomechanical Phenomena/physiology , Femur/anatomy & histology , Femur/physiology , Humans , Magnetic Resonance Imaging , Movement/physiology , Patella/anatomy & histology , Range of Motion, Articular , Tibia/anatomy & histology , Tibia/physiology
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