The influence of a calcium sulphate bone void filler on the third-body damage and polyethylene wear of total knee arthroplasty.

OBJECTIVES: Bone void fillers are increasingly being used for dead space management in arthroplasty revision surgery. The aim of this study was to investigate the influence of calcium sulphate bone void filler (CS-BVF) on the damage and wear of total knee arthroplasty using experimental wear simulation. METHODS: A total of 18 fixed-bearing U2 total knee arthroplasty system implants (United Orthopedic Corp., Hsinchu, Taiwan) were used. Implants challenged with CS-BVF were compared with new implants (negative controls) and those intentionally scratched with a diamond stylus (positive controls) representative of severe surface damage (n = 6 for each experimental group). Three million cycles (MC) of experimental simulation were carried out to simulate a walking gait cycle. Wear of the ultra-high-molecular-weight polyethylene (UHMWPE) tibial inserts was measured gravimetrically, and damage to articulating surfaces was assessed using profilometry. RESULTS: There was no significant difference (p > 0.05) between the wear rate of implants challenged with CS-BVF (3.3 mm3/MC (95% confidence interval (CI) 1.8 to 4.8)) and the wear rate of those not challenged (2.8 mm3/MC (95% CI 1.3 to 4.3)). However, scratching the cobalt-chrome (CoCr) significantly (p < 0.001) increased the wear rate (20.6 mm3/MC (95% CI 15.5 to 25.7)). The mean surface roughness of implants challenged with CS-BVF was equivalent to negative controls both after damage simulation (p = 0.98) and at the conclusion of the study (p = 0.28). CONCLUSION: When used close to articulating surfaces, a low-hardness, high-purity CS-BVF had no influence on wear. When trapped between the articulating surfaces of a total knee arthroplasty, CS-BVF did not scratch the surface of CoCr femoral components, nor did it increase the wear of UHMWPE tibial inserts compared with undamaged negative controls.Cite this article: R. M. Cowie, S. S. Aiken, J. J. Cooper, L. M. Jennings. The influence of a calcium sulphate bone void filler on the third-body damage and polyethylene wear of total knee arthroplasty. Bone Joint Res 2019;8:65-72. DOI: 10.1302/2046-3758.82.BJR-2018-0146.R1.

Characteristics of COPD in never-smokers and ever-smokers in the general population: results from the CanCOLD study.

BACKGROUND: There is limited data on the risk factors and phenotypical characteristics associated with spirometrically confirmed COPD in never-smokers in the general population. AIMS: To compare the characteristics associated with COPD by gender and by severity of airway obstruction in never-smokers and in ever-smokers. METHOD: We analysed the data from 5176 adults aged 40 years and older who participated in the initial cross-sectional phase of the population-based, prospective, multisite Canadian Cohort of Obstructive Lung Disease study. Never-smokers were defined as those with a lifetime exposure of <1/20 pack year. Logistic regressions were constructed to evaluate associations for 'mild' and 'moderate-severe' COPD defined by FEV1/FVC <5th centile (lower limits of normal). Analyses were performed using SAS V.9.1 (SAS Institute, Cary, North Carolina, USA). RESULTS: The prevalence of COPD (FEV1/FVC

Exacerbation-like respiratory symptoms in individuals without chronic obstructive pulmonary disease: results from a population-based study.

RATIONALE: Exacerbations of COPD are defined clinically by worsening of chronic respiratory symptoms. Chronic respiratory symptoms are common in the general population. There are no data on the frequency of exacerbation-like events in individuals without spirometric evidence of COPD. AIMS: To determine the occurrence of 'exacerbation-like' events in individuals without airflow limitation, their associated risk factors, healthcare utilisation and social impacts. METHOD: We analysed the cross-sectional data from 5176 people aged 40 years and older who participated in a multisite, population-based study on lung health. The study cohort was stratified into spirometrically defined COPD (post-bronchodilator FEV1/FVC < 0.7) and non-COPD (post bronchodilator FEV1/FVC ≥ 0.7 and without self-reported doctor diagnosis of airway diseases) subgroups and then into those with and without respiratory 'exacerbation-like' events in the past year. RESULTS: Individuals without COPD had half the frequency of 'exacerbation-like' events compared with those with COPD. In the non-COPD group, the independent associations with 'exacerbations' included female gender, presence of wheezing, the use of respiratory medications and self-perceived poor health. In the non-COPD group, those with exacerbations were more likely than those without exacerbations to have poorer health-related quality of life (12-item Short-Form Health Survey), miss social activities (58.5% vs 18.8%), miss work for income (41.5% vs 17.3%) and miss housework (55.6% vs 16.5%), p<0.01 to <0.0001. CONCLUSIONS: Events similar to exacerbations of COPD can occur in individuals without COPD or asthma and are associated with significant health and socioeconomic outcomes. They increase the respiratory burden in the community and may contribute to the false-positive diagnosis of asthma or COPD.

Measuring three-dimensional strain distribution in tendon.

Tendons are tough fibrous tissues that facilitate skeletal movement by transferring muscular force to bone. Studies into the effects of mechanical stress on tendons have shown that these can either accelerate healing or cause tendon injuries depending on the load applied. It is known that local strain magnitude and direction play an important role in tendon remodelling and also failure, and different techniques to study strain distribution have been proposed. Image registration and processing techniques are among the recently employed methods. In this study, a novel three-dimensional image processing technique using the Sheffield Image Registration Toolkit is introduced to study local strain and displacement distribution in tendon. The results show that the local normal strain values in the loading axis are smaller than the global applied load, and fibre sliding was detected as a dominant mechanism for transferring the applied load within tendon. However, results from different samples suggest three distinct modes of deformation during loading, as some show only parallel sliding of fibres in respect to the loading axis, whereas others are twisted or deflected in directions transverse to the loading axis. The proposed 3D image registration method is essential for analysing this out-of-plane movement, which cannot be detected using a standard 2D method.

Canadian prediction equations of spirometric lung function for Caucasian adults 20 to 90 years of age: results from the Canadian Obstructive Lung Disease (COLD) study and the Lung Health Canadian Environment (LHCE) study.

BACKGROUND: Currently, no reference or normative values for spirometry based on a randomly selected Canadian population exist. OBJECTIVE: The aim of the present analysis was to construct spirometric reference values for Canadian adults 20 to 90 years of age by combining data collected from healthy lifelong nonsmokers in two population-based studies. METHOD: Both studies similarly used random population sampling, conducted using validated epidemiological protocols in the Canadian Obstructive Lung Disease study, and the Lung Health Canadian Environment study. Spirometric lung function data were available from 3042 subjects in the COLD study, which was completed in 2009, and from 2571 subjects in the LHCE study completed in 1995. A total of 844 subjects 40 to 90 years of age, and 812 subjects 20 to 44 years of age, were identified as healthy, asymptomatic, lifelong nonsmokers, and provided normative reference values for spirometry. Multiple regression models were constructed separately for Caucasian men and women for the following spirometric parameters: forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC) and FEV(1)/FVC ratio, with covariates of height, sex and age. Comparison with published regression equations showed that the best agreement was obtained from data derived from random populations. RESULTS: The best-fitting regression models for healthy, never-smoking, asymptomatic European-Canadian men and women 20 to 90 years of age were constructed. When age- and height-corrected FEV(1), FVC and FEV(1)/FVC ratio were compared with other spirometry reference studies, mean values were similar, with the closest being derived from population-based studies. CONCLUSION: These spirometry reference equations, derived from randomly selected population-based cohorts with stringently monitored lung function measurements, provide data currently lacking in Canada.

Can age and sex explain the variation in COPD rates across large urban cities? A population study in Canada.

OBJECTIVE: To measure the prevalence of chronic obstructive pulmonary disease (COPD) and determine the effect of age and sex on the variation in prevalence across major cities within the same country and health care system. METHOD: We used the Burden of Obstructive Lung Disease (BOLD) methodology to estimate the prevalence of COPD in adults aged ≥ 40 years in different Canadian cities. The study used interviewer-administered questionnaires on respiratory, smoking and occupational history, medication use and comorbidities. Post-bronchodilator spirometry was used to classify subjects. We determined the prevalence and severity of COPD with and without adjustments for age and sex distribution across different cities. RESULTS: The study population was 3042. Overall, 16.7% (95%CI 14.8-18.7) of study subjects met the criteria for Global Initiative for Chronic Obstructive Lung Disease (GOLD) severity Stage 1 or higher. The prevalence according to the criteria for the lower limits of normal of the ratio forced expiratory volume in 1 second/forced vital capacity was 11.6% (95%CI 9.9-13.3). COPD prevalence varied by severity across site (P = 0.0025). After age-sex adjustment, the variation disappeared (P> 0.16). CONCLUSION: Age and sex differences account for most of the heterogeneity in COPD estimates across large cities within the same country. Adjustments for age and sex are essential in comparing COPD rates across the country.

The neural and vascular effects of killed Su-Streptococcus pyogenes (OK-432) in preterm fetal sheep.

Fetal exposure to inflammatory mediators is associated with a greater risk of brain injury and may cause endothelial dysfunction; however, nearly all the evidence is derived from gram-negative bacteria. Intrapleural injections of OK-432, a killed Su-strain of Streptococcus pyogenes, has been used to treat fetal chylothorax. In this study, we evaluated the neural and cardiovascular effects of OK-432 in preterm fetal sheep (104 +/- 1 days, term 147 days). OK-432 (0.1 mg, n = 6) or saline vehicle (n = 7) was infused in the fetal pleura, and fetuses were monitored for 7 days. Blood samples were taken routinely for plasma nitrite measurement. Fetal brains were taken for histological assessment at the end of the experiment. Between 3 and 7 h postinjection, OK-432 administration was associated with transient suppression of fetal body and breathing movements and electtroencephalogram activity (P < 0.05), increased carotid and femoral vascular resistance (P < 0.05), but no change in blood pressure. Brain activity and behavior then returned to normal except in one fetus that developed seizures. OK-432 fetuses showed progressive, sustained vasodilatation (P < 0.05), with lower blood pressure after 4 days (P < 0.05), but normal heart rate. There were no changes in plasma nitrite levels. Histological studies showed bilateral infarction in the dorsal limb of the hippocampus of the fetus that developed seizures, but no injury in other fetuses. We conclude that a single low-dose injection of OK-432 can be associated with risk of focal cerebral injury in the preterm fetus and chronic central and peripheral vasodilatation that does not appear to be mediated by nitric oxide.

Assessment and management of patients with chronic cough by Certified Respiratory Educators: a randomized controlled trial.

BACKGROUND: The value of other health care professionals is increasingly being recognized to compensate for the shortage of physicians in Canada. Chronic cough is one of the most common reasons for consultation with a respirologist. In the present study, a prospective, randomized, controlled study was undertaken to determine whether Certified Respiratory Educators (CREs) could manage screened patients with chronic cough as effectively as respirologists. METHODS: An eight-week, prospective, parallel-design, randomized, controlled trial of the management of chronic cough patients was conducted. Patients were screened to exclude those with potentially life-threatening conditions. The primary outcome was the number of patients whose cough resolved or subjectively improved. RESULTS: A total of 198 patients were randomly assigned, and eight-week data were available on 151 patients. Mean age of the patients was 49.8+/-13.4 years, 70.2% were female and median cough duration was 16 months. The screening process was effective and referral wait times decreased from a median of two months to less than four weeks (P<0.0001). The educators averaged 4.9 contacts per patient compared with 2.7 by the physicians over the eight-week study period (P<0.0001). Most patients had had multiple therapeutic trials before referral. Cough resolved or improved in two-thirds of the patients at eight weeks; however, more patients showed improvement in the educator arm than in the physician arm, P<0.02. Cough-specific quality of life improved similarly in the two study arms at eight weeks (physician arm: 61.5+/-14.1 to 52.6+/-14.4, P<0.0001; CRE arm: 58.1+/-14.9 to 50.0+/-15.8, P=0.0003). CONCLUSIONS: CREs can safely and effectively assess, as well as appropriately treat, screened patients with chronic cough with a resultant reduction in wait times.

Craniocervical instability in an infant with partial sacral agenesis.

UNLABELLED: Sacral agenesis is an uncommon condition characterised by total or partial absence of the sacrum. The association of this condition with craniocervical junction abnormalities is extremely rare. CASE REPORT: We describe a 3-year-old girl who, at the age of 8 months, while being investigated for short stature, was found to have significant craniocervical instability associated with anomalies of the odontoid peg. In addition to this she had partial sacral agenesis but genetic tests showed a normal karyotype. Due to the inherent difficulty of surgical fixation and immobilisation in an infant of her age, she was managed conservatively in a soft cervical orthosis. At the age of three years, surgery for decompression and stabilisation was deemed necessary due to the onset of neurological morbidity. CONCLUSION: The authors describe this extremely rare association and discuss the difficulties faced while deciding the optimum surgical strategy for managing such young children with craniocervical instability.

Blood metabolite levels in normal and handicapped pied flycatchers rearing broods of different sizes.

We measured levels of select metabolites (glucose, triglycerides, free fatty acids, glycerol, uric acid) and corticosterone in the blood plasma of adult pied flycatchers Ficedula hypoleuca while they were rearing broods whose sizes were modified experimentally. We also made it more difficult than normal for some pairs of birds to forage by removing certain wing and tail feathers (handicapping them). Both procedures have been shown previously to change parental workload. We did this in order to determine if the birds alter their use of nutrients in response to differences in their workload. Metabolite levels were not influenced by handicapping or brood size. However, the concentration of free fatty acids in the plasma of females and of triglycerides in the plasma of males was directly related to the frequency with which the adults fed their nestlings. These findings suggest that the two sexes have different ways of coping with the work associated with rearing the brood: females apparently undergo brief daily fasts while feeding their chicks, whereas males take more time to feed themselves while providing food for their young, and spend more time doing so as their workload increases. The flycatchers exhibited high concentrations of uric acid and corticosterone in the blood plasma; corticosterone and glycerol were positively correlated in females; and corticosterone and triglyceride levels were negatively correlated in males; all of which suggest that gluconeogenesis provides some of the energy required for their parental activities.

ASR for emotional speech: clarifying the issues and enhancing performance.

There are multiple reasons to expect that recognising the verbal content of emotional speech will be a difficult problem, and recognition rates reported in the literature are in fact low. Including information about prosody improves recognition rate for emotions simulated by actors, but its relevance to the freer patterns of spontaneous speech is unproven. This paper shows that recognition rate for spontaneous emotionally coloured speech can be improved by using a language model based on increased representation of emotional utterances. The models are derived by adapting an already existing corpus, the British National Corpus (BNC). An emotional lexicon is used to identify emotionally coloured words, and sentences containing these words are recombined with the BNC to form a corpus with a raised proportion of emotional material. Using a language model based on that technique improves recognition rate by about 20%.

Tuberculosis in Calgary, Canada, 1995-2002: site of disease and drug susceptibility.

SETTING: A centre managing all tuberculosis (TB) cases in the population of the Calgary region in Canada. OBJECTIVE: To facilitate the diagnosis and management of TB by examining the distribution of TB by site of disease and the prevalence and pattern of drug-resistant Mycobacterium tuberculosis in a north American setting. DESIGN: A retrospective analysis of data collected at the time of diagnosis of all TB cases recorded during the 8-year period 1995-2002. Data collected included demographic information, site of disease, method of diagnosis and M. tuberculosis drug susceptibility. RESULTS: During the 8-year period, 435 cases of TB were diagnosed: 49% had exclusively extra-pulmonary disease. Lymph node disease (usually cervical) accounted for 44% of the extra-pulmonary cases. A culture of M. tuberculosis resistant to at least one first-line anti-tuberculosis drug was detected in 16% of the initial isolates. All of the resistant strains were found in foreign-born patients and resistance was more common in patients from Asia (19%) and in previously treated patients (26%). CONCLUSION: Extra-pulmonary TB is common in the foreign-born population in the Calgary region, and this pattern may be more widespread than is realised. Drug-resistant strains of TB were more common in foreign-born and previously treated patients.

New proposals for training in neurosurgery.

The rapidly evolving changes in working patterns, career structure and the regulation of training of doctors have provided an ideal opportunity for proposals to improve the programme for the training of neurosurgeons. The Education and Training Committee of the Society of British Neurological Surgeons (D.G. Hardy, A. J. W. Steers, N. T. Gurusinghe, P. M. Foy, P. van Hille, R. A. Cowie, H. A. Crockard, O. Sparrow and S. Burn) has, in recent months, worked closely with the Specialist Advisory Committee (SAC) in neurosurgery, Department of Health (Modernizing Medical Careers Group, H. A. Crockard, A. Havers, T. Hobbs) and colleagues from the major neuroscience specialties to develop a new programme based on a 'Common Stem' approach. This article describes the principles of the programme. The proposals have received approval by the Council of the SBNS, the Presidents of the four Surgical Royal Colleges and the Senate of Surgery.

PicSOr: an objective test of perceptual skill that predicts laparoscopic technical skill in three initial studies of laparoscopic performance.

BACKGROUND: Laparoscopic surgery requires surgeons to infer the shape of 3-D structures, such as the internal organs of patients, from 2-D displays on a video monitor. Recent evidence indicates that the issue is not resolved by the use of contemporary 3-D camera systems. It is therefore crucial to find ways of measuring differences in aptitude for recovering 3-D structure from 2-D images, and assessing its impact on performance. Our aim was to test empirically for a relationship between laparoscopic ability and the perceptual skill of recovering information about 3-D structures from 2-D monitor displays. METHODS: Participants in three studies completed a simulated laparoscopic cutting task as well as the Pictorial Surface Orientation (PicSOr)3 Test. In studies 1 (n = 48) and 2 (n = 32) both groups were laparoscopic novices, and in study 3 (n = 34) 18 of the participants were experienced laparoscopic surgeons. FINDINGS: All three studies showed that PicSOr consistently predicted the laparoscopic performance of participants on the laparoscopic cutting task (study 1, r = 0.5, p < 0.0003; study 2, r = 0.5, p < 0.004; and study 3, r = 0.42, p = 0.017). Furthermore, it was also a significant predictor of laparoscopic surgeons' performance (r = 0.54, p = 0.047). INTERPRETATIONS: This is the first objective perceptual psychometric test to reliably predict laparoscopic technical skills. PicSOr provides a tool for assessing which trainees have the potential to learn minimal access surgery.

Identification and genetic characterisation of Giardia and Cryptosporidium strains in humans and dairy cattle in the Waikato Region of New Zealand.

Giardia intestinalis and Cryptosporidium parvum are commonly acquired waterborne parasites but little is known about their transmission cycles with regard to humans and animals. Faecal samples were collected over two time periods within the Waikato region of New Zealand from dairy cattle and humans and all positive isolates were genotyped. Of the 724 faecal specimens examined (354 cows, 304 calves and 66 humans), 16 cows, 32 calves and 5 humans were positive for G. intestinalis. Phylogenetic group 1 was found in 26 G. intestinalis positive dairy cattle with 22 being group 2. One G. intestinalis positive human isolate was group 1 and four were group 2. Of the 724 faecal specimens examined two cows, 33 calves and 66 human specimens were positive for C. parvum. All 35 C. parvum positive dairy cattle exhibited the bovine genotype while the 66 positive humans showed a seasonal shift in the prevalent genotype with the bovine dominating the spring (100%) and the human dominating the late summer period (96%).

Prosodic characteristics of skilled reading: fluency and expressiveness in 8-10-year-old readers.

Statistical methods of describing prosody were used to study fluency, expressiveness and their relationship among 8-10-year-old readers. 67 children were rated on fluency and expressiveness. The two were partially independent in the full sample: expressiveness rarely occurred without fluency, but fluency occurred without expressiveness. A balanced subsample of 24 was selected for closer instrumental and statistical analysis. There were robust relationships between fluency and measures associated with temporal organization.between expressiveness and variables associated with pitch mobility; and Interactions indicated that the relationships were not simple. Differences between groups depended on sentence content and position-expressive readers distinguished sentences more sharply according to content, and the groups diverged on some measures as the passage progressed. Also, measures associated primarily with either fluency or expression often showed secondary sensitivity to the other: temporal organization was associated with fluency, but worsened over time among inexpressive readers; and readers who were both fluent and expressive were distinctive in several respects. Some measures offer a basis for rules aimed at assigning individuals to skill categories, particularly the magnitude of pitch movements and reading time per syllable. The rules distinguish well among readers who were either at one of the extremes of skill, or fluent but inexpressive; it is harder to discriminate among the other readers (who have mixed skill patterns). The effects suggest psychological hypotheses about the underlying mechanisms.

The epidemiology of tuberculosis among foreign-born persons in Alberta, Canada, 1989-1998: identification of high risk groups.

BACKGROUND: To date, there have been no comprehensive epidemiological studies in Canada of the incidence rates of tuberculosis among foreign-born persons. Accurate rate estimates are needed to develop cost-effective strategies for the prevention, control, and ultimate elimination of tuberculosis. METHODS: Most new immigrants to Canada settle in one of four provinces: Ontario, British Columbia, Quebec and Alberta. Data from the provincial reporting system for tuberculosis, from Statistics Canada censuses and population estimates of Treaty Status Indians provided by the Department of Indian and Northern Affairs Canada, were used to estimate the rate of tuberculosis in Alberta's Canadian-born and foreign-born population between 1989 and 1998. RESULTS: Age-adjusted tuberculosis case rates per 100,000 person-years were 19.4 and 61.9 in the foreign-born and Canadian-born Treaty Indians-approximately 10 times and 30 times, respectively, higher than the rate in the remainder of the Canadian-born population (2.1/100,000 person-years). Age-specific rates in male and female foreign-born persons were highest at ages 15-34 and > or = 65 years, whereas rates in Canadian-born non-Treaty and Treaty males and females increased incrementally, with a single peak at > or = 65 years. Tuberculosis case rates in the foreign-born varied significantly according to World Bank region and country of birth. By far the highest rates were seen in immigrants to Canada from Asia, in particular Vietnam, the Philippines, China, Hong Kong and India. Most (90%) tuberculosis patients from these countries had not been identified as requiring medical surveillance in Canada after arrival. CONCLUSION: Immigrants to Alberta from Asia and Treaty Status Indians are at high risk for tuberculosis. Physicians in Alberta who care for foreign-born persons should be aware that their patients are at increased risk for tuberculosis, even if they have been medically cleared during the legal immigration process.

Asthma education and management programs in Canada.

OBJECTIVE: To establish the number and type of asthma patient education programs throughout Canada. DESIGN: National survey. SETTING: Canada. METHODS: Over a three-year period, contact was made with individuals and groups offering educational services for patients with asthma. Education given as part of a physician's consultation or a pharmacist's dispensing of medications for asthma was not considered a patient education program for the purposes of the survey. Contact was initially established by asking staff from well known asthma programs to provide lists of other such programs in their provinces or regions. Asthma programs were also identified from notices presented at Canada's Third and Fourth National Conferences on Asthma and Education. Lung associations, lay organizations and industry representatives affiliated with the Canadian Network for Asthma Care helped to supplement the list. Once identified, each patient education program was contacted by telephone and by mail to complete a 26-item questionnaire about their program. The province of Quebec was not included in the survey because it already had a province-wide, structured asthma education program and register. RESULTS: Seventy-four asthma education and management programs were identified outside Quebec. Staff in these programs were registered nurses (n=46), respiratory therapists (n=48) and other health professionals (n=21). Forty-one programs stated that at least one member of their staff had been trained as an asthma educator. In 71 programs, the initial patient encounter was of at least one hour's duration. Physician referral was required by 41 programs. The province of Quebec has a joint asthma education program provided by 114 asthma education centres throughout the province under the umbrella of the Quebec Asthma Education Network (QAEN). This comprehensive program is provided in hospitals and community centres by specialized educators - nurses, pharmacists or respiratory therapists - to patients referred by their physicians. CONCLUSIONS: A three-year search for asthma education programs in Canada identified 74 patient education programs (outside Quebec) for an asthma population estimated to exceed 1.2 million. For the province of Quebec, an integrated asthma education program is provided through a network of 114 education centres - the QAEN. The present survey shows that there has been progress in establishing asthma education programs in Canada, although there are significant regional differences in the availability of such programs.