No change in avilamycin (Surmax® Premix) minimum inhibitory concentration for Clostridium perfringens isolates recovered from poultry up to 7 years post-approval in Canada.

BACKGROUND: Clostridium perfringens, the causative agent of necrotic enteritis (NE) in chickens, has an enormous economic impact on global broiler production. The non-medically important antibiotic avilamycin was approved in Canada in 2014 to prevent and control NE in broiler chickens. OBJECTIVES: To compare avilamycin susceptibility in C. perfringens isolates collected pre- and 7 years post-avilamycin approval in Canada and determine the avilamycin resistance mutation frequency rate in C. perfringens. METHODS: The MICs of avilamycin were determined for 89 strains of C. perfringens recovered from clinically relevant NE field cases pre-avilamycin approval between 2003 and 2013 (n = 50) and post-avilamycin approval between 2014 and 2021 (n = 39) across Canada. For determining the mutant prevention concentration (MPC) of avilamycin for C. perfringens strains, a strain with avilamycin MIC of 1 mg/L was randomly selected. RESULTS: MIC studies showed no difference in avilamycin susceptibility in pre-avilamycin and post-avilamycin isolates (MIC50/90: pre-avilamycin approval 2/2 mg/L and post-avilamycin approval 1/2 mg/L). The MPC was 8 × MIC (8 mg/L) for the selected strain. CONCLUSIONS: These findings suggest that the susceptibility of C. perfringens strains to avilamycin was not impacted by its continued use in the 7 years following its approval in Canada. Avilamycin, a non-medically important antibiotic, poses no threat to human health regarding cross-resistance or co-selection of other medically important antibiotics. These factors make avilamycin an appropriate choice for continued use in broiler chickens to prevent and control NE without increased antimicrobial resistance concerns.

Forecasting Pathogen Dynamics with Bayesian Model-Averaging: Application to Xylella fastidiosa.

Forecasting invasive-pathogen dynamics is paramount to anticipate eradication and containment strategies. Such predictions can be obtained using a model grounded on partial differential equations (PDE; often exploited to model invasions) and fitted to surveillance data. This framework allows the construction of phenomenological but concise models relying on mechanistic hypotheses and real observations. However, it may lead to models with overly rigid behavior and possible data-model mismatches. Hence, to avoid drawing a forecast grounded on a single PDE-based model that would be prone to errors, we propose to apply Bayesian model averaging (BMA), which allows us to account for both parameter and model uncertainties. Thus, we propose a set of different competing PDE-based models for representing the pathogen dynamics, we use an adaptive multiple importance sampling algorithm (AMIS) to estimate parameters of each competing model from surveillance data in a mechanistic-statistical framework, we evaluate the posterior probabilities of models by comparing different approaches proposed in the literature, and we apply BMA to draw posterior distributions of parameters and a posterior forecast of the pathogen dynamics. This approach is applied to predict the extent of Xylella fastidiosa in South Corsica, France, a phytopathogenic bacterium detected in situ in Europe less than 10 years ago (Italy 2013, France 2015). Separating data into training and validation sets, we show that the BMA forecast outperforms competing forecast approaches.

Systematic review of imaging comparisons of spinal alignment among standing positions in healthy adolescents or adolescents with idiopathic scoliosis: SOSORT 2023 award winner.

PURPOSE: Clinicians detect scoliosis worsening over time using frequent radiographs during growth. Arms must be elevated when capturing sagittal radiographs to visualize the vertebrae, and this may affect the sagittal angles. The aim was to systematically review the published evidence of the effect of arm positions used during radiography on spinal alignment parameters in healthy participants and those with AIS. METHODS: Design was registered in PROSPERO (CRD42022347494). A search strategy was run in Medline, Embase, CINAHL, and Web of Science. Healthy participants ≥ 10 years old and participants with AIS between 10 and 18 years old, with Cobb angles > 10° were included. Study quality was assessed using the Appraisal tool for Cross-Sectional Studies (AXIS). Meta-analysis was performed where possible. RESULTS: Overall, 1332 abstracts and 33 full texts were screened. Data was extracted from 7 included studies. The most common positions were habitual standing, fists on clavicle, and active (arms raised unsupported). Kyphosis, lordosis, and sagittal vertical axis (SVA) were most measured. Meta-analysis showed significantly decreased kyphosis (SMD = 0.78, 95%CI 0.48, 1.09) and increased lordosis (SMD = - 1.21, 95%CI - 1.58, - 0.85) when clavicle was compared to standing. Significant posterior shifts in SVA were shown in clavicle compared to standing (MD = 30.59 mm, 95%CI 23.91, 37.27) and active compared to clavicle (MD = - 2.01 mm, 95%CI - 3.38, - 0.64). Cobb angles and rotation were rarely studied (1 study). CONCLUSION: Meta-analysis evidence showed elevated arm positions modify sagittal measurements compared to standing. Most studies did not report on all relevant parameters. It is unclear which position best represent habitual standing.

Prediction of future curve angle using prior radiographs in previously untreated idiopathic scoliosis: natural history from age 6 to after the end of growth (SOSORT 2022 award winner).

PURPOSE: Treatment selection for idiopathic scoliosis is informed by the risk of curve progression. Previous models predicting curve progression lacked validation, did not include the full growth/severity spectrum or included treated patients. The objective was to develop and validate models to predict future curve angles using clinical data collected only at, or both at and prior to, an initial specialist consultation in idiopathic scoliosis. METHODS: This is an analysis of 2317 patients with idiopathic scoliosis between 6 and 25 years old. Patients were previously untreated and provided at least one prior radiograph prospectively collected at first consult. Radiographs were re-measured blinded to the predicted outcome: the maximum Cobb angle on the last radiograph while untreated. Linear mixed-effect models were used to examine the effect of data from the first available visit (age, sex, maximum Cobb angle, Risser, and curve type) and from other visits while untreated (maximum Cobb angle) and time (from the first available radiograph to prediction) on the Cobb angle outcome. Interactions of the first available angle with time, of time with sex, and time with Risser were also tested. RESULTS: We included 2317 patients (83% of females) with 3255 prior X-rays where 71% had 1, 21.1% had 2, and 7.5% had 3 or more. Mean age was 13.9 ± 2.2yrs and 81% had AIS. Curve types were: 50% double, 26% lumbar/thoracolumbar-lumbar, 16% thoracic, and 8% other. Cobb angle at the first available X-ray was 20 ± 10° (0-80) vs 29 ± 13° (6-122) at the outcome visit separated by 28 ± 22mths. In the model using data at and prior to the specialist consult, larger values of the following variables predicted larger future curves: first available Cobb angle, Cobb angle on other previous X-ray, and time (with Time2 and Time3) to the target prediction. Larger values on the following variables predicted a smaller future Cobb angle: Risser and age at the first available X-ray, time*Risser and time*female sex interactions. Cross-validation found a median error of 4.5o with 84% predicted within 10°. Similarly, the model using only data from the first specialist consult had a median error of 5.5o with 80% of cases within 10° and included: maximum Cobb angle at first specialist consult, Time, Time2, age, curve type, and both interactions. CONCLUSIONS: The models can help clinicians predict how much curves would progress without treatment at future timepoints of their choice using simple variables. Predictions can inform treatment prescription or show families why no treatment is recommended. The nonlinear effects of time account for the rapid increase in curve angle at the beginning of growth and the slowed progression after maturity. These validated models predicted future Cobb angle with good accuracy in untreated idiopathic scoliosis over the full growth spectrum.

Reported non-compliance with pre-donation screening among blood donors in Québec, Canada: A focus on the 3-month deferral for men who have sex with men.

BACKGROUND AND OBJECTIVES: In Québec (Canada), the donation deferral for men who have sex with men (MSM) has recently been shortened to 3 months. Whether this change impacted compliance with pre-donation screening is unknown. We assessed compliance with the disclosure of male-to-male sex and other behavioural risk factors for HIV amid this change. MATERIALS AND METHODS: Québec residents who donated from 14 July 2020 to 30 November 2020 were invited to participate in an online survey. Donors were informed that the survey was optional and anonymous. Survey questions were those used for routine pre-donation screening. Rates of reported non-compliance were weighted based on several characteristics. RESULTS: Of 21,918 contacted donors, 7113 (32.45%) participated. Among male participants (N = 3347), six (0.27% [95% confidence interval (CI) = 0.09%-0.44%]) were not compliant with a 3-month MSM deferral. Among female participants (N = 3766), two (0.06% [95% CI = 0.00%-0.13%]) were not compliant with a 3-month deferral for sex with a man who had male-to-male sex ≤12 months. Other risk factors exhibited similar or lower rates of reported non-compliance. CONCLUSION: Reported non-compliance with a 3-month MSM deferral and the disclosure of other HIV behavioural risk factors was low. These results warrant the investigation of behavioural donor risk assessment approaches to further improve the inclusiveness of blood donation.

Use of machine learning to select texture features in investigating the effects of axial loading on T2-maps from magnetic resonance imaging of the lumbar discs.

BACKGROUND: Recent advances in texture analysis and machine learning offer new opportunities to improve the application of imaging to intervertebral disc biomechanics. This study employed texture analysis and machine learning on MRIs to investigate the lumbar disc's response to loading. METHODS: Thirty-five volunteers (30 (SD 11) yrs.) with and without chronic back pain spent 20 min lying in a relaxed unloaded supine position, followed by 20 min loaded in compression, and then 20 min with traction applied. T2-weighted MR images were acquired during the last 5 min of each loading condition. Custom image analysis software was used to segment discs from adjacent tissues semi-automatically and segment each disc into the nucleus, anterior and posterior annulus automatically. A grey-level, co-occurrence matrix with one to four pixels offset in four directions (0°, 45°, 90° and 135°) was then constructed (320 feature/tissue). The Random Forest Algorithm was used to select the most promising classifiers. Linear mixed-effect models and Cohen's d compared loading conditions. FINDINGS: All statistically significant differences (p < 0.001) were observed in the nucleus and posterior annulus in the 135° offset direction at the L4-5 level between lumbar compression and traction. Correlation (P2-Offset, P4-Offset) and information measure of correlation 1 (P3-Offset, P4-Offset) detected significant changes in the nucleus. Statistically significant changes were also observed for homogeneity (P2-Offset, P3-Offset), contrast (P2-Offset), and difference variance (P4-Offset) of the posterior annulus. INTERPRETATION: MRI textural features may have the potential of identifying the disc's response to loading, particularly in the nucleus and posterior annulus, which appear most sensitive to loading. LEVEL OF EVIDENCE: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

The classification of scoliosis braces developed by SOSORT with SRS, ISPO, and POSNA and approved by ESPRM.

PURPOSE: Studies have shown that bracing is an effective treatment for patients with idiopathic scoliosis. According to the current classification, almost all braces fall in the thoracolumbosacral orthosis (TLSO) category. Consequently, the generalization of scientific results is either impossible or misleading. This study aims to produce a classification of the brace types. METHODS: Four scientific societies (SOSORT, SRS, ISPO, and POSNA) invited all their members to be part of the study. Six level 1 experts developed the initial classifications. At a consensus meeting with 26 other experts and societies' officials, thematic analysis and general discussion allowed to define the classification (minimum 80% agreement). The classification was applied to the braces published in the literature and officially approved by the 4 scientific societies and by ESPRM. RESULTS: The classification is based on the following classificatory items: anatomy (CTLSO, TLSO, LSO), rigidity (very rigid, rigid, elastic), primary corrective plane (frontal, sagittal, transverse, frontal & sagittal, frontal & transverse, sagittal & transverse, three-dimensional), construction-valves (monocot, bivalve, multisegmented), construction-closure (dorsal, lateral, ventral), and primary action (bending, detorsion, elongation, movement, push-up, three points). The experts developed a definition for each item and were able to classify the 15 published braces into nine groups. CONCLUSION: The classification is based on the best current expertise (the lowest level of evidence). Experts recognize that this is the first edition and will change with future understanding and research. The broad application of this classification could have value for brace research, education, clinical practice, and growth in this field.

Reliability of measurements of a reflection coefficient index to indicate spinal bone strength on adolescents with idiopathic scoliosis (AIS): a pilot study.

PURPOSE: To investigate the test-retest, intra- and inter-rater reliabilities of an ultrasound (US) reflection coefficient (RC) index measured in a lumbar vertebra to reflect bone strength on children with AIS. METHODS: Fifty-eight participants (47F; 11M) were scanned by an US imager in standing position. Twenty-four were scanned twice for a test-retest study. The RC index measures the US signal reflected from L5 to indicate bone strength. Five measurements were obtained using three different methods: (i) the maximum RC (MRC) values on the left and right sides, (ii) the average RC (ARC) values on left and right sides, and (iii) the combined average RC (CARC) from both sides. Only rater 1 measured the 24 repeated US scans once. Raters 1 and 2 measured the RC index twice on all 58 images in 1 week apart. The intraclass correlation coefficient ICC [3, 1] for test-retest and ICC [2, 1] for intra- and inter-rater reliabilities as well as the standard error of measurements (SEM) were reported. RESULTS: The means of scan 1 versus scan 2 were 0.16 ± 0.08 versus 0.16 ± 0.07 for left-MRC, 0.17 ± 0.11 versus 0.18 ± 0.11 for right-MRC, 0.08 ± 0.04 versus 0.09 ± 0.04 for left-ARC, 0.09 ± 0.04 versus 0.09 ± 0.05 for right-ARC and 0.08 ± 0.04 versus 0.09 ± 0.03 for CARC and all ICC[3, 1] ≥ 0.77. Among these 5 approaches, the CARC provided the best intra-rater and inter-rater reliabilities with ICC [2, 1] ≥ 0.84 and SEM ≤ 0.01. CONCLUSIONS: The RC index could be measured repeatably and reliably. The high RC value may reduce the risk of progression of scoliosis.

Long-Term Athlete Development: Seasonal and Longitudinal Fitness Changes in Female University Rugby Players.

ABSTRACT: Falk Neto, JH, Parent, E, and Kennedy, MD. Long-term athlete development: Seasonal and longitudinal fitness changes in female university rugby players. J Strength Cond Res 35(12): 3459-3465, 2021-The Long-Term Athlete Development model is used by organizations to determine the expected improvements from athletes at different stages of their careers. For female rugby athletes, university sports should provide continued support for athlete development during the Training to Perform stage (18-21 years old). However, little evidence exists for longitudinal changes across years of participation in university sports in this group. The purpose of this study was to assess changes in anthropometric and fitness characteristics in female university rugby players across different seasons. Seventeen players were divided into forwards (n = 9, 21.1 ± 2.6 years) and backs (n = 8, 19.62 ± 0.9 years) and assessed across 5 points over 3 years: preseason 1, postseason 1, preseason 2, postseason 2, and preseason 3. Anthropometric (height, body mass, and body mass index) and performance measurements (grip strength, flexibility, trunk muscular endurance, upper-body muscular endurance, 40-m sprint, vertical jump, and 20-m shuttle run) were collected. V̇o2max was higher at preseason 2 compared with postseason 1 (p = 0.02), postseason 2 (p = 0.01), and preseason 3 (p = 0.015), and trunk muscular endurance was higher at preseason 3 (p = 0.02). Performance in the first 5 m of the sprint test decreased at postseason 1 (p = 0.018) and preseason 2 (p = 0.016) when compared with preseason 1. The results indicate that these female athletes did not improve their fitness across the Training to Perform stage when participating in university sports. These female rugby players likely developed their fitness at earlier stages and, at this stage, already possessed well-developed fitness levels, which were merely maintained throughout years.

Does image guidance decrease pedicle screw-related complications in surgical treatment of adolescent idiopathic scoliosis: a systematic review update and meta-analysis.

PURPOSE: Surgical treatment of severe adolescent idiopathic scoliosis (AIS) with posterior spinal instrumentation and fusion with pedicle screws is common, requiring careful screw insertion to prevent pedicle breaches and neurologic complications. Image guidance has been suggested to improve breach rates, though the radiation risk for AIS precludes its common usage. The purpose of this systematic review and meta-analysis was to compare the breach rates and screw-related complications for AIS patients undergoing spine surgery with pedicle screws between freehand screw insertion and image guidance methods. METHODS: A comprehensive search of MEDLINE, EMBASE, CINAHL, CENTRAL and Web of Science databases was conducted. Two reviewers independently screened abstracts, full-texts, extracted data and performed risk of bias assessment using the QUIPS quality appraisal tool. Level of evidence summary statements were formulated based on consistency and quality of reporting. RESULTS: Ninety-four studies were found, with 18 studies of moderate risk of bias or better. Moderate evidence from two head-to-head studies shows CT guidance has lower breach rates than freehand methods (OR 0.28 [0.20-0.40, I2 = 1%]), with no complications in either study. From individual studies, moderate evidence showed lower breach rates for image guidance versus freehand methods (13%, I2 = 98% vs. 20%, I2 = 95%). Complication rates were conflicting (0-1.6% for image guidance, 0-1.7% for freehand). Moderate evidence showed increased surgical time for image guidance versus freehand (257.7 min vs. 226.8 min). CONCLUSIONS: Meta-analyzed breach rates show moderate evidence of decreased breaches with CT navigation compared with freehand methods. Complication rates remain unknown due to the low complication rates from small sample sizes. These slides can be retrieved under Electronic Supplementary Material.

Dating and localizing an invasion from post-introduction data and a coupled reaction-diffusion-absorption model.

Invasion of new territories by alien organisms is of primary concern for environmental and health agencies and has been a core topic in mathematical modeling, in particular in the intents of reconstructing the past dynamics of the alien organisms and predicting their future spatial extents. Partial differential equations offer a rich and flexible modeling framework that has been applied to a large number of invasions. In this article, we are specifically interested in dating and localizing the introduction that led to an invasion using mathematical modeling, post-introduction data and an adequate statistical inference procedure. We adopt a mechanistic-statistical approach grounded on a coupled reaction-diffusion-absorption model representing the dynamics of an organism in an heterogeneous domain with respect to growth. Initial conditions (including the date and site of the introduction) and model parameters related to diffusion, reproduction and mortality are jointly estimated in the Bayesian framework by using an adaptive importance sampling algorithm. This framework is applied to the invasion of Xylella fastidiosa, a phytopathogenic bacterium detected in South Corsica in 2015, France.

Differential patient responses to spinal manipulative therapy and their relation to spinal degeneration and post-treatment changes in disc diffusion.

PURPOSE: Our prior study revealed that people with non-specific low back pain (LBP) who self-reported a > 30% improvement in disability after SMT demonstrated significant post-treatment improvements in spinal stiffness, dynamic muscle thickness and disc diffusion, while those not having self-reported improvement did not have these objective changes. The mechanism underlying this differential post-SMT response remains unknown. This exploratory secondary analysis aimed to determine whether persons with non-specific LBP who respond to spinal SMT have unique lumbar magnetic resonance imaging (MRI) findings compared to SMT non-responders. METHODS: Thirty-two participants with non-specific LBP received lumbar MRI before and after SMT on Day 1. Resulting images were assessed for facet degeneration, disc degeneration, Modic changes and apparent diffusion coefficient (ADC). SMT was provided again on Day 4 without imaging. SMT responders were classified as having a ≥ 30% reduction in their modified Oswestry disability index at Day 7. Baseline MRI findings between responders and non-responders were compared. The associations between SMT responder status and the presence/absence of post-SMT increases in ADC values of discs associated with painful/non-painful segments as determined by palpation were calculated. In this secondary analysis, a statistical trend was considered as a P value between 0.05 and 0.10. RESULTS: Although there was no significant between-group difference in all spinal degenerative features (e.g. Modic changes), SMT responders tended to have a lower prevalence of severely degenerated facets (P = 0.05) and higher baseline ADC values at the L4-5 disc when compared to SMT non-responders (P = 0.09). Post hoc analyses revealed that 180 patients per group should have been recruited to find significant between-group differences in the two features. SMT responders were also characterized by significant increases in post-SMT ADC values at discs associated with painful segments identified by palpation (P < 0.01). CONCLUSIONS: The current secondary analysis suggests that the spines of SMT responders appear to differ from non-responders with respect to degeneration changes in posterior joints and disc diffusion. Although this analysis was preliminary, it provides a new direction to investigate the mechanisms underlying SMT and the existence of discrete forms of treatment-specific LBP. These slides can be retrieved under Electronic Supplementary Material.

Reliability of a new loaded rolling wheel system for measuring spinal stiffness in asymptomatic participants.

BACKGROUND: Few, if any, patient reported symptoms have been shown to be related to objective measures of spine function. Recently, patient-reported measures of disability following spinal manipulative therapy have been associated with an immediate decrease in spinal stiffness obtained by instrumented L3 indentation. Given this novel relation, we anticipate that stiffness measures obtained from locations in addition to L3 may yield valuable information. As such, our research team has developed a new technique to acquire stiffness data continuously over an entire spinal region. The reliability of stiffness measurements obtained by this new technique has yet to be quantified. METHODS: Continuous stiffness testing employs a weighted roller that moves uninterrupted over the spine while measuring the resulting spinal deflection along a subject-specific, laser-defined trajectory. A volunteer sample of asymptomatic participants were assessed in 2 sessions occurring 1 to 4 days apart, with each session scheduled at the same time of day. Each session consisted of 3 trials each beginning at a baseline of ~ 17 N then progressing to a maximally tolerable load as defined from pre-test familiarization trials (~ 61, 72 or 83 N). Reliability was evaluated with the intraclass correlation coefficient, the standard error of measurement and Bland & Altman analysis. RESULTS: A total of 17 asymptomatic participants (mean age 29.2 +/- 6 years, 53% female) took part in the study. Overall, the within and between-session reliability of lumbar spine stiffness measures at the maximal tolerable load was excellent ranging from 0.95-1.00 and good to excellent ranging from 0.82-0.93, respectively. Trial averaging was found to reduce standard error of measurement by a mean of 35.2% over all measurement conditions compared to a single trial. Bland and Altman plots for agreement in lumbar spine stiffness measurements varied from - 0.3 +/- 1.2 at unloaded condition to - 0.2 +/- 1.2 at loaded condition. Data from two participants were removed due to the development of back pain between two sessions. CONCLUSION: This study introduced a new technique for measuring spinal stiffness over an entire spinal region in asymptomatic human participants. The new technique produced reliable measurements quantifying the load-displacement values for within-session and between-session assessments.

Patients with adolescent idiopathic scoliosis perceive positive improvements regardless of change in the Cobb angle - Results from a randomized controlled trial comparing a 6-month Schroth intervention added to standard care and standard care alone. SOSORT 2018 Award winner.

BACKGROUND: The Cobb angle is proposed as the "disease process" outcome for scoliosis research because therapies aim to correct or stop curve progression. While the Scoliosis Research Society recommends the Cobb angle as the primary outcome, the Society on Scoliosis Orthopaedic and Rehabilitation Treatment prioritises, as a general goal, patient related outcomes over Cobb angle progression. OBJECTIVE: To determine the threshold of change in the Cobb angle in adolescents with idiopathic scoliosis (AIS) who perceive improvement in a 6-months randomized controlled trial comparing a Schroth exercise intervention added to the standard of care to the standard of care alone. METHODS: This is a secondary analysis of data from a randomized controlled trial of 50 patients with AIS, with curves ranging from 10° to 45°, with or without a brace. Participants with diagnoses other than AIS, surgical candidates or patients who had scoliosis surgery were excluded. The 6-month interventions consisted of Schroth exercises added to standard-of-care (observation or bracing) with daily home exercises and weekly therapy sessions (Schroth) or standard-of-care alone (Control). The anchor method for estimating the minimal important difference (MID) in the largest Cobb angles (LC) was used. Patient-reported change in back status over the 6-month treatment period was measured using the Global Rating of Change (GRC) scale as anchor varying from - 7 ("great deal worse") to + 7 ("great deal better"). Participants were divided into two groups based on GRC scores: Improved (GRC ≥2) or Stable/Not Improved (GRC ≤1). MID was defined as the change in the LC that most accurately predicted the GRC classification as per the receiver operating characteristic curve (ROC). RESULTS: The average age was 13.4 ± 1.6 years and the average LC was 28.5 ± 8.8 °s. The average GRC in the control group was - 0.1 ± 1.6, compared to + 4.4 ± 2.2 in the Schroth group. The correlation between LC and GRC was adequate (r = - 0.34, p < 0.05). The MID for the LC was 1.0 °. The area under the ROC was 0.69 (0.52-0.86), suggesting a 70% chance to properly classify a patient as perceiving No Improvement/Stable or Improvement based on the change in the LC. CONCLUSION: Patients undergoing Schroth treatment perceived improved status of their backs even if the Cobb angle did not improve beyond the conventionally accepted threshold of 5°. Standard of care aims to slow/stop progression while Schroth exercises aim to improve postural balance, signs and symptoms of scoliosis. Given the very small MID, perceived improvement in back status is likely due to something other than the Cobb angle. This study warrants investigating alternatives to the Cobb angle that might be more relevant to patients. TRIAL REGISTRATION: ClinicalTrials.gov , NCT01610908 . Retrospectively registered on April 2, 2012 (first posted on June 4, 2012 - https://clinicaltrials.gov/ct2/keydates/NCT01610908 ).

3D Markerless asymmetry analysis in the management of adolescent idiopathic scoliosis.

BACKGROUND: Three dimensional (3D) markerless asymmetry analysis was developed to assess and monitor the scoliotic curve. While the developed surface topography (ST) indices demonstrated a strong correlation with the Cobb angle and its change over time, it was reported that the method requires an expert for monitoring the procedure to prevent misclassification for some patients. Therefore, this study aimed at improving the user-independence level of the previously developed 3D markerless asymmetry analysis implementing a new asymmetry threshold without compromising its accuracy in identifying the progressive scoliotic curves. METHODS: A retrospective study was conducted on 128 patients with Adolescent Idiopathic Scoliosis (AIS), with baseline and follow-up radiograph and surface topography assessments. The suggested "cut point" which was used to separate the deformed surfaces of the torso from the undeformed regions, automatically generated deviation patches corresponding to scoliotic curves for all analyzed surface topography scans. RESULTS: By changing the "cut point" in the asymmetry analysis for monitoring scoliotic curves progression, the sensitivity for identifying curve progression was increased from 68 to 75%, while the specificity was decreased from 74 to 59%, compared with the original method with different "cut point". CONCLUSIONS: These results lead to a more conservative approach in monitoring of scoliotic curves in clinical applications; smaller number of radiographs would be saved, however the risk of having non-measured curves with progression would be decreased.

A chicken intestinal ligated loop model to study the virulence of Clostridium perfringens isolates recovered from antibiotic-free chicken flocks.

Necrotic enteritis (NE) is a major problem in antibiotic-free (ABF) chicken flocks and specific strains of Clostridium perfringens are known to induce NE. The objective of this study was to develop a chicken intestinal ligated loop model in order to compare the virulence of various C. perfringens strains recovered from consecutive ABF flocks with and without NE. Intestinal loops were surgically prepared in 10 anaesthetized specific-pathogen-free chickens and alternately inoculated with C. perfringens isolates or brain heart infusion (BHI) media. Histological lesion scoring was performed for each loop. All strains from NE-affected flocks induced histological lesions compatible with NE whereas inoculation of loops with a commensal C. perfringens strain or BHI did not. Among inoculated strains, CP0994 (netB-positive and cpb2-positive) and CP-2003-1256 (netB-positive) demonstrated mean histological lesion scores significantly higher (P < 0.01) than those obtained with a commensal strain or BHI whereas strain CP1073 (netB-negative and cpb2-positive) induced intestinal lesions without significantly higher scores. In loops where villi were colonized by Gram-positive rods, significantly higher (P < 0.01) mean histological lesion scores were observed. This result supports the hypothesis that colonization of the intestinal mucosa by C. perfringens is a critical step in the pathogenesis of NE. Finally, we demonstrated the importance of controlling virulent C. perfringens strains in ABF chicken flocks as a highly virulent strain can be present in consecutive flocks with NE and possibly affect multiple flocks.

Deep soil carbon dynamics are driven more by soil type than by climate: a worldwide meta-analysis of radiocarbon profiles.

The response of soil carbon dynamics to climate and land-use change will affect both the future climate and the quality of ecosystems. Deep soil carbon (>20 cm) is the primary component of the soil carbon pool, but the dynamics of deep soil carbon remain poorly understood. Therefore, radiocarbon activity (Δ14C), which is a function of the age of carbon, may help to understand the rates of soil carbon biodegradation and stabilization. We analyzed the published 14C contents in 122 profiles of mineral soil that were well distributed in most of the large world biomes, except for the boreal zone. With a multivariate extension of a linear mixed-effects model whose inference was based on the parallel combination of two algorithms, the expectation-maximization (EM) and the Metropolis-Hasting algorithms, we expressed soil Δ14C profiles as a four-parameter function of depth. The four-parameter model produced insightful predictions of soil Δ14C as dependent on depth, soil type, climate, vegetation, land-use and date of sampling (R2=0.68). Further analysis with the model showed that the age of topsoil carbon was primarily affected by climate and cultivation. By contrast, the age of deep soil carbon was affected more by soil taxa than by climate and thus illustrated the strong dependence of soil carbon dynamics on other pedologic traits such as clay content and mineralogy.

Towards using a full spectrum of early clinical trial data: a retrospective analysis to compare potential longitudinal categorical models for molecular targeted therapies in oncology.

Following the pattern of phase I clinical trials for cytotoxic drugs, dose-finding clinical trials in oncology of molecularly targeted agents (MTA) aim at determining the maximum tolerated dose (MTD). In classical phase I clinical trials, MTD is generally defined by the number of patients with short-term major treatment toxicities (usually called dose-limiting toxicities, DLT), occurring during the first cycle of study treatment (e.g. within the first 3weeks of treatment). However, S. Postel-Vinay (2011) highlighted that half of grade 3 to 4 toxicities, usually considered as DLT, occur after the first cycle of MTA treatment. In addition, MTAs could induce other moderate (e.g. grade 2) toxicities which could be taken into account depending on their clinical importance, chronic nature and duration. Ignoring these late toxicities may lead to an underestimation of the drug toxicity and to wrong dose recommendations for phase II and III clinical trials. Some methods have been proposed, such as the time-to-event continuous reassessment method (Cheung 2000 and Mauguen 2011), to take into account the late toxicities. We suggest approaches based on longitudinal models (Doussau 2013). We compare several models for longitudinal data, such as transitional or marginal models, to take into account all relevant toxicities occurring during the entire length of the patient treatment (and not just the events within a predefined short-term time-window). These models allow the statistician to benefit from a larger amount of safety data which could potentially improve that accuracy in MTD assessment.

Correlation between Cobb angle, spinous process angle (SPA) and apical vertebrae rotation (AVR) on posteroanterior radiographs in adolescent idiopathic scoliosis (AIS).

PURPOSE: To investigate the accuracy and reliability of the Cobb angle, the spinous process angle (SPA), and apical vertebral rotation (AVR) for measuring adolescent idiopathic scoliosis (AIS), and to evaluate the correlations between these measurements. METHODS: A retrospective study of two sets of standing posteroanterior radiographs of patients with AIS was performed. The first set was 59 consecutive patients with AIS with Cobb angles <45° and the second set was 25 patients with Cobb angles >45°. The Cobb angle, SPA and AVR of each curve was measured twice by three observers with varying measurement experience. The mean absolute difference, standard deviation, and intra- and inter-rater reliability coefficients for each measurement were examined. The Pearson correlation coefficients between any two parameters were reported. The association of the Cobb angle with the SPA and AVR was examined using a multiple regression model. RESULTS: The average intra- and inter-observer reliabilities (ICC [2, 1]) of the Cobb angle, SPA, and AVR were 0.99, 0.95, 0.92 and 0.98, 0.88, 0.83, respectively. The correlation coefficients (r) between Cobb angle and SPA, Cobb angle and AVR, and SPA and AVR were 0.93, 0.68, and 0.60, respectively. Using multiple regression, the association between the Cobb angle and SPA combined with AVR was R (2) = 0.90. The resulting regression model was: [Formula: see text]. CONCLUSION: The SPA has high correlation with the Cobb angle. Including the AVR as an additional factor in multiple regression improves the prediction of the Cobb angle.