Estimation of footprints of the canine stifle ligaments using deformable shape templates of bones.

Knowledge regarding the ligament footprints in the canine stifle is essential for biomechanical modeling of the joint and patient-specific surgical planning for anatomical ligament reconstruction. The present study aimed to establish and evaluate deformable shape templates (DSTs) of the femur and tibia with footprints of the cruciate and collateral ligaments embedded for the noninvasive estimation of ligament footprint positions. To this end, a data set of computed tomography (CT)-derived surface models of the femur and tibia were established and used to build statistical shape models (SSMs). The contours of the stifle ligaments were obtained from CT scans of 27 hindlimb specimens with radio-opaque markings on the ligament footprints. The DST, constructed by embedding averaged footprint contours into the SSM, was used to estimate subject-specific ligament footprints in a leave-one-out cross-validation framework. The DST predictions were compared with those derived from radio-opaque-marked footprints. The results showed that the averaged Euclidean distances between the estimated and reference footprint centroids were less than 1.2 mm for the cruciate ligaments and 2.0 mm for the collateral ligaments. The DST appeared to provide a feasible alternative approach for noninvasively estimating the footprints of the stifle ligaments in vivo.

Ex vivo biomechanical evaluation of extracapsular stabilization with quasi-isometric points in canine cranial cruciate ligament-deficient stifles.

BACKGROUND: Cranial cruciate ligament (CCL) disease is one of the most common causes of lameness in dogs. The extracapsular stabilization (ECS) utilizing bone anchors and monofilament nylon leader was an alternative treatment for CCL-deficient (CCLD) dogs. However, the biomechanical response of the canine stifle to such a surgical repair strategy in conjunction with the use of recently reported quasi-isometric anchoring points remains unclear. The objectives of the study were to evaluate the mobility and stability of CCL-intact, CCLD, and CCLD stifles repaired with ECS at two different pairs of quasi-isometric points (quasi-IPs). METHODS: Twelve stifle specimens from 7 dogs underwent mobility and stability tests under 4 different conditions, namely, CCL-intact, CCLD, and ECS-repaired at 2 different pairs of quasi-IPs (referred to as ECS-IP1 and ECS-IP2). The mobility tests evaluated 6 degrees-of-freedom stifle kinematics during flexion and extension. The stability tests involved cranial drawer and tibial internal rotation (IR) tests at various stifle opening angles and quantifying the cranial tibial translation (CTT) and tibial IR angles under constantly applied loadings. RESULTS: The ECS repaired at quasi-IPs was shown to restore cranial instability of the stifles with averaged CTT magnitudes < 1.4 mm. During the tibial IR test, the ECS treatments resulted in significantly less tibial IR compared to those in intact CCL stifles. The mobility tests showed similar results. CONCLUSION: The 2 chosen pairs of quasi-IPs were shown to effectively correct the excessive CTT caused by CCLD stifles, whereas the excessive tibial external rotation in comparison to those of intact stifles should be considered for its subsequent influence on joint alignment and the contact pressure applied to the stifle joint.

Integration of statistical shape modeling and alternating interpolation-based model tracking technique for measuring knee kinematics in vivo using clinical interleaved bi-plane fluoroscopy.

Background: A 2D fluoroscopy/3D model-based registration with statistical shape modeling (SSM)-reconstructed subject-specific bone models will help reduce radiation exposure for 3D kinematic measurements of the knee using clinical alternating bi-plane fluoroscopy systems. The current study aimed to develop such an approach and evaluate in vivo its accuracy and identify the effects of the accuracy of SSM models on the kinematic measurements. Methods: An alternating interpolation-based model tracking (AIMT) approach with SSM-reconstructed subject-specific bone models was used for measuring 3D knee kinematics from dynamic alternating bi-plane fluoroscopy images. A two-phase optimization scheme was used to reconstruct subject-specific knee models from a CT-based SSM database of 60 knees using one, two, or three pairs of fluoroscopy images. Using the CT-reconstructed model as a benchmark, the performance of the AIMT with SSM-reconstructed models in measuring bone and joint kinematics during dynamic activity was evaluated in terms of mean target registration errors (mmTRE) for registered bone poses and the mean absolute differences (MAD) for each motion component of the joint poses. Results: The mmTRE of the femur and tibia for one image pair were significantly greater than those for two and three image pairs without significant differences between two and three image pairs. The MAD was 1.16 to 1.22° for rotations and 1.18 to 1.22 mm for translations using one image pair. The corresponding values for two and three image pairs were 0.75 to 0.89° and 0.75 to 0.79 mm; and 0.57 to 0.79° and 0.6 to 0.69 mm, respectively. The MAD values for one image pair were significantly greater than those for two and three image pairs without significant differences between two and three image pairs. Conclusions: An AIMT approach with SSM-reconstructed models was developed, enabling the registration of interleaved fluoroscopy images and SSM-reconstructed models from more than one asynchronous fluoroscopy image pair. This new approach had sub-millimeter and sub-degree measurement accuracy when using more than one image pair, comparable to the accuracy of CT-based methods. This approach will be helpful for future kinematic measurements of the knee with reduced radiation exposure using 3D fluoroscopy with clinically alternating bi-plane fluoroscopy systems.

Effects of lateral instability on ankle coupled motions in vivo using 3D fluoroscopy.

Lateral ankle instability (LAI) compromises the normal kinematics of the ankle, affecting activities of daily living. In vitro kinematics of ankles with LAI during single-plane motions are available, but the active control stability of these motions remains unclear. The current study measured the 3D ankle kinematics during unresisted single-plane motion tests using a bi-plane fluoroscope with a CT model-based 2D/3D registration method in 12 patients with LAI and 14 healthy peers. The coupling of the kinematic components at the talocrural and subtalar joints was quantified by the path difference between the forward and return paths of the coupled motion. Significantly increased path differences were found in the subtalar dorsiflexion/plantarflexion and inversion/eversion components during internal/external rotation tests (p < 0.05). During inversion/eversion, significantly reduced tibiocalcaneal ranges of motion and the path differences in the talocrural and subtalar dorsiflexion/plantarflexion components were noted (p < 0.05). The current results suggest that chronic LAI had compromised control stability at the subtalar joint during internal/external rotation tests and a conservative motion control strategy with significantly reduced ranges of motion to maintain good control of out-of-plane motion components in response to direct challenges of the anterior talofibular ligament during inversion/eversion tests. The current results also suggest that, compared to kinematic patterns of individual components, the path difference of the coupled motion may serve as a better measure of the motion control stability of the ankle in differentiating LAI from healthy controls.

In vivo three-dimensional isometry analysis of suture attachment sites for extracapsular suture stabilization of the canine stifle.

BACKGROUND: The study aimed to perform isometry analysis of a selection of suture attachment points for extracapsular stabilization with three-dimensional (3D) measurements and normal gait kinematics of the stifle joint. METHODS: Thirteen client-owned dogs were recruited. Fluoroscopic images of the stifle during treadmill walking and computed tomography of the same joint were acquired. Stifle kinematics were reconstructed using 3D model-based fluoroscopic analysis. Variability of the distance between the femoral and tibial attachment sites across gait cycles was evaluated. The maximum length variation (MLV) and maximum length percent variation (MLPV) were quantified and used to determine the level of isometry of the attachment site combinations. RESULTS: A selection of combinations with lower mean MLV (<2.5 mm) or MLPV (<8%) was identified from 315 combinations, and all the combinations involved femoral attachment sites near the distal pole of the lateral fabella. The combinations also involving tibial attachment sites near the proximal tibial crest showed improved isometry, with an MLPV < 6%. CONCLUSION: Combinations using attachment sites around the distal pole of the lateral fabella and proximal tibial crest or caudal to the long digit extensor groove appeared to have improved isometry.

Three-Dimensional Subject-Specific Knee Shape Reconstruction with Asynchronous Fluoroscopy Images Using Statistical Shape Modeling.

Background and objectives: Statistical shape modeling (SSM) based on computerized tomography (CT) datasets has enabled reasonably accurate reconstructions of subject-specific 3D bone morphology from one or two synchronous radiographs for clinical applications. Increasing the number of radiographic images may increase the reconstruction accuracy, but errors related to the temporal and spatial asynchronization of clinical alternating bi-plane fluoroscopy may also increase. The current study aimed to develop a new approach for subject-specific 3D knee shape reconstruction from multiple asynchronous fluoroscopy images from 2, 4, and 6 X-ray detector views using a CT-based SSM model; and to determine the optimum number of planar images for best accuracy via computer simulations and in vivo experiments. Methods: A CT-based SSM model of the knee was established from 60 training models in a healthy young Chinese male population. A new two-phase optimization approach for 3D subject-specific model reconstruction from multiple asynchronous clinical fluoroscopy images using the SSM was developed, and its performance was evaluated via computer simulation and in vivo experiments using one, two and three image pairs from an alternating bi-plane fluoroscope. Results: The computer simulation showed that subject-specific 3D shape reconstruction using three image pairs had the best accuracy with RMSE of 0.52 ± 0.09 and 0.63 ± 0.085 mm for the femur and tibia, respectively. The corresponding values for the in vivo study were 0.64 ± 0.084 and 0.69 ± 0.069 mm, respectively, which was significantly better than those using one image pair (0.81 ± 0.126 and 0.83 ± 0.108 mm). No significant differences existed between using two and three image pairs. Conclusion: A new two-phase optimization approach was developed for SSM-based 3D subject-specific knee model reconstructions using more than one asynchronous fluoroscopy image pair from widely available alternating bi-plane fluoroscopy systems in clinical settings. A CT-based SSM model of the knee was also developed for a healthy young Chinese male population. The new approach was found to have high mode reconstruction accuracy, and those for both two and three image pairs were much better than for a single image pair. Thus, two image pairs may be used when considering computational costs and radiation dosage. The new approach will be useful for generating patient-specific knee models for clinical applications using multiple asynchronous images from alternating bi-plane fluoroscopy widely available in clinical settings. The current SSM model will serve as a basis for further inclusion of training models with a wider range of sizes and morphological features for broader applications.

Ultrasonographic appearance of pseudo-placentational endometrial hyperplasia in a dog.

A 5-year-old, clinically normal intact female Miniature Schnauzer was presented for demonstrative ultrasonography in a seminar. She had two pregnancies in the past and had a natural mating 2 months previously. Ultrasonography revealed a segmental and circumferential mural thickening of the right uterine horn. The endometrium was markedly thickened with multiple organized hyperechoic linear striations, perpendicular to the mucosal surface. Histology revealed focal endometrial hyperplasia resembling the maternal tissue of the normal canine placenta. A diagnosis of spontaneous pseudo-placentational endometrial hyperplasia (PEH) was made. This study described a unique ultrasonographic appearance of PEH, which may facilitate the diagnosis of PEH.

In vivo three-dimensional mandibular kinematics and functional point trajectories during temporomandibular activities using 3d fluoroscopy.

OBJECTIVES: To measure in vivo three-dimensional kinematics of the mandible and associated end-point trajectories and to quantify their relationships during temporomandibular joint activities using 3D fluoroscopy. METHODS: A novel fluoroscopy-based 3D measurement method was used to measure motions of the mandible and the associated end points (i.e. incisors and lateral poles of both condyles) during open close, lateral gliding and protrusion-retraction movements in healthy young individuals. The contributions of each of the rotational and translational components of the mandible to the end-point trajectories were quantified through experiment-based computer simulations. RESULTS: The mandibular rotation was found to account for 91% of the maximal mouth-opening-capacity and 73% of the maximal lateral incisor movement, while the condylar translation contributed to 99% of the anterior protrusion distance. Incisor trajectories were nearly vertical within the first 60% of the maximal opening during the open-close movement. CONCLUSIONS: Similar condylar downward rotation paths but with bilaterally asymmetrical ranges were used to perform basic mandibular movements of different targeted TI trajectories in three dimensions, that is, open-close, lateral-gliding and protrusion-retraction. Mandibular rotations contributed to the majority of the principal displacement components of the incisor, that is, vertical during open-close and towards the working-side-during lateral-gliding, while mandibular translation contributed mainly to the forward movement of the incisor during protrusion-retraction. Owing to the anatomical constraints, the freedom of mandibular translation is limited and mainly in the anteroposterior direction, which is considered helpful for the control and stability of the TMJ during oral activities.

Description of soft tissue artifacts and related consequences on hindlimb kinematics during canine gait.

BACKGROUND: Soft tissue artifacts (STAs) are a source of error in marker-based gait analysis in dogs. While some studies have revealed the existence of STAs in the canine hindlimb, STAs and their influence on kinematic gait analysis remain unclear. METHODS: Thirteen healthy Taiwan dogs affixed with twenty skin markers on the thigh and crus were recruited. Soft tissue artifacts and their influence on the determination of segment poses and stifle angles were assessed by simultaneously measuring marker trajectories and kinematics of the underlying bones via a model-based fluoroscopic analysis method. RESULTS: Markers on the thigh showed higher STAs than those on the crus, with root-mean-square amplitudes up to 15.5 mm. None of the tested marker clusters were able to accurately reproduce the skeletal poses, in which the maximum root-mean-square deviations ranged from 3.4° to 8.1°. The use of markers resulted in overestimated stifle flexion during 40-60% of the gait cycle and underestimated stifle flexion during 80-90% of the gait cycle. CONCLUSIONS: Considerable magnitudes and effects of STAs on the marker-based 3D gait analysis of dogs were demonstrated. The results indicate that the development of error-compensation techniques based on knowledge regarding STAs is warranted for more accurate gait analysis.

Evaluation of a multibody kinematics optimization method for three-dimensional canine pelvic limb gait analysis.

BACKGROUND: Skin marker-based three-dimensional kinematic gait analysis were commonly used to assess the functional performance and movement biomechanics of the pelvic limb in dogs. Unfortunately, soft tissue artefact would compromise the accuracy of the reproduced pelvic limb kinematics. Multibody kinematics optimization framework was often employed to compensate the soft tissue artefact for a more accurate description of human joint kinematics, but its performance on the determination of canine pelvic limb skeletal kinematics has never been evaluated. This study aimed to evaluate a multibody kinematics optimization framework used for the determination of canine pelvic limb kinematics during gait by comparing its results to those obtained using computed tomography model-based fluoroscopy analysis. RESULTS: Eight clinically normal dogs were enrolled in the study. Fluoroscopy videos of the stifle joint and skin marker trajectories were acquired when the dogs walked on a treadmill. The pelvic limb kinematics were reconstructed through marker-based multibody kinematics optimization and single-body optimization. The reference kinematics data were derived via a model-based fluoroscopy analysis. The use of multibody kinematics optimization yielded a significantly more accurate estimation of flexion/extension of the hip and stifle joints than the use of single-body optimization. The accuracy of the joint model parameters and the weightings to individual markers both influenced the soft tissue artefact compensation capability. CONCLUSIONS: Multibody kinematics optimization designated for soft tissue artefact compensation was established and evaluated for its performance on canine gait analysis, which provided a further step in more accurately describing sagittal plane kinematics of the hip and stifle joints.

Effects of soft tissue artefacts on computed segmental and stifle kinematics in canine motion analysis.

Skin marker-based motion analysis has been widely used to evaluate the functional performance of canine gait and posture. However, the interference of soft tissues between markers and the underlying bones (soft tissue artefacts, STAs) may lead to errors in kinematics measurements. Currently, no optimal marker attachment sites and cluster compositions are recommended for canine gait analysis. The current study aims to evaluate cluster-level STAs and the effects of cluster compositions on the computed stifle kinematics. Ten mixed-breed healthy dogs affixed with 19 retroreflective markers on the thigh and shank were enrolled. During isolated stifle passive extension, the marker trajectories were acquired with a motion capture system, and the skeletal poses were determined by integrating fluoroscopic and CT images of the bones. The cluster-level STAs were assessed, and clusters were paired to calculate the stifle kinematics. A selection of cluster compositions was useful for deriving accurate sagittal and frontal plane stifle kinematics with flexion angles below 50 per cent of the range of motion. The findings contribute to improved knowledge of canine STAs and their influence on motion measurements. The marker composition with the smallest error in describing joint kinematics is recommended for future applications and study in dogs during dynamic gait assessment.

Patient-specific instrumentation improves functional kinematics of minimally-invasive total knee replacements as revealed by computerized 3D fluoroscopy.

BACKGROUND AND OBJECTIVES: Minimally-invasive total knee arthroplasty (MIS-TKA) has demonstrated very good short-term success, but its mid- to long-term results remain inconclusive. The success may be related to the tradeoff between a small incision and accurate positioning of the implant components. Patient-specific instrumentation (PSI) aims to improve the accuracy in restoring the knee axis and the clinical outcomes for MIS-TKA, but the results are yet to be confirmed by accurate assessment during functional activities. The purpose of the current study was to measure and compare the in vivo three-dimensional (3D) rigid-body and surface kinematics of MIS-TKA implanted with and without PSI during isolated knee active flexion/extension and sit-to-stand using state-of-the-art 3D model-based fluoroscopy technology. METHODS: Ten patients treated for advanced medial knee osteoarthritis by MIS-TKA without PSI (non-PSI group) and nine with PSI (PSI group) participated in the current study. Each subject performed non-weight-bearing knee flexion/extension and sit-to-stand tasks while the motion of the prosthetic knee was under bi-plane fluoroscopy surveillance. The computer models of each of the knee prosthesis components were registered to the measured fluoroscopy images for each time frame via a novel validated 3D fluoroscopy method. Non-parametric 1-tailed Mann-Whitney tests were performed to detect the differences in the joint and surface kinematic variables every 10° of knee flexion between the non-PSI and PSI groups. The 1-tailed significance level was at α = 0.05. RESULTS: The PSI group showed clear, coupled flexion/internal rotation during activities, while the non-PSI group remained roughly at an externally rotated position with slight internal rotations. The coupled rotation in the PSI group was accompanied by an anterior displacement of the medial contact and a posterior displacement of the lateral contact, which was different from the screw-home mechanism. Neither of the two groups showed the normal roll-back phenomenon, i.e., posterior translation of the femur relative to the tibia during knee flexion. CONCLUSIONS: With the state-of-the-art 3D fluoroscopy method, differences in both the rigid-body and surface kinematics of the prosthetic knees between MIS-TKA with and without PSI were identified. Patients with PSI demonstrated significant positive effects on the reconstructed rigid-body kinematics of the knee, showing clearer coupled flexion/internal rotations - an important kinematic characteristic in healthy knees - than those without PSI during activities with or without weight-bearing. However, none of them showed normal contact patterns. The current findings will be helpful for surgical instrument design, as well as for surgical decision-making in MIS total knee arthroplasty.

Measuring three-dimensional tibiofemoral kinematics using dual-slice real-time magnetic resonance imaging.

PURPOSE: The purpose of this study is to propose and evaluate a slice-to-volume registration (SVR) method integrating an advanced dual-slice real-time magnetic resonance image (MRI) and three-dimensional (3D) MRI volume of the tibiofemoral joint for determining their 3D kinematics. METHODS: The real-time and 3D MRI of the knee were collected from 12 healthy adults at 5 static flexion positions and during dynamic flexion/extension movement. The 3D positions and orientations of the femur and tibia were obtained by registering their volumetric models constructed from the 3D MRI to dual-slice real-time MRI using an optimization process. The proposed method was quantitatively evaluated for its performance in terms of the robustness and measurement accuracy, and compared to those of a single-slice SVR method. Its repeatability in measuring knee kinematics during flexion/extension movement was also determined. RESULTS: In comparison to the single-slice SVR method, the dual-slice method was significantly superior, giving a successful registration rate > 95%, a bias less than 0.5 mm in translations and 0.6° in rotations and a precision <0.7 mm in translations and 0.9° in rotations for determining the 3D tibiofemoral poses. For repeatability of the dual-slice SVR in measuring tibiofemoral kinematics during dynamic flexion/extension, the means of the time-averaged standard deviations were <0.9° for joint angles and 0.5 mm for joint translations. CONCLUSION: A dual-slice SVR method in conjunction with real-time MRI has been developed and evaluated for its performance in measuring 3D kinematics of the tibiofemoral joint in 12 young adults in terms of the accuracy, robustness, and repeatability. The proposed MRI-based 3D measurement method provides a noninvasive and ionizing radiation-free approach for 3D kinematic measurement of the tibiofemoral joint, which will be helpful for future academic and clinical applications.

Quantification of three-dimensional soft tissue artifacts in the canine hindlimb during passive stifle motion.

BACKGROUND: Three-dimensional joint kinematics during canine locomotion are commonly measured using skin marker-based stereophotogrammetry technologies. However, marker-related errors caused by the displacement of the skin surface relative to the underlying bones (i.e., soft tissue artifacts, STA) may affect the accuracy of the measurements and obscure clinically relevant information. Few studies have assessed STA in canine limbs during kinematic analysis. The magnitudes and patterns of the STA and their influence on kinematic analysis remain unclear. Therefore, the current study aims to quantify the in vivo STA of skin markers on the canine thigh and crus during passive joint motion. The stifle joints of ten dogs were passively extended while the skin markers were measured using a motion capture system, and skeletal kinematics were determined using a CT-to-fluoroscopic image registration method. RESULTS: The skin markers exhibited considerable STA relative to the underlying bones, with a peak amplitude of 27.4 mm for thigh markers and 28.7 mm for crus markers; however, the amplitudes and displacement directions at different attachment sites were inconsistent. The markers on the cranial thigh and lateral crus closer to the stifle joint had greater STA amplitudes in comparison to those of other markers. Most markers had STA with linear and quadratic patterns against the stifle flexion angles. These STA resulted in underestimated flexion angles but overestimated adduction and internal rotation when the stifle was flexed to greater than 90°. CONCLUSIONS: Marker displacements relative to the underlying bones were prominent in the cranial aspect of the thigh and the proximal-lateral aspect of the crus. The calculated stifle kinematic variables were also affected by the STA. These findings can provide a reference for marker selection in canine motion analysis for similar motion tasks and clarify the relationship between STA patterns and stifle kinematics; the results may therefore contribute to the development of STA models and compensation techniques for canine motion analysis.

A model-based tracking method for measuring 3D dynamic joint motion using an alternating biplane x-ray imaging system.

PURPOSES: To propose a new model-based tracking method for measuring three-dimensional (3D) dynamic joint kinematics using a clinical alternating biplane x-ray imaging system; and to quantify in vitro its errors in measuring ankle and knee motions at different motion speeds. METHODS: A new model-based tracking method based on motion component partition and interpolation (MCPI) was developed for measuring 3D dynamic joint kinematics based on a clinical alternating biplane x-ray imaging system. Two detectors of the biplane imaging system placed perpendicular to each other were operated to collect alternating fluoroscopic images of the targeted joint during tasks. The CT data of the joint were also acquired for the reconstruction of volumetric and surface models of each of the associated bones. The CT-based models of the bones were first registered to the alternating images using a model-to-single-plane fluoroscopic image registration method, and the resulting bone poses were then refined using a two-level optimization with motion component partition and model vertex trajectory interpolation. The MCPI method was evaluated in vitro for measurement errors for an ankle and a knee specimen moving at different speeds against a standard reference provided by a highly accurate motion capture system. The positional and rotational errors of the measured bone poses were quantified in terms of the bias, precision, and root-mean-squared errors (RMSE), as well as the mean target registration error (mTRE), a final mTRE less than 2.5 mm indicating a successful registration. RESULTS: The new method was found to have RMSE of bone pose measurements of less than 0.18 mm for translations and 0.72° for rotations for the ankle, and 0.33 mm and 0.74° for the knee with a high successful registration rate (>97%), and did not appear to be affected by joint motion speeds. Given the same alternating fluoroscopic images, the MCPI method outperformed the typical biplane analysis method assuming zero time offset between the two fluoroscopic views. The differences in performance between the methods were increased with increased joint motion speed. With the accurate bone pose data, the new method enabled talocrural, subtalar, and tibiofemoral kinematics measurements with submillimeter and subdegree accuracy, except for an RMSE of 1.04° for the internal/external rotation of the talocrural joint. CONCLUSIONS: A new model-based tracking method based on MCPI has been developed for measuring dynamic joint motions using an alternating biplane x-ray imaging system widely available in medical centers. The MCPI method has been demonstrated in vitro to be highly accurate in determining the 3D kinematics of the bones of both the ankle joint complex and the knee. The current results suggest that the MCPI method would be an effective approach for measuring in vivo 3D kinematics of dynamic joint motion in a clinical setting equipped with an alternating biplane x-ray imaging system.

Chicken interleukin-1ß mutants are effective single-dose vaccine adjuvants that enhance mucosal immune response.

The use of cytokines as adjuvants in poultry is promising because they may enhance immune responses to antigens. In this study, we created two mutants, chicken interleukin-1 beta (ChIL-1ß) Q19A and R140A, which exhibited significantly increased in vivo biological activity compared with wild-type ChIL-1ß. The potential mucosal adjuvant activity of the mutants Q19A and R140A was evaluated in chickens through the intranasal coadministration of a single dose of the Newcastle disease virus (NDV) vaccine with Q19A or R140A. Compared with chickens vaccinated with only the NDV vaccine or the NDV vaccine plus wild-type recombinant ChIL-1ß, chickens vaccinated with Q19A or R140A had significantly increased serum hemagglutination-inhibition antibody titers and anti-NDV-specific IgA antibody levels 1 week later, a high amount of interferon-γ secretion from splenocytes, and increased secretory IgA accumulated in nasal tissues. In addition, molecular dynamics simulations of the mutant R140A bound to its receptor (IL-1RI) and receptor accessory protein (IL-1RAcP) were more energetically favorable than the analogous wild-type ternary complex resulting in a decreased energy, which may stabilize the R140A/IL-1RI/IL-1RAcP complex. In conclusion, the mutants Q19A and R140A are effective adjuvants that accelerate and enhance chicken mucosal immunity when co-administered with one dose of the NDV vaccine.

Soft tissue artefacts of skin markers on the lower limb during cycling: Effects of joint angles and pedal resistance.

Soft tissue artefacts (STA) are a major error source in skin marker-based measurement of human movement, and are difficult to eliminate non-invasively. The current study quantified in vivo the STA of skin markers on the thigh and shank during cycling, and studied the effects of knee angles and pedal resistance by using integrated 3D fluoroscopy and stereophotogrammetry. Fifteen young healthy adults performed stationary cycling with and without pedal resistance, while the marker data were measured using a motion capture system, and the motions of the femur and tibia/fibula were recorded using a bi-plane fluoroscopy-to-CT registration method. The STAs with respect to crank and knee angles over the pedaling cycle, as well as the within-cycle variations, were obtained and compared between resistance conditions. The thigh markers showed greater STA than the shank ones, the latter varying linearly with adjacent joint angles, the former non-linearly with greater within-cycle variability. Both STA magnitudes and within-cycle variability were significantly affected by pedal resistance (p<0.05). The STAs appeared to be composed of one component providing the stable and consistent STA patterns and another causing their variations. Mid-segment markers experienced smaller STA ranges than those closer to a joint, but tended to have greater variations primarily associated with pedal resistance and muscle contractions. The current data will be helpful for a better choice of marker positions for data collection, and for developing methods to compensate for both stable and variation components of the STA.

Standardization proposal of soft tissue artefact description for data sharing in human motion measurements.

Soft tissue artefact (STA) represents one of the main obstacles for obtaining accurate and reliable skeletal kinematics from motion capture. Many studies have addressed this issue, yet there is no consensus on the best available bone pose estimator and the expected errors associated with relevant results. Furthermore, results obtained by different authors are difficult to compare due to the high variability and specificity of the phenomenon and the different metrics used to represent these data. Therefore, the aim of this study was twofold: firstly, to propose standards for description of STA; and secondly, to provide illustrative STA data samples for body segments in the upper and lower extremities and for a range of motor tasks specifically, level walking, stair ascent, sit-to-stand, hip- and knee-joint functional movements, cutting motion, running, hopping, arm elevation and functional upper-limb movements. The STA dataset includes motion of the skin markers measured in vivo and ex vivo using stereophotogrammetry as well as motion of the underlying bones measured using invasive or bio-imaging techniques (i.e., X-ray fluoroscopy or MRI). The data are accompanied by a detailed description of the methods used for their acquisition, with information given about their quality as well as characterization of the STA using the proposed standards. The availability of open-access and standard-format STA data will be useful for the evaluation and development of bone pose estimators thus contributing to the advancement of three-dimensional human movement analysis and its translation into the clinical practice and other applications.

Effects of soft tissue artifacts on differentiating kinematic differences between natural and replaced knee joints during functional activity.

Functional performance of total knee replacement (TKR) is often assessed using skin marker-based stereophotogrammetry, which can be affected by soft tissue artifacts (STA). The current study aimed to compare the STA and their effects on the kinematics of the knee between twelve patients with TKR and twelve healthy controls during sit-to-stand, and to assess the effects of STA on the statistical between-group comparisons. Each subject performed the sit-to-stand task while motions of the skin markers and the knees were measured by a motion capture system integrated with a three-dimensional fluoroscopy technique. The bone motions measured by the three-dimensional fluoroscopy were taken as the gold standard, with respect to which the STA of the markers were obtained. The STA were found to affect the calculated segmental poses and knee kinematics between the groups differently. The STA resulted in artefactual posterior displacements of the knee joint center, with magnitudes significantly greater in TKR than controls (p<0.01). The STA-induced knee external rotations in TKR were smaller than those in controls with mean differences of 2.3-3.0°. These between-group differences in the STA effects on knee kinematics in turn concealed the true between-group differences in the anterior-posterior translation and internal/external rotation of knee while leading to false significant between-group differences in the abduction/adduction and proximal-distal translation.