Quantifying a novel three-dimensional marker of scoliosis

BACKGROUND

Scoliosis causes abnormal spinal curvature and torsional rotation of the vertebrae and has implications for human suffering and societal cost. In differential geometry, Writhe describes three-dimensional curvature. Differential geometric quantities can inform better diagnostic metrics of scoliotic deformity. This evaluation could help physicians and researchers study scoliosis and determine treatments.

METHODS

Eight adult lumbar spine CT scans were analyzed in custom MATLAB programs to estimate Writhe and Cobb angle. Five patients exhibited scoliotic curvature, and three controls were asymptomatic. Vertebral centroids in three-dimensional space were determined, and Writhe was approximated. A T-test determined whether the affected spines had greater Writhe than the controls. Cohen's D test was used to determine effect size.

RESULTS

Writhe of scoliotic spines (5.4E-4 ± 2.7E-4) was significantly higher than non-scoliotic spines (8.2E-5 ± 1.1E-4; p = 0.008).

CONCLUSION

Writhe, a measure of curvature derived from 3D imaging, is significantly greater in scoliotic than in non-scoliotic spines. Future directions must include more subjects and examine writhe as a marker of scoliosis severity, progression, and response to treatment.

Quantitative imaging of the spine in adolescent idiopathic scoliosis: shifting the paradigm from diagnostic to comprehensive prognostic evaluation

PURPOSE

We aimed to provide a perspective review of the available quantitative imaging modalities of the spine for prognostic evaluation of the adolescent idiopathic scoliosis (AIS).

METHODS

A technical description of the current imaging technologies for quantitative assessment of the pediatric spine with scoliosis was provided, and the pros and cons of each method were discussed. Imaging modalities that quantify the overall 3D alignment of the spine as well as the structural specification of the spinal bone, intervertebral disc, endplates, and ligaments as it pertains to development and progression of the idiopathic spinal deformities in adolescents were discussed.

RESULTS

Low-dose and microdose stereoradiography, ultrasound, and rasterstereography provide quantitative imaging of the 3D spinal alignment with low or no radiation in standing posture which allows repetitive imaging for early detection of the curve development. Quantitative magnetic resonance imaging, including ultrashort dual-echo time and T1-rho can provide quantitative assessment of the spinal tissues relevant to development of idiopathic spinal deformity in pediatric population. New computed tomography scans that uses dual-energy can provides high-resolution measure of the current-state of the bone quality and morphology as well as the osteogenic properties of the bone by quantitative evaluation of the bone marrow.

CONCLUSION

The presented imaging modalities can provide a wide spectrum of quantifiable information relevant to development and progression of the spinal deformity. Clinical application of these technologies can change the paradigm in clinical assessment of the pediatric scoliosis by improving our understanding of the pathogenesis of the idiopathic scoliosis.

Discovering the association between the pre- and post-operative 3D spinal curve patterns in adolescent idiopathic scoliosis

BACKGROUND

The advantage of considering the three-dimensional curve patterns, including the patterns of the vertebral position and alignment, in classification of adolescent idiopathic scoliosis (AIS) patients and whether such classification system relates to the surgical outcomes are not fully determined.

METHODS

A total of 371 AIS patients who received posterior spinal fusion surgery with 2-year follow-up were included retrospectively and consecutively. The 3D positions and orientations of the T1-L5 vertebrae were calculated from the 3D reconstructions of the spines at pre-operative and 2-year follow-up, a total of 102 variables per patient. A probabilistic clustering method was used to cluster the pre-operative and 2-year follow-up 3D spinal curve patterns separately. The distributions of the Lenke types and 3D pre-operative clusters in the post-operative clusters were determined.

RESULTS

A total of nine pre-operative clusters including, four right thoracic types, three left thoracolumbar/lumbar types, one low apex right thoracic/thoracolumbar, and one left thoracic/right lumbar were determined. Three post-operative 3D curve patterns were Type 1 with higher residual proximal Cobb angle, Type 2 with lower T5-T12 kyphosis and highest pelvic incidence-lordosis mismatch, and Type 3 with larger lumbar curve magnitude and rotation compared to the other two groups. More than 50% of patients in each of the 3D pre-operative clusters had the same post-operative group.

CONCLUSION

We developed a 3D classification of the AIS patients before and two-year after spinal fusion surgery. The link between the pre- and post-operative clusters lends itself to application of this classification system in developing predictive models of the AIS surgical outcomes.

Sagittal curvature of the spine as a predictor of the pediatric spinal deformity development

BACKGROUND

The sagittal curvature of the spine is hypothesized to play an important role in induction of spinal deformities in adolescent idiopathic scoliosis. We previously showed an S shaped flexible rod, with the same curvature as the pediatric sagittal spinal curve, produces scoliotic-like deformities under physiologic loading. Yet, detailed characteristics of the pediatric sagittal spinal curves associated with higher risk of scoliosis are not well defined.

METHODS

A total of 32 patients in a population with a high prevalence of idiopathic-like scoliosis, 22q11.2 deletion syndrome (22q), were included and followed up for at least two-years. We developed a reduced order finite element model (FEM) of the sagittal profile of these 32 patients where the spine was modeled as an S shaped elastic rod. We related the geometrical parameters of the sagittal curves and the deformed FEM of the corresponding S shaped rods to the risk of scoliosis development at two-year follow-up in this cohort.

RESULTS

Variations in the sagittal curvature in the cohort of 22q patients resulted in five different deformity patterns shown by finite element analyses. Two sagittal plane deformity pattern groups had high rate of scoliosis development (86% and 100%) whereas the other 3 groups had less than 50% rate of scoliosis development (40%, 33%, and 0%). The pre-scoliotic position of the inflection point (where lordosis turns into kyphosis), the ratio of the spinal curvatures above and below the inflection point, and the length of the spinal curve above and below the inflection point were significantly different between the five deformity patterns groups, p < 0.05.

CONCLUSION

Combination of geometrical parameters of the sagittal profile prior to onset of scoliosis can relate to the development of spinal deformity in pediatric population.

True 3D parameters of the spinal deformity in adolescent idiopathic scoliosis

BACKGROUND

Spinal deformities in adolescent idiopathic scoliosis (AIS) are measured on 2D radiographs. Due to the 3D nature of the curve in AIS, such 2D measurements fail to differentiate between the true curve patterns, which in turn may adversly impact the clinical care and surgical planning. The use of 3D models of the spinal radiographs largely remains limited to the 3D measurements of the 2D parameters. The use of the true 3D variables of the spinal curves in describing the differences between the AIS patients is not fully explored.

METHODS

A cohort of 141 Lenke 1 AIS with two-view spinal stereoradiographs and 3D models of the spines were included. The 3D model of the spine was used to determine the spinal centerlines. The writhe and torsion of the 3D centerlines, which, respectively, quantify the coiling and twist of the curve, were calculated using differential geometry. Patients were clustered based on the writhe and torsion values to determine the patient groups with significantly different 3D curve characteristics. The relationship between the writhe and torsion was statistically determined. The distribution of the writhe and torsion groups between the lumbar modifier types was determined.

RESULTS

Two writhe and two torsion clusters were determined. Lumbar orientation of plane of maximum curvature (PMC) was significantly different between the torsion clusters and thoracic and lumbar PMC and thoracic Cobb angles were significantly different between the writhe groups, p < 0.05. More than 50% of the patients had high writhe and low torsion except for Lumbar modifier C that mainly belonged to the low writhe group.

DISCUSSION

Two geometrical parameters of the spinal centerline determine true 3D characteristics of the scoliotic curves. The parameters were complimentary and weakly correlated, quantifying different characteristics of the scoliotic spines.

Machine Learning Predicts the 3D Outcomes of Adolescent Idiopathic Scoliosis Surgery Using Patient-Surgeon Specific Parameters

STUDY DESIGN

Retrospective descriptive, multicenter study.

OBJECTIVE

The aim of this study was to predict the three-dimensional (3D) radiographic outcomes of the spinal surgery in a cohort of adolescent idiopathic scoliosis (AIS) as a function preoperative spinal parameters and surgeon modifiable factors.

SUMMARY OF BACKGROUND DATA

Current guidelines for posterior spinal fusion surgery (PSF) in AIS patients are based on two-dimensional classification of the spinal curves. Despite the high success rate, the prediction of the 3D spinal alignment at the follow-ups remains inconclusive. A data-driven surgical decision-making method that determines the combination of the surgical procedures and preoperative patient specific parameters that leads to a specific 3D global spinal alignment outcomes at the follow-ups can lessen the burden of surgical planning and improve patient satisfaction by setting expectations prior to surgery.

METHODS

A dataset of 371 AIS patients who underwent a PSF with two-year follow-up were included. Demographics, 2D radiographic spinal and pelvic measurements, clinical measurements of the trunk shape, and the surgical procedures were collected prospectively. A previously developed classification of the preoperative global 3D spinal alignment was used as an additional predictor. The 3D spinal alignment (vertebral positions and rotations) at two-year follow-up was used as the predicted outcome. An ensemble learner was used to predict the 3D spinal alignment at two-year follow-up as a function of the preoperative parameters with and without considering the surgeon modifiable factors.

RESULTS

The preoperative and surgical factors predicted three clusters of 3D surgical outcomes with an accuracy of 75%. The prediction accuracy decreased to 64% when only preoperative factors, without the surgical factors, were used in the model. Predictor importance analysis determined that preoperative distal junctional kyphosis, pelvic sagittal parameters, end-instrumented vertebra (EIV) angulation and translation, and the preoperative 3D clusters are the most important patient-specific predictors of the outcomes. Three surgical factors, upper and lower instrumented vertebrae, and the operating surgeon, were important surgical predictors. The role of surgeon in achieving a certain outcome clusters for specific ranges of preoperative T10-L2 kyphosis, EIV angulation and translation, thoracic and lumbar flexibilities, and patient's height was significant.

CONCLUSION

Both preoperative patient-specific and surgeon modifiable parameters predicted the 3D global spinal alignment at two-year post PSF. Surgeon was determined as a predictor of the outcomes despite including 20 factors in the analysis that described the surgical moves. Methods to quantify the differences between the implemented surgeon modifiable factors are essential to improve outcome prediction in AIS spinal surgery.Level of Evidence: 3.

A reduced-order model of the spine to study pediatric scoliosis

The S-shaped curvature of the spine has been hypothesized as the underlying mechanical cause of adolescent idiopathic scoliosis. In earlier work, we proposed a reduced-order model in which the spine was viewed as an S-shaped elastic rod under torsion and bending. Here, we simulate the deformation of S-shaped rods of a wide range of curvatures and inflection points under a fixed mechanical loading. Our analysis determines three distinct axial projection patterns of these S-shaped rods: two loop (in opposite directions) patterns and one Lemniscate pattern. We further identify the curve characteristics associated with each deformation pattern, showing that for rods deforming in a Loop1 shape the position of the inflection point is the highest and the curvature of the rod is smaller compared to the other two types. For rods deforming in the Loop2 shape, the position of the inflection point is the lowest (closer to the fixed base) and the curvatures are higher than the other two types. These patterns matched the common clinically observed scoliotic curves-Lenke 1 and Lenke 5. Our S-shaped elastic rod model generates deformations that are similar to those of a pediatric spine with the same sagittal curvature characteristics and it can differentiate between the clinically observed deformation patterns.

Comparison of different strategies on three-dimensional correction of AIS: which plane will suffer?

PURPOSE

There are distinct differences in strategy amongst experienced surgeons from different 'scoliosis schools' around the world. This study aims to test the hypothesis that, due to the 3-D nature of AIS, different strategies can lead to different coronal, axial and sagittal curve correction.

METHODS

Consecutive patients who underwent posterior scoliosis surgery for primary thoracic AIS were compared between three major scoliosis centres (n = 193). Patients were treated according to the local surgical expertise: Two centres perform primarily an axial apical derotation manoeuvre (centre 1: high implant density, convex rod first, centre 2: low implant density, concave rod first), whereas centre 3 performs posteromedial apical translation without active derotation. Pre- and postoperative shape of the main thoracic curve was analyzed using coronal curve angle, apical rotation and sagittal alignment parameters (pelvic incidence and tilt, T1-T12, T4-T12 and T10-L2 regional kyphosis angles, C7 slope and the level of the inflection point). In addition, the proximal junctional angle at follow-up was compared.

RESULTS

Pre-operative coronal curve magnitudes were similar between the 3 cohorts and improved 75%, 70% and 59%, from pre- to postoperative, respectively (P < 0.001). The strategy of centres 1 and 2 leads to significantly more apical derotation. Despite similar postoperative T4-T12 kyphosis, the strategy in centre 1 led to more thoracolumbar lordosis and in centre 2 to a higher inflection point as compared to centre 3. Proximal junctional angle was higher in centres 1 and 2 (P < 0.001) at final follow-up.

CONCLUSION

Curve correction by derotation may lead to thoracolumbar lordosis and therefore higher risk for proximal junctional kyphosis. Focus on sagittal plane by posteromedial translation, however, results in more residual coronal and axial deformity.

Three-dimensional classification of the Lenke 1 adolescent idiopathic scoliosis using coronal and lateral spinal radiographs

BACKGROUND

Classification of the spinal deformity in adolescent idiopathic scoliosis (AIS) remains two-dimensional (2D) as the spinal radiographs remain the mainstay in clinical evaluation of the disease. 3D classification systems are proposed, however are time consuming. We here aim to evaluate the clinical application of a 3D classification system by the use of only posterior-anterior and lateral radiographs in Lenke 1 adolescent idiopathic scoliosis (AIS).

METHODS

Forty Lenke 1 AIS were classified by five observers following a three-step flowchart, developed based on our previous 3D classification system. This 3D classification characterizes the curve in the frontal and sagittal views and infers the third dimension with rules based on prior data to determine the 3D subtypes of the curve. Repeated rating was performed for 20 randomly selected patients in the same cohort. In addition to the classification by the raters, the 3D model of the spines were generated to determine the actual curve subtype based on the algorithm that was originally used to develop the 3D classification system. The interobserver and intraobserver reliability and the classification accuracy were determined for both 3D and axial classifications of the cohort.

RESULTS

The interobserver reliability was moderate to strong with a kappa value between 0.61-0.89 for 3D and axial classifications. Comparing the mathematical classification and the raters' classification, the classification accuracy among all raters ranged between 56 and 89%.

CONCLUSION

We evaluated the reliability of a previously developed 3D classification system for Lenke 1 AIS patients when only two-view spinal radiographs are available. Radiologists and orthopedic surgeons were able to identify the 3D subtypes of Lenke 1 AIS from the patients' radiographs with moderate to strong reliability. The new 3D classification has the potential to identify the subtypes of the Lenke 1 AIS without a need for quantitative 3D image post-processing.

Global 3D parameter of the spine: application of Călugăreanu-White-Fuller theorem in classification of pediatric spinal deformity

Several classification systems of the spinal curves in adolescent idiopathic scoliosis (AIS) have been developed to guide surgical decision-making. The current classification systems are based on the spinal deformity patterns or deformity magnitudes in one or two anatomical planes. Considering the 3D nature of the spinal deformity in AIS, these classifications fail to capture the spine's curve in its entirety. We proposed a classification based on the axial plane and showed that mathematical analysis of the 3D spinal curve, using differential geometry, supports the differences between the subtypes in this classification system. We calculated the writhe and twist of the entire spinal centerline, elements of the Călugăreanu-White-Fuller theorem, in a cohort of 30 right thoracic AIS patients. We also classified this cohort manually based on the vertebral level at which the direction of vertebral rotation caudal to the thoracic curve changes: Lumbar in Group I (V-shaped axial projection) or thoracolumbar in Group II (S-shaped axial projection). The writhe and twist of the spinal curve were significantly different between these manual classification subgroups. Our manual classification distinguished the axial subgroups of right thoracic AIS supported by mathematical specifications of the entire curve in three dimensions. Graphical abstract.

A Semi-Analytic Elastic Rod Model of Pediatric Spinal Deformity

The mechanism of the scoliotic curve development in healthy adolescents remains unknown in the field of orthopedic surgery. Variations in the sagittal curvature of the spine are believed to be a leading cause of scoliosis in this patient population. Here, we formulate the mechanics of S-shaped slender elastic rods as a model for pediatric spine under physiological loading. Second, applying inverse mechanics to clinical data of the subtypes of scoliotic spines, with characteristic 3D deformity, we determine the undeformed geometry of the spine before the induction of scoliosis. Our result successfully reproduces the clinical data of the deformed spine under varying loads, confirming that the prescoliotic sagittal curvature of the spine impacts the 3D loading that leads to scoliosis.

Idiopathic Scoliosis as a Rotatory Decompensation of the Spine

Many years of dedicated research into the etiology of idiopathic scoliosis have not led to one unified theory. We propose that scoliosis is a mechanical, rotatory decompensation of the human spine that starts in the transverse, or horizontal, plane. The human spine is prone to this type of decompensation because of its unique and individually different, fully upright sagittal shape with some preexistent transverse plane rotation. Spinal stability depends on the integrity of a delicate system of stabilizers, in which intervertebral disc stiffness is crucial. There are two phases in life when important changes occur in the precarious balance between spinal loading and the disc's stabilizing properties: (i) during puberty, when loads and moment arms increase rapidly, while the disc's "anchor," the ring apophysis, matures from purely cartilaginous to mineralized to ultimately fused to the vertebral body, and (ii) in older age, when the torsional stiffness of the spinal segments decreases, due to disc degeneration and subsequent laxity of the fibers of the annulus fibrosus. During these crucial periods, transverse plane vertebral rotation can increase during a relatively brief window in time, either as adolescent idiopathic or degenerative de novo scoliosis. Much more is known of the biomechanical changes that occur during disc aging and degeneration than of the changing properties of the disc during maturation. © 2020 American Society for Bone and Mineral Research (ASBMR).

Contouring the magnetically controlled growing rods: impact on expansion capacity and proximal junctional kyphosis

OBJECTIVE

To quantitatively determine the relationship between the contouring of the magnetically controlled growing rods (MCGR), their expansion capacity and the risk of developing proximal junctional kyphosis in early onset scoliosis (EOS). MCGRs allow gradual expansion and correction of the spinal deformity in EOS while reducing the need for repeated surgeries. As the expansion of the MCGRs is controlled externally, several factors can impact the discrepancy between the intended and actual expansions of the rods. The expansion capacity of the growing rods as a function of the expanded length has been tested in experimental setups; however, no study has evaluated the role of contouring of the MCGRs on its function and long-term surgical outcome.

METHODS

A total of 25 EOS patients, a total of 48 MCGRs, with right thoracic curves, were studied retrospectively. All patients had two view spinal radiographs at pre-operative, after MCGR implantation, and after 6 lengthening visits. The first post-operative radiographs were used to calculate the 3D contour of the MCGR at the proximal end. 2D ultrasound images before and after lengthening visits were used to measure the rod lengthening at each visit. The relationship between the increase in the rod length and rod curvature was determined. Finally, the rod curvature was correlated to the changes in proximal junctional kyphosis (PJK) angle between the pre-operative and the most recent follow-up, i.e., after 6 visits.

RESULTS

The average rod 3D angle at the proximal end was 13.5° ± 9.7° [0°-37.2°]. The overall increased length after six lengthening visits for the rod at the concave side was 18.8 mm and at the convex side was 16.9 mm. 62% of the patients with a contoured rod at the proximal end developed a PJK exceeding 10° whereas in patients with a straight rod PJK occurred in 9.1%.

CONCLUSIONS

Contouring the MCGR impacts both the mechanics of the rod expansion and the prevalence of PJK in EOS patient population.

Predicting clustered weather patterns: A test case for applications of convolutional neural networks to spatio-temporal climate data

Deep learning techniques such as convolutional neural networks (CNNs) can potentially provide powerful tools for classifying, identifying, and predicting patterns in climate and environmental data. However, because of the inherent complexities of such data, which are often spatio-temporal, chaotic, and non-stationary, the CNN algorithms must be designed/evaluated for each specific dataset and application. Yet CNN, being a supervised technique, requires a large labeled dataset to start. Labeling demands (human) expert time which, combined with the limited number of relevant examples in this area, can discourage using CNNs for new problems. To address these challenges, here we (1) Propose an effective auto-labeling strategy based on using an unsupervised clustering algorithm and evaluating the performance of CNNs in re-identifying and predicting these clusters up to 5 days ahead of time; (2) Use this approach to label thousands of daily large-scale weather patterns over North America in the outputs of a fully-coupled climate model and show the capabilities of CNNs in re-identifying and predicting the 4 clustered regimes up to 5 days ahead of time. The deep CNN trained with 1000 samples or more per cluster has an accuracy of 90% or better for both identification and prediction while prediction accuracy scales weakly with the number of lead days. Accuracy scales monotonically but nonlinearly with the size of the training set, e.g. reaching 94% with 3000 training samples per cluster for identification and 93-76% for prediction at lead day 1-5, outperforming logistic regression, a simpler machine learning algorithm, by  ~ 25%. Effects of architecture and hyperparameters on the performance of CNNs are examined and discussed.

3D Deformation Patterns of S Shaped Elastic Rods as a Pathogenesis Model for Spinal Deformity in Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) deformity of the spinal column in pediatric population. The primary cause of scoliosis remains unknown. The lack of such understanding has hampered development of effective preventive methods for management of this disease. A long-held assumption in pathogenesis of AIS is that the upright spine in human plays an important role in induction of scoliosis. Here, the variations in the sagittal curve of the scoliotic and non-scoliotic pediatric spines were used to study whether specific sagittal curves, under physiological loadings, are prone to 3D deformation leading to scoliosis. To this end, finite element models of the S shaped elastic rods, which their curves were derived from the radiographs of 129 sagittal spinal curves of adolescents with and without scoliosis, were generated. Using the mechanics of deformation in elastic rods, this study showed that the 3D deformation patterns of the two-dimensional S shaped slender elastic rods mimics the 3D patterns of the spinal deformity in AIS patients with the same S shaped sagittal spinal curve. On the other hand, the rods representing the non-scoliotic sagittal spinal curves, under the same mechanical loading, did not twist thus did not lead to a 3D deformation. This study provided strong evidence that the shape of the sagittal profile in individuals can be a leading cause of the 3D spinal deformity as is observed in the AIS population.

Application of Low-dose Stereoradiography in In Vivo Vertebral Morphologic Measurements: Comparison With Computed Tomography

BACKGROUND

Though computed tomography (CT) and 3 dimensional (3D) reconstruction of the spine and ribcage are powerful techniques for detailed monitoring of spinal growth and surgical planning of patients, drawbacks can arise. We explored the application of low-dose stereoradiography of the spine to calculate distinct morphologic parameters of the vertebral body in a juvenile patient population with early-onset scoliosis or congenital scoliosis. This study compares the 3D vertebral morphology measurements using low-dose stereoradiography with the currently accepted imaging modality for such measurements, CT scans.

METHODS

A total of 86 vertebrae of 6 patients with early-onset scoliosis and 3 patients with congenital scoliosis, age ranged between 7.8 and 12.5 years, who had both thoracic spine CT scan and low-dose stereoradiography of the spine were included. 3D reconstructions of CT and low-dose stereoradiography were generated. Using previously validated image processing techniques, vertebral anterior (A), posterior (P), left (L), and right (R) heights, superior and inferior endplates depth and width (S-D, I-D, S-W, I-W) were measured on the CTs' 3D reconstructions and were compared with the same parameters measured on low-dose stereoradiography reconstructions using a postprocessing custom code. The agreement between the 2 techniques in measurement of the vertebral morphology was assessed using the Bland-Altman plots.

RESULTS

No significant difference was observed in the A, P, L, R, S-W, and I-W between the stereoradiography and CT measurements (P>0.05). S-D and I-D were significantly greater in low-dose stereoradiography measurements P<0.05. Bland-Altman plots showed an agreement between the stereoradiography and CT techniques in vertebral height measurements (A, P, L, R); however, larger measurement bias and greater limits of agreement in S-D, I-D, S-W, and I-W measurements were shown.

CONCLUSIONS

In vivo measurements of the vertebral heights using low-dose stereoradiography 3D reconstructions were comparable with CT measurements except for the superior and inferior vertebral depths. The low-dose stereoradiography imaging modality and the postprocessing platform can be used for assessment of the vertebral heights and monitoring asymmetric growth in patients undergoing growth-sparing treatment except for the vertebral levels with congenital deformities.

LEVEL OF EVIDENCE

Level IV.

Bone Remodeling and Disc Morphology in the Distal Unfused Spine After Spinal Fusion in Adolescent Idiopathic Scoliosis

BACKGROUND

Morphologic changes in the vertebral body in adolescent idiopathic scoliosis (AIS) have been associated with curve development and progression. Yet, after an AIS spinal surgery, the impact of the global and local spinal realignment on the vertebral body and intervertebral disc morphologic changes, particularly in the distal unfused spine, have not been determined.

QUESTIONS/PURPOSES

To determine the changes in the unfused lumbar vertebrae and disc morphology two years after spinal fusion in AIS patients undergoing selective thoracic fusion (STF).

PATIENTS AND METHODS

A total of 58 patients with Lenke type 1 AIS who underwent STF with a minimum two-year follow-up and 20 nonscoliotic adolescents were included. Biplanar stereoradiography of the spine at preoperative, early postoperative, and two-year follow-up were used to generate 3D models of the spine. Lumbar spine vertebral and intervertebral heights (anterior, posterior, left, and right) and the degree of wedging in the frontal and sagittal plane were calculated in the local coordinate system of the vertebral bodies. The morphology of vertebrae and discs were compared between the pre- and postoperative visits of AIS patients and nonscoliotic controls.

RESULTS

Lumbar lordosis was not statistically different between the pre- and post-operative AIS and controls, p > .05. The contribution of the lumbar vertebral bodies and discs' sagittal wedging to the total L1-L5 lordosis were 20% and 80%, respectively, for nonscoliotic controls and 61% and 39%, respectively, for AIS patients at two-year follow-up. The decrease in the anterior and left heights of the disc between the preoperative and two-year follow-up was significant, p < .05.

CONCLUSION

Patients undergoing STF for Lenke 1 AIS are able to achieve normal lumbar lordosis after surgery but seem to regain their sagittal alignment by morphologic changes in the disc more so than the vertebral body. A larger contribution of the vertebral sagittal wedging to the total lumbar lordosis at two years post STF was observed when these variables were compared to the nonscoliotic adolescents.

LEVEL OF EVIDENCE

Level IV.

3D spinal and rib cage predictors of brace effectiveness in adolescent idiopathic scoliosis

Background

Scoliotic braces are the standard of curve for management of moderate spinal deformities in pediatric patients. The effectiveness of this treatment method has been shown; however, the spinal and rib cage parameters, in the three anatomical planes, that are associated with bracing outcome in adolescent idiopathic scoliosis (AIS) are not fully identified.

Methods

A total number of 45 right thoracic AIS patients who had received a thoraco-lumbo-scaral brace for the first time were included retrospectively. For each patient, radiographic images at three visits, pre-brace, in-brace, and at least 1 year after the first brace fit were included. Age, sex, Risser sign, and curve type at pre-brace, and thoracic and lumbar frontal and sagittal Cobb angles, thoracic and lumbar apical rotations, sagittal and frontal balances at pre-brace and in-brace were determined. Two sagittal curve types (hypothoracolumbar and normal/hyperthoracolumbar kyphosis), two rib cage types based on the costovertebral joints (drooping and horizontal), and two axial shapes of the spine (S shaped and V shaped) were used to stratify the patients. Feature selection and linear regression with regularization determined the parameters and the interaction terms that predicted the brace effectiveness significantly.

Results

Smaller in-brace thoracic Cobb and larger in-brace lordosis predicted brace effectiveness, p < 0.05. Impact of the out of brace lordosis on the brace success increased as the in brace kyphosis angle decreased, p = 0.046. A larger out of brace lordosis in hypothoracolumbar sagittal profile type patients improved the outcomes, p = 0.031. A smaller out of brace thoracic rotation improved the bracing outcomes in patients with horizontal ribs, p = 0.040.

Conclusion

Both 3D patient specific parameters (lordosis, thoracic rotation, shape of the rib cage, and sagittal profile) and brace design (which allows larger in brace lordosis, better in brace Cobb correction) are important predictors of the brace effectiveness in AIS.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2754-2) contains supplementary material, which is available to authorized users.

Adolescent Idiopathic Scoliosis Care in an Underserved Inner-City Population: Screening, Bracing, and Patient- and Parent-Reported Outcomes

STUDY DESIGN

Retrospective review of a prospectively collected database.

OBJECTIVES

This preliminary investigation sought to identify the quality of care adolescent idiopathic scoliosis (AIS) patients from our large, underserved community had received before presenting at this institution's clinic.

SUMMARY OF BACKGROUND DATA

AIS affects 1% to 4% of children between ages 10 and 16. Barriers to health care for patients in underserved populations have not been well studied.

METHODS

Patients who visited a single surgeon's clinic for primary AIS between June 2016 and January 2017 were enrolled. Patients had 36-inch full-spine radiographs and completed a survey of demographics, prior AIS care received (screening, bracing, etc), socioeconomic parameters, and patient-reported outcomes (PROs; Scoliosis Research Society [SRS]-30 Questionnaire and Body Image Disturbance Questionnaire [BIDQ]). Parametric and nonparametric analyses were used and percentages and mean/median values were reported.

RESULTS

47 patients (age: 15 ± 3 years; 82.7% female) were included. Overall, 25.5% of patients reported a family history of scoliosis, and 42.6% had no prior knowledge of scoliosis. Per Scoliosis Research Society (SRS) recommendations, 15 patients required observation (main Cobb angle: <25°), 22 patients were eligible for bracing (25°-45°), and 10 patients were surgical candidates (>45°). In addition, 21.3% of all patients were never screened for scoliosis; of these, 50% had a main scoliosis curve >25°. Seventy percent of surgical candidates never wore a brace, and 59.3% of screened patients who were eligible for bracing were not braced at initial presentation. Patients who were left unbraced when eligible exhibited worse BIDQ scores (1.7 vs. 1.4, p < .05).

CONCLUSIONS

One of five children in our population was never screened for scoliosis, and nearly three of five children did not receive optimal care as recommended by SRS. AIS patients in our inner-city populations are potentially at risk of continuing to experience a significant disadvantage in health care access.

LEVEL OF EVIDENCE

Level IV case series.

A hierarchical classification of adolescent idiopathic scoliosis: Identifying the distinguishing features in 3D spinal deformities

This study aimed to identify the differentiating parameters of the spinal curves’ 2D projections through a hierarchical classification of the 3D spinal curve in adolescent idiopathic scoliosis (AIS). A total number of 103 right thoracic left lumbar pre-operative AIS patients were included retrospectively and consecutively. A total number of 20 non-scoliotic adolescents were included as the control group. All patients had biplanar X-rays and 3D reconstructions of the spine. The 3D spinal curve was calculated by interpolating the center of vertebrae and was isotropically normalized. A hierarchical classification of the normalized spinal curves was developed to group the patients based on the similarity of their 3D spinal curve. The spinal curves’ 2D projections and clinical spinal measurements in the three anatomical planes were then statistically compared between these groups and between the scoliotic subtypes and the non-scoliotic controls. A total of 5 patient groups of right thoracic left lumbar AIS patients were identified. The characteristics of the posterior-anterior and sagittal views of the spines were: Type 1: Normal sagittal profile and S shape axial view. T1 is leveled or tilted to the right in the posterior view. Type 2: Hypokyphotic and a V shape axial view. T1 is tilted to the left in the posterior view. Type 3: Hypokyphotic (only T5-T10) and frontal imbalance, S shape axial view. T1 is leveled or tilted to the right, and 3 frontal curves. Type 4: Flat sagittal profile (T1-L2), slight frontal imbalance with a V shape axial view, T1 tilted to the left. Type 5: flat sagittal profile and forward trunk shift with a proximal kyphosis and S shape axial view. T1 is leveled or tilted to the right. In conclusion, a hierarchical classification of the 3D scoliotic spine allowed identifying various distinguishing features of the spinal curves in patients with a right thoracic curve in an orderly fashion. The subtypes’ characteristics resulting from this 3D classification can be identified from the pairs of the frontal and sagittal spinal curves i.e. X-rays in right thoracic AIS patients.

The Link Between the 3D Spino-pelvic Alignment and Vertebral Body morphology in Adolescent Idiopathic Scoliosis

BACKGROUND

Vertebral anterior overgrowth has been suggested as part of the etio-pathogenesis of adolescent idiopathic scoliosis (AIS). However, the link between 3D spinopelvic alignment and the vertebral anteroposterior height asymmetry in different scoliotic curves types and whether it deviates from the non-scoliotic controls, has not been studied.

PURPOSE

We aimed to retrospectively describe the link between the anteroposterior vertebral height differences (ΔAPVH) measured in the true sagittal plane of each vertebra and the spinopelvic parameters in three anatomical planes.

METHODS

30 AIS cases with primary thoracic curves, 28 with thoracolumbar/lumbar curves, and 20 non-scoliotic controls were included. All subjects had 3D reconstruction of the spine, generated from low-dose upright stereoradiography images. Pelvic incidence (PI), thoracic and lumbar coronal and sagittal curve measurements, and vertebral axial rotation were measured. The association between the spinopelvic parameters and ΔAPVH were compared between the two AIS and control groups.

RESULTS

ΔAPVH at the apex of the curve was significantly different between the two AIS groups, as well as between both AIS groups and the controls and was related to the vertebral apical rotation (p < 0.05). Kyphosis and lordosis measurements were significantly related to the sum of the ΔAPVH in thoracic and lumbar regions respectively in AIS group but not in non-scoliotic controls (p < 0.05).

CONCLUSIONS

The ΔAPVH depended on the scoliotic curve type and was significantly different from the controls only at the apical levels. Morphological changes in the scoliotic vertebrae, measured as anterior-posterior differences in the vertebral height, are related to the sagittal spinal profile suggesting the morphology of the vertebra contributes to the sagittal curvatures of the spine in AIS; nonetheless, such relationship between the vertebral morphology and the sagittal profile was not evident in non-scoliotic controls.

Data-driven Classification of the 3D Spinal Curve in Adolescent Idiopathic Scoliosis with an Applications in Surgical Outcome Prediction

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) deformity of the spinal column. For progressive deformities in AIS, the spinal fusion surgery aims to correct and stabilize the deformity; however, common surgical planning approaches based on the 2D X-rays and subjective surgical decision-making have been challenged by poor clinical outcomes. As the suboptimal surgical outcomes can significantly impact the cost, risk of revision surgery, and long-term rehabilitation of adolescent patients, objective patient-specific models that predict the outcome of different treatment scenarios are in high demand. 3D classification of the spinal curvature and identifying the key surgical parameters influencing the outcomes are required for such models. Here, we show that K-means clustering of the isotropically scaled 3D spinal curves provides an effective, data-driven method for classification of patients. We further propose, and evaluate in 67 right thoracic AIS patients, that by knowing the patients’ pre-operative and early post-operation clusters and the vertebral levels which were instrumented during the surgery, the two-year outcome cluster can be determined. This framework, once applied to a larger heterogeneous patient dataset, can further isolate the key surgeon-modifiable parameters and eventually lead to a patient-specific predictive model based on a limited number of factors determinable prior to surgery.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Are we simplifying balance evaluation in adolescent idiopathic scoliosis?

BACKGROUND

Clinical evaluation of the postural balance in adolescent idiopathic scoliosis has been measured by sagittal vertical axis and frontal balance. The impact of the scoliotic deformity in three planes on balance has not been fully investigated.

METHODS

47 right thoracic and left lumbar curves adolescent idiopathic scoliosis and 10 non-scoliotic controls were registered prospectively. 13 spinopelvic postural parameters were calculated from the 3-dimantional reconstructions of X-rays. 7 balance variables describing the position and sway of the center of pressure were recorded using a pressure mat. A regression analysis was used to predict sagittal vertical axis and frontal balance from the 7 balance variables. A canonical correlation analysis was performed between all the postural parameters and balance variables and the significant associations between the postural and balance variables were determined.

FINDINGS

sagittal vertical axis and frontal balance were not significantly associated with the position or sway of the center of pressure (p>0.05). Canonical correlation analysis showed significant associations between the postural variables in the 3 planes and center of pressure position (R²=0.81) and sway (R²=0.62), p<0.05.

INTERPRETATION

Frontal Cobbs, apical rotations, distal kyphosis, pelvic incidence, sacral slope, sagittal vertical axis, and frontal balance contributed to the postural balance in the cohort. The compensatory role of the pelvis and distal kyphosis in sagittal plane was underlined. Multidimensional analyses between the postural and balance variables showed the alignment of the thoracic, lumbar, and pelvis in the 3 planes, in addition to the global head-pelvic position impact on adolescent idiopathic scoliosis balance.

Youth and Experience: The Effect of Surgeon Experience on Outcomes in Cerebral Palsy Scoliosis Surgery

BACKGROUND

Series on the learning curve in spinal deformity surgery have been published, but none has addressed neuromuscular spinal deformity, comprised of arguably the most complex cases. We present the first multi-center analysis of the impact of surgeon experience on neuromuscular spinal deformity surgery.

METHODS

A multi-center prospective study of spinal deformity surgery for cerebral palsy (CP) with at least 2 years of follow-up provided the dataset for assessment. Surgeons were categorized into one of two groups based on their self-reported first year of practice: an experienced surgeons (ES) group included those with at least 10 years of experience at the time of surgery and a young surgeons (YS) group included those with fewer than 10 years of experience at time of surgery. Groups were compared in multiple pre-operative, operative, and post-operative outcomes.

RESULTS

The YS group had 8 surgeons who performed 59 surgeries; the ES group had 13 surgeons who performed 103 cases, with one surgeon's cases distributed in both groups. The YS group had a greater proportion of patients with severe mental retardation (89.7% vs. 68.6%, p = .01). Duration of surgery was greater in the YS group (456 vs. 344 minutes, p < .001). The mean number of levels fused was greater in the ES group (15.9 vs. 15.6, p = .024), caused by increased variation in the upper level of fusion among the ES group. No significant differences were found between groups for estimated blood loss, length of hospitalization, or in percentage of Cobb correction. Years of experience of the operating surgeon was inversely correlated with duration of surgery (rho = -0.476, p < .001).

CONCLUSIONS

In performing scoliosis surgery on CP patients, surgeons with fewer than ten years of practice experience demonstrate significantly greater average operative time and decreased mean number of levels fused, yet produce similar clinical outcomes to more experienced surgeons.

LEVEL OF EVIDENCE

Level III, therapeutic.

Timing of Changes in Three-Dimensional Spinal Parameters After Selective Thoracic Fusion in Lenke 1 Adolescent Idiopathic Scoliosis: Two-Year Follow-up

STUDY DESIGN

Retrospective analysis of the prospectively collected data.

OBJECTIVE

To investigate the relationship between the axial rotation of the unfused lumbar spine and the parameters of the instrumented thoracic spine at varying time points after selective thoracic fusion (STF) in Lenke 1B and 1C adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The impact of STF on the spontaneous lumbar curve correction in AIS has been studied mainly in the frontal planes. The relationship between the spontaneous transverse plane correction of the lumbar spine and the parameters of the fused thoracic spine is not well documented.

METHODS

Twenty-one Lenke 1B and 1C patients who had received STF with minimum two years' follow-up were selected. Thoracic and lumbar Cobb angles, kyphosis, lordosis, and thoracic and lumbar apical vertebrae rotations were measured at preoperative, first-erect, six-month, one-year, and two-year follow-ups. The association between the lumbar apical vertebral rotation and other thoracic and lumbar variables at different time points were determined using regression analysis. The variables significantly predicting the lumbar axial rotation correction at two years were determined from the preceding follow-up visits.

RESULTS

Kyphosis, thoracic Cobb, thoracic apical vertebral rotation, and lumbar Cobb were significantly different between the preoperative and all the postoperative follow-ups (p < .05). At the two-year follow-up, a decrease in thoracic rotation and lumbar Cobb and a higher residual thoracic Cobb were associated with an improved spontaneous lumbar rotation (R² = 0.41, p < .05). Lumbar rotation at two years was predicted from thoracic derotation and lumbar Cobb at first erect (R² = 0.30, p < .05).

CONCLUSION

Spontaneous lumbar curve rotation correction correlated to the fused and unfused spinal parameters in the three anatomic planes. The relationship between thoracic and lumbar rotation persist up to two years after STF. Thoracic derotation is an important factor determining the lumbar rotation correction at two years after STF.

The biomechanical effects of spinal fusion on the sacral loading in adolescent idiopathic scoliosis

BACKGROUND

Posterior spinal surgical correction is performed to correct spinal deformities in adolescent idiopathic scoliosis. Although the relative spino-pelvic alignment changes after spinal surgery, pelvis remains unfused in idiopathic scoliosis surgery. The impact of the spinal fusion on the transferred load to the pelvis via sacrum is not documented in the scoliotic subgroups.

METHOD

Bi-planar radiographs of 9 scoliotic subjects before and in average 16 months after spinal instrumentation surgery, and 12 controls were selected retrospectively. Patient-specific 3D reconstruction and finite element models of the spine, ribcage, and pelvis were developed. Spinal parameters (Cobb angles, kyphosis, lordosis), sacro-pelvic parameters (pelvic incidence, pelvic tilt, sacral slope), frontal and sagittal balances, the position of the trunk center of mass, and the centroid of the stress distribution on the sacrum superior endplate were measured and computed before operation and in the last follow-up.

FINDINGS

The position of the stress distribution centroid on the sacrum superior endplate with respect to the central hip vertical axis was significantly different between pre-operative and post-operative patients p<0.05. The distance between the anterior-posterior position of the trunk center of mass and the center of pressure on the superior sacral endplate significantly decreased after the spinal surgery p<0.05.

INTERPRETATION

The impact of the scoliosis spinal fusion on the transferred load between the spine and pelvis was evaluated. The biomechanical loading of the sacrum endplate was related to the post-operative postural balance and compensatory changes in the spino-pelvic alignment after scoliosis surgery.

Biomechanical loading of the sacrum in adolescent idiopathic scoliosis

BACKGROUND

The pelvis maintains an important role in transferring loads from the upper body to the lower extremities and hence contributes to the standing postural balance. Even though changes in spino-pelvic relative alignment are involved in the pathophysiology of scoliosis, the mechanism through which the transferred load between the spine and pelvis is related to the spinal deformity is not well understood.

METHODS

A personalized finite element model of the spine and pelvis was constructed for 11 right main thoracic and 23 left thoracolumbar/lumbar adolescent idiopathic scoliosis and 12 asymptomatic controls. The compressive stress distribution on the sacrum endplate was computed. The position of the stress distribution barycenter on the sacrum superior endplate in reference to the central hip vertical axis was projected on the transverse plane and compared between scoliotic subgroups and controls.

FINDINGS

The medio-lateral position of the stress distribution barycenter on the sacrum superior endplate was significantly different between the scoliotic subgroups and controls (p<0.05). The stress distribution barycenter on the sacrum superior endplate was located at the right side of the central hip vertical axis in 82% of the right main thoracic patients and to the left side of the central hip vertical axis in 91% of the left thoracolumbar/lumbar patients.

INTERPRETATION

Analysis of the transferred load to the sacrum provided insight into the biomechanical spino-pelvic interaction in 3D, showing that a thoracolumbar/lumbar scoliotic curve has an increased influence on sacral loads when compared to a main thoracic scoliotic curve.

New chiral reverse phase HPLC method for enantioselective analysis of ketorolac using chiral AGP column

A simple, specific, precise, sensitive and rapid reverse phase-HPLC method was developed for determination of ketorolac enantiomers, a potent nonnarcotic analgesic in pharmaceutical formulations. The method was developed on a chiral AGP column. Mobile phase was 0.1 M sodium phosphate buffer (pH 4.5): Isopropanol (98:2, v/v), at a flow rate of 1 mL/min with run time of 15 min. Ultraviolet detection was made at 322 nm. The linearity range was 0.02–10 μg/mL for each of the enantiomers. The mobile phase composition was systematically studied to find the optimum chromatographic conditions. Validation of the method under the conditions selected showed that it was selective and precise and that the detector response was linear function of ketorolac.

Biomechanical analysis of spino-pelvic parameters in adolescent idiopathic scoliosis after spinal instrumentation and fusion: a case study

Posterior spinal fusion and instrumentation is used to correct the spinal deformities in scoliosis. However the effects of this intervention on the biomechanical loading of the distal unfused vertebrae particularly the sacrum are not well documented. The objective of this study was to develop the patient-specific models to simulate the biomechanical loading of the sacrum after operation in AIS subgroups. A detailed personalized finite element model of the spine, pelvis, and ribcage was developed. Biomechanical loading of the sacrum was simulated based on 9 scoliosis patients before surgical instrumentation and in average 16 months after operation, and compared to simulations of 12 controls. No significant difference was observed in the biomechanical loading of the sacrum between post-operative subjects and controls p&gt;0.05 while the biomechanical loading of the sacrum was significantly different between the pre- and post-operative subjects and pre operative subjects and controls p&lt;0.05. These simulations computed the possible effect of the spinal fusion on equilibrating the sacral loading in scoliotic subgroups.

Promoter mutation is a common variant in GJC2-associated Pelizaeus-Merzbacher-like disease

Pelizaeus-Merzbacher-like disease (PMLD) is a clinically and genetically heterogeneous neurological disorder of cerebral hypomyelination. It is clinically characterised by early onset (usually infantile) nystagmus, impaired motor development, ataxia, choreoathetoid movements, dysarthria and progressive limb spasticity. We undertook autozygosity mapping studies in a large consanguineous family of Pakistani origin in which affected children had progressive lower limb spasticity and features of cerebral hypomyelination on MR brain imaging. SNP microarray and microsatellite marker analysis demonstrated linkage to chromosome 1q42.13-1q42.2. Direct sequencing of the gap junction protein gamma-2 gene, GJC2, identified a promoter region mutation (c.-167A>G) in the non-coding exon 1. The c.-167A>G promoter mutation was identified in a further 4 individuals from two families (who were also of Pakistani origin) with clinical and radiological features of PMLD in whom previous routine diagnostic screening of GJC2 had been reported as negative. A common haplotype was identified at the GJC2 locus in the three mutation-positive families, consistent with a common origin for the mutation and likely founder effect. This promoter mutation has only recently been reported in GJC2-PMLD but it has been postulated to affect the binding of the transcription factor SOX10 and appears to be a prevalent mutation, accounting for ~29% of reported patients with GJC2-PMLD. We propose that diagnostic screening of GJC2 should include sequence analysis of the non-coding exon 1, as well as the coding regions to avoid misdiagnosis or diagnostic delay in suspected PMLD.

Identification of a serine protease as a major allergen (Per a 10) of Periplaneta americana

BACKGROUND

Cockroach allergens are associated with the development of asthma, but none of these has been characterized for proteolytic activity. This study was undertaken to isolate and characterize a protease from Periplaneta americana and determine its allergenicity.

METHODS

A serine protease was isolated from P. americana extract using benzamidine sepharose column and characterized by immunobiochemical methods. Allergenicity of the protease was assessed by enzyme-linked immunosorbent assay, immunoblot, intradermal testing, histamine release and peripheral blood mononuclear cells (PBMCs) proliferation.

RESULTS

Affinity purified protein of approximately 28 kDa (Per a 10) showed a single band of activity in gelatin zymogram and agarose plate assay. N-terminal sequence (IVGGRPAQI) revealed similarity with mite serine protease allergens and insect trypsins. It demonstrated proteolytic activity with azocollagen > gelatin > defatted-milk > casein including serine protease specific substrate, N-benzoyl-arginine-ethyl-ester-hydrochloride. It was inhibited by serine protease inhibitors, namely aprotinin > pefabloc > AEBSF > PMSF > benzamidine > antipain > leupeptin and trypsin-specific inhibitor (tosyl-lysyl-chloromethyl-ketone) suggesting it to be a trypsin-like serine protease. Per a 10 was recognized as a major allergen, showing IgE reactivity with >80% of cockroach sensitized patients by skin tests and immunoblot. It could induce significant histamine release (P < 0.05) in blood and secretion of interleukin-4 (IL-4) (P < 0.05) and IL-5 (P < 0.05) in culture supernatant of PBMCs from cockroach hypersensitive patients, suggesting a strong allergenic potency.

CONCLUSION

A serine protease isolated from P. americana was demonstrated to be a major allergen (Per a 10). It has a potential for component-based diagnosis of allergy and will be useful in elucidating the mechanism of allergy.

An antifungal protein from Escherichia coli

A cytosolic protein was purified fromEscherichia coliBL21 that demonstrated potent antifungal activity against pathogenic strains ofAspergillus fumigatus,Aspergillus flavus,Aspergillus nigerandCandida albicans. The MIC of purified protein fromE. coliBL21 (PPEBL21) againstAspergillusspecies andC. albicanswas 1.95–3.98 and 15.62 μg ml−1, respectively.In vitrotoxicity tests demonstrated no cytotoxicity of PPEBL21 to human erythrocytes up to the tested concentrations of 1250 μg ml−1. Amphotericin B was lethal to 100 % of human erythrocytes at a concentration of 37.5 μg ml−1. The N-terminal amino acid sequence of PPEBL21 was found to be DLAEVASR, which showed 75 % sequence similarity with alcohol dehydrogenase of yeast. Mass fingerprinting by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry also substantiated these observations. The results suggested thatE. coliBL21 might be an important bioresource of lead molecules for developing new peptide-based therapies for treating fungal infections.

Morphometric assessment of the oxygen diffusion conductance in placentae from pregnancies complicated by intra-uterine growth restriction

The morphometric oxygen diffusive conductance (D(p)) of the placenta provides a measure of the efficiency of oxygen transfer between the mother and the developing fetus. Any change in the D(p)may point towards possible adaptation in the light of altered oxygen transfer. Placentae from normal (n=40) and small for gestational age SGA (n=24) pregnancies were analysed using stereological techniques. Each placenta was uniform randomly sampled and tissue samples processed to wax infiltration and embedding using conventional histological preparatory methods. A combination of stereological techniques and physiological constants were used to estimate the partial conductances across the five major tissue compartments involved in oxygen transfer. There was a significant reduction in both fetal birthweight and placental weight in the SGA group when compared with controls. A decrease in both chorionic (S(cv)) and fetal capillary (S(fc)) surface area was also observed in SGA placentae when compared with controls (P>0.001). Villous membrane harmonic thickness (T(vm)) was reduced in the SGA placentae (2.33 microm) when compared with controls (2.67 microm P=0.019). This resulted in a reduction in the minimum D(p)in SGA placentae when compared with controls (P=0.023). Adjusting for fetal weight resulted in no difference in the specific diffusive conductance. Changes in T(vm)in SGA placentae combined with changes in basic surface areas were insufficient to maintain overall D(p)values comparable with control placentae.

Effects of intracerebroventricularly administered chimeric peptide of metenkephalin and FMRFa--[D-Ala2]YFa-on antinociception and its modulation in mice

An enzymatically stable analog of YGGFMKKKFMRFamide (YFa), a chimeric peptide of metenkephalin and FMRFa, was synthesised. The antinociceptive effects of intracerebroventricular injections of this analog-[D-Ala2)]YAGFMKKKFMRFamide ([D-Ala2]YFa)-was then investigated using the mouse radiant-heat tail-flick test. [D-Ala2]YFa produced modest to good antinociception at 1, 2, and 5 microg/mouse (0.64, 1.28, and 3.22 nmol, respectively). This antinociceptive effect was completely reversed by the opioid receptor antagonist naloxone (1.5 microg/mouse: 4.12 nmol, intracerebroventricular [i.c.v.]), administered 5 min prior. Pretreatment (5 min) with either neuropeptides FF (1 microg/mouse: 0.92 nmol, i.c.v.) or FMRFa (1 microg/mouse: 1.69 nmol, i.c.v.) significantly attenuated the antinociceptive effects induced by [D-Ala2]YFa (1 microg/mouse, i.c.v.). Intracerebroventricular administration of [D-Ala2]YFa at 1 microg/mouse dose with morphine (2 microg/mouse: 5.86 nmol, i.c.v.) produced an additive antinociceptive effect, suggesting that [D-Ala2]YFa may have a modulatory effect on opioid (morphine) analgesia. These results provide further support for a role of such amphiactive sequences in antinociception and its modulation.

Fusarium solani major allergen peptide IV-1 binds IgE but does not release histamine

BACKGROUND

Fusarium solani (FS) is an important allergen source afflicting 4% of the nasobronchial allergy patients. Fus s I3596*, a 65 kDa major glycoprotein allergen of FS reacts with 95% fungus sensitive patients.

OBJECTIVES

To purify and characterize a potent peptide from Fus s I3596* which may be useful for therapeutic purposes.

METHODS

The 65 kDa protein was sequentially cleaved with trypsin and cyanogen bromide (CNBr). The cleaved products were purified on reverse phase high performance liquid chromatography (rpHPLC) column and functionally characterized by in vitro and in vivo methods for its IgE binding and histamine release.

RESULTS

The protein on cleavage showed 11 peaks (I to XI). Of these, peaks I, III, IV and V were highly allergenic as determined by IgE ELISA. These peaks were further purified and peptide IV-1 was most potent in comparison to other peptides by ELISA-inhibition. This peptide showed IgE binding but could not evoke intradermal response in Fusarium-sensitive patients. Heparinized blood challenged with peptide IV-1 does not release histamine. Preincubation of heparinized blood with peptide IV-1 and challenging with crude extract blocked histamine release in a dose dependent manner.

CONCLUSION

Peptide IV-1 binds to IgE but does not release histamine, demonstrating its potential use in therapy of Fusarium-allergic patients.

Effects of intracerebroventricularly administered chimeric peptide of metenkephalin and FMRFa--[D-Ala2]YFa-on antinociception and its modulation in mice

An enzymatically stable analog of YGGFMKKKFMRFamide (YFa), a chimeric peptide of metenkephalin and FMRFa, was synthesised. The antinociceptive effects of intracerebroventricular injections of this analog-[D-Ala2)]YAGFMKKKFMRFamide ([D-Ala2]YFa)-was then investigated using the mouse radiant-heat tail-flick test. [D-Ala2]YFa produced modest to good antinociception at 1, 2, and 5 microg/mouse (0.64, 1.28, and 3.22 nmol, respectively). This antinociceptive effect was completely reversed by the opioid receptor antagonist naloxone (1.5 microg/mouse: 4.12 nmol, intracerebroventricular [i.c.v.]), administered 5 min prior. Pretreatment (5 min) with either neuropeptides FF (1 microg/mouse: 0.92 nmol, i.c.v.) or FMRFa (1 microg/mouse: 1.69 nmol, i.c.v.) significantly attenuated the antinociceptive effects induced by [D-Ala2]YFa (1 microg/mouse, i.c.v.). Intracerebroventricular administration of [D-Ala2]YFa at 1 microg/mouse dose with morphine (2 microg/mouse: 5.86 nmol, i.c.v.) produced an additive antinociceptive effect, suggesting that [D-Ala2]YFa may have a modulatory effect on opioid (morphine) analgesia. These results provide further support for a role of such amphiactive sequences in antinociception and its modulation.

Effects of intracerebroventricularly administered chimeric peptide of metenkephalin and FMRFa--[D-Ala2]YFa-on antinociception and its modulation in mice

An enzymatically stable analog of YGGFMKKKFMRFamide (YFa), a chimeric peptide of metenkephalin and FMRFa, was synthesised. The antinociceptive effects of intracerebroventricular injections of this analog-[D-Ala2)]YAGFMKKKFMRFamide ([D-Ala2]YFa)-was then investigated using the mouse radiant-heat tail-flick test. [D-Ala2]YFa produced modest to good antinociception at 1, 2, and 5 microg/mouse (0.64, 1.28, and 3.22 nmol, respectively). This antinociceptive effect was completely reversed by the opioid receptor antagonist naloxone (1.5 microg/mouse: 4.12 nmol, intracerebroventricular [i.c.v.]), administered 5 min prior. Pretreatment (5 min) with either neuropeptides FF (1 microg/mouse: 0.92 nmol, i.c.v.) or FMRFa (1 microg/mouse: 1.69 nmol, i.c.v.) significantly attenuated the antinociceptive effects induced by [D-Ala2]YFa (1 microg/mouse, i.c.v.). Intracerebroventricular administration of [D-Ala2]YFa at 1 microg/mouse dose with morphine (2 microg/mouse: 5.86 nmol, i.c.v.) produced an additive antinociceptive effect, suggesting that [D-Ala2]YFa may have a modulatory effect on opioid (morphine) analgesia. These results provide further support for a role of such amphiactive sequences in antinociception and its modulation.

Peptide models for inherited neurodegenerative disorders: conformation and aggregation properties of long polyglutamine peptides with and without interruptions

Several neurodegenerative diseases are caused by expansion of polyglutamine repeats in the affected proteins. In spino-cerebellar ataxia type 1 (SCA1), histidine interruptions have been reported to mitigate the pathological effects of long glutamine stretches. To understand this phenomenon, we investigated the conformational preferences of peptides containing both the uninterrupted polyglutamine stretches and those with histidine interruption(s) as seen in SCA1 normals. Our study suggests that substitution of histidines by glutamines induces a conformational change which results in decreased solubility and increased aggregation. Our findings also suggest that all the polyglutamine peptides with and without interruption(s) adopt a beta-structure and not random coil.

Chimeric peptide of Met-enkephalin and FMRFa induces antinociception and attenuates development of tolerance to morphine antinociception

A synthetic chimeric peptide of Met-enkephalin and FMRFamide (YGGFMKKKFMRFa), based on MERF was synthesized. This peptide was tested for possible antinociceptive effects using the tail flick test in mice. The effect of the chimeric peptide on morphine antinociception and development of tolerance to the antinociceptive action of morphine was also investigated. The chimeric peptide produced significant, dose-dependent antinociception (40, 60 and 90 mg/kg) in the tail flick test. Pretreatment with naloxone (5 mg/kg, IP) significantly attenuated the antinociceptive effect induced by the chimeric peptide (90 mg/kg, IP), indicating involvement of an opioidergic mechanism. In combination experiments with morphine, the antinociceptive dose of the chimeric peptide (60 mg/kg, IP) potentiated morphine (7 mg/kg, IP) antinociception. A low dose of the chimeric peptide (10 mg/kg, IP), that did not produce significant antinociception on its own, also potentiated morphine antinociception. In the tolerance studies, male albino mice received twice daily injections of morphine (20 mg/kg, IP) followed by either saline (0.1 ml) or chimeric peptide (80 mg/kg, IP) for a period of 4 days. A control group received twice daily injections of saline (0.1 ml) for the same period. When tested on Day 5, tolerance to antinociceptive action of morphine (15 mg/kg, IP) was evidenced by decreased response in chronic morphine plus saline treated mice compared to control group. Concurrent administration of chimeric peptide (80 mg/kg, IP) with morphine significantly attenuated the development of tolerance to the antinociceptive action of morphine. The preliminary results of this study demonstrate that peripherally administered chimeric peptide can produce dose dependent, naloxone reversible, antinociception; potentiate morphine antinociception and attenuate morphine tolerance, indicating a possible role of these type of amphiactive sequences in antinociception and its modulation. These chimeric peptides may also prove to be useful tools for further ascertaining the role of FMRFa family of peptides in mechanisms leading to opiate tolerance and dependence.

Purification and characterization of Fus sI3596*, a 65 kd allergen of Fusarium solani

A component of Fusarium solani (F. solani), identified as the major allergen, Fus sI3596* was purified to homogeneity from culture filtrate (CF) by means of anion-exchange column chromatography, gel filtration and FPLC. The homogeneity of Fus sI3596* was assessed by IEF, PAGE, SDS-PAGE (non-reducing), immunoblot and HPLC. Fus sI3596* was isolated as a glycoprotein of MW 65 kd and pI 3.6. The IgE ELISA-inhibition assay after periodate treatment of the fraction showed a lower IgE binding capacity suggesting involvement of carbohydrate moiety in IgE binding reactions of the allergen. Peptide fragments of Fus sI3596* obtained after CNBr and trypsin treatment were analysed by immunoblotting for their allergenicity. This study indicated that there could be at least 3 allergenic determinants in the major allergen, Fus sI3596* of F. solani CF.