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Background: Virtual and augmented reality surgical simulators, integrated with machine learning, are becoming essential for training psychomotor skills, and analyzing surgical performance. Despite the promise of methods like the Connection Weights Algorithm, the small sample sizes (small number of participants (N)) typical of these trials challenge the generalizability and robustness of models. Approaches like data augmentation and transfer learning from models trained on similar surgical tasks address these limitations., Objective: To demonstrate the efficacy of artificial neural network and transfer learning algorithms in evaluating virtual surgical performances, applied to a simulated oblique lateral lumbar interbody fusion technique in an augmented and virtual reality simulator., Design: The study developed and integrated artificial neural network algorithms within a novel simulator platform, using data from the simulated tasks to generate 276 performance metrics across motion, safety, and efficiency. Innovatively, it applies transfer learning from a pre-trained ANN model developed for a similar spinal simulator, enhancing the training process, and addressing the challenge of small datasets., Setting: Musculoskeletal Biomechanics Research Lab; Neurosurgical Simulation and Artificial Intelligence Learning Centre, McGill University, Montreal, Canada., Participants: Twenty-seven participants divided into 3 groups: 9 post-residents, 6 senior and 12 junior residents., Results: Two models, a stand-alone model trained from scratch and another leveraging transfer learning, were trained on nine selected surgical metrics achieving 75 % and 87.5 % testing accuracy respectively., Conclusions: This study presents a novel blueprint for addressing limited datasets in surgical simulations through the strategic use of transfer learning and data augmentation. It also evaluates and reinforces the application of the Connection Weights Algorithm from our previous publication. Together, these methodologies not only enhance the precision of performance classification but also advance the validation of surgical training platforms., Competing Interests: Declaration of competing interest “None declared”., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: The purpose of this study is to compare both perioperative as well as long-term outcomes of patients undergoing carotid endarterectomy (CEA) for asymptomatic carotid bifurcation stenosis based on duplex ultrasound in isolation relative to a combination of duplex and more advanced imaging., Methods: All CEA in the VQI between January 2003 and May 2022 were queried. We identified 171,816 CEAs in the database. Exclusions were symptomatic carotid lesion (57,742), lack of imaging documentation (908), lack of advanced imaging status (1,816), simultaneous additional arterial intervention in the carotid, coronary, or peripheral arterial system (n = 4,118), and anatomic high-risk status for CEA (n = 4,071). Included patients were then placed into 1 of 2 cohorts: patients undergoing CEA based on duplex imaging alone (n = 33,437) and those undergoing CEA based on advanced imaging (CTA, MRA, or invasive angiography) with or without duplex (n = 69,715). We performed multivariable analysis for the following outcomes utilizing CEA based on duplex in isolation as 1 of the variables: perioperative neurological ischemic event utilizing binary logistic regression; combined 90-day mortality and neurological ischemic event utilizing binary logistic regression; neurological event in long-term follow-up with date of surgery serving as time zero; time dependent Cox regression analysis; mortality in long-term follow-up utilizing time-dependent Cox regression., Results: Carotid endarterectomy based on duplex alone and CEA based on advanced imaging had essentially equivalent rates of 90-day mortality (0.9% vs. 1.0%, P = 0.108); combined perioperative neurological event and 90-day mortality (2.0% vs. 2.2%, P = 0.042); and, return to the operating room (1.6% vs. 1.7%, P = 0.154). On multivariable analysis CEA based on advanced imaging was noted to have a slightly higher absolute rate of perioperative neurological event without achieving multivariable significance (1.3% vs. 1.2%, adjusted odds ratio 1.11 (0.98-1.25), P = 0.092. CEA based on advanced imaging had a higher rate of neurological event after index hospital admission relative to duplex in isolation (hazard ratio (HR) 1.44 (1.31-1.60), P < 0.001). However, the absolute percentage difference was just 0.5% (1.6% vs. 2.1%). CEA based on duplex alone was associated with a slightly increased risk of mortality in LTFU (HR 1.16 (1.11-1.21), P < 0.001). At 5 years the absolute risk of mortality was less than 1% different between the cohorts., Conclusions: Performing CEA for asymptomatic bifurcation stenosis based on duplex ultrasound alone is a safe practice which achieves clinically equivalent perioperative and long-term freedom from cerebral ischemia and mortality relative to CEA based on advanced imaging. This has potential implications for health care cost saving as well as avoidance of radiation and iodinated contrast., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Surgical simulators are being introduced as training modalities for surgeons. This paper aims to evaluate dynamic models used to convey force feedback from puncturing the soft tissue during a spine surgical simulation. The force feedback of the tissue is treated as a dynamic system. This is done by performing classical system identification across a bandwidth of frequencies on a tissue analogue and fitting that behaviour to dynamic viscoelastic models. The models that are tested are an inverted linear model, the Maxwell model, the Kelvin-Boltzmann (KB) model, and a higher-order blackbox (HO) model. Several error metrics such as percent variance accounted for (%VAF) are determined to measure solution accuracy. The force feedback models are programmed into a surgical simulator and tested with study participants who rated them based on how well the identified models match the behaviour of the rubber tissue analogue. The highest %VAF is 82.64% when the tissue is modelled as the HO model. Statistically significant differences (p < 0.05) are found between all model ratings from participants except between the HO model and the KB model. However, the HO model has the highest percentage (37.8%) of participants who rank its performance as the closest to the tissue analogue compared to the other force feedback models. The more accurately the dynamic behaviour resembles the tissue analogue, the higher the model was rated by study participants. This study highlights the importance of utilizing dynamic signals to generate dynamic models of soft tissue for spine surgical simulators., Competing Interests: Declaration of competing interest None Declared, (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: The geometric alignment of the spine plays an integral role in stability, biomechanical loading, and consequently, pain, and a range of healthy sagittal curvatures has been identified. Spinal biomechanics when sagittal curvature is outside the optimal range remains a debate and may provide insight into the load distribution throughout the spinal column., Method: A thoracolumbar spine model (Healthy) was developed. Thoracic and lumbar curvatures were adjusted by 50% to create models with varying sagittal profiles: hypolordotic (HypoL), hyperlordotic (HyperL), hypokyphotic (HypoK), and hyperkyphotic (HyperK). In addition, lumbar spine models were constructed for the former three profiles. The models were subjected to loading conditions simulating flexion and extension. Following validation, intervertebral disc stresses, vertebral body stresses, disc heights, and intersegmental rotations were compared across all models., Results: Overall trends demonstrated that HyperL and HyperK models had a noticeable reduction in disc height and greater vertebral body stresses compared to the Healthy model. In comparison, the HypoL and HypoK models displayed opposite trends. Considering the lumbar models, the HypoL model had reduced disc stresses and flexibility, while the contrary was observed in the HyperL model. Results indicate that the models with excessive curvature may be subjected to greater stress magnitudes, while the straighter spine models may reduce these stresses., Conclusions: Finite element modeling of spine biomechanics demonstrated that variations in sagittal profiles influence the load distribution and range of motion of the spine. Considering patient-specific sagittal profiles in finite element modeling may provide valuable insight for biomechanical analyses and targeted treatments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: To determine if women Veterans who deployed in support of Operations Enduring Freedom/Iraqi Freedom (OEF/OIF) would show a greater likelihood of breast cancer (BC) than other women Veterans., Methods: This was a retrospective cohort study of women aged <60 years who received Veterans Affairs medical center primary care, 2001-2021. The exposure was OEF/OIF deployment and the outcome was a BC diagnosis after entering Veterans Affairs care. Poisson models evaluated the association between deployment and BC incidence, covarying demographics, lifestyle factors, and hormonal contraceptive and hormone replacement therapy use. Analyses were also stratified by age and race, and a sensitivity analysis adjusted for healthcare utilization over the initial 2 years., Results: Of 576,601 women, 24.6% (n = 141,935) deployed during post-9/11 conflicts. Across follow-up [median: 8.2 years], 1.2% women were diagnosed with BC. Those who deployed in support of OEF/OIF were 23% less likely to be diagnosed with BC than women who did not deploy (95% CI: 0.73, 0.86). The association remained in stratified models and when including healthcare utilization., Conclusions: Despite the exposures of OEF/OIF deployment, there was a significantly lower incidence of BC among women who deployed versus not, possibly due to a healthy soldier effect or to differences in screening., (Copyright © 2022. Published by Elsevier Inc.)

Background: Current spine models for analog bench models, surgical navigation and training platforms are conventionally based on 3D models from anatomical human body polygon database or from time-consuming manual-labelled data. This work proposed a workflow of quick and accurate subject-specific vertebra reconstruction method and quantified the reconstructed model accuracy and model form errors., Methods: Four different neural networks were customized for vertebra segmentation. To validate the workflow in clinical applications, an excised human lumbar vertebra was scanned via CT and reconstructed into 3D CAD models using four refined networks. A reverse engineering solution was proposed to obtain the high-precision geometry of the excised vertebra as gold standard. The 3D model evaluation metrics and a finite element analysis (FEA) method were designed to reflect the model accuracy and model form errors., Results: The automatic segmentation networks achieved the best Dice score of 94.20% in validation datasets. The accuracy of reconstructed models was quantified with the best 3D Dice index of 92.80%, 3D IoU of 86.56%, Hausdorff distance of 1.60 mm, and the heatmaps and histograms were used for error visualization. The FEA results showed the impact of different geometries and reflected partial surface accuracy of the reconstructed vertebra under biomechanical loads with the closest percentage error of 4.2710% compared to the gold standard model., Conclusions: In this work, a workflow of automatic subject-specific vertebra reconstruction method was proposed while the errors in geometry and FEA were quantified. Such errors should be considered when leveraging subject-specific modelling towards the development and improvement of treatments., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Optimization models are often devised to assess spinal stability via estimating individual muscle forces. However, neglecting muscles' fluidic behavior remains an approximation due to the role of muscle pressure in force transmission. The purpose of this study was to leverage a validated Finite Element (FE) model of the spine, inclusive of Intra-Muscular Pressure (IMP), to explore muscle activation strategies towards maintaining equilibrium spinal stability. Three conventional strategies governing minimizing muscle effort, minimizing IVD compressive forces, and maintaining stability at all costs were first investigated to explore model's validity. Thereafter, two novel IMP-based strategies were devised and explored, specifically minimizing and maximizing IMP. The model was previously shown valid in light of in vivo and in silico observations with an average discrepancy of 6%. This being the case, the conventional strategies dictated efficacy in muscular activations whilst maintaining an equilibrium stable position, as quantified in the present paper, with a difference of 9.8% from documented data. In addition, the explored novel IMP-based strategies suggested the presence of a threshold individual muscles IMP, approximately 272 mmHg for the longissimus muscle for example, beyond which muscles potentially start to share radial loads with surrounding tissues, whilst limiting the contraction of the underlying muscles. In conclusion, this study theoretically supports the possibility of activation strategies based on muscular pressure, which the developed, verified, and validated FE spine model was leveraged to investigate. The explored novel IMP-based strategies may have significance in informing clinical applications such as motion analysis and functional electrical stimulation of muscles., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Virtual reality surgical simulators are a safe and efficient technology for the assessment and training of surgical skills. Simulators allow trainees to improve specific surgical techniques in risk-free environments. Recently, machine learning has been coupled to simulators to classify performance. However, most studies fail to extract meaningful observations behind the classifications and the impact of specific surgical metrics on the performance. One benefit from integrating machine learning algorithms, such as Artificial Neural Networks, to simulators is the ability to extract novel insights into the composites of the surgical performance that differentiate levels of expertise., Objective: This study aims to demonstrate the benefits of artificial neural network algorithms in assessing and analyzing virtual surgical performances. This study applies the algorithm on a virtual reality simulated annulus incision task during an anterior cervical discectomy and fusion scenario., Design: An artificial neural network algorithm was developed and integrated. Participants performed the simulated surgical procedure on the Sim-Ortho simulator. Data extracted from the annulus incision task were extracted to generate 157 surgical performance metrics that spanned three categories (motion, safety, and efficiency)., Setting: Musculoskeletal Biomechanics Research Lab; Neurosurgical Simulation and Artificial Intelligence Learning Center, McGill University, Montreal, Canada., Participants: Twenty-three participants were recruited and divided into 3 groups: 11 post-residents, 5 senior and 7 junior residents., Results: An artificial neural network model was trained on nine selected surgical metrics, spanning all three categories and achieved 80% testing accuracy., Conclusions: This study outlines the benefits of integrating artificial neural networks to virtual reality surgical simulators in understanding composites of expertise performance., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Introduction: The pathomechanism of low back pain (LBP) remains unknown. Unilateral LBP patients have demonstrated ipsilateral morphological and material property changes within the lumbar soft tissues, potentially leading to asymmetric tissue loading. Through the comparison of healthy and unilateral LBP validated finite element models (FEMs), this study investigates potential stress shielding consequential of spinal tissue property augmentation., Methods: Two FEMs of the musculoskeletal system - one demonstrating healthy and unilateral LBP conditions - were developed undergoing 30-degree flexion. FEMs included the vertebrae, intervertebral discs, and soft tissues from L1-S1. Material properties selected for the soft tissues were retrieved from published literature. To reflect unilateral LBP, the paraspinal morphology was atrophied, while the tissue moduli were increased. The symptomatic thoracolumbar fascia (TLF) was uniformly increased. Validation of the models preceded testing., Results: Model validation in spinal flexion was accomplished through comparison to literature. Compared to the healthy model, the unilateral LBP multifidus (MF), longissimus thoracis (LT), and TLF exhibited average tension changes of +7.9, -5.1, and +9.3%, respectively. Likewise, the symptomatic MF, LT, and TLF exhibited tension changes of +19.0, -10.4, and +16.1% respectively, whereas the asymptomatic MF, LT, and TLF exhibited -4.0, -2.0, and +0.4% changes in tension, respectively., Conclusion: Relative to the healthy tissues, the symptomatic LBP soft tissues demonstrated a 19.5 kPa increase in stress, with 99.8% of this increase distributed towards the TLF, suggesting a load allocation bias within the symptomatic unilateral LBP tissues. Consequentially, symptomatic paraspinal muscles may be unable to withstand loading, leading to stress shielding., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A new adaptive impedance, augmented with backstepping control, time-delay estimation, and a disturbance observer, was designed to perform passive-assistive rehabilitation motion. This was done using a rehabilitation robot whereby humans' musculoskeletal conditions were considered. This control scheme aimed to mimic the movement behavior of the user and to provide an accurate compensation for uncertainties and torque disturbances. Such disturbances were excited by constraints of input saturation of the robot's actuators, friction forces and backlash, several payloads of the attached upper-limb of each patient, and time delay errors. The designed impedance control algorithm would transfer the stiffness of the human upper limb to the developed impedance model via the measured user force. In the proposed control scheme, active rejection of disturbances would be achieved through the direct connection between such disturbances from the observer's output and the control input via the feedforward loop of the system. Furthermore, the computed control input does not require any precise knowledge of the robot's dynamic model or any knowledge of built-in torque-sensing units to provide the desirable physiotherapy treatment. Experimental investigations performed by two subjects were exhibited to support the benefits of the designed approach., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 ISA. Published by Elsevier Ltd. All rights reserved.)

Background: Patient falls during an acute hospitalization cause injury, reduced mobility, and increased costs. The laminated paper Fall TIPS Toolkit (Fall TIPS) provides clinical decision support at the bedside by linking each patient's fall risk assessment with evidence-based interventions. Strategies were needed to integrate this evidence into clinical practice., Methods: The Institute for Healthcare Improvement's Framework for Spread is the conceptual model for pilot implementation of Fall TIPS at Brigham and Women's Hospital (BWH; Boston) and Montefiore Medical Center (MMC; Bronx, New York). The key to translating the evidence into practice was engaging stakeholders by leveraging existing shared governance structures, identifying unit champions, holding training sessions for all staff, and implementing auditing to assess and provide feedback on protocol adherence and patient outcomes., Results: BWH unit compliance with using Fall TIPS averaged 82%, the mean fall rate decreased from 3.28 to 2.80 falls per 1,000 patient-days from January through June 2015 versus 2016, and the mean fall with injury rate for these periods decreased from 1.00 to 0.54 per 1,000 patient-days. At MMC, compliance averaged 91%, but the mean fall rate increased marginally from 3.04 to 3.10, while the mean fall with injury rate decreased from 0.47 to 0.31 per 1,000 patient-days. Patient knowledge survey results show improvement in knowledge of the risks for falls and the ways to prevent falls., Conclusion: Engaging hospital and clinical leadership is critical in translating evidence-based care into clinical practice. Barriers to adoption of the protocol have been addressed and detailed to provide guidance for spread to other institutions., (Copyright © 2017 The Joint Commission. Published by Elsevier Inc. All rights reserved.)

Hip subluxation in children with Cerebral Palsy (CP) has an incidence of 10-30 %, and children with severe CP having the highest incidence. The condition deteriorates if left untreated. Surgery is the most common method used in managing hip subluxation because standard conservative therapies do not improve it. Surgery may have to be repeated and comes at a biological cost to the child. A new home-based CAM, Advanced Biomechanical Rehabilitation (ABR), has shown encouraging results leading to improved spinal stability and stability in sitting in children with severe CP. This case report examines hip development over time in six children with severe CP in the ABR Program. Changes in their clinical picture and pelvic X-Rays are reported. ABR appeared to help stabilize and improve hip subluxation, resulting in these children not requiring further surgical intervention. These findings warrant further investigation of ABR as a noninvasive therapy for hip subluxation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Infections of domesticated dogs by a worldwide parasitic nematode Filaroides osleri (Oslerus osleri) lead to verminous tracheobronchitis that are often misdiagnosed clinically as kennel cough, due to infection with the bacterium Bordetella bronchiseptica. Diagnosis of two canine cases in Wyoming, USA prompted a search of the literature of canid infections in North America. Infections of domestic dogs are reported in nine US states and four Canadian provinces. Dogs of multiple breeds and both sexes were infected. Most were two years old or younger at diagnosis. Anthelmintic treatments were effective in relieving clinical symptoms, as well as causing resolution of tracheobronchial nodules. Other canid species, including coyotes (Canis latrans) and wolves (Canis lupus), have been infected across North America with a prevalence of 23% and 4%, respectively. Infection with F. osleri should be included in the differential diagnosis of infectious tracheobronchitis of dogs. It can be confirmed most readily by endoscopic detection of distinctive submucosal parasite-filled nodules, combined with histological examination of endoscopic biopsies., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The Extension Family Lifestyle Intervention Project (E-FLIP for Kids) is a three-arm, randomized controlled trial assessing the effectiveness of two behavioral weight management interventions in an important and at-risk population, overweight and obese children and their parents in rural counties. Participants will include 240 parent-child dyads from nine rural counties in north central Florida. Dyads will be randomized to one of three conditions: (a) a Family-Based Behavioral Group Intervention, (b) a Parent-Only Behavioral Group Intervention, and (c) an Education Control Condition. Child and parent participants will be assessed at baseline (month 0), post-treatment (month 12) and follow-up (month 24). Assessment and intervention sessions will be held at Cooperative Extension Service offices within each participating county. The primary outcome measure is change in child BMI z-score. Additional key outcome measures include child body fat, waist circumference, dietary intake, physical activity, blood lipids, blood glucose, blood pressure, physical fitness, quality of life, and program and participants costs. Parent BMI, dietary intake, and physical activity also will be assessed. Randomized controlled trials testing the effectiveness of childhood obesity interventions in real-world community-based settings are extremely valuable, but much too rare. The E-FLIP for Kids trial will evaluate the impact of a community-based intervention delivered to families in rural settings utilizing the existing Cooperative Extension Service network on long-term child behavior, weight status and biological markers of diabetes and early cardiovascular disease. If successful, a Parent-Only intervention program may provide a cost-effective and practical intervention for families in underserved rural communities., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Objectives: Action learning (AL) facilitates reflection, critical thinking, and learning while solving real-world problems. Virtual AL is an asynchronous collaborative process that encourages students to analyze their critical incidents and learn from these experiences. The researchers sought to: 1) determine whether medical students engaged in peer-facilitated virtual action learning (VAL) demonstrated reflection and critical thinking around complex issues during their pediatric clerkship; and 2) identify challenges students face during their clerkships., Methods: Seventy clerkship students were introduced to reflection and participated in VAL by using an electronic discussion board. Each posted 1 critical incident and group members responded with thought-provoking questions and comments to facilitate reflection and analysis. Weekly, students who posted incidents revisited their incidents, pondered the questions posed, and wrote essays summarizing their reflections and insights gained. Data were analyzed using qualitative methods., Results: Seventy incidents, 210 responses, and 70 revised incidents/essays were analyzed. Outcomes included broadened perspectives (44/70), questioned assumptions (12/70), and reconfirmed thinking (14/70). Content themes included communication, role identification, medical treatment concerns, and limited voice and power., Conclusions: Most of the students engaged in VAL demonstrated reflection on complex clinical issues. Themes portrayed struggles encountered and exposed issues in the hidden curriculum, suggesting a lack of voice and power that may lead to missed learning opportunities. Discussion threads offered the clerkship director insights into the overall student experience to improve future clerkship experiences., (Copyright 2010 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.)

Patients with severe immune thrombocytopenic purpura (ITP) may require an acute increase in the platelet count for surgery or ongoing hemorrhage as well as long-term maintenance treatment. Certain of these patients may be refractory to steroids, intravenous anti-D, intravenous immunoglobulin (IVIG), and splenectomy. Therefore, acute platelet increases were studied in 35 patients completely unresponsive to IVIG or high-dose steroid treatment. Because of their lack of response to either or both single agents, these patients were administered a 3- or 4-drug combination including IVIG 1 g/kg, intravenous methylprednisolone 30 mg/kg, Vinca alkaloids (VCR 0.03 mg/kg), and/or intravenous anti-D (50-75 microg/kg). Subsequent maintenance therapy with the oral combination of danazol (10-15 mg/kg) and azathioprine (2 mg/kg) was given to 18 of the 35 patients. Seventy-one percent of the patients responded to the intravenous combination treatment with acute platelet increases of at least 20 x 10(9)/L to a level greater than 30 x 10(9)/L. Two thirds of the patients given maintenance therapy achieved stable platelet counts greater than 50 x 10(9)/L without other treatments. One patient developed an ileus, but otherwise there was little toxicity of combination treatment. Combination chemotherapy is a useful approach for patients with ITP refractory to conventional treatments both for acute induction and for long-term maintenance therapy.

Objective: Reflection enables learners to analyze their experiences and capture the wisdom that lies within. Effective teaching requires reliable methods of assessment. Several methods of assessing reflective writing have been described; however, they often require significant training, and reliability has seldom been assessed. This study was designed to determine the interrater reliability of a method of assessing reflective writing by using a modified Bloom's Taxonomy., Methods: Twenty-one third-year medical students maintained reflective journals throughout their pediatric clerkship. A coding schema based on Bloom's Taxonomy was developed to assess the level of cognitive processing evident in the journals. Journals were independently assessed by 3 raters. Percent agreement, kappa statistics, and intraclass correlation coefficients (ICC [2,1]) were used to assess interrater reliability., Results: Three hundred eight entries from 21 journals were assessed. Percent agreement ranged from 78.2% to 100%. Kappa statistic for each level ranged from 0.57 +/- 0.04 to 0.73 +/- 0.04, and for the highest level of processing evident it ranged from 0.52 +/- .04 to 0.58 +/- 0.04. ICC (2,1) for each level of cognitive processing ranged from 0.62 (F = 6.20; P = .000) to 1.00, and for the highest level of cognitive processing evident, it was 0.79 (F = 12.42; P = .000). Substantial to almost perfect agreement was attained., Conclusions: Reflective journals allow learners to revisit their experiences for critical analysis and deeper learning. This study describes a reliable method, based on Bloom's Taxonomy, of determining whether learners have achieved higher order thinking through reflective journal writing. This method can provide a baseline for facilitating higher order processing, critical thinking, and reflective practice.

Objective: To identify factors associated with resident satisfaction concerning residents' continuity experience., Design and Methods: Continuity directors distributed questionnaires to residents at their respective institutions. Resident satisfaction was defined as satisfied or very satisfied on a Likert scale. The independent variables included 60 characteristics of the continuity experience from 7 domains: 1) patient attributes, 2) continuity and longitudinal issues, 3) responsibility as primary care provider, 4) preceptor characteristics, 5) educational opportunities, 6) exposure to practice management, and 7) interaction with other clinic and practice staff. A stepwise logistic regression model and the Generalized Estimating Equations approach were used., Results: Thirty-six programs participated. Of 1155 residents (71%) who provided complete data, 67% (n = 775) stated satisfaction with their continuity experience. The following characteristics (adjusted odds ratio [OR] and 95% confidence interval [CI]) were found to be most significant: preceptor as good role model, OR = 7.28 ( CI = 4.2, 12.5); appropriate amount of teaching, OR = 3.25 (CI = 2.1, 5.1); involvement during hospitalization, OR = 2.61 (CI = 1.3, 5.2); exposure to practice management, OR = 2.39 (CI = 1.5, 3.8); good balance of general pediatric patients, OR = 2.34 (CI = 1.5, 3.6); resident as patient advocate, OR = 1.74 (CI = 1.2, 2.4); and appropriate amount of nursing support, OR = 1.65 (CI = 1.1, 2.6). Future career choice, type of continuity site, and level of training were not found to be statistically significant., Conclusions: Pediatric resident satisfaction was significantly associated with 7 variables, the most important of which were the ability of the preceptor to serve as a role model and teacher. The type of continuity site was not significant. Residency programs may use these data to develop interventions to enhance resident satisfaction, which may lead to enhanced work performance and patient satisfaction.

Cerebrovascular disease is a common cause of morbidity in sickle cell anemia (HbSS): approximately 10% of patients have a clinical stroke before 20 years of age, and another 22% have silent infarction on magnetic resonance imaging. The phenotypic variation among patients with HbSS suggests a role for modifier genes and/or environmental influences. To assess the familial component of clinical stroke in HbSS, we estimated the prevalence of clinical stroke among all patients and among HbSS sibling pairs at 9 pediatric centers. The sample included 3425 patients with sickle cell disease who were younger than 21 years, including 2353 patients with HbSS. The stroke prevalence was 4.9% for all genotypes; 7.1% for patients with HbSS; 1.1% for patients with HbSbeta(o) thalassemia; 0.6% for patients with Sbeta(+) thalassemia; and 0% for patients with HbSC. In 207 sibships, more than 1 child had HbSS. There were 42 sibships in which at least 1 sibling had a stroke, and in 10 of the 42, 2 siblings had a stroke. A permutation test indicated that the number of families in which 2 children had strokes was larger than the number expected if strokes were randomly distributed among children in sibships (P =.0012). There was no difference in stroke prevalence based on sex, nor was the mean age at stroke presentation significantly different between singletons and sibships with stroke. We conclude that there is a familial predisposition to stroke in HbSS. Attempts to identify genetic modifiers should be initiated with family-based studies.

Conformational differences between type I antiestrogen-liganded estrogen receptor and estradiol (E2)-liganded estrogen receptor (ER) are thought to be responsible for differentiating agonist versus antagonist ER activity at individual genes. To examine the impact of ER ligand on estrogen-response element (ERE) binding kinetics and receptor conformation, we quantitated the effect of site-directed, ER-specific antibodies raised against synthetic peptides corresponding to the DNA-binding domain of human ER on ER-ERE binding in vitro. Although 4-hydroxytamoxifen-liganded-ER (4-OHT-ER) and E2-ER bind a consensus ERE with equal high affinity, the stoichiometry of 4-OHT-ER-ERE binding at saturation is approximately 50% lower than that of E2-ER binding to all ERE sequences tested. In contrast, the ERE binding stoichiometry of tamoxifen aziridine-liganded ER (TAz-ER) is identical to that of E2-ER: one receptor dimer bound per ERE. The difference in binding stoichiometry is caused by dissociation of one molecule of 4-OHT from the ER as the dimeric receptor binds DNA. Addition of low concentrations of ER-specific polyclonal antibodies AT3A or AT3B prevented 4-OHT ligand dissociation, yielding an increase in specific 4-OHT-ER-ERE binding to a level equal to that of E2-ER- or TAz-ER-ERE binding. However, higher amounts of AT3A or AT3B inhibited specific ERE binding of both 4-OHT- and E2-ER. We conclude that differences in ER conformation when liganded with 4-OHT versus E2 are revealed by these antibodies and that such differences in receptor conformation may influence subsequent interaction of the receptor with other proteins necessary for transactivation.

A luminol-dependent chemiluminescence (CL) microassay was developed to measure phagocytic function of peripheral blood leukocytes. Buffy coats, obtained by centrifugation of only 100 microliter of whole blood, provided an enriched population of polymorphonuclear leukocytes (PMNs). The total reaction mixture, consisting of leukocytes-luminol-inducer (opsonized zymosan), was 450 microliter. Peak CL activity was seen 5 min after addition of inducer at 37 degrees C with cells tested within 60 min after collection. Tests to determine precision and reproducibility of the microassay gave a coefficient of variation of 8.5% and 11%, respectively. There was no significant difference between the mean peak CL values for 20 healthy adult donors compared to 14 premature neonates, however, the newborns' CL activity declined more rapidly; CL activity was severely depressed in cells obtained from a patient with chronic granulomatous disease. Results suggest that this microassay provides a simple, rapid, and reliable test of phagocytic function in cases where the amount of blood available for testing is limited.

A second BamHI DNA polymorphism has been identified in the factor IX gene in an American black population at an allelic frequency of 0.13. This site has been localized within 500 basepairs (bp) 5' to the XmnI intron 3 polymorphic site and increases the heterozygosity of black females at the factor IX gene locus. In addition, haplotype analysis of factor IX genes at five polymorphic loci indicates that although there is conservation of sequences between the races, factor IX genes show more heterogeneity in an American black population and thus more heterozygosity is observed in black females compared with whites. This increased heterogeneity is due to DNA polymorphisms unique to black populations and to linkage equilibrium between the most 5' and 3' polymorphic sites in factor IX genes in blacks.

Hemophilia B is an X-linked recessive bleeding disorder resulting from a deficiency of the coagulation factor IX (FIX) protein activity, a vitamin K-dependent serine protease active in both the intrinsic and extrinsic coagulation systems. DNA analyses of the factor IX gene in two unrelated patients with severe hemophilia B, with a IX coagulant activity less than 1% and undetectable FIX antigen, detected the loss of the second TaqI site in exon h (VIII) in both individuals. Polymerase chain reaction (PCR) amplification of 576 base pairs of exon h (VIII) with cloning and dideoxy sequencing of cloned DNA from one hemophiliac revealed a single C----T transition in codon 338 that changes an arginine residue codon CGA to a nonsense codon TGA. Allele-specific oligonucleotide probe hybridization with a mutant (C----T) and a wild-type allele confirmed the same mutation in amplified genomic DNA of the second hemophilia patient. The C----T transition represents another example of mutation at a CpG dinucleotide. DNA polymorphism analysis of the FIX gene in both individuals revealed each to be on a separate FIX haplotype; therefore, predicting each to be a separate mutation event.