Surface Reconstruction of the Pediatric Larynx via Structure from Motion Photogrammetry: A Pilot Study

Endoscopy is the gold standard for characterizing pediatric airway disorders, however, it is limited for quantitative analysis due to lack of three-dimensional (3D) vision and poor stereotactic depth perception. We utilize structure from motion (SfM) photogrammetry, to reconstruct 3D surfaces of pathologic and healthy pediatric larynges from monocular two-dimensional (2D) endoscopy. Models of pediatric subglottic stenosis were 3D printed and airway endoscopies were simulated. 3D surfaces were successfully reconstructed from endoscopic videos of all models using an SfM analysis toolkit. Average subglottic surface error between SfM reconstructed surfaces and 3D printed models was 0.65 mm as measured by Modified Hausdorff Distance. Average volumetric similarity between SfM surfaces and printed models was 0.82 as measured by Jaccard Index. SfM can be used to accurately reconstruct 3D surface renderings of the larynx from 2D endoscopy video. This technique has immense potential for use in quantitative analysis of airway geometry and virtual surgical planning.

Multidisciplinary Advanced Surgical Planning for Slide Tracheoplasty Using 3D-Printed Models

OBJECTIVE

The objective of this study was to develop and assess multidisciplinary advanced surgical planning (ASP) sessions using three dimensional (3D) printed models for cervicothoracic slide tracheoplasty (CST). We hypothesized that these sessions would improve surgeon confidence, streamline intraoperative planning, and highlight the utility of 3D modeling.

METHODS

3D-printed patient-specific trachea models were used in pre-operative ASP sessions consisting of a multidisciplinary case discussion and hands-on slide tracheoplasty simulation. Participants completed a survey rating realism, utility, impact on the final surgical plan, and pre- and post-session confidence. Statistical analysis was performed via Wilcoxon and Kruskal-Wallis tests.

RESULTS

Forty-eight surveys were collected across nine sessions and 27 different physicians. On a 5-point Likert scale, models were rated as "very realistic", "very useful" (both median of 4, IQR 3-4 and 4-5, respectively). Overall confidence increased by 1.4 points (+/- 0.7, p < 0.0001), with the largest change seen in those with minimal prior slide tracheoplasty experience (p = 0.005). Participants felt that the sessions "strongly" impacted their surgical plan or anticipated performance (median 4, IQR 4-5), regardless of training level or experience.

CONCLUSION

3D-printed patient-specific models were successfully implemented in ASP sessions for CST. Models were deemed very realistic and very useful by surgeons across multiple specialties and training levels. Surgical planning sessions also strongly impacted the final surgical plan and increased surgeon confidence for CST.

LEVEL OF EVIDENCE

IV Laryngoscope, 2024.

Virtually Assisted Personalized Tracheostomy Tube Design in Pediatric Complex Airway Anomalies

We sought to assess the feasibility of virtually assisted personalized tracheostomy tube (vapTT) implementation for patients with congenital airway anomalies (CAAs) and persistent tracheostomy tube (TT)-related respiratory failure at a tertiary pediatric hospital. Three patients (0-18 years) with CAAs and recurrent TT-related respiratory complications were managed with vapTT over 5 years. Patients underwent airway computed tomography acquisition with 3-dimensional reconstruction and TT virtual modeling for shape customization. Models were transferred to Bivona for fabrication based on industry-standard materials and processes. Clinical information and tracheoscopies assessing position, obstruction, and granulation were reviewed. Patients demonstrated resolution of visualized TT-related obstruction, granulation, or ulceration and de-escalation of respiratory support. Clinical events requiring urgent tracheoscopy decreased in all 3 patients. Sufficient relief of critical airway obstruction allowed progression of medical care and/or discharge. VapTTs are feasible for patients with CAA. This new frontier in personalized devices may serve uniquely challenging patient populations for whom standard treatments have failed.

A Validated 3D Printed Laryngeal Suturing Simulator for Endoscopic Laryngeal Cleft Repair

OBJECTIVES

Endoscopic laryngeal cleft repair (ELCR) with endolaryngeal suturing is an advanced surgical skill. This study objective was to assess the validity of 3-dimensionally (3D) printed laryngeal suturing simulator for ELCR.

STUDY DESIGN

Development and validation of a simulator for ELCR.

METHODS

An ELCR model was developed using 3D printed and readily available materials. Participants were surveyed before and after a simulation session using five-point Likert scale questions. Performance data was assessed using blinded expert video review and rated using a novel objective structured assessment of technical skills (OSATS) for endoscopic laryngeal suturing.

RESULTS

Twenty-one participants ranging from residents to attendings completed the simulation session. Survey respondents reported on a five-point Likert scale that the model was "easy to use" and "quite realistic" (both mean of 4). Confidence improved significantly in 86% of participants (p < 0.01). Overall OSATS scores (out of a total of 55) showed a median improvement in technical skills of 11.7 points (p = 0.004). OSATS demonstrated good intra-rater (κ = 0.689 and 0.677) and moderate inter-rater (κ = 0.573) reliability. Completion times improved from the first to the last suture by a median time of 512 to 350 s (decrease of 202 s, p = 0.002). Participants with no prior ELCR experience improved more than those with in vivo experience.

CONCLUSION

This study demonstrates the validity of a simulator utilizing 3D printed larynges for ELCR. A novel OSATS for endoscopic laryngeal suturing was successfully implemented. Confidence, technical skills, and completion times improved with the use of the model across a variety of participants. Laryngoscope, 133:785-791, 2023.

Validation of the Seattle Suprastomal Safety Score (5S): A Novel Measure in Pediatric Tracheostomy-Dependent Patients

OBJECTIVE

Suprastomal collapse and granulation are common sequelae of pediatric tracheostomy. We present the first measure of suprastomal obstructive pathology, the Seattle Suprastomal Safety Score (5S), an instrument with 2 domains: collapse and granulation.

STUDY DESIGN

Cross-sectional repeated testing survey.

SETTING

Electronic survey.

METHODS

A library of images was assembled from still pictures of the suprastomal area in 50 patients who previously underwent trachea-bronchoscopy at a quaternary children's hospital. Five pediatric otolaryngologists and 2 pediatric pulmonologists reviewed the images in random, blinded fashion and provided 5S scores. Participants repeated this process 2 to 4 weeks later. Interrater agreement was calculated with an intraclass correlation coefficient (ICC) with a 2-way random-effects model and Fleiss's κ. Intrarater agreement was measured with an ICC using a 2-way mixed-effects model as well as with test-retest correlations using Spearman rank coefficient. All measures were performed separately on collapse and granulation domains.

RESULTS

ICC for interrater agreement was 0.88 (95% CI, 0.82-0.93) for collapse and 0.97 (95% CI, 0.96-0.98) for granulation, indicating almost perfect agreement. Fleiss's κ demonstrated moderate agreement for collapse and almost perfect agreement for granulation. ICC for intrarater agreement was 0.95 (95% CI, 0.93-0.97) and 0.99 (95% CI, 0.98-0.99) for collapse and granulation, respectively, indicating almost perfect agreement. Spearman rank correlation for test-retest demonstrated substantial agreement for collapse and almost perfect agreement for granulation.

CONCLUSION

The 5S demonstrates excellent interrater and intrarater agreement, making it highly reliable as a novel measure of suprastomal collapse and granulation in tracheostomy-dependent pediatric patients.

Drug-induced sleep endoscopy directed surgery improves polysomnography measures in overweight and obese children with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea affects approximately 1-4% of all children, with increased prevalence amongst overweight and obese children.

OBJECTIVE

To assess the effects of drug-induced sleep endoscopy (DISE)-directed surgery on polysomnography parameters in obese and overweight children.

MATERIAL/METHODS

A retrospective case-series was performed on obese and overweight pediatric patients who underwent clinically indicated DISE-directed surgery. Forty children met the inclusion criteria, including: body mass index ≥85%, DISE-study, and pre- and post-DISE polysomnography. Patients were divided into surgically naïve (n = 23) and prior adenotonsillectomy (n = 17) groups. Demographic and clinical characteristics were examined with chi-square and Wilcoxon rank-sum test. Polysomnography parameters were compared with Wilcoxon signed rank test.

RESULTS

Of 40 children with mean BMI 94% and mean age 8 ± 6 years old, 17 (43%) underwent a previous adenotonsillectomy. Overall, significant improvements were observed in the apnea-hypopnea index (AHI; 25.0 to 9.9 events/hour, p < .01) and oxygen nadir (82.7% to 88.5%, p < .01). A similar pattern was observed among the surgically naïve (AHI: 35.9 to 12.7 events/hour, p = .04; oxygen nadir: 79.7% to 86.4%, p = .2) and post-adenotonsillectomy groups (AHI: 10.4 to 6.2 events/hour, p = .02; oxygen nadir: 86.7% to 91.2%, p < .01).

CONCLUSIONS/SIGNIFICANCE

Polysomnography parameters significantly improved following DISE-directed interventions in obese and overweight children with obstructive sleep apnea.

Competency-Based Assessment Tool for Pediatric Esophagoscopy: International Modified Delphi Consensus

OBJECTIVES/HYPOTHESIS

Create a competency-based assessment tool for pediatric esophagoscopy with foreign body removal.

STUDY DESIGN

Blinded modified Delphi consensus process.

SETTING

Tertiary care center.

METHODS

A list of 25 potential items was sent via the Research Electronic Data Capture database to 66 expert surgeons who perform pediatric esophagoscopy. In the first round, items were rated as "keep" or "remove" and comments were incorporated. In the second round, experts rated the importance of each item on a seven-point Likert scale. Consensus was determined with a goal of 7 to 25 final items.

RESULTS

The response rate was 38/64 (59.4%) in the first round and returned questionnaires were 100% complete. Experts wanted to "keep" all items and 172 comments were incorporated. Twenty-four task-specific and 7 previously-validated global rating items were distributed in the second round, and the response rate was 53/64 (82.8%) with questionnaires returned 97.5% complete. Of the task-specific items, 9 reached consensus, 7 were near consensus, and 8 did not achieve consensus. For global rating items that were previously validated, 6 reached consensus and 1 was near consensus.

CONCLUSIONS

It is possible to reach consensus about the important steps involved in rigid esophagoscopy with foreign body removal using a modified Delphi consensus technique. These items can now be considered when evaluating trainees during this procedure. This tool may allow trainees to focus on important steps of the procedure and help training programs standardize how trainees are evaluated.

LEVEL OF EVIDENCE

5. Laryngoscope, 131:1168-1174, 2021.

Pediatric Otolaryngology Divisional and Institutional Preparatory Response at Seattle Children's Hospital after COVID-19 Regional Exposure

Coronavirus disease 2019 (COVID-19) is a novel coronavirus resulting in high mortality in the adult population but low mortality in the pediatric population. The role children and adolescents play in COVID-19 transmission is unclear, and it is possible that healthy pediatric patients serve as a reservoir for the virus. This article serves as a summary of a single pediatric institution's response to COVID-19 with the goal of protecting both patients and health care providers while providing ongoing care to critically ill patients who require urgent interventions. A significant limitation of this commentary is that it reflects a single institution's joint effort at a moment in time but does not take into consideration future circumstances that could change practice patterns. We still hope dissemination of our overall response at this moment, approximately 8 weeks after our region's first adult case, may benefit other pediatric institutions preparing for COVID-19.

The Trach Safe Initiative: A Quality Improvement Initiative to Reduce Mortality among Pediatric Tracheostomy Patients

OBJECTIVE

To describe the Trach Safe Initiative and assess its impact on unanticipated tracheostomy-related mortality in outpatient tracheostomy-dependent children (TDC).

METHODS

An interdisciplinary team including parents and providers designed the initiative with quality improvement methods. Three practice changes were prioritized: (1) surveillance airway endoscopy prior to hospital discharge from tracheostomy placement, (2) education for community-based nurses on TDC-focused emergency airway management, and (3) routine assessment of airway events for TDC in clinic. The primary outcome was annual unanticipated mortality after hospital discharge from tracheostomy placement before and after the initiative.

RESULTS

In the 5 years before and after the initiative, 131 children and 155 children underwent tracheostomy placement, respectively. At the end of the study period, the institution sustained Trach Safe practices: (1) surveillance bronchoscopies increased from 104 to 429 bronchoscopies, (2) the course trained 209 community-based nurses, and (3) the survey was used in 488 home ventilator clinic visits to identify near-miss airway events. Prior to the initiative, 9 deaths were unanticipated. After Trach Safe implementation, 1 death was unanticipated. Control chart analysis demonstrates significant special-cause variation in reduced unanticipated mortality.

DISCUSSION

We describe a system shift in reduced unanticipated mortality for TDC through 3 major practice changes of the Trach Safe Initiative.

IMPLICATION FOR PRACTICE

Death in a child with a tracheostomy tube at home may represent modifiable tracheostomy-related airway events. Using Trach Safe practices, we address multiple facets to improve safety of TDC out of the hospital.

Surveillance endoscopy after tracheostomy placement in children: Findings and interventions

OBJECTIVES/HYPOTHESIS

The Seattle Children's Hospital implemented the Trach Safe Initiative to improve airway safety in tracheostomy-dependent children (TDC). A key tenet of this initiative is surveillance endoscopy. The objectives of this study were to describe the prevalence of abnormal airway changes in TDC, identify risk factors for these changes, and describe the frequency of airway interventions.

STUDY DESIGN

Retrospective case series.

METHODS

This is a review of children 0 to 21 years old who underwent tracheostomy and surveillance endoscopy from February 1, 2014 to January 1, 2019. Descriptive statistics were used to report the prevalence of abnormal airway changes and interventions following tracheostomy. Pearson χ² tests and logistic regression were used to identify risk factors for the development of abnormal changes.

RESULTS

There were 127 children identified. The median time from tracheostomy to initial surveillance endoscopy was 1.6 months (interquartile range = 1.3-2.4 months). At initial endoscopy, 86.6% of patients had at least one abnormal airway finding. The most common findings were subglottic edema/stenosis (57.3%), glottic edema (37.3%), and suprastomal granulation tissue (31.8%). Prematurity and a history of failed extubations were significantly associated with abnormal findings on endoscopy (odds ratio [OR] = 7.2, P = .01 and OR = 4.1, P = .03, respectively). Of those with abnormal findings, 32.7% underwent an intervention to improve airway patency and safety. The most common interventions performed were suprastomal granuloma excision (44.4%), steroid injection (22.2%), and balloon dilation of the glottis or subglottis (19.4%).

CONCLUSIONS

The prevalence of early abnormal airway changes in TDC is high, particularly in young children with a history of prematurity and failed extubation.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1327-1332, 2020.

Short-term swallowing outcomes following type 1 laryngeal cleft injection

INTRODUCTION

Interarytenoid injection augmentation at the time of initial diagnostic endoscopy for aspiration and dysphagia may result in near-immediate improvement in swallowing function, potentially obviating the need for future formal endoscopic repair of type 1 laryngeal cleft. Interarytenoid injection augmentation may also address physiologic aspiration. Early treatment of type 1 laryngeal cleft may allow for expedited liberalization of feedings. The objective of this study was to evaluate the effect of interarytenoid injection augmentation (IIA) for type 1 laryngeal clefts (LC-1) on short-term swallowing function assessed by videofluoroscopic swallowing study (VFSS).

METHODS

This was a retrospective cohort study of patients age ≤24 months with dysphagia on preoperative VFSS who underwent IIA with calcium hydroxyapatite for LC-1 during direct laryngoscopy and bronchoscopy from June to October 2017 at a tertiary care academic subspecialty hospital. Exclusion criteria included prior endoscopic or open LC repair (n = 1), gastrostomy tube dependence (n = 1), additional procedures at the time of IIA (supraglottoplasty, frenulectomy, n = 1). Children without postoperative VFSS within 30 days of injection were excluded (n = 2). Fifteen children met inclusion criteria for analysis. The primary endpoint was improvement in safely swallowed consistency as defined by recommendation to liberalize diet by at least a half-consistency (e.g. half-honey to nectar thick liquid). Secondary endpoints included clinical assessment of dysphagia and postoperative respiratory events.

RESULTS

Median [range] age at injection was 15.2 [7.7-24.3] months and 67% of patients were female (n = 10). The majority (13/15) of patients were full-term and 80% of patients (n = 12) had documented gastroesophageal reflux disease (GERD). Median time from injection to VFSS was 16 [9-29] days. Improvement in safely swallowed consistency was noted in 60% (n = 9) of patients. Aspiration completely resolved in two patients. Swallow function was unchanged in 40% of patients (n = 6); no patients experienced worsening dysphagia. No respiratory complications were documented during inpatient observation.

CONCLUSION

IIA is a safe procedure that may result in immediate improvement in dysphagia in select patients with LC-1. IIA does not address neurologic, developmental, or other anatomic etiologies of dysphagia. Additional studies are required to determine long-term efficacy of IIA on dysphagia and pulmonary complications, as well as the patient- and caregiver-related outcome measures.

Face, content, and construct validation of a low-cost, non-biologic, sinus surgery task trainer and knowledge-based curriculum

BACKGROUND

The purpose of this study was to evaluate face and content validity of a low-cost, low-technology, non-biologic endoscopic sinus surgery (ESS) task trainer and knowledge-based curriculum followed by construct validation of the task trainer.

METHODS

A sinus surgery task trainer and curriculum were developed. Attending otolaryngologists were surveyed regarding the utility of the task trainer and curriculum. A cross-sectional construct validation study was performed including medical students, residents, and attending otolaryngologists. Nine tasks were performed on the task trainer and graded using a global rating scale (GRS). Predictors of task trainer performance were evaluated, and spatial performance was measured. Regression analyses were performed to assess main associations.

RESULTS

All attending physicians (n = 7) agreed that the task trainer accelerates the learning curve and incorporates essential ESS techniques and that the knowledge-based curriculum describes anatomical and technical knowledge germane to ESS. Twelve medical students, 9 otolaryngology residents, and 5 attending otolaryngologists completed task trainer testing. GRS score varied by level of training after adjusting for potential confounders (slope = 2.63; p = 0.001). There was evidence of an association between a history of video gaming (slope = 1.33; p = 0.077), sports experience (slope = 2.08; p = 0.033), and sinus surgery simulation (slope = 2.72; p = 0.023) with GRS score, although not statistically significant.

CONCLUSION

This study demonstrated validity of a knowledge-based sinus surgery curriculum and low-cost, sinus task trainer supporting use in early training. Participants with prior video gaming, sports participation, and sinus surgery simulation experience perform better at baseline on the task trainer.

Can Simulation and Human Factors Improve Systems and Safety?

Program Description:

Our expertise and skill are essential, but not sufficient, for optimal patient outcomes. We work with teams and we work within systems with variable functionality. How can we make sure our team works together effectively? How can we improve the systems within which we work? An expert panel will describe how we can use simulation and the science of human factors to improve the processes, the equipment, and even the spaces in which we work. Examples address emergency response teams, airway carts, and electronic health records. Our keynote speaker, F. Jacob Seagull, PhD, is an expert in human factors applications in health care.

Educational Objectives:

(1) Understand how simulation can be used to improve health care delivery systems and safety. (2) Understand how human factors principles can be applied to improve health care delivery systems and safety.

What big size you have! Using effect sizes to determine the impact of public health nursing interventions

BACKGROUND

The Omaha System is a standardized interface terminology that is used extensively by public health nurses in community settings to document interventions and client outcomes. Researchers using Omaha System data to analyze the effectiveness of interventions have typically calculated p-values to determine whether significant client changes occurred between admission and discharge. However, p-values are highly dependent on sample size, making it difficult to distinguish statistically significant changes from clinically meaningful changes. Effect sizes can help identify practical differences but have not yet been applied to Omaha System data.

METHODS

We compared p-values and effect sizes (Cohen's d) for mean differences between admission and discharge for 13 client problems documented in the electronic health records of 1,016 young low-income parents. Client problems were documented anywhere from 6 (Health Care Supervision) to 906 (Caretaking/parenting) times.

RESULTS

On a scale from 1 to 5, the mean change needed to yield a large effect size (Cohen's d ≥ 0.80) was approximately 0.60 (range = 0.50 - 1.03) regardless of p-value or sample size (i.e., the number of times a client problem was documented in the electronic health record).

CONCLUSIONS

Researchers using the Omaha System should report effect sizes to help readers determine which differences are practical and meaningful. Such disclosures will allow for increased recognition of effective interventions.

Efficacy of Surgical Simulators for Otolaryngology Training

Program Description:

Recently, there has been growing interest in developing and using simulation technologies for basic surgical skills training for residents. In addition, as our specialty continually evolves and we make efforts for quality and lifelong learning, simulation technologies may also be useful for keeping experienced surgeons up-to-date with their skills. We will present currently available surgical simulators for temporal bone dissection, endoscopic sinus surgery, airway endoscopy, and tonsillectomy. The presenters will provide descriptions and show videos demonstrating the function of these devices. In addition, each panelist will present data evaluating the efficacy of these simulators as being effective teaching instruments.

Educational Objectives:

1) Differentiate the variety of simulation technology devices available for surgical skills training in otolaryngology–head neck surgery. 2) Recognize the advantages and limitations of using simulation technologies for acquiring and maintaining surgical skills. 3) Assess the validity of the studies presented to evaluate the efficacy of simulation devices as valuable learning tools.

A Novel Low Cost Task Trainer for Tonsillectomy Simulation

Objective: 1) Develop a novel low cost task trainer which appropriately simulates the basic steps involved in a tonsillectomy procedure for the novice trainee. 2) Assess this task trainer for feasibility, face validity, usability, and content validity using a group of expert observers.

Method: The task trainer was developed to reproduce all steps of the tonsillectomy procedure using pieces of steak with adherent connective tissue to simulate the tonsil for electrocautery dissection. Pediatric otolaryngology attendings and fellows were surveyed using a 5-point Likert scale to assess ease of use, realism, and perceived utility.

Results: The model consists of a Styrofoam head with cut-out oropharynx and steak pieces suspended by metal clips and wired to an electrocautery unit. Surgeons use a headlight, grasp the muscle, and electro-dissect it away from the fat. Cost of the model was twenty US dollars. Ten attending pediatric otolaryngologists and 4 pediatric otolaryngology fellows completed simulated tonsillectomies and surveys. Participants rated a median realism score of 4 out of 5 (very realistic) and ease of use a median 5 out of 5 (simple and intuitive). All participants agreed residents would be better prepared for real tonsillectomies after using the model.

Conclusion: Production and use of a tonsillectomy task trainer is a feasible and inexpensive endeavor for training programs and may provide appropriate usability and fidelity in simulating tonsillectomy for trainees. Face and content validity were confirmed by expert observers. Further study will assess validity and effectiveness for teaching and assessment.

Pediatric Epiglottitis: Predictors of Conservative Treatment

Objective: 1) To evaluate predictors of conservative management in pediatric patients with epiglottitis. 2) To use national trends, variances, and outcomes to better understand current management trends of this rare though highly morbid disease.

Method: The Kids’ Inpatient Databases (2006 and 2009) were searched using ICD-9 CM codes for acute epiglottitis with (464.30) and without (464.31) obstruction. Demographics and hospital characteristics of pediatric patients who required airway intervention (defined as intubation or tracheotomy) were compared with those who were managed conservatively without airway intervention.

Results: A total of 820 patients were included in the analysis, and 115 (14%) required intervention and 86% were managed conservatively. Mortality was less than 10 patients. There were no significant differences between groups with respect to age, gender, or race. Characteristics predictive of conservative management include urgent admission type (vs emergent, P = .015), urban nonteaching hospital (vs urban teaching, P = .002), nonchildren’s hospital (vs children’s unit or children’s hospital, P < .0001) and small/medium-sized hospital (vs large, P = .03). Length of hospital stay was shorter (mean 3.65 days vs 10.87 days, P = .01) and cost was lower in patients who were managed conservatively (mean $18,487 vs $83,037, P < .0001).

Conclusion: The majority of pediatric epiglottitis patients are currently managed without intubation or tracheotomy with low mortality. Conservatively managed admissions are more likely for nonemergent presentations at nonpediatric, nonteaching, small/medium-sized hospitals, and are lower in cost. Additional studies are needed to further characterize patients which would be appropriate for conservative management.

PCR offers no advantage over culture for microbiologic diagnosis in cellulitis

PURPOSE

Most cases of cellulitis are traditionally attributed to β-hemolytic Streptococcus and Staphylococcus species, although in most cases, no organism is identified. Development of PCR using the conserved bacterial 16 S rRNA DNA permits identification of bacteria independent of conventional culture approaches and prior use of antibiotics.

METHODS

We used PCR-based techniques to identify cellulitis etiology using aspirate samples from affected skin. Saline was infiltrated and aspirated at the site of greatest erythema or at the cellulitic border. Samples were tested for 16 S rRNA DNA, and organism-specific probes used to identify bacteria commonly seen in skin infections.

RESULTS

Aspirates from 32 patients were studied, and 16 S rRNA DNA was detected in nine of these patient samples (28.1%). Bacterial species were identified by PCR methods in six of these nine samples (66.6%), with S. aureus and methicillin-resistant S. aureus (MRSA) identified in four and two, respectively, of these samples. Of the patients with positive aspirate bacterial cultures (3/9, 33.3%), S. aureus and coagulase-negative Staphylococcus (CoNS) were present on cultures of two of the three (both 66.6%) positive samples. Only in one of the three positive bacterial cultures did the PCR method detect the same organism as was detected by culture. Among patients with positive provider-collected clinical cultures, MRSA was the predominant organism (11/18, 61.1%) and when present, it was found as the sole organism. Where S. aureus or Streptococcus species were detected by molecular methods, clinical cultures yielded a positive result as well.

CONCLUSIONS

PCR-based techniques do not appear to be more sensitive than aspirate cultures for the detection of pathogens in cellulitis.

Airway System of Care Assessment with High Fidelity Simulation

Objective: 1) Determine the capacity of high-fidelity simulation in critical airway obstruction to assess the existing system of care at a pediatric institution. 2) Inform the development of a protocol for the multidisciplinary management of critical airway obstruction in the emergency department (ED) and the operating room (OR).

Method: Design was a prospective assessment, using simulation, of critical airway obstruction management at a pediatric referral center. Subjects were ED, OR, and otolaryngology (ENT) providers. We developed a novel simulation scenario of foreign body aspiration. Measures assessed included ED airway maneuvers, time to ENT arrival, and subject survey responses.

Results: Over 3 months, 67 providers participated in 6 simulations (3 complete in ED and 3 partial obstructions from ED to OR). The mean rating of simulation realism was 6.3 out of 7 (range, 4-7). Twenty-one of 67 (31%) providers stated they would apply something learned in the simulation to a real case. In 2 simulations, laryngoscopy was inappropriately performed and resulted in patient deterioration. In all simulations there was confusion about subspecialty consultation. ENT was consulted in all cases; the median time to ENT arrival was 6.8 minutes (range, 5.7-9 minutes). Identified system deficiencies included a lack of ENT equipment in the ED.

Conclusion: High-fidelity medical simulation is a safe, feasible, and effective method to assess current systems of care in high acuity, low frequency events. We will use the findings from these simulations to develop, implement, and reassess a protocol for the multidisciplinary management of pediatric critical airway obstruction at our institution.

Mantle oxidation state and its relationship to tectonic environment and fluid speciation

The earth's mantle is degassed along mid-ocean ridges, while rehydration and possibly recarbonaton occurs at subduction zones. These processes and the speciation of C-H-O fluids in the mantle are related to the oxidation state of mantle peridotite. Peridotite xenoliths from continental localities exhibit an oxygen fugacity (fo(2)) range from -1.5 to +1.5 log units relative to the FMQ (fayalite-magnetite-quartz) buffer. The lowest values are from zones of continental extension. Highly oxidized xenoliths (fo(2) greater than FMQ) come from regions of recent or acive subduction (for example, Ichinomegata, Japan), are commonly amphibole-bearing, and show trace element and isotopic evidence of fluid-rock interaction. Peridotites from ocean ridges are reduced and have an averae fo(2) of about -0.9 log units relative to FMQ, virtually coincident with values obtained from mid-ocean ridge basalt (MORB) glasses. These data are further evidence of the genetic link between MORB liquids and residual peridotite and indicate that the asthenosphere, although reducing, has CO(2) and H(2)O as its major fluid species. Incorporation of oxidized material from subduction zones into the continental lithosphere produces xenoliths that have both asthenospheric and subduction signatures. Fluids in the lithosphere are also dominated by CO(2) and H(2)O, and native C is generally unstable. Although the occurrence of native C (diamond) in deep-seated garnetiferous xenoliths and kimberlites does not require reducing conditions, calculations indicate that high Fe(3+) contents are stabilized in the garnet structure and that fo(2) deareases with increasing depth.

H1N1 influenza A presenting as bacterial tracheitis

Six cases of bacterial tracheitis (BT) occurring early in the 2009 flu season have been isolated in conjunction with the H1N1 strain of influenza A (H1N1). No previous H1N1 cases have presented as BT in the literature to date. We would like to discuss viral coinfection in BT patients and how this new strain may affect the rate and type of presentation encountered. The life-threatening potential of BT and the pandemic proportion of H1N1 highlight a possibly dangerous combination that should be recognized by the otolaryngology community. In hospitalized patients with presumed BT, consideration should be given to routine H1N1 testing and the addition of antiviral medication when indicated as this entity is further investigated.

Endurance and strength training outcomes on cognitively impaired and cognitively intact older adults: a meta-analysis

BACKGROUND

Dementia is a common syndrome in the geriatric population. Subsequent impairment of cognitive functioning impacts the patient's mobility, ADLs, and IADLs. It is suggested that older persons with lower levels of cognition are less likely to achieve independence in ADLs and ambulation (1-2). Frequently, nursing home residents are viewed as too frail or cognitively impaired to benefit from exercise rehabilitation. Often, persons with Mini Mental State Score (MMSE) score below 25 are excluded from physical rehabilitation programs. However, Diamond (3) and Goldstein (4) concluded that geriatric patients with mild to moderate cognitive impairment were just as likely as cognitively intact patients to improve in functional abilities as a result of participation in exercise rehabilitation programs.

PURPOSE

The objective of this study is to compare, through a meta-analysis endurance and strength outcomes of Cognitively Impaired (MMSE < 23) and Cognitively Intact (MMSE superior 24) older adults who participate in similar exercise programs.

METHODS

Published articles were identified by using electronic and manual searches. Key search words included exercise, training, strength, endurance, rehabilitation, cognitive impairment, cognition, MMSE, older adult, aged, and geriatrics. Articles were included if the were from RCTs or well-designed control studies.

RESULTS

A total of 41 manuscripts met the inclusion criteria. We examined 21 exercise trials with cognitively impaired individuals (CI=1411) and 20 exercise trials with cognitively intact individuals (IN=1510). Degree of cognitive impairment is based on the reported MMSE score. Moderate to large effect sizes (ES = dwi, Hedges gi) were found for strength and endurance outcomes for the CI groups (dwi = .51, 95% CI= .42- .60), and for the IN groups (dwi = .49, 95% CI= .40- .58). No statistically significant difference in ES was found between the CI and IN studies on strength (t=1.675, DF= 8, P= .132), endurance (t=1.904, DF= 14, P=.078), and combined strength and endurance effects (t=1.434, DF= 56, P= .263).

CONCLUSIONS

These results suggest that cognitively impaired older adults who participate in exercise rehabilitation programs have similar strength and endurance training outcomes as age and gender matched cognitively intact older participants and therefore impaired individuals should not be excluded from exercise rehabilitation programs.

The North-West Diabetes Foot Care Study: incidence of, and risk factors for, new diabetic foot ulceration in a community-based patient cohort

AIMS

To determine the incidence of, and clinically relevant risk factors for, new foot ulceration in a large cohort of diabetic patients in the community healthcare setting.

METHODS

Diabetic patients (n = 9710) underwent foot screening in six districts of North-west England in various healthcare settings. All were assessed at baseline for demographic information, medical and social history, neuropathy symptom score, neuropathy disability score, cutaneous pressure perception (insensitivity to the 10 g monofilament), foot deformities, and peripheral pulses. Two years later, patients were followed up via postal questionnaire to determine the incidence of new foot ulcers. Cox's proportional hazards regression analysis was used to determine the independent, relative risk of baseline variables for new foot ulceration.

RESULTS

New foot ulcers occurred in 291/6613 patients who completed and returned their 2-year follow-up questionnaire (2.2% average annual incidence). The following factors were independently related to new foot ulcer risk: ulcer present at baseline (relative risk (95% confidence interval)) 5.32 (3.71-7.64), past history of ulcer 3.05 (2.16-4.31), abnormal neuropathy disability score (> or = 6/10) 2.32 (1.61-3.35), any previous podiatry attendance 2.19 (1.50-3.20), insensitivity to the 10 g monofilament 1.80 (1.36-2.39), reduced pulses 1.80 (1.40-2.32), foot deformities 1.57 (1.22-2.02), abnormal ankle reflexes 1.55 (1.01-2.36) and age 0.99 (0.98-1.00).

CONCLUSIONS

More than 2% of community-based diabetic patients develop new foot ulcers each year. The neuropathy disability score, 10 g monofilament and palpation of foot pulses are recommended as screening tools in general practice.

Comparison of pregnancy outcome in mares among methods used to evaluate and select spermatozoa for insemination

An artificial insemination dose for mares consisting of 500 million progressively motile spermatozoa is considered "standard" by most clinicians. However, little information is available directly comparing pregnancy outcome among methods of evaluating and selecting spermatozoa for insemination. The objective of this study was to determine if the method of spermatozoal evaluation and selection influences fertility as measured by pregnancy outcome. Mares were inseminated with 100 or 500 million spermatozoa that were selected for progressive motility, normal morphology, hypoosmotic swelling or absolute number regardless for evaluation method or quality. Thirty-two breeding cycles were tested for each treatment group and at each spermatozoal dose. Pregnancy outcomes were 44 and 41%, 55 and 41%, 39 and 31%, and 45 and 41%, for the 100 and 500 million progressively motile, morphologically normal, hypoosmotic swelling positive and absolute number treatment groups, respectively. Pregnancy outcome did not differ among methods of spermatozoal evaluation and selection for artificial insemination in the 100 (P=0.52) or 500 (P=0.78) million spermatozoa groups. Also the total number of spermatozoa and the absolute number of progressively motile, morphologically normal or hypoosmotic swelling positive spermatozoa inseminated, were not closely associated with pregnancy outcome in the 100 (P=0.24, 0.29, 0.33 and 0.38, respectively) or 500 (P=0.20, 0.84, 0.50 and 0.74, respectively) million spermatozoa groups. In this study, we found that the method of spermatozoal evaluation did not offer an advantage for pregnancy when used to select spermatozoa for insemination at the doses tested. These results were surprising, as we expected there would be differences among the evaluation methods. Instead, we found that evaluating spermatozoa offered no advantage for pregnancy over simply inseminating with a specified number of spermatozoa not selected for any particular characteristic under the conditions of our experiment.

Impact of varying levels of expertise on decisions of category typicality

Experts on domains of basic level object categories possess extensive knowledge of features used to both individuate and categorize groups of similar members. Two studies were conducted to determine the impact of high knowledge on intermediate and advanced experts' typicality decisions for basic and subordinate level category exemplars, and to investigate whether the pattern of influence of factors (in particular, central tendency and subjective familiarity) remained fixed throughout the continuum of expertise. Example goodness increased as a function of the level of specificity of the category for which typicality was rated. Subjective familiarity was the principal determinant of typicality for individuals with high knowledge, whereas central tendency was related to typicality when knowledge was not particularly high. Advanced and intermediate experts produced similar ratings of typicality, indicating that individuals' decisions of typicality do not change markedly once intermediate levels of competency have been attained. The incorporation of knowledge effects into models of semantic memory, as well as interactions among knowledge, psychological factors, and environmental factors in determining typicality, are discussed.

An active site tyrosine influences the ability of the dimethyl sulfoxide reductase family of molybdopterin enzymes to reduce S-oxides

Dimethyl sulfoxide reductase (DMSOR), trimethylamine-N-oxide reductase (TMAOR), and biotin sulfoxide reductase (BSOR) are members of a class of bacterial oxotransferases that contain the bis(molybdopterin guanine dinucleotide)molybdenum cofactor. The presence of a Tyr residue in the active site of DMSOR and BSOR that is missing in TMAOR has been implicated in the inability of TMAOR, unlike DMSOR and BSOR, to utilize S-oxides. To test this hypothesis, Escherichia coli TMAOR was cloned and expressed at high levels, and site-directed mutagenesis was utilized to generate the Tyr-114 --> Ala and Phe variants of Rhodobacter sphaeroides DMSOR and insert a Tyr residue into the equivalent position in TMAOR. Although all of the mutants turn over in a manner similar to their respective wild-type enzymes, mutation of Tyr-114 in DMSOR results in a decreased specificity for S-oxides and an increased specificity for trimethylamine-N-oxide (Me(3)NO), with a greater change observed for DMSOR-Y114A. Insertion of a Tyr into TMAOR results in a decreased preference for Me(3)NO relative to dimethyl sulfoxide. Kinetic analysis and UV-visible absorption spectra indicate that the ability of DMSOR to be reduced by dimethyl sulfide is lost upon mutation of Tyr-114 and that TMAOR does not exhibit this activity even in the Tyr insertion mutant.

Using immunohistochemistry to study plant metabolism: the examples of its use in the localization of amino acids in plant tissues, and of phosphoenolpyruvate carboxykinase and its possible role in pH regulation

To understand many aspects of the metabolism of complex plant structures such as leaves, fruit and roots it is important to understand how metabolic processes are compartmentalized between tissues. The aim of this article is to show how immunohistochemistry, in conjunction with biochemical and physiological studies, is useful in understanding both the function of an enzyme in a tissue and metabolic processes occurring in plant tissues. This is illustrated by two examples. Firstly, the use of immunohistochemisty in the localization of amino acids in plant tissues is described. Secondly, the use of immunohistochemistry in understanding the function of an enzyme in a tissue and the metabolic processes occurring within the tissue is described. To illustrate this the example of phosophoenolpyruvate carboxykinase (PEPCK), an enzyme which is present in many plant tissues in which its function is unknown, is used. Evidence is provided that PEPCK may play a role in pH regulation in tissues active in the metabolism of nitrogen.

The effect of an interactive experience on music majors' perceptions of music for deaf students

The purpose of this study was to examine the effect of an interactive experience on music majors' perceptions of music experiences for deaf students. Twenty-three members of a pre-existing college brass ensemble served as subjects, and a 1-hour interactive concert/presentation for 10 deaf elementary children served as the independent variable. The interactive experience was designed to provide social, musical, and educational interactions between the college musicians and the deaf children. A pretest-posttest design was utilized, and the dependent variable was a questionnaire designed to examine the subjects' perceptions regarding music for deaf students, including how prepared, comfortable, and willing they felt to provide music experiences for deaf students. Results reveal that this single interactive experience had a significant effect on the subjects' perceptions of the value of music in the education of deaf children (p <.05). Although the pretest and posttest scores indicate that the subjects felt apprehensive about their preparedness to work with deaf students, the subjects felt significantly more positive about their preparedness following the interaction (p <.001). An analysis of open comments indicates that the subjects perceived the experience as (a) very positive, (b) increasing their knowledge and perception of music for deaf students, (c) helping them better relate to the deaf population, (d) promoting interest in similar experiences and in gaining more information, and (e) eliciting a feeling that future teachers should have similar experiences. Quotes from the subjects are given, and implications for teacher training/music therapy programs are discussed.

The CXCR4 agonist ligand stromal derived factor-1 maintains high affinity for receptors in both Galpha(i)-coupled and uncoupled states

The alpha chemokine receptor CXCR4 and its only characterized chemokine ligand, stromal cell-derived factor-1 (SDF-1), are postulated to be important in the development of the B-cell arm of the immune system. In addition, CXCR4 is a critical coreceptor in support of viral entry by T-cell line tropic strains (X4) of the Human Immunodeficiency Virus Type 1 (HIV-1), viral variants which predominate in some infected individuals in end stage disease. SDF-1 can block X4-tropic HIV-1 infection of CD4+ target cells in vitro, and allelic variants of the human gene encoding SDF-1 in vivo correlate with delayed disease progression. Therefore, CXCR4 may be an appropriate target for therapeutic intervention in acquired immunodeficiency syndrome (AIDS), and knowledge of the pharmacology of SDF-1 binding to its cognate receptor will be important in the interpretation of these experiments. We report here a Kd derived using a competition binding assay of 4.5 nM for CXCR4 endogenously expressed on peripheral blood monocytes and T-cells. This affinity is similar to that which SDF-1 exhibits when binding to endogenous CXCR4 on an established immortal Jurkat T-cell line as well as recombinant CXCR4 transfected into Chinese Hamster Ovary (CHO) cells. We also demonstrate that the determined affinity of SDF-1 for CXCR4 is reflective of its ability to induce a CXCR4-mediated signal transduction in these different cell types. Furthermore, using Bordetella pertussis toxin, we observe that high affinity binding of SDF-1 to CXCR4 is independent of the G-protein coupled state of the receptor, as uncoupling of G-protein did not lead to the appearance of measurable low affinity SDF-1 binding sites. Moreover, binding affinity and receptor number were unaffected by uncoupling for both recombinant and endogenously expressed CXCR4. Thus, SDF-1 is novel among agonist ligands of G protein-coupled receptors in that it appears to have equal affinity for both the G protein-coupled and uncoupled states of CXCR4.

Quantitative determination of a chemically modified hammerhead ribozyme in blood plasma using 96-well solid-phase extraction coupled with high-performance liquid chromatography or capillary gel electrophoresis

Versatile bioanalytical assays to detect chemically stabilized hammerhead ribozyme and putative ribozyme metabolites from plasma are described. The extraction protocols presented are based on serial solid-phase extractions performed on a 96-well plate format and are compatible with either IEX-HPLC or CGE back-end analysis. A validation of both assays confirmed that both the HPLC and the CGE methods possess the required linearity, accuracy, and precision to accurately measure concentrations of hammerhead ribozyme extracted from plasma. These methods should be of general use to detect and quantitate ribozymes from other biological fluids such as serum and urine.

An analysis of trends, perceptions, and use patterns of electronic medical records among US family practice residency programs

BACKGROUND AND OBJECTIVES

This study intended to quantify electronic medical record (EMR) use in family practice residencies, associate program characteristics with EMR use, and identify perceptions and issues about the use of EMRs.

METHODS

A survey was mailed to all 454 US family practice residency programs, with a 72% response rate. The survey, which was pretested and revised, was designed to identify benefits, problems, perceptions, and trends regarding the use of EMRs.

RESULTS

Fifty-five of 329 programs (17%) were using an EMR, while 10 (3%) had used an EMR but discontinued. Programs in the South reported the highest EMR use (21%, 21/99), and those in the North Central region reported the lowest use (11%, 11/102). EMR use was highest in university settings (19%, 15/81), programs offering fellowships (26%, 24/92), new programs (36%, 18/48), and programs that require research (22%, 20/91). Of the 329 programs that responded, 43% (143 programs) reported having information systems (IS) committees. Of the 55 programs currently using EMRs, 78% had at least one full-time equivalent IS technician. Of programs that discontinued use, software inadequacy was the most frequently cited reason (40%, 4/10). Programs that had never used EMR systems (n = 264) were more likely than those that had used EMRs (n = 65) to favorably perceive EMRs with respect to 1) meeting program requirements (44% versus 34%), 2) documenting improved patient care (65% versus 43%), 3) providing a reliable research database (94% versus 55%), and 4) documenting resident experience (92% versus 53%). Of the 264 (80%) programs that had never used an EMR, 172 (65%) plan to implement one.

CONCLUSIONS

EMR use is low among US family practice residency programs, but some success in implementation of EMRs has been achieved. Based on the responses to this survey, use will likely increase from 55 of 329 programs (17%) to 153 of 329 (47%) by 2000.

Computed tomography of necrotizing meningoencephalitis in 3 Yorkshire Terriers

A necrotizing meningoencephalitis of Yorkshire terriers has recently been reported in 6 dogs in Switzerland, 1 dog in Japan and 1 dog in the United States. The purpose of this report is to describe the computed tomographic (CT) findings in 3 dogs with this disease, and to correlate the CT abnormalities with the clinical and pathologic findings in each case. Three Yorkshire Terriers between 2 and 10 years old were evaluated. Physical and neurologic examinations, complete blood count (CBC), serum biochemistry profile, cerebrospinal fluid analysis, and CT scan were performed on all 3 dogs. Brainstem auditory evoked responses (BAER) were evaluated for 2 dogs. Two dogs were euthanized at the owners' request and necropsies were performed. Neurologic examination findings were consistent with a multifocal/diffuse encephalitis involving the cerebrum and brainstem in all 3 dogs. Complete blood count and biochemistry profiles were normal. Elevated protein concentration and a mononuclear pleocytosis were demonstrated in 2 of 3 dogs on cerebrospinal fluid evaluation. Multifocal, extensive areas of decreased opacity throughout the cerebral hemispheres, asymmetric ventriculomegaly, and lack of contrast enhancement were appreciated on CT images of all three dogs. No mass effect was seen. These findings correlated well with pathologic findings at necropsy, which included multiple malacic cavitations within the brain, representing areas of locally extensive necrosis. CT abnormalities in combination with signalment, clinical findings and cerebrospinal fluid analysis should facilitate a presumptive diagnosis of Yorkshire Terrier necrotizing meningoencephalitis.

Economic and gastrointestinal safety comparisons of etodolac, nabumetone, and oxaprozin from insurance claims data from patients with arthritis

This study was conducted to compare the effect of etodolac, nabumetone, and oxaprozin use on gastrointestinal (GI) safety and associated costs based on insurance claims information from practice settings. Data were obtained from a national claims database (MarketScan) for the years 1992 to 1994. The claims data of interest were for patients with arthritis who had used etodolac, nabumetone, or oxaprozin exclusively during a 9-month follow-up period (ONLY groups), or these drugs plus (PLUS groups) the other nonsteroidal anti-inflammatory drugs (NSAIDs) ibuprofen, naproxen, diclofenac, sulindac, piroxicam, ketoprofen, or indomethacin. For each group, we obtained information on the use of inpatient and outpatient services for GI-related events and the associated costs. All GI admissions were classified as NSAID-induced or possibly NSAID-induced events based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) codes. All outpatient upper GI ulcers or bleeding episodes were also identified by specific ICD-9 CM code. There were no significant between-group demographic differences. The proportions of patients with NSAID-induced and possibly NSAID-induced GI admissions were 0.1% and 0.4% for the etodolac-ONLY, 0.3% and 1.0% for the nabumetone-ONLY, and 0.1% and 0.5% for the oxaprozin-ONLY groups, respectively (P > 0.05), and a similar pattern was observed among the PLUS groups. In outpatient settings, 3.9%, 4.2%, and 4.9% of the etodolac-, nabumetone-, and oxaprozin-ONLY patients, respectively (P > 0.05), and 6.0%, 5.3%, and 4.7% of the etodolac-, nabumetone-, and oxaprozin-PLUS patients, respectively, had at least one upper GI ulcer/bleeding claim (P > 0.05). The total health care costs for 9 months were approximately $3000 each for the etodolac-, nabumetone-, and oxaprozin-ONLY groups. Oxaprozin, nabumetone, and etodolac had similar GI-safety and associated-costs profiles based on information from practice settings. Also, in patients who used multiple NSAIDs, the groups did not differ in their GI-safety and cost profiles.

The cost of inpatient endometriosis treatment: an analysis based on the Healthcare Cost and Utilization Project Nationwide Inpatient Sample

OBJECTIVE

To determine the prevalence and cost of endometriosis-related hospitalizations based on the Nationwide Inpatient Sample (NIS) from the Healthcare Cost and Utilization Project (HCUP-3).

STUDY DESIGN

Retrospective analysis based on nationwide clinical practice data.

PATIENTS AND METHODS

Data were obtained for 1991 and 1992 from the HCUP-NIS database, which was a 20% sample of all US hospital discharges. ICD-9 codes (236.0, 617.0 to 617.9) were used to identify females, aged 15 to 54, with endometriosis as a diagnosis. The distribution of endometriosis admissions by admission type, length of stay (LOS), mean total charge, specific types of endometriosis, principal procedures, and other diagnosed diseases was described.

RESULTS

In 1991 and 1992, 37,273 (22.6/1000) and 38,834 (23.7/1000) hospital admissions, respectively, were for endometriosis (as any diagnosis). The average LOS and total hospital charges for endometriosis as the primary diagnosis were 3.8 days and $6,597 for 1991, and 3.5 days and $7,450 for 1992. Most endometriosis admissions occurred in females aged 35 to 49. About 87% of the endometriosis hospitalizations were routine admissions. The most common diagnosis was endometriosis of the uterus (51%); the most common procedure was a total abdominal hysterectomy (55%-60%). Older and African-American patients had the longest LOS and the highest total charges. The estimated total hospitalization costs, as represented by hospital charges, for women with endometriosis as the primary diagnosis in the United States were $504 million for 1991 and $579 million for 1992.

CONCLUSION

Endometriosis-related hospitalization is a major burden on healthcare systems.

The effectiveness of a magnetized water oral irrigator (Hydro Floss) on plaque, calculus and gingival health

The purpose of this study was to evaluate the effects of a magnetized water oral irrigator on plaque, calculus and gingival health. 29 patients completed this double-blind crossover study. Each patient was brought to baseline via an oral prophylaxis with a plaque index < or = 1 and a gingival index < or = 1. Subjects used the irrigator for a period of 3 months with the magnet and 3 months without the magnet. After each 3 month interval, data were collected using the plaque index, gingival index, and accretions index. The repeated measures analysis on plaque, gingival and calculus indices yielded a statistically-significant period effect for PlI (p=0.0343), GI (p=0.0091), and approached significance for calculus (p=0.0593). This meant that the effect of irrigation resulted in a decrease of all indices over time. Therefore, the treatment effect on each index was evaluated using only the measurements obtained at the end of the first period (i.e., assuming a parallel design). Irrigation with magnetized water resulted in 64% less calculus compared to the control group. The reduction was statistically significant (p< or =0.02). The reduction by 27% in gingival index was not statistically significant. The reduction in plaque was minimal (2.2%). A strong positive correlation between the plaque index and the Watt accretion index was observed. The magnetized water oral irrigator could be a useful adjunct in the prevention of calculus accumulation in periodontal patients, but appears to have minimal effect on plaque reduction. The results indicated a clinical improvement in the gingival index, but this was not a statistically significant finding.

Blastomeres show differential fate changes in 8-cell Xenopus laevis embryos that are rotated 90 degrees before first cleavage

To study the mechanisms of dorsal axis specification, the alteration in dorsal cell fate of cleavage stage blastomeres in axis-respecified Xenopus laevis embryos was investigated. Fertilized eggs were rotated 90 degrees with the sperm entry point up or down with respect to the gravitational field. At the 8-cell stage, blastomeres were injected with the lineage tracers, Texas Red- or FITC-Dextran Amines. The distribution of the labeled progeny was mapped at the tail-bud stages (stages 35-38) and compared with the fate map of an 8-cell embryo raised in a normal orientation. As in the normal embryos, each blastomere in the rotated embryos has a characteristic and predictable cell fate. After 90 degrees rotation the blastomeres in the 8-cell stage embryo roughly switched their position by 90 degrees, but the fate of the blastomeres did not simply show a 90 degrees switch appropriate for their new location. Four types of fate change were observed: (i) the normal fate of the blastomere is conserved with little change; (ii) the normal fate is completely changed and a new fate is adopted according to the blastomere's new position: (iii) the normal fate is completely changed, but the new fate is not appropriate for its new position; and (4) the blastomere partially changed its fate and the new fate is a combination of its original fate and a fate appropriate to its new location. According to the changed fates, the blastomeres that adopt dorsal fates were identified in rotated embryos. This identification of dorsal blastomeres provides basic important information for further study of dorsal signaling in Xenopus embryos.

Impact of intuitive theories on feature recruitment throughout the continuum of expertise

Expertise in object domains involves both the perceptual learning of the differentiating and higher order features that are indicative of concepts and the elaboration of intuitive theories. Triad-similarity judgments, feature-salience ratings, and verbal protocols were used to investigate the effects of theories on the recruitment of features across different categorization contexts, as well as the degree to which expert categorization skills transferred to less familiar domains. Whereas novices considered features that indicated overall similarity to be more perceptually salient than were modified parts that indicated taxonomic relations, experts found them equally salient. Experts' theories were instrumental in directing feature recruitment in contexts involving identification, image generation, and similarity decisions. Experts' theories also supported the transfer of categorization skills to related, less familiar domains. The relation of mutual dependence between perceptual learning and theory development throughout the continuum of expertise is considered.

Fates of the blastomeres of the 32-cell stage Pleurodeles waltl embryo

Cell fate of the blastomeres at the 32-cell stage in the Pleurodeles waltl embryo was analyzed by injection of rhodamine or fluorescein lysinated-dextran (RLDx or FLDx). At the tailbud stage, the progeny of each blastomere contributed to more than one germ layer with unequal distribution along the anteroposterior and dorsoventral axis. Such a regionalized positioning of the descendants of the 32-cell blastomeres was found in the neuroectoderm, the epidermis, the notochord, the somites, the lateral plate, and the endoderm, but not in the head mesenchyme, the pronephros, or the blood islands. Results of double labeling of juxtaposed blastomeres showed that cell mixing and rearrangement take place during organ formation. Results are compared with those of the 32-cell stage fate map in Xenopus and Rana and reveal the more restricted fate of 32-cell stage blastomeres in Pleurodeles germ layers.

Development of children's understanding of basic-subordinate inclusion relations

Four studies focused on developmental differences in the representation of basic-subordinate inclusion relations. Tests of comprehension and production of category names, induction, and responses to direct questions pertaining to inclusion revealed a marked developmental gap between the production of subordinate category names and complete understanding of basic-subordinate inclusion relations. However, even 3-year-olds showed rudimentary knowledge of the asymmetry of inclusion. Discrepancies between children's performance on categorization tasks involving familiar and unfamiliar subordinate categories suggest that understanding of the logical nature of inclusion relations is constructed through the integration of categorical knowledge from familiar domains. Interactions among the knowledge base, pragmatic sensitivity, and information processing efficiency in the development of inclusion are discussed.

Effects of varying levels of expertise on the basic level of categorization

Six experiments were conducted on the effects of expertise on basic-level categorization. Individuals with varying levels of knowledge about songbirds generated lists of attributes, named objects, identified and discriminated among object silhouettes, verified category membership at 4 hierarchical levels, and visually identified songbirds primed either by species-specific, related, or unrelated birdsong. Results indicated that the original basic level never lost its privileged status. Expertise increased access to categorical information at the subordinate level for intermediate exports and at both the subordinate and sub-subordinate levels for advanced experts, causing these sublevels to function as basic. Throughout the continuum of expertise, conceptual knowledge interacted with perception. Accordingly, experts attended to different and more subtle perceptual features than novices.

Development of children's understanding of basic-subordinate inclusion relations

Four studies focused on developmental differences in the representation of basic-subordinate inclusion relations. Tests of comprehension and production of category names, induction, and responses to direct questions pertaining to inclusion revealed a marked developmental gap between the production of subordinate category names and complete understanding of basic-subordinate inclusion relations. However, even 3-year-olds showed rudimentary knowledge of the asymmetry of inclusion. Discrepancies between children's performance on categorization tasks involving familiar and unfamiliar subordinate categories suggest that understanding of the logical nature of inclusion relations is constructed through the integration of categorical knowledge from familiar domains. Interactions among the knowledge base, pragmatic sensitivity, and information processing efficiency in the development of inclusion are discussed.

Effects of varying levels of expertise on the basic level of categorization

Six experiments were conducted on the effects of expertise on basic-level categorization. Individuals with varying levels of knowledge about songbirds generated lists of attributes, named objects, identified and discriminated among object silhouettes, verified category membership at 4 hierarchical levels, and visually identified songbirds primed either by species-specific, related, or unrelated birdsong. Results indicated that the original basic level never lost its privileged status. Expertise increased access to categorical information at the subordinate level for intermediate exports and at both the subordinate and sub-subordinate levels for advanced experts, causing these sublevels to function as basic. Throughout the continuum of expertise, conceptual knowledge interacted with perception. Accordingly, experts attended to different and more subtle perceptual features than novices.

Immunocytochemical localization of growth factors and their receptors in human pre-embryos and Fallopian tubes

We utilized indirect immunocytochemistry to demonstrate the presence of growth factors and their receptors in human pre-embryos and Fallopian tubes. In pre-embryos, only transforming growth factor-alpha (TGF-alpha) and the intracellular domain of epidermal growth factor receptor (EGFR) were found at the 4-cell stage. In 8- to 14-cell pre-embryos, TGF-alpha, the intracellular and extracellular domains of EGFR, and insulin-like growth factor-I and its receptor were found. Antibodies against TGF-alpha stained all Fallopian tube specimens, while the extracellular domains of EGFR was only found in specimens from patients with either blood type A or AB. These results suggest a cross-reactivity between the extracellular domain of the EGFR and blood group antigens. Our novel demonstration of growth factor receptor staining in human pre-embryos shows that growth factor receptor localization is dependent on the developmental stage of human pre-embryos. We have also established a potentially important link between the Fallopian tube which secretes growth factors and the localization of growth factor receptors in pre-embryos. These findings are compatible with the hypothesis that tubal secretions are embryotrophic for the early development of the pre-embryo.