Routine radiology-pathology concordance evaluation of CT-guided percutaneous lung biopsies increases the number of cancers identified

BACKGROUND

Routine concordance evaluation between pathology and imaging findings was introduced for CT-guided biopsies.

PURPOSE

To analyze malignancy rate in concordant, discordant, and indeterminate non-malignant results of CT-guided lung biopsies.

METHODS

Concordance between pathology results and imaging findings of consecutive patients undergoing CT-guided lung biopsy between 7/1/2016 and 9/30/2021 was assessed during routine meetings by procedural radiologists. Concordant was defined as pathology consistent with imaging findings; discordant was used when pathology could not explain imaging findings; indeterminate when pathology could explain imaging findings but there was concern for malignancy. Recommendations for discordant and indeterminate were provided. All the malignant results were concordant. Pathology of repeated biopsy, surgical sample, or follow-up was considered reference standard.

RESULTS

Consecutive 828 CT-guided lung biopsies were performed on 795 patients (median age 70 years, IQR 61-77), 423/828 (51%) women. On pathology, 224/828 (27%) were non-malignant. Among the non-malignant, radiology-pathology concordance determined 138/224 (62%) to be concordant with imaging findings, 54/224 (24%) discordant, and 32/224 (14%) indeterminate. When compared to the reference standard, 33/54 (61%) discordant results, 6/30 (20%) indeterminate, and 3/133 (2%) concordant were malignant. The prevalence of malignancy in the three groups was significantly different (p < 0.001). Time to diagnosis was significantly different between patients who reached the diagnosis with imaging follow-up (median 114 days, IQR 69-206) compared to repeat biopsy (33 days, IQR 18-133) (p = 0.01).

CONCLUSION

Routine radiology-pathology concordance evaluation of CT-guided lung biopsy correctly identifies patients at high risk for missed diagnosis of malignancy. Repeat biopsy is the fastest method to reach diagnosis.

CLINICAL RELEVANCE STATEMENT

A routine radiology-pathology concordance assessment identifies patients with non-malignant CT-guided lung biopsy result who are at greater risk of missed diagnosis of malignancy.

KEY POINTS

• A routine radiology-pathology concordance evaluation of CT-guided lung biopsies classified 224 non-malignant results as concordant, discordant, or indeterminate. • The percentage of malignancy on follow-up was significantly different in concordant (2%), discordant (61%), and indeterminate (20%) (p < 0.001). • Time to definitive diagnosis was significantly shorter with repeat biopsy (33 days), compared to imaging follow-up (114 days), p = 0.01.

Evaluation of an Artificial Intelligence Chatbot for Delivery of IR Patient Education Material: A Comparison with Societal Website Content

PURPOSE

To assess the accuracy, completeness, and readability of patient educational material produced by a machine learning model and compare the output to that provided by a societal website.

MATERIALS AND METHODS

Content from the Society of Interventional Radiology Patient Center website was retrieved, categorized, and organized into discrete questions. These questions were entered into the ChatGPT platform, and the output was analyzed for word and sentence counts, readability using multiple validated scales, factual correctness, and suitability for patient education using the Patient Education Materials Assessment Tool for Printable Materials (PEMAT-P) instrument.

RESULTS

A total of 21,154 words were analyzed, including 7,917 words from the website and 13,377 words representing the total output of the ChatGPT platform across 22 text passages. Compared to the societal website, output from the ChatGPT platform was longer and more difficult to read on 4 of 5 readability scales. The ChatGPT output was incorrect for 12 (11.5%) of 104 questions. When reviewed using the PEMAT-P tool, the ChatGPT content scored lower than the website material. Content from both the website and ChatGPT were significantly above the recommended fifth or sixth grade level for patient education, with a mean Flesch-Kincaid grade level of 11.1 (±1.3) for the website and 11.9 (±1.6) for the ChatGPT content.

CONCLUSIONS

The ChatGPT platform may produce incomplete or inaccurate patient educational content, and providers should be familiar with the limitations of the system in its current form. Opportunities may exist to fine-tune existing large language models, which could be optimized for the delivery of patient educational content.

Evaluation of the benefit of rivaroxaban on VOYAGER PAD primary composite of limb, heart and brain outcomes using the global rank and win ratio methods

Background/Introduction

The VOYAGER PAD trial demonstrated that rivaroxaban 2.5 mg twice daily added to background antiplatelet therapy reduced a composite of irreversible harm events of the heart limb and brain versus placebo in patients with symptomatic peripheral artery disease (PAD) after lower extremity revascularization. The primary analysis was performed as time to first event with equal weighting of components including fatal and non-fatal events.

Purpose

Traditional time to event analyses of composites generally assess outcomes with equal weights. Analyses evaluating outcomes using ranked or weighted methods may provide clinicians a mechanism to interpret results including different weighting and enable shared decision making with patients.

Methods

Exploratory analyses of the primary composite outcome were prespecified prior to trial completion/database lock. Two previously described approaches to evaluate composite outcomes by ranking or weighting were utilized. The first was the global rank method which includes ranking all components of the composite by order of clinical importance (Table 1) with a primary and alternative ranking prespecified. Each patient is assigned a rank with the worse rank for worse outcome and for patients with the same outcome, those occurring earlier assigned the worse rank. Van Elteren test for differences between groups was applied stratified by type of procedure and clopidogrel use consistent with the primary trial analysis. The second was the unmatched win ratio method according to Pocock's rule which ranked CV death higher than non-fatal events and then compared pairs of subjects, one from each treatment group for wins and losses for wins and losses as outlined in Table 1. Finkelstein and Schoenfeld statistics were utilized with confidence intervals provided from bootstrapping.

Results

A total of 6564 patients were randomized and all outcomes through the common study end date were counted. The global rank method using both the primary and alternative method yielded a statistically significant superior effect of rivaroxaban versus placebo (p-value for primary ranking 0.0158, p-value for alternative ranking 0.0155). When using the win-ratio approach, there were more wins for rivaroxaban (14.8%) than placebo (12.8%) with 72.4% of patients having no primary component events (Figure 1). The overall win ratio was 1.16 95% CI (1.03–1.30) in favor of rivaroxaban with p=0.0167.

Conclusion(s)

Rivaroxaban significantly reduces acute limb ischemia, amputation, MI, ischemic stroke or CV death in PAD after lower extremity revascularization. Exploratory analyses of this efficacy composite show consistent superiority either when considered as a ranked hierarchy of outcomes with CV death as the worst or whether considering a win-ratio approach ranking CV death as worse followed by non-fatal events. These data support the robustness of the primary trial results when considering ranking of the composite components.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Bayer

Healthy food prescription incentive programme for adults with type 2 diabetes who are experiencing food insecurity: protocol for a randomised controlled trial, modelling and implementation studies

INTRODUCTION

The high cost of many healthy foods poses a challenge to maintaining optimal blood glucose levels for adults with type 2 diabetes mellitus who are experiencing food insecurity, leading to diabetes complications and excess acute care usage and costs. Healthy food prescription programmes may reduce food insecurity and support patients to improve their diet quality, prevent diabetes complications and avoid acute care use. We will use a type 2 hybrid-effectiveness design to examine the reach, effectiveness, adoption, implementation and maintenance (RE-AIM) of a healthy food prescription incentive programme for adults experiencing food insecurity and persistent hyperglycaemia. A randomised controlled trial (RCT) will investigate programme effectiveness via impact on glycosylated haemoglobin (primary outcome), food insecurity, diet quality and other clinical and patient-reported outcomes. A modelling study will estimate longer-term programme effectiveness in reducing diabetes-related complications, resource use and costs. An implementation study will examine all RE-AIM domains to understand determinants of effective implementation and reasons behind programme successes and failures.

METHODS AND ANALYSIS

594 adults who are experiencing food insecurity and persistent hyperglycaemia will be randomised to a healthy food prescription incentive (n=297) or a healthy food prescription comparison group (n=297). Both groups will receive a healthy food prescription. The incentive group will additionally receive a weekly incentive (CDN$10.50/household member) to purchase healthy foods in supermarkets for 6 months. Outcomes will be assessed at baseline and follow-up (6 months) in the RCT and analysed using mixed-effects regression. Longer-term outcomes will be modelled using the UK Prospective Diabetes Study outcomes simulation model-2. Implementation processes and outcomes will be continuously measured via quantitative and qualitative data.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the University of Calgary and the University of Alberta. Findings will be disseminated through reports, lay summaries, policy briefs, academic publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04725630.

PROTOCOL VERSION

Version 1.1; February 2022.

Multimodal Representation Learning via Maximization of Local Mutual Information

We propose and demonstrate a representation learning approach by maximizing the mutual information between local features of images and text. The goal of this approach is to learn useful image representations by taking advantage of the rich information contained in the free text that describes the findings in the image. Our method trains image and text encoders by encouraging the resulting representations to exhibit high local mutual information. We make use of recent advances in mutual information estimation with neural network discriminators. We argue that the sum of local mutual information is typically a lower bound on the global mutual information. Our experimental results in the downstream image classification tasks demonstrate the advantages of using local features for image-text representation learning. Our code is available at: https://github.com/RayRuizhiLiao/mutual_info_img_txt.

A Subsidized Healthy Food Prescription Program for Adults With Type 2 Diabetes Who Are Experiencing Food Insecurity: Protocol for a Randomized Controlled Trial

Objectives

It is vital for individuals with type 2 diabetes (T2DM) to adhere to a healthy dietary pattern to maintain optimal blood glucose levels and overall health. Increasing costs of healthy foods, however, are a barrier to maintaining healthful dietary patterns, particularly for individuals with T2DM who are experiencing food insecurity. Poor diet quality may result in difficulties maintaining optimal blood glucose levels, leading to higher rates of diabetes complications, and increased acute care usage and costs. Although the adverse impacts of food insecurity on maintaining optimal blood glucose levels are well documented, effective strategies to this among individuals with T2DM are lacking. One approach is providing subsidies to purchase healthy foods through subsidized healthy food prescription programs. These programs may help reduce food insecurity and improve diet quality, thereby improving blood glucose levels and reducing diabetes complications over time.

Methods

A parallel group randomized controlled trial will examine the effectiveness of a subsidized healthy food prescription program compared to a healthy food prescription alone in improving average blood glucose levels (primary outcome), and other secondary outcomes among 404 adults who are experiencing food insecurity and persistent hyperglycemia. The subsidized healthy food prescription program consists of two core elements: 1) A one-time healthy food prescription pamphlet that outlines an evidence-based healthy dietary pattern; 2) A healthy food subsidy of $1.50/day/household member to purchase healthy foods in participating supermarkets for 6 months. At baseline and 6-month follow-up, participants will provide responses to sociodemographic and health-related items, and a variety of patient-reported outcomes. Biochemical and physical measurements will also be obtained.

Results

The study's theory of change posits that reducing food insecurity and improving diet quality will be key mediators in improving blood glucose levels, which may reduce diabetes complications, and healthcare usage and costs over time.

Conclusions

The results of this study will demonstrate if a subsidized healthy food prescription program results in meaningful changes in average blood glucose levels and other clinically relevant outcomes.

Funding Sources

Alberta Innovates, Alberta Health Services.

Joint Modeling of Chest Radiographs and Radiology Reports for Pulmonary Edema Assessment

We propose and demonstrate a novel machine learning algorithm that assesses pulmonary edema severity from chest radiographs. While large publicly available datasets of chest radiographs and free-text radiology reports exist, only limited numerical edema severity labels can be extracted from radiology reports. This is a significant challenge in learning such models for image classification. To take advantage of the rich information present in the radiology reports, we develop a neural network model that is trained on both images and free-text to assess pulmonary edema severity from chest radiographs at inference time. Our experimental results suggest that the joint image-text representation learning improves the performance of pulmonary edema assessment compared to a supervised model trained on images only. We also show the use of the text for explaining the image classification by the joint model. To the best of our knowledge, our approach is the first to leverage free-text radiology reports for improving the image model performance in this application. Our code is available at: https://github.com/RayRuizhiLiao/joint_chestxray.

Structured Reporting of IR Procedures: Effect on Report Compliance, Accuracy, and Satisfaction

PURPOSE

To compare effect of free-text versus structured reporting of IR procedures on report quality and report coding and value.

MATERIALS AND METHODS

In this retrospective study, 432 common consecutive free-text IR reports created during 4 months (from September 2013 to December 2013) before implementation of structured reporting (February 2014) and 415 structured IR reports created after implementation (from September 2014 to December 2014) were reviewed to assess ease of use and compliance with reporting requirements for regulatory requirements and coding. IR staff and trainees and referring physicians to IR were surveyed on procedure report attributes, such as detail, quality, and clarity.

RESULTS

Structured reporting increased compliance with reporting fluoroscopy time, radiation dose, and contrast administration compared with free-text reports (402/432 [93.1%] vs 251/415 [60.5%], P < .001; 402/432 [93.1%] vs 242/415 [58.3%], P < .001; and 395/432 [91.4%] vs 257/415 [61.9%], P < .001). Structured reporting decreased addendum requests for insufficient documentation from 43% (121/435 [28%] to 50/415 [12%], P = .01). Most IR physicians found structured reports to require less time to complete (21/26 [81%]), to be easier to complete (23/26 [89%]), and to have a similar or higher level of detail (19/26 [73%]) compared with free-text reports. Referring physicians were more satisfied with structured reports compared with free-text reports (6.9/10 vs 5.6/10, P = .03).

CONCLUSIONS

Structured IR reporting compared with free-text reporting improves compliance with radiation dose and contrast reporting, reporting and coding efficiency, and satisfaction among IR and referring physicians.

Big Data and Machine Learning-Strategies for Driving This Bus: A Summary of the 2016 Intersociety Summer Conference

The 38th radiology Intersociety Committee reviewed the current state and future direction of clinical data science and its application to radiology practice. The assembled participants discussed the need to use current technology to better generate and demonstrate radiologists' value for our patients and referring providers. The attendants grappled with the potentially disruptive applications of machine learning to image analysis. Although the prospect of algorithms' interpreting images automatically initially shakes the core of the radiology profession, the group emerged with tremendous optimism about the future of radiology. Emerging technologies will provide enormous opportunities for radiologists to augment and improve the quality of care they provide to their patients. Radiologists must maintain an active role in guiding the development of these technologies. The conference ended with a call to action to develop educational strategies for future leaders, communicate optimism for our profession's future, and engage with industry to ensure the ethics and clinical relevance of developing technologies.

The relation of hedonic hunger and restrained eating to lateralized frontal activation

Asymmetrical alpha activation in the prefrontal cortex (frontal asymmetry) in electroencephalography (EEG) has been related to eating behavior. Prior studies linked dietary restraint with right frontal asymmetry [1] and disinhibition with left frontal asymmetry [2]. The current study simultaneously assessed restrained eating and hedonic hunger (drive for food reward in the absence of hunger) in relation to frontal asymmetry. Resting-state EEG and measures of restrained eating (Revised Restraint Scale; RRS) and hedonic hunger (Power of Food Scale; PFS) were assessed in 61 non-obese adults. Individually, hedonic hunger predicted left asymmetry. However, PFS and RRS were correlated (r=0.48, p<0.05) and there was a significant interaction between PFS and RRS on frontal asymmetry, p<0.01. Results indicated that those high in hedonic hunger exhibited left asymmetry irrespective of RRS scores; among those low in PFS, only those high in RRS showed right asymmetry. Results were consistent with literature linking avoidant behaviors (restraint) with right-frontal asymmetry and approach behaviors (binge eating) with left-frontal asymmetry. It appears that a strong drive toward palatable foods predominates at a neural level even when restraint is high. Findings suggest that lateralized frontal activity is an indicator of motivation both to consume and to avoid consuming highly palatable foods.

Inter-study reproducibility of cardiovascular magnetic resonance tagging

BACKGROUND

The aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization.

METHODS

Twenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined.

RESULTS

LV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart.

CONCLUSIONS

Intraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location.

TRIAL REGISTRATION

This trial is registered as NCT00005487 at National Heart, Lung and Blood institute.

Points for improvement: performance measurement for glycemic control in diabetes patients in a safety-net population

BACKGROUND

Diabetes complications account for significant worldwide morbidity and mortality. Improving glycemic control decreases microvascular complications, particularly among patients with the worst control. Current performance measures fail to prioritize such individuals. The categorization of glycemic control within a safety-net clinic population was compared using a common performance measure against one derived from a metric accounting for change in glycated hemoglobin (A1c) over time.

METHODS

Retrospective cohort analysis of all patients in a safety-net primary care clinic population quality registry with confirmed diabetes mellitus who had at least two A1c values between 2007 through 2011. Patients were stratified into five groups' on the basis of maximum and earliest A1c level (< 7%, 7% to < 8%, 8% to < 9%, 9% to < 10%, and > 10%). The change in Alc was assessed over time and compared with standard healthcare effectiveness data and information set (HEDIS) performance measures.

RESULTS

Some 1122 patients were included in the analysis, with mean A1c of 7.9%. There was a modest annual decrease in the average A1c, and > 19% of patients improved by 1% or more during each of the previous three years. For patients who had maximum A1c values > or = 10%, there was a significantly greater reduction in A1c (p < .01), which was not reflected in the standard performance measure.

CONCLUSIONS

It is feasible for safety-net clinics to analyze their patients with diabetes by level of disease control on the basis of change in A1c over time. Patients with the worst glycemic control tend to have the greatest improvement but are often overlooked by conventional performance measures. Improved performance measures should focus on longitudinal diabetes control and emphasize reducing risk of complications among patients at highest risk.

Retained intra-abdominal surgical instruments: time to use nascent technology?

Retention of surgical instruments is a possible complication of surgery; moreover, its occurrence has typically been used to denote poor surgical care on the part of the individual surgeon and the healthcare system. In the literature, it is not surprising that instances of retained foreign bodies are underreported to minimize exposure to possible litigation.

Article Commentary: Retained Intra-abdominal Surgical Instruments: Time to Use Nascent Technology?

Retention of surgical instruments is a possible complication of surgery; moreover, its occurrence has typically been used to denote poor surgical care on the part of the individual surgeon and the healthcare system. In the literature, it is not surprising that instances of retained foreign bodies are underreported to minimize exposure to possible litigation.

Training and Management of a Multisite Neuropsychological Testing Protocol for the Department of Veterans Affairs Cooperative Study Evaluating on- and Off-pump Coronary Artery Bypass Graft Procedures

Research study coordinators from 17 sites participating in a cardiac surgery study were trained to administer and score a brief neuropsychological test battery. Results were sent to the study's centralized laboratory for review and feedback. The average examiner errors on the first six protocols were compared with the average errors on the last six protocols over 12 months for each site. Overall, errors for the first six protocols were 4.42, and errors for the last six protocols were 1.83, representing a significant overall decline. Errors for instruction, administration, and recording showed a significant decrease over time. Despite ongoing feedback to examiners, scoring errors did not decline significantly overall; this suggests that a review of all protocols is necessary to achieve reliable scoring. However, when examiners' number of protocols completed was compared with number of scoring errors per protocol, there was a trend for examiners who had completed more protocols to show more improvement in scoring.

A multicenter retrospective 3D study of serial complete unilateral cleft lip and palate and complete bilateral cleft lip and palate casts to evaluate treatment: part 1--the participating institutions and research aims

OBJECTIVE

To compare the multicenter retrospective and prospective spatiotemporal (4D) serial analyses of complete unilateral (CUCLP) and complete bilateral (CBCLP) cleft lip and palate casts that had undergone different treatment procedures. The involved institutions are Miami Craniofacial Anomalies Foundation, South Florida Cleft Palate Clinic; University Hospital of Nijmegen Cleft Palate Center; Free University of Amsterdam Cleft Palate Center; Academic Hospital (Dijkzigt/Sophia) Rotterdam Cleft Palate Center; Center for Craniofacial Anomalies, University of Illinois College of Medicine; Cleft Palate Center, Sahlgrenska University Hospital, Göteborg, Sweden; and Children's Memorial Medical Center, Northwestern University Cleft Palate Institute.

DESIGN

Using serial casts of the upper jaw and an electromechanical digitizer with special Cad-Cam software (CadKey), the occlusal relationships and morphometric palatal growth changes that occur under the influence of presurgical orthopedics and various surgical procedures will be studied. It is anticipated that 3D geometric data extracted from serial casts will identify the important geometric palatal parameters present before cleft surgical closure, which will supply objective criteria for establishing a scientific basis for improved surgical therapy. This research study will test three hypotheses: (1) Conservative (varying the timing of surgical cleft closure according to the size of the cleft space) lip and palatal surgery will permit "catch-up" palatal growth and normalize palatal growth and development. (2) The amount of mucoperiosteal tissue relative to the size of the cleft space is important in determining the timing of palatal surgery, as it influences the degree of scarring and ultimately the palate's adult size and form. (3) Presurgical orthopedics (the use of appliances soon after birth) can stimulate palatal growth beyond its normal growth potential.

RESULTS

In a previous project and again after reviewing the data already collected during the first year of this study, it has been shown that incremental changes in size of palatal segments in CUCLP and CBCLP cases prior to surgery vary slightly. The CBCLP cases grow slightly faster than CUCLP cases before surgery, but growth of the CBCLP cases decreases in acceleration after surgery. Reasons for these differences will be determined when more cases are analyzed and subjected to biostatistical analysis.

Shape changes in the cleft palate maxilla: a longitudinal study

OBJECTIVE

The purpose of this study was to compare the shape of the maxilla in Norma lateralis of cleft lip and palate (CLP) patients with non-CLP controls matched for sex and age. This study utilized elliptical Fourier functions to assess the presence of residual shape changes in the cleft palate maxilla after treatment, compared with controls.

DESIGN

Longitudinal data (n = 25) were available from the Miami Craniofacial Anomalies Foundation. From these data, two samples were selected: group I (mean age and SD, 5.06 +/- 1.82 years) after lip surgery and the initiation of palate surgery and group II (16.58 +/- 2.42 years) well after the conclusion of surgery. Twenty-two of these patients were matched with controls (5.11 +/- 1.33 and 15.91 +/- 2.25 years, respectively). The maxillary outline as seen on the lateral radiograph was (1) traced, (2) fitted with a series of 48 closely placed points, (3) digitized, and (4) submitted to a specially written routine that computes elliptical Fourier functions (EFFs). These EFFs are close analogs of the bounded maxillary outline as judged by the residual or difference between the observed points and the predicted points generated by the Fourier function. Each maxillary outline was subsequently standardized for size and corrected for positioning in two-dimensional space.

RESULTS AND CONCLUSIONS

Utilizing a three-way multivariate analysis of variance, statistically significant shape differences were obtained for both young and older groups, as well as between the CLP and controls. No significant gender differences were found. Morphological differences consisted of a posterior repositioning of the nasal crest aspect in the CLP cases. These results suggest that although a clinically satisfactory treatment result was obtained, differences in maxillary shape remain.

In search of the harmonious face: Apollo revisited, with an examination of the indications for retrograde maxillary displacement

A historical review of our perception of facial flatness and convexity and what constitutes "a pleasing face," both in North America and internationally, is provided. Attractive faces may range from slightly flat ("Apollonian") to mildly bimaxillary protrusive, but marked deviations in either direction, from the dish face to extreme bimaxillary protrusion, constitute a deformation and warrant combined orthodontic and surgical treatment. Technical aspects of segmental and total maxillary setback are presented, along with four representative cases.

A new direction for cleft palate research

Successful outcomes in the treatment of complete unilateral cleft-lip and palate (CUCL/P) and complete bilateral cleft lip and palate (CBCLP) are not obtained universally, despite significant improvements in surgical techniques over the past three decades. In particular, deficient palatal growth may occur even when expert surgical treatment is rendered. The factors which contribute most significantly to unfavorable growth outcomes remain obscure.

A comparison of treatment results in complete bilateral cleft lip and palate using a conservative approach versus Millard-Latham PSOT procedure

Conservative non-presurgical orthopedic treatment in complete bilateral cleft lip and palate (CBCLP) cases were compared with those treated will the Millard-Latham (M-L) method, which involves the presurgical mechanical retraction of the protruding premaxilla using pinned palatal appliances. In conservatively treated cases, a head bonnet with an external elastic is sometimes used before surgical lip closure to ventroflex the premaxilla thereby reducing tension at the surgical sites. The M-L method involves premaxillary bodily retraction followed by a gingivo-periosteoplasty. In both series of cases the palatal cleft (hard and soft) is closed for patients aged 18 to 30 months using a modified von Langenbeck procedure. A secondary alveolar bone graft is only performed in the conservatively treated series for patients aged 7 to 9 years. Although the premaxilla in 2 of 29 conservatively treated cases were retruded and in anterior crossbite by 10 to 12 years of age, all M-L cases were retruded by 9 years of age requiring maxillary protraction. In the M-L cases 90% showed bony bridging of the alveolar cleft with frequent loss of the lateral incisor space; surgical closure of the nasal floor is facilitated, and early aesthetic improvement is followed by midfacial retrusion.

Ethical issues in the case of surgical repair of cleft palate

There are some advantages to prospective randomized clinical trials (PRCT) to resolve some limited clinical problems. But, when this method is used to determine the best surgical procedure to close the palatal cleft space, there are strong ethical considerations that cannot be overcome. There are two basic problems. The first is having the surgeon perform surgical procedures which he/she does not believe is the treatment of choice or that can be performed as skillfully as others, even after demonstrations. Secondly, this method does not consider the theoretical aspect that many clefts within the same cleft type are different in the relative size of cleft space to size of soft tissue available for closing the cleft space, thereby creating different degrees of scarring. Different outcomes to the same surgery must, therefore, result irrespective of the surgeons' skills or treatment plans. Retrospective research studies, whether they involve one or more institutions, have been and are still very valuable in improving the knowledge base of all areas of cleft palate habilitation.

The monobloc frontofacial advancement: do the pluses outweigh the minuses?

The results of 32 patients who underwent transcranial monobloc frontofacial advancement by the senior author (Wolfe) are examined. Fifteen of the patients were Crouzon's and 17 were Apert's, 14 of whom also underwent simultaneous facial bipartition. The ages ranged from 7 months to 14 years. Although a transcranial facial advancement carries with it substantial risks, with careful consideration of airway control, the anterior cranial base dura, and the retrofrontal dead space, the procedure is recommended for carefully selected patients. The indications and contraindications for the procedure in various age groups are given.

Ultraviolet-visible transient spectroscopy of bacteriorhodopsin mutants. Evidence for two forms of tyrosine-185----phenylalanine

The photocycle kinetics of the bacteriorhodopsin mutant Tyr-185----Phe has been investigated by UV-visible transient spectroscopy. Flash-induced spectral changes were measured from 100 ns to 500 ms using a gated optical multichannel analyzer on protein samples that were reconstituted in vesicles with Halobacterium halobium lipids. Tyr-185----Phe exhibits a pH-dependent absorbance spectrum reflecting contributions from two different species. At pH 6, the dominant photocycling species has a lambda max near 610 nm although the absorption maximum of light-adapted Tyr-185----Phe is at 581 nm. This red-shifted species does not form any M-like intermediate and undergoes a photocycle similar to that observed for deionized blue membrane. At pH 8, the dominant photoactive form exhibits a lambda max near 550 nm. This purple species, which is blue shifted 20 nm relative to wild-type bacteriorhodopsin, exhibits a photocycle similar to the wild type. However, M formation occurs in 8 microseconds, approximately three times faster than wild-type bacteriorhodopsin at pH 8. In addition, an unusually long lived intermediate absorbing at 610 nm is observed at high pH. In the UV region, a broad band near 300-310 nm is absent in the mutant relative to wild type, consistent with earlier measurements made at low temperature which suggest that Tyr-185 undergoes a change in protonation. Steady-state proton pumping action spectra indicate that the 550 nm species does transport protons but that the blue species is inactive. These results are discussed in terms of a model that hypothesizes that Tyr-185 is located close to the bacteriorhodopsin chromophore and stabilizes the interaction of helices F and G through formation of a polarizable bond with Asp-212.

Effect of inspired air temperature on genioglossus activity during nose breathing in awake humans

Experimental data suggest the presence of sensory receptors specific to the nasopharynx that may reflexly influence respiratory activity. To investigate the effects of inspired air temperature on upper airway dilator muscle activity during nose breathing, we compared phasic genioglossus electromyograms (EMGgg) in eight normal awake adults breathing cold dry or warm humidified air through the nose. EMGgg was measured with peroral bipolar electrodes during successive trials of cold air (less than or equal to 15 degrees C) and warm air (greater than or equal to 34 degrees C) nasal breathing and quantified for each condition as percent activity at baseline (room temperature). In four of the subjects, the protocol was repeated after topical nasal anesthesia. For all eight subjects, mean EMGgg was greater during cold air breathing than during baseline (P less than 0.005) or warm air breathing (P less than 0.01); mean EMGgg during warm air breathing was not significantly changed from baseline. Nasal anesthesia significantly decreased the mean EMGgg response to cold air breathing. Nasal airway inspiratory resistance, measured by posterior rhinomanometry in six subjects under similar conditions, was no different for cold or warm air nose breathing [cold 1.4 +/- 0.7 vs. warm 1.4 +/- 1.1 (SD) cmH2O.l-1.s at 0.4 l/s flow]. These data suggest the presence of superficially located nasal cold receptors that may reflexly influence upper airway dilating muscle activity independently of pressure changes in awake normal humans.

A comparison of two methods of prompting in training discrimination of communication book pictures by autistic students

Two methods of prompting were compared for their relative effectiveness in teaching a group of autistic students to discriminate line drawings used in picture communication books. All four students required fewer trials to meet the task criterion using a delayed-prompting technique. Further, students made significantly more errors in the fading-of-prompts design than in the delayed-prompting design. The high rate of errors in faded-prompt sessions resulted in some students displaying aberrant behaviors. The results are discussed in terms of effectiveness of the two teaching methodologies, as well as the consequences of error patterns. Suggestions are made for further research.

Substitution of membrane-embedded aspartic acids in bacteriorhodopsin causes specific changes in different steps of the photochemical cycle

Millisecond photocycle kinetics were measured at room temperature for 13 site-specific bacteriorhodopsin mutants in which single aspartic acid residues were replaced by asparagine, glutamic acid, or alanine. Replacement of aspartic acid residues expected to be within the membrane-embedded region of the protein (Asp-85, -96, -115, or -212) produced large alterations in the photocycle. Substitution of Asp-85 or Asp-212 by Asn altered or blocked formation of the M410 photointermediate. Substitution of these two residues by Glu decreased the amount of M410 formed. Substitutions of Asp-96 slowed the decay rate of the M410 photointermediate, and substitutions of Asp-115 slowed the decay rate of the O640 photointermediate. Corresponding substitutions of aspartic acid residues expected to be in cytoplasmic loop regions of the protein (Asp-36, -38, -102, or -104) resulted in little or no alteration of the photocycle. Our results indicate that the defects in proton pumping which we have previously observed upon substitution of Asp-85, Asp-96, Asp-115, and Asp-212 [Mogi, T., Stern, L. J., Marti, T., Chao, B. H., & Khorana, H. G. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 4148-4152] are closely coupled to alterations in the photocycle. The photocycle alterations observed in these mutants are discussed in relation to the functional roles of specific aspartic acid residues at different stages of the bacteriorhodopsin photocycle and the proton pumping mechanism.