Towards Automated Dosimetric Analysis of the Bladder Trigone: Deep-Learning-Based Joint Segmentation and Landmark Localization

PURPOSE/OBJECTIVE(S)

The bladder trigone dosimetry is hypothesized to have a stronger correlation with post-SBRT urinary toxicity than that of the entire bladder. However, the trigone tends to move significantly between simulation and daily treatment. Its small size, large daily motion, and proximity to the target lead to potentially consequential but unaccounted-for dosimetric uncertainties. Manual segmentation of the structure can be inconsistent and time-consuming, even with MR-guided RT. Here, we propose and demonstrate a deep-learning-based framework for joint segmentation and landmark localization to support deformable registration and comprehensive dosimetric analysis.

MATERIALS/METHODS

A total of 30 patients were randomly selected for training, and 20 were held out for testing. Each patient had 1 simulation and 5 daily pre-treatment images obtained from a clinical 0.35T MR Linac. The trigone is defined as the triangular bladder section among three landmarks (2 ureteral orifices and the internal urethral orifice). In the manual contouring process, the 3 landmarks were identified first, followed by trigone segmentation. The proposed joint method uses a modified 3D nnU-Net with 2 decoders, one for segmentation and the other for landmark localization. The shared encoder is expected to extract features useful for both tasks. The joint framework was compared with a baseline method using two separate 3D nnU-Nets for landmark localization and trigone segmentation, respectively. Since the trigone is small (∼2% of the bladder volume), we further experimented with a second-stage prediction mimicking the human contouring process. The predicted landmarks from the first stage were used to crop the trigone region, and a second network was trained on cropped images. Evaluation metrics included the Dice score, 95% Hausdorff distance (HD95), and average surface distance (ASD) for segmentation, and Euclidean distance (ED) between the predicted and ground truth landmarks for localization.

RESULTS

The quantification metrics are summarized in the table below. The joint approach shows similar Dice performance to the baseline method but markedly better HD95 by 13%. For landmark localization, the proposed method is similar to the baseline, but the integration of the segmentation task stabilizes the training process. The two-stage approach further improves HD95, ASD, and ED by 27%, 24%, and 19%.

CONCLUSION

Combining segmentation and landmark localization exhibits a synergistic effect. The proposed two-stage approach provided additional improvement. Future studies will explore the deformable registration of the trigone based on the segmentation and landmark detection, as well as analyze cumulated dose distribution.

Validating the Perceived Active School Travel Enablers and Barriers - Child (PASTEB-C) questionnaire

OBJECTIVES

Presently, child-specific tools and instruments related to active school travel (AST) are lacking. This methodological shortcoming often contributes to suboptimal AST behaviour evaluations and intervention programming. The aim of this paper was to develop and validate a theoretically informed child-specific scale regarding multiple perceived barriers and enablers known to impact children's participation in AST.

STUDY DESIGN

Mixed methods.

METHODS

A mixed-methods and multistudy scale development approach featuring the application of social-ecological theory, a validation pilot study (n = 80), and test-retest study (n = 96) was conducted in collaboration with children in Ontario, Canada. In tandem with completing cognitive interviews and online surveys, multiple analyses, including a qualitative thematic analysis, along with weighted Cohen's kappa, Cronbach's alpha, and confirmatory factor analysis were undertaken.

RESULTS

Qualitative analyses of the developed tool addressed face validity concerns related to the response options and definitions of terms used. Following the reliability analyses of 40 items, two confirmatory factor analyses were run to assess the construct validation of perceived AST barriers and enablers, and resulted in the development of the 24-item Perceived Active School Travel Enablers and Barriers - Child (PASTEB-C) questionnaire.

CONCLUSION

The developed PASTEB-C questionnaire may be used to inform the programming and development of AST interventions, as well as conduct child-specific AST research.

Lung Metastasis From Uterine Leiomyosarcoma: An Asymptomatic Presentation for a Rare Tumor

Uterine leiomyosarcoma (ULC) is an uncommon neoplasm characterized by poor prognosis, it can predispose to distant metastasis, causing various symptomatic presentations. We present a unique case of a large heterogeneous mass in the lung cavity arising from a ULC, with complete absence of pulmonary symptoms and with concurrent coronavirus disease 2019 (COVID-19) infection. A high degree of clinical suspicion is required for ULC with accompanying metastasis.

Minimally Invasive Neuropathic Reconstruction (MiNR study)

Category:

Diabetes; Ankle; Hindfoot; Midfoot/Forefoot; Trauma; Other

Introduction/Purpose:

Charcot neuroarthropathy (CN) is caused by peripheral neuropathy leading to undetected injuries of the bones, joints, and soft tissues [1]. Currently, the surgical management of CN is guided by small retrospective case series and expert opinions [2, 3, 5, 7, 32]. Traditional reconstructive surgical approaches involve large, open incisions to remove bone, as well as the use of internal and external fixation in an attempt to fuse dislocated joints. Theoretically 1ninimally invasive surgery takes the tension off the soft tissues which ensures that there is still good tissue cover without compromising the blood supply to the skin and reduces risk of infection [25]. Also, minimally invasive techniques are associated with fewer wound complications and fewer nerve complications when compared to open classical approaches [9, 10]. The purpose of our retrospective study is to determine if open versus minimally invasive Charcot foot reconstruction fusion rates and complication rates are equivalent or better in the minimally invasive group.

Methods:

We define minimally invasive surgery as any percutaneous technique, simple exostectomy, arthrodesis, and reconstruction with relatively small surgical incisions.

Results:

The study analyzed the pre and post operative course of 44 patients. The study included 25 male and 19 female participants between the ages of 41 - 89 and a mean participant age of 67.5. We looked at patients who underwent treatment for Charcot's foot and found that 68% of these patient had diabetes mellitus. Of the surgical patients 32% were minimally invasive, 55% open and I 3% both minimally invasive and open combination.

Conclusion:

At 6 months there was no significant difference in the fusion rates or complications across the open, MIS and combination groups. Further study is warranted to determine the optimal candidate and scenario for such technique.

Neurosurgery Lectures Benefit from a Flipped Class Approach

BACKGROUND

In a flipped classroom, students learn lecture material before class then participate in active learning during in-person sessions. This study examines preferences for flipped classroom activities during a neurosurgery presentation on Traumatic Brain Injury (TBI).

METHODS

225 third- and fourth-year medical students on their core Neurology rotation watched an online podcast about TBI before meeting for in-person, active learning activities with a neurological surgeon. Before and after the class, students were given rank-based surveys with an optional section for comments. The initial survey assessed preference for specific active learning activities, and the final survey assessed satisfaction with the experience. The students also answered an online 20-question post-lecture test as part of the standard Neurology class assessment.

RESULTS

Every student scored over 90% on the post-lecture test. Of the 81 students who answered the first survey, most students (83.95%) strongly preferred or preferred case scenarios with group discussion. The average Likert score for case scenario preference (4.37/5) was significantly higher than the score for all other activities (p < 0.05). Of the 207 students who answered the second survey, 80.19% of students reported that they would probably or definitely like to see more flipped classroom activities.

CONCLUSIONS

Medical students highly preferred case scenarios because, according to their comments, this method was relevant to real-life situations and led to higher information retention. This information suggests that the flipped classroom model for neurosurgical based lectures is preferred, beneficial, and should incorporate case scenarios. This methodology may also apply to neurosurgical residency training.

Automated Segmentation and Connectivity Analysis for Normal Pressure Hydrocephalus

Objective and Impact Statement. We propose an automated method of predicting Normal Pressure Hydrocephalus (NPH) from CT scans. A deep convolutional network segments regions of interest from the scans. These regions are then combined with MRI information to predict NPH. To our knowledge, this is the first method which automatically predicts NPH from CT scans and incorporates diffusion tractography information for prediction. Introduction. Due to their low cost and high versatility, CT scans are often used in NPH diagnosis. No well-defined and effective protocol currently exists for analysis of CT scans for NPH. Evans' index, an approximation of the ventricle to brain volume using one 2D image slice, has been proposed but is not robust. The proposed approach is an effective way to quantify regions of interest and offers a computational method for predicting NPH. Methods. We propose a novel method to predict NPH by combining regions of interest segmented from CT scans with connectome data to compute features which capture the impact of enlarged ventricles by excluding fiber tracts passing through these regions. The segmentation and network features are used to train a model for NPH prediction. Results. Our method outperforms the current state-of-the-art by 9 precision points and 29 recall points. Our segmentation model outperforms the current state-of-the-art in segmenting the ventricle, gray-white matter, and subarachnoid space in CT scans. Conclusion. Our experimental results demonstrate that fast and accurate volumetric segmentation of CT brain scans can help improve the NPH diagnosis process, and network properties can increase NPH prediction accuracy.

Comparison of liver biopsies before and after direct-acting antiviral therapy for hepatitis C and correlation with clinical outcome

Direct-acting antivirals (DAA) have replaced interferon (IFN)-based therapies for hepatitis C virus. In this retrospective clinical study, we examined differences in histopathologic features in paired liver biopsies collected from the same patient before and after DAA and correlated these findings with clinical outcome. Biopsies (n = 19) were evaluated by quantitative imaging analysis to measure steatosis and fibrosis. Most patients had decreased steatosis in their post-treatment, follow-up biopsies. However, one patient had a striking increase in steatosis (from 0.86 to 6.32%) and later developed decompensated cirrhosis and hepatocellular carcinoma (HCC). This patient had a marked increase in fibrosis between biopsies, with a CPA of 6.74 to 32.02. Another patient, who already had bridging fibrosis at the time of her pre-treatment biopsy, developed cholangiocarcinoma after DAA. Even though the overall inflammatory activity in the post-treatment biopsies significantly decreased after treatment, 60% of patients had persistent portal lymphocytic inflammation. In summary, DAAs decreased steatosis and hepatic inflammation in most patients, although some may have persistence of lymphocytic portal inflammation. Patients known to have advanced fibrosis at treatment initiation and who have other risk factors for ongoing liver injury, such as steatosis, should be followed closely for the development of adverse outcomes, such as portal hypertension and primary liver cancers.

0807 NREM Parasomnias: Retrospective Analysis Of Treatment And Outcomes

Introduction

NREM parasomnias are relatively common among children and sometimes persist in adulthood. These behaviors may result in injury or have negative impacts on functioning and quality of life thus necessitating treatment. The treatment is challenging given the lack of evidence for frequently used medications such as benzodiazepines (BDZ) or tricyclic antidepressants (TCA). The aim of this retrospective analysis is to determine the most frequently prescribed medications for treatment of NREM parasomnias and evaluate reported outcomes.

Methods

We performed a retrospective chart review of all patients with NREM parasomnia diagnosed within BWH clinics examining the date of diagnosis, date of starting therapy, comorbidities, type of medication prescribed, and the reported change in symptoms or side effects at the individual’s follow-up visits.

Results

From 2012 to 2019, 123 patients (64 females, 59 male) at BWH clinics received the diagnosis of NREM parasomnia, including sleepwalking and night terrors. Mean age was 44. Comorbidities included depression=16, anxiety=32, seizures=6, RLS=9, epilepsy=5, insomnia=29, and OSA=57. Initial treatment included safety counseling (72), BDZ (7), TCA (4), and treatment of comorbidity (23). Treatment of OSA only (n=15) was effective in 66% (n=10) and 33% were lost to follow up. Of those with OSA treatment plus BDZ (n=6), treatment was effective in 50% (n=3). Of those receiving BDZ only (n=7), treatment was effective in 43%. Of those receiving Melatonin (8),treatment was effective among 62.5% (n=5). TCAS (n=4) were effective in 3 patients (75%). Treatment of comorbid conditions without pharmacotherapy (23) was effective in 35% (n=8) while the remaining 65% (n=15) were lost to follow up.

Conclusion

Treating comorbid conditions such as OSA, insomnia, RLS, depression, and anxiety is a frequent treatment strategy. Additional pharmacologic treatment most commonly includes melatonin, BDZs, and TCAs.

Support

None

Establishment and Benefits of a Normal Pressure Hydrocephalus Support Group on Patient Education and Experience

Introduction: Normal pressure hydrocephalus (NPH) is a debilitating, neurological condition that can lead to mental deterioration. With the diagnosis and treatment of NPH constantly evolving and its symptoms worsening with age, education for patients and their families is crucial. In this study, we aim to explore the potential educational benefits of a physician-led NPH support group.

Methods: Between December 2015 and November 2018, six semiannual NPH support group meetings were held for patients and their families. Attendees, ages 20-90, completed a Likert scale-based survey designed to assess the support group’s educational benefits using the following primary outcome variables: (1) subjective knowledge, (2) perceived utility/efficacy, and (3) patient satisfaction.

Results: Our survey data suggests that patients and their family members agree on the efficacy of the support group in learning about NPH. They felt that the support group served its purpose and improved their comfort/knowledge regarding NPH. There was consensus about sustaining and maintaining the support group for the future. Of 65 survey responses, the composite average score of questions pertaining to subjective knowledge, perceived utility/efficacy, and patient satisfaction was 4.5 out of 5.0.

Conclusion: We demonstrated that support groups are effective in educating the adult NPH population and their family/friends about NPH onset and treatment. Enhanced educational awareness for patients and families can help patients cope with their neurological condition and improve patient adherence to follow-up and physician recommendations.

Sequence conservation predicts T cell reactivity against ragweed allergens

BACKGROUND

Ragweed is a major cause of seasonal allergy, affecting millions of people worldwide. Several allergens have been defined based on IgE reactivity, but their relative immunogenicity in terms of T cell responses has not been studied.

OBJECTIVE

We comprehensively characterized T cell responses from atopic, ragweed-allergic subjects to Amb a 1, Amb a 3, Amb a 4, Amb a 5, Amb a 6, Amb a 8, Amb a 9, Amb a 10, Amb a 11, and Amb p 5 and examined their correlation with serological reactivity and sequence conservation in other allergens.

METHODS

Peripheral blood mononuclear cells (PBMCs) from donors positive for IgE towards ragweed extracts after in vitro expansion for secretion of IL-5 (a representative Th2 cytokine) and IFN-γ (Th1) in response to a panel of overlapping peptides spanning the above-listed allergens were assessed.

RESULTS

Three previously identified dominant T cell epitopes (Amb a 1 176-191, 200-215, and 344-359) were confirmed, and three novel dominant epitopes (Amb a 1 280-295, 304-319, and 320-335) were identified. Amb a 1, the dominant IgE allergen, was also the dominant T cell allergen, but dominance patterns for T cell and IgE responses for the other ragweed allergens did not correlate. Dominance for T cell responses correlated with conservation of ragweed epitopes with sequences of other well-known allergens.

CONCLUSIONS AND CLINICAL RELEVANCE

These results provide the first assessment of the hierarchy of T cell reactivity in ragweed allergens, which is distinct from that observed for IgE reactivity and influenced by T cell epitope sequence conservation. The results suggest that ragweed allergens associated with lesser IgE reactivity and significant T cell reactivity may be targeted for T cell immunotherapy, and further support the development of immunotherapies against epitopes conserved across species to generate broad reactivity against many common allergens.

Definition of a pool of epitopes that recapitulates the T cell reactivity against major house dust mite allergens

BACKGROUND

Allergens from house dust mites (HDM) are a common cause of asthma. Der p and Der f from Dermatophagoides sp. are strong immunogens in humans. Allergen extracts are used to study T helper (Th2) cell responses to HDM, which are implicated in the development and regulation of allergic disease.

OBJECTIVE

To define an epitope mixture that recapitulates, and might substitute for, HDM extract in terms of detecting and characterizing Th2 cell responses.

METHODS

Peripheral blood mononuclear cells (PBMC) from 52 HDM allergic and 10 non-allergic individuals were stimulated with HDM extracts and assayed with a set of 178 peptides spanning mite allergens group Der p 1, 2, 23 and Der f group 1 and 2 allergens. A pool of the most dominant T cell epitopes identified in the present study and from published literature was assembled and tested for ex vivo T cell responses. Correlation with HDM-specific IgE titres was examined.

RESULTS

Patterns of T cell reactivity to Der p and Der f - derived peptides revealed a large number of epitopes. Clear patterns of immunodominance were apparent, with HDM allergen group 1 and 2 dominant over group 23. Furthermore, within a given antigen, 6-11 epitopes accounted for the vast majority of responses. Based on these results and published data, a comprehensive dust mite pool (DMP) of epitopes was designed and found to allow detection of ex vivo T cell responses. DMP ex vivo reactivity correlated with HDM-specific IgE titres and was similar to that detected with commonly used HDM extracts. Ex vivo DMP stimulation was associated with a predominant Th2 response in allergic donors, and minor reactivity of T cells producing IFNγ, IL17 and IL10.

CONCLUSIONS & CLINICAL RELEVANCE

A detailed map of Der p and Der f antigens defined a pool of epitopes that can be used to detect ex vivo HDM responses.

Epidemic Spread of Symbiotic and Non-Symbiotic Bradyrhizobium Genotypes Across California

The patterns and drivers of bacterial strain dominance remain poorly understood in natural populations. Here, we cultured 1292 Bradyrhizobium isolates from symbiotic root nodules and the soil root interface of the host plant Acmispon strigosus across a >840-km transect in California. To investigate epidemiology and the potential role of accessory loci as epidemic drivers, isolates were genotyped at two chromosomal loci and were assayed for presence or absence of accessory "symbiosis island" loci that encode capacity to form nodules on hosts. We found that Bradyrhizobium populations were very diverse but dominated by few haplotypes-with a single "epidemic" haplotype constituting nearly 30 % of collected isolates and spreading nearly statewide. In many Bradyrhizobium lineages, we inferred presence and absence of the symbiosis island suggesting recurrent evolutionary gain and or loss of symbiotic capacity. We did not find statistical phylogenetic evidence that the symbiosis island acquisition promotes strain dominance and both symbiotic and non-symbiotic strains exhibited population dominance and spatial spread. Our dataset reveals that a strikingly few Bradyrhizobium genotypes can rapidly spread to dominate a landscape and suggests that these epidemics are not driven by the acquisition of accessory loci as occurs in key human pathogens.

Action-Oriented Population Nutrition Research: High Demand but Limited Supply

BACKGROUND

The relatively rapid ascendancy of nutrition and health on policy agendas, along with greater emphasis on accountability and results, has stimulated interest in new forms of research to guide the development and implementation of effective policies, programs, and interventions-what we refer to as action-oriented research. To date, action-oriented research in the nutrition field is thought to be the exception rather than the rule, but empirical evidence to support this claim is lacking.

METHODS

We conducted a survey of selected journals in nutrition and public health to assess the extent and nature of population nutrition research published in 2012 that embodied 5 defined characteristics of action-oriented research in relation to: (1) topic(s) of study, (2) processes/influences, (3) actors, (4) methods, and (5) approaches. We identified 762 articles from the 6 selected nutrition journals and 77 nutrition-related articles from the 4 selected public health journals that met our search criteria.

RESULTS

Only 7% of the 762 papers in nutrition journals had at least 1 of the 5 action-oriented research characteristics, compared with 36% of the 77 nutrition-related papers in the public health journals. Of all 80 articles that had at least 1 action-oriented research characteristic, only 5 articles (6.25%) embodied all 5 characteristics. Articles with action-oriented research covered a broad range of topics and processes/influences, including policy, workforce development, and schools, as well as actors, such as program staff, store owners, parents, and school staff. In addition, various research methods were used, such as stakeholder analysis, ethnographic narrative, iterative action research, and decision tree modeling, as well as different approaches, including participant-observer and community-based participatory research.

CONCLUSIONS

Action-oriented research represents a small fraction of articles published in nutrition journals, especially compared with public health journals. This reinforces recent calls to expand population nutrition research agendas to more effectively inform and guide the initiation, development, implementation, and governance of policies, programs, and interventions to address the varied forms of nutrition-related problems. With heightened attention to the magnitude and importance of nutrition problems worldwide, there are substantial reasons and opportunities to incentivize and support such expansion.

Fast three-dimensional superimposition of cone beam computed tomography for orthopaedics and orthognathic surgery evaluation

The aim of this study was to validate a method for fast three-dimensional (3D) superimposition of cone beam computed tomography (CBCT) in growing patients and adults (surgical cases). The sample consisted of CBCT scans of 18 patients. For 10 patients, as the gold standard, the spatial position of the pretreatment CBCT was reoriented, saved as a reoriented volume, and then superimposed on the original image. For eight patients, four non-growing and four growing, the pre- and post-treatment scans were superimposed. Fast voxel-based superimposition was performed, with registration at the anterior cranial base. This superimposition process took 10-15s. The fit of the cranial base superimposition was verified by qualitative visualization of the semi-transparent axial, sagittal, and coronal cross-sectional slices of all corresponding anatomical structures. Virtual 3D surface models of the skull were generated via threshold segmentation, and superimposition errors in the reoriented models and the results of treatment for the treated cases were evaluated by 3D surface distances on colour-coded maps. The superimposition error of the spatial reorientation and for growing and non-growing patients was <0.5mm, which is acceptable and clinically insignificant. The voxel-based superimposition method evaluated was reproducible in different clinical conditions, rapid, and applicable for research and clinical practice.

[Corneal sensitivity in patients treated medically for glaucoma or ocular hypertension]

PURPOSE

To evaluate the corneal sensitivity in patients treated with intraocular pressure (IOP)-lowering medications.

INTRODUCTION

Chronic administration of anti-glaucoma drops is associated with numerous tissue changes on the ocular surface. The purpose of this study was to investigate the effect of these medications and their preservative, benzalkonium chloride (BAK), on corneal sensitivity.

PATIENTS AND METHODS

Thirty-nine patients treated for glaucoma or ocular hypertension (OHT) and nine untreated patients were included in this study. Treated patients were divided into three groups according to the daily number of preserved eyedrops (0, 1 and ≥2). Corneal sensitivity was assessed using the Cochet-Bonnet esthesiometer. All patients underwent a complete examination of the ocular surface including Schirmer testing, tear film breakup time (BUT) and corneal and conjunctival fluorescein staining. The Ocular Surface Disease Index (OSDI) questionnaire was used to evaluate symptoms.

RESULTS

Corneal sensitivity was 58.8±2.8mm, 56.2±5.2mm, 50.3±12.5mm and 44.3±13.6mm in untreated patients, in patients treated with none, one and two or more instillations of preserved eyedrops, respectively. Corneal sensitivity in patients treated with preserved eyedrops was significantly lower as compared to untreated patients (P<0.001) and patients treated with preservative-free eyedrops (P=0.012). Corneal sensitivity of patients treated with intraocular pressure-lowering medications was negatively correlated to the number of instillations of preserved eyedrops (r=-0.390 ; P<0.001) as well as to the duration of treatment (R=-0.357 ; P=0.001). BUT and fluorescein staining were significantly altered in treated patients compared to the untreated control group ; however, no significant difference was observed between the treated groups. There was no significant difference for OSDI or Schirmer testing between the various groups.

CONCLUSION

Chronic administration of BAK-containing anti-glaucoma eyedrops appears to alter corneal sensitivity. These results could explain the absence of correlation between clinical signs and symptoms sometimes observed in patients treated for glaucoma or OHT.

Effectiveness of low-temperature domestic laundry on the decontamination of healthcare workers' uniforms

OBJECTIVE

Most professionals in the healthcare environment wear uniforms. For the purpose of this study, we concentrated on nurses' uniforms. In the United Kingdom, many nurses are expected to launder their uniforms at home by using a domestic washing machine that frequently has low-temperature wash cycles. We have investigated whether the use of low-temperature wash cycles results in a microbiologically acceptable product to wear on the wards.

METHODS

We have assessed the bioburden on uniforms before and after laundry and the effectiveness of low-temperature wash cycles and ironing on removal of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii. We did not assess the role of tumble drying.

RESULTS

We demonstrate contamination of uniforms by gram-negative bacteria after wash, the removal of MRSA at low-temperature wash cycles in the presence of detergent, and the eradication of gram-negative bacteria after ironing.

CONCLUSIONS

Our conclusions are that laundry in a domestic situation at 60°C (140°F) for 10 minutes is sufficient to decontaminate hospital uniforms and reduces the bacterial load by more than 7-log reduction, that items left in the pockets are decontaminated to the same extent, that the addition of either a biological detergent or a nonbiological detergent is beneficial in removing MRSA from experimentally contaminated swatches, and that uniforms become recontaminated with low numbers of principally gram-negative bacteria after laundry but that these are effectively removed by ironing.

Epithelial or mesenchymal: Where to draw the line?

Epithelial and mesenchymal cells represent two of the main differentiated cell types in all vertebrates. However, their distinction is not always absolutely clear. Dozens of molecules have been used as markers for each cell type, while emerging evidence questions their validity. The aim of this study was to compare the molecular phenotype of these two cell types. Twenty-two commonly used molecular markers were evaluated by quantitative PCR and immunofluorescence in six lines of human and rat epithelial cells and fibroblasts. The epithelial cells were also examined for their responses to TGFbeta1 stimulation. All of the "markers" tested were found in both epithelial and mesenchymal cells. Some epithelial markers, such as CLDN5, OCLN, DSG1 and TJP1, were expressed even higher in fibroblasts than in epithelial cells. In comparison, mesenchymal markers showed more fidelity, but CDH2 and MMP9 were still significantly higher in epithelial cells than in mesenchymal cells. Furthermore, TGFbeta1 up-regulated epithelial markers CTNNB1 and CTNND1, but suppressed mesenchymal markers, such as S100A4, FGF1 and FGF2. In conclusion, no gene expression is cell-type restricted. Although some of these "markers" are expressed more in one cell type than in the other or differently localized, none of them shows a consistent pattern across species to make them universal markers. Nonetheless, some molecules appear to be better markers than others for a specific cell type. The information provided here is expected to serve as a reference for both basic and clinical researchers in the fields of epithelial-mesenchymal transition, molecular cell typing and cancer diagnosis.

Distinguishing nonalcoholic steatohepatitis from fatty liver: serum-free fatty acids, insulin resistance, and serum lipoproteins

OBJECTIVES

The prognosis of nonalcoholic fatty liver disease is determined by liver biopsy; steatohepatitis can be progressive whereas fatty liver is benign. Insulin resistance and increased hepatic-free fatty acids are central to the pathophysiology of this disorder. Our objective was to assess whether serum-free fatty acids, lipoproteins, and insulin resistance are increased in steatohepatitis compared with fatty liver and healthy controls, and thus may be potential noninvasive markers for liver disease severity.

METHODS

Fifteen subjects with biopsy proven nonalcoholic steatohepatitis, 15 with histological fatty liver, and 15 healthy controls were enrolled. Fasting serum glucose and insulin levels, serum-free fatty acids, HDL, LDL, and cholesterol were collected from each subject. Insulin resistance was calculated using the homeostasis assessment model.

RESULTS

Insulin resistance, LDL, and cholesterol-to-HDL ratio values were significantly higher in steatohepatitis, whereas HDL was significantly lower compared with both fatty liver and controls. Free fatty acids were similar in all groups.

CONCLUSIONS

Along with insulin resistance, serum LDL, and cholesterol-to-HDL ratio values increase with worsening severity of liver histology, and serum HDL values decline. Free fatty acids, however, do not vary between groups.

Hildebrand and Hansen solubility parameters from molecular dynamics with applications to electronic nose polymer sensors

We introduce the Cohesive Energy Density (CED) method, a multiple sampling Molecular Dynamics computer simulation procedure that may offer higher consistency in the estimation of Hildebrand and Hansen solubility parameters. The use of a multiple sampling technique, combined with a simple but consistent molecular force field and quantum mechanically determined atomic charges, allows for the precise determination of solubility parameters in a systematic way (sigma = 0.4 hildebrands). The CED method yields first-principles Hildebrand parameter predictions in good agreement with experiment [root-mean-square (rms) = 1.1 hildebrands]. We apply the CED method to model the Caltech electronic nose, an array of 20 polymer sensors. Sensors are built with conducting leads connected through thin-film polymers loaded with carbon black. Odorant detection relies on a change in electric resistivity of the polymer film as function of the amount of swelling caused by the odorant compound. The amount of swelling depends upon the chemical composition of the polymer and the odorant molecule. The pattern is unique, and unambiguously identifies the compound. Experimentally determined changes in relative resistivity of seven polymer sensors upon exposure to 24 solvent vapors were modeled with the CED estimated Hansen solubility components. Predictions of polymer sensor responses result in Pearson R2 coefficients between 0.82 and 0.99.

Arsenite inhibits Ras-dependent activation of ERK but activates ERK in the presence of oncogenic Ras in baboon vascular smooth muscle cells

Exposure to arsenical compounds enhances the risk of atherosclerosis. The reason is unknown but it might be because an effect of arsenite (As3+) on plaque smooth muscle cells (SMCs) activation of extracellular signal-regulated kinase (ERK), a crucial mediator of SMC function. We found that arsenite inhibits the activation of ERK by platelet-derived growth factor-BB (PDGF-BB). This inhibitory effect depends on the time of arsenite exposure, is reversible, and is attenuated by preincubation of SMCs with the antioxidant N-acetyl-cysteine. These observations are consistent with the assumption that oxidative stress is involved. The blockade of ERK by arsenite may be mediated by an inhibition of Ras as arsenite prevents GTP-loading of Ras in response to PDGF-BB. Moreover, the Ras blockade by arsenite is not specific for PDGF-BB because it was also observed following stimulation of SMCs with EGF. To address the role of Ras, we expressed constitutively active, GTP-bound Ha-Ras (V12Ras). Unexpectedly, in V12Ras expressing-SMCs, arsenite stimulates ERK, but still decreases ERK activity in the presence of PDGF-BB. Our data suggest that arsenite inhibits the Ras/ERK pathway in SMCs, and that arsenite may activate ERK in Ras-transformed cells by mechanisms different from those employed by growth factors.

Allele-specific histone acetylation accompanies genomic imprinting of the insulin-like growth factor II receptor gene

The mouse insulin-like growth factor II receptor (Igf2r) gene encodes two reciprocally imprinted RNA transcripts: paternally imprinted Igf2r sense and maternally imprinted Igf2r antisense. Although DNA methylation has been implicated in the initiation and maintenance of genomic imprinting, acetylation of core histones has recently been appreciated as another important factor that regulates gene expression. To determine whether histone acetylation participates in the regulation of Igf2r imprinting, we examined the relative abundance of acetylated histones in interspecific mice (M. spretus x C57BL/6). Oligonucleosomes derived from liver were immunoprecipitated with acetyl-histone antiserum and were analyzed for the allelic distribution of DNA from the region of the sense and antisense Igf2r promoters. In nucleosomes associated with the Igf2r sense promoter, histone acetylation was demonstrated on the maternal allele, which is transcriptionally active. There was much less histone acetylation on the suppressed paternal allele. In nucleosomes associated with the Igf2r antisense promoter, the active paternal allele was heavily acetylated, whereas the suppressed maternal allele was underacetylated. Treatment of cultured fibroblasts with the histone deacetylase inhibitor Trichostatin A induces partial relaxation of genomic imprinting as well as decreased DNA methylation of both Igf2r sense and antisense promoters. These results demonstrate that increases in histone acetylation can lead to decreased DNA methylation, thereby modulating the regulation of the imprinted expression of Igf2r sense and antisense transcripts.

The effect of dehydroepiandrosterone on Zucker rats selected for fat food preference

When allowed to select between macronutrients in a 1-h-a-day meal paradigm, Zucker rats consume 20-80% of their total caloric intake as fat. If they receive an intraperitoneal injection of DHEA 2 h before such a test meal, they consume fewer total calories. The magnitude of this effect on each macronutrient depends upon the animal's initial preference for fat; the higher the initial fat preference, the more profound is the decrease in caloric intake and the more pronounced the effect on fat consumption. Doses as low as 25 mg DHEA/kg body weight are effective. Lean Zucker rats that prefer to consume a high-fat diet have higher epinephrine and dopamine levels in select regions of the hypothalamus known to control food intake. Administration of DHEA to such animals 2 h before decapitation reduces the content of norepinephrine and these monoamines to levels that mimic the values found in the low-fat-preferring animals. It is hypothesized that exogenous DHEA causes the acute release of norepinephrine, epinephrine, and dopamine in select regions of the hypothalamus, and this release causes a decrease in food intake, particularly fat.

Allelic expression of the putative tumor suppressor gene p73 in human fetal tissues and tumor specimens

p73, a proposed tumor suppressor, shares significant amino acid sequence homology with p53. However, p73 is rarely mutated in tumors but it has been suggested that p73 is monoallelically expressed in some tissues. This latter feature would predispose p73 to gene inactivation because a single genetic 'hit' or the loss of the expressed parental allele would leave the cell without p73 activity. We examined the allelic expression of p73 in normal fetal tissues and in ovarian cancer and Wilms' tumor. We found that p73 was biallelically expressed in all fetal tissues, except in brain, where differential expression of the two parental alleles was observed. Biallelic expression of p73 was also observed in paired samples of ovary cancer and Wilms' tumor. Loss of heterozygosity of p73 occurred at relatively low rates in tumors: one of 11 informative samples (9.1%) of ovarian cancer and two of 19 (10.1%) Wilms' tumors. These data demonstrate that p73 is biallelically expressed in most tissues, thus excluding genomic imprinting as a molecular mechanism to predispose to allelic inactivation of p73 in human tumors.

-Cerebral air embolism after removal of an internal jugular vein catheter-

Central venous catheters are usually inserted and manipulated by anaesthetists-intensivists and others familiar with their use under surgical conditions, yet they are often removed on the wards by junior doctors or nurses insufficiently trained in the removal procedure. In order to illustrate the risks presented by such a practice, we report a case of cerebral air embolism following the withdrawal of an internal jugular catheter in a sitting patient. The mechanisms of air entry into the venous and systemic circulation are considered, as well as the preventive and therapeutic measures.

A discrete map for the dynamics of recurrent excitatory neural networks in the presence of noise

We investigate the effect of the neuron characteristics on the behavior of a recurrent excitatory neural network model. First, we present the different types of dynamics obtained with simulations of a network of coupled excitatory spike-response neuron models placed under the influence of noise. Then, we derive a discrete map describing the dynamics of large fully connected networks. By studying the bifurcation structure of this map, we can determine for which ranges of the neuron model parameters the network will display collective oscillations or other types of dynamics.

Effects of transmission delays and noise in recurrent excitatory neural networks

Random perturbations, referred to as noise, are omnipresent in the nervous system. We investigate how noise modifies the dynamics of the neural networks according to the delay. In this report, we examine the effect of transmission delay on both the dynamics of a single neuron receiving a recurrent excitation and the dynamics of fully interconnected excitatory networks. In the case of the single neuron with a recurrent connection, depending on the value of the delay, the discharge pattern changes from regular to multiplets. More complicated patterns appears when noise is added, and depends on both the delay and the noise intensity, but classification can be described. In certain conditions, noise reduces the synchronization, whereas in others it increases the regularity of the network activity. Finally, the same network codes the input amplitude either using mean activity amplitude coding when short delays exist, and using frequency modulation when long delays exist.

Heterotopic ossification after total knee arthroplasty

Heterotopic ossification (HO) is a rare complication following total knee arthroplasty (TKA). In the case report presented, a 52-year-old man who had previously undergone TKA for osteoarthritis noticed painful limitation of range of motion (ROM) in spite of active participation in physical therapy and the use of a continuous passive motion machine. A plain radiograph 1 month after surgery revealed HO anterior to the distal femoral shaft in the quadriceps expansion. Ambulation for this patient was limited to short distances because of severe pain and limitation in ROM. The patient underwent manipulation under general anesthesia 2 months after the TKA. Range of motion in flexion improved from 50 degrees to 110 degrees, and the patient became ambulatory without assistive devices. However, the flexion range deteriorated to 50 degrees over a period of 4 months, and ambulation again became significantly limited. The patient underwent resection of HO 6 months after manipulation and regained his ROM to 110 degrees in flexion. He was prescribed indomethacin after surgery for 2 months to prevent recurrence of HO. Follow-up radiographs 3 months after surgery revealed minimal recurrence of HO. The patient's ROM did not deteriorate, and he remained ambulatory. Heterotopic ossification should be suspected in post-TKA patients if ROM does not improve. Physical therapy including ROM exercises remains an essential component in the treatment of HO. Manipulation under general anesthesia or surgical resection of HO may be inevitable in certain patients whose ambulation is significantly limited.

Changes in serum sterols of rats treated with 7-dehydrocholesterol-delta 7-reductase inhibitors: comparison to levels in humans with Smith-Lemli-Opitz syndrome

The impaired conversion of 7-dehydrocholesterol to cholesterol, as a result of a permanent inhibition of the activity of 7-dehydrocholesterol-delta 7-reductase, has been reported in the Smith-Lemli-Opitz (SLO) syndrome (1, 2). For the purpose of experimental teratology, an animal disease model consisting of the offspring of pregnant rats treated with AY 9944 or BM 15766, inhibitors of 7-dehydrocholesterol-delta 7-reductase, was established. The present study compares the profiles of sterols in rat serum, obtained after transient treatment with inhibitors, with profiles of sterols obtained from patients with the permanent enzyme defect. AY 9944 (single dose of 50, 75, or 100 mg/kg) or BM 15766 (60, 75, or 90 mg/kg per day for 11 days) induces hypocholesterolemia and accumulation of 7-dehydrocholesterol and aberrant sterols in rat serum. The aberrant sterols in the treated rats are similar to those detected in human SLO patients by gas chromatography coupled to mass spectrometry (1, 3, 4) and were identified as 7- and 8-dehydrocholesterol, two trienols (I and II), and 19-nor-5,7,9(10)-cholestatrien-3 beta-ol. The time- and dose-dependences of the biochemical alterations are compared to the teratogenic abnormalities induced by inhibitors. The dietary cholesterol supplementation that suppresses embryo malformations induced by AY 9944 prevents severe hypocholesterolemia and decreases the aberrant sterol levels. As a function of time after intoxication, the 8-dehydrocholesterol to 7-dehydrocholesterol ratio increases, suggested that 8-dehydrocholesterol is derived from the gradual conversion of the accumulated 7-dehydrocholesterol. The ratio of 8-dehydrocholesterol to 7-dehydrocholesterol is higher in human SLO than in the animal disease model. This may be explained by a permanent block in 7-dehydrocholesterol-delta 7-reductase in SLO compared to a transient inhibition of this enzyme in the animal model.

[Syndrome of ovarian hyperstimulation. Report of a severe iatrogenic complication]

Severe ovarian hyperstimulation syndrome is a rare complication of ovulation induction with exogenous gonadotrophins. Severe forms involve acute renal failure, coagulation disorders, massive ascites, pleural effusion and may require pleural and peritoneal puncture. We report a case of severe ovarian hyperstimulation syndrome effectively treated by simple procedures in an intensive care unit.

Operation of an optoelectronic AlGaAs/GaAs waveguide neuron

A novel monolithic AlGaAs/GaAs waveguide neuron is proposed and implemented with a Wannier-Stark superlattice in the core. Dynamic weighting, summing, and thresholding of signals is done by chip-level integration of modulators and a saturable absorber on a rib waveguide power combiner. At 780 nm (below the band gap) the range for synaptic weights is between 1 and -25 dB/mm for reverse bias below 7 V, and the modulation depth is 25 dB for the thresholding element. For a two-to-one neuron, the output-input range ratio is 25 dB.

Traumatic versus postischemic induction of oxidative stress in rat liver

A series of experiments was performed to characterize the effects of tissue trauma, extracellular calcium concentration, and prior ischemia on oxidative stress, measured by the accumulation of malondialdehyde-like materials (MDA-LM) in slices of rat liver. Liver tissue was rendered ischemic for 1 hour at 37 degrees C, either minced (to create traumatized fragments) or cleanly cut and washed (to create nontraumatized fragments), and then reoxygenated for 30 minutes in flasks of buffered salt solution. Nonischemic tissue was incubated similarly but without the 60-minute prior ischemia. The production of MDA-LM in the tissues was used as an indicator of lipid peroxidation. Production of MDA-LM in the tissues was used as an indicator of lipid peroxidation. Production of MDA-LM was always enhanced by prior ischemia and reoxygenation. However, trauma also increased the production of MDA-LM both in nonischemic liver slices in vitro and in those subjected to ischemia and reoxygenation. Furthermore, the elimination of calcium from incubation buffer significantly reduced MDA-LM production both in nontraumatized, ischemic, and reoxygenated tissues and in traumatized, nonischemic tissues; while the addition of the calcium ionophore A23187 (10 mumol/L) increased MDA-LM production in nontraumatized tissues independently of ischemia and reoxygenation. In nonischemic, traumatized tissues, the iron chelators deferoxamine and CGP-46,700A (1,2-diethyl-3-hydroxypyrid-4-one) quenched MDA-LM production. These data indicate that either ischemia or mechanical trauma may predispose liver tissue to calcium-dependent and iron-dependent oxidative stress.

Potential use of simple manganese salts as antioxidant drugs in horses

The scavenging of superoxide radicals by endogenous and therapeutically administered superoxide dismutases may prevent superoxide-mediated oxidative stress leading to lipid peroxidation, membrane lysis, and cell death in a wide variety of normal and pathologic states. Simple inorganic manganous salts such as MnCl2 also have superoxide dismutase-like activity and are extremely inexpensive, compared with enzymatic superoxide dismutase preparations. In this study, we explored the use of Mn salts as antioxidant drugs. We used the percentage of inhibition of nitroblue tetrazolium reduction by superoxide as a measure of the amount of superoxide dismutase-like activity. We found concentration-related increases in superoxide scavenging activity in simple buffer solutions upon addition of 1.25, 2.5, and 5.0 microM MnSO4. To determine whether Mn salts can inhibit oxidative damage in tissues, we used an in vitro model of lipid peroxidation in ischemic and reoxygenated rat liver slices. Concentrations of 10, 100, and 1000 mumoles MnCl2/L of buffer significantly decreased indicators of lipid peroxidation believed to be initiated by intracellular superoxide. We then determined the effectiveness of MnCl2 as a superoxide scavenger in conscious horses by measuring the superoxide scavenging ability of equine plasma before and during intravenous infusions of 1.0 L volumes of 0.9% saline solution containing 0, 12.5, or 25 mM MnCl2. Plasma Mn concentrations, which were determined by atomic absorption spectrophotometry, increased as a function of time and dose. Intravenously administered MnCl2 concomitantly produced dose-related increases in superoxide scavenging ability of equine plasma at 15, 30, 45, and 60 minutes after the onset of infusion, compared with preinfusion control values.(ABSTRACT TRUNCATED AT 250 WORDS)

Mandibular infected buccal cyst: report of two cases

Two cases of mandibular infected buccal cyst are presented. A thorough review of the literature reveals that this is a fairly new entity with the first cases reported by Stoneman and Worth in 1983.

Usefulness of selectively ordered preoperative tests

The authors prospectively evaluated the usefulness of 12 preoperative tests (including blood type and screen) ordered selectively according to clinical status and importance of scheduled surgery. Two methods of assessing usefulness of tests were used, taking into account not simply their abnormality yield, but also their impact on patient care during the entire hospitalization: first, usefulness was assessed by anesthetists involved in care; second, usefulness was assessed by an automated analysis of specific clinical situations in which tests were a priori considered useful. In 3,866 patients 15,920 tests were performed; 30% of performed tests were abnormal. As a consequence of test results, surgery was delayed or cancelled in 19 patients and modified in 1, and a treatment was instituted or anesthetic management influenced in 347 (9%). Blood component therapy was instituted in 652 patients (17%). Anesthetists and automated analysis found at least one preoperative test useful in 931 patients (24%) and 890 patients (23%), respectively, whereas on a per-test basis 17% and 9% of tests were found useful. The discrepancy in usefulness assessment was mainly due to differences in evaluation of the usefulness of normal results. This study shows that the usefulness of selectively ordered preoperative tests may be high, but better criteria for their indications are needed, because tests other than those recommended by protocol were found useful.

[Evaluation of a protocol for selective ordering of preoperative tests in healthy subjects]

A protocol for selective ordering of 12 preoperative tests was prospectively evaluated during one year in a teaching hospital. 1600 consecutive healthy patients had an average of 2.4 tests each, but 270 of them had none. Usefulness of tests was assessed by taking into account not simply their abnormality yield, but also their impact on patient care during the whole hospital stay in the anaesthetist view. The possible value of tests omitted was assessed by anaesthetists at the end of hospital stay. As a consequence of test results, surgery was delayed in one patient, and a treatment was started or the anaesthetic management adapted in 16.7% of tests performed (279/3905) were found to be useful and 0.1% of tests not carried out (21/15295) would have been potentially useful. No complication inducing sequelae or death could be linked to tests not carried out. This study showed that routine preoperative investigations in healthy patients could be avoided without any adverse effects on patient care.

The value of early fibreoptic bronchoscopy after aspiration of gastric contents

Fibreoptic bronchoscopy was undertaken in 26 patients upon hospital admission, to assess if they were suffering from pulmonary lesions subsequent to the aspiration of gastric contents. In 24 of these patients erythematous lesions were observed (sensitivity of the procedure: 92.3%), mainly on the carina. Distal to the carina, the lesions were observed less frequently. The procedure caused no complications in any of the patients studied.

[Inhalation pneumonia in toxic comas. Apropos of 200 cases with 4 deaths]

In 1946, Mendelson described 66 cases of gastric juice inhalation during obstetrical work with no mortality. Other studies studying different populations (essentially in post-operative condition) denounced a mortality from 19 to 64%. In Forensic Medicine, a bronchial regurgitation of gastric juice is denounced in 1/3 lethal toxic comas. This regurgitation can be the direct cause of the death, it also can be an epiphenomena, as suggests the high level of inhalation in agonic process of any cause: 1/4 of autopsy findings. In our department, 200 cases of inhalation pneumonia, during comatose intoxications have been registered between 1972-1982, with a frequency of 1/28 patients. All the patients were under assisted ventilation. 4 deaths occurred in this serie. This 2% mortality suggests the curability of gastric juice inhalation during comatose intoxications in not specifically respiratory-orientated intensive Care Units. These relatively good results are probably party related to the patients' recruitment: young population without underlying organic disease, with a rapid turnover and little hazards of nosocomial superinfections.

[Hypo-oxygenation in paraquat poisoning. Apropos of 6 cases]

The toxicity of the weed-killer paraquat is related to the formation of superoxyde radicals responsible of a progressive and usually lethal pulmonary fibrosis. Recognition of lipid peroxidation of membrane bilayers by free radicals as the causative factor pointed to oxygen as an important cofactor in the severity of paraquat poisoning. It has been shown that any FiO2 over 21% accelerates this process and increases the the mortality of rats and humans. FiO2 21% gave a significant reduction of mortality in rats (DOUZE 1976). We proposed this therapy (1978-1879) in 6 cases of paraquat poisoning. It was conducted with induction of a barbiturate coma, hypothermia, curarisation and hypo-oxygenation (FiO2 around 14% thanks to the adjunction of nitrogen to assisted ventilation). In 5/6 patients, these technics did not prevent the evolution towards death. This evolution was in fact predicted, according the following prognostic factors: suicide, more than a mouthful ingestion, oesophago-gastric burns detected by endoscopy, organic renal failure, high plasma paraquat level. Associated methods of elimination (Fuller's earth, provoked diarrhea, furosemide, hemoperfusion and hemodialysis) did not change the early established prognosis. The only survival was observed in an accidental poisoning with undetectable plasma paraquat and isolated oral burns: the herbicide had been probably spit out. This survival cannot be related to hypo-oxygenation. This failure is not definitive, according to us: this therapy should be undertaken only after minimal, accidental poisoning possibly evolving to pulmonary fibrosis. It appears unuseful in massive, suicidal poisonings, leading readily to a lethal circulatory failure.