A modeling approach to understanding OLED performance improvements arising from spatial variations in guest:host blend ratio.

Phosphorescent organic light emitting diodes (OLEDs) suffer from efficiency roll off, where device efficiency rapidly decays at higher luminance. One strategy to minimize this loss of efficiency at higher luminance is the use of non-uniform or graded guest:host blend ratios within the emissive layer. This work applies a multi-scale modeling framework to elucidate the mechanisms by which a non-uniform blend ratio can change the performance of an OLED. Mobility and exciton data are extracted from a kinetic Monte-Carlo model, which is then coupled to a drift diffusion model for fast sampling of the parameter space. The model is applied to OLEDs with uniform, linear, and stepwise graduations in the blend ratio in the emissive layer. The distribution of the guests in the film was found to affect the mobility of the charge carriers, and it was determined that having a graduated guest profile broadened the recombination zone, leading to a reduction in second order annihilation rates. That is, there was a reduction in triplet-triplet and triplet-polaron annihilation. Reducing triplet-triplet and triplet-polaron annihilation would lead to an improvement in device efficiency.

Sensory experience regulates cortical inhibition by inducing IGF1 in VIP neurons.

Inhibitory neurons regulate the adaptation of neural circuits to sensory experience, but the molecular mechanisms by which experience controls the connectivity between different types of inhibitory neuron to regulate cortical plasticity are largely unknown. Here we show that exposure of dark-housed mice to light induces a gene program in cortical vasoactive intestinal peptide (VIP)-expressing neurons that is markedly distinct from that induced in excitatory neurons and other subtypes of inhibitory neuron. We identify Igf1 as one of several activity-regulated genes that are specific to VIP neurons, and demonstrate that IGF1 functions cell-autonomously in VIP neurons to increase inhibitory synaptic input onto these neurons. Our findings further suggest that in cortical VIP neurons, experience-dependent gene transcription regulates visual acuity by activating the expression of IGF1, thus promoting the inhibition of disinhibitory neurons and affecting inhibition onto cortical pyramidal neurons.

Exposure to traffic-related air pollution and changes in exhaled nitric oxide and DNA methylation in arginase and nitric oxide synthase in children with asthma.

BACKGROUND: Traffic-related air pollution (TRAP) has been associated with increased risk of airway inflammation in children with asthma. While epigenetic changes could potentially modulate TRAP-induced inflammatory responses, few studies have assessed the temporal pattern of exposure to TRAP, epigenetic changes and inflammation in children with asthma. Our goal was to test the time-lag patterns of personal exposure to TRAP, airway inflammation (measured as fractional exhaled nitric oxide, FeNO), and DNA methylation in the promoter regions of genes involved in nitric oxide synthesis among children with asthma. METHODS: We measured personal exposure to black carbon (BC) and FeNO for up to 30 days in a panel of children with asthma. We collected 90 buccal cell samples for DNA methylation analysis from 18 children (5 per child). Methylation in promoter regions of nitric oxide synthase (NOS1, NOS2A, NOS3) and arginase (ARG1, ARG2) was assessed by bisulfite pyrosequencing. Linear-mixed effect models were used to test the associations of BC at different lag periods, percent DNA methylation at each site and FeNO level. RESULTS: Exposure to BC was positively associated with FeNO, and negatively associated with DNA methylation in NOS3. We found strongest association between FeNO and BC at lag 0-6 h while strongest associations between methylation at positions 1 and 2 in NOS3 and BC were at lag 13-24 h and lag 0-24 h, respectively. The strengths of associations were attenuated at longer lag periods. No significant associations between exposure to TRAP and methylation levels in other NOS and ARG isoforms were observed. CONCLUSIONS: Exposure to TRAP was associated with higher levels of FeNO and lower levels of DNA methylation in the promoter regions of the NOS3 gene, indicating that DNA methylation of the NOS3 gene could be an important epigenetic mechanism in physiological responses to TRAP in children with asthma.

A dual role for the RhoGEF Ephexin5 in regulation of dendritic spine outgrowth.

The outgrowth of new dendritic spines is closely linked to the formation of new synapses, and is thought to be a vital component of the experience-dependent circuit plasticity that supports learning. Here, we examined the role of the RhoGEF Ephexin5 in driving activity-dependent spine outgrowth. We found that reducing Ephexin5 levels increased spine outgrowth, and increasing Ephexin5 levels decreased spine outgrowth in a GEF-dependent manner, suggesting that Ephexin5 acts as an inhibitor of spine outgrowth. Notably, we found that increased neural activity led to a proteasome-dependent reduction in the levels of Ephexin5 in neuronal dendrites, which could facilitate the enhanced spine outgrowth observed following increased neural activity. Surprisingly, we also found that Ephexin5-GFP levels were elevated on the dendrite at sites of future new spines, prior to new spine outgrowth. Moreover, lowering neuronal Ephexin5 levels inhibited new spine outgrowth in response to both global increases in neural activity and local glutamatergic stimulation of the dendrite, suggesting that Ephexin5 is necessary for activity-dependent spine outgrowth. Our data support a model in which Ephexin5 serves a dual role in spinogenesis, acting both as a brake on overall spine outgrowth and as a necessary component in the site-specific formation of new spines.

A lethal model of disseminated dengue virus type 1 infection in AG129 mice.

The mosquito-borne disease dengue is caused by four serologically and genetically related flaviviruses termed DENV-1 to DENV-4. Dengue is a global public health concern, with both the geographical range and burden of disease increasing rapidly. Clinically, dengue ranges from a relatively mild self-limiting illness to a severe life-threatening and sometimes fatal disease. Infection with one DENV serotype produces life-long homotypic immunity, but incomplete and short-term heterotypic protection. The development of small-animal models that recapitulate the characteristics of the disseminated disease seen clinically has been difficult, slowing the development of vaccines and therapeutics. The AG129 mouse (deficient in interferon alpha/beta and gamma receptor signalling) has proven to be valuable for this purpose, with the development of models of disseminated DENV-2,-3 and -4 disease. Recently, a DENV-1 AG129 model was described, but it requires antibody-dependent enhancement (ADE) to produce lethality. Here we describe a new AG129 model utilizing a non-mouse-adapted DENV-1 strain, West Pacific 74, that does not require ADE to induce lethal disease. Following high-titre intraperitoneal challenge, animals experience a virus infection with dissemination to multiple visceral tissues, including the liver, spleen and intestine. The animals also become thrombocytopenic, but vascular leakage is less prominent than in AG129 models with other DENV serotypes. Taken together, our studies demonstrate that this model is an important addition to dengue research, particularly for understanding the pathological basis of the disease between DENV serotypes and allowing the full spectrum of activity to test comparisons for putative vaccines and antivirals.

PROSPER delivery of universal preventive interventions with young adolescents: long-term effects on emerging adult substance misuse and associated risk behaviors.

BACKGROUND: Substance misuse and associated health-risking behaviors are prevalent in emerging adulthood. There is a knowledge gap concerning the post-high school effects of community-based delivery systems for universal preventive interventions implemented during young adolescence. This study reports effects of the PROSPER delivery system through age 19, 7.5 years past baseline. METHODS: A cohort sequential design included 28 public school districts randomly assigned to the PROSPER partnership delivery system or usual-programming conditions. PROSPER community teams implemented a family-focused intervention in 6th grade and a school-based intervention in 7th grade. Outcomes for the age 19, post-high school report included lifetime, current, and frequency of substance misuse, as well as antisocial and health-risking sexual behaviors. Intent-to-treat, multi-level analyses of covariance of point-in-time outcomes were conducted, along with analyses of risk-related moderation of intervention effects. RESULTS: Results showed emerging adults from PROSPER communities reported significantly lower substance misuse across a range of types of substances, with relative reduction rates of up to 41.0%. No significant findings were observed for associated antisocial and health-risking sexual behavior indices; or for lifetime rates of sexually transmitted infections. Risk-related moderation effects were non-significant, suggesting generally comparable outcomes across higher- and lower-risk subgroups of emerging adults. CONCLUSIONS: The PROSPER delivery system for brief universal preventive interventions has potential for public health impact by reducing long-term substance misuse, with positive results extending beyond high school.

Report on World Workshops on Oral Medicine (WWOM) IV and V: research themes and citation impact: WWOM VI steering committee.

The first World Workshop on Oral Medicine (WWOM) was held in 1988. The portfolio has continued to expand in scope and impact over the past 26 years. Five World Workshops were conducted between 1988 and 2010, focusing on creation of systematic reviews in biomedicine and health care of importance to the international oral medicine community. WWOM VI was conducted in April 2014 and further extended this modeling. This most recent Workshop also fostered creation of the inaugural joint meeting between the American Academy of Oral Medicine and the European Association of Oral Medicine, together with The British Society for Oral Medicine and the Oral Medicine Academy of Australasia. The goal of the WWOM portfolio is to strategically enhance international oral medicine research, education, and clinical practice. To this end, this report summarizes subject areas for WWOM IV (2004) and research recommendations for WWOM V (2010), as well as citation metrics relative to publications from these two conferences. The information is designed to provide research and clinical context for key issues in oral medicine as delineated by the WWOM portfolio over the past 10 years, as well as for projected outcomes of WWOM VI over the next 12 months.

Risk of herpes zoster among diabetics: a matched cohort study in a US insurance claim database before introduction of vaccination, 1997-2006.

PURPOSE: To assess whether diabetes is a risk factor for herpes zoster (HZ). METHODS: We conducted a retrospective cohort study using the Integrated Health Care Information Services database, during the period 1997-2006. A type I diabetes cohort, a type II diabetes cohort and two non-diabetic cohorts matched for date of enrolment and duration of follow-up were defined. HZ and diabetes were defined using a combination of ICD-9 and prescription drug codes. Individuals with immunosuppressive conditions or treatments were excluded. Cox Proportional Hazards regression analysis using a stepwise method with backward elimination was applied to estimate the hazard ratios (HR) of HZ, including age, gender and co-morbidities as covariates. RESULTS: The study population comprised 380,401 and 20,397 type II and type I diabetic subjects respectively, as well as 1,521,604 and 81,588 matched controls. The median ages were 55, 35, 33 and 29 years, respectively. HZ incidence was 4.59, 2.13, 1.97, and 1.82 per 1,000 person-years, respectively. There was no evidence of an impact of type I diabetes on the risk of HZ. Type II diabetes was associated with an increased risk for HZ in subjects ≥ 65 (HR 3.12; 95 % CI 2.77-3.52, adjusted for gender) and in subjects between 40 and 64 (HR 1.51; 95 % CI 1.42-1.61) years of age. Cardiac disease and chronic pulmonary disease were also risk factors (HR 1.92; 95 % CI 1.73-2.13 and HR 1.52; 95 % CI 1.38-1.67) in non-diabetic subjects. CONCLUSIONS: This study suggests that type II diabetes is associated with an increased risk of developing HZ, which was particularly high in adults 65 years and older and moderately increased in adults under 65 years of age.

Dehydrated human amnion/chorion membrane for the treatment of severe skin and tissue loss in an preterm infant: a case report.

Extreme prematurity complicated with severe congenital cutaneous candidiasis (CCC) is rare and clinically challenging. We present the case of a 615g dizygotic twin delivered at 24 weeks gestation with congenital candidiasis, who developed severe skin and tissue loss, successfully treated with dehydrated human amnion/chorion membrane (dHACM). The infant had a complicated medical course, including treatment for patent ductus arteriosus (PDA), necrotising enterocolitis (NEC), and neonatal abstinence syndrome (NAS). In the operating room after debridement, dHACM was placed over all abdominal and back areas of skin loss and covered with a non-occlusive, non-adherent silver dressing. This dressing regimen was chosen in an effort to provide not only topical antimicrobial coverage, but also to maintain a non-shear, moist wound healing environment, which was so important in the dry incubator environment of the neonatal intensive care centre. Over the next four weeks, the baby was medically managed, and the wounds healed on their own with only weekly bedside dressing changes. This case report provides the first example of successful complex management of extensive life-threatening wounds in a premature infant using dHACM.

Traffic-related air pollution, chronic stress, and changes in exhaled nitric oxide and lung function among a panel of children with asthma living in an underresourced community.

We examined associations between short-term exposure to traffic-related air pollutants (TRAP) and airway inflammation and lung function in children with asthma, and whether these associations are modified by chronic psychological stress. Residents of underresourced port-adjacent communities in New Jersey were concerned about the cumulative impacts of exposure to TRAP, particularly diesel-engine truck emissions, and stress on exacerbation of asthma among children. Children with asthma aged 9-14 (n = 35) were recruited from non-smoking households. We measured each participant's (1) continuous personal exposure to black carbon (BC, a surrogate of TRAP) at 1-min intervals, (2) 24-h integrated personal exposure to nitrogen dioxide (NO2), (3) daily fractional exhaled nitric oxide (FeNO), and (4) lung function for up to 30 consecutive days. Personal BC was recorded by micro-aethalometers. We measured daily FeNO using the NIOX MINO, forced expiratory volume in one second (FEV1), and forced vital capacity (FVC) using Easy One Frontline spirometers. Chronic stress was measured with the UCLA Life Stress Interview for Children. The association was examined using linear mixed-effect models. In the fully adjusted model, an interquartile range (IQR) increase in BC at lag 0-6 h before the FeNO measurement was associated with 8 % (95 % CI: 3 % - 12 %) increase in FeNO, whereas an IQR increase in BC at lag 7-12 h and lag 0-24 h were associated with 6 % (95 % CI: 2 % - 11 %) and 7 % (2 % - 12 %) FeNO increases, respectively. There were no significant lung function changes per IQR increase in BC. No interactions were observed between chronic stress and BC on FeNO. Chronic stress was negatively associated with individual average FeNO levels. Our findings suggest that higher levels of BC exposure within the prior 24 h increased airway inflammation levels in children with asthma, with the strongest effect observed within the first 6 h.

Progressive amnestic dementia, hippocampal sclerosis, and mutation in C9ORF72.

The most common cause of familial frontotemporal lobar degeneration with TAR DNA-binding protein-43 pathology (FTLD-TDP) has been found to be an expansion of a hexanucleotide repeat (GGGGCC) in a noncoding region of the gene C9ORF72. Hippocampal sclerosis (HpScl) is a common finding in FTLD-TDP. Our objective was to screen for the presence of C9ORF72 hexanucleotide repeat expansions in a pathologically confirmed cohort of "pure" hippocampal sclerosis cases (n = 33), outside the setting of FTLD-TDP and Alzheimer's disease (AD). Using a recently described repeat-associated non-ATG (RAN) translation (C9RANT) antibody that was found to be highly specific for c9FTD/ALS, we identified a single "pure" HpScl autopsy case with a repeat expansion in C9ORF72 (c9HpScl). Mutation screening was also performed with repeat-primed polymerase chain reaction and further confirmed with Southern blotting. The c9HpScl patient had a 14-year history of a slowly progressive amnestic syndrome and a clinical diagnosis of probable AD. Neuropsychological testing revealed memory impairment, but no deficits in other cognitive domains. Autopsy showed hippocampal sclerosis with TDP-43 immunoreactive neuronal inclusions relatively limited to limbic lobe structures. Neuritic pathology immunoreactive for p62 was more frequent than TDP-43 in amygdala and hippocampus. Frequent p62-positive neuronal inclusions were present in cerebellar granule neurons as is typical of C9ORF72 mutation carriers. There was no significant FTLD or motor neuron disease. C9RANT was found to be sensitive and specific in this autopsy-confirmed series of HpScl cases. The findings in this patient suggest that the clinical and pathologic spectrum of C9ORF72 repeat expansion is wider than frontotemporal dementia and motor neuron disease, including cases of progressive amnestic dementia with restricted TDP-43 pathology associated with HpScl.

Optimal frequency of parathyroid hormone monitoring in chronic hemodialysis patients.

BACKGROUND: Secondary hyperparathyroidism is a common manifestation of chronic kidney disease (CKD). Serum parathyroid hormone (PTH) level is widely used as a marker for hyperparathyroidism. Currently, there is limited data to guide the frequency of PTH monitoring in CKD patients. The present study was undertaken to determine the optimal frequency of monitoring PTH in patients on maintenance hemodialysis. METHODS: A cohort of 154 patients on maintenance dialysis at a single outpatient hemodialysis center was included in this retrospective study. In Phase I of the study, PTH was measured every 3 months as per Kidney Disease Outcomes Quality Initiative (KDOQI) recommendations. In Phase II, PTH was measured monthly. In both phases, dietary education and optimization of medications including phosphate binders, vitamin D analogues and calcimimetics were implemented using standard protocols Data from the two phases was compared with each other and with their respective national norms. RESULTS: The percentage of patients with PTH in target range of 150 - 300 pg/ml increased significantly from Phase I to Phase II of the study (25.4 - 40.3%, p < 0.01). There was a significant reduction in the percentage of patients with PTH levels > 300 pg/ml in Phase II compared with national averages (37% vs. 47%, p < 0.02). There was no significant difference in calcium and phosphorus levels or their product. There was a significant increase in the usage of calcimimetics and vitamin D analogues. CONCLUSION: We observed that increasing the frequency of monitoring PTH from quarterly to monthly was associated with a significant increase in the percentage of patients reaching KDOQI target PTH values.

Persistent orofacial muscle pain.

The pathophysiology of persistent orofacial myalgia has been the centre of much controversy. In this article we suggest a novel descriptive term; 'persistent orofacial muscle pain' (POMP) and review current evidence that supports the hypothesis that the induction of POMP involves the interplay between a peripheral nociceptive source in muscle, a faulty central nervous system component and decreased coping ability. In this context it is widely accepted that a complex interaction of variable intrinsic and extrinsic factors act to induce POMP and dysfunction.

Local drug delivery for oral mucosal diseases: challenges and opportunities.

There are few topical formulations used for oral medicine applications most of which have been developed for the management of dermatological conditions. As such, numerous obstacles are faced when utilizing these preparations in the oral cavity, namely enzymatic degradation, taste, limited surface area, poor tissue penetration and accidental swallowing. In this review, we discuss common mucosal diseases such as oral cancer, mucositis, vesiculo-erosive conditions, infections, neuropathic pain and salivary dysfunction, which could benefit from topical delivery systems designed specifically for the oral mucosa, which are capable of sustained release. Each condition requires distinct penetration and drug retention profiles in order to optimize treatment and minimize side effects. Local drug delivery may provide a more targeted and efficient drug-delivery option than systemic delivery for diseases of the oral mucosa. We identify those mucosal diseases currently being treated, the challenges that must be overcome and the potential of novel therapies. Novel biological therapies such as macromolecular biological drugs, peptides and gene therapy may be of value in the treatment of many chronic oral conditions and thus in oral medicine if their delivery can be optimized.

An international survey of oral medicine practice: proceedings from the 5th World Workshop in Oral Medicine.

OBJECTIVES: (i) To define the current state of oral medicine clinical practice internationally, and (ii) to make recommendations for future modeling of the practice of oral medicine. MATERIALS AND METHODS: A survey was designed by an international panel of oral medicine experts to assess the current state of oral medicine practice internationally. The survey was sent to oral medicine experts across the world, and responses were electronically stored and analyzed using descriptive statistics. RESULTS: Two hundred respondents completed the survey representing 40 countries from six continents. The two most common settings for an oral medicine practice were in a hospital and a dental school. More than 88% of respondents considered management of oral mucosal disease, salivary dysfunction, oral manifestations of systemic diseases, and facial pain in the definition of oral medicine. CONCLUSIONS: (i) Oral medicine clinicians diagnose and manage a wide variety of orofacial conditions; (ii) There are significant differences in the definition of oral medicine clinical practice from country to country; (iii) India has the largest expansion of oral medicine services as defined by escalating numbers of clinicians within the specialty as compared with other countries; (iv) oral medicine practitioners have a wide range of professional responsibilities.

Best Practices for Building Interprofessional Telehealth: Report of a Conference.

The Arizona Biomedical Research Centre (ABRC) has funded a series of workshops and conferences since 2016 to build the capacity of local, tribal, and state agencies, healthcare delivery organizations, and non-governmental organizations to engage in meaningful research related to health disparities. With the COVID-19 pandemic, the use of telehealth has dramatically increased, particularly in nursing, occupational therapy (OT), physical therapy (PT), and speech-language pathology (SLP). The purpose of this paper is to summarize the presentations and discussion from the conference titled "Telerehabilitation and Telepractice: An Interprofessional Conference to Build Connections and Best Practices," held remotely on March 4-5, 2021. Terminology and concepts from the conference were debated, modified, and refined, based on an interprofessional audience. Presenters at the conference, all leaders in their field, discussed the current status of telehealth in their professions, including best practices, challenges, future trends, and research needs.

Digital intervention increases influenza vaccination rates for people with diabetes in a decentralized randomized trial.

People with diabetes (PWD) have an increased risk of developing influenza-related complications, including pneumonia, abnormal glycemic events, and hospitalization. Annual influenza vaccination is recommended for PWD, but vaccination rates are suboptimal. The study aimed to increase influenza vaccination rate in people with self-reported diabetes. This study was a prospective, 1:1 randomized controlled trial of a 6-month Digital Diabetes Intervention in U.S. adults with diabetes. The intervention group received monthly messages through an online health platform. The control group received no intervention. Difference in self-reported vaccination rates was tested using multivariable logistic regression controlling for demographics and comorbidities. The study was registered at clinicaltrials.gov: NCT03870997. A total of 10,429 participants reported influenza vaccination status (5158 intervention, mean age (±SD) = 46.8 (11.1), 78.5% female; 5271 control, Mean age (±SD) = 46.7 (11.2), 79.4% female). After a 6-month intervention, 64.2% of the intervention arm reported influenza vaccination, vers us 61.1% in the control arm (diff = 3.1, RR = 1.05, 95% CI [1.02, 1.08], p = 0.0013, number needed to treat = 33 to obtain 1 additional vaccination). Completion of one or more intervention messages was associated with up to an 8% increase in vaccination rate (OR 1.27, 95% CI [1.17, 1.38], p < 0.0001). The intervention improved influenza vaccination rates in PWD, suggesting that leveraging new technology to deliver knowledge and information can improve influenza vaccination rates in high-risk populations to reduce public health burden of influenza. Rapid cycle innovation could maximize the effects of these digital interventions in the future with other populations and vaccines.

Incidence and predictors of treatment-related mortality in paediatric acute leukaemia in El Salvador.

Survival rates among children with leukaemia in low-income countries are lower than those in high-income countries. This has been attributed in part to higher treatment-related mortality (TRM). We examined the demographics, treatment, and outcomes of paediatric patients in El Salvador with acute lymphoblastic leukaemia (ALL) or acute myeloid leukaemia (AML) to determine the incidence, causes, and risk factors for TRM. Two trained data managers collected data prospectively; no patients were excluded. Biological, socioeconomic and nutritional predictors were examined. A total of 469 patients with ALL and 78 patients with AML were included. The 2-year cumulative incidence of TRM was significantly higher among children with AML (35.4+/-6.4%) than those with ALL (12.5+/-1.7%; P<0.0001). However, the proportion of deaths attributable to the toxicity of treatment did not differ significantly between AML (25/47, 53.2%) and ALL (55/107, 51.4%; P=0.98). Among children with ALL, low monthly income (P=0.04) and low parental education (P=0.02) significantly increased the risk of TRM. Among children with AML, biological, socioeconomic, and nutritional variables were not associated with TRM. In this low-income country, toxic death significantly contributes to mortality in both ALL and AML. A better understanding of the effect of socioeconomic status on TRM may suggest specific strategies for patients with ALL.

Phenotypic changes and loss of N-CAM-mediated adhesion in transformed embryonic chicken retinal cells.

Transformation of 6-d-old embryonic chicken retinal cells by Rous sarcoma virus (RSV) was found to cause significant changes in several cellular properties including adhesiveness, motility, and state of differentiation. The alterations in cell adhesivity were analyzed by means of specific antibodies to the calcium-independent neural cell adhesion molecule, N-CAM. In the RSV-transformed cells the amount of N-CAM present at the cell surface was significantly decreased relative to normal cells, as assessed by immunofluorescent staining, specific immunoprecipitation, and immunoblotting experiments. This decrease was reflected in a marked reduction in N-CAM-mediated adhesiveness measured in vitro. A different, calcium-dependent, adhesive system also present on neurons was not detectably altered by RSV transformation and, in contrast with previous studies on normal neurons, this adhesive system was detected without treatment by proteases. In culture, the transformed cells formed fewer and less compact colonies than the normal retinal cells. Observation of the RSV-transformed retinal cells by time-lapse cinematography confirmed the reduction in adhesiveness and also revealed that the transformed cells were more highly motile than their normal counterparts. In addition, RSV transformation appeared to alter the differentiation of the cultured retinal cells. Immunofluorescent staining studies indicated that in contrast to mature neurons, transformed neural retinal cells expressed the 34,000-mol-wt tyrosine kinase substrate and reduced amounts of a neuron-specific ganglioside recognized by monoclonal antibody A2B5. These characteristics are shared by untransformed glial cells. In double immunofluorescent staining experiments, many cells expressed both N-CAM and pp60src shortly after viral infection, which implies that the N-CAM-positive neuroepithelial cells were transformed by RSV. In addition, a highly purified population of N-CAM-positive neural retinal cells, selected using a fluorescence-activated cell sorter, was rapidly and extensively transformed by RSV at rates comparable to those of the unfractionated population. These results established that the transformed cells were largely derived from RSV-infected neuroepithelial cells rather than from a small population of retinal glial cells present in the primary culture. The findings suggest reconsideration of the possible origin of tumors classified by morphological criteria as derived from glia and raise the possibility that the normal homologue of pp60src may play a role in the commitment of neuroepithelial cells to neuronal or glial differentiation pathways.