Patient Education Materials for Immobilisation Masks in Radiation Therapy for Adult Head and Neck Cancer Patients: A Scoping Review

Immobilisation masks (IMs) are used for people with head and neck cancer (HNC) undergoing radiation therapy (RT) treatment to ensure accuracy and reproducibility between treatments. Claustrophobia-related mask anxiety in HNC patients is common and can compromise treatment due to patient distress. This scoping review aimed to describe the content of publicly available Patient Education Materials (PEMs) for people with HNC undergoing RT. Three search engines (Bing, Yahoo, and Google) were systematically searched using standard terms. PEMs in audio-visual or written formats were eligible for inclusion if the target readership was adults with HNC and included content on IMs for RT. Content was appraised using the Patient Education Materials Assessment Tool for Printable and Audio-Visual Materials to assess understandability and actionability. In total, 304 PEMs were identified of which 20 met the inclusion criteria. Sixteen PEMs were webpages, three were PDF format, and one was a standalone video. The understandability and actionability of PEMs ranged between 47 to 100% and 0 to 80%, respectively. PEMs authored by Foundations/Organisations scored higher in understandability (80-100%) and were more likely to discuss mask anxiety coping strategies. In comparison, News sites and IM manufacturers published PEMs with the lowest understandability scores (20-80%). The significant variations in the quality of IM PEMs identified suggest that some sources may be more effective at informing patients about IMs. Although multiple aspects of the PEMs were consistent across the reviewed materials, many PEMs lacked information, and a stronger focus on understandability and actionability is required.

A village in a dish model system for population-scale hiPSC studies

The mechanisms by which DNA alleles contribute to disease risk, drug response, and other human phenotypes are highly context-specific, varying across cell types and different conditions. Human induced pluripotent stem cells are uniquely suited to study these context-dependent effects but cell lines from hundreds or thousands of individuals are required. Village cultures, where multiple induced pluripotent stem lines are cultured and differentiated in a single dish, provide an elegant solution for scaling induced pluripotent stem experiments to the necessary sample sizes required for population-scale studies. Here, we show the utility of village models, demonstrating how cells can be assigned to an induced pluripotent stem line using single-cell sequencing and illustrating that the genetic, epigenetic or induced pluripotent stem line-specific effects explain a large percentage of gene expression variation for many genes. We demonstrate that village methods can effectively detect induced pluripotent stem line-specific effects, including sensitive dynamics of cell states.

Label-free optical imaging of cell function and collagen structure for cell-based therapies

Cell-based therapies harness functional cells or tissues to mediate healing and treat disease. Assessment of cellular therapeutics requires methods that are non-destructive to ensure therapies remain viable and uncontaminated for use in patients. Optical imaging of endogenous collagen, by second-harmonic generation, and the metabolic coenzymes NADH and FAD, by autofluorescence microscopy, provides tissue structure and cellular information. Here, we review applications of label-free nonlinear optical imaging of cellular metabolism and collagen second-harmonic generation for assessing cell-based therapies. Additionally, we discuss the potential of label-free imaging for quality control of cell-based therapies, as well as the current limitations and potential future directions of label-free imaging technologies.

Whole Blood Resuscitation is Safe in Pediatric Trauma Patients: A Multicenter Study

INTRODUCTION

Whole blood (WB) resuscitation has been associated with a mortality benefit in trauma patients. Several small series report the safe use of WB in the pediatric trauma population. We performed a subgroup analysis of the pediatric patients from a large prospective multicenter trial comparing patients receiving WB or blood component therapy (BCT) during trauma resuscitation. We hypothesized that WB resuscitation would be safe compared to BCT resuscitation in pediatric trauma patients.

METHODS

This study included pediatric trauma patients (0-17 y), from ten level-I trauma centers, who received any blood transfusion during initial resuscitation. Patients were included in the WB group if they received at least one unit of WB during their resuscitation, and the BCT group was composed of patients receiving traditional blood product resuscitation. The primary outcome was in-hospital mortality with secondary outcomes being complications. Multivariate logistic regression was performed to assess for mortality and complications in those treated with WB vs BCT.

RESULTS

Ninety patients, with both penetrating and blunt mechanisms of injury (MOI), were enrolled in the study (WB: 62 (69%), BCT: 28 (21%)). Whole blood patients were more likely to be male. There were no differences in age, MOI, shock index, or injury severity score between groups. On logistic regression, there was no difference in complications. Mortality was not different between the groups (P = .983).

CONCLUSION

Our data suggest WB resuscitation is safe when compared to BCT resuscitation in the care of critically injured pediatric trauma patients.

Transcriptomic and proteomic retinal pigment epithelium signatures of age-related macular degeneration

There are currently no treatments for geographic atrophy, the advanced form of age-related macular degeneration. Hence, innovative studies are needed to model this condition and prevent or delay its progression. Induced pluripotent stem cells generated from patients with geographic atrophy and healthy individuals were differentiated to retinal pigment epithelium. Integrating transcriptional profiles of 127,659 retinal pigment epithelium cells generated from 43 individuals with geographic atrophy and 36 controls with genotype data, we identify 445 expression quantitative trait loci in cis that are asssociated with disease status and specific to retinal pigment epithelium subpopulations. Transcriptomics and proteomics approaches identify molecular pathways significantly upregulated in geographic atrophy, including in mitochondrial functions, metabolic pathways and extracellular cellular matrix reorganization. Five significant protein quantitative trait loci that regulate protein expression in the retinal pigment epithelium and in geographic atrophy are identified - two of which share variants with cis- expression quantitative trait loci, including proteins involved in mitochondrial biology and neurodegeneration. Investigation of mitochondrial metabolism confirms mitochondrial dysfunction as a core constitutive difference of the retinal pigment epithelium from patients with geographic atrophy. This study uncovers important differences in retinal pigment epithelium homeostasis associated with geographic atrophy.

Retinal ganglion cell-specific genetic regulation in primary open-angle glaucoma

To assess the transcriptomic profile of disease-specific cell populations, fibroblasts from patients with primary open-angle glaucoma (POAG) were reprogrammed into induced pluripotent stem cells (iPSCs) before being differentiated into retinal organoids and compared with those from healthy individuals. We performed single-cell RNA sequencing of a total of 247,520 cells and identified cluster-specific molecular signatures. Comparing the gene expression profile between cases and controls, we identified novel genetic associations for this blinding disease. Expression quantitative trait mapping identified a total of 4,443 significant loci across all cell types, 312 of which are specific to the retinal ganglion cell subpopulations, which ultimately degenerate in POAG. Transcriptome-wide association analysis identified genes at loci previously associated with POAG, and analysis, conditional on disease status, implicated 97 statistically significant retinal ganglion cell-specific expression quantitative trait loci. This work highlights the power of large-scale iPSC studies to uncover context-specific profiles for a genetically complex disease.

Autofluorescence Imaging to Evaluate Cellular Metabolism

Cellular metabolism is the process by which cells generate energy, and many diseases, including cancer, are characterized by abnormal metabolism. Reduced nicotinamide adenine (phosphate) dinucleotide (NAD(P)H) and oxidized flavin adenine dinucleotide (FAD) are coenzymes of metabolic reactions. NAD(P)H and FAD exhibit autofluorescence and can be spectrally isolated by excitation and emission wavelengths. Both coenzymes, NAD(P)H and FAD, can exist in either a free or protein-bound configuration, each of which has a distinct fluorescence lifetime-the time for which the fluorophore remains in the excited state. Fluorescence lifetime imaging (FLIM) allows quantification of the fluorescence intensity and lifetimes of NAD(P)H and FAD for label-free analysis of cellular metabolism. Fluorescence intensity and lifetime microscopes can be optimized for imaging NAD(P)H and FAD by selecting the appropriate excitation and emission wavelengths. Metabolic perturbations by cyanide verify autofluorescence imaging protocols to detect metabolic changes within cells. This article will demonstrate the technique of autofluorescence imaging of NAD(P)H and FAD for measuring cellular metabolism.

Association of COVID-19 With Achieving Time-to-Surgery Benchmarks in Patients With Musculoskeletal Trauma

Question

Were resource constraints due to the COVID-19 pandemic associated with a delay in urgent fracture surgery beyond national time-to-surgery benchmarks?

Findings

In this cohort pre-post study that included 3589 patients, there was no association between time to surgery and COVID-19 in either open fracture or closed femur/hip fracture cohorts.

Meaning

Despite concerns that the unprecedented challenges associated with the COVID-19 pandemic would delay acute management of urgent surgery, many hospital systems within the US were able to implement strategies in keeping with time-to-surgery standards for orthopedic trauma.

Importance

In response to the COVID-19 pandemic, many hospital systems were forced to reduce operating room capacity and reallocate resources. The outcomes of these policies on the care of injured patients and the maintenance of emergency services have not been adequately reported.

Objective

To evaluate whether the COVID-19 pandemic was associated with delays in urgent fracture surgery beyond national time-to-surgery benchmarks.

Design, Setting, and Participants

This retrospective cohort study used data collected in the Program of Randomized Trials to Evaluate Preoperative Antiseptic Skin Solutions in Orthopaedic Trauma among at 20 sites throughout the US and Canada and included patients who sustained open fractures or closed femur or hip fractures.

Exposure

COVID-19–era operating room restrictions were compared with pre–COVID-19 data.

Main Outcomes and Measures

Surgery within 24 hours after injury.

Results

A total of 3589 patients (mean [SD] age, 55 [25.4] years; 1913 [53.3%] male) were included in this study, 2175 pre–COVID-19 and 1414 during COVID-19. A total of 54 patients (3.1%) in the open fracture cohort and 407 patients (21.8%) in the closed hip/femur fracture cohort did not meet 24-hour time-to-surgery benchmarks. We were unable to detect any association between time to operating room and COVID-19 era in either open fracture (odds ratio [OR], 1.40; 95% CI, 0.77-2.55; P = .28) or closed femur/hip fracture (OR, 1.01; 95% CI, 0.74-1.37; P = .97) cohorts. In the closed femur/hip fracture cohort, there was no association between time to operating room and regional COVID-19 prevalence (OR, 1.07; 95% CI, 0.70-1.64; P = .76).

Conclusions and Relevance

In this cohort study, there was no association between meeting time-to-surgery benchmarks in either open fracture or closed femur/hip fracture during the COVID-19 pandemic compared with before the pandemic. This is counter to concerns that the unprecedented challenges associated with managing the COVID-19 pandemic would be associated with clinically significant delays in acute management of urgent surgical cases and suggests that many hospital systems within the US were able to effectively implement policies consistent with time-to-surgery standards for orthopedic trauma in the context of COVID-19–related resource constraints.

Electrocardiographic characteristics of patients with coronavirus disease 2019 (COVID-2019) related pneumonia at first presentation

Funding Acknowledgements

Type of funding sources: None.

Purpose

To evaluate electrocardiographic (ECG) characteristics at first presentation in patients with possible coronavirus disease (COVID-19) pneumonia.

Methods and results

356 patients presenting at the emergency room with possible COVID-19 pneumonia based on clinical presentation and computed tomography findings were included and subdivided into a COVID-19 positive group ([COVID-19-positive], n = 231, 65%) and a COVID-19 negative group ([COVID-19-negative], n = 125, 35%) based on polymerase chain reaction tests.

The study population was predominantly middle aged-elderly (67 ± 14 year; n = 235, 66% male). Mortality rate was 24% after 1-month follow-up. There were no significant (NS) differences in sex, age, and mortality between the COVID-19-positive and COVID-19-negative group. 

Atrial fibrillation (AF) was common (9%), though its prevalence was NS (regression analyses adjusted for age and sex) different in the COVID-19-positive vs. the COVID-19-negative group. ECG characteristics reflecting atrial enlargement and repolarization abnormalities were frequently present (<38% and 14% respectively). No significant differences were found between the COVID-19-positive vs. the COVID-19-negative group for the majority of morphological ECG characteristics (Figure 1 for more detailed data). 

Conclusion

AF and ECG characteristics reflecting atrial enlargement and repolarization abnormalities are commonly present in COVID-19 patients. The prevalence of these ECG characteristics however do NS differ from their COVID-19-negative counterparts.

Pragmatic randomized trial evaluating pre-operative aqueous antiseptic skin solution in open fractures (Aqueous-PREP): the feasibility of a cluster randomized crossover study

Background

Preoperative antiseptic skin solutions are used prior to most surgical procedures; however, there is no definitive research comparing infection-related outcomes following use of the various solutions available to orthopedic trauma surgeons. The objective of this pilot study was to test the feasibility of a cluster randomized crossover trial that assesses the comparative effectiveness of a 10% povidone-iodine solution versus a 4% chlorhexidine gluconate solution for the management of open fractures.

Methods

Two orthopedic trauma centers participated in this pilot study. Each of these clinical sites was randomized to a starting solution (povidone-iodine solution or chlorhexidine gluconate) then subsequently crossed over to the other treatment after 2 months. During the 4-month enrollment phase, we assessed compliance, enrollment rates, participant follow-up, and accurate documentation of the primary clinical outcome. Feasibility outcomes included (1) the implementation of the interventions during a run-in period; (2) enrollment of participants during two 2-month enrollment phases; (3) application of the trial interventions as per the cluster randomization crossover scheme; (4) participant follow-up; and (5) accurate documentation of the primary outcome (surgical site infection). Feasibility outcomes were summarized using descriptive statistics reported as means (standard deviation) or medians (first quartile, third quartile) for continuous variables depending on their distribution and counts (percentage) for categorical variables. Corresponding 95% confidence intervals (CIs) were also reported.

Results

All five of the criteria for feasibility were met. During the run-in phase, all 18 of the eligible patients identified at the two clinical sites received the correct cluster-assigned treatment. A total of 135 patients were enrolled across both sites during the 4-month recruitment phase, which equates to 92% (95% CI 85.9 to 96.4%) of eligible patients being enrolled. Compliance with the assigned treatment in the pilot study was 98% (95% CI 93.5 to 99.8%). Ninety-eight percent (95% CI 93.5 to 99.8%) of participants completed the 90-day post-surgery follow-up and the primary outcome (SSI) was accurately documented for 100% (95% CI 96.6 to 100.0%) of the participants.

Conclusions

These results confirm the feasibility of a definitive study comparing antiseptic solutions using a cluster randomized crossover trial design. Building upon the infrastructure established during the pilot phase, a definitive study has been successfully initiated.

Trial registration

ClincialTrials.gov, number NCT03385304. Registered December 28, 2017.

Managing work flow in high enrolling trials: The development and implementation of a sampling strategy in the PREPARE trial

Introduction

Pragmatic trials in comparative effectiveness research assess the effects of different treatment, therapeutic, or healthcare options in clinical practice. They are characterized by broad eligibility criteria and large sample sizes, which can lead to an unmanageable number of participants, increasing the risk of bias and affecting the integrity of the trial. We describe the development of a sampling strategy tool and its use in the PREPARE trial to circumvent the challenge of unmanageable work flow.

Methods

Given the broad eligibility criteria and high fracture volume at participating clinical sites in the PREPARE trial, a pragmatic sampling strategy was needed. Using data from PREPARE, descriptive statistics were used to describe the use of the sampling strategy across clinical sites. A Chi-square test was performed to explore whether use of the sampling strategy was associated with a reduction in the number of missed eligible patients.

Results

7 of 20 clinical sites (35%) elected to adopt a sampling strategy. There were 1539 patients excluded due to the use of the sampling strategy, which represents 30% of all excluded patients and 20% of all patients screened for participation. Use of the sampling strategy was associated with lower odds of missed eligible patients (297/4545 (6.5%) versus 341/3200 (10.7%) p < 0.001).

Conclusions

Implementing a sampling strategy in the PREPARE trial has helped to limit the number of missed eligible patients. This sampling strategy represents a simple, easy to use tool for managing work flow at clinical sites and maintaining the integrity of a large trial.

Exposure to bisphenol A differentially impacts neurodevelopment and behavior in Drosophila melanogaster from distinct genetic backgrounds

Bisphenol A (BPA) is a ubiquitous environmental chemical that has been linked to behavioral differences in children and shown to impact critical neurodevelopmental processes in animal models. Though data is emerging, we still have an incomplete picture of how BPA disrupts neurodevelopment; in particular, how its impacts may vary across different genetic backgrounds. Given the genetic tractability of Drosophila melanogaster, they present a valuable model to address this question. Fruit flies are increasingly being used for assessment of neurotoxicants because of their relatively simple brain structure and variety of measurable behaviors. Here we investigated the neurodevelopmental impacts of BPA across two genetic strains of Drosophila-w¹¹¹⁸ (control) and the Fragile X Syndrome (FXS) model-by examining both behavioral and neuronal phenotypes. We show that BPA induces hyperactivity in larvae, increases repetitive grooming behavior in adults, reduces courtship behavior, impairs axon guidance in the mushroom body, and disrupts neural stem cell development in the w¹¹¹⁸ genetic strain. Remarkably, for every behavioral and neuronal phenotype examined, the impact of BPA in FXS flies was either insignificant or contrasted with the phenotypes observed in the w¹¹¹⁸ strain. This data indicates that the neurodevelopmental impacts of BPA can vary widely depending on genetic background and suggests BPA may elicit a gene-environment interaction with Drosophila fragile X mental retardation 1 (dFmr1)-the ortholog of human FMR1, which causes Fragile X Syndrome and is associated with autism spectrum disorder.

A novel trigger-substrate mechanism based on clinically concealed repolarization abnormalities underlies idiopathic ventricular fibrillation

Background

Sudden cardiac arrest (SCA) is most often due to ventricular fibrillation (VF). When no cause is found during diagnostic follow-up, fibrillation is classified as idiopathic (iVF). We hypothesize that a critical functional substrate-trigger interaction underlies iVF.

Purpose

To study electrophysiological triggers and substrate for iVF in a clinical cohort; and seek mechanistic explanations in explanted pig hearts and computer models mimicking trigger-substrate interactions.

Methods

Repolarization time (RT) isochrones on the epicardium were studied with electrocardiographic imaging (ECGI) in patients with iVF, patients with frequent monomorphic premature ventricular complexes (fmPVC) but no structural disease or SCA, and controls without cardiovascular disease.

RT gradients were created in explanted, Langendorff-perfused pig hearts by local infusion of dofetilide (“dof”, 250 nM, delaying RT) and pinacidil (“pin”, 30 μM, shortening RT) in adjacent regions of the heart. Arrhythmia inducibility was tested by programmed stimulation (8 atrial stimuli [S1] followed by one ventricular stimulus [S2] paced at regions of early or late RT).

A computational ventricular monodomain model was used to study the location-dependency of trigger-substrate interaction; RT gradients were created by local changes in potassium channel conductance.

Results

Although QTc values were similar, iVF survivors (n=11) displayed significantly steeper RT gradients than controls (n=10) or fmPVC individuals (n=7): 269±111 vs 179±40 vs 171±76 ms/cm respectively (panel A). Unipolar electrograms (EGMs) at the gradients displayed a change in polarity of the local T wave (B). In iVF, PVCs originated more often from regions with early RT than in fmPVC individuals (yellow circles in A; 64% vs 14%).

In the explanted hearts (C), drug infusion resulted in similar RT gradients and polarity changes of EGM T waves (D-E). VF inducibility by pacing of the early RT region (D) increased significantly with steeper RT gradients (baseline: 3/6 hearts inducible, dof+pin: 3/3). Pacing of late RT regions (E) did not induce arrhythmias in baseline (0/6) nor with RT gradients (0/3). For similar pacing intervals at the early RT region, the 12-lead ECG R-on-T morphology was similar but VF only occurred in the presence of RT gradients (F).

In the computer model, the number of inducible pacing intervals critically depended on the stimulus location (G).

Conclusion

Combined, these results demonstrate that R-on-T superposition per se is insufficient to explain arrhythmogenesis. Rather, not only the temporal coupling interval but also the spatial origin of PVCs in relationship to the degree of local repolarization abnormalities are critical elements. In iVF, a substrate of RT gradients (panel H1) with triggers from early RT regions (H2) precipitate reentry (H3). Noninvasive ECGI can uncover these substrate and trigger characteristics in (at least a subset of) iVF survivors.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Netherlands Organization for Scientific Research Veni grant TTW 16772, French National Research Agency (ANR-10-IAHU04-LIRYC)

MTOR signaling orchestrates stress-induced mutagenesis, facilitating adaptive evolution in cancer

In microorganisms, evolutionarily conserved mechanisms facilitate adaptation to harsh conditions through stress-induced mutagenesis (SIM). Analogous processes may underpin progression and therapeutic failure in human cancer. We describe SIM in multiple in vitro and in vivo models of human cancers under nongenotoxic drug selection, paradoxically enhancing adaptation at a competing intrinsic fitness cost. A genome-wide approach identified the mechanistic target of rapamycin (MTOR) as a stress-sensing rheostat mediating SIM across multiple cancer types and conditions. These observations are consistent with a two-phase model for drug resistance, in which an initially rapid expansion of genetic diversity is counterbalanced by an intrinsic fitness penalty, subsequently normalizing to complete adaptation under the new conditions. This model suggests synthetic lethal strategies to minimize resistance to anticancer therapy.

Factors Impacting Efficacy of AAV-Mediated CRISPR-Based Genome Editing for Treatment of Choroidal Neovascularization

Frequent injections of anti-vascular endothelial growth factor (anti-VEGF) agents are a clinical burden for patients with neovascular age-related macular degeneration (AMD). Genomic disruption of VEGF-A using adeno-associated viral (AAV) delivery of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 has the potential to permanently suppress aberrant angiogenesis, but the factors that determine the optimal efficacy are unknown. Here, we investigate two widely used Cas9 endonucleases, SpCas9 and SaCas9, and evaluate the relative contribution of AAV-delivery efficiency and genome-editing rates in vivo to determine the mechanisms that drive successful CRISPR-based suppression of VEGF-A, using a mouse model of laser-induced choroidal neovascularization (CNV). We found that SpCas9 demonstrated higher genome-editing rates, greater VEGF reduction, and more effective CNV suppression than SaCas9, despite similar AAV transduction efficiency between a dual-vector approach for SpCas9 and single-vector system for SaCas9 to deliver the Cas9 orthologs and single guide RNAs (gRNAs). Our results suggest that successful VEGF knockdown using AAV-mediated CRISPR systems may be determined more by the efficiency of genome editing rather than viral transduction and that SpCas9 may be more effective than SaCas9 as a potential therapeutic strategy for CRISPR-based treatment of CNV in neovascular AMD.

Effectiveness of Iodophor vs Chlorhexidine Solutions for Surgical Site Infections and Unplanned Reoperations for Patients Who Underwent Fracture Repair: The PREP-IT Master Protocol

IMPORTANCE

The risk of developing a surgical site infection after extremity fracture repair is nearly 5 times greater than in most elective orthopedic surgical procedures. For all surgical procedures, it is standard practice to prepare the operative site with an antiseptic solution; however, there is limited evidence to guide the choice of solution used for orthopedic fracture repair.

OBJECTIVE

To compare the effectiveness of iodophor vs chlorhexidine solutions to reduce surgical site infections and unplanned fracture-related reoperations for patients who underwent fracture repair.

DESIGN, SETTING, AND PARTICIPANTS

The PREP-IT (Program of Randomized Trials to Evaluate Pre-operative Antiseptic Skin Solutions in Orthopaedic Trauma) master protocol will be followed to conduct 2 multicenter pragmatic cluster randomized crossover trials, Aqueous-PREP (Pragmatic Randomized Trial Evaluating Pre-Operative Aqueous Antiseptic Skin Solution in Open Fractures) and PREPARE (Pragmatic Randomized Trial Evaluating Pre-Operative Alcohol Skin Solutions in Fractured Extremities). The Aqueous-PREP trial will compare 4% aqueous chlorhexidine vs 10% povidone-iodine for patients with open extremity fractures. The PREPARE trial will compare 2% chlorhexidine in 70% isopropyl alcohol vs 0.7% iodine povacrylex in 74% isopropyl alcohol for patients with open extremity fractures and patients with closed lower extremity or pelvic fractures. Both trials will share key aspects of study design and trial infrastructure. The studies will follow a pragmatic cluster randomized crossover design with alternating treatment periods of approximately 2 months. The primary outcome will be surgical site infection and the secondary outcome will be unplanned fracture-related reoperations within 12 months. The Aqueous-PREP trial will enroll a minimum of 1540 patients with open extremity fractures from at least 12 hospitals; PREPARE will enroll a minimum of 1540 patients with open extremity fractures and 6280 patients with closed lower extremity and pelvic fractures from at least 18 hospitals. The primary analyses will adhere to the intention-to-treat principle and account for potential between-cluster and between-period variability. The patient-centered design, implementation, and dissemination of results are guided by a multidisciplinary team that includes 3 patients and other relevant stakeholders.

DISCUSSION

The PREP-IT master protocol increases efficiency through shared trial infrastructure and study design components. Because prophylactic skin antisepsis is used prior to all surgical procedures and the application, cost, and availability of all study solutions are similar, the results of the PREP-IT trials are poised to inform clinical guidelines and bring about an immediate change in clinical practice.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT03385304 and NCT03523962.

A Surveillance System for the Maternal and Child Health (MCH) Population During the COVID-19 Pandemic

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent for coronavirus disease 2019 (COVID-19), and its ensuing mitigation measures have negatively affected the Maternal and Child Health (MCH) population. There is currently no surveillance system established to enhance our understanding of SARS-CoV-2 transmission to guide policy decision making to protect the MCH population in this pandemic. Based on reports of community and household spread of this novel infection, we present an approach to a robust family-centered surveillance system for the MCH population. The surveillance system encapsulates data at the individual and community levels to inform stakeholders, policy makers, health officials and the general public about SARS-CoV-2 transmission dynamics within the MCH population.

Primary Lung Signet Ring Cell Carcinoma Presenting as a Cavitary Pancoast Tumor in a 32-Year-Old Man

Signet ring cell carcinoma, a subtype of adenocarcinoma, is a rare cause of primary lung cancer. The authors report a case of primary lung signet ring cell carcinoma presenting as a cavitary Pancoast tumor in a 32-year-old male smoker. Beyond the rarity of primary lung signet ring cell carcinoma itself, the youth of the patient, his smoking status, the presence of cavitation, and the location of the tumor in the superior sulcus make it especially atypical.

Inhibition of RhoA reduces propofol-mediated growth cone collapse, axonal transport impairment, loss of synaptic connectivity, and behavioural deficits

BACKGROUND

Exposure of the developing brain to propofol results in cognitive deficits. Recent data suggest that inhibition of neuronal apoptosis does not prevent cognitive defects, suggesting mechanisms other than neuronal apoptosis play a role in anaesthetic neurotoxicity. Proper neuronal growth during development is dependent upon growth cone morphology and axonal transport. Propofol modulates actin dynamics in developing neurones, causes RhoA-dependent depolymerisation of actin, and reduces dendritic spines and synapses. We hypothesised that RhoA inhibition prevents synaptic loss and subsequent cognitive deficits. The present study tested whether RhoA inhibition with the botulinum toxin C3 (TAT-C3) prevents propofol-induced synapse and neurite loss, and preserves cognitive function.

METHODS

RhoA activation, growth cone morphology, and axonal transport were measured in neonatal rat neurones (5-7 days in vitro) exposed to propofol. Synapse counts (electron microscopy), dendritic arborisation (Golgi-Cox), and network connectivity were measured in mice (age 28 days) previously exposed to propofol at postnatal day 5-7. Memory was assessed in adult mice (age 3 months) previously exposed to propofol at postnatal day 5-7.

RESULTS

Propofol increased RhoA activation, collapsed growth cones, and impaired retrograde axonal transport of quantum dot-labelled brain-derived neurotrophic factor, all of which were prevented with TAT-C3. Adult mice previously treated with propofol had decreased numbers of total hippocampal synapses and presynaptic vesicles, reduced hippocampal dendritic arborisation, and infrapyramidal mossy fibres. These mice also exhibited decreased hippocampal-dependent contextual fear memory recall. All anatomical and behavioural changes were prevented with TAT-C3 pre-treatment.

CONCLUSION

Inhibition of RhoA prevents propofol-mediated hippocampal neurotoxicity and associated cognitive deficits.

Effect of Dextromethorphan-Quinidine on Agitation in Patients With Alzheimer Disease Dementia: A Randomized Clinical Trial

IMPORTANCE

Agitation is common among patients with Alzheimer disease; safe, effective treatments are lacking.

OBJECTIVE

To assess the efficacy, safety, and tolerability of dextromethorphan hydrobromide-quinidine sulfate for Alzheimer disease-related agitation.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2 randomized, multicenter, double-blind, placebo-controlled trial using a sequential parallel comparison design with 2 consecutive 5-week treatment stages conducted August 2012-August 2014. Patients with probable Alzheimer disease, clinically significant agitation (Clinical Global Impressions-Severity agitation score ≥4), and a Mini-Mental State Examination score of 8 to 28 participated at 42 US study sites. Stable dosages of antidepressants, antipsychotics, hypnotics, and antidementia medications were allowed.

INTERVENTIONS

In stage 1, 220 patients were randomized in a 3:4 ratio to receive dextromethorphan-quinidine (n = 93) or placebo (n = 127). In stage 2, patients receiving dextromethorphan-quinidine continued; those receiving placebo were stratified by response and rerandomized in a 1:1 ratio to dextromethorphan-quinidine (n = 59) or placebo (n = 60).

MAIN OUTCOMES AND MEASURES

The primary end point was change from baseline on the Neuropsychiatric Inventory (NPI) Agitation/Aggression domain (scale range, 0 [absence of symptoms] to 12 [symptoms occur daily and with marked severity]).

RESULTS

A total of 194 patients (88.2%) completed the study. With the sequential parallel comparison design, 152 patients received dextromethorphan-quinidine and 127 received placebo during the study. Analysis combining stages 1 (all patients) and 2 (rerandomized placebo nonresponders) showed significantly reduced NPI Agitation/Aggression scores for dextromethorphan-quinidine vs placebo (ordinary least squares z statistic, -3.95; P < .001). In stage 1, mean NPI Agitation/Aggression scores were reduced from 7.1 to 3.8 with dextromethorphan-quinidine and from 7.0 to 5.3 with placebo. Between-group treatment differences were significant in stage 1 (least squares mean, -1.5; 95% CI, -2.3 to -0.7; P<.001). In stage 2, NPI Agitation/Aggression scores were reduced from 5.8 to 3.8 with dextromethorphan-quinidine and from 6.7 to 5.8 with placebo. Between-group treatment differences were also significant in stage 2 (least squares mean, -1.6; 95% CI, -2.9 to -0.3; P=.02). Adverse events included falls (8.6% for dextromethorphan-quinidine vs 3.9% for placebo), diarrhea (5.9% vs 3.1% respectively), and urinary tract infection (5.3% vs 3.9% respectively). Serious adverse events occurred in 7.9% with dextromethorphan-quinidine vs 4.7% with placebo. Dextromethorphan-quinidine was not associated with cognitive impairment, sedation, or clinically significant QTc prolongation.

CONCLUSIONS AND RELEVANCE

In this preliminary 10-week phase 2 randomized clinical trial of patients with probable Alzheimer disease, combination dextromethorphan-quinidine demonstrated clinically relevant efficacy for agitation and was generally well tolerated.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01584440.

Workplace health and safety issues among community nurses: a study regarding the impact on providing care to rural consumers

OBJECTIVES

The objective of the study was to investigate the types of workplace health and safety issues rural community nurses encounter and the impact these issues have on providing care to rural consumers.

METHODS

The study undertook a narrative inquiry underpinned by a phenomenological approach. Community nursing staff who worked exclusively in rural areas and employed in a permanent capacity were contacted among 13 of the 16 consenting healthcare services. All community nurses who expressed a desire to participate were interviewed. Data were collected using semistructured interviews with 15 community nurses in rural and remote communities. Thematic analysis was used to analyse interview data.

RESULTS

The role, function and structures of community nursing services varied greatly from site to site and were developed and centred on meeting the needs of individual communities. In addition, a number of workplace health and safety challenges were identified and were centred on the geographical, physical and organisational environment that community nurses work across. The workplace health and safety challenges within these environments included driving large distances between client's homes and their office which lead to working in isolation for long periods and without adequate communication. In addition, other issues included encountering, managing and developing strategies to deal with poor client and carer behaviour; working within and negotiating working environments such as the poor condition of patient homes and clients smoking; navigating animals in the workplace; vertical and horizontal violence; and issues around workload, burnout and work-related stress.

CONCLUSIONS

Many nurses achieved good outcomes to meet the needs of rural community health consumers. Managers were vital to ensure that service objectives were met. Despite the positive outcomes, many processes were considered unsafe by community nurses. It was identified that greater training and capacity building are required to meet the needs among all staff.

Children with severe early childhood caries: streptococci genetic strains within carious and white spot lesions

Background and objectives

Mutans streptococci (MS) are one of the major microbiological determinants of dental caries. The objectives of this study are to identify distinct MS and non-MS streptococci strains that are located at carious sites and non-carious enamel surfaces in children with severe early childhood caries (S-ECC), and assess if cariogenic MS and non-cariogenic streptococci might independently exist as primary bacterial strains on distinct sites within the dentition of individual children.

Design

Dental plaque from children (N=20; aged 3–6) with S-ECC was collected from carious lesions (CLs), white spot lesions (WSLs) and non-carious enamel surfaces. Streptococcal isolates (N=10–20) from each site were subjected to polymerase chain reaction (PCR) to identify MS, and arbitrarily primed-PCR for assignment of genetic strains. Primary strains were identified as ≥50% of the total isolates surveyed at any site. In several cases, strains were characterized for acidurity using ATP-driven bioluminescence and subjected to PCR-determination of potential MS virulence products. Identification of non-MS was determined by 16S rRNA gene sequencing.

Results

Sixty-four independent MS or non-MS streptococcal strains were identified. All children contained 1–6 strains. In many patients (N=11), single primary MS strains were identified throughout the dentition. In other patients (N=4), primary MS strains were identified within CLs that were distinct from primary strains found on enamel. Streptococcus gordonii strains were identified as primary strains on enamel or WSLs in four children, and in general were less aciduric than MS strains.

Conclusions

Many children with S-ECC contained only a single primary MS strain that was present in both carious and non-carious sites. In some cases, MS and non-cariogenic S. gordonii strains were found to independently exist as dominant strains at different locations within the dentition of individual children, and the aciduric potential of these strains may influence susceptibility in the development of CLs.

Accurate quantitation of proteins involved in autoimmune disease using simple western (TECH2P.872)

Why do researchers use Western blots? Since the technique was developed thirty years ago it’s become a trusted method for confirming the presence or absence of a protein but lacks the quantitative rigor for accurate measurement of the amount of protein present. The process requires many steps which introduces multiple variables. While portions of the technique have been automated to improve consistency, until now there has been no major leap in the technology that propels this method of protein analysis from qualitative to quantitative. Simple Western is the modern evolution of traditional immunoassay techniques. Wes, the latest addition to the Simple Western platform, is an easy to use, fully automated system that removes the variability seen with traditional Westerns for more reproducible results run to run and between users. Researchers can now identify their protein and achieve reliable quantitation of their target proteins. To demonstrate the precision and data reliability of Wes we look at proteins indicative of autoimmune disease in human samples from either normal individuals or individuals suffering from the disease. Wes not only reduces the hands on time and the time to results, but generates highly reproducible data that gives researchers a high degree of confidence in the differences detected between the two disease states. Accurate quantitation of these proteins can lead to the identification of predictive biomarkers for either diagnosis or response to treatment.

Abstract 3212: Capillary electrophoresis for upstream and downstream biopharmaceutical development

In order to bring an antibody or other biologic drug to market, each step of the process needs to be carefully monitored. Charge heterogeneity and apparent MW via SDS-PAGE are two of the most commonly assessed parameters. Ideally, similar methods should be used from the beginning of development (low expression, complex matrix) to late in production and QC (high concentration, pure material).Capillary techniques such as iCE and CE-SDS are currently heavily used in downstream product development but pose challenges for small scale screening and characterization during cell culture and formulation development. Here we present the Simple Western that combines in one novel instrument, Peggy, capillary electrophoresis with an immunoassay to provide highly reproducible and fully automated analysis of monoclonal antibodies. This sensitive technology measures either size or charge in complex samples and provides critical charge heterogeneity, size, and product titer information without the need for sample purification. Data will be presented demonstrating the application of the Simple Western technique and the iCE technology for the analysis of monoclonal antibodies against VEGF and the ability of the two techniques to provide consistency of data across the whole range of product development. In addition we show examples for the unique capability of this technology to assess affinity information for these anti VEGF antibodies to different charge isoforms of VEGF.

Citation Format: Uyen Nguyen, Francisco Ramirez, Scott Mack, Susan Darling, John Proctor, Annegret Boge. Capillary electrophoresis for upstream and downstream biopharmaceutical development. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3212. doi:10.1158/1538-7445.AM2013-3212

Effects of grazing on leaf area index, fractional cover and evapotranspiration by a desert phreatophyte community at a former uranium mill site on the Colorado Plateau

This study employed ground and remote sensing methods to monitor the effects of grazing on leaf area index (LAI), fractional cover (f(c)) and evapotranspiration (ET) of a desert phreatophyte community over an 11 year period at a former uranium mill site on the Colorado Plateau, U.S. Nitrate, ammonium and sulfate are migrating away from the mill site in a shallow alluvial aquifer. The phreatophyte community, consisting of Atriplex canescens (ATCA) and Sarcobatus vermiculatus (SAVE) shrubs, intercepts groundwater and could potentially slow the movement of the contaminant plume through evapotranspiration (ET). However, the site has been heavily grazed by livestock, reducing plant cover and LAI. We used livestock exclosures and revegetation plots to determine the effects of grazing on LAI, f(c) and ET, then projected the findings over the whole site using multi-platform remote sensing methods. We show that ET is approximately equal to annual precipitation at the site, but when ATCA and SAVE are protected from grazing they can develop high f(c) and LAI values, and ET can exceed annual precipitation, with the excess coming from groundwater discharge. Therefore, control of grazing could be an effective method to slow migration of contaminants at this and similar sites in the western U.S.

Abstract 1262: Simple western and NanoPro analysis of key EGF signaling cascade proteins

Aberrant expression and signaling in the EGF signaling pathway is a common occurrence in a variety of cancers including breast cancer. Understanding how EGF signaling impacts disease progression is key to the development of novel therapeutics. Detection of important protein targets in cancer samples frequently employs Western blot analysis. In-depth phosphorylation analysis often requires 2D gels which are extremely variable and labor intensive, followed by MS analysis. Each of these methods have their advantages and challenges. This study employs the use of two novel nano-scale capillary-based electrophoresis and immunodetection technologies to characterize and validate subtle changes in key protein targets involved in the regulation of disease progression. The Simon system performs size-based separation of proteins, known as Simple Western assays. Alternatively, NanoPro systems utilize charge-based separation via isoelectric focusing (IEF). Both methods utilize capillary electrophoresis (CE) to perform the separation events. Both Simon and NanoPro instruments provide automated workflow eliminating the need for manual processing of multiple steps traditionally needed to carry out either of these separation and detection processes. Proteins from a single sample preparation were analyzed on two platforms: either in a native conformation using charge-based separation (NanoPro assays) or in a denatured state followed by size-based separation (Simple Western assays). Both methods incorporate immunodetection to monitor both subtle and specific changes to key signaling protein targets. Utilizing both platforms allowed for detailed analysis of post-translational modifications (charge-based) and protein abundance (size-based) within a prepared sample. As a validation of synergy between the platforms, we investigated key members of the EGF signaling cascade in different phosphorylation states. We showed that the same cellular lysate preparation can be used for charge- or size-based separation. Advantages of Simple Western and NanoPro assays over gels (1D and 2D) and traditional Westerns include ease of use, minimal user intervention, automatic analysis and excellent reproducibility which ultimate results in better data quality to characterize key regulatory events involved with cancer progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1262. doi:1538-7445.AM2012-1262

Variation and expression of dihydrofolate reductase (DHFR) in relation to spina bifida

The dihydrofolate reductase (DHFR) enzyme is important for folate availability, folate turnover and DNA synthesis. The 19-bp deletion in intron-1 of DHFR has been associated with the risk of having spina bifida affected offspring, supposedly by changing DHFR gene expression. A 9-bp repeat in exon 1 of the mutS homolog 3 (MSH3) gene was recently demonstrated to be also located in the 5'UTR of DHFR and may possibly affect DHFR gene expression as well. We examined the association between these DHFR variants and spina bifida risk and investigated their effect on DHFR expression. Our study population, consisting of 121 mothers of a spina bifida affected child, 109 spina bifida patients, 292 control women and 234 pediatric controls was screened for the DHFR 19-bp deletion and the DHFR 9-bp repeat. DHFR gene expression was measured in 66 spina bifida patients, using real-time PCR analysis. In this study population, the DHFR 19-bp del/del genotype was not associated with spina bifida risk in mothers and children (OR: 0.8; 95%CI: 0.4-1.5 and OR: 1.2; 95%CI: 0.6-2.2, respectively) and both the WT/del and the del/del genotype did not affect DHFR expression relative to the WT/WT genotype (relative expression=0.89, p=0.46 and relative expression=1.26, p=0.24, respectively). The DHFR 9-bp repeat was not associated with spina bifida risk in mothers and children. DHFR expression of the 6/6 allele was 73% increased compared to the 3/3 allele, although not significantly (relative expression=1.73, p=0.09). We did not find evidence for an effect of the DHFR 19-bp deletion or 9-bp repeat on spina bifida risk in mothers and children. An effect of the 6/6 repeat genotype on DHFR expression cannot be ruled out.

Isoelectric focusing technology quantifies protein signaling in 25 cells

A previously undescribed isoelectric focusing technology allows cell signaling to be quantitatively assessed in <25 cells. High-resolution capillary isoelectric focusing allows isoforms and individual phosphorylation forms to be resolved, often to baseline, in a 400-nl capillary. Key to the method is photochemical capture of the resolved protein forms. Once immobilized, the proteins can be probed with specific antibodies flowed through the capillary. Antibodies bound to their targets are detected by chemiluminescence. Because chemiluminescent substrates are flowed through the capillary during detection, localized substrate depletion is overcome, giving excellent linearity of response across several orders of magnitude. By analyzing pan-specific antibody signals from individual resolved forms of a protein, each of these can be quantified, without the problems associated with using multiple antibodies with different binding avidities to detect individual protein forms.

ORFDB: an information resource linking scientific content to a high-quality Open Reading Frame (ORF) collection

The ORFDB (http://orf.invitrogen.com/) represents an ongoing effort at Invitrogen Corporation to integrate relevant scientific data with an evolving collection of human and mouse Open Reading Frame (ORF) clones (Ultimate ORF Clones). The ORFDB serves as a central data warehouse enabling researchers to search the ORF collection through its web portal ORFBrowser, allowing researchers to find the Ultimate ORF clones by blast, keyword, GenBank accession, gene symbol, clone ID, Unigene ID, LocusLink ID or through functional relationships by browsing the collection via the Gene Ontology (GO) Browser. As of October 2003, the ORFDB contains 6200 human and 2870 mouse Ultimate ORF clones. All Ultimate ORF clones have been fully sequenced with high quality, and are matched to public reference protein sequences. In addition, the cloned ORFs have been extensively annotated across six categories: Gene, ORF, Clone Format, Protein, SNP and Genomic links, with the information assembled in a format termed the ORFCard. The ORFCard represents an information repository that documents the sequence quality, alignment with respect to public protein sequences, and the latest publicly available information associated with each human and mouse gene represented in the collection.

Use of floating electrodes in transient isotachophoresis to increase the sensitivity of detection

We report a protocol for on-chip electrophoretic sample loading and sample component separation in which each operation requires simultaneous control of the potential of only two electrodes: during the sample-loading phase, the potentials at the ends of the separation channel are electrically floating; during electrophoresis of the sample mixture down the separation channel, the potentials at the ends of the sample-introduction channel are floating. This method, which we call "floating-stacking," avoids the dispersion/distortion of the sample plug that is commonly associated with simultaneous electrical control of only two electrodes in a crossed-channel or offset-double-tee injection system. Further, when this floating loading/separation is done in the presence of back-transient-isotachophoresis, sample loss from the plug of material being injected is minimal and a significant concentration increase--up to 13x--of the sample components in the separated bands occurs relative to the commonly used "pinch-and-pull-back" technique (which requires simultaneous electrical control of four electrodes).

The BirthPlace collaborative practice model: results from the San Diego Birth Center Study

Objective: The search for quality, cost-effective health care programs in the United States is now a major focus in the era of health care reform. New programs need to be evaluated as alternatives are developed in the health care system. The BirthPlace program provides comprehensive perinatal services with certified nurse-midwives and obstetricians working together in an integrated collaborative practice serving a primarily low-income population. Low-risk women are delivered by nurse-midwives in a freestanding birth center (The BirthPlace), which is one component of a larger integrated health network. All others are delivered by team obstetricians at the affiliated tertiary hospital. Wellness, preventive measures, early intervention, and family involvement are emphasized. The San Diego Birth Center Study is a 4-year research project funded by the U.S. Federal Agency for Health Care Policy and Research (#R01-HS07161) to evaluate this program. The National Birth Center Study (NEJM, 1989; 321(26): 1801-11) described the advantages and safety of freestanding birth centers. However, a prospective cohort study with a concurrent comparison group of comparable risk had not been conducted on a collaborative practice-freestanding birth center model to address questions of safety, cost, and patient satisfaction.Methods: The specific aims of this study are to compare this collaborative practice model to the traditional model of perinatal health care (physician providers and hospital delivery). A prospective cohort study comparing these two health care models was conducted with a final expected sample size of approximately 2,000 birth center and 1,350 traditional care subjects. Women were recruited from both the birth center and traditional care programs (private physicians offices and hospital based clinics) at the beginning of prenatal care and followed through the end of the perinatal period. Prenatal, intrapartum, postpartum and infant morbidity and mortality are being compared along with cost-effectiveness and acceptance of the model by patients. Data collection occurred primarily through medical record abstraction with the addition of two patient questionnaires. Comparability of the cohorts was established by using a validated methodology to determine medical/perinatal risk and birth center eligibility, which included assessment by two CNMs and an independent blind review by a perinatologist. The cost analysis uses a resource-utilization approach and new methodologies such as activity-based-costing to compare costs from both the perspective of the payor and the health care provider. Patient satisfaction was measured using a self-administered patient questionnaire.Results: Current preliminary results from approximately 38% of the final expected study sample are available. Crude and adjusted analysis have been conducted. Overall, the preliminary results suggest similar morbidity and mortality in the two groups. Fetal deaths are 0.75% in the index and 0.64% in the comparison group, with early neonatal deaths at 0.26% and 0.23%, respectively. The traditional care group showed adjusted rate differences of 5.83% more major maternal intrapartum complications and 9% more NICU admissions. While the birth center group showed adjusted rate differences of 5.5% more low birth weight and 0.95% more preterm birth. For other outcomes, the birth center group showed an adjusted rate difference of 22.34% more exclusive breastfeeding at discharge. Also, there was less utilization of cesarean section and assisted delivery in the birth center group as compared to the traditional care group. The adjusted rate difference for normal spontaneous vaginal deliveries in nulliparas was 10.23% more in the birth center group, with similar results in multiparas with and without history of cesarean (28.88% and 7.84%, respectively). Preliminary results also show that the average total cost for pregnancy-related services paid by California Medicaid was $4,550 for the birth center and $5,535 for the traditional care group. Final results based on the full study sample (full data available February 1998) details of payor costs such as provider, facility, NICU, and ancillary along with costs from the health care system perspective and patient satisfaction results will be presented.Conclusion: Current results suggest similar morbidity and mortality between the birth center program and traditional care groups, with less resource utilization translating to lower costs in the collaborative practice model. Results suggest that collaborative practice using a freestanding birth center as an adjunct to an integrated perinatal health care system may provide a quality, lower-cost alternative for the provision of perinatal services.

An immunofluorescence study of the effects of ultraviolet radiation on the organization of microfilaments, keratin intermediate filaments, and microtubules in human keratinocytes

Indirect immunofluorescence microscopy has been used to investigate the ultraviolet (UV) radiation induced disruption of the organization of microfilaments, keratin intermediate filaments, and microtubules in cultured human epidermal keratinocytes. Following irradiation, concurrent changes in the organization of the three major cytoskeletal components were observed in cells incubated under low Ca2+ (0.15 mM) conditions. UV irradiation induced a dose-dependent condensation of keratin filaments into the perinuclear region. This collapse of the keratin network was accompanied by the reorganization of microfilaments into rings and a restricted distribution of microtubules, responses normally elicited by exposure to high Ca2+ (1.05 mM) medium. The UV induced alteration of the keratin network appears to disrupt the interactions between keratin and actin, permitting the reorganization of actin filaments in the absence of Ca2+ stimulation. In addition to the perinuclear condensation of keratin filaments, UV irradiation inhibits the Ca2+ induced formation of keratin alignments at the membrane of apposed cells if UV treatment precedes exposure to high Ca2+ medium. Incubation of keratinocytes in high Ca2+ medium for 24 hours prior to irradiation results in the stabilization of membrane associated keratin alignments and a reduced susceptibility of cytoplasmic keratin filaments to UV induced disruption. Unlike results from investigations with isogenic skin fibroblasts, no UV induced disassembly of microtubules was discernible in irradiated human keratinocytes.

An immunofluorescence study of the calcium-induced coordinated reorganization of microfilaments, keratin intermediate filaments, and microtubules in cultured human epidermal keratinocytes

Indirect immunofluorescence microscopy has been used to investigate the coordinated reorganization of microtubules, microfilaments, and keratin intermediate filaments in cultured human epidermal keratinocytes following a switch from low-Ca++ (0.15 mM) medium to high-Ca++ (1.05 mM) medium. A dramatic reorganization occurs concurrently in the three major cytoskeletal components shortly after the calcium switch. The most prominent features are the alignment of keratin filaments at the plasma membranes of apposed cells, the induction of microfilament rings, the restriction of microtubules to the area within the boundaries of the microfilament rings, and the alignment of actin bundles at cell borders. Additional changes are observed in terminally differentiated cells. This is the first report that describes simultaneous changes in the organization of the three major cytoskeletal components of epidermal keratinocytes. Cytochalasin D and demecolcine (colcemid) studies were performed to determine whether the organization of microtubules, microfilaments, and keratin filaments, as well as the calcium-induced reorganization of these cytoskeletal elements, may be dependent on the existence of structural relationships between them. These studies demonstrate that the disruption of microfilaments results in the formation of a latticelike keratin network, with a close association of actin and keratin being maintained. The formation of keratin filament alignments occurs even in the absence of intact microfilaments. In addition, it was found that the Ca(++)-induced reorganization of microfilaments and keratin filaments is not dependent on an intact microtubule network. Furthermore, the reorganization of actin into concentric rings can be dissociated from changes in the organization of keratin filaments.