Feasibility and Acceptability of Mobile Phone-Based Surveys to Identify Mental Health Symptoms in Parents/Guardians of PICU Patients.

OBJECTIVE: Parents experience psychologic distress during their child's admission to a PICU, but effective screening for parental mental health symptoms is not the standard of care. We aimed to test the feasibility and acceptability of a mobile phone-based mental health survey for parents/guardians of PICU patients to facilitate their support by the PICU team. DESIGN: Post hoc analysis of a single-institution pilot study conducted in 2022. Mental health surveys were delivered by text message to parents/guardians of PICU patients over 1 month, beginning 3 days after their child's PICU admission. In-person interviews 1 month after hospital discharge were used to solicit participants' opinions on the survey platform and content. SETTING: A quaternary U.S. academic medical center. PARTICIPANTS: Parents/guardians of PICU patients. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Of the 53 participants who consented, 31 (58%) completed the study. Symptoms of acute stress (ASS) were the most common and most severe: 21 participants screened positive for ASS, and 20 of those that screened positive had "moderate" or "severe" symptoms. Among the 23 participants who screened positive for one mental health condition, 10 met the thresholds for all three. Scoring of the protocol's usability, acceptability, and feasibility showed a System Usability Scale equal to 82 of 100, an Acceptability of Intervention Measure score equal to 4.2 of 5, an Intervention Appropriateness Measure score equal to 4.5 of 5, and Feasibility of Intervention Measure score equal to 4.5 of 5. CONCLUSIONS AND RELEVANCE: Mobile phone-based screening for parental mental health symptoms is acceptable and may offer the advantage of privacy and flexibility.

Pediatric Acute Respiratory Distress Syndrome Severity and Health-Related Quality of Life Outcomes: Single-Center Retrospective Cohort, 2011-2017.

OBJECTIVES: To determine factors associated with health-related quality of life (HRQL) decline among pediatric acute respiratory distress syndrome (PARDS) survivors. DESIGN: Retrospective cohort study. SETTING: Academic children's hospital. PATIENTS: Three hundred fifteen children 1 month to 18 years old with an unplanned PICU admission from December 2011 to February 2017 enrolled in the hospital's Outcomes Assessment Program. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pre-admission baseline and median 6-week post-discharge HRQL were assessed using the Pediatric Quality of Life Inventory or the Functional Status II-R. Patients meeting retrospectively applied Second Pediatric Acute Lung Injury Consensus Conference criteria for PARDS were identified, and PARDS severity was classified using binary (mild/moderate, severe) and trichotomous (mild, moderate, severe) categorization for noninvasive ventilation and invasive mechanical ventilation (IMV). PARDS occurred in 41 of 315 children (13.0%). Clinically important HRQL decline (≥ 4.5 points) occurred in 17 of 41 patients (41.5%) with PARDS and 64 of 274 without PARDS (23.4%). On multivariable generalized linear regression adjusted for age, baseline Pediatric Overall Performance Category, maximum nonrespiratory Pediatric Logistic Organ Dysfunction score, diagnosis, length of stay, and time to follow-up, PARDS was associated with HRQL decline (adjusted relative risk [aRR], 1.70; 95% CI, 1.03-2.77). Four-hour and maximum PARDS severity were the only factors associated with HRQL decline. HRQL decline occurred in five of 18 patients with mild PARDS at 4 hours, five of 13 with moderate PARDS (aRR 2.35 vs. no PARDS [95% CI, 1.01-5.50]), and seven of ten with severe PARDS (aRR 2.56 vs. no PARDS [95% CI, 1.45-4.53]). The area under the receiver operating characteristic curve for discrimination of HRQL decline for IMV patients was 0.79 (95% CI, 0.66-0.91) for binary and 0.80 (95% CI, 0.69-0.93) for trichotomous severity categorization. CONCLUSIONS: HRQL decline is common among children surviving PARDS, and risk of decline is associated with PARDS severity. HRQL decline from baseline may be an efficient and clinically meaningful endpoint to incorporate into PARDS clinical trials.

Risk Factors for Positive Post-Traumatic Stress Disorder Screening and Associated Outcomes in Children Surviving Acute Respiratory Failure: A Secondary Analysis of the Randomized Evaluation of Sedation Titration for Respiratory Failure Clinical Trial.

OBJECTIVES: To identify risk factors and outcomes associated with a positive post-traumatic stress disorder (PTSD) screen following pediatric acute respiratory failure treated with invasive mechanical ventilation. DESIGN: Nonprespecified secondary analysis of a randomized clinical trial. SETTING: Thirty-one U.S. PICUs. PATIENTS: Children in the Randomized Evaluation of Sedation Titration for Respiratory Failure (RESTORE) trial (NCT00814099, ClinicalTrials.gov ) over 8 years old who completed PTSD screening 6 months after discharge. INTERVENTIONS: RESTORE sites were randomized to a targeted, nurse-directed sedation strategy versus usual care. MEASUREMENTS AND MAIN RESULTS: PTSD screening was completed by 102 subjects using the Child Post-Traumatic Stress Disorder Symptom Scale; a score of greater than or equal to 11 was considered screening positive for PTSD. Cognitive status was categorized using Pediatric Cerebral Performance Category; health-related quality of life (HRQL) was evaluated using child-reported Pediatric Quality of Life Inventory, Version 4.0. Thirty-one children (30%) screened positive for PTSD. Children with a positive screen endorsed symptoms in all categories: reexperiencing, avoidance, and hyperarousal. Most endorsed that symptoms interfered with schoolwork ( n = 18, 58%) and happiness ( n = 17, 55%). Screening positive was not associated with RESTORE treatment group. In a multivariable logistic model adjusting for age, sex, and treatment group, screening positive was independently associated with lower median income in the family's residential zip code (compared with income ≥ $80,000; income < $40,000 odds ratio [OR], 32.8; 95% CI, 2.3-458.1 and $40,000-$79,999 OR, 15.6; 95% CI, 1.3-182.8), renal dysfunction (OR 5.3, 95% CI 1.7-16.7), and clinically significant pain in the PICU (OR, 8.3; 95% CI, 1.9-35.7). Children with a positive screen experienced decline in cognitive function and impaired HRQL more frequently than children with a negative screen. CONCLUSIONS: Screening positive for PTSD is common among children following acute respiratory failure and is associated with lower HRQL and decline in cognitive function. Routine PTSD screening may be warranted to optimize recovery.

Family Presence at the PICU Bedside: A Single-Center Retrospective Cohort Study.

OBJECTIVES: To determine factors associated with bedside family presence in the PICU and to understand how individual factors interact as barriers to family presence. DESIGN: Mixed methods study. SETTING: Tertiary children's hospital PICU. SUBJECTS: Five hundred twenty-three children of less than 18 years enrolled in the Seattle Children's Hospital Outcomes Assessment Program from 2011 to 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Quantitative: Family was documented every 2 hours. Exposures included patient and illness characteristics and family demographic and socioeconomic characteristics. We used multivariable logistic regression to identify factors associated with presence of less than 80% and stratified results by self-reported race. Longer PICU length of stay (LOS), public insurance, and complex chronic conditions (C-CD) were associated with family presence of less than 80%. Self-reported race modified these associations; no factors were associated with lower bedside presence for White families, in contrast with multiple associations for non-White families including public insurance, C-CD, and longer LOS. Qualitative: Thematic analysis of social work notes for the 48 patients with family presence of less than 80% matched on age, LOS, and diagnosis to 48 patients with greater than or equal to 95% family presence. Three themes emerged: the primary caregiver's prior experiences with the hospital, relationships outside of the hospital, and additional stressors during the hospitalization affected bedside presence. CONCLUSIONS: We identified sociodemographic and illness factors associated with family bedside presence in the PICU. Self-reported race modified these associations, representing racism within healthcare. Family presence at the bedside may help identify families facing greater disparities in healthcare access.

Experiences of Alaska Native people living with burn injury and opportunities for health system strengthening.

BACKGROUND: Injuries are a leading cause of death and disability for Alaska Native (AN) people. Alaska Native Tribal Health Consortium (ANTHC) is supporting the development of a burn care system that includes a partnership between Alaska Native Medical Center (ANMC) in Anchorage, AK and UW Medicine Regional Burn Center at Harborview Medical Center (HMC) in Seattle, WA. We aimed to better understand the experiences of AN people with burn injuries across the care continuum to aid development of culturally appropriate care regionalization. METHODS: We performed focus groups with twelve AN people with burn injury and their caregivers. A multidisciplinary team of burn care providers, qualitative research experts, AN care coordinator, and AN cultural liaison led focus groups to elicit experiences across the burn care continuum. Transcripts were analyzed using a phenomenological approach and inductive coding to understand how AN people and families navigated the medical and community systems for burn care and areas for improvement. RESULTS: Three themes were identified: 1-Challenges with local burn care in remote communities including limited first aid, triage, pain management, and wound care, as well as long-distance transport to definitive care; 2-Divergence between cultural values and medical practices that generated mistrust in the medical system, isolation from their support systems, and recovery goals that were not aligned with their needs; 3-Difficulty accessing emotional health support and a survivor community that could empower their resilience. CONCLUSION: Participants reported modifiable barriers to culturally competent treatment for burn injuries among AN people. The findings can inform initiatives that leverage existing resources, including expansion of the Extension for Community Healthcare Outcomes (ECHO) telementoring program, promulgation of the Phoenix Society Survivors Offering Assistance in Recovery (SOAR) to AK, coordination of regionalized care to reduce time away from AK and provide more comfortable community reintegration, and define rehabilitation goals in terms that align with personal goals and subsistence lifestyle skills. Long-distance transport times are non-modifiable, but better pre-hospital care could be achieved by harnessing existing telehealth services and adapting principles of prolonged field care to allow for triage, initial care, and resuscitation in remote environments.

Structural Dynamics of a Common Mutagenic Oxidative DNA Lesion in Duplex DNA and during DNA Replication.

N6-(2-Deoxy-α,ß-d-erythro-pentofuranosyl)-2,6-diamino-4-hydroxy-5-formamido pyrimidine (Fapy•dG) is a prevalent form of genomic DNA damage. Fapy•dG is formed in greater amounts under anoxic conditions than the well-studied, chemically related 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodGuo). Fapy•dG is more mutagenic in mammalian cells than 8-oxodGuo. A distinctive property of Fapy•dG is facile epimerization, but prior works with Fapy•dG analogues have precluded determining its effect on chemistry. We present crystallographic characterization of natural Fapy•dG in duplex DNA and as the template base for DNA polymerase ß (Pol ß). Fapy•dG adopts the ß-anomer when base paired with cytosine but exists as a mixture of α- and ß-anomers when promutagenically base paired with adenine. Rotation about the bond between the glycosidic nitrogen atom and the pyrimidine ring is also affected by the opposing nucleotide. Sodium cyanoborohydride soaking experiments trap the ring-opened Fapy•dG, demonstrating that ring opening and epimerization occur in the crystalline state. Ring opening and epimerization are facilitated by propitious water molecules that are observed in the structures. Determination of Fapy•dG mutagenicity in wild type and Pol ß knockdown HEK 293T cells indicates that Pol ß contributes to G → T transversions but also suppresses G → A transitions. Complementary kinetic studies have determined that Fapy•dG promotes mutagenesis by decreasing the catalytic efficiency of dCMP insertion opposite Fapy•dG, thus reducing polymerase fidelity. Kinetic studies have determined that dCMP incorporation opposite the ß-anomer is ∼90 times faster than the α-anomer. This research identifies the importance of anomer dynamics, a feature unique to formamidopyrimidines, when considering the incorporation of nucleotides opposite Fapy•dG and potentially the repair of this structurally unusual lesion.

Integrated Photocatalytic Reduction and Oxidation of Perfluorooctanoic Acid by Metal-Organic Frameworks: Key Insights into the Degradation Mechanisms.

The high porosity and tunability of metal-organic frameworks (MOFs) have made them an appealing group of materials for environmental applications. However, their potential in the photocatalytic degradation of per- and polyfluoroalkyl substances (PFAS) has been rarely investigated. Hereby, we demonstrate that over 98.9% of perfluorooctanoic acid (PFOA) was degraded by MIL-125-NH2, a titanium-based MOF, in 24 h under Hg-lamp irradiation. The MOF maintained its structural integrity and porosity after three cycles, as indicated by its crystal structure, surface area, and pore size distribution. Based on the experimental results and density functional theory (DFT) calculations, a detailed reaction mechanism of the chain-shortening and H/F exchange pathways in hydrated electron (eaq-)-induced PFOA degradation were revealed. Significantly, we proposed that the coordinated contribution of eaq- and hydroxyl radical (•OH) is vital for chain-shortening, highlighting the importance of an integrated system capable of both reduction and oxidation for efficient PFAS degradation in water. Our results shed light on the development of effective and sustainable technologies for PFAS breakdown in the environment.

Components of Health-Related Quality of Life Most Affected Following Pediatric Critical Illness.

OBJECTIVES: To evaluate which individual elements of health-related quality of life contribute most to decline in overall health-related quality of life status following pediatric critical care. DESIGN: Retrospective cohort study. SETTING: Seattle Children's Hospital. PATIENTS: ICU patients age 1 month to 18 years admitted between December 2011 and February 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We assessed health-relatedquality of life decline from baseline to postdischarge (median, 6 wk) and determined the individual items of the Pediatric Quality of Life Inventory Infant Scales (< 2 yr) and Generic Core Scales (2-18 yr) with the highest prevalence of decline. We used multivariable regression to estimate the risk of decline in each of seven thematic categories by patient age, baseline health status, diagnosis, Pediatric Risk of Mortality score, and ICU length of stay. Decline from baseline health-related quality of life occurred in 22.5% of 539 patients. Items most commonly affected for infants less than 2 years were primarily emotional (cranky/crying, sleep, and self-soothing). Children 2-18 years most commonly experienced declines in physical functioning (play/exercise, lifting, and pain). Across the entire cohort, declines in categories of energy (31.5%), activity (31.0%), sleep (28.0%), and fear (24.7%) were most commonly endorsed. Risk of decline in each category varied with patient age, medical complexity, and diagnosis. CONCLUSIONS: Deconditioning, sleep, fear, and pain are important targets for intervention to improve health-related quality of life outcomes for critically ill children.

Reactive High-Valent Iron Intermediates in Enhancing Treatment of Water by Ferrate.

Efforts are being made to tune the reactivity of the tetraoxy anion of iron in the +6 oxidation state (FeVIO42-), commonly called ferrate, to further enhance its applications in various environmental fields. This review critically examines the strategies to generate highly reactive high-valent iron intermediates, FeVO43- (FeV) and FeIVO44- or FeIVO32- (FeIV) species, from FeVIO42-, for the treatment of polluted water with greater efficiency. Approaches to produce FeV and FeIV species from FeVIO42- include additions of acid (e.g., HCl), metal ions (e.g., Fe(III)), and reductants (R). Details on applying various inorganic reductants (R) to generate FeV and FeIV from FeVIO42- via initial single electron-transfer (SET) and oxygen-atom transfer (OAT) to oxidize recalcitrant pollutants are presented. The common constituents of urine (e.g., carbonate, ammonia, and creatinine) and different solids (e.g., silica and hydrochar) were found to accelerate the oxidation of pharmaceuticals by FeVIO42-, with potential mechanisms provided. The challenges of providing direct evidence of the formation of FeV/FeIV species are discussed. Kinetic modeling and density functional theory (DFT) calculations provide opportunities to distinguish between the two intermediates (i.e., FeIV and FeV) in order to enhance oxidation reactions utilizing FeVIO42-. Further mechanistic elucidation of activated ferrate systems is vital to achieve high efficiency in oxidizing emerging pollutants in various aqueous streams.

Patient-centered outcomes in pediatric continuous kidney replacement therapy: new morbidity and worsened functional status in survivors.

BACKGROUND: Ongoing measures to improve pediatric continuous kidney replacement therapy (CKRT) have lowered mortality rates, shifting the focus to survivor functional status. While septic acute kidney injury generates new morbidity in pediatric critically ill patients, acquired morbidities and functional status of CKRT population are unknown. We predicted that CKRT survivors are at risk for new morbidity and would have worse functional status at PICU discharge compared to baseline, and aimed to describe associated factors. METHODS: Retrospective cohort study over 24 months of CKRT patients surviving to PICU discharge in a quaternary children's hospital. Functional outcome was determined by Functional Status Scale (FSS). RESULTS: FSS scores were higher at PICU and hospital discharge compared to baseline. Of 45 CKRT survivors, 31 (69%) had worse FSS score at PICU discharge and 51% had new morbidity (≥3 increase in FSS); majority qualified as moderate to severe disability (FSS ≥10). Four patients (9%) had new tracheostomy, 3 (7%) were ventilator dependent, and 10 (22%) were dialysis dependent. Most (23/45, 51%) required outpatient rehabilitation. Cumulative days on sedation, controlled for illness severity, were independently associated with worse FSS at PICU discharge (aOR 25.18 (3.73, 169.92)). In adjusted analyses, duration of sedation was associated with new morbidity, while neurologic comorbidity, percent fluid overload at CKRT start, and nonrenal comorbidity were associated with moderate to severe disability at PICU discharge when controlled for baseline FSS. CONCLUSIONS: CKRT survivors, with new morbidity and worse functional outcomes at PICU discharge, are a newly described vulnerable population requiring targeted follow-up. Deliberate decrease of sedation exposure in patients with decreased clearance due to organ dysfunction needs to be studied as a modifiable risk factor.

Health-Related Quality of Life Following Delirium in the PICU.

OBJECTIVES: To evaluate whether delirium during pediatric critical illness is associated with post-discharge health-related quality of life. DESIGN: Retrospective cohort study. SETTING: Academic tertiary care center. PATIENTS: Children 1 month to 18 years old admitted to the PICU or cardiac ICU and enrolled in the Seattle Children's Hospital Outcomes Assessment Program. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Delirium was assessed twice daily using the Cornell Assessment of Pediatric Delirium; a score greater than or equal to 9 (with fluctuating level of arousal for children with developmental disability) indicated delirium. Baseline (pre-admission) and post-discharge health-related quality of life were assessed by the Pediatric Quality of Life Inventory (Mapi Research Trust, Lyon, France) or the Functional Status II-R (for children with developmental disability). Among 534 patients, delirium was common (44%), as was clinically important decline in health-related quality of life (≥ 4.5 points) from baseline to follow-up (22%), measured at median 6.6 weeks post-hospital discharge (interquartile range, 5.1-8.5). On univariate analysis, children with delirium had similar likelihood of health-related quality of life decline compared with those without (25.5% vs 19.7%; p = 0.1). Using multivariable logistic regression adjusting for age, medical complexity, predicted risk of mortality, admission diagnosis, receipt of noninvasive ventilation, hospital length of stay, time to follow-up, and parent age, delirium was independently associated with health-related quality of life decline among children assessed by the Pediatric Quality of Life Inventory (adjusted odds ratio, 2.0; 95% CI, 1.1-3.5). Among children evaluated with the Functional Status II-R, delirium was not independently associated with health-related quality of life decline (odds ratio, 1.4; 95% CI, 0.6-3.2). In both groups, longer time to follow-up was also independently associated with improvements in health-related quality of life. CONCLUSIONS: Delirium during the ICU stay is associated with decline in health-related quality of life from baseline to post-discharge follow-up among children assessed by the Pediatric Quality of Life Inventory, who were generally characterized by normal baseline cognitive function and less medical comorbidity. This association was not present among children assessed by the Functional Status II-R, potentially due to their higher overall risk of health-related quality of life decline, or other clinical differences that modify the effects of delirium in this group.

The association of severe pain experienced in the pediatric intensive care unit and postdischarge health-related quality of life: A retrospective cohort study.

BACKGROUND: Pain may be a modifiable risk factor for lower health-related quality of life after pediatric critical illness. AIM: To evaluate the association between severe pain experienced in the (pediatrc intensive care unit) and postdischarge health-related quality of life. METHODS: This was a retrospective cohort study. Children aged 1 month to 18 years admitted to the pediatric intensive care unit and enrolled in the Seattle Children's Hospital Outcomes Assessment Program were included. Pain was assessed every 2 h by bedside nursing staff using a behavioral pain scale or numeric pain scale. A day of severe pain was defined as a pediatric intensive care unit day with ≥25% of pain scores ≥7/10. Baseline (preadmission) and postdischarge (median 6 weeks) health-related quality of life was assessed by the Pediatric Quality of Life Inventory (PedsQL™) or the Stein Jessop Functional Status II-R (FS II-R, for children with developmental disability). The cohort was stratified by diagnosis category (surgical vs. medical), and associations were measured using linear regression models. RESULTS: Among 546 patients, 11.9% experienced ≥1 day of severe pain. In multivariable linear regression, each day of severe pain was independently associated with a lower postdischarge health-related quality of life score by 3.6 points (95% CI -6.3 to -0.9) adjusted for baseline health-related quality of life score, age, baseline cognitive function, days with multi-organ dysfunction, pediatric intensive care unit length of stay, and decline in overall function. This association was stronger among surgical patients than medical patients with each day of severe pain resulting in a lower postdischarge health-related quality of life score by 5.3 points (95% CI -9.6 to -0.9) versus 2.6 points (95% CI -5.8 to 0.6). Surgical patients had lower postdischarge emotional functioning than physical functioning subdomain scores. CONCLUSIONS: Children who experience severe pain in the pediatric intensive care unit have lower postdischarge health-related quality of life adjusting for baseline health-related quality of life, particularly among children who have undergone surgery. Attention to pain management may be important to improve postdischarge health-related quality of life.

Molecular and structural characterization of oxidized ribonucleotide insertion into DNA by human DNA polymerase ß.

During oxidative stress, inflammation, or environmental exposure, ribo- and deoxyribonucleotides are oxidatively modified. 8-Oxo-7,8-dihydro-2'-guanosine (8-oxo-G) is a common oxidized nucleobase whose deoxyribonucleotide form, 8-oxo-dGTP, has been widely studied and demonstrated to be a mutagenic substrate for DNA polymerases. Guanine ribonucleotides are analogously oxidized to r8-oxo-GTP, which can constitute up to 5% of the rGTP pool. Because ribonucleotides are commonly misinserted into DNA, and 8-oxo-G causes replication errors, we were motivated to investigate how the oxidized ribonucleotide is utilized by DNA polymerases. To do this, here we employed human DNA polymerase ß (pol ß) and characterized r8-oxo-GTP insertion with DNA substrates containing either a templating cytosine (nonmutagenic) or adenine (mutagenic). Our results show that pol ß has a diminished catalytic efficiency for r8-oxo-GTP compared with canonical deoxyribonucleotides but that r8-oxo-GTP is inserted mutagenically at a rate similar to those of other common DNA replication errors (i.e. ribonucleotide and mismatch insertions). Using FRET assays to monitor conformational changes of pol ß with r8-oxo-GTP, we demonstrate impaired pol ß closure that correlates with a reduced insertion efficiency. X-ray crystallographic analyses revealed that, similar to 8-oxo-dGTP, r8-oxo-GTP adopts an anti conformation opposite a templating cytosine and a syn conformation opposite adenine. However, unlike 8-oxo-dGTP, r8-oxo-GTP did not form a planar base pair with either templating base. These results suggest that r8-oxo-GTP is a potential mutagenic substrate for DNA polymerases and provide structural insights into how r8-oxo-GTP is processed by DNA polymerases.

Structure and function relationships in mammalian DNA polymerases.

DNA polymerases are vital for the synthesis of new DNA strands. Since the discovery of DNA polymerase I in Escherichia coli, a diverse library of mammalian DNA polymerases involved in DNA replication, DNA repair, antibody generation, and cell checkpoint signaling has emerged. While the unique functions of these DNA polymerases are differentiated by their association with accessory factors and/or the presence of distinctive catalytic domains, atomic resolution structures of DNA polymerases in complex with their DNA substrates have revealed mechanistic subtleties that contribute to their specialization. In this review, the structure and function of all 15 mammalian DNA polymerases from families B, Y, X, and A will be reviewed and discussed with special emphasis on the insights gleaned from recently published atomic resolution structures.

A guardian residue hinders insertion of a Fapy•dGTP analog by modulating the open-closed DNA polymerase transition.

4,6-Diamino-5-formamidopyrimidine (Fapy•dG) is an abundant form of oxidative DNA damage that is mutagenic and contributes to the pathogenesis of human disease. When Fapy•dG is in its nucleotide triphosphate form, Fapy•dGTP, it is inefficiently cleansed from the nucleotide pool by the responsible enzyme in Escherichia coli MutT and its mammalian homolog MTH1. Therefore, under oxidative stress conditions, Fapy•dGTP could become a pro-mutagenic substrate for insertion into the genome by DNA polymerases. Here, we evaluated insertion kinetics and high-resolution ternary complex crystal structures of a configurationally stable Fapy•dGTP analog, ß-C-Fapy•dGTP, with DNA polymerase ß. The crystallographic snapshots and kinetic data indicate that binding of ß-C-Fapy•dGTP impedes enzyme closure, thus hindering insertion. The structures reveal that an active site residue, Asp276, positions ß-C-Fapy•dGTP so that it distorts the geometry of critical catalytic atoms. Removal of this guardian side chain permits enzyme closure and increases the efficiency of ß-C-Fapy•dG insertion opposite dC. These results highlight the stringent requirements necessary to achieve a closed DNA polymerase active site poised for efficient nucleotide incorporation and illustrate how DNA polymerase ß has evolved to hinder Fapy•dGTP insertion.

The Impact of Rapid Exome Sequencing on Medical Management of Critically Ill Children.

OBJECTIVES: To evaluate the clinical usefulness of rapid exome sequencing (rES) in critically ill children with likely genetic disease using a standardized process at a single institution. To provide evidence that rES with should become standard of care for this patient population. STUDY DESIGN: We implemented a process to provide clinical-grade rES to eligible children at a single institution. Eligibility included (a) recommendation of rES by a consulting geneticist, (b) monogenic disorder suspected, (c) rapid diagnosis predicted to affect inpatient management, (d) pretest counseling provided by an appropriate provider, and (e) unanimous approval by a committee of 4 geneticists. Trio exome sequencing was sent to a reference laboratory that provided verbal report within 7-10 days. Clinical outcomes related to rES were prospectively collected. Input from geneticists, genetic counselors, pathologists, neonatologists, and critical care pediatricians was collected to identify changes in management related to rES. RESULTS: There were 54 patients who were eligible for rES over a 34-month study period. Of these patients, 46 underwent rES, 24 of whom (52%) had at least 1 change in management related to rES. In 20 patients (43%), a molecular diagnosis was achieved, demonstrating that nondiagnostic exomes could change medical management in some cases. Overall, 84% of patients were under 1 month old at rES request and the mean turnaround time was 9 days. CONCLUSIONS: rES testing has a significant impact on the management of critically ill children with suspected monogenic disease and should be considered standard of care for tertiary institutions who can provide coordinated genetics expertise.

A Case of Adjacent, Clonally Distinct Borderline Melanocytic Tumors on the Arm.

Atypical Spitz tumor (AST) is a melanocytic proliferation that shares histopathologic features of Spitz nevus and spitzoid melanoma. Distinction of AST from spitzoid melanoma is critical because the majority of ASTs will follow an indolent course. Array-based comparative genomic hybridization (aCGH) has been suggested as a potential tool for evaluating malignant potential in spitzoid tumors. We present a case of a 52-year-old woman with an AST in which aCGH was crucial in guiding correct diagnosis and management. The patient first presented with a flesh-colored papule on her arm that was changing color. Biopsy revealed a dermal nevoid melanocytic tumor of indeterminate histopathology, favored to be a severely atypical nevus. The tumor was excised. One year later, another flesh-colored papule proximal to the excision site of the first tumor was biopsied and showed a predominantly dermal atypical spitzoid melanocytic proliferation with a differential diagnosis of AST versus spitzoid melanoma. Recurrent or metastatic melanoma was also a concern given proximity to the previous excision site. Molecular analysis of both lesions by aCGH revealed distinct molecular signatures, supporting the 2 tumors to be clonally unrelated. Furthermore, the new tumor displayed limited evidence of genomic instability, supporting classification as an AST with predicted indolent behavior. This case highlights the utility of aCGH in evaluating borderline melanocytic lesions, including assessment of malignant potential in ASTs, and clonality analysis to assist in exclusion of metastatic disease.

Capturing a mammalian DNA polymerase extending from an oxidized nucleotide.

The oxidized nucleotide, 8-oxo-7,8-dihydro-2΄-deoxyguanosine (8-oxoG), is one of the most abundant DNA lesions. 8-oxoG plays a major role in tumorigenesis and human disease. Biological consequences of 8-oxoG are mediated in part by its insertion into the genome, making it essential to understand how DNA polymerases handle 8-oxoG. Insertion of 8-oxoG is mutagenic when opposite adenine but not when opposite cytosine. However, either result leads to DNA damage at the primer terminus (3΄-end) during the succeeding insertion event. Extension from DNA damage at primer termini remains poorly understood. Using kinetics and time-lapse crystallography, we evaluated how a model DNA polymerase, human polymerase ß, accommodates 8-oxoG at the primer terminus opposite cytosine and adenine. Notably, extension from the mutagenic base pair is favored over the non-mutagenic base pair. When 8-oxoG is at the primer terminus opposite cytosine, DNA centric changes lead to a clash between O8 of 8-oxoG and the phosphate backbone. Changes in the extension reaction resulting from the altered active site provide evidence for a stabilizing interaction between Arg254 and Asp256 that serves an important role during DNA synthesis reactions. These results provide novel insights into the impact of damage at the primer terminus on genomic stability and DNA synthesis.

An updated assessment of social media usage by dermatology journals and organizations.

Despite the increasing prevalence of social media usage, the activity of dermatology journals and professional and patient-centered organizations on top social media platforms has not been investigated since 2012. We investigated a total of 124 dermatology journals, 242 professional organizations, and 78 patient-centered organizations to assess their presence and popularity on social media. Searches were conducted to identify journals and organizations on Facebook and Twitter. Similar searches were done for organizations on LinkedIn. The number of Facebook likes, Twitter followers, and LinkedIn followers of the dermatological entities were quantified. There were 22 (17.7%) dermatology journals active on Facebook and 21 (16.9%) on Twitter. Amongst the professional organizations, 114 (47.1%) were on Facebook, 69 (28.5%) on Twitter, and 50 (20.7%) on LinkedIn. In comparison, 68 (87.2%) patient-centered organizations were on Facebook, 56 (71.8%) on Twitter, and 56 (71.8%) on LinkedIn. Our results demonstrate that the popularity of dermatology journals and professional and patient-centered organizations on top social networking sites has grown markedly since 2012. Although the number of dermatology journals on social media has increased since 2012, their presence continues to trail behind professional and patient-centered dermatological organizations, suggesting underutilization of a valuable resource.

Structures of a DNA Polymerase Inserting Therapeutic Nucleotide Analogues.

Members of the nucleoside analogue class of cancer therapeutics compete with canonical nucleotides to disrupt numerous cellular processes, including nucleotide homeostasis, DNA and RNA synthesis, and nucleotide metabolism. Nucleoside analogues are triphosphorylated and subsequently inserted into genomic DNA, contributing to the efficacy of therapeutic nucleosides in multiple ways. In some cases, the altered base acts as a mutagen, altering the DNA sequence to promote cellular death; in others, insertion of the altered nucleotide triggers DNA repair pathways, which produce lethal levels of cytotoxic intermediates such as single and double stranded DNA breaks. As a prerequisite to many of these biological outcomes, the modified nucleotide must be accommodated in the DNA polymerase active site during nucleotide insertion. Currently, the molecular contacts that mediate DNA polymerase insertion of modified nucleotides remain unknown for multiple therapeutic compounds, despite decades of clinical use. To determine how modified bases are inserted into duplex DNA, we used mammalian DNA polymerase ß (pol ß) to visualize the structural conformations of four therapeutically relevant modified nucleotides, 6-thio-2'-deoxyguanosine-5'-triphosphate (6-TdGTP), 5-fluoro-2'-deoxyuridine-5'-triphosphate (5-FdUTP), 5-formyl-deoxycytosine-5'-triphosphate (5-FodCTP), and 5-formyl-deoxyuridine-5'-triphosphate (5-FodUTP). Together, the structures reveal a pattern in which the modified nucleotides utilize Watson-Crick base pairing interactions similar to that of unmodified nucleotides. The nucleotide modifications were consistently positioned in the major groove of duplex DNA, accommodated by an open cavity in pol ß. These results provide novel information for the rational design of new therapeutic nucleoside analogues and a greater understanding of how modified nucleotides are tolerated by polymerases.