Single cell transcriptomics reveals early photoreceptor states, cell-specific transcript isoforms, and cancer-predisposing features.

Human cone photoreceptors differ from rods and serve as the retinoblastoma cell-of-origin. Here, we used deep full-length single-cell RNA-sequencing to distinguish post-mitotic cone and rod developmental states and cone-specific features that contribute to retinoblastomagenesis. The analyses revealed early post-mitotic cone- and rod-directed populations characterized by higher THRB or NRL regulon activities, an immature photoreceptor precursor population with concurrent cone and rod gene and regulon expression, and distinct early and late cone and rod maturation states distinguished by maturation-associated declines in RAX regulon activity. Unexpectedly, both L/M cone and rod precursors co-expressed NRL and THRB RNAs, yet they differentially expressed functionally antagonistic NRL isoforms and prematurely terminated THRB transcripts. Early L/M cone precursors exhibited successive expression of lncRNAs along with MYCN, which composed the seventh most L/M-cone-specific regulon, and SYK, which contributed to the early cone precursors' proliferative response to RB1 loss. These findings reveal previously unrecognized photoreceptor precursor states and a role for early cone-precursor-intrinsic SYK expression in retinoblastoma initiation.

Retinoblastoma Outcomes in the Americas: A Prospective Analysis of 491 Children With Retinoblastoma From 23 American Countries.

PURPOSE: Globally, disparities exist in retinoblastoma treatment outcomes between high- and low-income countries, but independent analysis of American countries is lacking. We report outcomes of American retinoblastoma patients and explore factors associated with survival and globe salvage. DESIGN: Subanalysis of prospective cohort study data. METHODS: Multicenter analysis at 57 American treatment centers in 23 countries of varying economic levels (low income [LIC], lower-middle income [LMIC], upper-middle income [UMIC], and high income [HIC]) of 491 treatment-naïve retinoblastoma patients diagnosed in 2017 and followed through 2020. Survival and globe salvage rates analyzed with Kaplan-Meier analysis and Cox proportional hazard models. RESULTS: Of patients, 8 (1.6%), 58 (11.8%), 235 (47.9%), and 190 (38.7%) were from LIC, LMIC, UMIC, and HIC groups, respectively. Three-year survival rates in LICs were 60.0% (95% confidence interval [CI] 12.6-88.2) compared with 99.2% (95% CI 94.6%-99.9%) in HICs. Death was less likely in patients >4 years of age (vs ≤4 years, HR = 0.45 [95% CI 0.27-0.78], P = .048). Patients with more advanced tumors (eg, cT3 vs cT1, HR = 4.65 × 109 [95% CI 1.25 × 109-1.72 × 1010], P < .001) and females (vs males, HR = 1.98 [95% CI 1.27-3.10], P = .04) were more likely to die. Three-year globe salvage rates were 13.3% (95% CI 5.1%-25.6%) in LMICs and 46.2% (95% CI 38.8%-53.3%) in HICs. At 3 years, 70.1% of cT1 eyes (95% CI 54.5%-81.2%) vs 8.9% of cT3 eyes (95% CI 5.5%-13.3%) were salvaged. Advanced tumor stage was associated with higher enucleation risk (eg, cT3 vs cT1, subhazard ratio = 4.98 [95% CI 2.36-10.5], P < .001). CONCLUSIONS: Disparities exist in survival and globe salvage in American countries based on economic level and tumor stage demonstrating a need for childhood cancer programs.

Aqueous Humor Liquid Biopsy as a Companion Diagnostic for Retinoblastoma: Implications for Diagnosis, Prognosis, and Therapeutic Options: Five Years of Progress.

PURPOSE: To define the prospective use of the aqueous humor (AH) as a molecular diagnostic and prognostic liquid biopsy for retinoblastoma (RB). METHODS: This is a prospective, observational study wherein an AH liquid biopsy is performed at diagnosis and longitudinally through therapy for patients with RB. Tumor-derived cell-free DNA is isolated and sequenced for single nucleotide variant analysis of the RB1 gene and detection of somatic copy number alterations (SCNAs). The SCNAs are used to determine tumor fraction (TFx). Specific SCNAs, including 6p gain and focal MycN gain, along with TFx, are prospectively correlated with intraocular tumor relapse, response to therapy, and globe salvage. RESULTS: A total of 26 eyes of 21 patients were included with AH taken at diagnosis. Successful ocular salvage was achieved in 19 of 26 (73.1%) eyes. Mutational analysis of 26 AH samples identified 23 pathogenic RB1 variants and 2 focal RB1 deletions; variant allele fraction ranged from 30.5% to 100% (median 93.2%). At diagnosis, SCNAs were detectable in 17 of 26 (65.4%) AH samples. Eyes with 6p gain and/or focal MycN gain had significantly greater odds of poor therapeutic outcomes (odds ratio = 6.75, 95% CI = 1.06-42.84, P = .04). Higher AH TFx was observed in eyes with vitreal progression (TFx = 46.0% ± 40.4) than regression (22.0 ± 29.1; difference: -24.0; P = .049). CONCLUSIONS: Establishing an AH liquid biopsy for RB is aimed at addressing (1) our inability to biopsy tumor tissue and (2) the lack of molecular biomarkers for intraocular prognosis. Current management decisions for RB are made based solely on clinical features without objective molecular testing. This prognostic study shows great promise for using AH as a companion diagnostic. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Multicentre analysis of nucleic acid quantification using aqueous humour liquid biopsy in uveal melanoma: implications for clinical testing.

OBJECTIVE: Uveal melanoma (UM) tumour biopsy is limited by size and intratumour heterogeneity. We explored the potential of aqueous humour (AH) liquid biopsy for UM by quantifying analytes in samples collected at diagnosis and after brachytherapy to look for clinical correlations with tumour features. DESIGN: Case-series study. PARTICIPANTS: Sixty-six UM patients and 16 control subjects from a tertiary care hospital. METHODS: The study included 119 UM AH samples and 16 control samples analyzed for unprocessed analytes (i.e., dsDNA, miRNA, and protein) using Qubit fluorescence assays. RESULTS: Analytes were widely quantifiable among available UM AH samples (dsDNA: 94.1%; miRNA: 88.0%; protein: 95.2%) at significantly higher concentrations than among control samples (dsDNA, p = 0.008; miRNA, p < 0.0001; protein, p = 0.007). In samples taken at diagnosis, concentrations were higher at more advanced American Joint Cancer Commission stages; when comparing most advanced stage III with least advanced stage I, median dsDNA was 4 times greater (p < 0.0001), miRNA was 2 times greater (p = 0.001), and protein was 3 times greater (p < 0.0001). Analytes were quantifiable in >70% of diagnostic samples from eyes with tumours <2 mm tall. Height had a positive association with diagnostic analyte concentrations (dsDNA: R = 0.43, p = 0.0007; miRNA: R = 0.35, p = 0.01; protein: R = 0.39, p = 0.005). Samples taken after brachytherapy showed significantly higher concentrations than diagnostic samples (p < 0.01 for all). CONCLUSIONS: UM AH is a rich repository of analytes. Samples from eyes with more advanced stage and larger tumours had higher concentrations, though analytes also were quantifiable in eyes with smaller, less advanced tumours. Future analysis of AH analytes may be informative in the pursuit of personalized UM treatments.

A Multicenter Analysis of Nucleic Acid Quantification Using Aqueous Humor Liquid Biopsy in Retinoblastoma: Implications for Clinical Testing.

Purpose: Retinoblastoma (RB) is most often diagnosed with clinical features and not diagnosed with tumor biopsy. This study describes tumor-derived analyte concentrations from aqueous humor (AH) liquid biopsy and its use in clinical assays. Design: Case series study. Participants: Sixty-two RB eyes from 55 children and 14 control eyes from 12 children from 4 medical centers. Methods: This study included 128 RB AH samples including: diagnostic (DX) samples, samples from eyes undergoing treatment (TX), samples after completing treatment (END), and during bevacizumab injection for radiation therapy after completing RB treatment (BEV). Fourteen-control AH were analyzed for unprocessed analytes (double-stranded DNA [dsDNA], single-stranded DNA [ssDNA], micro-RNA [miRNA], RNA, and protein) with Qubit fluorescence assays. Double-stranded DNA from 2 RB AH samples underwent low-pass whole-genome sequencing to detect somatic copy number alterations. Logistic regression was used to predict disease burden given analyte concentrations. Main Outcome Measures: Unprocessed analyte (dsDNA, ssDNA, miRNA, RNA and protein) concentrations. Results: Results revealed dsDNA, ssDNA, miRNA, and proteins, but not RNA, were quantifiable in most samples (up to 98%) with Qubit fluorescence assays. Median dsDNA concentration was significantly higher in DX (3.08 ng/µl) compared to TX (0.18 ng/µl; P < 0.0001) at an order of 17 times greater and 20 times greater than END samples (0.15 ng/µl; P = 0.001). Using logistic regression, nucleic acid concentrations were useful in predicting higher versus lower RB disease burden. Retinoblastoma somatic copy number alterations were identified in a TX, but not in a BEV sample, indicating the correlation with RB activity. Conclusions: Aqueous humor liquid biopsy in RB is a high-yield source of dsDNA, ssDNA, miRNA, and protein. Diagnostic samples are most useful for RB 1 gene mutational analyses. Genomic analysis may be more informative of tumor activity status than quantification alone and can be performed even with smaller analyte concentrations obtained from TX samples. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

Reliability of telemedicine for real-time paediatric ophthalmology consultations.

BACKGROUND/AIMS: To assess the accuracy of real-time telemedicine to diagnose and manage paediatric eye conditions. METHODS: Design: Prospective, non-inferiority study analysing agreement in diagnoses and management plans between telemedicine and in-person examinations. Setting: Paediatric ophthalmology clinic. Population: Children 0-17 years, English-speaking or Spanish-speaking, able to participate in age-appropriate manner, either previously seen by the optometrist and required ophthalmology referral or newly referred from outside source. Procedures: Paediatric optometrist conducted examinations using digital equipment and streamed live to a paediatric ophthalmologist who recorded diagnoses and management plans, then re-examined patients in-person. Subjects were masked to the fact they would see the ophthalmologist in-person, same-day. Main outcome measures: Discrepancy in management plan or diagnosis between telemedicine and in-person examinations. Non-inferiority threshold was <1.5% for management plan or <15% for diagnosis discrepancies. RESULTS: 210 patients participated in 348 examinations. 131 (62.4%) had strabismus as primary diagnosis. In these patients, excellent and almost perfect agreement was observed for angle measurements (intraclass correlation coefficients=0.98-1.00) and disease categorisation (kappa=0.94-1.00) (p<0.0001 in all cases). No primary diagnoses changed, and no management plans changed following in-person examination. 54/55 patients who consented for surgery at the initial visit did so while masked to receiving an in-person examination. Families felt comfortable with the quality of the telemedicine examination (98.5%) and would participate in another in the future (97.1%). CONCLUSION: Paediatric ophthalmic conditions can be reliably diagnosed and managed via telemedicine. Access for underserved populations may be improved by collaboration between ophthalmologists and optometrists using this technology.

The Effects of Breastfeeding on Retinoblastoma Development: Results from an International Multicenter Retinoblastoma Survey.

The protective effects of breastfeeding on various childhood malignancies have been established but an association has not yet been determined for retinoblastoma (RB). We aimed to further investigate the role of breastfeeding in the severity of nonhereditary RB development, assessing relationship to (1) age at diagnosis, (2) ocular prognosis, measured by International Intraocular RB Classification (IIRC) or Intraocular Classification of RB (ICRB) group and success of eye salvage, and (3) extraocular involvement. Analyses were performed on a global dataset subgroup of 344 RB patients whose legal guardian(s) consented to answer a neonatal questionnaire. Patients with undetermined or mixed feeding history, family history of RB, or sporadic bilateral RB were excluded. There was no statistically significant difference between breastfed and formula-fed groups in (1) age at diagnosis (p = 0.20), (2) ocular prognosis measures of IIRC/ICRB group (p = 0.62) and success of eye salvage (p = 0.16), or (3) extraocular involvement shown by International Retinoblastoma Staging System (IRSS) at presentation (p = 0.74), lymph node involvement (p = 0.20), and distant metastases (p = 0.37). This study suggests that breastfeeding neither impacts the sporadic development nor is associated with a decrease in the severity of nonhereditary RB as measured by age at diagnosis, stage of disease, ocular prognosis, and extraocular spread. A further exploration into the impact of diet on children who develop RB is warranted.

Comprehensive Somatic Copy Number Analysis Using Aqueous Humor Liquid Biopsy for Retinoblastoma.

Aqueous humor (AH) liquid biopsy has been established as a surrogate tumor biopsy for retinoblastoma (RB). Previous AH studies have focused on highly recurrent RB somatic copy number alterations (SCNAs) including gain of 1q, 2p, 6p, and loss of 13q and 16q. In this retrospective study, we provide a comprehensive, whole-genome analysis of RB SCNAs and evaluate associated clinical features for 68 eyes of 64 RB patients from whom AH was obtained between December 2014 and October 2020. Shallow whole-genome sequencing of AH cell-free DNA was performed to assess for SCNAs. The prevalence of specific non-highly recurrent SCNAs, such as 20q gain and 8p loss, differed between primarily and secondarily enucleated eyes. Increases in chromosomal instability predict more advanced seeding morphology (p = 0.015); later age of diagnosis (p < 0.0001); greater odds of an endophytic tumor growth pattern (without retinal detachment; p = 0.047); tumor heights >10 mm (p = 0.09); and containing 6p gain, a biomarker of poor ocular prognosis (p = 0.004). The AH liquid biopsy platform is a high-yield method of whole-genome RB SCNA analysis, and SCNAs are associated with numerous clinical findings in RB eyes. Prospective analyses are encouraged to further elucidate the clinical relevance of specific SCNAs in RB.

Establishing the Clinical Utility of ctDNA Analysis for Diagnosis, Prognosis, and Treatment Monitoring of Retinoblastoma: The Aqueous Humor Liquid Biopsy.

Because direct tumor biopsy is prohibited for retinoblastoma (RB), eye-specific molecular biomarkers are not used in clinical practice for RB. Recently, we demonstrated that the aqueous humor (AH) is a rich liquid biopsy source of cell-free tumor DNA. Herein, we detail clinically-relevant molecular biomarkers from the first year of prospective validation data. Seven eyes from 6 RB patients who had AH sampled at diagnosis and throughout therapy with ≥12 months of follow-up were included. Cell-free DNA (cfDNA) from each sample was isolated and sequenced to assess genome-wide somatic copy number alterations (SCNAs), followed by targeted resequencing for pathogenic variants using a RB1 and MYCN custom hybridization panel. Tumoral genomic information was detected in 100% of diagnostic AH samples. Of the seven diagnostic AH samples, 5/7 were positive for RB SCNAs. Mutational analysis identified RB1 variants in 5/7 AH samples, including the 2 samples in which no SCNAs were detected. Two eyes failed therapy and required enucleation; both had poor prognostic biomarkers (chromosome 6p gain or MYCN amplification) present in the AH at the time of diagnosis. In the context of previously established pre-analytical, analytical, and clinical validity, this provides evidence for larger, prospective studies to further establish the clinical utility of the AH liquid biopsy and its applications to precision oncology for RB.

Chromosome 6p Amplification in Aqueous Humor Cell-Free DNA Is a Prognostic Biomarker for Retinoblastoma Ocular Survival.

Aqueous humor contains tumor-derived cell-free DNA (cfDNA) and can serve as a liquid biopsy for retinoblastoma. We previously associated somatic copy-number alteration (SCNA) 6p gain with a 10-fold increased risk of enucleation. Here we provide a 2-year update to further explore 6p gain as a prognostic biomarker for ocular survival. Patients diagnosed with retinoblastoma from December 2014 to July 2019 from whom aqueous humor was sampled were included. cfDNA was extracted and shallow whole-genome sequencing performed to identify highly recurrent retinoblastoma SCNAs (gain of 1q, 2p, 6p, loss of 13q, 16q). 116 aqueous humor samples from 50 eyes of 46 patients were included: 27 eyes were salvaged, 23 were enucleated. Highly recurrent retinoblastoma SCNAs were found in 66% eyes. 6p gain was the most prevalent SCNA (50% eyes). It was particularly more prevalent in enucleated eyes (73.9%) than in salvaged eyes (29.6%; P = 0.004). 6p gain in aqueous humor cfDNA portended nearly 10-fold increased odds of enucleation (OR = 9.87; 95% confidence interval = 1.75-55.65; P = 0.009). In the enucleated eyes, 6p gain was associated with aggressive histopathologic features, including necrosis, higher degrees of anaplasia, and focal invasion of ocular structures. With extended follow-up and nearly double the aqueous humor samples, we continue to demonstrate 6p gain as a potential prognostic biomarker for retinoblastoma. IMPLICATIONS: Aqueous humor is a high-yield source of tumor-derived DNA in retinoblastoma eyes. Detection of 6p gain in the aqueous humor allows for targeted, patient-centered therapies based on this molecular prognostic marker. Prospective, multicenter studies with aqueous humor sampled from all eyes at diagnosis are warranted to validate these findings.

VISUAL AND ANATOMIC OUTCOMES OF PEDIATRIC ENDOSCOPIC VITRECTOMY IN 326 CASES.

PURPOSE: To report on the indications, outcomes, and complications of endoscopic vitrectomy in a large cohort of pediatric vitreoretinal patients. METHODS: This is a retrospective interventional case series consisting of 244 eyes of 211 patients aged 18 years or younger undergoing a total of 326 endoscopic vitrectomies from 2008 to 2017. A 23-gauge vitrectomy was performed with use of a 19-gauge endoscope. RESULTS: Two hundred and eleven patients with a mean age of 7.5 years (range: 0-18 years) and median follow-up since last surgery of 28 months (range: 3 months-8.7 years) were included. The most common indication for endoscopic vitrectomy was retinal detachment (234/326; 72%) with proliferative vitreoretinopathy (162/234; 69%). Other diagnoses included trauma (25%), retinopathy of prematurity (15%), and glaucoma (9%). Twenty-five percent of surgeries (80/326) were performed on eyes with significant corneal opacities. Retinal reattachment was achieved in 67% of eyes with retinal detachment (119/178). Visual acuity improved in 26% of retinal detachment eyes versus 53% of nonretinal detachment eyes (P = 0.005). Surgical complications included band keratopathy (15%), hypotony (8%), cataract (7%), and elevated intraocular pressure (3%). CONCLUSION: In this large series of pediatric endoscopic vitreoretinal surgeries, anatomic outcomes and complication rates were comparable with previous studies.

Developmental stage-specific proliferation and retinoblastoma genesis in RB-deficient human but not mouse cone precursors.

Most retinoblastomas initiate in response to the inactivation of the RB1 gene and loss of functional RB protein. The tumors may form with few additional genomic changes and develop after a premalignant retinoma phase. Despite this seemingly straightforward etiology, mouse models have not recapitulated the genetic, cellular, and stage-specific features of human retinoblastoma genesis. For example, whereas human retinoblastomas appear to derive from cone photoreceptor precursors, current mouse models develop tumors that derive from other retinal cell types. To investigate the basis of the human cone-specific oncogenesis, we compared developmental stage-specific cone precursor responses to RB loss in human and murine retina cultures and in cone-specific Rb1-knockout mice. We report that RB-depleted maturing (ARR3+) but not immature (ARR3-) human cone precursors enter the cell cycle, proliferate, and form retinoblastoma-like lesions with Flexner-Wintersteiner rosettes, then form low or nonproliferative premalignant retinoma-like lesions with fleurettes and p16INK4A and p130 expression, and finally form highly proliferative retinoblastoma-like masses. In contrast, in murine retina, only RB-depleted immature (Arr3-) cone precursors entered the cell cycle, and they failed to progress from S to M phase. Moreover, whereas intrinsically highly expressed MDM2 and MYCN contribute to RB-depleted maturing (ARR3+) human cone precursor proliferation, ectopic MDM2 and Mycn promoted only immature (Arr3-) murine cone precursor cell-cycle entry. These findings demonstrate that developmental stage-specific as well as species- and cell type-specific features sensitize to RB1 inactivation and reveal the human cone precursors' capacity to model retinoblastoma initiation, proliferation, premalignant arrest, and tumor growth.

Porous orbital implant after enucleation in retinoblastoma patients: indications and complications.

This study aims to identify risk factors associated with complications in retinoblastoma patients following primary and secondary enucleations with porous implant placement. A retrospective case-control study was performed between 2010 and 2015. Data pertaining to subjects' demographics, medical history, clinical, and pathological findings, implant characteristics and complications were collected. The analysis included 103 eyes of 101 patients age 27.8 ± 21.9 months undergoing enucleation for retinoblastoma. Postoperatively, 19/103 (18%) eyes developed exposure, extrusion, or hematoma requiring subsequent surgery. Exposure was the most common postoperative complication (12/19, 63%). Age at enucleation 24 months or younger, Hispanic ethnicity, female gender, and intravenous chemotherapy prior to enucleation were associated with increased odds of implant complications. In contrast, patients who were given intravitreal melphalan (IM), subtenons carboplatin (SC), or external beam radiation therapy (EBRT) did not demonstrate an increased risk of complications. In this cohort of retinoblastoma patients undergoing primary or secondary enucleation with porous implants, implant exposure was the most common postoperative complication. Our findings suggest that female gender, Hispanic ethnicity, age at enucleation 24 months or younger, and intravenous chemotherapy prior to enucleation may increase the risk of complications.

SKP2 Activation by Thyroid Hormone Receptor ß2 Bypasses Rb-Dependent Proliferation in Rb-Deficient Cells.

Germline RB1 mutations strongly predispose humans to cone precursor-derived retinoblastomas and strongly predispose mice to pituitary tumors, yet shared cell type-specific circuitry that sensitizes these different cell types to the loss of RB1 has not been defined. Here we show that the cell type-restricted thyroid hormone receptor isoform TRß2 sensitizes to RB1 loss in both settings by antagonizing the widely expressed and tumor-suppressive TRß1. TRß2 promoted expression of the E3 ubiquitin ligase SKP2, a critical factor for RB1-mutant tumors, by enabling EMI1/FBXO5-dependent inhibition of SKP2 degradation. In RB1 wild-type neuroblastoma cells, endogenous Rb or ectopic TRß2 was required to sustain SKP2 expression as well as cell viability and proliferation. These results suggest that in certain contexts, Rb loss enables TRß1-dependent suppression of SKP2 as a safeguard against RB1-deficient tumorigenesis. TRß2 counteracts TRß1, thus disrupting this safeguard and promoting development of RB1-deficient malignancies. Cancer Res; 77(24); 6838-50. ©2017 AACR.

Predictive overbooking and active recruitment increases uptake of endoscopy appointments among African American patients.

BACKGROUND AND AIMS: Use of GI endoscopy is historically lower in nonwhite ethnic and racial groups compared with whites. These disparities are multifactorial but likely contribute to differences in GI clinical outcomes. We sought to improve endoscopy uptake overall and in minorities by predictive overbooking and active recruitment in a hospital-based GI clinic. METHODS: From January to October 2014, we alternated between traditional booking for Veterans Affairs Healthcare Network patients with a physician recommendation for endoscopy and active recruitment of patients to fill projected open endoscopy appointment slots. On intervention weeks, patients attending a GI clinic were given the opportunity to "fast track" to an endoscopy appointment on short notice. During control weeks, patients were not actively recruited. We compared uptake of endoscopy appointments in both groups and performed logistic regression to determine predictors of participation in fast-track active recruitment. RESULTS: During fast-track active recruitment for endoscopy, the clinic recruited an additional 111 patients for endoscopy over passive recruitment, including 46 African Americans (41.4%). In a logistic regression model controlling for demographic and clinical characteristics, African Americans were twice as likely (adjusted OR, 1.99; 95% CI, 1.26-3.17) than whites to participate in the fast-track option for recommended endoscopy. CONCLUSIONS: Interventions to actively recruit patients for endoscopy increased the overall percentage of GI clinic patients undergoing endoscopy and disproportionately improved endoscopy appointment uptake in African Americans.

Preventing Endoscopy Clinic No-Shows: Prospective Validation of a Predictive Overbooking Model.

OBJECTIVES: Patient absenteeism for scheduled visits and procedures ("no-show") occurs frequently in healthcare systems worldwide, resulting in treatment delays and financial loss. To address this problem, we validated a predictive overbooking system that identifies patients at high risk for missing scheduled gastrointestinal endoscopy procedures ("no-shows" and cancellations), and offers their appointments to other patients on short notice. METHODS: We prospectively tested a predictive overbooking system at a Veterans Administration outpatient endoscopy clinic over a 34-week period, alternating between traditional booking and predictive overbooking methods. For the latter, we assigned a no-show risk score to each scheduled patient, utilizing a previously developed logistic regression model built with electronic health record data. To compare booking methods, we measured service utilization-defined as the percentage of daily total clinic capacity occupied by patients-and length of clinic workday. RESULTS: Compared to typical booking, predictive overbooking resulted in nearly all appointment slots being filled-2.5 slots available during control weeks vs. 0.35 slots during intervention weeks, t(161)=4.10, P=0.0001. Service utilization increased from 86% during control weeks to 100% during intervention weeks, allowing 111 additional patients to undergo procedures. Physician and staff overages were more common during intervention weeks, but less than anticipated (workday length of 7.84 h (control) vs. 8.31 h (intervention), t(161)=2.28, P=0.02). CONCLUSIONS: Predictive overbooking may be used to maximize endoscopy scheduling. Future research should focus on adapting the model for use in primary care and specialty clinics.

Association of the OPRM1 Variant rs1799971 (A118G) with Non-Specific Liability to Substance Dependence in a Collaborative de novo Meta-Analysis of European-Ancestry Cohorts.

The mu1 opioid receptor gene, OPRM1, has long been a high-priority candidate for human genetic studies of addiction. Because of its potential functional significance, the non-synonymous variant rs1799971 (A118G, Asn40Asp) in OPRM1 has been extensively studied, yet its role in addiction has remained unclear, with conflicting association findings. To resolve the question of what effect, if any, rs1799971 has on substance dependence risk, we conducted collaborative meta-analyses of 25 datasets with over 28,000 European-ancestry subjects. We investigated non-specific risk for "general" substance dependence, comparing cases dependent on any substance to controls who were non-dependent on all assessed substances. We also examined five specific substance dependence diagnoses: DSM-IV alcohol, opioid, cannabis, and cocaine dependence, and nicotine dependence defined by the proxy of heavy/light smoking (cigarettes-per-day >20 vs. ≤ 10). The G allele showed a modest protective effect on general substance dependence (OR = 0.90, 95% C.I. [0.83-0.97], p value = 0.0095, N = 16,908). We observed similar effects for each individual substance, although these were not statistically significant, likely because of reduced sample sizes. We conclude that rs1799971 contributes to mechanisms of addiction liability that are shared across different addictive substances. This project highlights the benefits of examining addictive behaviors collectively and the power of collaborative data sharing and meta-analyses.

Validation of an acoustic gastrointestinal surveillance biosensor for postoperative ileus.

BACKGROUND: Postoperative ileus (POI) can worsen outcomes, increase cost, and prolong hospitalization. An objective marker could help identify POI patients who should not be prematurely fed. We developed a disposable, non-invasive acoustic gastro-intestinal surveillance (AGIS) biosensor. We tested whether AGIS can distinguish healthy controls from patients recovering from abdominal surgery. STUDY DESIGN: AGIS is a disposable plastic device embedded with a microphone that adheres to the abdominal wall and connects to a computer that measures acoustic event rates. We compared intestinal rates of healthy subjects using AGIS for 60 min after a standardized meal to recordings of two postoperative groups: (1) patients tolerating standardized feeding and (2) POI patients. We compared intestinal rates among groups using ANOVA and t tests. RESULTS: There were 8 healthy controls, 7 patients tolerating feeding, and 25 with POI; mean intestinal rates were 0.14, 0.03, and 0.016 events per second, respectively (ANOVA p < 0.001). AGIS separated patients from controls with 100 % sensitivity and 97 % specificity. Among patients, rates were higher in fed versus POI subjects (p = 0.017). CONCLUSION: Non-invasive, abdominal acoustic monitoring distinguishes POI from non-POI subjects. Future research will test whether AGIS can identify patients at risk for development of POI and assist with postoperative feeding decisions.

Low uptake of colorectal cancer screening among African Americans in an integrated Veterans Affairs health care network.

BACKGROUND: African Americans have the highest incidence and mortality from colorectal cancer (CRC). Despite guidelines to initiate screening with colonoscopy at age 45 in African Americans, the CRC incidence remains high in this group. OBJECTIVE: To examine the rates and predictors of CRC screening uptake as well as time to screening in a population of African Americans and non-African Americans in a health care system that minimizes variations in insurance and access. DESIGN: Retrospective cohort study. SETTING: Greater Los Angeles Veterans Affairs (VA) Healthcare System. PATIENTS: Random sample (N = 357) of patients eligible for initial CRC screening. MAIN OUTCOME MEASUREMENTS: Uptake of any screening method; uptake of colonoscopy, in particular; predictors of screening; and time to screening in African Americans and non-African Americans. RESULTS: The overall screening rate by any method was 50%. Adjusted rates for any screening were lower among African Americans than non-African Americans (42% vs 58%; odds ratio [OR] 0.49; 95% confidence interval [CI], 0.31-0.77). Colonoscopic screening was also lower in African Americans (11% vs 23%; adjusted OR 0.43; 95% CI, 0.24-0.77). In addition to race, homelessness, lower service connectedness, taking more prescription drugs, and not seeing a primary care provider within 2 years of screening eligibility predicted lower uptake of screening. Time to screening colonoscopy was longer in African Americans (adjusted hazard ratio 0.43; 95% CI, 0.25-0.75). LIMITATIONS: The sample may not be generalizable. CONCLUSIONS: We found marked disparities in CRC screening despite similar access to care across races. Despite current guidelines aimed at increasing CRC screening in African Americans, participation in screening remained low, and use of colonoscopy was infrequent.