Phenotyping clonal populations of glioma stem cell reveals a high degree of plasticity in response to changes of microenvironment.

The phenotype of glioma-initiating cells (GIC) is modulated by cell-intrinsic and cell-extrinsic factors. Phenotypic heterogeneity and plasticity of GIC is an important limitation to therapeutic approaches targeting cancer stem cells. Plasticity also presents a challenge to the identification, isolation, and propagation of purified cancer stem cells. Here we use a barcode labelling approach of GIC to generate clonal populations over a number of passages, in combination with phenotyping using the established stem cell markers CD133, CD15, CD44, and A2B5. Using two cell lines derived from isocitrate dehydrogenase (IDH)-wildtype glioblastoma, we identify a remarkable heterogeneity of the phenotypes between the cell lines. During passaging, clonal expansion manifests as the emergence of a limited number of barcoded clones and a decrease in the overall number of clones. Dual-labelled GIC are capable of forming traceable clonal populations which emerge after as few as two passages from mixed cultures and through analyses of similarity of relative proportions of 16 surface markers we were able to pinpoint the fate of such populations. By generating tumour organoids we observed a remarkable persistence of dominant clones but also a significant plasticity of stemness marker expression. Our study presents an experimental approach to simultaneously barcode and phenotype glioma-initiating cells to assess their functional properties, for example to screen newly established GIC for tumour-specific therapeutic vulnerabilities.

Accounting for the Rise of Health Spending and Longevity.

We estimate a stochastic life-cycle model of endogenous health spending, asset accumulation and retirement to investigate the causes behind the increase in health spending and longevity in the U.S. over the period 1965-2005. Accounting for changes over time in taxes, transfers, Social Security, income, health insurance, smoking and obesity, and technological progress, we estimate that technological progress is responsible for half of the increase in life expectancy over the period. Substantial growth in health spending over the period is largely the result of growth in economic resources and the generosity of health insurance, with a modest role for medical technological progress. The growth in spending does not come from changes in a single source, but sources jointly interacted to increase spending: complementarity effects explain up to 26.3% of the increase in health spending. Overall, for those born in 1940, the combined changes in resources and health insurance that occurred over the period are valued at 35.7% of lifetime consumption.

The KDM5A/RBP2 histone demethylase represses NOTCH signaling to sustain neuroendocrine differentiation and promote small cell lung cancer tumorigenesis.

More than 90% of small cell lung cancers (SCLCs) harbor loss-of-function mutations in the tumor suppressor gene RB1 The canonical function of the RB1 gene product, pRB, is to repress the E2F transcription factor family, but pRB also functions to regulate cellular differentiation in part through its binding to the histone demethylase KDM5A (also known as RBP2 or JARID1A). We show that KDM5A promotes SCLC proliferation and SCLC's neuroendocrine differentiation phenotype in part by sustaining expression of the neuroendocrine transcription factor ASCL1. Mechanistically, we found that KDM5A sustains ASCL1 levels and neuroendocrine differentiation by repressing NOTCH2 and NOTCH target genes. To test the role of KDM5A in SCLC tumorigenesis in vivo, we developed a CRISPR/Cas9-based mouse model of SCLC by delivering an adenovirus (or an adeno-associated virus [AAV]) that expresses Cre recombinase and sgRNAs targeting Rb1, Tp53, and Rbl2 into the lungs of Lox-Stop-Lox Cas9 mice. Coinclusion of a KDM5A sgRNA decreased SCLC tumorigenesis and metastasis, and the SCLCs that formed despite the absence of KDM5A had higher NOTCH activity compared to KDM5A+/+ SCLCs. This work establishes a role for KDM5A in SCLC tumorigenesis and suggests that KDM5 inhibitors should be explored as treatments for SCLC.

Cells Lacking the RB1 Tumor Suppressor Gene Are Hyperdependent on Aurora B Kinase for Survival.

Small cell lung cancer (SCLC) accounts for 15% of lung cancers and is almost always linked to inactivating RB1 and TP53 mutations. SCLC frequently responds, albeit briefly, to chemotherapy. The canonical function of the RB1 gene product RB1 is to repress the E2F transcription factor family. RB1 also plays both E2F-dependent and E2F-independent mitotic roles. We performed a synthetic lethal CRISPR/Cas9 screen in an RB1 -/- SCLC cell line that conditionally expresses RB1 to identify dependencies that are caused by RB1 loss and discovered that RB1 -/- SCLC cell lines are hyperdependent on multiple proteins linked to chromosomal segregation, including Aurora B kinase. Moreover, we show that an Aurora B kinase inhibitor is efficacious in multiple preclinical SCLC models at concentrations that are well tolerated in mice. These results suggest that RB1 loss is a predictive biomarker for sensitivity to Aurora B kinase inhibitors in SCLC and perhaps other RB1 -/- cancers. SIGNIFICANCE: SCLC is rarely associated with actionable protooncogene mutations. We did a CRISPR/Cas9-based screen that showed that RB1 -/- SCLC are hyperdependent on AURKB, likely because both genes control mitotic fidelity, and confirmed that Aurora B kinase inhibitors are efficacious against RB1 -/- SCLC tumors in mice at nontoxic doses.See related commentary by Dick and Li, p. 169.This article is highlighted in the In This Issue feature, p. 151.

Dental anomalies in panoramic radiographs of pediatric patients.

A panoramic radiograph is more likely utilized in children with high caries risk and mixed dentition, and it can be complemented by other X-rays (such as periapical and/or bitewings). This study analyzed 1359 panoramic radiographs taken over 33 years at the Pedodontics Clinic of the State University of Rio de Janeiro in order to determine the prevalence of dental anomalies in mixed dentition children. The population evaluated had 670 (49.3%) boys and 689 (50.7%) girls, ranging in age from 5-12 years, with a median age of 8 years. The total prevalence of anomalies detected was 11.72%; anodontia and supernumerary teeth were the most reported (4.63% and 3.31%, respectively). Statistical differences noted were in the presence of supernumary teeth in males (4.9%, P <.001) and the presence of anodontia in females (6.1%, P = .009). Based on these findings, a panoramic radiograph can help to analyze transitional dentition, as well as complement the clinical examination at the first dental visit of a pediatric patient with a high risk for caries.

Profilaxia antibiótica de infecção pós-operatória nos períodos pré e pós-operatórios em cirurgia de terceiros molares / Antibiotic prophylaxis of postoperative infection on pre and postoperative periods in third molars surgery

O uso rotineiro de profilaxia antibiótica em cirurgia para exodontia de terceiros molares é controverso. O objetivo deste trabalho foi analisar a conduta farmacológica de cirurgiões-dentistas que realizam este tipo de extração dentária em relação à profilaxia de infecções pós-operatórias, comparando os dados à conduta dos professores das disciplinas de Cirurgia Bucomaxilofacialdo curso de Odontologia da Universidade Luterana do Brasil, Canoas/RS. Para tanto, foi aplicado um questionário a 60 profissionais com o intuito de verificar os critérios de indicação de profilaxia antibiótica parainfecções pós-operatórias, posologia farmacológica e associação com controle químico do biofilme bacteriano,relacionando essas variáveis ao curso de origem e tempo de formado do profissional. Conclui-se que a maioria dos entrevistados indica profilaxia para infecções pós-operatórias, entretanto não segue um protocolo definido sustentado em evidências científicas

Alterações cerebrais em recém-nascidos pré-termos detectadas por ultra-sonografia e associação com procedimentos de reanimação na sala de parto / Association of ultrasonogtaphic cerebral alterations in preterm infants and resuscitation procedures

Objetivo: avaliar no prematuro a prevalência de hemorragia intraventricular (HIV) e leucomalácia periventricular (LPV) e sua associação aos procedeimentos de reanimação em sala de parto. Métodos: estudo prospectivo, tipo coorte, em crianças nascidas com peso igual ou menor que 1.500 g no Hospital das Clínicas da UFMG, no período de outubro de 2000 a fevereiro de 2002. Os exames ultra-sonográficos foram realizados pelo autor e os dados perinatais obtidos do prontuário do serviço. Resultados: dos 104 pacientes estudados, 14 (13,5 por cento) apresentaram HIV e 9 (8,7 por cento), LPV. Na análise multivariada por regressão logística, as variáveis que se associaram significativamente à HIV foram: uso de corticosteróide no pré-natal, dias de ventilação mecânica, tempo de bolsa rota e necessidade de ventilação compressão positiva na sala de parto. Associaram-se à LPV o peso de nascimento e a necessiddade de intubação na sala de parto. Conclusões: as alterações neurológicas derectáveis pela ultra-sonografia transfontanelar, principalmente as hemorragias perintraventriculares e a leucomalácia periventricular, têm alta prevalência entre os prematuros. A necessidade de ventilação co pressão positiva na sala de parto e a intubação associaram-se significativamente à HIV e à LPV.