RESUMO
Posterior fossa group A (PFA) ependymoma is a lethal brain cancer diagnosed in infants and young children. The lack of driver events in the PFA linear genome led us to search its 3D genome for characteristic features. Here, we reconstructed 3D genomes from diverse childhood tumor types and uncovered a global topology in PFA that is highly reminiscent of stem and progenitor cells in a variety of human tissues. A remarkable feature exclusively present in PFA are type B ultra long-range interactions in PFAs (TULIPs), regions separated by great distances along the linear genome that interact with each other in the 3D nuclear space with surprising strength. TULIPs occur in all PFA samples and recur at predictable genomic coordinates, and their formation is induced by expression of EZHIP. The universality of TULIPs across PFA samples suggests a conservation of molecular principles that could be exploited therapeutically.
RESUMO
Achieving the long-term stability of perovskite solar cells is arguably the most important challenge required to enable widespread commercialization. Understanding the perovskite crystallization process and its direct impact on device stability is critical to achieving this goal. The commonly employed dimethyl-formamide/dimethyl-sulfoxide solvent preparation method results in a poor crystal quality and microstructure of the polycrystalline perovskite films. In this work, we introduce a high-temperature dimethyl-sulfoxide-free processing method that utilizes dimethylammonium chloride as an additive to control the perovskite intermediate precursor phases. By controlling the crystallization sequence, we tune the grain size, texturing, orientation (corner-up versus face-up) and crystallinity of the formamidinium (FA)/caesium (FA)yCs1-yPb(IxBr1-x)3 perovskite system. A population of encapsulated devices showed improved operational stability, with a median T80 lifetime (the time over which the device power conversion efficiency decreases to 80% of its initial value) for the steady-state power conversion efficiency of 1,190 hours, and a champion device showed a T80 of 1,410 hours, under simulated sunlight at 65 °C in air, under open-circuit conditions. This work highlights the importance of material quality in achieving the long-term operational stability of perovskite optoelectronic devices.
Assuntos
Amidinas , Luz Solar , Cátions , Dimetil SulfóxidoRESUMO
BACKGROUND: Hip offset, version, and length are interdependent femoral variables which determine stability and leg length. Balancing these competing variables remains a core challenge in hip arthroplasty. The potential benefits of modular femoral stems have been overshadowed by higher rates of failure. The objective of this study was to assess the survivorship of a unique dual-modular femoral stem at an average 15-year follow-up period. METHODS: The records of all patients with osteoarthritis who underwent primary total hip arthroplasty with this device between 2004-2009 were reviewed. There were no exclusions for BMI or other factors. We examined the data with Kaplan-Meier survival analysis. The primary endpoint for survival was mechanical failure of the modular neck-body junction. RESULTS: The survivorship of this device in 172 subjects was 100% with none experiencing mechanical failure of the modular junction at an average of 15 years. 60 patients died of causes unrelated to their THA and 9 patients were lost to follow-up. There were three early (≤ 12 months) dislocations (1.7%), and seven total dislocations (4.1%). 16 patients underwent reoperations during the follow-up period, none for any complication of the modular junction. Radiographic results showed well-fixed femoral stems in all cases. There were no leg length discrepancies of greater than 10 mm, and 85% were within 5 mm. CONCLUSION: There were no mechanical failures of the modular junction in any of the subjects over the average 15-year period, demonstrating that this dual-modular design is not associated with increased failure rates. We achieved a 1.7% early dislocation rate and a 4.1% total dislocation rate without any clinically significant leg length discrepancies.
Assuntos
Artroplastia de Quadril , Prótese de Quadril , Desenho de Prótese , Falha de Prótese , Humanos , Artroplastia de Quadril/instrumentação , Artroplastia de Quadril/efeitos adversos , Artroplastia de Quadril/métodos , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Adulto , Seguimentos , Osteoartrite do Quadril/cirurgia , Estudos Retrospectivos , Idoso de 80 Anos ou mais , Estimativa de Kaplan-Meier , Reoperação/estatística & dados numéricos , Fêmur/cirurgia , Fêmur/diagnóstico por imagem , Fatores de TempoRESUMO
BACKGROUND: Clinical teaching during encounters with real patients lies at the heart of medical education. Mixed reality (MR) using a Microsoft HoloLens 2 (HL2) offers the potential to address several challenges: including enabling remote learning; decreasing infection control risks; facilitating greater access to medical specialties; and enhancing learning by vertical integration of basic principles to clinical application. We aimed to assess the feasibility and usability of MR using the HL2 for teaching in a busy, tertiary referral university hospital. METHODS: This prospective observational study examined the use of the HL2 to facilitate a live two-way broadcast of a clinician-patient encounter, to remotely situated third and fourth year medical students. System Usability Scale (SUS) Scores were elicited from participating medical students, clinician, and technician. Feedback was also elicited from participating patients. A modified Evaluation of Technology-Enhanced Learning Materials: Learner Perceptions Questionnaire (mETELM) was completed by medical students and patients. RESULTS: This was a mixed methods prospective, observational study, undertaken in the Day of Surgery Assessment Unit. Forty-seven medical students participated. The mean SUS score for medical students was 71.4 (SD 15.4), clinician (SUS = 75) and technician (SUS = 70) indicating good usability. The mETELM Questionnaire using a 7-point Likert Scale demonstrated MR was perceived to be more beneficial than a PowerPoint presentation (Median = 7, Range 6-7). Opinion amongst the student cohort was divided as to whether the MR tutorial was as beneficial for learning as a live patient encounter would have been (Median = 5, Range 3-6). Students were positive about the prospect of incorporating of MR in future tutorials (Median = 7, Range 5-7). The patients' mETELM results indicate the HL2 did not affect communication with the clinician (Median = 7, Range 7-7). The MR tutorial was preferred to a format based on small group teaching at the bedside (Median = 6, Range 4-7). CONCLUSIONS: Our study findings indicate that MR teaching using the HL2 demonstrates good usability characteristics for providing education to medical students at least in a clinical setting and under conditions similar to those of our study. Also, it is feasible to deliver to remotely located students, although certain practical constraints apply including Wi-Fi and audio quality.
Assuntos
Estudos de Viabilidade , Estudantes de Medicina , Humanos , Estudos Prospectivos , Estudantes de Medicina/psicologia , Feminino , Masculino , Autorrelato , Educação de Graduação em Medicina/métodos , Adulto , Adulto Jovem , Realidade Aumentada , Educação a Distância , Inquéritos e QuestionáriosRESUMO
Formamidinium lead triiodide (FAPbI3) is the leading candidate for single-junction metal-halide perovskite photovoltaics, despite the metastability of this phase. To enhance its ambient-phase stability and produce world-record photovoltaic efficiencies, methylenediammonium dichloride (MDACl2) has been used as an additive in FAPbI3. MDA2+ has been reported as incorporated into the perovskite lattice alongside Cl-. However, the precise function and role of MDA2+ remain uncertain. Here, we grow FAPbI3 single crystals from a solution containing MDACl2 (FAPbI3-M). We demonstrate that FAPbI3-M crystals are stable against transformation to the photoinactive δ-phase for more than one year under ambient conditions. Critically, we reveal that MDA2+ is not the direct cause of the enhanced material stability. Instead, MDA2+ degrades rapidly to produce ammonium and methaniminium, which subsequently oligomerizes to yield hexamethylenetetramine (HMTA). FAPbI3 crystals grown from a solution containing HMTA (FAPbI3-H) replicate the enhanced α-phase stability of FAPbI3-M. However, we further determine that HMTA is unstable in the perovskite precursor solution, where reaction with FA+ is possible, leading instead to the formation of tetrahydrotriazinium (THTZ-H+). By a combination of liquid- and solid-state NMR techniques, we show that THTZ-H+ is selectively incorporated into the bulk of both FAPbI3-M and FAPbI3-H at â¼0.5 mol % and infer that this addition is responsible for the improved α-phase stability.
RESUMO
BACKGROUND: Technetium-99 (99m Tc) lymphoscintigraphy with blue dye injection is an accepted method for sentinel lymph node (SLN) mapping, but blue dye has known adverse effects, and injection of 99m Tc may increase time under anesthesia for pediatric patients. Indocyanine green (ICG) may serve as an adjunct to assist with visibility and identification of SLNs. We hypothesized that sensitivity of ICG was similar to blue dye in SLN biopsies. METHODS: Thirty patients (36 procedures with 96 total specimens) underwent preoperative intradermal injection of 99m Tc, followed by intradermal injection of isosulfan blue and ICG. Test characteristics of blue dye, ICG, and 99m Tc included sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: ICG had a sensitivity of 87% and PPV of 83% for detection of 99m Tc-hot lymph nodes; blue dye had a sensitivity of 44% and PPV of 97%. For detection of pathologically confirmed lymph nodes, ICG had a sensitivity of 84% and a positive predictive value (PPV) of 91%. 99m Tc had a sensitivity of 82% and a PPV of 94%. ICG had no significant difference in odds of being positive in pathology-confirmed lymph nodes compared to 99m Tc (odds ratio [OR], 0.818; 95% confidence interval [CI], 0.3-2.172; p = .823) and had higher odds than isosulfan blue (OR, 0.025, 95% CI, 0.001-0.148; p < .001). CONCLUSION: This study established the efficacy of ICG as an adjunct to SLNB in the pediatric and young adult population. ICG was safe, more efficacious than blue dye, and may obviate the need for lymphoscintigraphy in selected patients resulting in reduced time under anesthesia.
Assuntos
Verde de Indocianina , Linfonodo Sentinela , Humanos , Adulto Jovem , Criança , Linfonodo Sentinela/diagnóstico por imagem , Linfonodo Sentinela/cirurgia , Linfonodo Sentinela/patologia , Compostos Radiofarmacêuticos , Corantes , Biópsia de Linfonodo Sentinela/métodos , Linfonodos/diagnóstico por imagem , Linfonodos/cirurgia , Linfonodos/patologiaRESUMO
BACKGROUND: In 2014, infliximab (IFX) was listed on the Australian Pharmaceutical Benefits Scheme for acute severe ulcerative colitis (ASUC) and is now the preferred option for medical salvage, superseding cyclosporin A (CsA). Optimal dosing schedules for IFX remain unknown. AIM: The authors aim to evaluate the effect of changing from predominantly CsA to almost exclusively IFX for the treatment of steroid-refractory ASUC on colectomy rates. METHODS: A retrospective review was performed of patients admitted with ASUC between 2012 and 2020. Patients were categorised into two groups according to year of presentation - either 'historical treatment' cohort (2012-2014), when CsA was primarily used, or 'contemporary treatment' cohort (2014-2020), when IFX was mostly prescribed, in either standard or intensive doses. RESULTS: One hundred thirty-nine patients were included; 37 in the historical treatment cohort and 102 in the contemporary treatment cohort. In the historical treatment cohort, 12 of 37 received salvage therapy and eight (67%) received CsA. In the contemporary treatment cohort, 49 of 102 patients received salvage therapy, 40 (82%) with IFX, of whom 22 (53%) received intensified doses. Colectomy rates were similar at 30 days, 6 months and 12 months between historical and contemporary treatment cohorts (14% vs 12% [P = 0.77], 19% vs 18% [P > 0.99],and 22% vs 18% [P = 0.63], respectively). Difference in 12-month colectomy rates between standard versus intensive IFX did not meet statistical significance (three of 21 [14%] vs nine of 22 [41%]. respectively; P = 0.09). CONCLUSION: There was no difference in 30-day, 6-month or 12-month colectomy rates between the historical treatment and contemporary treatment cohorts. The use of IFX, rather than CsA, even at intensified dosing, does not appear to reduce the colectomy rate observed in our patients.
Assuntos
Colite Ulcerativa , Humanos , Colite Ulcerativa/tratamento farmacológico , Colite Ulcerativa/cirurgia , Austrália , Infliximab/uso terapêutico , Ciclosporina/uso terapêutico , Estudos Retrospectivos , Colectomia , Resultado do TratamentoRESUMO
Wilms tumor (WT) is the most common renal malignancy in children. Children with favorable histology WT achieve survival rates of over 90%. Twelve percent of patients present with metastatic disease, most commonly to the lungs. The presence of a pleural effusion at the time of diagnosis of WT may be noted on staging imaging; however, minimal data exist regarding the significance and prognostic importance of this finding. The objectives of our study are to identify the incidence of pleural effusions in patients with WT, and to determine the potential impact on oncologic outcomes. A multi-institutional retrospective review was performed from January 2009 to December 2019, including children with WT and a pleural effusion on diagnostic imaging treated at Pediatric Surgical Oncology Research Collaborative (PSORC) participating institutions. Of 1259 children with a new WT diagnosis, 94 (7.5%) had a pleural effusion. Patients with a pleural effusion were older than those without (median 4.3 vs 3.5 years; P = .004), and advanced stages were more common (local stage III 85.9% vs 51.9%; P < .0001). Only 14 patients underwent a thoracentesis for fluid evaluation; 3 had cytopathologic evidence of malignant cells. Event-free and overall survival of all children with WT and pleural effusions was 86.2% and 91.5%, respectively. The rate and significance of malignant cells present in pleural fluid is unknown due to low incidence of cytopathologic analysis in our cohort; therefore, the presence of an effusion does not appear to necessitate a change in therapy. Excellent survival can be expected with current stage-specific treatment regimens.
Assuntos
Neoplasias Renais , Derrame Pleural Maligno , Derrame Pleural , Oncologia Cirúrgica , Tumor de Wilms , Criança , Humanos , Incidência , Neoplasias Renais/epidemiologia , Neoplasias Renais/cirurgia , Derrame Pleural/epidemiologia , Derrame Pleural/etiologia , Derrame Pleural Maligno/epidemiologia , Derrame Pleural Maligno/etiologia , Derrame Pleural Maligno/cirurgia , Estudos Retrospectivos , Tumor de Wilms/epidemiologia , Tumor de Wilms/cirurgiaRESUMO
We investigated the role of 3D genome architecture in instructing functional properties of glioblastoma stem cells (GSCs) by generating sub-5-kb resolution 3D genome maps by in situ Hi-C. Contact maps at sub-5-kb resolution allow identification of individual DNA loops, domain organization, and large-scale genome compartmentalization. We observed differences in looping architectures among GSCs from different patients, suggesting that 3D genome architecture is a further layer of inter-patient heterogeneity for glioblastoma. Integration of DNA contact maps with chromatin and transcriptional profiles identified specific mechanisms of gene regulation, including the convergence of multiple super enhancers to individual stemness genes within individual cells. We show that the number of loops contacting a gene correlates with elevated transcription. These results indicate that stemness genes are hubs of interaction between multiple regulatory regions, likely to ensure their sustained expression. Regions of open chromatin common among the GSCs tested were poised for expression of immune-related genes, including CD276 We demonstrate that this gene is co-expressed with stemness genes in GSCs and that CD276 can be targeted with an antibody-drug conjugate to eliminate self-renewing cells. Our results demonstrate that integrated structural genomics data sets can be employed to rationally identify therapeutic vulnerabilities in self-renewing cells.
Assuntos
Neoplasias Encefálicas/genética , Cromatina/ultraestrutura , Mapeamento Cromossômico/métodos , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Proteínas de Neoplasias/genética , Antígenos B7/antagonistas & inibidores , Antígenos B7/genética , Antígenos B7/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Proliferação de Células , Cromatina/química , Elementos Facilitadores Genéticos , Perfilação da Expressão Gênica , Heterogeneidade Genética , Genoma Humano , Genômica/métodos , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Terapia de Alvo Molecular , Proteínas de Neoplasias/classificação , Proteínas de Neoplasias/metabolismo , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Cultura Primária de Células , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transcrição GênicaRESUMO
BACKGROUND AND AIMS: Hepatoblastoma (HBL) is a devastating pediatric liver cancer with multiple treatment options, but it ultimately requires surgery for a cure. The most malicious form of HBL is a chemo-resistant aggressive tumor that is characterized by rapid growth, metastases, and poor response to treatment. Very little is known of the mechanisms of aggressive HBL, and recent focuses have been on developing alternative treatment strategies. In this study, we examined the role of human chromosomal regions, called aggressive liver cancer domains (ALCDs), in liver cancer and evaluated the mechanisms that activate ALCDs in aggressive HBL. RESULTS: We found that ALCDs are critical regions of the human genome that are located on all human chromosomes, preferentially in intronic regions of the oncogenes and other cancer-associated genes. In aggressive HBL and in patients with Hepatocellular (HCC), JNK1/2 phosphorylates p53 at Ser6, which leads to the ph-S6-p53 interacting with and delivering the poly(adenosine diphosphate ribose) polymerase 1 (PARP1)/Ku70 complexes on the oncogenes containing ALCDs. The ph-S6-p53-PARP1 complexes open chromatin around ALCDs and activate multiple oncogenic pathways. We found that the inhibition of PARP1 in patient-derived xenografts (PDXs) from aggressive HBL by the Food and Drug Administration (FDA)-approved inhibitor olaparib (Ola) significantly inhibits tumor growth. Additionally, this is associated with the reduction of the ph-S6-p53/PARP1 complexes and subsequent inhibition of ALCD-dependent oncogenes. Studies in cultured cancer cells confirmed that the Ola-mediated inhibition of the ph-S6-p53-PARP1-ALCD axis inhibits proliferation of cancer cells. CONCLUSIONS: In this study, we showed that aggressive HBL is moderated by ALCDs, which are activated by the ph-S6-p53/PARP1 pathway. By using the PARP1 inhibitor Ola, we suppressed tumor growth in HBL-PDX models, which demonstrated its utility in future clinical models.
Assuntos
Proliferação de Células/efeitos dos fármacos , Hepatoblastoma , Neoplasias Hepáticas , Ftalazinas/farmacologia , Piperazinas/farmacologia , Poli(ADP-Ribose) Polimerase-1/metabolismo , Animais , Células Cultivadas , Hepatoblastoma/tratamento farmacológico , Hepatoblastoma/metabolismo , Humanos , Autoantígeno Ku/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Camundongos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Proteínas Quinases S6 Ribossômicas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Juvenile Pilocytic Astrocytomas (JPAs) are one of the most common pediatric brain tumors, and they are driven by aberrant activation of the mitogen-activated protein kinase (MAPK) signaling pathway. RAF-fusions are the most common genetic alterations identified in JPAs, with the prototypical KIAA1549-BRAF fusion leading to loss of BRAF's auto-inhibitory domain and subsequent constitutive kinase activation. JPAs are highly vascular and show pervasive immune infiltration, which can lead to low tumor cell purity in clinical samples. This can result in gene fusions that are difficult to detect with conventional omics approaches including RNA-Seq. METHODS: To this effect, we applied RNA-Seq as well as linked-read whole-genome sequencing and in situ Hi-C as new approaches to detect and characterize low-frequency gene fusions at the genomic, transcriptomic and spatial level. RESULTS: Integration of these datasets allowed the identification and detailed characterization of two novel BRAF fusion partners, PTPRZ1 and TOP2B, in addition to the canonical fusion with partner KIAA1549. Additionally, our Hi-C datasets enabled investigations of 3D genome architecture in JPAs which showed a high level of correlation in 3D compartment annotations between JPAs compared to other pediatric tumors, and high similarity to normal adult astrocytes. We detected interactions between BRAF and its fusion partners exclusively in tumor samples containing BRAF fusions. CONCLUSIONS: We demonstrate the power of integrating multi-omic datasets to identify low frequency fusions and characterize the JPA genome at high resolution. We suggest that linked-reads and Hi-C could be used in clinic for the detection and characterization of JPAs.
Assuntos
Astrocitoma , Neoplasias Encefálicas , Criança , Adulto , Humanos , Multiômica , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas de Fusão Oncogênica/genética , Astrocitoma/patologia , Neoplasias Encefálicas/patologia , Proteínas Tirosina Fosfatases Classe 5 Semelhantes a ReceptoresRESUMO
PURPOSE: To provide plan backup resiliency for patients treated on a solitary high definition multileaf collimator (HDMLC) linac by developing a fully integrated Eclipse script, which converts patient plans initially optimized on Millennium-120 (M120) MLC to dosimetrically equivalent leaf motions for delivery on HDMLC. In the event of HDMLC machine downtime, affected patients can be transferred to Millennium-120 units, and their backup plan delivered without delay. METHODS: Write-enabled Eclipse scripting is leveraged to generate HDMLC treatment fields with control points parameterized to mimic apertures of an existing Millennium-120 VMAT plan. Non-parity between intermediate control point gantry angles of script generated arcs relative to VMAT is reconciled through an interpolation subroutine to correct for the apertures and monitor units that would have existed at intermediate angles. Differences in dosimetric leaf gap are corrected by displacing the subset of leaves undergoing dynamic motion. A nominal change to plan normalization corrects for remaining discrepancies between beam models. RESULTS: Over 220 non-SABR VMAT patients were treated on a solitary HDMLC linac with plans converted using the developed script. All have undergone streamlined RO review and physics quality assurance (QA), where the converted plan replicates the original leaf patterns, representing a minor dosimetric perturbation. Analyzing a subset of converted plans delivered at four anatomical sites, on average 99.3% of points pass the 1%/1 mm gamma criterion. Dose-volume histograms between the original and converted plans are in excellent agreement. ArcCheck measurements comparing delivery of the converted HDMLC plan to the calculated M120 dose distribution averaged a gamma pass rate of 99.4% (95.2%) at a 3%/3 mm (2%/2 mm) criterion. The conversion process takes 30 s to run, avoids errors in exporting/re-importing, and generates leaf motions deliverable within machine limits. CONCLUSION: The methodology developed for automated plan conversion helped maximize the utilization of a solitary HDMLC linac, while preserving backup interoperability with minimal overhead.
Assuntos
Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Humanos , Aceleradores de Partículas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , SoftwareRESUMO
PURPOSE: Previous studies have suggested axillary lymph node dissection (ALND) can be omitted in early breast cancer patients undergoing mastectomy with positive lymph nodes (LNs). We assessed the national utilization of ALND and overall survival (OS) for larger, locally advanced tumors in patients undergoing mastectomy with positive LNs. METHODS: The National Cancer Database from 2006 to 2016 was queried for mastectomy patients with clinical T3/T4, N0 tumors, and 1-2 positive LNs. Trends and outcomes for ALND were compared to sentinel lymph node biopsy (SLNB) alone. RESULTS: Thousand nine hundred and seventeen women were included. The proportion of ALND decreased from 70% pre-Z0011 to 52% post-Z0011. On Kaplan-Meier analysis, ALND had better OS compared to SLNB alone (p < 0.01). On multivariate analysis, age (p < 0.01), chemotherapy (p < 0.01), and hormonal therapy (p < 0.01) were associated with better OS. In patients who received adjuvant radiation therapy (ART) ALND improved OS on multivariate analysis (p < 0.01). CONCLUSION: This is the first large database study to demonstrate a national trend to forego ALND in mastectomy patients with large or locally advanced tumors (T3/T4abc) and 1-2 positive lymph nodes. This study suggests a survival benefit for ALND, particularly in patients receiving ART. Careful consideration and further investigations should be performed prior to omitting ALND this patient population.
Assuntos
Neoplasias da Mama , Linfonodo Sentinela , Axila , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Excisão de Linfonodo , Linfonodos/cirurgia , Mastectomia , Biópsia de Linfonodo SentinelaRESUMO
Understanding the electronic energy landscape in metal halide perovskites is essential for further improvements in their promising performance in thin-film photovoltaics. Here, we uncover the presence of above-bandgap oscillatory features in the absorption spectra of formamidinium lead triiodide thin films. We attribute these discrete features to intrinsically occurring quantum confinement effects, for which the related energies change with temperature according to the inverse square of the intrinsic lattice parameter, and with peak index in a quadratic manner. By determining the threshold film thickness at which the amplitude of the peaks is appreciably decreased, and through ab initio simulations of the absorption features, we estimate the length scale of confinement to be 10-20 nm. Such absorption peaks present a new and intriguing quantum electronic phenomenon in a nominally bulk semiconductor, offering intrinsic nanoscale optoelectronic properties without necessitating cumbersome additional processing steps.
RESUMO
PURPOSE OF REVIEW: To summarize recent evidence demonstrating increased cardiovascular disease (CVD) risk, and how CVD risk may be reduced, in patients with nonalcoholic fatty liver disease (NAFLD). RECENT FINDINGS: NAFLD is a multisystem disease, defined by a spectrum of liver fat-associated conditions extending from simple steatosis, to inflammation, fibrosis and cirrhosis. NAFLD not only increases the risk of liver morbidity and mortality but also increases the risk of CVD morbidity and mortality and is associated with recognized CVD risk factors such as hypertension, atherogenic dyslipidaemia, type 2 diabetes mellitus and chronic kidney disease. Evidence suggests that the liver fibrosis stage may be a strong CVD risk factor. Lifestyle measures (e.g. weight loss and increased physical activity) are effective in improving CVD risk factors. Hypoglycaemic agents, such as the peroxisome proliferator-activated receptor gamma agonist pioglitazone and the glucagon-like peptide-1 receptor agonist liraglutide, reduce cardiovascular risk and may improve liver histology. Statin and antihypertensive treatments are well tolerated and currently it is unclear whether novel antifibrotic drugs will reduce CVD risk. SUMMARY: Assessment and treatment of increased cardiovascular risk is important in patients with NAFLD. If not contra-indicated, pioglitazone or a glucagon-like peptide 1 agonist should be considered and may benefit both CVD risk and early liver disease.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Hepatopatia Gordurosa não Alcoólica , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/prevenção & controle , Fatores de Risco de Doenças Cardíacas , Humanos , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Fatores de RiscoRESUMO
BACKGROUND: Hypothermic circulatory arrest (HCA) is a technique used for complex repair of the aorta, but it can be associated with neurologic morbidity. To better understand the molecular changes that underlie ischemic brain injury, we assessed gene expression and cytokine/chemokine polypeptide concentration in brain tissue and cerebrospinal fluid (CSF) of canines that underwent two hours of HCA. MATERIALS AND METHODS: Adult male canines were cannulated peripherally for cardiopulmonary bypass, cooled to 18°C, and arrested for two hours. Animals were euthanized two, eight, or 24 hours post-HCA (n = 8 per group), and their brains were compared to brains from eight normal canines, using gene expression microarray analysis, cytokine assay, and histopathology. RESULTS: Two to eight hours after HCA, pro-inflammatory cytokine mRNAs increased markedly, and gene expression was enriched within signaling pathways related to neuroinflammation or ischemic injury. Concentrations of pro-inflammatory cytokine polypeptides IL-6, IL-8, IL-1ß, and CCL2 were very low in normal canine brain, whereas anti-inflammatory IL-10 and TGF-ß1 were expressed at moderate levels. Pro-inflammatory cytokine concentrations rose robustly in cerebral tissue and CSF after HCA. IL-6 and IL-8 peaked at eight hours and declined at 24 hours, while IL-1ß and CCL2 remained elevated. Concentrations of anti-inflammatory IL-10 and TGF-ß1 were maintained after HCA, with a significant increase in TGF-ß1 at 24 hours. CONCLUSIONS: These cytokines represent potential diagnostic markers for ischemic neurologic injury that could be used to assess neurologic injury in patients undergoing HCA. The cellular mechanisms underlying this pro-inflammatory, ischemic-induced injury represent potential targets for neuroprotection in the future.
Assuntos
Isquemia Encefálica/imunologia , Parada Circulatória Induzida por Hipotermia Profunda/efeitos adversos , Citocinas/metabolismo , Mediadores da Inflamação/metabolismo , Animais , Biomarcadores/líquido cefalorraquidiano , Biomarcadores/metabolismo , Encéfalo/irrigação sanguínea , Encéfalo/imunologia , Encéfalo/patologia , Isquemia Encefálica/líquido cefalorraquidiano , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/patologia , Citocinas/líquido cefalorraquidiano , Modelos Animais de Doenças , Cães , Perfilação da Expressão Gênica , Humanos , Mediadores da Inflamação/líquido cefalorraquidiano , MasculinoRESUMO
BACKGROUND: Hypothermic circulatory arrest (HCA) is associated with neurologic morbidity, in part mediated by activation of the N-methyl-D-aspartate glutamate receptor causing excitotoxicity and neuronal apoptosis. Using a canine model, we hypothesized that the N-methyl-D-aspartate receptor antagonist MK801 would provide neuroprotection and that MK801 conjugation to dendrimer nanoparticles would improve efficacy. MATERIALS AND METHODS: Male hound dogs were placed on cardiopulmonary bypass, cooled to 18°C, and underwent 90 min of HCA. Dendrimer conjugates (d-MK801) were prepared by covalently linking dendrimer surface OH groups to MK801. Six experimental groups received either saline (control), medium- (0.15 mg/kg) or high-dose (1.56 mg/kg) MK801, or low- (0.05 mg/kg), medium-, or high-dose d-MK801. At 24, 48, and 72 h after HCA, animals were scored by a standardized neurobehavioral paradigm (higher scores indicate increasing deficits). Cerebrospinal fluid was obtained at baseline, eight, 24, 48, and 72 h after HCA. At 72 h, brains were examined for histopathologic injury in a blinded manner (higher scores indicate more injury). RESULTS: Neurobehavioral deficit scores were reduced by low-dose d-MK801 on postoperative day two (P < 0.05) and by medium-dose d-MK801 on postoperative day 3 (P = 0.05) compared with saline controls, but free drug had no effect. In contrast, high-dose free MK801 significantly improved histopathology scores compared with saline (P < 0.05) and altered biomarkers of injury in cerebrospinal fluid, with a significant reduction in phosphorylated neurofilament-H for high-dose MK801 versus saline (P < 0.05). CONCLUSIONS: Treatment with MK-801 demonstrated significant improvement in neurobehavioral and histopathology scores after HCA, although not consistently across doses and conjugates.
Assuntos
Parada Circulatória Induzida por Hipotermia Profunda/efeitos adversos , Maleato de Dizocilpina/farmacologia , Fármacos Neuroprotetores/farmacologia , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Animais , Encéfalo/patologia , Cognição , Cães , MasculinoRESUMO
BACKGROUND: Pure Leydig cell tumors (LCTs) represent 0.1% of ovarian masses. Postmenopausal patients typically present with virilization. Although LCTs can be challenging to locate on conventional imaging, positron emission tomography (PET) has been demonstrated to be effective. CASE: A 64-year-old postmenopausal woman presented with alopecia, facial hirsutism, and clitoromegaly. Laboratory findings included elevated testosterone and androstenedione. Ultrasound, computed tomography, and magnetic resonance imaging showed no adnexal masses. PET did not demonstrate ovarian fludeoxyglucose-avidity. Histopathology after bilateral salpingo-oophorectomy revealed bilateral Leydig cell tumors. Her testosterone normalized 2 weeks postoperatively. CONCLUSION: We describe the occult, symptomatic, bilateral ovarian Leydig cell tumors, an occurrence that has not been described in the literature. Virilizing tumors must be considered in patients with evidence of hyperandrogenism, even without pelvic masses on imaging.
Assuntos
Tumor de Células de Leydig/patologia , Neoplasias Primárias Múltiplas/patologia , Neoplasias Ovarianas/patologia , Virilismo/diagnóstico , Androstenodiona/metabolismo , Feminino , Humanos , Tumor de Células de Leydig/complicações , Tumor de Células de Leydig/diagnóstico , Tumor de Células de Leydig/cirurgia , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Neoplasias Primárias Múltiplas/complicações , Neoplasias Primárias Múltiplas/diagnóstico , Neoplasias Primárias Múltiplas/cirurgia , Neoplasias Ovarianas/complicações , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/cirurgia , Tomografia por Emissão de Pósitrons , Pós-Menopausa , Salpingo-Ooforectomia , Testosterona/metabolismo , Virilismo/etiologia , Virilismo/metabolismoRESUMO
Hepatoblastomas exhibit the lowest mutational burden among pediatric tumors. We previously showed that epigenetic disruption is crucial for hepatoblastoma carcinogenesis. Our data revealed hypermethylation of nicotinamide N-methyltransferase, a highly expressed gene in adipocytes and hepatocytes. The expression pattern and the role of nicotinamide N-methyltransferase in pediatric liver tumors have not yet been explored, and this study aimed to evaluate the effect of nicotinamide N-methyltransferase hypermethylation in hepatoblastomas. We evaluated 45 hepatoblastomas and 26 non-tumoral liver samples. We examined in hepatoblastomas if the observed nicotinamide N-methyltransferase promoter hypermethylation could lead to dysregulation of expression by measuring mRNA and protein levels by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blot assays. The potential impact of nicotinamide N-methyltransferase changes was evaluated on the metabolic profile by high-resolution magic angle spinning nuclear magnetic resonance spectroscopy. Significant nicotinamide N-methyltransferase downregulation was revealed in hepatoblastomas, with two orders of magnitude lower nicotinamide N-methyltransferase expression in tumor samples and hepatoblastoma cell lines than in hepatocellular carcinoma cell lines. A specific TSS1500 CpG site (cg02094283) of nicotinamide N-methyltransferase was hypermethylated in tumors, with an inverse correlation between its methylation level and nicotinamide N-methyltransferase expression. A marked global reduction of the nicotinamide N-methyltransferase protein was validated in tumors, with strong correlation between gene and protein expression. Of note, higher nicotinamide N-methyltransferase expression was statistically associated with late hepatoblastoma diagnosis, a known clinical variable of worse prognosis. In addition, untargeted metabolomics analysis detected aberrant lipid metabolism in hepatoblastomas. Data presented here showed the first evidence that nicotinamide N-methyltransferase reduction occurs in hepatoblastomas, providing further support that the nicotinamide N-methyltransferase downregulation is a wide phenomenon in liver cancer. Furthermore, this study unraveled the role of DNA methylation in the regulation of nicotinamide N-methyltransferase expression in hepatoblastomas, in addition to evaluate the potential effect of nicotinamide N-methyltransferase reduction in the metabolism of these tumors. These preliminary findings also suggested that nicotinamide N-methyltransferase level may be a potential prognostic biomarker for hepatoblastoma.
Assuntos
Metilação de DNA , Regulação para Baixo , Hepatoblastoma/genética , Neoplasias Hepáticas/genética , Nicotinamida N-Metiltransferase/genética , Regiões Promotoras Genéticas/genética , Adolescente , Linhagem Celular Tumoral , Criança , Pré-Escolar , Feminino , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Hepatoblastoma/metabolismo , Hepatoblastoma/patologia , Humanos , Lactente , Recém-Nascido , Estimativa de Kaplan-Meier , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Metabolômica/métodos , Nicotinamida N-Metiltransferase/metabolismoRESUMO
BACKGROUND & AIMS: In a general population without known liver disease, we tested whether: (a) increased liver fibrosis scores (FIB-4 and APRI) are associated with liver cancer mortality and (b) the probability that a person with a higher score died of liver cancer. METHODS: In a retrospective occupational cohort who underwent annual/biennial health examinations (between 2002 and 2015), subjects were excluded with known chronic liver disease. Based on their baseline FIB-4 and APRI scores, subjects were categorised in low-/intermediate-/high-risk groups for advanced liver fibrosis. Using Cox proportional hazards regression analyses adjusted hazard ratios (aHR) were estimated for liver cancer mortality, with the low-risk FIB-4/APRI group as the reference. Harrell's C statistics were also calculated. RESULTS: In 200 479 participants, mean (SD) age was 36.4 (7.7) years. Median follow-up was 4.1 years (IQR 2.10-8.03) with 80 liver cancer deaths. High baseline FIB-4 or APRI scores occurred in 0.25% and 0.09% of subjects respectively. A high FIB-4 or APRI score was associated with a markedly increased risk of liver cancer mortality (aHRs 629.10 [95% CI 228.74-1730.20] and 80.42 [95% CI 34.37-188.18]) respectively. C statistics were FIB-4 = 0.841 (95% CI 0.735-0.946) and APRI = 0.933 (95% CI 0.864-0.999). CONCLUSIONS: In a general population without known liver disease, high FIB-4 or high APRI (in keeping with a high probability of advanced fibrosis) occurred in 0.25% (FIB-4) and 0.09% (APRI) of subjects. Both scores were associated with a markedly increased risk of liver cancer mortality and FIB-4 and APRI models both strongly predicted liver cancer mortality.