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BACKGROUND: Registration of research studies is designed to lock investigators into a data collection and analysis plan before a study starts and thereby limit their ability to engage in flexible data analysis and selective outcome reporting. Studies of registered clinical trials show that one- to two-thirds are registered after the study has started and that non-adherence to important design and analytic features, such as reporting data pertaining to all primary outcomes, remains high. Less is known about the effects of registration on research transparency and integrity outside of clinical trials. To address this gap in knowledge, the current study examined the effects of registration on the reporting of research findings in a sample of behavioral health trials published in BMC Public Health. METHODS: Registered trials published in the BMC Public Health section "Health Behavior, Health Promotion and Society" between 2011 and 2015 were included in the study. For each trial, we reviewed associated online submissions from 13 different registration sites. For those determined to have been prospectively registered, we used the trial registry, MEDLINE (Pubmed), PsychINFO, Web of Science and e-mails to investigators to identify subsequent publications from the study that reported results pertaining to primary outcomes. The two investigators then independently reviewed the outcome publication(s) and compared the primary outcomes reported in these to the registered primary outcomes. RESULTS: The final analytic sample comprised 136 locatable, registered trials with an identifiable start date. Sixty-eight of the 136 were prospectively registered. Among these prospectively registered trials, only 16 published manuscripts reported outcomes and methods that were concordant with their registrations. CONCLUSIONS: Retrospective submission of protocols for publication and retrospective registration remain common in public health research, and adherence to prespecified outcomes is rare. In its current form, registration of behavioral and health promotion trials is likely to have minimal effect on preventing selective outcome reporting in publications, and the pervasiveness of vague and incomplete registry entries means that registries will have limited utility in terms of facilitating replication studies.
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Ensaios Clínicos como Assunto , Sistema de Registros , Comportamentos Relacionados com a Saúde , Humanos , Projetos de Pesquisa , Estudos RetrospectivosRESUMO
BACKGROUND: Although rare in the general population, highly penetrant germline mutations in CDKN2A are responsible for 5%-40% of melanoma cases reported in melanoma-prone families. We sought to determine whether MELPREDICT was generalizable to a global series of families with melanoma and whether performance improvements can be achieved. METHODS: In total, 2116 familial melanoma cases were ascertained by the international GenoMEL Consortium. We recapitulated the MELPREDICT model within our data (GenoMELPREDICT) to assess performance improvements by adding phenotypic risk factors and history of pancreatic cancer. We report areas under the curve (AUC) with 95% confidence intervals (CIs) along with net reclassification indices (NRIs) as performance metrics. RESULTS: MELPREDICT performed well (AUC 0.752, 95% CI 0.730-0.775), and GenoMELPREDICT performance was similar (AUC 0.748, 95% CI 0.726-0.771). Adding a reported history of pancreatic cancer yielded discriminatory improvement (P < .0001) in GenoMELPREDICT (AUC 0.772, 95% CI 0.750-0.793, NRI 0.40). Including phenotypic risk factors did not improve performance. CONCLUSION: The MELPREDICT model functioned well in a global data set of familial melanoma cases. Adding pancreatic cancer history improved model prediction. GenoMELPREDICT is a simple tool for predicting CDKN2A mutational status among melanoma patients from melanoma-prone families and can aid in directing these patients to receive genetic testing or cancer risk counseling.
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Inibidor p16 de Quinase Dependente de Ciclina/genética , Predisposição Genética para Doença , Modelos Logísticos , Melanoma/genética , Neoplasias Pancreáticas , Neoplasias Cutâneas/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Criança , Testes Genéticos , Mutação em Linhagem Germinativa , Heterozigoto , Humanos , Internacionalidade , Pessoa de Meia-Idade , Neoplasias Pancreáticas/epidemiologia , Neoplasias Pancreáticas/genética , Fenótipo , Valor Preditivo dos Testes , Probabilidade , Curva ROC , Fatores de Risco , Adulto JovemRESUMO
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
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Although nevus count is an established risk factor for melanoma, relationships between nevus number and patient and tumor characteristics have not been well studied and the influence of nevus count on melanoma-specific survival is equivocal. Using data from the Genes, Environment and Melanoma (GEM) study, a large population-based study of primary cutaneous melanoma, we evaluated associations between number of nevi and patient features, including sun-sensitivity summarized in a phenotypic index, and tumor characteristics. We also assessed the association of nevus count with melanoma-specific survival. Higher nevus counts were independently and positively associated with male gender and younger age at diagnosis, and they were inversely associated with lentigo maligna histology. We observed a borderline significant trend of poorer melanoma-specific survival with increasing quartile of nevus count, but little or no association between number of nevi and pigmentary phenotypic characteristics or prognostic tumor features.
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Melanoma/mortalidade , Melanoma/patologia , Nevo Pigmentado/patologia , Fenótipo , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Melanoma/epidemiologia , Pessoa de Meia-Idade , Razão de Chances , Vigilância da População , Prognóstico , Modelos de Riscos Proporcionais , Fatores de Risco , Neoplasias Cutâneas , Melanoma Maligno CutâneoRESUMO
OBJECTIVES: There is a marked propensity for patients with acetaminophen-induced acute liver failure to develop sepsis, which may culminate in multiple organ failure and death. Toll-like receptors sense pathogens and induce inflammatory responses, but whether this is protective or detrimental in acetaminophen-induced acute liver failure remains unknown. DESIGN, SETTING, AND PATIENTS: We assessed Toll-like receptor expression on circulating neutrophils and their function in 24 patients with acetaminophen-induced acute liver failure and compared with 10 healthy controls. INTERVENTIONS: Neutrophil Toll-like receptor 2, -4, and -9 expression and cytokine production and function were studied ex vivo at baseline and following stimulation with lipopolysaccharide, oligodeoxynucleotides, ammonium chloride, and interleukin-8. To examine the influence of acetaminophen-induced acute liver failure plasma and endogenous DNA on Toll-like receptors-9 expression, healthy neutrophils were incubated with acetaminophen-induced acute liver failure plasma with and without deoxyribonuclease-I. MEASUREMENTS AND MAIN RESULTS: Circulating neutrophil Toll-like receptor 9 expression was increased in acetaminophen-induced acute liver failure on day 1 compared with healthy controls (p = 0.0002), whereas Toll-like receptor 4 expression was decreased compared with healthy controls (p < 0.0001). Toll-like receptor 2 expression was unchanged. Neutrophil phagocytic activity was decreased, and spontaneous oxidative burst increased in all patients with acetaminophen-induced acute liver failure compared with healthy controls (p < 0.0001). Neutrophil Toll-like receptor 9 expression correlated with plasma interleukin-8 and peak ammonia concentration (r = 0.6; p < 0.05) and increased with severity of hepatic encephalopathy (grade 0-2 vs 3/4) and systemic inflammatory response syndrome score (0-1 vs 2-4) (p < 0.05). Those patients with advanced hepatic encephalopathy (grade 3/4) or high systemic inflammatory response syndrome score (2-4) on day 1 had higher neutrophil Toll-like receptor 9 expression, arterial ammonia concentration, and plasma interleukin-8 associated with neutrophil exhaustion. Healthy neutrophil Toll-like receptor 9 expression increased upon stimulation with acetaminophen-induced acute liver failure plasma, which was abrogated by preincubation with deoxyribonuclease-I. Intracellular Toll-like receptor 9 was induced by costimulation with interleukin-8 and ammonia. CONCLUSION: These data point to neutrophil Toll-like receptor 9 expression in acetaminophen-induced acute liver failure being mediated both by circulating endogenous DNA as well as ammonia and interleukin-8 in a synergistic manner inducing systemic inflammation, neutrophil exhaustion, and exacerbating hepatic encephalopathy.
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Acetaminofen/efeitos adversos , Falência Hepática Aguda/induzido quimicamente , Falência Hepática Aguda/imunologia , Neutrófilos/imunologia , Síndrome de Resposta Inflamatória Sistêmica/induzido quimicamente , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Receptor Toll-Like 9/biossíntese , Adulto , Estudos de Coortes , Feminino , Humanos , Falência Hepática Aguda/sangue , Masculino , Pessoa de Meia-Idade , Síndrome de Resposta Inflamatória Sistêmica/sangue , Adulto JovemRESUMO
Melanocortin-1 receptor (MC1R) is a marker of melanoma risk in populations of European ancestry. However, MC1R effects on survival are much less studied. We investigated associations between variation at MC1R and survival in an international, population-based series of single primary melanoma patients enrolled into the Genes, Environment, and Melanoma study. MC1R genotype data was available for 2,200 participants with a first incident primary melanoma diagnosis. We estimated the association of MC1R genotypes with melanoma-specific survival (i.e., death caused by melanoma) and overall survival using COX proportional hazards modeling, adjusting for established prognostic factors for melanoma. We also conducted stratified analyses by Breslow thickness, tumor site, phenotypic index, and age. In addition, we evaluated haplotypes involving polymorphisms near the Agouti signaling protein gene (ASIP) locus for their impacts on survival. Melanoma-specific survival was inversely associated with carriage of MC1R variants in the absence of consensus alleles compared to carriage of at least one consensus allele (hazard ratio (HR) = 0.60; 95% confidence interval (CI): 0.40, 0.90). MC1R results for overall survival were consistent with no association. We did not observe any statistical evidence of heterogeneity of effect estimates in stratified analyses. We observed increased hazard of melanoma-specific death among carriers of the risk haplotype TG near the ASIP locus (HR = 1.37; 95% CI: 0.91, 2.04) when compared to carriers of the most common GG haplotype. Similar results were noted for overall survival. Upon examining the ASIP TG/TG diplotype, we observed considerably increased hazard of melanoma-specific death (HR = 5.11; 95% CI: 1.88, 13.88) compared to carriers of the most common GG/GG diplotype. Our data suggest improved melanoma-specific survival among carriers of two inherited MC1R variants.
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Proteína Agouti Sinalizadora/genética , Melanoma/genética , Melanoma/mortalidade , Receptor Tipo 1 de Melanocortina/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Estudos de Associação Genética , Variação Genética , Genótipo , Hereditariedade , Humanos , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Modelos de Riscos Proporcionais , Adulto JovemRESUMO
AURKA is a putative low-penetrance tumor susceptibility gene due to its prominent role in cell cycle regulation and centrosomal function. Germline variation in AURKA was evaluated for association with breast cancer and intrinsic breast cancer subtypes in the Carolina Breast Cancer Study (CBCS), a population-based case-control study of African Americans (AA) and Caucasians (Cau). Tag and candidate single nucleotide polymorphisms (SNPs) on AURKA were genotyped in 1946 cases and 1747 controls. In race-stratified analyses adjusted for age and African ancestry, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate SNP associations with breast cancer. In a race-combined analysis with similar adjustment, these associations were also examined by intrinsic breast cancer subtype. Using dominant models, most AURKA SNPs demonstrated no association with breast cancer in the race-stratified analyses. Among AA, rs6092309 showed an inverse association with breast cancer (OR = 0.69, 95% CI = 0.53-0.90). In the race-combined analyses, rs6099128 had reduced ORs for luminal A (OR = 0.76, 95% CI = 0.60-0.95) and basal-like breast cancer (OR = 0.54, 95% CI = 0.37-0.80). Rs6092309 showed a similar pattern of association with each subtype. Three SNPs (rs6014711, rs911162, rs1047972) had positive associations with basal-like breast cancer, and ORs reduced or close to 1.00 for other subtypes. Our results suggest inverse associations between some AURKA SNPs and overall breast cancer in AA. We found differential associations by specific subtypes and by race. Replication of these findings in larger AA populations would allow more powerful race-stratified subtype analyses.
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Aurora Quinase A/genética , Neoplasias da Mama/genética , Proteínas de Ciclo Celular/genética , Ciclo Celular/genética , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único/genética , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Genótipo , Humanos , Pessoa de Meia-Idade , Adulto JovemRESUMO
UNLABELLED: Systemic inflammation and susceptibility to developing sepsis is common in acute liver failure (ALF) resulting in tissue damage and organ failure. This study characterized the function of circulating neutrophils in 25 patients with ALF and subacute liver failure (SALF). ALF (n=15)/SALF (n=10) patients were prospectively studied and compared with 11 healthy (HC) and 6 septic controls (SC). Neutrophils were isolated on admission to intensive care and every 3-4 days until death / liver transplantation / recovery. Neutrophil phenotype was determined using fluorochrome-labeled antibodies to CD16 and CD11b and assessed by flow cytometry. Neutrophil phagocytic activity (NPA) was determined using fluorescein isothiocyanate-labeled opsonized Escherichia coli and oxidative burst (OB) was determined by the percentage of neutrophils producing reactive oxygen species (ROS) at rest and after stimulation with opsonized E. coli. Physiological variables, biochemistry, arterial ammonia, microbiology, and outcomes were collected. Plasma pro- and antiinflammatory cytokine profiles were performed by enzyme-linked immunosorbent assay. Neutrophil expression of CD16 which recognizes the FcγRIII region of immunoglobulin G was significantly reduced in the ALF cohort (P<0.001) on day 1 compared to HC. NPA was significantly impaired in the SALF cohort compared to HC (P<0.01). Impaired NPA in the ALF and SALF cohorts on admission predicted nonsurvival without liver transplantation (P=0.01). Spontaneous neutrophil production of ROS was not significantly increased in any of the cohorts. E. coli-stimulated OB was preserved in ALF/SALF cohorts but was significantly impaired in the SC group (P<0.05). CONCLUSION: Circulating neutrophils in ALF/SALF have impaired bacteriocidal function similar to that seen in severe sepsis. Neutrophil function indices are important biomarkers in ALF and may be implicated in the development of organ dysfunction and the increased susceptibility to developing sepsis.
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Falência Hepática Aguda/imunologia , Neutrófilos/imunologia , Explosão Respiratória/imunologia , Sepse/imunologia , Adulto , Idoso , Estudos Transversais , Citocinas/sangue , Feminino , Humanos , Imunofenotipagem , Falência Hepática Aguda/mortalidade , Falência Hepática Aguda/cirurgia , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Neutrófilos/metabolismo , Fagocitose/imunologia , Prognóstico , Estudos Prospectivos , Espécies Reativas de Oxigênio/metabolismo , Sepse/mortalidade , Sepse/patologia , Índice de Gravidade de Doença , Adulto JovemRESUMO
UNLABELLED: Patients with alcohol-related liver disease (ALD) have antibodies directed to alcohol dehydrogenase (ADH), anti-ADH titers being associated with disease severity and active alcohol consumption. ADH-specific T-cell responses have not been characterized. We aimed to define anti-ADH cellular immune responses and their association with active alcohol consumption and disease severity. Using cultures of peripheral blood mononuclear cells (PBMCs) from 25 patients with alcohol-related cirrhosis (ARC; 12 were actively drinking or abstinent for <6 months, and 13 were abstinent for >6 months) and hepatic mononuclear cells (HMCs) from 14 patients with ARC who were undergoing transplantation, we investigated T-cell reactivity to 25 overlapping peptides representing the full human ADH protein (beta 1 subunit). ADH-specific peripheral T-cell responses were assessed by the quantification of T-cell proliferation and cytokine production and were correlated with the clinical course. In active alcohol consumers, proliferative T-cell responses targeted ADH31-95 and other discontinuous sequences in the ADH peptide, whereas only one sequence was targeted in abstinents. ADH peptides induced the production of interferon-γ (IFN-γ), interleukin-4 (IL-4), and IL-17. IL-4 production was lower in active drinkers versus abstinents, and IL-17 production was higher. Peptides inducing IFN-γ production outnumbered those inducing T-cell proliferation. The intensity of the predominantly T helper 1 (Th 1) responses directly correlated with disease severity. Similar to PBMCs in abstinents, ADH peptides induced weak T-cell proliferation and a similar level of IL-4 production in HMCs but less vigorous Th 1 and T helper 17 responses. CONCLUSION: This suggests that Th 1 responses to ADH in ARC are induced by alcohol consumption. A Th 1/T helper 2 imbalance characterizes T-cell responses in active drinkers with ARC, whereas IL-4 production prevails in abstinents. This identifies new targets for immunoregulatory therapies in ALD patients for halting detrimental effector T-cell responses, which may encourage liver fibrogenesis and progression to end-stage liver disease.
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Álcool Desidrogenase/imunologia , Consumo de Bebidas Alcoólicas/imunologia , Cirrose Hepática Alcoólica/imunologia , Linfócitos T/imunologia , Adulto , Idoso , Feminino , Humanos , Interferon gama/biossíntese , Interleucina-17/biossíntese , Interleucina-4/biossíntese , Leucócitos Mononucleares/metabolismo , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/farmacologia , Temperança , Células Th1/imunologiaRESUMO
Molecules labeled with fluorine-18 are used as radiotracers for positron emission tomography. An important challenge is the labeling of arenes not amenable to aromatic nucleophilic substitution (SNAr) with [(18)F]F(-). In the ideal case, the (18)Fâ fluorination of these substrates would be performed through reaction of [(18)F]KF with shelf-stable readily available precursors using a broadly applicable method suitable for automation. Herein, we describe the realization of these requirements with the production of (18)Fâ arenes from pinacol-derived aryl boronic esters (arylBPin) upon treatment with [(18)F]KF/K222 and [Cu(OTf)2(py)4] (OTf = trifluoromethanesulfonate, py = pyridine). This method tolerates electron-poor and electron-rich arenes and various functional groups, and allows access to 6-[(18)F]fluoro-L-DOPA, 6-[(18)F]fluoro-m-tyrosine, and the translocator protein (TSPO) PET ligand [(18)F]DAA1106.
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Cobre/química , Radioisótopos de Flúor/química , Halogenação/fisiologia , Tomografia por Emissão de Pósitrons/métodos , Estrutura MolecularRESUMO
BACKGROUND & AIMS: The incidence of cirrhosis and subsequent development of organ dysfunction (OD) requiring intensive care unit (ICU) support is rising. Historically, critically ill cirrhotics are perceived as having poor prognosis and substantial cost of care. METHODS: The aim was to prospectively analyse resource utilisation and cost of a large cohort of patients (n=660) admitted to a Liver ICU from 2000 to 2007 with cirrhosis and OD. Child Pugh, MELD, SOFA, APACHE II, and organ support requirements were collected. The Therapeutic Intervention Scoring System (TISS) score, a validated tool for estimating cost in ICU, was calculated daily. Logistic regression was used to determine independent predictors of increased cost. RESULTS: Alcohol was the most common etiology (47%) and variceal bleeding (VB) the most common reason for admission (35%). Invasive ventilatory support was required in 74% of cases, vasopressors in 49%, and 50% required renal replacement therapy. Forty-nine per cent of non-transplanted patients survived to ICU discharge. Median TISS score and ICU cost per patient were 261 and 14,139, respectively. VB patients had the highest survival rates (53% vs. 24%; p<0.001) and lower associated cost. A combination of VB (OR 0.48), need for ventilation (OR 2.81), low PO(2)/FiO(2) on admission (OR 0.97), and lactate (OR 0.93) improved cost prediction on multivariate analysis (AUROC 0.7; p<0.001) but organ failure scores per se were poor predictors of cost. CONCLUSIONS: Patients with cirrhosis and OD result in considerable resource expenditure but have acceptable hospital survival. Further health economic assessment and outcome prediction tools are required to appropriately target resource utilisation.
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Custos de Cuidados de Saúde , Cirrose Hepática/economia , Cirrose Hepática/fisiopatologia , Fígado/fisiopatologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Análise Custo-Benefício , Feminino , Recursos em Saúde/estatística & dados numéricos , Humanos , Unidades de Terapia Intensiva/economia , Cirrose Hepática/mortalidade , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Estudos Retrospectivos , Taxa de Sobrevida , Adulto JovemRESUMO
Hepatic encephalopathy (HE) constitutes a neuropsychiatric syndrome which remains a major clinical problem in patients with cirrhosis. In the severest form of HE, cirrhotic patients may develop varying degrees of confusion and coma. Ammonia has been regarded as the key precipitating factor in HE, and astrocytes have been the most commonly affected cells neuropathologically. Although the evidence base supporting a pivotal role of ammonia is robust, in everyday clinical practice a consistent correlation between the concentration of ammonia in the blood and the manifest symptoms of HE is not observed. More recently the synergistic role of inflammation and infection in modulating the cerebral effects of ammonia has been shown to be important. Furthermore, it has been recognized that infection impairs brain function both in the presence and absence of liver disease. Thus it could be postulated that in the presence of ammonia, the brain is sensitized to a systemic inflammatory stimulus and is able to elicit an inflammatory response involving both proinflammatory and neurotransmitter pathways. Ammonia is not only directly toxic to astrocytes but induces neutrophil dysfunction with the release of reactive oxygen species, which contribute to oxidative stress and systemic inflammation. This may further exacerbate the cerebral effects of ammonia and potentially reduce the capacity of the neutrophil to fight microbial attack, thus inducing a vicious circle. This evidence supports the neutrophil in addition to ammonia as being culpable in the pathogenesis of HE, making the neutrophil a target for future anti-inflammatory therapeutic strategies in addition to ammonia lowering therapies.
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Amônia/efeitos adversos , Encefalopatia Hepática/virologia , Cirrose Hepática/complicações , Neutrófilos/fisiologia , Animais , HumanosRESUMO
Positron emission tomography (PET) is a diagnostic nuclear imaging modality that relies on automated protocols to prepare agents labeled with a positron-emitting radionuclide (e.g., 18F). In recent years, new reactions have appeared for the 18F-labeling of agents that are difficult to access by applying traditional radiochemistry, for example those requiring 18F incorporation into unactivated (hetero)arenes. However, automation of these new methods for translation to the clinic has progressed slowly because extensive modification of manual protocols is typically required when implementing novel 18F-labeling methodologies within automated modules. Here, we describe the workflow that led to the automated radiosynthesis of the poly(ADP-ribose) polymerase (PARP) inhibitor [18F]olaparib. First, we established a robust manual protocol to prepare [18F]olaparib from the protected N-[2-(trimethylsilyl)ethoxy]methyl (SEM) arylboronate ester precursor in a 17% ± 5% (n = 15; synthesis time, 135 min) non-decay-corrected (NDC) activity yield, with molar activity (Am) up to 34.6 GBq/µmol. Automation of the process, consisting of copper-mediated 18F-fluorodeboronation followed by deprotection, was achieved on an Eckert & Ziegler Modular-Lab radiosynthesis platform, affording [18F]olaparib in a 6% ± 5% (n = 3; synthesis time, 120 min) NDC activity yield with Am up to 319 GBq/µmol.
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Técnicas de Química Sintética/métodos , Cobre/química , Radioisótopos de Flúor/química , Ftalazinas , Piperazinas , Inibidores de Poli(ADP-Ribose) Polimerases , Automação , Ftalazinas/síntese química , Ftalazinas/química , Piperazinas/síntese química , Piperazinas/química , Inibidores de Poli(ADP-Ribose) Polimerases/síntese química , Inibidores de Poli(ADP-Ribose) Polimerases/química , Tomografia por Emissão de Pósitrons , Radioquímica , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/químicaRESUMO
BACKGROUND: Melanoma causes the vast majority of deaths attributable to skin cancer, largely due to its propensity for metastasis. To date, few studies have examined molecular changes between primary cutaneous melanoma and adjacent putatively normal skin. To broaden temporal inferences related to initiation of disease, we performed a metabolomics investigation of primary melanoma and matched extratumoral microenvironment (EM) tissues; and, to make inferences about progressive disease, we also compared unmatched metastatic melanoma tissues to EM tissues. METHODS: Ultra-high performance liquid chromatography-mass spectrometry-based metabolic profiling was performed on frozen human tissues. RESULTS: We observed 824 metabolites as differentially abundant among 33 matched tissue samples, and 1,118 metabolites as differentially abundant between metastatic melanoma (n = 46) and EM (n = 34) after false discovery rate (FDR) adjustment (p<0.01). No significant differences in metabolite abundances were noted comparing primary and metastatic melanoma tissues. CONCLUSIONS: Overall, pathway-based results significantly distinguished melanoma tissues from EM in the metabolism of: ascorbate and aldarate, propanoate, tryptophan, histidine, and pyrimidine. Within pathways, the majority of individual metabolite abundances observed in comparisons of primary melanoma vs. EM and metastatic melanoma vs. EM were directionally consistent. This observed concordance suggests most identified compounds are implicated in the initiation or maintenance of melanoma.
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Melanoma , Metaboloma , Neoplasias Cutâneas , Microambiente Tumoral , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromatografia Líquida de Alta Pressão/métodos , Feminino , Humanos , Masculino , Espectrometria de Massas/métodos , Melanoma/metabolismo , Melanoma/secundário , Metabolômica/métodos , Pessoa de Meia-Idade , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/secundário , Adulto Jovem , Melanoma Maligno CutâneoRESUMO
A regiocontrolled intermolecular Diels-Alder reaction of an o-benzoquinone followed by an intramolecular nitrile oxide cyclization is employed to prepare the BCD fragment of viridin. The AE segment is attached to it by means of an intramolecular Diels-Alder reaction of an o-benzoquinone monoketal generated in situ from tricycle 15 and 5-trimethylsilyl-2E,4E-pentadienol 20. The silyl substituent at C-1 of the pentacyclic product directs the dihydroxylation of the C2-C3 double bond to its beta-face. Various transformations of the 1alpha-trimethylsilyl-2beta,3beta-dihydroxy pentacycle into several others with oxygen substituents in ring A are described. One of these products 40 possesses the same structure and relative stereochemistry in rings A, B, and E as that of the natural product wortmannolone 3.
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Androstadienos/síntese química , Androstenos/síntese química , Bacteriocinas/síntese química , Inibidores de Proteínas Quinases/síntese química , Androstadienos/química , Androstenos/química , Bacteriocinas/química , Benzoquinonas/química , Ciclização , Estrutura Molecular , Inibidores de Proteínas Quinases/química , Estereoisomerismo , WortmaninaRESUMO
An efficient three-step construction of the highly oxygenated D-ring of the kinamycin antibiotics is reported for a simple model system. A comparison of the spectroscopic characteristics of the synthetic models with those of natural kinamycin F, which is suspected to be the bioactive form of the kinamycins, leads to the conclusion that the favored D-ring conformation of kinamycin F differs from that of the other partially or fully acylated variants.
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Antibacterianos/química , Antibacterianos/síntese química , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Quinonas/síntese química , Quinonas/química , Streptomyces/químicaRESUMO
The tendency for carbocyclic analogues of penicillins to undergo hydrate and hemiketal formation is central to their ability to function as beta-lactamase inhibitors. 2-Thiabicyclo[3.2.0]heptan-6-one-4-carboxylates with alkoxy functionality at C3 have been prepared through two complementary diastereoselective substitution reactions following a highly stereoselective chlorination with sulfuryl chloride. We have found that carbocyclic analogues with 3beta substituents favor an endo envelope conformation in solution, the solid state, and the gas phase, whereas those with 3alpha substituents adopt an exo envelope. Evidence from X-ray crystal structures and ab initio calculations suggests that an anomeric effect contributes to the large conformational preference of the tetrahydrothiophene ring that favors the C3 substituent in an axial orientation. In addition, the envelope conformation of the bicycle, which is determined by the stereochemistry of the C3 substituent, has a dramatic effect on the ability of the cyclobutanone to undergo hemiketal formation in methanol-d4.