Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 153
Filtrar
1.
Nature ; 604(7905): 292-297, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35189623

RESUMO

Recent research in medicinal chemistry has suggested that there is a correlation between an increase in the fraction of sp3 carbons-those bonded to four other atoms-in drug candidates and their improved success rate in clinical trials1. As such, the development of robust and selective methods for the construction of carbon(sp3)-carbon(sp3) bonds remains a critical problem in modern organic chemistry2. Owing to the broad availability of alkyl halides, their direct cross-coupling-commonly known as cross-electrophile coupling-provides a promising route towards this objective3-5. Such transformations circumvent the preparation of carbon nucleophiles used in traditional cross-coupling reactions, as well as stability and functional-group-tolerance issues that are usually associated with these reagents. However, achieving high selectivity in carbon(sp3)-carbon(sp3) cross-electrophile coupling remains a largely unmet challenge. Here we use electrochemistry to achieve the differential activation of alkyl halides by exploiting their disparate electronic and steric properties. Specifically, the selective cathodic reduction of a more substituted alkyl halide gives rise to a carbanion, which undergoes preferential coupling with a less substituted alkyl halide via bimolecular nucleophilic substitution to forge a new carbon-carbon bond. This protocol enables efficient cross-electrophile coupling of a variety of functionalized and unactivated alkyl electrophiles in the absence of a transition metal catalyst, and shows improved chemoselectivity compared with existing methods.

2.
Immunity ; 44(5): 1177-89, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-27178469

RESUMO

Self-DNA is present in the cytosol of many cancer cells and can promote effective immune rejection of tumor cells, but the mechanisms leading to the presence of cytosolic DNA are unknown. Here, we report that the cleavage of genomic DNA by DNA structure-specific endonuclease MUS81 and PARP-dependent DNA repair pathways leads to the accumulation of cytosolic DNA in prostate cancer cells. The number of nuclear MUS81 foci and the amount of cytosolic dsDNA increased in tandem from hyperplasia to clinical stage II prostate cancers and decreased at stage III. Cytosolic DNA generated by MUS81 stimulated DNA sensor STING-dependent type I interferon (IFN) expression and promoted phagocytic and T cell responses, resulting in type I and II IFN-mediated rejection of prostate tumor cells via mechanisms that partly depended on macrophages. Our results demonstrate that the tumor suppressor MUS81 alerts the immune system to the presence of transformed host cells.


Assuntos
Autoantígenos/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Endonucleases/metabolismo , Neoplasias da Próstata/imunologia , Linfócitos T/imunologia , Animais , Autoantígenos/imunologia , Linhagem Celular Tumoral , DNA/imunologia , Humanos , Interferon Tipo I/metabolismo , Ativação Linfocitária , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estadiamento de Neoplasias , Neoplasias Experimentais , Fagocitose , Neoplasias da Próstata/patologia
3.
J Card Fail ; 30(2): 350-358, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37150502

RESUMO

PURPOSE: To describe contemporary management and outcomes in children with myocarditis who are admitted to a cardiac intensive care unit (CICU) and to identify the characteristics associated with mortality. METHODS: All patients in the Pediatric Cardiac Critical Care Consortium (PC4) registry between August 2014 and June 2021 who were diagnosed with myocarditis were included. Univariable analyses and multivariable logistic regression evaluated the factors associated with in-hospital mortality. RESULTS: There were 847 CICU admissions for myocarditis in 51 centers. The median age was 12 years (IQR 2.7-16). In-hospital mortality occurred in 53 patients (6.3%), and 60 (7.1%) had cardiac arrest during admission. Mechanical ventilation was required in 339 patients (40%), and mechanical circulatory support (MCS) in 177 (21%); extracorporeal membrane oxygenation (ECMO)-only in 142 (16.7%), ECMO-to-ventricular assist device (VAD) in 20 (2.4%), extracorporeal cardiac resuscitation in 43 (5%), and VAD-only in 15 (1.8%) patients. MCS was associated with in-hospital mortality; 20.3% receiving MCS died compared to 2.5% without MCS (P < 0.001). Mortality rates were similar in ECMO-only, ECMO-to-VAD and VAD-only groups. The median time from CICU admission to ECMO was 2.0 hours (IQR 0-9.4) and to VAD, it was 9.9 days (IQR 6.3-16.8). Time to MCS was not associated with mortality. In multivariable modeling of patients' characteristics, smaller body surface area (BSA) and low eGFR were independently associated with mortality, and after including critical therapies, mechanical ventilation and ECMO were independent predictors of mortality. CONCLUSION: This contemporary cohort of children admitted to CICUs with myocarditis commonly received high-resource therapies; however, most patients survived to hospital discharge and rarely received VAD. Smaller patient size, acute kidney injury and receipt of mechanical ventilation or ECMO were independently associated with mortality.


Assuntos
Insuficiência Cardíaca , Coração Auxiliar , Miocardite , Criança , Humanos , Miocardite/diagnóstico , Miocardite/terapia , Miocardite/complicações , Insuficiência Cardíaca/terapia , Estado Terminal , Estudos Retrospectivos , Coração
4.
Conserv Biol ; 38(2): e14162, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37551767

RESUMO

Trade in pangolins is illegal, and yet tons of their scales and products are seized at various ports. These large seizures are challenging to process and comprehensively genotype for upstream provenance tracing and species identification for prosecution. We implemented a scalable DNA barcoding pipeline in which rapid DNA extraction and MinION sequencing were used to genotype a substantial proportion of pangolin scales subsampled from 2 record shipments seized in Singapore in 2019 (37.5 t). We used reference sequences to match the scales to phylogeographical regions of origin. In total, we identified 2346 cytochrome b (cytb) barcodes of white-bellied (Phataginus tricuspis) (from 1091 scales), black-bellied (Phataginus tetradactyla) (227 scales), and giant (Smutsia gigantea) (1028 scales) pangolins. Haplotype diversity was higher for P. tricuspis scales (121 haplotypes, 66 novel) than that for P. tetradactyla (22 haplotypes, 15 novel) and S. gigantea (25 haplotypes, 21 novel) scales. Of the novel haplotypes, 74.2% were likely from western and west-central Africa, suggesting potential resurgence of poaching and newly exploited populations in these regions. Our results illustrate the utility of extensively subsampling large seizures and outline an efficient molecular approach for rapid genetic screening that should be accessible to most forensic laboratories and enforcement agencies.


Revelación de la magnitud de la caza furtiva del pangolín africano mediante el genotipo extenso de nanoporos de ADN de escamas incautadas Resumen Aunque el mercado de pangolines es ilegal, se incautan toneladas de sus escamas y productos derivados en varios puertos comerciales. Es un reto procesar estas magnas incautaciones y obtener el genotipo completo para usarlo en la trazabilidad logística ascendente e identificación de la especie y así imponer sanciones. Implementamos una canalización escalable del código de barras de ADN en el cual usamos la extracción rápida de ADN y la secuenciación MinION para obtener el genotipo de una proporción sustancial de las escamas de pangolín submuestreadas en dos cargamentos incautados en 2019 en Singapur (37.5 t). Usamos secuencias referenciales para emparejar las escamas con las regiones filogeográficas de origen. Identificamos en total 2,346 códigos de citocromo b (cytb) del pangolín de vientre blanco (Phataginus tricuspis) (de 1,091 escamas), de vientre negro (P. tetradactyla) (227 escamas) y del pangolín gigante (Smutsia gigantea) (1,028 escamas). La diversidad de haplotipos fue mayor en las escamas de P. tricuspis (121 haplotipos, 66 nuevos) que en las de P. tetradactyla (22 haplotipos, 15 nuevos) y S. gigantea (25 haplotipos, 21 nuevos). De los haplotipos nuevos, el 74.2% probablemente provenía del occidente y centro­occidente de África, lo que sugiere un resurgimiento potencial de la caza furtiva y poblaciones recién explotadas en estas regiones. Nuestros resultados demuestran la utilidad de submuestrear extensivamente las grandes incautaciones y esboza una estrategia molecular eficiente para un análisis genético rápido que debería ser accesible para la mayoría de los laboratorios forenses y las autoridades de aplicación.


Assuntos
Nanoporos , Pangolins , Humanos , Animais , Genótipo , Conservação dos Recursos Naturais/métodos , DNA , Convulsões
5.
J Am Acad Dermatol ; 90(6): 1232-1239, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38266683

RESUMO

BACKGROUND: Approved systemic treatment options are limited for pediatric patients with moderate to severe plaque psoriasis. OBJECTIVE: To assess the efficacy and safety of apremilast over 16 weeks in pediatric patients with plaque psoriasis. METHODS: SPROUT (NCT03701763) was a phase 3, multicenter, randomized, double-blind, placebo-controlled study of apremilast in patients aged 6-17 years with moderate-to-severe psoriasis (Psoriasis Area and Severity Index [PASI] ≥12, body surface area ≥10%, static Physician Global Assessment [sPGA] ≥3) inadequately controlled by/inappropriate for topical therapy. Patients were stratified by age group and randomized (2:1) to apremilast (20 or 30 mg BID based on weight) or placebo for 16 weeks, followed by apremilast extension to 52 weeks. RESULTS: Of 245 patients randomized (apremilast: 163; placebo: 82), 221 (90%) completed the double-blind phase (apremilast: 149; placebo: 72). Significantly more patients achieved sPGA response and ≥75% reduction in PASI with apremilast than placebo, regardless of baseline age, weight, or disease severity. No new safety signals were observed. LIMITATIONS: Sample size of subgroup analyses. CONCLUSIONS: Improvements in global disease activity and skin involvement were significantly greater in pediatric patients treated with apremilast versus placebo. Adverse events were consistent with the known apremilast safety profile.


Assuntos
Anti-Inflamatórios não Esteroides , Psoríase , Índice de Gravidade de Doença , Talidomida , Humanos , Talidomida/análogos & derivados , Talidomida/uso terapêutico , Talidomida/efeitos adversos , Talidomida/administração & dosagem , Psoríase/tratamento farmacológico , Adolescente , Criança , Método Duplo-Cego , Masculino , Feminino , Anti-Inflamatórios não Esteroides/uso terapêutico , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/efeitos adversos , Resultado do Tratamento , Inibidores da Fosfodiesterase 4/efeitos adversos , Inibidores da Fosfodiesterase 4/uso terapêutico , Inibidores da Fosfodiesterase 4/administração & dosagem , Relação Dose-Resposta a Droga
6.
J Am Chem Soc ; 145(41): 22298-22304, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37801465

RESUMO

The cross-electrophile dialkylation of alkenes enables the formation of two C(sp3)-C(sp3) bonds from readily available starting materials in a single transformation, thereby providing a modular and expedient approach to building structural complexity in organic synthesis. Herein, we exploit the disparate electronic and steric properties of alkyl halides with varying degrees of substitution to accomplish their selective activation and addition to alkenes under electrochemical conditions. This method enables regioselective dialkylation of alkenes without the use of a transition-metal catalyst and provides access to a diverse range of synthetically useful compounds.

7.
Chemistry ; 29(46): e202301045, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37309269

RESUMO

Samarium diiodide (SmI2 ) is widely used as a strong one-electron reducing agent and is often employed to form C-C bonds in complex systems. Despite their utility, SmI2 and related salts suffer from several drawbacks that render the use of Sm reducing agents in large-scale synthesis impractical. Here, we report factors influencing the electrochemical reduction of Sm(III) to Sm(II), towards the goal of electrocatalytic Sm(III) reduction. We probe the effect of supporting electrolyte, electrode material, and Sm precursor on Sm(II)/(III) redox and on the reducing power of the Sm species. We find that the coordination strength of the counteranion of the Sm salt affects the reversibility and redox potential of the Sm(II)/(III) couple and establish that the counteranion primarily determines the reducibility of Sm(III). Electrochemically generated SmI2 performs similarly to commercial SmI2 solutions in a proof-of-concept reaction. The results will provide fundamental insight to facilitate the development of Sm-electrocatalytic reactions.

8.
Int J Hyperthermia ; 40(1): 2251734, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37654021

RESUMO

OBJECTIVE: To observe the characteristics of a new extracorporeal high intensity focused ultrasound transducer, titled Haifu system JCQ-B, and to compare its safety and efficacy for breast ablation with the standard Haifu system JC transducer. MATERIALS AND METHODS: Ox liver with pig skin and pork ribs were prepared in a semi-sphere shape, served as in vitro acoustic model. The udders of female goats were used as in vivo acoustic model. Both in vitro and in vivo models were ablated by either JCQ-B or JC transducer. The morphology of biological focal region (BFR), the coagulative necrosis volume, and the temperature increase were observed and compared. RESULTS: The BFR morphology of JCQ-B transducer was circular both in vitro and in vivo, with a length-width ratio close to one. Under the same sonication parameters (sonication power, time and depth in tissue), coagulation necrosis volume caused by JCQ-B transducer was larger than that caused by JC transducer both in vitro and in vivo. The increase in temperature in the near and far acoustic pathways with JCQ-B transducer was significantly lower than that of JC transducer in vitro. After receiving high sonication energy during in vivo experimentation, there were no complications observed after the ablation of JCQ-B transducer, while small skin damage was observed after the ablation of JC transducer. CONCLUSIONS: The JCQ-B transducer improved the safety and efficacy of treatment by optimizing BFR morphology and ablation efficiency, which could be applied in the treatment of breast tumor.


Assuntos
Neoplasias da Mama , Ablação por Ultrassom Focalizado de Alta Intensidade , Feminino , Animais , Suínos , Humanos , Fígado/cirurgia , Necrose , Transdutores
9.
J Community Health ; 48(5): 903-911, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37284919

RESUMO

Primary care providers in Prince George's County, Maryland reported inconsistencies in their ability to identify and refer patients with social care needs. This project aimed to improve health outcomes of Medicare beneficiaries by implementing social determinant of health (SDOH) screening to identify unmet needs and improve rates of referral to appropriate services. Buy-in was achieved from providers and frontline staff via stakeholder meetings at a private primary care group practice. The Health Leads questionnaire was modified and integrated into the electronic health record. Medical assistants (MA) were trained to conduct screening and initiate care plan referrals prior to visits with the medical provider. During implementation, 96.25% of patients (n = 231) agreed to screening. Of these, 13.42% (n = 31) screened positive for at least one SDOH need, and 48.39% (n = 15) reported multiple social needs. Top needs included social isolation (26.23%), literacy (16.39%), and financial concerns (14.75%). All patients screening positive for one or more social needs were provided referral resources. Patients who identified as being of Mixed or Other race had significantly higher rates of positive screens (p = 0.032) compared to Caucasians, African Americans, and Asians. Patients were more likely to report SDOH needs during in-person visits (17.22%) compared to telehealth visits (p = 0.020). Screening for SDOH needs is feasible and sustainable and can improve the identification of SDOH needs and resource referrals. A limitation of this project was the lack of follow-up to determine whether patients with positive SDOH screens had been successfully linked to resources after initial referral.


Assuntos
COVID-19 , Determinantes Sociais da Saúde , Humanos , Idoso , Estados Unidos/epidemiologia , Maryland/epidemiologia , Pandemias , Medicare , COVID-19/epidemiologia , Atenção Primária à Saúde
10.
J Assist Reprod Genet ; 40(5): 1055-1062, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37000344

RESUMO

PURPOSE: To assess the impact of elevated BMI on the success of modified natural cycle frozen embryo transfers (mNC-FET) of euploid embryos. METHODS: This retrospective cohort study at a single academic institution reviewed mNC-FET involving single euploid blastocysts from 2016 to 2020. Comparison groups were divided by pre-pregnancy BMI (kg/m2) category: normal weight (18.5-24.9), overweight (25-29.9) or obese (≥ 30). Underweight BMI (< 18.5) was excluded from the analysis. The primary outcome was live birth rate (LBR) and secondary outcome was clinical pregnancy rate (CPR), defined as presence of fetal cardiac activity on ultrasound. Absolute standardized differences (ASD) were calculated to compare descriptive variables and p-values and multivariable logistic regressions with generalized estimating equations (GEE) were used to compare pregnancy outcomes. RESULTS: 562 mNC-FET cycles were completed in 425 patients over the study period. Overall, there were 316 transfers performed in normal weight patients, 165 in overweight patients, and 81 in obese weight patients. There was no statistically significant difference in LBR across all BMI categories (55.4% normal weight, 61.2% overweight, and 64.2% obese). There was also no difference for the secondary outcome, CPR, across all categories (58.5%, 65.5%, and 66.7%, respectively). This was confirmed in GEE analysis when adjusting for confounders. CONCLUSION: While increased weight has commonly been implicated in poor pregnancy outcomes, the effect of BMI on the success of mNC-FET remains debated. Across five years of data from a single institution using euploid embryos in mNC-FET cycles, elevated BMI was not associated with reduced LBR or CPR.


Assuntos
Coeficiente de Natalidade , Sobrepeso , Gravidez , Feminino , Humanos , Taxa de Gravidez , Estudos Retrospectivos , Índice de Massa Corporal , Criopreservação , Transferência Embrionária , Obesidade , Nascido Vivo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa