Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 388
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Nature ; 610(7933): 680-686, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36049504

RESUMO

Research in the field of asymmetric catalysis over the past half century has resulted in landmark advances, enabling the efficient synthesis of chiral building blocks, pharmaceuticals and natural products1-3. A small number of asymmetric catalytic reactions have been identified that display high selectivity across a broad scope of substrates; not coincidentally, these are the reactions that have the greatest impact on how enantioenriched compounds are synthesized4-8. We postulate that substrate generality in asymmetric catalysis is rare not simply because it is intrinsically difficult to achieve, but also because of the way chiral catalysts are identified and optimized9. Typical discovery campaigns rely on a single model substrate, and thus select for high performance in a narrow region of chemical space. Here we put forth a practical approach for using multiple model substrates to select simultaneously for both enantioselectivity and generality in asymmetric catalytic reactions from the outset10,11. Multisubstrate screening is achieved by conducting high-throughput chiral analyses by supercritical fluid chromatography-mass spectrometry with pooled samples. When applied to Pictet-Spengler reactions, the multisubstrate screening approach revealed a promising and unexpected lead for the general enantioselective catalysis of this important transformation, which even displayed high enantioselectivity for substrate combinations outside of the screening set.


Assuntos
Produtos Biológicos , Técnicas de Química Sintética , Preparações Farmacêuticas , Produtos Biológicos/síntese química , Produtos Biológicos/química , Catálise , Preparações Farmacêuticas/síntese química , Preparações Farmacêuticas/química , Estereoisomerismo , Especificidade por Substrato , Cromatografia com Fluido Supercrítico , Espectrometria de Massas , Técnicas de Química Sintética/métodos
2.
Development ; 150(21)2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37787076

RESUMO

Reciprocal interactions between non-myocytes and cardiomyocytes regulate cardiac growth and differentiation. Here, we report that the transcription factor Ebf1 is highly expressed in non-myocytes and potently regulates heart development. Ebf1-deficient hearts display myocardial hypercellularity and reduced cardiomyocyte size, ventricular conduction system hypoplasia, and conduction system disease. Growth abnormalities in Ebf1 knockout hearts are observed as early as embryonic day 13.5. Transcriptional profiling of Ebf1-deficient embryonic cardiac non-myocytes demonstrates dysregulation of Polycomb repressive complex 2 targets, and ATAC-Seq reveals altered chromatin accessibility near many of these same genes. Gene set enrichment analysis of differentially expressed genes in cardiomyocytes isolated from E13.5 hearts of wild-type and mutant mice reveals significant enrichment of MYC targets and, consistent with this finding, we observe increased abundance of MYC in mutant hearts. EBF1-deficient non-myocytes, but not wild-type non-myocytes, are sufficient to induce excessive accumulation of MYC in co-cultured wild-type cardiomyocytes. Finally, we demonstrate that BMP signaling induces Ebf1 expression in embryonic heart cultures and controls a gene program enriched in EBF1 targets. These data reveal a previously unreported non-cell-autonomous pathway controlling cardiac growth and differentiation.


Assuntos
Regulação da Expressão Gênica , Fatores de Transcrição , Animais , Camundongos , Diferenciação Celular/genética , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Fatores de Transcrição/metabolismo
3.
Bioorg Chem ; 148: 107468, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38781670

RESUMO

A new efficient and versatile one-pot three-component synthesis of substituted pyrrolo[1,2-a]thieno[3,2-e]pyrimidine derivatives has been developed. It is based on a multistep cascade reaction from 2-aminothiophenes and 2-hydroxy-4-oxobut-2-enoic acids, and derivatives of cyanoacetic acid catalyzed by diisopropylethylamine. As a result, novel pyrrolo[1,2-a]thieno[3,2-e]pyrimidine derivatives (21 compounds) were synthesized in a mild reaction conditions with a high yield. The structures of the developed compounds were confirmed by NMR and elemental analysis. The influence of electron-withdrawing or electron-donor substituents on the antitumor activity of the developed compounds has been identified. In vitro screening analysis of 21 compounds revealed six lead candidates (12aa, 12dc, 12hc, 12ic, 12lb, and 12mb) that demonstrated the most significant antitumor activity against B16-F10, 4T1 and CT26 cells. Necrosis/apoptosis assay showed that apoptosis was the predominant mechanism of cell death. Molecular docking analysis revealed several potential targets for tested compounds, i.e. phosphatidylinositol 5-phosphate 4-kinase (PI5P4K2C), proto-oncogene serine/threonine-protein kinase (Pim-1), nicotinamide phosphoribosyltransferase (NAMPT) and dihydrofolate reductase (DHFR). The lead compound (12aa) can effectively induce cell apoptosis, possesses a high yield (98 %) and requires low-cost starting chemicals for its synthesis. In vivo experiments with melanoma-bearing mice confirmed that 12aa compound resulted in the significant tumor inhibition on 15 d after the therapy. In particular, tumor volume was ∼0.19 cm3 for 50 mg/kg versus ∼2.39 cm3 in case of untreated mice and tumor weight was ∼71.6 mg for 50 mg/kg versus ∼452.4 mg when considered untreated mice. Thus, our results demonstrated the high potential of the 12aa compound in the treatment of melanoma and can be recommended for further preclinical studies.


Assuntos
Antineoplásicos , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Pirimidinas , Pirróis , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Animais , Pirimidinas/química , Pirimidinas/síntese química , Pirimidinas/farmacologia , Camundongos , Relação Estrutura-Atividade , Estrutura Molecular , Humanos , Pirróis/química , Pirróis/farmacologia , Pirróis/síntese química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Linhagem Celular Tumoral , Simulação de Acoplamento Molecular , Proto-Oncogene Mas , Apoptose/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/patologia , Melanoma Experimental/metabolismo
4.
Angew Chem Int Ed Engl ; 63(1): e202315284, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-37956221

RESUMO

The discorhabdin natural products are a large subset of pyrroloiminoquinone alkaloids with a myriad of biological activities. Despite garnering much synthetic attention, few members have thus far been completed, particularly those featuring a bridging carbon-nitrogen bond that is found in numerous discorhabdins, including discorhabdin V. Herein we report the first total synthesis and full stereochemical assignment of (+)-discorhabdin V. To access the pyrroloiminoquinone we developed a convergent N-alkylation/oxidative aminocyclization/bromination cascade that joins two key components, which are both made on multigram scale. An intramolecular Heck reaction then forms the quaternary carbon center in an intermediate containing the carbon-nitrogen bridge, and a reductive N,O-acetal cyclization sequence introduces the final piperidine ring. Furthermore, we have established the relative configuration of (+)-discorhabdin V through experimental NOESY data and DP4 NMR probability calculations. The absolute configuration of the natural product has also been determined by circular dichroism and the use of an amino acid derived chiral starting material. Our work represents one of only two reports of a total synthesis of a nitrogen-bridged discorhabdin and paves the way for future biological evaluation of such compounds.

5.
Arch Microbiol ; 205(5): 214, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37129715

RESUMO

Bacteriophages are often considered as possible agents of biological control of unwanted bacterial populations in medicine, agriculture and food industry. Although the virulent phages can efficiently kill the infected host cells but at the population level phage attack not always leads to the host population collapse but may result in establishment of a more or less stable co-existence. The mechanism of the long-term stabilization of the mixed phage-host cultures is poorly understood. Here we describe bacteriophages VyarbaL and Hena2, the members of the Molineuxvirinae and the Ounavirinae subfamilies, respectively, that are able to form the pseudolysogenic associations (PA) with their host Erwinia amylovora 1/79Sm on solid media. These PAs were stable through multiple passages. The phenomenon of the PA formation between a bacterial culture and bacteriophages decreases the effectiveness of bacteriophage-mediated biological control agents based on lytic bacteriophages.


Assuntos
Bacteriófagos , Erwinia amylovora , Humanos , Myoviridae , Bactérias , Doenças das Plantas/microbiologia
6.
Ann Plast Surg ; 91(5): 529-533, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37823619

RESUMO

BACKGROUND: We performed an assessment of patient response rates and clinical outcomes to the global recall for textured breast implants and to our institution's letters informing them of their risk of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). METHODS: A retrospective review of patients who had textured implants placed at our institution was completed. Outcome measures included patient response rates to either the global recall or our institution's letters, rate of textured implant removal, and type of subsequent revision surgery. RESULTS: A total of 1176 patients with textured implants were reviewed for this study. In total, 374 patients (31.8%) reached out to discuss their risk of BIA-ALCL, and 297 (25.3%) eventually presented to the clinic. One hundred twenty eight patients (34.2%) responded after the letter but before the US Food and Drug Administration (FDA) ban of macrotextured BIOCELL implants, 186 (49.7%) after the FDA ban, and 48 (12.8%) after the manufacturer's multichannel campaign. One hundred eighteen patients with textured implants (11.6%) proceeded with surgery. Most underwent exchange with smooth implants (76 patients [64.4%]) after textured implant removal. CONCLUSIONS: A significant portion of patients (31.8%) responded to our letters, the FDA ban, and the manufacturer's campaign. Despite the low incidence of BIA-ALCL and the ongoing recommendation for observation in the setting of no symptoms, 11.6% of our patients still elected to proceed with implant removal. Exchange to smooth implants was the most popular surgical option at 64.4%.


Assuntos
Implante Mamário , Implantes de Mama , Neoplasias da Mama , Linfoma Anaplásico de Células Grandes , Humanos , Feminino , Implantes de Mama/efeitos adversos , Linfoma Anaplásico de Células Grandes/epidemiologia , Linfoma Anaplásico de Células Grandes/etiologia , Linfoma Anaplásico de Células Grandes/diagnóstico , Implante Mamário/efeitos adversos , Estudos Retrospectivos , Remoção de Dispositivo/efeitos adversos , Neoplasias da Mama/cirurgia , Neoplasias da Mama/complicações
7.
J Emerg Med ; 64(2): 246-250, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36746692

RESUMO

BACKGROUND: Since the development of the first U.S. Food and Drug Administration-approved vaccine for the prevention of serious disease and death associated with the SARS-CoV-2 virus, health care workers have been expected to comply with mandatory immunization requirements or face potential termination of employment and censure by their state medical boards. Although most accepted this mandate, there have been several who have felt this was an unnecessary intrusion and violation of their right to choose their own health care mitigation strategies, or an infringement on their autonomy and other civil liberties. Others have argued that being a health care professional places your duties above your own self-interests, so-called fiduciary duties. As a result of these duties, there is an expected obligation to do the best action to achieve the "most good" for society. A so-called "utilitarian argument." DISCUSSION: We explore arguments both for and against these mandatory vaccine requirements and conclude using duty- and consequence-based moral reasoning to weigh the merits of each. CONCLUSIONS: Although arguments for and against vaccine mandates are compelling, it is the opinion of the Ethics Committee of the American Academy of Emergency Medicine that vaccine mandates for health care workers are ethically just and appropriate, and the benefit to society far outweighs the minor inconvenience to an individual's personal liberties.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Humanos , SARS-CoV-2 , Pessoal de Saúde , Vacinação
8.
Violence Vict ; 38(4): 573-592, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37380342

RESUMO

There is a dearth of research on the relation of men's cumulative experiences of nonintimate victimization (polyvictimization) to their victimization in intimate relationships. This study examines the association between nonintimate polyvictimization (including being abused as a child, cyberbullied, stalked, physically assaulted, and experiencing property crime) and the severity of intimate partner violence victimization in men. The sample of 8,784 men in current married/common-law relationships was drawn from a random sample of the 2014 Canadian General Social Survey. About 3% of the men (an estimate of about 265,000 men in Canada) experienced the most severe forms of partner abuse, including the combination of emotional abuse and controlling behaviors, physical violence, and the resulted injuries. Among these severely abused men, about one-third were polyvictims. As expected, a nonintimate polyvictimization predicted the increased severity of male partner abuse victimization, controlling for sociodemographic variables. These findings highlight the importance of preventing nonintimate polyvictimization of men that can help reduce their partner violence victimization.


Assuntos
Vítimas de Crime , Violência por Parceiro Íntimo , Maus-Tratos Conjugais , Transtornos Relacionados ao Uso de Substâncias , Humanos , Masculino , Criança , Canadá , Violência , Homens , Vítimas de Crime/psicologia
9.
Arch Virol ; 167(12): 2633-2642, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36207555

RESUMO

The complete genomes of the new Erwinia amylovora bacteriophages Loshitsa2 and Micant are 43,092 bp and 43,028 bp long, respectively, encode 51 putative proteins, and have two tRNA genes. Comparative analysis with representatives of the class Caudoviricetes suggests that bacteriophages Loshitsa2 and Micant are related to LIMElight bacteriophage belonging to the family Autographiviridae and could be proposed to be members of a novel subfamily.


Assuntos
Bacteriófagos , Erwinia amylovora , Erwinia amylovora/genética , Bacteriófagos/genética , Doenças das Plantas
10.
J Hand Surg Am ; 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36336572

RESUMO

PURPOSE: Timothy syndrome (TS) is characterized by congenital long-QT arrhythmia and limb syndactyly. Patients who undergo syndactyly repair with undiagnosed TS may have their abnormal cardiac electrical activity unmasked during surgery. The purpose of this study was to detail the extremity phenotype seen in patients with TS, which may help hand surgeons in their preoperative assessment. METHODS: This was a retrospective review of all patients with TS seen at our institution from 1998 to 2022. Descriptive statistics regarding their demographics, medical and surgical histories, and syndactyly phenotypes were obtained. RESULTS: Seven patients (5 males and 2 females) with TS were seen at our institution for multidisciplinary evaluation (median age at presentation was 23 months). Six patients had finger syndactyly and 5 had toe syndactyly. One patient did not have any extremity syndactyly and was noted to have a specific TS mutation known to lack musculoskeletal abnormalities. All patients with finger syndactyly had border digit involvement, with 5 out of 6 patients displaying syndactyly of the middle-ring and ring-little finger web spaces. Toe syndactyly was more heterogeneous, with 1 patient lacking any lower extremity syndactyly and others having variable involvement of the second-third, third-fourth, and fourth-little toe web spaces. Complexity ranged from simple to complete. Four patients had intraoperative cardiac events leading to TS diagnoses after surgery. CONCLUSIONS: Bilateral border digit hand syndactyly, with or without bilateral toe syndactyly, should raise concerns for TS and prompt further investigation into potential cardiac disease to avoid perioperative cardiac morbidity and mortality. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

11.
Int J Mol Sci ; 23(19)2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36232640

RESUMO

The power of most of the enterobacterial O antigen types to provide robust protection against direct recognition of the cell surface by bacteriophage receptor-recognition proteins (RBP) has been recently recognized. The bacteriophages infecting O antigen producing strains of E. coli employ various strategies to tackle this nonspecific protection. T-even related phages, including RB49-like viruses, often have wide host ranges, being considered good candidates for use in phage therapy. However, the mechanisms by which these phages overcome the O antigen barrier remain unknown. We demonstrate here that RB49 and related phages Cognac49 and Whisky49 directly use certain types of O antigen as their primary receptors recognized by the virus long tail fibers (LTF) RBP gp38, so the O antigen becomes an attractant instead of an obstacle. Simultaneously to recognize multiple O antigen types, LTFs of each of these phages can bind to additional receptors, such as OmpA protein, enabling them to infect some rough strains of E. coli. We speculate that the mechanical force of the deployment of the short tail fibers (STF) triggered by the LTF binding to the O antigen or underneath of it, allows the receptor binding domains of STF to break through the O polysaccharide layer.


Assuntos
Bacteriófagos , Receptores de Bacteriófagos , Bacteriófagos/metabolismo , Escherichia coli/metabolismo , Especificidade de Hospedeiro , Antígenos O/metabolismo
12.
Int J Mol Sci ; 23(18)2022 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-36142829

RESUMO

Diseases caused by the Gram-positive bacterium Curtobacteriumflaccumfaciens pv. flaccumfaciens (Cff) inflict substantial economic losses in soybean cultivation. Use of specific bacterial viruses (bacteriophages) for treatment of seeds and plants to prevent the development of bacterial infections is a promising approach for bioprotection in agriculture. Phage control has been successfully tested for a number of staple crops. However, this approach has never been applied to treat bacterial diseases of legumes caused by Cff, and no specific bacteriophages have been known to date. This paper presents detailed characteristics of the first lytic bacteriophage infecting this pathogen. Phage Ayka, related to φ29-like (Salasmaviridae) viruses, but representing a new subfamily, was shown to control the development of bacterial wilt and tan spot in vitro and in greenhouse plants.


Assuntos
Actinomycetales , Infecções Bacterianas , Bacteriófagos , Fabaceae , Actinobacteria , Bactérias , Fabaceae/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Glycine max
13.
Appl Environ Microbiol ; 87(21): e0112421, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34406832

RESUMO

Tailed bacteriophages constitute the bulk of the intestinal viromes of vertebrate animals. However, the relationships between lytic and lysogenic lifestyles of phages in these ecosystems are not always clear and may vary between the species or even between the individuals. The human intestinal (fecal) viromes are dominated mostly by temperate phages, while in horse feces virulent phages are more prevalent. To our knowledge, all the previously reported isolates of horse fecal coliphages are virulent. Temperate coliphage Hf4s was isolated from horse feces, from the indigenous equine Escherichia coli 4s strain. It is a podovirus related to the Lederbergvirus genus (including the well-characterized Salmonella bacteriophage P22). Hf4s recognizes the host O antigen as its primary receptor and possesses a functional O antigen seroconversion cluster that renders the lysogens protected from superinfection by the same bacteriophage and also abolishes the adsorption of some indigenous equine virulent coliphages, such as DT57C, while other phages, such as G7C or phiKT, retain the ability to infect E. coli 4s (Hf4s) lysogens. IMPORTANCE The relationships between virulent and temperate bacteriophages and their impact on high-density symbiotic microbial ecosystems of animals are not always clear and may vary between species or even between individuals. The horse intestinal virome is dominated by virulent phages, and Hf4s is the first temperate equine intestinal coliphage characterized. It recognizes the host O antigen as its primary receptor and possesses a functional O antigen seroconversion cluster that renders the lysogens protected from superinfection by some indigenous equine virulent coliphages, such as DT57C, while other phages, such as G7C or phiKT, retain the ability to infect E. coli 4s (Hf4s) lysogens. These findings raise questions on the significance of bacteriophage-bacteriophage interactions within the ecology of microbial viruses in mammal intestinal ecosystems.


Assuntos
Colífagos , Cavalos/virologia , Podoviridae , Animais , Colífagos/genética , Escherichia coli/virologia , Genômica , Antígenos O , Podoviridae/genética , Superinfecção
14.
Nat Chem Biol ; 15(5): 529-539, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30992567

RESUMO

Understanding the mechanism of small molecules is a critical challenge in chemical biology and drug discovery. Medicinal chemistry is essential for elucidating drug mechanism, enabling variation of small molecule structure to gain structure-activity relationships (SARs). However, the development of complementary approaches that systematically vary target protein structure could provide equally informative SARs for investigating drug mechanism and protein function. Here we explore the ability of CRISPR-Cas9 mutagenesis to profile the interactions between lysine-specific histone demethylase 1 (LSD1) and chemical inhibitors in the context of acute myeloid leukemia (AML). Through this approach, termed CRISPR-suppressor scanning, we elucidate drug mechanism of action by showing that LSD1 enzyme activity is not required for AML survival and that LSD1 inhibitors instead function by disrupting interactions between LSD1 and the transcription factor GFI1B on chromatin. Our studies clarify how LSD1 inhibitors mechanistically operate in AML and demonstrate how CRISPR-suppressor scanning can uncover novel aspects of target biology.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Histona Desmetilases/genética , Histona Desmetilases/metabolismo , Leucemia Mieloide Aguda/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Histona Desmetilases/antagonistas & inibidores , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Modelos Moleculares , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
15.
Transfusion ; 61 Suppl 1: S313-S325, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34269450

RESUMO

BACKGROUND: The current global pandemic has created unprecedented challenges in the blood supply network. Given the recent shortages, there must be a civilian plan for massively bleeding patients when there are no blood products on the shelf. Recognizing that the time to death in bleeding patients is less than 2 h, timely resupply from unaffected locations is not possible. One solution is to transfuse emergency untested whole blood (EUWB), similar to the extensive military experience fine-tuned over the last 19 years. While this concept is anathema in current civilian transfusion practice, it seems prudent to have a vetted plan in place. METHODS AND MATERIALS: During the early stages of the 2020 global pandemic, a multidisciplinary and international group of clinicians with broad experience in transfusion medicine communicated routinely. The result is a planning document that provides both background information and a high-level guide on how to emergently deliver EUWB for patients who would otherwise die of hemorrhage. RESULTS AND CONCLUSIONS: Similar plans have been utilized in remote locations, both on the battlefield and in civilian practice. The proposed recommendations are designed to provide high-level guidance for experienced blood bankers, transfusion experts, clinicians, and health authorities. Like with all emergency preparedness, it is always better to have a well-thought-out and trained plan in place, rather than trying to develop a hasty plan in the midst of a disaster. We need to prevent the potential for empty shelves and bleeding patients dying for lack of blood.


Assuntos
Armazenamento de Sangue , Armazenamento de Sangue/métodos , Preservação de Sangue/métodos , Transfusão de Sangue/métodos , COVID-19/epidemiologia , Defesa Civil , Serviço Hospitalar de Emergência , Humanos , Pandemias
16.
Geophys Res Lett ; 48(24): e2021GL096410, 2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-35865360

RESUMO

Ensemble-based data assimilation of radar observations across inner-core regions of tropical cyclones (TCs) in tandem with satellite all-sky infrared (IR) radiances across the TC domain improves TC track and intensity forecasts. This study further investigates potential enhancements in TC track, intensity, and rainfall forecasts via assimilation of all-sky microwave (MW) radiances using Hurricane Harvey (2017) as an example. Assimilating Global Precipitation Measurement constellation all-sky MW radiances in addition to GOES-16 all-sky IR radiances reduces the forecast errors in the TC track, rapid intensification (RI), and peak intensity compared to assimilating all-sky IR radiances alone, including a 24-hr increase in forecast lead-time for RI. Assimilating all-sky MW radiances also improves Harvey's hydrometeor fields, which leads to improved forecasts of rainfall after Harvey's landfall. This study indicates that avenues exist for producing more accurate forecasts for TCs using available yet underutilized data, leading to better warnings of and preparedness for TC-associated hazards in the future.

17.
J Nat Prod ; 84(5): 1617-1625, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-33974416

RESUMO

Heliomycin (also known as resistomycin) is an antibiotic with a broad spectrum of biological activities. However, low aqueous solubility and poor knowledge of its chemical properties have limited the development of this natural product. Here, we present an original scheme for the introduction of aminoalkylamine residues at positions 3, 5, and 7 of heliomycin and, using this, have prepared a series of novel water-soluble derivatives. The addition of side chains to the heliomycin scaffold significantly improves their interaction with different DNA secondary structures. One derivative, 7-deoxy-7-(2-aminoethyl)amino-10-O-methylheliomycin (8e), demonstrated affinity, stabilization potential, and good selectivity toward i-motif-forming DNA sequences over the duplex and G-quadruplex. Heliomycin derivatives therefore represent promising molecular scaffolds for further development as DNA-i-motif interacting ligands and potential chemotherapeutic agents.


Assuntos
DNA/química , Compostos Policíclicos/química , Animais , Linhagem Celular , Quadruplex G , Humanos , Camundongos , Conformação de Ácido Nucleico , Solubilidade , Água
18.
Biochemistry (Mosc) ; 86(3): 257-261, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33838638

RESUMO

The imbalance of the renin-angiotensin system is currently considered as a potentially important factor of the pathogenesis of COVID-19 disease. It has been shown previously in the murine model, that the expression of angiotensin-converting enzyme 2 (ACE2) on the cell surface is downregulated in response to the infection by SARS-CoV virus or recombinant spike protein (S protein) alone. In the case of natural infection, circulation of the S protein in a soluble form is unlikely. However, in SARS-CoV-2, a large fraction of S protein trimers is pre-processed during virion morphogenesis due to the presence of furin protease cleavage site between the S1 and S2 subunits. Therefore, S protein transition into the fusion conformation may be accompanied by the separation of the S1 subunits carrying the receptor-binding domains from the membrane-bound S2 subunits. The fate of the S1 particles shed due to the spontaneous "firing" of some S protein trimers exposed on the virions and on the surface of infected cells has been never investigated. We hypothesize that the soluble S1 subunits of the SARS-CoV-2 S protein shed from the infected cells and from the virions in vivo may bind to the ACE2 and downregulate cell surface expression of this protein. The decrease in the ACE2 activity on the background of constant or increased ACE activity in the lungs may lead to the prevalence of angiotensin II effects over those of angiotensin (1-7), thus promoting thrombosis, inflammation, and pulmonary damage. This hypothesis also suggests the association between less pronounced shedding of the S1 particles reported for the S protein carrying the D614G mutation (vs. the wild type D614 protein), and lack of increased severity of the COVID-19 infection caused by the mutant (D614G) SARS-CoV-2 strain, despite its higher infectivity and higher in vivo viral load.


Assuntos
COVID-19/virologia , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Enzima de Conversão de Angiotensina 2/imunologia , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , COVID-19/metabolismo , COVID-19/patologia , Humanos , Camundongos , Modelos Moleculares , Mutação , Multimerização Proteica , Subunidades Proteicas , Sistema Renina-Angiotensina , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/genética
19.
Diabetes Spectr ; 34(2): 184-189, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34149259

RESUMO

BACKGROUND: Glycemic control is suboptimal in many individuals with type 2 diabetes. Although use of flash continuous glucose monitoring (CGM) has demonstrated A1C reductions in patients with type 2 diabetes treated with a multiple daily injection or insulin pump therapy regimen, the glycemic benefit of this technology in patients with type 2 diabetes using nonintensive treatment regimens has not been well studied. METHODS: This retrospective, observational study used the IBM Explorys database to assess changes in A1C after flash CGM prescription in a large population with suboptimally controlled type 2 diabetes treated with nonintensive therapy. Inclusion criteria were diagnosis of type 2 diabetes, age <65 years, treatment with basal insulin or noninsulin therapy, naive to any CGM, baseline A1C ≥8%, and a prescription for the FreeStyle Libre flash CGM system during the period between October 2017 and February 2020. Patients served as their own control subject. RESULTS: A total of 1,034 adults with type 2 diabetes (mean age 51.6 ± 9.2 years, 50.9% male, baseline A1C 10.1 ± 1.7%) were assessed. More patients received noninsulin treatments (n = 728) than basal insulin therapy (n = 306). We observed a significant reduction in A1C within the full cohort: from 10.1 ± 1.7 to 8.6 ± 1.8%; Δ -1.5 ± 2.2% (P <0.001). The largest reductions were seen in patients with a baseline A1C ≥12.0% (n = 181, A1C reduction -3.7%, P <0.001). Significant reductions were seen in both treatment groups (basal insulin -1.1%, noninsulin -1.6%, both P <0.001). CONCLUSION: Prescription of the flash CGM system was associated with significant reductions in A1C in patients with type 2 diabetes treated with basal insulin or noninsulin therapy. These findings provide evidence for expanding access to flash CGM within the broader population of people with type 2 diabetes.

20.
Diabetes Spectr ; 34(4): 407-418, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34866875

RESUMO

BACKGROUND: ACHIEVE Control, a prospective, open-label, randomized, pragmatic, real-life study in insulin-naive people with type 2 diabetes (A1C 8.0-11.0%), demonstrated superiority of insulin glargine 300 units/mL (Gla-300) versus first-generation standard-of-care basal insulin (SOC-BI; glargine 100 units/mL or insulin detemir) in achieving individualized A1C targets without documented symptomatic (glucose ≤3.9 mmol/L [≤70 mg/dL] or <3.0 mmol/L [<54 mg/dL]) or severe hypoglycemia (American Diabetes Association level 3) at 6 months. Noninsulin antihyperglycemic background therapies are commonly used; however, sulfonylureas may increase hypoglycemia risk. This post hoc analysis assessed outcomes according to background therapy. METHODS: Subgroup analyses were performed per concomitant use/nonuse of sulfonylureas, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, or sodium-glucose cotransporter 2 (SGLT2) inhibitors. End points (6 and 12 months) included A1C target attainment without documented symptomatic or severe hypoglycemia, A1C target attainment, and absence of documented symptomatic or severe hypoglycemia. RESULTS: Odds ratios (ORs) at 12 months mostly favored Gla-300 versus SOC-BI across subgroups except in analysis of SGLT2 inhibitors, in which ORs were similar. Among sulfonylurea users, ORs at 12 months strongly favored Gla-300 versus SOC-BI for all end points, particularly A1C target achievement without documented symptomatic hypoglycemia (glucose ≤3.9 mmol/L [≤70 mg/dL]; OR 1.25, 95% CI 1.02-1.53) or severe hypoglycemia and achievement of no documented symptomatic hypoglycemia (glucose <3.0 mmol/L [<54 mg/dL]; OR 1.25, 95% CI 1.02-1.52) or severe hypoglycemia. CONCLUSION: The results suggest that, in insulin-naive people with type 2 diabetes, Gla-300 is effective with a risk of hypoglycemia that is lower than or similar to that of SOC-BI regardless of background medication. Individuals receiving concomitant sulfonylureas were more likely to remain without symptomatic or severe hypoglycemia with Gla-300.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA