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1.
J Am Chem Soc ; 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38968417

RESUMO

Chiral secondary alkyl amines with a vicinal quaternary stereocenter are undoubtedly important and ubiquitous subunits in natural products and pharmaceuticals. However, their asymmetric synthesis remains a formidable challenge. Herein, we merge the ring-opening 1,2-metallate shift with iridium-catalyzed enantioselective C(sp3)-H borylation of aziridines to deliver these frameworks with high enantioselectivities. We also demonstrated the synthetic application by downstream transformations, including the total synthesis of two Amaryllidaceae alkaloids, (-)-crinane and (+)-mesmebrane.

2.
J Am Chem Soc ; 146(20): 14357-14367, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38726589

RESUMO

Introducing dynamic behavior into periodic frameworks has borne fruit in the form of flexible porous crystals. The detailed molecular design of frameworks in order to control their collective dynamics is of particular interest, for example, to achieve stimulus-induced behavior. Herein, by varying the degree of rigidity of ditopic pillar linkers, two isostructural flexible metal-organic frameworks (MOFs) with common rigid supermolecular building bilayers were constructed. The subtle substitution of single (in bibenzyl-4,4'-dicarboxylic acid; H2BBDC) with double (in 4,4'-stilbenedicarboxylic acid; H2SDC) C-C bonds in pillared linkers led to markedly different flexible behavior of these two MOFs. Upon the removal of guest molecules, both frameworks clearly show reversible single-crystal-to-single-crystal transformations involving the cis-trans conformation change and a resulting swing of the corresponding pillar linkers, which gives rise to Flex-Cd-MOF-1a and Flex-Cd-MOF-2a, respectively. Strikingly, a more favorable gas-induced dynamic behavior in Flex-Cd-MOF-2a was verified in detail by stepwise C3H6/C3H8 sorption isotherms and the corresponding in situ powder X-ray diffraction experiments. These insights are strongly supported by molecular modeling studies on the sorption mechanism that explores the sorption landscape. Furthermore, a consistency between the macroscopic elasticity and microscopic flexibility of Flex-Cd-MOF-2 was observed. This work fuels a growing interest in developing MOFs with desired chemomechanical functions and presents detailed insights into the origins of flexible MOFs.

3.
J Org Chem ; 89(11): 7982-7990, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38805363

RESUMO

The synthesis of monofluorinated heterocyclic compounds by C-H activation combined with defluorination is useful. Studies on the reaction mechanism and selectivity have shown that these processes play a positive role in promoting the development of monofluorinated reactions. Density functional theory (DFT) calculations were performed to investigate the mechanism and selectivity of Ru(II)-catalyzed 2-arylbenzimidazole with trifluoromethyl diazo. DFT calculations showed that C-H activation occurs through a concerted metalation/deprotonation (CMD) mechanism. After that, deprotonation and defluorinative cyclization are assisted by acetate and trifluoroethanol (TFE). Further mechanistic insights through noncovalent interaction (NCI) analysis were also obtained to elucidate the origin of the selectivity in the defluorination process.

4.
Chem Asian J ; 19(12): e202400184, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38628038

RESUMO

We reported a chiral oxamide-phosphine ligand (COAP-Ph)-Pd-catalyzed asymmetric [3+2] cycloaddition reaction between vinyl cyclopropane compounds derived from 1,3-indanedione and 2-vinylcyclopropane-1,1-dicarboxylates with cyclic sulfonyl 1-azadienes. The corresponding reactions provided a series of enantiomerically active spiro cyclopentane-indandione and cyclopentane structures bearing three consecutive stereogenic centers in good yields with good diastereo- and enantioselectivity. The COAP-Pd complex serves not only to promote generation of chiral π-allyl-palladium intermediates and induce the asymmetry of the reaction, but also depress the background reaction.

5.
World J Gastrointest Oncol ; 16(4): 1213-1226, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38660630

RESUMO

BACKGROUND: Portal vein thrombosis (PVT), a complication of liver cirrhosis, is a major public health concern. PVT prediction is the most effective method for PVT diagnosis and treatment. AIM: To develop and validate a nomogram and network calculator based on clinical indicators to predict PVT in patients with cirrhosis. METHODS: Patients with cirrhosis hospitalized between January 2016 and December 2021 at the First Hospital of Lanzhou University were screened and 643 patients with cirrhosis who met the eligibility criteria were retrieved. Following a 1:1 propensity score matching 572 patients with cirrhosis were screened, and relevant clinical data were collected. PVT risk factors were identified using the least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression analysis. Variance inflation factors and correlation matrix plots were used to analyze multicollinearity among the variables. A nomogram was constructed to predict the probability of PVT based on independent risk factors for PVT, and its predictive performance was verified using a receiver operating characteristic curve (ROC), calibration curves, and decision curve analysis (DCA). Finally, a network calculator was constructed based on the nomograms. RESULTS: This study enrolled 286 cirrhosis patients with PVT and 286 without PVT. LASSO analysis revealed 13 variables as strongly associated with PVT occurrence. Multivariate logistic regression analysis revealed nine indicators as independent PVT risk factors, including etiology, ascites, gastroesophageal varices, platelet count, D-dimer, portal vein diameter, portal vein velocity, aspartate transaminase to neutrophil ratio index, and platelet-to-lymphocyte ratio. LASSO and correlation matrix plot results revealed no significant multicollinearity or correlation among the variables. A nomogram was constructed based on the screened independent risk factors. The nomogram had excellent predictive performance, with an area under the ROC curve of 0.821 and 0.829 in the training and testing groups, respectively. Calibration curves and DCA revealed its good clinical performance. Finally, the optimal cutoff value for the total nomogram score was 0.513. The sensitivity and specificity of the optimal cutoff values were 0.822 and 0.706, respectively. CONCLUSION: A nomogram for predicting PVT occurrence was successfully developed and validated, and a network calculator was constructed. This can enable clinicians to rapidly and easily identify high PVT risk groups.

6.
J Org Chem ; 89(7): 4904-4915, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38500413

RESUMO

The palladium-catalyzed highly regioselective asymmetric allylic alkylation of 3'-indolyl-3-oxindole derivatives with Morita-Baylis-Hillman (MBH) carbonates was developed to facilely construct chiral 3,3'-bisindole derivatives under mild reaction conditions. The regioselectivity (α/γ) of MBH carbonates was efficiently switched in the presence of chiral oxalamide phosphine or spiroketal-based diphosphine/Pd(0) complexes as a chiral catalyst. A series of multifunctional 3,3'-bisindole derivatives with all-carbon quaternary stereogenic centers were obtained in high yields with good to excellent enantio-, diastereo-, and regioselectivity. The present process is endowed with some salient features such as broad substrate scope, N-protecting group-free, excellent stereoselectivity, as well as adjustable regioselectivity.

7.
Adv Sci (Weinh) ; 11(23): e2401301, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38544484

RESUMO

The left atrial appendage (LAA) occluder is an important medical device for closing the LAA and preventing stroke. The device-related thrombus (DRT) prevents the implantation of the occluder in exerting the desired therapeutic effect, which is primarily caused by the delayed endothelialization of the occluder. Functional coatings are an effective strategy for accelerating the endothelialization of occluders. However, the occluder surface area is particularly large and structurally complex, and the device is subjected to a large shear friction in the sheath during implantation, which poses a significant challenge to the coating. Herein, a hydrogel coating by the in situ UV-triggered polymerization of double-network polyelectrolytes is reported. The findings reveal that the double network and electrostatic interactions between the networks resulted in excellent mechanical properties of the hydrogel coating. The sulfonate and Arg-Gly-Asp (RGD) groups in the coating promoted hemocompatibility and endothelial growth of the occluder, respectively. The coating significantly accelerated the endothelialization of the LAA occluder in a canine model is further demonstrated. This study has potential clinical benefits in reducing both the incidence of DRT and the postoperative anticoagulant course for LAA closure.


Assuntos
Hidrogéis , Polieletrólitos , Animais , Hidrogéis/química , Polieletrólitos/química , Cães , Apêndice Atrial/cirurgia , Raios Ultravioleta , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia
8.
Phytomedicine ; 128: 155377, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38503154

RESUMO

BACKGROUND: The existence of pancreatic cancer stem cells (PCSCs) results in limited survival benefits from current treatment options. There is a scarcity of effective agents for treating pancreatic cancer patients. Dehydroevodiamine (DeHE), a quinazoline alkaloid isolated from the traditional Chinese herb Evodiae fructus, exhibited potent inhibition of pancreatic ductal adenocarcinoma (PDAC) cell proliferation and tumor growth both in vitro and in vivo. METHODS: The cytotoxic effect of DeHE on PDAC cells was assessed using CCK-8 and colony formation assays. The antitumor efficacy of DeHE were appraised in human PANC-1 xenograft mouse model. Sphere formation assay and flow cytometry were employed to quantify the tumor stemness. RNA-Seq analysis, drug affinity responsive target stability assay (DARTS), and RNA interference transfection were conducted to elucidate potential signaling pathways. Western blotting and immunohistochemistry were utilized to assess protein expression levels. RESULTS: DeHE effectively inhibited PDAC cell proliferation and tumor growth in vitro and in vivo, and exhibited a better safety profile compared to the clinical drug gemcitabine (GEM). DeHE inhibited PCSCs, as evidenced by its suppression of self-renewal capabilities of PCSCs, reduced the proportion of ALDH+ cells and downregulated stemness-associated proteins (Nanog, Sox-2, and Oct-4) both in vitro and in vivo. Furthermore, there is potential involvement of DDIT3 and its downstream DDIT3/TRIB3/AKT/mTOR pathway in the suppression of stemness characteristics within DeHE-treated PDAC cells. Additionally, results from the DARTS assay indicated that DeHE interacts with DDIT3, safeguarding it against degradation mediated by pronase. Notably, the inhibitory capabilities of DeHE on PDAC cell proliferation and tumor stemness were partially restored by siDDIT3 or the AKT activator SC-79. CONCLUSION: In summary, our study has identified DeHE, a novel antitumor natural product, as an activator of DDIT3 with the ability to suppress the AKT/mTOR pathway. This pathway is intricately linked to tumor cell proliferation and stemness characteristics in PDAC. These findings suggest that DeHE holds potential as a promising candidate for the development of innovative anticancer therapeutics.


Assuntos
Proliferação de Células , Células-Tronco Neoplásicas , Neoplasias Pancreáticas , Animais , Humanos , Camundongos , Antineoplásicos Fitogênicos/farmacologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Evodia/química , Gencitabina , Camundongos Endogâmicos BALB C , Camundongos Nus , Células-Tronco Neoplásicas/efeitos dos fármacos , Neoplasias Pancreáticas/tratamento farmacológico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quinazolinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Fator de Transcrição CHOP/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Nat Commun ; 15(1): 1462, 2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38368405

RESUMO

Ethylene/α-olefin copolymers are produced in huge scale and widely used, but their after-use disposal has caused plastic pollution problems. Their chemical inertness made chemical re/upcycling difficult. Ideally, PE materials should be made de novo to have a circular closed-loop lifecycle. However, synthesis of circular ethylene/α-olefin copolymers, including high-volume, linear low-density PE as well as high-value olefin elastomers and block copolymers, presents a particular challenge due to difficulties in introducing branches while simultaneously installing chemical recyclability and directly using industrial ethylene and α-olefin feedstocks. Here we show that coupling of industrial coordination copolymerization of ethylene and α-olefins with a designed functionalized chain-transfer agent, followed by modular assembly of the resulting AB telechelic polyolefin building blocks by polycondensation, affords a series of ester-linked PE-based copolymers. These new materials not only retain thermomechanical properties of PE-based materials but also exhibit full chemical circularity via simple transesterification and markedly enhanced adhesion to polar surfaces.

10.
Invest Ophthalmol Vis Sci ; 65(2): 6, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38306106

RESUMO

Purpose: To explore the central and peripheral retinal and choroidal changes in retinal vein occlusion (RVO) and fellow eyes using ultra-widefield swept-source optical coherence tomography angiography (UWF-SS-OCTA). Methods: Fifteen ischemic central RVO (CRVO), 15 branch RVO (BRVO), and 15 age-matched healthy controls were prospectively recruited. Retinal and choroidal parameters, including retinal vessel flow density (VFD) and vessel linear density (VLD), choroidal vascularity volume (CVV), choroidal vascularity index (CVI), and VFD in the large and medium choroidal vessels (LMCV-VFD), were measured in the central and peripheral regions of the 24 × 20-mm UWF-SS-OCTA images. Results: Ischemic CRVO and BRVO eyes showed increased foveal avascular zone area, perimeter, and acircularity index (AI) compared to their fellow eyes and healthy control eyes, and RVO fellow eyes also had larger AI values than controls (P < 0.05). For ischemic CRVO and BRVO eyes versus control eyes, VFD, VLD, CVV, CVI, and LMCV-VFD decreased, but retinal thickness and volume in the superficial capillary plexus, deep capillary plexus, and whole retina increased (P < 0.05). Moreover, RVO fellow eyes also showed significantly decreased retinal VFD, LMCV-VFD, and CVI, as well as increased retinal thickness and volume, compared with control eyes (P < 0.05). Alterations were not consistent throughout the retina, as they involved only the peripheral or central regions in some cases. Conclusions: The affected and unaffected fellow eyes of RVO patients both demonstrated central and/or peripheral structural and vascular alterations in the retina and choroid. Because UWF-SS-OCTA enables visualization and evaluation of the vasculature outside the posterior pole, it presents a promising approach to more fully characterize vascular alterations in RVO.


Assuntos
Oclusão da Veia Retiniana , Humanos , Oclusão da Veia Retiniana/diagnóstico , Tomografia de Coerência Óptica/métodos , Angiofluoresceinografia/métodos , Estudos Retrospectivos , Vasos Retinianos/diagnóstico por imagem
11.
Adv Mater ; 36(15): e2310216, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38237136

RESUMO

The sprayable hydrogel coatings that can establish robust adhesion onto diverse materials and devices hold enormous potential; however, a significant challenge persists due to monomer hydration, which impedes even coverage during spraying and induces inadequate adhesion post-gelation. Herein, a polycation-reinforced (PCR) surface bridging strategy is presented to achieve tough and sprayable hydrogel coatings onto diverse materials. The polycations offer superior wettability and instant electrostatic interactions with plasma-treated substrates, facilitating an effective spraying application. This PCR-based hydrogel coatings demonstrate tough adhesion performance to inert PTFE and silicone, including remarkable shear strength (161 ± 49 kPa for PTFE), interfacial toughness (198 ± 27 J m-2 for PTFE), and notable tolerance to cyclic tension (10 000 cycles, 200% strain, silicone). Meanwhile, this method can be applied to various hydrogel formulations, offering diverse functionalities, including underwater adhesion, lubrication, and drug delivery. Furthermore, the PCR concept enables the conformal construction of durable hydrogel coatings onto sophisticated medical devices like cardiovascular stents. Given its simplicity and adaptability, this approach paves an avenue for incorporating hydrogels onto solid surfaces and potentially promotes untapped applications.


Assuntos
Hidrogéis , Polieletrólitos , Silicones , Politetrafluoretileno , Reação em Cadeia da Polimerase
13.
Microbiol Res ; 279: 127548, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38016378

RESUMO

The maintenance of oral health is of utmost importance for an individual's holistic well-being and standard of living. Within the oral cavity, symbiotic microorganisms actively safeguard themselves against potential foreign diseases by upholding a multifaceted equilibrium. Nevertheless, the occurrence of an imbalance can give rise to a range of oral infectious ailments, such as dental caries, periodontitis, and oral candidiasis. Presently, clinical interventions encompass the physical elimination of pathogens and the administration of antibiotics to regulate bacterial and fungal infections. Given the limitations of various antimicrobial drugs frequently employed in dental practice, the rising incidence of oral inflammation, and the escalating bacterial resistance to antibiotics, it is imperative to explore alternative remedies that are dependable, efficacious, and affordable for the prevention and management of oral infectious ailments. There is an increasing interest in the creation of novel antimicrobial agents derived from natural sources, which possess attributes such as safety, cost-effectiveness, and minimal adverse effects. This review provides a comprehensive overview of the impact of natural products on the development and progression of oral infectious diseases. Specifically, these products exert their influences by mitigating dental biofilm formation, impeding the proliferation of oral pathogens, and hindering bacterial adhesion to tooth surfaces. The review also encompasses an examination of the various classes of natural products, their antimicrobial mechanisms, and their potential therapeutic applications and limitations in the context of oral infections. The insights garnered from this review can support the promising application of natural products as viable therapeutic options for managing oral infectious diseases.


Assuntos
Anti-Infecciosos , Produtos Biológicos , Doenças Transmissíveis , Cárie Dentária , Humanos , Produtos Biológicos/farmacologia , Cárie Dentária/tratamento farmacológico , Cárie Dentária/prevenção & controle , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Antibacterianos/farmacologia , Doenças Transmissíveis/tratamento farmacológico
14.
Food Chem Toxicol ; 184: 114415, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38141941

RESUMO

Chalcones from licorice and its related plants have many pharmacological effects. However, the effects of chalcones on the activity of human and rat 11ß-hydroxysteroid dehydrogenase 2 (11ß-HSD2), and associated side effects remain unclear. The inhibition of 11 chalcones on human and rat 11ß-HSD2 were evaluated in microsomes and a 3D-quantitative structure-activity relationship (3D-QSAR) was analyzed. Screening revealed that bavachalcone, echinatin, isobavachalcone, isobavachromene, isoliquiritigenin, licochalcone A, and licochalcone B significantly inhibited human 11ß-HSD2 with IC50 values ranging from 15.62 (licochalcone A) to 38.33 (echinatin) µM. Screening showed that the above chemicals and 4-hydroxychalcone significantly inhibited rat 11ß-HSD2 with IC50 values ranging from 6.82 (isobavachalcone) to 72.26 (4-hydroxychalcone) µM. These chalcones acted as noncompetitive/mixed inhibitors for both enzymes. Comparative analysis revealed that inhibition of 11ß-HSD2 depended on the species. Most chemicals bind to the NAD+ binding site or both the NAD+ and substrate binding sites. Bivariate correlation analysis showed that lipophilicity and molecular weight determine inhibitory strength. Through our 3D-QSAR models, we identified that the hydrophobic region, hydrophobic aliphatic groups, and hydrogen bond acceptors are pivotal factors in inhibiting 11ß-HSD2. In conclusion, many chalcones inhibit human and rat 11ß-HSD2, possibly causing side effects and there is structure-dependent and species-dependent inhibition on 11ß-HSD2.


Assuntos
Chalconas , Ratos , Humanos , Animais , Chalconas/farmacologia , 11-beta-Hidroxiesteroide Desidrogenases/metabolismo , Relação Quantitativa Estrutura-Atividade , 11-beta-Hidroxiesteroide Desidrogenase Tipo 2/metabolismo , NAD/metabolismo
15.
World J Gastroenterol ; 29(39): 5435-5451, 2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37900996

RESUMO

Small extracellular vesicles (exosomes) are important components of the tumor microenvironment. They are small membrane-bound vesicles derived from almost all cell types and play an important role in intercellular communication. Exosomes transmit biological molecules obtained from parent cells, such as proteins, lipids, and nucleic acids, and are involved in cancer development. MicroRNAs (miRNAs), the most abundant contents in exosomes, are selectively packaged into exosomes to carry out their biological functions. Recent studies have revealed that exosome-delivered miRNAs play crucial roles in the tumorigenesis, progression, and drug resistance of hepatocellular carcinoma (HCC). In addition, exosomes have great industrial prospects in the diagnosis, treatment, and prognosis of patients with HCC. This review summarized the composition and function of exosomal miRNAs of different cell origins in HCC and highlighted the association between exosomal miRNAs from stromal cells and immune cells in the tumor microenvironment and the progression of HCC. Finally, we described the potential applicability of exosomal miRNAs derived from mesenchymal stem cells in the treatment of HCC.


Assuntos
Carcinoma Hepatocelular , Exossomos , Vesículas Extracelulares , Neoplasias Hepáticas , MicroRNAs , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , Carcinoma Hepatocelular/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , Neoplasias Hepáticas/metabolismo , Exossomos/genética , Exossomos/metabolismo , Vesículas Extracelulares/metabolismo , Microambiente Tumoral/genética
16.
Ann Med ; 55(2): 2262502, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37796532

RESUMO

PURPOSE: To explore the incidence, risk factors, management and prognosis of systemic complications after ophthalmic surgeries. METHODS: A retrospective review of hospitalized patients undergoing ophthalmic surgeries between 2012 and 2022 at Peking Union Medical College Hospital was performed to summarize and analyse the postoperative systemic complications. Multivariate logistic and linear regression analyses were conducted to clarify the risk factors of postoperative systemic complications and factors associated with the severity of adverse events. RESULTS: A total of 34,841 patients underwent inpatient ophthalmic surgery, among which 162 systemic complications occurred in 150 patients during postoperative hospitalization. The overall incidence rate was 0.4%, with cardiovascular events (48.1%), digestive events (13.6%) and fever (12.3%) being the leading causes. About 17.3% of the cases had conditions improved after observation, 19.1% after symptomatic treatment, 54.9% had consultation with specific intervention and 8.6% were transferred to the corresponding departments for specialized treatment. For the prognosis, 93.8% had condition improved, 5.6% chose voluntary discharge without improvement, and one patient died of respiratory failure caused by postoperative pulmonary infection. The worse ADL (activities of daily living) grading, indication of primary intraocular lymphoma or intraocular tumour, surgery of simple pars plana vitrectomy (PPV), PPV with silicone oil tamponade, PPV with gas tamponade, general anaesthesia, history of diabetes mellitus (DM), chronic heart failure and digestive system disease were the risk factors positively correlated with postoperative systemic complications (p < .05). The worse ADL grading, history of DM and respiratory system disease were also positively correlated with the severity of the adverse events (p < .05). CONCLUSIONS: The incidence of postoperative systemic complications was low among patients undergoing ophthalmic surgery, most were mild and could be relieved after observation, symptomatic or specialist consultation. Patients with worse ADL and history of DM should be paid extra attention.


Assuntos
Descolamento Retiniano , Humanos , Descolamento Retiniano/etiologia , Descolamento Retiniano/cirurgia , Estudos Retrospectivos , Incidência , Atividades Cotidianas , Fatores de Risco , Prognóstico , Centros de Atenção Terciária , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Encaminhamento e Consulta
17.
J Org Chem ; 88(16): 11867-11873, 2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37527492

RESUMO

A palladium-catalyzed regioselective and asymmetric allylic alkylation of azlactones with MBH carbonates has been developed with chiral oxalamide-phosphine ligands. The corresponding reaction afforded a range of optically active γ-arylidenyl glutamic acid derivatives bearing an α-chiral quaternary stereocenter in good yields with excellent linear regio- and high enantioselectivity. This protocol furnishes an alternative approach for the construction of enantio-enriched unnatural α-amino acid derivatives.

18.
ACS Omega ; 8(25): 23098-23111, 2023 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-37396220

RESUMO

In order to understand the influence of underground coal fires on coal fractures and pores, mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) are combined to study the development of coal pore and fracture under high-temperature treatment and calculate the fractal dimension to analyze the relationship between the development of coal pore and fracture and the fractal dimension. The results show that the volume of pores and fractures of the coal sample (C200) treated at 200 °C (0.1715 mL/g) is greater than that of the coal sample (C400) treated at 400 °C (0.1209 mL/g), and both are greater than the original coal sample (RC) (0.1135 mL/g). The volume increase is mainly due to mesopores and macropores, and the proportions of mesopores and macropores in C200 were 70.15 and 59.97% in C400. The MIP fractal dimension shows a decreasing trend with the increase of temperature, and the connectivity of coal samples improved with the increase of temperature. The changes in volume and three-dimensional fractal dimension of C200 and C400 showed the opposite trend and are related to the different stress of coal matrix at different temperatures. The experimental SEM images confirm that the connectivity of coal fractures and pores improves with the increase of temperature. Based on the SEM experiment, the larger the fractal dimension, the more complex the surface is. The SEM surface fractal dimensions indicate that the surface fractal dimension of C200 is the smallest and that of C400 is the largest, which is consistent with the observations made by SEM. The combination of the two fractal dimensions is used to characterize the self-similarity of coal using the fractal dimension difference. When the temperature increased to 200 °C, the unordered expansion of the coal sample resulted in the largest fractal dimension difference and the lowest self-similarity. When heated to 400 °C, the fractal dimension difference of the coal sample is the smallest, and the microstructure of coal shows a regular groove-like development.

19.
J Thorac Dis ; 15(5): 2859-2872, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37324081

RESUMO

Background: Effective anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) drugs are not only the next defense after vaccines but also the key part of establishing a multi-tiered coronavirus disease 2019 (COVID-19) prevention and control system. Previous studies had indicated that Lianhua Qingwen (LHQW) capsules could be an efficacious Chinese patent drug for treating mild to moderate COVID-19. However, pharmacoeconomic evaluations are lacking, and few trials have been conducted in other countries or regions to evaluate the efficacy and safety of LHQW treatment. So, this study aims to explore the clinical efficacy, safety, and economy of LHQW for treating adult patients with mild to moderate COVID-19. Methods: This is a randomized, double-blind, placebo-controlled, international multicenter clinical trial protocol. A total of 860 eligible subjects are randomized at a 1:1 ratio into the LHQW or placebo group to receive two-week treatment and follow-up visits on days 0, 3, 7, 10, and 14. Clinical symptoms, patient compliance, adverse effects, cost scale, and other indicators are recorded. The primary outcomes will be the measured median time to sustained improvement or resolution of the nine major symptoms during the 14-day observation period. Secondary outcomes regarding clinical efficacy will be evaluated in detail on the basis of clinical symptoms (especially body temperature, gastrointestinal symptoms, smell loss, and taste loss), viral nucleic acid, imaging (CT/chest X-ray), the incidence of severe/critical illness, mortality, and inflammatory factors. Moreover, we will assess health care cost, health utility, and incremental cost-effectiveness ratio (ICER) for economic evaluation. Discussion: This is the first international multicenter randomized controlled trial (RCT) of Chinese patent medicine for the treatment of early COVID-19 in accordance with WHO guidelines on COVID-19 management. This study will help clarify the potential efficacy and cost-effectiveness of LHQW in the treatment of mild to moderate COVID-19, facilitating decision-making by healthcare workers. Registration: This study is registered at the Chinese Clinical Trial Registry, with registration number: ChiCTR2200056727 (date of first registration: 11/02/2022).

20.
Phytother Res ; 37(9): 4282-4297, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37282760

RESUMO

Transient receptor potential vanilloid 4 (TRPV4) plays a role in regulating pulmonary fibrosis (PF). While several TRPV4 antagonists including magnolol (MAG), have been discovered, the mechanism of action is not fully understood. This study aimed to investigate the effect of MAG on alleviating fibrosis in chronic obstructive pulmonary disease (COPD) based on TRPV4, and to further analyze its mechanism of action on TRPV4. COPD was induced using cigarette smoke and LPS. The therapeutic effect of MAG on COPD-induced fibrosis was evaluated. TRPV4 was identified as the main target protein of MAG using target protein capture with MAG probe and drug affinity response target stability assay. The binding sites of MAG at TRPV4 were analyzed using molecular docking and small molecule interaction with TRPV4-ankyrin repeat domain (ARD). The effects of MAG on TRPV4 membrane distribution and channel activity were analyzed by co-immunoprecipitation, fluorescence co-localization, and living cell assay of calcium levels. By targeting TRPV4-ARD, MAG disrupted the binding between phosphatidylinositol 3 kinase γ and TRPV4, leading to hampered membrane distribution on fibroblasts. Additionally, MAG competitively impaired ATP binding to TRPV4-ARD, inhibiting TRPV4 channel opening activity. MAG effectively blocked the fibrotic process caused by mechanical or inflammatory signals, thus alleviating PF in COPD. Targeting TRPV4-ARD presents a novel treatment strategy for PF in COPD.


Assuntos
Antineoplásicos , Doença Pulmonar Obstrutiva Crônica , Fibrose Pulmonar , Humanos , Repetição de Anquirina , Fibrose Pulmonar/metabolismo , Canais de Cátion TRPV/metabolismo , Simulação de Acoplamento Molecular , Fibrose
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