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Metal radicals have shown versatile reactivity in modern synthetic chemistry. However, the use of zinc radicals for molecular synthesis has been barely explored. Here, we show that a transient zinc radical can be formed through photoactivation of a zinc-zinc bonded compound, which is able to mediate the selective dimerization of alkenes and allenes. Treatment of dizinc compounds [L2Zn2] [L = CH3C(2,6-iPr2C6H3N)CHC(CH3)(NCH2CH2PR2); R = Ph (LPh) or iPr (LiPr)] with a diverse array of aromatic alkenes under UV irradiation (365 nm) facilely afforded the head-to-head coupling products, i.e., 1,4-dizinciobutanes in high yields. In addition, arylallenes could also be selectively dimerized by the dizinc compound to give 2,5-dizincyl-functionalized 1,5-hexadienes under the same conditions. Control reactions of [LPh2Zn2] in the presence of UV irradiation isolated a zinc phenyl complex and a trimeric zinc phosphide complex resulting from C-P bond cleavage at the tridentate ligand. Reactions of photoactivated dizinc compounds with organic spin traps, i.e., 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and 2,2'-bipyridine (2,2'-bpy), successfully isolated zinc radical trapping products [LZnOTEMP] and [LPhZn(2,2'-bpy)·-], respectively. The profile of alkene dimerization was elucidated by density functional theory calculations, which confirmed that a transient zinc radical [LZn·] was initially generated through homolytic Zn-Zn bond cleavage via photoactivation followed by single-electron transfer and radical dimerization. The unique selectivity of the current reaction was also studied computationally.
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Chirality-directed stem-cell-fate determination involves coordinated transcriptional and metabolomics programming that is only partially understood. Here, using high-throughput transcriptional-metabolic profiling and pipeline network analysis, the molecular architecture of chirality-guided mesenchymal stem cell lineage diversification is revealed. A total of 4769 genes and 250 metabolites are identified that are significantly biased by the biomimetic chiral extracellular microenvironment (ECM). Chirality-dependent energetic metabolism analysis has revealed that glycolysis is preferred during left-handed ECM-facilitated osteogenic differentiation, whereas oxidative phosphorylation is favored during right-handed ECM-promoted adipogenic differentiation. Stereo-specificity in the global metabolite landscape is also demonstrated, in which amino acids are enriched in left-handed ECM, while ether lipids and nucleotides are enriched in right-handed ECM. Furthermore, chirality-ordered transcriptomic-metabolic regulatory networks are established, which address the role of positive feedback loops between key genes and central metabolites in driving lineage diversification. The highly integrated genotype-phenotype picture of stereochemical selectivity would provide the fundamental principle of regenerative material design.
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Multiómica , Osteogénesis , Linaje de la Célula/genética , Diferenciación Celular/genética , MetabolómicaRESUMEN
Oral diseases concern almost every individual and are a serious health risk to the population. The restorative treatment of tooth and jaw defects is an important means to achieve oral function and support the appearance of the contour. Based on the principle of "learning from the nature", Deng Xuliang's group of Peking University School and Hospital of Stomatology has proposed a new concept of "microstructural biomimetic design and tissue adaptation of tooth/jaw materials" to address the worldwide problems of difficulty in treating dentine hypersensitivity, poor prognosis of restoration of tooth defects, and vertical bone augmentation of alveolar bone after tooth loss. The group has broken through the bottleneck of multi-stage biomimetic technology from the design of microscopic features to the enhancement of macroscopic effects, and invented key technologies such as crystalline/amorphous multi-level assembly, ion-transportation blocking, and multi-physical properties of the micro-environment reconstruction, etc. The group also pioneered the cationic-hydrogel desensitizer, digital stump and core integrated restorations, and developed new crown and bridge restorative materials, gradient functionalisation guided tissue regeneration membrane, and electrically responsive alveolar bone augmentation restorative membranes, etc. These products have established new clinical strategies for tooth/jaw defect repair and achieved innovative results. In conclusion, the research results of our group have strongly supported the theoretical improvement of stomatology, developed the technical system of oral hard tissue restoration, innovated the clinical treatment strategy, and led the progress of the stomatology industry.
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Biónica , Restauración Dental Permanente , Enfermedades de la Boca , HumanosRESUMEN
Here we designed enantiomeric lipid-mimetic glutamic acid derivatives (L/D-UG) and investigated their self-assembled chiral nanostructures and performance with the protein adsorption as well as the osteogenesis. It was found that L or D-UG can self-assemble into vesicle bilayers and two-dimensional (2D) nanocrystals via a kinetic and thermodynamic control, respectively. These chiral vesicles and 2D crystals showed differentiated adsorption of proteins by their curvature and chirality. Specifically, fibronectin constituted by L-amino acids adsorbed preferentially on L-UG 2D crystal in a semi-random pattern and L-2D nanocrystal show as the most effective structures to promote bone regeneration. The controlled vesicle and 2D crystal assemblies with different chirality and curvature helps to clarify their determine roles in protein adsorption and osteogenesis.
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This work reports the synthesis, characterization, and reactivity of the first example of a well-defined zinc α-diazoalkyl complex. Treatment of zinc(I)-zinc(I) bonded compound L2 Zn2 [L=CH3 C(2,6-i Pr2 C6 H3 N)CHC(CH3 )(NCH2 CH2 PPh2 )] or zinc(II) hydride LZnH with trimethylsilyldiazomethane affords zinc diazoalkyl complex LZnC(N2 )SiMe3 . This complex liberates N2 in the presence of a nickel catalyst to form an α-zincated phosphorus ylide by reacting with the pendant phosphine. It selectively undergoes formal [3+2] cycloaddition with CO2 or CO to form the corresponding product with a five-membered heterocyclic core. Notably, the use of CO in such a [3+2] cycloaddition reaction is unprecedented, reflecting a novel CO reaction mode.
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The nature of transition-metal-olefin bonding has been explained by the Dewar-Chatt-Duncanson model within a continuum of two extremes, namely, a π-complex and a metallacyclopropane. The textbook rule suggests that a low-spin late-transition-metal-ethylene complex more likely forms a π-complex rather than a metallacyclopropane. Herein, we report a low-spin late-transition-metal-bis-ethylene complex forming an unprecedented planar metalla-bis-cyclopropane structure with magnesium-based metalloligands. Treatment of LMgEt (L = [(DippNCMe)2CH]-, Dipp = 2,6-iPr2C6H3) with Ni(cod)2 (cod = 1,5-cyclooctadiene) formed the heterotrimetallic complex (LMg)2Ni(C2H4)2, which features a linear Mg-Ni-Mg linkage and a planar coordination geometry at the nickel center. Both structural features and computational studies strongly supported the Ni(C2H4)2 moiety as a nickelaspiropentane. The exposure of (LMg)2Ni(C2H4)2 to 1 bar H2 at room temperature produced a four-hydride-bridged complex (LMg)2Ni(µ-H)4. The profile of H2 activation was elucidated by density functional theory calculations, which indicated a novel Mg/Ni cooperative activation mechanism with no oxidation occurring at the metal center, differing from the prevailing mono-metal-based redox mechanism. Moreover, the heterotrimetallic complex (LMg)2Ni(C2H4)2 catalyzed the hydrogenation of a wide range of unsaturated substrates under mild conditions.
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This work provides a facile access to a series of triangular [Zn2M] (M = group 10 and 11 metals) clusters. Treatment of Zn-Zn-bonded compounds [LZn-ZnL] (L = CH3C(2,6-iPr2C6H3N)CHC(CH3)(NCH2CH2PR2); R = Ph, iPr) with zero-valent transition-metal reagents selectively afforded the corresponding triangular clusters [Zn2M], where M = Ni(0), Pd(0), and Pt(0). Notably, the isoelectronic triangular clusters [Zn2M]+, where M = Ag(I) and Cu(I), could also be obtained by reactions of [LZn-ZnL] with AgOTf and CuOTf, respectively. The [Zn2Ag]+ complex containing elusive Zn-Ag bonds was investigated by density functional theory analysis, showing a 3c-2e bonding feature in the metallic ring. The electrochemical behaviors of [Zn2M] complexes were examined and revealed the donation of electron density from the Zn-Zn σ-bond to the metal centers. Reaction of the [Zn2Ni] complex with isocyanide gave heterometallic species by coordination of isocyanide to the nickel center, keeping the trimetallic ring core structure intact. In contrast, the Zn-Zn bond was rapidly cleaved upon treatment of the [Zn2Ni] complex with dihydrogen or phenyl acetylene, generating the hydride- or acetylide-bridged heterotrimetallic complex.
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BACKGROUND: The repair of tissue defects has attracted considerable attention and remained a substantial challenge. Calcium silicate (CaSiO3, CS) bioceramics have attracted the interest of researchers due to their excellent biodegradability. Recent studies have demonstrated that nanoscale-modified bioactive materials with favorable biodegradability could promote bone tissue regeneration, providing an alternative approach for the repair of bone defects. However, the direct construction of biodegradable nanostructures in situ on CS bioceramics was still difficult. RESULTS: In this study, flower-like nanostructures were flexibly prepared in situ on biodegradable CS bioceramics via hydrothermal treatment. The flower-like nanostructure surfaces exhibited better hydrophilicity and more significantly stimulated cell adhesion, alkaline phosphatase (ALP) activity, and osteogenic differentiation. Furthermore, the CS bioceramics with flower-like nanostructures effectively promoted bone regeneration and were gradually replaced with newly formed bone due to the favorable biodegradability of these CS bioceramics. Importantly, we revealed an osteogenesis-related mechanism by which the FAK/p38 signaling pathway could be involved in the regulation of bone mesenchymal stem cell (BMSC) osteogenesis by the flower-like nanostructure surfaces. CONCLUSIONS: Flower-like nanostructure surfaces on CS bioceramics exerted a strong effect on promoting bone repair and regeneration, suggesting their excellent potential as bone implant candidates for improving bone regeneration.
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Nanoestructuras , Osteogénesis , Regeneración Ósea , Compuestos de Calcio , Transducción de Señal , SilicatosRESUMEN
This work reports a site-selective C-H borylation of pyridines at the ortho-position with pinacolborane enabled by an yttrocene catalyst. The reaction provides a new family of 2-pyridyl boronates with a broad substrate scope and high atom efficiency. The resultant boronates were able to undergo a variety of transformations, e.g., oxidation, Suzuki-Miyaura coupling, Chan-Lam amination and etherification. Catalytic intermediates, including ortho-C-H metalated and borylated complexes, were isolated from stoichiometric experiments and confirmed by single-crystal X-ray diffraction.
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The selective detection of salicylaldehyde skeleton is of great significance in phytochemistry and biological research but rarely reported. In this research, a simple and highly selective "turn-on" fluorescence sensor (CDB-Am) for salicylaldehyde skeleton was developed based on switch of photoinduced electron transfer (PET) and aggregation-induced emission (AIE). CDB-Am bearing amino-cyanodistyrene structure responded to salicylaldehyde in the range of 3.1 to 40 µM with a detection limit of 0.94 µM. The sensing process of formation of Schiff-base adduct CDB-SA was confirmed by 1H NMR, MS, and FT-IR spectra, revealing that a recovered AIE property accounted for the turn-on fluorescence response of CDB-Am and the intramolecular hydrogen bonding played a crucial role in the disruption of PET process. This sensing ability was successfully applied for both fluorescence qualitative test of salicylaldehyde skeleton on TLC analysis and quantitative detection of salicylaldehyde skeleton with good accuracy in the root bark of Periploca sepium, suggesting the extensive applications in phytochemistry and traditional Chinese herbal medicine. Furthermore, CDB-Am exhibited the first excellent fluorescence imaging ability in detecting salicylaldehyde skeleton in a living system. This work supplied a new strategy of preparing a novel "turn-on" fluorescence probe for detecting salicylaldehyde skeleton in complex environments and living bodies.
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Aldehídos/análisis , Colorantes Fluorescentes/análisis , Bases de Schiff/análisis , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Cromatografía en Capa Delgada , Fluorescencia , Humanos , Enlace de Hidrógeno , Radical Hidroxilo , Iminas/química , Límite de Detección , Células MCF-7 , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Medicina Tradicional China , Microscopía Fluorescente , Imagen Óptica , Corteza de la Planta , Raíces de Plantas , Espectrofotometría Ultravioleta , Sales de Tetrazolio/análisis , Tiazoles/análisisRESUMEN
Stimulated Raman scattering processes based on Raman crystals offer a simple and effective method to generate mid-IR lasers. However, currently available mid-IR Raman crystals are extremely scarce. Herein, a new type of mid-IR Raman crystal, BaGeO3, is reported. It crystallizes in the monoclinic space group C2/c with Ba2+ cations and [Ge3O9]6- rings as basic building units and features high transparency from 2.5 to 5.5 µm and a Raman response larger than that of diamond. The BaGeO3 crystal has 45 IR-active modes (22Au + 23Bu) and 42 Raman-active modes (20Ag + 22Bg). The wide mid-IR transparent window is attributed to the low phonon energy of the second-order IR-active Au â Bg mode. The strongest Raman band, located at 799 cm-1, arises from the symmetrically stretching vibration of the [Ge3O9]6- extra-ring Ge-O bonds. The findings provide new insights into the crystallographic and Raman spectroscopic characteristics of high-performance mid-IR Raman crystals.
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Aggregation-induced emission (AIE) provides a new strategy for preparing fluorescent sensors in aggregated state. In this paper, a series of crown ether-bridged bis-tetraphenylethylene compounds were synthesized in 78-84% yield by a simple procedure. The molecules exhibited excellent AIE properties in THF/H2O solutions and solid films. The investigation on sensing abilities for various biomolecules and metal ions suggested that Bis-TPE-1 possessed obvious response to folic acid, with fluorescence enhancement and blue shift of maximum emission wavelength from 380 nm to 365 nm. The detection limit for folic acid was 6.36 × 10-7 M, and the sensor's selectivity for folic acid was little interfered by the other species. The sensor mechanism was studied by FT-IR, 1H NMR, MS spectra and fluorescence Jobs' plot. The selective sensor for folic acid was applied in test paper and the analyses of real samples of mung bean and spinach. The superior bioimaging performance of Bis-TPE-1 for sensing folic acid was confirmed by the live cell imaging experiments, which indicated its good practical application potential for detecting folic acid.
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Éteres Corona/química , Colorantes Fluorescentes/química , Ácido Fólico/análisis , Estilbenos/química , Éteres Corona/síntesis química , Fluorescencia , Colorantes Fluorescentes/síntesis química , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Límite de Detección , Microscopía Confocal/métodos , Microscopía Fluorescente/métodos , Espectrometría de Fluorescencia/métodos , Spinacia oleracea/química , Estilbenos/síntesis química , Vigna/químicaRESUMEN
Divalent palladium-induced homocoupling of terminal zinc hydrides to zinc-zinc bonded complexes was achieved herein. Reactions of zinc hydrides [LZnH] (L = CH3C(2,6-iPr2C6H3N)CHC(CH3)(N(CH2)nCH2PPh2); 1a: n = 1; 1b: n = 2) with 0.5 equiv of allyl(cyclopentadienyl)palladium(II) afforded heterotrinuclear [Zn2Pd] complexes 3 containing direct Zn-Zn and Zn-Pd bonds, with concomitant elimination of propylene and cyclopentadiene. Complexes 3 were also accessed by the reactions of zinc hydrides 1 with allylpalladium(II) chloride with release of propylene and hydrogen chloride. Treatment of zinc hydrides 1 with 1 equiv of allyl(cyclopentadienyl)palladium(II) gave Zn-Pd bonded complex 5 by elimination of propylene, which can be transformed into heterotrinuclear complex 3 by further reaction with one additional molar equivalent of zinc hydrides. Heterobimetallic Zn-Pd complex 5b was found to be an effective catalyst in the hydrosilylation of benzaldehyde and its derivatives. Reaction of 5b with silane reagent Ph2SiH2 produced [Pd2Si2H2] complex 8 with cleavage of the Pd-Zn bond, which served as an initiating species in the catalytic reaction. Complexes 4b, 5, and 8 in this study were characterized by X-ray diffraction.
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Knowledge of the molecular-level structure of the Li2GeO3 melt is essential to understand its basic physicochemical properties. In this work, in situ Raman spectroscopy, factor group analysis, and density functional theory (DFT) calculations were applied to investigate the Li2GeO3 crystal Raman spectrum and its transformation during the crystal melting process. Finally, the Li2GeO3 melt structure was determined. The Li2GeO3 lattice phonons were fully analyzed by the factor group. The DFT calculations confirmed the analysis results and assigned all of the experimental Raman bands. There are two characteristic Raman bands in the experimental spectrum. The 495 cm-1 band (mid-frequency band) is attributed to the symmetric bending vibration of the Ge-O-Ge bond, and the 814 cm-1 band (high-frequency band) arises from the symmetric stretching vibration of the O-Ge-O bond. The mid-frequency band anomalously shifted to a higher frequency and the high-frequency band normally shifted to a lower frequency when the crystal melted. The DFT method was employed to investigate two possible Li2GeO3 melt structures, one consisting of the [GeO2Ø2] n (Ø = bridging oxygen) chain and the other consisting of the [Ge3O9] ring. The chain-type structure was demonstrated to provide a better description of the Li2GeO3 melt than the ring-type structure. The anomalous shift of the mid-frequency band is related to the shrinkage of the [GeO2Ø2] n chain. On the basis of the chain-type structure, the high viscosity of the Li2GeO3 melt and the growth phenomena of the Li2GeO3 crystal were explained.
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Aggregation-induced emission (AIE) molecules eliminate the aggregation-caused quenching (ACQ) phenomenon effectively and exhibit excellent properties of a fluorescent sensor in the aggregated state. In this paper, an allochroic fluorescent sensor based on AIE molecules with a diphenylacrylonitrile structure was prepared in high yield by a simple procedure. This molecule possessed good AIE properties and exhibited a sensitive sensor ability for aliphatic amines with an obvious color change from orange to blue-green. The detailed investigation on the detection of hydrazine suggested that the detection limit for hydrazine was 3.67 × 10-6 M, and the highly sensitive sensor for hydrazine was not influenced by other species. The sensor mechanism was confirmed by using 1H NMR and MS spectra. The sensor for hydrazine was successfully applied in a test paper, exhibiting good practical application potential for detecting hydrazine. The experiment of living cell imaging suggested that this sensor showed superior bioimaging performance and presented sensitive detection for hydrazine with an obvious color change from orange to blue-green.
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Colorantes Fluorescentes , Hidrazinas/análisis , Imagen Óptica , Humanos , Límite de Detección , Células MCF-7 , Microscopía ConfocalRESUMEN
MicroRNAs (miRNAs) have significant regulatory functions in the modulation of gene expression, making them essential biomarkers for the diagnosis and prognosis of diseases. Nevertheless, the identification of miRNA poses significant difficulty in terms of its low abundance, necessitating sensitive and reliable approaches. Herein, we develop a simple approach, termed Catalytic assembly of DNAzyme integrates with Primer Exchange Reaction (CDiPER), for reliable and sensitive miRNA detection through the target recognition-triggered DNAzyme assembly and primer exchange reaction (PER) strategy. In this method, target miRNA can precisely bind with a specifically designed hairpin probe (H probe) to induce the conformation changes of the H probe, releasing DNAzyme sections to activate the PER process for signal amplification and fluorescence signal production. The established method displays a high dynamic range of over 6 orders of magnitude and a low detection limit of 312 aM. The created method has a number of unique advantages, such as (i) a better sensitivity than existing systems using PER for signal amplification as a result of its integration with the target recognition-triggered DNAzyme assembly and (ii) streamlined operating procedures. Further, the technology was used to detect the expression of miRNA in collected clinical samples from diabetes mellitus patients, revealing that miRNA was decreased in patients and demonstrating the significant clinical promise of the method.
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The exciton-polaritons in a lead halide perovskite not only have great significance for macroscopic quantum effects but also possess vital potential for applications in ultralow-threshold polariton lasers, integrated photonics, slow-light devices, and quantum light sources. In this study, we have successfully demonstrated strong coupling with huge Rabi splitting of 553 meV between perovskite excitons and anapole modes in the perovskite metasurface at room temperature. This outcome is achieved by introducing anapole modes to suppress radiative losses, thereby confining light to the perovskite metasurface and subsequently hybridizing it with excitons in the same material. Our results indicate the formation of self-hybridized exciton-polaritons within the perovskite metasurface, which may pave the way towards achieving high coupling strengths that could potentially bring exciting phenomena to fruition, such as Bose-Einstein condensation as well as enabling applications such as efficient light-emitting diodes and lasers.
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Minimally invasive, efficient, and satisfactory treatment for irregular and lacunar bone defects is still a challenge. Alginate hydrogels serve as promising stem cell (SC) delivery systems for bone regeneration but are limited by low cellular viability, poor osteogenic differentiation, and insufficient mechanical support. Herein, we developed a BMSCs-laden mechanically reinforced bioactive sodium alginate composite hydrogel microspheres (BCHMs) system via a microfluidic method that possesses 1) a uniform size and good injectability to meet clinical bone defects with complex shapes, 2) high cellular viability maintenance and further osteogenic induction capacity, and 3) improved mechanical properties. As the main matrix, the sodium alginate hydrogel maintains the high viability of encapsulated BMSCs and efficient substance exchange. Enhanced mechanical properties and osteogenic differentiation of the BCHMs in vitro were observed with xonotlite (Ca6Si6O17(OH)2, CSH) nanowires incorporated. Furthermore, BCHMs with 12.5 % CSH were injected into rat femoral bone defects, and satisfactory in situ regeneration outcomes were observed. Overall, it is believed that BCHMs expand the application of polysaccharide science and provide a promising injectable bone substitute for minimally invasive bone repair.
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Hidrogeles , Osteogénesis , Ratas , Animales , Hidrogeles/farmacología , Microesferas , Regeneración Ósea , AlginatosRESUMEN
Aging skin, vulnerable to age-related defects, is poor in wound repair. Metabolic regulation in accumulated senescent cells (SnCs) with aging is essential for tissue homeostasis, and adequate ATP is important in cell activation for aged tissue repair. Strategies for ATP metabolism intervention hold prospects for therapeutic advances. Here, we found energy metabolic changes in aging skin from patients and mice. Our data show that metformin engineered EV (Met-EV) can enhance aged mouse skin repair, as well as ameliorate cellular senescence and restore cell dysfunctions. Notably, ATP metabolism was remodeled as reduced glycolysis and enhanced OXPHOS after Met-EV treatment. We show Met-EV rescue senescence-induced mitochondria dysfunctions and mitophagy suppressions, indicating the role of Met-EV in remodeling mitochondrial functions via mitophagy for adequate ATP production in aged tissue repair. Our results reveal the mechanism for SnCs rejuvenation by EV and suggest the disturbed energy metabolism, essential in age-related defects, to be a potential therapeutic target for facilitating aged tissue repair.
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Vesículas Extracelulares , Metformina , Humanos , Animales , Ratones , Anciano , Metabolismo Energético , Envejecimiento , Senescencia Celular , Adenosina TrifosfatoRESUMEN
OBJECTIVE: The benefit of postoperative adjuvant therapy for survival of oligodendrocyte glioma remains unclear. In this study, we compared the effect of chemoradiation therapy (CRT) and chemotherapy (CT) alone in patients who underwent resection. We aim to identify which adjuvant therapy provides more survival benefits. METHODS: We identified patients who underwent oligodendroglioma resection in the Surveillance, Epidemiology and End Results (SEER) database. A multivariate Cox regression analysis was used to evaluate the factors affecting survival rates. We used a propensity matching analysis to minimize selection bias in each group. We performed subgroup analyses based on patients' clinical characteristics. RESULTS: This study identified 1826 patients who received adjuvant CT (n = 503) or adjuvant CRT (n = 1323). On multivariate analysis, elderly, white and other race, and temporal lobe and parietal lobe tumor site were independent risk factors for improved overall survival (OS). After 1:1 propensity match, we included 501 patients who received CT and 501 with CRT. Patients in the CT group showed improved overall survival rate compared with those who received CRT (median OS: 146 months vs. 111 months). Subgroup analysis showed that improved overall survival in CT group was more significant in patients who were younger or older, male or female, white race, frontal lobe and parietal lobe tumor site, smaller tumor size (≤4 cm), and with gross total resection (GTR) (P < 0.05). CONCLUSIONS: In patients with resected oligodendroglioma, adjuvant CT is associated with better survival compared to adjuvant CRT. The benefit was more significant in patients who were younger and older, male and female, white race, frontal lobe and parietal lobe tumor site, smaller tumor size (≤4 cm), and with GTR.