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1.
Front Oncol ; 14: 1403822, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39099698

RESUMEN

Objective: The purpose of this study is to investigate potential associations between osteopenia, osteosarcopenia, and postoperative outcomes in patients with hepatobiliary-pancreatic cancer (HBPC). Methods: Three online databases, including Embase, PubMed, and the Cochrane Library, were thoroughly searched for literature describing the relationship between osteopenia, osteosarcopenia, and outcomes of surgical treatment of HBPC patients from the start of each database to September 29, 2023. The Newcastle-Ottawa Scale was used to rate the quality of the studies. Results: This analysis included a total of 16 articles with a combined patient cohort of 2,599 individuals. The results demonstrated that HBPC patients with osteopenia had significantly inferior OS (HR: 2.27, 95% CI: 1.70-3.03, p < 0.001) and RFS (HR: 1.96, 95% CI: 1.42-2.71, p < 0.001) compared to those without osteopenia. Subgroup analysis demonstrated that these findings were consistent across univariate and multivariate analyses, as well as hepatocellular carcinoma, biliary tract cancer, and pancreatic cancer. The risk of postoperative major complications was significantly higher in patients with osteopenia compared to those without osteopenia (OR: 1.66, 95% CI: 1.19-2.33, p < 0.001). Besides, we also found that the presence of osteosarcopenia in HBPC patients was significantly related to poorer OS (HR: 3.31, 95% CI: 2.00-5.48, p < 0.001) and PFS (HR: 2.50, 95% CI: 1.62-3.84, p < 0.001) in comparison to those without osteosarcopenia. Conclusion: Preoperative osteopenia and osteosarcopenia can predict poorer OS and RFS with HBPC after surgery.

3.
Org Lett ; 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39109801

RESUMEN

A visible-light-induced intramolecular diradical-mediated hydrogen atom transfer (DHAT) of primary, secondary, and tertiary C(sp3)-H bonds and subsequent cyclization is described. This transformation is enabled by triplet energy transfer upon Lewis acid coordination to alkyl-substituted arylvinylpyridines and gives access to a variety of benzocyclobutenes (>40 examples, 32-96% yield). Notably, tri- and tetrasubstituted olefins with tertiary C(sp3)-H bonds effectively delivered sterically hindered products with adjacent all-carbon quaternary centers. Mechanistic evidence and density functional theory (DFT) calculations suggest that Lewis acid coordination was crucial for the success by modulating the reactivity of the diradical intermediates to unlock a challenging carbon-to-carbon DHAT and subsequent cyclization with a rather low barrier, which allows the functionalization of benzylic C(sp3)-H bonds to construct otherwise inaccessible benzocyclobutenes.

4.
Nat Chem Biol ; 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39090313

RESUMEN

Cytoplasmic dynein is essential for intracellular transport. Despite extensive in vitro characterizations, how the dynein motors transport vesicles by processive steps in live cells remains unclear. To dissect the molecular mechanisms of dynein, we develop optical probes that enable long-term single-particle tracking in live cells with high spatiotemporal resolution. We find that the number of active dynein motors transporting cargo switches stochastically between one and five dynein motors during long-range transport in neuronal axons. Our very bright optical probes allow the observation of individual molecular steps. Strikingly, these measurements reveal that the dwell times between steps are controlled by two temperature-dependent rate constants in which two ATP molecules are hydrolyzed sequentially during each dynein step. Thus, our observations uncover a previously unknown chemomechanical cycle of dynein-mediated cargo transport in living cells.

5.
RSC Adv ; 14(34): 25008-25018, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39131503

RESUMEN

Here, we report improved syntheses, detailed characterizations and reactions of a series of acene-2,3-dicarbaldehydes including tetracene-2,3-dicarbaldehyde. DFT calculations corroborate and complement the experimental results. Tetracene-2,3-dicarbaldehyde and the benchmark organic semiconductor pentacene have isoelectronic π-systems and similar HOMO-LUMO gaps. Tetracene-2,3-dicarbaldehyde is soluble in a host of organic solvents (e.g., DMF, toluene, THF, chloroform, dichloromethane) and shows excellent photooxidative resistance in solution phases exposed to light and air. Further, it is readily sublimed from the solid-state without decomposition, and can be functionalized using different chemistries. We have demonstrated the utility of acene-2,3-dicarbaldehydes as reactants in the syntheses of novel α,α'-diaryl-2,3-acenedimethanols and acenotropones via Grignard reactions and double-aldol condensation reactions, respectively. The acenotropones were further reacted with concentrated H2SO4 to generate hydroxyacenotropylium ions that exhibit long wavelength absorption in the visible and near-IR regions. The optical gap measured for hydroxyanthracenotropylium ion is 1.3 eV. The results gained here implicate acene-2,3-dicarbaldehydes as potential high-value organic semiconductors and as precursors to a host of interesting molecules and materials.

6.
Asian J Surg ; 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39112334
7.
Proc Natl Acad Sci U S A ; 121(33): e2406775121, 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39116134

RESUMEN

Biofilm-protected pathogenic Staphylococcus aureus causes chronic infections that are difficult to treat. An essential building block of these biofilms are functional amyloid fibrils that assemble from phenol-soluble modulins (PSMs). PSMα1 cross-seeds other PSMs into cross-ß amyloid folds and is therefore a key element in initiating biofilm formation. However, the paucity of high-resolution structures hinders efforts to prevent amyloid assembly and biofilm formation. Here, we present a 3.5 Å resolution density map of the major PSMα1 fibril form revealing a left-handed cross-ß fibril composed of two C2-symmetric U-shaped protofilaments whose subunits are unusually tilted out-of-plane. Monomeric α-helical PSMα1 is extremely cytotoxic to cells, despite the moderate toxicity of the cross-ß fibril. We suggest mechanistic insights into the PSM functional amyloid formation and conformation transformation on the path from monomer-to-fibril formation. Details of PSMα1 assembly and fibril polymorphism suggest how S. aureus utilizes functional amyloids to form biofilms and establish a framework for developing therapeutics against infection and antimicrobial resistance.


Asunto(s)
Amiloide , Biopelículas , Staphylococcus aureus , Staphylococcus aureus/metabolismo , Staphylococcus aureus/fisiología , Biopelículas/crecimiento & desarrollo , Amiloide/metabolismo , Amiloide/química , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/química , Conformación Proteica , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Modelos Moleculares
8.
Nat Commun ; 15(1): 6843, 2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-39122671

RESUMEN

Despite the potential of small molecules and recombinant proteins to enhance the efficiency of homology-directed repair (HDR), single-stranded DNA (ssDNA) donors, as currently designed and chemically modified, remain suboptimal for precise gene editing. Here, we screen the biased ssDNA binding sequences of DNA repair-related proteins and engineer RAD51-preferred sequences into HDR-boosting modules for ssDNA donors. Donors with these modules exhibit an augmented affinity for RAD51, thereby enhancing HDR efficiency across various genomic loci and cell types when cooperated with Cas9, nCas9, and Cas12a. By combining with an inhibitor of non-homologous end joining (NHEJ) or the HDRobust strategy, these modular ssDNA donors achieve up to 90.03% (median 74.81%) HDR efficiency. The HDR-boosting modules targeting an endogenous protein enable a chemical modification-free strategy to improve the efficacy of ssDNA donors for precise gene editing.


Asunto(s)
ADN de Cadena Simple , Edición Génica , Recombinasa Rad51 , Reparación del ADN por Recombinación , ADN de Cadena Simple/metabolismo , ADN de Cadena Simple/genética , Humanos , Edición Génica/métodos , Recombinasa Rad51/metabolismo , Recombinasa Rad51/genética , Sistemas CRISPR-Cas , Células HEK293 , Proteínas Asociadas a CRISPR/metabolismo , Proteínas Asociadas a CRISPR/genética , Proteína 9 Asociada a CRISPR/metabolismo , Proteína 9 Asociada a CRISPR/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Endodesoxirribonucleasas/metabolismo , Endodesoxirribonucleasas/genética , Reparación del ADN por Unión de Extremidades
9.
Dalton Trans ; 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39136437

RESUMEN

The synthesis, spectroscopic characterisation and catalytic olefin polymerisation behaviour of a class of binuclear titanium bis(benzyl) complexes bearing bis-(pyridine-2-phenolate-6-methine)-[µ-(arylene-1,4-diyl-2,3-X2)] ligands [X2 = -C4H4- (1), F2 (2), H2 (3)], and mononuclear analogues, are described. These bimetallic catalyst frameworks are designed to exhibit a degree of conformational flexibility, which is regulated by steric effects and crucially permits tuning of intermetallic distances and geometry, yet their shape-persistent nature can also confer favourable entropic terms. Complexes 1-3 are characterised as two diastereomers [meso (RS) and rac (RR,SS)] in ratios of 1.32, 1.18 and 1.13 respectively, according to 1H NMR spectroscopy. In contrast to 3, [1H,1H]-ROESY experiments for 1 and 2 revealed that the X2 substituents can impose preferred conformations with syn orientations of Ti2 centres and benzyl groups, thus implying that the activated catalysts would present binding sites with the same direction of access. For ethylene-(1-octene) copolymerisation reactions, in conjunction with [Ph3C][B(C6F5)4], catalyst 1 displayed superior efficiencies and produced polymers with higher Mw values and enhanced comonomer incorporation ratios (up to 41%), when compared with the mononuclear 5m (22%). These results are indicative of enhanced comonomer enchainment and cooperative reactivity by the Ti2 sites.

10.
Life Sci ; : 122949, 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39127318

RESUMEN

Vital organ injury is one of the leading causes of global mortality and socio-economic burdens. Current treatments have limited efficacy, and new strategies are needed. Dexmedetomidine (DEX) is a highly selective α2-adrenergic receptor that protects multiple organs by reducing inflammation and preventing cell death. However, its exact mechanism is not yet fully understood. Understanding the underlying molecular mechanisms of its protective effects is crucial as it could provide a basis for designing highly targeted and more effective drugs. Ferroptosis is the primary mode of cell death during organ injury, and recent studies have shown that DEX can protect vital organs from this process. This review provides a detailed analysis of preclinical in vitro and in vivo studies and gains a better understanding of how DEX protects against vital organ injuries by inhibiting ferroptosis. Our findings suggest that DEX can potentially protect vital organs mainly by regulating iron metabolism and the antioxidant defense system. This is the first review that summarizes all evidence of ferroptosis's role in DEX's protective effects against vital organ injuries. Our work aims to provide new insights into organ therapy with DEX and accelerate its translation from the laboratory to clinical settings.

11.
Environ Pollut ; 360: 124653, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39095002

RESUMEN

Protozoa play a pivotal role in the microbial cycle, and ciliated protozoan grazing habits are associated with dimethyl sulfide (DMS) cycle. Many studies have explored the impacts of nanoplastics (NPs) and microplastics (MPs) on ecotoxicological effects of ciliates. However, limited research exists on NPs and MPs influences on the production of organic sulfur compounds. The impact of NPs and MPs on the production of dimethyl sulfoxide (DMSO) and carbonyl sulfide (COS) remains unclear. Therefore, we examined the impacts of three concentrations (1 × 105, 5 × 105, and 1 × 106 items/mL) of polystyrene (PS) NPs (50 nm) and MPs (1 and 5 µm) on the ecotoxicology and DMS/dimethylsulfoniopropionate (DMSP)/DMSO/COS production in the ciliate Uronema marinum. NPs and MPs exposure were found to reduce the abundance, growth rate, volume, and biomass of U. marinum. Additionally, NPs and MPs increased the superoxide anion radical (O2˙─) production rates and malondialdehyde (MDA) contents (24 h), leading to a decline in glutathione (GSH) content and an ascend in superoxide dismutase (SOD) activity to mitigate the effects of reactive oxygen species (ROS). Exposure to PS NPs and MPs decreased the ingestion rates of algae by 7.5-14.4%, resulting in decreases in DMS production by 56.8-85.4%, with no significant impact on DMSO production. The results suggest a distinct pathway for the production of DMSO or COS compared to DMS. These findings help us to understand the NPs and MPs impacts on the marine ecosystem and organic sulfur compound yield, potentially influencing the global climate.

12.
Nat Commun ; 15(1): 6624, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39103352

RESUMEN

Electrocatalytic H2 production from seawater, recognized as a promising technology utilizing offshore renewables, faces challenges from chloride-induced reactions and corrosion. Here, We introduce a catalytic surface where OH- dominates over Cl- in adsorption and activation, which is crucial for O2 production. Our NiFe-based anode, enhanced by nearby Cr sites, achieves low overpotentials and selective alkaline seawater oxidation. It outperforms the RuO2 counterpart in terms of lifespan in scaled-up stacks, maintaining stability for over 2500 h in three-electrode tests. Ex situ/in situ analyses reveal that Cr(III) sites enrich OH-, while Cl- is repelled by Cr(VI) sites, both of which are well-dispersed and close to NiFe, enhancing charge transfer and overall electrode performance. Such multiple effects fundamentally boost the activity, selectively, and chemical stability of the NiFe-based electrode. This development marks a significant advance in creating durable, noble-metal-free electrodes for alkaline seawater electrolysis, highlighting the importance of well-distributed catalytic sites.

13.
BMC Cancer ; 24(1): 968, 2024 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-39112971

RESUMEN

INTRODUCTION: The estimated dose of radiation to immune cells (EDRIC) has been shown to correlate with the overall survival (OS) of patients who receive definitive thoracic radiotherapy. However, the planning target volume (PTV) may be a confounding factor. We assessed the prognostic value of EDRIC for non-small cell lung cancer (NSCLC) in patients who underwent postoperative radiotherapy (PORT) with homogeneous PTV. METHODS: Patients with NSCLC who underwent PORT between 2004 and 2019 were included. EDRIC was computed as a function of the number of radiation fractions and mean doses to the lungs, heart, and remaining body. The correlations between EDRIC and OS, disease-free survival (DFS), locoregional-free survival (LRFS), and distant metastasis-free survival (DMFS) were analyzed using univariate and multivariate Cox models. Kaplan-Meier analysis was performed to assess the survival difference between low- and high-EDRIC groups. RESULTS: In total, 345 patients were analyzed. The mean EDRIC was 6.26 Gy. Multivariate analysis showed that higher EDRIC was associated with worse outcomes in terms of OS (hazard ratio [HR] 1.207, P = .007), DFS (HR 1.129, P = .015), LRFS (HR 1.211, P = .002), and DMFS (HR 1.131, P = .057). In the low- and high-EDRIC groups, the 3-year OS was 81.2% and 74.0%, DFS 39.8% and 35.0%, LRFS 70.4% and 60.5%, and DMFS 73.9% and 63.1%, respectively. CONCLUSIONS: EDRIC is an independent prognostic factor for survival in patients with NSCLC undergoing PORT. Higher doses of radiation to the immune system are associated with tumor progression and poor survival. Organs at risk for the immune system should be considered during radiotherapy planning.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Carcinoma de Pulmón de Células no Pequeñas/cirugía , Masculino , Femenino , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/inmunología , Persona de Mediana Edad , Anciano , Pronóstico , Estudios Retrospectivos , Dosificación Radioterapéutica , Adulto , Anciano de 80 o más Años , Estimación de Kaplan-Meier , Supervivencia sin Enfermedad , Radioterapia Adyuvante
14.
Phytother Res ; 2024 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-39098645

RESUMEN

Inflammatory osteolysis is often caused by the excessive activation of osteoclasts stimulated by bacterial products such as lipopolysaccharide. The natural flavonoid trifolirhizin (TRI) has anti-inflammatory properties; however, its function in inflammatory bone lysis remains unclear. This study aimed to elucidate the potential regulatory mechanisms of TRI in osteoclasts.Tartrate-resistant acid phosphatase (TRAP) staining, acid secretion assays, podosomal actin belt fluorescence staining, and bone resorption assays were used to investigate the effects of TRI on osteoclast differentiation and bone resorption. A reactive oxygen species (ROS) measurement kit was used to detect the effect of TRI on ROS levels in osteoclasts. The effects of TRI on genes and signaling pathways related to osteoclast differentiation were determined by quantitative polymerase chain reaction (qPCR) and western blotting. A mouse model of lipopolysaccharide-mediated inflammatory osteolysis was established, and the effects of TRI treatment on bone mass were observed using micro-CT and histological examination. Mechanistically, TRI reduced ROS production by inhibiting receptor activator of nuclear factor-κB ligand (RANKL)-induced activation of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, and by upregulating the expression levels of the anti-ROS enzymes heme oxygenase-1 (HO-1) and catalase (CAT), which contributed to the degradation of ROS, ultimately leading to a decrease in osteoclastogenesis. TRI inhibited osteoclast formation and ameliorated lipopolysaccharide (LPS)-mediated inflammatory osteolysis. Thus, TRI may be a candidate agent for anti-inflammatory osteolysis.

15.
ACS Nano ; 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39102015

RESUMEN

The ligand effect in alloy catalysts is one of the decisive parameters of the catalytic performance. However, the strong interrelation between the ligand effect and the geometric effect of the active atom and its neighbors as well as the systematic alteration of the microenvironment of the active site makes the active mechanism unclear. Herein, Pt3Tm, Pt3Yb, and Pt3Lu with a cubic crystal system (Pm-3m) were selected. With the difference of Pt-Pt interatomic distance within 0.02 Å, we minimize the geometric effect to realize the disentanglement of the system. Through precise characterization, due to the low electronegativity of Ln (Ln = Tm, Yb, and Lu) and the ligand effect in the alloy, the electronic structure of Pt is continuously optimized, which improves the electrochemical methanol oxidation reaction (MOR) performance. The Ln electronegativity has a linear relationship with the MOR performance, and Pt3Yb/C achieves a high mass activity of up to 11.61 A mgPt-1, which is the highest value reported so far in Pt-based electrocatalysts. The results obtained in this study provide fundamental insights into the mechanism of ligand effects on the enhancement of electrochemical activity in rare-earth nanoalloys.

16.
Diabetol Metab Syndr ; 16(1): 188, 2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39095824

RESUMEN

AIMS: The triglyceride-glucose (TyG) index and hypertension (HTN) are established risk factors of CVD. However, there is a dearth of studies investigating the synergistic influence of the elevated TyG index and HTN on CVD risk, as well as any potential interaction between these factors. METHOD: For this investigation, we enlisted 88,384 individuals from the Kailuan Study who did not have a history of stroke, myocardial infarction, or cancer at baseline. Incidences of CVD between 2006 and 2021 were confirmed through a thorough review of medical records. Participants were categorized into 6 groups according to BP status(normal/elevated BP, stage 1 and stage 2) or the TyG index(low and elevated group), respectively. The Cox proportional hazard regression models were used to assess the association of BP status and TyG index with incident CVD. The multiplicative and additive interactions were also determined. RESULTS: Following a mean follow-up period of 13.66 ± 3.24 years, incidents of CVD, MI, and stroke were observed in 8,205, 1,728, and 6,705 individuals, respectively. The BP category and TyG index additively increased the risk of CVD, MI and stroke. There were significant interacting and joint effects of TyG index and BP status on CVD risk. Additionally, stratification analysis further confirmed that the relative contribution of hypertension to the CVD development decreased with deteriorating TyG index and that of TyG index was attenuated with increasing BP status. CONCLUSION: Our study demonstrated that a significant interaction between TyG index and BP status on the risk of CVD.

17.
ACS Omega ; 9(31): 33574-33593, 2024 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-39130575

RESUMEN

Osteolytic diseases such as osteoporosis and neoplastic bone metastases are caused by the excessive activation of osteoclasts. Inhibiting the excessive activation of osteoclasts is a crucial strategy for treating osteolytic diseases. This study investigated the roles and mechanisms of regorafenib, a tyrosine kinase inhibitor, on osteoclasts and osteolytic diseases. We first identified the potential targets and mechanisms of regorafenib on osteoclast-related osteolytic diseases using network pharmacological analysis and molecular docking techniques. Then, we verified its role and mechanism on osteoclasts via cellular and animal experiments. Network pharmacology analysis identified 89 common targets shared by regorafenib and osteoclast-related osteolytic diseases. Enrichment analysis suggested that regorafenib may act on osteoclast-related osteolytic diseases by modulating targets such as AKT1, CASP3, MMP9, and MAPK3, regulating biological processes such as cell proliferation, apoptosis, and phosphorylation regulation, and influencing signaling pathways such as MAPK, PI3K/AKT, and osteoclast differentiation. The molecular docking results indicated that regorafenib and AKT1, CASP3, MMP9, MAPK3, and MAPK14 were stably docked. Cell experiments demonstrated that regorafenib significantly inhibited osteoclast differentiation and bone resorption in RAW 264.7 cells and bone marrow macrophages in a dose-dependent manner, with up to 50% reduction at 800 nM concentration without exhibiting cytotoxic effects. Furthermore, Western blot and RT-qPCR results demonstrated that regorafenib inhibited osteoclast differentiation by blocking the transduction of RANKL-induced NF-κB, p38, ERK, and NFAT signaling pathways. In vivo studies using an ovariectomized mouse model showed that regorafenib significantly improved bone volume fraction (BV/TV), bone surface to total volume (BS/TV), and number of trabeculae (TB.N), as well as reduced trabecular separation (Tb.Sp) compared to the OVX groups (P < 0.05). TRAcP staining results revealed a reduction in the number of osteoclasts with regorafenib treatment (P < 0.01). These results indicate that regorafenib exerts its protective effects against osteoclast-related osteolytic disease by inhibiting the RANKL-induced NF-κB, NFAT, ERK, and p38 signaling pathways. This study proves that regorafenib may serve as a potential therapeutic agent for osteoclast-related osteolytic diseases.

18.
J Oral Rehabil ; 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-39135294

RESUMEN

BACKGROUND: Aberrant occlusion and aging are two main risks for temporomandibular joint (TMJ) degeneration. OBJECTIVE: To assess the combined impact of occlusion and age on TMJ disc. METHODS: To avoid the confounding impact of gender, presently, 126 female C57BL/6J mice, 63 youngsters, 6-week old and 63 adults, 28-week old, were used. An experimental bilateral anterior crossbite (BAC) relation was created by installing metal tubes onto the mandibular incisors. Mice were sacrificed at 3, 7 and 11 weeks (n = 9). Additionally, the installed tubes were removed at 7 weeks in removal groups and the TMJs were sampled after another 4 weeks (n = 9). Disc changes were detected by histomorphology, immunohistochemistry, and western blot assays. RESULTS: Disc deformation was obvious in BAC groups. The typical change was hyperplasia at the posterior region of the disc where there was significant infiltration of inflammatory cells. Expressions of the inflammatory markers, including tumour necrosis factor-α and interleukin-1ß, and the catabolic markers, including fibronectin (FN), FN N-terminal fragments, and vascular endothelial growth factor-A, were all increased. The changes were more obvious in adults than in youngsters. Removal of BAC attenuated inflammatory and catabolic changes in the youngsters, but the inflammatory markers recovered little in the adults. CONCLUSION: TMJ disc responds to BAC by degeneration and inflammation, and respond to BAC removal by rehabilitation. Adult discs show severer degeneration responses to BAC and a lower level of anti-inflammatory capability to BAC removal than the youngster's discs. Animals cannot be equated with humans. The human disc response to occlusion changes worth further exploration.

19.
Nanoscale ; 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39135495

RESUMEN

Functional amyloids formed by the protein FapC in Pseudomonas bacteria are key structural components of Pseudomonas biofilms, which mediate chronic infections and also contribute to antimicrobial resistance. Here, we combine kinetic experiments with mechanistic modelling to probe the role of surfaces in FapC functional amyloid formation. We find that nucleation of new fibrils is predominantly heterogeneous in vitro, being catalysed by reaction vessel walls but not by the air/water interface. Removal of such interfaces by using microdroplets greatly slows heterogeneous nucleation and reveals a hitherto undetected fibril surface-catalysed "secondary nucleation" reaction step. We tune the degree of catalysis by varying the interface chemistry of the reaction vessel and by adding nanoparticles with tailored surface properties that catalyse fibril nucleation. In so doing, we discover that the rate of nucleation is controlled predominantly by the strength with which FapC binds to the catalytic sites on the interface, and by its surface area. Surprisingly, neither primary nucleation rate nor catalytic site binding strength appear closely correlated to the charge and hydrophilicity of the interface. This indicates the importance of considering experimental design in terms of surface chemistry of the reaction container while also highlighting the notion that fibril nucleation during protein aggregation is a heterogeneous process.

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