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Target protein degradation (TPD) has emerged as a revolutionary approach in drug discovery, leveraging the cell's intrinsic machinery to selectively degrade disease-associated proteins. Nanoluciferase (nLuc) fusion proteins and the NanoBiT technology offer two robust and sensitive screening platforms to monitor the subtle changes in protein abundance induced by TPD molecules. Despite these advantages, concerns have arisen regarding potential degradation artifacts introduced by tagging systems due to the presence of lysine residues on them, prompting the development of alternative tools. In this study, we introduce HiBiT-RR and nLucK0, variants devoid of lysine residues, to mitigate such artifacts. Our findings demonstrate that HiBiT-RR maintains a similar sensitivity and binding affinity with the original HiBiT. Moreover, the comparison between nLucWT and nLucK0 constructs reveals variations in degradation patterns induced by certain TPD molecules, emphasizing the importance of choosing appropriate tagging systems to ensure the reliability of experimental outcomes in studying protein degradation processes.
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The use of mesenchymal stromal cells (MSCs) for treating chronic inflammatory disorders, wounds, and ischemia-reperfusion injuries has shown improved healing efficacy. However, the poor survival rate of transplanted cells due to oxidative stress in injured or inflamed tissue remains a significant concern for MSC-based therapies. In this study, we developed a new approach to protect MSCs from oxidative stress, thereby improving their survival in a wound microenvironment and enhancing their therapeutic effect. We produced PLGA nanoparticles loaded with the cytoprotective phytochemical silibinin (SBN), and used them to modify MSCs. Upon internalization, these nanoformulations released SBN, activating the Nrf2/ARE signaling pathway, resulting in threefold reduction in intracellular ROS content and improved cell survival under oxidative stress conditions. Modification of MSCs with SBN-loaded PLGA nanoparticles increased their survival upon transplantation to full-thickness cutaneous wounds and improved wound healing. This study suggests that MSC modification with cytoprotective nanoparticles could be a promising approach for improving wound healing.
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PURPOSE: To investigate the prevalence and body mass index (BMI) associations of congenital lower epiblepharon in children in China and the difference in the refractive errors between children with and without epiblepharon. METHODS: Children 6-12 years of age in Beichen District of Tianjin were screened for congenital epiblepharon from September to October 2017. All children underwent slit-lamp examination, strabismus screening, visual acuity examination and refraction. Weight and height were also recorded. The prevalence of lower epiblepharon in school-age children was evaluated, and its association with age, sex, BMI, and refractive error was analyzed. RESULTS: A total of 28,225 children were examined; 564 had epiblepharon. The prevalence of epiblepharon was found to be, for 6-year-olds, 2.50%; for 7-year-olds, 2.13%; for 8-year-olds, 2.10%; for 9-year-olds, 1.97%; for 10-year-olds, 1.85%; for 11-year-olds, 1.67%; and for 12-year-olds, 1.19% (P < 0.05). The prevalence of overweight and obesity in children with epiblepharon was found to be 16.7% and 47.2%, respectively. The prevalence and degree of astigmatism was higher than in nonepiblepharon children. We found a possible association between severity of astigmatism and severity of epiblepharon. CONCLUSIONS: In our study, the prevalence of epiblepharon decreased with advancing age, and the majority of children with epiblepharon were found to be overweight or obese. Epiblepharon was associated with astigmatism.
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Doenças Palpebrais , Pálpebras , Criança , Feminino , Humanos , Masculino , Índice de Massa Corporal , China/epidemiologia , Estudos Transversais , População do Leste Asiático , Doenças Palpebrais/congênito , Pálpebras/anormalidades , Prevalência , Refração Ocular , Erros de Refração/epidemiologia , Acuidade VisualRESUMO
Target protein degradation (TPD) has emerged as a revolutionary approach in drug discovery, leveraging the cell's intrinsic machinery to selectively degrade disease-associated proteins. Proteolysis-Targeting Chimeras (PROTACs) exemplify this strategy, exploiting heterobifunctional molecules to induce ubiquitination and subsequent degradation of target proteins. The clinical advancement of PROTACs underscores their potential in therapeutic intervention, with numerous projects progressing through clinical stages. However, monitoring subtle changes in protein abundance induced by TPD molecules demands highly sensitive assays. Nano-luciferase (nLuc) fusion proteins, or the NanoBiT technology derived from it, offer a robust screening platform due to their high sensitivity and stability. Despite these advantages, concerns have arisen regarding potential degradation artifacts introduced by tagging systems due to the presence of lysine residues on them, prompting the development of alternative tools. In this study, we introduce HiBiT-RR and nLuc K0 , variants devoid of lysine residues, to mitigate such artifacts. Our findings demonstrate that HiBiT-RR maintains similar sensitivity and binding affinity with the original HiBiT. Moreover, the comparison between nLuc WT and nLuc K0 constructs reveals variations in degradation patterns induced by certain PROTAC molecules, emphasizing the importance of choosing appropriate tagging systems to ensure the reliability of experimental outcomes in studying protein degradation processes.
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PURPOSE: This study aims to elucidate the longitudinal refractive and ocular biometric alterations in preschool children with high hyperopia who underwent early interventions. METHODS: We conducted a retrospective analysis of preschool children diagnosed with high hyperopia at Tianjin Medical University Eye Hospital between 2011 and 2023. Inclusion criteria required an initial examination with cycloplegic refraction, bilateral spherical equivalent power (SE) ≥ +5.00D with a difference <1.00D, a minimum two-year follow-up, and at least three ocular biometric measurements. The annual axial growth rate evaluated emmetropization in highly hyperopic children. We applied Restricted Cubic Spline (RCS) models to explore potential nonlinear relationships between age and spherical equivalent, axial length, corneal curvature, and axial length-to-corneal curvature ratio. Additionally, Mixed-effects models were employed to investigate factors associated with changes in refractive error and axial length. RESULTS: The study enrolled 60 eligible subjects, with a median initial diagnosis age of 3.5 years (IQR, 2.8-4.9 years) and a median last visit age of 9.3 years (IQR, 8.1-10.8 years). The average follow-up duration was 5.7 years. RCS analysis revealed notable nonlinear changes in spherical equivalent power, axial length, and axial length-to-corneal curvature ratio, although corneal curvature displayed no statistically significant nonlinear trend. Factors affecting SE changes included the presence of strabismus, the use of cycloplegia, baseline SE, and age. Conversely, changes in axial length solely correlated with baseline axial length and age. CONCLUSION: Highly hyperopic preschool children undergoing early intervention display a marked emmetropization tendency, though most still remain moderately to highly hyperopic, with the progression of refractive changes showing non-uniform patterns with respect to age.
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Comprimento Axial do Olho , Hiperopia , Refração Ocular , Humanos , Hiperopia/fisiopatologia , Hiperopia/diagnóstico , Pré-Escolar , Refração Ocular/fisiologia , Masculino , Estudos Retrospectivos , Feminino , Seguimentos , Comprimento Axial do Olho/patologia , Acuidade Visual/fisiologia , Criança , Biometria , Córnea/fisiopatologia , Córnea/patologia , Oftalmopatias HereditáriasRESUMO
The scaffolding function of receptor interacting protein kinase 1 (RIPK1) confers intrinsic and extrinsic resistance to immune checkpoint blockades (ICBs) and has emerged as a promising target for improving cancer immunotherapies. To address the challenge posed by a poorly defined binding pocket within the intermediate domain, we harnessed proteolysis targeting chimera (PROTAC) technology to develop a first-in-class RIPK1 degrader, LD4172. LD4172 exhibited potent and selective RIPK1 degradation both in vitro and in vivo . Degradation of RIPK1 by LD4172 triggered immunogenic cell death (ICD) and enriched tumor-infiltrating lymphocytes and substantially sensitized the tumors to anti-PD1 therapy. This work reports the first RIPK1 degrader that serves as a chemical probe for investigating the scaffolding functions of RIPK1 and as a potential therapeutic agent to enhance tumor responses to immune checkpoint blockade therapy.
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The scaffolding function of receptor interacting protein kinase 1 (RIPK1) confers intrinsic and extrinsic resistance to immune checkpoint blockades (ICBs) and has emerged as a promising target for improving cancer immunotherapies. To address the challenge posed by a poorly defined binding pocket within the intermediate domain, we harnessed proteolysis targeting chimera (PROTAC) technology to develop a first-in-class RIPK1 degrader, LD4172. LD4172 exhibited potent and selective RIPK1 degradation both in vitro and in vivo. Degradation of RIPK1 by LD4172 triggered immunogenic cell death (ICD) and enriched tumor-infiltrating lymphocytes and substantially sensitized the tumors to anti-PD1 therapy. This work reports the first RIPK1 degrader that serves as a chemical probe for investigating the scaffolding functions of RIPK1 and as a potential therapeutic agent to enhance tumor responses to immune checkpoint blockade therapy.
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Rivers serve as the primary pathway for transporting floating marine litter (FML) from land to sea. However, the complex dynamics of transboundary rivers pose a significant obstacle when examining the impact of watershed-based human activities on FML distribution. This study conducts year-long monthly monitoring of FML using trawl and visual surveys in the coastal water of a peninsula dominated by indigenous rivers in south China. Overall, small pieces debris dominates FML in the nearshore waters of the peninsula, with meso-sized (0.5 cm-2.5 cm) FML accounting for 73.93 % of the total. The density of FML is more profoundly influenced by human activities within watersheds rather than its composition. Moreover, the association between human activity and FML density exhibits greater significant compared to variations based on geography and seasonality. This study provides a scientific basis for coastal protection and contributes for understanding of the mechanisms of marine litter transfer from land to sea.
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Fluormetolona , Plásticos , Humanos , Monitoramento Ambiental , Resíduos/análise , GeografiaRESUMO
Rice root characteristics are tightly associated with high-efficient nitrogen uptake. To understand the relationship of root plastic responses with nitrogen uptake when reducing nitrogen application for green rice production, a hydroponic experiment and a soil pot experiment were conducted under high (HN) and low (LN) nitrogen applications, using two rice (Oryza sativa L.) varieties, NK57 and YD6, three nitrogen absorption traits (total nitrogen accumulation, net NH4 + influx on root surface, nitrogen uptake via apoplasmic pathway) and root characteristics were investigated. In comparison with HN, LN significantly reduced nitrogen absorption and grain yield in both varieties. Concomitantly, there was a decrease in total root length, root surface area, root number, root volume, and root cortical area under LN, while single root length, root aerenchyma area, and root lignin content increased. The expression of OsAMT1;1 and OsAMT1;2 down-regulated in both varieties. The findings revealed that YD6 had smaller reduction degree for the three nitrogen absorption traits and grain yield, accompanied by smaller reduction degree in total root length, root surface area, root cortical area, and expression of the two genes under LN. These root characteristics were significantly and positively correlated with the three nitrogen absorption traits and grain yield, especially under LN. These results indicate that a large root system, lower reduction degree in several root characters, and high expression of OsAMT genes in YD6 explains its high nitrogen accumulation and grain yield under reduced nitrogen application. The study may provide rationale for developing varieties with low nitrogen fertilizer requirements for enabling green rice production.
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Metal-organic framework nanoparticles (nanoMOFs) are promising nanomaterials for biomedical applications. Some of them, including biodegradable porous iron carboxylates are proposed for encapsulation and delivery of antibiotics. Due to the high drug loading capacity and fast internalization kinetics, nanoMOFs are more beneficial for the treatment of intracellular bacterial infections compared to free antibacterial drugs, which poorly accumulate inside the cells because of the inability to cross membrane barriers or have low intracellular retention. However, nanoparticle internalization does not ensure their accumulation in the cell compartment that shelters a pathogen. This study shows the availability of MIL-100(Fe)-based MOF nanoparticles to co-localize with Chlamydia trachomatis, an obligate intracellular bacterium, in the infected RAW264.7 macrophages. Furthermore, nanoMOFs loaded with photosensitizer methylene blue (MB) exhibit complete photodynamic inactivation of C. trachomatis growth. Simultaneous infection and treatment of RAW264.7 cells with empty nanoMOFs resulted in a bacterial load reduction from 100 to 36% that indicates an intrinsic anti-chlamydial effect of this iron-containing nanomaterial. Thus, our findings suggest the use of iron-based nanoMOFs as a promising drug delivery platform, which contributes to antibacterial effect, for the treatment of chlamydial infections.
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Chlamydia trachomatis , Azul de Metileno , Chlamydia trachomatis/fisiologia , Azul de Metileno/farmacologia , Antibacterianos/farmacologia , Sistemas de Liberação de Medicamentos , FerroRESUMO
Reduction oxidation (redox) reactions are central in life and altered redox state is associated with a spectrum of human diseases. Glutathione (GSH) is the most abundant antioxidant in eukaryotic cells and plays critical roles in maintaining redox homeostasis. Thus, measuring intracellular GSH level is an important method to assess the redox state of organism. The currently available GSH probes are based on irreversible chemical reactions with glutathione and can't monitor the real-time glutathione dynamics. Our group developed the first reversible reaction based fluorescent probe for glutathione, which can measure glutathione levels at high resolution using a confocal microscope and in the bulk scale with a flow cytometry. Most importantly it can quantitatively monitor the real-time GSH dynamics in living cells. Using the 2 nd generation of GSH probe, RealThiol (RT), this study measured the GSH level in living Hela cells after treatment with varying concentrations of DL-Buthionine sulfoximine (BSO) which inhibits GSH synthesis, using a high throughput imaging system, Cytation™ 5 cell imaging reader. The results revealed that GSH probe RT at the concentration of 2.0 µM accurately monitored the BSO treatment effect on GSH level in the Hela cells. The present results demonstrated that the GSH probe RT is sensitive and precise in GSH measurement in living cells at a high throughput imaging platform and has the potential to be applied to any cell lines.
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Brain research is an area of research characterized by its cutting-edge nature, with brain mapping constituting a crucial aspect of this field. As sequencing tools have played a crucial role in gene sequencing, brain mapping largely depends on automated, high-throughput and high-resolution imaging techniques. Over the years, the demand for high-throughput imaging has scaled exponentially with the rapid development of microscopic brain mapping. In this paper, we introduce the novel concept of confocal Airy beam into oblique light-sheet tomography named CAB-OLST. We demonstrate that this technique enables the high throughput of brain-wide imaging of long-distance axon projection for the entire mouse brain at a resolution of 0.26 µm × 0.26 µm × 1.06 µm in 58 hours. This technique represents an innovative contribution to the field of brain research by setting a new standard for high-throughput imaging techniques.
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Light is essential for the growth and defense of soybean. It is not clear how soybeans adjust their defenses to different light environments with different cropping patterns. The mechanism of soybean response to Soybean mosaic virus (SMV) infection under different light intensities was analyzed by RNA-seq sequencing method. Enrichment analysis illustrated that most defense-related genes were down-regulated in the dark and the shade, and up-regulated under hard light and normal light. Soybean can resist SMV infection mainly by activating salicylic acid signaling pathway. Light is essential for activating salicylic acid defense signaling pathways. With the increase of light intensity, the oxidative damage of soybean leaves was aggravated, which promoted the infection of virus. When light was insufficient, the growth of soybean was weak, and the plant-pathogen interaction pathway, MAPK pathway and hormone defense pathway in infected soybean was inhibited. Under hard light, some defense genes in infected soybean were down-regulated to reduce the degree of oxidative damage. The expression of differentially expressed genes was verified by real-time fluorescence quantitative RT-PCR. In order to adapt to the change of light intensity, soybean balanced allocation of resources between growth and defense through a series regulation of gene expression. The results of this study will provide a theoretical basis for the research of SMV resistance in intercropping soybean.
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Metal-organic frameworks (MOFs) are a highly versatile class of ordered porous materials, which hold great promise for different biomedical applications, including antibacterial therapy. In light of the antibacterial effects, these nanomaterials can be attractive for several reasons. First, MOFs exhibit a high loading capacity for numerous antibacterial drugs, including antibiotics, photosensitizers, and/or photothermal molecules. The inherent micro- or meso-porosity of MOF structures enables their use as nanocarriers for simultaneous encapsulation of multiple drugs resulting in a combined therapeutic effect. In addition to being encapsulated into an MOF's pores, antibacterial agents can sometimes be directly incorporated into an MOF skeleton as organic linkers. Next, MOFs contain coordinated metal ions in their structure. Incorporation of Fe2/3+, Cu2+, Zn2+, Co2+, and Ag+ can significantly increase the innate cytotoxicity of these materials for bacteria and cause a synergistic effect. Finally, abundance of functional groups enables modifying the external surface of MOF particles with stealth coating and ligand moieties for improved drug delivery. To date, there are a number of MOF-based nanomedicines available for the treatment of bacterial infections. This review is focused on biomedical consideration of MOF nano-formulations designed for the therapy of intracellular infections such as Staphylococcus aureus, Mycobacterium tuberculosis, and Chlamydia trachomatis. Increasing knowledge about the ability of MOF nanoparticles to accumulate in a pathogen intracellular niche in the host cells provides an excellent opportunity to use MOF-based nanomedicines for the eradication of persistent infections. Here, we discuss advantages and current limitations of MOFs, their clinical significance, and their prospects for the treatment of the mentioned infections.
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BACKGROUND: Cisplatin (CDDP) is a mainstay treatment for advanced head and neck squamous cell carcinomas (HNSCC) despite a high frequency of innate and acquired resistance. We hypothesised that tumours acquire CDDP resistance through an enhanced reductive state dependent on metabolic rewiring. METHODS: To validate this model and understand how an adaptive metabolic programme might be imprinted, we performed an integrated analysis of CDDP-resistant HNSCC clones from multiple genomic backgrounds by whole-exome sequencing, RNA-seq, mass spectrometry, steady state and flux metabolomics. RESULTS: Inactivating KEAP1 mutations or reductions in KEAP1 RNA correlated with Nrf2 activation in CDDP-resistant cells, which functionally contributed to resistance. Proteomics identified elevation of downstream Nrf2 targets and the enrichment of enzymes involved in generation of biomass and reducing equivalents, metabolism of glucose, glutathione, NAD(P), and oxoacids. This was accompanied by biochemical and metabolic evidence of an enhanced reductive state dependent on coordinated glucose and glutamine catabolism, associated with reduced energy production and proliferation, despite normal mitochondrial structure and function. CONCLUSIONS: Our analysis identified coordinated metabolic changes associated with CDDP resistance that may provide new therapeutic avenues through targeting of these convergent pathways.
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Antineoplásicos , Neoplasias de Cabeça e Pescoço , Humanos , Cisplatino/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Fator 2 Relacionado a NF-E2/genética , Resistencia a Medicamentos Antineoplásicos/genética , Linhagem Celular Tumoral , Glucose , Antineoplásicos/farmacologiaRESUMO
BACKGROUND: There are some uncertainties about the effect of low-power red laser treatment on myopia control for anisometropic myopia in children. To evaluate the effect and safety of low-power red laser treatment on refractive development for anisometropic myopia in children, a contralateral comparison study was conducted. METHODS: The more myopic eye of child with anisometropic myopia was treated with low-power red laser treatment (LRL group), the other eye received no treatment other than the wearing of single-focus spectacles (SFS) (SFS Group). The LRL treatment was given at home under parental guidance for 3 minutes each time, twice daily with a minimal interval of 4 hours, 7 days per week, using an equipment that produces red laser of 650 nm wavelength at an illuminance range of roughly 1200-1800 lux and an energy of 0.60 mw for a 4-mm pupil (class I classification). RESULTS: Among 51 included children, 44 (86.27%) completed the 3-months study, consisting of 15 girls (34.1%) and 29 boys (65.9%). After 3-months axial length (AL) and spherical equivalent refraction (SER) progression were -0.08 mm [95% CI (confidence interval), 0.11 to 0.06 mm] and +0.23 diopter (D) (95% CI, 0.13-0.33 D) for LRL group and +0.08 mm (95% CI, 0.05-0.11 mm) and -0.07 D (95% CI, -0.16-0.03 D) for SFS group. AL and SER progression between the groups varied by 0.17 mm (95% CI, 0.13-0.20 mm) and -0.30 D (95% CI, -0.42 to -0.18 D). There was no visible structural damage on optical coherence tomography (OCT) scans. CONCLUSIONS: AL growth, myopia progression, and anisometropia of the binoculars can all be slowed down by LRL treatment. Compared to SER progression, axial elongation is more accurate and simpler to monitor. LRL treatment unrecorded functional and structural damage of binoculus.
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Anisometropia , Miopia , Masculino , Feminino , Humanos , Criança , Miopia/terapia , Refração Ocular , Progressão da Doença , LasersRESUMO
Transplantation of mesenchymal stromal cells (MSCs) provides a powerful tool for the management of multiple tissue injuries. However, poor survival of exogenous cells at the site of injury is a major complication that impairs MSC therapeutic efficacy. It has been found that tissue-oxygen adaptation or hypoxic pre-conditioning of MSCs could improve the healing process. Here, we investigated the effect of low oxygen tension on the regenerative potential of bone-marrow MSCs. It turned out that incubation of MSCs under a 5% oxygen atmosphere resulted in increased proliferative activity and enhanced expression of multiple cytokines and growth factors. Conditioned growth medium from low-oxygen-adapted MSCs modulated the pro-inflammatory activity of LPS-activated macrophages and stimulated tube formation by endotheliocytes to a much higher extent than conditioned medium from MSCs cultured in a 21% oxygen atmosphere. Moreover, we examined the regenerative potential of tissue-oxygen-adapted and normoxic MSCs in an alkali-burn injury model on mice. It has been revealed that tissue-oxygen adaptation of MSCs accelerated wound re-epithelialization and improved the tissue histology of the healed wounds in comparison with normoxic MSC-treated and non-treated wounds. Overall, this study suggests that MSC adaptation to 'physiological hypoxia' could be a promising approach for facilitating skin injuries, including chemical burns.
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Queimaduras Químicas , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Camundongos , Animais , Medula Óssea , Queimaduras Químicas/metabolismo , Oxigênio/metabolismo , Cicatrização , Hipóxia/metabolismo , Células-Tronco Mesenquimais/metabolismoRESUMO
Importance: Progression of myopia in a school-aged population due to home confinement (January to May 2021) during the COVID-19 pandemic has been previously reported. A key remaining question was whether the myopia spike in children aged 6 to 8 years persisted. Objective: To investigate the changes in refractive status and prevalence of myopia in school-aged children 1 year after home confinement ended in China. Design, Setting, and Participants: This cross-sectional study with a cohort substudy prospectively evaluated data from school-based photoscreening in Feicheng, China. Children aged 6 to 13 years participated in 8 screenings from 2015 to 2021. Exposures: Noncycloplegic photorefraction was conducted using the Spot Vision photoscreener. Main Outcomes and Measures: The main outcomes were the differences in spherical equivalent refraction (SER) and prevalence of myopia between 2020 (during home confinement) and 2021 (after home confinement). The SER was recorded for each child, and the prevalence of myopia was calculated annually for each age group. Results: A total of 325â¯443 children participated in the study (51.4% boys, 48.6% girls; age range, 6 to 13 years). Compared with 2020, the mean SER of children in 2021 increased significantly for those aged 6 (0.42 diopters [D]), 7 (0.41 D), and 8 (0.33 D) years. The prevalence of myopia in 2021 was similar to in 2019 for each age group (aged 6 years: 7.9% vs 5.7%; aged 7 years: 13.9% vs 13.6%; aged 8 years: 29.5% vs 26.2%). Both the prevalence of myopia and mean SER for these children returned to their prepandemic levels. Conclusions and Relevance: Compared with 2020, the prevalence of myopia among children aged 6 to 8 years in the 2021 screenings decreased, and the mean SER returned to prepandemic level. The refractive development in children aged 6 to 8 years may be most susceptible to environmental changes. These findings support the premise that age 6 to 8 years is a critical period for myopia development and suggest a need to focus preventive interventions for myopia control on children in this age range.
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COVID-19 , Miopia , Masculino , Feminino , Humanos , Criança , Adolescente , Seguimentos , Prevalência , Estudos Transversais , Pandemias , COVID-19/epidemiologia , Miopia/diagnóstico , Miopia/epidemiologia , Refração Ocular , China/epidemiologiaRESUMO
Cadmium (Cd2+) is a toxic heavy metal in the environment, posing severe damage to animal health and drinking water safety. The bacteria-algae consortium remediates environmental Cd2+ pollution by secreting chelating reagents, but the molecular mechanisms remain elusive. Here, we showed that Cellulosimicrobium sp. SH8 isolated from a Cd2+-polluted lake could interact with Synechocystis sp. PCC6803, a model species of cyanobacteria, in strengthening Cd2+ toxicity resistance, while SH8 or PCC6803 alone barely immobilized Cd2+. In addition, the SH8-PCC6803 consortium, but not SH8 alone, could grow in a carbon-free medium, suggesting that autotrophic PCC6803 enabled the growth of heterotrophic SH8. Totally, 12 metabolites were significantly changed when SH8 was added to PCC6803 culture in the presence of Cd2+ (PCC6803/Cd2+). Among them, kynurenic acid was the only metabolite that precipitated Cd2+. Remarkably, adding kynurenic acid increased the growth of PCC6803/Cd2+ by 14.1 times. Consistently, the expressions of kynA, kynB, and kynT genes, known to be essential for kynurenic acid synthesis, were considerably increased when SH8 was added to PCC6803/Cd2+. Collectively, kynurenic acid secreted by SH8 mitigates Cd2+ toxicity for algae, and algae provide organic carbon for the growth of SH8, unveiling a critical link that mediates beneficial bacteria-algae interaction to resist Cd2+.
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Actinomycetales , Intoxicação por Cádmio , Animais , Cádmio/toxicidade , Ácido Cinurênico , BactériasRESUMO
Multicellular 3D tumor models are becoming a powerful tool for testing of novel drug products and personalized anticancer therapy. Tumor spheroids, a commonly used 3D multicellular tumor model, more closely reproduce the tumor microenvironment than conventional 2D cell cultures. It should be noted that spheroids can be produced using different techniques, which can be subdivided into scaffold-free (SF) and scaffold-based (SB) methods. However, it remains unclear, to what extent spheroid properties depend on the method of their generation. In this study, we aimed to carry out a head-to-head comparison of drug sensitivity and molecular expression profile in SF and SB spheroids along with a monolayer (2D) cell culture. Here, we produced non-small cell lung cancer (NSCLC) spheroids based on human lung adenocarcinoma cell line A549. Drug sensitivity analysis of the tested cell cultures to five different chemotherapeutics resulted in IC50 (A549-SB) > IC50 (A549-SF) > IC50 (A549-2D) trend. It was found that SF and SB A549 spheroids displayed elevated expression levels of epithelial-to-mesenchymal transition (EMT) markers and proteins associated with drug resistance compared with the monolayer A549 cell culture. Enhanced drug resistance of A549-SB spheroids can be a result of larger diameters and elevated deposition of extracellular matrix (ECM) that impairs drug penetration into spheroids. Thus, the choice of the spheroid production method can influence the properties of the generated 3D cell culture and their drug resistance. This fact should be considered for correct interpretation of drug testing results.