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1.
Infect Drug Resist ; 16: 7547-7557, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38089960

RESUMEN

Background: Current information were still limited regarding clinical characteristics, diagnosis, and treatment efficacy of calcaneal osteomyelitis (CO). The present study summarized similarities and differences between diabetes-related CO (DRCO) and trauma-related CO (TRCO) based on synthesis analysis of literature-reported cases. Methods: We searched the PubMed, Embase, and Cochrane Library databases to find English studies reporting DRCO and TRCO published between January 2000 and December 2021. Effective data were extracted and synthesized for comparisons. Results: Altogether 108 studies with 278 DRCO and 403 TRCO patients were analyzed. The ratio of females among the DRCO patients was significantly higher than that of the TRCO patients (37.4% vs 24.3%, P < 0.001). The median age at diagnosis of the DRCO patients was statistically older than the TRCO patients (56 vs 44 years, P < 0.001). The median symptom duration of the DRCO patients was longer than the TRCO patients (4 vs 2 months, P = 0.136), with ulcer and sinus as the top symptoms for the DRCO and TRCO patients, respectively. The positive rate of pathogen culture for the DRCO patients was significantly higher than that for the TRCO patients (94.8% vs 69.5%, P < 0.001). The DRCO patients had higher risks of infection relapse (32.3% vs 16.3%, P < 0.001) and amputation (24.8% vs 1.4%, P < 0.001), and a higher all-cause mortality (4.9% vs 1.3%, P = 0.03) than the TRCO patients. Conclusion: DRCO and TRCO shared similar and different clinical features and diagnostic issues. However, compared with TRCO, the clinical efficacy and prognosis of DRCO were worse.

2.
Sci Total Environ ; 905: 166971, 2023 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-37699477

RESUMEN

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic chemicals that occur ubiquitously in the environment and have been linked to numerous adverse health effects in humans and aquatic organisms. Although numerous environmental monitoring studies have been conducted, only one has evaluated PFAS in surface waters of the northwestern Great Basin, which features unique topography that results in dozens of endorheic basins and terminal lakes with no natural outlet, where PFAS may accumulate. To close this knowledge gap, we evaluated the occurrence of PFAS in grab samples from 15 lakes (headwater and terminal lakes) and 10 rivers in the Great Basin located in Nevada and California of the United States. PFAS and organofluorine were quantified by liquid chromatography tandem mass spectroscopy (LC-MS/MS) and combustion ion chromatography, respectively. The highest concentrations of PFAS occurred in samples taken near sites with known or suspected prior aqueous film forming foam (AFFF) application (~20 to 4754 ng/L). Samples near wastewater treatment plants and in urban areas also tended to have PFAS concentrations greater than those measured in remote, less anthropogenically influenced areas (~2 to 15 ng/L, <3 ng/L respectively). In limited snapshot sampling events PFAS appeared to accumulate in terminal lakes to some extent; in-lake concentrations were two to five times greater than those of their inflows. Fluorotelomer sulfonates were present downstream of a known AFFF application area likely to have had fluorotelomer-based foams applied to it, and the concentrations decayed in a predictable manner, suggesting they may be used as an indicator of PFAS transport away from an AFFF source. In all but two samples, organofluorine concentrations were greater than the sum of targeted PFAS (on a F basis) (median of 0.6 % of organofluorine identified via LC-MS/MS), although there was considerable variability in organofluorine measured in replicate samples.

3.
Int Immunopharmacol ; 119: 110153, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37071966

RESUMEN

Currently, there is no effective therapy for Staphylococcus aureus-induced osteomyelitis. It is widely recognized that the inflammatory microenvironment around abscess plays an essential role in protracting the course of S. aureus-induced osteomyelitis. In this study, we found TWIST1 was highly expressed in macrophages around abscesses but less related to local S. aureus in the later stages of Staphylococcus aureus-infected osteomyelitis. Mouse bone marrow macrophages show apoptosis and elevated TWIST1 expression when treated with the inflammatory medium. Knockdown of TWIST1 induced macrophage apoptosis, impaired the bacteria phagocytosis/killing abilities, and promoted cell apoptosis markers expression in inflammatory microenvironment stimulation. Furthermore, inflammatory microenvironments were responsible for inducing calcium overload in macrophage mitochondrial while calcium overload inhibition significantly rescued macrophage apoptosis, bacteria phagocytosis/killing abilities and improved the mice's antimicrobial ability. Our findings indicated that TWIST1 is a crucial molecule that protects macrophages from calcium overload induced by inflammatory microenvironments.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Osteomielitis , Infecciones Estafilocócicas , Animales , Ratones , Staphylococcus aureus , Calcio , Osteomielitis/metabolismo , Osteomielitis/microbiología , Infecciones Estafilocócicas/metabolismo , Apoptosis , Bacterias
4.
Environ Sci Technol ; 57(15): 6179-6187, 2023 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-37018767

RESUMEN

The thermal decomposition products and mechanisms of per- and polyfluoroalkyl substances (PFASs) are poorly understood despite the use of thermal treatment to remediate PFAS-contaminated media. To identify the thermal decomposition products and mechanisms of perfluorocarboxylic acids (PFCAs), gaseous perfluoropropionic acid (PFPrA) and perfluorobutyric acid (PFBA) were decomposed in nitrogen and oxygen at temperatures from 200 to 780 °C. In nitrogen (i.e., pyrolysis), the primary products of PFPrA were CF2═CF2, CF3CF2H, and CF3COF. CF3CF═CF2 was the dominant product of PFBA. These products are produced by HF elimination (detected as low as 200 °C). CF4 and C2F6 were observed from both PFCAs, suggesting formation of perfluorocarbon radical intermediates. Pyrolysis products were highly thermally stable, resulting in poor defluorination. In oxygen (i.e., combustion), the primary product of both PFPrA and PFBA below 400 °C was COF2, but the primary product was SiF4 above 600 °C due to reactions with the quartz reactor. Oxygen facilitated thermal defluorination by reacting with PFCAs and with pyrolysis products (i.e., fluoroolefins and fluorocarbon radicals). Platinum improved combustion of PFCAs to COF2 at temperatures as low as 200 °C, while quartz promoted the combustion of PFCAs into SiF4 at higher temperatures (>600 °C), highlighting the importance of surface reactions that are not typically incorporated into computational approaches.


Asunto(s)
Fluorocarburos , Contaminantes Químicos del Agua , Gases , Cuarzo , Fluorocarburos/análisis , Oxígeno , Nitrógeno
5.
J Affect Disord ; 332: 72-82, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-36997126

RESUMEN

BACKGROUND: N-methyl-d-aspartate receptor (NMDAR) has been implicated in the pathophysiology of depression. However, as the unique inhibitory subunit of NMDARs, the role of GluN3A in depression is largely unclear. METHODS: Firstly, expression of GluN3A was examined in a mouse model of depression induced by chronic restraint stress (CRS). Then, rescue experiment with rAAV-Grin3a injection into hippocampus of CRS mice was carried out. Lastly, GluN3A knockout (KO) mouse was generated via CRISPR/Cas9 technique, and the molecular mechanism underlying involvement of GluN3A in depression was initially explored using RNA-seq technique, RT-PCR and western blotting. RESULTS: GluN3A expression in hippocampus was significantly decreased in CRS mice. Depression-like behaviors induced by CRS were ameliorated when the decrease of GluN3A expression in mice exposed to CRS was restored. GluN3A KO mice exhibited symptoms of anhedonia reported as reduced sucrose preference, and symptoms of despair assayed by a longer immobility time in FST. Transcriptome analysis revealed genetic ablation of GluN3A was associated with downregulation of genes implicated in synapse and axon development. Postsynaptic protein PSD95 was decreased in GluN3A KO mice. More importantly, reduction of PSD95 in CRS mice can be rescued by viral mediated Grin3a re-expression. LIMITATIONS: The mechanism underlying GluN3A involvement in depression is not fully determined. CONCLUSIONS: Our data suggested that GluN3A dysfunction is involved in depression, which might be mediated by synaptic deficits. These findings will facilitate the understanding of the role of GluN3A in depression, and they might provide a new strategy for the development of subunit-selective NMDAR antagonists as antidepressant drugs.


Asunto(s)
Depresión , Sinapsis , Ratones , Animales , Depresión/genética , Ratones Noqueados , Hipocampo/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo
6.
Front Cell Dev Biol ; 10: 1054365, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36568987

RESUMEN

Objective: There is very limited evidence in the NHANES database linking serum apolipoprotein B and lumbar bone mineral density (BMD) in adults aged 20-59 years. There are few studies associating apolipoprotein B concentrations with BMD, and there is some debate about the association between obesity and BMD. Therefore, the purpose of this study was to determine the association between serum apolipoprotein B concentrations and lumbar spine BMD in adults aged 20-59 years and to predict its association with risk of osteopenia or osteoporosis. Methods: A cross-sectional study of the entire US ambulatory population was conducted using data from the National Health and Nutrition Examination Survey (NHANES) database. Weighted multiple regression equation models were used to assess the association between serum apolipoprotein B and lumbar BMD. A logistic weighted regression model was used to assess the association between serum apolipoprotein B concentrations and risk of osteopenia or osteoporosis. Subsequent stratified analyses were performed to refine the primary population of association. Results: Our study showed a significant negative association between serum apolipoprotein B concentration and lumbar BMD and a significant positive association with the risk of osteoporosis or osteopenia in the total population. After stratifying by sex, age and race, we concluded differently. The association of serum apolipoprotein B concentration with lumbar spine BMD and risk of osteopenia or osteoporosis was significant in male, but not in female. After stratification by age, the negative association between serum apolipoprotein B concentrations and lumbar BMD and the positive association with risk of osteopenia or osteoporosis was more significant in the 30-39 and 50-59 years age groups. When stratified by race, serum apolipoprotein B concentrations were significantly negatively associated with lumbar BMD and positively associated with risk of osteopenia or osteoporosis in Mexican American and non-Hispanic black populations. Thus, these findings suggest that these associations are influenced by sex, age, and race, respectively. Conclusion: Our results suggest that the association between serum apolipoprotein B levels and the risk of lumbar BMD and osteopenia or osteoporosis varies by sex, age, and race. In men, elevated serum apolipoprotein B levels were negative for bone quality. Elevated serum apolipoprotein B levels in the age groups 30-39 and 50-59 years also had a negative effect on bone quality. In the Mexican American and Non-Hispanic Black populations, elevated serum apolipoprotein B levels also had a significant negative effect on bone quality.

7.
Front Microbiol ; 13: 1029261, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36406460

RESUMEN

Growing evidence has shown that the efficacy of systemic administration of daptomycin for the treatment of methicillin-resistant Staphylococcus aureus (MRSA)-related infections is satisfactory. However, the clinical efficacy of the local administration of daptomycin for the management of osteoarticular infections remains unclear. This in vitro study compared the efficacy of daptomycin and vancomycin against MRSA biofilms. The elution kinetics of daptomycin and vancomycin, combined with gentamicin and loaded with either ß-tricalcium phosphate/calcium sulfate or calcium sulfate, in the presence of MRSA infection, was assessed. Their efficacy in preventing biofilm formation and killing pre-formed biofilms was assessed using colony-forming unit count and confocal laser scanning microscopy. In addition, the efficacy of daptomycin, vancomycin, and gentamicin in prophylaxis and eradication of MRSA biofilms was also evaluated. Daptomycin + gentamicin and vancomycin + gentamicin displayed similar antimicrobial potency against MRSA, by either ß-tricalcium phosphate/calcium sulfate or calcium sulfate. In the prevention assays, both daptomycin + gentamicin and vancomycin + gentamicin showed similar efficacy in preventing bacterial colony formation, with approximately 6 logs lower colony-forming units than those in the control group at both 1 and 3 days. The killing effect on pre-formed biofilms showed significant decreases of approximately 4 logs at 1 and 3 days following treatment with daptomycin + gentamicin and vancomycin + gentamicin. In addition, the confocal laser scanning microscopy results support the colony-forming unit data. Moreover, single use of vancomycin and gentamicin showed similar efficacies in preventing and killing MRSA biofilms, both of which were better than that of gentamicin. Our study demonstrated that vancomycin + gentamicin and daptomycin + gentamicin loaded with ß-tricalcium phosphate/calcium sulfate or calcium sulfate showed similar prophylactic and killing effects on MRSA biofilms, implying a potential indication of local administration daptomycin for the treatment of MRSA-associated osteoarticular infections, especially if vancomycin administration presents limitations.

8.
Stem Cells Int ; 2022: 9359429, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36277036

RESUMEN

Current research suggests that chronic high-fat dietary intake can lead to bone loss in adults; however, the mechanism by which high-fat diets affect the development of osteoporosis in individuals is unclear. As high-fat diets are strongly associated with ferroptosis, whether ferroptosis mediates high-fat diet-induced bone loss was the focus of our current study. By dividing the mice into a high-fat diet group, a high-fat diet + ferroptosis inhibitor group and a normal chow group, mice in the high-fat group were given a high-fat diet for 12 weeks. The mice in the high-fat diet + ferroptosis inhibitor group were given 1 mg/kg Fer-1 per day intraperitoneally at the start of the high-fat diet. Microscopic CT scans, histological tests, and biochemical indicators of ferroptosis were performed on bone tissue from all three groups at the end of the modelling period. Mc3t3-E1 cells were also used in vitro and divided into three groups: high-fat medium group, high-fat medium+ferroptosis inhibitor group, and control group. After 24 hours of incubation in high-fat medium, Mc3t3-E1 cells were assayed for ferroptosis marker proteins and biochemical parameters, and osteogenesis induction was performed simultaneously. Cellular alkaline phosphatase content and expression of osteogenesis-related proteins were measured at day 7 of osteogenesis induction. The results showed that a high-fat diet led to the development of femoral bone loss in mice and that this process could be inhibited by ferroptosis inhibitors. The high-fat diet mainly affected the number of osteoblasts produced in the bone marrow cavity. The high-fat environment in vitro inhibited osteoblast proliferation and osteogenic differentiation, and significant changes in ferroptosis-related biochemical parameters were observed. These findings have implications for the future clinical treatment of bone loss caused by high-fat diets.

9.
Chaos ; 32(6): 063115, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35778117

RESUMEN

Reaction-diffusion processes organized in networks have attracted much interest in recent years due to their applications across a wide range of disciplines. As one type of most studied solutions of reaction-diffusion systems, patterns broadly exist and are observed from nature to human society. So far, the theory of pattern formation has made significant advances, among which a novel class of instability, presented as wave patterns, has been found in directed networks. Such wave patterns have been proved fruitful but significantly affected by the underlying network topology, and even small topological perturbations can destroy the patterns. Therefore, methods that can eliminate the influence of network topology changes on wave patterns are needed but remain uncharted. Here, we propose an optimal control framework to steer the system generating target wave patterns regardless of the topological disturbances. Taking the Brusselator model, a widely investigated reaction-diffusion model, as an example, numerical experiments demonstrate our framework's effectiveness and robustness. Moreover, our framework is generally applicable, with minor adjustments, to other systems that differential equations can depict.


Asunto(s)
Difusión , Humanos
10.
Environ Sci Technol ; 56(9): 5355-5370, 2022 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-35446563

RESUMEN

Per- and polyfluoroalkyl substances (PFASs) are fluorinated organic chemicals that are concerning due to their environmental persistence and adverse human and ecological effects. Remediation of environmental PFAS contamination and their presence in consumer products have led to the production of solid and liquid waste streams containing high concentrations of PFASs, which require efficient and cost-effective treatment solutions. PFASs are challenging to defluorinate by conventional and advanced destructive treatment processes, and physical separation processes produce waste streams (e.g., membrane concentrate, spent activated carbon) requiring further post-treatment. Incineration and other thermal treatment processes are widely available, but their use in managing PFAS-containing wastes remains poorly understood. Under specific operating conditions, thermal treatment is expected to mineralize PFASs, but the degradation mechanisms and pathways are unknown. In this review, we critically evaluate the thermal decomposition mechanisms, pathways, and byproducts of PFASs that are crucial to the design and operation of thermal treatment processes. We highlight the analytical capabilities and challenges and identify research gaps which limit the current understanding of safely applying thermal treatment to destroy PFASs as a viable end-of-life treatment process.


Asunto(s)
Fluorocarburos , Contaminantes Químicos del Agua , Carbón Orgánico , Fluorocarburos/análisis , Humanos , Incineración , Contaminantes Químicos del Agua/análisis
11.
Front Cell Dev Biol ; 10: 841612, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35223858

RESUMEN

As the population of most nations have a large proportion of older individuals, there is an increase in the prevalence of osteoporosis. Consequently, scientists have focused their attention on the pathogenic mechanisms of osteoporosis. Owing to an increase in studies on cellular senescence in recent years, research has begun to focus on the function of the senescent microenvironment in osteoporosis. With chronic inflammation, senescent cells in the bone marrow secrete a series of factors known as senescence-associated secretory phenotype (SASP) factors, acting on their own or surrounding healthy cells and consequently exacerbating ageing.The components of the SASP may differ depending on the cause of osteoporosis. This review aimed to summarize the relationship between SASP factors and osteoporosis and suggest new insights into the mechanistic investigation of osteoporosis.

12.
Front Psychol ; 12: 790727, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34987453

RESUMEN

With the development of Internet e-commerce channels, online shopping platforms have become the main channel for consumers to buy nearly expired food. Date labels, as one of the main external clues, play a decisive role in nearly expired food purchasing. Therefore, based on attention-related theory, this study attempts to explore the influence exerted by different time frames on consumers' willingness to buy and its mechanism. The results show that compared with the date, consumers have a higher willingness to buy nearly expired food when the expiration time is framed by delay. More specifically, compared to the date, the delay causes the individual to have a longer time perception, thus more preference for nearly expired food. Meanwhile, the mediating effect of time perception is moderated by food type. The conclusion of this research is helpful to expand the theoretical framework of time frames and related fields on nearly expired food, as well as provide practical guidance for marketers to effectively promote nearly expired food.

13.
PeerJ ; 8: e9484, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32742785

RESUMEN

BACKGROUND: Bone marrow adipocyte (BMA), closely associated with bone degeneration, shares common progenitors with osteoblastic lineage. However, the intrinsic mechanism of cells fate commitment between BMA and osteogenic lineage remains unclear. METHODS: Gene Expression Omnibus (GEO) dataset GSE107789 publicly available was downloaded and analyzed. Differentially expressed genes (DEGs) were analyzed using GEO2R. Functional and pathway enrichment analyses of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were conducted by The Database for Annotation, Visualization and Integrated Discovery and Gene set enrichment analysis software. Protein-protein interactions (PPI) network was obtained using STRING database, visualized and clustered by Cytoscape software. Transcriptional levels of key genes were verified by real-time quantitative PCR in vitro in Bone marrow stromal cells (BMSCs) undergoing adipogenic differentiation at day 7 and in vivo in ovariectomized mice model. RESULTS: A total of 2,869 DEGs, including 1,357 up-regulated and 1,512 down-regulated ones, were screened out from transcriptional profile of human BMSCs undergoing adipogenic induction at day 7 vs. day 0. Functional and pathway enrichment analysis, combined with modules analysis of PPI network, highlighted ACSL1, sphingosine 1-phosphate receptors 3 (S1PR3), ZBTB16 and glypican 3 as key genes up-regulated at the early stage of BMSCs adipogenic differentiation. Furthermore, up-regulated mRNA expression levels of ACSL1, S1PR3 and ZBTB16 were confirmed both in vitro and in vivo. CONCLUSION: ACSL1, S1PR3 and ZBTB16 may play crucial roles in early regulation of BMSCs adipogenic differentiation.

14.
J Alzheimers Dis ; 71(3): 825-832, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31450504

RESUMEN

Administration of sevoflurane (SEVO) may induce learning and memory deficits, which increases the chances of developing Alzheimer's disease. Here, we studied the effects of SEVO exposure on rats with a focus on the role of insulin-like growth factor (IGF) signaling. SEVO exposure significantly increased neuron cell apoptosis, and caused poor performance of the rats in behavior tests, by suppressing IGF-1 receptor (IGF1R). Bioinformatic analysis predicted microRNA(miR)-223-3p as an IGF1R-binding miRNA, the level of which increased in neurons after exposure to SEVO. In vitro, miR-223-3p suppressed the translation of IGF1R in neural cells. Moreover, transfection with antisense of miR-223-3p significantly attenuated SEVO exposure-induced neuron cell apoptosis. Taken together, these data suggest that SEVO-induced miR-223-3p upregulation suppresses IGF1R to impair IGF signaling, which subsequently leads to learning and memory impairments.


Asunto(s)
Anestésicos por Inhalación/efectos adversos , Trastornos de la Memoria/inducido químicamente , Memoria/efectos de los fármacos , Receptor IGF Tipo 1/efectos de los fármacos , Sevoflurano/efectos adversos , Animales , Apoptosis/efectos de los fármacos , Biología Computacional , Femenino , Aprendizaje por Laberinto/efectos de los fármacos , Trastornos de la Memoria/psicología , MicroARNs/genética , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Desempeño Psicomotor/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Regulación hacia Arriba
15.
Water Res ; 145: 579-587, 2018 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-30199802

RESUMEN

Adsorbable organic halogen (AOX) is a parameter conventionally used to indicate the sum of organic halogenated disinfection byproducts (DBPs), which are formed from the reactions of disinfectants with dissolved organic matter, bromide and iodide in water. To overcome the issues of the AOX analytical method, we proposed a new facile and green pretreatment method to enable the analysis of nonionic total organic halogen (NTOX) via the following three steps: 1) separation of NTOX and halides with electrodialysis, 2) conversion of NTOX with ultraviolet (UV) photolysis, and 3) analysis of halides with ion chromatography. To verify this proposal, we mainly evaluated the efficiency of vacuum ultraviolet (VUV) coupled with UV photolysis (VUV-UV) in converting NTOX into halides. Results showed that by applying VUV irradiation for 60 min and UV irradiation at pH 10-11 for another 30 min, over 85.5% of each halide from 20 representative small molecular weight DBPs (each at 100 µg-X/L level) was recovered. The purpose of UV photolysis under alkaline conditions was to reduce oxyhalides (such as bromate and iodate) formed in the VUV process back to halides. With the aid of electrospray ionization-triple quadrupole mass spectrometry, we captured the whole pictures of high molecular weight polar DBPs in a chlorinated drinking water before and after VUV-UV, through which averagely 96.4% of dehalogenation with the VUV-UV treatment was observed. An illustrative comparison of the conventional AOX method and the proposed NTOX method indicates that although the detected NTOX was lower (by 2.3-30.6%) than AOX, the results of the two methods were highly correlated (R2 > 0.97). All these hence verified the photolysis as a mature yet novel tool for sample pretreatment in environmental analytical chemistry.


Asunto(s)
Desinfectantes , Contaminantes Químicos del Agua , Purificación del Agua , Desinfección , Halogenación , Halógenos , Fotólisis , Agua
16.
Anal Chem ; 89(21): 11537-11544, 2017 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-28737927

RESUMEN

Hydrogen peroxide (H2O2) is ubiquitous in the natural environment, and it is now widely used for pollutant control in water and wastewater treatment processes. However, current analytical methods for H2O2 inevitably require reactions between H2O2 and other reactants to yield signals and are thus likely subjective to the interferences of coexisting colored, oxidative, and reductive compounds. In order to overcome these barriers, we herein for the first time propose to analyze H2O2 by ion chromatography (IC) using an ultraviolet (UV) detector. The proposal is based on two principles: first, that H2O2 can deprotonate to hydroperoxyl ion (HO2-) when eluent pH is higher than the acid-dissociation coefficient of H2O2 (pKa = 11.6); and second, that after separation from other compounds via IC column, H2O2 can be quantified by a UV detector. Under favorable operating conditions, this method has successfully achieved acceptable recoveries (>91%) of H2O2 dosed to ultrapure and natural waters, a calibration curve with R2 > 0.99 for a wide range of H2O2 concentrations from 0.1 to 50 mg/L and a method detection limit of 0.027 mg/L. In addition, this approach was shown to be capable of distinguishing H2O2 from anions (e.g., fluoride and chloride) and organics (e.g., glycolate) and monochloramine, suggesting that it is insensitive to many neighboring compounds as long as they do not react quickly with H2O2. Hence, this study proves the combination of IC and UV detector a facile and reliable method for H2O2 measurement.

17.
Chemosphere ; 184: 1003-1011, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28658735

RESUMEN

In order to achieve better removal and analyses of three dissolved inorganic nitrogen (DIN) species via ultraviolet-activated hydrogen peroxide (UV/H2O2) process, this study systematically investigated the rates of photo-oxidations of ammonia/ammonium (NH3/NH4+) and nitrite (NO2-) as well as the photo-reduction of nitrate (NO3-) at varying pH and H2O2 conditions. The results showed that the mass balances of nitrogen were maintained along irradiation despite of interconversions of DIN species, suggesting that no nitrogen gas (N2) or other nitrogen-containing compound was formed. NH3 was more reactive than NH4+ with hydroxyl radical (OH), and by a stepwise H2O2 addition method NH3/NH4+ can be completely converted to NOx-; NO2- underwent rapid oxidation to form NO3- when H2O2 was present, suggesting that it is an intermediate compound linking NH3/NH4+ and NO3-; but once H2O2 was depleted, NO3- can be gradually photo-reduced back to NO2- at high pH conditions. Other than H2O2, the transformation kinetics of DINs were all dependent on pH, but to varying aspects and extents: the NH3 photo-oxidation favored a pH of 10.3, which fell within the pKa values of NH4+ (9.24) and H2O2 (11.6); the NO3- photo-reduction increased with increasing pH provided that it exceeds the pKa of peroxynitrous acid (6.8); while the NO2- photo-oxidation remained stable unless the pH neared the pKa of H2O2 (11.6). The study thereby demonstrates a picture of the evolutions of DIN species together during UV/H2O2 irradiation process, and for the first time presents a method to achieve complete conversion of NH4+ to NO3- with UV/H2O2 process.


Asunto(s)
Amoníaco/química , Peróxido de Hidrógeno/química , Nitratos/química , Nitritos/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Compuestos de Amonio , Desnitrificación , Concentración de Iones de Hidrógeno , Radical Hidroxilo , Cinética , Nitrógeno , Óxidos de Nitrógeno , Oxidación-Reducción , Rayos Ultravioleta
18.
Eur Neurol ; 75(5-6): 251-6, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27174085

RESUMEN

BACKGROUND/AIMS: It is crucial to detect the composition of the thrombus in isolated brainstem infarction with large artery occlusion. The aim of this study was to explore the susceptibility vessel sign (SVS) whose composition is mainly deoxidized red cells in patients with isolated brainstem infarction and posterior circulation large artery occlusion. METHODS: This was a single-center retrospective study. All patients with posterior circulation large artery occlusion from January 2003 to September 2013 were included. We identified 213 patients who had posterior circulation large artery occlusion, and 81 patients met the imaging eligibility criteria. Among the 81 patients, 21 had isolated brainstem infarction. RESULTS: Among the 21 patients, 7 (33%) had SVS and 2 (10%) had pseudo-SVS (calcified vessels without thrombosis). In the 7 patients with SVS, we found atrial fibrillation in 2 patients, dissection in 3 patients and large artery atherosclerotic disease (LAAD) in 2 patients. There were SVS in 100% (2/2) of patients with atrial fibrillation, 50% (3/6) of patients with dissection, and 20% (2/10) of patients with LAAD. CONCLUSIONS: SVS reflects pathology of deoxidized red cells composition in patients with isolated brainstem infarction. This finding may be useful to explore the different stroke mechanisms and therapy strategies.


Asunto(s)
Arteriopatías Oclusivas/patología , Infartos del Tronco Encefálico/patología , Eritrocitos/patología , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
19.
J Neurochem ; 136(6): 1186-1195, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26718749

RESUMEN

Fluoxetine has become one of the most promising drugs for improving clinical outcome in patients with cerebral infarction. Although the clinical efficacy of fluoxetine has been preliminarily demonstrated, its mechanism remains unclear. Hypoxia-inducible factor 1-alpha (HIF-1α) is upstream to Netrin and vascular endothelial growth factor (VEGF), and under hypoxia conditions it may induce expression of Netrin-1 and VEGF in vascular endothelial cells. We sought to explore whether it can regulate their expression in hypoxia and mediate the effect of fluoxetine in hypoxia. In this study, the effect of hypoxia on the expression of VEGF and Netrin was observed in vitro by real-time PCR and western blotting in SH-SY5Y cells; the binding sites of HIF-1α in VEGF and Netrin gene promoters were identified by luciferase reporter; the effect of fluoxetine on binding of HIF-1α with Netrin and VEGF promoters in hypoxia was observed by Chromatin Immunoprecipitation (ChIP) Assay. We prove that HIF-1α regulates transcription of both VEGF and Netrin, and that in hypoxia fluoxetine up-regulates VEGF and Netrin expression via mediation of HIF-1α that binds to hypoxia-response element sites of VEGF and Netrin promoters. Our study indicates that HIF-1α may play an important role in the treatment of cerebral infarction through mediating the recovery of neurological function induced by fluoxetine, which provides theoretical basis for the development of gene therapeutic drugs targeting HIF-1α. We show that hypoxia-inducible factor 1-alpha (HIF-1α) regulates transcription of both vascular endothelial growth factor (VEGF) and Netrin. Furthermore, we also show that in hypoxia fluoxetine up-regulates VEGF and Netrin expression via mediation of HIF-1α that binds to hypoxia-response element (HRE) sites of VEGF and Netrin promoters. Our study indicates that HIF-1α may play an important role in the treatment of cerebral infarction through mediating the recovery of neurological function induced by fluoxetine. These findings provide a theoretical basis for development of gene therapeutic drugs targeting HIF-1α.

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