Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Immunity ; 57(5): 1071-1086.e7, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38677291

RESUMO

Following tissue damage, epithelial stem cells (SCs) are mobilized to enter the wound, where they confront harsh inflammatory environments that can impede their ability to repair the injury. Here, we investigated the mechanisms that protect skin SCs within this inflammatory environment. Characterization of gene expression profiles of hair follicle SCs (HFSCs) that migrated into the wound site revealed activation of an immune-modulatory program, including expression of CD80, major histocompatibility complex class II (MHCII), and CXC motif chemokine ligand 5 (CXCL5). Deletion of CD80 in HFSCs impaired re-epithelialization, reduced accumulation of peripherally generated Treg (pTreg) cells, and increased infiltration of neutrophils in wounded skin. Importantly, similar wound healing defects were also observed in mice lacking pTreg cells. Our findings suggest that upon skin injury, HFSCs establish a temporary protective network by promoting local expansion of Treg cells, thereby enabling re-epithelialization while still kindling inflammation outside this niche until the barrier is restored.


Assuntos
Antígeno B7-1 , Folículo Piloso , Inflamação , Pele , Células-Tronco , Linfócitos T Reguladores , Cicatrização , Animais , Linfócitos T Reguladores/imunologia , Camundongos , Cicatrização/imunologia , Pele/imunologia , Pele/lesões , Pele/patologia , Células-Tronco/imunologia , Células-Tronco/metabolismo , Inflamação/imunologia , Folículo Piloso/imunologia , Antígeno B7-1/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reepitelização/imunologia , Movimento Celular/imunologia , Proliferação de Células
3.
Inorg Chem ; 60(5): 3139-3148, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33576608

RESUMO

The complexation of cerium with glutarimidedioxime (H2L) was studied by potentiometry, ESI-mass spectrometry, and cyclic voltammetry. Crystallization of [CeIV(HL)3]+ from Ce3+ starting reactant indicated spontaneous complexation-driven oxidation. In aqueous solution, Ce3+ ions form three successive complexes, Ce(HL)2+, Ce(HL)2+, and Ce(HL)3 (where HL- stands for the singly deprotonated ligand). The interactions of glutarimidedioxime with metal ions are dominantly electrostatic in nature, and the stability constants of the complexes are correlated to the charge density of metal ions. Extrapolations of predicted stability constant (log ß) values were made from plotting effective charge and the ionic radius of the metal ion for Pu3+ and Pu4+. The stability constants of PuIV(HL)3+ and PuIII(HL)2+ are estimated to be 27.74 and 19.75, respectively. The differences of stability constants mean that glutarimidedioxime selectively binds Pu4+ over Pu3+ by a factor of about 8 orders of magnitude, suggesting Pu4+ would be stabilized by chelation with glutarimidedioxime. The mechanism of reduction of Pu4+ to Pu3+ in acidic solution is explained by decomposition of glutarimidedioxime through acid hydrolysis rather than a chelation-driven mechanism.

4.
BMC Urol ; 20(1): 32, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32197612

RESUMO

BACKGROUND: There is no consensus between urologists on the diagnosis and treatment of female urethral diverticula. Once the diagnosis has been established, the most common treatment approach is surgical excision and reconstruction. Whether a staged procedure or simultaneous management is more appropriate for treating concomitant urethral diverticula and stress urinary incontinence remains controversial. CASE PRESENTATION: A 63-year-old woman was hospitalized for repeated frequent urination, urgent urination, odynuria, and dysuria accompanied by intermittent overflow urinary incontinence for over 10 years. She had a 5 year history of urinary stress incontinence prior to onset of these symptoms and had had four urethral caruncles resected on four separate occasions. There was visible leakage of urine when abdominal pressure was increased during physical examination and urodynamic studies. Additionally, turbid urine was discharged when the anterior vaginal wall was squeezed. Cystourethrography showed circumferential filling with contrast and multiple bladder diverticulae in the mid plane of the pubic symphysis. Urethrocystoscopy showed an orifice to a diverticulum at 7 o'clock in the proximal urethra, into which an F19.8 urethroscope could be inserted, enabling examination of most of the diverticulae. The urethral diverticulae were resected, followed by mesh reconstruction of the urethra. During a 20-month follow-up, the treatment outcomes were satisfactory. CONCLUSION: We here report a case of a giant circumferential urethral diverticulum combined with stress urinary incontinence that was successfully managed by an uncommon surgical reconstructive technique: a minimally invasive "Sandwich" mesh repair procedure utilizing synthetic mesh wrap in the midurethral region.


Assuntos
Divertículo/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Telas Cirúrgicas , Doenças Uretrais/cirurgia , Procedimentos Cirúrgicos Urológicos/métodos , Divertículo/complicações , Divertículo/fisiopatologia , Disuria/etiologia , Disuria/fisiopatologia , Endoscopia , Feminino , Humanos , Pessoa de Meia-Idade , Doenças Uretrais/complicações , Doenças Uretrais/fisiopatologia , Incontinência Urinária/etiologia , Incontinência Urinária/fisiopatologia
5.
Science ; 367(6480): 875-881, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32001526

RESUMO

Mammalian SWI/SNF family chromatin remodelers, BRG1/BRM-associated factor (BAF) and polybromo-associated BAF (PBAF), regulate chromatin structure and transcription, and their mutations are linked to cancers. The 3.7-angstrom-resolution cryo-electron microscopy structure of human BAF bound to the nucleosome reveals that the nucleosome is sandwiched by the base and the adenosine triphosphatase (ATPase) modules, which are bridged by the actin-related protein (ARP) module. The ATPase motor is positioned proximal to nucleosomal DNA and, upon ATP hydrolysis, engages with and pumps DNA along the nucleosome. The C-terminal α helix of SMARCB1, enriched in positively charged residues frequently mutated in cancers, mediates interactions with an acidic patch of the nucleosome. AT-rich interactive domain-containing protein 1A (ARID1A) and the SWI/SNF complex subunit SMARCC serve as a structural core and scaffold in the base module organization, respectively. Our study provides structural insights into subunit organization and nucleosome recognition of human BAF complex.


Assuntos
Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona/química , DNA Helicases/química , Proteínas Nucleares/química , Nucleossomos/química , Proteína SMARCB1/química , Fatores de Transcrição/química , Adenosina Trifosfatases/química , Trifosfato de Adenosina/metabolismo , Proteínas Cromossômicas não Histona/genética , Microscopia Crioeletrônica , Proteínas de Ligação a DNA , Humanos , Hidrólise , Mutação , Neoplasias/genética , Conformação Proteica em alfa-Hélice , Fatores de Transcrição/genética
6.
Inorg Chem ; 58(22): 15618-15628, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31674777

RESUMO

N-(2-Hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA, denoted as H3L) is a strong chelating ligand that is widely used in the separation of f elements as relevant to the nuclear fuel cycle. There is much to be known about the structure and composition of the coordination sphere of the complexes of HEDTA with lanthanides. The complexation of HEDTA with light lanthanides (La3+, Nd3+, and Eu3+) was investigated thermodynamically and structurally in aqueous solutions. Potentiometry and microcalorimetry were performed to acquire the complexation constants (25-70 °C) and enthalpies (25 °C), respectively, at I = 1.0 mol·L-1 NaClO4. Coordination modes of the complexes were analyzed by luminescence spectroscopy and NMR spectroscopy. The results indicate that there are two successive Ln3+/HEDTA complexes, LnLaq and Ln2(H-1L)22- (Ln3+ refers to La3+, Nd3+, and Eu3+; H-1L4- refers to deprotonation of the hydroxyl group) during titration. The hydroxyl group of HEDTA is coordinated in the Ln3+/HEDTA complex. The dinuclear Ln2(H-1L)22- complex is present as a carboxyl-bridged centrosymmetric dimer, and two carboxyl groups in bridging positions are coordinated to two adjacent Ln3+ cations. Complexation of NdLaq is exothermic, while formation of the hydrolytic complex Nd2(H-1L)22- is endothermic. Both NdLaq and Nd2(H-1L)22- complexes are driven by entropic force. These data will help to predict the behavior of lanthanides in the separation process, where HEDTA is used as the aqueous complexant.

7.
J Phys Chem B ; 120(9): 2132-7, 2016 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-26862689

RESUMO

Glyphosate [N-(phosphonomethyl)glycine] has been described as the ideal herbicide because of its unique properties. There is some conflicting information concerning the structures and conformations involved in the protonation process of glyphosate. Protonation may influence the chemical and physical properties of glyphosate, modifying its structure and the chemical processes in which it is involved. To better understand the species in solution associated with changes in pH, thermodynamic study (potentiometry, calorimetry and NMR spectroscopy) about the protonation pathway of glyphosate is performed. Experimental results confirmed that the order of successive protonation sites of totally deprotonated glyphosate is phosphonate oxygen, amino nitrogen, and finally carboxylate oxygen. This trend is in agreement with the most recent theoretical work in the literature on the subject (J. Phys. Chem. A 2015, 119, 5241-5249). The result is important because it confirms that the protonated site of glyphosate in pH range 7-8, is not on the amino but on the phosphonate group instead. This corrected information can improve the understanding of the glyphosate chemical and biochemical action.


Assuntos
Calorimetria/métodos , Glicina/análogos & derivados , Herbicidas/química , Espectroscopia de Ressonância Magnética/métodos , Potenciometria/métodos , Termodinâmica , Glicina/química , Prótons , Soluções/química , Água/química , Glifosato
8.
Chemosphere ; 141: 162-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26196406

RESUMO

Application of bioleaching process for metal recovery from electronic waste has received an increasing attention in recent years. In this work, a column bioleaching of copper from waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans has been investigated. After column bioleaching for 28d, the copper recovery reached at 94.8% from the starting materials contained 24.8% copper. Additionally, the concentration of Fe(3+) concentration varied significantly during bioleaching, which inevitably will influence the Cu oxidation, thus bioleaching process. Thus the variation in Fe(3+) concentration should be taken into consideration in the conventional kinetic models of bioleaching process. Experimental results show that the rate of copper dissolution is controlled by external diffusion rather than internal one because of the iron hydrolysis and formation of jarosite precipitates at the surface of the material. The kinetics of column bioleaching WPCBs remains unchanged because the size and morphology of precipitates are unaffected by maintaining the pH of solution at 2.25 level. In bioleaching process, the formation of jarosite precipitate can be prevented by adding dilute sulfuric acid and maintaining an acidic condition of the leaching medium. In such way, the Fe(2)(+)-Fe(3+) cycle process can kept going and create a favorable condition for Cu bioleaching. Our experimental results show that column Cu bioleaching from WPCBs by A. ferrooxidans is promising.


Assuntos
Acidithiobacillus/crescimento & desenvolvimento , Cobre/isolamento & purificação , Resíduo Eletrônico/análise , Compostos Férricos/análise , Sulfatos/análise , Cinética , Reciclagem
9.
J Biotechnol ; 173: 24-30, 2014 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-24445171

RESUMO

In this paper, H(+) consumption and metal recovery, during the process of bioleaching waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans (A. ferrooxidans), were discussed in detail. When the WPCBs concentration was 15g/L, Cu (96.8%), Zn (83.8%), and Al (75.4%) were recovered after 72h by A. ferrooxidans. Experimental results indicated that metal recovery rate was significantly influenced by acid. Based on experimental results, the kinetics of the H(+) consumption and metal recovery on bioleaching WPCBs were represented by reaction kinetic equations. The kinetic of H(+) consumption could be described by the second-order kinetic model. The metal recovery belongs to the second-order model with adding acid, which was changed to the shrinking core model with precipitate production.


Assuntos
Acidithiobacillus/metabolismo , Equipamentos e Provisões Elétricas/microbiologia , Hidrogênio/metabolismo , Metais/metabolismo , Alumínio/metabolismo , Biodegradação Ambiental , Cobre/metabolismo , Resíduos Industriais , Cinética , Zinco/metabolismo
10.
J Hazard Mater ; 264: 386-94, 2014 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-24316810

RESUMO

Hexagonal tungsten oxide (hex-WO3) has the potential to separate (137)Cs and (90)Sr from nuclear power plant or fission (99)Mo production waste. This study aims to increase the capacity of hex-WO3 to adsorb Sr(2+). Ta-doped hex-WO3 was synthesized by the hydrothermal treatment of sodium tungstate dihydrate and tantalum chloride in concentrated HCl, in the presence of ammonium sulfate. Incorporating Ta into the WO3 framework caused the interlayer spacing to expand, and the band gap to shift to higher energy. The Sr(2+) adsorption capacity of Ta-doped hex-WO3 was significantly higher than that of hex-WO3. Sr(2+) adsorption reached equilibrium within 2h in acidic solution. Maximum Sr(2+) removal occurred at pH 4. Sr(2+) uptake by hex-WO3 was described better by the Freundlich model than by the Langmuir model. Sr(2+) adsorption on hex-WO3 was spontaneous under the studied conditions.


Assuntos
Óxidos/química , Estrôncio/isolamento & purificação , Tantálio/química , Tungstênio/química , Adsorção , Modelos Químicos
11.
Sci Total Environ ; 409(18): 3344-51, 2011 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-21684578

RESUMO

Like arsenic (As), antimony (Sb) is known to be a genotoxic element in vitro and in vivo. Sb is now recognized as a global contaminant and has aroused the global concerns recently. However, knowledge is scarce concerning the transfer of Sb from the environment to humans and the related hazards to human health. In this pilot study, the health risk and main pathway of long-term human exposure to Sb and As for residents around Chinese Xikuangshan (XKS) Sb mine, the world's largest Sb mine, were evaluated by dietary exposure and hair accumulations survey. The concentrations and species of Sb and As in food samples (n=209) from three main categories and six subcategories, and in hair samples (n=89) were determined. Residents in the vicinity of XKS had an estimated dietary intake of Sb (554 µg/day) which was 1.5 times higher than the tolerable daily intake (TDI) (Sb, 360 µg/day), whereas their dietary intake of inorganic As (107 µg/day) was slightly lower than the provisional tolerable weekly intake (PTWI) of 15 µg/kg BW/week (equal to 129 µg As/day). Hair Sb and As concentrations (Sb, 15.7 mg/kg, DW; As, 3.99 mg/kg, DW) in XKS residents are both above the normal/toxic level. Rice, vegetables (especially leafy vegetable), drinking water, and meat/poultry were the dominant dietary intake sources of Sb for the residents. In contrast, rice was the uniquely dominant dietary intake source of As. Antimonate (Sb(V)) was the dominant Sb species in vegetables, drinking water and residents' hairs. This study highlighted the difference of exposure characteristics between Sb and As. The preliminary results suggested that dietary exposures to Sb, rather than As, was the dominant health risk to local residents. Nevertheless, the adverse effects of As levels on the health of residents still can not be ignored since the elevated As concentrations in human hair have reached the critical level for health risks. In addition, this pilot study did not consider the possible Sb and As combined effects.


Assuntos
Antimônio/metabolismo , Arsênio/metabolismo , Dieta/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/metabolismo , Adulto , Antimônio/análise , Arsênio/análise , Criança , Pré-Escolar , China , Laticínios/análise , Exposição Ambiental/análise , Poluentes Ambientais/análise , Feminino , Análise de Alimentos , Contaminação de Alimentos/estatística & dados numéricos , Cabelo/metabolismo , Humanos , Lactente , Masculino , Carne/análise , Pessoa de Meia-Idade , Mineração , Medição de Risco , Verduras , Abastecimento de Água/análise
12.
Sci Total Environ ; 408(16): 3403-10, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20452645

RESUMO

Antimony (Sb) has received increasing attention recently due to its toxicity and potential human carcinogenicity. In the present work, drinking water, fish and algae samples were collected from the Xikuangshan (XKS) Sb mine area in Hunan, China. Results show that serious Sb and moderate arsenic (As) contamination is present in the aquatic environment. The average Sb concentrations in water and fish were 53.6 + or - 46.7 microg L(-1) and 218 + or - 113 microg kg(-1) dry weight, respectively. The Sb concentration in drinking water exceeded both Chinese and WHO drinking water guidelines by 13 and 3 times, respectively. Antimony and As concentrations in water varied with seasons. Fish gills exhibited the highest Sb concentrations but the extent of accumulation varied with habitat. Antimony enrichment in fish was significantly lower than that of As and Hg.


Assuntos
Antimônio/análise , Arsênio/análise , Peixes/metabolismo , Mercúrio/análise , Mineração , Poluentes Químicos da Água/análise , Animais , Antimônio/metabolismo , Arsênio/metabolismo , China , Concentração de Íons de Hidrogênio , Mercúrio/metabolismo , Microscopia Eletrônica de Varredura , Difração de Raios X
13.
Huan Jing Ke Xue ; 30(3): 907-12, 2009 Mar 15.
Artigo em Chinês | MEDLINE | ID: mdl-19432349

RESUMO

The concentration levels of antimony, arsenic and mercury in human hair collected from Xikuangshan antimony mining area and Guiyang City were determined by hydride generation-atomic fluorescence spectrometry after having been digested by nitric acid and perchloric acid. The contents of Sb, As and Hg are 15.9, 4.21, 1.79 microg/g in the samples from Xikuangshan antimony mining area and 0.532, 0.280, 0.338 microg/g in the samples from Guiyang City respectively. The contents of Sb, As and Hg in human hair of Xikuangshan antimony area are much higher than those of Guiyang City. The independent-samples t-test shows that there are no marked differences in the contents of Sb and As between male and female hair samples from both Xikuangshan antimony mining area and Guiyang City (p > 0.05), while Hg contents in male hair are apparently higher than those in female hair from Guiyang City (p < or = 0.05). There is positive correlation observed between As and Sb, as well as between As and Hg, while Sb is weakly correlated with Hg (p < or = 0.01). These results show that the heavy metals (Sb, As and Hg) in antimony mining area may significantly affect human health than in the un-mining areas.


Assuntos
Antimônio/análise , Arsênio/análise , Cabelo/química , Mercúrio/análise , Mineração , China , Poluentes Ambientais/análise , Humanos , Espectrometria de Fluorescência/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...