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1.
Cytotherapy ; 26(5): 444-455, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38363248

RESUMO

BACKGROUND AIMS: Coronavirus disease 2019 (COVID-19) is characterized by a broad spectrum of clinical manifestations with the potential to progress to multiple organ dysfunction in severe cases. Extracellular vesicles (EVs) carry a range of biological cargoes, which may be used as biomarkers of disease state. METHODS: An exploratory secondary analysis of the SARITA-2 and SARITA-1 datasets (randomized clinical trials on patients with mild and moderate/severe COVID-19) was performed. Serum-derived EVs were used for proteomic analysis to identify enriched biological processes and key proteins, thus providing insights into differences in disease severity. Serum-derived EVs were separated from patients with COVID-19 by size exclusion chromatography and nanoparticle tracking analysis was used to determine particle concentration and diameter. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was performed to identify and quantify protein signatures. Bioinformatics and multivariate statistical analysis were applied to distinguish candidate proteins associated with disease severity (mild versus moderate/severe COVID-19). RESULTS: No differences were observed in terms of the concentration and diameter of enriched EVs between mild (n = 14) and moderate/severe (n = 30) COVID-19. A total of 414 proteins were found to be present in EVs, of which 360 were shared while 48 were uniquely present in severe/moderate compared to mild COVID-19. The main biological signatures in moderate/severe COVID-19 were associated with platelet degranulation, exocytosis, complement activation, immune effector activation, and humoral immune response. Von Willebrand factor, serum amyloid A-2 protein, histone H4 and H2A type 2-C, and fibrinogen ß-chain were the most differentially expressed proteins between severity groups. CONCLUSION: Exploratory proteomic analysis of serum-derived EVs from patients with COVID-19 detected key proteins related to immune response and activation of coagulation and complement pathways, which are associated with disease severity. Our data suggest that EV proteins may be relevant biomarkers of disease state and prognosis.


Assuntos
COVID-19 , Vesículas Extracelulares , Proteômica , SARS-CoV-2 , Índice de Gravidade de Doença , Humanos , COVID-19/sangue , COVID-19/diagnóstico , COVID-19/imunologia , Vesículas Extracelulares/metabolismo , Proteômica/métodos , Feminino , Masculino , Pessoa de Meia-Idade , Biomarcadores/sangue , Idoso , Adulto , Espectrometria de Massas em Tandem , Cromatografia Líquida
2.
An Acad Bras Cienc ; 94(suppl 3): e20210943, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35894375

RESUMO

Species distribution mapping methods have their advantages and limitations concerning their use on theoretical and/or applied macroecological approaches. However, it remains underexplored how the estimates of community ecology metrics vary across the distributions generated by different mapping methods. Here, we mapped the distribution patterns of the anuran beta diversity in the Atlantic Forest and Cerrado hotspots generated by three mapping methods: point-to-grid (PTG), extent-of-occurrence (EOO), and ecological niche modelling (ENM) maps, so we were able to compare the congruence of the local contribution to beta diversity index (LCBD) among them, as well as their turnover and nestedness components. PTGs generated the most divergent LCBD values probably due to the more resolved spatial scale in which species' presence are considered, so EEO and ENM generated similar beta diversity estimates for both hotspots. High LCBD values in the Cerrado were recorded in ecotone regions, whereas in the Atlantic Forest the highest beta diversity values were found along the Atlantic coast. The structure of beta diversity of PTG showed way too high values of importance for the turnover component compared to the EEO and ENM maps, which also recorded higher importance for the turnover than for the nestedness component.


Assuntos
Biodiversidade , Ecossistema , Animais , Anuros , Florestas
3.
J Org Chem ; 85(7): 4663-4671, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32155066

RESUMO

A density functional theory (DFT) computational analysis, using the ωB97X-D functional, of a rapid amide cleavage in 2-carboxyphthalanilic acid (2CPA), where the amide group is flanked by two catalytic carboxyls, reveals key mechanistic information: (a) General base catalysis by a carboxylate coupled to general acid catalysis by a carboxyl is not operative. (b) Nucleophilic attack by a carboxylate on the amide carbonyl coupled to general acid catalysis at the amide oxygen can also be ruled out. (c) A mechanistic pathway that remains viable involves general acid proton delivery to the amide nitrogen by a carboxyl, while the other carboxylate engages in nucleophilic attack upon the amide carbonyl; a substantially unchanged amide carbonyl in the transition state; two concurrent bond-forming events; and a spatiotemporal-base rate acceleration. This mechanism is supported by molecular dynamic simulations which confirm a persistent key intramolecular hydrogen bonding. These theoretical conclusions, although not easily verified by experiment, are consistent with a bell-shaped pH/rate profile but are at odds with hydrolysis mechanisms in the classic literature.

4.
Acc Chem Res ; 49(12): 2786-2795, 2016 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-27993006

RESUMO

Polymer networks are widely used from commodity to biomedical materials. The space-spanning, net-like structure gives polymer networks their advantageous mechanical and dynamic properties, the most essential factor that governs their responses to external electrical, thermal, and chemical stimuli. Despite the ubiquity of applications and a century of active research on these materials, the way that chemistry and processing interact to yield the final structure and the material properties of polymer networks is not fully understood, which leads to a number of classical challenges in the physical chemistry of gels. Fundamentally, it is not yet possible to quantitatively predict the mechanical response of a polymer network based on its chemical design, limiting our ability to understand and characterize the nanostructure of gels and rationally design new materials. In this Account, we summarize our recent theoretical and experimental approaches to study the physical chemistry of polymer networks. First, our understanding of the impact of molecular defects on topology and elasticity of polymer networks is discussed. By systematically incorporating the effects of different orders of loop structure, we develop a kinetic graph theory and real elastic network theory that bridge the chemical design, the network topology, and the mechanical properties of the gel. These theories show good agreement with the recent experimental data without any fitting parameters. Next, associative polymer gel dynamics is discussed, focusing on our evolving understanding of the effect of transient bonds on the mechanical response. Using forced Rayleigh scattering (FRS), we are able to probe diffusivity across a wide range of length and time scales in gels. A superdiffusive region is observed in different associative network systems, which can be captured by a two-state kinetic model. Further, the effects of the architecture and chemistry of polymer chains on gel nanostructure are studied. By incorporating shear-thinning coiled-coil protein motifs into the midblock of a micelle-forming block copolymer, we are able to responsively adjust the gel toughness through controlling the nanostructure. Finally, we review the development of novel application-oriented materials that emerge from our enhanced understanding of gel physical chemistry, including injectable gel hemostats designed to treat internal wounds and engineered nucleoporin-like polypeptide (NLP) hydrogels that act as biologically selective filters. We believe that the fundamental physical chemistry questions articulated in this Account will provide inspiration to fully understand the design of polymer networks, a group of mysterious yet critically important materials.


Assuntos
Materiais Biocompatíveis/química , Polímeros/química , Físico-Química , Cinética
5.
Angew Chem Int Ed Engl ; 56(19): 5345-5348, 2017 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-28378430

RESUMO

Aspartic proteinases, which include HIV-1 proteinase, function with two aspartate carboxy groups at the active site. This relationship has been modeled in a system possessing an otherwise unactivated amide positioned between two carboxy groups. The model amide is cleaved at an enzyme-like rate that renders the amide nonisolable at 35 °C and pH 4 owing to the joint presence of carboxy and carboxylate groups. A currently advanced theory attributing almost the entire catalytic power of enzymes to electrostatic reorganization is shown to be superfluous when suitable interatomic interactions are present. Our kinetic results are consistent with spatiotemporal concepts where embedding the amide group between two carboxylic moieties in proper geometries, at distances less than the diameter of water, leads to enzyme-like rate enhancements. Space and time are the essence of enzyme catalysis.


Assuntos
Amidas/metabolismo , Ácido Aspártico Proteases/metabolismo , Amidas/química , Ácido Aspártico Proteases/química , Biocatálise , Teoria da Densidade Funcional , Concentração de Íons de Hidrogênio , Cinética , Estrutura Molecular
6.
Crit Care ; 20(1): 323, 2016 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-27724931

RESUMO

BACKGROUND: The disproportion between the large organ demand and the low number of transplantations performed represents a serious public health problem worldwide. Reducing the loss of transplantable organs from deceased potential donors as a function of cardiac arrest (CA) may contribute to an increase in organ donations. Our purpose was to test the hypothesis that a goal-directed protocol to guide the management of deceased donors may reduce the losses of potential brain-dead donors (PBDDs) due to CA. METHODS: The quality improvement project included 27 hospitals that reported deceased donors prospectively to the Transplant Center of the State of Santa Catarina, Brazil. All deceased donors reported prospectively between May 2012 and April 2014 were analyzed. Hospitals were encouraged to use the VIP approach checklist during the management of PBDDs. The checklist was composed of the following goals: protocol duration 12-24 hours, temperature > 35 °C, mean arterial pressure ≥ 65 mmHg, diuresis 1-4 ml/kg/h, corticosteroids, vasopressin, tidal volume 6-8 ml/kg, positive end-expiratory pressure 8-10 cmH2O, sodium < 150 mEq/L, and glycemia < 180 mg/dl. A logistic regression model was used to identify predictors of CA. RESULTS: There were 726 PBDD notifications, of which 324 (44.6) were actual donors, 141 (19.4 %) CAs, 226 (31.1 %) family refusals, and 35 (4.8 %) contraindications. Factors associated with CA reduction included use of the checklist (odds ratio (OR) 0.43, p < 0.001), maintenance performed inside the ICU (OR 0.49, p = 0.013), and vasopressin administration (OR 0.56, p = 0.04). More than three interventions had association with less CAs (OR 0.19, p < 0.001). After 24 months, CAs decreased from 27.3 % to 14.6 % (p = 0.002), reaching 12.1 % in the following two 4-month periods (p < 0.001). Simultaneous increases in organ recovered per donor and in actual donors were observed. CONCLUSIONS: A quality improvement program based on education and the use of a goal checklist for the management of potential donors inside the ICU is strongly associated with a decrease in donor losses and an increase in organs recovered per donor.


Assuntos
Morte Encefálica , Tomada de Decisão Clínica/métodos , Objetivos , Parada Cardíaca/prevenção & controle , Doadores de Tecidos , Obtenção de Tecidos e Órgãos/normas , Adolescente , Adulto , Morte Encefálica/diagnóstico , Protocolos Clínicos , Parada Cardíaca/diagnóstico , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Melhoria de Qualidade/normas , Obtenção de Tecidos e Órgãos/métodos , Adulto Jovem
7.
Langmuir ; 31(12): 3587-95, 2015 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-25742026

RESUMO

This paper presents the physicochemical properties of micellar aggregates formed from a series of zwitterionic surfactants of the type 3-(1-alkyl-3-imidazolio)propane-sulfonate (ImS3-n), with n = 10, 12, 14, and 16. The ImS3-n dipolar ionic surfactants represent a versatile class of dipolar ionic compounds, which form normal and reverse micelles. Furthermore, they are able to stabilize nanoparticles in water and in organic media. Aqueous solubility is too low at room temperature to allow characterization of micellar aggregates but increases with addition of salts, allowing determination of aggregation number and cmc. As expected, these parameters depend on the length of the alkyl chain, and cmc values follow Klevens equation. In the presence of NaClO4, all ImS3-n micelles become anionoid by incorporating ClO4(-) on the micellar interface. A special feature of these surfactants is the ability to form reverse micelles and solubilize copious amounts of saline solutions in chloroform. (1)H NMR and infrared spectroscopic evidence showed that the maximum water to surfactant molar ratio w0 achievable depends on the concentration and type of salt dissolved. Reverse micelles of the ImS3-n surfactants can be used to stabilize metallic nanoparticles, whose size may be tuned by the amount of water dissolved.

8.
J Org Chem ; 80(15): 7572-80, 2015 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-26153917

RESUMO

Many imidazole (IMZ) derivatives of pharmaceutical interest, which are potentially catalytic in dephosphorylation reactions, are soluble solely in mixtures of water and organic solvent. In order to understand these poorly explored reactions and properly compare them, a thorough study related to solvent effects for the analogous spontaneous reaction and with common IMZ derivatives is necessary, which is lacking in the literature. Herein, we report a quantitative solvent effect analysis in DMSO/water mixtures for (i) the hydrolysis reaction of diethyl 2,4-dinitrophenylphosphate (DEDNPP) and (ii) the nucleophilic reaction of IMZ and 1-methylimidazole (MEI) with DEDNPP. The solvent effect was fitted satisfactorily with multiple regression analysis, correlating the obtained second-order rate constants with solvent parameters such as acidity, basicity, and polarity/polarizability from Catalán's scale. The contribution of these parameters can be taken into account to elucidate the reactivity in these media. Interestingly, IMZ is more reactive than MEI in DMSO, compared to water alone, which is attributed to the availability of hydrogen-bond formation. Nuclear magnetic resonance spectroscopy ((1)H, (13)C, and (31)P), mass spectrometry, thermodynamic analysis, and density functional theory calculations were carried out to corroborate the proposed nucleophilic mechanism.


Assuntos
2,4-Dinitrofenol/análogos & derivados , Dimetil Sulfóxido/química , Imidazóis/química , Organofosfatos/química , Solventes/química , Água/química , 2,4-Dinitrofenol/química , Catálise , Ésteres , Cinética , Espectroscopia de Ressonância Magnética , Fosfatos/química
9.
Int J Exp Pathol ; 95(5): 321-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24976301

RESUMO

Infection by Trypanosoma cruzi, the aetiological agent of Chagas disease, causes an intense inflammatory reaction in several tissues, including the myocardium. We have previously shown that transplantation of bone marrow cells (BMC) ameliorates the myocarditis in a mouse model of chronic Chagas disease. We investigated the participation of BMC in lesion repair in the heart and skeletal muscle, caused by T. cruzi infection in mice. Infection with a myotropic T. cruzi strain induced an increase in the percentage of stem cells and monocytes in the peripheral blood, as well as in gene expression of chemokines SDF-1, MCP1, 2, and 3 in the heart and skeletal muscle. To investigate the fate of BMC within the damaged tissue, chimeric mice were generated by syngeneic transplantation of green fluorescent protein (GFP(+) ) BMC into lethally irradiated mice and infected with Trypanosoma cruzi. Migration of GFP(+) BMC to the heart and skeletal muscle was observed during and after the acute phase of infection. GFP(+) cardiomyocytes and endothelial cells were present in heart sections of chimeric chagasic mice. GFP(+) myofibres were observed in the skeletal muscle of chimeric mice at different time points following infection. In conclusion, BMC migrate and contribute to the formation of new resident cells in the heart and skeletal muscle, which can be detected both during the acute and the chronic phase of infection. These findings reinforce the role of BMC in tissue regeneration.


Assuntos
Células da Medula Óssea/citologia , Movimento Celular , Doença de Chagas/parasitologia , Coração/parasitologia , Músculo Esquelético/metabolismo , Miocárdio/citologia , Trypanosoma cruzi , Animais , Cardiomiopatia Chagásica/metabolismo , Doença de Chagas/patologia , Quimiocinas/metabolismo , Doença Crônica , Modelos Animais de Doenças , Feminino , Camundongos Endogâmicos C57BL , Músculo Esquelético/patologia , Miocárdio/metabolismo , Trypanosoma cruzi/fisiologia
10.
FASEB J ; 27(12): 4691-702, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23964077

RESUMO

Chagas disease, caused by Trypanosoma cruzi infection, is a leading cause of heart failure in Latin American countries. In a previous study, we showed beneficial effects of granulocyte colony-stimulating factor (G-CSF) administration in the heart function of mice with chronic T. cruzi infection. Presently, we investigated the mechanisms by which this cytokine exerts its beneficial effects. Mice chronically infected with T. cruzi were treated with human recombinant G-CSF (3 courses of 200 µg/kg/d for 5 d). Inflammation and fibrosis were reduced in the hearts of G-CSF-treated mice, compared with the hearts of vehicle-treated mice, which correlated with decreased syndecan-4, intercellular adhesion molecule-1, and galectin-3 expressions. Marked reductions in interferon-γ and tumor necrosis factor-α and increased interleukin-10 and transforming growth factor-ß were found after G-CSF administration. Because the therapy did not induce a Th1 to Th2 immune response deviation, we investigated the role of regulatory T (Treg) cells. A significant increase in CD3(+)Foxp3(+) cells was observed in the hearts of G-CSF-treated mice. In addition, a reduction of parasitism was observed after G-CSF treatment. Our results indicate a role of Treg cells in the immunosuppression induced by G-CSF treatment and reinforces its potential therapeutic use for patients with Chagas disease.


Assuntos
Cardiomiopatia Chagásica/tratamento farmacológico , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Imunomodulação , Miocardite/tratamento farmacológico , Linfócitos T Reguladores/efeitos dos fármacos , Animais , Complexo CD3/genética , Complexo CD3/metabolismo , Cardiomiopatia Chagásica/imunologia , Cardiomiopatia Chagásica/metabolismo , Citocinas/genética , Citocinas/metabolismo , Fibrose/tratamento farmacológico , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Galectina 3/genética , Galectina 3/metabolismo , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Fator Estimulador de Colônias de Granulócitos/imunologia , Coração/parasitologia , Humanos , Injeções Intraperitoneais , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/imunologia , Miocárdio/metabolismo , Miocárdio/patologia , Carga Parasitária , Sindecana-4/genética , Sindecana-4/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Transcrição Gênica , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/patogenicidade
11.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 2): o105, 2014 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-24764837

RESUMO

In the title compound, C13H10O4·H2O, both the carboxylic acid [Car-Car-C-O = -121.1 (2)°, where ar = aromatic] and the ester [Car-Car-O-C = -104.4 (3)°] groups lie out of the mean plane of the conjugated aromatic system. In the crystal, the organic mol-ecule is hydrogen bonded to water mol-ecules through the ester and carb-oxy moieties, forming chains along the a-axis direction. The methyl H atoms of the acet-oxy group are disordered over two equally occupied sites.

12.
Analyst ; 138(2): 509-17, 2013 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-23166910

RESUMO

A bio-inspired complex, [(bpbpmp)Fe(III)(m-OAc)(2)Cu(II)](ClO(4)), was combined with a zwitterionic surfactant (ImS3-14) stabilizing pre-formed palladium nanoparticles and coated on a glassy carbon electrode (GCE). This bio-inspired surfactant film was capable of catalyzing redox reactions of dihydroxybenzenes, thus allowing the simultaneous electrochemical quantification of CC and HQ in cigarette residue samples by square-wave voltammetry (SWV). The best experimental conditions were obtained using phosphate buffer solution (0.1 mol L(-1), pH 7.0), with 1.3 nmol of the bio-inspired complex, 0.15 µmol of the surfactant and 1.08 nmol of Pd. The best voltammetric parameters were: frequency 100 Hz, pulse amplitude 40 mV and step potential 8 mV. The limits of detection calculated from simultaneous curves were found to be 2.2 × 10(-7) and 2.1 × 10(-7) mol L(-1) for HQ and CC respectively.


Assuntos
Técnicas Biossensoriais , Catecóis/análise , Poluentes Ambientais/análise , Hidroquinonas/análise , Fenol/química , Catecóis/química , Poluentes Ambientais/química , Compostos Férricos , Hidroquinonas/química , Chumbo/química , Nanopartículas Metálicas/química , Oxirredução , Paládio/química , Tensoativos/química , Alcatrões/análise , Alcatrões/química
13.
Front Cell Dev Biol ; 11: 1206049, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37576604

RESUMO

Background: Leishmaniasis results in a wide spectrum of clinical manifestations, ranging from skin lesions at the site of infection to disseminated lesions in internal organs, such as the spleen and liver. While the ability of Leishmania-infected host cells to migrate may be important to lesion distribution and parasite dissemination, the underlying mechanisms and the accompanying role of host cells remain poorly understood. Previously published work has shown that Leishmania infection inhibits macrophage migration in a 2-dimensional (2D) environment by altering actin dynamics and impairing the expression of proteins involved in plasma membrane-extracellular matrix interactions. Although it was shown that L. infantum induces the 2D migration of dendritic cells, in vivo cell migration primarily occurs in 3-dimensional (3D) environments. The present study aimed to investigate the migration of macrophages and dendritic cells infected by Leishmania using a 3-dimensional environment, as well as shed light on the mechanisms involved in this process. Methods: Following the infection of murine bone marrow-derived macrophages (BMDM), human macrophages and human dendritic cells by L. amazonensis, L. braziliensis, or L. infantum, cellular migration, the formation of adhesion complexes and actin polymerization were evaluated. Results: Our results indicate that Leishmania infection inhibited 3D migration in both BMDM and human macrophages. Reduced expression of proteins involved in adhesion complex formation and alterations in actin dynamics were also observed in Leishmania-infected macrophages. By contrast, increased human dendritic cell migration in a 3D environment was found to be associated with enhanced adhesion complex formation and increased actin dynamics. Conclusion: Taken together, our results show that Leishmania infection inhibits macrophage 3D migration, while enhancing dendritic 3D migration by altering actin dynamics and the expression of proteins involved in plasma membrane extracellular matrix interactions, suggesting a potential association between dendritic cells and disease visceralization.

14.
Neurobiol Dis ; 46(2): 302-13, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22198377

RESUMO

Approximately 30% of patients with mesial temporal lobe epilepsy do not respond to treatment with antiepileptic drugs. We have previously shown that transplantation of mononuclear bone marrow cells (BMC) has an anticonvulsant effect in acute epilepsy. Here, we used pilocarpine to induce epilepsy in rats and studied the effects of BMC injected intravenously either at the onset of seizures or after 10 months of recurrent seizures. BMC effectively decreased seizure frequency and duration. In addition, decreased levels of proinflammatory cytokines (TNF-α, IL-1ß and IL-6) and increased levels of anti-inflammatory cytokine (IL-10) were observed in the brain and serum of BMC-treated rats. Transplants performed at seizure-onset protected against pilocarpine-induced neuronal loss and gliosis and stimulated the proliferation of new neurons in epileptic rats. Our data demonstrate that BMC transplantation has potent therapeutic effects and could be a potential therapy for clinically intractable epilepsies.


Assuntos
Transplante de Medula Óssea , Citocinas/biossíntese , Epilepsia/metabolismo , Epilepsia/cirurgia , Leucócitos Mononucleares/transplante , Neurônios/metabolismo , Animais , Transplante de Medula Óssea/métodos , Transplante de Medula Óssea/patologia , Movimento Celular/fisiologia , Epilepsia/patologia , Incidência , Mediadores da Inflamação/metabolismo , Leucócitos Mononucleares/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/patologia , Ratos , Ratos Wistar
15.
Langmuir ; 28(1): 833-40, 2012 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-22126124

RESUMO

Palladium nanoparticles (NPs) with an average size of 3.4 nm were prepared in water using imidazolium-based surfactant 3-(1-dodecyl-3-imidazolio)propanesulfonate (ImS3-12) as a stabilizer. The Pd NPs are highly dispersible in water and chloroform and were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and dynamic light scattering. The results indicate that in water the NP surface is covered with a double layer of ImS3-12 molecules. The NPs were effective in the aqueous biphasic hydrogenation of cyclohexene, with easy recycling and no loss of catalytic activity after four successive runs.

16.
Sci Rep ; 12(1): 15774, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36131006

RESUMO

Heterogeneous chemical processes occupy a pivotal position in many fields of applied chemistry. Monitoring reaction kinetics in such heterogeneous systems together with challenges associated with ex-situ analytical methodologies can lead to inaccurate information about the nature of the catalyst surfaces as well as information about the steps involved. The present work explores the possibility of kinetic measurements of chemical reactions and adsorption processes of homogeneous and heterogeneous systems through the variation of RGB intensities of digital images using a smartphone combined with a program written in Python to accelerate and facilitate data acquisition. In order to validate the method proposed, the base promoted hydrolysis of 4-nitrophenyl acetate was initially investigated. The rate constants obtained through RGB analysis (0.01854 min-1) is almost identical to that using traditional UV-Vis spectroscopy (0.01848 min-1). The proposed method was then applied to monitor the kinetics of three heterogeneous processes: (1) reduction of 4-nitrophenolate in the presence of dispersed Pd/C; (2) decomposition of methyl orange with TiO2; and (3) adsorption of rhodamine on montmorillonite. In general, the method via digital images showed high reproducibility and analytical frequency, allowing the execution of simultaneous analyses, with an accuracy comparable to UV-Vis spectrophotometry. The method developed herein is a practical and valuable alternative for obtaining kinetic data of heterogeneous reactions and processes where a color change is involved, bypassing sampling collection and processing which decreases analytical frequency and may lead to data errors.


Assuntos
Bentonita , Smartphone , Cinética , Reprodutibilidade dos Testes , Rodaminas
17.
Front Pharmacol ; 13: 858190, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35479309

RESUMO

Agathisflavone is a flavonoid with anti-neuroinflammatory and myelinogenic properties, being also capable to induce neurogenesis. This study evaluated the therapeutic effects of agathisflavone-both as a pharmacological therapy administered in vivo and as an in vitro pre-treatment aiming to enhance rat mesenchymal stem cells (r)MSCs properties-in a rat model of acute spinal cord injury (SCI). Adult male Wistar rats (n = 6/group) underwent acute SCI with an F-2 Fogarty catheter and after 4 h were treated daily with agathisflavone (10 mg/kg ip, for 7 days), or administered with a single i.v. dose of 1 × 106 rMSCs either unstimulated cells (control) or pretreated with agathisflavone (1 µM, every 2 days, for 21 days in vitro). Control rats (n = 6/group) were treated with a single dose methylprednisolone (MP, 60 mg/kg ip). BBB scale was used to evaluate the motor functions of the animals; after 7 days of treatment, the SCI area was analyzed after H&E staining, and RT-qPCR was performed to analyze the expression of neurotrophins and arginase. Treatment with agathisflavone alone or with of 21-day agathisflavone-treated rMSCs was able to protect the injured spinal cord tissue, being associated with increased expression of NGF, GDNF and arginase, and reduced macrophage infiltrate. In addition, treatment of animals with agathisflavone alone was able to protect injured spinal cord tissue and to increase expression of neurotrophins, modulating the inflammatory response. These results support a pro-regenerative effect of agathisflavone that holds developmental potential for clinical applications in the future.

18.
Front Cardiovasc Med ; 9: 864837, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35757326

RESUMO

Aim: Previous studies showed that granulocyte-colony stimulating factor (G-CSF) improved heart function in a mice model of Chronic Chagas Cardiomyopathy (CCC). Herein, we report the interim results of the safety and efficacy of G-CSF therapy vs. placebo in adults with Chagas cardiomyopathy. Methods: Patients with CCC, New York Heart Association (NYHA) functional class II to IV and left ventricular ejection fraction (LVEF) 50% or below were included. A randomization list using blocks of 2 and 4 and an allocation rate of 1:1 was generated by R software which was stratified by functional class. Double blinding was done to both arms and assessors were masked to allocations. All patients received standard heart failure treatment for 2 months before 1:1 randomization to either the G-CSF (10 mcg/kg/day subcutaneously) or placebo group (1 mL of 0.9% saline subcutaneously). The primary endpoint was either maintenance or improvement of NYHA class from baseline to 6-12 months after treatment, and intention-to-treat analysis was used. Results: We screened 535 patients with CCC in Salvador, Brazil, of whom 37 were randomized. Overall, baseline characteristics were well-balanced between groups. Most patients had NYHA class II heart failure (86.4%); low mean LVEF was 32 ± 7% in the G-CSF group and 33 ± 10% in the placebo group. Frequency of primary endpoint was 78% (95% CI 0.60-0.97) vs. 66% (95% CI 0.40-0.86), p = 0.47, at 6 months and 68% (95% CI 0.43-0.87) vs. 72% (95% CI 0.46-0.90), p = 0.80, at 12 months in placebo and G-CSF groups, respectively. G-CSF treatment was safe, without any related serious adverse events. There was no difference in mortality between both arms, with five deaths (18.5%) in treatment vs. four (12.5%) in the placebo arm. Exploratory analysis demonstrated that the maximum rate of oxygen consumption during exercise (VO2 max) showed an improving trend in the G-CSF group. Conclusion: G-CSF therapy was safe and well-tolerated in 12 months of follow-up. Although prevention of symptom progression could not be demonstrated in the present study, our results support further investigation of G-CSF therapy in Chagas cardiomyopathy patients. Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [NCT02154269].

19.
Org Biomol Chem ; 9(17): 6163-70, 2011 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-21785773

RESUMO

Hydrolysis of alkyl 1,8-naphthalic acid monoesters 1a-d is subject to highly efficient intramolecular nucleophilic catalysis by the neighboring COOH group. The reactivity for the COOH reaction depends on the leaving group pK(a), with values of ß(LG) of -0.50, consistent with a mechanism involving rate determining breakdown of tetrahedral addition intermediates. The release of the steric strain of the peri-substitiuents in the highly reactive alkyl 1,8-naphthalic acid monoesters is fundamental to understand the observed special reactivity in this intramolecular reaction. DFT calculations show how the proton transfers involved in the cleavage of the neutral ester can be catalyzed by solvent water, thus facilitating the departure of poor alkoxide leaving groups.


Assuntos
Naftalenos/química , Catálise , Ésteres/química , Hidrólise , Modelos Moleculares
20.
Front Fungal Biol ; 2: 805502, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-37744114

RESUMO

Paracoccidioides sp.-Herpes simplex virus (HSV) co-infection was not reported until now and malabsorption syndrome is a rare complication of the acute/subacute form (AF) of paracoccidioidomycosis (PCM), characterized by life-threatening abnormalities, such as fat and protein loss, lymphopenia, ascites, and intense immunosuppression. A 21-year-old woman presented the PCM AF with intense involvement of the abdominal and intestinal lymphoid organs, which leads to the malabsorption syndrome and severe immunosuppression. This patient developed a fatal-disseminated HSV infection associated with the paracoccidioidal disease. This case demonstrates that, in addition to the antigen-specific immunosuppression, some PCM patients can present a generalized cell-mediated immune depression and endogenous infection of latent microorganisms. On the best of our knowledge, this is the first report of an association between PCM and HSV infection.

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