31 results on '"Silva AMG"'
Search Results
2. UV Dermoscopy for the Diagnosis of Pityrosporum Folliculitis.
- Author
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Silva AMG, Michalany AO, and de Sá Menezes Carvalho G
- Published
- 2024
- Full Text
- View/download PDF
3. Hybrid Zn-β-Aminoporphyrin-Carbon Nanotubes: Pyrrolidine and Direct Covalent Linkage Recognition, and Multiple-Photo Response.
- Author
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Rebelo SLH, Laia CAT, Szefczyk M, Guedes A, Silva AMG, and Freire C
- Abstract
To unveil and shape the molecular connectivity in (metallo)porphyrin-carbon nanotube hybrids are of main relevance for the multiple medicinal, photoelectronic, catalytic, and photocatalytic applications of these materials. Multi-walled carbon nanotubes (MWCNTs) were modified through 1,3-dipolar cycloaddition reactions with azomethine ylides generated in situ and carrying pentafluorophenyl groups, followed by immobilization of the β-amino-tetraphenylporphyrinate Zn(II). The functionalities were confirmed via XPS and FTIR, whereas Raman spectroscopy showed disruptions on the graphitic carbon nanotube surface upon both steps. The functionalization extension, measured via TGA mass loss and corroborated via XPS, was 0.2 mmol·g
-1 . Photophysical studies attest to the presence of the different porphyrin-carbon nanotube connectivity in the nanohybrid. Significantly different emission spectra and fluorescence anisotropy of 0.15-0.3 were observed upon variation of excitation wavelength. Vis-NIR absorption and flash photolysis experiments showed energy/charge transfer in the photoactivated nanohybrid. Moreover, evidence was found for direct reaction of amino groups with a carbon nanotube surface in the presence of molecular dipoles such as the zwitterionic sarcosine amino acid.- Published
- 2023
- Full Text
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4. Microwave-Assisted Synthesis and Spectral Properties of Pyrrolidine-Fused Chlorin Derivatives.
- Author
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Almeida J, Tomé AC, Rangel M, and Silva AMG
- Abstract
In this work we pursued research involving the microwave-assisted N -alkylation of a NH pyrrolidine-fused chlorin with methyl 4-(bromomethyl) benzoate and subsequent ester hydrolysis as a straightforward strategy to obtain carboxylic acid functionality in the pyrrolidine-fused chlorin, as a single reaction product. We studied the reaction's scope by extending the N -alkylation of the free-base chlorin and its corresponding Zn(II) complex to other alkyl halides, including 1,4-diiodobutane, N -(2-bromoethyl)phthalimide, and 2-bromoethanaminium bromide. In addition, two new chlorin-dansyl dyads were synthesized by reacting dansyl chloride with the 2-aminoethyl pyrrolidine-fused chlorin (dyad 6 ) and NH pyrrolidine-fused chlorin (dyad 7 ). According to spectral studies, the linker length between the two fluorophores influences the response of the dyads to the solvent polarity. Because of the simplicity of these approaches, we believe it will enable access to a vast library of custom-tailored N -functionalized chlorins while preserving their important absorption and emission spectra as photosensitizers in photodynamic therapy (PDT) of cancer and photodynamic inactivation (PDI) of microorganisms.
- Published
- 2023
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5. Long non-coding RNA and circular RNA: new perspectives for molecular pathophysiology of atrial fibrillation.
- Author
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da Silva AMG, Cruz MS, de Souza KSC, and Silbiger VN
- Subjects
- Humans, RNA, Circular genetics, Gene Expression Profiling methods, RNA, Messenger genetics, Gene Regulatory Networks, Atrial Fibrillation genetics, RNA, Long Noncoding genetics, RNA, Long Noncoding metabolism, MicroRNAs genetics
- Abstract
Many studies have demonstrated the association of atrial fibrillation (AF) with endogenous genetic regulatory mechanisms. These interactions could advance the understanding of the AF pathophysiological process, supporting the search for early biomarkers to improve diagnosis and disease monitoring. Among the endogenous genetic regulatory mechanisms, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) have gained special attention, and studies have demonstrated their involvement in AF development and other AF-related diseases such as coronary artery disease and cardiomyopathy. This review describes the main experimental results reported by studies that analyzed the expression of lncRNAs and circRNAs in AF associated with miRNA or mRNA. The search was conducted in PubMed public database using the terms "lncRNA and atrial fibrillation" or "long ncRNA and atrial fibrillation" or "long non-coding RNA and atrial fibrillation" or "circular RNA and atrial fibrillation" or "circRNA and atrial fibrillation". There was no overlapping of lncRNA or circRNA among the studies, attributed to the different sample types, methods, species, and patient classification evaluated in these studies. Although the regulatory mechanisms in which these molecules are involved are not yet well understood, the studies analyzed show their importance in the pathophysiological process of AF, supporting the idea that lncRNAs and circRNAs are involved in miRNA or mRNA regulation in the molecular mechanism of this disease., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)
- Published
- 2023
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6. Selective Determination of Glutathione Using a Highly Emissive Fluorescent Probe Based on a Pyrrolidine-Fused Chlorin.
- Author
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Moscoso FG, Queirós C, González P, Lopes-Costa T, Silva AMG, and Pedrosa JM
- Subjects
- Fluorescent Dyes chemistry, Glutathione, Ions, Spectrometry, Fluorescence, Porphyrins chemistry, Mercury
- Abstract
We report the use of a carboxylated pyrrolidine-fused chlorin (TCPC) as a fluorescent probe for the determination of glutathione (GSH) in 7.4 pH phosphate buffer. TCPC is a very stable, highly emissive molecule that has been easily obtained from meso-tetrakis(4-methoxycarbonylphenyl) porphyrin (TCPP) through a 1,3-dipolar cycloaddition approach. First, we describe the coordination of TCPC with Hg(II) ions and the corresponding spectral changes, mainly characterized by a strong quenching of the chlorin emission band. Then, the TCPC-Hg
2+ complex exhibits a significant fluorescence turn-on in the presence of low concentrations of the target analyte GSH. The efficacy of the sensing molecule was tested by using different TCPC:Hg2+ concentration ratios (1:2, 1:5 and 1:10) that gave rise to sigmoidal response curves in all cases with modulating detection limits, being the lowest 40 nM. The experiments were carried out under physiological conditions and the selectivity of the system was demonstrated against a number of potential interferents, including cysteine. Furthermore, the TCPC macrocycle did not showed a significant fluorescent quenching in the presence of other metal ions.- Published
- 2023
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7. Biogenic Amine Sensing Based on Rosamine a N -Methylpyridinium Derivative Supported on Silica Materials from Rice Husk.
- Author
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Queirós C, Ribeiro SO, Silva AMG, and Leite A
- Subjects
- Cadaverine, Putrescine, Biogenic Amines, Silicon Dioxide, Oryza
- Abstract
In this work new rosamine-silica composites were prepared and their sensing ability towards different amines was assessed. Rice husk wastes were used as a biogenic silica source. Silica was extracted by thermal treatment, before rice husk ash and after acid leaching with citric acid-treated rice husk ash. Mesoporous material (SBA-15) was also prepared using the extracted silica. The prepared materials were characterized by several techniques such as FTIR, XRD, SEM and N
2 adsorption. The materials were then used as adsorbents of the chromophore N- methylpyridinium rosamine (Ros4PyMe). The obtained loaded composites were tested in solution for amines sensing ( n- butylamine, aniline, putrescine and cadaverine). The detection studies were analyzed by fluorescence and revealed 40% and 48% quenching in fluorescence intensity for the composite Ros4PyMe@SBA in the presence of the biogenic amines cadaverine and putrescine, respectively. The composite was also sensitive in the powder form, changing the color from violet to pale pink in the presence of putrescine vapors with a fast response (around 2 min), the process being reversible by exposure to air.- Published
- 2022
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8. Skin fibrosis associated with keloid, scleroderma and Jorge Lobo's disease (lacaziosis): An immuno-histochemical study.
- Author
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Tafuri WL, Tomokane TY, Silva AMG, Kanashiro-Galo L, Mosser DM, Quaresma JAS, Pagliari C, and Sotto MN
- Subjects
- Humans, Endothelial Cells metabolism, Endothelial Cells pathology, Fibroblasts metabolism, Fibrosis, Forkhead Transcription Factors metabolism, Ki-67 Antigen metabolism, Transforming Growth Factor beta metabolism, Vimentin metabolism, Keloid metabolism, Keloid pathology, Lobomycosis pathology, Scleroderma, Localized metabolism, Scleroderma, Localized pathology, Skin metabolism, Skin pathology
- Abstract
Fibrosis is a common pathophysiological response of many tissues and organs subjected to chronic injury. Despite the diverse aetiology of keloid, lacaziosis and localized scleroderma, the process of fibrosis is present in the pathogenesis of all of these three entities beyond other individual clinical and histological distinct characteristics. Fibrosis was studied in 20 samples each of these three chronic cutaneous inflammatory diseases. An immunohistochemical study was carried out to explore the presence of α-smooth muscle actin (α-SMA) and vimentin cytoskeleton antigens, CD31, CD34, Ki67, p16; CD105, CD163, CD206 and FOXP3 antigens; and the central fibrotic cytokine TGF-β. Higher expression of vimentin in comparison to α-SMA in all three lesion types was found. CD31- and CD34-positive blood vessel endothelial cells were observed throughout the reticular dermis. Ki67 expression was low and almost absent in scleroderma. p16-positive levels were higher than ki67 and observed in reticular dermis of keloidal collagen in keloids, in collagen bundles in scleroderma and in the external layers of the granulomas in lacaziosis. The presence of α-actin positive cells and rarely CD34 positive cells, observed primarily in keloids, may be related to higher p16 antigen expression, a measure of cell senescence. Low FOXP3 expression was observed in all lesion types. CD105-positive cells were mainly found in perivascular tissue in close contact with the adventitia in keloids and scleroderma, while, in lacaziosis, these cells were chiefly observed in conjunction with collagen deposition in the external granuloma layer. We did not find high involvement of CD163 or CD206-positive cells in the fibrotic process. TGF-β was notable only in keloid and lacaziosis lesions. In conclusion, we have suggested vimentin to be the main myofibroblast general marker of the fibrotic process in all three studied diseases, while endothelial-to-mesenchymal transition (EndoMT) and mesenchymal stem cells (MSCs) and M2 macrophages may not play an important role., (© 2022 Company of the International Journal of Experimental Pathology (CIJEP).)
- Published
- 2022
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9. Synthesis of Novel Diketopyrrolopyrrole-Rhodamine Conjugates and Their Ability for Sensing Cu 2+ and Li .
- Author
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Queirós C, Almodôvar VAS, Martins F, Leite A, Tomé AC, and Silva AMG
- Subjects
- Humans, Rhodamines chemistry, Cations, Spectrometry, Fluorescence, Fluorescent Dyes chemistry, Copper analysis
- Abstract
The search for accurate and sensitive methods to detect chemical substances, namely cations and anions, is urgent and widely sought due to the enormous impact that some of these chemical species have on human health and on the environment. Here, we present a new platform for the efficient sensing of Cu
2+ and Li+ cations. For this purpose, two novel photoactive diketopyrrolopyrrole-rhodamine conjugates were synthesized through the condensation of a diketopyrrolopyrrole dicarbaldehyde with rhodamine B hydrazide. The resulting chemosensors 1 and 2 , bearing one or two rhodamine hydrazide moieties, respectively, were characterized by1 H and13 C NMR and high-resolution mass spectrometry, and their photophysical and ion-responsive behaviours were investigated via absorption and fluorescence measurements. Chemosensors 1 and 2 displayed a rapid colorimetric response upon the addition of Cu2+ , with a remarkable increase in the absorbance and fluorescence intensities. The addition of other metal ions caused no significant effects. Moreover, the resulting chemosensor-Cu2+ complexes revealed to be good probes for the sensing of Li+ with reversibility and low detection limits. The recognition ability of the new chemosensors was investigated by absorption and fluorescence titrations and competitive studies.- Published
- 2022
- Full Text
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10. Modelling Hyperglycaemia in an Epithelial Membrane Model: Biophysical Characterisation.
- Author
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Reis A, Teixeira JPF, Silva AMG, Ferreira M, Gameiro P, and de Freitas V
- Subjects
- Humans, Cholesterol analysis, Glucose, Phenols, Sphingolipids, Tandem Mass Spectrometry, Biophysical Phenomena, Hyperglycemia, Phosphatidylethanolamines chemistry
- Abstract
Biomimetic models are valuable platforms to improve our knowledge on the molecular mechanisms governing membrane-driven processes in (patho)physiological conditions, including membrane permeability, transport, and fusion. However, current membrane models are over simplistic and do not include the membrane's lipid remodelling in response to extracellular stimuli. Our study describes the synthesis of glycated dimyristoyl-phosphatidylethanolamine (DMPE-glyc), which was structurally characterised by mass spectrometry (ESI-MS) and quantified by NMR spectroscopy to be further incorporated in a complex phospholipid (PL) membrane model enriched in cholesterol (Chol) and (glyco)sphingolipids (GSL) designed to mimic epithelial membranes (PL/Chol/GSL) under hyperglycaemia conditions. Characterisation of synthesised DMPE-glyc adducts by tandem mass spectrometry (ESI-MS/MS) show that synthetic DMPE-glyc adducts correspond to Amadori products and quantification by
1 H NMR spectroscopy show that the yield of glycation reaction was 8%. The biophysical characterisation of the epithelial membrane model shows that excess glucose alters the thermotropic behaviour and fluidity of epithelial membrane models likely to impact permeability of solutes. The epithelial membrane models developed to mimic normo- and hyperglycaemic scenarios are the basis to investigate (poly)phenol-lipid and drug-membrane interactions crucial in nutrition, pharmaceutics, structural biochemistry, and medicinal chemistry.- Published
- 2022
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11. Ohmic heating-assisted synthesis and characterization of Zn(II), Cu(II) and Pd(II) complexes of heterocyclic-fused chlorins.
- Author
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Moreira MIF, Almeida J, Leite A, Lobo Ferreira AIMC, Santos LMNBF, Silva AMG, and Rangel M
- Abstract
Chlorins are highly interesting compounds due to their spectroscopic properties in both UV-Vis and NIR regions. Upon coordination to a metal ion, the corresponding metallochlorins exhibit more valuable physicochemical properties that enable a broader range of applications, such as in photodynamic therapy (PDT), water splitting catalysis, optical sensor devices and dye-sensitized solar cells. Synthetic chemistry has been in a continuous quest to fulfil most green chemistry requirements through the development of efficient reactions. Being a heating process that does not depend on heat transfer to the reaction medium, ohmic heating accomplishes the mentioned requirements and allows a fast and uniform heating regime thanks to the ionic conductivity of the reaction medium. Herein, we report the metallation of pyrrolidine- and isoxazolidine-fused chlorins with Zn(II), Cu(II) and Pd(II) salts by ohmic heating, using non-toxic aqueous solutions, and their corresponding physico-chemical characterization. All pyrrolidine-fused chlorins showed higher yields, when compared with isoxazolidine ones. From the thermogravimetric analysis performed it is possible to infer that the metal enhances the steadiness of the macrocycle, making it easier to cause the thermal decomposition of the pyrrolidine- and isoxazolidine-fused chlorins. The Zn(II) complexes showed high absorption in the NIR spectral region, a low fluorescence quantum yield and a short excited singlet state, which indicate the high efficiency of intersystem crossing to the triplet state, making them very promising candidates as photosensitizers for PDT.
- Published
- 2022
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12. Functionalization of Rhodamine Platforms with 3-Hydroxy-4-pyridinone Chelating Units and Its Fluorescence Behavior towards Fe(III).
- Author
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Queirós C, Vinhas S, Oliveira J, Leite A, Silva AMG, and Rangel M
- Abstract
Functionalization of xanthene fluorophores with specific receptor units is an important topic of research aiming for the development of new analytical tools for biological sciences, clinical diagnosis, food and environmental monitoring. Herein, we report a new dihydrorosamine containing two active amino groups, which was functionalized with 3-benzyloxy-1-(3'-carboxypropyl)-2-methyl-4-pyridinone through an amide coupling strategy. Benzylated mono- and di-functionalized dihydrorosamine derivatives (H in position 9 of the xanthene) were obtained, but with modest reaction yields, requiring long and laborious purification procedures. Looking for a more efficient approach, rhodamine 110 was selected to react with the carboxypropyl pyridinone, enabling the isolation of the corresponding mono- and di-functionalized derivatives in amounts that depend on the excess of pyridinone added to the reaction. The structure of all compounds was established by
1 H and13 C NMR, MS (ESI) and their absorption and emission properties were evaluated in dichloromethane. The fluorescence behavior of the debenzylated mono-rhodamine 110 derivative in the presence of Fe(III) was studied, making it an interesting fluorogenic dye for future optical sensing applications.- Published
- 2022
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13. Synthesis of Catechol Derived Rosamine Dyes and Their Reactivity toward Biogenic Amines.
- Author
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Monteiro-Silva F, Queirós C, Leite A, Rodríguez MT, Rojo MJ, Torroba T, Martins RC, Silva AMG, and Rangel M
- Subjects
- Coloring Agents chemistry, Fluorescence, Heterocyclic Compounds, 3-Ring chemistry, Rhodamines chemistry, Spectrum Analysis, Biogenic Amines chemistry, Catechols chemistry, Coloring Agents chemical synthesis, Heterocyclic Compounds, 3-Ring chemical synthesis, Rhodamines chemical synthesis
- Abstract
Functional organic dyes play a key role in many fields, namely in biotechnology and medical diagnosis. Herein, we report two novel 2,3- and 3,4-dihydroxyphenyl substituted rosamines ( 3 and 4 , respectively) that were successfully synthesized through a microwave-assisted protocol. The best reaction yields were obtained for rosamine 4 , which also showed the most interesting photophysical properties, specially toward biogenic amines (BAs). Several amines including n - and t -butylamine, cadaverine, and putrescine cause spectral changes of 4 , in UV-Vis and fluorescence spectra, which are indicative of their potential application as an effective tool to detect amines in acetonitrile solutions. In the gas phase, the probe response is more expressive for spermine and putrescine. Additionally, we found that methanolic solutions of rosamine 4 and n -butylamine undergo a pink to yellow color change over time, which has been attributed to the formation of a new compound. The latter was isolated and identified as 5 (9-aminopyronin), whose solutions exhibit a remarkable increase in fluorescence intensity together with a shift toward more energetic wavelengths. Other 9-aminopyronins 6a , 6b , 7a , and 7b were obtained from methanolic solutions of 4 with putrescine and cadaverine, demonstrating the potential of this new xanthene entity to react with primary amines.
- Published
- 2021
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14. Synthesis, characterization, and cellular investigations of porphyrin- and chlorin-indomethacin conjugates for photodynamic therapy of cancer.
- Author
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Almeida J, Zhang G, Wang M, Queirós C, Cerqueira AFR, Tomé AC, Barone G, Vicente MGH, Hey-Hawkins E, Silva AMG, and Rangel M
- Abstract
Indomethacin is a potent non-steroidal anti-inflammatory drug (NSAID) with a strong selective inhibitor activity towards cyclooxygenase-2 (COX-2), an enzyme that is highly overexpressed in various tumour cells, being involved in tumourigenesis. Concomitantly, porphyrins have gained much attention as promising photosensitizers (PSs) for the non-invasive photodynamic therapy (PDT) of cancer. Herein, we report the design, and determine the singlet oxygen generation capacity and in vitro cellular toxicity of porphyrin- and chlorin-indomethacin conjugates (P2-Ind and C2-Ind). Both the conjugates were obtained in high yields and were characterized by 1H, 19F and 13C NMR as well as by high resolution mass spectrometry. The singlet oxygen generation properties were assessed by the 1,3-diphenylisobenzofuran singlet oxygen trap method, which showed that C2 and C2-Ind are the best singlet oxygen photosensitizers. In addition, it was found that the presence of indomethacin did not influence the singlet oxygen generation of porphyrin or chlorin. Cytotoxicity studies of the conjugate in human HEp2 cells revealed that the porphyrin- and chlorin-indomethacin conjugates have similar dark cytotoxicities, while chlorin C2 was shown to be the most phototoxic. Despite having lower cellular uptake than C2-Ind after 24 hours, chlorin C2 had a broad localization in HEp2 cells while the chlorin-indomethacin conjugate C2-Ind could be detected in the form of small aggregates. DFT calculations were performed to shed light on the reaction energy involved in the formation of the indomethacin conjugates and to compare the relative stability of selected isomers in solution. Moreover, the calculated energy of their first excited triplet state structures confirmed their use as suitable photosensitizers to generate singlet oxygen for PDT.
- Published
- 2021
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15. Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers.
- Author
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Queirós C, Sun C, Silva AMG, de Castro B, Cabanillas-Gonzalez J, and Cunha-Silva L
- Abstract
The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm
3+ /Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.- Published
- 2021
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16. A sensitive and reliable quantitative immunohistochemistry technique to evaluate the percentage of Trypanosoma cruzi-infected tissue area.
- Author
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Ferreira-Filho JCR, Braz LMA, Andrino MLA, Yamamoto L, Kanashiro EHY, da Silva AMG, Kanunfre KA, and Okay TS
- Subjects
- Animals, Biopsy instrumentation, Mice, Parasite Load instrumentation, Reproducibility of Results, Sensitivity and Specificity, Chagas Cardiomyopathy pathology, Heart parasitology, Immunohistochemistry methods, Myocardium pathology, Parasite Load methods, Trypanosoma cruzi isolation & purification
- Abstract
Quantification of parasites in the context of Chagas disease is required to monitor the treatment with benznidazole, disease-associated cardiomyopathies and graft rejection after heart transplantation. As parasitological exams lack sensitivity, Real Time Polymerase Chain Reaction (rt-PCR) has emerged to evaluate the parasite load in blood samples and cardiac biopsies. However, despite its higher sensitivity, rt-PCR does not provide information on the location and distribution of amastigote nests within infected tissues, the characterization of inflammatory infiltrates or changes to tissue architecture. On the contrary, a sensitive immunohistochemistry technique (IHC) could fill these gaps. In the present study, a quantitative IHC exam was standardized and validated by testing adipose and cardiac tissues of experimentally infected mice containing variable parasite load levels of T. cruzi assessed by a sensitive Sybr Green rt-PCR with kDNA primers. Tissues were divided into four groups according to the parasite load: group A- 100 parasites/50 ng of DNA; group B -10 parasites; group C - around 1 parasite and group D - less than 1 parasite/50 ng/DNA. IHC was able to detect T. cruzi in the four groups, even in group D tissues containing fractions of a single parasite/50 ng of DNA sample according to rt-PCR. In conclusion, a highly sensitivity and reliable quantitative immunohistochemistry technique was developed and is proposed to estimate the percentage of T. cruzi-infected tissue area in chagasic patients presenting with cardiomyopathies, as a complementary test to rt-PCR., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2021
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17. From Discrete Complexes to Metal-Organic Layered Materials: Remarkable Hydrogen Bonding Frameworks.
- Author
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Queirós C, Silva AMG, de Castro B, and Cunha-Silva L
- Subjects
- Hydrogen Bonding, Models, Molecular, Phthalic Acids chemical synthesis, Phthalic Acids chemistry, Spectroscopy, Fourier Transform Infrared, Temperature, Thermogravimetry, Vibration, Metals chemistry, Organic Chemicals chemistry
- Abstract
A series of metal-organic coordination complexes based on alkaline-earth metal centers [Mg(II), Ca(II), and Ba(II)] and the ligand 5-aminoisophthalate (aip
2- ) revealed notable structural diversity, both in the materials' dimensionality and in their hydrogen bonding networks: [Mg(H2 O)6 ]∙[Mg2 (Haip)(H2 O)10 ]∙(Haip)∙3(aip)∙10(H2 O) ( 1 ) and [Mg(aip)(phen)(H2 O)2 ]∙(H2 O) ( 2 ) were isolated as discrete complexes (0D); [Ca(aip)(H2 O)2 ]∙(H2 O) ( 3 ), [Ca(aip)(phen)(H2 O)2 ]∙(phen)∙(H2 O) ( 4 ), and [Ba2 (aip)2 (phen)2 (H2 O)7 ]∙2(phen)∙2(H2 O) ( 5 ) revealed metal-organic chain (1D) structures, while the [Ba(aip)(H2 O)] ( 6 ) showed a metal-organic layered (2D) arrangement. Furthermore, most of these metal-organic coordination materials revealed interesting thermal stability properties, being stable at temperatures up to 450 °C.- Published
- 2020
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18. miRNAs emerge as circulating biomarkers of post-myocardial infarction heart failure.
- Author
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Cruz MS, da Silva AMG, de Souza KSC, Luchessi AD, and Silbiger VN
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- Biomarkers blood, Heart Failure etiology, Humans, Myocardial Infarction blood, Prognosis, Heart Failure blood, MicroRNAs blood, Myocardial Infarction complications
- Abstract
Heart failure (HF) is a clinical syndrome that involves structural changes in the heart, leading to a decrease in cardiac output, mainly caused by myocardial infarction (MI), which is the most common form of cardiovascular disease worldwide. Clinical evaluation remains the most accurate diagnostic method for ischemic HF, since the known biomarkers have high cost, are difficult to use for early diagnosis, and have low specificity. This often leads to late diagnosis since only ~ 25% symptoms of HF appear after MI. Studies suggest that small non-coding RNAs (miRNAs) play an important role in the regulation of this pathophysiological process and are, therefore, important targets in the discovery of non-invasive biomarkers for HF. Thus, the aim of this review was to identify circulating miRNAs (plasma, serum, and whole blood) described for post-MI HF patients. This review covered 19 experimental studies on humans, which investigated the relationship between circulating miRNAs and the development, monitoring, or prognosis of ischemic HF. This analysis was aimed at proposing potential targets for HF and the future application of miRNAs as HF biomarkers.
- Published
- 2020
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19. Subppm Amine Detection via Absorption and Luminescence Turn-On Caused by Ligand Exchange in Metal Organic Frameworks.
- Author
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Sousaraei A, Queirós C, Moscoso FG, Lopes-Costa T, Pedrosa JM, Silva AMG, Cunha-Silva L, and Cabanillas-Gonzalez J
- Abstract
Luminescent metal-organic frameworks (LMOFs) are promising materials for lighting and sensing applications. Herein, exposure of the highly luminescent Zn
2 (bpdc)2 (bpee) MOF (H2 bpdc = 4,4'-biphenyldicarboxylic acid and bpee = 1,2-bipyridylethene) to subppm amine contents turns on a new absorption band unambiguously ascribed to free bpee molecules concomitant with the gradual appearance of a new photoluminescence band at shorter wavelengths. These findings combined with Fourier-transform infrared spectra, powder X-ray diffraction and thermogravimetric analysis of exposed LMOF powders confirm that bpee ligands are exchanged by amines and released inside the LMOF, triggering absorption and luminescence features which can be exploited for highly sensitive amine recognition. This principle was demonstrated in mixed matrix membranes (MMMs) prepared by a simple solvent-free method consisting of mixing Zn2 (bpdc)2 (bpee) with dimethylvinyl-terminated dimethylsiloxane and dimethylhydrogen siloxane. This method enabled the production of free-standing, permeable, and highly transparent MMMs which showed enormous potential and sensitivity to the detection of amines in gas phase and aqueous medium.- Published
- 2019
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20. Synthesis of Pyridyl and N-Methylpyridinium Analogues of Rosamines: Relevance of Solvent and Charge on Their Photophysical Properties.
- Author
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Leite A, Cunha-Silva L, Silva D, Lobo Ferreira AIMC, Santos LMNBF, Cardoso ICS, Silva VLM, Rangel M, and Silva AMG
- Abstract
A series of pyridyl analogues of rosamines was prepared by employing two methodologies: (i) the conventional-heating condensation of a pyridinecarboxaldehyde with 3-(diethylamino)phenol in propionic acid, and (ii) the novel ohmic-heating assisted condensation under "on water" conditions, followed by oxidation. The 4-pyridyl substituted rosamine was further converted into the N-methylpyridinium derivative through N-alkylation using methyl iodide. The influence of the position and cationization of the nitrogen atom of the pyridyl ring in the physicochemical properties of fluorophores was investigated by
1 H,13 C,15 N NMR spectral analysis, UV/Vis and fluorescence spectroscopy, single-crystal X-ray diffraction (4-pyridyl and N-methylpyridinium derivatives) and thermal-behavior analysis. Curiously, for ethanolic solutions of 4-pyridyl and N-methylpyridinium derivatives an extinction of color and fluorescence over time was observed. This phenomenon was further studied and the data revealed that it is the result of nucleophilic addition of ethoxide ion to the central 9-position of the xanthene. The kinetics of the process is slower for the 4-pyridyl rosamine, which emphasizes the importance of the charge in the N-methylpyridinium analogue in the reactivity of the molecule towards a nucleophile agent. This phenomenon is reversible, meaning that the compounds can be rapidly recovered by decreasing the pH, opening new avenues in the sensing applications of this class of rosamines., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2019
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21. Cytokine Profile in Early Infection by Leptospira interrogans in A/J Mice.
- Author
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Bavia L, de Castro ÍA, Amano MT, da Silva AMG, Vasconcellos SA, and Isaac L
- Subjects
- Animals, Biomarkers, Biopsy, Cytokines metabolism, Disease Models, Animal, Host-Pathogen Interactions, Leptospirosis metabolism, Leptospirosis pathology, Leukocyte Count, Liver metabolism, Liver microbiology, Liver pathology, Mice, Organ Specificity, Time Factors, Cytokines blood, Leptospira interrogans, Leptospirosis blood, Leptospirosis microbiology
- Abstract
Leptospirosis is considered a neglected disease with an estimated more than one million cases every year. Since rodents are at the same time the main reservoir and generally asymptomatic to Leptospira infection, understanding why some animal species are resistant and others are susceptible to this infection would shed some light in how to control this important zoonosis. The innate immune response against Leptospira is mainly dependent on phagocytosis and activation of the Complement System. In this context, cytokines may drive the early control of infection and the adaptive response. Since the Complement System is important to eliminate leptospires in vivo , we investigated if Complement C5 in A/J mice would modulate the cytokine production during infection by Leptospira interrogans serovar Kennewicki type Pomona Fromm (LPF). Thus, our aim was to investigate the systemic levels of pro- and anti-inflammatory cytokines during Leptospira infection in the blood, liver, lung, and kidney on the third and sixth days of infection in A/J C5
+/+ and A/J C5-/- mice. Blood levels of TNF- α , IL-6, IFN- γ , and MCP-1 reached a peak on the third day. Although both mouse strains developed splenomegaly, similar histopathological alterations in the liver and the lung, levels of pro- and anti-inflammatory cytokines were different. A/J C5+/+ mice had higher levels of liver IL-10, IL-1 β , IL-12p40, and IL-12p70 and kidney IL-1 β , IL-12p40, and IL-12p70 on the sixth day of infection when compared to A/J C5-/- mice. Our results showed that in A/J genetic background, the Complement component C5 modulates a cytokine profile in the liver and kidney of infected mice, which may play a role in the control of disease progression., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2019 Lorena Bavia et al.)- Published
- 2019
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22. Antibacterial activity of naphthyl derived bis-(3-hydroxy-4-pyridinonate) copper(II) complexes against multidrug-resistant bacteria.
- Author
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Leite A, Bessa LJ, Silva AMG, Gameiro P, de Castro B, and Rangel M
- Subjects
- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Anti-Bacterial Agents pharmacology, Coordination Complexes chemical synthesis, Coordination Complexes chemistry, Coordination Complexes pharmacology, Drug Resistance, Multiple, Bacterial drug effects, Enterococcus faecalis growth & development, Methicillin-Resistant Staphylococcus aureus growth & development, Vancomycin Resistance drug effects
- Abstract
In this work, we report the synthesis and characterization of three novel copper(II) complexes of naphthyl derived 3-hydroxy-4-pyridinone chelators. Their antibacterial activity against several Gram-positive and Gram-negative reference strains and multidrug-resistant clinical isolates was assessed through determination of the minimum inhibitory concentration (MIC). The complex Cu(naph1pp)
2 shows the highest antibacterial activity, including against multidrug-resistant isolates, nonetheless, being more active against Gram-positive than Gram-negative bacteria. Cu(naph1pp)2 was further explored in combinatorial tests with ciprofloxacin against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). The combination of Cu(naph1pp)2 and ciprofloxacin is considered additive, i.e., the effect of the two compounds combined is stronger than that of the individual compounds in the equivalent concentration., (Copyright © 2019 Elsevier Inc. All rights reserved.)- Published
- 2019
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23. TREML4 mRNA Expression and Polymorphisms in Blood Leukocytes are Associated with Atherosclerotic Lesion Extension in Coronary Artery Disease.
- Author
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Duarte VHR, Miranda CTOF, Cruz MS, de Araújo JNG, Duarte MKRN, Santos AMQSD, Santos ICCD, Santos JCD, da Silva AMG, de Oliveira JM, Paiva MSMO, de Oliveira Galvão MF, Rezende AA, Hirata MH, Hirata RDC, Luchessi AD, and Silbiger VN
- Subjects
- Adult, Aged, Alleles, Atherosclerosis complications, Atherosclerosis pathology, Coronary Artery Disease complications, Coronary Artery Disease genetics, Female, Gene Frequency, Genetic Predisposition to Disease, Genotype, Humans, Leukocytes cytology, Male, Middle Aged, Polymorphism, Single Nucleotide, Receptors, Immunologic metabolism, Coronary Artery Disease diagnosis, Leukocytes metabolism, RNA, Messenger metabolism, Receptors, Immunologic genetics
- Abstract
Members of the triggering receptor expressed on myeloid cells (TREM) family are associated with atherosclerosis risk and progression. TREML4 is upregulated in the early phase of acute coronary syndrome. We investigated the relationship between the mRNA expression of 13 genes in blood leukocytes, TREML4 polymorphisms, and coronary artery lesion extension (Friesinger index) in patients with coronary artery disease (CAD) (n = 137). TREML4 rs2803495 (A > G) and rs2803496 (T > C) variants and leukocyte mRNA expression were analysed by qRT-PCR. TREML4 expression was higher in patients with major coronary artery lesions than in subjects without or with low and intermediate lesions (p < 0.05). However, TREML4 polymorphisms were not associated with coronary lesion extent. Presence of the rs2803495 G allele was not associated with increased TREML4 mRNA expression. Patients carrying the rs2803496 C allele (TC/CC genotypes) were more likely to express TREML4 mRNA than non-C allele carriers (allele C: OR 7.3, and 95% CI 1.9-27.5, p = 0.03). In conclusion, increased TREML4 mRNA expression in blood leukocytes is influenced by gene polymorphisms and is associated with more severe coronary artery lesions, suggesting its potential as a biomarker of the extent of coronary lesions in patients with CAD.
- Published
- 2019
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24. New fluorescent rosamine chelator showing promising antibacterial activity against Gram-positive bacteria.
- Author
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Novais Â, Moniz T, Rebelo AR, Silva AMG, Rangel M, and Peixe L
- Subjects
- Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents chemistry, Dose-Response Relationship, Drug, Fluorescent Dyes chemical synthesis, Fluorescent Dyes chemistry, Heterocyclic Compounds, 3-Ring chemical synthesis, Heterocyclic Compounds, 3-Ring chemistry, Iron Chelating Agents chemical synthesis, Iron Chelating Agents chemistry, Microbial Sensitivity Tests, Molecular Structure, Rhodamines chemical synthesis, Rhodamines chemistry, Structure-Activity Relationship, Anti-Bacterial Agents pharmacology, Fluorescent Dyes pharmacology, Gram-Positive Bacteria drug effects, Heterocyclic Compounds, 3-Ring pharmacology, Iron Chelating Agents pharmacology, Rhodamines pharmacology
- Abstract
The restricted number of antibiotics to treat infections caused by common multidrug resistant bacterial pathogens in the clinical setting demands a continuous search for new molecules with antibacterial properties. Bacterial iron deprivation represents a promising alternative, being iron chelators an attractive class for drug design in which particular compounds seem to have antibacterial effect. In this work, we report the synthesis and characterization of a new fluorescent 3-hydroxy-4-pyridinone (3,4-HPO) iron chelator functionalized with a carboxyrosamine fluorophore (MRB20). The antibacterial activity of MRB20 was assessed against representative strains from clinically relevant Gram-positive and Gram-negative bacterial species and further compared with the inhibitory effect of a set of structurally related iron chelators including Deferiprone (1,2-dimethyl-3-hydroxy-4-pyridinone). Compounds exhibiting a promising minimal inhibitory concentration (MIC < 10 mg/L) were further tested against a wider range of bacterial genera and species (Staphylococcus spp. Enterococcus spp. Listeria monocytogenes, Bacillus spp.), including multidrug resistant bacteria. With the exception of the novel compound (MRB20), all chelators inhibited the strains assayed at very high concentrations [minimum inhibitory concentrations (MIC) ranging from 70 mg/L to >180 mg/L]. MRB20 revealed a good antibacterial activity (6.7-13.2 mg/L) against Gram-positive strains from different genera and species, including clinically relevant species (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium, Enterococcus faecalis), which might be eventually compatible with a therapeutic application or as adjuvant., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
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25. Circulating miRNAs in acute new-onset atrial fibrillation and their target mRNA network.
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da Silva AMG, de Araújo JNG, de Oliveira KM, Novaes AEM, Lopes MB, de Sousa JCV, Filho AAA, Luchessi AD, de Rezende AA, Hirata MH, and Silbiger VN
- Subjects
- Acute Disease, Adult, Aged, Atrial Fibrillation genetics, Circulating MicroRNA genetics, Female, Humans, Male, Middle Aged, Pilot Projects, RNA, Messenger genetics, Atrial Fibrillation blood, Circulating MicroRNA blood, Gene Regulatory Networks physiology, RNA, Messenger blood
- Abstract
Background: MicroRNAs (miRNAs) are involved in the pathogenesis of atrial fibrillation (AF), acting on development and progression. Our pilot study investigated the expression of six miRNAs and their miRNA-mRNA interactions in patients with acute new-onset AF, well-controlled AF, and normal sinus rhythm (controls)., Methods and Results: Plasma of acute new-onset AF patients (n = 5) was collected in the emergency room when patients presented with irregular and fast-atrial fibrillation rhythm. Samples from well-controlled AF (n = 16) and control (n = 15) patients were collected during medical appointments following an ECG. Expression of miR-21, miR-133a, miR-133b, miR-150, miR-328, and miR-499 was analyzed by real-time PCR. Ingenuity Pathway Analysis and the TargetScan database identified the top 30 mRNA targets of these miRNA, seeking the miRNA-mRNA interactions in cardiovascular process. Increased expression of miR-133b (1.4-fold), miR-328 (2.0-fold), and miR-499 (2.3-fold) was observed in patients with acute new-onset AF, compared with well-controlled AF and control patients. Decreased expression of miR-21 was seen in patients with well-controlled AF compared to those with acute new-onset AF and controls (0.6-fold). The miRNA-mRNA interaction demonstrated that SMAD7 and FASLG genes were the targets of miR-21, miR-133b, and miR-499 and were directly related to AF, being involved in apoptosis and fibrosis., Conclusion: The miRNAs had different expression profiles dependent on the AF condition, with higher expression in the acute new-onset AF than well-controlled AF. Clinically, this may contribute to an effective assessment for patients, leading to early detection of AF and monitoring to reduce the risk of other serious cardiovascular events., (© 2018 Wiley Periodicals, Inc.)
- Published
- 2018
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26. Role of Murine Complement Component C5 in Acute in Vivo Infection by Pathogenic Leptospira interrogans .
- Author
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de Castro ÍA, Bavia L, Fraga TR, Amano MT, Breda LCD, Granados-Martinez AP, da Silva AMG, Vasconcellos SA, and Isaac L
- Subjects
- Animals, Cytokines metabolism, Disease Models, Animal, Inflammation immunology, Interleukin-10, Kidney immunology, Kidney pathology, Leptospirosis blood, Leptospirosis pathology, Leukocytes, Liver immunology, Liver pathology, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Spleen immunology, Spleen pathology, Survival Analysis, Complement C5 immunology, Complement C5 physiology, Leptospira interrogans immunology, Leptospira interrogans pathogenicity, Leptospirosis immunology
- Abstract
Leptospirosis is considered one of the most important zoonosis worldwide. The activation of the Complement System is important to control dissemination of several pathogens in the host. Only a few studies have employed murine models to investigate leptospiral infection and our aim in this work was to investigate the role of murine C5 during in vivo infection, comparing wild type C57BL/6 (B6 C5
+/+ ) and congenic C57BL/6 (B6 C5-/- , C5 deficient) mice during the first days of infection. All animals from both groups survived for at least 8 days post-infection with pathogenic Leptospira interrogans serovar Kennewicki strain Fromm (LPF). At the third day of infection, we observed greater numbers of LPF in the liver of B6 C5-/- mice when compared to B6 C5+/+ mice. Later, on the sixth day of infection, the LPF population fell to undetectable levels in the livers of both groups of mice. On the third day, the inflammatory score was higher in the liver of B6 C5+/+ mice than in B6 C5-/- mice, and returned to normal on the sixth day of infection in both groups. No significant histopathological differences were observed in the lung, kidney and spleen from both infected B6 C5+/+ than B6 C5-/- mice. Likewise, the total number of circulating leukocytes was not affected by the absence of C5. The liver levels of IL-10 on the sixth day of infection was lower in the absence of C5 when compared to wild type mice. No significant differences were observed in the levels of several inflammatory cytokines when B6 C5+/+ and B6 C5-/- were compared. In conclusion, C5 may contribute to the direct killing of LPF in the first days of infection in C57BL/6 mice. On the other hand, other effector immune mechanisms probably compensate Complement impairment since the mice survival was not affected by the absence of C5 and its activated fragments, at least in the early stage of this infection.- Published
- 2018
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27. Correction: Ecstasy induces reactive oxygen species, kidney water absorption and rhabdomyolysis in normal rats. Effect of N-acetylcysteine and Allopurinol in oxidative stress and muscle fiber damage.
- Author
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de Bragança AC, Moreau RLM, de Brito T, Shimizu MHM, Canale D, de Jesus DA, Silva AMG, Gois PH, Seguro AC, and Magaldi AJ
- Abstract
[This corrects the article DOI: 10.1371/journal.pone.0179199.].
- Published
- 2018
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28. A new panel of SNPs to assess thyroid carcinoma risk: a pilot study in a Brazilian admixture population.
- Author
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Dos Santos ICC, Genre J, Marques D, da Silva AMG, Dos Santos JC, de Araújo JNG, Duarte VHR, Carracedo A, Torres-Español M, Bastos G, de Oliveira Ramos CC, Luchessi AD, and Silbiger VN
- Subjects
- Adult, Brazil, Female, Genetic Predisposition to Disease, Humans, Male, Middle Aged, Oligonucleotide Array Sequence Analysis, Pilot Projects, Retrospective Studies, Genetic Association Studies methods, Polymorphism, Single Nucleotide, Thyroid Neoplasms genetics
- Abstract
Background: Thyroid cancer is a common malignant disease of the endocrine system with increasing incidence rates over the last few decades. In this study, we sought to analyze the possible association of 45 single nucleotide polymorphisms (SNPs) with thyroid cancer in a population from Rio Grande do Norte, Brazil., Methods: Based on histological analysis by a pathologist, 80 normal thyroid specimens of tissue adjacent to thyroid tumors were obtained from the biobank at the Laboratory of Pathology of Liga Norte Riograndense Contra o Câncer, Natal, RN. Patient samples were then genotyped using the MassARRAY platform (Sequenon, Inc) followed by statistical analysis employing the SNPassoc package in R program. The genotypic frequencies of all 45 SNPs obtained from the International HapMap Project database and based on data from the ancestral populations of European and African origin were used to compose the control study group., Results: In our study, the following 9 SNPs showed significant differences in their frequency when comparing the study and control groups: rs3744962, rs258107, rs1461855, rs4075022, rs9943744, rs4075570, rs2356508, rs17485896, and rs2651339. Furthermore, the SNPs rs374492 C/T and rs258107 C/T were associated with a relative risk for thyroid carcinoma of 3.78 (p = 6.27 × 10e
-5 ) and 2.91 (p = 8.27 × 10e-5 ), respectively, after Bonferroni's correction for multiple comparisons., Conclusions: These nine polymorphisms could be potential biomarkers of predisposition to thyroid carcinoma in the population from Rio Grande do Norte. However, complementary studies including a control group with samples obtained from healthy subjects in Rio Grande do Norte state, should be conducted to confirm these results.- Published
- 2017
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29. Preparation of Luminescent Metal-Organic Framework Films by Soft-Imprinting for 2,4-Dinitrotoluene Sensing.
- Author
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Roales J, Moscoso FG, Gámez F, Lopes-Costa T, Sousaraei A, Casado S, Castro-Smirnov JR, Cabanillas-Gonzalez J, Almeida J, Queirós C, Cunha-Silva L, Silva AMG, and Pedrosa JM
- Abstract
A novel technique for the creation of metal-organic framework (MOF) films based on soft-imprinting and their use as gas sensors was developed. The microporous MOF material [Zn₂(bpdc)₂(bpee)] (bpdc = 4,4'-biphenyldicarboxylate; bpee = 1,2-bipyridylethene) was synthesized solvothermally and activated by removing the occluded solvent molecules from its inner channels. MOF particles were characterized by powder X-ray diffraction and fluorescence spectroscopy, showing high crystallinity and intense photoluminescence. Scanning electron microscope images revealed that MOF crystals were mainly in the form of microneedles with a high surface-to-volume ratio, which together with the high porosity of the material enhances its interaction with gas molecules. MOF crystals were soft-imprinted into cellulose acetate (CA) films on quartz at different pressures. Atomic force microscope images of soft-imprinted films showed that MOF crystals were partially embedded into the CA. With this procedure, mechanically stable films were created, with crystals protruding from the CA surface and therefore available for incoming gas molecules. The sensing properties of the films were assessed by exposing them to saturated atmospheres of 2,4-dinitrotoluene, which resulted in a substantial quenching of the fluorescence after few seconds. The soft-imprinted MOF films on CA/quartz exhibit good sensing capabilities for the detection of nitroaromatics, which was attributed to the MOF sensitivity and to the novel and more efficient film processing method based on soft-imprinting., Competing Interests: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.
- Published
- 2017
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30. Ecstasy induces reactive oxygen species, kidney water absorption and rhabdomyolysis in normal rats. Effect of N-acetylcysteine and Allopurinol in oxidative stress and muscle fiber damage.
- Author
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de Bragança AC, Moreau RLM, de Brito T, Shimizu MHM, Canale D, de Jesus DA, Silva AMG, Gois PH, Seguro AC, and Magaldi AJ
- Subjects
- Acetylcysteine pharmacology, Allopurinol pharmacology, Animals, Aquaporin 2 metabolism, Blotting, Western, Epithelial Sodium Channels metabolism, Glutathione metabolism, Hallucinogens toxicity, Kidney metabolism, Kidney Tubules, Collecting drug effects, Kidney Tubules, Collecting metabolism, Male, Muscle Fibers, Skeletal metabolism, Muscle Fibers, Skeletal pathology, Rats, Wistar, Rhabdomyolysis prevention & control, Solute Carrier Family 12, Member 1 metabolism, Thiobarbituric Acid Reactive Substances metabolism, Water metabolism, Free Radical Scavengers pharmacology, Kidney drug effects, Muscle Fibers, Skeletal drug effects, N-Methyl-3,4-methylenedioxyamphetamine toxicity, Oxidative Stress drug effects, Reactive Oxygen Species metabolism, Rhabdomyolysis chemically induced
- Abstract
Background: Ecstasy (Ec) use produces hyperthermia, excessive sweating, intense thirst, an inappropriate antidiuretic hormone secretion (SIADH) and a multisystemic toxicity due to oxidative stress (OS). Intense thirst induces high intake of pure water, which associated with SIADH, usually develops into acute hyponatremia (Hn). As Hn is induced rapidly, experiments to check if Ec acted directly on the Inner Medullary Collecting Ducts (IMCD) of rats were conducted. Rhabdomyolysis and OS were also studied because Ec is known to induce Reactive Oxygen Species (ROS) and tissue damage. To decrease OS, the antioxidant inhibitors N-acetylcysteine (NAC) and Allopurinol (Allo) were used., Methods: Rats were maintained on a lithium (Li) diet to block the Vasopressin action before Ec innoculation. AQP2 (Aquaporin 2), ENaC (Epitheliun Sodium Channel) and NKCC2 (Sodium, Potassium, 2 Chloride) expression were determined by Western Blot in isolated IMCDs. The TBARS (thiobarbituric acid reactive substances) and GSH (reduced form of Glutathione) were determined in the Ec group (6 rats injected with Ec-10mg/kg), in Ec+NAC groups (NAC 100mg/Kg/bw i.p.) and in Allo+Ec groups (Allo 50mg/Kg/i.p.)., Results: Enhanced AQP2 expression revealed that Ec increased water transporter expression, decreased by Li diet, but the expression of the tubular transporters did not change. The Ec, Ec+NAC and Allo+Ec results showed that Ec increased TBARS and decreased GSH, showing evidence of ROS occurrence, which was protected by NAC and Allo. Rhabdomyolysis was only protected by Allo., Conclusion: Results showed that Ec induced an increase in AQP2 expression, evidencing another mechanism that might contribute to cause rapid hyponatremia. In addition, they showed that NAC and Allo protected against OS, but only Allo decreased rhabdomyolysis and hyperthermia.
- Published
- 2017
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31. Preparation and Optimization of Fluorescent Thin Films of Rosamine-SiO2/TiO2 Composites for NO2 Sensing.
- Author
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Guillén MG, Gámez F, Suárez B, Queirós C, Silva AMG, Barranco Á, Sánchez-Valencia JR, Pedrosa JM, and Lopes-Costa T
- Abstract
The incorporation of a prototypical rosamine fluorescent dye from organic solutions into transparent and microstructured columnar TiO2 and SiO2 (MO2) thin films, prepared by evaporation at glancing angles (GAPVD), was evaluated. The aggregation of the adsorbed molecules, the infiltration efficiency and the adsorption kinetics were studied by means of UV-Vis absorption and fluorescence spectroscopies. Specifically, the infiltration equilibrium as well as the kinetic of adsorption of the emitting dye has been described by a Langmuir type adsorption isotherm and a pseudosecond order kinetic model, respectively. The anchoring mechanism of the rosamine to the MO2 matrix has been revealed by specular reflectance Fourier transform infrared spectroscopy and infiltration from aqueous solutions at different pH values. Finally, the sensing performance towards NO2 gas of optimized films has been assessed by following the changes of its fluorescence intensity revealing that the so-selected device exhibited improved sensing response compared to similar hybrid films reported in the literature.
- Published
- 2017
- Full Text
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