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1.
Molecules ; 26(16)2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34443446

RESUMO

A novel series of proflavine ureas, derivatives 11a-11i, were synthesized on the basis of molecular modeling design studies. The structure of the novel ureas was obtained from the pharmacological model, the parameters of which were determined from studies of the structure-activity relationship of previously prepared proflavine ureas bearing n-alkyl chains. The lipophilicity (LogP) and the changes in the standard entropy (ΔS°) of the urea models, the input parameters of the pharmacological model, were determined using quantum mechanics and cheminformatics. The anticancer activity of the synthesized derivatives was evaluated against NCI-60 human cancer cell lines. The urea derivatives azepyl 11b, phenyl 11c and phenylethyl 11f displayed the highest levels of anticancer activity, although the results were only a slight improvement over the hexyl urea, derivative 11j, which was reported in a previous publication. Several of the novel urea derivatives displayed GI50 values against the HCT-116 cancer cell line, which suggest the cytostatic effect of the compounds azepyl 11b-0.44 µM, phenyl 11c-0.23 µM, phenylethyl 11f-0.35 µM and hexyl 11j-0.36 µM. In contrast, the novel urea derivatives 11b, 11c and 11f exhibited levels of cytotoxicity three orders of magnitude lower than that of hexyl urea 11j or amsacrine.


Assuntos
Entropia , Proflavina/síntese química , Ureia/síntese química , Fenômenos Químicos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Cinética , Masculino , Modelos Moleculares , Proflavina/química , Proflavina/farmacologia , Ureia/química , Ureia/farmacologia
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 247: 119114, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33166781

RESUMO

The interaction between xanthene dye eosin Y and double stranded DNA has been studied by spectrophotometry. The conventional titration study does not show the interaction in the eosin Y - DNA system. Therefore, the competitive binding assay was carried out. The DNA-targeted ligands proflavine and methylene blue were used as competitors. Multivariate curve resolution - alternative least squares method (MCR-ALS) was applied to analyze the spectrophotometric titration data. The experimental binding isotherms were fitted by Scatchard and McGee equations. The binding constant of eosin Y with DNA was found to be 1.7·104 M-1. It is shown that the competitive binding assay requires consideration of heteroassociation for the correct determination of ligand-DNA binding parameters.


Assuntos
DNA , Proflavina , Ligação Competitiva , Amarelo de Eosina-(YS) , Espectrofotometria
3.
J Biomol Struct Dyn ; 38(6): 1590-1597, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31057051

RESUMO

The binding of proflavine, an acriflavine derivative, with the RNA polynucletodide polyadenylic acid-polyuridylic acid is investigated here to understand the structural and thermodynamic basis of the binding process. Such binding data are crucial for designing viable theraperutic agents. Spectroscopic studies clearly suggest a strong binding interaction between proflavine and polyadenylic acid-polyuridylic acid leading to efficient energy transfer between the poly AU base pairs and proflavine. The stoichiometry of proflavine polyadenylic acid-polyuridylic acid binding was independently estimated by continuous variation analysis of Job. An intercalative binding model is envisaged for the binding from hydrodynamic studies. Circular dichroism experiments revealed that the binding induced conformational changes in the RNA, and also led to induction of optical activity in the bound dye molecules. The binding affinity of the complex was deduced to be (6.57 ± 0.75) 105 M-1 at (298.15 ± 0.10) K from isothermal titration calorimetry experiment. Positive entropy and negative enthalpy changes characterized the complexation. The binding was observed to be weaker both at higher temperatures and increased [Na+]. The affinity of binding decreased with increasing [Na+]. When the Gibbs energy was parsed between polyelectrolytic and nonpolyelectropytic components, it surprisingly revealed a higher role for the non-polyelectrolytic forces. These results present new data for developing RNA targeted ligands.Communicated by Ramaswamy H. Sarma.


Assuntos
Polinucleotídeos , Proflavina , Calorimetria , Dicroísmo Circular , Conformação de Ácido Nucleico , Poli A , RNA , Termodinâmica
4.
J Appl Toxicol ; 40(1): 64-71, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31222780

RESUMO

Proflavine derivatives are extremely interesting chemotherapeutic agents, which have shown promising pharmaceutical potential due to their wide range of biological activities. This review summarizes the current state of research into the anticancer, antimicrobial, antimalarial and antileishmanial properties of these attractive compounds. Our attention has focused on new classes of proflavine conjugates, which display significant levels of anticancer activity. Highly promising cytotoxic properties have been identified in proflavine conjugates with imidazolidinones, ureas and thioureas. In particular, proflavine-dialkyldithioureas displayed substantial cytotoxic effect against the human leukemia HL-60 cells with IC50 values from 7.2 to 34.0 µm. As well, palladium complexes with proflavine ligand have important biologic activity. The LC50 values of these complexes were significantly lower than that of cisplatin against the SK-BR-3 cell line.


Assuntos
Acriflavina/farmacologia , Anti-Infecciosos/farmacologia , Antineoplásicos/farmacologia , Proflavina/farmacologia , Acriflavina/análogos & derivados , Acriflavina/toxicidade , Animais , Anti-Infecciosos/toxicidade , Antineoplásicos/toxicidade , Relação Dose-Resposta a Droga , Humanos , Concentração Inibidora 50 , Estrutura Molecular , Proflavina/análogos & derivados , Proflavina/toxicidade , Relação Estrutura-Atividade
5.
J Phys Chem B ; 123(51): 10904-10914, 2019 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-31671261

RESUMO

Intercalation into DNA is the interaction mode of some anthracycline antibiotics. Recently, the molecular mechanism of this process was explored using the static free energy landscape. Here we explore the dynamical effects in the intercalation of proflavine into DNA by calculating the transmission coefficient κ-providing a measure of the departure from transition state theory for the reaction rate constant-by examination of the recrossing events at the transition state. For that purpose, we first found the accurate transition state of this complex system-as judged by a committor analysis-using a set of all-atom simulations of total length 6.3 ms. In a subsequent calculation of the transmission coefficient κ in another extensive set of simulations the small value κ = 0.1 was found, indicating a significant departure from TST. Comparison of this result with Grote-Hynes and Kramers theories shows that neither theory is able to capture this complex system's recrossing events; the source of this striking failure is discussed, as are related aspects of the mechanism. This study suggests that, for biomolecular processes similar to this, dynamical effects essential for the process are complex in nature and require novel approaches for their elucidation.


Assuntos
Antineoplásicos/química , DNA/química , Substâncias Intercalantes/química , Proflavina/química , Entropia , Cinética , Modelos Moleculares , Termodinâmica
6.
Biosensors (Basel) ; 9(2)2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31013753

RESUMO

Development of technologies for rapid screening of DNA secondary structure thermal stability and the effects on stability for binding of small molecule drugs is important to the drug discovery process. In this report, we describe the capabilities of an electrochemical, microdevice-based approach for determining the melting temperatures (Tm) of electrode-bound duplex DNA structures. We also highlight new features of the technology that are compatible with array development and adaptation for high-throughput screening. As a foundational study to exhibit device performance and capabilities, melting-curve analyses were performed on 12-mer DNA duplexes in the presence/absence of two binding ligands: diminazene aceturate (DMZ) and proflavine. By measuring electrochemical current as a function of temperature, our measurement platform has the ability to determine the effect of binding ligands on Tm values with high signal-to-noise ratios and good reproducibility. We also demonstrate that heating our three-electrode cell with either an embedded microheater or a thermoelectric module produces similar results. The ΔTm values we report show the stabilizing ability of DMZ and proflavine when bound to duplex DNA structures. These initial proof-of-concept studies highlight the operating characteristics of the microdevice platform and the potential for future application toward other immobilized samples.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , Técnicas Eletroquímicas/métodos , Diminazena/análogos & derivados , Diminazena/química , Ligantes , Proflavina/química , Temperatura de Transição
7.
Photochem Photobiol ; 94(6): 1308-1313, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29981148

RESUMO

Proflavine is an acridine dye used with high-resolution microendoscopy for in vivo diagnostic evaluation of cervical epithelial cells. However, there are concerns that even short-term exposure of cervical tissue to dilute proflavine may increase cervical cancer risk. We performed a retrospective analysis of women referred for colposcopy to Barretos Cancer Hospital comparing the risk of cervical disease progression in those whose cervical tissue was (n = 232) or was not exposed (n = 160) to proflavine. Patients in both groups underwent treatment and follow-up based on histopathologic results and per the local standards of care. Progression of disease was evaluated by comparing histopathology from the initial visit to the worst subsequent histopathology result from all follow-up visits. Mean duration of follow-up was 18.7 and 20.1 months for the proflavine-exposed and controls groups, respectively. There were no significant differences in disease progression from normal/CIN1 to CIN2/3 or from any initial diagnosis to invasive cancer between the proflavine exposed and control groups overall. Risks of cervical dysplasia progression observed in this study are in agreement with those of the natural history of cervical cancer. Our results suggest that cervical exposure to dilute proflavine does not increase the risk of cervical precancer and cancer.


Assuntos
Neoplasia Intraepitelial Cervical/diagnóstico por imagem , Colo do Útero/diagnóstico por imagem , Colposcopia/métodos , Meios de Contraste/administração & dosagem , Proflavina/administração & dosagem , Neoplasias do Colo do Útero/diagnóstico por imagem , Adulto , Neoplasia Intraepitelial Cervical/metabolismo , Neoplasia Intraepitelial Cervical/patologia , Colo do Útero/metabolismo , Colo do Útero/patologia , Progressão da Doença , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Risco , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia
8.
Mol Pharmacol ; 93(6): 592-600, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29650538

RESUMO

Many compounds inhibit tetrameric and pseudo-tetrameric cation channels by associating with the central cavity located in the middle of the membrane plane. They traverse the ion conduction pathway from the intracellular side and through access to the cavity. Previously, we reported that the bacteriostatic agent, proflavine, preferentially blocked a subset of inward rectifier K+ (Kir) channels. However, the development of the inhibition of Kir1.1 by the compound was obviously different from that operating in Kir3.2 as a pore blocker. To gain mechanistic insights into the compound-channel interaction, we analyzed its chemical specificity, subunit selectivity, and voltage dependency using 13 different combinations of Kir-channel family members and 11 proflavine derivatives. The Kir-channel family members were classified into three groups: 1) Kir2.2, Kir3.x, Kir4.2, and Kir6.2Δ36, which exhibited Kir3.2-type inhibition (slow onset and recovery, irreversible, and voltage-dependent blockage); 2) Kir1.1 and Kir4.1/Kir5.1 (prompt onset and recovery, reversible, and voltage-independent blockage); and 3) Kir2.1, Kir2.3, Kir4.1, and Kir7.1 (no response). The degree of current inhibition depended on the combination of compounds and channels. Chimera between proflavine-sensitive Kir1.1 and -insensitive Kir4.1 revealed that the extracellular portion of Kir1.1 is crucial for the recognition of the proflavine derivative acrinol. In conclusion, preferential blockage of Kir-channel family members by proflavine derivatives is based on multiple modes of action. This raises the possibility of designing subunit-specific inhibitors.


Assuntos
Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização/antagonistas & inibidores , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Proflavina/farmacologia , Animais , Humanos , Camundongos , Ratos
9.
Cancer Prev Res (Phila) ; 10(10): 563-570, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28765195

RESUMO

The 5-year survival rate for patients with oral cancer remains low, in part because diagnosis often occurs at a late stage. Early and accurate identification of oral high-grade dysplasia and cancer can help improve patient outcomes. Multimodal optical imaging is an adjunctive diagnostic technique in which autofluorescence imaging is used to identify high-risk regions within the oral cavity, followed by high-resolution microendoscopy to confirm or rule out the presence of neoplasia. Multimodal optical images were obtained from 206 sites in 100 patients. Histologic diagnosis, either from a punch biopsy or an excised surgical specimen, was used as the gold standard for all sites. Histopathologic diagnoses of moderate dysplasia or worse were considered neoplastic. Images from 92 sites in the first 30 patients were used as a training set to develop automated image analysis methods for identification of neoplasia. Diagnostic performance was evaluated prospectively using images from 114 sites in the remaining 70 patients as a test set. In the training set, multimodal optical imaging with automated image analysis correctly classified 95% of nonneoplastic sites and 94% of neoplastic sites. Among the 56 sites in the test set that were biopsied, multimodal optical imaging correctly classified 100% of nonneoplastic sites and 85% of neoplastic sites. Among the 58 sites in the test set that corresponded to a surgical specimen, multimodal imaging correctly classified 100% of nonneoplastic sites and 61% of neoplastic sites. These findings support the potential of multimodal optical imaging to aid in the early detection of oral cancer. Cancer Prev Res; 10(10); 563-70. ©2017 AACR.


Assuntos
Detecção Precoce de Câncer/métodos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias Bucais/diagnóstico por imagem , Boca/diagnóstico por imagem , Imagem Multimodal/métodos , Imagem Óptica/métodos , Algoritmos , Biópsia , Meios de Contraste/administração & dosagem , Humanos , Hiperplasia/diagnóstico por imagem , Hiperplasia/patologia , Boca/patologia , Boca/cirurgia , Neoplasias Bucais/patologia , Neoplasias Bucais/cirurgia , Lesões Pré-Cancerosas/diagnóstico por imagem , Lesões Pré-Cancerosas/patologia , Proflavina/administração & dosagem , Estudos Prospectivos , Sensibilidade e Especificidade , Adulto Jovem
10.
J Appl Toxicol ; 37(10): 1132-1139, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28370171

RESUMO

Acridines possess two characteristics that have led many researchers to consider the agents interesting targets for future development as potential farmacophores: the planar acridine skeleton, which is able to intercalate into DNA, and the intense fluorescence of the agents. This review offers a study of the multifunctional character of acridines and the synthesis of novel acridine derivatives, with particular focus being placed on isothiocyanates and their congeners, e.g. thioureas, isothioureas, quaternary ammonium salts and platinum/gold conjugates. The review provides an overview of the structure, spectral properties, DNA binding and biological activity of acridinylthiourea congeners. These acridinylthiourea derivatives display significant cytotoxic activities against different types of cancer cell lines at micromolar concentrations. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Acridinas/síntese química , Acridinas/farmacologia , Dano ao DNA/efeitos dos fármacos , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Humanos , Isotiocianatos/síntese química , Isotiocianatos/farmacologia , Proflavina/síntese química , Proflavina/farmacologia , Relação Estrutura-Atividade , Tioureia/síntese química , Tioureia/farmacologia
11.
Anal Bioanal Chem ; 409(11): 2813-2819, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28188352

RESUMO

A novel pretreatment-free method involving laser desorption postionization (LDPI) coupled with time-of-flight mass spectrometry (MS) was developed for the monitoring of proflavine level in rat whole blood. It comprises a protocol for dosing via intravenous administration and collection of whole blood, followed by direct LDPI-MS analysis without any sample pretreatment. An intense ion signal at m/z 209 was observed from whole blood without any interference signals, except some background signals below m/z 100. The calibration curve was established with use of 9-phenylacridine as the internal standard for proflavine determination from the plotting of the peak ratios of proflavine to the internal standard, with a correlation coefficient (R 2) greater than 0.99. The limit of detection was estimated to be 0.48 pmol/mm2 and the quantification range was 0.5-16.5 µg/mL for proflavine. In addition, only a minimal matrix effect was observed, as expected from considerations of the desorption and ionization mechanism. Interday and intraday accuracy and precision were calculated to be within 13% and 82-114%, respectively. Estimated concentrations of proflavine residue in whole blood were also successfully obtained at selected time points after dosing. The proposed method is simple, low cost, and sensitive, and should be seen as a complementary method for monitoring drug levels in blood. Graphical Abstract Monitoring proflavine levels in rat whole blood at different time points using laser desorption postionization mass spectrometry (LDPI-MS).


Assuntos
Análise Química do Sangue/métodos , Monitoramento de Medicamentos/métodos , Proflavina/sangue , Manejo de Espécimes/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Animais , Injeções Intravenosas , Masculino , Proflavina/administração & dosagem , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
12.
Nucleic Acids Res ; 45(1): 198-205, 2017 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-27694309

RESUMO

Acridine dyes, including proflavine and acriflavine, were commonly used as antiseptics before the advent of penicillins in the mid-1940s. While their mode of action on pathogens was originally attributed to their DNA intercalating activity, work in the early 1970s suggested involvement of the host immune responses, characterized by induction of interferon (IFN)-like activities through an unknown mechanism. We demonstrate here that sub-toxic concentrations of a mixture of acriflavine and proflavine instigate a cyclic-GMP-AMP (cGAMP) synthase (cGAS)-dependent type-I IFN antiviral response. This pertains to the capacity of these compounds to induce low level DNA damage and cytoplasmic DNA leakage, resulting in cGAS-dependent cGAMP-like activity. Critically, acriflavine:proflavine pre-treatment of human primary bronchial epithelial cells significantly reduced rhinovirus infection. Collectively, our findings constitute the first evidence that non-toxic DNA binding agents have the capacity to act as indirect agonists of cGAS, to exert potent antiviral effects in mammalian cells.


Assuntos
Acriflavina/farmacologia , Antivirais/farmacologia , Fatores Imunológicos/farmacologia , Substâncias Intercalantes/farmacologia , Proteínas de Membrana/genética , Nucleotidiltransferases/genética , Proflavina/farmacologia , Animais , Brônquios/efeitos dos fármacos , Brônquios/imunologia , Brônquios/virologia , Linhagem Celular Transformada , Chlorocebus aethiops , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/imunologia , Células Epiteliais/virologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/imunologia , Fibroblastos/virologia , Regulação da Expressão Gênica , Células HEK293 , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Humanos , Proteínas de Membrana/agonistas , Proteínas de Membrana/imunologia , Camundongos , Nucleotídeos Cíclicos/imunologia , Nucleotídeos Cíclicos/metabolismo , Nucleotidiltransferases/imunologia , Cultura Primária de Células , Rhinovirus/efeitos dos fármacos , Rhinovirus/crescimento & desenvolvimento , Transdução de Sinais , Células Vero , Carga Viral/efeitos dos fármacos
13.
J Pharm Sci ; 105(12): 3615-3625, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27776769

RESUMO

Pillar[n]arenes are a new family of nanocapsules that have shown application in a number of areas, but because of their poor water solubility their biomedical applications are limited. Recently, a method of synthesizing water-soluble pillar[n]arenes was developed. In this study, carboxylated pillar[n]arenes (WP[n], n = 6 or 7) have been examined for their ability to form host-guest complexes with compounds relevant to drug delivery and biodiagnostic applications. Both pillar[n]arenes form host-guest complexes with memantine, chlorhexidine hydrochloride, and proflavine by 1H nuclear magnetic resonance and modeling. Binding is stabilized by hydrophobic effects within the cavities, and hydrogen bonding and electrostatic interactions at the portals. Encapsulation within WP[6] results in the complete and efficient quenching of proflavine fluorescence, giving rise to "on" and "off" states that have potential in biodiagnostics. The toxicity of the pillar[n]arenes was examined using in vitro growth assays with the OVCAR-3 and HEK293 cell lines. The pillar[n]arenes are relatively nontoxic to cells except at high doses and after prolonged continuous exposure. Overall, the results show that there could be a potentially large range of medical applications for carboxylated pillar[n]arene nanocapsules.


Assuntos
Substâncias Macromoleculares/metabolismo , Modelos Moleculares , Preparações Farmacêuticas/metabolismo , Compostos de Amônio Quaternário/metabolismo , Células HEK293 , Humanos , Substâncias Macromoleculares/química , Memantina/metabolismo , Preparações Farmacêuticas/química , Proflavina/química , Proflavina/metabolismo , Compostos de Amônio Quaternário/química
14.
J Photochem Photobiol B ; 165: 42-50, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27768952

RESUMO

Interaction of proflavine with hemoglobin (Hgb) was studied employing spectroscopy, calorimetry, and atomic force microscopy. The equilibrium constant was found to be of the order 104M-1. The quenching of Hgb fluorescence by proflavine was due to the complex formation. Calculation of the molecular distance (r) between the donor (ß-Trp37 of Hgb) and acceptor (proflavine) suggested that energy can be efficiently transferred from the ß-Trp37 residue at the α1ß2 interface of the protein to the dye. Proflavine induced significant secondary structural changes in Hgb. Synchronous fluorescence studies showed that proflavine altered the microenvironment around the tryptophan residues to a greater extent than the tyrosine residues. Circular dichroism spectral studies showed that proflavine caused significant reduction in the α-helical content of Hgb. The esterase activity assay further complemented the circular dichroism data. The Soret band intensity of Hgb decreased upon complexation. Differential scanning calorimetry and circular dichroism melting results revealed that proflavine induced destabilization of Hgb. The binding was driven by both positive entropy and negative enthalpy. Atomic force microscopy studies revealed that the essential morphological features of hemoglobin were retained in the presence of proflavine. Overall, insights on the photophysical aspects and energetics of the binding of proflavine with Hgb are presented.


Assuntos
Hemoglobinas/metabolismo , Proflavina/metabolismo , Fenômenos Biofísicos , Calorimetria , Dicroísmo Circular , Humanos , Microscopia de Força Atômica , Ligação Proteica , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
15.
Neuropharmacology ; 109: 18-28, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27236080

RESUMO

The overexpression of Kir3.2, a subunit of the G protein-gated inwardly rectifying K(+) channel, is implicated in some of the neurological phenotypes of Down syndrome (DS). Chemical compounds that block Kir3.2 are expected to improve the symptoms of DS. The purpose of this study is to develop a cell-based screening system to identify Kir3.2 blockers and then investigate the mode of action of the blocker. Chemical screening was carried out using a K(+) transporter-deficient yeast strain that expressed a constitutively active Kir3.2 mutant. The mode of action of an effective blocker was electrophysiologically analyzed using Kir channels expressed in Xenopus oocytes. Proflavine was identified to inhibit the growth of Kir3.2-transformant cells and Kir3.2 activity in a concentration-dependent manner. The current inhibition was strong when membrane potentials (Vm) was above equilibrium potential of K(+) (EK). When Vm was below EK, the blockage apparently depended on the difference between Vm and [K(+)]. Furthermore, the inhibition became stronger by lowering extracellular [K(+)]. These results indicated that the yeast strain serves as a screening system to isolate Kir3.2 blockers and proflavine is a prototype of a pore blocker of Kir3.2.


Assuntos
Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/antagonistas & inibidores , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/fisiologia , Inibidores do Crescimento/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Proflavina/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Relação Dose-Resposta a Droga , Feminino , Inibidores do Crescimento/química , Camundongos , Bloqueadores dos Canais de Potássio/química , Proflavina/química , Xenopus laevis
16.
Phys Chem Chem Phys ; 18(15): 10383-91, 2016 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-27030311

RESUMO

Proflavine is a small molecule that intercalates into DNA and, thereby, acts as an anticancer agent. Intercalation of proflavine is shown to be a two-step process in which the first step is believed to be the formation of a pre-intercalative outside bound state. Experimental studies so far have been unable to capture the nature of the outside bound state. However, the sub-millisecond timescale observed in fluorescence kinetic experiments is often attributed to the binding of proflavine outside of DNA. Here, we have performed molecular dynamics simulations with multiple proflavine molecules to study the structure and dynamics of the formation of the outside bound state of DNA at different ion concentrations. We observed that the timescale of the outside bound state formation is, at least, five orders of magnitude faster (in nanoseconds) than the experimentally reported timescale (sub-milliseconds) attributed to binding outside DNA. Moreover, we also observed the stacked arrangement of proflavine all around DNA, which is different from the experimentally predicted stacking arrangement perpendicular to the helical axis of DNA in the close vicinity of the phosphate groups. This study, therefore, provides insight into the molecular structure and dynamics of the pre-intercalative outside bound state and will help in understanding the overall intercalation mechanism.


Assuntos
DNA/química , Proflavina/química , Dimerização , Cinética , Estrutura Molecular , Espectrometria de Fluorescência
17.
Chem Commun (Camb) ; 52(31): 5436-9, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-27009481

RESUMO

Proflavine, a known intercalator of DNA and RNA, promotes duplex formation by nucleic acids with natural and non-natural backbones that otherwise form duplexes with low thermal stability, and even some that show no sign of duplex formation in the absence of proflavine. These findings demonstrate the potential for intercalators to be used as cofactors for the assembly of rationally designed nucleic acid structures, and could provide fundamental insights regarding intercalation of natural nucleic acid duplexes.


Assuntos
Substâncias Intercalantes/farmacologia , Conformação de Ácido Nucleico/efeitos dos fármacos , Ácidos Nucleicos/química , Proflavina/farmacologia , Materiais Biomiméticos/química , DNA/química , Substâncias Intercalantes/química , Modelos Moleculares , Proflavina/química , RNA/química
18.
J Oncol Pharm Pract ; 22(1): 21-5, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25113309

RESUMO

BACKGROUND AND PURPOSE: Proflavine hemisulfate solution is a fluorescence contrast agent to visualize cell nuclei using high-resolution optical imaging devices such as the high-resolution microendoscope. These devices provide real-time imaging to distinguish between normal versus neoplastic tissue. These images could be helpful for early screening of oral cancer and its precursors and to determine accurate margins of malignant tissue for ablative surgery. Extemporaneous preparation of proflavine solution for these diagnostic procedures requires preparation in batches and long-term storage to improve compounding efficiency in the pharmacy. However, there is a paucity of long-term stability data for proflavine contrast solutions. METHODS: The physical and chemical stability of 0.01% (10 mg/100 ml) proflavine hemisulfate solutions prepared in sterile water was determined following storage at refrigeration (4-8℃) and room temperature (23℃). Concentrations of proflavine were measured at predetermined time points up to 12 months using a validated stability-indicating high-performance liquid chromatography method. RESULTS: Proflavine solutions stored under refrigeration were physically and chemically stable for at least 12 months with concentrations ranging from 95% to 105% compared to initial concentration. However, in solutions stored at room temperature increased turbidity and particulates were observed in some of the tested vials at 9 months and 12 months with peak particle count reaching 17-fold increase compared to baseline. Solutions stored at room temperature were chemically stable up to six months (94-105%). CONCLUSION: Proflavine solutions at concentration of 0.01% were chemically and physically stable for at least 12 months under refrigeration. The solution was chemically stable for six months when stored at room temperature. We recommend long-term storage of proflavine solutions under refrigeration prior to diagnostic procedure.


Assuntos
Meios de Contraste/química , Estabilidade de Medicamentos , Soluções Farmacêuticas/química , Proflavina/química , Armazenamento de Medicamentos/métodos , Neoplasias Bucais/tratamento farmacológico , Soluções Farmacêuticas/uso terapêutico , Proflavina/uso terapêutico , Refrigeração/métodos
19.
Talanta ; 143: 19-26, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26078123

RESUMO

The direct electrochemical detection of synthetic DNA and native 16S rRNA fragments isolated from Escherichia coli is described. Oligonucleotides are detected via selective post-labeling of double stranded DNA and DNA-RNA duplexes with a biotinylated intercalator that enables high-specific binding of a streptavidin/alkaline phosphatase conjugate. The alkaline phosphatase catalyzes formation of p-aminophenol that is subsequently oxidized at the underlying gold electrode and hence enables the detection of complementary hybridization of the DNA capture strands due to the enzymatic signal amplification. The hybridization assay was performed on microarrays consisting of 32 individually addressable gold microelectrodes. Synthetic DNA strands with sequences representing six different pathogens which are important for the diagnosis of urinary tract infections could be detected at concentrations of 60 nM. Native 16S rRNA isolated from the different pathogens could be detected at a concentration of 30 fM. Optimization of the sensing surface is described and influences on the assay performance are discussed.


Assuntos
Fosfatase Alcalina/metabolismo , Técnicas Biossensoriais/métodos , DNA/análise , Substâncias Intercalantes/química , RNA Ribossômico 16S/análise , Biotinilação , DNA/síntese química , DNA/química , Sondas de DNA/química , Eletroquímica , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Limite de Detecção , Análise de Sequência com Séries de Oligonucleotídeos , Proflavina/química , RNA Ribossômico 16S/química , Estreptavidina/metabolismo
20.
PLoS One ; 10(5): e0125598, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25962131

RESUMO

Proflavine hemisulfate, an acridine-derived fluorescent dye, can be used as a rapid stain for cytologic examination of biological specimens. Proflavine fluorescently stains cell nuclei and cytoplasmic structures, owing to its small amphipathic structure and ability to intercalate DNA. In this manuscript, we demonstrated the use of proflavine as a rapid cytologic dye on a number of specimens, including normal exfoliated oral squamous cells, cultured human oral squamous carcinoma cells, and leukocytes derived from whole blood specimens using a custom-built, portable, LED-illuminated fluorescence microscope. No incubation time was needed after suspending cells in 0.01% (w/v) proflavine diluted in saline. Images of proflavine stained oral cells had clearly visible nuclei as well as granular cytoplasm, while stained leukocytes exhibited bright nuclei, and highlighted the multilobar nature of nuclei in neutrophils. We also demonstrated the utility of quantitative analysis of digital images of proflavine stained cells, which can be used to detect significant morphological differences between different cell types. Proflavine stained oral cells have well-defined nuclei and cell membranes which allowed for quantitative analysis of nuclear to cytoplasmic ratios, as well as image texture analysis to extract quantitative image features.


Assuntos
Meios de Contraste , Corantes Fluorescentes , Teste de Papanicolaou/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Proflavina , Linhagem Celular Tumoral , Humanos , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Teste de Papanicolaou/instrumentação
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