Molecular docking analysis of proflavin with the Wnt pathway targets for OSCC

Wnt signaling pathway plays a critical role in tumor progression and metastasis of various cancer types. Therefore, it is of interest to document the molecular docking analysis of proflavin with the Wnt pathway targets (GSK3β, β-catenin, and VIM) for oral squamous cell carcinoma (OSCC). These results suggest that targeting the wnt signaling downstream targets with proflavine might leads to the better outcome for therapeutic outcome for the inhibition of invasion and metastasis in oral squamous cell carcinoma.

Feasibility of moxifloxacin and proflavine dual fluorescence imaging for detecting gastrointestinal neoplastic lesions: A prospective study

OBJECTIVES

High-contrast and high-resolution imaging techniques would enable real-time sensitive detection of the gastrointestinal lesions. This study aimed to investigate the feasibility of novel dual fluorescence imaging using moxifloxacin and proflavine in the detection of neoplastic lesions of the human gastrointestinal tract.

METHODS

Patients with the colonic and gastric neoplastic lesions were prospectively enrolled. The lesions were biopsied with forceps or endoscopically resected. Dual fluorescence imaging was performed by using custom axially swept wide-field fluorescence microscopy after topical moxifloxacin and proflavine instillation. Imaging results were compared with both confocal imaging with cell labeling and conventional histological examination.

RESULTS

Ten colonic samples (one normal mucosa, nine adenomas) from eight patients and six gastric samples (one normal mucosa, five adenomas) from four patients were evaluated. Dual fluorescence imaging visualized detail cellular structures. Regular glandular structures with polarized cell arrangement were observed in normal mucosa. Goblet cells were preserved in normal colonic mucosa. Irregular glandular structures with scanty cytoplasm and dispersed elongated nuclei were observed in adenomas. Goblet cells were scarce or lost in the colonic lesions. Similarity analysis between moxifloxacin and proflavine imaging showed relatively high correlation values in adenoma compared with those in normal mucosa. Dual fluorescence imaging showed good detection accuracies of 82.3% and 86.0% in the colonic and the gastric lesions, respectively.

CONCLUSIONS

High-contrast and high-resolution dual fluorescence imaging was feasible for obtaining detail histopathological information in the gastrointestinal neoplastic lesions. Further studies are needed to develop dual fluorescence imaging as an in vivo real-time visual diagnostic method.

Excited-State Dynamics of Proflavine after Intercalation into DNA Duplex

Proflavine is an acridine derivative which was discovered as one of the earliest antibacterial agents, and it has been proven to have potential application to fields such as chemotherapy, photobiology and solar-energy conversion. In particular, it is well known that proflavine can bind to DNA with different modes, and this may open addition photochemical-reaction channels in DNA. Herein, the excited-state dynamics of proflavine after intercalation into DNA duplex is studied using femtosecond time-resolved spectroscopy, and compared with that in solution. It is demonstrated that both fluorescence and the triplet excited-state generation of proflavine were quenched after intercalation into DNA, due to ultrafast non-radiative channels. A static-quenching mechanism was identified for the proflavine-DNA complex, in line with the spectroscopy data, and the excited-state deactivation mechanism was proposed.

Atto 465 Derivative Is a Nuclear Stain with Unique Excitation and Emission Spectra Useful for Multiplex Immunofluorescence Histochemistry

Multiplex immunofluorescence (mIF) is an effective technique for the maximal visualization of multiple target proteins in situ. This powerful tool is mainly limited by the spectral overlap of the currently available synthetic fluorescent dyes. The fluorescence excitation wavelengths ranging between 405 and 488 nm are rarely used in mIF imaging and serve as a logical additional slot for a fluorescent probe. In the present study, we demonstrate that the addition of 2,3,4,5,6-pentafluoroaniline to Atto 465 NHS ester, creating Atto 465-pentafluoroaniline (Atto 465-p), generates a bright nuclear stain in the violet-blue region of the visible spectrum. This allows the 405 nm excitation and emission, classically used for nuclear counterstains, to be used for the detection of another target protein. This increases the flexibility of the mIF panel and, with appropriate staining and microscopy, enables the quantitative analysis of at least six targets in one tissue section. (J Histochem Cytochem XX: XXX-XXX, XXXX).

Methylene Blue and Proflavine as Intraarterial Marker for Functional Perforazome-Comparative Study

Methylene blue (MB) is both a dye and a medicine known and used for a long time including as lymphatic tracer in melanoma and breast cancer for revealing sentinel lymph nodes. Proflavine (PRO) is an acriflavine dye, used as bacteriostatic disinfectant against many gram-positive bacteria that was also successfully applied to evaluate morphopathological changes in tissues. This study was performed on a group of twenty-eight Wistar rats and had as its main objective the in vivo evaluation of the use of MB and PRO as perforator tracers. The two dyes proved to be effective functional perforasome tracers with medium inflammatory infiltrate in the skin of the island perforator flap which heals perfectly at 14 days with complete absence of the inflammatory reaction. At the same injected amount, PRO seems to determine a greater inflammatory reaction compared with MB, but in smaller concentration, the inflammatory response is absent in the case of PRO. In conclusion, both substances tested within this in vivo study are good functional perforasome tracers, but PRO has the advantage of the absence of inflammatory reaction when using lower concentrations, while preserving unalerted its efficiency as tracer.

Comparative Study Regarding the Properties of Methylene Blue and Proflavine and Their Optimal Concentrations for In Vitro and In Vivo Applications

Methylene blue and proflavine are fluorescent dyes used to stain nucleic acid from the molecular level to the tissue level. Already clinically used for sentinel node mapping, detection of neuroendocrine tumors, methemoglobinemia, septic shock, ifosfamide-induced encephalopathy, and photodynamic inactivation of RNA viruses, the antimicrobial, anti-inflammatory, and antioxidant effect of methylene blue has been demonstrated in different in vitro and in vivo studies. Proflavine was used as a disinfectant and bacteriostatic agent against many gram-positive bacteria, as well as a urinary antiseptic involved in highlighting cell nuclei. At the tissue level, the anti-inflammatory effects of methylene blue protect against pulmonary, renal, cardiac, pancreatic, ischemic-reperfusion lesions, and fevers. First used for their antiseptic and antiviral activity, respectively, methylene blue and proflavine turned out to be excellent dyes for diagnostic and treatment purposes. In vitro and in vivo studies demonstrated that both dyes are efficient as perfusion and tissue tracers and permitted to evaluate the minimal efficient concentration in different species, as well as their pharmacokinetics and toxicity. This review aims to identify the optimal concentrations of methylene blue and proflavine that can be used for in vivo experiments to highlight the vascularization of the skin in the case of a perforasome (both as a tissue tracer and in vascular mapping), as well as their effects on tissues. This review is intended to be a comparative and critical presentation of the possible applications of methylene blue (MB) and proflavine (PRO) in the surgical field, and the relevant biomedical findings from specialized literature to date are discussed as well.

Proflavine/acriflavine derivatives with versatile biological activities

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.

Qualitative and quantitative comparison of colonic microendoscopy image features to histopathology

Colorectal cancer is the second leading cause of cancer deaths in the United States, affecting more than 130,000 Americans every year¹. Determining tumor margins prior to surgical resection is essential to providing optimal treatment and reducing recurrence rates. Colorectal cancer recurrence can occur in up to 20% of cases, commonly within three years after curative treatment. Typically, when colorectal cancers are resected, a margin of normal tissue on both sides of the tumor is required. The minimum margin required for colon cancer is 5 cm and for the lower rectum 2 cm. However, usually more normal tissue is taken on both sides of the tumor because the blood supply to the entire segment is removed with the surgery and therefore the entire segment must be removed. Anastomotic recurrences may result from inadequate margins. Pathologists look at the margins to ensure that there is no residual tumor and this is usually documented in the pathology report. We have developed a portable, point-of-care fiber bundle microendoscopy imaging system for detection of abnormalities in colonic epithelial microstructure. The system comprises a laptop, a modified fiber bundle image guide with a 1mm active area diameter and custom Lab VIEW interface, and is approved for imaging surgically resected colon tissue at the University of Arkansas for Medical Sciences. The microendoscopy probe provides high-resolution images of superficial epithelial histology in real-time to assist surgical guidance and to localize occult regions of dysplasia which may not be visible. Microendoscopy images of freshly resected human colonic epithelium were acquired using the microendoscopy device and subsequently mosaicked using custom post-processing software. Architectural changes in the glands were mapped to histopathology H&E slides taken from the precise location of the microendoscopy images. Qualitatively, glandular distortion and placement of image guide was used to map normal and dysplastic areas of the colonic tumor and surrounding region from microendoscopy images to H&E slides. Quantitative metrics for correlating images were also explored and were obtained by analyzing glandular diameter and spatial distribution as well as image texture.

Design and validation of a diffuse reflectance and spectroscopic microendoscope with poly(dimethylsioxane)-based phantoms

Many cases of epithelial cancer originate in basal layers of tissue and are initially undetected by conventional microendoscopy techniques. We present a bench-top, fiber-bundle microendoscope capable of providing high resolution images of surface cell morphology. Additionally, the microendoscope has the capability to interrogate deeper into material by using diffuse reflectance and broadband diffuse reflectance spectroscopy. The purpose of this multimodal technique was to overcome the limitation of microendoscopy techniques that are limited to only visualizing morphology at the tissue or cellular level. Using a custom fiber optic probe, high resolution surface images were acquired using topical proflavine to fluorescently stain non-keratinized epithelia. A 635 nm laser coupled to a 200 μm multimode fiber delivers light to the sample and the diffuse reflectance signal was captured by a 1 mm image guide fiber. Finally, a tungsten-halogen lamp coupled to a 200 μm multimode fiber delivers broadband light to the sample to acquire spectra at source-detector separations of 374, 729, and 1051 μm. To test the instrumentation, a high resolution proflavine-induced fluorescent image of resected healthy mouse colon was acquired. Additionally, five monolayer poly(dimethylsiloxane)-based optical phantoms with varying absorption and scattering properties were created to acquire diffuse reflectance profiles and broadband spectra.

Studies on the interactions of 3,6-diaminoacridine derivatives with human serum albumin by fluorescence spectroscopy

This study reports the preparation and investigation of the modes of binding of the two symmetric 3,6-diaminoacridine derivatives obtained from proflavine, which are 3,6-diphenoxycarbonyl aminoacridine and 3,6-diethoxycarbonyl aminoacridine to human serum albumin (HSA). The interaction of HSA with the derivatives was investigated using fluorescence quenching and ultraviolet-visible absorption spectra at pH 7.2 and different temperatures. The results suggest that the derivatives used can interact strongly with HSA and are the formation of HSA-derivative complexes and hydrophobic interactions as the predominant intermolecular forces in stabilizing for each complex. The Stern-Volmer quenching constants, binding constants, binding sites and corresponding thermodynamic parameters ΔH, ΔS and ΔG were calculated at different temperatures. The binding distance (r) ~ 3 nm between the donor (HSA) and acceptors (3,6-diethoxycarbonyl aminoacridine, 3,6-diphenoxycarbonyl aminoacridine and proflavine) was obtained according to Förster's non-radiative energy transfer theory. Moreover, the limit of detection and limit of quantification of derivatives were calculated in the presence of albumin.

High-resolution microendoscope images of middle ear cholesteatoma and surrounding tissue: evaluation of interobserver concordance

OBJECTIVE

Investigate how accurately otolaryngologists could differentiate between images obtained with high-resolution microendoscopy (HRME) of ex vivo cholesteatoma specimens and surrounding middle ear epithelium.

STUDY DESIGN

HRME images of surgically resected cholesteatoma and middle ear epithelium were obtained and otolaryngologists classified these images.

SETTING

Tertiary medical center.

SUBJECTS AND METHODS

Resected cholesteatoma and middle ear epithelium were stained with a contrast agent, proflavine, and HRME images were captured. Specimens were sent for standard histopathology and compared with HRME images. Quality-controlled images were used to assemble a training set. After viewing training images, otolaryngologists without prior cholesteatoma HRME experience reviewed and classified test images.

RESULTS

Ten cholesteatoma and 9 middle ear specimens were collected, of which 17 representative cholesteatoma and 19 middle ear epithelium images were extracted for a testing set. Qualitative analysis for concordance between HRME images and histological images yielded a strong correlation between modalities. The mean accuracy of all reviewers in correctly identifying images was 95% (95% confidence interval [CI], 92%-98%). The sensitivity to correctly detect cholesteatoma images was 98% (95% CI, 93%-100%), and the specificity was 92% (95% CI, 87%-97%). The Fleiss kappa interrater reliability score was 0.83, (95% CI, 0.77-0.89).

CONCLUSIONS

Medical professionals can quickly be trained to accurately distinguish between HRME images of cholesteatoma and normal middle ear epithelium, both of which have distinct imaging characteristics. Real-time HRME optical imaging can potentially improve the results of otologic surgery by allowing for extirpation of cholesteatomas while eliminating residual disease.

Synthesis, characterization and cytotoxicity studies of palladium(II)-proflavine complexes

An investigation of the reaction of Pd(II) complexes with proflavine (3,6-diaminoacridine) resulted in the isolation of the compounds [Pd(terpy)(proflavine)](NO(3))(HSO(4))*3H(2)O, 1, (terpy = 2,2':6',2″-terpyridine), [Pd(en)(proflavineH))](NO(3))(SO(4)), 2, (en = ethylenediamine), and [Pd(proflavineH)Cl(2)](SO(4))(0.5)*H(2)O, 3. They have been isolated and characterized by NMR, IR, and electro-spray ionization mass spectrometry techniques and by elemental analyses. The proflavine was bonded to the Pd(II) through the endocyclic nitrogen in 1, but through the proflavine NH(2) in 2. Compound 3 appeared to be polymeric in the solid state with a 1:1 mole ratio of Pd(II):proflavine. Upon solution of 3 in DMSO, two unique species were formed. In one species the Pd(II) was bonded to two proflavines through the endocyclic nitrogen (1:2 mole ratio) and in the other species, a Pd(II) was bonded to each NH(2) group of a single proflavine (2:1 mole ratio). Molecular modeling of the equilibrium geometry by Spartan 8 produced structures which were consistent with the experimental data on the solutions of the three compounds. In vitro cytotoxicity testing against two breast cancer cell lines and one ovarian cancer cell line showed that compounds 1 and 3 had significant activity.

Photoreduction of NADP + sensitized by synthetic pigment systems

Two synthetic pigment systems capable of enzymatically photoreducing NADP(+) are described. One system contains proflavine; the other, acridine. The complete system consists of ethylene diamine tetraacetic acid (EDTA), proflavine (or acridine), ferredoxin-NADP reductase (EC 1.6.99.4), and NADP(+). The two pigments initiate the photoreduction of NADP(+) in different portions of the electromagnetic spectrum. Proflavine photosensitizes in the visible portion; acridine, in the ultraviolet. Neither proflavine nor acridine is structurally related to chlorophyll. The acridine system has the attractive property that the enzyme, ferredoxin-NADP reductase, is the only component of the system that absorbs appreciably in the visible region of the spectrum.

Quinacrine, a chromosome stain specific for deoxyadenylate-deoxythymidylaterich regions in DNA

Fluorescence of quinacrine in the presence of different polynucleotides was studied to attempt to identify the specific nucleotides responsible for the fluorescence of stained chromosome preparations. A marked enhancement of fluorescence was seen in the presence of bihelical polynucleotides, such as poly(dA-dT), poly(dA).poly(dT), and poly(rA).poly(rU), but not in the presence of single-stranded polynucleotides, such as poly(dA), poly(dT), poly(rA), or poly(rU) alone. The higher was the GC content of natural DNAs, the more they quenched. Quenching was also seen with poly(dG) or poly(rG) alone, but not with poly(dC) or poly(rC) alone. Native and denatured DNA were both effective in quenching fluorescence. Thus, a bihelical conformation is not required for fluorescence quenching. Nearly all of these properties are shared with proflavine. In contrast, acridine orange, which stains most areas of chromosome preparations, shows enhanced fluorescence in the presence of all members of a series of natural DNAs. These data suggest that base-pairs composed of AT (rather than GC) residues are responsible for the observed fluorescence of specific chromosome regions after treatment with quinacrine, and support the proposal of Ellison and Barr (Chromosoma, in press) that the highly localized quinacrine fluorescence in their cytological preparations reflects the presence of DNA that has a high (A + T)/(G + C) ratio.