Fluorescein as a topical fluorescent contrast agent for quantitative microendoscopic inspection of colorectal epithelium

Abstract

Abstract:Fiber bundle microendoscopic imaging of colorectal tissue has shown promising results, for both qualitative and quantitative analysis. A quantitative image quality control and image feature extraction algorithm was previously designed for quantitative image feature analysis of proflavine-stained ex vivo colorectal tissue. We investigated fluorescein as an alternative topical stain. Images of ex vivo porcine, caprine, and human colorectal tissue were used to compare microendoscopic images of tissue topically stained with fluorescein and proflavine solutions. Fluorescein was shown to be comparable for automated crypt detection, with an average crypt detection sensitivity exceeding 90% using a combination of three contrast limit pairs. Godbold, E. Zhou, J. Mitcham, R. Richards-Kortum, and S. Anandasabapathy, "In vivo diagnostic accuracy of high-resolution microendoscopy in differentiating neoplastic from non-neoplastic colorectal polyps: a prospective study," Am. J. Gastroenterol. 109(1), 68-75 (2014 Ten Kate, P. Fockens, and J. Bergman, "Chromoendoscopy and narrow-band imaging compared with highresolution magnification endoscopy in Barrett's esophagus," Gastroenterology 134(3), 670-679 (2008). 17. R. A. Wall and J. K. Barton, "Fluorescence-based surface magnifying chromoendoscopy and optical coherence tomography endoscope," J.

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

“…MB was used for the first time by Ehrlich, in 1886, to stain the nervous tissue by injecting it intravenously into a living animal [11]. As a non-toxic biological stain, with an affinity for mucosal tissue [9], nowadays, MB is used for nervous tissue and endocrine gland identification during surgery [19]. Meanwhile, PRO is used to highlight the cell nuclei and enable direct visualization of cellular morphology without removing the tissue, on behalf of its property as a topical contrast agent [36].…”

“…Different authors reported the use of both dyes for diagnostic procedures including: in vivo confocal laser endomicroscopy [37,38], in vivo microscopy to identify Barrett's esophagus [39], pathological changes in oral mucosa [40], colon [9], stomach [41], duodenum, upper gastrointestinal tract [41] and central airway, cervical tissue [35,42], cervix [35], sarcoma [43], urinary fistula [44], sentinel node (SN)'s, head and neck cancers [45], breast cancer [17], and gastrointestinal and thyroid surgery [10]. Apart from MB and PRO's ability to stain nuclei, the latter also stains non-specifically the membranes of adipocyte cells, making it possible to identify adipocytes without using a contrast agent [43].…”

“…The reason why the use of PRO on human subjects is limited in the United States is that it is considered a dye with high hazardous potential and a mutagenic nature. Given these assumptions, to date, PRO has mainly been used as an investigational drug [9].…”

“…As hetero-tricyclic dyes ( Figure 1), both substances have florescent proprieties which are used in many clinical and experimental applications. When MB, a promethazine drug, is intended for use in in vivo tests, its ability to form bonds with blood cells and easily penetrate inside the cell is taken in consideration [10]. This is supported by its concentration levels in blood that have been found to be four to five times higher than in plasma [11].…”

“…MB has other applications due to its antimicrobial, anti-inflammatory, and antioxidant effects [10]. In the last decade it has been successfully used in several pathologies [5], as mentioned in Table 1.…”