12/13/2023 0 Comments India ink staining whole blood![]() ![]() ![]() We hypothesized that with the availability of a florescent microscope in a clinical laboratory, acridine orange may be a more sensitive alternative to India ink light microscopy in the detection of Cryptococcus yeasts in CSF. ![]() In this study, we used acridine orange to detect cryptococcal yeasts in fresh whole CSF in comparison to India ink stain at serial time points during antifungal treatment in a clinical setting. Earlier work done by Cohen et al, 1984 showed no apparent advantage of acridine orange over india ink for the rapid identification of Cryptococcus neoformans using three laboratory strains. It emits yellow fluorescence when it binds RNA and green fluorescence when it binds DNA. It has been used to stain samples for viability staining, epifluorescence microscopy and is particularly useful in the rapid screening of sterile biological specimens from clinical and non-clinical materials. The poor sensitivity of India ink may lead to misdiagnosis hence increasing the burden and mortality due to cryptococcal meningitis in resource limited settings where it is still utilized.Īcridine orange is a fluorescence dye used to stain acidic vacuoles, DNA, and RNA in viable cells. The new point of care CrAg lateral flow assay is in fact more sensitive and user friendly in different sample types. However, many recent studies done in sub-Saharan Africa in clinical settings demonstrated low and poor sensitivity of India ink in the diagnosis of cryptococcal meningitis. It is still being used in some resource limited settings of sub-Saharan Africa where the burden due to cryptococcal meningitis is highest. India ink has over time been used in the rapid diagnosis of cryptococcal meningitis using cerebrospinal fluid (CSF) among AIDS patients. However, detection of the cryptococcal antigen (CrAg) in CSF, serum and whole blood has recently gained more popularity with better sensitivity. Culture of cerebrospinal fluid (CSF) is the gold standard for diagnosis of CM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Ĭryptococcal meningitis (CM) is the most common cause of adult meningitis in Africa accounting for 15%–25% of AIDS-related deaths with majority of the cases registered in sub-Saharan Africa. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the paper and its Supporting Information files.įunding: Financial support for this research was provided by the National Institutes of Health (R01NS086312, T32AI055433 R25TW009345), Grand Challenges Canada (S4 0296-01), and United Kingdom Medical Research Council (MR/M007413/1). Received: ApAccepted: JPublished: July 27, 2017Ĭopyright: © 2017 Kwizera et al. Rodrigues, OSWALDO CRUZ FOUNDATION, BRAZIL Studies of other components of the ink are now in progress.Citation: Kwizera R, Akampurira A, Williams D, Boulware DR, Meya DB, on behalf of the ASTRO-CM Study Team (2017) Acridine orange fluorescent microscopy is more sensitive than India ink light microscopy in the rapid detection of cryptococcosis among CrAg positive HIV patients. Preliminary studies indicate that the suppression of dye excretion by the liver is not due to the carbon content of the ink. It is felt that the literature of "blockade" should be studied with such sources of error in mind. Thus, prolonged retention of foreign materials in the blood stream cannot be cited to prove "blockade of the reticulo-endothelial system" unless one can rule out such peculiar reactions on the part of excretory organs. There is no evidence that any of the retention is due to defective activity on the part of the phagocytes. The fact that much of the carbon of the ink is promptly taken up by the phagocytes would lead one to suspect that they were saturated with foreign materials, or "blocked" against the entrance of dye, but it is shown that the ink causes a remarkable inhibition of the excretion of dye into the bile, and this alone seems to account for the longer retention of dye in the blood stream. The injection of a small amount of India ink into the blood stream results in lowering the rate at which the dye disappears from circulation. The rate at which the dye leaves the blood stream is determined in large part by the action of these phagocytic cells, but the excretion of dye into the bile is also in part responsible for the loss of dye from the plasma. When brilliant vital red is injected into the blood stream of dogs much of it is slowly taken up into numerous phagocytes scattered throughout the tissues ("reticulo-endothelial system" of Aschoff). ![]()
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