Sections cut at 6 -8 microns. Stain with 0.5% Congo Red in 50% alcohol for 10 minutes. What is the exposition of the story of sinigang? Photo 2 – Congo red under polarising microscope X10. This website is intended for pathologists and laboratory personnel but not for patients. We welcome suggestions or questions about using the website. Corrections? This aggregation phenomenon is more prevalent in high Congo red concentrations, at high salinity and/or low pH. Although these aggregates are present under various sizes and shapes, the "ribbon-like micelles" of a few molecules seem to be the predominant form (even if the "micelle" term is not an entirely appropriate name for it). Bennhold 1 found that congo red, if carefully prepared, could be injected intravenously without danger. Design by, Evaluating Eosin-Stained Frozen Section Slides Using…, Light Chain Proximal Tubulopathy Amyloid Proximal…. The objective of this study was to assess the congo red biodegradation and detoxification by Aspergillus niger . The main special stain used for amyloid detection is Congo Red.  The reason for this is that the Congo red dye used in the stain is highly selective for amyloid deposits, which can lead to amyloidosis and also alzheimers. ©2020 Arkana Laboratories. Furthermore, Congo red may also be used to induce expression of the type III secretion system of Shigella flexneri, bringing about the secretion of IpaB and IpaC, which form translocation pores within host cell membrane, allowing effector proteins to pass through and alter the host cell's biochemistry. Which of the following lesions should be negative for Congo red? In this case, granular brown lipofuscin pigment can be seen in the atrophic muscle fibers under routine light microscopy. In histology and microscopy, Congo red is used for staining in amyloidosis, and for the cell walls of plants and fungi, and for the outer membrane of Gram-negative bacteria. This attachment is achieved by the non-polar hydrogen bonds formed between the Congo red and amyloid deposit. Below is the technique for performing this stain. In the laboratory this can be used for diagnosis, for example of amyloidosis or alzheimers. Alcohol 50 % Reagent alcohol ~50 ml Deionized water ~50 ml. The dye was a major commercial success for AGFA. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. How do you put grass into a personification? Our editors will review what you’ve submitted and determine whether to revise the article. What are the disadvantages of primary group? [2] Once of economic significance, Congo red has fallen into disuse as have all benzidine-derived dyes, owing to their carcinogenic activity. I. Congo Red solution Sodium chloride 2 g: Dissolved in deionized water 20 ml Congo Red powder 0.5 g: Suspended in 100 % absolute alcohol 80 ml Combine the two solutions (store at room temperature for months) II. Is there a way to search all eBay sites for different countries at once? The apple green birefringence seen here, proves that it is infact amyloid that is been visualised rather than anything else. Copyright © 2020 Multiply Media, LLC. Updates? How will understanding of attitudes and predisposition enhance teaching? © Copyright PathologyOutlines.com, Inc. Click. Alcohol 70 % Let us know if you have suggestions to improve this article (requires login). It is still used in histology to stain tissues for microscopic examination, and to serve as an acid-base indicator, since it turns red in the presence of alkalies and blue when exposed to acids. Congo red: ( kong'gō red ), [C.I. This property gives Congo red a metachromatic property as a dye, both in strongly acidic solutions and with strongly acidophilic tissue. Congo Red, the first direct dye, was discovered in 1883 by Paul Bottinger, who was working as a dye chemist for the Friedrich Bayer Company in Ebersfeld, Germany (Garg and Nigam, 1981; Linke, 2006). Congo red, first of the synthetic dyestuffs of the direct type, that is, not requiring application of a mordant (a substance such as tannin or alum used to fix the colour to cotton fibres). Since this color change is an approximate inverse of that of litmus, it can be used with litmus paper in a simple parlor trick: add a drop or two of Congo red to both an acid solution and a base solution. However, we cannot answer medical or research questions or give advice. When did organ music become associated with baseball? The first use of Congo red came in 1883 by an accident discovery by Paul Bottiger in Elberfeld, Germany. Congo red dye is a synthetic reactive water soluble dye: used in medicine (as a biological stain) and as an indicator since it turns from red-brown (in basic medium) to blue in acidic one. Gattuso: Differential Diagnosis in Surgical Pathology, 2nd Edition, 2010, Case Rep Gastrointest Med 2015;2015:320120, Uversky: Bio-nanoimaging - Protein Misfolding and Aggregation, 1st Edition, 2014, Oral Surg Oral Med Oral Pathol 1988;66:466, Hyalinizing trabecular adenoma of the thyroid gland, Congo red is an organic compound used for staining, Congo red stain is the gold standard for the demonstration of, It is used to evaluate the presence and extent of amyloidosis in different organs, Common diseases for Congo red stain include, Amyloidosis is a rare disease characterized by the deposition of insoluble misfolded proteins in various tissues and organs, This conformational change is responsible for abnormal folding of the light chain, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils (, Amyloid fibril Congo red complex demonstrates green birefringence owing to the parallel alignment of dye molecules along the β pleated sheath, Mostly used for systemic or localized amyloidosis, such as AL amyloid seen in plasma cell dyscrasias, AA amyloid associated with inflammatory conditions, Aβ amyloid fibrils in Alzheimer disease and TTR amyloidosis due to either familial gene mutation or wild type protein, formerly called senile amyloidosis, Amyloids can be detected in the kidney, liver, heart, brain and other organs, Amyloid deposits in tissue exhibit a deep red or salmon color, whereas elastic tissue remains pale pink, When viewed under polarized light, amyloid deposits exhibit apple green birefringence, Thickness of the section is critical (8 - 10 μm) (, Rotating the slide or the polarizing filter is important for visualizing the birefringence (, Improved sensitivity is reported by using a metallurgical polarized microscope (, Tissue elements such as collagen, elastin and others may display birefringence of varying colors that may be misinterpreted as amyloid (, Do not mistake the blue-green of collagen for the lime green of amyloid, Evaluate the presence and extent of systemic or localized amyloidosis, Amyloid heart disease is the main prognostic factor with an unfavorable outcome (, Nerve, gastrointestinal tract, lung and soft tissue (, Kidney in longterm inflammatory disorder (, Kidneys, retroperitoneal lymphoma mass, blood vessels and adrenal glands in, Secondary corneal amyloidosis in keratoconus (, Amyloid insulin bodies at an insulin injection site (, Primary central nervous system nonamyloidogenic light chain deposition disease (, Bone marrow in a patient with multiple myeloma, Kidney in a patient with systemic lupus erythematosus, Liver in a patient with systemic light chain amyloidosis. The lipofuscin pigment is also autofluorescent, showing a white-yellow color under fluorescence microscopy. The company was not interested in this bright red color, so he filed the patent under his own name and sold it to the AGFA company of Berlin. Due to a color change from blue to red at pH 3.0–5.2, Congo red can be used as a pH indicator. Why don't libraries smell like bookstores? See if your geographic knowledge points north or south in this journey through Africa. The surface of the agar is subsequently flooded with a 1 mg/ml solution of Congo red for 15 min. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply. How long can you keep a fresh turkey in the fridge before it has to be cooked? CONGO RED STAIN PROTOCOL (MODIFIED FROM JOHNS HOPKINS) PRINCIPLE: This stain is used for the visual detection of amyloid in muscle and nerve fresh frozen sections in patients who have amyloidosis. Regions of the agar where the hydrolysis of CMC has occurred are clear, whereas intact CMC will retain the Congo red dye. 22120] An acid direct cotton dye, it is absorbed by amyloid and induces green fluorescence to amyloid in polarized light; used as a laboratory aid in the diagnosis of amyloidosis, as a histologic stain, and as an indicator (pH 3, blue-violet, to pH 5, red…