Primary localized cutaneous amyloidosis
Dimitris Rigopoulos, Alexander C. Katoulis in Hyperpigmentation, 2017
Amyloid stains pink with H&E and metachromatically with chrystal violet and methyl violet. It stains selectively with Congo red. Amyloid stained by Congo red gives an apple-green birefringence when viewed in polarized light. Amyloid gives a bright yellow-green fluorescence with thioflavine T. Some studies report that crystal violet is more reliable than Congo red in sun-damaged skin, which sometimes gives false-positive staining with Congo red. The cotton dye Pagoda red no. 9, used as a variant of the Congo red method, is said to be more specific for amyloid than Congo red. The amyloid in LA and MA stains with the monoclonal antibody EKH4, which recognizes 50 kDa neutral and acidic keratin. It also stains with the keratin antibody AE1. The antikeratin antibody EAB-903, which recognizes 57 and 66 kDa keratin peptides, reacts with the amyloid deposits in both LA and MA, but not with the amyloid in systemic amyloidosis. Immunoglobulins, particularly IgM, and C3 complement are found in cutaneous amyloid deposits. Most of the studies have been confined to the localized cutaneous forms. Amyloid is thought to act like a filamentous sponge with nonspecific trapping of the immunoglobulins and complement.26–29
Rare forms of interstitial lung disease
Muhunthan Thillai, David R Moller, Keith C Meyer in Clinical Handbook of Interstitial Lung Disease, 2017
Amyloidosis refers to a group of inherited or acquired conditions that result from extracellular deposition of insoluble fibrillar protein of β-pleated sheet structure that allows the characteristic binding of Congo red stain. Amyloid can form from a variety of precursor proteins. The three most common forms of amyloidosis are primary amyloidosis (immunoglobulin light chains, AL), transthyretin amyloidosis (ATTR), and amyloid A protein amyloidosis (AA) (3,4).
Aggressive Light Chain Amyloidosis Cases have Unstable Immunoglobulin Light Chains
Gilles Grateau, Robert A. Kyle, Martha Skinner in Amyloid and Amyloidosis, 2004
Amyloidoses are an important group of protein deposition disorders in which normally soluble protein aggregates to form insoluble extracellular amyloid fibrils (1). Amyloid fibrils and/or their precursors are suggested to lead to cell death and tissue degeneration. These amyloid fibrils are characterized by their ability to bind histological dyes such as Congo Red and Thioflavine T, and they present a cross-β sheet structure by X-ray fibril diffraction.
Correlations between pore textures of activated carbons and Langmuir constants – case studies on methylene blue and congo red adsorption
Published in Toxin Reviews, 2022
Fadina Amran, Muhammad Abbas Ahmad Zaini
Congo red (CR) was discovered as a first direct dye by Paul Bottinger in 1883 (Linke 2006). The chromophore groups of direct dyes are azo, stibene, oxazine and phthalocyanine. Congo red is an anionic diazo dye which consists of –NH2 and –SO3 functional groups. It exists as brownish-red crystalline solid, stable in air and has high solubility in water. At pH ranging from 2 to 12, the color changes from dark blue to red. Congo red is usually used as pH indicator, and in the diagnosis of amyloidosis and free hydrochloric acid test in gastric contents (Rehman et al.2012). Besides, it is a common dye in textile industry because it has high affinity toward cellulose fiber (Asses et al.2018). However, it is known to be metabolized into benzidine, a human carcinogen and mutagen. Thus, it has been forbidden in many countries (Chattopadhyay 2011). Table 1 summarizes the physicochemical properties of methylene blue and congo red.
Effect of reserpine on Pseudomonas aeruginosa quorum sensing mediated virulence factors and biofilm formation
Published in Biofouling, 2018
Debaprasad Parai, Malabika Banerjee, Pia Dey, Arindam Chakraborty, Ekramul Islam, Samir Kumar Mukherjee
Congo red is a dye which binds to the biofilm EPS (Rollefson et al. 2011). Reserpine showed a notable reduction in EPS in the form of a slime layer observed around the colonies (Figure 4A). While the average diameters of the vehicle control colonies were measured to be 21 mm, they were reduced to 8 and 7 mm after the IC50 and IC80 treatments, respectively. However, the colony diameter did not vary notably at IC25 (20 mm). Pellicles were formed at the air–liquid interface of a standing liquid culture of P. aeruginosa PAO1 (Figure 4C). In this experiment, the untreated vehicle control and IC25 treated tubes showed the formation of robust pellicle with greenish pigments, but it visibly decreased after IC50 and IC80 treatments (Figure 4B and C).
Phylogenetic Group B2 Expressed Significant Biofilm Formation among Drug Resistant Uropathogenic Escherichia coli
Published in Libyan Journal of Medicine, 2021
Saima Javed, Zulfiqar Ali Mirani, Zaid Ahmed Pirzada
As there is no standardized method for biofilm detection and because of multifactorial nature of biofilm we could not depend on single method. Therefore in the current study the ability of UPEC to produce biofilm was assessed by Congo-red agar, microtiter biofilm assay, glass slides in static un-induced condition and SEM analysis. Moreover, strain property, culture media and methodology have great impact on outcome of biofilm formation, in vitro conditions. CRA is a rapid method for screening of slime production in bacteria that gives clue about biofilm-forming ability of the strain. Congo red binds directly with polysaccharides and form colour complex [25]. Biofilm on glass slide has given the best results, especially in case of strains that are weak/non biofilm producers on CRA and MTP. This might be due to greater surface area available for biofilm growth on glass slides. SEM provides the facility to observe biofilm pattern closely in natural forms.
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