What is Congo red used for?

Congo red was formerly used to dye cotton but has been superseded by dyes more resistant to light and to washing. 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.

What is Congo red disease?

Fibrillary and immunotactoid glomerulonephritis are very uncommon non-amyloid (Congo red negative) forms of Ig-associated kidney disease with abnormal tissue deposits from fibrils. Similar to LCDD, they usually present with a glomerulonephritis picture (hematuria and proteinuria, hypertension, and kidney impairment).

Is Congo red harmful?

Congo Red is an azo dye, it is toxic to many organisms and is a suspected carcinogen and mutagen.

Why is it called Congo red?

Congo red was introduced in Berlin in 1885 as the first of the economically lucrative direct textile dyes. … Conclusions: The Congo red stain was named Congo for marketing purposes by a German textile dyestuff company in 1885, reflecting geopolitical current events of that time.

Who discovered Congo Red?

Paul Bottinger 1 Chemistry of direct dyes. 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).

Is Congo Red a basic dye?

Congo red is an acid-base indicator dye. … Such solvents may also change the aggregation or solvation states of the dye, with consequent modification in the colour of tissue components.

What is the main cause of amyloidosis?

In general, amyloidosis is caused by the buildup of an abnormal protein called amyloid. Amyloid is produced in your bone marrow and can be deposited in any tissue or organ.

What is Congo red test?

Congo red stain is the gold standard for the demonstration of amyloid in tissue sections. The amyloid fibril Congo red complex demonstrates apple green birefringence using polarized light microscopy.

What is lichen amyloidosis?

Lichen amyloidosis is a chronic pruritic skin disorder characterized by amyloid deposition in the skin without evidence of visceral involvement. First described by Gutmann in 1928,¹ it is seen most frequently in Southeast Asia,² China,³ and South America.

Is Congo Red flammable?

Not flammable or combustible. Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Why is Congo Red Blue?

Congo red is also used as a pH indicator. The color transition is between pH 3.0 and 5.0. Below a pH of 3.0 (very acidic solutions), the indicator is blue. … When a cellulose sponge is soaked in a Congo red solution, the dye becomes permanently bonded to the cellulose fibers.

What color does Congo not like?

Congo would be given a piece of paper and, in conditions of considerable concentration, would begin painting. The choice of colours was his, red being a particular favourite, blue being a colour he disliked.

How does the Congo Red stain work?

Congo red demonstrates the accumulation of amyloid. With light microscopy it stains a pink or light red colour and shows green birefringence with polarized light. With rhodamine or Texas fluorescence the deposits show enhanced red fluorescence.

What color is Congo?

Congo Green is a deep, pure, peacock green with a seafoam undertone. It is a perfect paint color for all the walls of a dining room or living room or an accent wall. Pair it with fresh yellows and lively pinks for a South-of-the-Border appeal.

How many azo groups are in the Congo red?

Congo red is one of the best known and used azo dyes which has two azo bonds (-N=N-) chromophore in its molecular structure.

Is Congo red light sensitive?

Congo red, despite having lower sensitivity, is the standard agent used to identify amyloid in tissues. While the apple-green birefringence seen under crossed polarized light is specific for amyloid material, staining with Congo red is technically difficult resulting in inconsistent staining.

Can Congo red be used instead of safranin?

2) Would congo red, another pink-red stain, be a suitable replacement for safranin in the Gram stain, why or why not? No, because Congo red is a acidic (negative) stain, and the Gram stain uses two basic stains (positive stains).

Is Congo red soluble in water?

It is an azo dye. Congo red is water-soluble, yielding a red colloidal solution; its solubility is greater in organic solvents. However, the use of Congo red has long been abandoned, primarily because of its carcinogenic properties.

What is Congo red stain bacteria?

In histology, the Congo red is used for staining amyloidosis, other amyloids in cell wall of plants, fungi and outer membrane of Gram Negative bacteria. Congo red is a synthetic dye, used for the differential staining of elastic fibers.

What is the life expectancy of a person with amyloidosis?

On average, people with familial ATTR amyloidosis live for 7 to 12 years after they get their diagnosis, according to the Genetic and Rare Diseases Information Center. A study published in the journal Circulation found that people with wild-type ATTR amyloidosis live an average of about 4 years after diagnosis.

What organs affect amyloidosis?

It most commonly affects the kidneys, liver and spleen. Hereditary amyloidosis (familial amyloidosis). This inherited disorder often affects the nerves, heart and kidneys. It most commonly happens when a protein made by your liver is abnormal.

How do you prevent amyloidosis?

There is no prevention for amyloidosis. However, the secondary forms of amyloidosis can be prevented by treating the underlying diseases that are associated with inflammation. Genetic counseling can be beneficial in familial amyloidosis.

What type of dye is Congo red?

diazo dye Congo Red is the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid; a diazo dye that is red in alkaline solution and blue in acid solution and used especially as an indicator and as a biological stain. Congo Red is an indicator dye that is blue-violet at pH 3.0 and red at pH 5.0.

What does amyloidosis look like on the skin?

Lichen amyloidosis is characterized by severely itchy patches of thickened skin with multiple small bumps. The patches are scaly and reddish brown in color. These patches usually occur on the shins but can also occur on the forearms, other parts of the legs, and elsewhere on the body.

Is lichen amyloidosis fatal?

A skin biopsy should be reserved for evolving lesions. Lichen amyloidosis is a chronic condition without potential for malignant transformation or increase in mortality. Treatment is not required but can be employed for symptomatic or cosmetic complaints.

Does lichen amyloidosis spread?

Intensely pruritic hyperkeratotic papules that may coalesce to form gray to brown plaques with distribution on the anterior tibiae being a common site of involvement is a common presentation. However, spreading to extensor surfaces of the upper extremities and trunk may occur.