What are the mercuric chloride fixatives?
What are the mercuric chloride fixatives?
Mercuric-chloride-based fixatives include B-5 and Zenker’s. These penetrate tissue relatively poorly and require thin sections for adequate fixation (2 mm). Mercuric chloride fixatives provide excellent nuclear detail and in the past were commonly used for fixation of hematopoietic and reticuloendothelial tissues.
Is mercuric chloride a coagulant fixative?
Mercuric chloride It is a powerful protein coagulant which leaves tissue in a state which produces strong staining with acid dyes. It reacts with phosphate residues of nucleic acids and effectively fixes nucleoproteins.
What are the different types of fixatives?
Popular fixative solutions
- Phosphate buffered formalin.
- Formal calcium.
- Formal saline.
- Zinc formalin (unbuffered)
- Zenker’s fixative.
- Helly’s fixative.
- B-5 fixative.
- Bouin’s solution.
Which chemical is used as Helly’s fixative?
If the glacial acetic acid is replaced by 5 ml of formalin (37–40% formaldehyde), the resulting solution is Helly’s fixative, also sometimes called “formol-Zenker”.
What is fixative example?
The most common precipitating fixatives are ethanol and methanol. They are commonly used to fix frozen sections and smears. Acetone is also used and has been shown to produce better histological preservation than frozen sections when employed in the Acetone Methylbenzoate Xylene (AMEX) technique.
Which fixative is used for electron microscopy?
Osmium tetroxide is the most common secondary fixative and it has the advantage of preserving lipid membranes, which are not preserved with aldehyde fixation alone. It also acts as a stain and provides a significant amount of contrast and conductivity to the sample.
What is the most common fixative used in histology?
formaldehyde
The most commonly used fixative in histology is formaldehyde. It is usually used as a 10% neutral buffered formalin (NBF), that is approx. 3.7%–4.0% formaldehyde in phosphate buffer, pH 7.
What is simple fixative?
Simple Fixatives – These fixatives are made up of simple chemical compounds and take more time for the fixation of tissues. For example, Formalin, Picric acid, Mercuric oxide, osmic acid, Osmium tetroxide etc.
What is fixative agent?
A fixative is a stabilizing or preservative agent: Dye fixatives or mordants, are chemical substances used in processing fabrics to create circumstances in the micro-substrates causing dye molecules to adhere and remain that way.
What are the primary and secondary fixatives used in electron microscopy?
There are several chemicals that are widely used for the initial or primary fixation, including glutaraldehyde, formaldehyde, and acrolein. Glutaraldehyde and acrolein cause extensive, rapid and permanent cross-linking of proteins.
How do you preserve tissues for an electron microscope?
Small pieces of tissue specimens are optimally placed rapidly into glutaraldehyde and fixed for at least 1 h at room temperature (23 °C) and then post-fixed in osmium tetroxide. Fixed cells are embedded in agar and processed based on the tissue type.
Why do we use 10% formalin for fixation?
Information about 10% Formalin The fixative 10% buffered formalin is commonly used to preserve tissues for routine histology in many labs. The formaldehyde has a greater chance for oxidation in this concentration of tissue fixative and eventually the solution will start to drop in pH, in spite of the buffer.
What is an ideal fixative?
An ideal fixative should: Preserve the tissue and cells as life-like as possible, without any shrinking or swelling and without distorting or dissolving cellular constituents. Prevent putrefaction by bacteria and prevent autolysis by cathepsin-containing cells.
What is the most common fixative?
Formalin
Formalin is most commonly used fixative. It is cheap, penetrates rapidly and does not over- harden the tissues. The primary action of formalin is to form additive compounds with proteins without precipitation. Formalin brings about fixation by converting the free amine groups to methylene derivatives.
What is formalin fixative?
Formalin is the fixative used most often for newly-obtained specimens as well as in archived paraffin blocks. Ever wonder how it works? Mechanism of Formalin Fixation. Formalin (a solution of formaldehyde in water) preserves proteins and cellular organelles in a stepwise process.
What is another name for fixative?
What is another word for fixative?
| adhesive | glue |
|---|---|
| gum | paste |
| cement | bonder |
| stickum | mucilage |
| superglue | epoxy resin |
What is composition of fixative?
The most commonly used fixative in histology is formaldehyde. It is usually used as a 10% neutral buffered formalin (NBF), that is approx. 3.7%–4.0% formaldehyde in phosphate buffer, pH 7.
Which fixative is best for electron microscopy?
Fixation of tissue: Perfusion fixation is preferred. For this we recommend using 2% formaldehyde and 2.5 % glutaraldehyde in 0.1 M Sodium Cacodylate buffer, pH 7.4.
What is a mercury chloride fixative used for?
Mercuric chloride fixatives provide excellent nuclear detail and in the past were commonly used for fixation of hematopoietic and reticuloendothelial tissues. Due to the inherent toxicity of mercury, these fixatives have been discontinued in most laboratories.
What are the disadvantages of mercuric chloride fixation?
A further major disadvantage of mercuric chloride fixation is the inevitable formation of deposits of intensely black precipitates of mercuric pigment in the tissues. This subsequently gives them inferior value for immunohistochemical and molecular studies.
What is the precipitate in tissues fixed with mercuric chloride?
Tissues fixed with solutions containing mercuric chloride usually contain a dark brown to black precipitate referred to as mercury pigment. This has to be removed from the tissues.
Is mercuric chloride poisoning re-emerging?
Only sparse data, reporting the clinical symptoms, the anatomo-pathological findings, the analytical procedures or the treatment have been published and no exhaustive analys … Among mercury-related intoxications, the re-emerging of mercuric chloride poisoning has been recently described in literature.