What is the composition of Bouin's fixative?
It is prepared by a mixing saturated solution of picric acid in 95% ethanol (80ml) with formalin (37-40% formaldehyde) (15 ml) and glacial acetic acid (5ml). Gendre's fixative contains more picric acid than Bouin's, because of greater solubility (6.23%w/v) in ethanol than in water (1.23%w/v).
What is Bouin solution in histology?
Bouin solution, or Bouin's solution, is a compound fixative used in histology. It was invented by French biologist Pol Bouin and is composed of picric acid, acetic acid and formaldehyde in an aqueous solution.
What is Bouin's fluid made of?
It was invented by French biologist Pol Bouin and is composed of picric acid, acetic acid and formaldehyde in an aqueous solution. Bouin's fluid is especially useful for fixation of gastrointestinal tract biopsies because this fixative allows crisper and better nuclear staining than 10% neutral-buffered formalin.
What is an example of fixative mixtures?
Fixative mixtures allow very quick tissue fixation; examples are Bouin solution (picric acid, formaldehyde, and glacial acetic acid) and Carnoy (ethanol, chloroform, and glacial acetic acid). Their use is limited to special cases (e.g., fixation in Bouin solution for bone marrow biopsies).
What is Bouin's fixative?
How long does Bouin's solution fix?
Is Bouin's solution explosive?
Is picric acid explosive?
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How is Bouins fixative prepared?
To prepare 1 L of Bouin's fixative, dissolve 2 g of picric acid in 500 mL of H2O. Filter through a Whatman No. 1, or equivalent. Add 20 g of paraformaldehyde, and heat to 60°C in a fume hood.
What are the three types of fixatives?
There are five major groups of fixatives, classified according to mechanism of action:Aldehydes.Mercurials.Alcohols.Oxidizing agents.Picrates.
What is fixative testicular biopsy?
Bouin solutionDue to concern that common fixatives, such as formalin, may distort the architecture of testicular tissues, Bouin solution has traditionally been the recommended fixative for testis biopsy specimens. Bouin solution is a preparation of 5% acetic acid, 9% formaldehyde, and 1.5% picric acid in aqueous solution.
What happens when Bouins solution dries out?
Bouin's Solution is a yellow liquid made up of formaldehyde, picric acid, and acetic acid. It is classified as a category 1A carcinogen due to the presence of Formaldehyde. If the solution dries out, the picric acid can become explosive.
What are the two types of fixation?
The two main mechanisms of chemical fixation are cross-linking and coagulation. Cross-linking involves covalent bond formation both within proteins and between them, which causes tissue to stiffen and therefore resist degradation.
What is the most common fixative?
FormaldehydeFormaldehyde is commonly used as 4% solution, giving 10% formalin for tissue fixation. 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.
What is fixation of a testicle?
Fixation is, in fact, a procedure in which a “pocket” is created in the scrotal tissue, the testicle is positioned in it and is sutured to the scrotum. This ensures that it will not be able to move from its place, enabling normal development.
Why biopsies of testicular masses are never done?
Surgery to diagnose testicular cancer Most types of cancer are diagnosed by removing a small piece of the tumor and looking at it under a microscope for cancer cells. This is known as a biopsy. But a biopsy is rarely done for a testicular tumor because it might risk spreading the cancer.
How do you Detors a testicle?
(B) After appropriate sedation and analgesia has been administered, manual detorsion is performed by grasping the testicle and rotating it within the scrotum outward (medial to lateral) one to two full 360 degree turns.
What does Bouins do?
The main use of Bouin's fluid is the fixation of lymph nodes, prostate and kidneys biopsies. It is a very good fixative when soft and delicate tissue structures must be preserved on the other hand it is not advisable to use it to fix the tissues for electron microscopy.
Which fixative is poisonous?
Mercury-based fixatives are toxic and all should be handled with care. They should not be allowed to come into contact with metal, and should be dissolved in distilled water to prevent the precipitation of mercury salts.
Which fixative is explosive?
Picric acid is explosive when dry.
How many types of fixative are there?
Depending on your specimen, you can choose one of the three general types of fixation processes – heat fixation, perfusion fixation, and immersion fixation.
What are the classification of fixatives?
Fixatives are also classified as additive and non-additive. Additive fixatives combine with molecules of the tissue so that the fixative, or some of its components, become part of the tissue, and it is present in the following steps of the histological processing.
What types of fixation are there?
Freud identified three types of fixations: Oral. Anal. Phallic.
What are fixatives give example?
Fixation is considered as physiochemical process where cells or tissues are fixed chem- ically. Fixatives perform various functions such as prevention of autolysis and tissue putrefaction. Various fixative agents include formaldehyde, glutaraldehyde, osmium tetroxide, glyoxal, picric acid, and so on.
Bouin’s fixative - CSH Protocols
Bouin’s fixative. 2 g picric acid powder or saturated aqueous picric acid (see below) . 20 g paraformaldehyde Formalin (40% w/v formaldehyde), as an alternative to paraformaldehyde (see below)
Fixing Samples for IHC: Tips and Tricks: Novus Biologicals
Read tips for fixation, including choosing a fixative (formalin vs. alcohol), fixation methods, overfixation versus underfixation, and how fixation affects IHC staining.
Is Bouin's solution necessary for Masson's Trichrome staining?
I believe the Bouin's is an important step in the MT stain, for making the tissue stain better with acid dyes. It doesn't matter that the tissue has already been fixed.
Bouin’s fluid fixation — The Open Lab Book v1.0 - Read the Docs
Bouin’s fluid fixation¶. Contributed by Martin Fitzpatrick, University of Birmingham, United Kingdom. Fixation of histological samples with Bouin’s fluid. Prepare 75ml saturated aqueous solution of picric acid
BOUIN'S FIXATIVE PURPOSE: REAGENTS: CAUTION: CARCINOGENIC ... - WebPath
BOUIN’S FIXATIVE Saturated picric acid 1500.0 ml Formaldehyde 500.0 ml Glacial acetic acid 100.0 ml Mix well, stable for 1 year. Label, inital and date.
MATERIAL SAFETY DATA SHEET (MSDS) - Loba Chemie
BOUIN`S FLUID Safety Data Sheet www.lobachemie.com 10/12/2018 2/11 2.2. Label elements Labelling according to Directive 67/548/EEC or 1999/45/EC Hazard symbols :
What is the effect of formalin on tissue?
The tissue hardening effect of formalin is balanced by the soft tissue fixation of picric and acetic acids. The tissue swelling effect of acetic acid is balanced by the tissue shrinking effect of picric acid.
What is Gendre's fixative?
Gendre solution is an alcoholic version of Bouin solution. An alcoholic solution saturated with picric acid is used instead of an aqueous solution saturated with picric acid when making this solution. This solution is useful when glycogen and other carbohydrates must be preserved in tissue. It is prepared by a mixing saturated solution of picric acid in 95% ethanol (80ml) with formalin (37-40% formaldehyde) (15 ml) and glacial acetic acid (5ml). Gendre's fixative contains more picric acid than Bouin's, because of greater solubility (6.23%w/v) in ethanol than in water (1.23%w/v).
What is the function of acetic acid in bouin solution?
The ace tic acid in this fixative lyses red blood cells and dissolves small iron and calcium deposits in tissue. A variant in which the acetic acid is replaced with formic acid can be used for both fixation of tissue and decalcification. The effects of the three chemicals in Bouin solution balance each other. Formalin causes cytoplasm ...
What is Bouin solution?
Jump to navigation Jump to search. Bouin solution, or Bouin's solution, is a compound fixative used in histology. It was invented by French biologist Pol Bouin and is composed of picric acid, acetic acid and formaldehyde in an aqueous solution.
Can you store bouin solution in alcohol?
Wet tissue fixed in Bouin solution should be stored in an alcohol and water solution rather than Bouin solution. Since Bouin solution contains formaldehyde, picric acid and acetic acid, appropriate safety precautions for these substances should be taken and regulations followed.
Does Bouin's solution have formalin?
Only the picric acid component of Bouin's solution is needed to bring about this correction of trichrome staining. When using Bouin solution, several potential problems can arise. Due to the formalin in the solution, formalin pigment may be present when viewing tissue sections under the microscope.
Is picric acid explosive?
In particular, noting that picric acid can be explosive, sensitive to friction and shock when dry and in contact with some metals can form unstable metal picrates. Under the name "Bouin's fluid" this fixative is also widely used for marine invertebrates. It is prepared as follows: picric acid, saturated aqueous solution – 75 ml; formalin, ...
What is the purpose of histology fixatives?
We are all using some kind of histology fixatives in the lab, but do we actually know what it’s doing to our cells and tissues? No matter what histology fixative we use, the purpose is to immobilize antigens and retain good cellular structure to allow us to do some kind of histology analysis.
What is PFA in biology?
What exactly is PFA? PFA (or paraformaldehyde) is the condensation product of formaldehyde which is a water-soluble, colorless and toxic gas . Formaldehyde acts as a fixative because it reacts with the primary amines on proteins to form cross-links known as ‘methylene bridges’.
Why are antigenic sites masked?
Due to the formation of the protein cross-links during fixation, antigenic sites can be masked which can prevent recognition of the antigen by the antibody. This can be overcome by adding in an antigen retrieval step before immunohistochemistry protocols. This can be via a heat- or chemical-induced method.
What are some fixatives for histology?
Histology fixatives are not in any way restricted to these two solutions. There are many other fixatives we use every day such as methanol, acetone, glutaraldehyde, and many more. The choice depends on the starting cells or tissue and also the technique to be applied.
How long does it take for PFA to fix?
PFA adds to the side-chains of basic amino acids and to the amide nitrogen atoms of peptide linkages which stabilizes proteins and preserves morphology. Although it is a rapidly penetrating fixative, it cross-links proteins very slowly and often takes up to a week to achieve a good level of fixation. Consequently, one of the most common problems with PFA is under-fixation. Small pieces of tissue should ideally be immersed in PFA for at least 24h for a good level of preservation. Larger tissues, such as human biopsy samples, may need up to a few weeks in PFA to achieve adequate fixation.
Why do we fixate?
Usually we do fixation in order to do immunohistochemistry to allow us to investigate our tissue samples using antibodies. The whole process of fixation can be problematic as different epitopes require different fixation techniques and so this is yet another method that requires optimization.
What is the function of formaldehyde?
The function of formaldehyde, which cross-links proteins, is discussed above. The role of the picric acid in this solution is to slowly penetrate into the tissue and cause coagulation of proteins by forming salts with basic proteins. This can, however, cause some shrinkage of the tissue.
What is the color of the hematoxylin stain?
For histological analyses, tissues are sliced into thin (5–10 μm) sections with either a microtome or a cryostat and stained to distinguish between different tissue components either with hematoxylin and eosin (H&E) staining or with immunohistochemistry. Hematoxylin, a basic dye, stains acidic structures purple or blue (e.g., nuclear deoxyribonucleic acid (DNA), ribosomal RNA, and rough endoplasmic reticulum). Eosin, an acidic dye, stains basic structures pink (e.g., cytoplasmic components) ( Fischer, Jacobson, Rose, & Zeller, 2008 ). Both paraffin-embedded tissues and fresh-frozen tissues can be used for H&E staining ( Fig. 3 A) or immunohistochemistry ( Fig. 3 B). Keratin antibodies used for immunofluorescence staining in our laboratory are summarized in Table 1.
What is Fig. 50.3?
Fig. 50.3. Photomicrographs of bACL histologic sections stained using Masson's trichrome methods . (A) A bACL cultured under static conditions, ( B) a bACL submitted to cyclic traction, and (C) native human ACL (×40). Note the wavy pattern of highly organized bundles of collagen fibers induced by cyclic traction.
What is the best fixative for tissue fixation?
It is always best to work with the pathologist who will be evaluating the tissues before proceeding. Neutral buffered formalin solution is the most universal fixative used. Tissues are often left in formalin for long periods. Due to cross linking of amino groups by the aldehydes, many epitopes are modified making immunohistochemistry difficult or impossible. Fekete's acid alcohol formalin minimizes this problem, especially when tissues are transferred to 70% ethanol after overnight fixation. Commercially available zinc based preservatives are being promoted to maintain epitopes, optimize immunohistochemical results while maintaining some degree of the histologic quality that pathologists are used to with paraffin sections. Bouin's solution is popular as a general fixative but it hyalinizes collagen fibers so fine detail of the skin can be difficult to interpret. Use of Bouin's solution requires washing in tap water and transfer to ethanol. Failure to do so results in major artifacts often making the tissue unusable. These and other fixatives are discussed in Chapter 30 on Necropsy Methods which includes formulations for their preparation.
What is the color of the cytoplasm in rabbits?
Trichrome staining of oral gingiva of rabbits. Rabbits’ gingival tissues were extracted and processed using Masson's Trichrome. Collagen stains blue and the nuclei are stained dark brown. The muscle tissue is stained red and cytoplasm is stained pink. This example was prepared as detailed in the text. Scale bar is 600 μm.
How long does it take to stain with Weigert's iron hematolin?
Stain with Weigert's Iron Hematoxylin (equal parts of Hematoxylin A and Hematoxylin B) for 5–10 min at room temperature. Stain for 5 min if solution is fresh. Stain for 10 min if solution is a few days old. Weigert's Iron Hematoxylin is stable for up to 2 weeks at 4°C. Separated solutions are stable for up to 5 years.
What is the best chemical for fixation of water samples?
Common fixatives used in microbiology such as formaldehyde, glutaraldehyde and Lugol's solution are not suited for the fixation of many species, and lead to specific artifacts ( Pfister et al., 1999 ). Bouin's solution, which contains picric acid, formaldehyde and acetic acid, proved as best chemical for routine methods ( Montagnes and Lynn, 1987 ).
How to harden a sample?
Place the sample in the mold in the correct orientation. Fill the rest of the mold with molten paraffin to cover the sample and allow it to harden.
What is Bouin's fixative?
Bouin's Fixative. Bouin's solution is a popular fixative for embryonic studies and skin, due to its excellent preservation of nuclei and chromosomes. Bouin's is very compatible with the trichrome stain due to its mordanting effect on the tissue.
How long does Bouin's solution fix?
Fixation: Tissues fixed in Bouin's solution should be changed to 70% ethanol after 4-48 hours of fixation (less than 24 hours is optimal). If the tissues are fixed longer than this they tend to become brittle and difficult to section. (NOTE: long term storage in 70% ethanol can lead to shrinkage of the tissue)
Is Bouin's solution explosive?
Hazards: Bouin's solution contains formaldehyde ( more on formaldehyde). Bouin's solution also contains Picric acid (which gives the solution its yellow color). Picric acid is highly explosive when dry. If your lab has a stock bottle of Picric Acid that does not have a layer of liquid in it, CALL YOUR SAFETY/RISK MANAGEMENT PEOPLE IMMEDIATELY FOR DISPOSAL, DO NOT ATTEMPT TO HANDLE THE BOTTLE YOURSELF. For MSDS information on Picric Acid, you can locate an appropriate MSDS at the Vermont SIRI MSDS Archive.
Is picric acid explosive?
Picric acid is highly explosive when dry. If your lab has a stock bottle of Picric Acid that does not have a layer of liquid in it, CALL YOUR SAFETY/RISK MANAGEMENT PEOPLE IMMEDIATELY FOR DISPOSAL, DO NOT ATTEMPT TO HANDLE THE BOTTLE YOURSELF.
