Which fixative is performed mostly for histochemical study?

Which fixative is performed mostly for histochemical study?

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 are the characteristics of a good fixative?

Characteristics of a good fixative:

  • It must be cheap.
  • It must be stable.
  • It must be safe to handle.
  • It must kill the cell thereby producing minimum distortion of cell constituents.
  • It must inhibit bacterial decomposition and autolysis.
  • It must produce minimum shrinkage of tissue.

What is the principle and properties of fixation?

5.3 PRINCIPLE OF FIXATION Fixation results in denaturation and coagulation of protein in the tissues. The fixatives have a property of forming cross links between proteins, thereby forming a gel, keeping everything in their in vivo relation to each other.

What are the factors affecting fixation?

Factors affecting fixation

  • Temperature: In general, an increase in temperature increased the rate of fixation but also increased the rate of autolysis and diffusion of cellular elements.
  • Size: 1–4 mm thickness.
  • Volume ratio: At least 15-20 times greater than tissue volume.
  • Time: 24 – 48 hours.

How does Carnoy fixative work?

Carnoy’s fixative adds chloroform and acetic acid to the mixture which counteracts the shrinkage effects of ethanol and engenders tissue fixation through hydrogen bonding of the constituents to the tissue [2].

Which is the most commonly used fixative in histopathological specimen?

1. Phosphate buffered formalin. The most widely used formaldehyde-based fixative for routine histopathology. The buffer tends to prevent the formation of formalin pigment.

What is difference between fixation and fixative?

Fixation is considered as physiochemical process where cells or tissues are fixed chemically. 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.

Why is formalin buffered to a neutral pH?

10% neutral buffered formalin is a general histological tissue fixative and standard fixative for use in a diagnostic setting. The phosphates buffered in the formalin will adjust the pH to about 7.0 as the “neutral” infers. The neutral pH inhibit the formation of “formalin pigment”.

How can pH affect fixation?

FACTORS AFFECTING FIXATION The best fixation is usually carried out at a neutral pH (6-8). Lower pH can produce formalin-heme pigment that will appear as black, polarizable deposits in tissue. B. Penetration depends on the diffusion ability of the fixative.

How do you do a histopathological analysis?

Histopathology is the study of the signs of the disease using the microscopic examination of a biopsy or surgical specimen that is processed and fixed onto glass slides. To visualize different components of the tissue under a microscope, the sections are dyed with one or more stains.