- The following fixative is used to prepare tissue for electron microscopy:
(A)B5
( Glutaraldehyde
© Bouin’s fluid
(D) Zenker’s fluid
- A primary lesion caused by mycobacterium bacilli (tuberculosis) developed in the
lung of a previously uninfected individual is referred to as a:
(A) Ghon focus
( Ghon complex
© Simon’s focus
(D) Koch complex
- Ans B
Glutaraldehyde is the classic fiXative for electronmicroscopy. Very small/thin
portions of tissue must be used as its penetrative abilities are poor. B5 and Zenker’s
fluids are mercury-based fixatives that are sometimes used for bone marrow and other
lymphoreticular specimens as they produce excellent nuclear detail. Bouin’s fluid has
traditionally been used for testicular biopsies and small lymph node biopsies, as it
also gives better nuclear detail than neutral buffered formalin. It has the additional
advantage that it colours tiny biopsies yellow and makes them easier to see and more
difficult to lose.
- Ans A
A primary lesion caused by mycobacterium bacilli (tuberculosis) developing in the
lung of a previously uninfected individual is called a Ghon focus. If it also involves
infection of surrounding lymph nodes, it is known as a Ghon complex. A Ghon’s
focus results from haematogenous seeding at the time of initial infection, is present at
the apex of the lung, contains viable organisms and serves as the source of
reactivation in approximately 10% of people.