Author Question: Describe the steps involved in cytogenetic harvesting and banding, and explain the purpose of each. ... (Read 30 times)

Pineapplelove6 · **on:** Jun 25, 2018

Describe the steps involved in cytogenetic harvesting and banding, and explain the purpose of each.

What will be an ideal response?

Question 2

A patient is receiving treatment for Hodgkin lymphoma. Six weeks after cessation of the treatment, a cytogenetic analysis is performed. A structural aberration is found. Name the most probable aberration(s), and explain how these may occur.

What will be an ideal response?

IAPPLET · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

Answer:
Step 1: Arrest mitotically active cells in metaphase by incubating the sample with colchicine or colcemid that disrupts the spindle apparatus
Step 2: Incubate the mixture in a hypotonic solution (0.075M KCl) to lyse the erythrocytes and swell the nucleated cells
Step 3: Fix cells with Carnoy's fixative (3:1 mixture of methanol to glacial acetic acid)
Step 4: Make a trial slide by adding 3-4 drops of the final cell suspension mixture onto a clean glass slide
Step 5: Dry the trial slide and examine it by phase microscopy. If the first slide does not show optimal quality, the suspension can be concentrated or diluted to improve the slide's quality.
Step 6: Aging of the slide: Heat the slide in a 60 C oven overnight to prepare for banding.
Step 7: Banding: stain chromosomes; Q-banding is done with quinacrine; G-banding is done with Giemsa stain

Answer to Question 2

Answer: The most probable chromosomal aberrations are deletions of chromosomes 5 and 7. Also, 11q23 and 21q22 aberrations could be found in patients treated with chemotherapy. Aberrations in chromosomes 5 and 7 are related to treatment with alkylating agents. Aberrations in 11q23 and 21q22 are related to treatment with topoisomerase-II inhibitors.