An increasing number of laboratories are performing flow cytometric analyses of solid tissues and tumours for antigen expression, ploidy, and proliferative index. The quality of the final result in the flow cytometric analysis of any tissue depends upon the quality of the prepared suspension. Various manual methods for dissociating tissue have been used alone or in combination and include:

• Chemical treatment
• Manual disaggregation
• Enzymatic digestion
• Enucleation techniques

These methods can be time consuming, and all have limitations with regard to operator safety and the quality of the final cell suspension. Tissue composition must be considered, since some tissues disaggregate more readily than others, and abnormal tissue might contain very delicate cells. Thus, differences in technicians’ skills and technique can result in low cell viability and yield, as well as poor reproducibility.

Medimachine Workflow:
Flexibility for different tissue types

The following is an overview of the steps for using the Medimachine system for typical tissue disaggregation. The procedure should be adapted for your laboratory and each tissue type you receive. A small piece of tissue (up to 10 mm3), free of fat and necrosis, is inserted into the Medicons together with ~1.0 mL of the desired suspension buffer (for example, PBS).

The Medicons is then inserted into the Medimachine and the machine is started. The machine can be run from 10 seconds to 4 minutes depending upon the tissue type and the cell suspension you want.

As the tissue is disaggregated, the cells pass through the screen into the suspension liquid in the bottom of the Medicon (Figures 1 and 2).

Once the tissue is disaggregated, the Medicons is removed from the Medimachine. A needless syringe is then inserted in the syringe port to recover the cell suspension. The Medicons may be rinsed with suspension buffer to ensure maximum cell recovery (Figure 3). Select the appropriate Filcons pore size for isolation of the desired cells (Figure 4).

The Medimax system consists of three components:

• Medimax
• Medicons
• Filcons & Filcons Max

The compact Medimax unit is the heart of the system. It works with all types of Medicons and operates at a constant speed of approximately 80 rpm.

A small piece of tissue (up to 10 mm3), free of fat and necrosis, is inserted into the Medicons together with the correct amount of liquid (~1.0 mL for codes 79300 and 79400; ~16.0 mL for code 79500) of the desired suspension buffer (for example, PBS)

The Medicons is then inserted into the Medimax and the machine is started. The machine can be run from 10 seconds to 4 minutes depending upon the tissue type and the cell suspension you want. As the tissue is disaggregated, the cells pass through the screen into the suspension liquid in the bottom of the Medicons. Once the tissue is dissociated, the Medicons is removed from the Medimax. A needleless syringe is then inserted in the syringe port to recover the cell suspension. The Medicons may be rinsed with suspension buffer to ensure maximum cell recovery. Select the appropriate Filcons (or Filcons-Max if a 50 mL tube is used) pore size for isolation of the desired cells.