This article introduces the precautions and provides solutions to the common problems faced by clients before, during and after cryosectioning.
Speaking of organic diseases, no matter how advanced clinical screening technology is under most circumstances, a pathological test is still the most authoritative and reliable way to confirm the diagnosis. Pathological diagnosis delivers 5 clinical values- confirmation of diagnosis, grounds for clinical therapy, an indicator of the stages and development of the medical condition, and provision of valuable information and experience to disease development, therapy and scientific research.
Frequently Asked Questions and Solutions To Cryostat Machine Troubleshooting
Production of high-quality sections requires a long period of training and experience with cryostat application. The following table summarizes the common problems and provides reasons behind them and their solutions during cryosectioning.
Frosting in the chamber.
The window is left open for too long whereas too much gas being exhaled into the chamber.
Close the window and wear a mask during sectioning.
Section becomes sticky.
Overheating of the tissue, blade and the anti-roll plate causes the section to melt.
Set it to a lower temperature. Resume the sectioning when the chamber and other appliances drop to the adjusted temperature.
Unable to spread out the section due to cracking.
Low temperature of the tissue; Electrostatic interactions Oversized surface area of the tissue; wrong anti-roll plate position and wrong angle of the tool holder; unclean blade or unwashed anti-roll plate; broken blade.
Adjust the temperature. Trim the surface of the tissue. Increase the thickness of the section. Adjust the position of the anti-roll plate. Set the angle of the tool holder to 4°~6°. Change the blade or adjust the position of the blade. Use a dry brush to clean the blade and anti-roll plate.
Anti-roll plate curls up.
Unsuitable distance between the blade and the anti-rolled plate.
Adjust the anti-roll plate to prevent it from moving forwards.
Specimen clashes with the anti-roll plate.
Unsuitable distance between the blade and the anti-roll plate.
Adjust the anti-roll plate to pull it backwards.
Scratches on the section.
The blade and the anti-roll plate are chipped.
Change the blade and the anti-roll blade. Use a new blade or get a new anti-roll plate.
Vibrations and audible noise.
Tissue and specimen head are not fully frosted. The specimen head and blade are not fixated properly. Tissue is too hard with uneven surface.
Frost the tissue and specimen head again. Check the screw bolt of the specimen head, blade, and specimen clamp. Increase the thickness of the section.
Uneven thickness of the section.
Temperature setting and angle of the blade may not be suitable for sectioning. There may be frosting on the other side of the blade. Speed of rotating the handle bar may not be consistent or unsuitable for sectioning. The blade is not safely locked in one place. The specimen head is fixed in the wrong way. Angle of the tool holder angle is not accurate.
Choose the right setting for temperature. Adjust the angle of the blade. Defrost the blade. Adjust the speed of sectioning. Check the screw bolts of the blade and specimen head. Set the correct angle for the specimen holder.
Tissue stuck on the anti-roll plate.
Temperature of the anti-roll plate is too high. Tissues are stuck on the edge of the plate.
Resume sectioning once the anti-roll plate cools down. Use ethanol to remove the fats and rust on the blade.
Back of the anti-roll plate curls up after being lifted up.
The temperature of the anti-roll plate is too high. The section is not embedded properly in the OCT compound.
Resume sectioning once the anti-roll plate cools down. Thickness of the embedding should be consistent. It also should be regular in shape. Use a brush to spread out the section.
The slice cannot stick on the glass slide.
Temperature of the glass slide is too low.
Resume sectioning once the glass slide heats up.
Sectioning is not smooth. The blade gets stuck.
Cryochamber is not fully dry.
Switch off the machine and restart it after the chamber becomes fully dry.
Cryostat Machine Precautions and Guidelines
In order to facilitate the procedures of pathological diagnosis, operators have to understand the dos and don’ts when using a cryostat machine in practice. The following sections will mention the precautions before, during and after cryosectioning. Let’s check it out now!
Please be aware that cracking of tissue will occur if the tissue is frosted for too long.
Lock the blade cover and specimen head. Then, keep the blade mounted and locked before cryosectioning.
Before frosting the sample, it should be embedded in the OCT compound and the specimen should be placed beneath the bottom of the OCT box. The section should be well integrated into the OCT compound. If the OCT process is done properly, it can save a lot of time for trimming the tissue and increase the durability of the blade.
After ensuring that the machine can work properly, the specimen in the cryochamber will be quickly cooled down to a lower temperature. Use a tong to take out the specimen discs for further cooling. RWD’s specimen head has a handle bar to prevent one’s hands from getting frostbite.
Before cryosectioning, use the joystick and feed key to adjust the angle of the sample, and manoeuvre the distance between the sample and the blade. This can prevent the tong from clashing with the blade cover or damaging the tissue.
For some tissues, it is relatively difficult to get the samplings. For instance, the adipose tissues require a lower temperature for cryosectioning. The optimal temperature range would be -35℃ to -50℃ that can greatly increase the thickness of the section.
Pay attention to the speed of sectioning. It shouldn’t be too fast. Generally speaking, as the sample gets harder, the speed of sectioning will reduce accordingly. Compared to the counterparts with half-opened windows, RWD cryostat machine boasts its refrigerant system and accurate temperature control that maintain the quality of the section while leaving the window open for a long time. As such, the overall operation is highly optimized.