Penn-Century MSA-250-M for Mouse - Manual (Page 9)

9
Attach dose volume spacers as desired to the plunger rod. Press tightly together against plunger handle. Remove
one by one for precise individual aerosol doses.
Attaching and using the dose volume spacers (“stops”)
§ After filling the FMJ-250 syringe to capacity, pull the plunger upward until there is enough
space to attach the appropriate spacers to the plunger rod. Note: If you pull too far, the
plunger will come all the way out. This can cause air to enter the syringe.
§ The volume spacers will snap onto the plunger
rod with a clicking sound.
§ When all spacers are attached, push down on
the plunger firmly until the all the volume spacers
are pushed together against the top of the
syringe, with no gaps. Some test formula may be
ejected as you do this. The system is now ready.
§ To administer Dose #1, carefully remove the
spacer or spacers closest to the thumb button of
the plunger that equal the dose volume desired.
BE CAREFUL NOT TO CHANGE THE POSITION OF
THE PLUNGER. The gap or space that
remains after the spacer is removed equals the volume of the dose.
§ Push the plunger with quick, sharp, firm and fast motion to produce a uniform puff of aerosol
spray. If the motion is too slow, you will produce only a stream.
§ Then, remove the next spacer and repeat.
§ In this way, a series of doses (for example, five 50 µl doses) can be delivered sequentially, one
after the other, from one animal to the next, before the syringe needs to be refilled.
§ Practice with water. It is best to practice use of the volume spacers with water to get a sense
of the thumb pressure that is required. Pressure should be quick and firm – not tentative,
gradual or slow - to create a full plume of aerosol, especially at small volumes.
§ Be mindful of air bubbles in the syringe.
Particularly at small doses, any air bubbles
trapped in the syringe when it was filled will
impair performance. When you practice using
the device, if you observe small, hair-like
streaks in the aerosol, or you have difficulty
administering smaller doses without streaming,
this may indicate that there are air bubbles that
are trapped in the syringe that must be forced
out or “purged.”