Looking in an unbiased way, PM most likely means "post meridiem", and ul most likely means "Underwriters Laboratories". That does not make any sense.
Considering captalization, PM could mean "Prime Minister". The meaning of ul (lower case) is questionable, probably it is the abbreviation for "unlucky". Still not very sensible.
Assuming that Aalaa is looking for meanings related to measurement units in "animal health". Then, M may stand for "molar" = moles per litre. P remains unclear. As a prefix of a measurement it means "peta" (=1E15). I doubt this because water is 55.5 M, and a 1 PM solution would thus have 1 solvent molecule (water) per 1.8E13 solute molecules (clearly far above any reasonable saturation limit; this is more or less similar for any other solvent of your choice). Ignoring the capitalization, p can in fact mean pico, as mentined before. But then this is a bad pitfall! Be careful with capitalization for measurement prefixes, they do have a particular meaning, and d≠D, m≠M, f≠F, p≠P and so on!
Now, "ul" could be upper lobe. But if it should imply a measurement unit, l is most likely litre. The prefix u is sometimes used instead of µ and can mean "micro" (=1E-6).
After nitpicking all these (to my opinion important) "minor" issues of interpretation, I agree with Joachim that you might finally want to convert a volume to a molar concentration - and this is only sensible in a very specific context, and for this additional information is missing.
What can we learn?
Specify your question, write what you mean clearly and unambigiously. Provide a context. Use standard (SI) units and abbreviations.
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