Amylase is a digestive enzyme made primarily by the pancreas and salivary glands. Enzymes are substances made and used by the body to trigger specific chemical reactions.
Luxating patella - a knee cap problem in dogs. The patella, commonly referred to as the knee cap is usually located in the centre of the knee joint. A luxating patella is a knee cap that moves out of its normal location, as indicated by the term luxating which means out of place or dislocated.
Dogs with luxating patellae can have the symptoms you are seeing in Casey. This is a condition in which the kneecaps do not stay in the groove they should travel in. They pop out, usually to the inside of the leg, producing pain, apparent weakness, difficulty jumping (common) and difficulty moving (less common).