Lysophospholipids - chemistry, Pyridines - chemistry, Lung - chemistry, Chloroform - chemistry, Rats, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods, Lysophospholipids - blood, Sphingosine - analogs & derivatives, Animals, Lysophospholipids - analysis, Cattle, Sensitivity and Specificity, Brain Chemistry, Chemical Fractionation - m...