RESUMEN
Normal phase high performance liquid chromatography has been optimized for both evaporative light scattering detection and tandem mass spectrometry in order to characterize the natural phospholipids (PL) (classes and molecular species) of raw and cooked pork meat. The PL fraction included phosphatidylcholine (PC) (42.9%±4.5 for raw vs 42.6%±8.0 for cooked meat), plasmalogen-phosphatidylethanolamine (pPE) and phosphatidylethanolamine (PE) (26.7%±3.1 vs 28.5%±2.3), cardiolipin (CL) (8.3%±2.9 vs 6.3%±0.7), sphingomyelin (Sph) (7.5%±0.9 vs 8.3%±2.1), phosphatidylinositol (PI) (6.8%±0.7 vs 6.5%±2.1) phosphatidylserine (PS) (4.9%±0.5 vs 4.6%±1.4) and lysophosphatidylcholine (LPC) (2.9%±1.3 vs 3.3%±2.6). Arachidonic acid (absent in Sph) was mainly present in pPE and PI and formed molecular species with a saturated fatty acid, such as stearic (as in PI, PS, PE and PC) or palmitic acid (as in PE and PC), or the respective vinyl ethers in pPE (p18:0 and p16:0); however, in PC, arachidonic acid also formed combinations with oleic and linoleic acid. Palmitic acid formed the most abundant molecular species in PC, but not in CL, PE, PI and PS. Unexpectedly, the cooked pork meat showed an increased content of the molecular species of PI and LPC with more unsaturated fatty acids (18:0/20:4 and 18:2, respectively) with respect to raw meat.
RESUMEN
A multiple spin-echo (MSE) sequence has been applied for the first time to study trabecular bone ex vivo. The second echo generated by the demagnetizing field presents discrete drops in signal intensity for certain values of the pitch of the magnetization helix created by the correlation gradient. These dips may reflect characteristic pore sizes in the trabecular bone specimens. This hypothesis is supported by similar experiments performed on a phantom with uniform pore size distribution. Trabecular bone images weighted in the MSE contrast mechanism are reported.