1. Specialties Hospital, Medical Research Unit in Biochemistry, Instituto Mexicano del Seguro Social (Mexican Institute of Social Security), Mexico; PO Box 103-265, Col. Alianza Popular R, Coyoacan, 04801, México, D.F., México
2. Specialties Hospital, Medical Research Unit in Biochemistry, Instituto Mexicano del Seguro Social (Mexican Institute of Social Security), Mexico
3. Hospital Juarez (Juarez Mexico City Hospital), Mexico