Obesity Surgery May Cure Diabetes By LINDSEY TANNER    CHICAGO (AP) -- Patients who undergo obesity surgery get far more than cosmetic benefits - many also shed fat-related ailments including diabetes, high blood pressure and high cholesterol, researchers say.    Their report - an analysis of 136 studies - suggests that in some cases, the drastic operations may alter the patient's body chemistry itself and relieve conditions that can lead to heart attacks, strokes and kidney failure...