One of the nation’s largest HMOs is laying off 530 employees in Southern California.  Kaiser Permanente said the layoffs — constituting about eight-tenths of one percent of its employees — would be spread across its 65,700 employees and doctors working in offices and hospitals from Kern County to the Mexican border. Many may also be rehired next year, when Kaiser Permanente expects “significant membership growth,” a statement issued by the company read according to a recent report in the Palm Desert Patch.