L.A. Gear Inc., Los Angeles, said it plans to introduce a jeans division during the second quarter . . . American Medical International said it has put a minority interest in its United Kingdom operations up for sale through a public offering . . . American Savings & Loan will join Los Angeles-based First Interstate Bank of California's Cirrus automated teller machine network . . . The London-based investment arm of the Kuwaiti government announced that it has further increased its stake in British Petroleum Co. to 19.27% from 19.24% . . . The board of Warner Communications Inc. declared a 40% increase in the company's dividend, to 56 cents from 40 cents.