Tylan Corp. issued a letter to its...

Tylan Corp. issued a letter to its shareholders asking them to defer making a decision on a cash tender offer at $5 a share by a subsidiary of Autoclave Engineers Inc. for the outstanding shares of common stock of the Torrance company . . . Jury selection began at federal court in New York for the securities fraud trial of Singer Co. chairman and takeover specialist Paul Bilzerian . . . Hitachi Ltd. and Electronics Data Systems Corp. said they have formed a joint venture company that will operate National Advanced Systems Inc., which they bought from National Semiconductor Corp. for $398 million . . . Nu-Med Inc. in Encino agreed to sell health-care subsidiaries that provide nursing, mobile X-ray and hospital consulting services to a new company formed by the principals of Kidd Kamm & Co., a private investor group in Beverly Hills.