TU International Inc., the Falls Church computer company that went through a reverse acquisition last year and has been trying to straighten out the paperwork ever since, yesterday posted its results for last year, the six months ended Dec. 31 and for the third quarter.

During 1982, the year the rapidly growing private firm Terminals Unlimited was acquired by Duke of Energy Corp., TU had revenue of $13 million and profits of $534,698 (8 cents a share), with 6,307,697 shares outstanding.

In the first half of fiscal 1983, TU earned a scant $1,684 on revenue of $11.5 million.

Third-quarter profits were $122,000 (1 cent) on sales of $5.7 million. TU did not give comparative figures for previous reporting periods.

David M. Owens, head of TU and founder of Terminals Unlimited, said the company has made progress since he took the chief executive post. "All subsidiaries are now operating profitably and we expect them to remain profitable."

Universal Security Instruments Inc. of Resisterstown, Md., a manufacturer of security systems and telephone equipment, lost $800,000 during the most recent quarter, on sales of $2.9 million. During its fourth quarter last year, the firm lost $225,000 on sales of $4.9 million.

For fiscal year 1983, ended March 31, the firm lost $2.5 million on sales of $15.6 million. This compared with the firm's net gain of $60,000 on sales of $18.5 million in 1982.

Bresler & Reiner Inc., a D.C.-based real estate developer and operator, reported profits of $298,000 (27 cents) in the first quarter, compared with $235,000 (21 cents) last year. Revenue declined slightly to $3.1 million from $3.3 million.

BTR Realty Inc., a Baltimore real estate firm of which Fair Lanes Inc. owns 47 percent of the stock, earned $148,826 (7 cents) in the first quarter, compared with $165,228 (7 cents). Per-share earnings have been adjusted for a 2-for-1 stock split in December. Revenue increased to $2.6 million from $1.4 million.

Isomet Corp. of Springfield reported first-quarter profits of $21,000 (1 cent), compared with $163,000 (11 cents) last year. Revenue declined to $744,000 from $1.1 million.