Call it growing pains. Blame it on bad luck or bad weather. Any way you look at it, the last 12 months have been a discouraging time for Insituform East of Landover, a company with a tongue-twister name and a business that might be described as "mid-tech." That's somewhere between high-tech and low-tech.

Insituform East can repair old water and sewer pipes without digging them up. Insituform inserts a plastic pipe into an old pipeline; after the plastic is heated, it becomes a tough new pipe within the old pipe.

With many of the nation's pipelines sorely in need of repair, Insituform stock attracted many local investors who figured the firm's services would be in heavy demand. Indeed, Insituform profits flowed nicely in fiscal years 1982 through 1985. Then, in 1986, the business sprang a leak.

Although 1986 sales rose to $11.9 million, a gain of 22.7 percent, profits fell to $946,0000, a loss of 22.2 percent.

And that sent those closely watched per-share earnings down to 22 cents from 28 cents.

Little wonder that Arthur G. Lang III, president of Insituform, called 1986 a "bittersweet" year. Last fall, when Lang was asked about the company's performance, he acknowledged that mistakes were made on several projects and, in some cases, work had to be redone. Newer workers lacked experience, there were weather delays and a key company executive had died.

Things would get better, Lang predicted.

Well, nine months later, the profit picture still has not improved. In fact, it has worsened. But Lang said he remains confident that the company's performance will improve.

For the first nine months of fiscal 1987, Insituform again saw its sales improve -- rising to $10.3 million for a gain of 12.8 percent. But again profits took a beating, coming in at $307,000, a drop of 78 percent from a year earlier. Per-share earnings for the nine months fell to 6 cents from 24 cents.

All of that does not seem to bode well for the company's performance in 1987, which ends June 30. Clearly, 1987 is going to be even more bittersweet than 1986.

But the numbers may not tell the full story about Insituform, said analyst Mark Hayes of Shearson Lehman Bros. The situation at Insituform is "markedly improved," Hayes believes. One key reason is that the company has hired five experienced executives to help manage its growing business.

"They've deepened and broadened the management team," Hayes said.

Hayes view is signficant because he was the analyst who issued a "sell" signal on the stock last August. He did so because he heard the company was having trouble getting crews into the field and he expected profits to turn down.

Hayes said that if Insituform can get its management operating effectively, the company should be able to get plenty of work from municipalities. "They're dealing with a gold mine. The just need to get it mined," he said.

Hayes said he was impressed with the new three-year, $12 million contract awarded Insituform by its best customer, the Washington Suburban Sanitary Commission (WSSC). Insituform said the first $4 million will help boost its 12-month backlog of work to $9 million from $5.6 million.

Insituform shares closed Friday at $8.50, down 38 percent from their price of $13.75 on Jan. 1.

Choppy times are nothing new to Insituform. Its stock was down 63.8 percent in 1984, up 259.6 percent in 1985 and up 158.8 percent during the first half of 1986. Then, the firm's troubles began and Insituform wound up 1986 with a gain of only 29.4 percent.

What's next for this troubled company?

Hayes said he was not yet prepared to make a recommendation on the stock, which he thinks is about as low as it is going to get. Although he fully expects Insituform's business to improve, Hayes is waiting to see it happen. "Until there is evidence of consistency in profit improvement, I'm not in a position to be more positive, he said.

If it is true that nothing succeeds like success, consider what has happened recently to Data Measurement Corp. of Gaithersburg. First, the company turned in a 1986 performance that saw its profits rise 57 percent. Then, in its 1987 first-quarter statement, DMC reported that profits increased four-fold over a year earlier. After that, DMC announced it would make an acquisition that could vastly expand its business. And finally, DMC officials picked up Business Week magazine last week to find that their firm was ranked 48th in a list of the 100 best small-growth companies in the nation.

Naturally, that stirred considerable investor interest in the company, whose stock had traded in a narrow $9 to $11 range for a year. DMC shares bounced up to $13 on May 22, about the time the Business Week article was circulating widely.

In week after that, the stock continued to move up and closed Friday at $16.75, up 52.2 percent over its recent $11 high.

Few people could be happier about all this than the folks at Wachtel & Co., Washington, which took DMC public in 1981 at $2.50 a share, adjusted for several splits.

Chairman Sidney B. Wachtel and John Sanders, who is a member of the DMC board of directors, were at last week's annual meeting to cheer the company's progress. Wachtel & Co., a large holder of DMC stock, has been selling some of its shares as the price rises, thereby reaping the rewards that derive from years of investment patience.

President Dominique Gignoux told stockholders he is optimistic about 1987 and said he expects sales this year to be in the $10 million to $14 million range, compared with $8.3 million in 1986.

DMC is planning to acquire the instrument systems division of Fife Corp. of Oklahoma City. Fife is a subsidiary of Rexnord Inc., which is, in turn, a subsidiary of Banner Industries. No price has been announced for the Fife acquisition but DMC is thinking about another stock offering in connection with the proposed acquisition.

DMC and Fife manufacture computerized measurement systems. Most of DMC's customers are in the metals business. Fife's customers produce fiberglass, flooring and roofing materials, paper, plastics, rubber and vinyl. The acquisition would represent a major expansion of DMC's customer base.

The thrift industry continues its expansion into investment services. Meritor Savings Bank, which has 20 branches in the metropolitan area, will soon offer its depositors access to five funds in the Merit Mutual Funds family. Merit is a subsidiary of Meritor Financial Group. The service will begin July 1, reports Joseph F. Kissel, president of Sav/Vest Securities Corp., of Philadelphia. Depositors will be able to transfer money from their accounts directly to the mutual funds.

Kay Jewelers of Alexandria, trading under the symbol KJI, has moved from the American Stock Exchange to the New York Stock Exchange. Michael R. Lavington, president of Kay Jewelers said that his firm is seeking broader exposure for its stock and that some institutional investors prefer to deal with stocks listed on the Big Board. Kay Jewelers operates 452 stores in 34 states. Kay Corp., which has its headquarters in New York, is still listed on the American Stock Exchange. Kay Corp. is an international commodities-trading firm, and the former parent of Kay Jewelers.

Also moving to the Big Board from the Amex is Washington Homes of Waldorf, an old-line home-building firm that owns 87 percent of the stock in the Washington Savings Bank. Washington Homes said it is seeking wider exposure for its stock, one-third of which is owned by institutions.

With interest rates rising and bond prices falling, mutual fund companies reported heavy selling in April. They also saw a large shift of money from bond funds, taxable and nontaxable, to money market funds. At T. Rowe Price Associates in Baltimore, Steve Norwitz reported, bond funds lost about 10 percent of their $4.5 billion in assets, or about $450 million. Most of it went into money market funds while some of it went into international bond funds, Norwitz said.