When it comes to investors, Samaritan Pharmaceuticals is pleased to explain how cutting-edge treatments it's developing will help patients suffering from AIDS, Alzheimer's disease and cancer.

The Las Vegas company has run television ads on CNBC aimed at investors, even though the American Stock Exchange in November notified the company that its listing was at risk because shareholder equity and operating profits didn't meet the required thresholds.

However, Clark County District Court judges have hidden from the public four lawsuits involving the company or its top executives by sealing those case files.

No other company or individual had more Clark County civil suits sealed than Samaritan since 2000, but there also are dozens of doctors, health-care professionals and medical-service agencies listed as litigants in lawsuits sealed during the past six years.

Most lawsuits in Clark County are open for public review, but judges for years have sealed cases. No information is available to the public on those sealed lawsuits, but the Review-Journal obtained limited information about some. Many litigants are wealthy or wield influence in Las Vegas politics, business or the courts.

Judges said the state Supreme Court's controversial 1995 Whitehead ruling gives them authority to seal cases, but critics said the practice is unconstitutional.

The most recent lawsuit involving Samaritan was filed in January 2006 against LabConnect, a company that Samaritan selected a year earlier to "provide central lab testing services for its upcoming Monotherapy trial for HIV patients," according to a Samaritan press release circulated at the time.

The lawsuit was sealed by a judge the same day it was filed, and the court closed the case in October, according to court records obtained by the Review-Journal.

Since a judge sealed the case, the public has no way of knowing what the dispute was about, whether it involved the testing of the drug, which judge sealed the case or why.

Two other sealed lawsuits involve disputes between company executives and a former associate, Dr. Alfred T. Sapse.

Samaritan executives referred the Review-Journal's questions to attorney Terry Coffing, and Sapse couldn't be reached for comment at his Las Vegas home.

However, after the Review-Journal's series on sealed lawsuits began Sunday, Sapse telephoned and said his lawsuits alleged wrongdoing on the part of Samaritan executives. He said the sealed lawsuits alleged that company president Janet Greeson misled executives about her background before she was hired and that others embezzled money.

The lawsuits were settled, with both Sapse and Samaritan agreeing that neither would pursue further legal action, he said. Sapse added that he agreed to sealing the cases because legal bills left him penniless, and he couldn't risk being sued. Sapse said he decided to talk about the sealed cases now because the Review-Journal "had the guts to write about something that was sealed. ... At this moment, the world needs to know what really happened."

Coffing said the lawsuits involving Sapse were sealed at Samaritan's request. He characterized Sapse as a disgruntled former executive who departed the company in the late 1990s and then filed lawsuits intended to embarrass former colleagues and hurt the company, Coffing said. He declined to give details of those allegations.

Sapse "is the type of guy who takes anything that comes out of his mouth and puts it on a piece of paper. ... and then tells you it must be true because it is on a piece of paper," Coffing said. "It's all BS, and we wanted to stop the BS. The judge understood our position and sealed it (the cases)."

The federal Food and Drug Administration in November sent Sapse a notice that he was in violation of federal law after an inspection of his business, StemCell Pharma Inc., which he operated out of his Las Vegas apartment. The inspection found Sapse had obtained placentas from at least one doctor, processed the tissue and implanted stem cells into at least 16 people with various diseases.

Also, Sapse in late 2005 tried to gather signatures on a petition aimed at convincing Nevada lawmakers to legalize his method of using stem-cell transplants to cure disease.

In 1977, Sapse helped convince Nevada lawmakers to legalize Gerovital, a drug that supporters touted as an anti-aging agent. Subsequent studies have not found Gerovital to have any therapeutic value.

Other sealed lawsuits involve other medical companies, such as:

• A lawsuit filed against the Bayer Corp. in January 2002 by Carol Marston and the Estate of Gerald Marston was sealed by a Clark County judge. Carol Marston couldn't be reached for comment.

The civil lawsuit surfaced five months after Bayer in August 2001 withdrew from U.S. markets a cholesterol-lowering drug known as Baycol, and five years before officials in Nevada and 29 other states announced an $8 million settlement with Bayer over its marketing of the drug.

The settlement reached last month was in response to concerns that Bayer didn't adequately warn consumers of risks associated with Baycol, according to the Nevada attorney general's office. Nevada's share of the settlement was $200,000.

Bayer first marketed Baycol in 1988 but later learned the drug posed a "significantly" higher risk than other, similar drugs, according to the attorney general. Although Bayer notified the FDA of the risks, state officials allege the company didn't do enough to warn consumers of the dangers, according to the attorney general.

According to Bayer's online Stockholders' Newsletter for the third quarter of 2006, in November there were 2,270 Baycol lawsuits pending and that "Bayer had settled 3,142 (Baycol) cases worldwide without acknowledging any liability."

• A lawsuit sealed in September was filed by the family of Howard Hirabayashi, who was selected the Nevada Restaurant Association's 2003 Restaurateur of the Year and who was associated with the Hamada Japanese restaurants in Las Vegas and Los Angeles.

According to Nation's Restaurant News, Hirabayashi died in July 2003 at age 43 of an apparent heart attack.

His family in October 2004 brought a lawsuit against St. Jude Medical Inc., which sells devices and therapies for heart conditions, such as pacemakers and replacement heart valves, according to court records.

According to the company's online 2005 Financial Report published last year, at least two products prompted litigation in recent years.

The company in 1997 started marketing mechanical heart valves that incorporated Silzone coating because it believed the coating would reduce the risk of bacterial infection, according to the financial report. Subsequent studies showed patients with a Silzone-treated valve had a higher incidence of leaks than patients whose valves didn't include Silzone, the report states.

Plaintiffs alleged either bodily injury or that they required more monitoring than other heart patients, according to the financial report.

The other product was a device known as the Symmetry Bypass System Aortic Connector, according to the financial report. A month before the Hirabayashi lawsuit was filed, St. Jude launched a plan to stop manufacturing the device after lawsuits were filed, according to the financial report.