David S. Sheridan

Catheter Pioneer

David S. Sheridan, 95, who is credited with inventing the modern disposable catheter and was dubbed the "Catheter King" in 1988 by Forbes magazine, died April 29 at his home in Argyle, N.Y. No cause of death was reported.

Until World War II, urethral catheters were usually made of braided cotton strings that looked like shoelaces and were laminated repeatedly. And they were used repeatedly. Mr. Sheridan, who only had an eighth-grade education, built a machine that made disposable plastic catheter tubes. He later figured out a way to produce plastic catheters with wider ends and put a line of radioactive paint down a catheter that would show up on X-rays.

He started in the catheter business in the 1930s when a friend persuaded him to put up his $35,000 in savings to begin U.S. Catheter and Instrument Corp. He left that company in 1945 but later built and sold three more catheter companies. He held more than 50 patents and also pioneered a plastic endotracheal tube used routinely in surgery.

Sam White

Biomedical Researcher

Sam White, 91, a pioneer in biomedical research who helped design medical tests for the first U.S. astronauts, died April 26 at a hospital in Albuquerque. He had respiratory ailments.

Dr. White, the brother of late U.S. Supreme Court Justice Byron White, organized a team approach to examining and testing the astronauts at Lovelace Medical Center in Albuquerque, where he worked for more than 30 years. Dr. White researched aging, memory loss, hypothermia, cosmic rays, geology and pollution of the upper atmosphere. He also was known for making instruments to treat patients or to conduct experiments.

The Smithsonian Institution asked Dr. White to borrow the slide-rule-like device he designed to calculate the shock wave of the first atom bomb for an exhibit on the 50th anniversary of the bomb.

John W. Kirklin

Heart-Lung Researcher

John W. Kirklin, 86, who helped perfect the heart-lung bypass machine at the Mayo Clinic in the 1950s, died April 21 at his home in Birmingham of complications of a head injury in January.

At the Mayo Clinic in Rochester, Minn., Dr. Kirklin refined the Gibbon heart-lung machine and in 1955 performed the first series of successful heart surgeries using the improved device. During his 45-year career, Dr. Kirklin developed surgical techniques for a variety of heart defects and co-wrote the textbook "Cardiac Surgery."

Recruited in 1966 to direct the University of Alabama's surgical program in Birmingham, he helped turn the city from a racially troubled steel center into a prominent medical site. The Kirklin Clinic, an outpatient center that opened at the university in 1992, was named in his honor.

Fred C. Davison

University President

Fred C. Davison, 74, the former University of Georgia president who guided the state's flagship school from 1967 to 1986, died April 28 at a hospital in Augusta, Ga. He had cancer.

Dr. Davison, a Georgia alumnus, was dean of the college of veterinary medicine and vice chancellor of the University System of Georgia before being named president of the university. He made scientific research a top priority.

While he was president, the university's overall budget grew fivefold, from $72.5 million to $370 million. The research budget soared from $15.6 million to more than $96 million. Graduate enrollment more than doubled, and doctoral degrees awarded annually rose from 123 to 300. Student enrollment climbed from 15,600 to 25,000, and 15 major buildings were erected.