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June 6, 1996


UPMC using lasers to unclog heart arteries

The University of Pittsburgh Medical Center is one of 10 centers across the country participating in a study of a new laser technique to open totally blocked coronary arteries. Two hundred patients nationwide will undergo the procedure. The new technique can vaporize and eliminate blockages where other techniques fail.

Unlike other lasers, the laserwire used in the TOTAL (Total Occulsion Trial with Angioplasty using a Laser) Trial does not produce heat, which can cause damage to the artery. The laserwire produces a burst of ultraviolet light which lasts for one-millionth of a second. The light is transmitted through fiber optics directly to the blockage, creating a "pilot hole." Routine laser catheter and balloon catheter treatment can then be used to eliminate the rest of the blockage, and return the artery to close to its original size.

According to Howard Cohen, director of the UPMC Cardiac Laser Center, this new technique may eliminate the need for many people to undergo bypass surgery when routine angioplasty and medical therapy are ineffective. Currently, bypass surgery is the only alternative when these techniques fail.


Abbott Labs teams up with UPMC researchers

The research of investigators Said Sebti and Andrew Hamilton was recently given a boost when they entered into a research agreement with Abbott Laboratories, a diversified health care company. The pair will continue their research into novel cancer drugs that block the activity of Ras, an oncogene.

An oncogene is a gene that, when it is turned on, causes cancer. The Ras oncogene is highly studied by researchers because it is involved with more than 30 percent of all human cancers, with the k-Ras form being the one that is most responsible. According to Sebti, an associate professor of pharmacology, the study of some promising Ras-blocking agents will be advanced by this new partnership. The team hopes to continue the success they achieved in designing of "nonpeptide peptidomimetics" in 1995. These agents are designed to mimic the actions of peptides, which are known to arrest the activities of some forms of Ras, without breaking down as quickly as peptides. Hamilton, chair of chemistry, noted that rather then preventing farnesylation, the team blocked a different enzymatic pathway, gernaylgeranylation, which led to a greater inhibition of k-Ras activity.

According to Ronald B. Herberman, associate vice chancellor for research, Health Sciences, and the director of the University of Pittsburgh Cancer Institute, the new partnership between the researchers and Abbott Labs indicates a confidence that the line of investigation by the team is expected to result in significant therapeutic advances for cancer. Under the terms of the agreement, Abbott has received certain rights to patents and other intellectual property invented by Sebti and Hamilton. The University will profit as well, by receiving a licensing fee, as well as milestone payments and royalties relating to further development and commercialization of the intellectual property.


Strain of hepatitis C virus doesn't affect survival rates

Researchers at UPMC have concluded that, contrary to other reports, the particular strain of the hepatitis C virus that a patient is infected with does not affect the rate or severity of a recurrence of the disease. Recent European studies suggested that the particular strain of the virus did affect a patient's chances of having a recurrence.

The UPMC findings were presented by Hugo Vargas, a fellow in the division of gastroenterology and hepatology, last month during Digestive Disease Week, a series of meetings attended by 10,000 specialists in gastrointestinal diseases.

In the United States, 25-30 percent of liver transplants are done on patients with hepatitis C. In nearly half of those patients, the virus is likely to recur a few years after the transplant.

There are as many as 25 genotypes and subtypes of the hepatitis C, with some forms being more prevalent or virulent in different parts of the world. According to Vargas, the UPMC study showed that there was no difference in the rate or the severity of the recurrence based on this genotype variance.

However, the researchers did find that while the overall survival rate after 5 years is 75 percent, patients from the Middle East have a better chance of survival. Half of those patients were infected with genotype 4, which is most commonly found in Africa and the Middle East, and in eight of the patients, the researches discovered at least five new strains of genotype 4 virus. Further research is needed to see why genotype 4 patients have higher survival rates.

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