Johns Hopkins Gazette: July 10, 1995


Medical News

Mutation linked to non-
inherited colon cancer

     Building on research conducted by scientists in the United
States and Italy, investigators at the Howard Hughes Medical
Institute at the Johns Hopkins Oncology Center have linked a new
genetic mutation to non-inherited colon cancer.

     In findings reported in the June 30 issue of Science,
scientists from the Istituto di Ricerche di Biologia Molecolare
in Rome and the Howard Hughes Medical Institute at Duke
University independently identified a mismatch repair gene known
as GTBP.

     The GTBP gene is the fifth human mismatch repair gene
identified by scientists including Bert Vogelstein, Clayton
Professor of Oncology at Hopkins.  While mutations of the
previously identified genes were linked to an inherited form of
colon cancer known as hereditary non-polyposis colon cancer,
Vogelstein's team found that alterations of the GTBP gene were
involved only in non-inherited, or sporadic, colon cancers, which
account for the majority of colon cancers worldwide. 

     Mismatch repair genes like GTBP act as proofreaders, looking
for mistakes in the DNA copying process and correcting them.  DNA
is assembled like a ladder, with chemical compounds called
nucleic acid bases pairing to form rungs on the ladder. The four
bases that are the molecular building blocks of DNA are
symbolized by the letters A, T, C, and G. A always pairs with T,
and C always pairs with G. Sometimes, however, mistakes in the
copying process occur, and the bases become mismatched. It is the
job of proteins produced by the mismatch repair genes to correct
the mistakes before the error is passed on to the next generation
of cells. Mutations in mismatch repair genes allow errors to go
unchecked, resulting in the inability to copy DNA correctly and
causing an accumulation of cellular errors that ultimately lead
to cancer.

     Over 500,000 individuals are diagnosed worldwide with colon
cancer each year. When diagnosed early, cure rates are high, but
when the disease spreads outside the colon, survival rates
decrease dramatically. The researchers believe this newly
identified mutation also may have future implications as a
diagnostic marker for the early detection and treatment of colon
cancers and potentially other cancers.

Forgoing care for 
AIDS-related disease costly

     The failure of many people infected with HIV-1 to get
preventive treatment for an AIDS-related pneumonia is needlessly
costing lives and increasing medical costs, according to a study
at The Johns Hopkins Medical Institutions. 

     These individuals get a disease called Pneumocystis carinii 
pneumonia because they either never get treatment for it or fail
to take medicine prescribed by their doctors, said the study's
authors in a report published in the April issue of Chest.

     The authors said that if their findings apply to other
hospitals in Maryland, the failure of HIV-infected individuals to
get preventive treatment for PCP may have cost the state almost
$5 million in 1992.  

News from Homewood

Getting ice cream 
for donating blood

     Employees who register to donate blood in the university's
summer blood drive--scheduled from 9 a.m. to 3 p.m. on Wednesday,
July 12, in the Glass Pavilion--will receive a coupon for one
free frozen yogurt cone at the Levering Market. In addition, the
name of each participant will be included in a drawing for five
gallons of Ben and Jerry's ice cream_with toppings--to be
delivered to their academic or administrative department. To
register, call Peggy Jones at 516-8039.

Computer software helps 
escort vans "drive right"

     In an effort to reduce the number of escort and security van
accidents and complaints of reckless driving, the Homewood
security office has installed a new computer program to keep
track of violations and violators.

     The "Drive Right" program both sets off an alarm in the van
if the driver exceeds the speed limit and downloads the
information into each shift's log.

     A driver with three violations will lose his or her job,
said Patrick Bearry, a sergeant with Homewood security for the
past three years and supervisor of the 30-van security escort

     The Homewood escort and security vans--not the intercampus
shuttle buses--carry approximately 67,000 passengers yearly on
and around the Homewood campus, said Bearry, a National Safety
Council defensive driving instructor. He bought the computer
program, he said, because of many reports of excessive speed and
reckless driving within the past year, which have resulted in
near misses as well as accidents.

     In a case last year, a van carrying students along winding
San Martin Drive was totaled after the driver lost control
traveling 55 mph over the speed limit. No one was injured.

     Bearry trains about 500 students each year to drive the
escort vans, and he believes the "Drive Right" program will be
good motivation for them to drive much more safely.

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