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June 10, 2004

Research Notes

Studies may enhance understanding of sports-related injuries, performance

Studies conducted at Pitt’s Neuromuscular Research Laboratory (NMRL) may provide better understanding of the prevention and treatment of certain sports-related injuries and athletic performance.

Pitt researchers presented findings of several studies last week at the American College of Sports Medicine 51st annual meeting in Indianapolis.

The following are summaries of three NMRL presentations.

Throwing athletes’ shoulders differ from non-throwers’

Pitt research showing that throwing athletes have certain differences in shoulder blade position and orientation compared to non-throwing athletes may help doctors better understand and manage shoulder injuries in throwing athletes.

While examining injuries associated with the throwing motion in throwing athletes, athletic trainers and doctors routinely evaluate the position, orientation and three-dimensional movement of the shoulder blade or scapula. The scapula acts as the stable base of support between the arm and trunk while still allowing for the high degree of movement needed from the upper extremity during the throwing motion. However, minimal research has been done to quantify scapular position and orientation in throwing athletes compared to non-throwing athletes.

A study at Pitt’s NMRL has shown that experienced throwing athletes do indeed have certain scapular position and orientation differences compared to non-throwers, suggesting that throwers develop chronic adaptation for more efficient performance of the throwing motion.

The findings may provide clinicians with a better understanding of types of adaptations that may be observed in normal, healthy throwing athletes and thus potentially lead to more effective injury prevention and treatment.

A two-year grant from NFL Charities provided support for the study, which enrolled 21 healthy, uninjured throwing male athletes to compare with a control group of 21 healthy, uninjured male non-throwers. All study subjects performed specific related motion tasks while sophisticated biomechanical and neuromuscular assessment tools monitored certain scapular positioning, orientation and movement during the assigned tasks.

Stronger hip muscles = better golf

Golfers with stronger hip muscles also reported having better golf performances compared to golfers who showed weaker hip muscles in an NMRL study.

To determine if there is any difference in hip strength among golfers with different proficiency levels, the relationship between hip strength and golf handicap, and between hip strength and self-reported driving distance, researchers enrolled 82 golfers and divided them into three groups based on their proficiency levels according to self-reported driving distance and handicap. Using laboratory neuromuscular strength assessment tools, researchers studied each participant’s isometric hip abduction and adduction strength in side-lying with the hip joint in neutral position for both legs.

Left hip abduction strength was significantly higher in the better golfers’ groups, and in the best golfers’ group, all hip movements tended to be stronger. The results of this study demonstrate the importance of hip musculature for stability of the trunk and the balancing forces transferred between lower body and upper body extremities during the golf swing. This may be related to overall golf performance.

Unplanned reactive jumps should be included in ACL research

Injuries to the ACL (anterior cruciate ligament), the main stabilizing ligament in the knee, are common among athletes, up to eight times more common in female athletes. Research into the risk factors of non-contact ACL injury prevention often calls for study participants to perform planned vertical stop-jump tasks.

However, NMRL investigators say that ACL injury prevention research protocols should include unplanned reactive jumping tasks to better simulate actual athletic competition.

In the Pitt study, 26 male and female basketball players performed both pre-planned stop-jump tasks and unplanned stop-jump tasks upon reaction to sudden visual cues during the jump, which represents more actual athletic competition. During the reactionary jumps, the players demonstrated a decreased knee flexion angle with a greater deceleration component compared to when they performed pre-planned stop-jump tasks.

The findings suggest that reactive jumping tasks should be included when researchers are trying to determine the at-risk movement patterns for non-contact ACL injuries.

A grant from the Jewish Healthcare Foundation provided support for the study.

 

To learn more about these and other research projects at Pitt’s NMRL, access www.pitt.edu/~neurolab/. The facility is housed within the University of Pittsburgh Medical Center’s Sports Performance Complex, in the Center for Sports Medicine. NMRL faculty include those from the sports medicine program at Pitt’s School of Health and Rehabilitation Sciences and the orthopaedic surgery department at Pitt’s School of Medicine.

AHA awards postdoctoral fellowship

The American Heart Association has awarded Wendell Meira a postdoctoral fellowship for the period of July 1, 2004, through June 30, 2006.

Meira is a fellow in the laboratory of Karen A. Norris in the Department of Immunology. His project title is “Genetic Immunizations Against Chagas’ Disease.” The award totals $74,000.

Proteins Bond Together to Protect DNA

Proteins that make up the hollow capsid of bacteriophage HK9 protect the virus’ DNA from harm by quickly mobilizing to form links that securely bind the capsid proteins together as DNA is inserted.

Researchers at Pitt and The Scripps Research Institute are examining this activity of HK97, a virus that infects bacteria. HK97 has properties similar to some animal viruses, including herpesviruses. The researchers’ findings were reported in the June 4 issue of Molecular Cell.

Robert Duda and Roger Hendrix, members of Pitt’s Bacteriophage Institute and assistant professor and professor, respectively, in the University’s biological sciences department, are studying how viruses are assembled in collaboration with researchers at The Scripps Research Institute in La Jolla, Calif.

Previous research has shown that HK97 – first isolated from pig dung by a rice geneticist in Hong Kong – has unique properties. Typically, as bacteriophages mature, the DNA-containing capsid is strengthened by many weak contacts between capsid proteins or by extra proteins that act as glue.

In HK97, however, the mature capsid is stable because the proteins form chemical bonds, or cross-links, with each other as the capsid expands. HK97 was the first bacteriophage discovered to form these stabilizing cross-links.

Researchers now know that HK97 begins to form cross-links early in the maturation process, at the same time that the capsid expands in size and DNA is pumped inside. It was previously thought that the cross-links were the last step in the process. This research may help elucidate how and why proteins change their shape, interact with other proteins, and assemble themselves.

“Once we understand in detail how viruses get assembled from their parts, we can start to think about how we might use that knowledge to sabotage the life cycles,” said Duda.

Researchers also are interested in a packaging signal that directs a maturation enzyme, called a protease, to its site of action inside the capsid during its assembly. If researchers determine the mechanism of the packaging signal, Duda speculates, then it possibly could be used to entrap useful biomolecules into nanoscale protein spheres.

HK97 bacteriophage is similar to the bacteriophage lambda, one of the most well-studied bacteriophages. They both have the characteristic long tail with a balloon-like capsid, which stores the DNA that is injected into the host bacteria. The capsid serves to protect the DNA during transport from one host to another.

UPCI researchers present findings

Researchers from the University of Pittsburgh Cancer Institute presented findings from several studies at the annual meeting of the American Society of Clinical Oncology, June 5-8 in New Orleans.

Highlights included the following:

Vaccine elicits immune response in metastatic melanoma patients Results from the largest multi-site study to date evaluating a peptide-derived therapeutic vaccine for melanoma show promising evidence that researchers can activate a patient’s own immune system to fight advanced cases of the deadly skin cancer.

“This is the first time we have evaluated peptide-derived melanoma vaccine results from a multi-center cooperative group trial,” said John Kirkwood, principal investigator of the study, professor of medicine at Pitt and director of UPCI’s Melanoma Center. “We have found evidence that the vaccine stimulates an immune response and that it is reasonable to evaluate the correlation between disease course and immune response for patients who receive the vaccine.”

The phase II study, funded by the National Institutes of Health and the Schering Plough and Immunex Corporations, involved 120 patients with metastatic melanoma and researchers from 30 research institutions across the country.

Malignant melanoma is one of the deadliest forms of skin cancer. An estimated 54,200 new cases are expected this year, and 7,600 deaths from the disease.

Pancreatic cancer vaccine safe, stimulates immune activity

Results from a phase I study to evaluate the toxicity of a potential therapeutic vaccine for pancreatic cancer demonstrate that patients can safely tolerate multiple doses of the vaccine.

Preliminary evidence indicates that the vaccine, a synthetic version of a molecule expressed on pancreatic tumor cells, in combination with patient’s own antigen-presenting cells (known as dendritic cells), boosts immune activity in pancreatic cancer patients.

Only half of common cancer drug activated

Only half of the delivered dose of a commonly used chemotherapeutic agent may be activated in cancer patients, according to a study that analyzed data from 31 cancer patients given 30-minute infusions of gemcitabine.

The study found that while approximately 50 percent of the gemcitabine dose was likely to be converted to active metabolites, the other 50 percent was likely to be inactivated, and as a result, possibly not contribute to a therapeutic effect.


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