Volume 4, Issue 2: June 2009
Paula K. Shireman, MD
We are seeking successful strategies for muscle regeneration — ultimately
improving survival rates in traumatic injuries.
In their studies, they have used several mouse models: hind limb ischemia, toxic injury and tibialis anterior muscle defect to derive a more complete understanding of how angiogenesis and muscle regeneration occurs after injury. A better understanding of how muscle regenerates could be used to recapitulate this complex process to provide soft tissue coverage after traumatic injury.
Tissue engineering strategies utilizing skeletal muscle offer a unique opportunity to advance the field of regenerative medicine. Most research has been performed in injured brain, spinal cord and cardiac tissues — three tissues that do not normally regenerate in adults. In addition, most patients with cardiac and brain diseases are elderly with multiple comorbidities that are also associated with impaired tissue regeneration.
Alternatively, skeletal muscle regenerates throughout the lifetime of humans and importantly, young patients after civilian and military trauma can experience extremity injuries that require soft tissue coverage for limb salvage. Adult myogenic progenitor cells can easily be isolated from individual patients, thus, there is a readily available source of progenitor cells and a need for skeletal muscle regeneration in young patients with few comorbidities. Furthermore, successful strategies for muscle regeneration in young patients may provide insights that may improve regeneration techniques in elderly patients and in tissues that do not regenerate in adults. Surgeons can play an important role in this process.
marrow can be used to regenerate muscles and capillary networks in
When Dr. Shireman is not advancing the frontiers of science,
she focuses on her family:
Dr. Shireman's children have attended the San Antonio Chinese Culture Institute since 2006. The goals of this organization are to introduce Chinese culture through activities and instruction in Mandarin Chinese. As she is a multi-generational American being able to trace roots back to the Revolutionary War, it is exciting for her to learn with her children about another culture. The family has many wonderful Taiwanese friends and have all grown from our experiences. Further, she can't wait until the children are older and can act as translators for future family trips!
Mark Muir, MD
Research mentors: Stephen M. Cohn, MD, Trauma Surgery, and Joel Basemen, PhD, Microbiology, University of Texas Health Science Center San Antonio
Current research: Mycoplasma pneumoniae infection in ventilator-associated pneumonia and acute lung injury. Dr. Muir is the recipient of NIH T-32 funding, as well as a Doris Duke Clinical Research Fellowship. His research is conducted at both the UT Health Science Center San Antonio and University Hospital in San Antonio, Texas.
This research project could greatly affect the care of critically ill surgical patients, in particular those patients requiring prolonged mechanical ventilation. The results of this study could lead to improvements in the diagnosis and treatment of pnuemonia in severely injured trauma patients, and perhaps in other arenas of critical care as well.
Current research results suggest that a significant number of ICU patients undergoing bronchoscopy have a pulmonary Mycoplasma pneumoniae infection. The prevalence of mycoplasma in this ICU population is similar to that observed among other cohorts with various chronic lung diseases, but the clinical relevance of these findings remains to be elucidated.
Life away from the lab
During the past fall and summer, Dr. Muir played on a recreational
league softball team. The rewarding moment
came in the last game of the regular season when they got their first win.
But, tragically, Dr. Muir was sitting out the game with a knee injury.
He's also started jogging again, something he really enjoys but hasn't
done regularly since medical school.
Shaun Gifford, MD
Research mentor: Lt. Col. Todd Rasmussen, MD, Vascular Surgery, Wilford Hall USAF Medical Center, Lackland Air Force Base, Texas
Dr. Todd E. Rasmussen went to undergraduate school at the University of Kansas, followed by medical school at the Mayo Clinic in Mayo, MN. He took an HPSP scholarship and did his residency in the Air Force at Wilford Hall Medical Center. He completed his vascular surgery fellowship at the Mayo Clinic and was appointed assistant professor at the Uniformed Services Medical School in Bethesda, MD. After a few years of clinical practice, Dr. Rasmussen transferred to Wilford Hall Medical Center where he became the chief of the Vascular Surgery Division. He has deployed twice to Operation Iraqi Freedom as a vascular surgeon and has brought his experience home to the lab. He now runs a very productive vascular trauma research lab with three residents, two clinical nurses, and a technologist who work on several projects. Dr. Rasmussen is widely published in trauma and vascular journals, has been invited to speak all over the world, and is devoted to mentoring residents through their research.
Current research: Dr. Gifford is the recipient of a $250,000 US Air Force Surgeon General research award; his research is conducted at both Wilford Hall USAF Medical Center and the US Army Institute of Surgical Research at Brooke Army Medical Center, Ft. Sam Houston, Texas. His research focus has been on the use of temporary vascular shunts to restore blood flow to an injured limb, as well as on ischemia reperfusion and the temporal impact of flow restoration on injury.
The impact of Dr. Gifford's work has direct applicability to trauma and vascular subspecialties. Through his projects, Dr. Gifford has been able to show that not only is early restoration of flow beneficial, but that the use of a synthetic tube early in care to limit ischemia has no harmful effects, and may actually improve outcomes.
Historically, shunts have been utilized in specific instances of limb ischemia and reserved for the most difficult situations. The current war in Iraq has witnessed a volume of extremity vascular injury not seen since the Vietnam War. In close connection to this, the use of the temporary vascular shunt has grown immensely. From these experiences and his research, he now believes that shunts have more of a benefit then once perceived, and that they should be placed earlier in the care of an ischemic limb. Drs. Rassmussen and Gifford hope that their findings will push surgeons to deal with extremity injury more aggressively and not approach limb ischemia casually by allowing the historically accepted "6 hours" of warm ischemia prior to intervening.
In the past year or two what is the most important/interesting/exciting
finding in your research?
Both of Dr. Gifford's research projects incorporated these questions. The research team were able to scientifically show that delaying placement (or reestablishing flow later and allowing for longer ischemic times) led to worse injury. Although intuitive, this had not been shown before. More importantly, and actually a little more exciting, was the fact that they were able to show that shunt use did no harm. Opponents have been discussing for years the problem with shunt placement. Their fears concerned the expertise needed, the potential for dislodgement, the injury to the intima from shoving a tube in a vessel, among others. In Drs. Rassmussen's and Gifford's follow-up study, they showed that there was no added detriment in patients who had shunts utilized, and in fact, some individuals did better.
What made it better was that these shunts were placed in a tent in Iraq by general, trauma, and orthopaedic surgeons.... without vascular training and they still did no harm!
These results were presented in Tucson at the Southern Association for Vascular Surgery (one of the oldest vascular meetings) and Dr. Rassmussen and Dr. Gifford received nothing but praise.
Life away from the lab - relaxing and having fun
Also, Dr. Gifford has brushed up on his golf game a bit. He still needs some practice and hopes to work out a good schedule next year to get in a few holes a week...or not.
Dr. Gifford says that the non-scientific rewards of his research experience has been to be a good dad and husband with the extra time he's had available to spend with his family, i.e., being normal again. Dr. Gifford feels that residency is great and there are so many interesting things happening. That being said, the residency years are hard on a family because of the enormous time commitment. Taking a break, slowing down, and doing the normal family thing was the best.
Dr. Gifford started his residency not interested in research and
planning to plug right through it. Due to some special
circumstances with his son, he needed to take some time with his family,
and decided to roll the family's needs into the research time.
According to him, it was the best decision he ever made — maybe it
couldn't be called 'interesting', but for Dr. Gifford and his family, it has
definitely been rewarding.
Richard Oppeltz, MD
Jason Wells, MD
Heather Hancock, MD
2009 Summer Research Medical Students:
The Office of the Medical Dean provides funds to support medical students engaged in research projects with UTHSCSA faculty during the summer break after the first year. Summer stipends are awarded for 5-8 weeks of full-time research. Congratulations to the three UT School of Medicine students who will be participating in Surgery research projects this summer:
Medical student: Jennifer Sasaki
Medical student: Tyler Bloomer
Medical student: Erin Wait
Medical student: Taylor Dunphy
As a diversion from the rigors of medicine and research, Vice Chair for Research Steve Wolf, MD, has instituted a monthly book club for the residents in research. On approximately a monthly basis a book is assigned for reading which is then discussed as a group. Beyond the reading, the gathering allows both the faculty and residents to interact in an informal capacity and on equal footing, since no one is an "expert". The following books have been read and discussed over the past few months:
Freakonomics: A Rogue Economist Explores the Hidden Side of Everything
This 2005 non-fiction book by University of Chicago economist Steven Levitt and New York Times journalist Stephen J. Dubner has been described as melding pop culture with economics. As of 2008, it had sold over 3 million copies worldwide. (Wikipedia)
Angela's Ashes is a memoir by Irish author Frank McCourt, and tells the story of his childhood in Brooklyn and Ireland. It was published in 1996 and won the Pulitzer Prize for Biography or Autobiography. (Wikipedia)
Daniel Dent, MD, General and Laparoendoscopic Surgery - January 2009:
NIGMS Subgrant with University of Virginia ($30,000), SIS multicenter study of duration for intraabdominal infection.
Miguel Fernandez, MD, Medical Director, The South Texas Poison Center, Division of Emergency Medicine - December 2008:
Texas Department of Health ($149,057), EPI-Poison Control Centers.
Kent Van Sickle, MD, General and Laparoendoscopic Surgery - April 2009:
U.S. Surgical ($70,000), U.S. Surgical Fellowship Agreement 2009-2010.
Joshua Walker, CCO, Perfusionist, Cardiothoracic Surgery - February 2009:
NIH Subaward with Transonic, Inc. ($14,976), Validating the Calculation of Mixed Venous Saturation While on Veno-Venous ECMO.
Steven Wolf, MD, Vice Chair for Surgery Research, Division of Trauma and Emergency Surgery - May 2009:
Elizabeth Huth Coates Maddux Foundation ($100,000), Fellowship Program for a resident in Surgery/Regenerative Medicine.
July 10-12, 2008, San Francisco, CA
Aug 26-29, 2009, State College, PA
Aug 31-Sept 2, 2009, San Antonio, TX
Sept 3-5, 2009, San Francisco, CA
Sept 6-10, 2009, Adelaide, Australia
Sept 9-12, 2009, Boston, MA
Sept 30-Oct 3, 2009, Orlando, FL
If you have a meeting or event you would like listed, please let us know so that it can be included in the next issue.
© 2009 The University of Texas Health Science Center at San Antonio Department of Surgery. All rights reserved. Contact us. Volume 4, Issue 2, June 2009.
For more information on any of these articles, please email the Research News editor.