July 2008 Archives

The Heart of the Matter

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Recent studies have found that the critical role played by mitochondria in cardiac cells lies at the heart of “myocardial preconditioning�. This term refers to the period of brief ischemia and reperfusion via revascularization and oxygenation of the heart that primes the mitochondria into a stress-resistant state so that prolonged periods of ischemia in the future are much more tolerable. Effective priming results in reduced risk for cardiac infarctions and reduced rates of cardiac cell death, perhaps because the mitochondria have acquired a protective phenotype in the ischemic area. Additionally, studies have suggested that generation of ROS or Reactive Oxygen Species may play a part in signaling cardiac cells in ischemic regions of the heart to undergo apoptosis or programmed cell death rather than necrosis, and in doing so, allow for partial or even full recovery of cardiac tissue. While conducting research with my mentor at the VA Medical Center over the past year, I found a significant decrease in generation of ROS in primary cardiac swine cells under hypoxic conditions (5% oxygen) as opposed to normoxic conditions (21% oxygen), results I had the opportunity to present at the Undergraduate Research Symposium this past spring. These conditions mimic in vitro what occurs in vivo in an ischemic heart, implying that ROS may act as a signaler or downstream regulator of a signaler in inducing the myocardium to hibernate.
In a similar experiment conducted by Vanden, T. et al., chick embryonic ventricular myocytes were exposed to hydrogen peroxide, a type of ROS, to mimic the effects of inducing hypoxic preconditioning. The researchers found a significantly lower level of cell death for these myocytes when hypoxia and reoxygenation were induced in the future.
Even more interesting, recent research concerning myocardial hibernation conducted by Levy R. et al. has shown its association with the septic heart. Sepsis, a systemic illness caused by bacteria and toxins and resulting in multi-organ failure, is the leading cause of death for critically ill patients in the U.S, making the hibernating model even more important. The study found that the changes seen during myocardial hibernation occur in the septic heart, and that during sepsis, cardiomyocytes (heart muscle cells) become “functionally hypoxic� even though plenty of oxygen is available and no ischemia occurs. So what appears to be multiple organ failure might actually be multiple organ hibernation, and play an adaptive or protective role.
I find this research fascinating and highly applicable to cardiac care as well as my future career area of interest, cardiothoracic surgery. Over the last few weeks, I’ve been working on ring studies with my mentor. The LAD or left anterior descending artery (the site of constrictor placement to induce ischemia) and circumflex were isolated from revascularized pig hearts, and vascular constriction was measured at resting conditions and stressed conditions with the addition of ET-1, a well-established vasoconstrictor. What we’re seeing is amazing and difficult to interpret. In the coming weeks, I’m hoping to try to get a handle on how to analyze iTRAC data and proteomics in order to begin to get an understanding of what we’re observing – should be exciting!

Old memories, new experiences

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It’s hard to believe that freshman year has already flown by. I finished last semester with a much better handle on Organic Chemistry, a subject I once considered to be nightmarish, but has actually turned out to be enjoyable and surprisingly interesting. It’s fascinating how taking the time to preview chapters before class and working review problems really do help with learning new material. And along with acquiring drastically improved time management skills, wonderful memories shared with other students and faculty, a deeper understanding of my capabilities and weaknesses, I’ve also gained a better idea of how I want to spend the remaining three years of my CBS experience.

Summer is now in full swing and the new school year is fast approaching. However, I’ve already had a few fun experiences that have turned out to be quite meaningful. A few weeks ago, I got the chance to visit Shanghai, China for a couple of weeks to visit family and travel. Besides gorging myself on a variety of delicious foods at a near hourly rate, spending way too much time shopping and sightseeing, and visiting some cool historical sights, I also spent a day at the main thoracic hospital in Shanghai. My uncle, the director of the thoracic surgery department there, was willing to let me shadow him as he spent the day performing lung surgeries and observing his residents. The learning experience that followed provided me with a valuable glimpse into medicine performed under a health care system very different from the one here.

Upon entering the hospital, the first thing I noticed was the sheer number of people -everywhere. Practically all the seats in the waiting areas were occupied, and on every floor, I could see dozens of smokers. This seemed very ironic to me, since it is a pulmonary hospital that specializes in thoracic cases and lung cancers. I was very tempted to explain to these individuals the error in their ways, but my uncle cautioned that in China, smoking is so ingrained in the cultural identity of a large portion of the public that it will likely take years before the behavior can be lessened to any extent. As my uncle and his residents checked up on their patients during morning rounds, I was free to wander the halls a bit and take in the sights of the hospital. Nurses were dressed in crisp and spotless white gowns (the kind seen in old movies), and doctors wore their signature white coats over formal business attire at all times. What struck me as very odd was the virtual nonexistence of doctor-patient confidentiality. No dividers were present within patient rooms, and I often saw doctors discussing matters with patients and their families or performing brief examinations while other patients were still in the room. But, I guess that’s about as private as it can get in a hospital that serves so many people.

However, the twelve operating rooms in the hospital, I found, were very similar in setup to ones I have been in before, boasting the newest technology and the most advanced surgical techniques like laparoscopy. Sterile instruments were set up neatly by the carefully draped patient. Even the same brand of scrub-in soap was used for each procedure. I watched in awe as my uncle performed lung biopsies to identify suspicious masses in the lung, and perform pneumonectomies and lobectomies. I even got to see his “patented� method of removing lung tissue. Using laparoscopy, he inserted a sterile glove through a tiny incision into the thoracic cavity, placed the lung tissue into the glove by viewing the monitor, and dragged the glove out of the incision. After a day of observation of both my uncle’s procedures and those of his peers, I realized that no matter the culture or the health system, attention to detail and to quality patient care remain the most critical components of effective medical care. Returning to the United States, I brought back with me an appreciation for the rich cultural history and traditions of China, and amazement at the remarkable pace of advancement of a China that is continuing to develop and prosper.

About Katie

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Katie Bressler I am a CBS sophomore still figuring out what exactly I want to do with the rest of my life. To help gain some perspective, I have decided to participate in the Learning Abroad Center’s MSID Ecuador program, where I will be studying and interning with a nonprofit organization related to health care from August through May. Back at the U, I am participating in the Community Engagement Scholars Program, and I am enrolled in the Dual Degree Program between CBS and CLA. My intended majors are Microbiology and Spanish Studies. Someday I hope to be in a helping profession, possibly health care.

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This page is an archive of entries from July 2008 listed from newest to oldest.

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