Matthias Meier

Home Institution
Johannes Gutenberg Universität Mainz

Host Institution(s)
Cardiothoracic Surgery, Mount Sinai School of Medicine, New York City
Research Mentor: Randall B. Griepp, M.D.

E-Mail:
 matsiesurfs@compuserve.de

Research Topic
see Abstract
Personal Reactions to the U.S. Experience
Prior to my stay here in New York, I had lived 4 years in Dallas,Texas, so at least the language was no obstacle. To no great surprise though, New York City is not comparable to Dallas. There are people everywhere at every time of day and night. Everything is always moving, and there are always things happening. One thing that struck me was the extent to which one is controlled. Cameras in the elevators, bag searches when entering the hospitals (or museums for that fact) and security officers always checking your ID were daily experiences. The shadow of September 11th still hovers over New York, and this is the way it is manifested. New York is very international, and many different languages can be heard walking down the streets. All in all I think New York City is the most diverse place one could possibly live in, which makes it very interesting.
Greatest Difficulties Encountered
When I arrived in New York I realized with horror that my German EC Card didn't work in the US, although my bank had assured me it would. So I had a hard time for a couple of days, and I was envisioning myself living on the streets in no time, because of failure to pay the rent. Gladly things resolved quickly through the help of lab colleges. Then the only great difficulty left was the experimental work in the lab. Almost everything possible went wrong, and for the first 2 ½ months we struggled quite a bit. One other thing that bothered me as well is that I couldn't find a place to swim in Manhattan without paying monstrous sums of money. The price of the square meter is so high that a swimming pool wouldn't pay off without high prices, so there are lots of sports clubs which offer a great variety of sports, but to a price unaffordable to me.
Most humorous incident
So many funny things happened, it's hard to pick one. So I'll pick two:
In the lab we performed cardiac surgery on pigs, which were video taped for 7 days postoperatively at 7am every morning. To do this we had to transport the pigs in a small transporter cage from their "home cage" to a room called "the maze", which was essentially a maze, where they were fed apple pieces, and their motor function was assessed. When trying to pursuade the pigs to get into or out of the transporter cage, there was always the slight danger of them jumping out and running around frightened and uncontrolled. Well, one pig did just that and crept underneath three big cages that were on wheels and had a space underneath of about 20cm, crawling around looking like a navy seal on a secret mission.
The other incident was on New Year's Eve. I was in a bar with some friends with live music. At 11:30 p.m. Chris Barren (singer and lead guitarist of the Spin Doctors) started his show. Afterwards my already a bit drunken girl friend asked for an autograph and took my New York guide for him to sign. He had been humorously covering Eminem and wrote "I never meant to hurt you, I never meant to make you cry, Chris Barren" into my NY guide.

Helpful Hints for Future Students

  • Get an idea of the city before you go, it will help you decide how much money to take and what to arrange (i.e. car, apartment, subway prices…)
  • Ask BMEP students that went to the same city as you. Other cities = other experiences.
  • Be nice to everyone in the lab you work in, it almost always pays off.

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Abstract on Research Topic
Selective Cerebral Perfusion (SCP) with alpha stat and ph-stat after cardio-pulmonary bypass in a pig model
Note: This is only one of the studies we engaged in. The others include a blood pressure SCP study and a spinal cord ischemia study).
Authors:
James Halstead, Matthias Meier, Ning Zhang, Carol Bodian, Don Weisz, David Spielvogel, Randall B. Griepp
Institution:
Cardiothoracic Surgery, Mount Sinai School of Medicine, New York, New York
Purpose:
When operating on aneurysms of the aortic arch the supraaortic branches are sewn to a graft proximal of the arch, which is then clamped distally thus perfusing only the supraaortic branches ("Selective Cerebral Perfusion" = SCP). The body is cooled to a certain temperature to ensure a degree of neuroprotection. There are two different strategies for pH-control. Either the pH is maintained throughout cooling at approximately 7.40 (alpha-Stat), or it is lowered according to temperature, which is the actual physiological method (pH-Stat). When performing pH-Stat, carbondioxide is administered, this has a vasodilatative effect, which increases blood flow to the brain but also the embolic load. To examine these two different strategies is the purpose of our study.
Materials and Methods:
A pig from the Yorkshire strain weighing 25-30 kilograms is anesthetized with 1.5% isoflurane. It is washed and draped in a sterile fashion. The sagital sinus is cannulated for extracting venous blood gas samples, and electrodes are placed on the dura mater to enable Visual Evoked Potentials (VEPs) to be analyzed. Then the axillary artery is dissected and canulated to demonstrate the arterial blood pressure and to extract arterial blood samples. A lateral thoracotomy is performed and the pericardium opened. The pig is then prepared for cardio-pulmonary bypass, which is followed by a cooling period of 30 minutes in which the pig reaches a body temperature of 20 degrees Celsius. At different time points in the operation microspheres are administered, with different colors representing different time points, into the left atrium whilst blood is withdrawn from the axillary artery for blood flow analyses. The ascending and descending aorta are cross-clamped and SCP is initiated. This lasts for 90 minutes, after which the pig is rewarmed. At approximately 28 degrees Celsius the heart is defibrillated, and rewarming is continued until 36,5 degrees Celsius. Then cardio-pulmonary bypass is discontinued and the chest is closed.
The pigs are video monitored for seven days postoperatively to assess appetite, motor functions and alertness. After seven days the animals are sacrificed and the brain is removed, and tissue samples are prepared so as to isolate the microspheres whose density, in turn, are measured in a photometer to calculate blood flow at different times of the operation.
Results:
In pH-Stat animals it is seen that blood flow during SCP is higher, which is to be expected. The outcome in terms of behavioral score shows no benefit of pH-stat. Final results are pending. Conclusion: As the pigs are healthy and not arteriosclerotic a higher blood flow than alpha stat shows no benefits. The embolic load is higher in the pH-stat group, although no significant difference in the neurobehavioral score can be ascertained.