Jonas Jae-Hyun Park

Home Institution
University of Hamburg

Host Institution
Department of Surgery, Columbia University, New York City
Research Mentors: Michal Bereta, Howard Kaufman

E-Mail: jjh.park@web.de

Research Topic
see Abstract
Personal Reactions to the U.S. Experience
NYC? - rough'n tough! The outward appearance of the city contributes much to it. Among the cities I have visited or lived in, NYC counts as one of the dirtiest. Garbage bags are piled up at street-side, waiting to get picked up. The greatest number of rats I have seen together at once must have been around six or so.
NYC? - rough'n tough! How hard people without money are hit in a society with high living standards! NYC shows it in a most unveiled way, compared with other cities in western countries. If I gave a dollar to everyone who begged me for money, my purse would be seriously injured. This is a city where you pay a minimum of $250 monthly for your own parking spot in downtown Manhattan. On the subway, next to normal, decent and beautiful looking people, you will find people who would be admitted to the hospital because of severe mental disorders in Germany, people on drugs, and homeless people sleeping and emitting strong odors. This is the daily scene, while everyone on the train is wrapped up in his own thoughts.
NYC? - rough'n tough! People here are not restrained to say or do immediately whatever they think and feel - and do it loudly. On the other hand, it is easy to get in contact with people, since they are very outgoing.
NYC? - rough'n tough! Every ethnic group seems to demand their right to come to this city to make money. This city seems (but just seems) to be the center of the world. Maybe this is one of the differences compared with other 'international' cities like Berlin or Paris. Everything is dense in NYC - you can walk one or two blocks farther and you are really somewhere else.
Greatest Difficulties Encountered
Bureaucracy! It is February and I have not received my Social Security number yet! At least things work in good old Deutschland! Here in NYC, you can apply or send a request, but there is no guarantee for anything. As it is written many times, finding a suitable place to stay is not easy. There are definitely cheap ($400/month) offers to find. But you don't want to live with someone who sleeps in the kitchen with three dogs, and especially not when there is no way, other than getting through this kitchen, to reach your room. After one and a half months in Harlem, where I had to pay for a damaged floor, ruined by a couple of ink spots, which could have easily been wiped off with detergent, and where I was given a chance to listen to the sound of three gun shots, I moved to Queens for a month, and finally settled in Brooklyn, in a very neat neighborhood.
Most humorous incident
I don't know whether one should laugh because it is funny or sad to hear, "It's the law," or "We have to follow the rules."
Helpful Hints for Future Students
I hope I did not scare anyone away from NYC. I thought I would write something different than how cool or 'great' NYC is. Maybe I am disillusioned a bit by this city, compared with its image, as it is created by the media abroad. In fact, NYC is much hipper, more energetic, more diverse and more of a 'trendsetter' than people would think. You don't recognize this at the first sight, and especially not as a tourist. But after you sink into its life … So if you ask me about NYC: NYC? - I love NYC! Seriously, I think the most helpful hint for students trying to come to NYC would be to contact people who have been in NYC. You will be working a lot. But this won't be different anywhere else.

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Abstract on Research Topic
Optimization of the vaccination protocol for prevention of tumor progression in Apc/CEA mice

Authors
Michal Bereta, Jonas Jae-Hyun Park, Howard Kaufman

Institution
Department of Surgery, Columbia University
Purpose
To optimize vaccination protocol for prevention of colorectal cancer
Materials and Methods
Apc/CEA mice, cDNA-CEA, rVV-CEA, Celllines EL4, EL4CEA, Wallack Scintilation Counter, FACS Calibur, GraphPad Prism 3.0
Assays
ELISA for CEA and IFN-?, Chromium releasing assay for measuring cytotoxic activity, 3H-thymidine proliferation assay, Flow cytometric analysis using COL-1 mAb and FITC-labeled goat-anti mouse Ig (Fab2) for detecting CEA on the surface of EL4CEA cells used as a target in the chromium releasing assay, PCR for identification of Apc/CEA transgenic animals
Results
Apc/CEA mice at the age of 2-4 months were vaccinated 3 times at biweekly intervals. To diversify vaccination regiment we used cDNA-CEA (10 ug/dose) injected intradermally for priming immune responses, followed by s.c. injection of rVV-CEA and finally systemic (i.v. or i.r.) injection of rVV-CEA at 10(7)/dose. At the age of 8 months mice were sacrificed by cervical dislocation, the whole digestive system was isolated and prepared for histological examination. Serum and splenocytes were collected for in vitro assays.
Boosting with rVV-CEA stimulated potent humoral responses (anti-CEA ab titers >1:128 000) and a 5-10-fold stimulation of splenocytes proliferation which was measured in in vitro assays by incorporation of 3H-thymidine. Anti-CEA CTL activity was generally weaker and for the detection of CTLs splenocytes were cultured for 7 days in the presence of gamma-irradiated tumor cells. CTL activity of splenocytes obtained from vaccinated animals was up to 40% of CEA-specific lysis at a 200:1 effector to target ratio.
These data indicate that vaccination according to our protocol stimulates humoral as well as cellular immune responses that efficiently protect mice from tumor progression. This was evaluated by histological examination that revealed not only smaller number of polyps in G.I. tract but also less advanced stages of tumor progression in detected polyps. Although both routs of the final boost delivery (i.v. and i.r.) seem to be suitable for effective vaccination, i.r. delivery of the vaccine seems to be superior over i.v. injection due to more localized and thus less harmful site effects of the vaccination.
Conclusion
We found that priming of immune responses with cDNA-CEA followed by two consecutive boost vaccinations with rVV-CEA is a very effective method of preventing progression of colon adenocarcinomas in Apc/CEA mice. We did not observe any adverse effects of the vaccine in our experimental model. Long term survival studies that should confirm the benefit of our protocol of preventive vaccination are being currently conducted.