Ortrud Kosiek

Home Institution
Christian-Albrechts-Universität Kiel

Host Institution(s)
Department of Surgery and Cellular and Molecular Physiology, Yale University School of Medicine
Mentors: John P. Geibel, M.D., Ph.D.

E-Mail:
 okosiek@web.de

Research Topic
see Abstract
Personal Reactions to the U.S. Experience
Asked to describe my stay in the U.S. in one short sentence, there can be just one possible answer for me: I had the most wonderful time.
This was not the first extended stay in the U.S. for me, however the first time of being in New England, and this made me realize what an immensely large country the U.S is indeed, and that it makes a tremendous difference in which part you are. But of course, there are a lot of universal American features, and I just want to pick out a couple here, that I think are worth mentioning for me for various reasons. The U.S. is definitely a country with incredible opportunities and freedom, which makes it much harder in consequence to understand why there are such ridiculous regulations. For example on when and where to buy alcohol, as well as where and how to drink it, but at the same time you can feel as free as you like to waste everything, may that be food, energy or whatever else. Just to see how many plastic bags everybody takes home from the grocery store can make you feel sick!
As much as there had been concerns prior to coming here regarding the tensions between the U.S. and Germany on the governmental level, I fortunately very soon was able to find out that there are a lot of people who do not share the views that their governments propagate and which appear in the media according to that. In this context I really have to mention that Yale in particular offers outstanding opportunities besides the medical research field, to become informed, involved and take part in such activities as politics, and I feel especially grateful that I was given the chance to experience that.
Greatest Difficulties Encountered
I can't really say that I met great difficulties, at least none where there was not a solution to it. Talking to a lot of people usually helped tremendously whenever there was a problem coming up. For me the most unpleasant part of it was definitely before I even got on the plane, when I was looking for a place to stay. That really did cost me a lot of sleepless hours at night.
Most humorous incident
Flying into New York La Guardia Airport one day, and having passed the baggage claim, I wanted to make my way home to New Haven, which is about a 1-hour ride by car (or alternatively you can go via public transport by bus and then take the train.) But as I had a very long day of travel, I wanted to get there as quickly as possible and also rather comfortably, so I decided to take the so-called Connecticut Limo service which is a mini van service for a still somewhat affordable price ($42). But what you find there at the airport is already a line of taxi drivers who pretty aggressively offer their services and also almost instantly grab your suitcase. One guy asked me where I needed to go, so I told him that I was looking for the service to New Haven. Of course, he said: No problem. The question how much that would cost, he said he had to look into his book in his car first, he even couldn't tell just about how much it would be approximately. I told him that about $50 was all I could afford. Again: No Problem. Walking to his cab I slowly started to get the impression, that he was not quite knowing where I wanted to go at all, but at that point I just followed him out of curiosity. Well, in the end, after turning a lot of pages over and over again in his book, he found it: $322. Understandably, I had to turn down his last, very kind offer of only charging me $250 dollars as well!

Helpful Hints for Future Students

  • If possible get in contact with the people who work in the lab that you are going to join in advance and try to find out as much about the working conditions as possible. That may help to prevent negative surprises.
  • Whenever you use a debit card to pay for something you want to purchase at a store, make sure that you actually did pay for it when you leave the store, especially when the nice sales clerk wants to talk you into getting some sort of special bonus point system thing. That happened to me and believing that everything was okay, I took off for Christmas, and happened to get a bill in the mail which was already past the due day when I got back from my trip. So it was some kind of an effort to not having to pay an extra $25 fee for that!
  • Most important: enjoy every day!

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Abstract on Research Topic
Chloride influx in rat Gastric parietal cells is Na+/K+/2Cl- cotransporter (NKCC) dependent
Authors:
O. Kosiek, E. Vucic, JP Geibel
Institution:
Department of Surgery and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT
Introduction:
The chloride influx necessary for gastric acid secretion was thought to occur via stimulation of a basolateral Cl/HCO3 exchanger. Recently there has been direct evidence for NKCC protein on the basolateral membrane of parietal cells, the exact role of this protein remains controversial to date. The aim of the present study was to investigate the role of NKCC in stimulated gastric parietal cells and determine if this protein could function as the chloride influx pathway.
Materials and Methods:
Individual hand dissected gastric glands from rat stomach were loaded with the chloride sensitive dye MQAE for intracellular Cl measurements using a digital imaging system. During dye loading individual glands were pre-incubated with histamine to induce acid secretion. To observe NKCC dependent Cl influx, gastric glands were perfused with various ion substituted buffer solutions: 1.) 0Cl, 0Na HEPES/NMDG buffer (to deplete the parietal cell of intracellular chloride in the absence of extracellular Na). 2.) 0Na HEPES/NMDG buffer ( to observe Cl loading of the parietal cells in the absence of Na) 3.) HEPES Ringer ( to observe Na dependent Cl uptake). In a separate series glands were exposed to buffers that contained NPPB to prevent Cl channel activity. All studies were conducted in the absence of HCO3 to eliminate Cl/HCO3 exchanger activity. A control series in the absence of histamine was also performed. Results: 1.) The Cl loading of gastric parietal cells is Na dependent. The addition of Cl to the bath in the absence of Na and in the presence of NPPB prevents Cl entry into the parietal cells. 2.) A Na and Cl containing Ringer solution caused rapid increase in intracellular Cl.

Conclusion:
We conclude from the present study, that the recently identified basolateral membrane NKCC protein is the predominant Cl influx pathway following histamine stimulation in rat parietal cells. Histamine has been shown to increase cAMP levels in the parietal cell, elevations in cAMP also lead to increases in NKCC activity and therefore provide further evidence that this protein may be the predominant Cl influx pathway during secretagogues induced acid secretion.