Sabine Vogler  

Home Institution
Charité Universitätsmedizin Berlin, Campus Benjamin Franklin,
Center for Space Medicine Berlin (ZWMB),
Department of Physiology, Berlin

Host Institution(s)
University of California at San Diego,
UCSD Medical Center, Department of Orthopeadic Surgery
Mentor: Alan R. Hargens. Ph.D.

E-Mail: sabinevogler@gmx.de
Research Topic
see Abstract
Personal Reactions to the U.S. Experience
Not for nothing, San Diego is called as America’s finest city! I had a wonderful time in San Diego! My stay in California was very exciting for me, as this was my very first time being in the US. I can truly say that California will be an unforgettable experience for me.
There is a big mixture of cultures living in California, making life in there very interesting, especially in San Diego. There are also many varieties of landscapes in California: you have beaches, mountains and desert. From San Diego you can also easily drive to Mexico, Los Angeles or Las Vegas. I met a lot of very kind and interesting people. And, I had, besides, really great research opportunities, and a lot of fun with the people in my lab.
Greatest Difficulties Encountered
As I entered the US, I learned quickly that you can do nothing in this country without your Social Security number, so get that done in the very first days!
Most humorous incident
I had quite a few humorous incidents, mostly situation related.
As one of the former BMEP-stipend recipients has already mentioned, never forget you ID if you go to a bar or restaurant in California! I was with my lab colleagues at a brewery, and the waitress asked me for my ID. I was lucky, I thought, because I carried my passport with me, but she didn’t want to accept this. So, after I showed her my credit/debit cards, my isac, my German driver’s licence, and whatever else I found in my wallet, we finally figured out that she wanted to see the bio-descriptions on an ID. Well, I could show her a page in my passport, in German certainly, and she finally accepted it. This whole situation was afterwards quite funny, at least for the people around me! It seemed to be actually easier to get into the US than to get a beer there. Try to get a Californian driver’s licence, or the non-drivers ID ASAP, since this makes life here much easier!
Helpful Hints for Future Students
  • San Diego Reader, www.sdreader.com, has a lot of news about housing, best locations and events in San Diego. Also, check out: http://sandiego.craigslist.org/
  • Besides your German bank account by Deutsche Bank or Citibank, try to get an additional American account, as you have to pay fees if you want to pay with your German credit and debit cards in local stores.
  • Try to buy a car, as the transportations system is not very good in San Diego.
  • If you want to drive your own car in California, you have to get the Californian driver’s licence, which is just $26 but you have to take both a written and a driving test.
  • If you get the chance to stay in San Diego, don’t hesitate to contact me!

Sabine Vogler, who spent her AY 2005-2006 in the U.S. at the University of California San Diego Medical Center, was married to Matthias Meuche while on a vacation trip to Hawaii. Matthias is a German whom Sabine has known for five years. He came to visit her in the States for one month, and they had a short holiday for a week at Maui, where they were married. While she is still in the United States, she will continue to use her maiden name, but plans to do the paperwork in Germany in order to use the name Sabine Meuche.

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Abstract on Research Topic
WISE-2005: The relation between balance and orthostatic tolerance in women
Institution:
Orthopaedic Surgery, University of California, San Diego, 350 Dickinson Street, Suite 121, San Diego, CA, 92103-8894

Authors:
Sabine Vogler, Wanda Boda, Suzanne M. Schneider, Brandon R. Macias, Rachel B. Tullet, Stuart M.C. Lee, Patrick Guinet, Alan R. Hargens

Introduction:
Balance control is dependent upon feedback from the proprioceptive, visual and vestibular systems.1,2 Animal studies have shown that vestibular stimulation can effect orthostatic tolerance.3 Post- spaceflight orthostatic intolerance might be related to changes in vestibular system after exposure to micro-gravity.4 Loss of visual feedback may increase the importance of vestibular system in balance control5, therefore standing balance tests with eyes closed (SBC) should be a good method to examine the relationship between the vestibular system and orthostatic tolerance.

Methods:
Subjects. 24 female subjects (32±4 yrs; 59±5 kg; 166±6,8 cm; mean±SD) participated in this 60-d 6°-HDT bed-rest study after giving their informed, written consent.

Experimental design:
During BR, eight healthy women performed aerobic exercise LBNPex and resistive exercise Rex on separate days, while eight matched, control subjects performed no exercise (CON). The supine LBNPex countermeasure employed an intermittent (40-80% pre-BR VO2pk), 40-min protocol within LBNP (-49±3 mmHg) applied to provide a footward force equivalent to 1.0-1.2 body weight (BW) and followed by 10 min of resting LBNP at approx 1.0 BW. Rex consisted of maximal concentric and eccentric supine leg press and heel raise exercises using a gravity-independent flywheel ergometer. Another group of 8 women received a daily additional protein intake of 30 to 40g (NUT), no exercise countermeasures were performed.

Test protocol:
Subjects performed balance tests consisting of standing on one foot on the width of a balance beam (4,96m long, 0,1m wide) with eyes open (SBO) and closed (SBC) for up to 30sec.
Based on their pre bed rest SBC- test results, all subjects independent of their intervention status as CON, EX or NUT were classified as Finishers (F-SBC), if they could finish the 30sec of the SBC-test or Non –finishers (NF-SBC) if they did not complete the test.
Orthostatic tolerance (OT) was measured during a tilt/LBNP test consisting of tilting the subjects 70° head up for 10 min and then applying LBNP in 10 mmHg stages every 3 min until the onset of pre-syncopal symptoms (total time in sec). Pre-syncope was defined as a sudden fall in blood pressure (>25 mmHg) or drop in heart rate (>15 bpm), severe symptoms or systolic blood pressure under 70 mmHg.
Balance data and orthostatic tolerance-times were collected 4 days before bed-rest period (PRE), and directly after getting up (POST).

Statistical analyses:
Values are expressed as mean±SD. OT-times for F-SBC and NF-SBC were compared using a Mann-Whitney U-test. Statistical significance level was set at p<0.05.

Results:
Pre bed rest, all subjects could finish SBO-test, 15 subjects could finish the SBC-test (F-SBC), 9 subjects could not finish the SBC-test (NF-SBC) pre bed rest. Significantly longer OT-times can be observed in F-SBC than in NF- SBC (p=0.018), pre bed rest.
Post bed rest, balance time and OT-time was significantly less post bed rest compared to pre bed rest in both F-SBC and NF-SBC- groups (p<0.05).
Balance time (p=0.01) and OT-time (p=0.027) was significantly longer in F-SBC compared to NF-SBC, post bed rest.

Discusssion:
Longer balance time without visual inputs seems to be related to greater orthostatic tolerance in these subjects but the pathways involved are unknown.
Balance ability may be an indicator of the vestibular systems functional capacity.
Vestibular system is known to participate in the autonomic and cardiovascular regulation.6 And, orthostatic tolerance might depend upon inputs from the vestibular system by adjusting blood pressure and vascular resistance.7, 8
SBC-tests indicate the vestibular systems functional capacity, and based on these data SBC-tests may also predict orthostatic tolerance capacity.

Conclusion:
Subjects who had greater standing balance time with eyes closed showed higher orthostatic tolerance. Visual input may compensate for a lower orthostatic tolerance capacity.
The mechanism by which orthostatic tolerance is related to balance ability and vestibular system is not understood. Further development of the potential of SBC-tests in predicting orthostatic intolerance e.g. following spaceflight may be beneficial.

References:
1. Horak FB et al. Exp.Brain Res.1990;82(1):167-77
2. Horak FB et al. Adv Exp Med Biol.2002;508:139-45
3. Jian BJ et al. J Appl Physiol.1999;88(5):1552-1560
4. Yates BJ, Kerman IA. Brain Res Brain Res Rev.1998 Nov; 28(1-2):73-82
5. Brandt et al. Disorders of posture and gait.1986:157-175
6. Yates BJ et al. Brain Res Bull.2000 Sep;53(1):3-9
7. Monahan KD, Ray CA. Am J Physiol Regul Integr Comp Physiol.2000; 283:R1027-32
8. Ray C. Am J Physiol Heart Circ Physiol 2000; 279:H2399-2404