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| Nikolaus
Trautmann |
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Home
Institution
Albert-Ludwigs-Universität Freiburg
Host
Institution
University
of California, San Francisco
Mentor: Matthew M. La Vail
E-Mail
picknick@bigfoot.de
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Research
Topic
see Abstract |
Personal
Reactions to the U.S. Experience
To be honest, for various reasons, the United States overall is not my favorite
country. But…wow! San Francisco is certainly one of the best places to be
in the world. The city is great, interesting, freaked-out and absolutely
not typically American. The climate is perfect, not too hot, not too cold
(if you can live with the fog), and California offers everything from mountains
for skiing and hiking, to the ocean for surfing. I've started rock-climbing
and mountain-biking, among other things, which I always wanted to do, but
never found the time for before. Traveling is another nice aspect. I've
visited many other BMEP students and friends in very different parts of
the United States. |
Greatest
Difficulties Encountered
Finding social contacts was a lot tougher than I had expected. The people
in my lab were all great but not of the sort to go out at night. My first
roommate was terribly boring and most Americans I met were very busy with
their existing friends and hobbies. UCSF is a small university without undergraduates,
and there aren't many other exchange students either, so it was hard in
the beginning. However, after a little while things were much better. |
Most
humorous incident
After returning to San Francisco, after Christmas, Roman and I went to a
bar, and I showed him the new 20 Euro bill. The bartender got interested
and wanted to have a look, too. Soon my bill was passed around the whole
bar, and people were discussing the safety features and comparing it with
a $20 bill. Just before we left, a guy approached me and asked if I could
show him some new EURO coins, too. It was very amusing. |
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Helpful
Hints for Future Students
- Come to San Francisco. Seriously: picking a great location can make
up for eventual bad luck in the lab.
- Get yourself a Social Security card as soon as possible. A local driver's
license can also be a very valuable thing. Be prepared for terrible bureaucracy
everywhere.
- Life is expensive in the US, and especially in San Francisco. But usually
it's possible to get financial support from your lab here; don't be afraid
to ask.
- Get a bank account at Bank of America; it is a member of the German
cash group. I had an account at the Deutsche Bank and could withdraw cash
for free. However I heard with Commerzbank it doesn't work as well.
-
Explore a number of different labs before choosing. Try to communicate
as well as possible with your new lab group and be clear about your and
their objectives, and your projects in the lab. Bigger labs may offer
more contacts and more methods to learn, but smaller ones (like mine)
may have a more personal atmosphere.
- Be open to the American culture. Don't try to continue your life the
way you used to have it. Try watching American football, eating American
food, going to parties that start at 5 p.m. or small-talking all day.
You'll get back to your old lifestyle soon enough.
- Consider taking two semesters off, it may be worth it.
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September
11
Fear. Anger. Nausea. Frustration. Confusion. Disbelief. Grief. Detachment.
Numbness. Sorrow. Loss. Surrealism. Denial. Exhaustion. Ambiguity. Apathy.
Idealism. Cynicism. Loss of control. Disconnection. Victimization. Hypocrisy.
-- The space here is insufficient to elaborate my thoughts and feeling after
the terrorist attacks, but, to cut it short, it was tough to be in Boston
when it happened, but tougher to be in the United States during the post-9/11
events. |
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Abstract
on Research Topic:
Rhodopsin levels in eight rodent models for retinal degeneration |
Authors:
N. Trautmann, M. La Vail |
Institution
at which research was done:
Department of Ophthalmology, University of California, San Francisco. |
Purpose:
Photoreceptor degeneration is the cause of blindness in diseases like retinitis
pigmentosa, which affects 1 in 3500 people worldwide and age-related macular
degeneration, which affects vision in the elderly in as many as 1:3 by the
age of 75. Several rodent models have been established to study new treatments
for these diseases.
The MER protein plays a crucial role in phagocytotis of apoptotic cells.
Mice with a mutation in the kinase domain of the Mer gene, show, besides
an immune deficit, a form of photoreceptor degeneration. Due to the inability
of the RPE (retinal pigment epithelium) to phagocytose discs of rod outer
segments, they form a debris zone in the outer retina, which causes photoreceptor
cell death. P23H and S334ter are two common mutations in the rhodopsin protein
responsible for retinitis pigmentosa that can now be studied in a rat model.
Seven different lines of transgenic animals are currently being characterized
to serve as models for human retinal degeneration. Besides functional studies
with ERG (electroretinogramm) and structural analysis, the levels of rhodopsin
in the eyes of these animals will offer another parameter to characterize
degeneration and measure the success of future therapies. |
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Materials
and Methods:
Animals were dark-adapted overnight and all procedures performed in dim
red light. Both eyes from each dark-adapted animal were pooled after lens-removal
and homogenized in 0.85 ml 20mM MOPS containing 1.5% lauryl maltoside
and 0.2 M hydroxylamine hydrochloride. The homogenate was extracted on
ice for 3h and centrifuged for 15 min at 135.000 xG at rmax in a Beckman
TL100 centrifuge. The change in absorbance at 498 nm was measured with
a Spectronics Genesys 5 after bleaching (60s at 10 cm with a 60W bulb)
and used to calculate the content of rhodopsin per eye. (Absorbance coefficient
of rhodopsin at 498 nm = 42 000 M-1 cm-1 )
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Results:
MerKD. At postnatal day (P) 25 the knock-out animals contained 67.3%
(p<0.01) more rhodopsin than control animals. These levels drop to almost
normal at P40 (+14.7% p=0.3) and by P60 there is hardly any rhodopsin left
in the retina (-96.8% p<0.05)
P23H. The Rhdopsin levels in all three lines of P23H mutants corresponded
very well with previous structural and functional levels of these animals:
P23H-1 rats have 57.8% normal at P15 and15.3% at P30. P23H-2 animals contain
71.8% (P60) and 40.5% (P120) compared to normal and P23H-3 rats have 54.7%
at P30 and 44.5% normal at P90.
S334. Line 3 (S334-3) animals contain only 3.5% rhodopsin compared
to control animals at P15, while S334-4 animals have a slower time course:
58.0% at P30, 30.1% at P60 and 15.9% at P120. S334-5 rats have only 7.4%
rhodopsin compared to control animals at P30. Line 7 mutants show a rapid
degeneration, their rhodoopsin levels are down to 60.4% at P15 and 14.4%
at P12. S334-9 animals have almost normal rhodopsin levels at P30 and P90.
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Conclusion:
The fact that rhodopsin levels increase first in the MerKD animals before
degeneration begins corresponds well with the thickness of the outer segment
layer, and is a result of the phagocytosis defect in these animals. Our
results are very similar to observations made in the RCS (Royal College
of Surgeons) rat, an inbred rat model with a similar Mer-mutation. The levels
of rhodopsin in most of the P23H and S334 lines mirror results we have obtained
from structural analysis (outer nuclear layer thickness and rod outer segment
length) as well as ERGs performed on these animals.
S334-9 animals have shown an early onset functional retinal deficit in contrast
to normal structural properties. These results here now show that this deficit
is not due to a lack of functioning rhodopsin. Having described the characteristics
of retinal degeneration in 8 different animal models now offers a number
of approaches for future therapies. |
