Læknablaðið : fylgirit - 03.01.2017, Blaðsíða 53

X V I I I V Í S I N D A R Á Ð S T E F N A H Í
F Y L G I R I T 9 1
LÆKNAblaðið/Fylgirit 91 2017/103 53
Efniviður og aðferðir: Í dag meta röntgenlæknar umfang heilahólfa-
stækkunar út frá röð tvívíðra segulómmynda. Við höfum þróað nýstár-
legar myndvinnsluaðferðir, sem flokka og merkja á sjálfvirkan hátt mis-
munandi hluta heilahólfa út frá þrívíðum segulómmyndum í von um
að geta greint fullorðinsvatnshöfuð án inngripa. Aðferðin samtvinnar
vefjaflokkunaraðferð, sem byggir á myndbútum, við aðferð sem byggir
á myndmátun fjölda fyrirfram merktra mynda og getur á nýstárlegan
hátt merkt hliðlægu heilahólfin tvö ásamt þriðja og fjórða heilahólfi
einstaklinga með stækkuð heilahólf.
Niðurstöður: Sjálfvirkar merkingar með okkar aðferð voru bornar
saman við tvær flokkunaraðferðir í fremstu röð og nákvæminsmæl-
ingar gerðar með hliðsjón af handvirkum merkingum heilahólfa í 14
sjúklingamyndum. Dice stuðull fyrir skörun sjálfvirku og handvirku
merkinganna sýnir umtalsverða bætingu okkar aðferðar, sér í lagi á
þeim sjúklingum með alvarlegustu heilahólfastækkunina, þar sem hinar
tvær aðferðirnar bregðast.
Ályktanir: Niðurstöður okkar benda til að aðferð okkar geti gagnast við
greiningu og betri skilgreiningu á sérkennum fullorðinsvatnshöfuðs.
Aðferðin nýtist að auki rannsóknum á öðrum heilahrörnunarsjúkdómum
eins og Alzheimer sjúkdómi, sem oft kemur upp í mismunagreiningu á
fullorðinsvatnshöfði.
E 155 Chitosan-peptide conjugates as effective antimicrobial agents
Priyanka Sahariah1, Kasper K. Sørensen2, Martha Á. Hjálmarsdóttir3, Ólafur E.
Sigurjónsson4, Knud J Jensen2, Már Másson3, Mikkel B. Thygesen2
1Pharmaceutical Sciences, University of Iceland, 2University of Copenhagen, 3University of
Iceland, 4Landspitali University Hospital
prs1@hi.is
Introduction: Antimicrobial peptides (AMPs) hold great promise as
potential biopharmaceutical drugs for the treatment of infections but are
limited due to their toxicity, high minimum inhibitory concentration and
low selectivity for bacterial membranes. The aim was to improve antim-
icrobial activity and reduce hemolytic toxicity of the AMP, anoplin, by
coupling multiple copies to a linear, biocompatible polymer, chitosan, for
multivalent display.
Methods: Anoplin having either an N-terminal or a C-terminal propargyl
group was synthesized by solid-phase synthesis. TBDMS-chitosan was
utilized for synthesizing 2-azidoacetylchitosan derivatives having varying
degree of substitution (DS), which were then coupled to anoplin through
either N or C-terminus using click chemistry. Characterization was done
using 1H and COSY-NMR, HSQC, HMBC, IR and CD spectroscopy.
Antibacterial activity was assayed by Broth microdilution method and
toxicity against human red blood cells.
Results: Chitosan-anoplin conjugates displayed enhanced antibacterial
properties towards Staphylococcus aureus, Enterococcus faecalis, Escherichia
coli and Pseudomonas aeruginosa in comparison to anoplin. The highest
activity amongst the conjugates was observed towards Escherichia coli
with an MIC value as low as 4 µg/mL. The N and the C-terminal conju-
gates exhibited an increasing order of activity with increasing DS towards
Staphylococcus aureus and Escherichia coli. The N-PEP-CS conjugates
showed a drop in activity with increasing DS, while C-PEP-CS conjugates
showed similar activity towards Enterococcus faecalis and Pseudomonas
aeruginosa. All the conjugates exhibited reduced toxicity towards human
red blood cells in comparison to the parent peptide.
Conclusion: Chitosan-peptide conjugates displayed improved antibacter-
ial properties and significantly lower hemolytic toxicity.
E 156 Self-assembled nanoparticles of carboxymethyl cellulose
(CMC) and beta-cyclodextrin (HTMAPβCD) polymer for antibiotics
targeted drug delivery
Agnieszka Popielec, Þorsteinn Loftsson
Faculty of Pharmaceutical Science, University of Iceland
agp9@hi.is
Introduction: Due to increasing bacterial resistance for antibiotics the
development of new drug delivery systems becomes one of the most
important pharmaceutical field. Materials with intrinsic microbial act-
ivity like quaternized polymers help in overcoming the limitations of
traditional antibacterial therapeutics. Nanoparticles (NPs) containing
quaternized modified cyclodextrins may exhibit additional properties like
enhanced encapsulation and solubilization of antimicrobial drugs. This
study describes simple method for preparation of stable NPs consisting
of CMC and positively charged HTMAPβCD with diameter of approx-
imately 300nm.
Methods: All the studies were designed to prepare and characterize the
particles in the nano size range. Dynamic light scattering (DLS) method
was used to measure the mean hydrodynamic diameter of the NPs and
to obtain particles size distribution profile. Aqueous samples of pH 5.5
and with final concentration of 0.5 mg/ml (w/v) were examined at room
temperature to determine the physical stability of the NPs during storage,
upon dilution and addition of NaCl, also in acidic (pH 3) and neutral (pH
7.4) media.
Results: The DLS measurements showed that at room temperature the
NPs maintained size around 300 nm and the same size distribution
profile for more than 40 days. They are stable against sodium chloride
concentration close to isotonic conditions and are resistant towards
dilution up to 200-fold and chemically stable at physiologic pH.
Conclusions: The NPs prepared and characterized in this study are a
promising candidates as drug delivery systems. Since they are stable at
physiological conditions they may be use as carriers for intravenously
administrated antibiotics.
E 157 A chemo-systematic and taxonomic revisit to the lichen
Cetraria islandica
Maonian Xu1, Starri Heiðmarsson2, Elín S. Ólafsdóttir1, Margrét Þorsteinsdóttir1,
Sesselja Ómarsdóttir1
1Faculty of Pharmaceutical Sciences, University of Iceland, 2Icelandic Institute of Natural
History
xum1@hi.is
Introduction: The lichen Cetraria islandica, or Iceland moss, is a symbiot-
ic association of green algae, fungi and bacteria. It has been used in
traditional medicine to treat bronchial and inflammatory conditions,
gastritis and ulcers. However, the taxonomy of Iceland moss is still
controversial and its chemical diversity is much underestimated, which
would trigger problems in the authentication and standardization of
herbal products. Thus, we aimed to understand both chemical diversity
and biodiversity of Cetraria islandica.
Methods and data: In total 141 lichen specimens have been collected
around Iceland from 2012 to 2016. Chemical diversity of biodiversity
of Cetraria islandica in Iceland was studied using metabolite profiling
and molecular phylogenetics, where chemical data were analyzed using
MarkerLynx and phylogeny using Bayesian Inference.
Results: Three chemotypes of Iceland moss were identified in Iceland,
which differ in the presence of fumarprotocetraric acid (FA) and