Læknablaðið - 15.06.1997, Page 75

LÆKNABLAÐIÐ 1997; 83
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cataract extraction and generally to surgery of the
anterior segment.
A-4. Linkeage of Macular Corneal Dys-
trophy (MCD) to chromosome 16q: evi-
dence that MCD types I and II are due to
the same locus
Friðberl Jónasson*, Vance JM**, Lennon F**,
Sarrica J**, Damji K**, Pericak-Vance MA**,
Klintworth GK**
From The *Department of Ophthalmology, Uni-
versity of Iceland, Reykjavík, Iceland, **Duke
University, Durham, NC, USA
Introduction: MCD is an autosomal recessive
disorder leading to opacity of the cornea and
visual loss. The proposed defect is in the bio-
synthesis of keratan sulfated (KS) corneal pro-
teins. MCD has been divided into two types.
Type I lacks an immune response to KS derived
antibodies while type II demonstrates a positive
reaction in serum and corneas.
Material and methods: Seventeen USA and
Icelandic MCD families (13 type I and four type
II) were initially genotyped with 208 genomic
markers. Subsequent genealogy analysis revealed
that four of the Icelandic families could be con-
nected into a single, highly consanguineous fam-
ily. These families can be traced back 15 gener-
ations to a single individual, suggesting a founder
effect in this population.
Results: Significant linkage was found for a
series of markers on chromosome (chr) 16q. The
peak LOD score was with D 16S518 (z(theta)
=8.11@theta=0.05). Significant heterogeneity
(p<0.05) was observed with one American MCD
type I family excluding linkage to this chr 16 re-
gion. The remaining American and Icelandic
families demonstrated linkage to chr 16. Haplo-
type analysis localizes MCD to a Ð15 cM region
flanked by cent-D16S512 and D16S507-tel.
Conclusion: Both MCD type I and type II fam-
ilies showed evidence for linkage to the same
chromosomal region, suggesting they are due to a
mutation at the same primary locus. Therefore,
the division of MCD into types I and II based on
their KS antibody response appears due to a yet
unknown secondary effect. This hypothesis is fur-
ther supported by the large Icelandic family
which includes nuclear families of both MCD
types. To date, common haplotypes have not
been ovserved, indicating the potential for fur-
ther refinement of the MCD region by developing
additional markers in this area.
A-5. Topical acetazolamide in 2-hydrox-
ypropyl-I5-cyclodextrin (HPBCD) eye
drops lowers intraocular pressure in hu-
mans
Einar Stefánsson, Sigríður Þórisdóttir, Hafrún
Friðriksdóttir, Þorsteinn Loftsson, Jóhannes Kári
Kristinsson, Guðrún J. Guðmundsdóttir
From The Departments of Ophthalmology and
Pharmacy, University of Iceland, Reykjavík, Ice-
land
Purpose: The purpose of this study is to create
an effective topical preparation for use in glauco-
ma. HP6CD increases the solubility of lipophilic
drugs in aqueous solutions, such as eye drops and
may also enhance the availability of the drug to
the ocular surface. We have prepared eye drops
containing 18% HPBCD and 1% Acetazolamide
in aqueous solution. We measured the intraocular
pressure (IOP) lowering effect of the eye drops in
rabbits and human patients with ocular hyperten-
sion.
Material and methods: Resting IOP level in ten
English brown rabbits was determined with pneu-
matonometry before application. A single drop
was administered to one eye and IOP measured
every 30 minutes up to five hours after instillation
of the drop. Nine patients with ocular hyperten-
sion used the eye drops in one eye and IOP was
measured with applanation tonometry at three
timepoints on days 0, 3, 7,14 and 28.
Results: In both species, statistically significant
lowering of IOP was found. In the rabbits, maxi-
mum decline was 2.7+/-0.95 torr (mean+/-
S.E.M., n=10, p<.001) 2.5 hours after instilla-
tion. In comparison, Timolol maleate (Bloca-
dren®) and 0.3% Ethoxyzolamide showed maxi-
mum decline of 5.6+/-1.1 torr and 2.6+/-0.7 torr
1.5 hours after instillation respectively (mean+/-
S.E.M., n=10, p<.001). In patients with ocular
hypertension acetazolamide lowered IOP by
3.6+/-0.4 torr or 16.7+/-2.0% (mean+/-S.E.M.,
n=7, p<.001) on day 14. No toxic effects were
observed.
Conclusion: 1% Acetazolamide-HPBCD is a
non-toxic and effective IOP lowering eye drop. It
may be a useful glaucoma medication, alone or in
combination with other drugs.
A-6. Mitomycin trabeculectomy for
glaucoma with poor surgical prognosis
compared with standard trabeculectomy
with good prognosis
Neelakantan A, Stewart JFJ, Jay JL
From The Tennent Institute of Ophthalmology,