bluuebunny/crossref_metadata_2025_split huggingface dataset:
Safety of the anterior vitreous detachment induced by microplasmin, pharmacologic vitreolysis to separate the posterior capsule from the anterior hyaloid
Authors: VAN LOOVEREN J 
Published: November 2010

Abstract Purpose The aim of this project is to establish the safety of the use of microplasmin in the vitreolenticular interface to promote the separation of the anterior hyaloid from the posterior capsule. Methods The safety of the use of microplasmin solution will be examined in 24 eyes of 12 rabbits after having performed a cataract surgery and a primary posterior continuous curvilinear capsulorhexis and having exposed the anterior hyaloid interface with a solution of different doses of microplasmin (125µg or 250µg in 0.1ml balanced salt solution)and having left this solution in place during different time intervals starting from 5 minutes to one hour. The rabbit eyes will be examined at well‐defined time intervals: day 1 and 7, month 1,2,3,6 and 12. Slitlamp examination and OCT‐SLO imaging will be performed to monitor ocular inflammation, visual axis reproliferation and anterior vitreous anatomy. Conclusion Congenital cataracts, whether or not combined with persistent fetal vasculature may present different degrees of congenital dysgenesis of the vitreolenticular interface. Pharmacological separation of the interface between posterior lens capsule and anterior hyaloid would be benificial to improve the surgical outcome. Therefore the feasibility, safety and clinical application of intravitreal injection of microplasmin for this indication need to be examined first.
Retinal vessel diameter affects oxygen saturation measurements
Authors: HARDARSON SH , BERGVINSSON HR , STEFANSSON E 
Published: November 2010

Abstract Purpose To test whether retinal vessel oxygen saturation measurements are affected by vessel diameter and to compare saturation between the temporal and nasal retina. Methods The Oxymap retinal oximeter is based on a fundus camera. It measures light absorbance at two wavelengths of light and calculates oxygen saturation in retinal vessels as well as vessel diameter. Measurements were performed on 12 healthy individuals. The effect of vessel diameter on saturation measurements was tested by measuring before and after the first bifurcation in the retina (1st degree parent vessels and 2nd degree daughter vessels). Arteriolar saturation can be assumed to be equal before and after bifurcation. Results The ratio between oxygen saturation in 1st degree parent arteriole and 2nd degree daughter arteriole was 0.97±0.02 (mean±SD). The ratio was significantly lower than the theoretical value of 1.00 (p<0.001, n=12) The corresponding ratio for venules was 0.90±0.04 (p<0.001). Oxygen saturation was 94±6% in 1st degree superotemporal arterioles and 99±6% in superonasal arterioles (p=0.057). Oxygen saturation in inferotemporal arterioles was 89±6% and 95±4% in inferonasal arterioles (p=0.009). There was no significant difference in venous saturation between temporal and nasal quadrants. Conclusion Measured oxygen saturation is lower in 1st degree parent vessels than in their 2nd degree daughter branches. This indicates that retinal vessel diameter affects oxygen saturation measurements. The higher measured saturation in the nasal arterioles, compared to temporal arterioles, may also be due to the fact that the nasal vessels are narrower. A correction for the effect of vessel diameter should be incorporated into oxygen saturation measurements.
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Reproducibility of retinal vessel hemoglobin oxygenation saturation in healthy subjects
Authors: LASTA M , BOLTZ A , SCHMIDL D , PALKOVITS S , PEMP B , GARHOFER G , SCHMETTERER L 
Published: November 2010

Abstract Purpose Only recently systems for the measurement of hemoglobin oxygenation saturation in retinal vessels became commercially available. In the present study a fundus camera equipped with a dual wavelength transmission filter and a CCD camera was used (Imedos, Jena, Germany). Two monochromatic fundus images at 548 and 610 nm were recorded simultaneously and the oxygen saturation (SaO2) was calculated based on the optical density ratio. Methods A study on test/retest, short‐term and day‐to‐day reproducibility of the technique was done in 14 healthy subjects. To assess test/retest variability fundus images were taken at each measurement cycle. To assess short‐term reproducibility 2 such cycles of 3 fundus images were done within 15 minutes. Finally, this cycle of measurements was done on the next day to assess day‐to‐day reproducibility. Data were evaluated separately for retinal branch arteries and branch veins. The reproducibility was calculated using the standard deviation (SD) of the measurements. Results In retinal branch veins the SaO2 was 49±9% (range 32‐69%, 38 vessels) and in retinal branch arteries 91±8% (range 77‐112%, 40 vessels). The test/retest SD was 5.4±3.7% in retinal veins and 3.0±2.3% in retinal arteries. The short term SD was 4.7±3.7% in retinal veins and 2.9±2.1% in retinal arteries. The day‐to‐day SD was 6.2±4.1% in retinal veins and 4.0±2.8% in retinal arteries. Conclusion Our data indicate that the test/retest, short‐term and day‐to‐day reproducibility of the technique is acceptable. Hence, the system may be adequate to follow oxygen saturation during disease processes. The data obtained in retinal branch arteries indicates, however, that the validity of measurements requires further studies.
Role of nitric oxide in optic nerve head blood flow regulation during isometric exercise in healthy humans
Authors: SCHMIDL D , BOLTZ A , LASTA M , KAYA S , PEMP B , GARHOFER G , FUCHSJAEGER‐MAYRL G , SCHMETTERER L 
Published: November 2010

Abstract Purpose Nitric oxide (NO) is an important regulator of optic nerve head (ONH) blood flow in humans. We have previously shown that NO is also involved in choroidal blood flow regulation during isometric exercise. Inhibition of NO synthase (NOS) has been reported to shift choroidal pressure–flow curves during squatting to the right. The hypothesis for the present study was that inhibition of NOS may also influence ONH blood flow during isometric exercise. Methods To test this hypothesis, a randomized, double‐masked, placebo‐controlled, three‐way crossover study was performed in 18 healthy volunteers. Subjects received on different study days intravenous infusions of NG‐monomethyl‐ L‐arginine (L‐NMMA), phenylephrine, or placebo. During these infusion periods, subjects were asked to squat for 6 minutes. ONH blood flow was assessed with laser Doppler flowmetry, and ocular perfusion pressure (OPP) was calculated from mean arterial pressure and intraocular pressure. Results L‐NMMA and phenylephrine increased resting OPP (p < 0.001 versus baseline), but only L‐NMMA reduced resting ONH blood flow (p = 0.02 versus baseline). The relative increase in OPP during isometric exercise was comparable with all drugs administered (p = 0.69). In addition, the change of ONH blood flow was comparable with all administered drugs (p = 0.43). Conclusion These data indicate that NO plays an important role in the regulation of ONH blood flow at baseline, but does not change the response of ONH blood flow during isometric exercise.
Comparison of algorithms for oximetry in vivo and ex vivo
Authors: DE BROUWERE D , DAINTY C 
Published: November 2010

Abstract Purpose Several authors have proposed a number of algorithms to extract the oxygen saturation in retinal blood vessels based on multispectral image analysis. We evaluated the outcomes of seven known algorithms based on hyperspectral retinal images. Methods Hyperspectral images are acquired using a fundus camera where a slit spectrograph is registered onto a retinal image. This combination compromises both accurate spatial and spectral information over the selected slit. Hyperspectral image analysis was used as input for the oximetry calculations described in the literature. We used a model eye to evaluate the different techniques in a controlled setup. Defibrinated horse blood was perfused through microtubules placed in front of a white (spectralon) background. Oxygen saturation was controlled by mixing different concentrations of sodium dithianate in the blood. Results Oxygen saturation was varied in five equidistant steps between 0 and 1. We correlated the outcomes to the metric of Harvey et al. [Biomed Optics 6631, 2007] Linear correlation with other algorithms resulted in r2 values between 0.881 and 0.985, however we observed a large discrepancy of the slope of each correlation line. The algorithms were also evaluated in images recorded in five healthy volunteers. In all techniques, veins could be separated from arteries by their reduces oxygen saturation, although values varied strongly between the different techniques. Conclusion Our findings confirm the working of a number of noninvasive retinal oximetry algorithms. Different readings can be can be attributed to an offset caused by an uncertainty of pigmentation and scattering parameters in the calibration procedure.
Dynamic retinal vessel analysis – how different parameters create the whole picture
Authors: LANZL I , KOTLIAR K 
Published: November 2010

Abstract Purpose Dynamic vessel analysis is usually associated with the observation of the reaction of retinal vessels to a defined stimulus. The data which is generated this way may be further analysed with respect to the dynamic unstimulated and stimulated vessel behaviour. Assessment of different parameters may highlight different aspects of the underlying disease. Methods Vessel diameters of retinal vessel segments were assessed by Dynamic Vessel Analyzer (DVA) in healthy volunteers of different age groups and patients with diabetes, glaucoma and systemic hypertension. Mathematical analysis of unstimulated vessels was used to describe vessel wall characteristics. Methods of signal analysis including Fourier Transformation, spectral filtration, auto‐ and cross correlation were applied to evaluate characteristic oscillations and pulse wave propagation along the vessel. Results Characteristic different vessel behaviour and vessel wall conformation are obtained by dynamic quantitative evaluations from the unstimulated vessels in physiologic aging and disease. Conclusion Dynamic vessel analysis includes information which may lead to further understanding of the vascular status and underlying disease pathology. It is also feasible to assess pulse wave velocities in retinal arterioles und thus clinically characterize the elasticity of the upstream vasculature in health and disease.
Are the Meibomian glands “hair follicles without a hair shaft” ?
Authors: KNOP E , KNOP N 
Published: November 2010

Abstract Purpose The Meibomian glands (MG) are atypically large sebaceous glands in the eyelids with numerous generations of secretory acini along an extensive central duct. They share similarities with the ciliary hairs in development, and hyper‐keratinisation leading to obstructive MG dysfunction (MGD) represents the typical pathology. It was hence investigated which structural similarities they share with cilia. Methods Conjunctival whole‐mounts including the lid margin from ten normal human body donors were embedded in paraffin. Serial sections were stained by H&E, Masson‐Goldners stain and by immunohistochemistry (IHC) against cytokeratins and associated proteins. Results The terminal part (excretory duct) of the MG central duct is an ingrowth of epidermis similar to the hair follicles of the cilia. Characterization of individual cytokeratinis by IHC showed that CK14, a marker for undifferentiated cells, was expressed in the basal cell layer of the skin, MG ducts and the secretory acini. The excretory duct epithelium expressed the skin keratin CK10 and the keratinisation marker involucrin but in proximal direction along the central duct full cornification as well as both markers were gradually lost. Filaggrin, however, a marker for incipient stages of keratinisation located in keratohyalin granules continued in the superficial epithelial layer all along the MG ductal system. Conclusion All parts of the normal human MG ductal system have signs of incipient keratinisation and preserve a commitment to full cornification. This supports the assumption that the MG are basically “hair follicles without a hair shaft” in which the progression to full epithelial cornification is apparently blocked during embryological development but may reoccur under pathological influences. Support DFG KN317/11
The challenge of interpreting the histomorphology of human fetal lenses
Authors: LOEFFLER KU , HERWIG MC , HOLZ FG , MüLLER AM 
Published: November 2010

Abstract Purpose On histology, the crystalline lens is – especially in fetal and infant eyes ‐ an organ susceptible to numerous artifacts. Nevertheless, evaluation of the lens is often of paramount importance in the classification of fetal syndromes or forensic questions. Thus, the aim of our study is to evaluate various factors that might have an impact on lens histomorphology. Methods Our collection of eyes by now comprises more than 500 specimens from fetuses with a gestational age between 8 and 38 weeks, including a variety of syndroms. Apart from induced fetocid, death occured due to spontaneous abortion or post‐natally. Specimens were fixed in formalin, and in selected cases one eye was put into Karnovsky's solution for comparison. All systemic findings as well as data related to the termination procedure were recorded. ‐ Some individual cases shall be presented to demonstrate the variability of histopathologic findings. Results Most of the eyes revealed lens features different from the descriptions available in textbooks. At all ages, there were various morphologic changes particularly of the subcapsular cortex, compatible with cataractous lenses in the adult, while the well‐known phenomenon of an indentation at the posterior pole was seen especially in older fetuses. The difference in fixatives had only a moderate impact on structural alterations. Conclusion Alterations in fetal lens morphology are extremely frequent and variable. These can be due to delayed fixation, cutting artifacts and other variables and have to be carefully taken into account particularly when interpreting post‐mortem findings. The diagnosis of a fetal cataract should therefore only be made with great caution and not without a careful macroscopic evaluation.
Identification of a new locus in autosomal dominant retinitis pigmentosa and strategy for molecular diagnosis
Authors: MANES G , COUSTES‐CHAZALETTE D , BOCQUET B , DELAERE V , DEVOS A , DHAENENS CM , HéBRARD M , MEUNIER I , HAMEL C 
Published: November 2010

Abstract Purpose Autosomal dominant retinitis pigmentosa (adRP) affects approximately 1 in 12,000 individuals. To date, 21 adRP genes have been identified accounting theoretically for 44.7% of adRP families; therefore, genetic defects in many patients are yet to be identified. This study was intended to provide information on prevalence of known adRP genes in France and to localize new genes and loci. Methods Microsatellite markers for the 21 adRP genes were used to genotype large families. Non excluded genes were then sequenced. For some families, we performed a whole‐genome SNP analysis using Affymetrix 250K or 6.0 chips. For small families, the 8 most frequently mutated adRP genes were sequenced (in full for RHO, in hot spots only for PRPF31, RDS, RP1, PRPF8, IMPDH1, NRL and PRPF3). Results Hitherto 18 adRP families were studied by indirect genotype analysis. Of these, 15 have shown mutations in known genes and 2 are still in progress. For the last family, one new locus was identified by whole‐genome SNP analysis and confirmed by microsatellite genotyping defining a 43‐Mb locus on chromosome 2. The direct sequencing approach was performed on 143 proband DNAs (completely for the first 50 patients and only RHO for the 93 other patients). A causative mutation was found for 20 families (14%), among which 9 out of 11 were novel. Conclusion The preliminary results, on this limited cohort, showed that the prevalence of known genes is probably underestimated in the literature because the causative mutation was found for 15 families out of 18 (83%). However one new locus has been identified and is under active investigation.
Multifactorial traits in keratoconus: how and why traits show family resemblance
Authors: GAJECKA M , KULINSKA K , KAROLAK J , CZUGALA M , RYDZANICZ M , WAMPOLE J , MOLINARI A , PITARQUE J , BEJJANI B , NOWAK D 
Published: November 2010

Abstract Purpose Mapping and genome sharing among affected individuals continue to be important for establishing a link between a genomic variant and its phenotypic consequences. Several loci responsible for a familial form of keratoconus (KTCN) have been mapped, however; no mutations in any genes have been identified for any of these loci. Here we present further sequencing results of candidate keratoconus genes localized to 13q32 and 13q34 and accompanying linkage analyses performed in Ecuadorian families. Methods Genes were screened by standard techniques using 48 genomic DNA samples from individuals from family KTCN‐014 and selected affected and unaffected individuals from other Ecuadorian families. Coding exons and intron‐exon boundaries of the genes were evaluated. Additional bioinformatics analyses were carried out based on the genomewide scan data obtained from 79 patients with keratoconus and 66 healthy family members. Results Sequencing of COL4A1 and COL4A2 genes at 13q34 have been completed. Several single nucleotide polymorphisms were identified in coding and non‐coding regions. Haplotype analysis in family KTCN‐014 at 13q32 revealed three sequence variants segregating with keratoconus phenotype. Bioinformatics analyses revealed distinct keratoconus loci in particular Ecuadorian families indicating complexity of genetics in familial keratoconus. Conclusion Our results show high complexity of genetics in familial keratoconus
Mutation in the Bmpr1b gene affects optic nerve development
Authors: GRAW J , WEBER S , PUK O , WAGNER S , KLAFTEN M , THIELE F , FUCHS H , HRABé DE ANGELIS M 
Published: November 2010

Abstract Purpose Systematic analysis of the ocular defects in a new mouse mutant carrying a Bmpr1b mutation. Methods The Bmpr1b mutants were analyzed by slit lamp, funduscopy, laser interference biometry, electroretinography, virtual drum, histology and in‐situ hybridization. Results The new Bmpr1b mutant is characterized by a T‐>G transversion in the splice donor site of exon 10. The mutants show irregular forelimb and hindlimb morphology, brachydactyly, irregular cartilage development and alterations in the reproductive system. The lens is clear, but in homozygous mutants, an enlarged optic disc was observed by funduscopy. The eyes are slightly larger, which is mainly due to an increased aqueous humor. Electroretinography demonstrated a more rapid decline of the b‐wave indicating a less efficient transmission of electric stimuli within the retina. Moreover, homozygous mutant mice show also almost no response to moving stripes as compared to the wild type mice. Histological analysis indicated dramatic changes in the optic nerve head. Analysis of the embryonic development of the eye showed that the expression area of Pax6 expands posterior, and concomitantly, Pax2 expression (which is regular at embryonic day 11.5) is repressed at embryonic days 15.5 and 17.5 at the optic nerve head. Conclusion The T‐G mutation in the splice donor site of exon 10 of the Bmpr1b gene leads to a recessive hypoplasia of the optic nerve head, which is mainly caused by repression of Pax2 expression in the late phase of embryogenesis.
Novel mutation in the TGFBI gene in a patient with a late‐onset lattice corneal dystrophy
Authors: OLDAK M , SZAFLIK JP , MAKSYM RB , UDZIELA M , FRANASZCZYK M , PIOSKI R , SZAFLIK J 
Published: November 2010

Abstract Purpose To report the clinical and molecular findings in a patient with late‐onset lattice corneal dystrophy and a novel Leu565Pro mutation in the TGFBI gene. Methods The diagnosis of lattice corneal dystrophy (LCD) was performed by visualization of characteristic lesions with slit‐lamp examination and by in vivo confocal microscopy. Mutation screening of coding regions of the TGFBI gene was done by PCR amplification and direct sequencing. Results We found a novel c.1694T>C heterozygous missense mutation in exon 13 of the TGFBI gene, which predicts the substitution of a leucine for a proline at codon 565 (Leu565Pro). Sequencing of all remaining exons of the TGFBI gene did not show any alterations. Conclusion The mutant codon 565 is located at the C‐terminus in the region corresponding to the fourth fascilin domain of the TGFBI protein. The novel variant adds to a number of previously reported mutations causing lattice corneal dystrophy and located in this region.
Biomechanical analysis of the pressure‐volume relationship in a statically loaded human eye
Authors: STEIN AA , MOISEEVA IN 
Published: November 2010

Abstract Purpose To develop an approach for estimating the mechanical characteristics of the individual eye in the ophthalmologic procedures based on static load application (tonometry, et al.). Methods The fibrous coat is mathematically modeled as a soft elastic shell (cornea) connected with an elastic system that mainly consists of the sclera and is characterized by a single elastic constant describing its response to the intraocular pressure. A function representing the intraocular volume as a function of two variables, the intraocular pressure and the load applied, called the volume function is introduced. This function is then specified on the basis of a simple model characterized by two elastic constants in the case of an applanating load. Results A general method of estimating the integral elastic behavior of the individual eye is developed and specific relationships between elastic constants important in different loading processes are obtained. Conclusion The method developed makes it possible to reliably estimate the integral elastic behavior of the fibrous coat and, as a result, to obtain more correct data on the intraocular pressure and other mechanical characteristics. Although in different loading processes (for example, in tonometry and inflating the eye by a liquid volume) different integral elastic contacts are involved, the model proposed provides a means for obtaining efficient approximate relationships between these constants.