AIBILI-Association for Innovation and Biomedical Research on Light and Image

Polypoidal Choroidal Vasculopathy and Photodynamic Therapy with Verteporfin.

Silva, R.M., Figueira, J.P., Cachulo, M.L., Duarte, L., Faria de Abreu, J.R., Cunha-Vaz, J.G.

Graefes Archive for Cinical and Experimental Ophthyalmology. 2005, 243: 973-979.

2005

Eslicarbazepine acetate (BIA 2-093: Relative bioavailability and bioequivalence of 50 mg/mL oral suspensions and 200 mg and 800 mg tablet formulations.

Fontes-Ribeiro, C., Nunes, T., Falcão, A., Neta, C., Lima, R., Tavares, S., Almeida, L., Macedo, T., Soares-da-Silva, P.

Abstract:
Objective: To investigate the dosage form proportionality and food effect of the final tablet formulation of eslicarbazepine acetate (ESL) in healthy volunteers.

Methods: This was a randomized, three-way crossover, single-centre study in 18 healthy volunteers. Subjects received a single dose of oral ESL 800 mg following a standard meal in one period, and following 10 hours of fasting in two separate periods (in the form of one 800 mg tablet [reference] or two 400 mg tablets [test]). The statistical method was based upon the 90% confidence interval (CI) of maximum observed plasma drug concentration (Cmax), area under the plasma concentration time curve (AUC) from time zero to the last sampling time at which concentrations were at or above the lower limit of quantification (AUCt) and AUC from time zero to infinity (AUC[infinity]) geometric means ratios (GMRs) of BIA 2-005, the enantiomeric mixture of the ESL active metabolite eslicarbazepine and its enantiomer R-licarbazepine. Bioequivalence was assumed when the 90% CI of the test/reference GMR fell within the bioequivalence acceptance interval (80.00, 125.00).

Results: Following a single dose of ESL 800 mg in the forms of two 400 mg tablets and one 800 mg tablet, the test/reference GMR (%) and 90% CI for Cmax, AUCt and AUC[infinity] were 100.78% (93.91, 108.16), 100.37% (97.82, 102.99) and 100.48% (97.91, 103.13), respectively. Following administration of one 800 mg tablet in fed (test) and fasting (reference) conditions, the test/reference GMR and 90% CI for Cmax, AUCt and AUC[infinity] were 100.96% (94.08, 108.35), 96.79% (94.34, 99.32) and 96.75% (94.27, 99.29), respectively. Treatments were well tolerated.

Conclusions: The bioequivalence criteria between the ESL 400 mg and 800 mg tablets were met and dosage form proportionality was demonstrated. The presence of food had no influence on ESL pharmacokinetics, indicating that ESL can be administered without regard to meals with no significant effects on drug disposition or extent of systemic exposure.

Drugs R D 2005;6(5):253-60.

2005

Mapping the Human Blood-Retinal Barrier Function.

Bernardes R., Dias J., Cunha-Vaz J.

The aim of the work herein presented is to map blood-retinal barrier function by measuring retinal fluorescein leakage from the blood stream into the human vitreous using a confocal scanning laser ophthalmoscope (CSLO). Existing methods for the assessment of fluorescein leakage into the human vitreous are based on the qualitative evaluation of fluorescein angiographies (FA) and on volume measurements, as performed by the Fluorotron Master. A new procedure is presented capable of measuring fluorescein leakage into the vitreous while simultaneously imaging the retina. The present methodology computes the fluorescein leakage in a fully automated way, based on the three-dimensional fluorescence distribution in the human eye by using a single data acquisition. The processing includes signal filtering, volume alignment and profile deconvolution. The deconvolved profile obeys the established physical model. Representative cases shown are: a healthy eye; an eye with drusen from a nondiabetic person; a photocoagulated eye; and an eye with nonproliferative diabetic retinopathy. The results are in agreement with previous findings and go a step further by making possible its daily usage in a clinical setup based on currently available instrumentation.

IEEE Trans Biomed Eng 2005;52:106-116.

2005
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1369593

Nonproliferative retinopathy in diabetes type 2. Initial stages and characterization of phenotypes.

Cunha-Vaz J., Bernardes R.

This review addresses the initial stages of nonproliferative diabetic retinopathy in diabetes type 2. The natural history of the initial lesions occurring in the diabetic retina has particular relevance for our understanding and management of diabetic retinal disease, one of the major causes of vision loss in the western world.Diabetic retinal lesions are still reversible at this stage opening entirely new opportunities for effective intervention. Four main alterations characterize these early stages of diabetic retinopathy: microaneurysms/hemorrhages, alteration of the blood–retinal barrier, capillary closure and alterations in the neuronal and glial cells of the retina.These alterations may be monitored by red-dot counting on eye fundus images and by fluorescein leakage and retinal thickness measurements. A combination of these methods through multimodal macula mapping has contributed by identifying three different phenotypes of diabetic retinopathy.They show different types and rates of progression which suggest the involvement of different susceptibility genes.The identification of different phenotypes opens the door for genotype characterization, different management strategies targeted treatments.

Progress in Retinal and Eye Research. 2005; 24:355-377.

2005
http://rihuc.huc.min-saude.pt/bitstream/10400.4/660/1/Nonproliferative%20retinopathy%20in%20diabetes%20type.pdf

Multimodal Functional and Morphological Nonrigid Image Registration.

Bernardes R., Baptista P., Dias J., Cunha-Vaz J.

The aim of this work is to present the registration of two different and complementary imaging modalities of the human eye fundus. One is a widely used modality consisting of a color photograph of the human retina and the other consists of a functional imaging modality that assesses, in vivo, the human blood-retinal barrier function. The need for the nonrigid registration of these two modalities is demonstrated and is due to the acquisition mode of the functional modality. The two modalities here with registered are from two different devices, have different resolutions and different fields-of-view, i.e., the smaller is only a subset of the larger one. In this paper, all these problems were addressed and a solution proposed.

IEEE International Conference on Image Processing ICIP-05, pages 11331136, September 11-14, 2005.

2005
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1529955

Distortion free registration between multifocal ERG and retinal leakage analyzer.

Bernardes R., Ferreira J., Baptista P., Sebastião A., Dias J., Cunha-Vaz J.

The aim of the present work is the registration of two functional imaging modalities while simultaneously correcting for the intrinsic distortions present on both. Two recently introduced imaging modalities are used in this work, one that measures the retina response to blue light stimuli and another that measures the blood-retinal barrier function. A deformable registration procedure was developed, comprising a model for saccadic eye movements which allows for an important reduction in the number of parameters which need to be estimated. Finally, simultaneous correction for the intrinsic distortions was achieved through resorting to an additional imaging modality, thus resulting in practice in the registration of three different modalities, the former two of the functional type and the latter of the morphological type.

IFMBE Proceedings, Vol. 11. Prague: IFMBE, 2005. ISSN 1727-1983. – Proceedings of the 3rd European Medical & Biological Engineering Conference – EMBEC´05. Prague, Czech Republic, November 20-25, 2005, pages 1868-1 to 1868-6.

2005

Earmarking retinal changes in a sequence of digital color fundus photographs.

Ferreira J., Bernardes R., Baptista P., Cunha-Vaz J.

This paper presents a novel approach for earmarking retinal changes in a sequence of digital color fundus photographs, using Principal Component Analysis (PCA) and a temporal color-coded scheme so as to improve the representation of the global effect of these changes — its aim is to assist graders in detecting alterations on digital color photographic follow-up time-sequences of the human retina. The color-coded scheme was developed so that: the earliest earmarking color of areas which have been detected in multiple instances in the followup timeline is kept; areas which have suffered changes but have returned to their original appearance are earmarked with a specific color-code. The composite image formed by the projection of the color-code image onto the baseline image used as reference then guides the grader’s attention to changes detected on the fundus photographs.

2005

Multimodal Macula Mapping: study for rigid, perspective and deformable image registration.

Baptista P., Bernardes R., Ferreira J., Dias J., Cunha-Vaz J.

In this work, thirteen image-pairs, composed of a color fundus photograph and a scanning laser ophthalmoscope fluorescein angiography (SLO.FA), were registered by rigid, non-rigid and deformable image registration procedures to assess the need for deformable image registration methods when using SLO.FA modalities. Each registration was quantitatively assessed by three different metrics that showed improved performance of the deformable approach. Moreover, the computed deformation grids demonstrated the infeasibility of global transformation approaches to deal with saccadics, as expected. Also, in the registration of medical images, some knowledge of the acquisition mode and its particularities was shown necessary to successfully achieve good registration results with a reduced search space for the parameters involved.

2005

Simultaneous comparison of relative damage to chromatic pathways in ocular hypertension and glaucoma: correlation with clinical measures.

Castelo-Branco, M., Faria P., Forjaz, V., Kozak, L., Azevedo, H.

Invest. Ophthalmol. Vis. Sci. 2004, 45(2):499-505.

2004

Stabilization of visual acuity with photodynamic therapy in eyes with chorioretinal anastomoses.

Silva, R.M., Faria de Abreu, J.R., Travassos, A., Cunha-Vaz, J.G.

Graefes Arch. Clin. Exp. Ophthalmol. 2004, 242:368-376.

2004