Purpose of this study was to characterize retinal disease in Usher syndrome using fundus autofluorescence and optical coherence tomography. Study included54 patients (26 male, 28 female) aged 7-70 years. There were 18 (33%) USH1 and 36 (67%) USH2 patients. 49/52 (94%) patients were found to carry at least one mutation in Usher genes. Ophthalmological examination included assessment of Snellen visual acuity, color vision with Ishihara tables, Goldmann visual fields (targets II/1-4 and V/4), microperimetry, fundus autofluorescence imaging and optical coherence tomography. Average age at disease onset (nyctalopia) was significantly lower in USH1 than USH2 patients (average 9 vs. 17 years, respectively; p ( 0.01); however no significant differences were found regarding type of autofluorescence patterns, frequency of foveal lesions and CME, rate of disease progression and age at legal blindness. All representative eyes had abnormal fundus autofluorescence of either hyperautofluorescent ring (55%), hyperautofluorescent foveal patch (35%) or foveal atrophy (10%). Disease duration of more than 30 years was associated with a high incidence of abnormal central fundus autofluorescence (patch or atrophy) and visual acuity loss.
COBISS.SI-ID: 547244
Achiasmia is a rare disorder of visual pathway maldevelopment that can show diverse clinical and magnetic resonance imaging spectra. The aim of this studywas to define the characteristics of visual evoked potentials (VEPs) thatdifferentiate abnormal optic-nerve-fibre decussation in children with achiasmia versus children with albinism and healthy children. In four childrenwith achiasmia, the following VEP characteristics were studied and compared to children with ocular albinism and with healthy control children: (a) flash and pattern onset VEP interhemispheric asymmetry; (b) flash N2, P2 and onset C1 amplitudes and latencies; (c) interocular polarity differences ininterhemisphere potentials; and (d) chiasm coefficients (CCs). In the children with achiasmia, VEPs were related to an absence of or reduced optic-nerve-fibre decussation at the chiasm and showed: ipsilateral asymmetry,significantly higher VEP amplitudes over the ipsilateral hemisphere (p ( 0.05), interocular inverse polarity and negative CC. Other VEP features (uncrossed asymmetry and positive CC) were also seen if additional visual pathway maldevelopment (such as severe optic nerve hypoplasia and/or absence of the optic tractus on one side) were associated with achiasmia. In the children with albinism, the VEPs were related to excess optic-nerve-fibre decussation at the chiasm and showed: contralateral asymmetry, significantly higher VEP amplitudes over the contralateral hemisphere (p ( 0.001), interocular inverse polarity and negative CC. In achiasmia and albinism, the VEPs to flash stimulation were more robust and more clearly distinguished between the conditions compared with the VEPs to pattern onset stimulation. VEPs in achiasmia are associated with absent or reduced optic-nerve-fibre decussation, where ipsilateral interhemispheric asymmetry is associated with interocular inverse polarity and a negative CC.
COBISS.SI-ID: 29828313
Purpose: To compare the organization of human and rat ocular medial recti muscles (MR). Methods: The cryosections of human and rat MR were processed formyofibrillar ATPase (mATPase), succinate dehydrogenase and glycerol-3-phosphate dehydrogenase. To reveal myosin heavy chain (MyHC) isoforms, specific monoclonal antibodies against MyHC-1/beta- slow, alpha-cardiac (-alpha), -2a, -2x, -2b, -extraocular (eom), -embryonic (-emb) and -neonatal (-neo) were applied. The MyHC gene expression was studied by in situ hybridization in human muscle. Results: The muscle fibers were arranged in two distinct layers in both species. In the orbital layer most fibers were highly oxidative and expressed fast MyHC isoforms, whereas slow and oxidative fibers expressed MyHC-1 and -alpha, some of them also MyHC-2a, -2x, -eom, very rarely -emb, and -neo. In the global layer, slow fibers with very low oxidative and glycolytic activity and three types of fast fibers, glycolytic, oxidative and oxidative-glycolytic, could be distinguished. The slow medium-sized fibers with mATPase activity stable at pH 4.4 expressed mostly MyHC-1 and -alpha in rat, while in humans they co-expressed MyHC-1 with -2b, -2x, -eom, and -neo. In both species, the fast fibers showed variable mATPase activity after preincubation at pH 9.4, and co-expressed various combinations of MyHC-2b, -2x, -2a and -eom but not -emb and -neo. MyHC-2b expressing fibers were larger and glycolytic, while MyHC-2a expressing fibers were smaller and highly oxidative in both species. To our knowledge, the present study is the first that demonstrated the expression of MyHC-2b in any of humanskeletal muscles. Though the expression of MyHC genes did not correlate with the immunohistochemical profile of fibers in human MR, the expression of MyHC-2b gene was undoubtedly confirmed. (Abstract truncated at 2000 characters)
COBISS.SI-ID: 26132953
Purpose: To determine whether the vitreous levels of interleukin 8 (IL-8) and vascular endothelial growth factor (VEGF) of patients with proliferative diabetic retinopathy (PDR) were associated with poor visual acuity after vitrectomy. Methods: Observational cross-sectional study. Patient clinical characteristics and preoperative eye characteristics (63 eyes): visual acuity,iris neovascularization, vitreous haemorrhage, macular detachment, macular oedema, active retinal neovascularization, neovascularization of the disc, burned out PDR (defined as natural end stage of PDR with inactive membranes without previously performed laser photocoagulation) and panretinal photocoagulation were registered prior to vitrectomy for each patient. Vitreous VEGF and IL-8 levels were measured using the cytometric bead array method. Poor postoperative visual acuity was defined as visual acuity of (20/200 and was checked 2 years after vitrectomy. Results: Twenty-one of the 63 eyes (33.3%) had poor visual acuity after vitrectomy. Univariate analysis showed that vitreous levels of IL-8, the absence of panretinal photocoagulation, preoperative macular detachment and poor preoperative visualacuity were significantly associated with poor final visual acuity aftervitrectomy. A stepwise multiple logistic regression analysis showed thatelevated vitreous levels of IL-8 (p ( 0.0001), macular detachment (p = 0.011) and the absence of panretinal photocoagulation (p = 0.03) were independent predictors for poor visual outcome. Conclusions: Elevated vitreousIL-8 level could either be a marker of ischaemic inflammatory reaction, or it could play a role in deteriorating visual acuity by DR progression or both. Further studies are needed to provide better understanding of IL-8 and inflammation involvement in visual prognosis in PDR.
COBISS.SI-ID: 27754201
Human anterior lens epithelial cells, attached to surgically isolated capsules, were found to contract upon stimulation. The purpose of this study was to characterize these contractions, which create gaps between cells, and to assess the underlying physiological mechanisms and their possible association with cataract formation. METHODS: Lens capsules obtained during cataract surgery were stained with fluorescent dye Fura-2. Its fluorescence, upon excitation at 360 and 380 nm, was imaged to monitor changes in cell morphology and cytosolic free Ca(2+) concentrations ([Ca(2+) ](i) ) in response to pharmacological stimulation by acetylcholine (ACh) and to mechanical stimulation by flow of saline or direct contact. RESULTS: Epithelial cells contracted in approximately a third of preparations when stimulated by either ACh application, fluid movement or direct mechanical contact. Contractions started either before or at best simultaneously with the rise in [Ca(2+) ](i). Contractions also occurred when there was hardly any change in [Ca(2+) ](i) upon application of physiological saline alone. The probability of contractions occurring did not differ significantly among cortical, nuclear and combined cortical + nuclear cataract. CONCLUSIONS: This study provides the evidence that contractions of the anterior lens epithelial cells take place in significant portion of human lens anterior capsule postoperative preparations after non-specific stimulation. Contractions are at least partially independent of changes in [Ca(2+) ](i). They can be mechanically induced, are localized and reversible and have a fast response and did not differ among different types of cataract. Physiological and clinical significance of this phenomenon remains to be elucidated.
COBISS.SI-ID: 2425679