Changes of anterior chamber architecture induced by laser peripheral iridotomy in acute angle closure crisis.

In acute angle closure crisis (AAC), a laser peripheral iridotomy (LPI) is performed to balance the pressure gradient between anterior and posterior chamber. The hereby induced changes in anterior chamber architecture were analyzed using Scheimpflug photography (SP). SP was performed in eyes with AAC and in fellow eyes (FE) before and after LPI. Intraocular pressure (IOP), anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle width (ACA), and central corneal thickness (CCT) were analyzed. The group consisted of 18 patients (14♀, 4♂; 69 ± 11 years) with unilateral AAC. Mean IOP in AAC eyes decreased from 49.3 ± 2.8 mmHg at presentation to 13.7 ± 1.6 mmHg after LPI (p = 0.001). Mean ACV increased from 48.2 ± 3.6 to 60.6 ± 2.4 mm(3) in AAC eyes (p < 0.001) and from 60.4 ± 4.6 to 74.1 ± 3.7 mm(3) in the FE (p < 0.001). Mean ACD increased from 1.27 ± 0.08 to 1.44 ± 0.06 mm (p = 0.01) in AAC eyes and decreased in FE from 1.72 ± 0.08 to 1.59 ± 0.04 mm (p = 0.5). Mean ACA increased from 16.8 ± 1.6 to 20.5 ± 1.5° in AAC eyes (p = 0.01) and from 18.5 ± 1.4 to 22.6 ± 1.5° in the FE (p = 0.01). Mean CCT did not change significantly in both groups after LPI (AAC p = 0.09; FE p = 0.9) but a statistically significant difference between the two groups was detectable before LPI (p = 0.04) which disappeared thereafter (p = 0.14). Using Scheimpflug photography, a significant difference of ACV, ACD, and ACA can be detected after LPI in eyes suffering from acute angle closure crisis which demonstrates the effectiveness of LPI.

[Scheimpflug photography of acute angle closure]. / Scheimpflug-Fotografie bei akutem Winkelblock.

PURPOSE: In acute angle-closure glaucoma a laser iridotomy (IO) is performed to balance the intraocular pressure between the anterior and posterior chambers. The changes induced in the anterior chamber architecture were analyzed using Scheimpflug photography. MATERIAL AND METHODS: Scheimpflug photography was performed in eyes with acute angle closure and in the contralateral eyes before and after IO. RESULTS: In a group of 10 patients (8♀, 2♂, average age71.2 ± 5.3 years) 10 eyes with acute angle closure and 10 contralateral eyes were analyzed. The anterior chamber depth, central corneal thickness and anterior chamber angle did not change significantly after IO. The mean anterior chamber volume showed a statistically significant increase in the 10 eyes with acute angle closure and in the 10 contralateral eyes. CONCLUSION: Anterior chamber volume increases due to IO but not anterior chamber depth, central corneal thickness and anterior chamber angle in eyes with acute angle closure.

Initiation of apoptosis by photodynamic therapy using a novel positively charged and water-soluble near infra-red photosensitizer and white light irradiation.

Our aim was to investigate the photophysical and photodynamic properties of a new, water-soluble positively charged and chemically stable photosensitizer: tetrahydroporphyrin tetratosylat (THPTS). Absorption, fluorescence and (1)H NMR spectra and the intracellular distribution of THPTS were measured. The apoptosis in choroidal melanoma cells was measured using cell death detection ELISA and caspase-8 activity assay. THPTS-PDT efficiency was studied in Balb/c mice bearing C26 colon carcinoma. Subcutaneously located tumors were irradiated with a white light source at a fluence rate of 100 mW/cm(2). THPTS was administrated 3 h before illumination. The tumoricidal effect was examined 24 h after THPTS-PDT by vital staining with 0.4-ml 1% Evans blue solution, intraperitoneally injected to each mouse. THPTS showed a strong absorption band at 760 nm. Its purity, measured by (1)H NMR, is better than 99%. At 24-h incubation period, CLSM revealed THPTS fluorescence in mitochondria and cell nucleus. THPTS possesses no toxic effect in preincubated CM cells without irradiation, and THPTS-PDT causes efficient apoptosis. THPTS-PDT using white light irradiation at a dose of 480 J/cm(2) caused necrosis with a depth of 8 mm in subcutaneously located C26 colon carcinoma in Balb/c-mice. In accordance with the present results, the THPTS seems to be of interest for further in vivo investigations with broad-band white light sources.

Hypoxia: modulation of endothelial cell proliferation by soluble factors released by retinal cells.

A devastating complication of ischemic retinopathies is retinal neovascularization. We studied the impact on retinal endothelial cell proliferation of soluble factors released from cultured retinal glial (Müller) cells and from retinal explant cultures. Hypoxia strongly stimulated VEGF release by all types of cultures but endothelial cell growth was not further increased by the corresponding conditioned media if compared to supernatants obtained under normoxia. When the final concentration of the hypoxia-conditioned media was adjusted to the VEGF level of normoxia-conditioned media, they even inhibited endothelial cell proliferation. Inhibition may be exerted by TGF-beta 2 but TGF-beta 2 mRNA and protein expression in Müller cells were found to be down-regulated under hypoxia. We conclude that retinal endothelial cell proliferation is controlled by the balance of the amount and/or efficacy of several stimulatory and inhibitory factors.