Acute application of antioxidants protects against hyperoxia-induced reduction of plasma nitrite concentration.

We investigated the effects of acute intake of antioxidants on hyperoxia-induced oxidative stress, reduction of plasma nitrite and change in arterial stiffness. Twelve healthy males randomly consumed either placebo or an oral antioxidant cocktail (vitamin C, 1000 mg; vitamin E, 600 IU; alpha-lipoic acid, 600 mg). Every therapy was consumed once, a week apart, in a cross-over design, 30 min before the experiment. The volunteers breathed 100% normobaric oxygen between 30th and 60th min of 1-h study protocol. Plasma levels of nitrite, lipid peroxides (LOOH) and vitamin C, arterial stiffness (indicated by augmentation index, AIx) and arterial oxygen (Ptc O2 ) pressure were measured before and after hyperoxia. Exposure to oxygen caused a similar increase of Ptc O2 in both placebo and antioxidants groups, confirming comparable exposure to hyperoxia (438 ± 100 versus 455 ± 83 mm Hg). Vitamin C was increased in the antioxidants group confirming successful application of antioxidants (69 ± 14 versus 57 ± 15 µm). Hyperoxia resulted in increased AIx and LOOH and decreased nitrite in placebo (-32 ± 11 versus -47 ± 13%, 72 ± 7 versus 62 ± 6 µm H2 O2 and 758 ± 184 versus 920 ± 191 nm, respectively), but not in the antioxidants group (-42 ± 13 versus -50 ± 13%, 64 ± 9 versus 61 ± 8 µm H2 O2 and 847 ± 156 versus 936 ± 201 nm, respectively). The acute intake of selected antioxidants was effective in preserving bioavailabity of ˙NO and vascular function, against hyperoxia-induced oxidative stress.

[Prognostic value of ophthalmic artery color Doppler sonography for progression to glaucoma in vitiligo patients]. / Prognosticka vrijednost ultrazvucnog nalaza arterije oftalmike u bolesnika s vitiligom za nastanak glaukoma.

The aim of this study was to assess the prognostic value, i.e. the role of hemodynamic changes in the ophthalmic artery determined by color Doppler imaging in patients with vitiligo in relation to the occurrence of primary open-angle glaucoma (POAG), and to call attention to the importance of examination of the vascular component in routine examinations of patients by clinical dermatologists and ophthalmologists, due to the possible correlation of vitiligo and ophthalmologic changes indicating POAG. Clinical observations and research have shown that patients treated for vitiligo are often diagnosed with POAG or have confirmed diagnosis in their medical history. These findings motivated the research of the vascular component as a possible correlation between vitiligo and POAG. The vascular component of POAG and its role in the dynamics of glaucoma progression has not been fully explained and is still somewhat controversial, and the resulting ischemic disorders are primarily related to optical nerve damage. During the course of a continuous two-year research started in March 2008 and completed in March 2010, a total of 42 patients with vitiligo were examined in the specialist dermatovenereology unit of the Department of Skin Diseases and Sexually Transmitted Diseases. Following clinical examination and Wood's lamp examination, patients with suspected glaucoma were referred to the glaucoma unit of the Department of Ophthalmology to detect or check the progression of POAG. At the Department of Internal Medicine, Split University Hospital Center, color Doppler imaging of ophthalmic artery was performed in all patients on both eyes to examine its hemodynamics. All study participants underwent complete ophthalmologic examination: visual acuity, fundus of the eye, eye pressure measurement, anterior eye segment biomicroscopy with gonioscopy and visual field. In conclusion, our study showed color Doppler imaging and investigation of vascular parameters in ophthalmic artery to provide an insight into the vascular function in differential analysis and can be determined as a correlation or potential risk factor related to vitiligo and POAG. For this reason, we suggest that patients treated for vitiligo, irrespective of their age, sex, affected area, localization and duration of the disease, should regularly undergo complete ophthalmologic examination with special emphasis on POAG diagnosis. Considering the relatively limited sample and trial period, we can already substantiate and confirm that the correlation is not random. Future research in a larger number of vitiligo and POAG patients should provide definitive answer concerning correlation between the two diseases and lead to final conclusion, along with investigation of other hematologic factors related to blood hypercoagulability in order to reach better understanding of the vascular component function.

Importance of circulating platelet aggregates and haemodynamic changes in ophthalmic artery and progression of visual field loss at pseudoexfoliation glaucoma.

The aim of this work is to examine the role of circulating platelet aggregates (CPA) at pseudoexfoliation glaucoma (PXG), haemodynamic changes in the ophthalmic artery by ultrasonic color Doppler, searching for visual field progression. Vascular component at PXG and its role in VF progression dynamics has not been sufficiently explained, as well as CPA influence to ischaemic events related to optic nerve damage and VF progression. The examination included 80 patients, where of 35 (44%) men average age 68.3 +/- 7.0 and 45 (56%) women average age 65.7 +/- 7.0 (t = 1.66; p = 0.101). Forthy of them suffered from primary open angle glaucoma (POAG) as a control group (healthy), and 40 from pseudoexfoliative glaucoma (PXG) as an experimental group. All the examinees underwent complete ophthalmological examination: visual acuity, ocular fundus, intraocular pressure measured, anterior eye segment biomicroscopy with gonioscopy performed. Also VF examination was performed three times at 6 months intervals. Laboratory testing of CPA proportion values was performed by means of Wu an Hoak method and ultrasonic measurement of blood perfusion in the carotid tree, particularly concerning ophthalmic artery by means of color Doppler. Obtained decreased values of CPA proportion resulted in hypercoagulability of blood in PXG group. At PXG were also found increased blood flow resistivity indexes in ophthalmic artery (RI AO) and internal carotid artery (RI ACI), resulting with ischemia and hypoxia and finally progression of the visual filed damage. In conclusion, our study shows that examining CPA and ultrasonic monitoring of vascular parameters in ophthalmic artery with color Doppler may be the way of better understanding the vascular role in PXG prognosis.