Objective-Several neurologic disorders are treated with deep brain stimulation; however, the mechanism underlying its ability to abolish oscillatory phenomena associated with diseases as diverse as Parkinson's and epilepsy remain largely unknown. In this study we sought to investigate the role of specific neurotransmitters in deep brain stimulation (DBS) and determine the role of non-neuronal cells in its mechanism of action.Methods-We used the ferret thalamic slice preparation in vitro, which exhibits spontaneous spindle oscillations, in order to determine the effect of high-frequency stimulation on neurotransmitter release. We then performed experiments using an in vitro astrocyte culture to investigate the role of glial transmitter release in HFS-mediated abolishment of spindle oscillations.Results-In this series of experiments we demonstrated that glutamate and adenosine release in ferret slices was able to abolish spontaneous spindle oscillations. The glutamate release was still evoked in the presence of the Na + channel blocker tetrodotoxin (TTX), but was eliminated with the vesicular H + -ATPase inhibitor, bafilomycin, and the calcium chelator, BAPTA-AM. Furthermore, electrical stimulation of purified primary astrocytic cultures was able to evoke intracellular calcium transients and glutamate release, and bath application of BAPTA-AM inhibited glutamate release in this setting.Conclusion-These results suggest that vesicular astrocytic neurotransmitter release may be an important mechanism by which DBS is able to achieve clinical benefits.

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Both narrow band imaging (NBI) and autofluorescence imaging (AFI) are new techniques for the assessment of lung cancer. The major aim of this study was to investigate whether the combination of these two techniques improve sensitivity and specificity in the assessment of lung cancer extension. The study prospectively evaluated 118 patients with suspected lung cancer. All of the patients were examined using EVIS LUCERA SPECTRUM videobronchoscopy system. The narrow band imaging preceded autofluorescence imaging examination. In every patient, at least 1 but no more than 4 biopsies were taken from places visualized as pathologic, surrounding primary tumor, and at least 1 biopsy from places that appeared visually normal. Sensitivity, specificity, positive, and negative predictive value for autofluorescence imaging in the assessment of tumor extension were 89.2, 77.8, 87, and 81%, respectively. Sensitivity, specificity, positive, and negative predictive value for narrow band imaging were 90.4, 82.4, 91.8, and 79.7%, respectively. Corresponding values for combination of techniques were 93.7, 86.9, 94.5, and 85.1%. Combination of techniques significantly improves sensitivity (P = 0.034) with borderline effect on specificity (P = 0.056) of autofluorescence imaging. There was no significant improvement for sensitivity and specificity of NBI alone. The combination of techniques shows significantly better sensitivity and specificity in the assessment of lung cancer extension when compared to white light videobronchoscopy alone, but improvement is not so convincing when compared to the each technique alone.

Aim To measure diameter of foveal avascular zone (FAZ), FAZ area, and vessel density using Optical Coherence Tomography Angiography (OCT-A) in patients with normal tension glaucoma (NTG) and to establish the possible role of OCT-A in diagnosis and follow-up of patients with NTG. Methods Twenty-one eyes of 21 patients with NTG and 30 eyes of 30 healthy subjects underwent complete ophthalmic examination as well as OCT-A on ZEISS AngioPlex. 3 × 3 macula scans were used to measure vertical, horizontal, and maximum diameter of FAZ by two graders. Mean values and interobserver variability were analyzed. Image J was used for analysis of FAZ area and vessel density. Results Mean vertical diameter (t = 5.58, p < 0.001), horizontal diameter (t = 3.59, p < 0.001), maximum diameter (t = 5.94, p < 0.001), and FAZ area (t = 5.76, p < 0.001) were statistically significantly enlarged in the NTG group compared to those in the control group. Vessel density (t = −5.80, p < 0.001) was statistically significantly decreased in the NTG group compared to that in the control group. Conclusion OCT-A could have an important role in the future in diagnosis of patients with NTG. In patients with NTG, there is larger FAZ area, while the vessel density is reduced in comparison to the control group.

Introduction: The aim of the paper was to analyze the changes in the macular ganglion cell layer and inner plexiform layer (GCL-IPL) thickness in patients with Parkinson's disease. Material and methods: The study enrolled 46 patients with established diagnosis of Parkinson's disease and 46 healthy subjects. Both groups were age- and gender-matched. An OCT protocol, namely standardized Ganglion Cell Analysis algorithm was used to measure the thickness of the macular GCL-IPL layer. The average, minimum, and six sectoral (superotemporal, superior, superonasal, inferonasal, inferior, inferotemporal) GCL-IPL thicknesses were measured from the elliptical annulus centered on the fovea. Results: The mean value of the clinical severity of Parkinson's disease was between 2 and 3, according to the Hoehn and Yahr scale. Statistically significant thinning of the GCL-IPL layer was registered in average and minimum GCL-IPL thickness, as well as in the sectoral layer thicknesses in patients with Parkinson's disease in comparison to the controls. There was no correlation between structural changes in the retina and disease duration or severity. A statistically significant difference in thickness between the different stages of the disease was registered only in the inferior sector. Conclusions: Parkinson's disease is accompanied by thinning of the GCL-IPL complex of macula even in the earliest stages. This may indicate a possible retinal dopaminergic neurodegeneration. There is no correlation between duration or severity of Parkinson's disease with thinning of the GCL-IPL complex. .

Sarcoidosis is a chronic systemic autoimmune disease which belongs to a group of systemic granulomatous diseases. It can be confirmed through characteristic systemic and ocular manifestations and histological findings. Biopsy is the golden standard for diagnosing sarcoidosis. Ocular sarcoidosis can be confirmed, probable, or possible. Over a two-year period, ocular manifestations were studied on a sample of 52 patients, each followed for four months and diagnosed with some form of systemic sarcoidosis. Most frequent systemic manifestations in patients with ocular sarcoidosis were pulmonary, skin, glandular, and systemic generalized sarcoidosis. The disease was diagnosed four times more frequently in females than males (42:10, respectively; p < 0.05). Most frequent, and statistically significant, manifestation of ocular sarcoidosis is anterior uveitis (64.61%; p < 0.01). Macular edema and periphlebitis associated with periarteritis were frequent, and statistically significant (43.90% and 29.26%, respectively; p < 0.05). Overall, with regards to gender and location (right eye; left eye), visual acuity was >0.5 and of statistical significance (76.92%; p < 0.01). The most common therapy consisted of systemic corticosteroids (26.67%) and/or a combination of corticosteroids and immunosuppressive drugs (23.33%). In 16 eyes treated with repeated doses of sub-Tenon's injections, both initial and control visual acuity correlated with average thickness. There was positive correlation between several optical coherence tomography findings before and after treatment.

Aim: To compare ganglion cell (GCL) and inner plexiform layer (IPL) thickness in patients at different stages of primary open-angle glaucoma (POAG), determine their sensitivity and specificity values, and correlate thickness values with mean deviations (MD). Methods: This prospective, cross- sectional study was conducted in a group of patients with confirmed POAG who were compared to an age- and gender-matched control group. Glaucomatous damage was classified according to the Hodapp-Parrish-Anderson scale: glaucoma stage 1 (early), glaucoma stage 2 (moderate), and glaucoma stage 3 (severe). The average, minimum, and all 6 sectoral (superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal) GCL + IPL thicknesses were measured and compared between groups. Results: The average GCL + IPL thickness of 154 eyes of 93 patients in glaucoma stages 1, 2, 3, and 94 eyes of 47 persons in the control group were 76.79 ± 8.05, 65.90 ± 7.92, 57.38 ± 10.00, and 86.01 ± 3.68 μm, respectively. There were statistically significant differences in the average, minimum, and all 6 sectoral GCL + IPL values among the groups. The areas under the receiver operating characteristic curve for average and minimum GCL + IPL thickness values were 0.93 and 0.94, respectively, sensitivity 91.5 and 88.3%, and specificity 98.9 and 100%, respectively. Both thickness values showed significant correlations with MD. Each micrometer decrease in the average GCL + IPL thickness was associated with a 0.54-dB loss in MD. Conclusion: GCL + IPL layer thickness is a highly specific and sensitive parameter in differentiating glaucomatous from healthy eyes showing progressive damage as glaucoma worsens. Loss of this layer is highly correlated with overall loss of visual field sensitivity.

Abstract:Oxidative stress and the production of reactive oxygen species are known to play a major role in neuronal cell damage, but the exact mechanisms responsible for neuronal injury and death remain uncertain. In the present study, we examined the effects of oxidative stress on spontaneous spike activity and depolarizing outward potassium current by exposing the Retzius neurons of the leech to cumene hydroperoxide (CHP) and hydrogen peroxide (H 2 O 2 ), the oxidants commonly used to examine oxidative mechanisms mediating cell death. We observed that relatively low concentrations of CHP (0.25, 1, and 1.5 mM) led to a marked prolongation of spontaneous repetitive activity. The prolonged action potentials showed an initial, spike-like depolarization followed by a plateau phase. In contrast, H 2 O 2 at the same and much higher concentrations (0.25 to 5 mM) did not significantly change the duration of spontaneous spike potentials of leech Retzius nerve cells (LRNCs). In the voltage clamp experiments, calcium-activated outward potassium currents, needed for the repolarization of the action potential, were suppressed with CHP, but not with H 2 O 2 . The present findings indicate that CHP is a more potent oxidant and neurotoxin than H 2 O 2 and that the effect of CHP on the electrophysiological properties of LRNCs may be due to the inhibition of the potassium channels.