Evaluation of a combined index of optic nerve structure and function for glaucoma diagnosis

<p>Abstract</p> <p>Background</p> <p>The definitive diagnosis of glaucoma is currently based on congruent damage to both optic nerve structure and function. Given widespread quantitative assessment of both structure (imaging) and function (automated perimetry) in glaucoma, it should be possible to combine these quantitative data to diagnose disease. We have therefore defined and tested a new approach to glaucoma diagnosis by combining imaging and visual field data, using the anatomical organization of retinal ganglion cells.</p> <p>Methods</p> <p>Data from 1499 eyes of glaucoma suspects and 895 eyes with glaucoma were identified at a single glaucoma center. Each underwent Heidelberg Retinal Tomograph (HRT) imaging and standard automated perimetry. A new measure combining these two tests, the structure function index (SFI), was defined in 3 steps: 1) calculate the probability that each visual field point is abnormal, 2) calculate the probability of abnormality for each of the six HRT optic disc sectors, and 3) combine those probabilities with the probability that a field point and disc sector are linked by ganglion cell anatomy. The SFI was compared to the HRT and visual field using receiver operating characteristic (ROC) analysis.</p> <p>Results</p> <p>The SFI produced an area under the ROC curve (0.78) that was similar to that for both visual field mean deviation (0.78) and pattern standard deviation (0.80) and larger than that for a normalized measure of HRT rim area (0.66). The cases classified as glaucoma by the various tests were significantly non-overlapping. Based on the distribution of test values in the population with mild disease, the SFI may be better able to stratify this group while still clearly identifying those with severe disease.</p> <p>Conclusions</p> <p>The SFI reflects the traditional clinical diagnosis of glaucoma by combining optic nerve structure and function. In doing so, it identifies a different subset of patients than either visual field testing or optic nerve head imaging alone. Analysis of prospective data will allow us to determine whether the combined index of structure and function can provide an improved standard for glaucoma diagnosis.</p

Bioinformatic and statistical analysis of the optic nerve head in a primate model of ocular hypertension

<p>Abstract</p> <p>Background</p> <p>The nonhuman primate model of glaucomatous optic neuropathy most faithfully reproduces the human disease. We used high-density oligonucleotide arrays to investigate whole genome transcriptional changes occurring at the optic nerve head during primate experimental glaucoma.</p> <p>Results</p> <p>Laser scarification of the trabecular meshwork of cynomolgus macaques produced elevated intraocular pressure that was monitored over time and led to varying degrees of damage in different samples. The macaques were examined clinically before enucleation and the myelinated optic nerves were processed post-mortem to determine the degree of neuronal loss. Global gene expression was examined in dissected optic nerve heads with Affymetrix GeneChip microarrays. We validated a subset of differentially expressed genes using qRT-PCR, immunohistochemistry, and immuno-enriched astrocytes from healthy and glaucomatous human donors. These genes have previously defined roles in axonal outgrowth, immune response, cell motility, neuroprotection, and extracellular matrix remodeling.</p> <p>Conclusion</p> <p>Our findings show that glaucoma is associated with increased expression of genes that mediate axonal outgrowth, immune response, cell motility, neuroprotection, and ECM remodeling. These studies also reveal that, as glaucoma progresses, retinal ganglion cell axons may make a regenerative attempt to restore lost nerve cell contact.</p

Buoyancy-assisted mixed convective flow over backward-facing step in a vertical duct using nanofluids

Laminar mixed convective buoyancy assisting flow through a two-dimensional vertical duct with a backward-facing step using nanofluids as a medium is numerically simulated using finite volume technique. Different types of nanoparticles such as Au, Ag, Al2O3, Cu, CuO, diamond, SiO2 and TiO2 with 5 % volume fraction are used. The wall downstream of the step was maintained at a uniform wall temperature, while the straight wall that forms the other side of the duct was maintained at constant temperature equivalent to the inlet fluid temperature. The walls upstream of the step and the backward-facing step were considered as adiabatic surfaces. The duct has a step height of 4.9 mm and an expansion ratio of 1.942, while the total length in the downstream of the step is 0.5 m. The downstream wall was fixed at uniform wall temperature 0 = ?T= 30 °C, which was higher than the inlet flow temperature. The Reynolds number in the range of 75 = Re = 225 was considered. It is found that a recirculation region was developed straight behind the backward-facing step which appeared between the edge of the step and few millimeters before the corner which connect the step and the downstream wall. In the few millimeters gap between the recirculation region and the downstream wall, a U-turn flow was developed opposite to the recirculation flow which mixed with the unrecirculated flow and traveled along the channel. Two maximum and one minimum peaks in Nusselt number were developed along the heated downstream wall. It is inferred that Au nanofluid has the highest maximum peaks while diamond nanofluid has the highest minimum peak. Nanofluids with a higher Prandtl number have a higher peak of Nusselt numbers after the separation and the recirculation flow disappeared

Major depressive disorders in chronic hemodialysis patients in Nazareth: identification and assessment

Zaher Armaly, Joseph Farah, Adel Jabbour, Bishara Bisharat, Amir Abd-El Qader, Shahira Saba, Maha Zaher, Elia El Haj, Munir Hamzi, Abdalla BowirratThe Nazareth Hospital, Hospital Affiliated with Galilee Medical School-Bar Ilan University, Zefat, IsraelObjective: Depression illnesses are commonly observed in hemodialysis (HD) patients, which can influence the quality of life of end-stage renal disease patients. We evaluate the prevalence and predictive risk factors of depression in the Arab population undergoing HD in Nazareth, Israel.Methods: We conducted a prospective study that included 71 patients in the HD unit with a mean age of 61.9 &amp;plusmn; 14.13 years who had undergone HD and 26 healthy control subjects with a mean age of 59.3 &amp;plusmn; 7.3. Beck&amp;#39;s Depression Inventory and Hamilton Depression Scale assessments were administered. Blood analysis for hematological and biochemical parameters was obtained. Diagnosis was made using the Diagnostic and Statistical Manual of Mental Disorders scale to correlate psychological variables with clinical, hematological, and biochemical parameters. Statistical analysis was carried out using analysis of variance followed by Tukey post-hoc multiple comparison tests.Results: The prevalence of depression was 43.7% in HD patients. Between HD patients and controls, cortisol values were 16.96 &amp;plusmn; 0.5476 and 11.96 &amp;plusmn; 1.116, respectively (P &amp;lt; 0.0001; 95% confidence intervals [CI]: 2.416&amp;ndash;6.825). Between depressed HD patients versus control subjects, cortisol values were 16.48 &amp;plusmn; 0.72 and 11.96 &amp;plusmn; 1.116, respectively (P = 0.0013; 95% CI: 1.878&amp;ndash;7.184). Hematological and biochemical parameters were compared between depressed HD and nondepressed patients, but differences between the two groups were found to be insignificant (P &amp;gt; 0.05).Conclusion: Our HD patients were severely depressed. Studies of glucocorticoid turnover activity such as cortisol, a potent chemical stress hormone, may be used as a model and marker for early diagnosis of depression among HD patients. The strong familial support system in Arabic traditions has failed to decrease depression among these patients.Keywords: Beck Depression Inventory, cortisol, depression, hemodialysi

Corticosteroids and Open-Angle Glaucoma in the Elderly A Population-Based Cohort Study

Background It is largely unknown if corticosteroid-induced open-angle glaucoma (OAG) is an entity that is limited to a few susceptible individuals or whether it contributes significantly to the overall population burden of OAG. Objective The aim of this study was to determine whether there is an association between corticosteroid use and the incidence of OAG in the general elderly population. Methods A prospective population-based cohort study was conducted in a general community setting. 3,939 participants of the Rotterdam Study aged 55 years and older for whom data from ophthalmic examinations at baseline and follow-up were available and who did not have glaucoma at baseline were included (baseline examination from 1991 to 1993; follow-up examinations from 1997 to 1999 and from 2002 to 2006). Ophthalmic examinations, including measurement of the intraocular pressure, assessment of the optic nerve head and perimetry, were performed at baseline and follow-up. The use of corticosteroids was monitored continuously during follow-up. Corticosteroids were stratified into five groups: ophthalmic steroids, inhaled steroids, nasal steroids, oral steroids and steroid ointments. Associations between the use of corticosteroids and incident OAG were assessed using logistic regression models. The study outcome measures were the odds ratios (ORs) of associations between the use of corticosteroids and incident OAG. Results During a mean follow-up of 9.8 years, 108 participants (2.8 %) developed OAG. The median number of steroid prescriptions during follow-up was 2 for ophthalmic, 7 for inhaled, 2 for nasal and 2 for oral steroids, and 3 for steroid ointments. The OR of the use of ophthalmic steroids was 1.04 [95 % confidence interval (CI) 0.66, 1.65; p = 0.86], inhaled steroids 0.79 (95 % CI 0.42, 1.48; p = 0.46), nasal steroids 1.26 (95 % CI 0.74, 2.13; p = 0.40), oral steroids 1.03 (95 % CI 0.65, 1.64; p = 0.89) and steroid ointments 0.70 (95 % CI 0.47, 1.05; p = 0.086). These analyses were adjusted for age, sex, high myopia and family history of glaucoma. The small median numbers of prescriptions made it difficult to evaluate dose-response relationships. Conclusion None of the classes of steroids were associated with the incidence of OAG in this elderly population