ABSTRACT
Purpose: To evaluate diagnostic ability of macular ganglion cell layer–inner plexiform layer (GCL-IPL) for detection of preperimetric glaucoma (PPG) and perimetric glaucoma and comparison with peripapillary RNFL. Methods: Three hundred and thirty seven eyes of 190 patients were enrolled (127 normals, 70 PPG, 140 perimetric glaucoma). Each patient underwent detailed ocular evaluation, standard automated perimetry, and spectral domain optical coherence tomography. Diagnostic abilities of GCL-IPL and RNFL parameters were determined. Data were compared using one-way analysis of variance, Pearson's Chi-square test, and area under the curve (AUC). Results: After adjusting for age, gender, and signal strength, all GCL-IPL and RNFL parameters except mean thickness and disc area differed significantly. Among GCL-IPL thicknesses, inferotemporal had the highest AUC (0.865) for classifying perimetric glaucoma from normals, inferior (0.746) for PPG from normals, and inferotemporal (0.750) for perimetric glaucoma from PPG. When using RNFL, inferior thickness had the highest AUC (0.922) in discriminating POAG from normal, while the same parameter had lower AUC (0.813) in discriminating PPG from normal. The average thickness had maximum AUC (0.775) for discriminating POAG from PPG. For discriminating perimetric glaucoma and normals, inferotemporal GCL-IPL had the highest strength (sensitivity 81.43% and specificity 77.96%), slightly lower than inferior RNFL thickness (sensitivity 87.85% and specificity 84.26%). The same parameters were sensitive in discriminating perimetric glaucoma from PPG (87.14% and 92.85%, respectively). However, their specificities were poor (56.43% both). Conclusion: RNFL had better diagnostic ability, when compared with GCL-IPL for detecting PPG and perimetric glaucoma. However, difference was small and may not be clinically relevant.
ABSTRACT
Purpose: To study macular ganglion cell layer--inner plexiform layer complex (GCL + IPL) in relation to peripapillary retinal nerve fiber layer (RNFL) in glaucomatous eyes with superior or inferior hemifield defects (HD) and to study structural configuration in normal hemifield. Methods: This was an observational cross-sectional study. Data from consecutive 45 superior HD (SHD) and 50 inferior HD (IHD) eyes were analyzed. Each patient underwent detailed ocular examination, standard automated perimetry, and spectral domain optical coherence tomography (SD-OCT). After adjusting for age, gender, and signal strength, area under receiver operating characteristic curve (AUC) was calculated to determine diagnostic ability of GCL + IPL and peripapillary RNFL. Apparently normal hemifield was compared with true normal hemifield. Data were analyzed with SPSS, analysis of variance, t-test, Chi-square test, and receiver operating curve. Results: In the SHD glaucoma group, best parameters for discriminating normal eyes from glaucomatous eyes were inferotemporal GCL + IPL thickness (0.935) and inferior quadrant RNFL thickness (0.971). For IHD glaucoma, average GCL + IPL thickness (0.877) and average RNFL thickness (0.950) had best AUC values. When evaluating apparently normal hemifield in both groups, statistically significant difference was found in inferior GCL + IPL sector (0.865) and inferior quadrant RNFL (0.883) in IHD and superonasal GCL + IPL (0.725) and superior quadrant RNFL (0.842) in SHD groups. Conclusion: SD-OCT may be a useful ancillary diagnostic tool for evaluation of early macular and circumpapillary structural changes in glaucomatous eyes with localized visual field defects. Apparently normal hemifields show structural damage and should be considered in management of glaucoma.
ABSTRACT
Exploitation of microbial wealth, of which almost 95% or more is still unexplored, is a growing need. The taxonomic placements of a new isolate based on phenotypic characteristics are now being supported by information preserved in the 16S rRNA gene. However, the analysis of 16S rDNA sequences retrieved from metagenome, by the available bioinformatics tools, is subject to limitations. In this study, the occurrences of nucleotide features in 16S rDNA sequences have been used to ascertain the taxonomic placement of organisms. The tetra- and penta-nucleotide features were extracted from the training data set of the 16S rDNA sequence, and was subjected to an artifi cial neural network (ANN) based tool known as self-organizing map (SOM), which helped in visualization of unsupervised classifi cation. For selection of signifi cant features, principal component analysis (PCA) or curvilinear component analysis (CCA) was applied. The SOM along with these techniques could discriminate the sample sequences with more than 90% accuracy, highlighting the relevance of features. To ascertain the confi dence level in the developed classifi cation approach, the test data set was specifi cally evaluated for Thiobacillus, with Acidiphilium, Paracocus and Starkeya, which are taxonomically reassigned. The evaluation proved the excellent generalization capability of the developed tool. The topology of genera in SOM supported the conventional chemo-biochemical classifi cation reported in the Bergey manual.
ABSTRACT
Twenty patients with Crohn's disease seen in Jamaica over the past 20 years are reviewed. There were 14 women and 6 men. The mean age at presentation was 37m years, and symptoms were present for a mean of 12 months. Fourteen patients presented with lower abdominal pain, and diarrhoea was present in 11. Lower gastrointestinal bleeding was the presenting feature in 2. The distribution of disease was ileal in 6, and 8 had primary colonic involvement. Three patients had ileocolitis and one perianal disease. One had involvement of the entire small intestine and ascending colon and another had skip lesions involving several areas of the small intestine. Surgical resection was performed in 5 patients. Of the 15 patients treated medically, 6 have remained well while 8 had recurrent episodes of relapse. Crohn's disease in an uncommon disorder in Jamaica but should be considered in patients presenting with inflammatory bowel disease