Hyoe Ishikawa

A new quality assessment parameter for optical coherence tomography

Aim: To create a new, automated method of evaluating the quality of optical coherence tomography (OCT) images and to compare its image quality discriminating ability with the quality assessment parameters signal to noise ratio (SNR) and signal strength (SS). Methods: A new OCT image quality assessment parameter, quality index (QI), was created. OCT images (linear macular scan, peripapillary circular scan, and optic nerve head scan) were analysed using the latest StratusOCT system. SNR and SS were collected for each image. QI was calculated based on image histogram information using a software program of our own design. To evaluate the performance of these parameters, the results were compared with subjective three level grading (excellent, acceptable, and poor) performed by three OCT experts. Results: 63 images of 21 subjects (seven each for normal, early/moderate, and advanced glaucoma) were enrolled in this study. Subjects were selected in a consecutive and retrospective fashion from our OCT imaging database. There were significant differences in SNR, SS, and QI between excellent and poor images (p = 0.04, p = 0.002, and p<0.001, respectively, Wilcoxon test) and between acceptable and poor images (p = 0.02, p<0.001, and p<0.001, respectively). Only QI showed significant difference between excellent and acceptable images (p = 0.001). Areas under the receiver operating characteristics (ROC) curve for discrimination of poor from excellent/acceptable images were 0.68 (SNR), 0.89 (IQP), and 0.99 (QI). Conclusion: A quality index such as QI may permit automated objective and quantitative assessment of OCT image quality that performs similarly to an expert human observer.

Focal and Segmental Glomerulosclerosis in Preeclamptic Patients with Nephrotic Syndrome

Etiology and pathogenesis of focal and segmental glomerulosclerosis (FSGS) in patients with toxemia of pregnancy remain controversial. We examined 15 preeclamptic patients presenting with nephrotic syndrome. None of the patients had urinary abnormalities and hypertension before pregnancy. Clinically, proteinuria first developed during pregnancy and disappeared completely in all but one patient lost to follow-up after 1-30 months from delivery. Renal dysfunction, hypertension and edema rapidly resolved in the postpartum period. None of the patients had a progressive clinical course. Renal biopsy specimens obtained postpartum revealed typical features of preeclamptic nephropathy. In addition, findings compatible with FSGS were observed in 13 patients including 4 in which such lesions were unearthed by additional serial sectioning. These results indicate that FSGS may not only be induced by preeclampsia but also be one of the representative glomerular changes in preeclamptic patients with nephrotic syndrome. A favorable clinical course ensues in a manner similar to that of patients with the garden - variety of preeclampsia.

Induction of Interleukin 6 Synthesis in Mouse Glomeruli and Cultured Mesangial Cells

Interleukin 6 (IL-6) is an autocrine growth factor of cultured mesangial cells (MC) and intraglomerular IL-6 production is suggested to be closely associated with the pathogenesis of human mesangial proliferative glomerulonephritis (mesPGN). In this study, to elucidate the mechanisms regulating the intraglomerular production of IL-6, we examined what kinds of stimuli are significant in the induction of IL-6 synthesis in vitro and in vivo. Incubation of cultured mesangial cells with interleukin 1 (IL-1) or bacterial lipopolysaccharide (LPS) induced significant IL-6 production, and intravenous injection of IL-1 or LPS into normal BALB/c mice induced significant intraglomerular IL-6 mRNA expression. Furthermore, we indicated in this study that IL-6 mRNA expression was augmented in the glomeruli of mice with immune complex-mediated glomerulonephritis.

Heidelberg Retina Tomograph 3 machine learning classifiers for glaucoma detection

Aims: To assess performance of classifiers trained on Heidelberg Retina Tomograph 3 (HRT3) parameters for discriminating between healthy and glaucomatous eyes. Methods: Classifiers were trained using HRT3 parameters from 60 healthy subjects and 140 glaucomatous subjects. The classifiers were trained on all 95 variables and smaller sets created with backward elimination. Seven types of classifiers, including Support Vector Machines with radial basis (SVM-radial), and Recursive Partitioning and Regression Trees (RPART), were trained on the parameters. The area under the ROC curve (AUC) was calculated for classifiers, individual parameters and HRT3 glaucoma probability scores (GPS). Classifier AUCs and leave-one-out accuracy were compared with the highest individual parameter and GPS AUCs and accuracies. Results: The highest AUC and accuracy for an individual parameter were 0.848 and 0.79, for vertical cup/disc ratio (vC/D). For GPS, global GPS performed best with AUC 0.829 and accuracy 0.78. SVM-radial with all parameters showed significant improvement over global GPS and vC/D with AUC 0.916 and accuracy 0.85. RPART with all parameters provided significant improvement over global GPS with AUC 0.899 and significant improvement over global GPS and vC/D with accuracy 0.875. Conclusions: Machine learning classifiers of HRT3 data provide significant enhancement over current methods for detection of glaucoma.

Sources of longitudinal variability in optical coherence tomography nerve-fibre layer measurements

Aims: The purpose of this study was to compare the day-to-day reproducibility of optical coherence tomography (OCT; StratusOCT, Carl Zeiss Meditec, Dublin, CA) measurements of retinal nerve-fibre layer (RNFL) measurements at time points 1 year apart. Methods: One eye in each of 11 healthy subjects was examined using the StratusOCT fast RNFL scan protocol. Three fast RNFL scans with signal strength ⩾7 were obtained on each of 3 days within a month. This protocol was repeated after 12 months. A linear mixed effects model fitted to the nested data was used to compute the variance components. Results: The square root of the variance component that was attributed to the differences between subjects was 7.17 μm in 2005 and 7.28 μm in 2006. The square roots of the variance component due to differences between days within a single subject were 1.95 μm and 1.50 μm, respectively, and for within day within a single subject were 2.51 μm and 2.55 μm, respectively. There were no statistically significant differences for any variance component between the two testing occasions. Conclusions: Measurement error variance remains similar from year to year. Day and scan variance component values obtained in a cohort study may be safely applied for prediction of long-term reproducibility.

Clinical Evaluation of Taurine in Congestive Heart Failure—A Double-Blind Comparative Study Using CoQ10 as a Control Drug

Congestive heart failure is a clinical syndrome characterized by symptoms of dyspnea, fatigue, and edema that most commonly result from pathophysiological events following a severe insult to the left ventricle. In recent years, a new therapeutic approach based on the pathophysiology of congestive heart failure has been established. A single agent or combination therapy with cardiac glycosides and diuretics has proven to be effective in the treatment of congestive heart failure. However, in cases of refractory cardiac failure that resist these conventional drugs, vasodilators, sympathomimetics, and myocardial metabolism activators are used in combination therapy.

Glomerular tuft ballooning in mitomycin-C-induced renal impairment.

Severe ballooning of the glomerular tufts was observed in a 65-year-old man who was treated with mitomycin C (MMC) and had typical MMC-induced renal lesions. He developed renal failure and severe anaemia 6 months after initiation of chemotherapy. Ballooned tufts were caused by enormous expansion of the sub-endothelial space simultaneously associated with mesangiolysis. Glomerular cysts, described in a variety of disorders including thrombotic microangiopathy and diabetes mellitus, are derived from cystically dilated and united capillary luminae secondary to mesangiolysis. The morphogenesis of this unusual lesion when induced by MMC differs from that of the glomerular cysts previously reported.

A MORPHOLOGICAL STUDY OF THE LEFT BUNDLE BRANCH IN THE NORMAL HUMAN HEART

To clarify the distribution pattern of the left bundle branch (LBB) in the human heart, the AV conduction system was studied in 13 autopsied hearts obtained from subjects aged 50 to 80 years. Vertical serial sections (7 μm) of the bundle of His and LBB were prepared and every 20th section was stained alternately with hematoxylin‐eosin (HE) or by the elastica van Gieson (EVG) method and examined by light microscopy. Reconstruction was performed using a two‐dimensional system in order to histologically differentiate the bundle cells from Purkinje cells. The LBB bifurcated into the anterior and posterior radiations and the cells in the septal portion were almost all Purkinje cells except in two cases showing a septal branch between the two radiations. The LBB usually branched widely from the bundle of His. An extremely anterior fascicle of the LBB was found in all cases. The distribution of the LBB at the top of the ventricular septum was divided into network and continuous types. Purkinje cells were present on both the atrial and apical sides of the two main radiations. It was suggested that these findings resulted from the fact that we morphologically differentiated the bundle cells from Purkinje cells by light microscopy.

Optical coherence tomography algorithm failure to detect nerve fibre layer defects: report of two cases

Glaucomatous damage typically causes retinal ganglion cell and retinal nerve fibre layer (RNFL) loss that can occur diffusely and focally. Optical coherence tomography (OCT) is a non-invasive, non-contact technology that allows cross-sectional high-resolution in vivo imaging of intraretinal layers. Since structural abnormalities may precede functional abnormalities, it might be expected that an OCT RNFL abnormality would be observed when glaucomatous visual field (VF) loss is present. We report two patients who demonstrated clinically evident focal RNFL defects with corresponding VF loss that failed to be recognised as outside normal limits by OCT analysis. The first subject had normal-tension glaucoma with a best-corrected visual acuity (BCVA) of 20/25 in the right eye and marked optic nerve head (ONH) cupping, inferior disc haemorrhage and inferotemporal RNFL wedge defect (fig 1A). VF showed a superior nasal step with an early arcuate scotoma (fig 1B). The OCT RNFL thickness profile (StratusOCT; Carl Zeiss Meditec, Dublin, California) revealed a narrow depression into the abnormal zone (red colour) in the inferotemporal region and borderline depression (yellow) in the superior and superonasal regions. The OCT demonstrated borderline thin superior sectors on clock-hour analysis when compared with the OCT normative database but failed to demonstrate thinner than normal RNFL in the inferotemporal sectors (fig 1C). The cross-sectional scans showed an overt narrowing of the RNFL that was markedly underestimated by the RNFL edge detection analysis by failing to follow the surface (fig 1D). Figure 1 Red-free photograph …

Anti-nuclear RNP antibodies in two sisters

Two sisters with clinical elements of mixed connective tissue disease were found to have anti‐nuclear RNP (nRNP) antibodies. These antibodies were not found in the six other family members examined. The sisters had inherited an identical HLA haplotype A2‐BW61CW3‐DR1 from their mother who had had Raynauds phenomenon for several years. Analysis of peripheral lymphocyte subsets in the patients and their immediate relatives showed decreased OKT‐4‐positive cells in one of the patients and increased OKT‐8‐positive cells in both patients, their father and their brother, resulting in lower OKT 4/OKT 8 ratios in these members of the family. This is the third description of the familial occurrence of anti‐nRNP antibodies and it adds further evidence for the implication of genetic factors in the development of anti‐nRNP antibodies.