Comparison of horizontal corneal diameter measurements using Galilei,EyeSys and Orbscan II systems

Background: White‐to‐white corneal measurement is used frequently in cataract and refractive surgery as well as in diagnosing various corneal diseases and monitoring congenital glaucoma. In this article, we determine agreement in horizontal corneal diameter measurements in normal eyes among the Galilei V4.01, the EyeSys and the Orbscan IIz. Methods: In this prospective study, 37 consecutive volunteers were enrolled. All 74 eyes were measured with all three devices. Galilei, EyeSys and Orbscan II measurements were compared with one another. In addition, the data from the right and left eyes were compared for each device. Results: The mean horizontal corneal diameter measurements with the Galilei, the EyeSys and the Orbscan II were 12.01 ± 0.61 mm, 12.09 ± 0.87 mm and 11.67 ± 0.29 mm, respectively. The difference between the Galilei and EyeSys systems was not statistically significant (p = 0.76), however, the Orbscan II showed smaller measurements (p < 0.001). The best 95% limits of agreement between devices were for the Galilei and the Orbscan II (‐0.72, 1.48; r = 0.4, p < 0.01). The best 95% limits of agreement between two eyes for each device were found with the Orbscan II (‐0.15, 0.17; r = 0.996, p < 0.01). There was no correlation between measurements of right and left eyes for the Galilei or the EyeSys (r = 0.274, p = 0.176 and r = 0.31, p = 0.065, respectively). Conclusions: These results suggest that measurements made with the Orbscan II are smaller than those obtained with the EyeSys Corneal Analysis system and the Galilei. Among the three devices, the Galilei and the Orbscan II showed the best agreement, however, it is inadvisable to use the three devices interchangeably in every clinical situation.     

Cognitive decline tracks motor progression and not disease duration in Parkinson patients

We performed an analysis of prospectively-acquired cross sectional data on 106 Parkinson disease (PD) patients who underwent comprehensive neuropsychological testing and the Unified Parkinson Disease Rating Scale (UPDRS) motor scale. A significant correlation between the UPDRS motor and neuropsychological tests in all cognitive domains except for general intelligence and visuo-spatial function was seen. In this study, cognitive decline within this PD cohort correlated with motor impairment but not disease duration. Our findings suggest that overall cognitive impairment (except visuospatial dysfunction) may track motor progression in PD more than duration of disease. Longitudinal studies are needed to confirm our results.     

Immunohistochemical study of human rabies

Rabies is a communicable disease that is almost always fatal. In its classic form, rabies is well recognized, but cases presenting with a paralytic illness mimic Landre's Guillain–Barre syndrome and in such cases the diagnosis remains in doubt. This problem is further compounded when the history of dogbite is not forthcoming. At autopsy rabies can be diagnosed by subjecting fresh tissue to virologic investigations or examining formalin‐fixed paraffin‐embedded tissue sections for the presence of characteristic inclusions; that is, the Negri bodies. However, these inclusions are not present in all cases. Hence, the need arises for a better method for diagnosis. The present study utilized immunohistochemistry as a diagnostic tool using both monoclonal and polyclonal antirabies antibodies in 20 cases of rabies encephalomyelitis. The diagnosis of rabies could be confirmed in 17 cases (85%) based on neuropathologic findings alone. In contrast, immunohistochemistry yielded positive results in all cases. Moreover, the amount of rabies viral antigen was much more abundant than could be expected from the histopathologic findings. Thus immunohistochemistry is a rapid, safe, sensitive and specific technique for the diagnosis of rabies.     

The Relationship Between Homocysteine and Genes of Folate-Related Enzymes in Migraine Patients

(Headache 2010;50:99‐168) Background.— It has been suggested that homocysteine (Hcy) and the 5′‐10′‐methylenetetrahydrofolate reductase (MTHFR) C677T variant are implicated in the pathogenesis of migraine. Homocysteine has the potential to damage endothelium and accelerate atherosclerosis. Genetic factors such as the MTHFR C677T polymorphism, and other polymorphisms in folate‐related genes associated with high homocysteine levels, may contribute to increasing this vascular risk. Results.— We recruited 427 migraine patients (199 without aura [MO]; 228 with aura [MA]), and 310 controls in a neurologic clinic. Hcy levels and 6 polymorphisms corresponding to 6 folate‐related genes, including the MTHFR C677T variant, were determined in all migraine participants and in a subset of 155 controls. We found higher sex‐adjusted Hcy levels in MA (mean: 11.02 µM) than MO patients (9.86 µM; P = .005 for the difference). Hcy levels higher than 12.0 µM doubled the risk for MA (OR = 2.145; 95% confidence intervals [CI] = 1.3‐3.4; P = .001), and those higher than 15.0 µM incurred a 6‐fold increase (OR = 5.95; 95% CI = 2.1‐20.0, P < .001). The number of MTHFR 677T alleles was the best genetic predictor of Hcy levels (r² = 0.06; P = 6.2e‐6; corrected for genetic variants analyzed) and this effect remained significant after correction for other confounding factors. Using multi‐dimensionality reduction approaches, we observed significant epigenetic interaction among some of the folate‐related genetic variants to predict higher Hcy levels, and also among higher Hcy levels and folate‐related genetic variants to predict the end‐diagnosis of MA only among migraineurs. In controls, Hcy levels and the number of MTHFR 677T alleles were found to be intermediate between those observed in MA and MO patients. Conclusion.— Our results suggest that MA patients have higher Hcy levels. We also observed complex epigenetic interaction among folate‐related enzymes, sex, and Hcy levels predicting MA phenotype. Nevertheless, genetic factors explained only a minor proportion of the variance for both Hcy plasma levels and for predicting MA phenotype. Determination of MTHFR C677T polymorphisms and Hcy levels may be useful to identify patients with a high risk of suffering from MA.     

Malignant-lesion segmentation using 4D co-occurrence texture analysis applied to dynamic contrast-enhanced magnetic resonance breast image data

PURPOSE: To investigate the use of four-dimensional (4D) co-occurrence-based texture analysis to distinguish between nonmalignant and malignant tissues in dynamic contrast-enhanced (DCE) MR images. MATERIALS AND METHODS: 4D texture analysis was performed on DCE-MRI data sets of breast lesions. A model-free neural network-based classification system assigned each voxel a "nonmalignant" or "malignant" label based on the textural features. The classification results were compared via receiver operating characteristic (ROC) curve analysis with the manual lesion segmentation produced by two radiologists (observers 1 and 2). RESULTS: The mean sensitivity and specificity of the classifier agreed with the mean observer 2 performance when compared with segmentations by observer 1 for a 95% confidence interval, using a two-sided t-test with alpha = 0.05. The results show that an area under the ROC curve (A(z)) of 0.99948, 0.99867, and 0.99957 can be achieved by comparing the classifier vs. observer 1, classifier vs. union of both observers, and classifier vs. intersection of both observers, respectively. CONCLUSION: This study shows that a neural network classifier based on 4D texture analysis inputs can achieve a performance comparable to that achieved by human observers, and that further research in this area is warranted.     

The Effects of Piracetam Upon Visual Event-Related Potentials in Dyslexic Children

Twenty-nine dyslexic children (mean age 10 yrs) were randomly assigned to piracetam (3.3 gr/d) or matching placebo in a 36-week double-Mind study. Event-related potentials (ERPs) were obtained at the end of treatment from a vigilance paradigm which required a response to letter-matches or form-matches. The drug group showed a significant advantage in letter-bits compared with placebo, and a reduced variance in reaction time. The drug increased the amplitude of three factors from a principal components analysis of ERPs, and was interpreted as increasing a processing negativity when stimuli were letters. Effects upon the prestimulus baseline for letter-hits were interpreted as faster termination of a CNV under drug for letter-pairs. Latency of early N100 components were faster under drug, suggesting improved feature analysis. It is concluded that piracetam enhances feature analysis and increases attentional resources among dyslexics when the stimuli are recognized as having linguistic significance.