Motion discrimination of single targets: comparison of preliminary findings in normal subjects and patients with glaucoma

Background: Luminance, global motion and flicker sensitivities are affected in patients with primary open-angle glaucoma. Although no theoretical model has been put forward to explain the observed reduction in sensitivity in this patient group, these findings have often been attributed to diffuse and selective loss of large optic nerve fibres. Methods: Movement processing was investigated using an optical projection system that generates smooth, continuous motion with control of speed, displacement and motion direction. Motion-displacement and direction-discrimination thresholds were measured in eight normal subjects and in three patients with diagnosed glaucoma. At each speed tested, targets were presented for a range of displacements and thresholds were extracted after probit analysis. The measurements were carried out both foveally and at 19° in the periphery and provided the data necessary to develop and optimise a model of motion perception based on multiple time delays for the correlation of signals that map progressively more distant parts of the visual field. Results: Our preliminary findings show that direction discrimination can be at chance level even for large displacements when motion is detected 80% of the time. Model simulations show that specific changes in the spatial sampling interval and the speed of transmission of the motion signals involved can cause the observed reduction in motion sensitivity and direction discrimination in patients with glaucoma. Conclusions: A model for motion detection and direction discrimination of single targets has been proposed to account for the measured functional relationship between motion displacement thresholds and target speed in normal subjects. Tested patients with glaucoma show reduced motion sensitivity and poor discrimination of motion direction. The type of degraded performance observed experimentally in glaucoma patients is also predicted by the model. Such predictions require specific changes in model parameters that may be indicative of changes in the retina caused by the disease.     

Bench-to-bedside review: Rapid molecular diagnostics for bloodstream infection - a new frontier?

ABSTRACT: Among critically ill patients, the diagnosis of bloodstream infection poses a major challenge. Current standard bacterial identification based on blood culture platforms is intrinsically time-consuming and slow. The continuous evolvement of molecular techniques has the potential of providing a faster, more sensitive and direct identification of causative pathogens without prior need for cultivation. This may ultimately impact clinical decision-making and antimicrobial treatment. This review summarises the currently available technologies, their strengths and limitations and the obstacles that have to be overcome in order to develop a satisfactory bedside point-of-care diagnostic tool for detection of bloodstream infection.     

Metabolic response of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) to essential oil of Ajwain and thymol

The effects of Carum copticum essential oil (CC EO) and thymol were assayed against fourth instar of Ephestia kuehniella Zeller by determining insecticidal activities and enzymatic responses. Concentrations of 5.42 and 6.81?μl/ml were obtained as LC₅₀ values for CC EO and thymol, respectively. The activities of esterases, aminotransferases, aldolase, and lactate dehydrogenase significantly decreased in the treated larvae by CC EO and thymol. Significant increases in glutathione S-transferases, γ-glutamyl transferase, and phosphatases were observed after treatment. Results revealed that CC EO and thymol significantly influenced the enzymatic activities of E. kuehniella leading to disruption of survival and metabolic responses.     

Harlequin Ichthyosis: Neonatal Management and Identification of a New ABCA12 Mutation

A case of harlequin ichthyosis with compound heterozygous mutations in ABCA12 was successfully managed with intensive neonatal care and endotracheal intubation and without oral retinoids. The individual's appearance improved dramatically during hospitalization and at discharge resembled congenital ichthyosiform erythroderma.