Optical coherence tomography of macular crystalline opacities associated with chronic retinal detachment.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
N Narendran
Publications and source records attributed to N Narendran.
Analysis of the EFEMP1 gene in individuals and families with early onset drusen.
AIMS: Age-related macular degeneration (AMD) is considered a complex genetic disease, although the genetic influences are not yet fully understood. Genetic analysis is hampered by the late onset of disease and the difficulty in obtaining multigenerational families. To investigate this problem further we studied our population of early onset drusen cases. The Arg345Trp mutation on exon 10 of the EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) gene causes two clinical phenotypes of early onset drusen (Doyne honeycomb retinal dystrophy and Malattia Leventinese), yet does not appear to be involved in other early onset drusen phenotypes or typical AMD. We wished to ascertain the involvement of the EFEMP1 gene in our population of sporadic and familial subjects presenting with early onset drusen and their affected relatives. METHODS: Individuals presenting with drusen/end-stage maculopathy at 60 years or under were identified from retinal clinics in Melbourne. All available first- and second-degree relatives were also examined. In all, 116 ethnically matched controls were collected from the same community for comparison. RESULTS: Single stranded conformational polymorphism (SSCP) analysis and subsequent sequencing revealed four previously described and three novel sequence variations. Most occurred at similar frequencies in the case and control populations and were not thought to be disease associated. CONCLUSION: The term early onset drusen encompasses a wide range of phenotypes and our findings indicate that it is likely that more than one gene is involved in its causation. It is essential that these clinical phenotypes are well described and categorised to allow greater possibility of success in the search for other disease genes.
Adult↗
Fiber optic pressure sensor for biomedical applications.
In vivo measurement of blood pressure is critical in many settings, including patient care, medical research, and control of cardiovascular assist and replacement devices. This article describes a pressure sensor based on fiber optic, white light interferometry. An optical interference filter formed between the end face of an optical fiber and the sensing diaphragm selectively reflects a wavelength component. A low cost, thin film optical wedge interferometer placed at the output end detects the wavelength of the reflected signal, which represents a unique cavity length of the interference filter directly related to the diaphragm deflection and, therefore, pressure. Several key features of this sensing scheme include low drift, high accuracy, and insensitivity to light loss factors along the length of the optical fiber. This fiber optic pressure sensor promises significant advances as a medical monitoring tool, a research instrument, and a component of cardiovascular assist and replacement devices. A prototype pressure gauge has been built, and the feasibility of the optical approach verified. Experimental results of the prototype gauge for resolution, repeatability, and drift and a preliminary design for a high resolution, low drift, miniature fiber optic pressure probe are presented herein.
Biomechanical Phenomena↗