K-ras oncogene mutation in pterygium.

PurposePterygium is claimed to be a benign proliferation triggered by prolonged exposure to ultraviolet radiation. The frequency of K-ras oncogene mutation, which is among the initial mutations in tumorigenesis, is evaluated in this study.Patients and methodsIn this prospective randomized clinical, trial pterygium tissues and normal conjunctiva tissue specimens are obtained from the superotemporal quadrant of patients who underwent primary pterygium excision with autograft transplantation. DNA extraction from tissues was performed using the QIAamp DNA FFPE tissue kit. A PCR reaction was performed to amplify sequences containing codons 12, 13, and 61 of the K-ras gene in DNA. These PCR products then underwent the 'pyrosequencing' procedure for mutations at these codons.ResultsPterygium and normal conjunctival tissue samples of 25 patients (10 females, 15 males) were evaluated in the study. The mean age of the patients was 54.54±13.13 years. Genetic analysis revealed no K-ras mutations in normal conjunctival tissues, whereas pterygium tissues of the same cases demonstrated mutation at codon 12 in one case and mutations at codon 61 in seven cases, which was statistically significant (P<0.05). The point missense mutations at codon 61 were glutamine to arginine (Glu61Arg CAA>CGA) in four cases and glutamine to leucine (Glu61Leu CAA>CTA) in three cases.ConclusionThe significantly higher frequency of codon 61 mutation of the ras oncogene in primary and bilateral pterygium specimens compared with normal conjunctiva supports the tumoral origin of pterygium, and thus set the stage for research into a targeted therapy for pterygium with better outcomes than surgical excision.

Association of age-related macular degeneration with age-related hearing loss.

OBJECTIVE: To assess the association between age-related macular degeneration and age-related hearing loss in Turkish subjects aged 50 years or older. STUDY DESIGN AND SETTING: Prospective, case-control study within a tertiary university hospital. SUBJECTS AND METHODS: Fifty subjects with age-related macular degeneration and 43 healthy subjects underwent ophthalmological and otolaryngological examination. Statistical analyses were conducted for the poorer eye and ear, comparing age-related hearing loss and pure tone average in the macular degeneration group versus controls. RESULTS: Median pure tone average was significantly poorer in the macular degeneration group (35 dBHL) compared with controls (23 dBHL). In the macular degeneration group, hearing loss was significantly greater in dry type (43 dBHL) than wet type (32 dBHL) cases. There was a significant difference between the prevalence of varying degrees of hearing loss in the macular degeneration versus control groups, being respectively: mild, 50 and 35 per cent; moderate, 20 and 5 per cent; and severe, 6 and 0 per cent. There was a weak, but significant correlation between each patient's visual acuity and pure tone average results (r(s) = -0.37, p < 0.001). CONCLUSION: Age-related hearing loss is more common in patients with age-related macular degeneration. Such patients should be questioned regarding hearing difficulty, and referred to an otolaryngologist if appropriate.

A preliminary trial to determine whether prevention of dark adaptation affects the course of early diabetic retinopathy.

UNLABELLED: This study was designed to determine whether a new form of treatment of diabetic retinopathy (DR) was acceptable to patients and whether reduction in the maximal activity of rods in diabetes could affect the progress of DR. METHODS: In 12 patients, trans-lid retinal illumination of one eye was employed during sleep to prevent the depolarisation of rods and thus reduce their metabolic activity. TECHNIQUES: A headband was used to place a source of chemical light over one eye, with its fellow as a control. MEASUREMENTS: Colour contrast thresholds were measured before and after a period of treatment in treated eyes, and the changes were compared to those in untreated fellow eyes, and areas of 'dark retinal anomalies' (microaneurysms, dot haemorrhages) were measured at the same time points. RESULTS: Patients found this intervention to be acceptable, and no adverse effects were noted. In the majority of cases, and for each outcome measure, the treated eyes improved relative to their fellows. The intervention significantly reduced the tritan thresholds in treated eyes relative to their fellows (P=0.03), and the area of dark retinal anomalies decreased in treated eyes and increased in untreated eyes, with a similar probability. CONCLUSIONS: The study showed that this intervention is safe. Although the study was not powered to study efficacy, the results are promising and consistent with other reports that indicate the retina in DR is suffering from hypoxia; however, further trials should be undertaken.