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Biomedical subjects

D J Faulkner

Publications and source records attributed to D J Faulkner.

At least 73 records · Page 4Linked to original sources
PubMed1983

Visual pigment levels in retinitis pigmentosa.

A broad-field imaging fundus reflectometer was used to determine the levels of visual pigment and their relationship to rod-mediated sensitivity in 3 patients with autosomal dominantly inherited retinitis pigmentosa. In each case the loss of sensitivity could be accounted for wholly by the decreased probability of light absorption by the rod photoreceptors resulting from the decreased levels of rhodopsin they contained. In contrast, in a subject whose night blindness was due to vitamin A deficiency, the large sensitivity loss was accompanied by a relatively small reduction in the rhodopsin level.

Female↗
PubMed1981

X-linked retinitis pigmentosa: reduced rod flicker sensitivity in heterozygous females.

A flicker sensitivity test based on measuring modulation thresholds for light varying sinusoidally with time around two mean scotopic luminances was performed on 21 female patients heterozygous for X-linked retinitis pigmentosa and 22 normal observers. The patients required, on average, 1.5 times the normal modulation to detect flicker over the whole frequency range where thresholds could be measured. The results suggest that the rod system of heterozygotes exhibits a reduced signal-to-noise ratio compared with normal but that the dominant time delays in the signaling process are not significantly altered.

Female↗
PubMed1977

Antibiotic metabolites from a marine pseudomonad.

An antibiotic-producing pseudomonad was isolated from a seawater sample from a La Jolla, Calif., tidepool. The pseudomonad produces two novel antibacterial compounds, 2-n-pentyl-4-quinolinol and 2-n-heptyl-4-quinolinol. It also synthesizes indole-3-carboxaldehyde, 6-bromoindole-3-carboxaldehyde, and the known antibiotic p-hydroxybenzaldehyde. Each of these compounds was identified by analysis of spectral data, and the structures were confirmed by synthesis or comparison with authentic samples.

Anti-Bacterial Agents↗
PubMed1977

The Elidice: new instrument for visual acuity self-screening.

A compact electronic device which enables the user to determine for himself whether his visual acuity reaches a chosen standard has been constructed at a cost of 25 pounds. The instrument provides a test which requires the observer to respond to the orientation of a sequence of red Landolt-Cs and which takes under five minutes to complete. 'Crowding' effects associated with conventional letter charts are avoided and the test does not discriminate against astigmatic observers. One hundred observers were tested on both the new instrument (the Elidice) and a standard Snellen chart under clinical conditions. The overall agreement between the two tests was 87.8%, with the Elidice having an over-referral level of 10-7% and an under-referral level of 1-5% as compared with the letter chart. This makes the Elidice particularly suitable for the regular screening of laser users for reduced visual acuity due to macular damage.

Humans↗