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Biomedical subjects

C M Dickinson

Publications and source records attributed to C M Dickinson.

27 records · Page 2Linked to original sources
PubMed1985

The influence of preexisting oscillations on the binocular optokinetic response.

Full-field binocular optokinetic responses were examined in patients with congenital nystagmus. If the stimulus moved in the same plane as the congenital nystagmus, a gaze-modulated response was recorded for both idiopathic and albino observers. When the congenital nystagmus was almost totally suppressed, neither a gaze-evoked nor a sawtooth response was seen. For stimulus movements in a plane orthogonal to the congenital nystagmus, normal sawtooth optokinetic responses were exhibited by both groups. Experimental evidence supports the hypothesis that the optokinetic response in the meridian of the spontaneous oscillation has been adapted.

Adult↗
PubMed1985

The influence of nystagmoid oscillation on contrast sensitivity in normal observers.

Normal observers subjected to retinal image motion equivalent to that experienced by congenital nystagmats were found to display a contrast sensitivity function with characteristics similar to those shown by nystagmat observers. The amplitude, frequency and waveform (and hence foveation time) of nystagmic oscillation were varied, with alteration of the waveform producing the most significant effect on the contrast sensitivity function. The pseudocycloid waveform with the longest percentage foveation time per cycle was commensurate with the best visual resolution of medium-to-high spatial frequency targets. For all waveforms the length of the foveation period showed good correlation with visual resolution of the targets.

Adult↗
PubMed1985

Blue light hazard and aniridia.

The fundi of three patients with aniridia were photographed with a 470 nm illuminating light source. No apparent change in contrast was observable throughout the macular region. This would suggest an absence of the macular pigment. The likelihood of aniridics being more susceptible than normal persons to blue light damage is discussed.

Color↗
PubMed1984

Corneal topography of humans with congenital nystagmus.

The refractive status of individuals with congenital nystagmus (albinos and idiopaths) has been examined. Our results indicate that there is a greater than normal incidence of high spectacle astigmatism. This is predominantly with-the-rule and corneal in origin (anterior surface). Partial neutralization by the against-the-rule residual astigmatism is frequent and does not differ significantly from that reported for normal populations. Topographical studies of the anterior corneal surface revealed that there was no statistically significant difference in the mean shape factor values for the albino, idiopath and control populations. The aetiology of the astigmatism is discussed.

Adolescent↗
PubMed1983

Monochromatic fundus photography of human albinos.

The clinical diagnosis of albinism can often be uncertain, particularly when one is confronted with blond patients with congenital nystagmus. Monochromatic fundus photography was carried out on 31 patients with congenital nystagmus to examine three retinal features: the macular pigment, foveal vasculature, and the retinal pigment epithelium. All subjects who were later classified as albinos did not exhibit any signs of macular pigmentation. Our results imply that monochromatic fundus photography can be a useful aid in the diagnosis of albinism.

Albinism↗
PubMed1983

A microassay system for measuring esterase activity and protein concentration in small samples and in high-pressure liquid chromatography eluate fractions.

A microtiter plate spectrophotometric system has been used together with the Bradford, Ellman, and van Asperen assays to measure protein concentration (to 0.5 microgram) and the activities of acetylcholinesterase (to 10(-3) units) and carboxylesterase (to 30 micrograms beta-naphthol reaction product) in small samples such as high-performance liquid chromatographic eluate fractions. For 100-microliter samples, at least 300 Ellman acetylcholinesterase or Bradford protein assays can be conducted and read in less than 30 min, and a like number of van Asperen nonspecific esterase assays (including 1-h incubation) run in less than 90 min. The eluate from a single 20-min high-performance liquid chromatographic run of a biological sample can be collected as up to 300 fractions directly into microtiter plate wells, and the three assays run on all fractions in less than 90 min.

Acetylcholinesterase↗
PubMed1983

Congenital idiopathic nystagmus in identical twins.

Using an infrared recording system we examined the nystagmus waveforms of a pair of monozygotic twin girls and found them to be dissimilar. It is proposed that in view of the common mode of inheritance the differences are a result of environmental influences.

Adolescent↗
PubMedDate not supplied

A review of gagging problems in dentistry: I. Aetiology and classification.

Some people have a pronounced gag reflex that can be a severe limitation to their ability to accept dental care and the clinician's ability to provide it. It can compromise all aspects of dentistry, from diagnostic procedures to active treatment and can be distressing for all concerned. Many techniques have been described that attempt to overcome the problem. Dentists will undoubtedly see patients with gagging problems and knowledge of a variety of management strategies is necessary to aid the delivery of dental care. This first paper looks at the background to gagging problems and their classification and categorization prior to clinical treatment. The second article will look at the clinical assessment of the patient presenting for dental treatment with a history of gagging problems. It will also review methods used to manage patients with gagging reflexes during dental treatment.

Brain↗