PubMed Health⌕ Search

Biomedical subjects

J M Gibson

Publications and source records attributed to J M Gibson.

At least 127 records · Page 7Linked to original sources
PubMed1988

On the relation between perceptual priming and recognition memory.

Two experiments evaluated the hypothesis that perceptual fluency is used to infer prior occurrence. Subjects heard (Experiment 1) or saw (Experiment 2) a list of words and then were presented in the same modality with both these and other words twice in succession: first in a more or less impoverished fashion, and then in clear fashion. For the first of these two presentations, the subjects tried to identify the word; for the second, they gave a recognition judgement. As predicted by the perceptual fluency hypothesis, and as has been found in previous research, the recognition judgments were more positive for identified words than for unidentified words. However, degree of impoverishment, by which apparent perceptual fluency was brought under experimental control, did not affect the recognition judgments. The perceptual fluency hypothesis was therefore not supported, and the observed relation between identification and recognition was attributed to an item selection effect.

Adult↗
PubMed1988

Vision and visual acuity in an elderly population.

The data for this paper were collected during a two-year study of the elderly in the market town of Melton Mowbray. The data show that typically, persons aged 75 years and older have poor uncorrected vision (6/36 Snellen acuity), but good corrected acuity, 73.8 per cent gaining 6/12 binocular Snellen acuity or better. Over 88 per cent were able to read N8 typesize or better, under test conditions. Those with low uncorrected vision were the most likely to possess spectacles.

Aged↗
PubMed1988

Refraction and refractive errors in an elderly population.

The data for this paper were collected during a two-year study of the elderly in the market town of Melton Mowbray. The randomly selected subjects, aged 76 years of age and older, were found to be on average +1.33 D hypermetropic and the average cylinder power was 0.82 D. The mean refractive error was found to be +1.5 D with 0.5 negative cylinder at between 85 and 90 degrees. Of all the subjects, 30 per cent had significant anisometropia.

Aged↗
PubMed1988

Heterogeneity of drug-dependent platelet antigens and their antibodies in quinine- and quinidine-induced thrombocytopenia: involvement of glycoproteins Ib, IIb, IIIa, and IX.

The molecular nature of platelet receptors for quinine- and quinidine-dependent antiplatelet antibodies (Q.Ab and Qd.Ab) was studied by immunoblotting. One Q.Ab caused quinine-dependent IgG binding to platelet proteins with molecular weights (mol wts) of 174 Kd and 93 Kd and another to only a 93-Kd protein. A third Q.Ab caused binding to 174-, 140-, 93-, and 57-Kd proteins, while a fourth Q.Ab and a Qd.Ab caused IgG binding to 174- and 18-Kd proteins. Using platelets from patients with Glanzmann's thrombasthenia or Bernard Soulier syndrome and purified GPIIIa, these proteins were shown to be GPIb, GPIIb, GPIIIa, GPIX, and an unidentified 57-Kd protein missing in Bernard Soulier syndrome. Binding to the 93-Kd protein was independent of the PIA1 antigen. Absorption of one Q.Ab with Glanzmann's thrombasthenia platelets revealed different populations of antibodies with different specificities within the one patient. Thus Q.Ab and Qd.Ab are heterogeneous and may be directed toward different epitopes on major platelet glycoproteins.

Antigens, Differentiation↗
PubMed1987

Ocular motor and manual tracking in Parkinson's disease and the effect of treatment.

A quantitative analysis of unpredictable saccadic and smooth pursuit ocular motor and manual tracking was performed in 15 mildly affected, previously untreated subjects suffering from Parkinson's disease and in age-matched normal controls. The patients' ocular saccades were characterised by an increased variability of their latencies and reduced accuracy, with normal velocity profiles apart from saccadic duration. Their smooth pursuit had a decreased velocity gain. Similar abnormalities were found with manual tracking. Clinical improvement with dopaminergic drugs was associated with an improvement of saccadic accuracy and smooth pursuit gain. It is postulated that the ocular motor changes seen in Parkinson's disease are contingent upon functional dopamine levels in the basal ganglia.

Adult↗
PubMed1987

A quantitative comparison of stimulus-response relationships of vibrissa-activated neurons in subnuclei oralis and interpolaris of the rat's trigeminal sensory complex: receptive field properties and threshold distributions.

Electrical activity of single vibrissa-activated neurons was recorded in pars interpolaris and pars oralis of the nucleus of the trigeminal spinal tract of rats. Stimuli consisted of quantitatively controlled deflections of individual mystacial vibrissae. The evoked spike trains were analyzed as point-process time series with a variety of quantitative procedures. Most second-order trigeminal neurons were directionally sensitive. About one-third of interpolaris neurons and over half of oralis neurons responded to axial push of the hair shaft. About half of the neurons of both oralis and interpolaris had receptive fields that included more than one vibrissa. The upper-quartile receptive field size of neurons of interpolaris was about half that of oralis, although the distributions overlapped. In interpolaris, almost one-fifth of the sample discharged in the absence of an intentionally applied stimulus; in oralis, over one-third of the sample displayed background activity. The ranges of angular displacement thresholds of both samples exceeded three orders of magnitude. The distributions differed quantitatively. They were, nevertheless, similar in shape, and exhibited considerable overlap. The median threshold of oralis neurons was about half that of interpolaris neurons, and about one-fifth that of first-order neurons. About one-fourth of the second-order neurons exhibited a nonmonotonic relationship between pulse displacement and the number of evoked spikes. Neurons of interpolaris tended to be more severely nonmonotonic than those of oralis, and some "turned off" at stimulus magnitudes well above threshold. Nevertheless, the number of spikes evoked in either entire sample was a monotonically increasing function of pulse displacement. The range of angular velocity thresholds observed in both second-order samples exceeded three orders of magnitude. As with the angular displacement thresholds, the distributions of angular velocity thresholds were quantitatively different, although their shapes and extremes were similar, and they overlapped extensively. The observed differences of stimulus-response relationships of the neurons in interpolaris and oralis reflect differences in the ways different trigeminal nuclei receive, process, and distribute information to the circuits in which they participate.

Animals↗
PubMed1986

Blindness and partial sight in an elderly population.

A cross sectional, prevalence survey of eye disease in the population over 75 years old of Melton Mowbray has been used to examine the accuracy and completeness of the Blind and Partially Sighted Registers. The Blind Register had high sensitivity and specificity but was found to underestimate the prevalence of blindness by a factor of 1.1. The Partially Sighted Register had high specificity, but the sensitivity was only 50% and it underestimated the prevalence of partial sight by a factor of 1.5. Seven persons eligible for registration, but previously not registered, were found, two as blind and five as partially sighted. This represented 21% of the registrable visually impaired population.

Aged↗
PubMed1986

Senile cataract and senile macular degeneration: an investigation into possible risk factors.

Data from the Melton Mowbray Eye Study and Community Health Study have been used to look for possible risk factors for senile cataract and senile macular degeneration. Significant associations with senile cataract were age, female sex, myopia, social class and antihypertensive treatment, whilst for senile macular degeneration age and the absence of arcus senilis were significant. These observations are presented and discussed in relation to findings from other studies.

Age Factors↗
PubMed1985

Quality control of automated cellular analyses -- the fallibility of embalmed blood.

The use of preserved blood for quality control is well established. The treatment of such materials to extend their life can impart a property to those materials such that external contaminants to diluents used for subsequent analysis may not be detected by these materials and give a false sense of security in a quality control program. The effect of the contaminant on fresh cells is more of a problem. Most contaminants affect cell volume, particularly the red cells which have been studied in-depth. White cell differential screening by size analysis is similarly affected. The recognition of the different properties of fresh and preserved blood helps explain results.

Blood Cell Count↗
PubMed1985

A study of the prevalence of eye disease in the elderly in an English community.

A randomly selected age-stratified sample of subjects 76 years of age and older living in the Melton Mowbray area was examined by an ophthalmologist and an ophthalmic optician. Over a two-year period 484 subjects were examined, with a response rate of 71.5 per cent. The prevalence rates for the major sight threatening conditions in the elderly were determined: senile cataract 46.1 per cent, senile macular degeneration 41.5 per cent and open angle glaucoma 6.6 per cent. These figures are compared to the results of other epidemiological surveys of the elderly.

Age Factors↗
PubMed1984

Does testing of brainstem auditory response aid diagnosis in progressive spastic paraparesis?

40 patients with progressive spastic paraparesis of uncertain cause were studied in order to assess the outcome of their investigations. Abnormalities of the visual evoked response (VER) were found in 33%, indicating a second lesion in the nervous system. An additional 15% had abnormalities of the brainstem auditory evoked potentials (BAEP), indicating an supra-spinal, though not necessarily a second lesion. Qualitative CSF examinations for oligoclonal IgG banding showed abnormality in 30%, and considerable overlap (83%) with the patients who had abnormal VER, but not in those with an abnormal BAEP alone. It is concluded that the BAEP is of value when the VER and CSF are normal.

Brain Stem↗
PubMed1984

Acute anterior uveitis, ankylosing spondylitis, back pain, and HLA-B27.

One hundred and sixty-nine patients with acute anterior uveitis were studied for the presence of HLA-B27 tissue type, radiological evidence of ankylosing spondylitis, and a history of back pain. 60% were male; 45% were HLA-B27+. The male:female ratio in the HLA-B27+ group was the same as in the whole group. 24% had radiological evidence of ankylosing spondylitis, and, of these, 83% were HLA-B27+ while 17% were HLA-B27-. There was a definite correlation between the severity of the ankylosing spondylitis and preponderance of males in the HLA-B27+ group of patients. Significant back pain occurred in 60% of HLA-B27+ patients but in only 14% of HLA-B27- patients. The importance of the selection of patients and of consistency in the use of diagnostic criteria in studies relating to ankylosing spondylitis and acute anterior uveitis is stressed.

Acute Disease↗
PubMed1984

Klebsiella and acute anterior uveitis.

Samples of the faeces of 153 consecutive patients presenting with acute anterior uveitis (AAU), and of 47 controls were examined for the presence of Klebsiella pneumoniae. No increase in the carriage rate of klebsiella was found in the AAU patients as compared with the controls. Furthermore no increase was found in any group of patients whether subdivided by HLA-B27 status, sex, or presence of ankylosing spondylitis (AS). No difference was found between patients having their first attack of AAU and those with recurrences.

Feces↗
PubMed1984

Severe ocular side effects of perhexilene maleate: case report.

We report a case of perhexilene maleate (PEXID) toxicity in which the presenting feature was loss of vision secondary to chronic papilloedema. Vortex keratopathy similar to that seen in amiodarone keratopathy was present, and corneal and conjunctival biopsy findings are presented. To our knowledge this is the first case report of a keratopathy occurring in perhexilene toxicity. After withdrawal of the drug the papilloedema and keratopathy subsided, but some visual deficit remains. The properties of perhexilene maleate and other amphiphilic drugs are described, and the possible aetiology of vortex keratopathy is discussed.

Conjunctiva↗