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Biomedical subjects

M Cook

Publications and source records attributed to M Cook.

At least 163 records · Page 9Linked to original sources
PubMed1982

Radiographic morphometry and radiographic photodensitometry of the femur in the Beagle at 13 and 21 months.

A study was made of x-ray morphometry and x-ray photodensitometry of bones of 2 small groups of healthy standardized colony-raised male research Beagles, ages 13 and 21 months. The morphometry and photodensitometry results were correlated to other variables of interest. The total width of the femur and its optical density to x-rays increased significantly with age and body weight, but not so the length of the femur nor the combined cortical thickness (CCT). This last measurement (CCT) did not increase in parallel with the whole length of the bone either. The CCT/width ratio decreased as body weight increased. The clear-cut increase in the optical density of the whole bone is therefore explained by the age-related variations in bone envelope activity.

Absorptiometry, Photon↗
PubMed1981

Anhedonia and schizophrenia.

Data from Chapman's anhedonia and perceptual aberration scales are presented for groups of schizophrenics and hospital staff control subjects. Differences between the two groups are found for both anhedonia scales and for the perceptual aberration scale, but the difference for physical anhedonia is only marginally significant. The anhedonia scales do not differentiate between the two groups sufficiently well to be useful diagnostically.

Adult↗
PubMed1979

Attentional deficit in the siblings of schizophrenics.

A study of attentional deficit in the relatives of schizophrenics and in a matched control group is reported, in which the relatives are found to have poorer scores on a vigilance test and on a choice reaction time test. It is concluded that this deficit points to one of the primary symptoms of schizoprenia, and suggestions for further research are made.

Adolescent↗
PubMed1979

Gaze patterns of mentally retarded adults in two contrasting environments.

Two matched samples of mentally retarded adults were video recorded on two occasions, before and after one group was transferred to a different type of hospital, and their gaze patterns analyzed. Overall, only slight changes after transfer were found, but analysis according to amount of looking at the interviewer on the first occasion showed that those transferred subjects who initially looked little of the time significantly increased their amount of looking after transfer. Some correlations with the Adaptive Behavior Scale were also reported.

Adult↗
PubMed1978

The perception of solid form in early infancy.

Day and McKenzie determined the rate of habituation of fixation of young infants to repeated visual presentations of a cube. They found the habituation rate to be the same when the stimulus orientation changed between presentations as when it was fixed, and they interpreted this as evidence of shape constancy. However, a failure to discriminate between cubes in different orientations is only evidence of shape constancy if the infant can at the same time discriminate the cube from other cubelike forms. The experiment described here contrasted the rate of habituation of fixation of 12-week-old infants to a homogenous stimulus series (a cube presented in different orientations) with the rates of habituation to various heterogeneous series, in each of which a cube was alternated with some other solid. It was found that, while the infant could distinguish a cube from a photograph of a cube and a concave solid (an L-form), there was no evidence of discrimination between the cube and either a wedge or a truncated pyramid. The results imply limits to the young infants capacity to resolve solid form.

Discrimination Learning↗
PubMed1977

Esterase isozyme patterns in developing embryos of Brachydanio rerio (zebra danio), Brachydanio abolineatus (pearl danio), and their hybrids.

The ontogeny of esterase isozymes in Brachydanio rerio (zebra danio), Brachydanio albolineatus (pearl danio), and hybrids formed by their reciprocal crosses was investigated using polyacrylamide disc electrophoresis. Seven esterase isozymes were identified in each species from the unfertilized egg stage to nine days posthatch. Electrophoretic analysis of qualitative changes in enzyme pattern indicated that some esterases were present at all stages of development while other esterases abruptly appeared at a specific stage of morphological differentiation. The esterases of both species were classified on the basis differential substrate and inhibitor specificities. In developing hybrids formed by B. rerio eggs inseminated with B. albolineatus sperm, the maternal isozyme pattern persisted until Stage 17 (gastrulation). Embryonic extracts from Stage 17 onward showed a slow-moving, DFP-sensitive carboxylesterase of paternal origin. In developing hybrids formed by B. albolineatus eggs inseminated with B. rerio sperm, a paternal contribution to the esterase pattern was probably present by the end of gastrulation; esterase activity of distinctively paternal origin was present by Stage 22 (retinal pigmentation) The maternal contribution to the total esterase profile appeared to remain high through hatching. Additional evidence for gene activity at gastrulation was obtained in experiments utilizing actinomycin-D and cycloheximide. Results of exposing embryos of B. rerio to 15 mug/ml of actinomycin-D indicated that transcription of the template RNA coding for cholinesterase occurred during gastrulation or some 20-30 hours prior to the appearance of the isozyme at Stage 22. This template RNA was translated sometime during that 10-hour interval immediately preceding Stage 22.

Animals↗
PubMed1975

The role of gaze in impression formation.

Three hypotheses about the effects of amount of gaze on the impression created of six confederates were tested, using rating scales and free descriptions. The first hypothesis--that favourableness of impression would be a linear function of amount of gaze--was partly confirmed. The second hypothesis--that favourableness of impression would be a curvilinear function of amount of gaze--was not confirmed, nor was the third hypothesis--that effect of gaze would be a complex function of sex of subject and sex of gazer. The effects of gaze were not as marked as had been predicted. The free descriptions also provided data on the number and type of subjects who commented on the amount of gaze of the confederate. Three possible explanations of the results are discussed.

Eye Movements↗
PubMed1975

Anxiety and ritualized speech.

The experiment examines the effects on a number of words that seem irrevelant to semantic communication. The Units of Ritualized Speech (URSs) considered are: 'I mean', 'in fact', 'really', 'sort of', 'well', and 'you know'. Two hypotheses are tested: (i) that URS rate will increase with anxiety; and (ii) that the speaker's preferred URS will increase with anxiety. Subjects were interviewed on topics they had previously rated as anxiety-provoking and non-anxiety-provoking. Hypothesis (i) was supported, but hypothesis (ii) was not. More specifically, the use of 'I mean' and 'well' increases when the speaker is anxious. Explanation for this is sought in the grammatical location of these two units. Sex differences in the use of URSs, correlations between URSs and their relationship to other forms of disfluency are also considered.

Anxiety↗