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Biomedical subjects

G H Dodd

Publications and source records attributed to G H Dodd.

32 records · Page 2Linked to original sources
PubMed1976

Fluorimetric determination of the resting potential changes associated with the chemotactic response in Paramecium.

(1) Evidence is presented which indicates that the carbocyanine dye (3,3'-dipropyl thiadicarbocyanine) can be used as a spectroscopic probe for monitoring the resting potential across tha plasma membrane of the ciliated protozoan Paramecium. (2) The dye at low concentrations (less than or equal to 1 muM) does not affect either the viability or the motility of the cells, nor does it induce a chemotactic response. (3) The fluorescence of the dye bound to the cells alters as the potential across the membrane is changed by increasing the external cation concentration. (4) The absorbance of the bound dye also changes in response to an alteration of the membrane potential. (5) The membrane potential changes as measured by the fluorescence method have been correlated with the measurements of the potential estimated by microelectrode methods. (6) Both cations which induce a negative chemotactic response in Paramecium (K+, Na+, Ba2+) and several non-toxic cations bring about a rapid depolarization of the plasma membrane. The significance of these rapid changes in relation to the swimming behaviour of the ciliate is discussed.

Animals↗
PubMedDate not supplied

Unconscious odour conditioning in human subjects.

In the first session, two groups of male and female subjects were given a stressful task involving the completion of eleven WAIS block patterns under time limitations. A low intensity of a neutral odour (TUA) was present for half of the subjects. During a second session several days later, subjects completed a mood rating scale and then entered a room, where the odour of TUA was present, to judge a series of photographs of people and complete a second mood rating scale. During the first session female subjects completed significantly fewer block patterns, and completed fewer correct designs. In the second session, female subjects who had experienced TUA odour in the stress condition showed an increase in anxiety ratings. They also had higher ratings scores when judging the photographs. In contrast, subjects who did not experience odour during the stress session became calmer during the second session. None of the female subjects reported perceiving the odour irn either session. As both pairing and elicitation occurred at low levels of awareness, the study demonstrates how odours might acquire values through pairing with emotionally significant events.

Affective Symptoms↗
PubMedDate not supplied

Skin conductance and subjective assessments associated with the odour of 5-alpha-androstan-3-one.

Two experiments are reported using the odours of 5-alpha-androstan-3-one (androstanone) and, a control odour, aurantiol. Various measures of skin conductance (SC) were recorded and analysed and subjects also rated the odours using analogue scales. The first experiment involved comparisons between subjects who perceive the androstanone odour as pleasant and subjects who perceive it as unpleasant. A number of differences were shown between the two groups and also between androstanone and aurantiol. The results are interpreted as demonstrating the influence of cognitive factors that are found between male and female responses and also between the responses of the 'pleasant' and 'unpleasant' groups. The second experiment examined the SC response of subjects who displayed specific anosmia to the odour of androstanone. The results suggest that the concept of specific anosmia requires modification.

Animals↗