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Biomedical subjects

E M Wilson

Publications and source records attributed to E M Wilson.

192 records · Page 11Linked to original sources
PubMedDate not supplied

The androgen receptor gene is located on a highly conserved region of the X chromosomes of marsupial and monotreme as well as eutherian mammals.

The androgen receptor gene (AR), which is located on the long arm of the human X chromosome, was mapped by somatic cell analysis and in situ hybridization in marsupial and monotreme species. Both methods demonstrated that it was located on the X chromosome in each marsupial species, and also in the platypus. We conclude that this gene is part of a highly conserved region of the mammalian X, represented by the human Xq, which formed part of the X chromosome in a mammalian ancestor 150 million years ago. Since this gene is located proximally on the long arm of the monotreme X, which is G-band homologous to the Y and apparently exempt from X chromosome inactivation, the conservation of this region has evidently not depended on its isolation by X-Y differentiation or on X inactivation.

Animals↗
PubMedDate not supplied

Measurement of activated rCBF by the 133Xe inhalation technique: a comparison of total versus partial curve analysis.

An initial assessment of the differential sensitivity of total versus partial curve analysis in estimating task related focal changes in cortical blood flow measured by the 133Xe inhalation technique was accomplished by comparing the patterns during the performance of two sensorimotor tasks by normal subjects. The validity of these patterns was evaluated by comparing them to the activation patterns expected from activation studies with the intra-arterial technique and the patterns expected from neuropsychological research literature. Subjects were 10 young adult nonsmoking healthy male volunteers. They were administered two tasks having identical sensory and cognitive components but different response requirements (oral versus manual). The regional activation patterns produced by the tasks varied with the method of curve analysis. The activation produced by the two tasks was very similar to that predicted from the research literature only for total curve analysis. To the extent that the predictions are correct, these data suggest that the 133Xe inhalation technique is more sensitive to regional flow changes when flow parameters are estimated from the total head curve. The utility of the total head curve analysis will be strengthened if similar sensitivity is demonstrated in future studies assessing normal subjects and patients with neurological and psychiatric disorders.

Administration, Intranasal↗
PubMedDate not supplied

Comparison of external lung monitoring with end-tidal air detection using the 133xenon inhalation method.

When the 133Xe inhalation method is employed for measuring regional cerebral blood flow, the arterial 133Xe concentration is usually approximated by the end-tidal air concentration. However, this approximation may be invalid in the presence of certain lung pathologies or when the breathing pattern is irregular. Jaggi and Obrist, using an intravenous injection of 133Xe, suggested that the counts detected by an external lung probe could provide an alternative estimate for arterial blood concentration once the noise produced by 133Xe in superficial tissues is removed from the signal. A mathematical model, based on hypotheses similar to theirs is presented here together with a new computational procedure for removing the noise. Results from normal rest studies on ten healthy young males indicate that the approximations for arterial blood concentration obtained from end-tidal air and from corrected lung counts are not equivalent when 133Xe is administered by inhalation. The concentration-time curves have different shapes, and these differences are reflected in blood flow values computed by head channel. However, there is no effect on comparisons between homologous regions of the left and right hemispheres.

Administration, Intranasal↗
PubMedDate not supplied

Regional cerebral blood flow by 133xenon inhalation.

Repeated measurements of regional cerebral blood flow (rCBF) were made by the short (ten minutes) 133Xenon inhalation technique and bicompartmental analysis in 11 patients with cerebrovascular disorders, mainly acute cerebral infarction. rCBF was measured 3 to 11 times during one to two weeks. The blood flow of the fast compartment (f1) was calculated as well as the relative weight of this compartment (w1, assumed to correspond to gray matter). In addition a new flow index, the Initial Slope Index (ISI) modified for the inhalation technique, was used. This index of predominantly gray matter flow was calculated from a one-minute epoch of the early part of the clearance curve corrected for recirculation. In three of the patients the f1 and ISI varied in parallel and the w1 showed generally only minor variations from one measurement to the other. However, in the other eight patients fluctuation of the w1 and f1 values were seen which often showed no meaningful relation to the clinical course. The observed w1 changes indicated that some tissues (slowly perfused gray matter and/or rapidly perfused white extracerebral tissues) fluctuate between the fast and the slow compartment. In such cases the f1 values obtained cannot be used for comparison between measurements, since they represent flow rates of varying tissues and do not always represent a true gray matter blood flow. In these patients the ISI, which is independent of such weight changes, showed moderate and clinically likely variations.

Adult↗
PubMedDate not supplied

133Xenon inhalation method. Analysis of reproducibility: some of its physiological implications.

Regional cerebral blood flow (rCBF) was simultaneously measured at seven locations in each hemisphere by the Obrist 133Xenon inhalation method. In each of 35 healthy right-handed subjects two rest measurements were performed on consecutive days. The data analysis comprises the two-compartmentally derived parameters for flow (f1), relative tissue weight (w1), and fractional flow (FF1) respectively of the first compartment, and in addition the initial slope index (ISI). At each detector location the coefficient of variation (C.V.) of the change from first to second measurement was on average 10.4% (ISI), 14.2% (f1), 7.2% (w1), and 2.9% (FF1) respectively. However, when each regional measurement was expressed as a percentage of its hemispheric mean, the C.V. of the intermeasurement change was on average 4.4% (ISI), 7.0% (f1), 7.7% (w1), and 1.9% (FF1) respectively; that of the hemispheric means of ISI, f1, and FF1 was found to be distinctly larger, whereas that of w1 was about equal in size. The interhemispheric coefficient of variation for the change of the hemispheric means from first to second measurement was only 2.3% (ISI), 4.4% (f1), 1.6% (w1), and 1.1% (FF1) respectively. The findings suggest that (1) the variability of rCBF from subject to subject and in consecutive measurements in the same subject is to a substantial degree of physiological origin, and that (2) there are two determinants of rCBF which may operate independently: a determinant of the hemispheric mean level, probably a single determinant for both hemispheres, and a set of determinants for each separate regions superimposed on the hemispheric mean level.

Adolescent↗
PubMedDate not supplied

133Xenon inhalation method: significance of indicator maldistribution for distinguishing brain areas with impaired perfusion. An index for total flow.

This paper introduces a new index for the assessment of regional cerebral blood flow. The index is proportional to total flow, and is obtained from the ratio of regional count rate to arterial indicator input to a region. This index is a more sensitive indicator of impaired perfusion than the traditional flow rate indices which express flow per unit mass of tissue per minute. It accounts for brain tissue partly or totally deprived of its blood supply. Examples of clinical application are reported. A good correlation with the findings of computer-assisted tomography has been found.

Adult↗
PubMedDate not supplied

Consumer decision processes in emergency medical situations.

This paper examines the nature of the consumer decision process in the selection of emergency medical services. Through telephone interviews, 604 respondents were asked to indicate how they would respond to potentially serious medical symptoms. Consumers tend to perceive such medical situations as having high personal involvement requiring extended decision making. This decision making approach results in a delayed response to serious symptoms. Factors that influence the outcome of consumer decision making include a favorable perception of EMS and knowledge about aspects of the EMS system. The conclusion is that marketing programs that aim to improve levels of appropriate use of EMS should educate consumers about the prehospital EMS system and strategically intervene in this decision process.

Connecticut↗