Biomedical subjects

K Stanton

Publications and source records attributed to K Stanton.

22 records · Page 2Linked to original sources

PubMed1978

The relation between insulin and adipocyte insulin receptors during treatment of human obesity.

Seventeen obese patients were submitted to 1 week's severe then 3 months moderate dietary restriction. The glycaemic and insulinaemic response to oral glucose was measured at baseline, after 1 week and at 3 months, and the results related to adipocyte insulin receptors estimated from fat biopsies taken on each occasion and to the weight lost. Adipocyte insulin binding was found to be significantly inversely correlated with the insulinaemic response to oral glucose (r = -0.54, P less than 0.05), an inverse relationship maintained even after weight loss had been achieved and displayed within as well as between subjects. Variation of 125I-insulin binding to adipocytes was related to receptor number and not to receptor affinity and could not be accounted for by differences in 125I-insulin degradation. Adipose cell size did not correlate significantly either with the insulinaemic response or with cell surface receptor density. The findings suggest: (1) that a significant proportion of obese subjects are not hyperinsulinaemic and that their metabolic response to weight reduction may differ from that of those who are hyperinsulinaemic; (2) that reduced insulin binding to adipocytes in the obese reflects hyperinsulinaemia, when present, and not adiposity as such; (3) that the degree of insulinaemia is a major determinant of the cell surface receptor density.

Adipose Tissue↗

PubMed1976

Quantitative electrocardiography during extended space flight: the second manned Skylab mission.

To assess the effects of space flight on cardiac electrical properties, vectorcardiograms (VCG) were obtained on the Skylab crew at regular intervals during the 59-d flight (SL3) and during the pre- and postflight periods. The Frank lead system was used and observations were made at rest; during 25%, 50%, and 75% of maximum exercise; during a short pulse of exercise (150 W, 2 min); and after exercise. Data from 47 in-flight tests were analyzed by computer and compared to preflight and postflight values. A statistically significant increase in QRS maximum vector magnitude (all SL3 crewman); and an increase in resting PR interval (all SL3 crewmen) occurred. During exercise, the PR interval did not differ from preflight. Exercise heart rates in flight were same as preflight, but increased in the immediate postflight period. No major changes in QRS, T, or ST vector direction occurred. The scientist pilot had premature ventricular beats sporadically during the flight. This astronaut also had intermittent periods of atrioventricular junctional rhythm throughout the flight. The increase in QRS maximum vector magnitude resembles the electrocardiographic changes associated with athletic conditioning and may be related to increased ventricular volume secondary to centripetal shifts of fluid and/or the in-flight isotonic exercise program. Prolongation of the PR interval at rest with normalization of exercise suggests that there was increased vagal tone or suppressed sympathetic influence during the flight.

Adult↗

PubMedDate not supplied

Quantitative electrocardiography during extended space flight.

To assess the effects of prolonged space flight on the electrophysiological properties of the heart, vectorcardiograms (VCG) were obtained on the Skylab crews at regular intervals during flight and the pre- and postflight periods. The VCG signals were telemetered from Skylab and analyzed by digital computer. Conventional 12-lead electrocardiograms were derived from the VCG signals by a lead transformation program. Standardized exercise loads were incorporated into the experiment protocol to increase the sensitivity of the VCG for effects of deconditioning and to detect susceptibility for arrhythmias. In Skylab II, 24 preflight, 21 inflight, and 19 postflight experiments were analyzed. Statistically significant inflight changes observed in two or more crew members included: decreased resting heart rate, increased QRS duration, anterior shift QRS vector, increased QRS vector magnitude, anterior shift T vector, and increased T vector magnitude. One astronaut had occasional premature ventricular contractions (PVC) during the pre- and postflight phases. He had a single episode of multiple PVC's during heavy-load exercise testing in flight. A second astronaut had no arrhythmia during pre- or inflight testing. On postflight day 21 he had multiple PVC's and salvos of ectopic ventricular beats. He has had no recurrence of the arrhythmia. With the exception of the cardiac arrhythmias, no deleterious electrophysiological changes were observed during Skylab II.

Arrhythmias, Cardiac↗

PubMedDate not supplied

Elder acceptance of health monitoring devices in the home.

This study examined frail elders' acceptance of the concept of home monitoring devices. With the potential of such devices to ultimately assist many older persons, acceptance of the device in the individual's home is a critical component. Elders who view devices negatively--as unnecessary, unattractive, or intrusive--may be less likely to use the device if installed or less likely to allow them to be installed. For the participants in the current study, the results suggest strong acceptance of the concept of home health monitoring and the devices to make the system work. When questioned on device appearance a majority of the subjects felt that the devices would be acceptable in their homes, and initial reactions to the devices were primarily favorable. Equipment characteristics have been identified as one of the determining factors of perceived intrusiveness of home monitoring devices (Fisk, 1997). Study participants made several suggestions pertaining to device features and appearance. A common criticism related to device size, especially concerning the blood pressure cuff which was referred to as "gaudy" by one study participant. Participants offered suggestions such as making devices smaller, providing control for volume adjustment, and providing voice activation. At least one participant expressed a concern over device functioning in the event of distance traveling. Subjective comments such as "I think it would help many people," "It's very reasonable and important in several ways," and "...people would be more independent and safe," provided anecdotal support of device acceptance. Although a majority of the study participants had favorable responses to the devices and monitoring systems, many of their subjective comments reflected positive views regarding use by others as opposed to personal use. This finding may suggest that the participants did not personally identify with the need to use such devices but rather viewed the devices as relevant and acceptable for "the person who absolutely needs it." However, a majority of the participants identified "relieving personal worry" as a possible benefit of the home monitoring system which suggests personal identification with the potential benefits. The findings of study participants' willingness to pay, and a desire to maintain communications on a consistent basis with monitoring services, may demonstrate overall acceptance of the idea of home monitoring devices/services and establishes a need for continued research in product development. During the interviews, many of the subjects expressed enthusiasm and interest over the prospect of the home monitoring devices and systems with which they were relatively unfamiliar. This suggests a need for further consumer education regarding use of home monitoring devices and systems. Aside from the relatively small sample size, one limitation of this study relates to the study participants' understanding of the devices in relation to their current needs. The questionnaire results provided hypothetical acceptance of devices from a usefulness and aesthetic point of view. However, the findings may not totally reflect the study participants' actual willingness or desire to utilize the applicable devices in their homes. Further research is suggested in the area of assessment of potential consumer groups' perceptions of their current health status, functional limitations and needs, and more extensive research regarding perceptions of the potential benefits of using home monitoring devices. Further research in product development and clinical trials of existing home monitoring devices is also recommended.

Activities of Daily Living↗