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Biomedical subjects

M Gwynn

Publications and source records attributed to M Gwynn.

6 recordsLinked to original sources
PubMed1999

The effect of decreasing digital image resolution on teledermatology diagnosis.

OBJECTIVE: To determine the effect of degraded digital image resolution (as viewed on a monitor) on the accuracy and confidence of dermatologic interpretation. MATERIALS AND METHODS: Eight dermatologists interpreted 180 clinical cases divided into three Logical Competitor Sets (LCS) (pigmented lesions, non-pigmented lesions, and inflammatory dermatoses). Each case was digitized at three different resolutions. The images were randomized and divided into (9) 60-image sessions. The physicians were completely blinded concerning the image resolution. After 60 seconds per image, the viewer recorded a diagnosis and level of confidence. The resultant ROC curves compared the effect of LCS, level of clinical difficulty, and resolution of the digital image. One-way analysis of variance (ANOVA) compared the curves. RESULTS: The areas beneath the ROC curves did not demonstrate any consistently significant difference between the digital image resolutions for all LCS and levels of difficulty. The only significant effect observed was amongst pigmented lesions (LCS-A) where the ROC curve area was significantly smaller in the easy images at high resolution compared to low and medium resolutions. For all other ROC curve comparisons within LCS-A, at all other levels of difficulty, as well as within the other LCS at all levels of difficulty, none of the differences was significant. CONCLUSION: A 720 x 500 pixel image can be considered equivalent to a 1490 x 1000 pixel image for most store-and-forward teledermatology consultations.

Analysis of Variance↗
PubMed1995

Expectations and sequelae to hypnosis: initial findings.

As part of the introduction to an experiment using the Harvard Group Scale, subjects were given one of three brief instructions before being hypnotized: (1) no mention of negative or positive aftereffects, (2) vague warning of negative aftereffects, i.e., "some mildly unpleasant experiences", plus, "most persons report their experiences to be pleasurable and interesting", (3) specific warning of negative aftereffects, i.e., "approximately one half subjects have reported mild, short-term aftereffects such as headache", etc. (no positive information). The "specifically warned" Ss showed more negative aftereffects than both of the other groups, and the "no mention" Ss showed more than the "vaguely warned" Ss. The positive suggestions in the "vaguely warned" Ss instructions may have confounded the expectation for negative effects. A follow up study used instructions varying only in the degree of expectations for negative aftereffects (no mention of positive aftereffects). The results did not show group differences in negative aftereffects as predicted, however, correlational results suggested some interesting interactions among subject variables and the type of prehypnotic instructions administered.

Humans↗
PubMed1993

tPA in acute stroke--risk or reprieve?

Stroke outcome is measured by survival and disability. Since more patients are surviving stroke, researchers are pursuing ways to reduce the severity of neurological deficits. Anticoagulant treatment with heparin prevents, rather than treats, thrombotic or embolic occlusions; therefore, the search for safer thrombolytic preparations continues. Tissue plasminogen activator is currently under investigation as an effective, safe treatment for acute stroke patients. However, the administration of tPA carriers a risk of hemorrhage. Although this article discussed tPA administered with an arteriogram based protocol, tPA investigation occurs using other protocols. Once acute stroke patients receive tPA, then measures to prevent complications and manage the stroke symptoms determine the risks and benefits patients receive. Nursing management of these patients can contribute to these benefits.

Acute Disease↗
PubMed1984

Suffering for science: the effects of implicit social demands on response to experimentally induced pain.

In two experiments subjects rated their pain during baseline trials of cold pressor and finger pressure pain. After various instructional treatments, they were posttested with these same stimuli. As in previous studies, we found in both experiments that coping suggestions significantly reduced reported pain. Experiment 1, however, demonstrated that subjects often refrained from using available cognitive coping strategies to reduce pain unless they had been given explicit permission to do so. Experiment 2 replicated this finding and also showed that explicit permission to "do whatever you can to reduce pain" was as effective as a coping suggestion in decreasing reported pain. These findings indicate that subjects' interpretation of what is appropriate responding in the test situation determines how they choose to cope with the painful stimulation. Thus standard experimental procedures for assessing baseline levels of pain implicitly lead subjects to refrain from coping and thereby tend to underestimate their ability to control pain. Moreover, suggestions and other instructional techniques for coping with pain may produce much of their effect not by teaching subjects new coping skills but instead by giving them permission to use already available coping strategies.

Adolescent↗
PubMed1983

MM 14201, a new epoxyquinone derivative with antibacterial activity produced by a species of Streptomyces.

A new antibiotic designated MM 14201 has been detected in a culture of Streptomyces sp. NCIB 11813. Methods for the production and purification of MM 14201 are described. Biological evaluation has shown it has broad spectrum antibacterial activity being most effective against Serratia and Pseudomonas sp. Structural studies are reported which have demonstrated MM 14201 is a new epoxyquinone derivative.

Anti-Bacterial Agents↗