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Biomedical subjects

D MacEwan

Publications and source records attributed to D MacEwan.

6 recordsLinked to original sources
PubMed1996

Influence of magnetic resonance imaging on diagnosis and therapeutic intention.

RATIONALE AND OBJECTIVES: We assessed the contribution of magnetic resonance (MR) imaging to diagnostic and therapeutic decision making. METHODS: In a before-after observational study, we collected information from clinicians before and after patients were given MR examinations. We studied 406 cases selected from consecutive referrals to a single MR imaging facility in Manitoba between November 1, 1991, and October 30, 1992, for diagnosis of suspected brain, spinal column, or large-joint disorder. We examined changes in diagnoses, changes in clinician diagnostic confidence, and changes in therapeutic intentions after MR examinations. RESULTS: Overall, MR imaging findings contributed to a change in referring physicians' diagnoses or diagnostic confidence in 76% of the cases. Referring physicians reported a change in provisional diagnosis in 42% of the cases. In 67% of these cases, the referring physician's provisional diagnosis was ruled out by normal examination findings; in the remaining 33% of the cases, an alternate diagnosis was offered by the consulting radiologist. In the 58% of the cases in which the provisional diagnosis was not altered by MR imaging findings, clinical confidence in the provisional diagnosis increased in 46% of the cases and decreased in 12% of the cases. Management plans were reported to be altered in 54% of the cases; in 24% of the cases, therapeutic intentions changed from lower to higher levels of intervention. CONCLUSION: Although MR imaging had a substantial influence on clinicians' decisions concerning diagnoses, the influence of MR imaging findings on therapeutic decision making, and therefore on patients' health status, was more moderate.

Brain Diseases↗
PubMed1993

Functional expression of 5-HT1c receptor cDNA in COS 7 cells and its influence on protein kinase C.

Two subtypes of receptors for serotonin (5-hydroxytryptamine; 5-HT) are known to stimulate inositol (1,4,5)-trisphosphate production, the 5-HT1c and 5-HT2 receptors. In this study we investigated the ability of 5-HT1c receptors, transiently expressed in COS 7 cells, to functionally interact with protein kinase C-alpha, the indigenous (phorbol ester-responsive) isoform of the enzyme in those cells. Serotonin caused translocation of the [3H]phorbol 12,13-dibutyrate (PDBu) binding site of PKC-alpha from the cytosolic to the membrane fraction in a Ca(2+)-dependent manner which was prevented by the 5-HT1c receptor antagonist mianserin. The lipid activators of PKC, PDBu and 1,2-dioctanoyl-sn-glycerol (DOG) also caused translocation, but through a mechanism apparently quite independent of Ca2+.

Animals↗