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Biomedical subjects

C Melvin

Publications and source records attributed to C Melvin.

5 recordsLinked to original sources
PubMed2004

Managing errors in radiology: a working model.

AIM: To develop a practical mechanism for reviewing reporting discrepancies as addressed in the Royal College of Radiologists publication "To err is human. The case for review of reporting discrepancies". MATERIALS AND METHODS: A regular meeting was developed, and has evolved, within the department to review discrepancies. Standard forms were devised for submission of cases as well as recording and classification of discrepancies. This has resulted in availability of figures that can be audited annually. RESULTS: Eighty-one cases involving error were reviewed over a 12-month period. Seven further cases flagged as discrepancies were not identified on peer review. Twenty-four reports were amended subsequent to the meeting. Nineteen additional cases were brought to the meeting as illustrative of teaching points or for discussion. CONCLUSION: We have evolved a successful process of reviewing reporting errors, which enjoys the confidence and support of all clinical radiologists, and is perceived as a method of improving patient care through an increasing awareness of lapses in performance.

Clinical Competence↗
PubMed1987

Dose-dependent effects of a pyridoquinazoline thromboxane synthetase inhibitor on arachidonic acid metabolites and hemodynamics during E. coli endotoxemia in anesthetized sheep.

We investigated the effects of a new pyridoquinazoline thromboxane synthetase inhibitor infused before administering Escherichia Coli endotoxin into 18 anesthetized sheep with lung lymph fistulas. In normal sheep increasing plasma Ro 23-3423 concentrations were associated with increased plasma levels of 6-keto-PGF1 alpha, a reduced systemic vascular resistance (SVR, r = -0.80) and systemic arterial pressure (SAP, r = -0.92), the mean SAP falling from 80 to 50 mm Hg at the 20 and 30 mg/kg doses. Endotoxin infused into normal sheep caused transient pulmonary vasoconstriction associated with increased TxB2 and 6-keto-PGF1 alpha levels while vasoconstriction and TxB2 increase were significantly inhibited by pretreatment with Ro 23-3423 in a dose-dependent manner. When compared to controls, plasma and lymph levels of 6-keto-PGF1 alpha, PGF2 alpha and PGE2 after endotoxin infusion were increased several-fold by administering Ro 23-3423 up to plasma levels of 10 micrograms/ml. Doses over 30 mg/kg with blood levels above 10 micrograms/ml reduced plasma and lymph levels of 6-keto-PGF1 alpha, PGF2 alpha and PGE2, suggesting cyclooxygenase blockade at this dose. The peak 6-keto-PGF1 alpha levels at 60 min after endotoxin infusion in sheep with Ro-23-3423 levels below 10 micrograms/ml were associated with the greatest systemic hypotension due to a reduced SVR (r = -0.86). After endotoxin infusion the leukotrienes B4, C4, D4 and E4 in lung lymph were assayed by radioimmunoassay and high pressure liquid chromatography and remained at baseline values.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Cyclooxygenase blockade elevates leukotriene E4 production during acute anaphylaxis in sheep.

We examined changes in the levels of eicosanoids in blood and pulmonary lymph of anesthetized sheep undergoing acute anaphylaxis. Within 1-3 min of intravenous antigenic challenge of previously sensitized sheep, there were approximately 7-30-fold elevations in mean arterial plasma levels of thromboxane B2 and 6-ketoprostaglandin F1 alpha, respectively, as measured by RIA. Negligible changes in levels of these cyclooxygenase products were found in both nonsensitized sheep and in sensitized sheep treated with indomethacin before antigenic challenge. In contrast, no changes in levels of sulfidopeptide leukotrienes (SPLT) in pulmonary lymph were detectable by RIA during anaphylaxis in sensitized or nonsensitized sheep, but levels of SPLT in indomethacin-treated sensitized sheep increased more than fivefold above levels in lymph from both other groups of animals. The immunoreactive SPLT in lymph from indomethacin-treated sheep was accounted for as LTE4, as demonstrated by mobility on HPLC and absorbance at 280 nm. These results support the possibility that certain undesirable effects of nonsteroidal antiinflammatory drugs, such as cardiopulmonary reactions in aspirin-sensitive individuals, and impaired renal and cardiac function during therapy with these drugs, may be related in part to augmented synthesis of the 5-lipoxygenase pathway products, especially those of the sulfidopeptide class. Increased LT production could also limit the antiinflammatory effectiveness of these drugs in many disease states.

6-Ketoprostaglandin F1 alpha↗