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Biomedical subjects

P R Marshall

Publications and source records attributed to P R Marshall.

6 recordsLinked to original sources

The ARTS study (Arterial Revascularization Therapies Study).

The rising costs of health care have forced policy makers to make choices, and new treatments are increasingly assessed in terms of the balance between additional costs and additional effects. The recent recognition that stenting has a major and long-lasting effect enhancing balloon PTCA procedure has made it imperative to compare in patients with multivessel disease the standard surgical procedure with multiple stenting in a large scale multinational and multicentre approach (19 countries, 68 sites). Selection and inclusion of patients is based on a consensus of the cardiac surgeon and interventional cardiologist on equal 'treatability' of patients by both techniques with analysis of clinical follow-up (event-free survival) on the short (30 day), medium (1 year), and long-term (3 and 5 year) with analysis of cost-effectiveness and quality of life (EuroQol and SF-36). Of the entire trial, the primary null hypothesis which needs to be rejected is that there will be no difference in event-free survival or effectiveness (E), at 1 year and also that the direct and indirect costs (C) per event-free year are not different between surgery or stenting. For this to become significant with a power of 90% one needs 1200 patients. Between April 97 and June 98, 1205 patients have been randomized with a monthly recruitment of 83 patients. Expected costs, effects and cost-effectiveness ratio (CE ratio) are: Stent high costs 2 VDStent high costs 3 VDStent low costs 2 VDStent low costs 3 VDCABG costs (C)$19.297$24.566$16.638$20.456$21.350 effects (E)81%81%81%81%88% CE ratio$23.876$30.397$20.586$25.322$24.348 Clinically, stenting is not expected to be more effective than CABG, but should be cost effective in both the 2- and 3-VD group when using the lower cost estimate and in the 2 VD group when using the higher cost assumptions.

Angioplasty, Balloon, Coronary↗

Altered cations and muscle membrane ATPase activity in deoxycorticosterone acetate-salt spontaneously hypertensive rats.

The role of ions and cell membrane function in the pathogenesis of benign and malignant hypertension was investigated in spontaneously hypertensive rats (SHR). Ten-week-old male SHR (n = 50) and SHR treated with deoxycorticosterone acetate (DOCA; n = 70) and 1% NaCl drinking water were studied weekly for 14 weeks. Malignant hypertension developed only in DOCA-salt SHR and was characterised by severe hypertension, failure to thrive and renal fibrinoid necrosis. Fourteen DOCA-salt SHR and one SHR died. Extracellular (serum) and intracellular (erythrocyte and muscle) Na+, K+, Mg2+, Ca2+ and muscle membrane Na+,K(+)-adenosine triphosphatase (ATPase), Ca(2+)-ATPase and Mg(2+)-ATPase were measured at various stages in the development of malignant hypertension. Three developmental phases were defined: benign, premalignant and malignant. DOCA-salt SHR showed persistent hypokalaemia. In the benign phase, there were no differences in Na+, Mg2+ and Ca2+ between SHR and DOCA-salt SHR. In the premalignant phase, serum and erythrocyte Mg2+ and ATPase activity were significantly lower in DOCA-salt SHR compared with SHR. During the late premalignant and malignant phases, intracellular Ca2+ and Na+ were significantly higher in the DOCA-salt SHR compared with SHR. In view of these findings, the abnormalities in DOCA-salt SHR during the early phases of blood pressure elevation could be contributory factors to the development of malignant hypertension.

Adenosine Triphosphatases↗