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Biomedical subjects

R Johnson

Publications and source records attributed to R Johnson.

778 records · Page 44Linked to original sources
PubMedDate not supplied

Erythropoietin with oral iron in peritoneal and hemodialysis patients. A comparison in an inner city population.

Studies on the comparative efficacy of erythropoietin (rHuEPO) in chronic hemodialysis (HD) and peritoneal dialysis (PD) patients are scarce. The authors compared the use of rHuEPO in 74 stable patients on hemodialysis with 24 on chronic peritoneal dialysis. All patients were on oral iron supplements. In PD patients, hematocrits were 23.1 and 30.1%, rHuEPO dose 80.9 and 89.0 U/kg/wk, whereas in HD patients, hematocrits were 21.2 and 27.5 and rHuEPO dose was 140.2 and 165.0 U/kg/wk at initiation and 6 months, respectively. Serum iron and transferrin saturations were unchanged in peritoneal, but decreased in hemodialysis patients on rHuEPO therapy. These findings suggest that rHuEPO is more effective in peritoneal dialysis patients than in hemodialysis patients receiving oral iron. The improved efficacy of rHuEPO in peritoneal dialysis may be due to decreased blood loss, subcutaneous administration, or better removal of inhibitors of erythropoiesis. Peritoneal dialysis may be more cost effective and desirable than hemodialysis for rHuEPO dependent or resistant patients.

Administration, Oral↗
PubMedDate not supplied

Effects of simvastatin and enalapril on serum lipoprotein concentrations and left ventricular mass in patients on dialysis. The Perfect Study Collaborative Group.

A randomised trial of simvastatin and enalapril in patients with chronic renal failure on dialysis: effects on serum lipoprotein concentrations and left ventricular mass. Left ventricular hypertrophy and abnormalities of lipoprotein metabolism are both possible contributors to the high risk of cardiovascular death in patients with chronic renal failure on dialysis. We investigated the effects of simvastatin on lipid and lipoprotein concentrations and the effects of enalapril on left ventricular mass in 107 patients receiving haemodialysis or continuous ambulatory peritoneal dialysis. Patients were randomised in a factorial design to receive simvastatin (10 mg daily) or placebo and enalapril (2.5-5 mg daily) or placebo. During follow-up, there was a significant excess of patients withdrawn from enalapril because of hypotension (2p = 0.002), and after 6 months only 55% of those assigned enalapril were still on treatment. From baseline to 6 months, there were no statistically significant differences in left ventricular mass or left ventricular dimensions between patients assigned enalapril and those assigned placebo. Among the patients assigned simvastatin, total cholesterol was reduced by 13% (2p = 0.001), LDL cholesterol was reduced by 17% (2p = 0.003) and apolipoprotein B was reduced by 12% (2p = 0.005) compared to patients assigned placebo. There were borderline significant (2p = 0.05 to 0.08) reductions in VLDL cholesterol, total triglyceride and VLDL triglycerides of 26%, 12% and 17% respectively. Large-scale trials are now required to determine whether reductions in lipid and lipoprotein concentrations confer a reduction in coronary heart disease morbidity and mortality in patients on dialysis.

Adolescent↗
PubMedDate not supplied

Fit of veneers made by CAD-CAM and platinum foil methods.

Veneers were fabricated by CEREC CAD-CAM and the platinum foil techniques for standardized preparations on 10 artificial teeth. Mesial preparation contacts were broken, but distal contacts remained intact. The veneers were cemented in a standardized manner to their teeth. The veneers and their attached cement were embedded in epoxy resin and sectioned twice gingivally-incisally and mesially-distally to produce eight sections. Three-way ANOVA disclosed that the main effects of fabrication method, section location, and measurement point location as well as all interaction terms significantly affected fit (P < 0.05). However, the difference in mean overall fit between the fabrication methods was too small to be of clinical importance. Restoration of the broken approximal contact did not compromise fit. Incisal margins had the greatest marginal openings. Surface measurement point locations were less well adapted than internal locations. Fit maps for CEREC and platinum foil veneers were strikingly similar.

Acrylates↗