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Biomedical subjects

R M Merion

Publications and source records attributed to R M Merion.

97 records · Page 6Linked to original sources
PubMed1985

Delayed acute rejection episodes in cyclosporine-treated renal transplant recipients.

Of 109 cyclosporine-treated cadaveric renal allograft recipients, 45 were free of acute rejection in the first 4 weeks after transplantation. Eleven of 45 (24%) subsequently had delayed, biopsy-proven first rejection episodes 34-61 days after grafting, often after discharge from the hospital. Delayed rejectors had significantly higher plasma creatinine levels at all times during the first posttransplant month than 34 nonrejectors. Trough serum cyclosporine levels were similar in the two groups, although by the 4th week oral cyclosporine dose was significantly lower in the delayed rejection group. Two-thirds of those patients who had serum creatinine levels greater than or equal to 260 mumol/l at 2 weeks and greater than or equal to 225 mumol/l at 3 weeks had a delayed acute rejection episode. Renal transplant recipients treated with cyclosporine who have serum creatinine levels at or above these levels should be aggressively worked up and closely followed for the development of delayed acute rejection.

Cyclosporins↗
PubMed1985

Measurements of reticuloendothelial system phagocytic activity in the rat after treatment with silica, liposomes, and cyclosporine.

Reticuloendothelial system phagocytosis was evaluated in vivo by the clearance and tissue distribution of 99mTc-albumin millimicrospheres in rats. Administration of i.p. silica 2 days prior to clearance measurement increased the half-life of millimicrospheres 24% compared with control animals (P less than 0.01). Impairment of phagocytic activity was maintained at 5 days to 22% over control values (P less than 0.01). Tissue distribution studies showed that liver uptake was reduced and splenic and pulmonary uptake was increased compared with control. Cyclosporine i.v. increased half-life by 14% 1 hr after administration )P = NS) and half-life returned to control values by 8 hr. Hepatosplenic shift was less marked than after silica treatment. Phospholipid liposomes i.v. produced prompt impairment of millimicrosphere clearance after 1 hr; half-life was prolonged 46% over control values (P less than 0.001 vs. control) and marked radiolabel shift to the spleen and lung was seen. Measurements done 18 hr after a dose of liposomes revealed an increase of 55% over control half-life (P less than 0.001). Liposomes appear to be potent, nontoxic--and, in some cases, reversible agents--for blockade of reticuloendothelial phagocytosis and examination of non-phagocytic reticuloendothelial functions. These results help to explain some of the results obtained in pancreatic islet grafting and suggest that phospholipid liposomes may be useful in this form of transplantation.

Animals↗
PubMed1984

Cyclosporine: five years' experience in cadaveric renal transplantation.

Using a retrospective analysis we compared 79 recipients of cadaveric renal allografts who were treated with cyclosporine as the sole initial immunosuppressant and 29 concurrent transplant recipients treated with conventional immunosuppressants. The cyclosporine-treated group had a slightly higher actuarial patient survival at four years (86 per cent v. 76 per cent). Actuarial graft survival at four years was 70 per cent in the cyclosporine group, as compared with 62 per cent in the conventionally immunosuppressed group. The incidence of acute rejection episodes was 62.1 per cent in the former and 65.5 per cent in the latter. Nephrotoxicity was managed either by reduction of the dose of cyclosporine or by conversion to conventional immunosuppression. Monitoring of trough serum levels of cyclosporine facilitated its administration. Serum creatinine levels have been higher in cyclosporine-treated patients with functioning grafts, but graft deterioration has not occurred after more than three years. Cyclosporine provides adequate immunosuppression for patients with renal allografts. At four years, the rates of patient and graft survival remain superior to those with conventional immunosuppression. In 41 per cent of patients the use of steroids was completely avoided. The longer-term results of this powerful immunosuppressive agent are not yet known.

Adolescent↗
PubMed1981

Selective management of penetrating neck trauma. Cost implications.

Many authors advocate mandatory surgical exploration for all patients with penetrating neck trauma, while other maintain that with careful diagnostic evaluation some patients safely can be spared an operation. From our hospitals, 65 cases of penetrating neck trauma were reviewed, 27 of which showed no mortality without operation. Surgical exploration of the neck showing no injury added $1,930 to the cost of hospitalization. Review of the surgical literature discloses that mortalities reported by authors advocating selective and mandatory exploration are similar. The incidence of missed significant injury is low among patients observed selectively. A management algorithm for the diagnostic evaluation and treatment of patients with penetrating neck trauma is advocated. All stable patients should undergo four-vessel angiography. Studies of the cervical esophagus may be performed. Patients with entirely normal diagnostic evaluations may be observed safely, sparing unnecesary operation.

Adolescent↗