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Biomedical subjects

R V Perez

Publications and source records attributed to R V Perez.

29 records · Page 2Linked to original sources

Lessons learned and future hopes: three thousand renal transplants at the University of Minnesota.

1. The experience of 3,183 transplants between June 7, 1963 and September 30, 1990 at the University of Minnesota was reviewed. 2. Patients were divided into 4 historical periods-each era was associated with improved outcome. 3. As results have improved, the proportion of patients less than 5 years old and the proportion greater than 50 years old have increased. Type I diabetes has become the most common cause of renal failure in patients transplanted here. 4. The most important variable leading to improved outcome was donor source. Both HLA-identical and HLA-nonidentical LRD transplants have better outcome than CAD transplants (p less than 0.0001). 5. Multivariate analyses were done to determine risk factors for survival: a) in the first year, and b) in subsequent years. In the first year, age greater than 50, diabetes, and retransplantation had an adverse affect whereas LRDs and CsA immunosuppression were beneficial. Similar factors affected survival after the first year. HLA mismatch had no impact. 6. When death with graft function was excluded, diabetes and age greater than 50 were no longer risk factors, suggesting that the excess graft loss in these groups was due to patient death. 7. Chronic rejection and death with function remain the predominant causes of graft loss. 8. As protocols have evolved, results have improved, and previously "high-risk" patients are being successfully transplanted. Future efforts should be directed at decreasing graft loss from rejection and death with function.

Adult↗

Augmentation of donor-specific transfusion and cyclosporine effects with dietary linoleic acid.

Increased prostaglandin production is a possible mechanism for the immunosuppressive effects of both cyclosporine and blood transfusions. Therefore, dietary supplementation with linoleic acid, a prostaglandin precursor, combined with either modality could act synergistically. Intraabdominal cardiac allografts were performed from Buffalo rat donors to Lewis recipients. Transplant recipients received a single donor-specific transfusion, low-dose cyclosporine (CsA, 1 mg/kd/d x 7 days), dietary supplementation with linoleic acid (LA, 16% of total calories) or a combination of the three modalities. CsA, DST or LA alone significantly prolonged allograft survival. Both CsA and LA acted synergistically with DST in further prolongation of survival--however, animals receiving all three modalities achieved 100% long-term survival. Augmentation of transfusion- and cyclosporine-induced immunosuppression with dietary prostaglandin precursor is possible.

Animals↗

Immunoregulation of transfusion-induced immunosuppression with inhibitors of the arachidonic acid metabolism.

To further define the role of arachidonic acid (AA) metabolites in transfusion-induced immunosuppression (TII), the effects of pharmacological manipulation of AA metabolism were examined in a rodent model. If the prostaglandins of the E series are mediators of TII, as has been recently hypothesized, then inhibition of cyclooxygenase (indomethacin) should abrogate whereas inhibition of lipoxygenase (nordihydroguaiaretic acid [NDGA]), or thromboxane synthetase (4-63557A) could potentiate the transfusion effect. Lewis rats received donor-specific transfusions from Buffalo rats in conjunction with one of the above inhibitors. Two weeks later they received intraabdominal Buffalo heart allografts or were used for one-way mixed lymphocyte reactions. Cyclooxygenase inhibition partially abrogated TII with shortened cardiac allograft survival. Lipoxygenase inhibition augmented TII, with depression of MLR and prolongation of allograft survival. Thromboxane synthetase inhibition had no effect. These results indicate that AA metabolites play a role in TII, and that immunoregulation via pharmacological manipulation of AA metabolism is possible.

Adjuvants, Immunologic↗

Dietary immunoregulation of transfusion-induced immunosuppression.

Dietary supplementation with fatty acids was carried out to examine whether the type and timing of dietary manipulation would have an effect on transfusion-induced immunosuppression in a rat cardiac transplant model. Linoleic acid (LA), oleic acid (OA), and fish oil (FO) were used because of their different effects on arachidonic acid (AA) metabolism. Pretransplant inhibition of AA metabolism (OA) shortened graft survival when compared with water-fed controls. Posttransplant LA (AA precursor) significantly prolonged graft survival. Pre- and posttransplant supplementation of LA and OA resulted in even more prolongation and shortening of graft survival, respectively. These findings suggest that transfusion-induced immunosuppression is partially mediated by AA metabolites, which are necessary for the pretransplant induction and posttransplant maintenance of the suppressed state. Dietary immunoregulation of transfusion induced immunosuppression is possible. The timing of dietary intervention and type of lipid supplementation is important in regulation of the immune response.

Adjuvants, Immunologic↗

The effect of donor specific transfusions and dietary fatty acids on rat cardiac allograft survival.

A rat heterotopic cardiac transplant model was used to study the effect of dietary lipids on the immune response. Animals receiving linoleic acid (LA), oleic acid (OA), and fish oil (FO) enriched diets showed significant prolongation of allograft survival when compared to the control diet fed animals. When LA was given to animals who had received a single donor specific transfusion (DST) augmentation of the beneficial DST effect was observed, while the OA and FO fed groups showed no differences from control DST animals. Dietary regulation of the immune response, possibly through manipulation of arachidonic acid metabolism, is implied.

Animals↗