1954

1954 marked the most important year for modern transplantation. It represented the date in which the first successful live kidney transplant was performed by the devoted group of Joseph Murray, Hartwell Harrison, and their Peter Bent Brigham associates in Boston. Intense preparation and careful analysis was required for a long time to arrive at the resounding success manifested in the case of the Herrick twin brothers. Years later, only the discovery of chemical immunosuppression such as azathioprine and the use of radiation therapy permitted occasional good results in kidney transplantation. Great contributors of this period included Elion and Hitchings, Calne and Zukowski, Woodruff, Goodwin, and many others. In a few more years, the use of steroids and an antilymphocyte preparation by the committed team of Tom Starzl from Colorado improved the opportunities for patient outcome. The latter part of the 1960s witnessed the maturation of the Minnesota program with the arrival of John Najarian from California. The 1970s introduced different morbidity and mortality associated with immunosuppressive treatment, and required adjustments in patient management were necessary. New advances were to come in years ahead.

John Collins Warren: Master educator and pioneer surgeon of ether fame

John Collins Warren (1778-1856) represented the apex of surgery and medicine of the first half of nineteenth century Boston. Educated at Harvard College where he obtained a Bachelor of Arts in 1797, he contemplated the idea of a business career prior to setting sail for a traditional medical education at Europe's finest universities. From 1799 to 1802, he attended prestigious medical and surgical lectures in London, Edinburgh, and Paris. Warren received an honorary MD from Scotland's St. Andrews University in 1802. He then returned to Boston and joined his father's practice. In 1815, he followed his accomplished father as the Hersey Professor of Anatomy and Surgery at Harvard Medical School. He held this position with great distinction until 1847 when he retired as professor emeritus. From 1816 to 1819 he served as Harvard Medical School dean and received an honorary medical degree at the end of his term.John Collins Warren had numerous surgical accomplishments during his illustrious career. Clinically, he was active and varied in his practice, operating on strangulated hernias, tumors, and cataracts, in addition to performing vascular surgery and amputations. He published many articles and books of widespread circulation. Professor Warren also performed the first reported case of ether anesthesia administered by William T. Morton on October 16, 1846. Outside the operating theatre, Doctor Warren and his colleagues were revered for founding the Massachusetts General Hospital in 1821, and years before, in 1812, Warren and his associates established the New England Journal of Medicine and Surgery. In light of his varied contributions, John Collins Warren is remembered as a dedicated and innovative surgeon, as well as a committed medical educator, able administrator and effective leader.

Tacrolimus (FK506) down-regulates free radical tissue levels, serum cytokines, and neutrophil infiltration after severe liver ischemia

BACKGROUND

Liver ischemia and reperfusion injury is associated with activation of multiple inflammatory pathways, including free radicals, cytokines, and neutrophil-mediated tissue damage among others. Tacrolimus (FK506) has shown important regulatory effects on some inflammatory pathways, such as cytokines, neutrophils, and adhesion molecules. In this study, we explored a new potential protective mechanism for tacrolimus in the liver inflammatory response after ischemia and reperfusion, specifically its effect on liver tissue free radicals.

METHODS

Total hepatic ischemia was produced in the rat for 90 min with an extracorporeal portosystemic shunt. Animals (n=96) were divided into four groups: group 1 comprised normal rats for reference values; group 2 comprised sham operated rats; in group 3, ischemic control rats received only the vehicle; and the experimental treatment group, group 4, received tacrolimus at a dose of 0.3 mg/kg, 4 hr before ischemia. Animal survival was followed up to 7 days. Liver function tests were performed and liver tissue free radicals and myeloperoxidase, serum cytokines (interleukin 1, tumor necrosis factor-alpha), and liver histology were measured 4 hr after reperfusion.

RESULTS

Seven-day survival was significantly improved from only 20% in the control group to 55% in the tacrolimus group (P<0.01). Liver function tests, histology, and myeloperoxidase tissue values were significantly improved (P<0.05) with tacrolimus pretreatment. Furthermore, a significant (P<0.05) down-regulation of serum cytokines and liver tissue free radicals was observed.

CONCLUSIONS

These data indicate a new and different protective mechanism for FK506 in regard to its ability to down-regulate free radical levels in livers subjected to severe ischemia and reperfusion. Tacrolimus, also confirmed to be a potent suppressor of the cytokine response, specifically interleukin 1 and tumor necrosis, decreased neutrophil tissue migration as well.

21-Aminosteroids block neutrophil infiltration and provide liver protection independent of NO2-/NO3- levels

21-Aminosteroids are antioxidant compounds that prevent iron-dependent lipid peroxidation and improve cell viability. In this work we attempt to define the role of 21-aminosteroids in liver ischemia and reperfusion and assess their possible mode of action, specifically their effect on neutrophil infiltration and nitrite/nitrate levels. Total liver ischemia for 90 min was produced in the rat with the use of a portosystemic shunt. Three groups of animals were studied. One group received the 21-aminosteroid U-74389G (10 mg/ kg) divided into two equal doses 10 min prior to ischemia (7 mg/kg) and 10 min before reperfusion (3 mg/ kg). The two other groups included the sham and the control animals. We studied survival at 7 days and serum liver enzymes, liver myeloperoxidase, plasma nitrites, nitrates, and liver histology at 6 hr postreperfusion. Animal survival improved from 13% in the ischemic control to 52% in the lazaroid treated group (P < 0.05). We observed significant improvements in liver function tests, liver myeloperoxidase levels, as well as in the liver histology (P < 0.05). We could not find statistical difference in plasma nitrite/nitrate (P > 0.1). The 21-aminosteroids significantly improved animal survival after total liver ischemia, through a mechanism that includes blocking neutrophil infiltration which is independent from nitrite/nitrate levels.

Role of nitric oxide in ischemia/reperfusion of the rat kidney

This work studies the role that nitric oxide (NO) plays in ischemia/reperfusion (I/R) of the rat kidney. Sprague-Dawley rats, weighing 250-300 g, were subjected to 75 min of warm ischemia and contralateral nephrectomy. The animals were divided into six groups (n = 12 per group): ischemic control (IC) with normal saline, L-NG-mono-methyl-arginine (L-NMMA) 50 mg/kg, L-arginine (L-Arg) 300 mg/kg, Na-nitroprusside (Na-NP) 2.5 mg/kg, the combination of L-NMMA+Na-NP at the doses used before, and the sham group. All animals received the drug intravenously 60 min prior to ischemia. Survival was evaluated at seven days. Renal damage was assessed by kidney function tests (serum creatinine and blood urea nitrogen) and light histology. Lipid peroxidation was measured in renal tissue using the thiobarbituric acid assay. Significantly better survival was seen in the Na-NP group, as compared to the rest of the study. Serum creatinine at 24 and 48 hr showed a significant difference between the Na-NP group and the other groups. Histological damage was minimal in the Na-NP group. Clearly, the Na-NP had the most beneficial effect in survival and histological structure. Lipid peroxidation was significantly different, with the lower levels seen in the L-NMMA group and the higher levels in the Na-NP group. In base to these results, we conclude that exogenous NO has a beneficial and protective effect of the ischemically damaged rat kidney. This protection is independent of lipid peroxidation. Endogenous NO production does not play a role in I/R injury in our model.