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Excerpt
Dear Editor:
In the absence of the inferior mesenteric vein, Raper et al.1 inserted the Hickman catheter into the left gastric vein of patient 5 and encountered difficulties postoperatively. As an alternative, we would suggest the use of the jejunal tributaries of the superior mesenteric vein to gain access to the portal system. We have routinely used the jejunal tributaries for the infusion of purified pancreatic islets into the liver in both our primate long-term islet graft study2,3 and our clinical islet transplantation program. We have found it easy to thread the catheter into the superior mesenteric vein and up to the portal vein for the infusion of pancreatic islets and the monitoring of portal venous pressure.
Several investigators have reported bacterial and fungal contamination of the medium used to transport the pancreas procured for pancreatic islets isolation.4-6 Scharp et al.5 reported an 11% incidence of introducing microbial contaminants into the pancreatic islet preparation during the processing period. Despite using a class 100 laminar flow clean room and class 10 hoods for islet processing, the incidence was still 2.3%.5 The episode of rigors experienced by patient 3, as reported by Raper et al.,1 is most likely due to transient bacteremia and/or fungemia secondary to the infusion of contaminated cultured hepatocytes. It may not be possible to obtain a positive blood culture in these situations, as evidenced by the lack of reports of septicemia complicating the 117 islet transplants reported to the International Islet Transplant Registry during 1990-1993.7
In humans, reports of portal hypertension and hepatic infarction following infusion of islet tissue only occurred when a large volume (18 to 70 ml) of nonpurified pancreatic digest of both exocrine and endocrine tissue was embolized into the portal venous system.8-10 Transplantation of purified pancreatic islet tissue has not been associated with portal vein thrombosis,11,12 which certainly is a reflection of the infusion of a small amount of small sized particles into the portal venous system. Infusion of 24.55 ml of hepatocytes (a hepatocyte is a polyglonal cell of ∼25 μm in diameter13; assuming the hepatocyte is a sphere of 25 μm in diameter, the volume of 3 × 109 cells = 4/3 × 22/7 × (25/2)3 × (10−4)3 × 3 × 109 ml) may temporarily raise portal pressure, but its small size of 25 μm, compared to a size of 150 μm for an islet equivalent,14 should not pose the threat of a significant embolus. The presence of a catheter may potentially be a more worrying precipitating factor for thrombosis.
