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Biomedical subjects

R M Merion

Publications and source records attributed to R M Merion.

At least 91 records · Page 5Linked to original sources
PubMed1989

The hepatic artery in liver transplantation.

Hepatic artery complications after liver transplantation are uncommon, but represent an important cause of morbidity and mortality. In addition, these complications tax an already limited supply of donor organs because of the frequent need for retransplantation in this group of patients. In this study, we examined the incidence of hepatic arterial anomalies in donors and recipients of orthotopic liver transplants, focusing on the techniques that are available for hepatic arterial reconstruction and on the occurrence of hepatic arterial complications. A total of 77 liver transplants were carried out in 68 patients. Standard recipient anatomy was present in 60 of 68 patients (88%). Anomalous vessels were identified in eight patients (12%), including six cases of replaced right hepatic artery (9%) and two cases of replaced left hepatic artery (3%). Donor liver arterial anatomy was standard in 62 cases (80%). Anomalous arterial supply was identified in 15 of 77 donor livers (20%), including replaced left hepatic artery in nine (12%) and replaced right hepatic artery in six (8%). A variety of methods were used to manage the anomalous vessels. There was one hepatic artery pseudoaneurysm, three cases of hepatic artery thrombosis (4%), and one patient developed a dissection of the native celiac axis. In primary transplants, utilization of the recipient's proper hepatic artery was associated with a significantly higher risk of hepatic artery thrombosis (P less than 0.04) when compared with the common hepatic artery or the branch patch technique. Use of a Carrel patch on the donor artery was associated with a significantly reduced incidence of hepatic artery thrombosis (P less than 0.0003). For retransplantation, it is recommended that a more proximal recipient anastomotic site be chosen. An innovative method is described that provides increased length of the donor arterial supply without the use of an arterial graft.

Hepatic Artery↗
PubMed1989

Liver transplantation at the University of Michigan.

Liver transplantation is a highly successful therapy for liver diseases that were previously debilitating and often fatal within a few months. One-year actuarial patient survival for our first 162 patients is 74.7%. Our results have improved since the inception of the program despite the fact that the indications have been extended to higher risk patients such as those with fulminating hepatitis or thrombosed portal veins. The prognosis following transplantation for each specific indication needs to be defined, especially for hepatitis, alcoholic cirrhosis and individual cancers. We believe that a more conservative approach to immunosuppression, close attention to intravenous and enteral nutrition, and aggressive treatment of complications (including prompt reoperation when indicated) have been important improvements in our management practices.

Adolescent↗
PubMed1989

Pancreas transplantation: an immunohistochemical analysis of pancreatic hormones and HLA-DR expression.

The immunohistochemical features of pancreatic grafts in eight patients with pancreatic transplants were analyzed and compared with pancreases from five patients with chronic pancreatitis and with three pancreatic tissues without histological abnormalities. There was a significant increase in glucagon producing cells in patients with transplanted pancreases compared with those with chronic pancreatitis (P less than 0.05). A significant decline in insulin-producing cells was seen in the transplanted pancreases with rejection in comparison with normal pancreatic tissue. Immunohistochemical staining for HLA-DR (Ia) antigens revealed expression of HLA-DR by endothelial cells, mononuclear cells, and by some ductal epithelial cells, but not by the endocrine islet cells. These results suggest that significant changes in insulin and glucagon production occur in the transplanted pancreas with rejection and that HLA-DR is not expressed by islet cells during graft rejection or with chronic inflammation.

Adult↗
PubMed1989

Bile refeeding after liver transplantation and avoidance of intravenous cyclosporine.

Because absorption of cyclosporine (CyA) given orally immediately after liver transplantation is unreliable, the drug is usually given intravenously until external biliary drainage is discontinued. Intravenous CyA, however, is associated with serious side effects, making its use potentially hazardous. We report the results of a new strategy in which we used oral CyA exclusively and refed bile to enhance oral CyA absorption. Thirty-two liver transplant recipients with indwelling T tubes were studied. All were given sequential quadruple drug immunosuppression with antilymphoblast globulin, azathioprine, and steroids. Oral CyA and refeeding of bile was started when renal function was stable. By the second posttransplant week, satisfactory CyA levels were achieved, and antilymphoblast globulin therapy was stopped. There were significant associations between oral CyA dose and CyA level and between quantity of refed bile and CyA level (p less than 0.001). CyA dose and quantity of bile refed were covariates, however, and in multiple regression analysis, only the quantity of refed bile was significant (p = 0.001). CyA levels did not correlate with rejection. The incidence of rejection was 63%. At a mean follow-up of 9 months, 28/32 (88%) patients were alive, and actuarial 1-year patient survival was 84%. Current graft and renal function are excellent (serum bilirubin, 1.0 +/- 0.1 mg/dl; serum creatinine, 1.2 +/- 0.1 mg/dl). We conclude that intravenous CyA can be avoided in virtually all liver-transplant recipients by administration of oral CyA with bile in the early posttransplant period.

Administration, Oral↗
PubMed1988

Peripheral blood catalase in patients undergoing renal transplantation.

Oxygen free radicals are mediators of tissue injury and catalase is an enzyme which is involved in limiting this process. We examined peripheral blood catalase activity (PBCA) to assess its value as a marker in detecting tissue injury related to renal allograft rejection. Thirty-one consecutive recipients of kidney (n = 29) or simultaneous kidney/pancreas (n = 2) transplants and 10 normal volunteers were studied. Catalase activity, measured by the disk-flotation method, was expressed as Sigma units X 10(-3)/ml (SU/ml) of whole blood. Normal PBCA was determined to be greater than 76 SU/ml. Twenty-nine episodes of renal allograft rejection (diagnosed by clinical criteria +/- biopsy [79%]) were observed in 26 patients. PBCA (mean +/- SEM) was found to be low (64 +/- 1 SU/ml) in 28/29 episodes (chi 2 = 46.3, P less than 0.001), and the decrease (at least two consecutive daily catalase values less than 76 SU/ml) occurred 2 days prior to the clinical/biopsy diagnosis of rejection in 26/28 episodes. The sensitivity of PBCA as a discriminant of rejection was 97%, specificity was 96%, and test accuracy was 96%. PBCA less than 50 SU/ml on two or more occasions occurred in five cases and transplant nephrectomy was required in four of these because of uncontrollable rejection. Nine episodes of cyclosporine nephrotoxicity occurred in 7 patients and none of these episodes was associated with a decreased PBCA. Our data suggest that decreased PBCA is a sensitive and specific indicator of renal allograft rejection. PBCA remains normal during episodes of cyclosporine nephrotoxicity and therefore provides a rapid and inexpensive discriminant from allograft rejection.

Adolescent↗
PubMed1988

Extravesical ureteroneocystostomy in renal transplantation.

From October 1970 to January 1986, 808 patients underwent renal transplant ureteroneocystostomy by an extravesical technique. Complications related to the anastomosis and/or ureter were reviewed. There were 23 total complications, for an over-all urological complication rate of 2.8 per cent. Of these complications 17 were related to the ureteroneocystostomy, for an anastomotic complication rate of 2.1 per cent. Complications were almost universally repaired by another operation. Two patients died and 1 lost the allograft because of urological complications.

Anastomosis, Surgical↗
PubMed1988

Orthotopic liver transplantation totally corrects factor IX deficiency in hemophilia B.

Orthotopic liver transplantation has been performed for a growing range of liver-based inborn errors of metabolism. Previous authors have documented that liver transplantation can reverse the coagulation defect of hemophilia A. In this article we report total correction of factor IX deficiency in a patient with hemophilia B and blood product-related liver disease. Intraoperative bleeding was not excessive, and the donor liver produced normal amounts of factor IX immediately.

Adolescent↗
PubMed1988

Scintigraphic demonstration of accessory hepatic duct leak following liver transplantation.

Few noninvasive methods are available to diagnose complications following liver transplantation. Hepatobiliary scintigraphy can differentiate rejection from primary biliary complications such as obstruction or extravasation in patients with nonspecific clinical findings such as fever and rising liver function studies. In the following case report, an unexpected biliary leak from a recipient accessory hepatic duct was demonstrated by [99mTc] DISIDA scintigraphy following liver transplantation.

Adult↗
PubMed1987

Quantitative scintigraphy with deconvolutional analysis for the dynamic measurement of hepatic function.

A mathematical technique known as deconvolutional analysis was used to provide a critical and previously missing element in the computations required to quantitate hepatic function scintigraphically. This computer-assisted technique allowed for the determination of the time required, in minutes, of a labeled bilirubin analog (99mTc-disofenin) to enter the liver via blood and exit via bile. This interval was referred to as the mean transit time (MTT). The critical process provided for by deconvolution is the mathematical simulation of a bolus injection of tracer directly into the afferent blood supply of the liver. The raw data required for this simulation are obtained from the intravenous injection of labeled disofenin, a member of the HIDA family of radiopharmaceuticals. In this study, we perform experiments which document that the simulation process itself is accurate. We then calculate the MTT under a variety of experimental conditions involving progressive hepatic ischemia/reperfusion injury and correlate these results with the results of simultaneously performed BSP determinations and hepatic histology. The experimental group with the most pronounced histologic findings (necrosis, vacuolization, disorganization of hepatic cords) also have the most prolonged MTT and BSP half-life. However, both quantitative imaging and BSP testing are able to identify milder degrees of hepatic ischemic injury not reflected in the histologic evaluation. Quantitative imaging with deconvolutional analysis is a technique easily adaptable to the standard nuclear medicine minicomputer. It provides rapid results and appears to be a sensitive monitor of hepatic functional disturbances resulting from ischemia and reperfusion.

Animals↗
PubMed1987

Pediatric renal transplantation with an emphasis on the prognosis of patients with chronic renal insufficiency since infancy.

In this report recent experience with renal transplantation in 43 children who were 17 days to 16 years old was reviewed. One-year patient survival rate was 98%, and overall one-year graft survival rate was 68%. One-year graft survival rate was 73% for cyclosporine-treated patients and 78% for recipients of related donor kidneys. A subpopulation of patients affected with renal insufficiency since infancy was analyzed separately to evaluate the prognosis of these patients, who have previously been reported to be a high risk for permanent neurologic, developmental, and growth retardation. All 16 such patients underwent transplantation. Gross motor delay that was noted in 31% of patients before surgery resolved in all patients after transplantation. No evidence of severe developmental delay was noted after transplant and seven of 11 patients with successful transplants had evidence of catch-up growth. Overall renal transplantation is a safe and effective procedure for children with renal failure, and even the patients at highest risk for growth and developmental failure caused by renal insufficiency show potential for rehabilitation after transplantation.

Adolescent↗
PubMed1986

Detrimental effects of four hours of cold storage on porcine pancreaticoduodenal transplantation.

Transplantation of the pancreaticoduodenal allograft (PDA) has recently been advocated as a technique that is superior to the use of the segmental allograft. However, the effect of simple cold storage preservation on the PDA has not been studied. We investigated the effect of 24 and 4 hours of cold storage in Eurocollins solution on porcine PDA function after transplantation in pancreatectomized pigs. A regimen of cyclosporine and prednisone was used, which prevented rejection for at least 28 days after transplantation. Cold storage preservation for 24 hours uniformly resulted in PDA failure. Compared with recipients of immediately transplanted PDA, recipients of PDA cold stored for 4 hours had marked plasma hyperamylasemia (10,000 U/L versus 1932 U/L), relative glucose intolerance (K value -2.15 versus -2.66), hypoinsulinemia (peak immunoreactive insulin 11.0 microU/ml versus 34.7 microU/ml), and an abnormal pattern of insulin secretion as demonstrated with intravenous glucose tolerance testing. There was also a higher incidence of technical complications in the group transplanted with cold-stored PDAs. Our results suggest that there is a detrimental effect on porcine PDA function after only 4 hours of cold storage in Eurocollins solution.

Amylases↗