Search PubMed⌕ Search

Biomedical subjects

R W Busuttil

Publications and source records attributed to R W Busuttil.

At least 145 records · Page 8Linked to original sources
PubMed1995

Perforin and granzyme B. Cytolytic proteins up-regulated during rejection of rat small intestine allografts.

Perforin and granzyme B are 2 cytolytic proteins specific to activated killer cells, particularly CTL. We have studied the mRNA expression of these 2 proteins by a reverse transcriptase polymerase chain reaction method in a unidirectional model of rat small intestine transplant rejection. The allograft group consisted of Lewis x Brown Norway F1 donors into Lewis recipients. The isograft controls were Lewis donors into Lewis recipients. Grafts were placed heterotopically and no immunosuppression was given. Five animals in each group were killed at postoperative days (POD) 3, 5, 7, 8, 9, 10, 12, and 14. mRNA was extracted and a semiquantitative reverse transcriptase polymerase chain reaction was performed. For the semiquantitative analysis, we compared scintillation counts from excised bands. Results were expressed as a percent activity compared with beta-actin. From the same tissue samples, a histologic evaluation was made and rejection was graded according to severity. The isograft controls showed no evidence of histologic rejection and a very low expression of mRNA for perforin and granzyme B from POD 3-14. In contrast, the allograft group began to show histologic evidence of mild rejection on POD 5. By day 7, rejection was moderately severe and associated with a significant up-regulation of perforin and granzyme B in the allografts compared with the controls (P < 0.01), which persisted through POD 14. Peak expression for perforin and granzyme B was on POD 10 and 8, respectively. We conclude that the up-regulation of perforin and granzyme B in rat small intestine transplant allografts is a useful marker of clinically important rejection.

Animals↗
PubMed1995

FK506 (tacrolimus) compared with cyclosporine for primary immunosuppression after pediatric liver transplantation. Results from the U.S. Multicenter Trial.

We report on the efficacy and safety of FK506 (tacrolimus) compared with a cyclosporine (CsA)-based immunosuppressive regimen after 1 year of treatment in pediatric liver allograft recipients (< 12 years) participating in a multicenter U.S. randomized trial. Patients received either FK506 or CsA as primary immunosuppression following a first ABO-compatible liver transplant. Intravenous FK506 was initiated at 0.1 mg/kg per day, followed by oral FK506 beginning at 0.3 mg/kg per day. The dose was adjusted to maintain plasma trough levels of 0.5-2.0 ng/ml. The CsA group was treated according to each center's usual protocol. Both groups received the same initial doses of corticosteroids. All rejection episodes were biopsy-proven and a standardized algorithm was adopted for the treatment of rejection. Thirty patients were randomized to the FK506 group and 20 to the CsA group. After twelve months of follow-up 20 patients remained in the FK506 group and 13 in the CsA group. Patient survivals were 80% and graft survival 70% in the FK506 group compared with 81% and 71% respectively, in the CsA group. 48% of the FK506 group remained rejection-free compared with 21% of the CsA group, and 79% of FK506-treated patients did not require OKT3 compared with 68% of CsA treated patients. The cumulative corticosteroid dose was less at each time point throughout the first year in the FK506 group. The incidence of serious and minor infections was similar in both groups. Nephrotoxicity, neurotoxicity, and gastrointestinal disturbances were the major toxicities reported. Differences did not reach statistical significance between the two groups although major neurologic events, diarrhea and dyspepsia were more often reported in the FK506 group. There was no difference in mean serum creatinine at 12 months between the two groups. There was a tendency toward lower mean serum cholesterol in the FK506 group. There was no hirsuitism in the FK506 group compared with a 30% incidence in the CsA group. In conclusion, compared with CsA, there is a trend toward less rejection in FK506-treated pediatric allograft recipients, while both drugs have a similar spectrum of side effects.

Adrenal Cortex Hormones↗
PubMed1995

Efficient gene transfer to pancreatic islets mediated by adenoviral vectors.

Genetic manipulation of pancreatic islets before transplantation has the potential to alter cellular immunity as well as islet function. The purpose of this study was to examine the feasibility of gene transfer to islets, using replication-defective adenoviral vectors. Newborn mouse islets were infected with AdHCMVsp1LacZ vector encoding Escherichia coli beta-galactosidase (beta-gal). Islets were cocultured with vector, at virus-to-target cell ratios of 10:1, for 1 hr. Gene transfer was assessed by specific histochemical stain for beta-gal (X-gal). Islet DNA and RNA were analyzed by Southern and PCR for beta-gal and adeno sequences, and recombinant protein production by western and ONPG assays. Islet integrity after gene transfer was assessed by static incubations and transplantation to nondiabetic and to diabetic mice. Southern analysis and PCR confirmed the presence of E coli beta-galactosidase and the E4 adeno DNA in infected islets, but not in controls. Reverse-transcription PCR and western analysis demonstrated expression and protein production of inserted E coli beta-galactosidase, but not E4 message. Insulin release in response to static incubations was unimpaired in infected islets. Syngeneic islet grafts stained positively for insulin for up to 7 days. Transplanted, genetically manipulated islets functioned similarly to control islets in reversing murine drug-induced diabetes. Thus, gene transfer into islets can be accomplished using adenovirus-based vectors. The capacity of this virus to infect non-dividing cells allows insertion of cDNA into pancreatic islets, with potential application to the transplant setting.

Adenoviruses, Human↗
PubMed1995

Transjugular intrahepatic portosystemic shunts: impact on liver transplantation.

This study was designed to evaluate the impact of transjugular intrahepatic portosystemic shunts (TIPS) on liver transplantation. Historically, the complications of portal hypertension have been temporized with sclerotherapy or surgical portosystemic shunts. In patients whose liver disease progressed, liver transplantation has been used as definitive treatment. More recently, TIPS is being used increasingly for the management of the complications of portal hypertension. The impact of this new modality on liver transplantation is evaluated. The records of 135 adult patients undergoing liver transplantation at University of California at Los Angeles between October 1992 and June 1993 were reviewed. Twenty-three patients had received at least one shunt before transplantation. The TIPS procedure complicated the operative course of 5 patients (22%). In 2 patients the TIPS had been placed cephalad, making placement of the suprahepatic vena caval clamp difficult. In 2 other patients, the shunt had been placed caudad, extending in the extrahepatic portal vein. In all 4 of these patients, the intima had been damaged at the area of the subsequent anastomosis. In the fifth patient, the bile duct had been perforated during the placement of the shunt, causing diffuse bile peritonitis, which was sterile, and the transplantation was performed. The average intraoperative blood loss for these 5 patients was 13 U. There was no significant decrease in intraoperative blood loss for all patients with a TIPS when compared with 112 adults who underwent liver transplantation during the same period (11 U v 10.5 U). The TIPS stent did not improve objective intraoperative parameters as compared with liver transplant recipients without TIPS. The indications for TIPS must be carefully weighed against the potential risks of increasing the technical difficulty of the transplantation and jeopardizing the candidacy of some liver transplantation candidates. Liver transplantation is not facilitated by TIPS insertion and therefore should not be used to justify TIPS placement.

Adult↗
PubMed1995

The inhibitor cytokine interleukin-1 receptor antagonist synergistically augments cyclosporine immunosuppression in a rat cardiac allograft model.

Interleukin-1 receptor antagonist (IL-1ra) competes with IL-1 for binding of the IL-1 receptor, but does not elicit a cellular immune response. This study was designed to evaluate the effectiveness of IL-1ra in the immune and inflammatory responses to rat heart allografts. Experimental design was as follows: Group I HTx was syngeneic, BN to BN. The remaining groups were DA (RT 1a) to BN (RT 1n) allogeneic HTx. Group II was transplanted without immunosuppression. Group III received a low-dose IL-1ra regimen via osmotic pump into the peritoneum. Group IV recipients were similarly treated with a higher dose IL-1ra regimen. Group V rats received subtherapeutic cyclosporine (CsA) therapy while Group VI was treated with both CsA and low-dose IL-1ra. Group I rats survived indefinitely. Group II rats rejected their grafts at 5.33 +/- 1.37 days. Group III grafts survived for 7.16 +/- 0.48 days, and Group IV grafts for 8.16 +/- 0.75 days, both significantly longer than in Group II (P < 0.01). Group V animals treated with low-dose CsA had graft survival of 7.7 +/- 1.6 days, but combined therapy with CsA and IL-1ra in Group VI yielded significantly prolonged graft survival of 17.2 +/- 1.3 days (P < 0.0001). Histologic examination in treated recipients revealed delayed appearance of mononuclear cell infiltration. IL-1ra-treated recipients all demonstrated significantly reduced numbers of graft-infiltrating leukocytes; all phenotype subsets were equally affected. This study demonstrates the effectiveness of IL-1ra, in combination with low-dose CsA, in reducing the inflammatory response and rejection in the transplant setting.

Animals↗
PubMed1995

Transduction of hepatic allografts achieves local levels of viral IL-10 which suppress alloreactivity in vitro.

The application of gene therapy in transplantation might be targeted at immunoregulation within the donor graft. Viral IL-10 (vIL-10) down-regulates antigen presenting cells (APC) and effector functions in in vitro and in vivo models of alloreactivity. In the current study, we have constructed a replication-defective adenovirus bearing the cDNA encoding viral IL-10 and examined the level and chronicity of its expression in rat liver allografts up to 7 days after orthotopic transplantation. The results demonstrate that liver allografts may be efficiently transfected with adenovirus expressing viral IL-10. Detection of the recombinant viral cytokine was limited to the allograft without measurable levels in peripheral blood. In parallel, the effect of vIL-10 on mixed leukocyte reaction is also assessed using peripheral blood lymphocytes obtained from naive donor and recipient animals. Equivalent levels of viral IL-10 (5-10 ng/ml) achieved after adenovirus-mediated gene transfer suppress the in vitro alloreactivity of peripheral blood lymphocytes up to 70%. Adenovirus-mediated gene transfer of viral IL-10 offers the promise of effectively and favorably altering the alloreactive immune response.

Adenoviridae↗
PubMed1995

Hepatic function is preserved following liver-directed, adenovirus-mediated gene transfer.

Inherited and acquired disorders of the liver are attractive targets for gene therapy. Hepatic cells are susceptible targets for shuttle vectors because of a diversity of protein and viral receptors and accessibility of a selective afferent blood supply. Preservation of existing hepatic cell integrity and metabolic function is of paramount importance for successful whole animal gene therapy trials. In this report, we examine hepatic cell function and integrity following adenovirus-mediated reporter gene transfer to the liver in vivo. E1-deleted, replication-defective adenovectors encoding the LacZ gene driven by the human CMV promoter were delivered to the liver by isolated portal perfusion. The gene transfer rate, as determined by specific histochemical staining, approached 30% with recombinant protein detectable by Western blot throughout the course of study. Hepatic cell integrity as assessed by histology and hepatic enzyme profile (serum aspartate aminotransferase, gamma-glutamyl transpeptidase) demonstrated normal cellular architecture and no significant difference between transfected liver and controls. Hepatic synthetic and metabolic function, as determined by albumin levels, prothrombin time, and bilirubin, were similar between the two study groups. This study demonstrates that efficient adenovirus-mediated gene transfer and expression in the rat liver do not compromise hepatic cell metabolism and integrity.

Adenoviridae↗
PubMed1995

Reduced-size grafts--the solution for hepatic artery thrombosis after pediatric liver transplantation?

Reduced-size liver grafts (RSG) were developed to alleviate the donor shortage for pediatric patients, particularly those requiring emergency transplantation. In theory, the large size of the hepatic artery available for anastomosis from RSG, as opposed to whole pediatric grafts, is less likely to lead to hepatic artery thrombosis (HAT). Therefore, the authors reviewed their experience with HAT, comparing RSG and whole-liver grafts in pediatric patients undergoing emergency liver transplantation. Despite the severity of illness of the recipients (UNOS status IV), and the intrinsic damage to the graft during reduction, HAT was not seen after RSG for emergency pediatric transplantation. In contrast, 29% of pediatric recipients who received whole grafts for emergency transplantation had HAT. RSG is a safe alternative to whole-liver grafts for pediatric liver transplantation, and may reduce the incidence of HAT.

Adolescent↗
PubMed1995

Evaluation, operative management, and outcome after liver transplantation in children with biliary atresia and situs inversus.

INTRODUCTION: Biliary atresia, a common indication for liver transplantation, can be associated with situs inversus. Our experience with liver transplantation in children (n = 6) was reviewed retrospectively. PATIENTS AND METHODS: Preoperative duplex sonography, computerized tomography, and visceral angiography were obtained. Vascular anomalies identified included preduodenal portal vein (6/6), interrupted inferior vena cava (5/6), and aberrant hepatic artery (4/6). RESULTS: The liver graft was placed in a midline position. Venous continuity was achieved by donor suprahepatic inferior vena cava to recipient hepatic cloaca and direct end-to-end portal anastomosis. The donor infrahepatic inferior vena cava was oversewn. Arterial continuity was restored using either a direct branch-patch anastomosis (3/6) or a supraceliac aortic interposition graft (3/6). In retrospect, preoperative diagnostic work-up was noncontributory and outcome was not complicated by pre-existing situs inversus. CONCLUSION: Situs inversus in liver recipients requires operative technical modifications, but does not change outcome. Furthermore, extensive preoperative work-up should be avoided.

Biliary Atresia↗
PubMed1995

The treatment of intractable rejection with tacrolimus (FK506) in pediatric liver transplant recipients.

We report our experience in 17 pediatric orthotopic liver transplant (OLT) patients converted from cyclosporine (CsA) to FK506 for intractable acute and chronic rejection. FK506 was initiated orally at a dose of 0.3 mg/kg/day in most patients; the dose was then adjusted to achieve serum levels of 0.5-1.5 ng/ml. Azathioprine was discontinued and low-dose prednisone maintained. The median time between liver transplantation and FK506 conversion was 41 months. Patients have been treated for an average of 14.8 +/- 9.6 months. Six patients were converted for acute rejection and 11 for chronic rejection, i.e., vanishing bile duct syndrome (VBDS). After FK506 conversion, the actual patient and graft survival was 88% and 82%, respectively, in the group as a whole. Two patients died, one of chronic active hepatitis C and the other of lymphoma. Three patients, all with VBDS, did not respond to FK506 and therefore required retransplantation. The serum bilirubin is currently normal in 14 patients and the serum transaminases < 100 IU/ml in 12. The mean bilirubin pre-FK506 of patients successfully converted to FK506 was 4.2 mg/dl compared to 11.8 mg/dl in patients who failed conversion. Major complications included nephrotoxicity, neurotoxicity, and lymphoma. The mean glomerular filtration rate (GFR) of 97 +/- 29 mls/min/1.73m2 prior to FK506 conversion dropped to 51 +/- 20 mls/min/1.73m2 (p = 0.0001) after a mean of 13.6 months of FK506 therapy. Three patients have developed B-cell lymphomas; two of them responded to decreased immunosuppression and one died. We conclude that intractable liver graft rejection in children is most successfully reversed if FK506 is instituted before cholestasis becomes pronounced.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

The value of portal vein pulsatility on duplex sonograms as a sign of portal hypertension in children with liver disease.

OBJECTIVE: The purpose of this study was to determine the significance of portal vein pulsatility on duplex Doppler waveforms in children with end-stage hepatic failure undergoing liver transplantation. SUBJECTS AND METHODS: Thirty-eight children with end-stage hepatic decompensation were examined with color-assisted spectral Doppler waveform analysis of the hepatic artery and the portal vein. Correlation was made with age, duration of illness, clinical and pathologic diagnosis, and presence of portal hypertension. Findings were compared with those for six patients with acute viral hepatitis and 12 healthy control subjects. RESULTS: Portal vein pulsatility was noted in all 36 patients in whom portal vein flow was detected by Doppler imaging. The majority of these (34) had clinical or sonographic evidence of portal hypertension. In two patients, no portal vein flow was identified in the liver hilum; both had a large portosystemic shunt through collaterals or surgical graft. Significantly increased pulsatility of the hepatic artery waveform (resistive index [RI] = 0.89 +/- 0.15, p < .0001) was seen in patients with end-stage liver disease. In contrast, no portal vein pulsatility and normal hepatic artery pulsatility (RI = 0.60 +/- 0.11) was noted in all patients with acute hepatitis and control subjects. CONCLUSION: Portal vein waveform pulsatility is 94% sensitive and 90% specific for portal hypertension in end-stage liver disease.

Acute Disease↗
PubMed1995

Role of liver transplantation in patients with hepatitis B infection.

Liver transplantation is currently considered definitive therapy for end-stage liver disease (1-4). The hepatitis B virus (HBV) affects a large group of candidates for liver transplantation (1-4), however, liver transplantation for HBV is associated with unique and serious problems due to post-transplant predisposition for HBV re-infection of the allograft (5-10, 12-14). Patients with actively replicating HBV infection, as demonstrated by positive pre-transplant hepatitis surface antigen (HBsAg), hepatitis e antigen (HBeAg), and HBV-DNA, patients retransplanted for HBV infection, patients not receiving long term hepatitis B immunoglobulin (HBIG) therapy (5-10, 12, 14), and patients of Asian descent (15), appear to be most likely to experience clinically significant recurrent hepatitis (2, 3, 6-14). Recurrent HBV can produce acute or chronic liver disease leading to graft failure, retransplantation, or death (2, 3, 5, 13, 14). For these reasons, liver transplantation for HBV remains controversial. In this review, we describe the proposed mechanisms, predisposing factors, and clinical presentation associated with HBV recurrence in liver allograft recipients. We also discuss current and potential methods of prevention of HBV infection following liver transplantation.

Hepatitis B↗
PubMed1994

The correlation of intragraft cytokine expression with rejection in rat small intestine transplantation.

Rejection continues to be a major cause of graft loss in small intestine transplantation (SIT). We have studied, by semiquantitative reverse transcriptase PCR (rtPCR), the intragraft expression of cytokines relevant to rejection in a rat model. Heterotopic SIT grafts were performed from Lewis x Brown Norway F1 donors into Lewis recipients. The isograft control was Lewis into Lewis. Five animals in each isograft and allograft group were sacrificed on POD 3, 5, 7, 8, 9, 10, 12, and 14. mRNA was isolated from portions of the terminal ileum and rtPCR performed to amplify message for interleukin-2 (IL-2), IL-2 receptor (IL-2R), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma). Semiquantitative analysis was performed using 32P radionuclide incorporation and scintillation counting. The results were expressed as percent activity compared with beta-actin. Histologic correlation with cytokine expression was made. On POD 3 after SIT there was no evidence of rejection by histology and all cytokines studied showed no difference between the isograft and the allograft. On POD 5 the first evidence of mild rejection was seen on histology and IL-6, IFN-gamma, TNF-alpha showed a significant up regulation in the allograft that persisted through POD 14. mRNA for IL-2 was not significantly upregulated until POD 7 and persisted until POD 14. IL-2R was constitutively expressed in both isograft and allograft and was not a reliable predictor of rejection. Histologic rejection was moderately severe by POD 7 and severe between POD 8 and 14 correlating with the increasing expression of IL-6, IFN-gamma, and TNF-alpha. In summary, we have shown that increasing expression of mRNA for IL-6, IFN-gamma, and TNF-alpha not only correlated with severity of rejection but that upregulation began early when histologic evidence of rejection first occurred.

Animals↗
PubMed1994

Risk factors for liver transplantation across the ABO barrier.

A retrospective study was performed to identify risk factors affecting the fate of liver allografts transplanted across the ABO barrier. Over a 5-year period, 30 patients received 31 emergency OLTs with ABO-incompatible allografts. One-year graft and patient survival rates were 37.1% and 48.4%, respectively. This group was compared with 199 ABO-compatible OLTs performed under similar emergency conditions. Significantly higher incidence of rejection, hepatic artery thrombosis, and biliary stricture were found in ABO-incompatible grafts. The graft or patient survival of patients with O blood group or fulminant hepatic failure was not affected by ABO incompatibility. In contrast, the 1-year survival of recipients with non-O blood group was only 13.3% and the 1-year survival of those undergoing retransplantation was only 27.7% after ABO-incompatible OLT. A multivariate analysis using the Cox proportional hazard model identified non-O blood group (relative risk 3.43) and retransplantation (relative risk 2.46) as the most important risk factors for patient survival after ABO-incompatible OLT. We conclude that the use of ABO-incompatible grafts is justified in emergency cases when no other donor is available, but should be proscribed in patients with non-O blood group. The value of ABO-incompatible grafts in retransplantation is questionable and requires further investigation.

ABO Blood-Group System↗