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Biomedical subjects

R Reding

Publications and source records attributed to R Reding.

At least 55 records · Page 3Linked to original sources

Prophylactic immunosuppression with anti-interleukin-2 receptor monoclonal antibody LO-Tact-1 versus OKT3 in liver allografting. A two-year follow-up study.

A prospective trial was conducted in 129 recipients of primary liver transplantation, to compare induction immunosuppression using triple drug therapy (cyclosporine, steroids, and azathioprine; group 1, n = 42), versus triple drug therapy with a 10-day course of OKT3 (group 2, n = 44) or of the anti-interleukin-2 receptor monoclonal antibody LO-Tact-1 (group 3, n = 43). Two-year actual patient survival rates were 64%, 79%, and 93% in groups 1, 2, and 3, respectively (1 vs. 2, NS; I vs. III, P = 0.003; 2 vs. 3, NS). Up to 2 years after transplantation, 18%, 44%, and 53% of the grafts in groups 1, 2, and 3, respectively, had not experienced steroid-resistant acute rejection (1 vs. 2, P = 0.002; 1 vs. 3, P = 0.007; 2 vs. 3, NS). The overall incidence of chronic rejection was 4%. OKT3 therapy, but not LO-Tact-1, significantly increased the incidence of cytomegalovirus infections (P = 0.019). In conclusion, immunoprophylaxis with LO-Tact-1 seemed to provide a liver graft acceptance rate at least as satisfactory as that with OKT3, without an increase in the incidence of infections.

Antibodies, Monoclonal↗

Microemulsion formulation of cyclosporine in pediatric liver transplantation.

The oral bioavailability of Sandimmun can be impaired by cholestasis, external biliary diversion, and diarrhea. We report two cases of pediatric liver transplant recipients who experienced chronic rejection and diarrhea secondary to proximal bowel resection. These conditions resulted in poor oral absorption of Sandimmun; the children were converted to the new oral microemulsion formulation Neoral, which significantly improved oral absorption, allowing intravenous cyclosporine weaning and patient discharge. Comparative pharmacokinetic studies were performed in both cases, and the relative Neoral/Sandimmun bioavailabilities were 32.9 and 5.4, respectively. Accordingly, Neoral may constitute to good alternative to ensure the effectiveness of oral cyclosporine administration, particularly in liver-transplanted children with severe cholestasis or shortened small bowel.

Administration, Oral↗

Primary calcification in post-transplantation lymphoproliferative disorder involving the hepatic graft: an exceptional finding.

Calcification within active post-transplantation lymphoproliferative disorders has, to our knowledge, never been described. We report the case of a 14-month-old boy who presented 4 months after orthotopic liver transplantation with a primary calcification in a lymphoproliferative nodule involving the hepatic graft. This calcification was detected by routine ultrasonography, visible on plain radiographs, and the post-transplantation lymphoproliferative disorder was histologically proved.

Calcinosis↗

Laparoscopic splenectomy in adults and children: experience with 31 patients.

BACKGROUND: Open surgery is the standard approach for splenectomy in hematologic disorders, but a few cases of successful laparoscopic splenectomy have been reported. METHODS: Thirty-one patients (18 adults, group 1; and 13 children, group 2) underwent laparoscopic splenectomy. Indications for surgery included idiopathic thrombocytopenic purpura (25 patients), congenital spherocytosis (4 patients), and hemolytic anemia (2 patients). In 97% of the patients the diameter of the spleen was less than 15 cm. RESULTS: Laparoscopic splenectomy was successful in 94% of the patients; conversion to open surgery was mainly related to hemorrhage. Accessory spleen was found in 39% in group 1 and 8% in group 2. Two adults received intraoperative autotransfusion. Postoperative morbidity was minimal. The median postoperative stay was 3 days (range, 2 to 12 days) in group 1 and 2 days (range, 2 to 5 days) in group 2. CONCLUSIONS: Laparoscopic splenectomy is safe in both adults and children. Adequate selection of patients (small-size spleen, splenic destruction on preoperative scanning of platelets), appropriate preparation in patients with idiopathic thrombocytopenic purpura (immunoglobulin G), and meticulous surgical technique (with routine opening of the gastrocolic ligament to search for accessory spleen) are key factors in obtaining the same long-term results as with open surgery.

Adolescent↗

Orthotopic liver transplantation for Crigler-Najjar type I disease in six children.

Hyperbilirubinemia in Crigler-Najjar disease type I (CN) can be partially controlled by daily phototherapy, but these children remain at permanent risk of developing brain damage due to kernicterus. Because liver transplantation is the only available curative treatment for liver-based inborn errors of metabolism, orthotopic liver transplantation (OLT) was performed in six patients with CN. Mean age at surgery was 52.5 months (range 27 to 100). Despite a mean daily phototherapy of 12.4 +/- 0.8 hr, mean bilirubin of the 6 patients was 388 microM/L (range 175 to 703) before OLT; one of them was also being treated with tin-protoporphyrin. All 6 had elevated AST/ALT, ranging from 1.4 to 6 times upper normal values. Complications occurred in three patients after OLT, including miliary tuberculosis in one, graft rejection and retransplantation in one, and hepatic artery thrombosis in one. All patients survive with normal serum bilirubin level (follow up 6 to 116 months). Four have normal enzymes on post-OLT follow-up (30 to 95 months), follow a normal education program, and have a normal social life. One recently transplanted patient has progressively normalizing liver function tests 6 months after OLT. One patient transplanted at 8 y.o. (now 116 months post-OLT) has moderate neurological delay due to pretransplant kernicterus, and posttransplant chronic persistent hepatitis. Our series shows that OLT cures hyperbilirubinemia in CN patients, with an excellent survival prospect. The procedure should be decided upon before neurological sequelae occur, since these persist after transplantation.

Adolescent↗

Standardized quick en bloc technique for procurement of cadaveric liver grafts for pediatric liver transplantation.

This paper describes a quick procedure for cadaveric liver graft retrieval during multiple organ harvesting. The technique is based on minimal preliminary dissection, absence of in situ direct portal perfusion, and en bloc removal of the liver and pancreas, with an aortic patch encompassing the coeliac trunk and superior mesenteric artery. The results of 110 pediatric liver transplantations with 109 organs harvested using this technique are reported. There were no graft harvesting injuries. The liver graft primary nonfunction rate was 4.5% (5/110). The 3-month retransplantation rate was 10%. The actual patient survival rates were 93% at 3 months and 90% at 1 year; actual graft survival rates were 85.5% and 78%, respectively. The technique described was at least as safe as conventional procedures. A major advantage of the procedure is its flexibility, which allows for the easily combined procurement of other organs (whole pancreas and intestine).

Adolescent↗

Role of hepatitis C virus in chronic liver disease occurring after orthotopic liver transplantation.

Paediatric orthotopic liver transplant recipients may develop chronic hepatitis after surgery. To investigate the role of hepatitis C virus in this pathology a cohort of 249 paediatric orthotopic liver transplant recipients was studied. Sixteen children (6.4%) were found to have chronic hepatitis C virus hepatitis after orthotopic liver transplantation. All but one of them had serum transaminase values which were persistently raised two to eight times the upper limit of normal. Thirteen were positive for both serology and serum hepatitis C virus RNA. Serum hepatitis C virus RNA detection occurred five to 33 months before hepatitis C virus antibodies. Liver tissue hepatitis C virus RNA and hepatitis C virus core antigen were detected in five. In one patient, tissue hepatitis C virus core antigen was detected when other tests for hepatitis C were negative. Two patients had positive human cytomegalovirus serum antibodies and RNA before transplantation. Although serum hepatitis C virus RNA was not detected after transplantation, serum enzyme immunosorbent assay and tissue core antigen were still detectable in both patients. In another child, serum hepatitis C virus RNA was positive and hepatitis C virus core antigen was found on a liver biopsy specimen but antihepatitis C virus antibodies were negative as well as liver hepatitis C virus RNA. No patient developed severe liver disease or cirrhosis during a follow up of up to 72 months. It is concluded that hepatitis C virus is a significant cause of morbidity after paediatric orthotopic liver transplantation. Diagnosis cannot rely on serological testing only. The patients remained stable on follow up, but longer prospective histological studies remain necessary to establish prognosis.

Antigens, Viral↗

HPLC-microparticle enzyme immunoassay specific for tacrolimus in whole blood of hepatic and renal transplant patients.

Tacrolimus is a relatively new immunosuppressant used in organ transplantation to prevent graft rejection. However, its use is not devoid of side effects, making it important to maintain blood concentrations within therapeutic ranges. Several analytical methods are currently available for routine drug monitoring. However, these methods are based on use of the same monoclonal antibody, which also cross-reacts with some metabolites, resulting in overestimation of some blood concentrations. Even though this antibody appears appropriate for therapeutic drug monitoring, no reference method measures only the parent drug, mainly because of the poor absorptivity of tacrolimus in ultraviolet light. We have developed a method displaying an increased specificity towards the unchanged drug, using conventional equipment available in most clinical laboratories. After chromatographic separation of the blood extract, the tacrolimus fraction is analyzed by an automated microparticle enzyme immunoassay (MEIA) performed on the IMx analyzer (Abbott Labs.). This method is linear from 0 to 40 micrograms/L, yields CVs from 8.5% to 18.2%, and has a detection limit of 5 micrograms/L. Tacrolimus concentrations obtained by HPLC-MEIA in hepatic and renal transplant patients are from 47.5% to 18.8% lower than those obtained by MEIA, according to liver function tests and metabolite accumulation, even though no significant differences were observed between the methods for drug-free blood samples supplemented with known amounts of tacrolimus.

Antibodies, Monoclonal↗

Mitochondrial respiratory chain defect: a new etiology for neonatal cholestasis and early liver insufficiency.

Two siblings presented with neonatal cholestasis and early liver insufficiency. The older was admitted for end-stage cirrhosis with severe hypoglycemia and had long-term successful liver transplant at the age of 15 months. The second child presented a similar neonatal history of cholestasis, hypoglycemia, hyperlactacidemia, liver insufficiency and progressive cirrhosis. Extensive work-up excluded all known causes of neonatal cholestasis. Gluconeogenesis was found normal following alanine and fructose infusion. Repeated hypoglycemia with early post-prandial hyperlactacidemia led us to investigate the mitochondrial respiratory chain enzyme activities. Selective defects of complexes I, III and IV, coded by mitochondrial DNA, were detected in liver tissue of this patient and on preserved frozen tissue from his sibling, whilst normal activities were found in liver tissue samples from control patients with end-stage liver diseases. No extrahepatic manifestations were found. We conclude that liver deficiency of mitochondrial respiratory chain enzymes may cause liver disease in neonates, associated with hypoglycemia and post-prandial hyperlactacidemia. The disease is cured by liver transplantation.

Acidosis, Lactic↗

Liver procurement without in situ portal perfusion. A safe procedure for more flexible multiple organ harvesting.

The outcome after liver transplantation when grafts were retrieved from the donor by the classical aortic and portal cooling (APC) method was compared with the outcome when exclusively aortic in situ perfusion (AC) was used. Retrospectively, 163 donor hepatectomies performed over a 20-month period were reviewed to analyze overall graft (APC n = 78, AC n = 85) and patient outcome. The global graft and patient survival rates were not significantly lower in the APC group, except for 3-month graft survival (APC 72%, AC 87%; P = 0.015). However, this could be unrelated to the technique. In a subgroup of 140 cases (APC n = 64, AC n = 76), a more detailed analysis was performed. Populations of donors and recipients were similar. The graft injury and the immediate graft function were not significantly different between both groups. A multivariate analysis shows that low donor weight (P = 0.007), donor hypernatremia (P = 0.014), and in situ portal perfusion (P = 0.045) were significant determinants of a higher postoperative peak of glutamic pyruvic transaminase. In summary, in this series, routine human liver procurement using exclusive aortic perfusion seemed to be at least as safe as using a combined aortic and portal perfusion technique. This simplified method may also represent some advantages for combined pancreas and intestinal harvesting in the future.

Adenosine↗

In vivo IgM depletion by anti-mu monoclonal antibody therapy. The role of IgM in hyperacute vascular rejection of discordant xenografts.

Xenoreactive natural antibodies (XNA) and complement activation are thought to be the 2 main factors responsible for the hyperacute vascular rejection (HVR) of discordant xenografts. The aim of this work was to study the role of IgM XNA in the HVR of guinea pig to rat cardiac xenografts, a discordant model. Adult LOU/C rats were depleted of circulating IgM and therefore of IgM XNA using an anti-mu mAb (mouse anti-rat IgM mAb 7 [MARM-7]). Rats were injected with 10 mg and 5 mg of MARM-7 at days -3 and -1, respectively, and guinea pig cardiac xenografts were performed on day 0. Control animals were injected on the same days with 10 mg and 5 mg of anti-alpha mAb (MARA-1) or equivalent volumes of PBS. Xenografts were performed on day 0. Guinea pig cardiac xenograft survival time was significantly prolonged in IgM-depleted animals (62 min, P < 0.01) compared with controls using PBS (18 min) or MARA-1 mAb (12 min). This prolongation was not due to a decrease in the complement activity in IgM-depleted rats, since no significant variation of the C1q, C4, C3, and C5 complement hemolytic activity was observed between control and treated animals before HVR. Prolongation of the xenograft survival time in the MARM-7-treated group was correlated with an undetectable serum level of IgM and IgM XNA and a lack of IgM XNA deposits on the rejected xenograft vascular endothelium. Contrarily, both IgM-depleted and control animals showed C3 deposits on the rejected xenograft vascular endothelium and myocardium, as well as diffuse deposits of IgG2a XNA. Although HVR was not abrogated by the depletion of IgM XNA, our data indicate that IgM is implicated in the HVR and that the anti-mu approach is a potential therapeutic treatment for discordant xenografts. Finally, we suggest that other factors such as IgM-independent activation of complement might be one of the mechanisms responsible for the pathogenesis of HVR in the guinea pig to rat xenograft model.

Animals↗

Technical problems in shipped hepatic allografts: the UCL experience.

Due to developments in surgical techniques and organ preservation, the shipping of renal and extrarenal organs is becoming increasingly more frequent. During the period from 1 January 1991 to 31 December 1992, 39 of 180 (21%) implanted liver allografts were shipped to our center by local harvesting teams. The fact that each of nine livers (23.1%) presented with minor and major (vascular and parenchymatous) problems stresses the need for better surgical training and standardization in procurement techniques. The introduction of a liver allograft feedback report could be an easy way to perform quality control.

Belgium↗