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Biomedical subjects

P McMaster

Publications and source records attributed to P McMaster.

At least 109 records · Page 6Linked to original sources
PubMed1996

Liver transplantation in Birmingham: indications, results, and changes.

The improvements in survival following liver grafting during the last five years reflect refinements in technique and in immunosuppressive regimens. Cirrhosis due to Hepatitis C and alcohol have become more common indications in this center. Efforts are being made to overcome the problems of donor organ shortage by using 'marginal' donors and by splitting liver grafts.

Adult↗
PubMed1995

Timing, significance, and prognosis of late acute liver allograft rejection.

Liver allograft rejection is usually divided into acute (cellular) rejection and chronic (ductopenic) rejection. Most cases of acute rejection occur within four weeks of transplantation. There is a paucity of published literature on late acute rejection (LAR) in liver allografts and little is known about factors affecting its occurrence and outcome. To study the predisposing factors, clinical presentation, and prognosis of LAR, data prospectively collected on consecutive adult patients who underwent liver transplantation between 1982 and 1994, were analyzed. LAR was defined as histologically confirmed acute cellular rejection occurring 30 or more days after liver transplantation. Of the 717 patients, 59 (7.5%) had 71 episodes of LAR. Fifty-seven episodes were seen during the first year after transplantation, the remaining occurring between 1 and 6 years. Age, sex, pretransplant diagnosis, donor match of HLA, and blood groups was not associated with risk of LAR. Twenty-seven (38%) episodes were preceded by subtherapeutic blood levels of cyclosporine/FK506 (< 100 ng/ml and < 5 ng/ml, respectively) while an additional 6 (8%) had marginally low blood levels (< 150 ng/ml and < 10 ng/ml, respectively). Treatment with high-dose prednisolone resulted in complete resolution of rejection in 36 (51%) episodes, partial response in 21, and no response in 14 patients. Sixteen patients (27%) developed chronic rejection and graft loss. Development of chronic rejection was not affected by age or sex of the patient, timing of LAR, or histological severity of AR. Delayed response to therapy during an earlier episode of AR, and histological findings of centrilobular necrosis or bile duct loss at the time of diagnosis of LAR were associated with high risk of progression to chronic rejection and graft loss.

Adolescent↗
PubMed1995

Sex mismatch as a risk factor for chronic rejection of liver allografts.

Chronic irreversible rejection is a major cause of graft loss and retransplantation after orthotopic liver allotransplantation. To identify risk factors we retrospectively analysed 423 adult consecutive primary liver allograft recipients. The endpoint of the study was graft failure due to chronic rejection leading either to retransplantation or death. Chronic rejection developed in 22 (5.2%) patients. Pretransplant diagnosis of primary biliary cirrhosis or autoimmune hepatitis, recipient age less than 30 years, 1 or more episodes of acute cellular rejection, and transplantation of an organ from cytomegalovirus (CMV). IgG positive donor to an IgG negative recipient were identified as risk factors for chronic rejection. Transplantation of a liver from a male donor into a female recipient was also associated with an increased probability of chronic rejection. By logistic regression analysis, the probability of chronic rejection was predicted by: sex and cytomegalovirus match of donor and recipient, the presence of acute rejection, recipient age, transplantation for autoimmune hepatitis or primary biliary cirrhosis, and recipients receiving no azathioprine during the third month after transplantation. Sensitisation to antigens expressed by bile-duct epithelium as in primary biliary cirrhosis or exposure to donor bile-duct minor histocompatibility antigens, such as the male sex related H-Y antigen, may provide an explanation. More selective allocation of donor organs may allow a reduction in the incidence of ductopaenic rejection and graft loss.

ABO Blood-Group System↗
PubMed1995

Enisoprost in liver transplantation.

Previous human studies in renal transplant recipients have shown a lower incidence of acute rejection and cyclosporine-associated acute nephrotoxicity when prostaglandins are administered in conjunction with standard immunosuppressants. This study evaluates the effects of enisoprost (EP), a synthetic PGE methyl ester analog, in a single-center, prospective, randomized, double-blind, placebo-controlled, parallel group trial in 81 consecutive adult patients undergoing orthotopic liver transplantation (OLT). The subjects received EP 100 mg p.o. t.i.d. (n = 40) or placebo (n = 41) for the first 12 weeks after OLT. Immunosuppression was based on cyclosporine, azathioprine, and corticosteroids. Effective renal plasma flow and glomerular filtration rate were determined at 4 and 12 weeks after OLT. Eighty-one patients entered the study; sixty-six patients completed the 16-week study period. There were no statistically significant differences between EP- and placebo-treated groups at 12 weeks for creatinine clearance, glomerular filtration rate, and effective renal plasma flow. At least 1 episode of cyclosporine nephrotoxicity occurred in 7/40 patients (17.5%) in the EP group compared with 9/41 patients (20.0%) in the placebo group (P = 0.781). There was no significant difference in the incidence of graft rejection episodes in the 2 groups. Enisoprost, as used in this study, does not have any beneficial effect on renal function or incidence of rejection in OLT recipients.

Adult↗
PubMed1995

Inflammatory bowel disease in primary sclerosing cholangitis: an analysis of patients undergoing liver transplantation.

Fifty-five patients undergoing orthotopic liver transplantation (OLT) for primary sclerosing cholangitis (PSC) were reviewed retrospectively. After OLT there were significantly more episodes of acute rejection in 31 patients with a previous history of inflammatory bowel disease (IBD) than in 24 without such a history. Patients who had severe acute rejection were significantly younger at diagnosis of IBD. Five patients with histological features suggestive of recurrent PSC after OLT were significantly younger at the time of transplantation than those who did not develop recurrence. Patients with poor control of IBD after OLT had a significantly lower age at diagnosis of bowel inflammation. The presence of IBD did not affect the outcome after OLT, but was associated with a higher rate of acute rejection. Younger patients had a greater risk of developing severe rejection, recurrent PSC and poor control of IBD after liver transplantation.

Adolescent↗
PubMed1995

Quantitation of cytomegalovirus in the blood of liver transplant recipients.

An assay for quantitation of cytomegalovirus (CMV) has been developed. The assay combines DNA amplification and enzyme-linked immunosorbent assay (ELISA) detection. In this study, the assay has been used to examine sequential buffy-coats from 32 consecutive liver transplant recipients. In a febrile patient, CMV titres in excess of 10(4) copies per 150,000 cells strongly suggest a diagnosis of symptomatic CMV infection. Antiviral therapy causes a rapid decline in viral titre. Viral titres are seen to rise presymptomatically in some patients. Median peak viral titres differ significantly between symptomatic patients (1.1 x 10(5)), asymptomatic CMV IgM-positive patients (1.7 x 10(3)), and asymptomatic CMV immunoglobulin (Ig)M-negative patients (2.9 x 10(2)). CMV quantitation can be used for diagnosis and surveillance and can also be used to monitor antiviral treatment.

Adult↗
PubMed1995

Biliary complications after paediatric liver transplantation: Birmingham's experience.

Between 1983 and 1992, 112 children underwent liver transplantation. Of 138 grafts, 60 (43.4%) were whole livers, 77 (55.6%) were reduced livers, and 1 (0.7%) was a split liver. Biliary complications (BC) were defined as any abnormality, even minor, related to the biliary tract. Results were analysed with a minimum follow-up of 9 months. Some 36 grafts (26.1%) in 34 patients (30.4%) presented with BC: bile leaks (17 grafts), biliary obstructions or dilatations (16 grafts), and other complications (3 grafts). Management was mainly surgical with biliary reconstruction via a Roux-en-Y loop. Interventional radiology had an increasing role in recent years. BC were associated with a mortality of 1.8% (2/112), a graft loss rate of 4.3% (6/138), and significant morbidity. Among the various factors whose association with BC was studied, the date of transplantation, the use of reduced grafts and the use of gallbladder conduits appeared to be the main determining factors for BC. From multivariate analysis the use of reduced grafts emerged as the most important factor in reducing BC. We therefore conclude that BC are associated with significant morbidity, but general improvements in both surgical and medical management seem to account for better results in recent years.

Adolescent↗
PubMed1995

Rat heart-aorta cluster transplantation: a novel model to study transplant rejection.

The purpose of this study was to develop a microsurgical cluster model of heart plus entire thoracic aorta transplantation and to compare it to the isolated model of heart transplantation as a tool to study transplant rejection. Thirty-six syngeneic (DA x DA and Lew x Lew) and allogeneic (DA x PVG and DA x Lew) cluster heart-aorta transplants were compared to 43 syngeneic and allogeneic isolated heart grafts. Graft survival, recipient survival and histological data on myocardial and aortic tissues were assessed. There was no statistically significant difference in graft survival between the two models studied (P > 0.05). In the cluster transplants, the aortic component was spared the severity of acute rejection noted for the myocardial counterpart. In conclusion, the results demonstrated that the cluster model was technically feasible and highly reproducible. Additionally, it was possible to apply this model to the study of experimental allograft rejection using novel immunosuppressants. The success of the cluster model in strongly mismatched transplant strain combinations underscores its potential for application in slower rejection combinations, making it particularly suited for chronic rejection studies. The inherent capacity for sampling a broader range of vessel sizes in one animal makes the cluster model more suitable than the isolated models of aorta or heart for application to experimental protocols.

Animals↗
PubMed1995

Therapeutic drug monitoring of tacrolimus in clinical transplantation.

Initial clinical trials of FK did not incorporate available FK levels, and difficulties were quickly experienced particularly with neurotoxicity and nephrotoxicity. The introduction of routine assay allowed broad parameters to be identified, which assisted in evaluating effective therapeutic parameters. Levels approximately 20 ng/ml were frequently associated with toxicity and the initial therapeutic range between 10-25 ng/ml was probably excessive. Reliable effective assay > 5 ng/ml using the Abbott IMx is not available, and many patients will have excellent hepatic or renal function with what are currently undetectable levels of FK. However, IncStar have an ELISA assay with a sensitivity of 0.5 mg/ml. Clinical practice does not, at this time, dictate elevation of FK, although careful monitoring continues. Education of oral administration from 0.15 mg/kg to 0.1 mg/kg in combination therapy with steroids and 0.05 mg/kg with azathioprine and steroids has led to revision of therapeutic parameters, e.g., 5-15 ng/ml is now widely used. Therapeutic drug monitoring is important to avoid unnecessary toxicity, but the lower limit has not been fully defined. Clearly, many patients with < 5 ng/ml have excellent hepatic function.

Drug Monitoring↗
PubMed1995

Failure to incriminate hepatitis B, hepatitis C, and hepatitis E viruses in the aetiology of fulminant non-A non-B hepatitis.

Sporadic non-A, non-B hepatitis is the most common indication for liver transplantation in patients presenting with fulminant and subacute liver failure. This study used serological, histological, and molecular biological techniques to examine specimens from 23 consecutive patients transplanted for sporadic non-A, non-B hepatitis. No evidence was found of hepatitis C virus, hepatitis E virus, or 'cryptic' hepatitis B virus infection.

Adolescent↗
PubMed1995

Restorative proctocolectomy and pouch anal anastomosis for ulcerative colitis following orthotopic liver transplantation.

This study reports on the outcome of four patients having ileal pouch anal anastomosis after orthotopic liver transplantation for sclerosing cholangitis complicating ulcerative colitis. There were no deaths on follow up. Early postoperative bleeding was a complication of colectomy or rectal excision in three, one of whom developed hepatic artery thrombosis and the overall complication rate was high. All patients are continent but one has chronic pouchitis (while receiving longterm metronidazole) and one patient has recurrent sclerosing cholangitis in the transplant.

Adult↗
PubMed1994

Policies in Europe on "marginal quality" donor livers.

Shortage of donor livers has led several liver transplant centres to widen their definition of liver donor suitability. We have assessed the function of liver grafts from "marginal" donors and attitudes to use of such organs. Over an 18-month period, livers used in 30 of 213 consecutive liver transplantations in Birmingham, UK, came from marginal donors (history of alcoholism, abnormal liver function test results, drug overdose that included paracetamol, advanced cardiovascular disease, sepsis, lengthy hypotension [systolic blood pressure < 80 mm Hg for > 1 h], high-dose inotropic drug use). 16 of these donors had been refused by other UK liver transplant centres, 11 on medical grounds. The controls were grafts retrieved from "good" donors (n = 183) during the same period. All 30 grafts showed satisfactory early function but had greater day 1 (p = 0.004) and peak serum aspartate aminotransferase (p = 0.0008) values than control grafts. Graft and patient survival at 1 year in the two groups was similar (72% vs 73% and 80% vs 82%, respectively). To assess attitudes to marginal donor livers, a questionnaire outlining the details of these 30 donors was sent to the 80 centres in the European Liver Transplant Group, and 60 replied. Median immediate refusal rate of the marginal donors was 7/30 (range 0-18) and median outright acceptance rate was only 11/30 (1-26). Larger centres were less selective, with a significantly lower refusal rate (p = 0.03). These results indicate that, because of existing liver donor criteria within Europe, usable donor livers are being unnecessarily refused on medical grounds.

Adolescent↗