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Biomedical subjects

S V Lynch

Publications and source records attributed to S V Lynch.

At least 55 records · Page 3Linked to original sources

Orthotopic liver transplantation for adult-onset type II citrullinaemia.

Citrullinaemia is a rare autosomal recessive disorder due to a deficiency of argininosuccinate synthetase (ASS). While the clinical course of the adult onset form (Type II) is unpredictable, many patients undergo sudden deterioration with progressive cerebral oedema. Two patients with Type II citrullinaemia were referred for liver transplantation. One patient was successfully transplanted, and his plasma citrulline level decreased from 300 to 69 mumol/l (normal range 20-60 mumol/l); Fisher's ratio increased to a normal range within 24 h of transplantation. The other patient died from cerebral oedema, despite Optimal pharmacological measures, while awaiting a suitable donor organ. Dietary and pharmacological treatment is vital before liver transplantation. The level of serum arginine requires regulation, as it can rise secondary to citrullinaemia in Type II disease. An immunocytochemical study of the liver in both patients showed a clustered distribution of ASS which is associated with a dismal prognosis compared with patients who have a homogenous distribution. Distribution of ASS was normal in the transplanted liver. Liver transplantation is effective therapy for adult-onset Type II citrullinaemia. A clustered pattern of ASS distribution in a liver biopsy is a significant feature to activate early referral for liver transplantation.

Adult↗

Resolution of cirrhosis-related pulmonary shunting in two children with a transplanted liver.

We treated two children with hypoxemia caused by intrapulmonary shunting associated with cirrhosis secondary to extrahepatic biliary atresia. Following orthotopic liver transplantation, digital clubbing and intrapulmonary shunting were resolved, as demonstrated by normalization of room air arterial blood gases, reduction in shunt fraction, and perfusion lung scanning with 99mTc-labeled macroaggregates of albumin. We recommend that early liver transplantation be considered for young subjects with a severe hepatopulmonary syndrome.

Biliary Atresia↗

The use of the lidocaine-monoethylglycinexylidide test in the liver transplant recipient.

The lidocaine-monoethylglycinexylidide (MEGX) test is used to monitor liver function in liver transplant recipients. Serial studies have been undertaken after 155 allografts. The initial MEGX concentration is significantly correlated with the donor MEGX concentration. It is also influenced by the recipient's pretransplant bilirubin concentration, being lowest among patients with very high bilirubin levels. Use of segmental grafts is also accompanied by low MEGX concentrations. The flow-dependent clearance of lidocaine makes it a sensitive indicator of disturbed liver blood flow, with decreased MEGX concentrations occurring in hepatic artery thrombosis and rejection and as a result of cardiac failure and pulmonary effusions. Significant hepatic ischemia resulting in delayed initial function or cholestasis also is associated with low MEGX concentrations. The initial median MEGX concentrations were lowest among patients who required retransplantation or who died within 2 months of allografting.

Adolescent↗

Sensitive, specific quantitative analysis of tacrolimus (FK506) in blood by liquid chromatography-electrospray tandem mass spectrometry.

The capacity of liquid chromatography-tandem mass spectrometry (LC-MS2) to detect and define individual components in a complex mixture has been utilized to develop a quantitative assay of the potent immunosuppressant drug, tacrolimus. Trough blood concentrations were measured in 175 samples obtained over several weeks after liver transplantation from seven patients. The assay was linear over the range of 0.2 to 100 micrograms/L. Imprecision was <8%, and accuracy was 99-101%. The turnaround time for a batch of 20 samples was 2.5 h. No interference from any of the other drugs being administered to the patients was evident. An ELISA also performed on the same samples overestimated the concentrations substantially, as indicated by a plot of the difference between the results for the two methods vs their mean. The favorable characteristics of the LC-MS2 assay, especially its sensitivity and specificity, will facilitate detailed pharmacokinetic studies of tacrolimus, particularly under circumstances in which metabolism is perturbed by either hepatic dysfunction or drug interactions.

Animals↗

Liver transplantation in the presence of situs inversus totalis: application of reduced-size graft.

Because of the anatomical features associated with situs inversus, technical difficulties will be encountered during orthotopic liver transplantation. This report describes the case of a patient with situs inversus totalis and end-stage liver disease from biliary atresia who was treated by segmental orthotopic liver transplantation. The segmental graft was safely placed in the left subphrenic space, and a suitable orientation was obtained for anastomoses of the hilar vessels. Chronic rejection necessitated retransplantation, by the same method, 19 months later. This technique has potential advantages in coping with anatomical obstacles encountered in patients with situs inversus.

Biliary Atresia↗

Renal glomerular lesions in unselected patients with cirrhosis undergoing orthotopic liver transplantation.

Renal biopsies were obtained from 23 patients at the time of orthotopic liver transplantation. Twelve biopsies showed minor glomerular abnormalities, 2 exhibited IgA nephropathy and one showed mesangiocapillary glomerulonephritis type I. The remaining 8 patients had glomerular lesions diagnosed as hepatic glomerulosclerosis (HGS). Immunofluorescence, available in 6 of the 8 biopsies with HGS, revealed granular deposits of immunoglobulins and complement in glomerular capillary walls and/or the mesangium. IgA was seen in 5 biopsies with HGS, but the staining for this protein was no more intense than that for the other immunoglobulins in 4 of these. Electron microscopy in HGS revealed partial mesangial interposition, hypertophy of mesangial and endothelial cells, granular material in a widened subendothelial space, slender projections of endothelial cytoplasm extending into the subendothelial space, and clusters of vesicles in the mesangium and glomerular capillary walls. These ultrastructural abnormalities have not hitherto been reported as a group of associated pathological changes. The renal biopsies were obtained from patients with advanced hepatic disease not selected because of urinary abnormalities or renal dysfunction. The frequency of lesions in this group of patients therefore probably reflects the true incidence of glomerular lesions in cirrhosis and related conditions. Progressive decline in renal function was not observed in any patient during follow up which ranged from 11 days to 55 mths.

Adolescent↗

A randomized trial of OKT3-based versus cyclosporine-based immunoprophylaxis after liver transplantation. Long-term results of a European and Australian multicenter study.

A multicenter randomized trial was performed to compare two immunosuppressive protocols after first ABO-compatible liver transplantation. Forty six patients were randomized to a 14-day treatment with Orthoclone (OKT3) in association with steroids and azathioprine, cyclosporine being progressively introduced on day 11 posttransplant. Fifty patients were randomized to a standard protocol of cyclosporine with steroids and azathioprine. Minimum follow-up was 1 year and graft and patient survivals were updated for the purpose of the study. The cumulative 1-year incidence of acute rejection tended to be greater in the cyclosporine group (75%) than in the OKT3 group (67%), especially when patients who did not receive full-course treatment with OKT3 were excluded (59%). Renal function was better preserved during the first two postoperative weeks in the OKT3 group than in the control group but plasma creatinine levels were comparable in both groups thereafter. The incidence of severe infections was lower in the OKT3 group (13.6%) than in the cyclosporine group (32%). The 4-year incidences of patient and graft survival in the OKT3 group (69% and 61%, respectively) were not different from those in the cyclosporine group (62% versus 54%, respectively). Thus this prospective trial shows that OKT3 immunoprophylaxis is a safe alternative to cyclosporine immunoprophylaxis in unselected recipients of a first liver graft.

Adolescent↗

The management and long-term results of Japanese pediatric liver transplant recipients.

We investigated the long-term results and ongoing management issues of 39 Japanese children who underwent liver transplantation in Brisbane, Australia. Whole liver grafts were used in 15 patients (Wh group) and reduced-size grafts were used in 24 patients (Re group). The 1-year and 3-year survival rates were 74% and 60%, respectively, and all cases of late mortality which occurred after 6 months were due to infection. Statistical analysis showed no differences between the Wh and Re groups with regard to late mortality or liver function tests, although 4 of 24 (16.7%) patients from the Re group developed a recurrence of esophageal varices. Three patients treated with cyclosporine developed lymphoproliferative disorders following transplantation, but none of the patients developed severe nephrotoxicity or hypertension. Although a "catch-up" gain in weight was observed, poor growth in height was displayed, and there were no differences between the Wh and Re groups in this regard. Thus, we conclude that late complications of liver transplantation in children are common and further studies are necessary to evaluate the ongoing growth problems.

Australia↗

Indwelling mesenteric venous catheterization for early detection of portal vein thrombosis: possible application to pediatric liver transplantation.

Portal vein thrombosis (PVT) is a well-recognized complication after liver transplantation, particularly in children. When it occurs early in the postoperative period, it has serious consequences, and rapid detection is essential. The purposes of this study were (1) to ascertain whether continuous monitoring of mesenteric venous pressure (MVP), via an indwelling mesenteric venous catheter, could assist in early detection of PVT and (2) to investigate the role of portography, via the catheter, in confirming this complication. An animal model of PVT was developed in pigs. At laparotomy, a heparin-coated catheter was inserted into a jejunal mesenteric vein, delivered percutaneously and connected to a pressure transducer. Conditions of PVT were simulated by progressive occlusion of the portal vein (PV) using a silastic tourniquet, and the degree of PV stenosis was assessed by Doppler ultrasound flow-velocity measurement. MVP was recorded 1 and 3 minutes after PV occlusion, and portography was performed via the indwelling catheter. There were significant increases in MVPs with all degrees of PV stenosis (P < .01, Student's t test). No significant changes in MVP were noted between 1 and 3 minutes postocclusion. Portography clearly demonstrated PV stenosis. There were no instances of PVT, despite repeated and prolonged occlusion of the PV. Progressive degrees of PV stenosis have been clearly detected by an indwelling mesenteric venous catheter in an animal model. This method may be useful for the diagnosis and treatment of PVT after pediatric liver transplantation.

Animals↗

Posttransplant gastrointestinal perforation in pediatric liver transplantation.

The results of 119 consecutive orthotopic liver transplants in 105 pediatric recipients were reviewed to determine the incidence and management of posttransplant gastrointestinal perforation (PTGIP). Transplantation of 22 children (21%) having had no previous surgery resulted in no PTGIP. However, 15 patients (14%) had PTGIP, and this group had had a greater number of previous laparotomies than did 68 children without PTGIP (2.3 +/- 0.9 v 1.5 +/- 0.8; P < .01). Up to 31% of children with two or more previous operations developed PTGIP. The incidence of PTGIP in patients with a preexisting stoma (26%, n = 23) was not significantly different from that in children whose previous portoenterostomy consisted of a simple Roux loop (15%, n = 60). A total of 32 laparotomies were performed for 35 PTGIP. The operative procedures included an oversewing of the perforated site (n = 22), segmental bowel resection/primary anastomosis (n = 5), creation of enterostomy (n = 7), and drainage (n = 1). After these laparotomies, reperforation occurred in 31% of patients, varying from none after defunctioning enterostomy for colonic perforations to 63% after simple oversew of perforated small bowel. Bolus methylprednisolone therapy or cytomegalovirus infection did not show any link with PTGIP. Children having undergone multiple laparotomies before liver transplantation are more susceptible to PTGIP. There was no death directly caused by PTGIP, but morbidity was considerable.

Humans↗

The safety of elective liver resection in a special unit.

The benefit of hepatic surgery for benign or malignant conditions is a balance between peri-operative morbidity/mortality and long-term potential for cure or palliation. The aim of this retrospective study was to illustrate that the safety of liver resection is a function of the frequently of performance of the procedure. Between 1973 and 1992, 327 elective liver resections were performed. The indication for surgery was malignant tumour in 275 cases of which 170 (62%) and 105 (38%) were for metastatic and primary disease, respectively, and non-malignant conditions in 52 cases. The series included the complete spectrum of hepatectomies. There were nine deaths (2.7%). Mortality was 8% (3/38) before 1985, 3.4% (3/89) between 1985-88 and 1.5% (3/200) between 1989-92. In non-jaundiced/non-cirrhotic patients, mortality was 1.4% (4/270). Morbidity, defined as the incidence of at least one major complication, occurred in 87 patients (26.6%) with a re-operation rate of 6.4%. During the same time periods, the morbidity rate was 42, 35 and 20%, respectively, and the median blood transfusion requirement and postoperative stay progressively decreased to 2 units and 9 days, respectively. In conclusion, as experience was gained, the need for blood transfusion diminished, morbidity and mortality improved and the hospital stay shortened.

Adolescent↗

Endotoxin levels in adult liver donors.

This study was undertaken to determine the levels of endotoxin in a group of adult donors whose livers were procured for transplantation. In the group of 25 adults, endotoxin levels were found to be significantly elevated in the systemic venous blood when compared to control levels. Portal venous endotoxin levels were also elevated following hepatic hilar dissection and after cannulation of the portal vein prior to removing the donor liver.

Adult↗