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Liver support systems (LSS) incorporating living xenogeneic (porcine) cells are currently in clinical use. However, their efficacy remains uncertain, and there are concerns regarding possible disease transmission. A key component of LSS is a semipermeable membrane (SPM) that separates the patient's circulation from the xenogeneic cells, and it is the pore sizes of the SPM that determine the size of molecules passing between the patient's circulation and the foreign cells. To achieve effective detoxification of the blood of patients with liver failure, it is probable that pore sizes must be of a size that could allow passage of viruses potentially infective to humans. We review the current state of clinical exogeneic LSS and discuss the major issues surrounding their use. With approximately 40 patients treated over the past 9 years, we conclude that LSS presently in use produce effective short-term benefits with no reports of immunological, physiological, or pathological complications. Nevertheless, with the pore sizes of SPM in use, disease transmission seems possible, and further advances are required. Our results support the establishment of the controlled clinical trials presently underway.

Background. Liver allografts in spontaneously tolerant strain combinations can protect other organs of the same donor origin from rejection and reverse ongoing rejection in previously placed grafts. The aims of this study were to examine whether liver allografts have the same protective effect on islet allografts and to investigate the underlying mechanisms. Methods. PVG islets were transplanted beneath the kidney capsule of streptozotocin-induced diabetic DA rats with or without liver allografting. The cellular infiltrate, and the extent of apoptosis and of Fas ligand (FasL) expression in the islet grafts were evaluated on days 2, 4, and 7 after transplantation by means of immunostaining and the in situ terminal deoxynucleotide transferase-mediated dUTP nick end labeling assay. Donor and recipient mixed lymphocyte reactions (MLR) were determined at 7 days or 100 days after islet transplantation. Results. Islet allografts transplanted alone were rapidly rejected within 5-8 days. Rejection was delayed, but not prevented, when islets were transplanted simultaneously with the liver. Liver transplantation 1 month before islet transplantation resulted in long-term survival (>100 days) of islet grafts in three of seven animals, whereas the other four died of liver rejection with functional islet grafts. Liver transplantation on day 4 after islet grafting reversed ongoing islet rejection and led to indefinite islet graft survival in three of seven cases. There was a progressive increase of cellular infiltration in all of the islet allografts, but the intensity of the infiltrate did not correlate with the outcome of the islet allografts. Islet rejection was characterized by an early dominance of monocytes/macrophages and CD25+ T cells in the infiltrates, a high incidence of apoptotic β cells in grafts, and a sensitized status in the MLR. Tolerance of islet allografts was associated with increased numbers of dendritic cells in the graft infiltrates, up-regulation of FasL, and prominent apoptosis of alloreactive leukocytes in the islet grafts, as well as donor-specific MLR suppression in long-term survivors. Conclusions. These results demonstrate that the extent of the protective effect of liver transplantation on islet allografts varies with the time of liver grafting, ranging from delay in islet rejection to complete islet acceptance. Islet graft tolerance induced by liver transplantation is the result of an immune process that involves up-regulation of Fas ligand expres-sion on, and apoptosis of, islet graft infiltrating lymphocytes.

Orthotopic partial liver transplantation (PLT) models were developed in rats to explore the unique role of the liver in transplant tolerance. In PVG rats, syngeneic PLT established that surgical reduction to one-third of the liver and orthotopic transplantation permitted survival. Allogeneic PLT in the PVG to DA liver-tolerant model, both 50% and 33%, did not affect the tolerogeneic property of the liver, with all PLT recipients surviving indefinitely. Blood samples taken at various time points for detection of donor cells using flow cytometry showed a steady increase in donor cell chimerism in both PLT and whole liver transplantation (WLT) recipients that persisted throughout the 3-month observation period. At each time point, the level of donor cell chimerism in PLT was higher than that in WLT. We conclude that transplantation of one-third of the liver is compatible with survival in rats. Reduction of antigenic load by means of hepatectomy does not affect the tolerogenic effect of the liver in the PVG to DA LT model because of the remarkable regeneration capability of the liver. Peripheral chimeric levels increase progressively after WLT, suggesting that this is an ongoing immunological phenomenon. The earlier and increased chimerism after PLT may be associated with liver regeneration. © 2001 Wiley-Liss, Inc. MICROSURGERY 21:183–187 2001

Background: A practical liver support system for patients in fulminant hepatic failure (FHF) remains a needed therapeutic modality. A new method of bioartificial liver support, the liver biodialysis system (LBDS), is described. Methods: Porcine hepatocytes, removed from direct contact with the treated subject’s circulation, are in culture in a bioreactor which is combined in a dialysis circuit for patient treatment. The LBDS was tested in a porcine ischaemic hepatic failure model. Results: The viable hepatocyte content of the bioreactor was 2.49 ± 0.72 × 10 10. Cells remained viable in culture throughout the experiments (30 ± 3 h) without evidence of immunological damage. A decrease in the degree of accumulation in the blood of ammonia (P < 0.02) and of 14 amino acids (P < 0.001) was achieved by the LBDS. Cerebral perfusion pressure was maintained at significantly higher levels in LBDS-treated animals (P < 0.05). Conclusions: In the LBDS, hepatocytes in large numbers and satisfactory culture conditions in a bioreactor have sustained viability and function. When combined in a dialysis circuit for the treatment of FHF pigs, immune reactions between the blood and hepatocytes were prevented and beneficial metabolic effects were observed.

Hepatocytes encapsulated in alginate-poly-1-lysine-alginate (APA) are used in transplantation studies and in bioartificial liver support systems. Loss of cell viability in the process of APA encapsulation is usually 20–30% while the effect on cytochrome CYP450 activity is rarely reported. This work investigates the negative influences on hepatocyte viability and CYPIA1 activity during APA encapsulation, and reports methods to alleviate these influences by incorporating certain reagents into the encapsulation solution. The results show that loss of hepatocyte viability and CYPIA1 activity was caused almost entirely by extracellular calcium toxicity rather than by mechanical damage (p 0.05) or result in satisfactory microcapsules. Hepatocyte viability was 25% higher (p < 0.05) in CaCl2 than in calcium lactate (CaLa) when the cells wer...

In the PVG (RT1(c)) to DA(RT1(a)) rat combination, liver allografts are spontaneously accepted across a complete MHC barrier while cardiac and renal allografts are rejected. We postulated that this spontaneous liver acceptance was associated with the large quantity of antigen in the transplanted liver. In order to test this hypothesis, we have developed three different models of multiorgan transplantation: model I, triple heart transplantation; model II, triple kidney transplantation; and model III, double heart and double kidney transplantation. The results showed that prolongation of heart and kidney allografts was achieved with the increasing number of organs transplanted. The models proved reliable and useful in transplant immunological studies.

The aim of this work was to develop a vascularized skin transplantation model in the rat to allow comparison of the immunological events with those of classic free skin grafts and vascularized organ grafts. Seventy-nine syngeneic transplants were performed using inbred Wistar and PVG rats to develop the model. Epigastric skin flaps were taken with a vascular pedicle of common femoral artery and vein and implanted on the back of the neck. The graft vessels were anastomosed end-to-end and end-to-side to the recipient common carotid artery and external jugular vein with interrupted 10-0 nylon sutures under an operating microscope. A high success rate (11 of 11) was achieved in the final method developed, with light microscopy confirming normal skin structure in the flaps following transplantation. The advantages of the model include comparable skin size to that commonly used for nonvascularized skin grafts, while the physiology in terms of blood supply is similar to that of vascularized organ grafts; the grafts are visible with free access for biopsy; and the size of the graft can easily be varied to allow studies concerning antigen load.

The new 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) colorimetric assays for assessing hepatocyte density, viability and proliferation were evaluated and compared with 3-(4,5-dimethlthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and tritiated thymidine (3HTdR) incorporation. OD values of MTS or XTT, which are metabolically reduced in viable cells to a watersoluble formazan product and can be read directly, had a good correlation coefficient with hepatocyte densities in a range of 2.5–40×104 cells/ml (MTSr=0.952; XTTr=0.902) and with hepatocyte viability (MTSr=0.974; XTTr=0.975). At 0, 20, 40 and 60 hr cultures, the correlation coefficients with3HTdR for assessing hepatocyte viability and proliferation (MTSr=0.942–0.981; XTTr=0.953–0.992) were excellent. In contrast with MTS and XTT, MTT OD values had a poor correlation coefficient with hepatocyte densities (r=0.672), viability (r=0.622) and3HTdR incorporation (r=0.701–0.818 at 0, 20 and 40 hour cultures). This study shows that the MTS or XTT colorimetric assays for assessing hepatocyte density, viability and proliferation are more accurate, reliable and simpler than the widely used MTT assay. They avoid use of radioactive material as required for3HTdR incorporation. Of the two, the MTS colorimetric assay is more sensitive than the XTT.

Background Hepatic resection with total vascular isolation has been reported to reduce hemorrhage. Addition of supraceliac aortic clamping putatively avoids hemodynamic instability, bdbut may increase morbidity. Methods This technique was used in 99 major liver resections utilizing scalpel division and suture hemostasis. Results Livers were normal in 86 patients, cirrhotic with no portal hypertension in 5, and cirrhotic with portal hypertension in 8. There was 1 death in 91 patients with no portal hypertension compared with 5 in 8 patients with portal hypertension due to hepatic failure or bleeding esophageal varices. There were 59 hemihepatectomies and 40 segmentectomies. Median operating time was 145 and 110 minutes, respectively, and mean transfused blood was 4 and 0 units, respectively, with minimal morbidity. Conclusions Use of total hepatic vascular isolation with routine supraceliac aortic clamping is a safe and expedient method of hepatic resection that limits blood loss and maintains hemodynamic stability, but does not increase morbidity. However, the presence of portal hypertension precludes safe resection.

We studied 35 adult patients (mean age = 43 yr) referred for orthotopic liver transplantation. Spinal bone mineral density was measured by quantitative computed tomography scanning before transplantation (n = 35) and at 3 mo (n = 21) and 12 mo (n = 11) after orthotopic liver transplantation. The readings were corrected to age 50 yr, using the regression equations derived from normal control subjects. Quantitative bone histological studies were performed in 17 patients before orthotopic liver transplantation and 3 mo after orthotopic liver transplantation. Before orthotopic liver transplantation, the corrected spinal bone mineral density in men was 108 ± 20 mg/cm3, less than in male control subjects (129 ± 22 mg/cm3, p < 0.005). In women patients the value was 117 ± 27 mg/cm3, and in female control subjects 126 ± 19 mg/cm3 (NS). However, women patients with primary biliary cirrhosis had lower spinal bone mineral density (106.5 ± 14.8) than female control subjects (p < 0.005). Histologically, the resorbing surface was near the normal mean, whereas the osteoblast surface, tetracycline surface and bone formation rate was lower in men (p < 0.05) but not women. Spinal bone mineral density decreased by 24% in the first 3 mo after orthotopic liver transplantation with no further decrease at 12 mo. Five patients had vertebral fractures within 6 mo of orthotopic liver transplantation. One patient fractured a wrist and three had osteonecrosis of the hip or knee. Bone histological studies 3 mo after orthotopic liver transplantation showed no change in resorbing surface but an increase in osteoblast surface from 2.1% ± 3.0% to 6.0% ± 7.0% (p < 0.05), increased bone formation in men (21 ± 31 to 80 ± 96 μm2/mm2 p < 0.05) and serum osteocalcin increased from 2.3 ± 0.3 pg/ml before transplantation to 5.9 ± 1.8 pg/ml (p

The aim of this study was to quantitate T-cell populations infiltrating portal tracts, bile ducts and hepatic lobules in 82 biopsy specimens from 25 patients after orthotopic liver transplantation. Biopsy specimens taken immediately after revascularization of the graft were used as controls. Patients studied include 18 with initial rejection episodes, 11 with unresolved rejection, five with vanishing bile duct syndrome and eight patients with other forms of liver injury. Quantitation was done in a blinded fashion for the first 20 biopsy specimens. A double immunolabeling technique was used to simultaneously immunolabel bile duct structures (with anti-major histocompatibility complex class II or antikeratins) and lymphoid populations (with anti-CD2, anti-CD4 or anti-CD8). This facilitated the accurate quantitation of intraepithelial lymphocytes within bile ducts. This technique also enabled simultaneous detection of CD4 and CD8 antigens on lymphocytes in portal tracts. The predominant lymphocyte subtype within biliary epithelium during acute and chronic rejection was of the CD2+/CD8+ phenotype. CD8+/CD4+ ratio in bile ducts was approximately 5:1 in acute, unresolved and chronic rejection. In vanishing bile duct syndrome, double immunolabeling enabled the detection of destroyed interlobular bile duct remnants that were not apparent on routine hematoxylin and eosin staining. Attached to some of these structures were CD8+ lymphocytes. Lobular CD8+ cells were not prominent in acute rejection but increased significantly in biopsy specimens from patients with unresolved and chronic rejection. In chronic rejection, a selective increase was seen in these CD8+ cells in centrizonal regions.(ABSTRACT TRUNCATED AT 250 WORDS)

A 63 year old woman with liver failure received a transplant from a 21 year old male diagnosed as brain dead following a motor accident. After the operation, bile production was virtually absent and aspartate transaminase (AST) values rose dramatically 40 h postoperatively. Primary non-function of the graft was diagnosed, and the patient put on an urgent list for retransplantation. At the same time a continuous intravenous infusion of PGE1 was administered. Aspartate transaminase levels decreased within 9 h and reached normal levels by the sixth postoperative day, when bile production began to increase. Liver function subsequently returned to normal.

Recurrent hepatitis B virus (HBV) infection remains a major cause of morbidity and mortality after liver transplantation. Recently, antiviral therapy, such as lamivudine, has become available for prophylaxis against HBV reactivation posttransplantation and for the treatment of HBV recurrent disease. We report our initial experience with lamivudine therapy in patients with precore mutant-associated HBV infection undergoing liver transplantation (n = 29). Outcomes were compared in three patient groups: group 1, precore mutant HBV infection not receiving lamivudine (n = 10); group 2, recurrent precore mutant HBV infection posttransplantation subsequently treated with lamivudine (n = 10); and group 3, HBV precore mutant patients undergoing liver transplantation and receiving lamivudine and low-dose hepatitis B immune globulin (HBIG) from the time of transplantation (n = 9). In group 1, HBV recurred in 9 of 10 patients, with subsequent graft loss in all 9 patients. In group 2, all patients developed HBV recurrence at a mean of 7.3 months posttransplantation and started lamivudine therapy at a median of 16 months posttransplantation. Follow-up on lamivudine therapy was for a median of 11 months. Six of these 10 patients developed mutations in the HBV polymerase gene associated with lamivudine resistance. There were two liver failure-related deaths in this group. In group 3 patients, there was one death from graft-versus-host disease. The remaining 8 patients have been followed up for a mean of 15.6 months posttransplantation, and all remain hepatitis B surface antigen negative and HBV DNA negative. In conclusion, lamivudine therapy in association with low-dose HBIG is effective in preventing HBV reactivation posttransplantation. Rescue therapy with lamivudine in patients with HBV recurrence is only moderately effective, with a 60% lamivudine resistance rate in patients treated for longer than 6 months.

Cells from primary porcine hepatocytes (PPH) and the immortalized human hepatoma cell line C3A are both used in bioartificial liver support systems (BALSS). In this work the viability and metabolic capacity of PPH and C3A cells cultured in different media were compared. Also, because the cells come into direct or indirect contact with human blood components in BALSS, the effects of human complement on survival and functions of the cells was evaluated. For short-term culture, maintenance of PPH viability was essential for retention of P450IA1 activity ( r = 0.882, p < 0.01) and effective ammonia clearance ( r = −0.791, p < 0.01). When cell viability was below 60% P450IA1 activity could not be recorded and nitrogen elimination activity significantly diminished. In contrast to PPH, ammonia levels were markedly increased for C3A cells in all culture media tested ( p < 0.01). Ammonia increase correlated with C3A viability ( r = 0.896, p < 0.05). PPH metabolic function was superior to that of the C3A cell line when evaluated by P450IA1 activity, ammonia removal, and amino acid metabolism. When PPH were incubated in human plasma (HP) or human serum (HS) there was rapid and irreversible deterioration of viability occurring within 9 h. This toxic effect could be prevented by the inactivation of complement. When sodium citrate dissolved in dextrose was added to medium, there was considerable damage to both PPH and the C3A cell line. However, there was no demonstrable toxic effect when hepatic cells of either type were exposed to heparin. We conclude that PPH cultivated in complement-inactivated HP or HS are to be preferred to C3A for clinical application of BALSS, and that heparin should be preferred for anticoagulation in BALSS. © 1998 Elsevier Science Inc.

Carbon monoxide (CO) inhalation leads to cerebral, cardiac, and, more rarely, liver damage. The use of liver allografts from CO poisoned donors with evidence of liver damage has not previously been reported. In this report we describe two recipients, both in fulminant hepatic failure, who received liver grafts from such donors. One donor had markedly abnormal liver function tests (LFTS), and in the other LETS were mildly abnormal. In both, the liver appeared normal at procurement. There was satisfactory early function of both allografts, although marked patchy necrosis was seen on the postreperfusion biopsy (case 1), and on a 10 day postoperative biopsy (case 2). In both cases the changes were considered to be related to damage sustained from CO inhalation. Both allografts soon achieved normal function and both recipients are well. We conclude that CO poisoning can cause liver damage that can recover completely following liver transplantation.

Retransplantation for hepatitis B-related liver allograft failure is rarely successful. Recurrence of infection is almost universal, and the second allograft is invariably lost more rapidly than the first. In a recent multicenter study, only 1 of 20 hepatitis B virus (HBV)-positive patients who underwent liver retransplantation survived beyond 6 months. This report describes the long-term effect of antiviral therapy in a 56-year-old man who was retransplanted for HBV-related allograft loss 14 months after his initial liver transplant. He was treated after the second transplant with intravenous daily ganciclovir. After 10 months of this therapy HBV recurrence was detected. After a change to oral famciclovir therapy, there was a decrease in serum HBV DNA and amino-transferase levels and an improvement in the patient's clinical condition. Famiciclovir therapy has now been continued for 26 months, and the patient remains well 3 years after his second transplant, despite persistent HBV infection and progression to cirrhosis. These observations indicate that the use of long-term antiviral therapy offers promise for improving outcomes in patients who undergo retransplantation after HBV-related liver allograft failure.

• Occlusion of the supraceliac abdominal aorta and hepatic vascular isolation were employed in a series of 15 patients as a definitive method to allow avascular hepatic resection. The series was compared with an earlier group of patients treated conventionally. In the avascular hepatic resection group there was no mortality; hypotension did not occur at the time of hepatic vascular isolation; rapid, accurate excision of the hepatic lesions could be achieved in a bloodless field; resection of midline lesions and those involving the great veins was possible; and "segmentectomies," or resections crossing segmental boundaries, could be performed where previously formal hepatic lobectomies were required. Concomitantly, the greatest amount of uninvolved hepatic parenchyma remained in situ. There was increased ease of operative management, reduced blood loss, and reduced operating time (mean, 2.8 hours). ( Arch Surg . 1990;125:1482-1485)

Our group began a National Pilot Liver Transplantation Programme in January, 1986, for which this report documents the results of the first 15 months' work. Seventy potential recipients (55 adults, 15 children) were referred for consideration for liver transplantation either directly or by state selection committees that had been established in most Australian states. The most common conditions for referral of adults were chronic active hepatitis, primary sclerosing cholangitis and primary biliary cirrhosis; 11 patients had fulminant hepatic failure. In children, the most common condition for referral was biliary atresia. Twenty-nine (41%) patients were considered unsuitable candidates for liver transplantation, 25 patients (21 adults and four children) were accepted for transplantation at a later time, and 16 patients (11 adults and five children) were selected for immediate transplantation. Of these 16 patients, three patients died before a donor could be found. Of the 13 patients to receive transplants (one patient received two transplants), 10 patients (seven of nine adults; three of four children) are alive and well; nine patients have good liver function and one patient has impaired liver function. The additional costs of the Programme to the hospitals were estimated at approximately $2 million a year. It is concluded that for those persons who require liver transplantation in Australia, worthwhile survival after this procedure can be obtained.

A technic for auxiliary transplantation of the liver in man is detailed with a single case report of a patient who died four days after operation because of prolonged postoperative hypotension. The allograft is placed in the right paracolic gutter with the right lobe inferior and the hilum medial. The superior aspect of the allograft inferior vena cava is anastomosed to the recipient infrarenal inferior vena cava. The donor celiac axis is anastomosed to the front of the recipient aorta and the portal vein to the recipient superior mesenteric vein at the level of the duodenum. Biliary drainage is by a Roux-Y anastomosis of jejunum to the gallbladder. Advantages of the technic are that the site for the allograft may be prepared rapidly with decreased ischemic interval, the risk of postoperative respiratory complications and the threat of intra- and postoperative hemorrhage or thrombosis are decreased, and removal of the potentially harmful initial effluent from the ischemic allograft may be accomplished. Revascularization is physiologic in that portal inflow to the allograft is assured in the presence of portal hypertension.

Post-transplant acute renal failure in cadaver renal recipients treated with cyclosporine. The outcome of patients with acute renal failure following cadaveric renal transplant has been evaluated in a prospective, controlled trial, comparing treatment with cyclosporine (CSA) to prednisone, azathioprine, and antilymphocyte globulin (AZA). There was a high incidence of acute post-transplant renal failure in both groups: 37 of 51 CSA and 31 of 45 AZA patients, due to the long exposure of kidneys to warm and cold ischemia. Onset of adequate renal function was delayed for three or more weeks in 27 (53%) CSA and only nine (20%) AZA patients, and the only predisposing factor found was donor hypotension. All nine AZA and 18 of the 27 CSA patients with prolonged oliguria subsequently had a spontaneous diuresis. Nine of the CSA patients were changed to azathioprine and prednisone because of suspected CSA toxicity, and eight of these kidneys began functioning within days, even though they had been oliguric for 21 to 83 days. Of these nine patients, five had adequate long-term function on AZA, three developed CMV infections that were fatal to two individuals, and two rejected their grafts. Plasma CSA levels fluctuated widely in all patients, but were not higher in any group, including those with prolonged oliguria. During the oliguric period, biopsy specimens proved rejection was more common in the nine patients who had their CSA stopped than in the other CSA patients, and seven of these nine developed a diffuse interstitial fibrosis that was thought to be a manifestation of CSA toxicity. Extensive analysis of the post-transplant course showed rejection and CSA nephrotoxicity as the only probable causes of the delayed recovery from oliguria in the CSA group. Although CSA-treated patients tended to have higher serum creatinines, no significant differences were found at 12 months in any of the groups. Overall graft survival was similar in all groups.

Oral retinoid therapy has been considered for the prevention of skin carcinogenesis in humans, although animal studies have failed to provide any evidence of a protective effect of these drugs in the one-step photocarcinogenic system. In this study, oral therapy with vitamin A or a synthetic analogue, etretinate, was tested for ability to protect hairless mice (Skh-hr1) from the development of skin tumours following exposure to broad-band light (280-700 nm) for 25 weeks. Retinoids were given by gavage 3 times weekly either at low dosage (2000 IU vitamin A or 4 mg etretinate per kg body weight) or high dosage (10,000 IU vitamin A or 20 mg etretinate per kg body weight). None of the retinoid therapies compared to control mice (gavage vehicle only) modified skin tumour production in terms of time to onset of tumours, total tumour yield, or the types of tumours produced.

Extraanatomic bypass using polytetrafluoroethylene is a satisfactory alternative to direct aortic surgery in poor risk patients and in patients who have had previous aortoiliac reconstruction. If the disease is limited to one side, a crossover graft gives very satisfactory results with a 1 year cumulative patency of 95.6 percent. Axillofemoral grafts also give satisfactory results, especially if episodes of thrombosis are treated promptly by thrombectomy, in which case flow will be restored in most cases, with an overall 1 year cumulative patency of 89.5 percent.

Fine-needle aspiration biopsy specimens of renal transplants were analysed by means of commercially available monoclonal antibodies and an immunoperoxidase stain. Three cellular features associated with acute cellular rejection were identified—heavy infiltrates of activated T cells or large mononuclear cells strongly expressing HLA-DR antigens, and HLA-DR expression by renal tubular cells. A combination of semiquantitative scores for these features correctly identified rejection in 32 of 34 cases, with no false positives in cases of cyclosporin nephrotoxicity or stable graft function.

Immunopathology of renal allograft rejection analyzed with monoclonal antibodies to mononuclear cell markers. The composition of the mononuclear cell infiltrate in rejecting renal allografts was determined on 96 renal biopsies and 22 nephrectomy specimens by the use of monoclonal antibodies to mononuclear cell surface markers and an indirect immunoperoxidase staining technique. During rejection the composition of the infiltrate was heterogeneous, with T cells (T1l), monocytes (OKM1) and HLA-DR expressing mononuclear cells the most frequent sub-populations. B cells (Bl) and activated T cells, identified by OKT10, were always in the minority. The T cells infiltrate usually included the helper/inducer (T4) and cytotoxic (T8) subclasses, which suggests that both may contribute to the mediation of rejection. Whether T4 or T8 predominated in the graft did not relate to the ratio of T4:T8 in blood, the HLA A, B or DR incompatibilities of the graft, or the immunosuppressive used. The frequency of T1l, T4, T8, HLA-DR positive cells and monocytes, but not B cells, increased with the severity of rejection and was similar in biopsies from patients immuno-suppressed with Cyclosporine (CSA) to those given a combination of azathioprine, prednisone and antilymphocyte globulin (AZA). Severe rejection episodes which did not respond to treatment with corticosteroids were more often characterized by a predominance of T8 over T4 cells and T cells infiltrating the glomeruli. In grafts with evidence of cellular rejection, renal tubular cells were shown to have a marked increase in their expression of HLA-DR antigens compared to normal kidneys or grafts with minimal rejection. The expression of HLA-DR antigens on graft tubular cells correlated with the presence of T cells in the interstitium and the severity of rejection, except for moderate rejection in CSA treated biopsies, in which HLA-DR expression was lower than in AZA biopsies. These immunopathological studies have demonstrated that a variety of potential effector cells exist within the graft, and several features have been identified which may assist in assessing the prognosis of the rejection episode.

Prednisolone and antithymocyte globulin (ATG) were compared for their abilities to reverse acute rejection in cyclosporin A-treated canine graft recipients. Outbred dogs bearing kidney allografts were treated with a suboptimal dose of cyclosporin A (10 mg kg-1); at the onset of an acute rejection episode, animals received daily prednisolone (40 mg kg-1) or ATG (20 mg kg-1) until serum creatinine levels decreased. In seven untreated allograft recipients, rejection was first diagnosed at a mean 4.4 days post-transplant. In 23 dogs receiving cyclosporin A, rejection was first diagnosed in all dogs at a mean 43.6 days post-transplant. Compared to ATG, prednisolone was more successful in the reversal of primary acute rejection episodes (5/8 and 7/8 reversals, respectively) and produced a quicker return to normal renal function (mean 15.4 and 6.8 days, respectively). ATG therapy, however, resulted in fewer subsequent acute rejection episodes than prednisolone therapy (mean 1/5 and 6/7 developed secondary rejection episodes, respectively); the possible advantage of 'clonal depletion' following ATG therapy is discussed.

In 14 of 204 consecutive cadaveric renal allograft recipients, the primary diagnosis was essential hypertension. Four patients had manifest ischemic heart disease before transplantation. Three of these patients died within 31 months of transplantation from recurrent myocardial infarction, and the fourth experienced coronary insufficiency. Cadaveric renal transplantation does not prevent the progression of coronary artery disease in patients whose renal failure was due to essential hypertension. In the presence of angina or previous myocardial infarction, these patients may be better treated by maintenance hemodialysis. ( JAMA 235:2318-2320, 1976)

Fourteen porcine hepatic allografts were done using techniques designed for minimal damage to the allograft. Successful transplantation was achieved in ten; technical faults caused the four failures. Hepatocellular damage reflected by elevated SGOT levels became evident during perfusion and developed slowly after revascularization. Similar changes in lactic dehydrogenase (LDH) levels were not found. Potassium efflux during cold perfusion appeared to be related not to damage, but to reversible changes in membrane potential and enzyme activity induced by hypothermia. Interference with hepatic synthesis of plasma proteins and cholesterol was observed. The depression of cholesterol levels was short-lived in comparison with that of plasma protein.

Eleven do kidneys were removed in Los Angeles, preserved, and air-freighted in small insulated boxes to London, Tel Aviv and Sydney. They were allografted into bilaterally nephrectomized dogs after storage periods of 14 to 23 hours. Except in the case of one technical failure, the rise in serum creatinine in the recipients was minimal, reaching on the average 2.2 ± SD 0.5 mg/100 ml. This simple method of preservation, involving flushing with a new perfusate and storage in ice, could provide a solution to the problem of transporting cadaver kidneys to histocompatible recipients. Survival of two out of three kidneys stored for 48 hours was also obtained.

Venous thrombosis continues to represent a troublesome and even fatal complication of a variety of medical and surgical disorders. Numerous methods of treatment have been employed in both the prevention and the management of this condition, but it is generally agreed that much yet remains to be done in the satisfactory solution of this difficult problem. In the recent past direct thrombectomy has been advocated for acute and chronic venous occlusion. This has been employed in the femoral and iliac vessels particularly, and encouraging results have been reported by several observers. 1,2 In the present study an attempt has been made to devise a reliable method for the production of experimental thrombosis in large veins and to follow the natural history of such lesions with an investigation of the results following thrombectomy. Methods Twelve mongrel dogs (10-20 Kg.) were employed. Following premedication with morphine (1.25 mg. per kilogram) and chlorpromazine

A technique for orthotopic liver transplantation was used in 13 pigs, with 9 survivors. It incorporated rapid hepatic cooling at the time of donor death, continuous perfusion of the liver during hepatectomy and transplantation, rewarming of the allograft with oxygenated solution before revascularization with arterial blood shunted to the portal vein, early reestablishment of inferior vena caval flow and completion, and securing and release of each of the vascular anastomoses in turn. By these maneuvers the allograft was maintained cold and oxygenated for the entire ischemic interval, the anhepatic interval for the recipient and ischemic interval for the allograft were reduced, hypotension at the time of revascularization was prevented, and the threat of serious blood loss when multiple anastomoses are released simulatneously was eliminated.

Efficient preservation of the donor liver during hepatic transplantation is of crucial importance. Good function of the liver is required immediately after transfer if the patient is to survive liver excision and replacement, because there is no effective means of support in the absence of hepatic function. With auxiliary liver transplantation good function is again required at an early time to reverse the effects of advanced liver failure. Nevertheless, in this situation, the recipient's own liver may retain sufficient function in the early postoperative period to allow the allograft to recover from temporary damage which occurs at the time of transplantation. Laboratory experiments in dogs have shown that at normothermia the ischemic liver becomes unsuitable for transplantation after 20 to 30 minutes.1If the donor is cooled to 30 C before death and the liver perfused from the time of death with cooled electrolyte solution, this time may be