Metzenbaum-assisted liver resection: a safe and effective liver resection technique

AIM

We hereby present and evaluate a technique for hepatic parenchymal transection based on the application of Metzenbaum scissors and clips during liver ischemia.

METHODS

Our technique was retrospectively evaluated in 32 noncirrhotic, noncholestatic patients with intrahepatic cholangiocarcinoma and 32 patients with hepatocellular carcinoma (23 of whom cirrhotic, 71.9%). Patient data were retrieved from our Hepatobiliary Surgery Database. Type and duration of vascular clamping, blood transfusion requirements, marginal status and immediate postoperative complications were analyzed.

RESULTS

Twenty-seven extended (>4 liver segments; 42.2%) and 37 nonextended (≤4 liver segments; 57.8%) liver resections were analyzed. Warm liver ischemia duration was 14 (interquartile range: 11-17.8) min. Thirty-three patients (51.6%) were transfused with a median of 2 (1.5-3) units of packed red blood cells. Tumor-free margins were achieved in 90.6% of cases (n = 58). The overall morbidity rate was 18.8% with a 4.7% mortality rate. Our technique allowed for excellent identification and safe dissection and preservation, or ligation of major liver vessels.

CONCLUSIONS

The proposed technique is simple, fast, safe and with low cost. It is associated with limited postoperative complications while from an oncologic standpoint it enables the surgeon to achieve a high percentage of tumor-free margins while protecting major vascular structures.

Liver transplantation for intrahepatic cholangiocarcinoma

The indication of liver transplantation for intrahepatic cholangiocarcinoma (ICC) is highly controversial. Initially, liver transplantation was embraced as a promising treatment for ICC, providing both a wider surgical margin and a potential cure for the underlying liver disease. However, the majority of transplant centers have abandoned liver transplantation for ICC due to poor long-term survival and high recurrence rates. Interestingly, these decisions were based on studies with highly inconsistent outcomes due to a limited number of patients, various patient selection criteria, and the use of nonstandardized adjunctive therapy protocols. Indeed, recent studies have revealed that ICC patients with small solitary tumors have excellent long-term survival after liver transplantation. Moreover, as seen in early-stage hilar cholangiocarcinoma, neoadjuvant and adjuvant therapy hold promise for improved long-term survival in patients with locally advanced ICC. As we work to expand treatment options for ICC, further evidence of success in this area is needed in order to justify the use of limited organ resources to treat ICC. Continued efforts to improve diagnosis of ICC, hone patient selection criteria, and implement standardized treatment protocols could provide certain patients with ICC access to potentially life-saving liver transplantation.

Split liver transplantation using Hemiliver graft in the MELD era: a single center experience in the United States

Under the "sickest first" Model for End-Stage Liver Disease (MELD) allocation, livers amenable to splitting are most often allocated to patients unsuitable for split liver transplantation (SLT). Our experience with SLT using hemilivers was reviewed. From April 2004 to June 2012, we used 25 lobar grafts (10 left lobes and 15 right lobes) for adult-sized recipients. Twelve recipients were transplanted with primary offers, and 13 were transplanted with leftover grafts. Six grafts were shared with other centers. The data were compared with matched whole liver grafts (n = 121). In 92% of donors, the livers were split in situ. Hemiliver recipients with severe portal hypertension had a greater graft-to-recipient weight ratio than those without severe portal hypertension (1.96% vs. 1.40%, p < 0.05). Hemiliver recipients experienced biliary complications more frequently (32.0% vs. 10.7%, p = 0.01); however, the 5-year graft survival for hemilivers was comparable to whole livers (80.0% vs. 81.5%, p = 0.43). The secondary recipients with leftover grafts did not have increased incidences of graft failure (p = 0.99) or surgical complications (p = 0.43) compared to the primary recipients. In conclusion, while routine application is still controversial due to various challenges, hemiliver SLT can achieve excellent outcomes under the MELD allocation.

Intrahepatic blood flow redistribution after temporary occlusion of the middle hepatic vein during right lobe liver donation: report of a case

INTRODUCTION

One of the critical factors that influence graft function after live donor liver transplantation is the presence or absence of global or sectorial liver congestion. Many authors advocate for routine middle hepatic vein (MHV) reconstruction because it is often difficult to determine when the MHV or one of its major branches have functional significance. Predictive tests to assess hemodynamic and functional significance of the MHV and its tributaries are still under study.

CASE REPORT

We have described a novel intraoperative manipulation and Doppler ultrasonographic evaluation that led to the decision to include the MHV with the right lobe graft.

Right hepatectomy for living donation: role of remnant liver volume in predicting hepatic dysfunction and complications

BACKGROUND

Extensive attention has been placed on remnant liver volume (RLV) above other factors to ensure donor safety.

METHODS

We performed a retrospective review of 137 right hepatectomies in live donors between June 1999 and November 2010.

RESULTS

Median right lobe volume was 1,029 cm(3), which correlated with its actual weight (r = 0.63, P < .01); median RLV was 548 cm(3). Of the donors, 32 (24%) developed postoperative hepatic dysfunction (bilirubin >3 mg/dL or prothrombin time >18 s on postoperative day 4). RLV did not predict postoperative hepatic dysfunction (P = .9), but it was associated with peak international normalized ratio (INR) (P = .04). Donor age and male gender were predictors of increased bilirubin at postoperative day 4 (age, P = .03; gender, P = .02). Of the donors, 45 (33%) experienced complications, and 24 donors had RLVs <30%; 42% experienced complications compared to 31% of donors whose RLVs were greater than 30% (P = .3). Cell-saver utilization and aspartate-aminotransferase (AST) levels (OR = 3) were associated with complications. Volumetric assessment can predict RLV accurately.

CONCLUSION

Although no demonstrable association between RLV <30% and complications was found, an RLV of 30% should remain the threshold for donor safety. Age and gender should be balanced in donors with a near threshold RLV of 30%. Surgical complexity, suggested by the need for intraoperative autoinfusion of blood and postoperative levels of AST, remained the independent predictor of complications.

Splenic artery embolization for the treatment of refractory ascites after liver transplantation

Refractory ascites (RA) is a challenging complication after orthotopic liver transplantation. Its treatment consists of the removal of the precipitating factors. When the etiology is unknown, supportive treatment can be attempted. In severe cases, transjugular intrahepatic portosystemic shunts, portocaval shunts, and liver retransplantation have been used with marginal results. Recently, splenic artery embolization (SAE) has been described as an effective procedure for reducing portal hyperperfusion in patients undergoing partial or whole liver transplantation. Here we describe our experience with SAE for the treatment of RA. Between June 2004 and June 2010, 6 patients underwent proximal SAE for RA. Intraoperative flow measurements, graft characteristics, embolization portal vein (PV) velocities before and after SAE, and spleen/liver volume ratios were collected and analyzed. The response to treatment was assessed with imaging (ultrasound/computed tomography) and on the basis of clinical outcomes (weight changes, diuretic requirements, and the time to ascites resolution). The PV velocity decreased significantly for each patient after the embolization (median = 66.5 cm/second before SAE and median = 27.5 cm/second after SAE, P < 0.01). All patients experienced a significant postprocedural weight loss (mean = 88.1 ± 28.4 kg before SAE and mean = 75.8 ± 28.4 kg after SAE, P < 0.01) and a dramatic decrease in their diuretic requirements. All but 1 of the patients experienced a complete resolution of ascites after a median time of 49.5 days (range = 12-295 days). No patient presented with postembolization complications. In conclusion, SAE was effective in reducing the PV velocity immediately after the procedure. Clinically, this translated into a dramatic weight loss, a reduction of diuretic use, and a resolution of ascites. SAE appears to be a safe and effective treatment for RA.

Production and immunological responses associated with controlled-release-capsule vs 5-drench preventive anthelmintic programmes for parasite control in lambs

AIMS

To determine whether: a) using a controlled-release anthelmintic capsule (CRC) instead of a programme of 5 oral drenches administered at 3-4 week intervals, would delay the development of anti-parasite immunity in lambs; b) the use of ivermectin instead of albendazole, administered either as a CRC or as a programme of 5 oral drenches, would delay the development of anti-parasite immunity in lambs; c) lambs treated with CRCs would have higher liveweight gains than lambs drenched orally 5 times at 3-4 week intervals, and; d) delayed onset of anti-parasite immunity is associated with reduced liveweight gains in the period following anthelmintic treatment.

METHODS

Three field trials were conducted, 1 on a research farm and 2 on commercial sheep farms, in which groups of 30 lambs were treated with either a CRC containing albendazole, a CRC containing ivermectin, 5 oral drenches with albendazole, or 5 oral drenches with ivermectin, administered at 3-4 week intervals. Liveweights and faecal nematode egg counts (FECs) were recorded in all trials. Immunoglobulin-G (IgG) antibody levels to Ostertagia circumcincta and Trichostrongylus colubriformis adult and larval antigens were measured in Trials 1 and 3, and fleece weights and resistance of animals to nematode challenge infection were measured in Trial 1.

RESULTS

CRC-treated lambs had higher levels of antibodies to O. circumcincta infective-stage larvae (L3) than orally drenched lambs in Trial 3, but no other immunological differences due to mechanism of delivery were detected. Antibody levels were lower in lambs treated with ivermectin than albendazole, as a CRC or oral drench in Trial 1, but this was not associated with any measurable effects on FEC or productivity. No significant differences (p>0.05) were detected between drench types (albendazole vs ivermectin) or delivery mechanisms (CRC vs oral drenching) in any of the production parameters measured, in any of the trials. Albendazole-CRCs failed to control FECs in all 3 trials.

CONCLUSIONS

Although some differences between treatments in antibody levels were detected these were not associated with measurable differences in level of parasitism or productivity of lambs. CRC use did not appear to offer substantial gains in productivity over a structured programme of 5 oral drenches administered at 3-4 week intervals.

Selective and on-demand drenching of lambs: Impact on parasite populations and performance of lambs

AIM

To determine whether drenching regimes for lambs by which a proportion (10%) of the heaviest animals was selectively left untreated, or animals are only drenched 'on demand' when faecal nematode egg counts (FEC) exceeded a threshold level, would result in measurable increases in parasite larval challenge in the autumn and/or decreases in the performance of lambs.

METHODS

A replicated study compared three drenching strategies in which mobs of lambs (n=360 in total) received either: a five-drench preventive programme, administered to all animals (Treatment 1); a five-drench preventive programme, but the 10% heaviest animals left untreated each time (Treatment 2); or drench treatments administered only when FEC exceeded 500 eggs per gram of faeces (epg) (Treatment 3). After the five-drench programme, animals in Treatments 1 and 2 were treated according to FEC as for Treatment 3. A triple-combination drench containing ivermectin, oxfendazole and levamisole, administered orally, was used for all treatments. There were nine farmlets, allowing three replicates of each treatment, in a completely randomised design. Parasite infestations on pasture were measured in autumn by pasture plucks, and worm burdens were monitored in tracer lambs, while the performance of lambs was assessed by liveweight gains, fleece weights, and body condition and dag scores.

RESULTS

Increased numbers of Haemonchus contortus and Trichostrongylus colubriformis larvae on pasture were found in the autumn on farmlets treating selectively or on-demand (Treatments 2 and 3). No differences were detected in other parasite species. Mean liveweight gains did not differ between treatments but some differences were detected between drenched and undrenched lambs in Treatment 2. Mean body condition and mean dag scores of lambs in Treatment 3 tended to be lower and higher, respectively, than those of lambs in Treatment 1; Treatment 2 was generally intermediate.

CONCLUSIONS

Drenching strategies for lambs designed to slow the development of anthelmintic resistance, by increasing the pool of susceptible worms available to dilute resistant survivors after treatment, resulted in increased numbers of H. contortus and T. colubriformis but not other species of parasite on pasture. The increased parasite challenge to lambs in the autumn was associated with small production losses, which may be acceptable to farmers wishing to implement such strategies. It is clear that further work is required on the interaction between management practices and the population dynamics of parasites, especially with regard to creating pools of susceptible genotypes to slow the development of drench resistance.

Drenching adult ewes: Implications of anthelmintic treatments pre- and post-lambing on the development of anthelmintic resistance

AIMS

To test the hypothesis that peri-parturient anthelmintic treatment of adult ewes, either pre-lambing with a controlled- release capsule (CRC) or at tail-docking with a short-acting oral formulation, would increase the rate of development of anthelmintic resistance, as compared to not drenching ewes and giving an additional drench to lambs in the autumn. Also, to evaluate the potential of routinely leaving 15% of the heaviest lambs untreated when drenching, as a means of slowing the development of anthelmintic resistance.

METHODS

A replicated farmlet trial was run from 1999- 2004. Eleven farmlets, each consisting of five paddocks, were initially seeded with Ostertagia (=Teladorsagia) circumcincta and Trichostrongylus colubriformis parasites, these being a mixture of albendazole-susceptible and -resistant isolates to yield a 96% reduction in faecal nematode egg count (FEC) on drenching. Four prescriptive drenching regimes were applied; Treatments 1-3 were replicated three times and Treatment 4 twice. Treatments were as follows. Treatment 1: Ewes were given an albendazole CRC pre-lambing, and any ewes exceeding 65 kg liveweight were given two capsules simultaneously; lambs were given a five-drench preventive programme of treatments, orally, of albendazole on Days 0, 21, 42, 70 and 98 after weaning. Treatment 2: Ewes were given a single oral treatment of albendazole at docking (2-3 weeks after lambing), and lambs were given the same five-drench preventive programme as in Treatment 1. Treatment 3: Ewes remained untreated, while lambs were given a six-drench preventive programme of treatments, orally, of albendazole on Days 0, 21, 42, 70, 98 and 126 after weaning. Treatment 4: Ewes remained untreated, while lambs were given the same six-drench preventive programme as in Treatment 3, but the heaviest 15% of lambs were left untreated each time. Albendazole-resistance status was measured at least twice-yearly, using faecal egg count reduction tests (FECRTs) and larval development assays (LDA). In addition, controlled slaughter of drenched and undrenched tracer lambs was undertaken in the last 3 years.

RESULTS

Resistance to albendazole increased most rapidly in Treatment 1, as measured by FECRT and LDA results, and worm burdens in tracer lambs. In Treatment 2, resistance developed slower than in Treatment 1 but faster than in Treatments 3 and 4, as measured by LDA; resistance in Treatment 2 developed more quickly than in Treatment 4, as measured by FECRTs. There was no significant difference between Treatments 3 and 4, although this approached significance in Ostertagia spp, as measured by LDA.

CONCLUSIONS

Anthelmintic treatments to adult ewes around lambing time are likely to be more selective for resistance than additional treatments administered to lambs in the autumn. Farmers wishing to slow the emergence of anthelmintic resistance on their farms should look to minimise the administration of peri-parturient treatment of ewes. A trend to slower development of resistance where a proportion of lambs were left untreated at each drench suggests further work on this aspect of management of resistance is warranted.

How repeatable is a faecal egg count reduction test?

AIM

To gather information on the repeatability of a faecal nematode egg count (FEC) reduction (FECR) test (FECRT), evaluating both different methods of calculating efficacy and variations within a method, in order to supply veterinarians and other advisors with sufficient information to apply some level of confidence around a diagnosis of anthelmintic resistance based on FECRT results.

METHODS

Two commercial sheep farms were selected on the basis of having previously recorded FECR <95% after treatment with ivermectin (Farm 1) or albendazole (Farm 2). On each farm at least 250 lambs, managed as a single mob, were individually ear-tagged and sampled for FEC. The resulting counts were used, 3-4 days later, to sort the lambs into 24 groups of 10. First, the animals were split into three groups of 80, having high, medium or low FEC. Second, within each of these groups the 80 animals were further divided into four replicate mobs of 20 (each with the same mean count). Third, each of these replicates was further split into two groups of 10: those that would be drenched and those that would remain as untreated controls. All animals were again faecal-sampled and those in the drenched groups were dosed, using a syringe, to their individual liveweight, with ivermectin (Farm 1) or albendazole (Farm 2). Ten days after treatment all animals were individually faecal sampled again. FEC and larval cultures were undertaken for all 24 groups from both pre- and post-treatment samples. Efficacy (FECR) of the undifferentiated FECRT was calculated using three different equations, and efficacy by genus was also calculated.

RESULTS

Calculated efficacies differed between equations, and the equation which did not utilise an untreated control yielded significantly lower efficacy estimates on both farms. Faecal cultures varied considerably in the proportions of parasite genera recovered. In general, this did not differ between FEC groups, except on Farm 1 where Haemonchus spp were more common and Cooperia spp less common in high-FEC samples. Estimated efficacies against individual genera varied considerably or very little, depending on the level of resistance. On both farms, differing proportions of tests against some genera passed or failed FECRTs based on a threshold pass mark of > or =95% FECR.

CONCLUSION

There was considerable variability in the outcomes of FECRTs and in larval culture results. Caution is warranted in interpreting the results of FECRTs when efficacy values fall into the 90-95% range. Further, the possibility of a test returning a false-negative result is raised, indicating that even an efficacy estimated > or =95% may not guarantee the absence of resistant parasites.

Use of tissue plasminogen activator in liver transplantation from donation after cardiac death donors

Ischemic-type biliary stricture (ITBS) occurs in up to 50% after liver transplantation (LT) from donation after cardiac death (DCD) donors. Thrombus formation in the peribiliary microcirculation is a postulated mechanism. The aim was to describe our experience of tissue plasminogen activator (TPA) administration in DCD-LT. TPA was injected into the donor hepatic artery on the backtable (n = 22). Two recipients developed ITBS including one graft failure. Although excessive postreperfusion bleeding was seen in 14 recipients, the amount of TPA was comparable between those with and without excessive bleeding (6.4 ± 2.8 vs. 6.6 ± 2.8 mg, p = 0.78). However, donor age (41 ± 12 vs. 29 ± 9 years, p = 0.02), donor BMI (26.3 ± 5.5 vs. 21.7 ± 3.6 kg/m(2) , p = 0.03), previous laparotomy (50% vs. 0%, p = 0.02) and lactate after portal reperfusion (6.3 ± 4.6 vs. 2.8 ± 0.9 mmol/L, p = 0.005) were significantly greater in recipients with excessive bleeding. In conclusion, the use of TPA may lower the risk of ITBS-related graft failure in DCD-LT. Excessive bleeding may be related to poor graft quality and previous laparotomy rather than the amount of TPA. Further studies are needed in larger population.

Surgical resection for advanced gallbladder carcinoma. The Mount Sinai experience

BACKGROUND/AIMS

Advanced gallbladder cancer (GC) carries dismal prognosis, due to its extent at diagnosis and the low R0 resection performance rate.

METHODOLOGY

Thirty-two GC patients referred to our Department with an intention to treat between 1993 and 2005. All patients had advanced T stage (> or = T3). Pathological findings, surgical procedures and survival data were analyzed.

RESULTS

Seventeen radical procedures (16 hepatectomies and 1 cholecystectomy with common bile duct resection), 4 palliative procedures (12.5%) and 11 surgical explorations (34.4%) were performed (53.1%, resectability rate). Hepatectomies were performed with 0% mortality, 11.8% morbidity and 94.1% resectability rate. The respective 1-, 3- and 5- year survival rates were 71.4%, 28.6% and 14.3%. Radical lymph node dissection (p = 0.03), absence of perineural tumor invasion (p = 0.03) and patients' age <70 years (p < 0.01) were non-independently associated with favorable prognosis in the hepatectomy-treated group of GC patients.

CONCLUSIONS

GC patients with stage > or = IIA should be treated with hepatectomy combined with radical lymphadenectomy in order to achieve better staging and disease control. Incorporating the caudate lobe, more than 4 liver segments, or part of the extrahepatic biliary tree in the resection specimen in selected patients, might help eliminate perineural metastatic spread and achieve improved overall survival.

Is impaired hepatic arterial buffer response a risk factor for biliary anastomotic stricture in liver transplant recipients?

BACKGROUND

Blood flow to the liver is partly maintained by the hepatic arterial buffer response (HABR), which is an intrinsic autoregulatory mechanism. Temporary clamping of the portal vein (PV) results in augmentation in hepatic artery flow (augHAF). Portal hyperperfusion impairs HAF due to the HABR in liver transplantation (LT). The aim of this study is to examine the effect of the HABR on biliary anastomotic stricture (BAS).

METHODS

In 234 cadaveric whole LTs, PV flow (PVF), basal HAF, and augHAF were measured intra-operatively after allograft implantation. All recipients with a vascular complication were excluded. Buffer capacity (BC) was calculated as (augHAF - basal HAF)/PVF to quantify the HABR. Recipients were divided into 2 groups based on their BC: low BC (<0.074; n = 117) or high BC (> or =0.074; n = 117).

RESULTS

Of the 234 recipients, 23 (9.8%) had early BAS (< or =60 days after LT) and 18 (7.7%) had late BAS (>60 days after LT). The incidence of late BAS and bile leakage was similar between the groups; however, the incidence of early BAS in the low BC group was greater than that in the high BC group (15% vs 5.1%; P = .0168). In the multivariate analysis, low BC (P = .0325) and bile leakage (P = .0002) were found to be independent risk factors affecting early BAS.

CONCLUSION

Recipients with low BC who may have impaired HABR are at greater risk of early BAS after LT. Intraoperative measurements of blood flow help predict the risk of BAS.

Carbendazim, at concentrations used on pasture for facial eczema control, reduces development of Trichostrongylus colubriformis when sprayed onto infected sheep faeces

AIM

To determine whether the fungicide, carbendazim, as applied to pastures for controlling facial eczema (FE), would inhibit development of the free-living stages of the gastrointestinal nematode parasite Trichostrongylus colubriformis.

METHODS

Two studies were conducted, using sheep faeces containing eggs of T. colubriformis. In the first, the faeces were either exposed or not to an application of carbendazim sprayed at the recommended rate for FE control. After spraying, dishes containing the faeces were incubated at 20 degrees C for 14 days, and the resulting third-stage infective larvae (L3) extracted by baermannisation and counted. In addition, naturally infested pasture was also sprayed, and the number of L3 present 7 days later was assessed by cutting herbage samples and extracting larvae by soaking in water and baermannisation. In the second, the faeces were incubated at 20 degrees C for 0, 3 or 7 days before being exposed to no, one or two applications of carbendazim. After further incubation for 14, 11 or 7 days, L3 were similarly extracted by baermannisation and counted.

RESULTS

In the first study, there was a 74% reduction in the number of T. colubriformis larvae recovered from faeces exposed to carbendazim compared with faeces not exposed, but there was no reduction in the number of L3 recovered from herbage. In the second study, faeces incubated for 0 or 3 days prior to exposure to a single application of carbendazim yielded 98% or 89% fewer larvae, respectively, than faeces not exposed. Faeces incubated for 7 days prior to exposure yielded similar numbers of larvae to faeces not exposed.

CONCLUSION

Treatment of pastures with carbendazim for FE control is likely to result in reduced development of the larvae of T. colubriformis, and by inference those of other species, where the application coincides with the presence of freshly deposited faeces containing eggs and developing larvae. However, no effect of treatment on L3 was indicated. The significance of this for on-farm nematode parasite control remains to be determined, as does any potential for strategic applications of carbendazim to pasture aimed at reducing numbers of parasite larvae on pasture. The latter should not be contemplated without due consideration of the implications for the development of anthelmintic resistance.

Side-to-side cavocavostomy with an endovascular stapler: Rescue technique for severe hepatic vein and/or inferior vena cava outflow obstruction after liver transplantation using the piggyback technique

Venous outflow obstruction is a rare but potentially lethal complication after orthotopic liver transplantation (OLT) with the "piggyback" technique. Therapeutic options include angioplasty with or without stent placement, surgical reconstruction of the venous anastomosis, and retransplantation. Surgical options are technically very challenging and the outcomes discouraging. We describe here two cases of venous outflow obstruction in recipients of piggyback liver grafts, one involving both the vena cava and hepatic veins and the other affecting only hepatic vein outflow. Both patients were treated successfully with side-to-side cavo-cavostomy using an endovascular (endo-GIA) stapler. This novel technique is fast and effective in resolving the outflow obstruction.

Brave or gullible: testing the concept that leaving susceptible parasites in refugia will slow the development of anthelmintic resistance

AIM

To test the theory that creating a reservoir of unselected worms by leaving a proportion of lambs in a flock untreated with anthelmintic, i.e. in refugia, will slow the development of anthelmintic resistance in nematode parasite populations.

METHODS

Newly weaned Romney lambs (n=180) were infected with two nematode parasite species, Teladorsagia (= Ostertagia) circumcincta and Trichostrongylus colubriformis. For each species, the challenge doses contained a mixture of infective larvae from benzimidazole-resistant and -susceptible isolates calculated to yield, from the combined population, a 95% reduction in faecal nematode egg counts (FEC) following treatment with albendazole. Once the infections were patent, the lambs were divided into nine groups of 20 animals, and each group was allocated to one of three treatments. In Treatments 1, 2 and 3, 100%, 90% and 80% of animals were treated with an anthelmintic, respectively. For treatments 2 and 3, the heaviest animals remained untreated. Following treatment, each group was moved to its own previously prepared low-contamination pasture. Lambs grazed this pasture for 7 weeks before again being treated and moved to new low-contamination pastures (Shift 1 and Shift 2). The parasite populations on pasture resulting from the different treatments were subsequently sampled using tracer lambs, and worm eggs derived from these were used in both egg-hatch assays (EHA) and larval development assays (LDA), to measure albendazole-resistance status.

RESULTS

Treating all animals each time the groups were moved to new low-contamination pastures resulted in higher levels of albendazole resistance (p<0.05), measured using EHA and LDA, in subsequent parasite generations than when either 10 or 20% of animals were left untreated. However, higher FEC in the tracer lambs grazed on pastures in Treatments 2 and 3, compared with Treatment 1, indicated an increased level of pasture contamination as a result of leaving some animals untreated.

CONCLUSIONS

The results demonstrate that creating a reservoir of unselected parasites slows the development of anthelmintic resistance, and emphasises the risk of treating all animals prior to a shift on to low-contamination pasture. However, higher levels of pasture contamination, resulting from untreated animals, indicate the difficulty in managing both worm control and resistance.

The Mount Sinai experience with orthotopic liver transplantation for benign tumors: brief report and literature review: case reports

Orthotopic liver transplantation (OLT) is performed for benign hepatic lesions that are symptomatic, too large to be resected, have a malignant transformation potential, cause debilitating/life-threatening manifestations, or in patients experiencing posthepatectomy acute liver failure. Among benign tumors, polycystic liver disease (PLD) is the most common indication for OLT alone, or combined liver-kidney transplantation. Our 10-year experience with OLT for benign tumors includes two patients with PLD and one with a benign giant fibrous tumor. In this report, we present our experience with OLT for benign liver tumors, commenting on relevant published studies.