In most social ungulate species, males are larger than females and the sexes live in separate groups outside the breeding season. It is important for our understanding of the evolution of sociality to find out why sexual segregation is so widespread not only in ungulates but also in other mammals. Sexual body size dimorphism was proposed as a central factor in the evolution of sexual segregation in ungulates. We tested three hypotheses put forward to explain sexual segregation: the predation-risk, the forage-selection, and the activity budget hypothesis. We included in our analyses ungulate species ranging from non-dimorphic to extremely dimorphic in body size. We observed oryx, zebra, bighorn sheep and ibex in the field and relied on literature data for 31 additional species. The predation-risk hypothesis predicts that females will use relatively predator-safe habitats, while males are predicted to use habitats with higher predation risk but better food quality. Out of 24 studies on different species of ungulates, females and their offspring chose poorer quality but safer habitat in only eight cases. The forage-selection hypothesis predicts that females would select habitat based on food quality, while males should prefer high forage biomass. In fact, females selected higher quality food in only six out of 18 studies where males and females segregated, in eight studies there was no difference in forage quality and in four studies males were in better quality habitat. The activity budget hypothesis predicts that with increasing dimorphism in body size males and females will increasingly differ in the time spent in different activities. Differences in activity budgets would make it difficult for males and females to stay in mixed-sex groups due to increased costs of synchrony to maintain group cohesion. The predictions of the activity budget hypothesis were confirmed in most cases (22 out of 23 studies). The heavier males were compared to females, the more time females spent foraging compared to males. The bigger the dimorphism in body mass, the more males spent time walking compared to females. Lactating females spent more time foraging than did non-lactating females or males. Whether species were mainly bulk or intermediate feeders did not affect sexual differences in time spent foraging. We conclude that sexual differences in activity budgets are most likely driving sexual segregation and that sexual differences in predation risk or forage selection are additive factors.

Animals↗

PubMed2002

Concept for modular extracorporeal liver support for the treatment of acute hepatic failure.

Acute liver failure has a poor prognosis. The introduction of liver transplantation as a therapeutic option reduced mortality to 20-40%.With the growing disparity between the number of organ donations and the number of patients waiting for liver transplantation, efforts have been made to optimize the allocation of organs and to design extracorporeal methods to support the failing liver. The modular extracorporeal liver support is a concept for the treatment of hepatic failure. The CellModule is a multicompartment bioreactor for extracorporeal liver support therapy. The construction provides efficient integrated oxygenator functions and decentralized mass transfer is effected by a woven array of capillary systems. The bioreactor promotes primary human liver cells to spontaneous neo-formation of liver sinusoidal structures in vitro. Small capillary subunits, in which interwoven membrane links represent the liver lobuli, are simultaneously perfused. The used cell mass of 400-600 g enabled the clinical application of a liver lobe equivalent hybrid organ. The DetoxModule enables albumin-dialysis for removal of albumin-bound toxins; a DialysisModule for continuous veno-venous hemofiltration can be added to the system, in the case of hepato-renal failure.

Humans↗

PubMed2002

[Arterial port-catheter dislocation into the duodenum].

Arterial port-catheter dislocations into the duodenum are rare complications. We report on a 64-year-old male with sigmoid-resection for carcinoma, left hemihepatectomy and arterial port-catheter implantation into the common hepatic artery for liver metastases in both lobes and partial dislocation of the port system into the duodenum. Therefore, the port-catheter system had to be explanted after 8 cycles of cytostatic therapy and the duodenum had to be closed by a suture. Six months after surgery the patient felt well, a new singular metastasis in the right liver lobe could be treated successfully by laserinduced thermotherapy. At present the patient has no evidence for another metastasis.

Catheters, Indwelling↗

PubMed2002

[Spontaneous rupture of hepatic focal nodular hyperplasia--a rare cause of acute intraabdominal bleedingf].

Benign hepatic mass lesions are rare. Haemangioma, focal nodular hyperplasia and hepatocellular adenoma represent the most common ones. For the reason of serious clinical complications and potential malignant transformation of hepatic adenoma, surgical resection is the therapy of choice. Unlike adenoma focal nodular hyperplasia is mostly asymptomatic and rarely causes severe complications. We report on a spontaneous rupture and life-threatening intraperitoneal haemorrhage of a large, asymptomatic FNH, where surgical resection was indicated. Within three month after hepatic resection and after termination of oral contraceptives almost complete regeneration of liver tissue and dramatic regression of a second FNH lesion was apparent. Although haemorrhage of hepatic FNH is extremely rare, this case highlights the small risk of rupture in large lesions.

Adult↗

PubMed2002

[Acute liver failure following the use of ecstasy (MDMA)].

The use of "ecstasy" (Methylenedioxymethamphetamine) as a recreational drug is increasing in europe since the 1980's. Aside intended psychological effects the use of ecstasy can be followed by symptoms of intoxication; complications include toxic hepatic damage up to acute hepatic failure. This case-report is about a 17-year old female patient who regularly used "ecstasy" over a six-month period. Two days after the last use of "ecstasy", she reported to her general practitioner with nausea, vomiting, abdominal pain and jaundice. Within 10 days the patient developed acute liver failure. With criteria for liver transplantation fulfilled she was listed for orthotopic liver transplantation of high urgency which was carried out only one day later. Histological examination of the explanted liver showed evidence for a toxic fulminant hepatitis. After transplantation the patient made a full recovery and was released from hospital on day 26 after transplantation. At the first control after six months the patient was in good physical and nutritional condition, serological parameters were normal and ultrasound examination of the transplanted liver was unremarkable. The ethiopathology of "ecstasy"-induced hepatotoxicity, which can occur dose-independently with a symptom-free period from days to weeks after ingestion is not yet fully understood. Possible mechanisms of hepatic damage include influence of MDMA on body temperature regulation, harmful effects of the substance or further components of the "ecstasy"-tablets on the liver cell or a genetic vulnerability of some individuals against amphetamines and amphetamine derivates. There are no parameters existing which could predict the course and severity of "ecstasy"-induced hepatopathy. Especially in young patients with symptoms of hepatic damage frequent controls of clinical status and relevant laboratory parameters are of great importance. Patient transfer to a specialised centre should follow as early as possible; at the latest, when coagulopathy occurs.

Adolescent↗

PubMed2002

Combination prophylaxis with Hepatitis B immunoglobulin and lamivudine after liver transplantation minimizes HBV recurrence rates unless evolution of pretransplant lamivudine resistance.

BACKGROUND: Survival rates of hepatitis B patients after liver transplantation improved significantly by introduction of passive immunoprophylaxis. Due to viral escape mutations recurrence still occurs, but recently a combination prophylaxis with hepatitis B immunoglobuline plus lamivudine is evaluated in transplant centers in terms of a further reduction of recurrence rates. PATIENTS AND METHODS: Between 1996 and 2000 a postoperative combination prophylaxis with HBIg and lamivudine was initiated in 44 HBsAg positive liver transplant recipients. In total 14 patients were HBV-DNA negative and 30 were HBV-DNA positive at the time of evaluation. In 22 HBV-DNA positive patients a pre-operative lamivudine treatment (150 mg/die) was started. Five of them developed pre-transplant lamivudine resistance with high viral replication (mean HBV-DNA prior to transplantation 728 +/- 219 pg/ml). In all patients passive immunoprophylaxis was started in the anhepatic phase with application of 10.000 units hepatitis B immunoglobuline. It was continued after seroconversion to HBsAg negativity with an aimed titer of more than 100 U/l and only stopped in case of HBV recurrence. Lamivudine was also continued indefinitely after liver transplantation. RESULTS: Overall recurrence rate in the 44 patients, including retransplantations and patients with pretransplant lamivudine resistance, was 11.5 % under combination prophylaxis. Recurrence was seen only in one of 39 patients (2.6 %) without preoperative lamivudine resistance, in contrast 4 out of 5 patients (80 %) with pre-existing lamivudine resistance suffered from early hepatitis B recurrence. The single patient without preoperative lamivudine resistance, who developed recurrence was pre-transplant HBV-DNA negative without lamivudine treatment, but a postoperative seroconversion to negative HBsAg could not be achieved. The overall 3 year patient survival rate was 91 % in the study population. One patient, who was retransplanted with preoperative lamivudine resistance, died 4.5 months after retransplantation due to hepatitis B recurrence and sepsis, three other patients died for reasons not related to hepatitis B recurrence. Combination prophylaxis was well tolerated in all patients and no severe side effects were observed. CONCLUSION: Combination prophylaxis with hepatitis B immunoglobulin and lamivudine is safe and highly effective in prevention of HBV recurrence after liver transplantation, even in case of positive viral replication. In accordance with the results of other centers it should therefore be the standard regimen. However it fails in the majority of patients with preoperative evolution of YMDD mutations, in which the optimal management has to be determined yet. To minimize preoperative resistance formation universal preoperative antiviral treatment of HBV-DNA positive patients should be replaced by individualized indication for preoperative treatment.

Adult↗

PubMed2002

[Influence of probiotics and fibre on the incidence of bacterial infections following major abdominal surgery - results of a prospective trial].

INTRODUCTION: Early enteral nutrition with fibre and probiotics has been effective in preventing bacterial translocation and is therefore expected to reduce the incidence of postoperative bacterial infections. PATIENTS AND METHODS: In a prospective randomized trial including 172 patients following major abdominal surgery or liver transplantation, the incidence of bacterial infections was compared in patients receiving either a) conventional parenteral or enteral nutrition, b) enteral nutrition with fibre and lactobacillus plantarum 299 or c) enteral nutrition with fibre and heat inactivated lactobacilli (placebo). Liver transplant recipients were also treated with selective bowel decontamination (SBD). Routine laboratory parameters, nutritional parameters and the cellular immune status were measured preoperatively and on postoperative days 1, 5 and 10. RESULTS: Patients were comparable regarding preoperative ASA-classification, Child-Pugh classification of cirrhosis, operative data and immunosuppression. The incidence of bacterial infections after liver, gastric oder pancreas resection was 31 % in the conventional group a) compared to 4 % in the lactobacillus-group b) and 13 % in the placebo-group c). In the analysis of 95 liver transplant recipients, 13 % group b)-patients developed infections compared to 48 % group a)-patients and 34 % group c)-patients. The difference between groups a) and b) was statistically significant in both cases. In addition, the duration of antibiotic therapy was significantly shorter in the lactobacillus-group. Cholangitis and pneumonia were the most frequent infections and enterococci the most frequently isolated bacteria. Fibre and lactobacilli were well tolerated in most cases. CONCLUSION: Fibre and probiotics could lower the incidence of bacterial infections following major abdominal surgery in comparison to conventional nutrition with or without SBD. With this new concept, costs can be reduced by shortening the duration of antibiotic therapy and sparing SBD.

Adult↗

PubMed2002

[Orthotopic liver transplantation in case of TIPS stent dislocation].

Transjugular intrahepatic portosystemic shunts (TIPS) are indicated in patients with liver cirrhosis and portal hypertension for treatment of variceal bleeding or refractory ascites. Additionally implantation of stents may lead to stent dislocation or thrombosis in up to 20 % of cases. Detailed information about stent dislocation and its impact on subsequent orthotopic liver transplantation (OLT) is rare regarding the literature. We report on a patient suffering from ethyltoxic liver cirrhosis in which OLT was technically complicated by a thrombosed TIPS stent, dislocated in the portal vein. This stent was implanted prior to OLT due to refractory ascites and partial portal vein thrombosis. We conclude that TIPS stent insertion, especially in liver transplant candidates, should only be performed by radiologists in centers with expertise and experience.

Esophageal and Gastric Varices↗

PubMed2002

Phase I study of gemcitabine in combination with cisplatin, 5-fluorouracil and folinic acid in patients with advanced esophageal cancer.

The prognosis for advanced esophageal carcinoma is poor with a median survival of 9-12 months and 5-year-survival rate of 10-20%. Combination chemotherapy with cisplatin and 5-fluorouracil (5-FU) is considered to be the standard therapy, but has a high potential of side effects and is usually not given on an ambulatory basis. This phase I study was designed to find the maximum tolerated dose (MTD) of weekly cisplatin in combination with standard doses of gemcitabine (1,000 mg/m(2), 30 min) and 5-FU (750 mg/m(2), 24 h)/folinic acid (200 mg/m(2), 30 min). All drugs were to be given on a day 1, 8, 15 and 22 of a 6-weekly cycle in an outpatient setting. Nineteen chemonaive patients with inoperable stage IIa, III and IV squamous cell carcinoma and adenocarcinoma of the esophagus were enrolled into the study. Eight, six and five patients were enrolled at cisplatin dose levels 0 (20 mg/m(2) ), I (25 mg/m(2) ) and II (30 mg/m(2)), respectively. One hundred and eighty-one out of 187 treatments (55 cycles) were given on an outpatient basis. The dose-limiting toxicities of this schedule were leukopenia and thrombocytopenia. Other side effects were mild. Dose level II (30 mg/m(2)) was defined as the MTD for cisplatin when used in this combination and schedule. Partial responses were observed in 10 of the 19 enrolled patients. The side effect profile seen in this study in combination with the preliminary evidence of efficacy justifies further testing in a phase II setting with a cisplatin dose of 25 mg/m(2) and offers a treatment option for patients in an outpatient setting.

Adenocarcinoma↗

PubMed2002

A method to assess biochemical activity of liver cells during clinical application of extracorporeal hybrid liver support.

Biochemical activity of a hybrid liver support system based on porcine liver cells was investigated in patients suffering from acute liver failure, coma stage III-IV Patient plasma was drawn systemically and after circulation through the bioreactor at four hour intervals. A method is used that takes into account the rate of plasma flow and the differences in plasma concentration systemically and after circulation through the liver support system to determine the net release or uptake of metabolites such as ammonia, urea and glucose. Urea release (mean 2.28+/-0.37 micromol/h/g cells) and ammonia uptake (mean 0.17+/-0.11 micromol/h/g cells) was seen during treatment, an active role of the system in glucose metabolism was observed. All patients were bridged successfully to liver transplantation.

Ammonia↗

PubMed2002

Primary human liver cells as source for modular extracorporeal liver support--a preliminary report.

Cell-based extracorporeal liver support is an option to assist or replace the failing organ until regeneration or until transplantation can be performed. The use of porcine cells or tumor cell lines is controversial. Primary human liver cells, obtained from explanted organs found to be unsuitable for transplantation, are a desirable cell source as they perform human metabolism and regulation. The Modular Extracorporeal Liver Support (MELS) concept combines different extracorporeal therapy units, tailored to suit the individual and intra-individual clinical needs of the patient. A multi-compartment bioreactor (CellModule) is loaded with human liver cells obtained by 5-step collagenase liver perfusion. A cell mass of 400 g - 600 g enables the clinical application of a liver lobe equivalent hybrid organ. A detoxification module enables single pass albumin-dialysis via a standard high-flux dialysis filter, and continuous veno-venuous hemodiafiltration may be included if required. Cells from 54 human livers have been isolated (donor age: 56 +/- 13 years, liver weight: 1862 +/- 556 g resulting in a viability of 55.0 +/- 15.9%). These grafts were not suitable for LTx, due to steatosis (54%), cirrhosis (15%), fibrosis (9%), and other reasons (22%). Out of 36 prepared bioreactors, 10 were clinically used to treat 8 patients with liver failure. The overall treatment time was 7-144 hours. No adverse events were observed. Initial clinical applications of the bioreactor evidenced the technical feasibility and safety of the system.

Bioreactors↗

PubMed2002

Analysis of allogeneic versus xenogeneic auxiliary organ perfusion in liver failure reveals superior efficacy of human livers.

PURPOSE: To compare the efficacy of allogeneic and xenogeneic extracorporeal liver perfusion (ECLP). METHODS: An Internet-based keyword search was performed in the established online databases. Univariate and multivariate analysis of variance (general linear method) were performed. RESULTS: Data from 198 patients were included in the statistical analysis, 142 of whom were treated by ECLP using porcine livers. Baboon livers were used in 29 patients, human livers in 14, and other or mixed species in 13 patients. Pig liver perfusions resulted in a 20% long-term-survival whereas the use of human livers was significantly more successful (survival rate (SVR) 43%, p<0.05). Baboon livers also revealed superior success (41%; p<0.05). Twenty-three patients were treated after 1991, 12 surviving long-term (52%). The latter all belonged to a group of 14 patients who received combined treatment consisting of ECLP and LTx (SVR-86% in this subgroup). CONCLUSION: Allogeneic ECLP was accompanied by significantly improved outcome compared with discordant xenogeneic ECLP. The role of hyperacute rejection in acute liver failure with reduced complement levels remains controversial. Physiologic disparity between pig and man may be the even more decisive determinant of outcome.

Animals↗

PubMed2002

Extracorporeal liver support: porcine or human cell based systems?

Initial results of the clinical use of primary porcine liver cells for extracorporeal liver support are being reviewed as the cell source is controversial. According to Eurotransplant data 20-25% of explanted donor livers are not transplanted, due to factors such as steatosis or cirrhosis. This number corresponds to the number of patients with acute liver failure who require bridging therapy to transplantation. Primary human liver cells from transplant discards can be isolated, purified and maintained in bioreactors and provide an alternative for cell-based extracorporeal liver support therapy. A four-compartment bioreactor enables recovery from preservation and isolation injury in a three-dimensional network of interwoven capillary membranes with integrated oxygenation, rendering the liver cells from these discarded donor organs viable for clinical utilization. Patient contact with additional animal-derived biomatrix and fetal calf serum can be avoided. The initiation of an in vitro cultivation phase allows cell stabilization, quality control, and immediate availability of a characterized system without cryopreservation. The hypothesis of this paper is that with appropriate logistics and four-compartment bioreactor technology, cells from human liver transplant discards can serve the demand for cell-based therapy, including extracorporeal liver support.

Animals↗

PubMed2001

Transplantation of organs from marginal donors.

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Cause of Death↗