Biomedical subjects

Peter Neuhaus

Publications and source records attributed to Peter Neuhaus.

At least 109 records · Page 6Linked to original sources

PubMed2004

Induction, expression and maintenance of cytochrome P450 isoforms in long-term cultures of primary human hepatocytes.

Within the past decade, tremendous progress has been made in the isolation and culture of human hepatocytes for drug metabolism and toxicology, which could potentially reduce the number of animal experiments performed. However, human hepatocyte cultures are still not widely used for preclinical drug testing, partly due to inconsistent supply and quality of human tissue. Thus, the aim of this study was to evaluate primary cultured human hepatocytes from different patients over a study period of 14 days, by assays that characterise cell quality and function. We found urea production and albumin synthesis in all cell cultures over at least 7 days. Cytochrome P4501A2, CYP2D6, and CYP3A4 protein expression was demonstrated by Western Blot analysis and CYP1A1/2 and CYP3A4 induction by 3-methylcholantrene, phenobarbital or rifampicin over 14 days. In addition, we saw that UDP-glucoronyltransferase activity was preserved in human hepatocytes over 2 weeks. In conclusion, we could show that primary human hepatocytes isolated from discarded liver tissue can consistently be kept in culture over a long time period and are therefore well suited for preclinical drug testing.

Albumins↗

PubMed2004

Modifications of immune regulations with increasing donor & recipient age.

Increasing amounts of older recipients are listed for transplantation. Several clinical trials have therefore been initiated recently using age-adapted immunosuppressive regimens. Preliminary data in an "old-for-old" kidney transplant program at our center suggest that the approach favouring reduced immunosuppression in aged subjects might not be the best choice. We performed an experimental study to investigate the effects of donor and recipient age on renal allograft outcome and age associated alterations of the immune response. Modifications of the immune response in older recipients were associated with increased amounts of memory and alloreactive T-cells and an altered cytokine response. Recipient age dependent immune responses contributed to an acceleration of chronic graft deterioration, so that recipient age may need to be considered as a separate and independent risk factor. Although our experimental data need to be confirmed clinically, they suggest a modified and age-adapted immunosuppression in elderly recipients during the early posttransplant period.

Aged↗

PubMed2004

Brain death associated ischemia/reperfusion injury.

I/R is an important non-immunological, antigen independent factor influencing graft outcome. In addition to its non-specific effects it potentiates graft immunogenicity and increases host alloresponsiveness. Originally considered an event surrounding organ procurement, preservation and revascularization, it has recently been associated with donor conditions such as brain death and the non-heart-beating donor. Occurring early in the transplant process, it initiates a cascade of molecular and cellular events including the release of proinflammatory mediators and attraction of various cell types infiltrating the tissues. As a consequence, acute and chronic changes develop which influence structure and function of the organ which may contribute to reduced graft survival. Eventually, attentuation of I/R by strategies interfering with the different processes promoted by this insult may constitute a means to improve both short and long-term graft outcome.

Animals↗

PubMed2003

Alterations of the immune response with increasing recipient age are associated with reduced long-term organ graft function of rat kidney allografts.

BACKGROUND: Clinically, an increasing number of older recipients are listed for transplantation. We examined recipient age-associated alterations of the immune response and their effects on graft function. METHODS: Three- and 18-month-old Lewis (LEW) rats received kidneys from 3- and 18-month-old Fischer 344 (F344) rats (1.5 mg/kg/d cyclosporine A for 10 days; n=6/group) and were observed for 180 days. In additional groups, double kidney transplantations were performed to determine the impact of nephron mass and recipient age on graft outcome. RESULTS: All young recipients but only 66% of old recipients survived the observation period. Increasing recipient age resulted in a significant decrease in renal allograft function (P<0.001), more advanced morphologic evidence of chronic allograft damage (P<0.001), and greater cellular infiltration (P<0.05) and major histocompatibility complex expression (P<0.01) within grafts. Additional in vitro studies examined age-related changes in the cellular immune response by enzyme-linked immunosorbent assay, fluorescence-activated cell sorter analysis, and alloreactive enzyme-linked immunospot: splenocytes from old LEW rats produced significantly more interleukin (IL)-2 (P<0.0001), IL-4 (P<0.05), interferon (IFN)-gamma (P<0.0001), and tumor necrosis factor-alpha (P<0.05). IFN-gamma-producing memory-type T cells were significantly elevated in older rats (P<0.0001). Moreover, they revealed significantly more alloreactive T cells directed against F344 (146 +/- 64.2 and 512 +/- 277/10(6) T cells; P<0.05). Double renal allografts from young donors into old recipients confirmed an independent effect of recipient age on the acceleration of chronic graft deterioration. CONCLUSIONS: The enhanced cellular immune responsiveness in elderly recipients was associated with advanced chronic graft injury. Clinically, older recipients may need a modified immunosuppression.

Aging↗

PubMed2003

Parasite removal and its impact on litter size and body condition in Columbian ground squirrels (Spermophilus columbianus).

The current interest in studies of parasite-host relationships is focusing on the impact of parasites on mate choice, sexual selection and individual fitness. While most studies have been done on birds and fishes, little is known about the interactions between parasites and reproductive success in mammals. In this study, I experimentally removed ectoparasites (mainly fleas) from some female Columbian ground squirrels using a commercially available powder, whereas other squirrels were left untreated as controls. The anti-parasite treatment led to an increase in female body condition during lactation and at weaning and an increase in litter size. The increase of body mass in treated females between birth of the young and weaning is also different from observations done over 8 years in the same population, where untreated females usually lost mass. In close to 400 litters from untreated females in the same area, only 2% had litter sizes as big as the treated females. I conclude that ectoparasites can have a profound impact not only on individuals but probably on the dynamics of the whole population.

Alberta↗

PubMed2003

Use of primary human liver cells originating from discarded grafts in a bioreactor for liver support therapy and the prospects of culturing adult liver stem cells in bioreactors: a morphologic study.

INTRODUCTION: The development of a bioreactor providing a three-dimensional network of interwoven capillary membranes with integrated oxygenation and decentralized mass exchange enables the culture of primary human liver cells from discarded donor organs for extracorporeal liver support. METHODS: Primary liver cells were isolated from 54 discarded organs (donor age 56.7+/-13.2 years). Between 2.8x10(10) and 6.4x10(10) parenchymal cells (PC) were cocultured with nonparenchymal cells (NPC) of the same organ in bioreactors (n=36). The metabolic activity of the cells was regularly determined during culture. The cell morphology and ultrastructure were investigated after culture periods of 1 to 5 weeks. RESULTS: Cell metabolism was maintained over at least 3 weeks after a phase of adaptation lasting 2 to 3 days. Through the use of transmission electron microscopy and immunohistochemistry, it was demonstrated that PC and NPC spontaneously formed tissue-like structures. Vascular cavities (CD 31 immunoreactivity [IR]) and bile duct-like channels (CK 19 IR), both exhibiting proliferation activity (Ki-67 IR), were regularly distributed. Some of the bile duct-like channels showed similarities to the Canals of Hering found in the natural liver. Cells expressing morphologic and antigenic characteristics of adult liver stem cells (CD 34 IR and c-kit IR) and areas with cells that showed both hepatocyte and biliary characteristics were detected. CONCLUSION: The results show that primary human liver cells obtained from discarded donor organs recover and can be maintained in bioreactors for clinical liver support therapy. In addition, initial observations on adult liver stem-cell culture in bioreactors are presented.

Aged↗

PubMed2003

Correlation between angiographic runoff and intraoperative hydraulic impedance with regard to graft patency.

The aim of this study was to evaluate the correlation between peripheral runoff estimated by the SVS/ISCVS scoring system and intraoperatively measured outflow. Sixty-six patients received 27 femoropopliteal and 39 femorocrural ePTFE grafts. During the operation, peripheral resistance and hydraulic impedance were measured by means of the extracorporeal-bypass-flow method. Angiographic runoff was estimated according to the revised SVS/ISCVS system. Patients were entered in a graft surveillance program and patency was calculated after 3 years. The relation between the angiographic runoff score and graft patency as well as correlations between hemodynamic data, peripheral resistance, and hydraulic impedance were calculated. Primary and secondary patency rates for femoropopliteal grafts were 44% and 60% and those for femorocrural bypasses were 35% and 45%. Mean angiographic vessel diameters for above-knee and below-knee popliteal arteries were 0.51 +/- 0.02 mm and 0.47 +/- 0.04 mm. Diameters of crural arteries were 0.34 +/- 0.03 mm (posterior tibial artery), 0.27 +/- 0.02 mm (anterior tibial artery) and 0.26 +/- 0.21 mm (peroneal artery). The differences in diameter between popliteal and crural grafts were statistically significant ( p < 0.01). Calculated correlations between the preoperative score and hemodynamic, resistance, and impedance values or patency rates were generally poor and statistically not significant. A statistical significant correlation was found only between SVS/ISCVS score and recipient vessel diameters. The angiographic runoff did not correlate with peripheral resistance, impedance, or patency rates. Patients with angiographically poor outflow should additionally be evaluated with duplex sonography or magnetic resonance angiography and should not be denied peripheral reconstructions.

Adult↗

PubMed2003

Successful infliximab treatment of steroid and OKT3 refractory acute cellular rejection in two patients after intestinal transplantation.

Acute rejection resistant to established immunosuppressive rescue protocols remains the most prominent risk factor after intestinal transplantation. In two patients presenting with steroid-resistant severe acute cellular rejection 9 months and 2 years after intestinal transplantation, complete resolution was not achieved despite 5 and 10 days of OKT3 treatment, respectively, and high-dose triple baseline immunosuppression with tacrolimus, rapamycin, and steroids. There was a dissociated course of rejection with persistent moderate to severe rejection in the terminal portion of the graft despite complete recovery from rejection in the proximal parts. Both patients were treated with four subsequent infusions of infliximab (3 mg/kg body weight), a chimeric anti-tumor necrosis factor-alpha antibody. There was an immediate response regarding macroscopic appearance, graft histology, and clinical symptoms. Both patients recovered. In conclusion, infliximab has proven to be an effective rescue therapy in a selected group of patients with steroid and OKT3 refractory severe acute rejection after intestinal transplantation.

Acute Disease↗

PubMed2003

Mycophenolatemofetil for immunosuppression after liver transplantation: a follow-up study of 191 patients.

BACKGROUND: Mycophenolatemofetil (MMF) combined with calcineurin inhibitors (CNIs) as immunosuppression after orthotopic liver transplantation (OLT) is still under discussion. We retrospectively investigated the immunosuppressive potency of MMF for treatment of steroid-resistant acute rejection (AR) or chronic rejection (CR), chronic graft dysfunction, and CNI-induced toxicity in patients after OLT. METHODS: Between 1988 and 2001 we performed 1386 OLTs in 1258 patients. Since 1995, 191 patients have received MMF after OLT for steroid-resistant AR or CR, chronic graft dysfunction (115 patients), and CNI-induced toxicity (76 patients). The mean follow-up time was 56 months. RESULTS: Of 47 patients with steroid-resistant AR, 12 had been treated with OKT3, without resolving the rejection. Overall, bilirubin and transaminases decreased significantly within 2 weeks after the addition of MMF, and liver function normalized in 38 patients. Five of eight patients with CR demonstrated stable liver function after a follow-up of 55+/-8 months; 52 of 60 patients with chronic graft dysfunction improved within 3 months; and 46 of 59 patients with CNI-induced nephrotoxicity improved after MMF treatment and a reduction of CNIs (with a significant decrease in serum creatinine within 2 weeks and an increase of creatinine clearance within 3 months). Clinical symptoms improved in 10 of 12 patients with neurotoxicity and four of five patients with hepatotoxicity. Side effects of MMF, such as gastrointestinal disorders or bone marrow toxicity, occurred in 60 patients (31.4%). The incidence of infections did not increase. Patient survival was 93%, and graft survival was 88.2%. CONCLUSIONS: MMF is a potent and safe immunosuppressive agent in OLT recipients for rescue therapy in AR, CR, or chronic graft dysfunction and helps to reduce the serious toxic side effects of CNIs.

Adult↗

PubMed2003

A survival-based scoring-system for initial graft function following orthotopic liver transplantation.

Initial graft function following orthotopic liver transplantation is a major determinant of postoperative survival and morbidity. Despite several efforts to provide scoring-systems for initial graft function, there is still a lack of a generally accepted classification scheme. The previously published systems assessed initial graft function based on the first postoperative days or weeks using liver-related laboratory parameters. It was shown that in most cases the scoring-systems did not correlate with patient survival. We intended to refine the definition of initial graft function in order to provide a survival based classification system. In a retrospective analysis of 761 patients following primary liver transplantation, a new scoring-system for early postoperative graft function was developed. Statistically significant differences in long term survival were calculated for ALAT, ASAT, bile production and prothrombin activity on days 1, 3, 7, 14. Points were then assigned according to the degree of survival: improved survival=1 point, poor survival=2 points. Patients were split into three groups corresponding to initially good, moderate and poor function. Applying this score, early and late patient survival rates and incidence of initial non-function were statistically significantly different. This was in contrast to the Gonzalez and the Ploeg-Maring classification scales, which are based on arbitrarily chosen cutoff levels. Retransplantation rates and postoperative morbidity were comparable both for the new and the older systems. We can conclude that the presented refined scoring-system for initial graft function provides a significant correlation to patient survival and initial non-function. We recommend the refined system for future studies.

Adult↗

PubMed2003

Complex vascular reconstructions in living donor liver transplantation.

We describe here the indications for and our experience with complex vascular reconstructions in living donor liver transplantation. From December 1999 to June 2002, 59 patients underwent liver transplantation, 51 receiving the right lobe, and 8 the left lateral lobe, as a graft from a living donor. The indication for interpositional grafts on the arterial side (6/59, 10%) were stenoses of the celiac trunk and after resection of the hepatic artery for oncological reasons in adults. In children, arterial interpositional grafts were performed in situations of long distances between the donor and recipient artery, or in cases of inflow release from the aorta in patients with small hepatic arteries. On the portal-venous side, one interpositional graft was performed after an oncological resection. Once the portal vein was partially arterialized because of insufficient inflow. We used veins from the recipient, and native or cryopreserved arterial homografts for these grafts. All patients were treated during the first 6 months after transplantation with aspirin only. During the follow-up we did not observe vascular complications. If required, vascular interpositional grafts in the arterial and portal-venous position can be performed without adding postoperative complications.

Anastomosis, Surgical↗

PubMed2003

Surgical management of proximal bile duct cancer: extended right lobe resection increases resectability and radicality.

BACKGROUND: Surgical resection provides the only chance of cure for patients suffering from hilar cholangiocarcinoma. Although appropriate procedures are not agreed upon, an increase in radicality has been observed during the past 20 years. METHODS: The literature as well as our own experience after 133 resections of hilar cholangiocarcinomas were reviewed. RESULTS: Tumor-free margins represent the most important prognostic parameter. Hilar resections as least radical resective procedure will generate rates of formally curative resections of less than 50%. Even after these formally curative resections, long-term survival cannot be achieved. Only additional liver resections will increase the number of long-term survivors to significant figures. In our series, the best 5-year survival rate of 72% was achieved after right trisegmentectomy with concomitant resection of the portal vein bifurcation. CONCLUSION: Right trisegmentectomy and combined portal vein resection represent the best way to comply with basic rules of surgical oncology for hilar cholangiocarcinoma. This procedure will provide the most pronounced benefit among various types of liver resection, whereas local resections of the extrahepatic bile duct must be considered as an oncologically inefficient procedure.

Bile Duct Neoplasms↗

PubMed2003

Short-term immunosuppressive treatment of the donor ameliorates consequences of ischemia/ reperfusion injury and long-term graft function in renal allografts from older donors.

BACKGROUND: Grafts from so-called "marginal donors" are increasingly used for organ transplantation. The combination of reduced organ quality and additional inflammatory damages may be particularly detrimental in these grafts. In a previous study, we showed the beneficial effects on long-term graft outcome of "suboptimal" grafts by the induction of heme oxygenase-1. Here we tested the impact of short-term donor treatment with established immunosuppressants. METHODS: Twelve-month-old Fischer 344 donor rats either were treated with prednisolone, mycophenolate mofetil, RAD, or FK506 24 hr and 1 hr before organ harvesting or remained untreated. Renal allografts were perfused with University of Wisconsin solution and kept at 4 degrees C for an ischemic period of 2 hr. Morphologic, immunohistologic, and real time reverse transcriptase-polymerase chain reaction analyses for relevant markers were performed at serial intervals and at the end of the observation period (6 months). RESULTS: All animals survived the observation period, although the ischemic time resulted in accelerated chronic graft dysfunction. Grafts from donors treated with prednisolone or FK506 demonstrated significantly improved graft function and structure by 6 months. Mononuclear infiltrates were significantly reduced by the end of the observation period, whereas intragraft mRNA levels of tumor necrosis factor-alpha and interleukin-10 were significantly altered during the early period after transplantation. Minor improvements in graft function and histologic alterations of suboptimal grafts were observed after pretreatment with mycophenolate mofetil and RAD. CONCLUSION: Donor treatment with approved immunosuppressants, in particular prednisolone or FK506, represents a novel therapeutic strategy of clinical relevance, most importantly when using grafts from marginal donors.

Age Factors↗

PubMed2003

Primary permanent arterialization of the portal vein in liver transplantation.

Permanent total arterialization of the portal vein in liver transplantation has been described as a method of providing portal inflow after insufficient thrombectomy due to chronic occlusion of the portal-vein system. A specific problem is the restriction of the arterial inflow and its long-term adaptation after transplantation. We describe here the surgical techniques and clinical course of three patients who underwent portal-vein arterialization for liver transplantation. Two patients had an uneventful course. In one patient, a flow reduction by means of coil embolization of one arterial inflow branch was performed; thereafter, the patient recuperated well. Analysing the microcirculation of an arterialized graft in comparison with liver grafts with normal non-arterialized portal-vein inflow, we observed an increase in inter-sinusoidal distance and a decrease in sinusoidal red blood cell velocity. From a technical point of view, we recommend permanent portal-vein arterialization by an iliac artery graft interposition from the subdiaphragmatic aorta. The inflow to the portal vein can easily be reduced by the banding of the arterial graft interposition.

Adult↗

PubMed2003

Transforming growth factor beta 1 stimulates vascular endothelial growth factor gene transcription in human cholangiocellular carcinoma cells.

The expression pattern and functional interaction of proangiogenic factors in human cholangiocellular carcinoma (CCC) have not been fully defined. We therefore investigated the expression of vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta 1 as well as their respective receptors in human CCC tumor samples and further analyzed their functional interaction in vitro. Expression of VEGF, TGF-beta 1, and their receptors was examined by immunohistochemistry, in situ hybridization, quantitative competitive reverse transcription-PCR, and ELISA. VEGF promoter analysis and identification of transcription factors involved in promoter regulation were investigated using transient transfection and electrophoretic mobility shift assays. We observed strong expression of VEGF in CCC tumor cells and localization of VEGF receptors 1 and 2 in endothelial cells; in addition, coexpression of TGF-beta 1 and its receptors in tumor cells suggests a possible functional interaction between both cytokines. In vitro studies confirmed a paracrine/autocrine stimulation of VEGF by TGF-beta 1 at a transcriptional level. Additional molecular studies using 5' deletion and mutational analysis of the human VEGF promoter revealed that TGF-beta 1 stimulates VEGF through Sp1-dependent transcriptional activation. These data suggest that overexpression and functional interaction of TGF-beta 1 and VEGF might contribute to the "angiogenic switch" and the malignant phenotype in human CCC.

Bile Duct Neoplasms↗

PubMed2003

Quantitation of cytomegalovirus (hCMV) DNA and beta-actin DNA by duplex real-time fluorescence PCR in solid organ (liver) transplant recipients.

Even now rare human cytomegalovirus (hCMV) reactivation is still a life-threatening complication after solid organ transplantation. Although PCR techniques are regarded as the most sensitive detection methods for hCMV, their accuracy and reproducibility are limited. This is a major disadvantage with quantitative PCR assays, which are thought to provide valuable information about hCMV latency or active viral replication in transplant patients. To enhance the diagnostic safety of quantitative hCMV PCR, we developed a duplex real-time fluorescence PCR that is capable of quantifying hCMV DNA and beta-actin DNA as internal control simultaneously within one reaction. By the use of 6-carboxyfluorescein and hexa-chloro-6-carboxyfluorescein as reporter fluorophores and 4-(4'-dimethylamino-phenylazo) benzoic acid as dark quencher dye, hCMV DNA and beta-actin DNA could be quantified in parallel in a wide linear range from 10(1) to 10(7) copies, each. To test the clinical applicability of this approach, we investigated hCMV DNA kinetics in peripheral leukocytes of three hCMV antigen-positive and four antigen-negative patients after liver transplantation, as assessed by intracellular hCMV pp65 alkaline phosphate-anti-alkaline phosphate (APAAP) complex. While all APAAP-negative individuals remained PCR negative, kinetics of HCMV DNA in leukocyte DNA samples of APAAP-positive patients correlated closely with hCMV antigen tests. Here, comparison of separate and simultaneous target quantitation revealed identical results. It is of interest that, while single hCMV antigen positivity is commonly not regarded as a reliable parameter of viral reactivation, in our study a viral load greater than 10(4) copies/2x10(5) beta-actin DNA copies clearly indicated a subsequent increase in APAAP-positive leukocytes. We conclude that with the presented method the reliability of hCMV quantitation via real-time PCR can be substantially increased and may be used to monitor hCMV kinetics in vivo.

Actins↗

PubMed2003

Impact of human leukocyte antigen matching in liver transplantation.

BACKGROUND: Human leukocyte antigen (HLA) compatibilities are beneficial in the setting of kidney transplantation but have demonstrated inconclusive results after liver transplantation. On the basis of recent controversial reports, the authors analyzed the impact of HLA matching in their patients after liver transplantation under modern immunosuppressive drug regimens and new HLA typing techniques with respect to outcome and adverse immunologic events. METHODS: Data from 924 transplants with complete donor-recipient HLA typing were retrospectively analyzed. Immunosuppression was commenced as either cyclosporine A- or tacrolimus-based therapy in different protocols. The follow-up period ranged from 1 to 144.8 months (median, 66 months). RESULTS: The actuarial graft survival was 88% after 1 year and 78.7% after 5 years and was similar in tacrolimus- and cyclosporine A-treated patients. However, cyclosporine A-treated patients underwent significantly more rejection episodes. The number of HLA compatibilities had no influence on graft survival, whereas the number of acute rejections was significantly less in transplants with more HLA compatibilities (P<0.05). Graft survival tended to be improved in patients with chronic hepatitis B and more HLA compatibilities (P=0.05). In contrast, graft survival in transplants for primary sclerosing cholangitis was significantly impaired in the presence of one or two HLA-DR compatibilities (P<0.05). In addition, in autoimmune hepatitis, survival tended to be lower in the presence of more HLA compatibilities (P=0.1). Overall graft survival or frequency of adverse immunologic events was not influenced by any specific donor-recipient HLA allele. CONCLUSION: This study demonstrated fewer acute rejections in transplants with more HLA compatibilities. However, in liver transplantation, a more specific investigation of HLA typing may be necessary, because in some indications HLA antigens play a role in the nature of the disease. Therefore, recurrence of autoimmune disease may be more severe in patients sharing HLA antigens.

Adolescent↗

PubMed2003

Intrahepatic cholangiocarcinoma: indication for transplantation.

BACKGROUND/PURPOSE: Cholangiocarcinoma (CCC) is a rare malignant tumor of the biliary system with a poor prognosis that frequently presents in advanced unresectable stages. A discussion of the role of liver transplantation (LTx) for intrahepatic (IH)-CCC will be presented, based on a review of the international literature. METHODS: A search of the international literature related to the topic was performed in the established online databases and databanks. Only those reports with patient series larger than ten were included. RESULTS: The largest series of patients with IH-CCC ( n = 186) was reported in the Data Analysis Booklet of the European Liver Transplant Registry (ELTR), revealing 1-, 3-, 5-, 8-, and 10-year survival rates of 58%, 38%, 29%, 23%, and 21%. Other single-center series had comparable or even worse outcomes. More recent experience identified a certain highly selected group of patients who could benefit from LTx in an otherwise unresectable state of disease. Several single-center studies found tumor stage or size, lymph node involvement, and positive surgical margins/contiguous organ infiltration to be predictors of outcome. The recently published Mayo Clinic protocol uses preoperative chemoirradiation and staging at laparotomy before proceeding to liver transplantation, resulting in an early experience with 100% 1-year survival. CONCLUSIONS: Generally speaking, IH-CCC is not a favorable indication for liver transplantation. However, there is a highly selected group of patients with early tumor stages potentially benefitting from LTx. Combination with neoadjuvant chemoirradiation may further improve results after LTx. Living-donation LTx may open new therapeutic possibilities to treat patients at an early stage of disease.

Bile Duct Neoplasms↗