What is the best fruit juice to use as a negative oral contrast agent in magnetic resonance cholangiopancreatography?

AIM: To identify, in vitro, the best fruit juice to use as oral contrast agent in magnetic resonance cholangiopancreatography (MRCP) and to test, in vivo, the best natural juice and the new parameters in MRCP sequences identified in vitro. MATERIALS AND METHODS: The in vitro evaluations consisted of measuring the T2 values of a pure solution of manganese (Mn) and iron (Fe) at different concentrations, measuring the content of Mn and Fe in five commercial juices and their T2 relaxation times, and identifying the optimal juice dilution for suppressing the gastrointestinal fluid signal. The new parameters of MRCP sequences were tested in vivo. RESULTS: Manganese alone strongly influenced the shortening of the T2 values (p=0.004). The T2 value with an echo time (TE) of ≥1,000 ms enabled sufficient intestinal fluid suppression in the case of high juice dilution. A flip angle of 90° maximised the differences between the high signal from static fluids, such as the bile and the fluid in the gastrointestinal tract, using fast imaging employing steady-state acquisition (FIESTA) sequences (p<0.001). CONCLUSION: The shortening of the T2 relaxation time depended only on the Mn concentration. All the commercial juices had an Mn concentration sufficient to suppress the gastrointestinal fluid signal using long TE sequences. The oral ingestion of commercial juice before MRCP was enough to suppress the signal from the gastrointestinal fluids, regardless of its dilution after ingestion. When using FIESTA sequences, a flip angle of 90° allowed the best suppression of gastrointestinal fluid signals.

A new approach to the use of α-fetoprotein as surveillance test for hepatocellular carcinoma in patients with cirrhosis.

BACKGROUND: Surveillance for hepatocellular carcinoma (HCC) is recommended in patients with cirrhosis. As α-fetoprotein (AFP) is considered a poor surveillance test, we tested the performance of its changes over time. METHODS: Eighty patients were diagnosed with HCC (cases) during semiannual surveillance with ultrasonography and AFP measurement were recruited and matched for age, gender, etiology and Child-Pugh class with 160 contemporary cancer-free controls undergoing the same surveillance training group (TG). As a validation group (VG) we considered 36 subsequent patients diagnosed with HCC, matched 1 : 3 with contemporary cancer-free controls. α-Fetoprotein values at the time of HCC diagnosis (T0) and its changes over the 12 (Δ12) and 6 months (Δ6) before cancer detection were considered. RESULTS: In both TG and VG, >80% of HCCs were found at an early stage. In TG, AFP significantly increased over time only in cases. T0 AFP and a positive Δ6 were independently associated with HCC diagnosis (odds ratio: 1.031 and 2.402, respectively). The area under the curve of T0 AFP was 0.76 and its best cutoff (BC) was 10 ng ml(-1) (sensitivity 66.3%, specificity 80.6%). The combination of AFP >10 ng ml(-1) or a positive Δ6 composite α-fetoprotein index (CAI) increased the sensitivity to 80% with a negative predictive value (NPV) of 86.2%. Negative predictive value rose to 99%, considering a cancer prevalence of 3%. In the VG, the AFP-BC was again 10 ng ml(-1) (sensitivity 66.7%, specificity 88.9%), and CAI sensitivity was 80.6% with a NPV value of 90.5%. CONCLUSIONS: CAI achieves adequate sensitivity and NPV as a surveillance test for the early detection of HCC in cirrhosis.

Chip-based amperometric enzyme sensor system for monitoring of bioprocesses by flow-injection analysis.

A microfluidic chip integrating amperometric enzyme sensors for the detection of glucose, glutamate and glutamine in cell-culture fermentation processes has been developed. The enzymes glucose oxidase, glutamate oxidase and glutaminase were immobilized by means of cross-linking with glutaraldehyde on platinum thin-film electrodes integrated within a microfluidic channel. The biosensor chip was coupled to a flow-injection analysis system for electrochemical characterization of the sensors. The sensors have been characterized in terms of sensitivity, linear working range and detection limit. The sensitivity evaluated from the respective peak areas was 1.47, 3.68 and 0.28 µAs/mM for the glucose, glutamate and glutamine sensor, respectively. The calibration curves were linear up to a concentration of 20 mM glucose and glutamine and up to 10 mM for glutamate. The lower detection limit amounted to be 0.05 mM for the glucose and glutamate sensor, respectively, and 0.1 mM for the glutamine sensor. Experiments in cell-culture medium have demonstrated a good correlation between the glutamate, glutamine and glucose concentrations measured with the chip-based biosensors in a differential-mode and the commercially available instrumentation. The obtained results demonstrate the feasibility of the realized microfluidic biosensor chip for monitoring of bioprocesses.

Allocation priority in non-urgent liver transplantation: An overview of proposed scoring systems.

Given the lack of donors, a correct organ allocation system for candidates to liver transplantation is essential to increase graft and patient survival. The most used organ allocation tools are Child-Turcotte-Pugh and model for end-stage liver disease. It is generally accepted that model for end-stage liver disease score is superior to the Child-Turcotte-Pugh classification in predicting the short-term survival of cirrhotic patients awaiting liver transplantation. Since 2002, model for end-stage liver disease is widely used for liver allocation. In recent years, to overcome limitations of the consolidated scores, some adjustments to the original model for end-stage liver disease formula and new scoring systems have been proposed. Published data suggest that integrating serum sodium and model for end-stage liver disease may improve the score prognostic accuracy but further studies are necessary to confirm this issue. The updated model for end-stage liver disease, obtained through a revision of traditional model for end-stage liver disease parameters and tested in a large cohort of patients, is of great interest at the moment. In conclusion, several scoring systems have been described for organ allocation, but today, none is definitely able to overcome the limitations of the Child-Turcotte-Pugh and model for end-stage liver disease systems.

Clinical trial: peg-interferon alfa-2b and ribavirin for the treatment of genotype-1 hepatitis C recurrence after liver transplantation.

BACKGROUND: Treatment of hepatitis C virus (HCV) recurrence after liver transplantation (LT) is difficult with low response rates. AIM: To assess the safety and efficacy of pegylated-interferon (PEG-IFN) alfa-2b + ribavirin (RBV) in patients with post-LT recurrent genotype-1 HCV and to establish stopping rules according to response. METHODS: Fifty-three patients with post-LT HCV recurrence were enrolled. Patients received PEG-IFN alfa-2b 1.0 micro/kg/week plus RBV 8-10 mg/kg/day for 24 weeks. Those with 'early virological response at week 24' (EVR24) continued treatment for 24 weeks (group A). Patients without EVR24 were randomized to continue (group B) or to discontinue (group C). RESULTS: Overall sustained virological response (SVR) was 26% (14/53). Alanine aminotransferase, rapid virological response, EVR12, EVR24, undetectable serum HCV-RNA at weeks 12 (cEVR12) and 24 (cEVR24) were related to SVR. cEVR12 and cEVR24 (OR: 14.7; 95% CI: 2.02-106.4) were independent predictors of SVR. All patients with SVR, had cEVR12. No patient in groups B and C achieved end-of-treatment response. One patient in group B had SVR. CONCLUSIONS: Pegylated-interferon alfa-2b was effective in one of four of patients with HCV genotype 1 after LT. Treatment should be discontinued in patients with no virological response at week 12. Further studies are needed to evaluate whether a longer treatment period may be beneficial in patients with > or =2 log10 drop in HCV-RNA at week 24.

High incidence of allograft dysfunction in liver transplanted patients treated with pegylated-interferon alpha-2b and ribavirin for hepatitis C recurrence: possible de novo autoimmune hepatitis?

BACKGROUND: Interferon may trigger autoimmune disorders, including autoimmune hepatitis, in immunocompetent patients. To date, no such disorders have been described in liver transplanted patients. METHODS: 9 of 44 liver transplanted patients who had been receiving pegylated-interferon alpha-2b and ribavirin for at least 6 months for hepatitis C virus (HCV) recurrence, developed graft dysfunction despite on-treatment HCV-RNA clearance in all but one case. Laboratory, microbiological, imaging and histological evaluations were performed to identify the origin of graft dysfunction. The International Autoimmune Hepatitis scoring system was also applied. RESULTS: In all cases infections, anastomoses complications and rejection were excluded, whereas the autoimmune hepatitis score suggested a "probable autoimmune hepatitis" (score from 10 to 14). Three patients developed other definite autoimmune disorders (overlap anti-mitochondrial antibodies (AMA)-positive cholangitis, autoimmune thyroiditis and systemic lupus erythematosus, respectively). In all cases, pre-existing autoimmune hepatitis was excluded. Anti-lymphocyte antibodies in immunosuppressive induction treatment correlated with the development of the disorder, whereas the use of granulocyte colony-stimulating factor to treat interferon-induced neutropenia showed a protective role. Withdrawal of antiviral treatment and treatment with prednisone resulted in different outcomes (five remissions and four graft failures with two deaths). CONCLUSIONS: De novo autoimmune hepatitis should be considered in differential diagnosis along with rejection in liver transplanted patients developing graft dysfunction while on treatment with interferon.

Review article: alcoholic liver disease--pathophysiological aspects and risk factors.

BACKGROUND: Alcoholic liver disease has a known aetiology but a complex and incompletely known pathogenesis. It is an extremely common disease with significant morbidity and mortality, but the reason why only a relatively small proportion of heavy drinkers progress to advanced disease remains elusive. AIM: To recognize the factors responsible for the development and progression of alcoholic liver disease, in the light of current knowledge on this matter. METHODS: We performed a structured literature review identifying studies focusing on the complex pathogenetic pathway and risk factors of alcoholic liver disease. Results In addition to the cumulative amount of alcohol intake and alcohol consumption patterns, factors such as gender and ethnicity, genetic background, nutritional factors, energy metabolism abnormalities, oxidative stress, immunological mechanisms and hepatic co-morbid conditions play a key role in the genesis and progression of alcoholic liver injury. CONCLUSIONS: Understanding the pathogenesis and risk factors of alcoholic liver disease should provide insight into the development of therapeutic strategies.

Pegylated interferon plus ribavirin for recurrent Hepatitis C infection after liver transplantation in naïve and non-responder patients on a stable immunosuppressive regimen.

BACKGROUND: Hepatitis C virus recurrence after liver transplantation is universal, leading to chronic hepatitis and cirrhosis. AIMS AND PATIENTS: We evaluated the efficacy and safety of pegylated interferon and ribavirin in 20 patients with recurrent Hepatitis C virus after liver transplantation (10 naïve and 10 non-responders to a previous interferon course). METHODS: Treatment consisted of pegylated interferon alfa-2b (1.0 microg/kg once weekly) and ribavirin (600 mg/daily) for at least 6 months. Therapy continued for an additional 6 months only in patients with undetectable serum Hepatitis C virus-RNA or >2 log drop from baseline levels. RESULTS: Eleven out of 20 patients (55%) completed 1 year of treatment. Nine patients (45%) had undetectable Hepatitis C virus-RNA at the end of treatment, six of them were naïves and three non-responders. In all of them, virological response persisted 6 months after discontinuation of therapy, so the sustained virological response rate was 60% in naïve patients and 30% in non-responders. CONCLUSIONS: Our results suggest that pegylated interferon plus ribavirin combination therapy may be effective in patients with post-liver transplantation recurrent chronic Hepatitis C, even in those previously non-responders to interferon plus ribavirin. These results need to be confirmed by large studies.

Cytokine profile of peripheral blood mononuclear cells from patients with different outcomes of hepatitis C virus infection.

SUMMARY: The relationship between the balance of helper T-cell type 1 (Th1) or type 2 (Th2) cytokines and the clinical course of hepatitis C virus (HCV) infection is unclear. We evaluated Th1 [interleukin (IL)-2, interferon-gamma (IFN-gamma)] and Th2 cytokine (IL-4, IL-10) and 2,5-oligoadenylate synthetase (OAS, an IFN-induced antiviral protein) production by peripheral blood mononuclear cells from 10 healthy anti-HCV-positive individuals (group A), 10 HCV-RNA-positive with persistently normal alanine aminotransferase (ALT) levels (group B), 10 HCV-RNA-positive with abnormal ALT (group C) and 10 uninfected healthy controls. IL-2 production was significantly increased in group B when compared with all the other groups. No difference was found for IFN-gamma. IL-4 was significantly higher in group C than in both group B (P = 0.0006) and controls (P = 0.004). Compared with controls, IL-10 was significantly decreased in group A (P = 0.013) and B (P = 0.004). The production of 2,5-OAS was significantly higher in group B than in A (P = 0.04) and in C (P = 0.004). Finally, in all HCV-RNA-positive patients, a significant correlation was found between ALT and both IL-2 (r = -0.78; P = 0.0008) and IL-4 (r = 0.75; P = 0.0008). IN CONCLUSION: (i) subjects who cleared HCV showed a cytokine profile similar to controls; (ii) a preferential shift towards a Th1 profile seems associated with a more favourable clinical outcome in chronic hepatitis C; and (iii) a prevalent Th2 profile seems implicated in HCV pathogenesis and severity of liver disease.

High risk of hepatocellular carcinoma in anti-HBe positive liver cirrhosis patients developing lamivudine resistance.

The emergence of drug-resistant virus in hepatitis B virus patients treated with lamivudine is well documented. However, its clinical impact in the long-term treatment of anti-HBe positive compensated cirrhotic patients is not well known. In this study, we treated 22 consecutive patients with anti-HBe compensated cirrhosis with lamivudine for a median period of 42 months. All patients responded to lamivudine, but viral breakthrough occurred in 13 patients (59%) between 9 and 42 months of therapy due to the emergence of a mutant strain. During the follow-up, 11 developed hepatocellular carcinoma. Of these, 10 occurred soon after the emergence of viral resistance, generally showing aggressive behaviour, and one in the nine long-term responder patients (P = 0.013). Lamivudine resistance was the only independent predictor of hepatocellular carcinoma development (risk ratio: 10.4; 95% CI: 1.3-84.9). Our study suggests that the occurrence of lamivudine resistance increases the risk of hepatocellular carcinoma in anti-HBe positive cirrhosis and warrants further research.

Thymosin-alpha 1 plus interferon-alpha for naive patients with chronic hepatitis C: results of a randomized controlled pilot trial.

In this pilot study, we evaluated the efficacy of interferon-alpha (IFN) plus Thymosin-alpha 1 (TA1) to that of IFN alone in naive patients with chronic hepatitis C. Twenty-two patients were randomized to receive interferon-alpha 2b (3 million units three times a week) plus thymosin-alpha l (900 microg/m2 body surface area) and 19 received interferon-alpha 2b alone at the same dose. Patients were treated for 6 months and followed up for another 6 months. Biochemical (alanine aminotransferase values) and virological (hepatitis C virus-RNA) responses to treatment were determined. Combination treatment showed significantly higher efficacy than monotherapy in achieving virological end-of-treatment response (P = 0.03). At 6-month follow up, the sustained biochemical and virological response was not different between the two groups. Our results indicate that the immune modulator TA1 may enhance the end-of-treatment response in naive patients with chronic hepatitis C. Higher doses and/ore more prolonged courses as well as the association with new interferon formulation such as pegylated interferons could improve the sustained response rates to this treatment.

Biological and mechanical quality of red blood cells cultured from human umbilical cord blood stem cells.

Human umbilical cord blood (CB) has moved from the status of biological waste to that of a valuable source of haematopoietic stem (HS) cells. There are potentially three major clinical applications for HS cells and ex vivo-expanded HS cells: reconstitution of haematopoiesis in patients undergoing chemotherapy; gene therapy (e.g. in thalassaemia, sickle cell anaemia); and large-scale production of mature blood cells. Erythropoiesis is accomplished by highly complex interactions of haematopoietic progenitor cells, stromal cells and cytokines in the bone marrow. Among them, erythropoietin is the principal regulator. Ex vivo cell culture experiments to obtain mature red blood cells were the focus of this study. Attempts to elucidate appropriate medium components and amounts of haematopoietic growth factors were successful: enucleated and haemoglobin-filled erythroid cells were obtained from primitive HS cells. Dimethylsulphoxide (DMSO) was found to be of particular importance as an efficient differentiation inducer. The differentiation process was followed microscopically and by fluorescence-activated cell sorting (FACS). Using the micropipette aspiration technique, the elastic properties of erythroid cells were evaluated as erythropoiesis progressed. Discocyte-like cells, comprising reticulocytes and finally differentiated red blood cells, showed an about ten-fold higher membrane shear modulus compared with control cells.

Interferon-alpha combined with ketoprofen as treatment of naïve patients with chronic hepatitis C: a randomized controlled trial.

In this randomized controlled study, we evaluated the efficacy and safety of interferon-alpha combined with ketoprofen to that of interferon-alpha alone in naïve patients with chronic hepatitis C. Forty patients were randomized to receive Interferon-alpha2a (3 million units three times a week) and ketoprofen (150 mg twice a day) and 40 to receive only interferon-alpha2a at the same dose. Patients were treated for 6 months and followed up for 6 months. Response was defined by undetectable HCV-RNA in serum at the end-of-treatment and after 6 months from the completion of therapy (long term response). At the end of treatment the response was similar in the two group. However, combination treatment showed significantly higher efficacy than monotherapy in achieving long term response (10%vs 32.5%; P = 0.014). Overall adverse events were similar in the two groups. 'Flu-like syndrome was significantly less common in the ketoprofen plus interferon group which experienced a significantly higher incidence of epigastric pain'. Our results indicate that the combination of ketoprofen plus interferon is significantly more effective than interferon alone in the treatment of naïve patients with chronic hepatitis C and is well tolerated. However this combined treatment appears to be less effective than the association of pegylated IFN and ribavirin which represent the current standard treatment. Thus, the role of ketoprofen in the treatment of chronic hepatitis C needs to be further evaluated against such a treatment.

Determination of the elastic shear modulus of cultured human red blood cells.

In this study we investigated the mechanical properties of in vitro cultured red blood cells (RBCs) in a liquid system. We used human umbilical cord blood as a highly efficient source of hematopoietic stem cells (HS). Our first goal was to establish an optimal medium composition in order to yield finally differentiated RBCs, i.e. enucleated and hemoglobin-filled cells. Different stages of cell differentiation were distinguished based on morphological observations and flow cytometry measurements. By means of the micropipette aspiration technique we estimated the deformability characteristics of the cultured cells. Up to the stage of oxiphilic normoblasts they readily deformed. Reticulocytes and mature RBCs showed an enhanced stiffness as compared to RBCs obtained from donors.

In vitro effect of thymosin-alpha1 and interferon-alpha on Th1 and Th2 cytokine synthesis in patients with chronic hepatitis C.

Current evidence suggests that increased expression of Th1-associated cytokines is important for immune-mediated eradication of hepatitis C infection, while an increase in Th2-associated cytokines is associated with persistence of infection. In this study we evaluated the effects of thymosin-alpha1 (TA1), a naturally occurring thymic peptide, and interferon-alpha (IFN-alpha) on cytokine production in peripheral blood mononuclear cells from untreated patients with chronic hepatitis C. We examined the effect of incubation with TA1, IFN-alpha, or both, on production of Th1-associated cytokines (IL-2, IFN-gamma), Th2-associated cytokines (IL-4, IL-10), and synthesis of the antiviral protein 2',5'-oligoadenylate synthetase. TA1 treatment induced a significant increase in production of IL-2 and 2',5'-oligoadenylate synthetase. Smaller increases were also seen after treatment with IFN-alpha, while incubation with TA1 and IFN-alpha together led to an additive or synergistic effect. Incubation with TA1 resulted in a decrease in IL-4 and IL-10, whereas IFN-alpha increased these cytokines. The addition of TA1 to IFN-alpha significantly reversed this IFN-alpha-induced increase. Hence, TA1 treatment could benefit patients with hepatitis C infection by increasing the Th1-type response, fundamental for sustained clearance of hepatitis C; and by decreasing the Th2-type response, associated with persistence of viraemia.

Vitamin E as treatment for chronic hepatitis B: results of a randomized controlled pilot trial.

BACKGROUND AND AIMS: Interferon-alpha treatment has been the treatment of choice for chronic hepatitis with unpredictable results. Recently, Lamivudine has been licensed for use against HBV infection with good results. Unfortunately, recurrence of viremia after lamivudine withdrawal is common and prolonged treatment can induce the emergence of resistant mutant strains. It has been shown that vitamin E can increase the host immune response, and this may provide protection against infectious diseases. METHODS: We evaluated vitamin E supplementation as therapy for chronic hepatitis B in a pilot study including 32 patients. Patients were randomly allocated to receive vitamin E at the dose of 300 mg twice daily for 3 months (15 patients) or no treatment (17 patients). They were seen monthly during the first 3 months and thereafter quarterly for additional 12 months. RESULTS: The two groups were comparable at enrollment. At the end of the study period, alanine aminotransferase (ALT) normalization was observed in 7 (47%) patients in vitamin E group and only in 1 (6%) of the controls (P=0.011); HBV-DNA negativization was observed in 8 (53%) patients in the vitamin E group as compared to 3 (18%) in the control group, respectively (P=0.039). A complete response (normal ALT and negative HBV-DNA) was obtained in 7 (47%) patients taking vitamin E and in none of the controls (P=0.0019). CONCLUSION: Vitamin E supplementation might be effective in the treatment of chronic hepatitis B.

Interferon-alpha plus ribavirin and amantadine in patients with post-transplant hepatitis C: results of a pilot study.

BACKGROUND: Recurrence of hepatitis C after liver transplantation is almost constant and may lead to graft loss. The results of treatment with interferon and/or other agents have been controversial. AIMS: To evaluate the efficacy and safety of combination therapy with interferon-alpha2b (3 MU, 3 times weekly), ribavirin (600 mg daily) and amantadine (100 mg daily) in post-transplant hepatitis C. PATIENTS AND METHODS: Enrolled in the study were 9 liver transplant recipients with histologically proven recurrent hepatitis C. Patients were treated for 12 months and followed up for 6 months after treatment. RESULTS: Treatment was not tolerated: only one patient completed the planned course, two stopped therapy within the first 3 months and 6 needed a change. However, mean alanine aminotransferase levels significantly decreased during treatment and were significantly lower than baseline at the end of follow-up. One patient out of 9 (11%) achieved a biochemical and virological sustained response. Control liver biopsy showed improvement in 2/7 patients, no change in 3 and worsening in 2. CONCLUSIONS: In recurrent post-transplant hepatitis C, antiviral treatment with interferon, ribavirin and amantadine seems to be poorly tolerated. However further studies are needed before expressing any conclusion on this potentially important option.

A cell-culture reactor for the on-line evaluation of radiopharmaceuticals: evaluation of the lumped constant of FDG in human glioma cells.

UNLABELLED: A fluidized-bed cell-culture reactor with on-line radioactivity detection was developed for the in vitro evaluation of radiopharmaceuticals. The technique was applied to measure the dependency of the lumped constant (LC) of FDG on the glucose concentration in the culture medium in a human glioma cell line. METHODS: Human glioblastoma cells (86HG39) immobilized in open porous microcarriers were cultivated in a continuously operating fluidized-bed bioreactor. At different glucose concentrations in the culture medium, step inputs (0.1 MBq/mL) of FDG were performed and the cellular uptake of FDG was measured on-line and compared with analyzed samples. From these results, the LC of FDG and its dependency on the glucose concentration were calculated. RESULTS: This fluidized-bed technique enabled precise and reproducible adjustment of all relevant experimental parameters, including radiotracer time-concentration course, medium composition, pH, dissolved oxygen and temperature under steady-state conditions, and an on-line determination of the intracellular radiotracer uptake. The immobilized glioma cells formed stable, 3-dimensional, tumor-like spheroids and were continuously proliferating, as proven by an S-phase portion of 25%-40%. For further examination of the cells, an enzymatic method for detachment from the carriers without cellular destruction was introduced. In the FDG experiments, a significant dependency of the LC on the glucose level was found. For normoglycemic glucose concentrations, the LC was determined to be in the range of 0.7+/-0.1, whereas in hypoglycemia LC increased progressively up to a value of 1.22+/-0.01 at a glucose concentration of 3 mmol/L. CONCLUSION: The bioreactor represents an improved in vitro model for the on-line evaluation of radiotracers and combines a wide range of experimental setups and 3-dimensional, tissue-like cell cultivation with a technique for on-line radioactivity detection.

Development of a fixed bed bioreactor for the expansion of human hematopoietic progenitor cells.

The ex vivo expansion of hematopoietic progenitor cells is of great interest for a variety of clinical applications, e.g. bone marrow transplantation or gene therapy. Therefore it is of general interest to develop a culture system, able to mimic the in vivo hematopoesis, which is a prerequisite for long-term hematopoietic culture. Our approach was to modify a continuously perfused bioreactor for cultivation and expansion of human hematopoietic stem cells. Therefore we immobilized stromal cells (human primary stromal cells or the murine cell line M2-10B4) in porous glass carriers in a fixed bed reactor and cocultivated human hematopoietic progenitor cells for several weeks. After inoculation of mononuclear cells derived from umbilical cord blood or peripheral blood stem cells both adherent and non adherent cells were harvested and analyzed by flow cytometry and short-term colony assays. During cultivation there was a permanent production of progenitor cells and mature blood cells derived from the immobilized cells in the carriers. We could demonstrate the immobilization of hematopoietic progenitor cells of the myeloid system detectable in short-term colony assays. Additionally we could observe the expansion of very early progenitor cells (CFU-GEMM) up to 4.2-fold and later progenitor cells (CFU-GM and BFU-E) up to 7-fold and 1.8-fold, respectively.