Dirk Hartwig

Evidence for de novo synthesis of cytokines and chemokines in platelet concentrates.

Background and Objectives Inflammatory cytokines in platelet concentrates (PC) may cause side‐effects such as febrile non‐haemolytic transfusion reactions. The maximum white blood cell (WBC) content tolerable to avoid the accumulation of cytokines, and whether these cytokines originate from degranulating leucocytes or de novo synthesis during storage, had not been investigated prior to this study.

Epitheliotrophic capacity of a growth factor preparation produced from platelet concentrates on corneal epithelial cells: a potential agent for the treatment of ocular surface defects?

BACKGROUND:  Topical application of serum eye drops has been reported to accelerate healing of persistent ocular surface defects. It is supposed that growth factors in serum support the wound healing process. Platelets (PLTs) are rich in growth factors and easily available as PLT concentrates (PCs) from blood banks. Therefore, growth factor preparations from PCs may serve as a new and superior therapeutic agent for such defects.

A novel RT-PCR for reliable and rapid HCV RNA screening of blood donations

BACKGROUND: The objective of this work was to develop a novel and highly sensitive RT‐PCR method that is suitable for HCV RNA screening of blood donations according to the criteria released by the Paul Ehrlich Institute, the federal licensing agency of Germany, for routine HCV NAT.

In vitro proliferation and differentiation of human CD34+ cells from peripheral blood into mature red blood cells with two different cell culture systems

BACKGROUND: An in vitro erythropoiesis assay is a powerful tool for investigating red blood cell (RBC) development and diseases of the erythroid lineage. Most assays, however, failed in either proliferation or terminal differentiation. Here two liquid cultures (LCs) for in vitro generation of RBCs from peripheral blood CD34+ cells were compared.

Effect of Various Platelet Preparations on Retinal Müller Cells

PURPOSE Peeling of the internal limiting membrane is the treatment of choice for macular holes. Fresh platelet suspension (PS) is used to support wound healing in persistent macular holes. The concentration of growth factors in fresh, frozen, and thrombin-activated PSs were compared, to optimize their trophic potential and examine their capacity to support proliferation, migration, and contraction of human retinal Müller cells. METHODS The concentration of various growth factors in frozen PS, thrombin-activated PS, and plasma were evaluated by ELISA. The effect of these preparations on proliferation, migration, and contraction of human Müller cells were evaluated with an ATP-assay, a colony-dispersion assay, and a detached collagen gel contraction assay respectively. Plasma was tested as a control. RESULTS Frozen and thrombin-activated PSs contained significantly more EGF, TGF-beta1, and PDGF than did plasma. The highest concentrations of EGF and FGF were found in frozen PS. All platelet preparations and plasma supported cell growth significantly better than the control, which was serum-free culture medium. Müller cells migrated better when incubated with thrombin-activated PS than with any other test solution. Contraction was extremely strong after incubation with fresh PS compared with plasma or thrombin-activated or frozen PSs. CONCLUSIONS Frozen and thrombin-activated PSs may be suitable alternatives to fresh PS for persisting macular holes, due to their superior effect on Müller cell migration.

Recommendations for optimized settings of the Amicus Crescendo cell separator for the collection of CD34+ progenitor cells

BACKGROUND: CD34+ PBPCs for autologous transplantation purposes are collected by leukapheresis procedures on automated cell separators. In this study, the influence of different parameters on collection efficiency (CE) of the Amicus Crescendo cell separator (Baxter) was investigated.

Improvement of the precision in CFU-GM and BFU-E counting by flow cytometry-based standardization of short-term culture assays.

The counting of colony-forming units granulocyte-macrophage (CFU-GM) and burst-forming units erythrocyte (BFU-E) provides substantial in vitro information about the graft quality after peripheral stem cell transplantation (PBSCT). By using different techniques for culturing and scoring, high inter- and intralaboratory coefficients of variation (CV) are frequently reported. We minimized the imprecision by using flow cytometry-based incorporation of constant numbers of CD34(+) cells per culture dish instead of the formerly used mononuclear cells. Our results show acceptable CVs for CFU-GM (12.3%) and for BFU-E (13.3%) based on this seeding technique, which contributes to fulfilling the demands of a quality assurance system in stem cell laboratories.