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Biomedical subjects

Erwin Strasser

Publications and source records attributed to Erwin Strasser.

12 recordsLinked to original sources
PubMed2006

Hepatitis B vaccination status among healthy adults in Germany.

OBJECTIVES: The hepatitis B vaccination policy in Germany was intensified by the implementation of hepatitis B vaccination for adolescents in the vaccination calendar in 1995. To investigate the effect of this measure on the hepatitis B vaccination coverage of healthy adults, we analysed the hepatitis B vaccination status of blood donors. Furthermore, the reasons for vaccination and the relationship between vaccination status and age, sex, and current profession were studied. METHOD: Using a standardised questionnaire, randomly incoming whole blood donors were asked for hepatitis B vaccination status, the reason for vaccination, gender, age and current profession. Multiple logistic regression analysis with vaccination status as dependent variable and age, gender and current profession as explanatory variables was performed. RESULTS: Overall, 1519 (22.3%) of the 6812 interviewed whole blood donors were vaccinated against hepatitis B. Younger age was significantly associated with higher acceptance of hepatitis B vaccination with already 44.1% of whole blood donors aged 18-29 years being hepatitis B immunised. Beside health care workers, teaching professions and students showed the highest hepatitis B vaccination rate. Foreign travel was nearly an equivalently important reason for hepatitis B vaccination as occupational risks. CONCLUSION: The high hepatitis B vaccination coverage among young and healthy adults indicates the success of the intensified hepatitis B vaccination policy since 1995. However, concentrating education measures on individuals with lower educational level and intensifying hepatitis B vaccination in the context of foreign travel could further increase the acceptance of hepatitis B vaccination.

Adolescent↗
PubMed2006

Washing platelets with new additive solutions: aspects on the in vitro quality after 48 hours of storage.

BACKGROUND: Rare clinical conditions cause the need for washed platelet (PLT) concentrates (PCs). Saline-washed PCs can only be stored shortly, however, owing to lack of substrates for PLT metabolism. New PLT additive solutions (PASs) contain such substrates and might be used alternatively. The in vitro quality of apheresis PCs washed with Composol-PS or modified PAS-III (PAS-IIIM) stored up to 48 hours after wash was compared. STUDY DESIGN AND METHODS: Twelve blood donors underwent two apheresis procedures (A and B) collecting 6.0 x 10(11) PLTs in 500 mL of plasma with a least 2 weeks in between. The PCs collected by Apheresis A were stored for 3 days and then split in two equal units before washing with Composol-PS or PAS-IIIM. The PCs collected by Apheresis B were split after collection. One unit was released for transfusion and 1 unit was stored unwashed up to Day 6 and used as reference unit. In vitro testing was performed before and after washing as well as 24 and 48 hours after wash. RESULTS: After 48 hours of postwash storage, the units washed with either PAS showed acceptable results for hypotonic shock response (HSR), P-selectin expression, and pH, whereas PLT aggregability was significantly impaired. Throughout the storage, unwashed units showed better in vitro quality. HSR and P-selectin expression were similar before and immediately after the washing procedure. CONCLUSION: Based on these in vitro results, 48-hour postwash storage of washed PCs with the two PASs seems to be feasible. In vivo recovery studies, however, must confirm this finding in the future.

Blood Platelets↗
PubMed2006

Impact of different hold time before addition of platelet additive solution on the in vitro quality of apheresis platelets.

BACKGROUND: The quality of platelets (PLTs) stored in PLT additive solution (PAS) is dependent on the type and proportion of the used PAS. No data are available as to whether a different hold time before the addition of PAS to hyperconcentrated PLT suspensions has an impact on PLT quality. The in vitro quality between single-donor PLT concentrates was compared with two different hold times with two PASs. STUDY DESIGN AND METHODS: On two occasions, 6x10(11) PLTs in 150 mL of plasma were collected from 20 blood donors. The units were split into two equal parts, and 140 mL of PAS-II or PAS-IIIM (randomized sequence) was added after 2 or 8 hours resulting in a PAS proportion of 65 percent. On Days 1, 5, and 7, glucose and lactate concentration, pH value, PLTs' P-selectin expression, response to hypotonic shock, and release of transforming growth factor-beta1 were determined. RESULTS: On all days, the lactate concentrations were higher and pH values were lower in units with an 8-hour hold time, whereas the results of in vitro tests relating to the in vivo viability and activation of PLTs were similar for both groups. PAS-IIIM-stored PLTs showed a lower glycolytic activity and better results in all performed in vitro tests than PAS-II-stored PLTs. CONCLUSIONS: Although the metabolism of glucose was enhanced during hold time, the differences between both hold time groups are not meaningful from a biological viewpoint. Therefore, an 8-hour hold time is feasible. PLT storage in PAS-IIIM results in a PLT in vitro quality superior to that of PLTs stored in PAS-II.

Blood Platelets↗
PubMed2005

Efficient elutriation of monocytes within a closed system (Elutra) for clinical-scale generation of dendritic cells.

Dendritic cells (DC) are promising tools for the immunotherapy of cancer. The induction of tumor-specific T cells and clinical regressions have already been observed in early phase I/II vaccination trials. As DC vaccination is now facing trials with larger patient collectives it becomes increasingly important to obtain large numbers of cells suitable for therapeutic applications under labor- and cost-effective conditions. We describe here a procedure that uses a novel cell separator (Elutra, Gambro BCT) to enrich monocytes from an entire apheresis product within one hour. Cells are separated on the basis of size and to a lesser extent density, by elutriation in a 40-ml conical chamber. The total monocyte recovery following elutriation (n = 6) was 98.53% (+/-8.07%), the recovery in the monocyte-rich fraction 75.45% (+/-11.31%), and the mean purity 82.95% (+/-6.01%). These monocytes can be cultured either in conventional culture dishes or in closed cell culture bags and differentiated, by using GM-CSF+IL-4 followed by a maturation cocktail composed of IL-1beta+IL-6+TNF-alpha+PGE2, into fully mature DC. The Elutra separator allows for fast and easy enrichment of monocytes within a closed system. Subsequently, elutriated monocytes can be successfully cultured into phenotypically and functionally mature DC for immunotherapeutic approaches. The method neither requires a density gradient step to enrich PBMC from leucapheresis products nor does it apply (xenogeneic) antibodies to target monocytes. Isolation of monocytes with Elutra may greatly facilitate future DC-based vaccination approaches.

Cell Differentiation↗
PubMed2005

Plateletpheresis does not cause long-standing platelet-derived growth factor release into the donor blood.

BACKGROUND: Recently, long-standing elevations of soluble growth factors released from platelets (PLTs) after contact with artificial surfaces during dialysis were described. They could be jointly responsible for the high frequency of death from cardiovascular diseases in dialysis patients. There are no comparable data on the extent and the duration of a growth factor release by plateletpheresis procedures. STUDY DESIGN AND METHODS: A total of 37 plateletpheresis procedures were performed with two different devices. PLT-derived growth factor (PDGF) isoform AB, transforming growth factor (TGF)-beta1, and beta-thromboglobulin (beta-TG) were measured in the donors' plasma samples, and PLT activation and function were measured by cytometry and aggregometry before and after plateletpheresis and 1 and 24 hours later. RESULTS: Before apheresis, the following mean plasma levels were found: beta-TG, 98.6 +/- 37.3 IU per mL; PDGF-AB, 71.5 +/- 38.5 pg per mL; and TGF-beta1, 2.24 +/- 0.80 ng per mL. At the end of the apheresis procedures, the mean PDGF-AB level had increased by a factor of 1.8 (p < 0.05). One hour later, the mean PDGF-AB level had normalized again. No significant change in the levels of beta-TG and TGF-beta1 was found by the apheresis procedures. There was no influence of the blood cell separator type on the results. CONCLUSION: Only a slight and rapidly reversible increase in soluble PDGF-AB was found during plateletpheresis and no increase in soluble TGF-beta1 and beta-TG was found. This change should not be harmful to the donor.

Blood Donors↗
PubMed2003

Cord blood processing with an automated and functionally closed system.

BACKGROUND: Umbilical cord blood processing with standard centrifugation techniques is performed in open systems and results in varying cell and volume recoveries. STUDY DESIGN AND METHODS: Forty umbilical cord blood donations were randomly assigned to processing either with a microprocessor-controlled cell separator equipped with closed disposables or with a manual separation procedure in blood bags. The collection efficiency of nucleated cells, MNCs, RBCs, and CD34+ cells and the processing time were analyzed. RESULTS: Using the cell processor, mean collection efficiencies were 78.6 +/- 24.9 percent for nucleated cells, 77.4 +/- 27.8 percent for MNCs, 55.5 +/- 14.6 percent for RBCs, and 83.6 +/- 32.5 percent for CD34+ cells, while they were 73.1 +/- 13.2 percent for nucleated cells, 78.1 +/- 14.9 percent for MNCs, 26.0 +/- 12.2 percent for RBCs, and 77.0 +/- 17.6 percent for CD34+ cells when using the standard centrifugation technique. The processing time was about 20 minutes for automated processing and 60 to 80 minutes for the standard centrifugation technique. CONCLUSION: Using the new cell processor, the collection efficiencies for nucleated cells, MNCs, and CD34+ cells are similar to those obtained by established centrifugation techniques while the RBC reduction is less effective. The main advantages of the new systems are the closed system, the more standardized processing procedure, and a significantly shorter processing time.

Antigens, CD34↗
PubMed2003

Collection of WBC-reduced single-donor PLT concentrates with a new blood cell separator: results of a multicenter study.

BACKGROUND: A new cell separator (COM.TEC, Fresenius) was recently developed aimed at efficient collection of WBC-reduced single-donor PLT concentrates (SDPs). STUDY DESIGN AND METHODS: Five German centers collected 554 WBC-reduced SDPs with help of the COM.TEC cell separator. Two multicenter cell counting studies were performed at the beginning and at the end of the study to document uniform counting results among the participating centers. RESULTS: A total of 441 (79.6%) PLT collections were included in the study according to the protocol. A total of 342 single-dose and 99 double-dose SDPs were collected. For single-dose SDPs, an average blood volume of 2826 +/- 409 mL was processed in a donation time of 55 +/- 11 minutes. Mean PLT yield of these products was 3.11 x 1011+/- 0.40 x 1011 and the WBC contamination was 0.11 x 106+/- 0.20 x 106. For double-dose SDPs (PLT count, 5.29 +/- 0.93 x 1011), 3943 +/- 639 mL was processed. The average difference between the target and the collected PLT concentration was -2.8 +/- 12.0 percent for single-dose SDPs and -1.8 +/- 9.5 for double-dose SDPs, respectively. The collection efficiency was 53.7 +/- 5.8 percent for single-dose SDPs and 58.2 +/- 6.2 percent for double-dose SDPs. If all results of each sample from the counting study were set to unity (to the mean over all centers), most PLT determinations were very similar to the mean, for example, near or 1 if set to unity. CONCLUSION: The COM.TEC machine makes it possible to obtain WBC-reduced SDPs that comply with current standards.

Blood Cell Count↗
PubMed2002

Large-scale generation of mature monocyte-derived dendritic cells for clinical application in cell factories.

Dendritic cells (DC) are increasingly used for the immunotherapy of cancer. Both the induction of tumor-specific T cells and some clinical regressions have been observed in early phase I/II trials by using either DC isolated from blood, DC generated from CD34+ precursors ex vivo, and most frequently, by employing monocyte-derived DC. As DC vaccination is now awaiting phase II/III trials with larger patient collectives, it becomes increasingly important to overcome prior limitations such as the repetitive, labor-intensive generation of DC in a large number of open culture vessels. We describe here as a result of several years of optimization, in detail, a procedure that uses the so-called Nunc cell factories to process a whole apheresis product, labor- and cost-effectively in a quasi-closed system to reproducibly generate (by using GM-CSF+IL-4 followed by a maturation cocktail composed of IL-1beta+IL-6+TNF-alpha +PGE(2)) large numbers (8.32+/-3.8% of input peripheral blood mononuclear cells (PBMC)) of mature (>85% CD83+), monocyte-derived DC that can be successfully cryopreserved. Our report is based on the processing of >100 aphereses including 52 unselected aphereses in advanced melanoma patients. This allows us also to suggest meaningful quality and validation criteria. The DC generation method appears particularly promising as respective DC vaccination proved to be immunogenic in cancer patients and cell factories can readily be converted to a fully closed system by using appropriate valves, tubings, and bags.

Blood Component Removal↗