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W Sibrowski

Publications and source records attributed to W Sibrowski.

At least 37 records · Page 2Linked to original sources
PubMed1999

Efficacy and safety of simultaneous immunomagnetic CD34+ cell selection and breast cancer cell purging in peripheral blood progenitor cell samples used for hematopoietic rescue after high-dose therapy.

We have established a new simultaneous positive/negative selection procedure using the Baxter Isolex 300i system. We tested its tumor cell (TC) purging efficacy by tumor contamination tests ex vivo and its safety in a group of 17 breast cancer (BC) patients by measuring hematopoietic recovery after high-dose (HD) therapy and autologous stem cell rescue with the selected cells. Tumor contamination tests resulted in a TC depletion of 4.1-6.0 log steps. The CD34+ cell yield in this experimental setting was 38.9-91.5%, and the CD34+ cell purity was 86.0-96.0%. In a group of 17 BC patients (5 high-risk adjuvant, > or = 10 lymph nodes positive, and 12 metastatic), we processed leukapheresis products (LPs) by simultaneous positive/negative selection. In these clinical samples, the mean CD34+ cell yield was 56.2% (range, 14.0-80.1%), and the CD34+ cell purity was 94.5% (range, 69.0-99.8%). Additionally, we screened samples of the patients' LPs before and after the purging procedure for contaminating TC by immunocytochemistry. In 15 of 17 tested cases, TCs were detectable prior to the purging procedure. After the procedure, we could not detect residual TCs in 16 of 17 cases. In one case, we found a highly reduced number of TCs. Furthermore, we evaluated the times for hematopoietic reconstitution in a group of five BC patients in the high-risk adjuvant situation who underwent HD chemotherapy and hematopoietic rescue with positive/negative selected stem cells and compared it with our own data from 10 BC patients who, after identical HD therapy, received only positively selected CD34+ cells and 14 patients who, after identical HD therapy, received autografts purged by incubation with toxic ether lipids (ET-18-OCH3). In all groups, a leukocyte count of >2000 cells/microl was reached at day +10. A platelet count of > 50,000 cells/microl was reached at day +12 in the ET-18-OCH3 group and at day +14 in the other two groups. Furthermore, 12 patients with metastatic disease rescued with positive/negative selected stem cells after HD therapy also showed fast and comparable hematopoietic recovery. The new simultaneous immunomagnetic positive/negative selection using a closed system is effective and safe. Processing LPs leads to a similar CD34+ cell yield, a higher TC depletion compared to standard CD34+ cell selection, and no delay in hematopoietic recovery.

Antigens, CD34↗
PubMed1998

The influence of different erythrocyte lysing procedures on flow cytometric determination of CD34+ cells in umbilical cord blood transplants.

Since the correct determination of CD34+ cells is of great clinical importance for successful transplantation with haematopoietic progenitor cells (HPCs) from cord blood, we investigated the influence of different erythrocyte lysing techniques on the quantification of CD34+ cells in umbilical cord blood. Flow cytometric determinations of CD34+ cells were performed from 20 cord blood samples, using three different erythrocyte lysing procedures and two monoclonal CD34 antibodies (n = 360). Flow cytometric analysis showed characteristic patterns of the forward (FSC) and side (SSC) scatter light properties for the leucocyte subsets for each of the investigated erythrocyte lysing procedures, indicating that these reagents cause different morphological changes on leucocytes. Furthermore, significant differences of CD34+ cell counts were obtained for identical samples using different lysing techniques (P = 0.001 and P = 0.002). In some cases, a more than 100% difference was found comparing different erythrocyte lysing procedures. In contrast, the determination of CD34+ cells by two CD34 antibodies showed a good reproducibility without significant differences between both antibodies for each of the erythrocyte lysing techniques. We conclude that the erythrocyte lysing procedure represents a very critical and important step for accurate determination of CD34+ cells in whole blood samples. Especially for the quantification of HPCs in cord blood transplants, this influence may be of high clinical relevance.

Antigens, CD34↗
PubMed1998

Suppression of panel-reactive antibodies by treatment with mycophenolate mofetil.

"Panel Reactive Antibody" (PRA) testing is commonly used to assess the pretransplant antibody status in order to estimate the risk of an adverse humoral response following transplantation. We report on a female patient with end-stage cardiac failure suffering from acute myocarditis who underwent implantation of a left-ventricular assist device (Novacor, Baxter Healthcare Corp. Oakland, CA). During evaluation for heart transplantation, a PRA level of 50-70% was detected. After treatment with mycophenolate mofetil at a dosage of 2 g daily, PRA levels declined within one week to 0-5%, and remained low after discontinuation of the immunosuppressive drug. We feel that pretreatment of patients with elevated PRA levels with mycophenolate mofetil is well justified.

Acute Disease↗
PubMed1998

[Peripheral blood stem cell transplantation as an interdisciplinary challenge--theory and practice].

High dose chemotherapy with consecutive autologous peripheral blood stem cell transplantation becomes increasingly important for the treatment of hematological diseases and solid tumors. A complete remission or at least a prolonged survival can be achieved for numerous malignant diseases by an intensification of chemo- and radiotherapy. Therefore, the autologous peripheral blood stem cell transplantation (PBSCT) represents an elementary precaution to reduce the therapy-associated aplasia by administration of hematopoietic precursor cells. Both, high dose chemotherapy with consecutive PBSCT demands great clinical experience and the collection, processing and positive selection of blood stem cells is a challenge for the Transfusion Medicine. Correct handling and utilization of blood stem cells for clinical and laboratory purposes (e.g. positive selection) must be guaranteed, since each restriction of the function of processed blood stem cells may lead to an insufficient engraftment after PBSCT. Therefore, the clinical divisions of the University Hospital Münster are planning and practising peripheral blood stem cell transplantations in cooperation with the Department of Transfusion Medicine. The collection, processing and quality control are performed by the Department of Transfusion Medicine in close contact with the other clinical departments, who subsequently perform high dose chemotherapy and peripheral blood stem cell transplantations.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Efficacy and kinetics of bone marrow processing and enrichment of haematopoietic progenitor cells (HPC) by a large-volume apheresis procedure.

We investigated the efficacy of bone marrow (BM) processing by an automated large-volume apheresis procedure (6 x original BM volume) in 10 paediatric and adult patients undergoing BM harvesting before myeloablative therapy. Volume-dependent kinetics during apheresis were analyzed by sequential collection of processed cells into a six-fold collection bag system with consecutive analysis of the single bags. BM processing resulted in an 83.3% (+/- 21) recovery of mononuclear cells (MNC), a 97.9% (+/- 1.1) reduction of erythrocytes (RBC) and a 87.7% (+/- 2.9) volume reduction. To determine volume-dependent kinetics of haematopoietic progenitor cell (HPC) enrichment during apheresis, leukocytes (WBC), mononuclear cells (MNC), CD34 cells and colony-forming cells (CFU-GM) were serially quantitated in subsequent collection bags. Large-volume BM processing significantly enhanced absolute yields of CD34+ cells (mean: 4.01 (+/- 2.81) x 10(6)/kg bw) and CFU-GM (mean: 1.92 (+/- 1.47) x 10(4)/kg bw) compared with the standard procedure (3 x BM volume) by 26.9% (+/- 10.9) and 27.2% (+/- 11.6), respectively. We concluded that large-volume apheresis for BM processing is an efficient technique significantly improving the yields of haematopoietic progenitor cells (HPC) without any relevant changes in the purity of the final product. Moreover, sequential collection and analysis of HPC represents a good model to investigate the volume-dependent kinetics and efficacy of BM processing.

Adolescent↗
PubMed1997

A sequence-specific polymerase chain reaction assay for mitochondrial DNA polymorphisms in human platelets and white cells.

BACKGROUND: Because mitochondria are abundant in white cells and are also present in platelets, polymorphic sequences in mitochondrial DNA (mtDNA) represent a unique target for polymerase chain reaction (PCR)-based detection of donor material. STUDY DESIGN AND METHODS: A PCR assay was developed that uses sequence-specific primers (SSP) focused on two continent-specific mtDNA polymorphisms. Results were validated by the use of informative restriction endonucleases. Three commercially available methods to extract mtDNA from white cell-reduced human platelets was compared. In preparation for in vivo studies, in vitro mixing studies designed to mimic transfusion were conducted to investigate the performance of the SSP-PCR assay. RESULTS: The gene sequences of two representative examples of amplicons obtained with the new SSP-PCR matched the sequence expected from the published genetic code. Fifteen individuals were classified as either positive (n = 6) or negative (n = 9) for the Asian polymorphism by the use of published primers known to flank the polymorphic site followed by digestion with appropriate restriction enzymes. Results with SSP-PCR were nearly perfectly concordant with those of restriction enzyme analysis. Although the use of three DNA extraction methods allowed the preparation of mtDNA that was suitable for PCR, large and consistent differences (ranging from 10- to 1000-fold) in endpoint sensitivity were found. In vitro mixing studies reproducibly documented that the SSP-PCR assay could detect as little as 1 percent of donor platelets mixed with recipient blood. CONCLUSION: PCR-SSP can be reliably used to identify human mtDNA polymorphisms. By optimization of the method of mtDNA extraction, the sensitivity of PCR-SSP assay was greatly increased. This assay should prove useful in investigations of allogeneic platelet transfusions without cell labeling. It may also be applied to studies of the donor cell microchimerism that follows transfusion or transplantation.

Asian People↗
PubMed1996

[Functional evaluation of erythrocytic antibodies by photometric detection of erythrophagocytosis in the monocyte monolayer assay].

In haemolytic disease of newborn (erythroblastosis fetalis) the in vivo behaviour of erythrocytic IgG antibodies is of particular significance. The monocyte monolayer assay (MMA), which determines by microscopy the number of erythrocytes phagocytosed by monocytes, is an important functional test for the qualitative assessment of erythrocytic IgG antibodies. We set up a photometric MMA and compared it with the microscopic MMA. In both tests we employed commercially available rhesus antibody sera and examined 8 sera of pregnant women with mild and severe courses of haemolytic disease of newborn by the photometric MMA. Good agreement was found between the microscopic and photometric MMA (r = 0.93). Over and above this the photometric MMA correlated with the course of haemolytic disease of newborn in 7 out of 8 cases (with one false-positive finding). The photometric technique permits rapid, sensitive and reproducible determination of erythrophagocytosis in microtitre plates. This method is based on the photometric detection of haemoglobin of phagocytosed erythrocytes via a peroxidase reaction. Standardised photometric MMA could in future be more widely applied especially in haemolytic disease of newborn for the functional characterisation of erythrocytic antibodies, the incidence of intra-assay and inter-assay errors being low.

Coombs Test↗
PubMed1996

Improved automated bone marrow processing and enrichment of CD34+ cells by a large-volume apheresis procedure.

We investigated the efficacy of bone marrow (bm) processing by a large-volume apheresis procedure using a self constructed sixfold collection bag system for sequential cell collection and analysis for 5 pediatric patients. Quantitation of leukocytes (WBC), CD34+ cells and colony-forming cells (CFU-GM) within the single bags showed a relative time-dependent decrease of all cell fractions during leukapheresis, whereas the relative amount of mononuclear cells (MNC) droped only slightly. At the same time the large volume apheresis (6 x original bm-volume) clearly enhanced the absolute yield of CD34+ cells compared to the standard procedure (3 x bm-volume) for more than 20%. We conclude that large-volume apheresis for bm processing is an efficient technique to improve the yields of progenitor cells.

Adolescent↗
PubMed1994

[New diagnostic developments in infection serology].

New developments concerning the diagnostic of virus-transmitted diseases led to a strong improvement of virus security in hemotherapy. The introduction of additional virus antigens associated with the core region of the hepatitis C virus (HCV) resulted in an increase of sensitivity and especially of specificity of second-generation enzyme immuno assays (EIAs). The recombinant immunoblot (RIBA) with 4 synthetic antigens continues to be the most accepted confirmatory test in the field of HCV diagnostic. Beside the simultaneous detection of specific IgG and IgM, especially the HIV-p24 antigen test is discussed concerning HIV-1, -2 diagnostic in order to shorten the 'windows period' in the early time of infection. It is assumed that the HIV-p24 antigen test is not able to effectively improve virus security in areas with low HIV-1, -2 prevalence.

AIDS Serodiagnosis↗
PubMed1994

[A retrospective study of the practice of "look-back" procedures, on the incidence of HIV-1/2-positive blood donors and the risk of transfusion-associated HIV infection in public-community blood banks in Germany].

OBJECTIVE: 'Look-back' investigations can reveal and confirm transfusion-transmitted infectious diseases and provide data for risk calculations of blood transfusions. DESIGN: In 1993 we distributed a questionnaire to all governmental and communal blood transfusion services in Germany. The questionnaire comprised questions about the methods, numbers and results of look-back investigations in case of HIV-1/2-positive blood donors with previous donations and in case of HIV-1/2-positive recipients of blood transfusions. The questionnaire was returned by almost all blood transfusion services (n = 75). One additional institution briefly informed us by telephone. SETTING: All governmental and communal blood transfusion services in Germany. PATIENTS: All recipients of blood or blood products in the years from 1985 till the end of 1992 who were treated in hospitals supplied by the transfusion services defined above. INTERVENTIONS: None. RESULTS: All blood transfusion services included have performed look-back studies since 1985. The methods used varied considerably. The interval of looking back mostly was sufficient. A main problem was the poor documentation in the medical records. The incidence of HIV-1/2-positive blood donations decreased from 11.6/100,000 in 1985 to 3.4/100,000 in 1992. Only 7 of 73 transfusion-transmitted HIV infections derived from transfusions after the introduction of HIV testing (October 1985). Since then the risk of transfusion-transmitted HIV infection can be calculated as 1/800,000 whole-blood donations of governmental and communal blood transfusion services. CONCLUSIONS: Since the introduction of HIV testing the risk of transfusion-transmitted HIV infection in Germany has been very low, at a rather stable rate of 1/800,000. The data from the look-back studies confirm the previous estimations of the risk of transfusion-transmitted HIV infections, which was calculated by the HIV incidence in the donor population. Nevertheless there is a need for standardization of look-back investigations.

AIDS Serodiagnosis↗
PubMed1994

[Bacterial infection within the scope of hemotherapy].

OBJECTIVE: The purpose of this article is to present a survey of bacterial infections caused by hemotherapy. DATA SOURCES: Original papers as well as review articles from international investigations based on literature data banks. RESULTS: As there exist only a few studies about transfusion complications caused by bacteria you only can find sporadic reports. Surely immunocompromised recipients have high risk to be hurt. Causing bacteria are various but Staphylococci, Yersinia, Serratia and Pseudomonas species often are found. Especially platelet concentrates give higher infection risk because storage at room temperature is obligatory. This fact makes growth conditions more comfortable. Strict hygienic measures, extension of donor screening and pointed quality control are capable to decrease the risk of transfusion complications. CONCLUSIONS: Exact indications and a clear strategy evaluating the transfusion reports and routine bacteriological control are necessary to prevent infections caused by hemotherapy.

Bacterial Infections↗
PubMed1994

[Risk of infection in hemotherapy].

For some years, public interest has focused on transfusion-transmitted HIV. German blood donors are now selected and show only very low incidences in HIV and hepatitis. Only one per million donors seems to transmit HIV. The remaining risk of post-transfusion hepatitis is estimated to range between 1:10,000 and 1:100,000. Some new diagnostic tests might reduce the danger of transfusion-transmitted infections. Screening donors for anti-HBc is a well accepted tool to decrease post-transfusion hepatitis B. The HIV-p24-Ag test is expensive and only of doubtful value. Donor recruitment should be improved in future.

Acquired Immunodeficiency Syndrome↗