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Biomedical subjects

T Zeiler

Publications and source records attributed to T Zeiler.

At least 55 records · Page 3Linked to original sources
PubMed1994

Relation between leucocyte depletion and storage.

We intended to answer two questions: (1) Does storage time of platelet concentrates (PCs) influence the efficacy of leucocyte depletion by filtration? (2) Does pre-storage leucocyte depletion by filtration of PCs improve the post-storage quality? To this end we tested in parallel the halves of 10 double-sized PCs, one half stored after filtration through a polyester filter (PL 50, Pall), the other half filtered after a 5-day storage period. Efficacy of leucocyte depletion showed to be independent of the age of PCs, and pre-storage leucocyte depletion of PCs was not able to improve the quality of PCs stored for 5 days, as long as the leucocyte contamination of unfiltered PCs was lower than 0.5 x 10(8)/unit.

Adenosine Diphosphate↗
PubMed1994

Are single-needle protocols equivalent to dual-needle protocols for platelet apheresis?

In light of the increasing demands being placed on cytapheresis donors and their occasional venous problems, it has become necessary to use 1-needle in addition to 2-needle separation techniques in thrombocytapheresis. We therefore compared five 1-needle and three 2-needle programs on four different cell separators and found that meanwhile both the platelet yields and the leukopenia (controlled by Nageotte chamber counting) of the products obtained with the 1-needle technique are equivalent to those obtained using the 2-needle technique, as long as the program is suitably adjusted.

Blood Cell Count↗
PubMed1994

Automated bone marrow concentration using the Fresenius AS 104 blood cell separator.

We concentrated freshly taken bone marrow (BM) pooled from 21 patients from an original 1.265 ml (+/- 537 ml) down to 128 ml (+/- 36 ml) within 40-70 min with a modified version of the 'grancollect protocol' on the Fresenius AS 104 blood-cell separator using the P1-Y set. An average of 47% (+/- 21%) fo the initially present mononuclear cells and 68% (+/- 47%) of the colony-forming cells could be obtained in the concentrate. The erythrocyte concentration was reduced to 7% (+/- 4%) of the original amount. The technique described is very effective and makes is possible to obtain a BM cell population that is suitable for both immunomagnetic purging and cryopreservation or transplantation, e.g. in the case of blood group incompatibility.

Automation↗
PubMed1994

[MLC reactivity demonstrates transfusion-induced immunosuppression].

The improved graft survival in preoperatively transfused renal transplant recipients led to the hypothesis that blood transfusions have an immunosuppressive effect. We examined 12 patients undergoing cardiac surgery, who received autologous red cells and one homologous HLA class-I-matched platelet concentrate. None of these patients produced red cell or lymphocytotoxic antibodies. Using the mixed lymphocyte culture (MLC) we observed a reduced lymphocyte responce to cells of the platelet donor during the first 4 days after transfusion. The MLC reactivity recovered on days 4-5 to the initial strength and reached over 200% of the initial strength from day 6 on. It must be assumed that these changes in MLC reactivity represent the early signs of the transfusion-induced immunosuppression. As intraoperative transfusions might correlate with cancer relapse, further studies must show whether this immunosuppressive effect can be avoided by the application of filtered leucocyte-depleted red cell transfusions.

Blood Transfusion↗
PubMed1994

[Effect of various rabbit complement batches of HLA class I antigen determination in lymphocytotoxicity testing].

HLA class I lymphocytotoxicity testing is strongly complement-dependent. We tested 13 commercially available rabbit complement batches (7 distributors) using a panel of 14 donors with decisive patterns of HLA antigens. We defined a scoring system that weights the different possible faulty reactions. The rating score ranged from 12.45 to 46.55 (median 16.09). Comparing the reactions in batches with low and high rating scores gave statistically significant differences (chi 2 test, p < 0.05). Our complement reaction score may be helpful to find the optimal complement batch for HLA class I lymphocytotoxicity testing.

Animals↗
PubMed1994

[Flow cytometry quality control in stem cell separation].

Peripheral blood-derived haematopoietic stem cells (PBSC) are used as an alternative to bone marrow stem cells for autologous transplantation. One of the most important prerequisites for successful PBSC separation is the precise determination of the optimal separation days. As we previously demonstrated that neither PLT counts nor WBC counts in the peripheral blood (PB) are of predictive value for the amount of colony-forming cells (CFC) in the patients' PB, we started a daily monitoring of CD-34-positive cells to determine the beginning of the separation series. In addition to routine cell counts and CFU testing we assessed the number of CD 34+ in the PBSC concentrates to ascertain the number of separations needed for each patient. Due to the strong correlation of CD 34+ cells to CFC it is possible to predict the number of CFC collected within 2 h after finishing the PBSC separation and to calculate the efficiency of the separation for quality control.

Colony-Forming Units Assay↗
PubMed1993

Automated processing of human bone marrow grafts for transplantation.

Prior to purging or cryopreservation, we concentrated 21 bone marrow (BM) harvests using a modification of the 'grancollect-protocol' of the Fresenius AS 104 cell separator with the P1-Y set. Within 40-70 min, the initial marrow volume of 1,265 ml (+/- 537 ml) was processed two to three times. A mean of 47% (+/- 21%) of the initial mononuclear cells was recovered in a mean volume of 128 ml (+36 ml). The recovery of clonogenic cells, measured by CFU-GM assays, was 68% (+/- 47%). Red blood cells in the BM concentrates were reduced to 7% (+/- 4%) of the initial number. The procedure was efficient and yielded a BM cell fraction suitable for purging, cryopreservation and transplantation. At this time, 10 of the 21 patients whose BM was processed using this technique have been transplanted. Seven of these 10 patients have been grafted using the BM alone. Three of the 10 patients showed reduced cell viability and colony growth in the thawed BM samples, and therefore obtained BM and peripheral blood-derived stem cells. All transplanted patients showed an evaluable engraftment, achieving 1,000 granulocytes per microliter of peripheral blood in a mean of 18 days.

Automation↗
PubMed1993

Sporadic occurrence of Diego A antigens and antibodies in Berlin.

BACKGROUND: The antigen Dia is common among Mongols (5-12%), but rare in Caucasians (< 1%). OBJECTIVE: The accidental discovery of Diego A (Dia) antibodies in a South American tourist and in an elderly German patient prompted us to investigate the frequency of Dia antigens in the German population. DESIGN: 1,352 German random blood donors, all living in Berlin or in the areas around, were tested for the presence of the Dia antigen on their red blood cells. All donors were Caucasians. RESULTS: Dia was found in 12 individuals (0.89%). CONCLUSIONS: We think that Dia is a low-frequency antigen in the European population. The admixture of Mongol genes following wars or migration is only of low or no importance.

Aged↗
PubMed1993

[Mobilization of hematopoietic stem cells in peripheral blood by leukapheresis].

To improve the separation results of peripheral blood stem cells (PBSC), cytokines (GM-CSF, G-CSF or IL3) can be administered to patients. The most important prerequisites for successful PBSC separation are daily monitoring of CD-34-positive cells to determine the separation days and the use of optimized separation programs. To improve the performance of the cell separation, we increased the process volume to more than patients' blood volume and obtained increased MNC and CFU recoveries. In most cases, we collected more cells than the preseparation number of circulating cells. We therefore conclude that large-volume PBSC separation itself mobilizes hematopoietic progenitor cells.

Antigens, CD↗
PubMed1992

Bone marrow processing with the Fresenius AS 104: initial results.

Prior to purging, cryopreservation, or ABO-incompatible bone marrow (BM) transplantation, we have concentrated 23 BM harvests using a modification of the "grancollect-protocol" and the recently available bone marrow stem cell (BMSC) protocol of the Fresenius AS 104 cell separator with the P1-Y set. Within 40-70 minutes, the initial marrow volume of 922 ml (+/- 408 ml) was processed two to three times. A mean of 59% (+/- 20%) of the initial mononuclear cells was recovered in a mean volume of 119 ml (+/- 31 ml). The recovery of clonogenic cells, measured by CFU-GM assays, was 98% (+/- 80%). Red blood cells in the BM concentrates were reduced to 8% (+/- 4%) of the initial number. The procedure was efficient and yielded a BM cell fraction suitable for purging, cryopreservation, and transplantation. All transplanted patients showed fast and sustained engraftments after autologous or allogeneic BM transplantation.

Bone Marrow Cells↗
PubMed1992

Bone marrow purging prior to autologous transplantation.

Our data suggest that ex vivo bone marrow purging using monoclonal antibodies (MoAbs) and sheep-anti-mouse immunobeads (SAM beads) prior to autologous bone marrow transplantation (ABMT) allows satisfactory tumor cell reduction without critical stem cell losses. Nevertheless, there is only a reduction but no elimination of tumor cells. The consequences will have to be clinically discussed.

Antibodies, Monoclonal↗
PubMed1992

[Effect of leukocyte depleting polyester filters on thrombocytapheresis concentrates].

We studied platelet loss, leukocyte depletion, T/B cell ratio, platelet morphology and platelet function (aggregation, hypotonic shock reaction, retention and retraction) prior to and after filtration through two different polyester filters (Sepacell PL-5A, Pall PL100) as well as the posttransfusional platelet increment 1 h after transfusion in 8 pairs of single-donor platelet concentrates (Cobe Spectra, Fresenius AS 104). Leukocyte depletion was effective (>99.9%) and platelet loss acceptable in both filters, all tests showing no indication of a diminished platelet function by filtration.

Blood Component Transfusion↗
PubMed1992

[Autologous blood donation and erythropoiesis].

Autologous blood donation before elective surgery has been widely endorsed as good transfusion practice. Although only 6% of patients undergoing elective orthopedic surgery are unable to donate 3 autologous units, 40% cannot donate 4 units because they become anemic. According to the results of our study this must be due to different problems of bone marrow dynamics, which cannot be overcome by unselected use of human recombinant erythropoietin.

Adult↗
PubMed1992

[Hemoglobin follow-up of orthopedic autologous blood transfusion patients].

Patients undergoing autologous donation prior to elective orthopedic surgery show better Hb values during the perioperative period compared to those without autologous donation, all patients in both groups receiving no homologous transfusion. The widely assumed improvement of Hb regeneration during the postoperative period according to an erythropoiesis stimulated by preoperative autologous donation is not supported by our data.

Adult↗
PubMed1992

[Acquired autoimmune hemolytic anemia after liver transplantation by "auto"-anti-A and "auto"-anti-P1].

A 47-year-old man (group A) received a cadaver liver from a group 0 donor. On day 8 after the transplant the recipient developed severe immune hemolysis and showed a positive direct antiglobulin test due to two antibodies (anti-A and anti-P1) of transplant donor origin. The possible mechanisms involved in "autoantibody" formation in the recipient are discussed.

ABO Blood-Group System↗
PubMed1992

[Examination of a Berlin blood donation branch for antibodies to hepatitis C virus with the anti-HCV test and for circulating HCV-RNA using polymerase chain reaction].

Hepatitis C virus (HCV) is responsible for the majority of cases of transfusion-related hepatitis. We performed a first-generation anti-HCV EIA in 665 repeat and 168 first-time blood donors from Berlin. 4.7 and 4.2%, respectively, showed at least one indeterminate or positive result. We further looked for HCV genome in the plasma of 20 donors with reactive anti-HCV-EIA doing a polymerase chain reaction (nested PCR). The control group consisted of 20 patients with chronic hepatitis C. The PCR was negative in all examined blood donors, but was positive in 17 of 20 controls. These findings raise the question, if a positive anti-HCV test correlates with infectiosity.

Berlin↗
PubMed1992

[Anti-M after transfusion as an indication of a genetic variant of the MN locus].

We report a case of an anti-M antibody (titer 128) and MN red blood cells (RBC) in a 76-year-old female German patient. In our case, however, RBC showed weak reactions to human anti-M compared with strong reactions using rabbit anti-M. Papain treatment destroyed the RBC reactivity to human anti-M whereas the strong reactivity to rabbit anti-M was unchanged. This pattern was also demonstrable in the patient's son and grandson. Our results indicate the existence of a rare allele at the MN locus in this family.

Aged↗