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T Zeiler

Publications and source records attributed to T Zeiler.

At least 37 records · Page 2Linked to original sources
PubMed1997

Recombinant allergen fragments as candidate preparations for allergen immunotherapy.

BACKGROUND: Lately, renewed interest has arisen in the new forms of allergen immunotherapy because they may offer alternatives for drug treatment. OBJECTIVE: The purpose of this study was to develop a well-characterized preparation of the main respiratory cow dander allergen, Bos d 2, with attenuated allergenic activity. METHODS: The immunologic characteristics of Bos d 2 preparations were studied by indirect IgE ELISA, ELISA inhibition, Western blotting, histamine release, skin prick tests, and the proliferation tests of allergen-specific T-cell clones. RESULTS: The complete recombinant Bos d 2 was observed to bind effectively, IgE of cow-allergic patients in indirect ELISA. In other experiments, the IgE-binding capacity of recombinant Bos d 2 proved to be lower compared with native Bos d 2. When the two overlapping recombinant fragments of Bos d 2 (corresponding amino acids 1-131 and 81-172, respectively) covering the whole molecule were compared with the complete recombinant Bos d 2 with several methods, only a low level of residual reactivity was observed. For example, recombinant fragments could not bind antibody at all in ELISA inhibition tests retaining, however, some reactivity in skin prick tests. In contrast, the fragments were able to stimulate vigorously Bos d 2-specific T-cell clones. CONCLUSION: The approach we have taken may offer a simple and reproducible way to produce hypoallergenic preparations for immunotherapy, circumventing simultaneously some of the problems of other experimental methods such as individual T-cell epitope recognition in peptide-based immunotherapy.

Adult↗
PubMed1997

[In-line leukocyte depletion ov thrombocytapheresis concentrates with the Fresenius-AS-104 cell separator].

UNLABELLED: This study reports on in-line filtration of 72 platelet concentrates (PC) collected by the Fresenius AS 104 cell separator, using the new C4F sets with integrated leukocyte filters (Biofil P plus). MATERIAL AND METHODS: 72 volunteer donors, automatic counts of platelets, microscopical counting of residual leukocytes with the Nageotte chamber, GMP-140 by flow cytometrie, beta-thromboglobulin release, platelet aggregation (ADP, collagen). RESULTS AND CONCLUSION: Filtration reduced leukocytes by 98.5%. Residual leukocyte contamination remained clearly below 5 x 10(6) (mean 0.5 +/- 0.6 x 10(6), maximum 2.8 x 10(6). Platelet loss by filtration was found to be between 27.4 and 0.7% (median 8.5%). Filtration caused a significant decrease of platelet aggregability (p < 0.005), but no significant increase of beta-thromboglobulin release and only a slight decrease of GMP-140 expression. From these data can be concluded that in-line filtration was highly efficient with acceptable platelet retention. No significant platelet activation could be observed in the PC. The decrease of platelet aggregability have been due to the reduction of activated platelets which are believed to show reduced in vivo survival.

Cell Separation↗
PubMed1997

[A new separation protocol (DRBCP-F) for automated blood component donation with the MCS 3p cell separator for collection of leukocyte depleted erythrocyte concentrates and plasma].

Previously published studies on automated blood component donation with the MCS 3p cell separator proved fairly good quality of the collected red blood cells (RBC) and fresh frozen plasma (FFP), with the disadvantage of a low hematocrit of the filtered RBC and a high platelet contamination of the FFP (RBCP-F protocol.) The DRBCP-F protocol was designed to eliminate the above-mentioned disadvantages and to provide 1 unit of leuko-depleted (filtered) RBC, 2 units of FFP, and additionally 1 platelet concentrate (PC) from the buffy coat. Twenty automated blood component collections (2 cycles, Latham bowl at 5,500 rpm, 230 ml isotonic saline for volume balance, PAGGS-M as additive solution) were performed. The RBC were filtered in a closed system after storage at 4 degrees C for 24 h. Blood cell counts and biochemical parameters of the RBC were determined initially and after 49 days. PC were separated from buffy coat after a soft spin. The volume of the RBC amounted to 293 +/- 12 ml (mean +/- SD) with a hematocrit of 0.61 +/- 0.05 l/l. Residual leukocytes after filtration were found to be 0.04 x 10(6) +/- 0.06 per unit. After storage, the following data were obtained: hemolysis 0.38%, ATP 2.1 +/- 0.4 mumol/g Hb, 2,3-diphosphoglycerate (2,3-DPG) 1.4 +/- 0.3 mumol/g Hb, ph 6.3 +/- 0.1, potassium 6.4 mmol per unit, and LDH in the supernatant was 219 U/l. None of the RBC showed bacterial growth after 49 days. The volume of the collected FFP was 398 +/- 32 ml, with 3.4 +/- 3.5 x 10(3) residual platelets and 5 +/- 12 leukocytes per microliter. Platelet concentrates contained 90.2 +/- 32 x 10(9) platelets in 88 +/- 14 ml plasma. Automated blood donation with the DRBCP-F protocol provided RBC with very low residual leukocyte counts, adequate hematocrit and good metabolic status up to 49 days, and FFP with low platelet contamination. The platelet concentrates were even superior to those prepared from whole blood using the buffy coat method. The storable leuko-depleted RBC are suitable for transfusion of chronically transfused patients in whom primary HLA sensitization should be prevented.

Adult↗
PubMed1996

Complementary DNA cloning of the predominant allergen of bovine dander: a new member in the lipocalin family.

BACKGROUND: A number of allergenic proteins in animal danders have been characterized at the molecular level, but little is known of their biologic functions. We have found that the prevalence of IgE antibodies among patients with cattle-associated asthma is highest against a dander protein referred to as BDA20. OBJECTIVE: The study was performed to characterize the molecular structure of BDA20,* the predominant allergen in bovine dander. METHODS: Clones encoding allergens were identified and isolated from a complementary DNA library by immunoblotting and DNA hybridization and sequenced. Recombinant proteins were produced in Escherichia coli. Immunoreactivity of the recombinant proteins and amino acid sequences of peptides obtained from native BDA20 after Lys-C cleavage were used to identify clones coding for BDA20. RESULTS: In this article we report the cDNA and amino acid sequences of BDA20. Homology comparisons showed that BDA20 belongs to the family of lipocalins. CONCLUSIONS: The results link a dander allergen to a group of functionally important proteins. Lipocalins are present in various body fluids and secretions of several animal species in which they function as carriers of small hydrophobic molecules, such as retinoids and pheromones. If allergenicity proves to be a property shared by lipocalins, our results will have considerable implications for allergen research.

Allergens↗
PubMed1996

Immune reactivity of cow-asthmatic dairy farmers to the major allergen of cow (BDA20) and to other cow-derived proteins. The use of purified BDA20 increases the performance of diagnostic tests in respiratory cow allergy.

BACKGROUND: Cow dust is one of the most important inducers of occupational allergic diseases in Finland. For example, in 1991 it accounted for almost 40% of the new occupational asthma cases. OBJECTIVE: This study compares the performance of the purified major cow allergen (BDA20) and crude bovine epithelial extract (BEA) in diagnostic tests and examines the role of milk allergy-associated bovine proteins (bovine serum albumin, alpha-lactalbumin, beta-lactoglobulin, casein) in respiratory cow allergy. METHODS: The humoral responses of cow-asthmatic and healthy farmers to the various components of BEA were analysed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The levels of specific IgE and IgG antibodies were quantificated with enzyme-linked immunosorbent assays (ELISAs). The cellular responses were analysed with antigen-specific lymphocyte proliferation tests. RESULTS: The specific anti-BDA20 IgE measurement was found to be best in distinguishing between the asthmatic farmers and their healthy colleagues. It proved possible to determine a cut-off value that gave the analysis a specificity and sensitivity of 100%; the distinction between the two groups was highly significant (P < 0.0001). In the lymphocyte proliferation analysis, cow asthma was more closely associated with reactivity to BDA20 than to BEA. In the measurement of anti-BDA20 and anti-BEA IgG antibody levels, considerable overlap between the groups was observed, suggesting that these antibodies are not directly involved in cow allergy. When proteins associated with milk allergy were used as test reagents, no statistically significant differences could be observed between the groups, except for anti-casein IgE antibodies the level of which, however, overlapped considerably between the farmer groups. CONCLUSION: These findings suggest that purified BDA20 is better than BEA for diagnosing cow asthma and that proteins associated with milk allergy are of only marginal significance in this disease.

Adult↗
PubMed1996

[Automated blood component collection with the MCS 3p].

OBJECTIVE: Two new protocols for the MCS 3p cellseparator (Haemonetics) for automated collection of blood components were evaluated. MATERIAL AND METHODS: Two units of FFP and one unit of buffy coat free red blood cells (RBC) in additive solution (PAGGS-M) were produced with the D-RBCP protocol. The RBCP-F protocol included additional in-line filtration of the RBC in a closed system. 20 automated blood component collections were performed with each of the two programs. Filtration of the RBC was performed after storage for 24 h at 4 degrees C. Blood cell counts, biochemical characterization of the RBCs (ATP, 2,3-DPG, LDH, HBDH, free Hb, K+, pH) were determined on day 0, 1, 14, 28 and 49. RESULTS AND CONCLUSIONS: Erythroplasmapheresis with both protocols was performed without any technical problems or adverse reactions. The biochemical parameters of the RBC (until 49 days) were as good or even better as with standard preparations (Hb, 2,3-DPG, ATP, LDH, HBDH, hemolysis, K+). Leukocyte and platelet counts in RBC and FFP (D-RBCP) were well within the range requested by German guidelines. Leukocyte reduction of RBC in RBCP-F was adequate but platelets in FFP exceeded the standard values. The extracorporal volume (771 ml in D-RBCP and 632 ml in RBCP-F) was rather large and at least should be adaptable to the donor's individual blood volume.

Blood Banks↗
PubMed1996

[Solid phase technique versus gel centrifugation for detection of erythrocyte antibodies--a prospective study comparison the 2 antibody detection tests].

AIM: To define differences of specifity and sensitivity between a solid phase- and a gel centrifugation test for detection of irregular erythrocyte antibodies. STUDY DESIGN: 3052 blood samples were screened for erythrocyte antibodies (AB) by gel centrifugation [ID-System, (ID) 37 degrees C Bromelin and indirect antiglobulin test with LISS (IAT)] and a solid phase antiglobulin test [Capture-R Ready Screen (CR)] in a prospective study. Identical test cells were used as immobilized monolayer in CR and as 1%-suspension in ID. Additionally, 42 sera with antibodies reacting in both tests were titered geometrically in both techniques. RESULTS: In 79 (2.6%) of all sera tested, irregular erythrocyte antibodies were detected. 64 (81%) of these positive sera were detected by both tests, 73 (92.3%) by ID and 70 (88.4%) by CR. 6 sera with AB (7.6%) were positive only with CR (1 Ce, 1 E, 1 Leb, 1 C, 1 D, 1 Cob) and 9 (11.4%) only with ID (4 Lea, 1 Fya, 1 C, 2 P1, 1 D). Seven AB solely detected in ID only reacted in the bromelin test, besides an anti-Fya, which was an IgM antibody. The titration of IgG antibodies showed a slightly higher sensitivity of the CR (less than one titre step). The ID showed clearly more unspecific reactions (1.1%) than the CR (0.5%). DISCUSSION: The antibody screening with the ID proved to detect more AB than the CR (mainly due to certainly irrelevant "enzyme only" AB). On the other hand, relevant IgG AB were detected more sensitive by the CR. Unspecific reactions appeared clearly more often in ID, predominantly when using the bromelin test. Missing a strong IgM anti-Fya in the CR is certainly a concern because of its assumed haemolytic activity. Therefore CR for antibody screening should always be combined with a method for crossmatching that safely detects IgM antibodies which are relevant for transfusion.

Blood Group Antigens↗
PubMed1995

[Survey of blood donors on the topic of "reimbursement for blood donors"].

BACKGROUND: Remuneration for blood donors, in the way as presently handled by governmental and communal blood transfusion services in Germany, is not generally accepted. It is feared that donors are recruited with increased risk to transmit infectious diseases, especially AIDS. Alternative incentives are discussed. After the so-called AIDS scandal in Germany, a change in the donor motivation was to be expected, associated with an increased willingness to renounce remuneration. Therefore, we performed the present survey, in which we evaluated the donor's willingness to renounce remuneration, possibilities of cashless remuneration and other alternative incentives. MATERIAL AND METHODS: During March and April 1994, a total of 1,157 blood donors of the University Blood Bank Marburg were questioned anonymously by a questionnaire in the framework of whole-blood donations. Beside the above-mentioned aspects demoscopic data were included (age, sex, profession, journey). RESULTS: Cutting of remuneration without any other compensation was refused by 86.1% of the donors, 77% would not want to further donate blood in this case. Transfer of money to a bank account instead of cash payment was accepted by 78.6%, the use of non-negotiable cheques by 68.7%. Alternative compensation by tickets for theater, concert, cinema or coupons for restaurants met with the approval of only 27.3%; under these circumstances, 36.9% would be willing to continue blood donation. With increasing age and number of donations, but largely independent of social status, donors attached greater importance to retention of remuneration. DISCUSSION: Cutting of remuneration would result in a considerable reduction of the willingness to donate blood within the population of donors of the governmental and communal blood transfusion services. However, an increase of virus safety of the blood products would not be reached in this way, since especially the long-term donors would be driven away. Considerable bottlenecks, particularly in the specific blood supply of hospital-integrated blood transfusion services, would have to be expected.

Adolescent↗
PubMed1994

The effect of methylene blue phototreatment on plasma proteins and in vitro coagulation capability of single-donor fresh-frozen plasma.

BACKGROUND: Photodynamic virus inactivation of fresh-frozen plasma (FFP) may result in its impaired coagulation capability. STUDY DESIGN AND METHODS: Double-volume plasmapheresis samples from 11 donors were divided in pairs of 250 mL. One group underwent methylene blue (MB) phototreatment (MB-FFP). The other group was treated according to the standards of the American Association of Blood Banks for preparation and storage of FFP. Parameters of hemostasis and clinically important plasma proteins were tested in native plasma, thawed MB-FFP, thawed FFP, and twice-frozen and thawed FFP (FFP-II). RESULTS: Mean activities of factor V (73.4 vs. 94.5%; p < 0.01), factor VIII (58.1 vs. 86.7%; p < 0.001), and fibrinogen (1.8 vs. 2.8 g/L; p < 0.001) were reduced in MB-FFP as compared to those in FFP. The comparison of MB-FFP to FFP-II revealed reduced activities of factor VIII (58.1 vs. 85.2%; p < 0.001) and fibrinogen (1.8 vs. 2.8 g/L; p < 0.001) but no changes in factor V. Activated partial thromboplastin time in MB-FFP was prolonged beyond the upper normal range (+5.3 sec; p < 0.001) and prothrombin time increased in MB-FFP versus FFP (+0.96 sec; p < 0.001). CONCLUSION: MB phototreatment reduces the in vitro coagulation capacity of FFP, most likely as a result of the effects of an additional freezing and thawing procedure and photooxidation-induced protein damage.

Blood Coagulation↗
PubMed1994

Identification of antibodies toward private and public class I HLA epitopes in sensitized patients.

BACKGROUND: Antibodies to HLA determinants may decrease the increment after platelet transfusion and are correlated with increased rates of rejection in renal transplantation. Cross-match tests and HLA antibody specification are used to identify compatible donors for sensitized patients. However, search for cross-match negative donors may be ineffective, and many sera containing antibodies toward public HLA epitopes give no clear results in conventional specificity analysis. MATERIALS AND METHODS: We tested a series of 4,625 sera from 1,073 patients with hematological, malignant or other diseases using a fluorescence lymphocytotoxicity test (LCT). We applied an evaluation program incorporating a list of public antigens belonging to known cross-reacting groups (CREGs) to detect antibodies toward private and just as well public epitopes. RESULTS: In 694 sera (15.0%) from 240 patients the panel reactivity (PRA) in LCT assay was higher than 5%. PRA was > or = 50% in 258 (37.2%) and < 50% in 436 sera (62.8%). In both groups we identified specific antibodies toward public HLA class I epitopes. Overall antibody specification was successful in 429 of 694 sera (61.8%) and in 175 of 240 patients (72.9%), respectively. The rate of antibodies against public epitopes shared by more than one HLA class I gene product was 203/694 (29.3%) with respect to tested sera and 83/240 (34.5%) with respect to patients. The rate of public epitope antibodies was highest in sera with PRA values from 30 to 90% showing public epitope specificity in 159 of 353 sera (45.0%). CONCLUSIONS: We conclude that antibodies toward public HLA class I determinants are detectable not only in highly sensitized patients. The described program may increase the rate of antibody specification and facilitate the platelet supply in platelet refractory patients.

Blood Grouping and Crossmatching↗
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

[18 months experience with a new single needle cytapheresis system (Fresenius AS 104 SN)].

BACKGROUND: Since October 1991 the third-generation cell separator Fresenius AS 104 offers a single-needle (SN) option for thrombocytapheresis. Here we present our first 18-month experience with this new single-needle system. MATERIALS AND METHODS: We performed 395 thrombocytaphereses in 225 donors. The influence of blood flow, cycle volume, and interface position on efficacy and leukocyte contamination was evaluated. RESULTS: 395 thrombocytaphereses were performed with an average thrombocyte yield of 3.00 +/- 0.69 x 10(11) platelets and a leukocyte contamination of 1.66 +/- 3.1 x 10(8) per concentrate. Blood flow rates of 50 ml/min (vs. 60 ml/min) and an interface position of 6:2 (vs. 7:1) resulted in a lower leukocyte contamination, but without statistical significance. CONCLUSION: The SN program of the AS 104 provides high thrombocyte yields and less leukocyte contamination than other SN systems, but 77% of the concentrates still contain more than 0.5 x 10(8) leukocytes.

Adult↗
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↗