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Biomedical subjects

G Wittmann

Publications and source records attributed to G Wittmann.

At least 19 recordsLinked to original sources
PubMed2006

A novel HLA-DRB1*11 allele, DRB1*1155, was found in a patient through routine DRB1 typing using sequence-specific primers (SSP) and confirmed by allele-specific sequence-based typing.

In comparison with DRB1*1155 allele, DRB1*1103 differs at position 220/221, 'GC' is changed to 'CT', or DRB1*1125 differs at position 210/211, 'AG' is substituted with 'GA'. This results in a single amino acid exchange depending on the closest related allele investigated, whether DRB*1103 codon 74 alanine (GCG) is changed to leucine (CTG) or DRB1*1125 codon 71 arginine (GAG) is replaced with glutamic acid.

Alleles↗
PubMed2003

Differential modulation of Bordetella pertussis virulence genes as evidenced by DNA microarray analysis.

The production of most factors involved in Bordetella pertussis virulence is controlled by a two-component regulatory system termed BvgA/S. In the Bvg+ phase virulence-activated genes (vags) are expressed, and virulence-repressed genes (vrgs) are down-regulated. The expression of these genes can also be modulated by MgSO(4) or nicotinic acid. In this study we used microarrays to analyse the influence of BvgA/S or modulation on the expression of nearly 200 selected genes. With the exception of one vrg, all previously known vags and vrgs were correctly assigned as such, and the microarray analyses identified several new vags and vrgs, including genes coding for putative autotransporters, two-component systems, extracellular sigma factors, the adenylate cyclase accessory genes cyaBDE, and two genes coding for components of a type III secretion system. For most of the new vrgs and vags the results of the microarray analyses were confirmed by RT-PCR analysis and/or lacZfusions. The degree of regulation and modulation varied between genes, and showed a continuum from strongly BvgA/S-activated genes to strongly BvgA/S-repressed genes. The microarray analyses also led to the identification of a subset of vags and vrgs that are differentially regulated and modulated by MgSO(4) or nicotinic acid, indicating that these genes may be targets for multiple regulatory circuits. For example, the expression of bilA, a gene predicted to encode an intimin-like protein, was found to be activated by BvgA/S and up-modulated by nicotinic acid. Furthermore, surprisingly, in the strain analysed here, which produces only type 2 fimbriae, the fim3 gene was identified as a vrg, while fim2 was confirmed to be a vag.

Bordetella pertussis↗
PubMed2000

Arthroscopic synovectomy of the knee joint in early cases of rheumatoid arthritis: follow-up results of a multicenter study.

A retrospective multicenter study on a total of 93 knee joints in 81 patients with early forms of rheumatoid arthritis treated by arthroscopic synovectomy was carried out. During the average follow-up period of 33 months, the patients' clinical state showed appreciable improvement. The Lysholm score modified by Klein and Jensen increased from 43.2 points preoperatively to 78.1 points at follow-up. Also, the Insall score (knee score and functional score) showed a highly significant increase of 25.7 and 25.2 points to 71.2 and 80.2 points, respectively. Patients receiving additional radiation synovectomy showed a highly significantly better result than those receiving synovectomy alone. Among the individual variables investigated, pain, swelling, and walking distance in particular were improved. Only radiologically was a mild worsening observed (from Larsen stage 1.57 preoperatively to 1.95 at follow-up). The follow-up examination revealed no synovitis in 80.6% of the patients. Subjectively, 76.4% of the patients assessed the results to be good or very good, with only 7.5% remaining unsatisfied. 90.3% of the patients declared themselves in retrospect willing to undergo the operation again.

Adult↗
PubMed2000

Regional methylation of the 5' end CpG island of BRCA1 is associated with reduced gene expression in human somatic cells.

In mammalians, demethylation of specific promoter regions often correlates with gene activation; inversely, dense methylation of CpG islands leads to gene silencing, probably mediated by methyl-CpG binding proteins. In cell lines and cancers, inhibition of tissue-specific genes and tumor suppressor genes expression seems to be related to such hypermethylation. The 5' end of the breast cancer predisposition gene BRCA1 is embedded in a large CpG island of approximately 2.7 kb in length. In human sporadic breast cancers, the down-regulation of BRCA1 does not seem to be related to BRCA1 gene alterations. Southern blot analysis and the bisulfite sequencing method indicate that the BRCA1 CpG island is regionally methylated in all human tissues analyzed and unmethylated in the gametes, suggesting a role for DNA methylation in the control of gene expression. We have therefore investigated the potential role of methyl-CpG binding proteins in the regulation of BRCA1 gene expression. In vitro, partial methylation of constructs containing this region strongly inhibits gene expression in the presence of MeCP2 protein. Moreover, in the five human cell lines analyzed, chemically induced hypomethylation is associated with BRCA1 gene activation. These data suggest that methyl-CpG binding proteins might be associated with the control of BRCA1 gene expression and that methyl-DNA binding proteins may participate in the regulation of gene expression in mammalian cells.

Azacitidine↗
PubMed1999

Antibodies to private and public HLA class I epitopes in platelet recipients.

BACKGROUND: Transfusions or pregnancies can cause immunization against private HLA determinants and public epitopes shared by more than one private HLA antigen. HLA antibodies are correlated with febrile transfusion reactions, lower platelet response following platelet transfusion, and an increased rate of renal transplant rejection. Until now, antibody specificities in alloantisera from platelet recipients have been poorly characterized. STUDY DESIGN AND METHODS: Consecutive serum screens from platelet recipients were analyzed for antibodies against private HLA class I antigens and public HLA epitopes using a serum analysis program based on the 2 x 2 table analysis of correlations. Serum screens of highly immunized patients and of patients with new alloimmunization events were reviewed separately. RESULTS: Of the serum screens from 566 platelet recipients, 1577 indicated alloimmunization (panel-reactive antibodies >5%). The program assigned a specificity in 1024 of these screens (64.9%) and at least once in 522 of 566 patients (92.2%). In 267 patients, antibodies detecting public epitopes in the combined A- or B-locus cross-reacting groups were found; other public markers were detected in 39 patients. Patterns of reactivity were remarkably less stable than in patient groups previously studied. In many patients, antibodies with apparent private epitope specificity preceded the identification of antibodies against a shared marker of the same cross-reactive group. However, the disappearance of antibodies (whether or not this was followed by a new antibody against a private or public marker belonging to another cross-reacting group) was also observed. CONCLUSION: The computerized analysis of microlymphocytotoxicity tests enhances the rate of antibody specification in sera from platelet recipients with lymphocytotoxic antibodies. The identified antibodies should be taken into account in the selection of platelet donors. The data confirm and extend previous observations on HLA class I antibodies and elucidate new alloimmunization events.

Antibodies↗
PubMed1998

Changes in platelet membrane glycoproteins before bone marrow transplantation and after engraftment--a pilot study.

Thrombotic complications are observed in patients undergoing bone marrow transplantation despite thrombocytopenia and impaired coagulation due to liver function disturbances. Endothelial cell damage which is involved in the pathogenesis of major transplant related complications like graft-versus-host disease, veno-occlusive disease, sepsis or microangiopathy may be a contributing factor. Little is known about platelet function in bone marrow transplant recipients. In order to study functional alterations in circulating platelets we investigated unstimulated and ADP-stimulated platelets of 10 bone marrow transplant recipients ex vivo by flow cytometry in a pilot study using a panel of monoclonal antibodies to characterize changes in membrane glycoproteins. Samples were collected before and during conditioning and at three timepoints after engraftment. 10 healthy volunteers served as controls. Platelets of bone marrow transplant recipients showed partly a significant, higher expression of surface bound fibrinogen, activated fibrinogen receptor, and glycoprotein Ib as compared to controls. P-selectin, a marker of platelet degranulation was significantly elevated after ADP-induced stimulation at all timepoints compared to controls. Only marginal differences were found for GP IIb/IIIa surface expression. The data point to an increased platelet activation state in bone marrow transplant recipients which might contribute to the thrombotic phenomena observed in these patients.

Adenosine Diphosphate↗
PubMed1998

Tandem and triple high-dose chemotherapy with autologous stem cell rescue in metastatic breast cancer.

The purpose of this phase II study was to evaluate the therapeutic efficacy and toxicity of a tandem or triple high-dose chemotherapy (HDC) with autologous peripheral blood stem cell transplantation (PBSCT) in patients with metastatic breast cancer (MBC) as first line chemotherapy. Conventional chemotherapy consisted of two cycles of epirubicin 120 mg/m2 and ifosfamide 7500 mg/m2 in the case of tandem HDC and one cycle of paclitaxel 135 mg/m2, epirubicin 90 mg/m2 and ifosfamide 6000 mg/m2 in the case of triple HDC. Tandem HDC was composed of two cycles of epirubicin 180 mg/m2, ifosfamide 12000 mg/m2 and carboplatin 900 mg/m2. In the case of triple HDC, paclitaxel 180 mg/m2, etoposide 1500 mg/m2 and thiotepa 600 mg/m2 was added as the third cycle. Patients with tandem HDC (n = 20) were evaluable for both survival and toxicity, and patients with triple HDC (n = 21) only for toxicity because of short-term follow-up. Both tandem and triple HDC were well tolerated and could be safely administered. Non-hematological WHO grade 3 or 4 toxicities were mucositis (8), temporary renal insufficiency (1), myocardial infarction (1), and neuropathy (1). No toxic death occurred. The Kaplan-Meier estimates for 44-months without progression and the overall survival were 12% and 38% respectively. The median survival was 22 months (95% CI: 7.4-51.7 months) and the median progression-free interval 14 months (95% CI: 5.1-43.7 months). In a population with an unfavorable prognosis, tandem HDC showed similar efficacy as to that described in other phase II studies. Triple HDC seems not to improve patient outcome compared to tandem HDC, but a long-term follow up is required.

Adult↗
PubMed1998

Use of the gel agglutination technique for determination of fetomaternal hemorrhage.

BACKGROUND: Adequate administration of Rh immune globulin requires an accurate determination of the number of D-positive cells in the circulation of D-negative women. Although several tests have been described for the detection of fetomaternal hemorrhage, there is still a need for a rapid, simple, and clinically relevant screening test. STUDY DESIGN AND METHODS: Serial dilutions of a monoclonal anti-D were incubated with stock solutions (0.2 mL) of adult D-negative red cells in the absence or presence of various amounts of fetal D-positive cells (0.1, 0.2, 0.3, 0.4, and 0.5%). After incubation, the supernatants were tested against D-positive red cells by using the new, gel agglutination technique (GAT). After the GAT was adapted to detect D-positive cells at concentrations of > or = 0.2 percent, unselected postpartum samples from D-negative women (n = 420) who delivered D-positive infants were analyzed by both the new test and the Kleihauer-Betke test (KBT). RESULTS: Three of a total of 420 postpartum samples were positive (> or = 0.4% fetal cells), and 406 were negative in both tests. One had 0.5-percent fetal cells in the KBT and gave negative results in the GAT. The latter test was, however, performed after administration of Rh immune globulin. The KBT gave false-positive results in two cases, because of hereditary persistence of hemoglobin F, and the GAT gave a false-positive reaction in one case because of a maternal weak D variant. In the remaining seven cases, the KBT results were only weakly positive (0.2%) and could not be attributed solely to D positive red cells. CONCLUSION: The GAT is suited for routine screening. It provides rapid and specific detection of D-positive red cells at clinically relevant concentrations. The test may (rarely) yield false-negative results due to insufficient administration of Rh immune globulin before testing.

Adult↗
PubMed1997

Preparation of autologous bone marrow grafts for cryopreservation using the AS104 cell separator.

We evaluated the AS104 cell separator (Fresenius AG, Bad Homburg, Germany) for ex vivo processing of bone marrow (BM) grafts of 43 patients suffering from germ cell cancer (GCC, n = 22), acute lymphocytic leukemia (ALL, n = 13) and malignant lymphoma (ML, n = 8). Recoveries of total nucleated cells (TNC), mononuclear cells (MNC) and colony-forming units granulocyte-macrophage (CFU-GM) were determined in the BM concentrates prepared for cryopreservation. Hematopoietic reconstitution was analyzed in patients who underwent autologous transplantation following high-dose radio-/chemotherapy (HDRCT). Processing of the BM suspension with a median volume of 1,013 ml (range: 422-1,574) resulted in 156 ml (80-186) within 50-120 min (median: 90). In the BM concentrates, medians of 28.6% TNC (10.6-69.6), 37.9% MNC (22.3-86.4), and 52.4% CFU-GM (20.8-96.4) were recovered. Twenty-six patients underwent HDRCT with reinfusion of autologous BM and were evaluable for engraftment. They received a median of 0.8 x 10(8) MNC/kg (0.3-1.6 x 10(8)) and 2.2 x 10(4) CFU-GM/kg (0.6-12.8 x 10(4) for hematopoietic rescue. Engraftment with neutrophils > 500/microliter occurred in a median time of 12 days (8-33) in all patients. We conclude that ex vivo processing of autologous BM with median recovery rates of 37.9% for MNC, and 52.4% for CFU-GM, results in a cell population that can rescue patients from HDRCT. The described technique is convenient, time-efficient, and provides reliable results in preparing BM autografts for cryopreservation.

Adolescent↗
PubMed1997

Living epithelial-mesenchymal compounds formed in vitro suitable for autografting.

Three different, human epithelial-mesenchymal compounds (EMC) were generated in vitro for prospective grafting in epithelial defects. All compounds consisted of a fibroblast-populated collagen lattice as a mesenchymal component seeded with different types of cultured epithelial cells isolated from biopsies of healthy skin, oral mucosa and respiratory mucosa. Maturation of the epithelial cells was enabled by the presence of a high calcium concentration (1.8 mM) when cultures were lifted to the air-liquid interface. Light and electron microscopy revealed moderate differentiation of the multilayered epithelium in all compounds as well as basement membrane development at the epithelial-mesenchymal junction after 2-3 weeks. A coherent, tissue-like consistency of the collagen lattice and the presence of a basement membrane preventing detachment of the epithelium permitted easy handling and even loose suturing of the compounds produced.

Adenoids↗
PubMed1996

Diclofenac-induced immune haemolytic anaemia: simultaneous occurrence of red blood cell autoantibodies and drug-dependent antibodies.

During the last 5 years we have identified a total of 17 patients (nine females and eight males aged between 53 and 85 years) with immune haemolytic anaemia related to diclofenac (a nonsteroidal anti-inflammatory drug). All patients developed acute intravascular haemolysis. Two patients died, and eight patients developed temporary renal failure that required haemodialysis. The direct antiglobulin test was positive with anti-IgG and anti-C3d in all cases, with anti-IgA in 4/10 cases tested, and negative with anti-IgM. The indirect antiglobulin test was moderately or weakly positive in 11 cases, and IgG autoantibodies could be eluted from the red blood cells (RBCs) of all patients. Initially, the diagnosis of autoimmune haemolytic anaemia of warm type was suggested in all cases. All patients had simultaneously developed autoantibodies and drug-dependent antibodies. The majority of drug-dependent antibodies (n = 13) reacted with urine containing the drug and its metabolites (ex vivo antigen), the native drug, and diclofenac-treated RBCs. The antibodies in the remaining four cases were detectable only in the presence of ex vivo antigen. Diclofenac appears to bind only weakly to RBCs in the absence of the drug-dependent antibodies. We conclude that diclofenac forms neoantigens with RBCs that may stimulate the production of autoantibodies and drug-dependent antibodies. The resulting haemolytic syndrome is very similar to autoimmune haemolytic anaemia of warm type.

Aged↗
PubMed1996

[Prognostic significance of plasminogen activator inhibitor-1 (PAI-1) in primary breast carcinoma].

The plasminogen activator system plays a key role in the proteolysis of malignant tumours. In 155 patients with primary breast cancer levels from PAI-1 and uPA were measured in cytosol with monoclonal antibodies and by an enzyme-linked immunosorbent assay. 35 tumour tissue samples form benign breast were also examined. Malignant tumours contain higher levels of PAI-1 (8.6 ng/mg) than benign tumours (1.28 ng/mg) (p < 0.01). Also the median level of uPA was significantly higher (p < 0.01) in malignant tissue (2.38 ng/mg) in comparison to benign disease (0.54 ng/mg). No correlation was found between the proteases and the classical prognostic parameters like axillary lymph node involvement, tumour size and menopausal status. However, a significant correlation (p < 0.01) was found in tumours with lymphangiosis carcinomatosa, negative hormone receptors, grade III tumour cells and high S-phase fractions (> 5%). After a median follow-up of 46 months we found that high levels of PAI-1 correlated with short DFS (p = 0.0005) and OAS (p = 0.003). However, in the Cox multivariate regression analysis only PAI-1 was significantly independent for OAS and could therefore give additional information. We conclude that levels from PAI-1 antigen measured in cytosol of primary breast cancer is an independent prognostic parameter to identify patients with high and low risk for relapse and for individualised treatment.

Adult↗
PubMed1996

Analysis for recovery and loss of mononuclear cells and colony-forming units granulocyte-macrophage during ex vivo processing of autologous bone marrow.

During ex vivo processing of autologous bone marrow (BM) substantial loss of stem and progenitor cells should be avoided to achieve rapid and sustained hematopoietic reconstitution after high-dose radio-/chemotherapy. We processed 25 autologous BM grafts with the Fresenius AS104 cell separator for cryopreservation and we determined recoveries for mononuclear cells (MNC) and colonyforming units granulocyte-macrophage (CFU-GM) in the BM concentrates. To identify cell loss in BM fractions not cryopreserved, we investigated the MNC and CFU-GM content of BM fat and BM blood. MNC and CFU-GM recovery yielded a mean ( +/- SEM) of 42 +/- 12 and 54 +/- 20% in the BM concentrate. BM fat showed a mean loss of 7 +/- 5% for MNC and 4 +/- 3% for CFU-GM, BM blood 30 +/- 12% for MNC and 13 +/- 13% for CFU-GM, respectively. CFU-GM recovery was significantly higher in the BM concentrate of patients with hematologic malignancy (HM) compared with patients suffering from germ cell cancer (GCC): 66 +/- 21 vs. 43 +/- 12% (p < 0.02). Seventeen patients (7 GCC, 10 HM) underwent high-dose chemotherapy or radio-/chemotherapy and were autografted with 0.8 +/- 0.2 x 10(8) MNC/kg and 3.7 +/- 2.0 x 10(4) CFU-GM/kg. All patients achieved engraftment with neutrophils > 0.5 x 10(9)/l at a mean of 14 +/- 6 days. We conclude that: (1) ex vivo processing of autologous BM with a mean of recovery of 42% for MNC and 54% for CFU-GM in the BM concentrate can result in a cell population capable of sustained hematopoietic reconstitution, (2) CFU-GM recovery is significantly higher in patients with HM than in patients with GCC and (3) 37% MNC and 17% CFU-GM represent in fact cell losses recovered from BM fractions not cryopreserved (BM fat, BM blood). Furthermore, it is likely that MNC and CFU-GM not recovered from BM concentrate, BM fat and BM blood are cell losses related to the cell separator.

Adolescent↗
PubMed1996

[Expanded serologic infection testing of autologous blood donors: a report of experiences].

PURPOSE: The transmission of hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV-1/2) may cause serious disease in the recipient in cases of inadvertant homologous transfusion of autologous blood. Therefore data on the incidence of these infections in autologous blood donors are necessary. METHODS: We tested 7,438 autologous donations from 3,030 patients for anti-HIV, anti-HCV, and HBsAG. In addition, we tested all patients for antibodies to Treponema pallidum and hepatitis B virus core antigen (anti-HBc) and for elevated serum ALT levels. Confirmation tests were performed only for positive anti-HIV-EIAs. RESULTS: The frequencies of anti-HIV, anti-HCV, and HBsAG were 0.05, 2.8 and 0.6% of all units. The rate of anti-HCV decreased from 4.0 to 3.4% after introduction of a 2nd generation EIA but was only 0.6% using a 3rd generation EIA. Anti-HBc was positive in 9.4%, the TPHA test in 0.5%. ALT was above 45 U/I in 1.2%, but outside the sex related normal range in 8.4% of all units. 23.7% of all donations positive for anti-HIV, anti-HCV, or HBsAG showed at least one pathologic surrogate test; 7.5% of all surrogate marker positive units contained anti-HIV, anti-HCV, or HBsAG. DISCUSSION: The overall frequency of anti-HIV, anti-HCV, and HBsAG was only 3.45% of all autologous donations and was reduced further after introduction of 2nd and 3rd generation anti-HCV-EIAs. However, the rate of surrogate marker positive units was 10.9%. The overlap between both groups was remarkable. We conclude from our data that procedures to minimize the risk of inadvertant homologous transfusion of autologous blood are necessary despite the implementation of screening tests in autologous donation programs.

Adolescent↗
PubMed1995

[Prognostic relevance of hepatitis C virus genotype for responsiveness to interferon-alpha].

The influence of hepatitis C virus (HCV)-genotypes on the responsiveness to interferon- (IFN-alpha) was studied in 116 patients with proven chronic hepatitis C. 88 of 116 (76%) patients were infected with HCV-genotype 1, 7 (6%) with HCV-genotype 2, and 21 patients (18%) with HCV-genotype 3. All patients received at least 3 MU recombinant IFN-alpha-2a, 2b or lymphoblastoid IFN-alpha tiw for at least 6 month (total IFN-alpha dose per patient 216-720 MU, mean 360; treatment duration 6-12 month, mean 8). The follow-up after cessation of therapy was 9-48 months (mean 25). Sustained normalization of the aminotransferase levels was observed in 20 (17%) of the 116 patients. 10 of the 88 (11%) patients with HCV-genotype 1, 7 of the 21 (33%) patients with HCV-genotype 3 (p < 0.02), and 3 out of the 7 patients with HCV-genotype-2- infection achieved a sustained remission. No response was observed in 58 (66%) and 3 (14%) patients with HCV-genotype 1 and 3 infections, respectively (p < 0.002). All but one of the sustained responders remained HCV-RNA negative during the entire follow-up. There were no significant differences between the sustained responders and the group of non-responders and responders with relapse in relation to age, pretreatment aminotransferase levels, histological activity index, or given IFN-alpha dosage. HCV-genotyping is helpful in evaluating the responsiveness to IFN-alpha and will be of importance considering the indication of therapy.

Adult↗