PubMed Health⌕ Search

Biomedical subjects

P Wernet

Publications and source records attributed to P Wernet.

At least 19 recordsLinked to original sources
PubMed2006

Intracoronary autologous bone marrow cell transplantation beneficially modulates heart rate variability.

The effect of intracoronary administration of autologous bone marrow cells on autonomic modulation of heart rate has not yet been demonstrated. Therefore, we investigated different parameters of heart rate variability (HRV) in 46 patients without (n=23) or with (n=23) intracoronary stem cell therapy after transmural myocardial infarction. After three to twelve months of follow up, patients receiving stem cells showed a significant increase of HRV parameters that have been linked to cardiovascular prognosis.

Aged↗
PubMed2006

[Intra-arterial and intramuscular transplantation of adult, autologous bone marrow stem cells. Novel treatment for therapy-refractory peripheral arterial occlusive disease].

HISTORY AND CLINICAL FINDINGS: A 62-year-old man had limb ischemia in stage IIb (Fontaine's classification). After surgical and interventional measures the right superficial femoral artery had remained occluded for more than one year. The patient's walking distance was only 100 meters. It was therefore decided to do a combined intraarterial and intramuscular transplantation of stem cells into the right limb. INVESTIGATIONS: Before and 10 weeks after the transplantation noninvasive tests, namely walking distance, ankle-brachial index at rest and during exercise, occlusion plethysmography and capillary venous oxygen saturation were measured. The patient was also asked to fill in a questionnaire of his symptoms. THERAPY AND RESULTS: After harvesting the patient's bone marrow the mononuclear cell fraction was separated (109.8 x 10(6)). Afterwards 10 ml of the cell suspension were injected into the right superficial femoral artery and 5 ml each of the suspension was injected into 5 different locations of the quadriceps femoris and the gastrocnemius muscles. After 10 weeks" follow-up a seven-fold improvement of walking distance and an increase of tissue oxygen saturation of more then 50% were recorded. The ankle-brachial index at rest remained unchanged, but on exercise it increased by 24%. CONCLUSION: The combined intraarterial and intramuscular transplantation of human autologous bone marrow stem cells may be a novel and clinically feasible treatment for patients with severe chronic limb ischemia. The success of this approach may be the result of increased neo-angiogenesis, especially of the small muscle-supplying vessels.

Arterial Occlusive Diseases↗
PubMed2005

High-resolution HLA typing by sequencing for HLA-A, -B, -C, -DR, -DQ in 122 unrelated cord blood/patient pair transplants hardly improves long-term clinical outcome.

To determine the impact of high-resolution (HR) HLA typing with outcomes after UCBT, DNAs of 122 pairs were analysed for HLA class I and class II mismatches (MM) based on HR typing. For HLA-A, -B on low-resolution typing and -DRB1 on HR typing, the following MM situation resulted: no MM (13%), one MM (40%), two MM (36%), three MM (8%), four MM (3%). For A, B, C, DR and DQ based on HR typing the following MM occurred: No MM (4%), one MM (10%), two MM (15%), three MM (22%), four MM (25%), five MM (12%), six MM (6%), seven MM (3%), eight MM (2%). There was no significant association between number of MM (HR) for both HLA-A, -B and -DRB1 and HLA-A, -B, -C, -DRB1 and DQB1 and aGvHD grade II-IV. There was a trend that MM in class I HR were associated with neutrophil recovery; HLA-A locus typing analysed in HvG direction was associated with reduced cumulative incidence of engraftment (P=0.04), the same for C-KIR in HvG direction (P=0.01). No significant correlation was found between numbers of HLA-MM on the HR level with 2-year survival. The analysis shows that the degree of mismatching in UCBT is even higher than expected.

ABO Blood-Group System↗
PubMed2004

[In vivo and in vitro bone regeneration from cord blood derived mesenchymal stem cells].

BACKGROUND: Mesenchymal stem cells with an osteoblastic differentiating potency are investigated in regard of probable tissue engineering for further clinical application. The following report describes the use of cord blood derived stem cells as an alternative to other stem cell populations for bone regenerating tissue engineering. METHODS: To demonstrate the multipotency of cord blood derived mesenchymal stem cells, unrestringated somatic stem cells (USSC) were isolated from cord blood and underwent an osteo-, chondro- and adipoblastic in vitro stimulation. To evaluate the osteoinductive potency of a porcine collagen I/III cell carrier USSC were incubated on this matrix. To investigate the in vivo effects of human USSC an athymic rat model was developed. These cells were transplanted into a femoral defect. RESULTS: Cord blood derived mesenchymal stem cells (USSC) have an in vitro multipotency and show adipo-, chondro- and osteogenic differentiation. The porcine collagen I/III carrier promoted an osteoblastic differentiation. USSC survived after xenotransplantation in an athymic rat and differentiated into osteoblasts filling the bony defect zone. CONCLUSION: Human USSC are a mesenchymal multipotent stem cell population that shows osteoblastic differentiation onto a collagen I/III carrier in vitro as well as in an athymic rat in vivo.

Adipocytes↗
PubMed2004

[Long-term results of homologous penetrating limbokeratoplasty in total limbal stem cell insufficiency after chemical/thermal burns].

BACKGROUND: Since 1991 homologous penetrating limbokeratoplasty has been performed in 32 patients with severe limbal stem cell insufficiency following chemical/thermal burns. The long-term results considering the effects of HLA matching are presented for the first time. PATIENTS: All patients received systemic cyclosporin A and/or mycophenolate mofetil in the postoperative course. In 9 patients grafts with 0-1 HLA mismatches in the HLA A, B and DR loci, in 6 patients grafts with 2-6 mismatches and in 17 patients untyped grafts were used. Long-term clear graft survival was estimated according to Kaplan and Meier. RESULTS: Five years postoperatively, 50% of the grafts with 0-1 mismatches, 32% of the grafts with 2-6 mismatches and 18% of the untyped grafts were centrally clear (log-rank-test, p>0.05). CONCLUSIONS: Although statistically not significant, HLA matched grafts seem to deliver better results than untyped grafts in penetrating limbokeratoplasty. Improvement of matching strategies and immunosuppression may possibly further improve current results.

Actuarial Analysis↗
PubMed2004

Hematopoietic stem cell donor registry strategies for assigning search determinants and matching relationships.

Registries and cord blood banks around the world collect and store the HLA types of volunteers in order to identify matched unrelated donors for patients requiring hematopoietic stem cell transplantation. This task is complicated by the many formats in which HLA types are provided by the testing laboratories (types obtained by serology vs by DNA-based methods; high vs intermediate vs low resolution) and by the need to identify which of these diverse types are most likely to match the HLA assignments of a searching patient as closely as possible. Conversion of the assignments to 'search determinants' may be included within the algorithm used to select and prioritize a list of potentially suitable donors, either as an aid to matching or as a tool to optimize the performance of comparisons within large data files. The strategies used by registries to create search determinants are described. A set of search determinants, utilized by the National Marrow Donor Program, is provided as an example and is intended to initiate further discussion aimed at understanding the process used by each registry with the possibility of developing a standard process among registries worldwide.

Algorithms↗
PubMed2004

Improvement of graft prognosis in penetrating normal-risk keratoplasty by HLA class I and II matching.

BACKGROUND: Owing to contradictory results, HLA matching in penetrating keratoplasty still is equivocal. Different surgical techniques in multicentre studies, missing risk differentiation in high-risk situations, and faulty HLA typing can be identified as main reasons for these contradictory results. In this monocentre study, the value of HLA class I and II matching (A, B, DR loci) was examined in a homogeneous group of 418 normal-risk keratoplasty patients using serological typing techniques for HLA class I and immunogenetic typing techniques for class II. METHODS: Penetrating normal-risk keratoplasty was performed in two groups of patients (group I with 0-2, group II with 3-6 mismatches in the A/B/DR loci). All surgery was carried out by three experienced surgeons according to a standardized scheme. Furthermore, postoperative therapy and controls were standardized. There were no statistically significant differences between the two study groups with regard to the number of ABO or H-Y compatibilities, patient age, patient gender, ratio of previous intraocular surgery, ratio of triple procedures, indication for surgery, follow-up period, donor age, donor gender, post-mortem time of the graft, and endothelial cell density of the graft at the end of organ culture. All HLA typing was performed in a quality-controlled laboratory, serologically for HLA class I (A and B loci) and immunogenetically for HLA class II (DR locus). RESULTS: At 4 years postoperatively, the ratio of clear and rejection-free graft survival was 92% in group I and 66% in group II (Kaplan-Meier estimation, log rank test, P=0.03). Monovariate analysis in the Cox model gave no influence of solitary HLA class I or II matching, but only an influence of combined HLA class I and II matching (P=0.03). CONCLUSIONS: In this monocentre study with proper typing techniques, the beneficial effect of HLA class I plus II matching on clear and rejection-free graft survival could be demonstrated in a homogeneous group of normal-risk keratoplasty patients.

ABO Blood-Group System↗
PubMed2001

[Intracoronary, human autologous stem cell transplantation for myocardial regeneration following myocardial infarction].

OBJECTIVE: The regenerative potential of human autologous adult stem cells on myocardial regeneration and neovascularisation after myocardial infarction may contribute to healing of the infarction area. But no clinical application has previously been reported. We here describe for the first time the results of this method applied in a patient who had sustained an acute myocardial infarction. HISTORY AND CLINICAL FINDINGS: 14 hours after the onset of left precordial pain a 46-year-old man was admitted to our hospital for interventional diagnosis and treatment. Coronary angiography demonstrated occlusion of the anterior descending branch of the left coronary artery with transmural infarction. This was treated by percutaneous transluminal catheter angioplasty and stent placement. THERAPY AND RESULTS: Mononuclear bone marrow cells of the patient were prepared and 6 days after infaction 1,2 infinity 107 cells were transplanted at low pressure via a percutaneous transluminal catheter placed in the infarct-related artery. Before and 10 weeks after this procedure left ventricular function, infarct size, ventricular geometry and myocardial perfusion were measured by (201)thallium SPECT both at rest and on exercise, together with bull's-eye analysis, dobutamine stress echocardiography, right heart catheterisation and radionuclide ventriculography. At 10 weeks after the stem cell transplantation the transmural infarct area had been reduced from 24.6 % to 15.7 % of left ventricular circumference, while ejection fraction, cardiac index and stroke volume had increased by 20-30 %. On exercise the end diastolic volume had decreased by 30 % and there was a comparable fall in left ventricular filling pressure (mean pulmonary capillary pressure). CONCLUSION: These results for the first time demonstrate that selective intracoronary transplantation of human autologous adult stem cells is possible under clinical conditions and that it can lead to regeneration of the myocardial scar after transmural infarction. The therapeutic effects may be ascribed to stem cell-associated myocardial regeneration and neovascularisation.

Angioplasty, Balloon, Coronary↗
PubMed2001

Comparison of outcomes of unrelated bone marrow and umbilical cord blood transplants in children with acute leukemia.

In order to compare the outcomes of unrelated umbilical cord blood transplants (UCBTs) or bone marrow transplants, 541 children with acute leukemia (AL) transplanted with umbilical cord blood (n = 99), T-cell-depleted unrelated bone marrow transplants (T-UBMT) (n = 180), or nonmanipulated (UBMT) (n = 262), were analyzed in a retrospective multicenter study. Comparisons were performed after adjustment for patient, disease, and transplant variables. The major difference between the 3 groups was the higher number in the UCBT group of HLA mismatches (defined by serology for class I and molecular typing for DRB1). The donor was HLA mismatched in 92% of UCBTs, in 18% of UBMTs, and in 43% of T-UBMTs (P <.001). Other significant differences were observed in pretransplant disease characteristics, preparative regimens, graft-versus-host disease (GVHD) prophylaxis, and number of cells infused. Nonadjusted estimates of 2-year survival and event-free survival rates were 49% and 43%, respectively, in the UBMT group, 41% and 37% in the T-UBMT group, and 35% and 31% in the UCBT group. After adjustment, differences in outcomes appeared in the first 100 days after the transplantation. Compared with UBMT recipients, UCBT recipients had delayed hematopoietic recovery (Hazard ratio [HR] = 0.37; 95% confidence interval [95CI]: 0.27-0.52; P <.001), increased 100 day transplant-related mortality (HR = 2.13; 95CI: 1.20-3.76; P <.01) and decreased acute graft-versus-host disease (aGVHD) (HR = 0.50; 95CI: 0.34-0.73; P <.001). T-UBMT recipients had decreased aGVHD (HR = 0.25; 95CI: 0.17-0.36; P <.0001) and increased risk of relapse (HR = 1.96; 95CI: 1.11-3.45; P =.02). After day 100 posttransplant, the 3 groups achieved similar results in terms of relapse. Chronic GVHD was decreased after T-UBMT (HR = 0.21; 95CI: 0.11-0.37; P <.0001) and UCBT (HR = 0.24; 95CI: 0.01-0.66; P =.002), and overall mortality was higher in T-UBMT recipients (HR = 1.39; 95CI: 0.97-1.99; P <.07). In conclusion, the use of UCBT, as a source of hematopoietic stem cells, is a reasonable option for children with AL lacking an acceptably matched unrelated marrow donor.

Analysis of Variance↗
PubMed2001

Phenotypic and functional comparison of monocytes from cord blood and granulocyte colony-stimulating factor-mobilized apheresis products.

OBJECTIVE: It is well established that T cells are effector cells in graft-vs-host disease (GVHD), yet the contribution of graft monocytes is less well characterized. Therefore, monocytes in cord blood (CB) and granulocyte colony-stimulating factor-mobilized apheresis products (G-AP), two stem cell grafts associated with reduction of acute and chronic GVHD and relative reduction of acute GVHD, respectively, were compared phenotypically and functionally. MATERIALS AND METHODS: The frequencies, phenotypes, and pinocytosis activities of monocytes from CB and G-AP were determined by flow cytometry and their allostimulatory potential in a primary mixed leukocyte reaction. RESULTS: G-AP contained significantly more monocytes than CB (24.9% +/- 7.1% vs 8.8% +/- 1.5% CD14+ and 62.4 +/- 27.5 x 10(6) vs 0.9 +/- 0.2 x 10(6) CD14+ cells/mL). Monocytes from both sources revealed similar phenotypes. They expressed CD4, CD11a, CD11b, CD11c, CD18, CD32, CD33, CD45R0, CD48, CD50, CD54, CD58, CD64, CD86, CD102, CD116, CD123, and HLA-DR; showed no expression of CD1a and CD83; and weak expression of CD16, CD45RA, and CD80. The levels of CD80 and CD86 expression were comparable; however, in contrast to G-AP monocytes, CB monocytes lacked CD40. There was no difference in pinocytosis activity and allostimulatory capacity of CB and G-AP monocytes. CONCLUSIONS: Monocytes in CB and G-AP are phenotypically and functionally comparable. The only difference observed is the lack of CD40 on CB monocytes.

Antigen Presentation↗
PubMed2001

Factors affecting lymphocyte subset reconstitution after either related or unrelated cord blood transplantation in children -- a Eurocord analysis.

Immune recovery after cord blood transplantation (CBT) is of concern owing to the low number of lymphocytes transferred with the graft and their immaturity. Risk factors influencing lymphocyte subset reconstitution related to disease, patient, donor and transplant were studied in 63 children (< 16 years), given either related (n = 14) or unrelated (n = 49) CBT for malignant (n = 33) or non-malignant diseases (n = 30). Only children with sustained myeloid engraftment were analysed. Absolute numbers of T (CD3(+), CD4(+), CD8(+)), B and natural killer (NK) cells were reported 2--3, 6, 9, 12 and 12--24 months after CBT. Median patient age was 4.0 years (0--15) and median follow-up was 23 months (1.7--61.0). Twenty-six patients received human leucocyte antigen (HLA)-matched CBT and 37 received HLA-mismatched CBT. The median number of nucleated cells (NCs) collected/recipient weight was 6.1 x 10(7)/kg. In this selected population, the estimate 2 year survival was 85%. Lymphocyte reconstitution (defined as the median time to reach the normal value of age-matched healthy children) was 3, 6 and 8 months for NK, B and CD8(+) cells, while it was 11.7 months for both CD3(+) and CD4(+) lymphocytes. In the multivariate analysis, factors favouring T-cell recovery were: related donor (P = 0.002); higher NCs/kg (P = 0.005) and recipient cytomegalovirus (CMV)-positive serology (P = 0.04). Presence of acute graft-versus-host disease (GVHD) delayed T-cell recovery (P = 0.04). To summarize, in children with sustained myeloid engraftment the concern that lymphocyte recovery after CBT could be delayed does not appear to be substantiated by our results.

Adolescent↗
PubMed2000

Clonal culture of fetal cells from maternal blood.

Successful isolation and genetic testing of fetal cells obtained from maternal blood could eliminate the risks associated with invasive prenatal testing. We used clonal in-vitro expansion of fetal haemopoietic cells and micromanipulation and fluorescent PCR of single colonies to obtain pure fetal colonies from peripheral blood of 12 healthy pregnant women. Of 2966 randomly selected colonies, 42 contained fetal and other cells and, for four women, two to four colonies each contained purely fetal cells. Detection of fetal cells has been hampered by rarity in maternal blood, but with our approach many cells are available for analysis.

Cells, Cultured↗
PubMed2000

Novel mutations of the von hippel-lindau tumor-suppressor gene and rare DNA hypermethylation in renal-cell carcinoma cell lines of the clear-cell type.

Renal-cell carcinoma (RCC) is the most common neoplasm of the kidney, accounting for about 3% of all adult malignancies. Histopathologically, 80% of all cases can be classified as clear-cell RCC. Of these, approximately 55% to 70% are associated with mutations in the von Hippel-Lindau (VHL) tumor-suppressor gene. Here, new mutations of the VHL gene were defined by the use of temperature gradient gel electrophoresis and subsequent sequencing. In addition, DNA hypermethylation, an alternative mechanism of VHL gene silencing, was evaluated by methylation-specific PCR. Twenty-six clear-cell, 3 chromophilic, and 2 chromophobic RCC cell lines were analyzed. Among the clear-cell RCC cell lines tested, 12 (47%) contained 13 mutations overall: 8 (62%) in exon 1, 3 (23%) in exon 2, and 2 (15%) in exon 3. Ten of these mutations have thus far not been described. All single base pair changes were transversions. Six mutations led to alteration of a single amino acid. Seven mutations generated a frameshift or a stop codon. One cell line contained a complex duplication of 36 bp. All cell lines with mutations showed loss of heterozygosity in the VHL gene. No mutations could be detected in the chromophilic or chromophobic RCC samples. Significant hypermethylation was not observed in any of the cell lines. These data provide further evidence that distinct mutations in the VHL gene are a characteristic feature of clear-cell RCC. In contrast, hypermethylation of the gene is probably a rare event. The high frequency of transversion mutations suggests a role for exogenous carcinogens in the etiology of clear-cell RCCs.

Adenocarcinoma, Clear Cell↗
PubMed2000

HLA-DRB1,3,4,5 and -DQB1 allele frequencies and HLA-DR/DQ linkage disequilibrium of 231 German caucasoid patients and their corresponding 821 potential unrelated stem cell transplants.

Allelic matching within the HLA-DRB1 and -DQB1 loci significantly improves the clinical outcome of hematopoietic stem cell transplantation. Consequently, allelic typing of these loci is strongly recommended for the unrelated stem cell donor selection. In this study, the HLA-DRB1,3,4,5 and -DQB1 alleles of 231 patients and their corresponding 821 nonrandom potential stem cell donors were determined to define compatible donor/recipient pairs. Highly accurate HLA typing data were achieved by PCR-SSOP and a combination of group specific PCR-SSP and subsequent sequencing-based typing of nearly the whole second exon of each locus. The alleles DRB1*07, *09, and *10 were analyzed by PCR-reverse dot blot hybridization instead of sequencing. Additionally, DRB1 homozygosity was verified by temperature gradient gel electrophoresis. The identified 2104 HLA-DRB1 and HLA-DQB1 alleles as well as data on HLA-DRB3, -DRB4, and -DRB5 alleles were applied to a statistical program and absolute and relative delta values of DR/DQ linkages were calculated. The achieved data on the HLA-DRB1 allele distribution and on DR/DQ associations in terms of subtypes significantly ensure the typing reliability, since rare allele combinations will result in further investigations. Furthermore, detailed data on the DR/DQ allele associations allow estimations of the number of HLA-A, -B, and -DR matched unrelated stem cell donors necessary for the identification of DRB and DQB subtype identical donors.

Alleles↗
PubMed2000

Successful treatment of relapsed CML after cord blood transplantation with donor leukocyte infusion IL-2 and IFNalpha.

A 3-year-old girl with BCR/ABL-positive CML relapsed after related HLA-identical cord blood transplantation. She was treated with three cycles of donor lymphocyte (DLI) infusion from her 15-month-old brother. Interferon alpha was added after the second DLI, whereas a trial of IL-2 had to be discontinued because of increasing immature myeloid cells in the blood smear. No signs of GVHD were observed, but she developed myelosuppression and needed one platelet and one red blood cell transfusion. She achieved a molecular remission after 6 months with transient molecular relapse followed by sustained remission for 15 months. Thus, DLI with or without interferon alpha might prove to be a promising treatment option with tolerable side-effects in relapsed CML after cord blood transplantation. Bone Marrow Transplantation (2000) 25, 219-222.

Blood Component Transfusion↗
PubMed1999

Identification of cord blood dendritic cells as an immature CD11c- population.

Dendritic cells (DC) are the main stimulators of primary T-cell responses and, thus, probably play a role in the immune reactions after stem cell transplantation. Very little is known about DC in cord blood (CB) and about their potential involvement in the low incidence and severity of acute graft-versus-host disease after CB transplantation. Here, CBDC were identified as a HLA-DR+ cell population, lacking the CD3, CD11b, CD14, CD16, CD19, CD34, CD56, and glycophorin A lineage markers (lin). This lin-/HLA-DR+ population represented 0.3% +/- 0.1% (mean +/- SD; range, 0.1% to 0. 6%; n = 15) of CB mononuclear cells, and CB contained 5.4 +/- 3.2 x 10(3) CBDC/mL (1.8 to 13.0 x 10(3); n = 15). CBDC expressed CD4, CD11a, CD18, CD45RA, CD50, CD54, and CD123, but showed no expression of CD1a, CD11c, CD33, CD40, CD45R0, CD80, CD83, and CD86 and only limited expression of CD58, CD102, and CD116. Despite this immature phenotype, immunomagnetically lin--enriched CBDC were potent stimulators of allogeneic CB T cells. As few as 266 +/- 107 (193 to 530; n = 10) lin-/HLA-DR+ CBDC stimulated a significant response. However, CBDC failed to take up protein or peptide antigens. Thus, in CB there is a prevalence of a DC subpopulation, resembling the CD11c- DC identified in tonsils, the so-called plasmacytoid T cells, which may exert a function distinct from the CD11c+ DC subpopulation.

Amino Acid Sequence↗
PubMed1999

Establishment of experimental conditions for the rapid detection of mutations in the von Hippel-Lindau gene by parallel temperature gradient gel electrophoresis.

Renal cell carcinoma (RCC) is the most common adult kidney neoplasm and is present in approximately 3% of all adult malignancies. Mutations of the von Hippel-Lindau (VHL) gene had been found in 55-70% of sporadic RCC and appear to be a critical event in the pathogenesis of clear-cell RCC. Several screening procedures for the detection of mutations in the VHL gene such as single-strand conformation polymorphism analysis, Southern blot and polymerase chain reaction (PCR)-employing methods had been used. Recently, the perpendicular temperature gradient gel electrophoresis (TGGE) was successfully applied to detect genetic alterations in the VHL gene. Here, the experimental conditions for parallel TGGE were established. The results on eleven samples with mutations in different exons demonstrate that parallel TGGE can be used as a simple and rapid method to detect mutations in the VHL gene. Several samples can be run at the same time, making parallel TGGE ideal for the screening of a large number of samples.

Adult↗