PubMed Health⌕ Search

Biomedical subjects

Rainer Haas

Publications and source records attributed to Rainer Haas.

At least 19 recordsLinked to original sources
PubMed2007

Serum proteome profiling detects myelodysplastic syndromes and identifies CXC chemokine ligands 4 and 7 as markers for advanced disease.

Myelodysplastic syndromes (MDS) are among the most frequent hematologic malignancies. Patients have a short survival and often progress to acute myeloid leukemia. The diagnosis of MDS can be difficult; there is a paucity of molecular markers, and the pathophysiology is largely unknown. Therefore, we conducted a multicenter study investigating whether serum proteome profiling may serve as a noninvasive platform to discover novel molecular markers for MDS. We generated serum proteome profiles from 218 individuals by MS and identified a profile that distinguishes MDS from non-MDS cytopenias in a learning sample set. This profile was validated by testing its ability to predict MDS in a first independent validation set and a second, prospectively collected, independent validation set run 5 months apart. Accuracy was 80.5% in the first and 79.0% in the second validation set. Peptide mass fingerprinting and quadrupole TOF MS identified two differential proteins: CXC chemokine ligands 4 (CXCL4) and 7 (CXCL7), both of which had significantly decreased serum levels in MDS, as confirmed with independent antibody assays. Western blot analyses of platelet lysates for these two platelet-derived molecules revealed a lack of CXCL4 and CXCL7 in MDS. Subtype analyses revealed that these two proteins have decreased serum levels in advanced MDS, suggesting the possibility of a concerted disturbance of transcription or translation of these chemokines in advanced MDS.

Biomarkers↗
PubMed2007

Functional and intracellular signaling differences associated with the Helicobacter pylori AlpAB adhesin from Western and East Asian strains.

Following adhesion of Helicobacter pylori to gastric epithelial cells, intracellular signaling leads to cytokine production, which causes H. pylori-related gastric injury. Two adjacent homologous genes (alpA and alpB), which encode H. pylori outer membrane proteins, are thought to be associated with adhesion and cytokine induction. We co-cultured gastric epithelial cells with wild type H. pylori strains and their corresponding alpA/alpB-deleted mutants (DeltaalpAB). Results were confirmed by complementation. Flow cytometry confirmed that AlpAB was involved in cellular adhesion. Deletion of alpAB reduced interleukin (IL)-6 induction in gastric epithelial cells. Deletion of alpAB reduced IL-8 induction with East Asian but not with Western strains. All AlpAB-positive strains tested activated the extracellular signal-regulated kinase, c-Fos, and cAMP-responsive element-binding protein. Activation of the Jun-N-terminal kinase, c-Jun, and NF-kappaB was exclusive to AlpAB from East Asian strains. DeltaalpAB mutants poorly colonized the stomachs of C57BL/6 mice and were associated with lower mucosal levels of KC and IL-6. Our results suggest that AlpAB may induce gastric injury by mediating adherence to gastric epithelial cells and by modulating proinflammatory intracellular signaling cascades. Known geographical differences in H. pylori-related clinical outcomes may relate to differential effects of East Asian and Western types of AlpAB on NF-kappaB-related proinflammatory signaling pathways.

Adhesins, Bacterial↗
PubMed2007

Long-term follow-up of patients with non-Hodgkin lymphoma following myeloablative therapy and autologous transplantation of CD34+-selected peripheral blood progenitor cells.

Graft engineering by CD34(+) selection of peripheral blood progenitor cells (PBPC) has been used in non-Hodgkin lymphoma (NHL) with the aim to reduce relapse related to tumor cells within the graft. From September 1995 to January 2000, 39 patients with newly diagnosed (n = 31) or relapsed (n = 8) NHL were treated in our institution with myeloablative therapy followed by CD34(+) selected autologous PBPC transplantation. Thirty-one patients were diagnosed with follicular lymphoma, and eight patients with mantle-cell lymphoma. All patients had advanced disease (26% of patients stage III and 74% stage IV, Ann Arbor classification). Induction therapy resulted in a complete remission in 17 patients and a partial remission in 22 patients. PBPC were mobilized after cytotoxic chemotherapy with granulocyte colony-stimulating factor support. CD34(+) selection was performed using immunomagnetic beads (Baxter Isolex 300SA or 300i Magnetic Cell Separation System). Most patients (85%) received total body irradiation and high-dose cyclophosphamide as myeloablative regimen. Twelve patients also received rituximab 375 mg/m(2) before radiation and before the start of the cyclophosphamide treatment. The mean CD34(+) cell number for transplantation was 6.5 x 10(6) CD34(+) cells/kg of body weight. Platelet recovery (>20,000/microl median on day 13) and leukocyte recovery (>1,000/microl median on day 12) were within expected range. The estimated median follow-up was 47 months. The probabilities of freedom from progression, overall survival, and event-free survival 4 years after transplantation were 96%, 90%, and 87%, respectively, for patients with follicular lymphoma and 42%, 63%, and 33%, respectively, for patients with mantle-cell lymphoma. Risk factors for relapse were age and extranodal manifestation of disease. The rate of lethal infections in the 12-month follow-up period was 8%. We conclude that CD34(+) selection of autologous transplants following myeloablative therapy is feasible and results in long-term remission in the majority of patients, but the procedure is probably related to a higher rate of lethal infections.

Adult↗
PubMed2006

Helicobacter pylori BabA expression, gastric mucosal injury, and clinical outcome.

BACKGROUND & AIMS: The blood grou. METHODS: We compared the ability of published PCR-based methods to assess BabA status with BabA immunoblotting and Lewis b (Le(b)) binding activity assays. We also used immunoblotting to examine the relationship between clinical presentation and levels of BabA expression. RESULTS: Immunoblotting and Le(b) binding assays for 80 strains revealed 3 levels of BabA expression: BabA high producers (BabA-H) with Le(b) binding activity, BabA low producers (BabA-L) without Le(b) binding activity, and BabA-negative. BabA-negative strains lacked the babA gene. PCR methods to determine BabA status yielded poor results. babA1 sequences were never detected. BabA expression was examined in 250 strains from Western countries and 270 strains from East Asia. The results failed to confirm any relationship between triple-positive status (cagA-positive/vacA s1/BabA-H) and clinical outcome. BabA-negative strains typically were cagA-negative/vacA s2 and were associated with gastritis. BabA-L strains showed a higher level of mucosal injury and were associated more frequently with duodenal ulcer and gastric cancer than the other groups. CONCLUSIONS: Information gained from currently used PCR-based methods must be interpreted with caution. Le(b) binding activity does not accurately reflect the severity of mucosal damage or the clinical outcome. Quantitation of BabA expression revealed that Le(b)-nonbinding BabA-L strains are associated with higher levels of mucosal injury and clinical outcome.

Adenocarcinoma↗
PubMed2006

Myelodysplastic syndromes in patients younger than age 50.

PURPOSE: Myelodysplastic syndromes (MDS) mainly occur in the elderly but can affect younger individuals too. The latter require special consideration to identify suitable candidates for allogeneic stem-cell transplantation, a potentially curative approach carrying a high risk of treatment-related complications. PATIENTS AND METHODS: We report the largest series of young MDS patients as yet, including 232 patients younger than 50 years. Their clinical characteristics and prognosis are compared with 2,496 patients older than 50 years. RESULTS: Survival was significantly longer in the younger versus older age group (40 v 23 months, respectively; P < .00005). The difference arose from patients belonging to the low- and intermediate-I-risk categories of the International Prognostic Scoring System (median survival not reached v 45 months, respectively; P < .00005). In contrast, survival was identical for both age groups (8 months for both younger and older patients; P = .81) in the intermediate-II-and high-risk categories. Established classification systems and risk scores were applicable to young patients with primary MDS. Interestingly, a particularly large difference in median survival time was seen between the intermediate-I-and intermediate-II-risk groups (176 v 8 months, respectively). For low-risk patients, the overall survival rate was more than 86% at 20 years. CONCLUSION: According to these results, aggressive treatment approaches should rarely be recommended to younger MDS patients belonging to the low and intermediate-I risk groups.

Adolescent↗
PubMed2006

Exisulind induces apoptosis in advanced myelodysplastic syndrome (MDS) and acute myeloid leukaemia/MDS.

The influence of Exisulind on the viability and apoptosis of CD34(+) stem cells from patients with advanced myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML)/MDS was investigated. In eight out of 10 patient samples Exisulind reduced the fraction of viable cells by inducing apoptosis. We found evidence that Exisulind-mediated apoptosis depends on c-Jun NH(2)-terminal kinase (JNK) activation. Addition of a specific JNK-inhibitor to Exisulind-treated advanced MDS and AML/MDS cells partly abrogated apoptosis. We propose that Exisulind is tested in clinical phase I/II trials for the treatment of advanced MDS and AML/MDS.

Acute Disease↗
PubMed2006

X-linked sideroblastic anemia associated with a novel ALAS2 mutation and unfortunate skewed X-chromosome inactivation patterns.

Historically X-linked sideroblastic anemia, with rare exceptions, was thought to be manifested only in males. Since the discovery of the erythroid-specific isoform of 5-aminolevulinate synthase (ALAS2) and the cloning of its gene (ALAS2) 15 years ago, mutation analysis has revealed that clinical expression of this X-linked disorder is prevalent in females as well. However, presence of the disease in both genders within affected kindreds appears to be very uncommon. We report a unique family with the disorder in three women who have had widely disparate clinical courses. The anemia is associated with a previously unrecognized ALAS2 mutation (Arg436Trp) and is unresponsive to pyridoxine. To clarify the varied clinical courses of the patients, X-chromosome inactivation patterns were examined in hematopoietic and non-hematopoietic cells. We observed inactivation patterns supporting the conclusions that one daughter has a mild phenotype at age 31 because of moderate constitutive skewed X-chromosome inactivation, another daughter with clinical onset at age 16 is severely affected due to extreme constitutive X-skewing, whereas the mother developed progressive anemia in the fifth decade as she acquired an age-related non-random X-inactivation in hematopoietic cells. In addition, we observed random X-inactivation in reticulocytes of all three women that contrasted with a markedly skewed inactivation pattern in bone marrow erythroid cells. This discordance is attributable to apoptosis of erythroid precursors derived from progenitor cells with an active X-chromosome bearing the ALAS2 mutation. The features of the disorder in this family are also instructive in regard to the differential diagnosis of sideroblastic anemias in women.

5-Aminolevulinate Synthetase↗
PubMed2006

Rituximab long-term maintenance therapy after autologous stem cell transplantation in patients with B-cell non-Hodgkin's lymphoma.

Treatment of B-cell non-Hodgkin's lymphomas (NHL) with either Rituximab alone or in combination with cytotoxic chemotherapy has been effective without major side effects. Thus, Rituximab maintenance therapy after autologous peripheral blood stem cell transplantation (PBSCT) might represent an improvement in NHL therapy. We therefore retrospectively analyzed the efficacy and side effects of monthly long-term Rituximab maintenance therapy after PBSCT in 27 patients with NHL. In median 10 infusions of Rituximab were given after PBSCT in time intervals of 1 month. Molecular monitoring of t(14;18) was performed using nested as well as quantitative real time polymerase chain reaction (RT-PCR) based on the LightCycler technology. Side effects according to common toxicity criteria (CTC) > II did mainly affect the hematopoietic system. In total, 10 patients (37%) suffered form grade III-IV hematotoxicity. Except for two patients with cutaneous Varicella-Zoster infection no serious infectious complications (CTC grade III/IV) occurred. No patient died because of treatment-related causes. This adverse event data compared favorably to the published data. Three patients had t(14;18) nested RT-PCR positive results before Rituximab therapy and converted to negativity after Rituximab therapy. We conclude that a prolonged Rituximab maintenance therapy after PBSCT with monthly administration is reliable and safe.

Adult↗
PubMed2006

Alternating versus concurrent schedules of imatinib and chemotherapy as front-line therapy for Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL).

The best strategy for incorporating imatinib in front-line treatment of Ph+ acute lymphoblastic leukemia (ALL) has not been established. We enrolled 92 patients with newly diagnosed Ph+ ALL in a prospective, multicenter study to investigate sequentially 2 treatment schedules with imatinib administered concurrent to or alternating with a uniform induction and consolidation regimen. Coadministration of imatinib and induction cycle 2 (INDII) resulted in a complete remission (CR) rate of 95% and polymerase chain reaction (PCR) negativity for BCR-ABL in 52% of patients, compared with 19% in patients in the alternating treatment cohort (P = .01). Remarkably, patients with and without a CR after induction cycle 1 (INDI) had similar hematologic and molecular responses after concurrent imatinib and INDII. In the concurrent cohort, grades III and IV cytopenias and transient hepatotoxicity necessitated interruption of induction in 87% and 53% of patients, respectively; however, duration of induction was not prolonged when compared with patients receiving chemotherapy alone. No imatinib-related severe hematologic or nonhematologic toxicities were noted with the alternating schedule. In each cohort, 77% of patients underwent allogeneic stem cell transplantation (SCT) in first CR (CR1). Both schedules of imatinib have acceptable toxicity and facilitate SCT in CR1 in the majority of patients, but concurrent administration of imatinib and chemotherapy has greater antileukemic efficacy.

Adult↗
PubMed2006

Successful treatment of relapsed AML after allogeneic stem cell transplantation with azacitidine.

Therapeutic options for patients with relapse of MDS or high risk AML after allogeneic stem cell transplantation are limited. We here present the case of a 64-year-old female patient with MDS, who received peripheral blood stem cells from her HLA-identical brother after a non-myeloablative conditioning regimen. Two months after allogeneic transplantation she suffered from a relapse, now fulfilling WHO criteria for AML with a bone marrow blast count of 91%. We then decided to treat her with azacitidine, a DNA methyltransferase inhibitor with proven antileukemic activity. The patient achieved a complete haematological response after two cycles and full donor chimerism after a single dose of donor lymphocytes. We postulate that azacitidine acts through a direct reduction of malignant cells and may in addition augment the immunologic effects of donor lymphocyte infusions.

Acute Disease↗
PubMed2006

[Differentiation potential of stem cells from bone marrow].

Hematopoietic organs such as bone marrow contain various stem and progenitor cells with a differentiation capability exceeding hematopoiesis, a process also referred to as plasticity. Stem cells in bone marrow are hematopoietic stem cells, mesenchymal stem cells, and multipotent progenitor cells. Several examples for the development of stem cells of hematopoietic organs into nonhematopoietic tissue open novel ways in regenerative medicine. Animal experiments showed generation of neuronal tissue, cardiomyocytes and functional hepatocytes in injured tissue from bone marrow stem cells. Interpreting these results one has to keep in mind that besides transdifferentiation also cell fusion or heterogeneous stem cell populations might contribute to tissue regeneration. First clinical studies on therapy with bone marrow stem cells in myocardial infarction or liver embolization showed promising results.

Antigens, CD34↗
PubMed2006

Absence of the JAK2 mutation V617F in CD34+ hematopoietic stem and progenitor cells from patients with BCR-ABL-positive CML in chronic phase and blast crisis.

In this study, we examined highly enriched CD34+ cells from patients with BCR-ABL-positve CML in chronic phase or blast crisis for the JAK2 V617F activation mutation by sequencing. The cells examined did not bear the mutation irrespective of the disease stage. This finding suggests that the previously described increase of expression and kinase activity of JAK2 in CML cells does not result from the JAK2 V617F activation mutation and that transformation into blast crisis is not associated with the occurrence of this mutation.

Amino Acid Substitution↗
PubMed2006

The influence of the pituitary tumor transforming gene-1 (PTTG-1) on survival of patients with small cell lung cancer and non-small cell lung cancer.

BACKGROUND: PTTG-1 (pituitary tumor transforming gene) is a novel oncogene that is overexpressed in tumors, such as pituitary adenoma, breast and gastrointestinal cancers as well as in leukemia. In this study, we examined the role of PTTG-1 expression in lung cancer with regard to histological subtype, the correlation of PTTG-1 to clinical parameters and relation on patients' survival. METHODS: Expression of PTTG-1 was examined immunohistochemically on formalin-fixed, paraffin-embedded tissue sections of 136 patients with small cell lung cancer (SCLC) and 91 patients with non-small cell lung cancer (NSCLC), retrospectively. The intensity of PTTG-1 expression as well as the proportion of PTTG-1 positive cells within a tumor was used for univariate and multivariate analysis. RESULTS: PTTG-1 expression was observed in 64% of SCLC tumors and in 97.8% of NSCLC tumors. In patients with SCLC, negative or low PTTG-1 expression was associated with a shorter mean survival time compared with patients with strong PTTG-1 expression (265 +/- 18 days vs. 379 +/- 66 days; p = 0.0291). Using the Cox regression model for multivariate analysis, PTTG-1 expression was a significant predictor for survival next to performance status, tumor stage, LDH and hemoglobin. In contrast, in patients with NSCLC an inverse correlation between survival and PTTG-1 expression was seen. Strong PTTG-1 expression was associated with a shorter mean survival of 306 +/- 58 days compared with 463 +/- 55 days for those patients with no or low PTTG-1 intensities (p = 0.0386). Further, PTTG-1 expression was associated with a more aggressive NSCLC phenotype with an advanced pathological stage, extensive lymph node metastases, distant metastases and increased LDH level. Multivariate analysis using Cox regression confirmed the prognostic relevance of PTTG-1 expression next to performance status and tumor stage in patients with NSCLC. CONCLUSION: Lung cancers belong to the group of tumors expressing PTTG-1. Dependent on the histological subtype of lung cancer, PTTG-1 expression was associated with a better outcome in patients with SCLC and a rather unfavourable outcome for patients with NSCLCs. These results may reflect the varying role of PTTG-1 in the pathophysiology of the different histological subtypes of lung cancer.

Journal Article↗
PubMed2006

Use of RNA interference to inhibit integrin subunit alphaV-mediated angiogenesis.

One of the central molecules in capillary formation during angiogenesis is the integrin alphaVbeta3. The aim of this study was to inhibit alphaV-mediated angiogenesis in vitro using RNAs (siRNA) as well as antisense oligodeoxyribonucleotides (asON). Five siRNAs, against the alphaV chain of alphaVbeta3, and three asON, which had the respective sequence of the antisense sequence of three of the siRNAs molecules, were examined. Two of the siRNAs and their respective asON were designed on the basis of computer-predicted secondary structure analysis of alphaV mRNA. The different molecules were transfected into human umbilical vein endothelials cells (HUVEC) using lipofection. Following stimulation by PMA, two siRNAs showed a dose-dependent inhibition of PMA-induced alphaV mRNA and protein upregulation, as assessed by real-time RT-PCR and flow cytometry. At a concentration of 25 nM a complete inhibition of protein upregulation was found using siRNAs while transfection of the respective asON sequences reduced the protein upregulation only by 44%. To evaluate the anti-angiogenic potential a cell culture model of human angiogenesis based on the co-cultivation of endothelial cells and dermal fibroblasts was used. Transfection of the siRNA sequence (50 nM) resulted in an inhibition of the total length of capillary-like tubules by 40.6% in comparison to 21.1% using the respective asON sequence. In conclusion, siRNA-based downregulation of alphaV expression showed a stronger inhibition of capillary tube formation in an angiogenesis in vitro assay, than asON having the same sequence as the antisense strand of the siRNAs. Therefore, siRNAs are useful tools for functional alphaV knock-down experiments and might be a therapeutic alternative for antagonists which bind directly to the integrins alphaVbeta3 or alphaVbeta5.

Apoptosis↗
PubMed2006

The histone deacetylase (HDAC) inhibitor valproic acid as monotherapy or in combination with all-trans retinoic acid in patients with acute myeloid leukemia.

BACKGROUND: Valproic acid (VPA) inhibits histone deacetylase activity and, synergizing with all-trans retinoic acid (ATRA), achieves differentiation induction of myeloid blast cells in vitro. METHODS: We used VPA in 58 patients with acute myeloid leukemia (AML) who were too old and/or medically unfit to receive intensive chemotherapy (32 AML secondary to myelodysplastic syndrome [MDS], 22 de novo AML, 4 AML secondary to myeloproliferative syndrome). VPA serum concentrations were 50-100 mug/mL. Thirty-one patients received VPA monotherapy. ATRA was added later in 13 patients who did not respond or who relapsed. Another 27 patients received VPA plus ATRA from the start. Median treatment duration was 93 days for VPA and 88 days for ATRA. RESULTS: The response rate was only 5% according to International Working Group (IWG) criteria for AML but was 16% when IWG response criteria for MDS were used, which capture hematologic improvement and stabilization of the disease. These endpoints, which are not necessarily correlated with diminishing blast counts, are relevant for the patients' quality of life. Among 23 patients with a peripheral blast count > 5%, 6 (26%) showed a diminishing blast count, and 5 of these had a complete peripheral blast clearance. CONCLUSIONS: Future trials should combine VPA with chemotherapy or demethylating agents.

Acute Disease↗
PubMed2006

Sustained G-CSF plasma levels following administration of pegfilgrastim fasten neutrophil reconstitution after high-dose chemotherapy and autologous blood stem cell transplantation in patients with multiple myeloma.

OBJECTIVE: Pegfilgrastim has shown to decrease the duration of severe neutropenia after conventional chemotherapy, but its use after high-dose chemotherapy and autologous blood stem cell transplantation has not been established yet. Therefore we studied the efficacy and the pharmacokinetic profile of pegfilgrastim in patients with multiple myeloma undergoing high-dose chemotherapy. METHOD: In total, 21 patients received a single subcutaneous injection of 6 mg pegfilgrastim on day +1 after transplantation and pegfilgrastim plasma levels were measured daily by enzyme-linked immunosorbent assay. Clinical outcome was compared with pegfilgrastim levels of 282 plasma samples and data of a historical control group of patients without granulocyte colony-stimulating factor (G-CSF) support. RESULTS: Pegfilgrastim levels showed an inverse correlation (r = -0.68, p < 0.01) with neutrophil counts. Peak levels were reached at day +4 (94 ng/mL; range: 37-205) and were maintained until day +7 (85 ng/mL; range: 35-186). Comparison with the control group without G-CSF support showed that time to neutrophil reconstitution was significantly shorter in the pegfilgrastim group with 10 vs 15 days, respectively (p < 0.001). There was no correlation of pegfilgrastim levels and the duration of neutropenia, although patients with a fivefold increase in neutrophil counts the day after pegfilgrastim administration had a significantly shorter median duration of neutropenia in comparison to patients who were less susceptible to G-CSF stimulation (5 vs 7 days, p < 0.01). CONCLUSION: Neutrophil reconstitution after high-dose chemotherapy could be accelerated by the use of pegfilgrastim in patients with myeloma. Responsiveness of neutrophils to pegfilgrastim before neutropenia was correlated with faster neutrophil reconstitution, whereas G-CSF levels had no impact on neutrophil recovery.

Adult↗
PubMed2006

Refractory anaemia with excess of blasts (RAEB): analysis of reclassification according to the WHO proposals.

The French-American-British (FAB) classification assigns patients with myelodysplastic syndromes to the category of refractory anaemia with excess blasts (RAEB) if they have a medullary blast count of 5-20%, and/or a peripheral blast count of 2-5%. The new World Health Organization (WHO) classification subdivides RAEB into RAEB I with a medullary blast count < or =10% and a peripheral blast count < or =5% and RAEB II with >10% medullary and/or >5% peripheral blasts. RAEB II is also diagnosed if Auer rods are present. In 558 patients, we analysed these subtypes of RAEB in terms of haematological characteristics, karyotype anomalies and prognosis. RAEB I was diagnosed in 256 and RAEB II in 302 patients. In the RAEB II group, 22% of patients had >5% peripheral blasts or the presence of Auer rods. The median survival was 16 months for RAEB I as compared with 9 months for RAEB II. Patients with Auer rods, regardless of their medullary and peripheral blast count, had no worse prognosis. No significant differences were identified between the RAEB subtypes with respect to clinical, morphological, haematological and cytogenetic parameters. The survival data support the WHO reclassification of RAEB based on peripheral and medullary blast counts and Auer rods. The WHO classification is useful for diagnosis and provides risk stratification, supported by cytogenetic data for clinical decision making, identifying those RAEB patients with an unfavourable prognosis who should be offered chemotherapy or stem cell transplantation.

Adolescent↗