PubMed Health⌕ Search

Biomedical subjects

Raymund Buhmann

Publications and source records attributed to Raymund Buhmann.

5 recordsLinked to original sources
PubMed2005

Aptamers--basic research, drug development, and clinical applications.

Since its discovery in the early 1990s, aptamer technology has progressed tremendously. Automated selection procedures now allow rapid identification of DNA and RNA sequences that can target a broad range of extra- and intracellular proteins with nanomolar affinities and high specificities. The unique binding properties of nucleic acids, which are amenable to various modifications, make aptamers perfectly suitable for different areas of biotechnology. Moreover, the approval of an aptamer for vascular endothelial growth factor by the US Food and Drug Administration highlights the potential of aptamers for therapeutic applications. This review summarizes recent developments and demonstrates that aptamers are valuable tools for diagnostics, purification processes, target validation, drug discovery, and even therapeutic approaches.

Animals↗
PubMed2005

Chromosomal translocations are associated with poor prognosis in chronic lymphocytic leukemia.

In chronic lymphocytic leukemia (CLL), chromosomes usually evade detailed cytogenetic analyses because cells poorly respond to the traditionally used set of mitogens. We applied novel technologies, such as stimulation of CLL cells either with CD40 ligand or with a combination of CpG-oligodeoxynucleotides and IL-2, to increase the frequency of metaphase spreads for detailed chromosome analysis in 96 patients with CLL. This approach revealed that translocations occurred in 33 of 96 (34%) of our patients with CLL. The presence of translocations defined a new prognostic subgroup because these patients have significantly shorter median treatment-free survival (24 months vs 106 months; P < .001) and significantly inferior overall survival (OS; median, 94 months) than patients without translocations (346 months; P < .001). In multivariate analysis-including Binet stage, complex karyotype, CD38 expression, and 17p deletions-translocation proved to be the prognostic marker with the highest impact for an unfavorable clinical outcome (P < .001). In summary, we identified a new subgroup of patients with CLL defined by chromosomal trans-locations and poor prognosis. Our data may facilitate the identification of molecular events crucial for transforming activity in this disease and should have implications for risk-adapted clinical management of patients with CLL.

ADP-ribosyl Cyclase 1↗
PubMed2002

Efficient gene transfer of CD40 ligand into primary B-CLL cells using recombinant adeno-associated virus (rAAV) vectors.

B cells of chronic lymphocytic leukemia (B-CLL) are resistant to transduction with most currently available vector systems. Using an optimized adenovirus-free packaging system, recombinant adeno-associated virus (rAAV) vectors coding for the enhanced green fluorescent protein (AAV/EGFP) and CD40 ligand (AAV/CD40L) were packaged and highly purified resulting in genomic titers up to 3 x 10(11)/mL. Cells obtained from 24 patients with B-CLL were infected with AAV/EGFP or AAV/CD40L at a multiplicity of infection (MOI) of 100 resulting in transgene expression in up to 97% of cells as detected by flow cytometry 48 hours after infection. Viral transduction could be specifically blocked by heparin. Transduction with AAV/CD40L resulted in up-regulation of the costimulatory molecule CD80 not only on infected CLL cells but also on noninfected bystander leukemia B cells, whereas this effect induced specific proliferation of HLA-matched allogeneic T cells. Vaccination strategies for patients with B-CLL using leukemia cells infected ex vivo by rAAV vectors now seems possible in the near future.

Adult↗
PubMed2002

CD40L stimulation enhances the ability of conventional metaphase cytogenetics to detect chromosome aberrations in B-cell chronic lymphocytic leukaemia cells.

Conventional metaphase cytogenetics underestimates the frequency of specific chromosome aberrations in B-cell chronic lymphocytic leukaemia (B-CLL) as a result of the very low proliferative activity of these cells in vitro. New molecular approaches, such as fluorescence in situ hybridization (FISH) or comparative genomic hybridization (CGH), may circumvent this problem, at least in part, but these techniques are either strongly dependent on the knowledge of candidate regions or detect only unbalanced aberrations. In the present study, we analysed 27 B-CLL peripheral blood samples by metaphase cytogenetics after CD40 ligand (CD40L)-induced cell cycle stimulation. In comparison with the simultaneous use of B-cell mitogens such as 12-O-tetradecanoylphorbol-13-acetate (TPA), lipopolysaccharide (LPS) and pokeweed mitogen (PWM), CD40L stimulation of B-CLL cells induced a threefold increase in metaphases amenable to analysis by conventional cytogenetics. The analysis of these metaphases confirmed all genetic abnormalities detected by FISH. Moreover, CD40L-enhanced cytogenetics revealed complex karyotypic aberrations in 11 out of 27 patients (41%). In one case, a balanced translocation t(11;16)(p15;p13.1), so far unreported in B-CLL, was detected. Taken together, the results of our study show the potential of CD40L-enhanced metaphase cytogenetics to detect more and new chromosome aberrations in B-CLL.

3T3 Cells↗