Publications by authors named "Drexler H"

To develop more active catalysts for the rhodium-catalyzed addition of carboxylic acids to terminal alkynes furnishing anti-Markovnikov Z enol esters, a thorough study of the rhodium complexes involved was performed. A number of rhodium complexes were characterized by NMR, ESI-MS, and X-ray analysis and applied as catalysts for the title reaction. The systematic investigations revealed that the presence of chloride ions decreased the catalyst activity.

View Article and Find Full Text PDF

Aromatic amines (AA) are compounds of different carcinogenic potency causing occupational bladder cancer. The percutaneous absorption of AA is mostly appraised to be high. Many AA are, therefore, assigned with skin notations.

View Article and Find Full Text PDF

The human DNA mismatch repair (MMR) gene family comprises four MutL paralogues capable of forming heterodimeric MutLα (MLH1-PMS2), MutLβ (MLH1-PMS1), and MutLγ (MLH1-MLH3) protein complexes. Human MutL subunits PMS2 and MLH3 contain an evolutionarily conserved amino acid motif DQHA(X)2E(X)4E identified as an endonucleolytic domain capable of incising a defective DNA strand. PMS2 of MutLα is generally accepted to be the sole executor of endonucleolytic activity, but since MLH3 was shown to be able to perform DNA repair at low levels in vitro, our aim was to investigate whether or not MLH3 is activated as a backup under MutLα-deficient conditions.

View Article and Find Full Text PDF

Homeobox genes encode transcription factors ubiquitously involved in basic developmental processes, deregulation of which promotes cell transformation in multiple cancers including hematopoietic malignancies. In particular, NKL-family homeobox genes TLX1, TLX3 and NKX2-5 are ectopically activated by chromosomal rearrangements in T-cell neoplasias. Here, using transcriptional microarray profiling and RQ-PCR we identified ectopic expression of NKL-family member NKX2-1, in a diffuse large B-cell lymphoma (DLBCL) cell line SU-DHL-5.

View Article and Find Full Text PDF

Chromosomal rearrangements are common features of most cancers, where they contribute to deregulated gene expression. Chromothripsis is a recently described oncogenic mechanism whereby small genomic pieces originating from one chromosomal region undergo massive rearrangements in a single step. Here, we document chromothripsis in Hodgkin lymphoma (HL) cell lines by genomic profiling, showing alternating amplicons of defined chromosomal regions.

View Article and Find Full Text PDF

Recently described and fully characterized trinuclear rhodium-hydride complexes [{Rh(PP*)H}3(μ2-H)3(μ3-H)][anion]2 have been investigated with respect to their formation and role under the conditions of asymmetric hydrogenation. Catalyst-substrate complexes with mac (methyl (Z)-N-acetylaminocinnamate) ([Rh(tBu-BisP*)(mac)]BF4, [Rh(Tangphos)(mac)]BF4, [Rh(Me-BPE)(mac)]BF4, [Rh(DCPE)(mac)]BF4, [Rh(DCPB)(mac)]BF4), as well as rhodium-hydride species, both mono-([Rh(Tangphos)-H2(MeOH)2]BF4, [Rh(Me-BPE)H2(MeOH)2]BF4), and dinuclear ([{Rh(DCPE)H}2(μ2-H)3]BF4, [{Rh(DCPB)H}2(μ2-H)3]BF4), are described. A plausible reaction sequence for the formation of the trinuclear rhodium-hydride complexes is discussed.

View Article and Find Full Text PDF

Introduction: There is an ongoing debate about the optimal use of metal-on-metal (MoM) bearings in total hip replacement, since there are uncertainties about local and systemic adverse effects due to wear and corrosion of these bearings. Despite various national recommendations, efforts to achieve international harmonization of specific evidence-based recommendations for best practice are still lacking.

Hypothesis: An international consensus study group should be able to develop recommendations on the use and monitoring of MoM bearings, preferably at the European level, through a multidisciplinary approach, by integrating the perspectives of various stakeholders.

View Article and Find Full Text PDF

Hydrogen produced from renewable resources is a promising potential source of clean energy. With the help of low-temperature proton-exchange membrane fuel cells, molecular hydrogen can be converted efficiently to produce electricity. The implementation of sustainable hydrogen production and subsequent hydrogen conversion to energy is called "hydrogen economy".

View Article and Find Full Text PDF

Biomonitoring is an essential occupational-medical instrument for assessing the exposure of chemical agents of workers. It is an integral part of preventive medical examinations as far as established analytical procedures and values for evaluating biomonitoring results are available. The DFG Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has published values for evaluating biomonitoring results.

View Article and Find Full Text PDF

Analyses of cadmium concentrations in biological material are performed using inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), but also electrochemical methods, neutron activation analysis (NAA), and X-ray fluorescence spectrometry (XRF). The predominant sample matrices include blood, plasma, serum, and urine, as well as hair, saliva, and tissue of kidney cortex, lung, and liver. While cadmium in blood reveals rather the recent exposure situation, cadmium in urine reflects the body burden and is an indicator for the cumulative long term exposure.

View Article and Find Full Text PDF

Terminally differentiated cells can be reprogrammed to pluripotency by the forced expression of Oct4, Sox2, Klf4 and c-Myc. However, it remains unknown how this leads to the multitude of epigenetic changes observed during the reprogramming process. Interestingly, Oct4 is the only factor that cannot be replaced by other members of the same family to induce pluripotency.

View Article and Find Full Text PDF

Fusions of the tyrosine kinase domain of JAK2 with multiple partners occur in leukemia/lymphoma where they reportedly promote JAK2-oligomerization and autonomous signalling, Affected entities are promising candidates for therapy with JAK2 signalling inhibitors. While JAK2-translocations occur in myeloid, B-cell and T-cell lymphoid neoplasms, our findings suggest their incidence among the last group is low. Here we describe the genomic, transcriptional and signalling characteristics of PCM1-JAK2 formed by t(8;9)(p22;p24) in a trio of cell lines established at indolent (MAC-1) and aggressive (MAC-2A/2B) phases of a cutaneous T-cell lymphoma (CTCL).

View Article and Find Full Text PDF

Activities as diverse as migration, proliferation and patterning occur simultaneously and in a coordinated fashion during tissue morphogenesis. In the growing vasculature, the formation of motile, invasive and filopodia-carrying endothelial sprouts is balanced with the stabilization of blood-transporting vessels. Here, we show that sprouting endothelial cells in the retina have high rates of VEGF uptake, VEGF receptor endocytosis and turnover.

View Article and Find Full Text PDF

The genetic basis of hypodiploid acute lymphoblastic leukemia (ALL), a subtype of ALL characterized by aneuploidy and poor outcome, is unknown. Genomic profiling of 124 hypodiploid ALL cases, including whole-genome and exome sequencing of 40 cases, identified two subtypes that differ in the severity of aneuploidy, transcriptional profiles and submicroscopic genetic alterations. Near-haploid ALL with 24-31 chromosomes harbor alterations targeting receptor tyrosine kinase signaling and Ras signaling (71%) and the lymphoid transcription factor gene IKZF3 (encoding AIOLOS; 13%).

View Article and Find Full Text PDF

Genetic heterogeneity is common in tumors, explicable by the development of subclones with distinct genetic and epigenetic alterations. We describe an in vitro model for cancer heterogeneity, comprising the diffuse large B-cell lymphoma cell line U-2932 which expresses two sets of cell surface markers representing twin populations flow-sorted by CD20 vs CD38 expression. U-2932 populations were traced to subclones of the original tumor with clone-specific immunoglobulin IgVH4-39 hypermutation patterns.

View Article and Find Full Text PDF

According to international guidelines skin penetration experiments can be carried out using freshly excised or frozen stored skin. However, this recommendation refers to data obtained in experiments with human cadaver skin. In our study, the percutaneous penetration of the occupationally relevant chemicals anisole, cyclohexanone and 1,4-dioxane was investigated for freshly excised as well as for 4 and 30 days at -20°C stored human skin using the diffusion cell technique.

View Article and Find Full Text PDF

Background: The cumulative effect of solar ultraviolet (UV) radiation is responsible for the worldwide increase in non-melanoma skin cancer, a category that includes squamous cell carcinoma and its precursors (the actinic keratoses) as well as basal-cell carcinoma. Non-melanoma skin cancer is the most common type of cancer in areas of the world with a light-skinned population. The occupational exposure to UV radiation is high in many outdoor occupations; recent studies suggest that persons working in such occupations are more likely to develop non-melanoma skin cancer.

View Article and Find Full Text PDF

Cytogenetic analysis is performed on cell cultures for several reasons, notably, to perform identity checks by verifying species of origin or the retention of key chromosome rearrangements in cell lines described previously. De novo chromosome analysis is usually performed when characterizing cancer cell lines for the presence of neoplastic rearrangements associated with specific tumors. This usually involves fluorescence in situ hybridization (FISH) using clones covering gene loci near recurrent chromosome breakpoints.

View Article and Find Full Text PDF