Publications by authors named "Siebertz B"

A new cell isolation technique linked to the aureka® micromanipulation system (aureka®) was used to pick sperm from mixed samples containing sperm and epithelial cells. Both cell types were stained using the HY-LITER™ high-resolution, fluorescent staining kit. To isolate a single sperm of interest under a fluorescent microscope, a specific microsphere picking technique was used.

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In an effort to gain deeper insight into the molecular processes underlying neurodegeneration in Parkinson's disease, we performed gene expression profiling at several early time points after MPTP-injection into old (1-year) mice. We used a PCR-based gene expression profiling method, digital expression pattern display (DEPD), a method of very high sensitivity and reproducibility, which displays almost all transcripts of a tissue. To identify cell death-associated genes, we defined clusters of differentially expressed transcripts with expression behaviour that correlated with the temporal profile of cell death progression and characterized one of these cell death clusters further.

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Heparan sulphate proteoglycans and the extracellular matrix of bone-marrow-stromal cells are important components of the microenvironment of haematopoietic tissues and are involved in the interaction of haematopoietic stem and stromal cells. Previous studies have emphasized the role of heparan sulphate proteoglycan synthesis by bone-marrow-stromal cells. In the present study we describe the expression of glypican-4 (GPC-4), belonging to the glypican family, in bone-marrow-stromal cells and haematopoietic-progenitor cells of human and murine origin.

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Objective: We have previously shown that human articular chondrocytes synthesize large amounts of interleukin-6 (IL-6) upon stimulation with proinflammatory cytokines and that they express the IL-6 receptor. The present study was undertaken to analyze whether different IL-6-type cytokines can induce synthesis of the acute-phase protein alpha1-antitrypsin in human articular chondrocytes.

Methods: Chondrocytes from human articular cartilage, cultured in agarose, were stimulated with IL-6-type cytokines.

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Heparan sulfate (HS) proteoglycans of bone marrow (BM) stromal cells and their extracellular matrix are important components of the microenvironment of hematopoietic tissues and are involved in the interaction of hematopoietic stem and stromal cells. Although previous studies have emphasized the role of HS proteoglycan synthesis by BM stromal cells, we have recently shown that the human hematopoietic progenitor cell line TF-1 also expressed an HS proteoglycan. Immunochemical, reverse transcriptase-polymerase chain reaction (RT-PCR), and Northern blot analysis of this HS proteoglycan showed that it was not related to the syndecan family of HS proteoglycans or to glypican.

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Proteoglycans of bone-marrow stromal cells and their extracellular matrix are important components of the haematopoietic microenvironment. Recently, several studies have indicated that they are involved in the interaction of haematopoietic stem and stromal cells. However, a detailed characterization of the heparan sulphate proteoglycans synthesized by bone-marrow stromal cells is still lacking.

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Proteoglycans of bone-marrow stromal cells and their extracellular matrix are important components of the microenvironment of haematopoietic tissues. Proteoglycans might also be involved in the interaction of haematopoietic stem and stromal cells. Recently, several studies have been reported on the proteoglycan synthesis of stromal cells, but little is known about the proteoglycan synthesis of haematopoietic stem or progenitor cells.

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The 5' region of the wound-inducible gene wun1, derived from potato, has been sequenced and analyzed for cis-acting elements important in controlling gene expression in transgenic tobacco plants. Different 5' deletion fragments were linked to the reporter gene beta-glucuronidase (GUS) as transcriptional fusions, and the expression of these chimeric genes was analyzed in leaf tissue. Sequences 111 base pairs upstream of the transcriptional start site were not able to drive the GUS expression over background levels, whereas sequences between -111 and -571 showed a slightly higher activity with equal levels of transcription in wounded and nonwounded tissue.

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Aging, aphidicolin, serum deprivation and cytochalasin B induce a decrease in the rate of DNA synthesis, an increase in cell flattening (cell surface increase) and an extension of the cytoplasmic microtubular complex (CMTC). Age and experimental conditions affect the protein content of the cell, but there is no relationship between cell morphology and cell protein content. Serum deprivation, aphidicolin and cytochalasin B are more effective on DNA synthesis and cytoplasmic actin complex (CAC) of late than of early fibroblasts.

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