Biomedical subjects

S Scheid

Publications and source records attributed to S Scheid.

7 recordsLinked to original sources

PubMed2004

DNA microarray technology and its applications in dermatology.

The use of DNA microarray technology in biomedical research has dramatically increased during the past years. In the present report, we provide an overview on the basic DNA microarray technology and biostatistical methods for gene expression analysis. A focus is then put on its applications in dermatological research. In recent years, a series of gene expression studies have been performed for various dermatological diseases, such as malignant melanoma, psoriasis and lupus erythematosus. These analyses have identified interesting target genes as well as putative disease susceptibility loci. However, further functional studies will be needed for a more complete understanding of the pathogenesis of these diseases. This may be performed by means of the recently developed RNA interference technology. Besides its role in large-scale gene expression studies, DNA microarray technology has proved to be a valuable tool for genomic screens of genetic alterations, e.g. single nucleotide polymorphisms. These play a role in tumour development and progression, and also function as genetic markers for disease susceptibility. Taken together, DNA microarray technology opens enormous perspectives for dermatologists. It may help us understand the complex pathogenesis of a wide variety of dermatologic diseases and identify their genetic background.

Cell Differentiation↗

PubMed1998

Quality of IL-3 and G-CSF-mobilized peripheral blood stem cells in patients with early chronic phase CML.

Coexistence of Philadelphia chromosome (Ph)-negative, primitive hematopoietic progenitor cells with their malignant counterparts in chronic myelogenous leukemia (CML) has been reported. As most of the Ph-negative progenitor cells do not express the HLA-DR antigen, selection of them might be possible. Peripheral blood progenitor cells (PBPC) from eight early chronic phase (CML) patients were mobilized by ICE chemotherapy followed by simultaneous administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and recombinant human interleukin 3 (rhIL-3). PBPCs were collected by leukapheresis in the early phase of hematopoietic recovery after chemotherapy, CD34 selected and cultured in vitro. The content of Ph chromosome-positive cells in leukapheresis products as well as after CD34 enrichment and after in vitro culture was analyzed by interphase fluorescence in situ hybridization (FISH) and RT-PCR. The percentage of Ph chromosome-positive PBPC was reduced after each purification step in almost all samples. A substantial number of PBPC samples were negative for the bcr/abl mRNA rearrangement as analyzed by RT-PCR. The present study demonstrates the feasibility of mobilizing Ph-negative PBPC during the early phase of hematopoietic recovery after ICE chemotherapy and simultaneous administration of rhIL-3 and rhG-CSF.

Adult↗

PubMed1991

Effects of chemical form and dosage on the incorporation of selenium into tissue proteins in rats.

We investigated the incorporation of Se into the proteins of liver and muscle, the two main Se pools, during replenishment of Se-deficient rats with normal or large doses of 75Se-labeled selenite and selenomethionine, doses equivalent to the amounts ingested from a diet with 0.2 or 2 mg Se/kg. With the higher intake, Se levels were elevated. More Se was retained from selenomethionine than from selenite. After separation of the labeled proteins, it was apparent that the higher tissue Se contents were mainly due to nonspecific incorporation into a large number of proteins. We observed no differences between the two chemical forms with regard to the formation of the specific selenoproteins. The 10-fold increase in the Se supply led to a relatively small rise in the levels of these compounds. The results indicate that after ingestion of normal amounts of selenite nearly all of the element is present in the specific selenoproteins. With increasing doses a part is also incorporated nonspecifically into numerous other proteins. In the case of selenomethionine, a part of the element follows the same metabolic pathways, but a percentage is also deposited directly and nonspecifically into proteins in place of methionine.

Animals↗

PubMed1990

Subcellular distribution of selenoproteins in the liver of the rat.

After in vivo labeling with [75Se]selenite, the intracellular distribution of selenoproteins in the liver was investigated in selenium-adequate and selenium-deficient rats. In the subcellular fractions, which were obtained by differential centrifugation, the proteins were separated by means of SDS-PAGE and the selenium compounds were identified via their 75Se activity. In this way twelve selenium-containing proteins or protein subunits with molecular weights between 12,100 and 75,400 were found. Glutathione peroxidase was concentrated in the cytosol and in the mitochondria. With the newly detected selenoproteins, some were enriched in the cytosol, one was mainly found in the nuclear fraction and some, which were present mainly in the mitochondrial and microsomal fractions, are most probably membrane-bound. In the liver of selenium-depleted rats the selenium administered was used predominantly to restore the levels of some of the newly found selenoproteins, while in the liver of selenium-adequate animals most of the selenium retained was incorporated into the glutathione peroxidase. The differences in the distribution among the subcellular fractions and the specific incorporation of the element in selenium deficiency into certain compounds suggest that there are several metabolic pathways for selenium and that the selenoproteins are involved in several different processes of intracellular metabolism.

Animals↗

PubMed1988

Evidence for specific selenium target tissues and new biologically important selenoproteins.

After in-vivo labeling with [75Se]selenite the Se-containing proteins present in rat tissues were investigated by means of SDS-polyacrylamide gel electrophoresis. Thirteen Se-containing proteins or protein subunits with relative molecular weights of 12,100, 15,600, 18,000, 19,700, 22,200, 23,700, 27,800, 33,300, 55,500, 59,900, 64,900, 70,100 and 75,400 were detected in the tissue homogenates. The protein with the molecular weight of 23,700 was the subunit of glutathione peroxidase, which is the only selenoprotein so far known to have biological functions in animals. Most of these proteins were found in all tissues investigated but one was only detected in the testes and the spermatozoa and one was present mainly in the thyroid. With inadequate selenium intake there was a priority supply of the element to the brain, the reproductive and the endocrine organs, and at a molecular level to Se-containing proteins other than glutathione peroxidase. The results suggest important biological functions of these selenoproteins, especially in the specific target tissues.

Animals↗

PubMedDate not supplied

Combination of neutron activation analysis, tracer techniques, and biochemical methods in the investigation of selenium metabolism.

In several studies on rats, the metabolism of selenium was investigated. The quantitative determination of the element was carried out by instrumental neutron activation analysis. For in vivo tracer experiments, 75Se-labeled selenium compounds were used. In addition to these methods, procedures for the measurement of the selenoenzyme glutathione peroxidase, and for the investigation of other selenoproteins, were applied. In this way, information on the specific pools and sites of action of the element, on biologically important selenoproteins and the regulation of the selenium metabolism, was obtained.

Animals↗

PubMedDate not supplied

Bcl-2 mRNA-targeted ribozymes: effects on programmed cell death in chronic myelogenous leukemia cell lines.

We used synthetic RNA transcripts to prove the cleavage capability of ribozymes targeted against bcl-2-related RNAs. No cleavage occurred when control oligonucliotides were used. To assess the functional role of the specific ribozymes in chronic myelogenous leukemia (CML) cell lines we cultured K562, BV173, and Daudi cells for 48 h after lipofection with 10 microM oligonucleotide. An increase in apoptotic cells, dependent on ribozyme specificity, was shown in BV173 cells. This finding was underlined by the typical morphological changes, but there is no correlation with regard to the level of bcl-2 protein expressed. Though bcl-2 appears to interfere with cell death in myeloid cells, bcl-2-targeted ribozymes do not induce programmed cell death (PCD) by reducing bcl-2 protein levels, but rather by a presently unknown mechanism.

Apoptosis↗