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Biomedical subjects

P Wulf

Publications and source records attributed to P Wulf.

9 recordsLinked to original sources
PubMed2001

Irradiated versus nonirradiated endothelial cells: effect on proliferation of vascular smooth muscle cells.

PURPOSE: Endovascular radiation therapy is a promising strategy for the prevention of restenosis. Radiation prevents proliferation of vascular smooth muscle cells, thereby reducing the incidence of restenosis, but may also affect the remaining endothelial cells. For this reason, a comparison was made between irradiated and nonirradiated endothelial cells and their effects on the proliferation of vascular smooth muscle cells in a coculture system was evaluated. MATERIALS AND METHODS: A coculture system was used, in which both endothelial cells and vascular smooth muscle cells were grown on opposite sides of a semipermeable membrane. After a period of growth arrest, the proliferation of vascular smooth muscle cells was measured during four subsequent days. RESULTS: The presence of endothelial cells stimulated the proliferation of vascular smooth muscle cells during the first days of analysis but had an inhibitory effect during the subsequent days (P <.5). gamma-irradiation of endothelial cells resulted in a complete blockage of the proliferation of these cells. However, irradiated endothelial cells affected the proliferation of vascular smooth muscle cells in coculture in a fashion comparable to nonirradiated endothelial cells (P >.5). CONCLUSION: The results suggest that, in endovascular radiation therapy, irradiation of endothelial cells does not change their effects on the proliferative behavior of vascular smooth muscle cells.

Animals↗
PubMed2001

Modelling of full-scale wastewater treatment plants with different treatment processes using the Activated Sludge Model no. 3.

In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; Hildesheim: simultaneous denitrification with EBPR; Duderstadt: intermediate denitrification with EBPR). Informations regarding the choice of kinetic and stoichiometric parameters will be given.

Calibration↗
PubMed1999

Embryonic expression of epithelial membrane protein 1 in early neurons.

Epithelial membrane protein 1 (EMP1) is a member of the peripheral myelin protein 22 (PMP22) family. This family is best known for the crucial contribution of PMP22 to the development and maintenance of the peripheral nervous system (PNS). PMP22 is widely expressed, with highest levels in myelinating Schwann cells, and mutations affecting the PMP22 gene lead to PNS-restricted neuropathies. We have investigated the spatio-temporal distribution of EMP1 and compared it to that of PMP22. We found that EMP1 and PMP22 mRNA are most conspicuously expressed in the prenatal mouse brain during neurogenesis. In the developing forebrain, we localized EMP1 mRNA and protein to the first set of neurons that are generated and leave the ventricular zone to form the preplate. Later in development, EMP1 was found in derivatives of the preplate, the marginal zone and the subplate. Reduced expression was observed in the newly generated cortical plate neurons. In other parts of the developing CNS and PNS, EMP1 was also detected in early neurons and along the initial fiber tracts. Furthermore, EMP1 was highly expressed by immature neurons in embryonal dorsal root ganglia-explant cultures and in neuroectodermal differentiated P19 cells. While PMP22 functions mainly in Schwann cell growth and differentiation, the spatio-temporal localization of EMP1 suggests a role in neuronal differentiation and neurite outgrowth.

Amino Acid Sequence↗
PubMed1999

Characterization of peripheral myelin protein 22 in zebrafish (zPMP22) suggests an early role in the development of the peripheral nervous system.

Peripheral myelin protein 22 (PMP22) is a component of compact myelin of the peripheral nervous system (PNS). Mutations affecting PMP22 are associated with hereditary neuropathies in humans and rodents. Although mammalian PMP22 is expressed in several tissues, the disease pathology is restricted to the PNS. We describe the characterization of a PMP22-related cDNA from zebrafish and the distribution of its cognate mRNA. Phylogenetic considerations and mRNA expression in cranial nerves are consistent with the interpretation that the encoded protein is the orthologue of mammalian PMP22. In situ hybridization analysis during development showed zebrafish PMP22 expression in embryonic sclerotome cells, in neural crest cells, and in migratory derivatives of both populations. Based on this specific expression pattern prior to the onset of myelination, we hypothesize that zebrafish PMP22 may play a role in early PNS development and that disturbance of such functions may contribute to the PNS-restricted defects caused by mutations in the mammalian PMP22 gene.

Amino Acid Sequence↗
PubMed1996

Identification and characterization of a cDNA and the structural gene encoding the mouse epithelial membrane protein-1.

The PMP22/EMP/MP20 gene family includes four closely related proteins, peripheral myelin protein-22 (PMP22), epithelial membrane protein-1 (EMP-1), epithelial membrane protein-2 (EMP-2), and epithelial membrane protein-3 (EMP-3), which share amino acid identities ranging from 33 to 43%. In addition, the lens-specific membrane protein MP20 represents a more distant relative. Functionally, this family of proteins is likely to play important roles in the control of cell proliferation, cell differentiation, and cell death. In particular, mutations affecting the PMP22 gene are responsible for various hereditary peripheral neuropathies in humans and mice. We report the isolation and characterization of a mouse EMP-1 cDNA and the corresponding emp-1 gene. Mouse EMP-1 displays 93% amino acid identity to rat EMP-1 and 39% identity to mouse PMP22. The cDNA-predicted EMP-1 protein contains four putative membrane-associated domains and can be N-linked glycosylated in vitro. EMP-1 is encoded by a single-copy gene with the positions of introns exactly conserved between emp-1 and PMP22, corroborating the hypothesis that both genes belong to the same family. Computer-predicted structural domains of EMP-1 are partially mirrored by the exon/intron structure of emp-1. Most interestingly, exon 4, which covers the potential second transmembrane domain, a small intracellular loop, and half of the third transmembrane domain, encodes the most highly conserved regions between the EMP-1 and PMP22 proteins and is also remarkably conserved in the MP20 gene, indicating some shared functional significance for this module in the PMP22/EMP/MP20 family.

Amino Acid Sequence↗
PubMed1987

Cost accounting in health care: fad or fundamental?

The drastic changes in the environment affecting hospitals have caused management to look toward capturing and reporting cost information to make decisions. These decisions will, in part, shape the way hospitals continue to do business. This article focuses on the data requirements necessary to support product and operational management decisions facing today's hospitals. In addition, the difference in data needed to support product and operational management is explored.

Accounting↗