Search results for "Helium"
showing 10 items of 1689 documents
Role of oxoproline in the regulation of neutral amino acid transport across the blood-brain barrier.
1996
Regulation of neutral amino acid transport was studied using isolated plasma membrane vesicles derived from the bovine blood-brain barrier. Neutral amino acids cross the blood-brain barrier by facilitative transport system L1, which may allow both desirable and undesirable amino acids to enter the brain. The sodium-dependent amino acid systems A and Bo,+ are located exclusively on abluminal membranes, in a position to pump unwanted amino acids out. gamma-Glutamyl transpeptidase, the first enzyme of the gamma-glutamyl cycle, is an integral protein of the luminal membrane of the blood-brain barrier. We demonstrate that oxoproline, an intracellular product of the gamma-glutamyl cycle, stimulat…
Kinetics of thrombomodulin release and endothelial cell injury by neutrophil-derived proteases and oxygen radicals
2002
Thrombomodulin is a transmembranous glycoprotein of endothelial cells. In vitro it is a marker of endothelial cell injury. In vivo the levels of serum thrombomodulin are regarded as a parameter of activity in vasculitides. The latter are pathophysiologically determined by neutrophil-derived inflammation and endothelial cell injury caused by secretion of proteases and hydrogen peroxide. It was the objective of this study to determine whether thrombomodulin is only a late marker of advanced endothelial cell injury or whether it indicates also earlier stages of cell alterations. Over 24 hr endothelial cell cultures were incubated with hydrogen peroxide or the neutrophil proteases proteinase-3,…
Relative contribution of different l-arginine sources to the substrate supply of endothelial nitric oxide synthase
2011
In certain cases of endothelial dysfunction l-arginine becomes rate-limiting for NO synthesis in spite of sufficiently high plasma concentrations of the amino acid. To better understand this phenomenon, we investigated routes of substrate supply to endothelial nitric oxide synthase (eNOS). Our previous data with human umbilical vein (HUVEC) and EA.hy.926 endothelial cells demonstrated that eNOS can obtain its substrate from the conversion of l-citrulline to l-arginine and from protein breakdown. In the present study, we determined the quantitative contribution of proteasomal and lysosomal protein degradation and investigated to what extent extracellular peptides and l-citrulline can provide…
Dithiothreitol Treatment of Madin-Darby Canine Kidney Cells Reversibly Blocks Export from the Endoplasmic Reticulum but Does Not Affect Vectorial Tar…
1995
Addition of dithiothreitol (DTT) to the culture medium of Madin-Darby canine kidney (MDCK) cells blocks transport of newly synthesized gp80 (clusterin, apolipoprotein J), a soluble marker protein for apical exocytosis in this epithelial cell line. In cells treated with DTT during pulse labeling, gp80 is retained in the endoplasmic reticulum. After removal of the reducing agent, gp80 is posttranslationally oxidized and secreted at the apical surface of MDCK cell monolayers. This demonstrates that when folded and oxidized posttranslationally, gp80 can acquire a conformation that exhibits sorting signals for vectorial targeting. In the continuous presence of DTT, the transepithelial electrical…
Identification of metabolic enzymes in renal cell carcinoma utilizing PROTEOMEX analyses
2003
Abstract PROTEOMEX, an approach which combines conventional proteome analysis with serological screening, is a powerful tool to separate proteins and identify immunogenic components in malignant diseases. By applying this approach, we characterized nine metabolic enzymes which were differentially expressed in renal cell carcinoma (RCC) cell lines and compared their expression profiles to that of normal kidney epithelium cells. Four of these proteins, superoxide dismutase (SODC), triosephosphatase isomerase (TPIS), thioredoxin (THIO) and ubiquitin carboxyl-terminal hydrolase (UBL1) were further analysed for both their constitutive and interferon (IFN)-γ inducible protein expression pattern i…
Exosomes from metastatic cancer cells transfer amoeboid phenotype to non-metastatic cells and increase endothelial permeability: their emerging role …
2017
AbstractThe goal of this study was to understand if exosomes derived from high-metastatic cells may influence the behavior of less aggressive cancer cells and the properties of the endothelium. We found that metastatic colon cancer cells are able to transfer their amoeboid phenotype to isogenic primary cancer cells through exosomes, and that this morphological transition is associated with the acquisition of a more aggressive behavior. Moreover, exosomes from the metastatic line (SW620Exos) exhibited higher ability to cause endothelial hyperpermeability than exosomes from the non metastatic line (SW480Exos). SWATH-based quantitative proteomic analysis highlighted that SW620Exos are signific…
Proteomic characterization of the mucosal pellicle formed in vitro on a cellular model of oral epithelium
2020
The oral mucosal pellicle is a thin lubricating layer generated by the binding of saliva proteins on epithelial oral cells. The protein composition of this biological structure has been to date studied by targeted analyses of specific salivary proteins. In order to perform a more exhaustive proteome characterization of pellicles, we used TR146 cells expressing or not the transmembrane mucin MUC1 and generated pellicles by incubation with human saliva and washing to remove unbound proteins. A suitable method was established for the in vitro isolation of the mucosal pellicle by "shaving" it from the cells using trypsin. The extracts, the washing solutions and the saliva used to constitute the…
Ab initio limits of atomic nuclei
2019
We predict the limits of existence of atomic nuclei, the proton and neutron drip lines, from the light through medium-mass regions. Starting from a chiral two- and three-nucleon interaction with good saturation properties, we use the valence-space in-medium similarity renormalization group to calculate ground-state and separation energies from helium to iron, nearly 700 isotopes in total. We use the available experimental data to quantify the theoretical uncertainties for our ab initio calculations towards the drip lines. Where the drip lines are known experimentally, our predictions are consistent within the estimated uncertainty. For the neutron-rich sodium to chromium isotopes, we provid…
FVIII production by human lung microvascular endothelial cells
2006
While extrahepatic factor VIII (FVIII) synthesis suffices for hemostasis, the extrahepatic production sites are not well defined. We therefore investigated the ability of the human lungs to produce FVIII. Lungs from heart-beating donors who were declined for transplantation were perfused and ventilated in an isolated reperfusion model for 2 hours. A progressive accumulation of FVIII and von Willebrand factor (VWF) was recorded in the perfusion medium in 3 of 4 experiments. By contrast, factor V, fibrinogen, and immunoglobulin G (IgG) levels remained constant during the perfusion period, indicating that the accumulation of FVIII and VWF was not due to diffusion from the intercellular medium …
Relaxant and antiadrenergic effects of ranolazine in human saphenous vein.
2019
Abstract OBJECTIVES Ranolazine improves vascular function in animal models. We evaluate the effects of ranolazine on vascular function and adrenergic response in human saphenous vein. METHODS Rings from 53 patients undergoing coronary artery bypass grafting were mounted in organ baths. Concentration–response curves to ranolazine were constructed in rings precontracted with phenylephrine, endothelin-1, vasopressin, KCl and the thromboxane A2 analogue U-46619. In rings precontracted with phenylephrine, relaxation to ranolazine was tested in the absence and presence of endothelial factors inhibitors, K+ channel blockers and verapamil. The effects of ranolazine on frequency–response and concent…