Serum albumin

About: Serum albumin is a research topic. Over the lifetime, 16337 publications have been published within this topic receiving 516395 citations. The topic is also known as: blood albumin & ANALBA.

Erythrocytes serve as a reservoir for cellular and extracellular sphingosine 1-phosphate

Abstract: Sphingosine 1-phosphate (S1P) in blood is phosphorylated, stored, and transported by red blood cells (RBC). Release of S1P from RBC into plasma is a regulated process that does not occur in plasma- or serum-free media. Plasma fractionation and incubations with isolated and recombinant proteins identified high density lipoprotein (HDL) and serum albumin (SA) as non-redundant endogenous triggers for S1P release from RBC. S1P bound to SA and HDL was able to stimulate the S1P(1) receptor in calcium flux experiments. The binding capability of acceptor molecules triggers S1P release, as demonstrated with the anti-S1P antibody Sphingomab. More S1P was extracted from RBC membranes by HDL than by SA. Blood samples from anemic patients confirmed a reduced capacity for S1P release in plasma. In co-cultures of RBC and endothelial cells (EC), we observed transcellular transportation of S1P as a second function of RBC-associated S1P in the absence of SA and HDL and during tight RBC-EC contact, mimicking conditions in tissue interstitium and capillaries. In contrast to S1P bound to SA and HDL, RBC-associated S1P was significantly incorporated by EC after S1P lyase (SGPL1) inhibition. RBC-associated S1P, therefore, has two functions: (1) It contributes to the cellular pool of SGPL1-sensitive S1P in tissues after transcellular transportation and (2) it helps maintain extracellular S1P levels via SA and HDL independently from SGPL1 activity.

Effect of Oxidative Stress on the Structure and Function of Human Serum Albumin

Abstract: Purpose. Human serum albumin (HSA) was mildly oxidized by a metal–catalyzed oxidation system (MCO–HSA), chloramine–T (CT–HSA) or H2O2 (H2O2–HSA), and the effects of these treatments on the structural, drug–binding and esterase–like properties were studied. Methods. Protein conformation was examined by calorimetric, chromatographic, electrophoretic and spectroscopic techniques. Drug binding was studied by ultrafiltration method, and esterase–like activity was determined using p–nitrophenyl acetate as a substrate. Results. Far–UV and near–UV CD spectra indicated that significant structural changes had occured as the result of treatment with MCO–HSA and CT–HSA but not with H2O2–HSA. However, SDS–PAGE analysis does not provide precise information on gross conformational changes such as fragmentation, cross–linking and SDS–resistant polymerisation. The results of differential scanning calorimetry, the fluorescence of the hydrophobic probe 1,1–bis–4–anilino–naphthalene–5,5–sulfonic acid and the elution time from a hydrophobic HPLC column indicated that MCO–HSA and CT–HSA in particular, have a more open structure and a higher degree of exposure of hydrophobic areas than unoxidized HSA. In all cases, high–affinity binding of warfarin remained unchanged for all the oxidized HSAs. However, high–affinity binding of ketoprofen to CT–HSA and, especially, MCO–HSA was diminished. In addition, the esterase–like activity of these proteins were all decreased to the same low level. Conclusions. Mild oxidation of HSA has no detectable effect on the binding of drugs to site I in subdomain IIA. In contrast, both the ligand binding property of site II and the esterase–like activity of oxidized HSAs are decreased, most probably due to conformational changes in subdomain IIIA.

Association between tumor necrosis factor in serum and cachexia in patients with prostate cancer

Abstract: The present study was undertaken to evaluate the relationship between serum tumor necrosis factor (TNF) and cachexia in patients with prostate cancer TNF levels were determined in 110 serum samples from prostate cancer patients by an enzyme immunoassay Serum TNF activity was positive in 76% of the patients with relapsed disease, whereas only 11% of the untreated patients and 0% of the patients in remission as a result of endocrine therapy were positive The serum total protein and albumin levels, hemoglobin levels, and body mass index of the patients with elevated serum TNF levels were significantly lower (P < 005) than the corresponding values in patients with undetectable serum TNF levels The serum TNF levels of patients with serum albumin levels of <35 g/dl, serum total protein levels of <70 g/dl, hemoglobin levels of <110 g/dl, and a body mass index of <21 kg/m2 were significantly higher (P < 005) than the values in their respective counterparts There was a significant correlation between the detectability of serum TNF and performance status (P < 005) Patients with elevated serum TNF levels had a significantly higher mortality rate (P < 005) than those with undetectable serum TNF levels These findings suggest that TNF may be one of the factors contributing to the complex syndrome of cachexia in patients with prostate cancer