Effect Of Human Serum Albumin Research Articles

The Detection of Pyrogens in Blood Products Using an Ex Vivo Whole Blood Culture Assay

Induction of interleukin-6 (IL-6) secretion by whole blood cultures (WBC) was used as an in vitro assay system for pyrogen-induced inflammatory reactions. The assay system was very sensitive to Eschericia coli (E.coli) endotoxin (< 10 pg/ml). The potential pyrogenic effects of human serum albumin (HSA), Fibronectin (Fn) and stabilised human serum (SHS) solutions were analyzed using this system. None of the products assayed had an effect on the sensitivity of the WBC assay. Spike recovery studies with isolated endotoxin, gram positive and gram negative bacteria showed that none of the products had an effect on the spike recovery of these pyrogenic substances. Good correlations were found between the WBC assay and the rabbit assay for pyrogens for all the production batches tested. When these samples were analysed by the limulus amoebocyte lysate (LAL) assay, the LAL test gave anomalous results for 1 out of the 22 production batches tested. This batch gave a false negative result on the LAL assay and might be indicative of the inability of the LAL assay to detect pyrogens other than endotoxin.

Does Hemodilution Enhance or Compromise Blood Coagulation?

The reduction in oxygen-carrying capacity during hemodilution is well tolerated by most patients. However, hemodilution not only decreases O2transport capacity, but also may influence blood coagulation. Advanced hemodilution with crystalloids does not compromise blood coagulation and, with moderate hemodilution, even augmented blood coagulation may develop. In contrast, blood coagulation is compromised during hemodilution with colloids. The effect of human serum albumin and gelatin is relatively modest, but significantly more than during equivalent hemodilution with crystalloids. Dextran and hydroxyethyl starch compromise blood coagulation more. This results from reduction of factor VIII, a decrease in plasmatic coagulation, and an impairment of platelet function. For hydroxyethyl starch, molecular size and degree of substitution are crucial for the effect on blood coagulation, with hydroxyethyl starch (200,000/0.5) having the least effect. Furthermore, accelerated fibrin formation is observed during hemodilution with Dextran, hydroxyethyl starch, and gelatin with an altered fibrin structure. In vitro clot lysis is also increased with all colloids, but there are no reports on augmented in vivo fibrin degradation products. Besides the effect on intraoperative blood coagulation, the hemodynamic effectiveness, duration thereof, effect on microcirculation and edema formation, and, in particular, the effect on the hypercoagulable state in the postoperative period need to be considered in the choice of the replacement fluid during hemodilution and intraoperative blood loss.

Albumin inhibits neutrophil spreading and hydrogen peroxide release by blocking the shedding of CD43 (sialophorin, leukosialin).

Spreading of neutrophils on protein-coated surfaces is a pivotal event in their ability to respond to soluble, physiologic agonists by releasing large amounts of hydrolases and oxidants. Using neutrophils plated on serum-, fibrinogen- or fibronectin-coated surfaces, we investigated the effect of human serum albumin (HSA) on spreading-dependent neutrophil responses. HSA suppressed the respiratory burst of neutrophils in response to tumor necrosis factor-alpha (TNF), complement component C5a or formylated peptide, but not phorbol myristate acetate. HSA was suppressive only if added before the onset of the respiratory burst, and suppression was reversed when HSA was removed. Likewise, HSA selectively and reversibly inhibited TNF-induced cell spreading and the associated fall in cAMP. However, HSA did not hinder TNF-induced cell adherence to the same protein-coated surfaces. We investigated cell surface sialoproteins as modulators of cell spreading and as targets for the anti-spreading action of HSA. Oxidation of the cell surface with periodate followed by reduction with 3H-borohydride and immunoblotting with specific mAbs helped identify the predominant sialoprotein on human neutrophils as CD43 (sialophorin, leukosialin). Treatment of neutrophils with C. perfringens sialidase desialylated CD43, markedly enhanced the ability of the cells to respond to TNF by spreading and undergoing a respiratory burst, and antagonized the ability of HSA to inhibit these responses. TNF-treated, adherent neutrophils shed CD43, and this was blocked by HSA, but not by ovalbumin. Exogenous neutrophil elastase removed CD43 from the neutrophil surface. HSA blocked the actions of both sialidase and elastase on CD43. In contrast, ovalbumin did not block the action of sialidase on CD43, and HSA did not inhibit the ability of sialidase to hydrolyze a synthetic substrate. These results suggested that HSA might bind CD43. In fact, the extracellular portion of CD43 bound to HSA-Sepharose, but not to ovalbumin- or glycylglycine-Sepharose. Finally, two mAbs recognizing different epitopes on CD43 mimicked HSA's inhibitory effects on neutrophil function. Thus, HSA can dissociate attachment of neutrophils from spreading. This dissociation may help neutrophils migrate along a chemotactic gradient, while decreasing their release of oxidants. CD43, a long, rigid molecule with a markedly negative charge, antagonizes neutrophil spreading. HSA appears to inhibit spreading-dependent neutrophil functions by binding to CD43 and interfering with the ability of neutrophils to shed it.

Preparation and evaluation of temperature sensitive liposomes containing adriamycin and cytarabine

Temperature sensitive liposomes (TSL) containing adriamycin (ADM) and cytarabine (Ara-C) were prepared. ADM and Ara-C were selected as model compounds of amphiphilic and hydrophilic drug, respectively. Encapsulation efficiency of ADM entrapped into TSL was about twice greater than that of Ara-C. It might be due to different polarity of the drugs. Lipid compositions of TSL had no effect on the encapsulation efficiency of drugs. Thermal behavior of TSL using a differential scanning calorimetry (DSC) was also investigated. Phase transition temperature (Tc) of TSL was dependent on the lipid compositions of TSL.ADM broadened thermogram of TSL but Ara-C did not. However, Tc of TSL was not changed by any drug. Release rate of drugs was highly dependent on temperature. The release profile of ADM was similar to that of Ara-C. The maximum release rate of drugs from TSL was occurred at the near Tc and observed at 39–41°C for DPPC (Dipalmitoylphosphatidylcholine) only, 52–54°C for DSPC (Distearoylphosphatidylcholine) only, 41–43°C for DPPC and DSPC (3∶1), and 43–45°C for DPPC and DSPC (1∶1), respectively. Effect of human serum albumin (HSA) on the release rate of ADM was investigated. HSA had no significant effect on the release of ADM below Tc. However, ADM release from TSL was increased at the near and above Tc. The HSA-induced leakage of drug may result from the interaction of liposomal constituents with HSA structure at the near Tc. From the fact that the release profiles of ADM from freshly prepared TSL and stored TSL for 1 week at 4°C was not changed, the TSL was considered to be stable for at least 1 week at 4°C. Based on these findings, TSL may be useful to deliver drugs to preheated target sites due to its thermal behaviors.

Ionic binding, net charge, and Donnan effect of human serum albumin as a function of pH

The ionic activities and total molalities of sodium, potassium, calcium, lithium, and chloride in a solution of human serum albumin were measured at different values of pH between 4 and 9. The same quantities were measured simultaneously in a protein-free electrolyte solution in membrane equilibrium with the albumin solution. Taking the residual liquid-junction potential and bias from unselectivity of the electrodes into account, we determined the own, bound, and net charges of albumin. Chloride was amply bound at low pH, and calcium at high pH. The varying charge of ions bound to albumin opposed the effect of acid or base on the net charge. All ions were distributed across the membrane according to the same electric potential difference, which equalled the Donnan potential. The high concordance between observation and theory favors the Donnan theory and furthermore implies that the electrodes are as accurate in a solution with albumin as in a protein-free solution.

Effect of albumin on adenylate cyclase receptor-related signal transduction of human peripheral blood mononuclear cells

In the present study we investigated in vitro the effect of human serum albumin (HSA) on receptor-stimulated cAMP production in isolated human peripheral blood mononuclear cells (PBMC). The cAMP production is strongly correlated with the pH of the medium during long incubations with albumin. Adenylate cyclase is stimulated by receptor agonists like histamine, forskolin, prostaglandin E 2 and the β-adrenergic agonist isoprenaline, in the presence or absence of HSA. This protein, at concentrations above 0.1%, dose-dependently inhibits both basal and agonist-stimulated cAMP levels in PBMC. In the presence of 0.5% HSA a significant reduction of 30–60% (cell batch dependent) is induced, a reduction which is not incubation time dependent. Washing the cells after a period of incubation with 2% HSA does not reverse the HSA-induced cAMP inhibition. Oleic acid-evoked conformational changes in HSA were not capable of influencing the inhibition processes of HSA on the isoprenaline-stimulated cAMP production. Structure-controlled interactions between HSA and membrane or adenylate cyclase are therefore unlikely. Bovine serum albumin and chicken albumin had different effects upon the agonist-stimulated cAMP production as compared with HSA. At this moment no explanation for this behavior can be provided. The findings indicate that albumin may inhibit nonspecifically cAMP production in PBMC and possibly influences membrane-controlled processes.

Phosphoinositide turnover in human platelets is stimulated by albumin

The effect of human serum albumin (HSA) on the hydrolysis of phosphatidylinositides in human platelets labeled with myo( 3H)inositol was studied. Incubation of platelets with HSA (4 gm/dl) for 10 seconds increased IP 2 and IP 3 by 169% and 217% respectively. 93% of IP 3 accumulated within the first 10 seconds. This effect was also shared by bovine serum albumin, although no changes in IP 3 levels occured with ovalbumin. All albumin species used induced 45Ca +2 release from platelets irrespective of its effect on IP 3 accumulation. These findings indicate that albumin may function in biological systems by inducing intracellular signaling.

Effects of human serum albumin on absorption and fluorescence spectra of dyes related to Chrome Azurol S.

Effects of human serum albumin on absorption and fluorescence spectra of dyes related to Chrome Azurol S.

Stabilizing effect of epsilon-aminocaproic acid on allergenic extracts

The effect of ϵ-aminocaproic acid (EACA) on the degradation of an aqueous Lolium perenne extract was studied by intracutaneous tests and by RAST inhibition. Extracts for skin testing stored at 4 ° C for 12 months and at 37 ° C for 6 weeks were significantly protected from degradation by addition of 0.1 mol/L of EACA before storage. Extracts were stored for RAST inhibition at 4 ° C for 6 months and at 37 ° C for 7 days. Shelf life was twofold to threefold increased when 0.1 mol/L of EACA was added to the dilution medium. EACA also protected the extracts from the effect of freezing and thawing. Comparison with the effect of human serum albumin indicated a rather short activity of human serum albumin, whereas the effect of EACA lasted longer. It is suggested that EACA can be used to increase the stability of aqueous allergen extracts for skin testing and for hyposensitization therapy.

Kinetic studies on the reduction of iron(III)deuteroporphyrin-human serum albumin complex with dithionite ion

The effects of human serum albumin (HSA) on the rate of dithionite reduction of iron(III)deuteroporphyrin (iron(III)Dp) have been investigated in order to further characterize the porphyrin binding site and the changes manifested in this site under various conditions. These studies were performed under pseudo-first-order conditions, and in the presence of carbon monoxide as a “trapping agent” for the reduced iron(II)porphyrin. The rate of reduction of the free iron(III)Dp in phosphate buffer at pH 7.4 follows second-order kinetics with a rate constant (4.2 × 10 9 m −1 s −1) suggestive of a diffusion-controlled process. A six-orders of magnitude decrease in the rate of reduction was observed with iron(III)Dp was complexed with HSA. This result is consistent with HSA-bound porphyrin being less accessible to the aqueous environment. Additional studies demonstrated that both pH and anions induce various alterations in the complex that are reflected in the rate of reduction of iron(III)porphyrin.

Effect of serum albumin on siderophore-mediated utilization of transferrin iron.

The effect of serum and serum proteins on enterobactin- and aerobactin-mediated utilization of transferrin iron has been investigated. Serum was found to impede transfer of iron from iron transferrin to enterobactin and from [55Fe]ferric enterobactin to cells of Escherichia coli BN3040 Na 1R iuc . In contrast, serum had essentially no effect on the rate of these reactions mediated by aerobactin. Three purified serum proteins, human serum albumin, bovine serum albumin, and human immunoglobulin, were comparable to human serum in their selective ability to interfere with the transfer of 55Fe from [55Fe]ferric enterobactin to E. coli BN3040 Na 1R iuc . The inhibitory effect of human serum albumin on the enterobactin-mediated transfer of iron from [55Fe]transferrin was enhanced by preincubation of the protein with the siderophore. Pretreatment of the bacterial cells with human serum albumin did not affect the rate of utilization of siderophore iron. A linear, reciprocal relationship was found to hold for human albumin concentration vs. the first-order rate constant ( kobsd ) for the velocity of iron transfer from iron transferrin to enterobactin. Binding of serum albumin to enterobactin increased the intensity of the near-ultraviolet absorption band of the siderophore and shifted it to longer wavelengths. The stoichiometry of binding to human and bovine serum albumins was established as 1:1, and the binding constant for both enterobactin and ferric enterobactin was estimated to be in the range 1 X 10(4)-1.2 X 10(5) M-1. These results indicate that serum albumin may act synergistically with other factors in the serum, such as transferrin, to limit iron supply and in this way restrict the growth of invading microorganisms.

The polymorphonuclear leukocyte chemotactic response to Bacteroides melaninogenicus. I. Effect of human serum albumin.

Neutrophil movement is an important mechanism in the defense against injury or infection. This study examined the in vitro effect of human serum albumin (HSA), normal and heat inactivated foetal calf serum, and Bacteroides melaninogenicus sonicates on human neutrophils using a modified Boyden chamber. The results indicate that sonicates of B. melaninogenicus in the absence of serum or HSA are not either chemotactic or chemokinetic. On the other hand, HSA is chemokinetic, but the addition of B. melaninogenicus sonicates appeared to mask this effect. The results would suggest that the effect of HSA be at least standardized in assessing the presence or absence of in vitro PMN chemotactic anomalies to plaque organisms in relation to periodontal disease.

Geometry of the human erythrocyte. I. Effect of albumin on cell geometry

The effects of albumin on the geometry of human erythrocytes have been studied. Individual red cells, hanging on edge from coverslips were photographed. Enlarged cell profiles were digitized using a Gradicon digitizer (Instronics Ltd., Stittsville, Ontario). Geometric parameters including diameter, area, volume, minimum cylindrical diameter, sphericity index, swelling index, maximum and minimum cell thickness, were calculated for each cell using a CDC 6400 computer. Maximum effect of human serum albumin was reached at about 1 g/liter. Studies of cell populations showed decreases in mean cell diameter of up to 6%, area 6%, and volume 15%, varying from sample to sample. The thickness of the rim was increased while that at the dimple was decreased. Studies of single cells showed that area and volume changes do not occur equally in all cells. Cells with lower sphericity indices showed larger effects. In the presence of albumin, up to 50% of the cells assumed cup-shapes (stomatocytes). These cells had smaller volumes but the same area as biconcave cells. Mechanical agitation could reversibly induce biconcave cells to assume cup shapes without area or volume changes. Experiments with de-fatted human albumins showed that the presence of bound fatty acids in varying concentrations does not alter the observed effects. Bovine serum albumin has similar effects on human erythrocytes as human serum albumin.

Effect of human serum albumin on the glucose metabolism of isolated rat diaphragm and its response to insulin.

The effect of human serum albumin prepared by Cohn method 6 on the glucose metabolism of isolated rat diaphragms was studied. In the absence of insulin 5 per cent albumin slightly inhibited glucose uptake and lactate production but not glycogen synthesis. Albumin partially inhibited the stimulatory effect of insulin on glucose uptake, lactate production and glycogen synthesis. The insulin antagonistic effect of 5 per cent albumin was due in part only to increased H+ ion concentration in the medium. Albumin (1.25 per cent) did not affect glucose utilization or lactate production with or without insulin. Albumin (5 per cent) alone slightly but significantly augmented the penetration of d-xylose into “intact” diaphragms. In the presence of insulin and albumin the space of distribution of d-xylose was significantly less than with insulin alone. The albumin preparations contained free fatty acids and citrate; however, the insulin antagonism of 5 per cent albumin could not be reproduced with palmitate or citrate. Following dialysis and lyophilization 5 per cent albumin assayed at controlled pH did not affect glucose uptake, lactate production or glycogen synthesis either in the presence or absence of insulin. The noninhibitory albumin was extracted with TCA-ethanol, dialyzed, lyophilized and assayed as above. It significantly inhibited the stimulatory effect of insulin on glucose uptake, lactate production and glycogen synthesis. It is suggested that several factors can be associated with albumin and antagonize the stimulatory effect of insulin on muscles in vitro. These factors will have to be separated and characterized before the biological significance of the “synalbumin antagonist” of insulin can be evaluated.

Observations on Albumin Metabolism in Nontropical Sprue and Effects of Human Serum Albumin or Gluten-restricted Diet Using Radioiodinated Human Serum Albumin and Metabolic Balance Studies.

s1 April 1963Observations on Albumin Metabolism in Nontropical Sprue and Effects of Human Serum Albumin or Gluten-restricted Diet Using Radioiodinated Human Serum Albumin and Metabolic Balance Studies.H. H. Scudamore, M.D., F.A.C.P., R. E. Sedlack, M.D., W. N. Tauxe, M.D., J. W. Rosevear, M.D., Ph.D.H. H. Scudamore, M.D., F.A.C.P.Search for more papers by this author, R. E. Sedlack, M.D.Search for more papers by this author, W. N. Tauxe, M.D.Search for more papers by this author, J. W. Rosevear, M.D., Ph.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-58-4-726_3 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptThe metabolism of albumin in patients having nontropical sprue has been evaluated by means of I131-labeled human serum albumin and compared with that of healthy subjects. Studies were made of metabolic nitrogen and calcium balance and of fat intake and excretion. The sprue in the 12 patients investigated ranged from mild to extremely severe with hypo-albuminemia, edema, and hypocalcemia. The immediate response to non-labeled human serum albumin administered intravenously in 4 patients and the long-term response to a gluten-restricted diet were measured.The intravenously administered I131-labeled human serum albumin had a shortened survival or half-time in the plasma owing to... This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: Rochester, Minn. (CS) PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics 1 April 1963Volume 58, Issue 4Page: 726-727KeywordsBlood plasmaCalciumDietEdemaExcretionFatsHypocalcemiaSerum albumin Issue Published: 1 April 1963 PDF DownloadLoading ...