Showing papers on "Bovine serum albumin published in 1973"

Interpretation of serum calcium in patients with abnormal serum proteins

Abstract: Two hundred consecutive specimens received in this laboratory for "liver function tests" showed a wide range of abnormal protein concentrations. Calcium concentration correlated closely with albumin (r = 0.867) but less closely with total protein (r = 0.682). A simple formula for adjusting calcium concentration was derived from the regression equation of calcium on albumin. Adjusted calcium = calcium - albumin + 4.0, where calcium is in mg/100 ml and albumin in g/100 ml.Low calcium concentrations were found in 49 (24.5%) and raised concentrations in six (3%) of the 200 blood specimens taken for liver function tests. After adjustment, the 95% limits of the observed range were identical with the 95% limits of the normal range determined in this laboratory. Unlike adjustments based on total protein or specific gravity, the adjustment on albumin in 39 specimens which showed hypergammaglobulinaemia on electrophoresis gave normal calcium concentrations.

Protein Digestion in Human Intestine as Reflected in Luminal, Mucosal, and Plasma Amino Acid Concentrations after Meals

Abstract: Normal human volunteers were intubated with either aspiration tubes or a biopsy capsule placed in the small intestine. The subjects were then fed a test meal containing 50 g of purified bovine serum albumin which served as the model dietary protein. Electrophoretic analysis of intestinal fluids showed that for at least 4 h the fed albumin was detectable in jejunal and ileal fluids. On separate occasions, subjects were fed the same meal without the protein. No protein was detected in intestinal fluids when the protein-free meal was fed. After the protein-rich meal, total concentrations of measured free and peptide amino acids rose from 3.21 to 29.29, and 15.94 to 117.97 mumol/ml, respectively, (P values < 0.02) in the jejunum. Similarly, total concentrations of measured free and peptide amino acids rose from 5.45 to 19.74, and 13.59 to 65.39, respectively, (P values < 0.05) in the ileum. In contrast, concentrations of free and peptide amino acids in intestinal fluids did not increase after the protein-free meal. While intracellular concentrations of amino acids in the jejunal mucosa did not show significant changes, plasma concentrations of each individual free amino acid were increased after the protein-rich meal and were either decreased or unaltered after the protein-free meal. The amino acid composition of the fed protein was reflected in the increases in intraluminal and plasma concentrations of individual amino acids after the protein-rich meal. It is concluded that after the ingestion of a test meal containing a substantial amount of protein which is within the usual range of dietary intake; (a) the exogenous protein is the principal source of the increased free and peptide amino acids in the intraluminal contents and in the plasma; (b) there are greater amounts of amino acids present as small peptides than in the free form in the gut lumen; (c) the ingested protein can be recovered as late as 4 h both in the jejunum and in the ileum.

Lipid A: chemical structure and biological activity.

Abstract: Further details of the chemical structure of lipid A of Salmonella have been evaluated. It was found that pyrophosphate bridges interlink (3-1,6-linked glucosamine disaccharide units, which are esterified by lauric, palmitic, and 3-D-myristoxymyristic acid and which are substituted at the amino groups by 3-D-hydroxymyristic acid. Lipid A is the biologically active component of lipopolysaccharides. Free lipid A, solubilized by complexing with bovine serum albumin, exhibits strong endotoxic activity in a number of biological tests. Lipid A exhibits immunogenic properties when suitably exposed on the bacterial surface. Immunization of rabbits with lipid A leads to the production of specific antibodies to lipid A that are capable of cross-reacting with a large variety of lipopolysaccharides.

The importance of serum albumin and metabolic intermediates for capacitation of spermatozoa and fertilization of mouse eggs in vitro

Abstract: Summary. The acrosome reaction of epididymal spermatozoa and fertilization in vitro of mouse eggs in chemically defined media without tissue fluid were investigated. About 8 to 10% of motile spermatozoa lost their acrosome but no eggs were penetrated when the spermatozoa and eggs were incubated in a basic medium (modified Krebs-Ringer bicarbonate solution containing glucose) for 5 to 7 hr. Addition of a single metabolic intermediate, such as sodium oxaloacetate or sodium pyruvate, to the basic medium increased the proportion of motile spermatozoa without an acrosome (19 to 34%) and the proportion of eggs penetrated (3\m=.\2 to 25\m=.\5%). Incubation of spermatozoa and eggs in the basic medium containing serum albumin of various species caused a further increase in the proportion of motile spermatozoa without an acrosome (50 to 65%) and in that of penetrated eggs (60\m=.\7 to 86%). The best medium for sperm capacitation and fertilization of mouse eggs in vitro, however, was the basic medium containing bovine serum albumin, sodium lactate and sodium pyruvate. The time required for sperm capacitation was 1 hr in this medium, and 2 hr in the medium containing only serum albumin. Certain components present in the oviducal fluid and in the cumulus egg clots, probably similar to serum albumin and sodium lactate or sodium pyruvate, appeared to be beneficial for the capacitation of spermatozoa and fertilization of eggs. It was concluded that serum albumin, sodium lactate and sodium pyruvate can be substituted for tissue fluid in the induction of capacitation of spermatozoa and fertilization of mouse eggs in vitro.

Interaction of human thymus-derived and non-thymus-derived lymphocytes in vitro. Induction of proliferation and antibody synthesis in B lymphocytes by a soluble factor released from antigen-stimulated T lymphocytes.

Abstract: Relatively pure populations of human T and B lymphocytes were obtained from blood and tonsils using density gradient centrifugation in bovine serum albumin. Antigen alone was incapable of triggering the B lymphocyte into blast transformation or to secrete antibody. However, supernatants from tetanus toxoid-stimulated T cells obtained from immune donors contained a factor mitogenic for B lymphocytes. 50–60% of B cells responded to this lymphocyte mitogenic factor (LMF) by proliferation, loss of C3 reactivity, and change to a secretory state. LMF-stimulated B cells exhibited a three- to fivefold increase in protein secretion and a six- to eightfold increase in gamma G globulin secretion. De novo secreted IgG had specificity directed to the tetanus toxoid present in the LMF containing T-cell supernatants. This was confirmed by an increase in the number of indirect plaque-forming cells to tetanus toxoid-coated sheep red blood cells after stimulation of B cells with LMF. It is proposed that in the course of the response to a previously encountered protein antigen, sensitized human T cells emit a signal in the form of a soluble product that, together with antigen, triggers B cells into division and antibody secretion. The experimental model utilized can be adapted to study human T-B cell cooperation under various conditions in normal individuals and in individuals with immunodeficiency diseases.

Resolution of DL-Tryptophan by Affinity Chromatography on Bovine-Serum Albumin-Agarose Columns

Abstract: Bovine-serum albumin, known to have antipodal specificity in the binding of tryptophan, was selected as the affinity chromatographic matrix for the attempted chromatographic resolution of DL-tryptophan. Complete resolution was accomplished when Dl-tryptophan was chromatographed on bovine-serum albuminsuccinoylaminoethyl-Sepharose.

Mass production of human interferon in diploid cells stimulated by poly-I:C.

Abstract: Summary The production of interferon by human diploid cells stimulated by poly-I:C can be increased by pretreatment of the cells with interferon (priming effect). Large amounts of interferon (30000 units/ml) can be obtained by combining priming with a superinduction schedule adapted from that described for rabbit kidney cultures (Tan et al. 1970; Vilcek & Ng, 1971). Human plasma protein could replace bovine serum albumin in the production medium.

Conjugates of immunoglobulin G with different fluorochromes. II. Specific and non-specific binding properties.

Abstract: Conjugate fractions of IgG labelled with FITC, MRITC, RB200SC or RBITC were tested on different substrates and the resulting fluorescence was evaluated with the Ploem optical system. Immunofluorescence sensitivity was characterized by the end point of specific staining. Conjugate quality was further defined by a specificity interval factor. Non-specific staining end points exhibited an inverse semi-logarithmic correlation with the molar FITC/protein ratio, while the influence of this ratio on specific staining varied greatly between different conjugates. Best sensitivity, combined with a favourable specificity interval, was obtained for selected fractions of MRITC and RB200SC conjugates. An inconsistent tendency of such conjugate fractions to produce non-specific background staining was reduced by bovine serum albumin or by tissue powder adsorption. Several substrates were evaluated with regard to their usefulness in performance testing Carried out to determine the immunological specificity of conjugates. Reliable evidence of binding specificity was obtained by applying the conjugate absorbed in excess with the corresponding soluble antigen.

Characterization of the binding of benzodiazepines to human serum albumin

Abstract: The binding of eleven benzodiazepine derivatives to human serum albumin (HSA) was determined by means of sephadex gel filtration. The albumin binding of the substances was characterized by the percentage of bound drug, the binding constants k +, K 1 and m, the number of binding sites per albumin molecule, and the free binding energy. Under the conditions chosen in these experiments there seems to exist only one binding site of the same type for all investigated benzodiazepines at the HSA molecule. The affinities of the benzodiazepines to this binding site are very different. It is discussed which part of the benzodiazepine molecule represents the main binding group.

hydrolysis of beta-galactosides using polymer-entrapped lactase: A study towards producing lactose-free milk.

Abstract: A yeast lactase, Maxilact, was immobilized in crosslinked polyacrylamide using a bead-polymerization technique. The polymer beads obtained, containing the entrapped enzyme, were used for the preparation of lactose-free milk. The binding yield of the enzyme and residual enzymic activity in the “enzyme beads” were studied as a function of the amounts of monomeric acrylamide and cysteine and bovine serum albumin present as protecting agents in the monomer-enzyme solution prior to polymerization. A maximum of about 75% of the enzyme could be immobilized using a 20% (w/v) solution of acrylamide plus N, N′-methylenebis-acrylamide, whereas the highest activity quotient (bound to free) of about 60% was observed on using a 25% solution. The presence of cysteine increased the activity by up to 30% and that of serum albumin up to about 15%.

Pyrogenicity and Immunogenicity of Lipid A Complexed with Bovine Serum Albumin or Human Serum Albumin

Abstract: The lipid A component of bacterial lipopolysaccharides (endotoxins), when complexed to bovine serum albumin (BSA) or human serum albumin (HSA), was shown to be a potent pyrogen. Furthermore, rabbits could be protected against endotoxin fever by immunization with both lipid A·BSA and lipid A·HSA complexes. The results presented in this paper show that lipid A is responsible for the pyrogenic activity of endotoxins and their ability to induce pyrogenic immunity.

The Antibody-Antigen Reaction: A Visual Observation

Abstract: Rothen and Mathot (1) and later Vroman and Adams (2) have shown that the antibody-antigen reaction will take place at a liquid-solid interface, and that the results of this interaction can be detected by the use of an ellipsometer. This optical instrument measures the adsorption and rotation of plane polarized light incident on the surface in question and has a limiting sensitivity of much less than a monolayer of adsorbed protein. I have used this technique to study the adsorption of protein from a solution onto various surfaces, such as Nb, Ta, Ni, Au, In, and Si, and further to observe the kinetics of the subsequent reaction with antibodies (Giaver, I., in preparation). These studies confirm earlier findings that the adsorption of a globular protein such as bovine serum albumin (BSA) 1 and ovalbumin (OA) results in a monolayer about 30A thick while the reaction with appropriate antibodies increases the thickness of the layer to approximately 100A.

Biosynthesis of serum albumin in rat liver. Evidence for the existence of 'proalbumin'.

Abstract: 1. A protein(s) of rat liver (precipitated from soluble extracts of the microsomal fraction by anti-albumin) yields albumin after limited hydrolysis by trypsin. 2. Evidence that the product of limited tryptic hydrolysis is albumin, is based upon ion-exchange chromatography, electrofocusing and peptide `mapping'. 3. The albumin `precursor' is recognized by anti-albumin and is apparently not distinguished from albumin by anti-albumin. 4. A small peptide is liberated from the presumptive albumin precursor during limited tryptic hydrolysis. This peptide is labelled by arginine, but not by leucine, lysine or methionine. 5. These results support our previous suggestion based on kinetic evidence that the albumin-like protein(s), in the anti-albumin precipitate from rat liver, is an albumin precursor.

Determination of the Dissociation Constants of the Lysine Residues of Lysozyme by Proton-Magnetic-Resonance Spectroscopy

Abstract: Amino groups of a series of model compounds and proteins are methylated by reductive condensation with formaldehyde and borohydride to provide observable resonances for proton magnetic resonance experiments. The extent of methylation varies from 92% for ribonuclease A to 66% for bovine serum albumin. As observed by PMR difference spectroscopy, the conformation of most of these proteins is unaltered by the modification. Retention of native conformation by methylated lysozyme is also shown by enzymatic activity measurements and PMR observation of thermal denaturation. Resonances corresponding to each of the six Nɛ-dimethyllysine residues in methylated lysozyme are resolved at 270 MHz and titrated to obtain individual pK values. A correction factor of 0.6 pH units obtained from model compound studies is applied to obtain apparent pK values ranging from 10.1 to 10.7 for the ɛ-amino groups of lysozyme. Assignment of resonances to specific residues is accomplished using the selective broadening effect of Gd3-. These results indicate the utility of the N-dimethyl group for probing the environment of lysine residues in proteins.

Electrophoresis, Specific Protein Assays, or Both in Measurement of Plasma Proteins?

Abstract: Cumulative knowledge of the protein composition of plasma and newer techniques for specific analysis of proteins have made obsolete most flocculation tests, the albumin:globulin ratio, scanning diagrams, and most determinations of electrophoretic fractions. More clinically relevant information about the serum protein composition is obtained by critical visual evaluation of the protein bands obtained after electrophoretic separation of plasma or serum in nonadsorptive supporting media, if supplementary specific analysis is made of a small number of proteins such as albumin, orosomucoid, haptoglobins, ceruloplasmin, and the immunoglobulins of the three predominant classes

Liquid control solution

Abstract: A stable liquid control solution useful with dry reagent strips which strips are for determining whether or not glucose is present in blood or serum. The control solution comprising water, an antidiffusing agent and glucose. The antidiffusing agent may be selected from materials such as polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, dextran and bovine serum albumin. The control solution may also include adjuvants such as preservatives, common salts, dyes, colored latex particles, etc.