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At least 19 recordsLinked to original sources
PubMed1979

Renin binding proteins in plasma. Binding of renin to some of the plasma protease inhibitors, to lipoproteins, and to a non-trypsin-binding unidentified plasma protein.

Renin is found in mouse plasma as high molecular weight forms, in addition to the fully active 40 000 dalton form. By using freshly 125 I-labelled 40 000 dalton pure submaxillary mouse renin, no binding to plasma proteins was demonstrable. However, unfolding and refolding of the labelled renin by guanidine facilitated binding to specific mouse and human plasma proteins. By using antibodies against individual human plasma proteins, the specific binding proteins were identified to be the plasma protease inhibitors: alpha2-macroglobulin, inter-alpha-trypsin inhibitor, alpha2-antithrombin. Binding was also demonstrated to alpha1- and beta1-lipoproteins, albumin and to a non trypsin binding unidentified plasma protein. No binding to 56 other tested proteins was demonstrable. It is concluded that the native 40 000 renin does not bind, but that a conformational change of the renin molecule most likely is necessary before binding occurs. It is discussed whether or not inactive or high molecular weight forms of renin in plasma are 40 000 renin bound to plasma protease inhibitors and lipoprotein.

Animals↗
PubMed1985

Quantitative measurement of the total, peroxyl radical-trapping antioxidant capability of human blood plasma by controlled peroxidation. The important contribution made by plasma proteins.

Plasma obtained from fasted humans has been analysed for total radical-trapping antioxidant content by subjecting it to controlled peroxidation using the thermal decomposition of water-soluble azobis (2-amidinopropane hydrochloride) at 37 degrees C to produce peroxyl radicals at a known, steady rate. It is found that the total radical-trapping antioxidant content is rather similar for the 7 subjects that have been tested and, furthermore, it is 10-20-times larger than the effect attributable to vitamin E alone. Although it is shown that urate and ascorbate augment the contribution from vitamin E, their contributions (21-34 and 0-2%, respectively) still leave 57-73% of the total antioxidant content unaccounted for. Evidence is presented to show that this previously unrecognized large reserve of antioxidant capacity is attributable to the plasma proteins.

Antioxidants↗
PubMed1991

Inactivation of viruses found with plasma proteins.

Plasma protein solutions such as albumin and intramuscular immune globulin have long histories of viral safety. Coagulation factor concentrates as traditionally manufactured frequently transmitted HBV, HCV, and HIV. Indeed, it is probable that every vial of concentrate contained infectious HCV. Modern coagulation factor concentrates have a greatly improved safety record arising, principally, from the implementation of virucidal procedures. It is interesting to note that the same methods that failed to substantially reduce NANBHV transmission in clinical studies are those that were found to inactivate less than 10(4) ID50 of HIV, HBV, and/or HCV in preclinical studies (Table 17-5). Implementation even of these methods nearly eliminated the transmission of HIV by coagulation factor concentrates. A summary of the results of the most successful procedures is given in Table 17-10. The results show 0/564 patients had evidence of HIV transmission, 6/151 patients had evidence of HBV transmission, and 2/301 patients had evidence of HCV transmission. As compared with those procedures described in Table 17-5, the greater kill of HIV, HBV, and NANBHV demonstrated preclinically, and the improved clinical results, are most notable. The data, examined in terms of units transfused, are presented in Figure 17-1. Since the average adult hemophiliac in the United States receives 80,000 units of clotting factor per year, the best of the concentrates show safety over the equivalent of at least 10-human-years of treatment. Are the best of today's coagulation factor concentrates safe from the transmission of HBV, NANBHV (including HCV), and HIV. Given the limited number of patients eligible for clinical studies, and the length, difficulty, and expense of such studies, the best answer comes from a knowledge of the initial virus load coupled with information regarding virus removal, serendipitous inactivation, and intentional sterilization. A recently completed analysis of these factors (Horowitz 1990) indicates that the best of the modern coagulation factor concentrates are likely to be as safe as albumin (Figure 17-2).

Blood↗
PubMed1991

Comparison of mononuclear cell proteins and plasma proteins before and during parturition by two dimensional electrophoresis.

Two dimensional electrophoresis is a technique whereby protein sources are organized by molecular weight and electrical charge on a polyacrylamide gel. To detect changes that may be associated with the onset of parturition, we compared electrophoresis patterns of mononuclear cell proteins and plasma proteins before and during active labor. Mononuclear cells and plasma were obtained from 5 pregnant volunteers. It appears that A-1 apolipoprotein, identified by Western Blot analysis, is increased in mononuclear cells during active labor. Conversely, a decrease in the concentration of A-1 apolipoprotein was seen in plasma during parturition. These "normal" protein patterns can now be compared with those observed in pathologic conditions including preterm labor and may allow early detection of disease by protein abnormalities before clinical signs and symptoms develop.

Blood Proteins↗
PubMed1989

Two-dimensional electrophoresis of the plasma proteins of alpacas and llamas: genetic polymorphism of alpha 1B-glycoprotein and three other proteins.

Plasma samples of alpacas and llamas were analysed by a simple method of two-dimensional (2-D) agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis, followed by general protein staining of gels. Genetic polymorphism in both species is described for alpha 1B-glycoprotein (alpha 1B) and three other unidentified proteins designated prealbumin (Pr), postalbumin 1 and 2 (Pa1 and Pa2). alpha 1B was identified by cross-reactivity with antisera for human and pig alpha 1B. Altogether, two alleles of Pr, two of Pa1, five of alpha 1B and three of Pa2 are described. Most of the alleles were present in alpacas and llamas. Alpacas showed a high degree of polymorphism at all four loci. Llamas showed considerable polymorphism at only the Pa1 and Pa2 loci. The theoretical probability of exclusion (PE) of an incorrectly assigned parent was estimated to be about 80% in each species by typing for the six polymorphic plasma proteins reported so far in these species. The given method of 2-D electrophoresis revealed no fixed differences in protein mobilities that discriminate between llamas and alpacas.

Alleles↗
PubMed1990

Tianeptine binding to human plasma proteins and plasma from patients with hepatic cirrhosis or renal failure.

1. The binding of tianeptine to human plasma, isolated plasma proteins, red blood cells and to plasma from patients with cirrhosis or renal failure was studied in vitro by equilibrium dialysis. 2. Tianeptine is highly bound to plasma (95%) at therapeutic concentrations (0.3-1 microM). No saturation of the binding sites was seen. 3. Human serum albumin (HSA) was shown to be mainly responsible for this binding (94%) with a saturable process characterized by one binding site with a moderate affinity (Ka = 4.2 x 10(4) M-1) and a non-saturable process with a low total affinity (nKa = 1.2 x 10(4) M-1). 4. Like many basic and amphoteric drugs, tianeptine showed a saturable binding to alpha 1-acid glycoprotein (AAG) with one site and a moderate affinity (Ka = 3.7 x 10(4) M-1). Its binding to lipoproteins and red blood cells (RBC) was weak and non-saturable. Over the range of therapeutic drug concentrations (0.3-1 microM), the unbound fraction in blood remains constant (4.5%). 5. Interactions were studied using non-esterified fatty acids (NEFA) at pathological concentrations; they altered tianeptine binding to plasma and to isolated HSA. Tianeptine seems to bind to a HSA site different from sites I (warfarin) and II (diazepam), but close to site II. It also shares the only basic-site on AAG. However, at therapeutic drug concentrations (0.3-1 microM), not all of these interactions occur. 6. The binding of tianeptine varied according to HSA, AAG and NEFA concentrations both in patients and healthy subjects. In patients with chronic renal failure having high NEFA concentrations the unbound fraction of tianeptine (fu) increased from 0.045 to 0.153 compared with normal (P less than 0.001). In cirrhotic patients, with relatively low HSA concentrations, the fu of tianeptine increased from 0.045 to 0.088 compared with normal (P less than 0.01). 7. Multiple regression analysis of all of the data indicated that the fu of tianeptine was related significantly to HSA, NEFA and AAG concentrations, with a particularly strong correlation with NEFA concentrations. Therefore, variation of HSA and NEFA concentrations in patients on maintenance therapy may cause an increase of tianeptine fu.

Adult↗
PubMedDate not supplied

Influence of preoperative intravenous nutrition upon hepatic protein synthesis and plasma proteins and amino acids.

The influence of 3 and 7 days of preoperative intravenous nutrition (IVN) on the capacity for protein synthesis in liver and on concentrations of plasma proteins and amino acids were investigated in patients with gastrointestinal malignancy. Thirty patients with gastrointestinal neoplasms who had lost more than 5 kg of weight over 3 months were randomized into three groups to receive preoperatively: (a) no IVN, (b) IVN for 3 days (0.18 gN/kg/day as amino acid; 30 kcal/kg/day as glucose), or (c) IVN for 7 days. Free access to a hospital diet was available to all patients including 10 patients who had not lost weight who served as controls. In the three groups of patients who had lost weight, median transferrin and fibronectin were lower than for controls, whereas other proteins and amino acids were comparable. After feeding, samples of liver were obtained peroperatively and the potential rates of protein synthesis were calculated from the in vitro incorporation of (14C)-leucine, into protein. Preoperative IVN significantly increased the potential rate of protein synthesis in liver after 3 days. Plasma amino acids were comparable with controls whereas in the unfed-group concentrations suggested utilization of alanine and breakdown of muscle. Three days of IVN also increased plasma fibronectin and IgA but increases of prealbumin, IgM, and complement C3 were only significant in the group fed for 7 days. On the 7th postoperative day plasma proteins were decreased similarly in each group. This study shows that concentrations of several plasma proteins, in preoperative patients reflect net rates of hepatic protein synthesis and are susceptible to depletion during starvation and repletion by 3 or 7 days of IVN.

Aged↗
PubMed1990

[Problems in standardization of the immunochemical detection of plasma proteins. I. International reference standards for plasma proteins. II. Immunochemical relation of measurement signals and values].

When the results of plasmaprotein determination--dependent on the reagents, methods and other factors--are expressed in international units (IU) a better comparison of the results between different labs is possible. By this means and using the corresponding reference values and reference intervals the reliability of the interpretation of laboratory data will increase. The situation regarding the WHO IRP's for plasma proteins (approx. 20 parameters) and the relation from IU to mg in the reagents of the Behringwerke AG are reported. The overlability of WHO IRP's has not allowed yet to achieve an optimal standardization of the immunochemical methods for measurement of plasma proteins. This depends especially on the complexity of the antigen-antibody reaction. The relationship between the measured signal and the hence obtained value will be discussed in details in the second part of this paper. Hereby especially the reciprocal interdependence between physicochemical properties of proteins and the deriving immunochemical behaviour as well as the dependence of the results from the quality of the antibodies-containing reagents are also considered. Possible solutions for a better control system of the plasma protein determination by using the so called master calibrators as internal support for validation will be presented. Furthermore, general immunochemical postulates and rules for optimization of the standardization of plasma protein determination will be proposed and discussed.

Antigen-Antibody Complex↗
PubMed1979

Drug-protein interaction: plasma protein binding of furocoumarins.

The binding of six furocoumarins (angelicin, psoralen, 8-methoxypsoralen, 5-methoxypsoralen, 8-methylpsoralen, 4,5'8-trimethylpsoralen) to human serum and human serum albumin was studied by equilibrium dialysis using tritium labelled compounds. The results indicated that in serum all furocoumarins are bound mostly by albumin, the extent of binding being related to the structure of the furocoumarins; at any rate, high values of the bound drug, ranging from 84 to 97% were observed. The percentage of binding is strictly related to the water solubility of the compounds. A limited number of binding sites, n = 1-2.4, were detected in the albumin molecule, indicating a high specificity in the binding process. The association constants of the furocoumarins to albumin. Ka, ranged from 1.2 X 10(4) M-1 (8-methoxypsoralen) to 1.9 X 10(5) M-1 (4,5'8-trimethylpsoralen).

Biological Availability↗
PubMed1976

Plasma protein profiling: the diagnostic evaluation of disorders in plasma protein composition by a new immunoelectrophoretic method.

A new electroimmunoprecipitation technique is presented by means of which a great variety of antigens e.g. plasma proteins can be simultaneously and quantitatively determined with a single-step electrophoretic separation. The essential features of the new technique are: (a) subdivision of the antibody gel into gel strips containing monospecific antibodies to individual plasma proteins. (b) sample application as a "sample gel" filling a trough over the width of the immunoplate. Quantitation is based on the fact that the distance an antigen can migrate within a gel containing a defined amount of specific antibody directed against the antigen is determined by the concentration of the appropriate antigen within the sample. The area where the antigen is finally completely consumed by immunoprecipitation and antibody present in excess is sharply delineated. The applicability of the method in simultaneous quantitative determination of 15 plasma proteins is demonstrated with plasma from healthy blood donors and patients with various diseases. The advantage of the new technique as compared to commonly used clinical acetate folia electrophoresis is the high degree of specificity for the determination of a great number of individual, diagnostically meaningful plasma proteins. The advantage over common quantitative two-dimensional immunoelectrophoresis is its uncomplicated way of evaluation. The potential clinical application of the new quantitative immunoelectrophoretic technique in diagnostic screening and differential diagnosis is discussed.

Blood Proteins↗
PubMed1975

Effect of ionic strength and ionic composition of assay buffers on the interaction of thyroxine with plasma proteins.

When plasma proteins are diluted with buffer the ionic strength and ionic composition of that buffer affects the interactions between thyroxine (T4) and its plasma protein-binding sites. Increases in phosphate, chloride or barbiturate ion concentration from 50 to 200 mmol/l caused a significant decrease in the affinity of plasma proteins for T4, and a concurrent increase in the concentration of unbound T4. These results cannot be completely accounted for by changes in ionic strength since at the same ionic strength different anions caused quantitatively different effects on unbound T4 concentration. The degree of depression of T4 binding by the three anions studied was in the order barbiturate greater than chloride greater than phosphate. The results of a systematic study on the composition of diluent buffer systems indicated that when a 50 mM-sodium phosphate-100 mM-NaCl buffer (pH 7-4) was used as a plasma diluent, there were unlikely to be gross changes in the T4-binding properties of plasma proteins with dilution.

Barbiturates↗