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PubMed1982

Glycosylation of plasma proteins with [U-14C]glucose in vivo.

Within 1-12 h after subcutaneous injection of [U-14C]glucose, significant amounts of 14C attached by stable (probably covalent) bonds were found in plasma proteins of rats. More than 30% of 14C of [U-14C]glucose injected per 1 g body weight was incorporated into proteins contained in 1 mL of plasma. Less than 5% of 14C of the [14C]glucose-labelled plasma proteins was soluble in cold dilute perchloric acid, whereas more than 80% of 14C in the [14C]glucose-labelled plasma proteins was soluble in 50% saturated solutions of ammonium sulfate. From [U-14C]glucose-labelled plasma proteins, approximately 50% of the incorporated 14C was recovered in carbohydrate moieties (sialic acid, 8-12%; mannose and galactose, 15-31%; hexosamines, 8-14%) and the rest of the 14C (42-64%) was recovered from protein residue. Gel-filtration and electrophoresis profiles of distribution of 14C in [U-14C]leucine-labelled plasma proteins were very similar to those of [U-14C]glucose-labelled plasma proteins; a relatively high specific radioactivity was observed in fractions having an apparent molecular weight of 105 X 10(3) or its multiples (220 X 10(3) and 520 X 10(3)). However, about 99% of the incorporated 14C was recovered from the protein residue of [14C]leucine-labelled plasma proteins, whereas only traces of 14C were found in the carbohydrate moieties. [U-14C]Alanine is also a relatively poor precursor of 14C for incorporation into carbohydrate moieties of plasma proteins as compared with [U-14C]glucose.

Animals↗
PubMed1987

Intracellular precursor forms of plasma proteins: their functions and possible occurrence in plasma.

An attempt is made to review the steps in the biosynthesis of plasma proteins by the liver and to point out intermediate precursor forms that might escape to the plasma. With the use of immunochemical techniques such as immunofixation electrophoresis it is possible to identify these precursors when they present an unusual bands on protein electrophoresis. The discovery of the role of vitamin K in the formation of the blood-clotting proteins, for example, followed the immunochemical detection of an abnormal form of inactive prothrombin in plasma. The chief types of precursors likely to occur in blood are forms that are incompletely glycosylated, phosphorylated, or sulfated, or which are single peptide chains of multichain proteins. Precursors containing basic propeptides such as proinsulin or proalbumin may also appear. By being alert to the possible appearance of intracellular forms in plasma, the clinical chemist may be able to relate their presence to the nature of the disease process responsible.

Animals↗
PubMed1985

[Erythrocyte-associated plasma proteins, a further aspect of erythrocyte function?].

The amount of plasma proteins associated to erythrocytes was determined or calculated by using three different techniques. Thus, there are 3.48 X 10(12) g of protein in a single erythrocyte or 94.12 g of protein respectively in the total of all erythrocytes in a healthy man with a body weight of 70 kg. The mass of plasma protein associated to erythrocytes will decrease in case of immunocomplex aggregates or otherwise denatured plasma proteins being fixed to the erythrocyte surface so that from a purely calculating point of view protein amounts on a scale of up to 46% of all plasma proteins may enter the free blood plasma under extreme conditions. In this, an immediately efficient possibility of compensation is seen by the authors in case of an acute consumption of blood proteins.

Antigen-Antibody Complex↗
PubMed1986

Contribution of plasma proteins to the vitreous of the rat.

The extent of plasma proteins in the vitreous humor of the rat was determined. Disc gel electrophoresis of the soluble proteins of the rat vitreous humor showed many protein bands, but most of the bands did not coincide with those of rat plasma. Using antibodies to rat plasma proteins, immunological analyses of vitreous and plasma, including fractions separated by high-pressure gel permeation chromatography, showed that several vitreous proteins react with plasma protein antibodies. However, only albumin and transferrin were found to be completely identical in both fluids. The concentration of albumin in vitreous was about 625 micrograms/ml and that of transferrin was 61.6 +/- 19.1 (S.D.) microgram/ml. The total protein concentration in vitreous was 9.5 +/- 0.5 (S.D.) mg/ml. The ratio of transferrin to albumin in the vitreous was approximate to that of plasma, but the sum of the two proteins accounted for less than 10% of the total protein. These data indicate that in the rat some plasma proteins, particularly albumin and transferrin, are found in the vitreous, but most of the soluble proteins appear to originate from sources other than plasma, such as the vitreous itself or in surrounding tissues including the ciliary body and the retina.

Animals↗
PubMed1972

Studies on diarrhea in neonatal calves: the plasma proteins of normal and diarrheic calves during the first ten days of age.

The concentration of serum proteins and plasma fibrinogen were determined in 151 normal and 49 diarrheic calves at intervals from birth to ten days of age. There were significant differences in the concentrations of the various serum proteins in normal calves when the results were analysed at six age intervals. There was no significant relationship between the concentration of the various proteins and the season of the year. Of the diarrheic calves, those that died had significantly lower gamma globulin concentrations than the other calves. Severely diarrheic and dehydrated calves had significantly increased serum albumin and alpha glabulin concentrations and decreased gamma globulin concentrations. No significant variation occurred in total serum protein concentration. Plasma fibrinogen concentrations were similar in normal and diarrheic calves.

Alpha-Globulins↗
PubMed1999

Production and characterization of monoclonal antibodies against pregnancy-associated plasma protein A.

Pregnancy-associated plasma protein A (PAPP-A) was found to be a good first trimester maternal serum marker, together with free beta-human chorionic gonadotrophin (HCG) subunits, for the biochemical screening of fetal trisomy 21 (Down's syndrome). We have raised monoclonal antibodies (mAbs) against PAPP-A purified from human pregnancy serum. The different antibodies were characterized biochemically by Western blot analysis and in terms of specificity (reaction with non-pregnant and male serum). Their performance in Down's syndrome screening was assessed in comparison with an existing enzyme-linked immunosorbent assay method after labelling of the different mAbs with biotin or horseradish peroxidase. A pair of mAbs was eventually chosen for a double-antibody sandwich protocol. The selected combination was found to have a significantly increased specificity (P = 0.0116) over the method using (purified) polyclonal antibodies, together with slightly increased sensitivity. In our limited number of Down's syndrome pregnancy samples (n = 17) and controls (n = 18), the medians as well as the multiples of the median values (for the affected cases) were comparable between the two methods described.

Antibodies, Monoclonal↗
PubMed1975

The rôle of plasma proteins in chronic expansion of plasma volume in tropical splenomegaly syndrome. III. The interrelationships of albumin, immunoglobulins and plasma volume.

The effect of alterations in serum protein levels on plasma volume in tropical splenomegaly syndrome has been investigated by determining plasma volume, serum albumin, globulin and immunoglobulin levels in 64 adult New Guineans suffering from this disease. Plasma volumes ranged from 51-2 to 129 ml./kg. Significant positive correlations were found between plasma volume and intravascular pools of albumin, IgG and IgM. Multiple regression analysis demonstrated that 70% of the variance in plasma volume in this series was attributable to increases in these three pools, IgM and IgG accounting for 42% of the total and albumin for 28%. It is probable that the unexplained 30% of plasma volume expansion arises through a splenic arterio-venous shunt effect. It is suggested that initially in tropical splenomegaly syndrome the splenic shunt and immunoglobulin overproduction combine to produce expansion of plasma volume and a fall in intravascular colloid osmotic pressure; that the latter provides the stimulus to increased albumin synthesis, and that this further aggravates the plasma volume expansion and the consequent dilutional anaemia commonly seen in this disease.

Blood Proteins↗
PubMed2004

The approach to conception for women with seminal plasma protein hypersensitivity.

PROBLEM: Allergic reactions to human seminal plasma protein has become increasingly recognized in the medical community. Treatment for most allergic conditions usually begins with avoidance of the offending allergen. For women with seminal plasma protein hypersensitivity (SPH) who desire to conceive, this approach is unacceptable. We describe a case report of a woman with an SPH who desired to have unprotected intercourse in order to conceive. METHODS: The patient underwent skin prick testing to her fiancé's fresh undiluted semen. Serum-specific IgG and IgE was performed by ELISA to the fiancé's whole seminal plasma and seminal plasma proteins (SPP). The patient underwent an intravaginal graded challenge to whole seminal fluid. Intrauterine insemination with washed spermatozoa was attempted but in vitro fertilization was subsequently required. RESULTS: The patient had a positive prick test to whole seminal plasma but negative specific IgG and IgE ELISA to SPPs. An intravaginal graded challenge to whole seminal plasma was well tolerated. However, she experienced a subsequent severe local reaction after unprotected intercourse. She deferred treatment with systemic desensitization to relevant SPPs. She failed intrauterine insemination but successfully conceived with in vitro fertilization. CONCLUSION: This case report emphasizes that SPH is not associated with sterility. It also indicates that whole seminal plasma graded challenge is not uniformly successful for the treatment of SPH.

Adult↗
PubMed1985

The clinical significance of alpha 1-antitrypsin-elastase (alpha 1AT-ELP) and alpha 2-antiplasmin-plasmin (alpha 2AP-PL) complexes for the differentiation of coagulation protein turnover: indications for plasma protein substitution in patients with septicaemia.

In inflammation, particularly in septicaemia, complex coagulation disorders may lead to a dangerous haemorrhagic diathesis. The conventional concept for this syndrome called DIC implicates the occurrence of active thrombin in the circulation, which may be followed by hyperfibrinolysis due to plasmin formation. In this study data are presented suggesting an important role for a third proteolytic system, granulocytic elastase. The complexes of plasmin and elastase with their specific inhibitors, alpha 2-antiplasmin-plasmin (alpha 2AP-PI) and alpha 1-antitrypsin-elastase (alpha 1AT-ELP) were determined immunologically. The alpha 1AT-ELP appears mainly in gram-negative septicaemia, particularly in meningococcal disease. The estimation of alpha 2AP-PI and alpha 1AT-ELP, together with a method for the detection of the antithrombin III--thrombin complex which remains to be established, is a suitable tool for for the differential diagnosis of the consumption of coagulation proteins. The assumption that at least three proteolytic systems participate in the development of the haemorrhagic diathesis during inflammation leads to the concept of a broad, comprehensive substitution therapy with e.g. concentrates of AT III, PPSB, or fresh frozen plasma. The aim of this treatment is to replace not only the consumed procoagulatory factors, but also the lacking inhibitors in order to control this "abnormal proteolysis syndrome".

Adult↗
PubMed1995

Characterization and quantification of plasma proteins excreted in faeces from healthy humans.

Faecal plasma protein loss was studied in 38 healthy adults. Using crossed immunoelectrophoresis and single radial immunodiffusion the most frequently found proteins were alpha 1-antitrypsin, IgA, alpha 1-antichymotrypsin (found in 97, 92, and 84% of subjects), prealbumin and IgM (both found in 55%). The major plasma proteins, albumin and IgG, were found in 37 and 13% of subjects, respectively, and in trace amounts only. alpha 2-macroglobulin could not be detected. There was no relation between the presence of proteins in faeces and their plasma concentration. When added to faeces, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and prealbumin were resistant to incubation (37 degrees C, 48 h), whereas albumin, IgG, IgM, and IgA were rapidly degraded (within 8-24 h). Some IgA was bound to secretory component, indicating enteric secretion. alpha 2-macroglobulin was semi-resistant to degradation, but its passage to the intestinal lumen may have been prevented by its molecular size. In conclusion, resistance to degradation, enteric secretion, and low molecular weight are the primary factors which favour the excretion of plasma proteins in faeces. The technique used in this study allows further studies in patients with inflammatory changes and protein-losing enteropathy.

Adult↗
PubMed1991

Interaction of plasma proteins with heparinized gel particles studied by high-resolution two-dimensional gel electrophoresis.

In order to further the understanding of protein-surface interactions in the coagulation system, we have chosen to study plasma protein adsorption onto heparin-immobilized surfaces. Heparin-binding proteins are abundant in plasma: a search of amino acid sequences revealed that many plasma proteins have possible heparin binding sites. Plasma protein adsorption to the heparinized surfaces is monitored by a novel technique in which the solution depletion of proteins is analytically determined using quantitative two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). This method enables simultaneous, quantitative detection of the majority of plasma proteins before, during, and after their adsorption onto high surface area adsorbents. Using computerized densitometry of silver-stained 2-D PAGE gels, the amount of each protein can be determined from the integrated optical density of each protein "spot." Kinetics of adsorption and adsorption isotherms of four important heparin binding proteins, antithrombin III (ATIII), complement factor C3 (C3), apolipoprotein AI (Apo-AI) and apolipoprotein AIV (Apo-AIV) are reported in this paper. From the adsorption isotherms, the apparent binding constants of each protein-immobilized heparin complex, Ka, were calculated. The surface binding constants were of the same order of magnitude as the respective solution binding constants in the literature. The surface binding constants followed the same order as the respective solution binding constants: Ka (ATIII) greater than Ka (Apo-AIV) greater than Ka (C3) greater than Ka (Apo-AI), indicating that protein binding to the immobilized heparin used is not essentially different from solution binding.

Adsorption↗
PubMed1998

von Willebrand factor, fibrinogen and other plasma proteins as determinants of plasma viscosity.

Plasma viscosity and fibrinogen are risk factors for cardiovascular disease and on rheological grounds, it is widely believed that the latter is a major determinant of the former. However, other plasma constituents may also be important determinants of plasma viscosity. Our aim was to determine whether or not levels of von Willebrand factor contributed to plasma viscosity. We measured plasma viscosity, fibrinogen, von Willebrand factor, immunoglobulins G, A and M, total, HDL- and LDL-cholesterol, triglycerides and albumin in 95 patients with peripheral arterial disease and in 120 healthy controls. A stepwise multivariate analysis was performed to determine the major influences of plasma viscosity. We also measured fibrinogen, von Willebrand factor, immunoglobulins G, A and M, total, HDL- and LDL-cholesterol, triglycerides, albumin and viscosity in 32 smokers as they successfully progressed to being non-smokers. The level of von Willebrand factor was an independent influence on plasma viscosity in the controls (P < 0.05), patients (P < 0.01) and in the combined group (P < 0.001). von Willebrand factor, fibrinogen and plasma viscosity, but not the immunoglobulins, lipoproteins or albumin, fell (P < 0.05) in smokers as they became non-smokers. We find that von Willebrand factor contributes to plasma viscosity, hence a reduction in levels of von Willebrand factor should result in a reduction in viscosity. These data may have implications for the pathogenesis of cardiovascular disease.

Adult↗
PubMed1981

Isolation of peptides from uremic plasma that inhibit phenytoin binding to normal plasma proteins.

The binding of many drugs to plasma proteins is altered in renal disease. Explanations include hypoproteinemia, alterations in the native structure of the binding protein, and competitive or noncompetitive inhibition. The binding of phenytoin to proteins was studied in plasma from patients with chronic renal failure by equilibrium dialysis at 37 degrees. Charcoal adsorption was used to normalize the binding. Substances that appeared to be peptides were isolated; they inhibited the binding of phenytoin to normal plasma proteins. The data suggest that the defect in phenytoin-protein binding in chronic renal failure may be due to competitive or noncompetitive inhibition by peptides.

Adsorption↗
PubMed2005

Plasma protein and blood volume restitution after hemorrhage in conscious pregnant and ovarian steroid-replaced rats.

We have previously shown that both plasma protein restitution and plasma volume restitution are significantly enhanced in female rats hemorrhaged during the proestrus phase of the estrous cycle. Estradiol and progesterone levels are markedly elevated during proestrus and also increase during pregnancy. The present studies were therefore designed to determine whether the ability to restore plasma protein and blood volume after hemorrhage is augmented during pregnancy and by chronically elevated estradiol levels. The response to moderate hemorrhage (22-23% blood loss) was evaluated in conscious pregnant rats during early and midgestation and compared with that of virgin female rats studied during metestrus. At 22 h posthemorrhage, plasma volume had increased to greater than basal levels, and blood volume was restored to 93 +/- 1% (metestrus), 91 +/- 2% (early pregnancy), and 98 +/- 2% (midgestation) of control (P > 0.05). Animals hemorrhaged during metestrus or early pregnancy restored the same amount of protein to the plasma as had been removed, whereas those hemorrhaged during midgestation restored nearly 50% more plasma protein than had been removed (P < 0.01). In ovariectomized animals with chronic steroid replacement that maintained plasma progesterone at metestrus levels (15 +/- 2 ng/ml) but raised plasma estradiol to twofold that of midgestation (22 +/- 3 pg/ml), the blood volume and plasma protein restitution responses to hemorrhage did not differ from those of ovariectomized animals with no steroid replacement. In summary, posthemorrhage restoration of plasma protein content is significantly augmented during midgestation, but not during early pregnancy. This augmented response cannot be attributed to chronic elevation of plasma estradiol levels alone.

Animals↗
PubMed1986

Measurement of glycosylated haemoglobins and glycosylated plasma proteins in animal models with diabetes or inappropriate hypoglycaemia.

Stable glycosylated haemoglobins and glycosylated plasma proteins were determined by affinity chromatography using Glycogel B in animal models with diabetes or inappropriate hypoglycaemia. Adult Aston ob/ob mice and C57BL/KsJ db/db mice exhibited 1.5-1.9 fold increases of body weight, 2.5-3.4 fold elevations of plasma glucose and 20.9-29.3 fold elevations of plasma insulin. Glycosylated haemoglobins and glycosylated plasma proteins were raised 7.2-8.2 fold and 6.6-6.7 fold respectively. In adult NEDH rats, administration of streptozotocin or implantation of transplantable insulinoma fragments produced reciprocal changes in insulin and glucose concentrations either resulting in the onset of insulin deficiency (5.9 fold decrease) and hyperglycaemia (3.2 fold increase) by 2 days, or hyperinsulinaemia (2.1 fold increase) and hypoglycaemia (1.4 fold decrease) by 6 and 8 days, respectively. Glycosylated plasma proteins were increased (1.2 fold) rapidly after streptozotocin treatment followed by glycosylated haemoglobins (1.6 fold increase) after 8 days. In contrast, the decreases in glycosylated plasma proteins and glycosylated haemoglobins (4.4 fold and 1.4 fold, respectively) in insulinoma-bearing rats preceded the demonstration of hypoglycaemia by 5 and 2 days, respectively. Glycosylated plasma proteins in insulinoma-bearing rats returned to pretransplantation values at 10-16 days. Good correlations were observed in mice and rats between glucose and both glycosylated haemoglobins (r = 0.92 and r = 0.90, respectively) and glycosylated plasma proteins (r = 0.85 and r = 0.93), and between the glycosylated blood proteins themselves (r = 0.95 and r = 0.91). The results show that the measurement of glycosylated blood proteins by affinity chromatography using Glycogel B provides a sensitive and reliable indicator of the recent glycaemic environment.

Animals↗
PubMedDate not supplied

The effect of age on the plasma protein binding of pentobarbitone in the mouse. A brief note.

Old mice show an increased sensitivity to parenteral pentobarbitone compared with young adult mice, despite similar plasma concentrations of the drug. One factor may be an alteration in the binding of barbiturate to the plasma protein, perhaps consequent on reduced hepatic synthesis of plasma protein with advancing age. As part of a study of the effect of age upon the pharmacological and adaptive response to barbiturates, binding of pentobarbitone to plasma proteins from mice of different ages was measured by equilibrium dialysis in the presence of a standard concentration of the drug. The total plasma protein concentration was measured and found to be the same in both age groups. The plasma protein binding of pentobarbitone was found to correlate significantly with the plasma albumin concentration, which was lower in the older mice. However, there was no significant overall difference in pentobarbitone binding between old and young mice. Pretreatment of the mice with phenobarbitone for 21 days had no effect upon the capacity for plasma protein binding of pentobarbitone in either age group. Thus, it seems unlikely that the increased sensitivity of older mice to pentobarbitone can be explained in terms of altered plasma protein binding of the drug.

Aging↗