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PubMed1998

Human cholesteryl ester transfer protein measured by enzyme-linked immunosorbent assay with two monoclonal antibodies against rabbit cholesteryl ester transfer protein: plasma cholesteryl ester transfer protein and lipoproteins among Japanese hypercholesterolemic patients.

Plasma cholesteryl ester transfer protein (CETP) concentrations were measured in Japanese subjects by an ELISA with two different monoclonal antibodies that were raised against rabbit CETP and cross-reacted against human CETP. Among 63 patients who consecutively underwent coronary angiography, the plasma CETP of 37 patients with luminal stenosis > or = 50% in their coronary arteries was not significantly different from that of the 26 patients with luminal stenosis < 50%. No other lipoprotein-related measurement except HDL-cholesterol differentiated the two groups. Among 40 hypercholesterolemic patients, no lipoprotein-related measurement other than LDL-cholesterol was found to positive correlate with the CETP. Before and after the treatment of 23 patients with simvastatin 5 mg a day for 4 weeks, plasma CETP markedly decreased in those whose pretreatment CETP was > or = 3 mg/L; no change was observed for those with lower pretreatment CETP. In the former group, negative correlation between CETP and HDL-cholesterol was demonstrated only in the posttreatment plasma.

Adult↗
PubMedDate not supplied

A comparative study of the glycosylated plasma proteins in diabetic Nigerians.

The levels of glycosylated plasma proteins and haemoglobin in some Nigerian diabetic patients in Lagos metropolis have been investigated by the thiobarbaturic acid (TBA) assay technique. The mean values of the glycosylated plasma proteins: 40.8 +/- 5.89 umol/L fructose equivalent and glycosylated haemoglobin, 105.0 +/- 20.81 umol/L fructose equivalent were approximately twice that found in the controls, 23.5 +/- 3.00 and 64.7 +/- 5.87 umol/L fructose equivalent respectively. The glycosylated haemoglobin values were considerably higher in both diabetics and control than the corresponding glycosylated plasma proteins. Glycosylated plasma proteins had a high positive correlation with both plasma glucose level and glycosylated haemoglobin. These findings suggest that determination of glycosylated plasma proteins (GPP) could be employed to assess diabetic control given the shorter half-life of the plasma proteins. The GPP values are probably good indicators of integrated short-term glycaemia.

Blood Glucose↗
PubMed1989

Purification and characterization of plasma protein C inhibitor.

Plasma protein C inhibitor (PCI) was purified to homogeneity (greater than 95%) with good recovery (greater than 25%) and reproducibility, and the inhibition of a number of blood clotting and fibrinolytic enzymes by purified PCI was studied. PCI inhibited activated protein C (APC), two-chain urokinase (2c-uPA), two-chain tissue plasminogen activator (2c-tPA), thrombin, factor Xa, plasma kallikrein and factor XIa, and this inhibition was accelerated by heparin. The inhibition of each enzyme was accompanied by formation of enzyme inhibitor complexes and by degradation of the inhibitor to lower molecular weight derivatives. Plasma kallikrein and factor XIa cleaved PCI of native Mr = 57,000 into two products with Mr = 54,000 and 52,000 whereas the other enzymes converted the PCI to a product with Mr = 54,000. PCI did not detectably inhibit alpha-factor XIIa or plasmin. Kinetic studies using PCI yielded the following second-order rate constants for inhibition of human APC, 2c-uPA, 2c-tPA, thrombin, factor Xa, kallikrein and factor XIa respectively: 0.65 x 10(4), 0.22 x 10(4), 0.08 x 10(4), 0.61 x 10(4), 2.01 x 10(4), 6.50 x 10(4), and 9.03 x 10(4) M-1s-1 in the absence of heparin and 1.58 x 10(6), 0.43 x 10(6), 0.03 x 10(6), 0.52 x 10(6), 0.09 x 10(6), 0.18 x 10(6) and 0.74 x 10(6) M-1s-1 in the presence of optimal concentrations of heparin. The rate constants for the inhibition of factor XIa and 2c-uPA by PCI suggest a possible role of PCI in the physiologic regulation of these enzymes. The second order rate constants for inhibition of bovine APC and Gla-domainless bovine APC by human PCI were 0.61 x 10(4) and 0.26 x 10(4) M-1s-1 in the absence of heparin and 0.54 x 10(6) and 0.71 x 10(6) M-1s-1 in the presence of heparin, respectively. Calcium ions (0.05 to 4 mM) did not affect these rate constants. The results obtained with normal and Gla-domainless APC indicate that the Gla domain of APC is not required for inactivation by PGI and is not essential for the heparin stimulation of this reaction.

Blood Coagulation Factors↗
PubMed1982

Effects of total plasma concentration and age on tolbutamide plasma protein binding.

Tolbutamide plasma protein binding at different total tolbutamide concentrations was determined in 44 healthy, nonsmoking, drug-free men from 23 to 87 yr old. The data showed that unbound drug increased with total tolbutamide plasma concentration and with age, but that neither the binding equilibrium constant nor the number of binding sites correlated with age. The increase in unbound fraction with age could be partially explained by the decrease in albumin concentration in elderly subjects. Results of multiple linear regression analysis indicated that, although age had a considerably greater influence than albumin concentration, total tolbutamide concentration was the most important determinant of the unbound fraction. Thus, both age and total plasma concentration may affect tolbutamide kinetics.

Adult↗
PubMedDate not supplied

Hemostatic balance during the acute inflammatory reaction. (II). With special reference to plasma protein C.

While plasma fibrinogen level and clotting factor VIII activity obviously increased during the acute inflammatory reaction caused by intramuscular injections of turpentine in 10 rabbits, the activity of plasma protein C, with anticoagulant and antithrombotic effects, was found to display a slight yet significant (p < 0.02) decrease. When compared to protein C activity in humans, this vitamin K-dependent serine protease was found to be lower in rabbits (52, 7% +/- 3,63 of standard human plasma) and this activity decreased to 45,8% +/- 2,80 (mean +/- SEM), 48 hours after the injection of turpentine. This slight decrease should however be interpreted in the context of other disturbances of the hemostatic balance caused by inflammation and may contribute to the intravascular deposition of fibrin.

Acute-Phase Reaction↗
PubMed1991

Plasma protein catabolism in ethanol- and colchicine-treated liver slices.

The present study was conducted to determine whether the antisecretory agents colchicine and ethanol affect the intracellular degradation of plasma proteins in rat liver. Plasma proteins were prelabeled in vivo with [3H]leucine and their levels were monitored immunochemically in both the medium and extracts of rat liver slices incubated alone or in the presence of 50 microM colchicine or 25 mM ethanol. Compared with those left untreated, colchicine-treated slices had a 40-55% lower secretory capacity and, at one point, showed significant hepatocellular retention of total plasma proteins. Plasma protein secretion by ethanol-treated liver slices was 22-32% lower than controls, but there was no detectable retention of unsecreted plasma proteins in the ethanol-treated liver tissue. In all experiments, the total radioactivity in plasma proteins (i.e., the immunoprecipitable radioactivity in the liver plus that in the medium) decreased with time in a manner suggestive of intracellular degradation. Regression analyses of the rates of degradation of presecretory proteins revealed that compared with controls, plasma protein catabolism was accelerated 57% in colchicine-treated slices. In ethanol-treated liver slices, there was a 50% increase in the degradation of total plasma proteins and a 46% increase in albumin catabolism. In all cases, degradation was intracellular. These findings indicate that inhibition of hepatic protein secretion by either colchicine or ethanol is associated with accelerated catabolism of unsecreted plasma proteins, suggesting that hepatocellular degradative processes are responsive to changes in the levels of presecretory proteins and/or perturbations of the secretory process.

Animals↗
PubMed2001

Nitrated and oxidized plasma proteins in smokers and lung cancer patients.

Cigarette smoking is a cause of lung cancer and other respiratory diseases. Oxidants either present in cigarette smoke and/or formed in the lung of smokers may trigger oxidative and nitrative damage to DNA and cellular components, contributing to carcinogenesis. We have used immunodot and Western blot analyses to measure nitrated (nitrotyrosine-containing) and oxidized (carbonyl-containing) proteins in plasma samples collected from 52 lung cancer patients and 43 control subjects (heavy and light smokers, nonsmokers with or without exposure to environmental tobacco smoke). The levels of nitrated proteins were significantly higher in lung cancer patients than in controls (P = 0.003). On the other hand, the levels of oxidized proteins were significantly higher in smokers than in nonsmokers (P < 0.001). Western-blot analyses showed the presence of two to five nitrated proteins and one oxidized protein. Using immunoprecipitation and Western-blot analyses with eight different antibodies against human plasma proteins, we identified fibrinogen, transferrin, plasminogen, and ceruloplasmin as nitrated proteins and fibrinogen as the only oxidized protein present in human plasma of lung cancer patients and smokers. Our results indicate that cigarette smoking increases oxidative stress and that during lung cancer development, formation of reactive nitrogen species results in nitration and oxidation of plasma proteins.

Aged↗
PubMed2000

Deamidation as a widespread phenomenon in two-dimensional polyacrylamide gel electrophoresis of human blood plasma proteins.

The human plasma protein patterns obtained by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is a good model system for post-translational modifications because of the existence of several "ladders" of protein spots [Anderson, N. L., Anderson, N. G., Electrophoresis 1991, 12, 883-906], so-called "trains" of spots. Our investigation of several proteins, amongst others beta2-microglobulin and the haptoglobin chains, found the differences in isoelectric points (p/) to be due to deamidation of asparagines. After enzymatic cleavage with endopeptidases in the 2-D polyacrylamide gel, the asparagine and deamidated asparagine containing peptides were separated and quantified by reversed-phase HPLC. In order to separate these peptides, a neutral pH system was established and, as a result, the differences in hydrophobicity of asparagine-containing and deamidated asparagine-containing peptides increased. But how do deamidated asparagines contribute to the observed spot pattern? One spot in the 2-D gel consists of a mixture of protein species with the same number of deamidated asparagines but on different sequence position sites. The difference between the spots in the "ladder" is a growing number of negative charges introduced in the protein by an increasing number of deamidated asparagines. As a consequence, the mass difference between two spots is exactly 1 Da, which is shown in this paper for intact protein masses and the corresponding deamidated peptides.

Amides↗
PubMed2003

Proteinase inhibitors in aggregated forms of boar seminal plasma proteins.

Boar seminal plasma proteins were separated by gel chromatography on Sephadex G-75 into five fractions (I-V). Serine proteinase inhibitors were found mainly in the protein fraction with relative molecular weight 5-25kDa. Small amounts of these inhibitors were also found in the high molecular weight protein fraction (M(r)>100kDa). The protein fraction containing most of the proteinase inhibitory activity was further separated by RP HPLC. Isolated proteins were characterized by SDS electrophoresis and immunoblotting, N-terminal amino acid sequencing and by determination of the proteinase inhibitory activity. In the fraction containing proteinase inhibitors, also beta-microseminoprotein (beta-MSP), AQN 1 and lactoferrin were identified. The possible existence of complexes of protein components in the fraction with relative molecular weight 5-25kDa was studied in detail using gel chromatographic separation on Sephadex G-50. A part of proteinase inhibitors with M(r) 8kDa was eluted together with AQN 1 spermadhesin. An interaction of isolated spermadhesin AQN 1 and proteinase inhibitor was shown.

Amino Acid Sequence↗
PubMed1981

Fractionation of plasma proteins with PEG.

Plasma proteins were fractionated with polyethylene glycol (PEG-4000) and the effects of pH, ionic strength and temperature were examined. Fractionation with 15% PEG was the most suitable for obtaining a precipitate containing mainly IgG, and a supernatant containing chiefly albumin. These fractions may then be purified further.

Blood Proteins↗
PubMed1978

Assessment of protein-calorie malnutrition in surgical patients from plasma proteins and anthropometric measurements.

Six plasma proteins, two anthropometric measurements, hemoglobin and total lymphocytes were determined in 54 surgical patients and 19 normal individuals. Preoperative patients had a low mean values for prealbumin, retinol binding protein, and arm muscle circumference. In postoperative patients, plasma transferrin, albumin, hemoglobin, total lymphocytes and body weight were also low and complement C3 was higher than normal. A correlation matrix for 10 variables showed interrelationships between the biochemical and anthropometric data. Prealbumin and transferrin were highly correlated with most of the variables. The effects of protein-calorie malnutrition were analyzed from the data ranked and grouped according to the plasma prealbumin or transferrin concentration. Those groups with low mean values for these proteins also had low values for most of the other variables. Protein calorie malnutrition in surgical patients may be conveniently assessed from plasma prealbumin, transferrin, arm muscle circumference, percentage weight loss, and hemoglobin.

Adult↗
PubMed2006

Affinity liquid chromatography and capillary electrophoresis of seminal plasma proteins.

Interactions of boar, bull, and human seminal plasma proteins with heparin and phosphorylcholine were studied by affinity LC using heparin immobilized to a Toyopearl support. A step gradient elution from 0.15 to 1.50 M NaCl was employed to elute the seminal plasma proteins. Relative amounts of the heparin-binding fraction of seminal plasma proteins (H+) in seminal plasma of three species were determined. Further on, the fraction of seminal plasma proteins interacting with phosphorylcholine-binding proteins (P+) was evaluated. P+ proteins were not found in human seminal plasma and their highest amount was present in bull seminal plasma. A CE method was developed for separation of seminal plasma proteins. Various capillaries and separation conditions were tested; the best resolution was obtained in a bare-silica capillary, with a micellar system consisting of a 0.02 M borate buffer and 0.05 M SDS pH 10.0. The optimized conditions were applied to the identification of the components in boar plasma.

Animals↗
PubMed1975

Plasma protein binding of carbamazepine.

The binding of carbamazepine to the proteins of human plasma has been studied using ultrafiltration techniques. In vitro studies at 37 degrees C showed the relation between concentration of unbound drug and total drug to be linear through the range of total concentration of 5 to 50 mug/ml. The per cent unbound drug increased slightly as concentration increased. There was little difference between the extent of binding at 4 degrees C and 20 degrees C, but more carbamazepine was unbound at 37 degrees C. Under in vitro conditions, 6 other anticonvulsants, and aspirin, were tested individually, each at high therapeutic or toxic concentration, and shown not to displace carbamazepine from plasma proteins to a significant degree. The extent of binding of carbamazepine in vivo was determined in a total of 54 plasma samples collected from treated patients; 26.9 plus or minus SD 9.4 percent of the drug was unbound. In blood samples from 23 of these patients, the red cell concentration of carbamazepine averaged 38.3 plus or minus SD 17.9 percent of the plasma concentration. The effects of hepatic and renal diseases on the carbamazepine binding capacity of plasma proteins were assessed by comparing the binding capacity of plasma from disease persons with that from normal subjects. There was no significant difference in binding capacity between plasma from patients with renal disease and that from normal subjects. However, the plasma from patients with hepatic disease bound a slightly lower percentage of carbamazepine than did normal plasma (p smaller than 0.05). This alteration did not correlate with changes in any of 15 biochemical parameters measured in these patients. The clinical significance of these results is discussed.

Adolescent↗
PubMed1991

The influence of various drugs on the binding of tianeptine to human plasma proteins.

The plasma binding of the atypical tricyclic antidepressant tianeptine was studied in combination with six drugs, at therapeutic concentrations: cyamemazine, levomepromazine, flunitrazepam, oxazepam, diclofenac and salicylic acid. Of these drugs, only salicylic acid at high plasma concentrations impaired tianeptine binding and thus may potentiate its effects.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1991

[Is the plasma protein binding of lidocaine modified by the simultaneous administration of midazolam?].

Perioperative antiarrhythmic therapy with lidocaine (bolus dosage 100 mg followed by infusion of 200 mg/h) was performed in 24 patients; 12 of them simultaneously received an intravenous injection of 10 mg midazolam with the bolus of lidocaine (group I: with midazolam; group II: without midazolam). Central venous blood samples were collected over a period of 1 h (1, 3, 5, 10, 20, 30, and 60 min after the bolus) to evaluate unbound and total (protein-bound + unbound) plasma concentrations of lidocaine, thus calculating plasma protein binding. One minute after intravenous administration of lidocaine peak plasma concentrations occurred: in group I 5.38 +/- 1.99 micrograms/ml (mean +/- SD), in group II 5.25 +/- 1.90. Up to 60 min there was only a gradual decrease in plasma concentrations in both groups. There was no significant difference between the two groups (group I: mean free concentration 0.67-0.80 micrograms/ml; mean total concentration 4.84-5.38 micrograms/ml; mean plasma protein binding 83%-86%; group II: 0.69-0.89 micrograms/ml; 4.62-5.25 micrograms/ml; 82%-85%). We draw the conclusion that midazolam administration is safe in patients undergoing antiarrhythmic therapy or regional anesthesia with lidocaine.

Adult↗
PubMed2003

Selection of the dominant follicle and insulin-like growth factor (IGF)-binding proteins: evidence that pregnancy-associated plasma protein A contributes to proteolysis of IGF-binding protein 5 in bovine follicular fluid.

Development of a dominant follicle is associated with decreased intrafollicular low molecular weight IGF-binding proteins (namely IGFBP-2, -4, and -5) and increased proteolysis of IGFBP-4 by pregnancy-associated plasma protein A (PAPP-A). In addition to IGFBP-4 proteolytic activity, bovine follicular fluid contains strong proteolytic activity for IGFBP-5, but not for IGFBP-2. Here we show that the IGFBP-5 protease present in bovine follicular fluid is a neutral/basic pH-favoring, Zn(2+) metalloprotease very similar to the previously described IGFBP-4 protease. We hypothesized that immunoneutralization and immunoprecipitation with anti-PAPP-A antibodies would result in abrogation of the IGFBP-4, but not the IGFBP-5, proteolytic activity in follicular fluid. As expected, anti-PAPP-A antibodies were able to neutralize and precipitate the IGFBP-4, but not the IGFBP-5, proteolytic activity of human pregnancy serum, which was used as a positive control for PAPP-A. Surprisingly, immunoneutralization and immunoprecipitation of follicular fluid from bovine preovulatory follicles with anti-PAPP-A antibodies abrogated both IGFBP-4 and IGFBP-5 proteolysis. Quantitative results derived from phosphorimaging revealed a complete inhibition of both IGFBP-4 and -5 proteolysis by follicular fluid incubated for 2 or 5 h in the presence of anti-PAPP-A antibodies. After 18 h of incubation, anti-PAPP-A antibodies still inhibited IGFBP-5 degradation, although with an efficiency lower than that for IGFBP-4 degradation. Both proteolytic activities have identical electrophoretic mobility, and a single band ( approximately 400 kDa) was detected by Western immunoblotting of bovine follicular fluid with anti-PAPP-A antibodies. Proteolysis of IGFBP-5 was readily detectable in follicular fluid from dominant follicles and was negligible in subordinate follicles from the same cohort. These results suggest that an active intrafollicular IGFBP-4/-5 proteolytic system, in which PAPP-A is the major protease involved, is an important determinant of follicular fate.

Animals↗
PubMed1993

Plasma protein levels in normal human fetuses: 13 to 41 weeks' gestation.

OBJECTIVES: To establish reference ranges for the levels of alpha-fetoprotein, albumin, prealbumin (transthyretin) alpha-1-antitrypsin, transferrin, ceruloplasmin and total protein in the plasma of normal human fetuses and newborn babies. DESIGN: Prospective study of individual normal cases to fulfil objectives. SETTING: Pathology laboratories of the University of Edinburgh and the biochemistry laboratories of the University of Keele. SUBJECTS: Twenty-two normal fetuses 13 to 22 weeks of gestation and 66 babies born between 24 and 41 weeks gestation. RESULTS: Albumin is the predominant plasma protein throughout gestation. The levels of alpha-fetoprotein and prealbumin fell significantly with increasing gestation, whereas the concentrations of the other proteins studied increased. The ratios of individual proteins to total protein demonstrated similar trends. CONCLUSIONS: This study provides developmental profiles of normal human fetal plasma proteins to serve as possible reference data for abnormal fetuses. Declining levels of prealbumin (transthyretin) were unexpected and suggest a functional role for this protein in early pregnancy.

Blood Proteins↗
PubMedDate not supplied

[Blood plasma protein metabolism in ground squirrels in various stages of hibernation].

Synthesis intensity and a spectrum of synthetized proteins of blood plasma in the gophers at different hibernation stages (hibernation, awakening, being awake) were studied. It is established that the organism of hibernating animals has a constant concentration of plasma proteins during the whole period of the winter hibernation. Selective activation of synthesis of certain groups of plasma proteins is observed at different stages of hibernation in gophers and certain amount of specific proteins appear.

Animals↗