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PubMedDate not supplied

Plasma protein changes in primary hypertension in humans and rats.

To determine whether plasma protein changes may be associated with primary hypertension, we analyzed plasma proteins from essential hypertensive (EHT) patients and genetically hypertensive rats using two-dimensional electrophoresis. An additional plasma protein, having a molecular weight of 13,000 daltons and an isoelectric point of 4.5, was found in 82% of the patients with borderline or moderate hypertension (n = 29) and in all permanently hypertensive patients (n = 12). This protein was detected in 36% of normotensive (NT) subjects (n = 50). In the latter, the influence of family history, sex, and secondary hypertension were studied. Plasma proteins were also studied in spontaneously hypertensive rats (SHR). In all plasma from young male (n = 10) and female (n = 6) SHR, two additional proteins (molecular weight = 16,000 daltons, pHi = 4.7 and 5.1) were detectable. These plasma proteins were not detectable in male Wistar Kyoto rats (WKY) and in 50% of female WKY, and their frequency was 10% (n = 10) and 0% (n = 3) in normal male WKY and in male WKY rendered hypertensive by methylprednisolone, respectively. We conclude that these alterations of plasma proteins may be considered a biochemical feature of primary hypertension.

Adolescent↗
PubMed1998

Interaction of bull, stallion and boar seminal plasma proteins and sperms with acidic polysaccharides.

The interaction of seminal plasma proteins, sperms and detergent-released sperm proteins of three species with different types of acidic polysaccharides was studied. Heparin-binding activity of boar, bull and stallion seminal plasma proteins, sperms and sperm proteins was compared with their ability to interact with polysaccharides differing in the presence of the sulfate groups or in their saccharide moiety (chondroitin sulfate, dextran sulfate, fucoidan, hyaluronic acid). Bull seminal plasma proteins were characterized by higher affinity to heparin, fucoidan and dextran sulfate, while significant differences between different types of polysaccharides were detected in the case of boar proteins. Sperm protein interactions with acidic polysaccharides in bull and stallion were analogous to the binding of seminal plasma proteins. Bull and stallion seminal plasma proteins inhibited the interaction of corresponding sperm proteins with acidic polysaccharides.

Animals↗
PubMed1976

Osmotic interaction of plasma proteins with interstitial macromolecules.

The osmotic interaction of plasma proteins with collagen and hyaluronate has been evaluated by measuring the oncotic pressure of mixed solutions of varying composition. Collagen, despite its insolubility, exhibits a pronounced volume exclusion effect on plasma proteins, and the oncotic pressure of mixed solutions is considerably higher than that of the plasma protein stock solution. The volume exclusion of collagen on small molecules such as sucrose is negligible. A solution composed of 1.6% plasma proteins, 20% collagen, and .4% hyaluronate in Ringer solution, approximating the composition of the interstitium, was found to yield higher oncotic pressures than those previously reported from the interstitium. The probable role of impurities and degradation in the isolation process is discussed. Results reported earlier from in vitro and in vivo studies indicated that tissue oncotic pressures are considerably higher than generally recognized and that tissue fluid is in probable osmotic equilibrium with lymph in skin and muscle.

Collagen↗
PubMed2002

Seminal plasma proteins reduce protein tyrosine phosphorylation in the plasma membrane of cold-shocked ram spermatozoa.

Capacitation of spermatozoa, a complex process occurring after sperm ejaculation, is required to produce fertilization of the oocyte in vivo and in vitro. Although this process results from a poorly understood series of morphological and molecular events, protein tyrosine phosphorylation has been associated with sperm capacitation in several mammalian species, but it still remains to be demonstrated in ram spermatozoa. Studies of capacitation in ram spermatozoa are of great interest, since several reports have suggested that the reduced fertility of cryopreserved spermatozoa is due to their premature capacitation. In this work, we report for the first time, to our knowledge, that tyrosine phosphorylation of ram sperm membrane proteins is related to the capacitation state of these cells. Capacitation induced tyrosine phosphorylation of some plasma membrane proteins of ram spermatozoa freed from seminal plasma by a dextran/swim-up procedure. It has also been proved that cold-shock induces protein tyrosine phosphorylation as well as a decrease in plasma membrane integrity. Addition of seminal plasma proteins prior to cold-shock not only improved sperm survival but also promoted a decrease in protein tyrosine phosphorylation.

Animals↗
PubMed1986

Measurement of the pregnancy-associated proteins, placental protein 14 and pregnancy-associated plasma protein A in human seminal plasma.

The pregnancy-associated and placental proteins PP14 and PAPP-A have been measured in human seminal plasma from normal men. PP14 was a significant protein constituent in most seminal plasma samples; sometimes comprising over 2.5% of the total protein content. The concentration of PP14 in seminal plasma from men with oligospermia was in the reference range of this protein derived from values measured in normal men. However, about 14% of samples from vasectomized subjects contained concentrations of PP14 less than normal. It was found that the concentration of PAPP-A in seminal plasma from vasectomized men and men with oligospermia also fell within the reference range for this protein. However, the concentration of PAPP-A in seminal plasma was significantly higher in those subjects whose sperm motility was above 60% than in those with a lower percentage motility, suggesting a possible role of this protein in sperm function.

Glycodelin↗
PubMed1977

Effect of local anesthetics on plasma protein secretion by rat hepatocytes.

The effects of some local anesthetics on plasma protein secretion by rat liver slices have been studied and have been compared with those of colchicine. Rat liver slices were pulse-labelled with L-[14C]leucine for 9 min at 37 degrees C, collected on filter paper, washed with non-radioactive leucine and reincubated in the presence or absence of the drug to be tested. The radioactive plasma proteins produced were obtained by immunoprecipitation from either the chase medium or from the washed slices. Chlorpromazine, (3.10(-5) M), dibucaine (10(-5) M), lidocaine (10(-3) M) and procaine (5.10(-5) M) inhibited both the synthesis and secretion of plasma protein but did not affect the uptake of L-leucine into the slices nor the incorporation of phosphate into intracellular nucleotide phosphates or into phospholipids. The inhibition of secretion elicited by these drugs is probably not due to the inhibition of protein synthesis since cycloheximide, when added to the chase medium at a concentration which completely inhibits protein synthesis, did not inhibit plasma protein secretion, while cycloheximide plus procaine did inhibit secretion and also caused a retention of non-secreted plasma proteins within the slices. Unlike colchicine, however, procaine did not cause the retained plasma proteins to accumulate in Golgi-derived secretory vesicles, but showed a more general effect causing a distribution among several cell fractions.

Anesthetics, Local↗
PubMed1984

Effect of concentration-dependent binding to plasma proteins on the pharmacokinetics and pharmacodynamics of disopyramide.

Disopyramide exhibits concentration-dependent binding to plasma proteins at therapeutic plasma concentrations. This paper reviews the effect of this type of binding on both the pharmacokinetic and pharmacodynamic properties of the drug. For a drug with capacity-limited, binding-sensitive elimination like disopyramide, concentration-dependent binding to plasma proteins produces a non-linear relationship between dosing rate and total plasma concentrations of the drug. However, when dosing rate is related to unbound concentrations of drug, the relationship is linear. Renal clearance of total disopyramide has been found to depend on the unbound fraction whereas renal clearance of unbound drug may be dependent upon time after drug administration as well as route of drug administration. However, due to some potential methodological problems, these data need verification. The concentration-dependent binding of disopyramide to plasma proteins, with its resultant effects on clearance and distribution, produces a concave curvature in the log unbound concentration versus time curves and a log-linear decline in total plasma concentration versus time after intravenous administration of the drug. Several pharmacological studies suggest that the unbound drug is active in terms of producing both desirable and undesirable effects. Hence, monitoring unbound concentrations of disopyramide seems more rational for clinical purposes. The few studies that have been carried out examining the optical isomers of disopyramide have suggested that both the pharmacokinetic and pharmacodynamic properties of the drug are stereoselective. Recent data reveal stereoselective binding to plasma proteins in humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Predicting plasma protein binding of drugs--revisited.

Plasma protein binding of drugs has been studied for almost 100 years, but despite the accumulation of large amounts of data, the accurate prediction of this ADME parameter continues to be problematic. This review outlines recent efforts on the development of prediction tools for plasma protein binding of drugs, specifically human serum albumin, in the context of its relevance and its influencing factors. The issue of why it is difficult to achieve prediction of sufficient quality for a diverse dataset will also be considered.

Blood Proteins↗
PubMed1987

Transvascular exchange of fluid and plasma proteins.

A theoretical model of transvascular exchange of fluid and plasma proteins in the microcirculation is developed based on fundamental laws of the fluid mechanics and on phenomenological transport equations of the irreversible thermodynamics. Intravascular axial changes of the pressure, flow and plasma protein concentration are taken into account as well as axial gradients of vascular permeability. Proper nondimensionalization of the resulting equations leads to the identification of dimensionless parameters which combine the transport characteristics of the endothelial wall and the intravascular flow resistance. In the theory, the dependence of the reflection coefficient on the transport coefficients of the vascular wall and on the plasma protein concentration is established. The model is applied to the cat mesentery and the rat intestinal muscle. The numerical simulations indicate that taking into account vascular protein permeability yields considerable differences in the axial distribution of the plasma protein concentration and transvascular fluxes in comparison with the case of protein impermeability of the endothelial wall. The results show that the maximum of the transvascular fluid and plasma protein movement resides at the site of the small venules while a minimum of the exchange occurs at the site of the midcapillaries.

Animals↗
PubMed1978

Hypotension associated with prekallikrein activator (Hageman-factor fragments) in plasma protein fraction.

Thirteen lots of plasma protein fraction made by one manufacturer were implicated in 23 recent reports of hypotension in surgical patients. Four of these patients required resuscitation after rapid administration of the product in the postoperative period. All implicated lots had prekallikrein-activator activity but low levels of bradykinin and kallikrein. The prekallikrein activator was identified as Hageman-factor fragments by molecular weight (35,000 as estimated by gel chromatography), isoelectric point (4.2 to 4.4), and inhibition by antibody to Hageman factor. These data suggest that Hageman-factor fragments are potent hypotensive agents, presumably because they trigger the generation of bradykinin in recipients. Prekallikrein-activator activity, usually at levels lower than those in the initial 13 implicated lots, was frequently detected in plasma protein fraction made by other manufactures. Several of these lots were associated with additional reports of hypotension. Prekallikrein-activator activity rarely occurred in albumin.

Bradykinin↗
PubMed2000

Plasma protein thiol oxidation and carbonyl formation in chronic renal failure.

BACKGROUND: Myeloperoxidase-catalyzed oxidative pathways have recently been identified as an important cause of oxidant stress in uremia and hemodialysis (HD), and can lead to plasma protein oxidation. We have examined patterns of plasma protein oxidation in vitro in response to hydrogen peroxide (H2O2) and hypochlorous acid (HOCl). We measured thiol oxidation, amine oxidation, and carbonyl concentrations in patients on chronic maintenance HD compared with patients with chronic renal failure (CRF) and normal volunteers. We have also examined the effect of the dialysis procedure on plasma protein oxidation using biocompatible and bioincompatible membranes. METHODS: Plasma proteins were assayed for the level of free thiol groups using spectrophotometry, protein-associated carbonyl groups by enzyme-linked immunosorbent assay, and oxidation of free amine groups using a fluorescent spectrophotometer. RESULTS: In vitro experiments demonstrate HOCl oxidation of thiol groups and increased carbonyl formation. In vivo, there are significant differences in plasma-free thiol groups between normal volunteers (279 +/- 12 micromol/L), CRF patients (202 +/- 20 micromol/L, P = 0.005) and HD patients (178 +/- 18 micromol/L, P = 0.0001). There are also significant differences in plasma protein carbonyl groups between normal volunteers (0.76 +/- 0.51 micromol/L), CRF patients (13.73 +/- 4.45 micromol/L, P = 0.015), and HD patients (16.95 +/- 2.62 micromol/L, P = 0.0001). There are no significant differences in amine group oxidation. HD with both biocompatible and bioincompatible membranes restored plasma protein thiol groups to normal levels, while minimally affecting plasma protein carbonyl expression. CONCLUSIONS: First, both CRF and HD patients have increased plasma protein oxidation manifested by oxidation of thiol groups and formation of carbonyl groups. Second, HD with biocompatible and bioincompatible membranes restored plasma protein thiol groups to normal levels. Third, these experiments suggest that there is a dialyzable low molecular weight toxin found in uremia that is responsible for plasma protein oxidation.

Amines↗
PubMedDate not supplied

Rapid turnover transport proteins, plasma albumin, and growth in low birth weight infants.

The purpose of this investigation was to establish normative data and to determine the value of measuring rapid plasma turnover proteins in low birth weight infants during the neonatal period. Forty-three premature, adequate for gestational age infants were divided in three groups according to their birth weight: group A less than 1000 g, group B 1001 to 1500 g, group C 1501 to 2000 g. Weekly anthropometric measurements and biochemical determinations were obtained. Anthropometric measurements included weight, crown heel length, midtricipital skinfold thickness, and midarm circumference. Biochemical studies in plasma included total proteins, albumin, prealbumin, and retinol-binding protein. A significant increase in prealbumin concentration preceded weight gain. The elevation in prealbumin concentration was statistically significant (p less than 0.02) for the combined data from all groups and for infants included in group B and C (p less than 0.05). No concomitant changes were demonstrated in plasma retinol-binding protein, or total proteins. The transient rise in prealbumin plasma concentrations remains unexplained, but may be related to the infant's nutritional status.

Anthropometry↗
PubMed1986

Plasma proteinases, proteinase inhibitors and other selective plasma proteins following aortofemoral bypass operation.

Monitoring of plasma proteinases, proteinase inhibitors and other selective plasma proteins was evaluated in patients undergoing Y-graft aortofemoral bypass operation. Fast-reacting acute-phase proteins (C-reactive protein, antichymotrypsin, alpha 1-acid glycoprotein) and slow-reacting proteins (haptoglobin, alpha 1-antitrypsin) increased significantly 48-120 h after operation. By contrast, no significant increase was found between plasma ceruloplasmin levels before clamping and after declamping. Activity and concentration of alpha 2-macroglobulin decreased postoperatively and remained significantly lowered throughout the observation period. Plasma levels of granulocyte elastase were elevated significantly 1 h after declamping, whereas trypsin-binding capacity decreased immediately after the release of the clamp. Aprotinin pretreatment caused higher trypsin-binding capacity of the plasma, significantly lower 'unspecific' proteolytic (azocasein-hydrolyzing) activity and significantly lower non-TCA precipitable low molecular weight plasma protein concentration. Our results confirm the data of several authors that monitoring of plasma proteinases, proteinase inhibitors and other selective plasma proteins may be helpful in evaluating surgical patients postoperatively.

Adult↗
PubMed1993

Cellular delivery and retention of photofrin: III. Role of plasma proteins in photosensitizer clearance from cells.

Human plasma proteins, albumin, globulins and low density (LDL), high density (HDL) and very low density (VLDL) lipoproteins were tested for their effects on retention of Photofrin and three other photosensitizers in cultured cells. This was assessed by incubating the cells, subsequent to the exposure to Photofrin, in the photosensitizer-free medium containing various concentrations of different plasma proteins. Photofrin clearance levels differed with individual plasma proteins and also were dependent on concentration of these proteins in the incubation medium. All of the proteins except VLDL promoted clearance of Photofrin taken up by the cells in the presence of 5% human serum. Subsequent to some Photofrin exposure conditions (in the presence of 5% fetal bovine serum, or in protein-free medium), albumin, in contrast to LDL, HDL and globulins, exhibited decreased capacity for promoting the photosensitizer clearance from the cells. The VLDL showed very little or no effect in promoting cellular clearance of Photofrin, tetraphenyl porphine tetrasulfonate (TPPS4), and di- and tetrasulfonated chloroaluminum phthalocyanine (AlPcS2 and AlPcS4, respectively). The LDL seem to be particularly effective in promoting clearance of Photofrin and AlPcS2 from the cells, whereas albumin and globulins were shown to be more effective than LDL and HDL in promoting the cellular clearance of TPPS4.

Blood Proteins↗
PubMed1994

Differential susceptibility of plasma proteins to oxidative modification: examination by western blot immunoassay.

Plasma proteins are exposed to oxidants in a variety of circumstances in vivo, such as during tissue injury and inflammation. In this report, the relative susceptibility of each of the major plasma proteins to oxidative modification was assessed by exposing whole plasma to a metal-catalyzed radical generating system and detecting oxidation (protein carbonyl groups) using a novel Western blot immunoassay. Proteins were derivitized with dinitrophenylhydrazine, separated by SDS-gel electrophoresis, and screened with antibodies against dinitrophenyl groups. As little as 1 pmol of protein-associated carbonyls could be detected (100 ng of a 50 kD protein containing 0.5 mol carbonyl/mol protein). Individual plasma proteins were identified by their comigration with standards, crossreactivity with specific antibodies, and by comparison of plasma to serum. Using this approach, we found that plasma fibrinogen was much more susceptible to oxidative modification compared to the other major plasma proteins, albumin, immunoglobulins, and transferrin. The results emphasize the utility of this method for studying oxidation of proteins in cell extracts and tissues and indicate that experiments on the effects of oxidation on fibrinogen function are merited.

Animals↗
PubMed1983

Drug protein conjugates--VI. Role of glutathione in the metabolism of captopril and captopril plasma protein conjugates.

Previous metabolic studies of captopril suggest that the rapid dissociation of captopril-plasma protein conjugates in vivo is dependent upon endogenous thiols such as glutathione and cysteine. Consistent with this hypothesis, we have found that cysteine (0.06-3 mM) and glutathione (0.02-1 mM) cleave 14C-captopril-plasma protein conjugates in vitro. Dissociation of the drug-protein conjugate was accompanied by formation of the corresponding mixed disulphide which indicates that the reaction proceeds via a spontaneous thiol-disulphide interchange. Administration of high doses (50-300 mg/kg) of CP produced a time-dependent and dose-dependent decrease in hepatic glutathione concentrations in the mouse and the rat. The depletion of glutathione observed was similar to that produced by equimolar doses of D-penicillamine and paracetamol. Acute and chronic (7 days) administration of captopril (100 mg/kg) produces the same (11-12%) depletion of hepatic glutathione. However, changes in liver function as determined by elevation of serum glutamic-pyruvic transaminase was only observed at doses of 200 and 300 mg/kg. Thus, although thiol-disulphide interactions between captopril and plasma proteins may contribute to the perturbation of hepatic glutathione concentrations, it is unlikely that this process will be of toxicological significance during therapeutic administration of captopril.

Acetaminophen↗
PubMed1984

Effects of electroacupuncture on leukocytes and plasma protein in the X-irradiated rats.

The effects of electroacupuncture on leukocytes and plasma protein on the X ray-irradiated rats were investigated in the present study. The results showed that X-irradiation had an evident inhibitory effect on the counts of total leukocytes, lymphocytes and neutrocytes, and the concentration of the total plasma protein, plasma albumin, globulin and alpha- and beta-globulin in X-irradiated rats. The electroacupuncture was able to help the X-irradiated rats to recover the counts of the total leukocyte, lymphocyte and neutrocyte. The electroacupuncture had a helpful tendency to recover the concentration of the total plasma protein, albumin, globulin, and alpha- and beta-globulin in the irradiated rats.

Acupuncture Therapy↗
PubMed1992

Antibodies to plasma proteins: an association with platelet transfusion refractoriness.

We hypothesized that antibodies to HLA-linked polymorphic plasma proteins could be involved in platelet refractoriness by an 'innocent bystander' or immune complex mechanism. Employing a kinetic enzyme-linked immunosorbent assay (ELISA) technique the ability of IgG from the plasma of refractory patients to bind to albumin, fibrinogen, complement components C2 and C4 was measured. As compared with controls a high percentage of refractory patients had increased IgG capable of binding to all four plasma proteins: C2 (83%), C4 (83%), albumin (75%), fibrinogen (34%). In the presence of exogenous plasma proteins these antibodies mediated increased deposition of IgG onto normal donor platelets. The plasma protein binding IgG consisted both of monomeric IgG and a broad range of high molecular weight complexes. IgG anti-plasma protein antibody could be eluted from platelets of refractory patients. The development of anti-plasma protein IgG was studied during the course of platelet transfusion therapy and found to increase progressively so that by the 20th transfusion greater than 90% of samples were positive. The presence of plasma protein binding activity correlated with the development of increased levels of platelet bound IgG and refractoriness. Multiple platelet transfusions lead to sensitization to polymorphic determinants on C2 and C4 as well as the formation of high molecular weight complexes. These antibodies and complexes contribute to the deposition of IgG on platelets and may contribute to refractoriness.

Albumins↗