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PubMed1984

Immunohistochemical identification of some plasma proteins in human embryonic and fetal forebrain with particular reference to the development of the neocortex.

The histogenesis of the cerebral neocortex has been studied in human embryos and fetuses from the ventricular zone stage at 9-10 mm crown-rump length (CRL) to the well-developed neocortex at 210 mm CRL. The initial proliferation of the neuroepithelial cells in the ventricular zone stage was followed by a stage characterized by a ventricular zone covered by a primordial plexiform layer; the subventricular zone then arose before the cortical plate was formed within the primordial plexiform layer, thus dividing it into an outer marginal zone and an inner subplate zone; finally the intermediate zone appeared between the subventricular and subplate zones. The distribution of cells containing albumin, alpha-fetoprotein, transferrin, prealbumin, IgG and alpha 1-antitrypsin in the cerebral vesicle and developing neocortex was investigated by the indirect immunoperoxidase technique. Alpha-fetoprotein found in the cells of the ventricular zone was the most widespread and prominent of the plasma proteins examined in the early embryos. The cerebral vesicle was negative for all other plasma proteins investigated at this stage. By 15 and 16 mm CRL, a few cells in the ventricular zone were positive for albumin and transferrin whereas AFP exhibited a distribution similar to that of the 9 mm embryo. By 20-25 mm CRL, albumin and AFP had a similar distribution in the telencephalic wall. At 40-150 mm CRL a positive staining reaction for AFP, albumin, prealbumin and transferrin was predominant in the outer half of cortical plate. At 150-170 mm CRL only cells in the inner half exhibited positive staining and at 210 mm CRL the staining reactions were negative. The cells containing plasma proteins did not belong to a single cell line or type; thus plasma proteins were detected primarily in different types of neurons but also in glial cells. Staining with polyvalent antiserum indicated that the same cells may be positive for more than one plasma protein. Positive staining reactions were also observed in or along fiber systems. It is proposed that cells initially take up plasma protein from the CSF and migrate with it towards the cortical plate. After a certain period they lose their plasma protein but when the neuronal cells which represent the majority of the positively stained cells have reached their final position in the cortical plate they commence plasma protein synthesis which continues for a short period during which the neurons establish their pattern of connectivity.

Blood Proteins↗
PubMed2001

Influence of adsorbed plasma proteins on erythrocyte rheological properties: in vitro and ex vivo studies.

The influence of plasma protein adsorption on the mechanical properties characterizing erythrocyte behaviour under flow was studied in human and rats. The deformability index, elastic modulus and surface viscosity were measured by laser diffractometry. In in vitro studies, human and rat erythrocytes were washed to remove their original protein coating, and then incubated in saline-diluted plasma media. For erythrocytes incubated in the most diluted solutions (plasma/saline 1:3, v/v), the deformability index increased 30% for both species (human, P<0.01 and rat, P<0.2); the elastic modulus decreased 20% (human, P<0.05) and 60% (rat, P<0.01); and surface viscosity decreased 20% (human, P<0.05) and 40% (rat, P<0.01), relative to values for erythrocytes incubated in pure plasma. Ex vivo experiments were performed using rats. Plasma proteins were diluted replacing 15% volemic plasma by saline in three consecutive plasmapheresis steps. The rheological properties of erythrocytes, tested after each step, followed the general trends of the in vitro pattern. These results suggest that the decrease in plasma protein concentration affects blood rheology in two ways. The first is the well known decrease in plasma viscosity, and the second is an improvement of erythrocyte deformability, as has been shown in this work. Thus, a new argument supporting the benefits of normovolemic hemodilution in patients with poor peripheral perfusion is provided.

Adsorption↗
PubMed1978

[Effect of non-steroidal anti-inflammatory drugs on plasma protein binding of corticosterones (author's transl)].

A series of non-steroid antiinflammatory drugs (NSAD) as well as substances with different spectra of pharmacological action were investigated with regard to the influence on binding of corticosterone to plasma protein in rats after repeated oral administration. At pharmacologically active doses, NSAD cause a time and dose dependent increase in rat plasma of the corticosterone fraction which can be ultra-filtrated. The effect on corticosterone binding to plasma protein largely parallels the antiinflammatory efficacy of the NSAD. This does not occur by a mere displacement of corticosterone from the plasma protein binding, but is apparently the consequence of a qualitative and/or quantitative change of the binding proteins. Organic acids, cytostatic or other drugs which strongly bind to plasma protein do not show any corresponding influence on the corticosterone binding to plasma protein under comparable conditions. The increase of the fraction of corticosterone which can be ultra-filtrated effected by the NSAD accelerates the excretion of corticosterone into the bile of rats. The phenomenon of decrease in binding of corticosteroids to plasma protein is discussed with respect to its importance for the mode of action of the NSAD.

Administration, Oral↗
PubMed1990

[Chemistry and clinical significance of human plasma proteins].

Enormous progress has been made in the course of the past few years in the various fields of plasma protein research. The primary and disulfide bridge structures are now known for almost all of the 120 proteins thus far isolated from human plasma, including trace and ultratrace proteins as well as a number of genetic variants. Genetic cloning and the derivation of the amino-acid sequence from the nucleotide sequence have played a decisive role here. However, we are only in possession of the exact three-dimensional structure for a small number of plasma proteins. The major problem in this respect is, at present, the lack of suitable protein crystals for X-ray structure analysis. We still do not know the physiological function of a large number of plasma proteins, despite the fact that they, in part, have been well characterised both physically and chemically and could be assigned to their respective protein families on the basis of their amino-acid sequence. The development of techniques for protein structure determination is relatively well advanced today, yet we lack methods of illuminating the structure-function relationship. There are more than 20 different highly purified protein preparations in virus-safe form available today for substitution therapy. To this effect new purification procedures have been developed which pay particular attention to virus elimination and inactivation. Should present indications be confirmed, one may assume that further plasma proteins (e. g. proteinase inhibitors, apolipoproteins, fibronectin) could be of significance in therapy and prophylaxis. Unlimited amounts of human blood are not available. Gene technology offers a promising alternative, at least for the production of plasma protein administered to patients in small amounts. Work is being done intensively on various blood coagulation factors and proteinase inhibitors at the moment, and factor VIII: C is already being successfully used for the treatment of patients with hemophilia A. However, it will no doubt take years before recombinant plasma proteins are in a position to extensively replace traditional preparations. In the field of diagnostic investigation with plasma proteins immunochemical methods of determination have assumed an increasing significance during the course of the last two decades. Particularly the development of automated techniques which allow serial quantification of individual proteins, has made protein profiling for diagnosis and monitoring in a number of diseases a routine procedure in many clinical laboratories.

Amino Acid Sequence↗
PubMed1978

Increased plasma protein binding of propranolol and chlorpromazine mediated by disease-induced elevations of plasma alpha1 acid glycoprotein.

To assess the importance of disease-induced increases in plasma concentrations of alpha1 acid glycoprotein (an acute-phase plasma protein that binds cationic drugs), we determined binding of propranolol in plasma from 53 patients and 25 healthy volunteers. Binding was increased in 10 patients with Crohn's disease (P less than 0.002), nine with inflammatory arthritis (P less than 0.002) and eight with chronic renal failure with superimposed inflammatory disease (P less than 0.01) as compared with healthy controls. The plasma binding of control subjects did not differ from that of 12 patients with chronic hepatic disease (P greater than 0.45) or 14 with uncomplicated renal failure (P greater than 0.80). Chlorpromazine binding, determined in 60 subjects, yielded similar results. Percentage of free drug and alpha1 acid glycoprotein concentration were inversely correlated (r = -0.77 with propranolol, P less than 0.001, and r = -0.69 with chlorpromazine, P less than 0.001). Increases in plasma protein binding in patients with inflammatory disease appear mediated by increases in alpha1 acid glycoprotein concentration, which may influence drug kinetics.

Adult↗
PubMed1990

The role of plasma protein binding on the metabolism and renal excretion of sulphadimethoxine and its metabolite N4-acetylsulphadimethoxine in pigs.

The effects of plasma protein binding on the elimination of sulphadimethoxine (SDM) were examined after intravenous administration of 6.25, 12.5, 25, 50, 100 and 150 mg/kg to pigs. At an early stage of the experiment, the animals were anaesthetised by inhalation of enflurane to obtain a more exact relationship between plasma concentration and the renal excretion. SDM and its acetylated conjugate, N4-acetylsulphadimethoxine (N4-SDM) were detected in plasma and urine of all animals, and the recovery of the doses was almost complete in two animals with negligible renal excretion of SDM. The percentages of plasma protein binding of SDM and N4-SDM were almost similar, and ranged from 30 to 95%, depending on the plasma concentration. The metabolic clearance of SDM by acetylation increased when the plasma protein binding decreased. These results suggested that the main elimination route of SDM in pigs is acetylation, and that the plasma protein binding can have a large effect on the elimination of SDM in pigs. The effect of plasma protein binding on the renal clearance of SDM was not so evident, because urine pH had a much greater effect on it. The deacetylation of N4-SDM was detected after 25 mg/kg intravenous administration of N4-SDM, which suggests that the metabolic clearance of SDM is part of an acetylation-deacetylation equilibrium. Saturation of the active tubular reabsorption of SDM and of the active tubular secretion of N4-SDM was also suggested after higher doses of SDM.

Acetylation↗
PubMed1981

Interaction of calcium with bovine plasma protein C.

The binding of 45Ca2+ to bovine plasma protein C (PC) and to activated bovine plasma protein C (APC) has been examined by equilibrium ultrafiltration at pH 7.4 and 25 degrees C. Under these conditions, PC possesses 16.0 plus or minus 2.0 equivalent Ca2+ binding sites, of average KD (8.7 plus or minus 1.5) x 10(-4) M, and APC contains 9.0 plus or minus 1.0 equivalent Ca2+ binding sites, with an average KD of (4.3 plus or minus 1.1) x 10(-4) M. Both Mn2+ and Sr2+ were capable of ready displacement of Ca2+ from a Ca2+-PC complex, while Mg2+ was less effective in this regard. The alpha-thrombin-catalyzed activation of PC was inhibited by the presence of Ca2+. A kinetic analysis of this effect demonstrated that it was, in large part, due to an increase in the Km of the reaction. Addition of other divalent cations, e.g. Mn2+, Sr2+, and Mg2+, in place of Ca2+ also resulted in inhibition of the alpha-thrombin-catalyzed activation of PC in a manner which paralleled their ability to displace Ca2+ from a Ca2+-PC complex. On the other hand, the activation of PC by the coagulant protein from Russell's Viper venom was augmented by the presence of Ca2+. Other divalent metal ions, such as Sr2+ and Mn2+, in the absence of Ca2+, also weakly stimulated this reaction. Mg2+ was without notable effect.

Animals↗
PubMed1999

[Vroman effect of plasma protein adsorption to biomaterials surfaces].

Fibrinogen adsorption from plasma to biomaterials surfaces passes through a maximum when studied as a function of adsorption time, plasma concentration, or column height in narrow spaces and these are called Vroman effect. Studies have demonstrated that Vroman effect is a general phenomenon of plasma proteins and reflects the competitive adsorption of plasma proteins for a limited number of surface sites. In this paper, the factors affecting Vroman effect, the relationship between contact activation and fibrinogen displacement, and the significance of the Vroman effect with respect to blood-material interactions are reviewed.

Adsorption↗
PubMed1992

Dose-dependent inhibition in plasma protein binding of valproic acid during continued treatment in guinea-pigs.

Plasma protein binding of valproic acid over a wide range of steady-state plasma concentration (11.3 +/- 2.6-1303.0 +/- 122.9 micrograms mL-1: s.e.m., n = 5) in guinea-pigs has been studied. Valproic acid was given by intravenous constant infusion. At steady-state the plasma protein binding of valproic acid was analysed. Nonlinear binding was observed. Unbound fraction (fu) of valproic acid increased from 25 to 95% with the increase of steady-state plasma concentration (Css). The plasma protein-bound drug concentration (Cb) of valproic acid increased initially with Css but decreased after the Css exceeded 345.0 micrograms mL-1, where the Cb was 152.5 +/- 26.8 micrograms mL-1. At a Css of 1303.3 +/- 122.9 micrograms mL-1 the Cb was significantly (P less than 0.05) decreased to 72.8 +/- 20.2 micrograms mL-1. Binding characteristics of valproic acid in-vitro were studied using drug-free guinea-pig plasma with added valproic acid (10-1000 micrograms mL-1). The binding behaviour was also nonlinear in-vitro. The fu increased from 14 to 79% with the increase of valproate concentrations. No decrease in Cb was observed throughout the range. The study demonstrated that binding characteristics of valproic acid in-vivo and in-vitro are not parallel. The results suggest that valproic acid may produce or induce plasma protein binding competitors; metabolites of valproic acid may be implicated.

Animals↗
PubMed1991

'Lens-on-surface': a versatile method for the investigation of plasma protein exchange reactions on solid surfaces.

The exchange sequence of plasma proteins in narrow spaces on solid surfaces was studied by means of a modified 'lens-on-surface' method as originally described by Vroman and Adams. In our studies, lateral scanning ellipsometry was used as the detection method. With the use of antibodies it was demonstrated and confirmed that immunologically detectable plasma protein antigens appear and disappear in a time- and concentration-dependent sequence [IgG followed by fibrinogen followed by high-molecular weight kininogen (HMWK)] on silica surfaces. Plasma protein exchange reactions were also studied on hydrophilic titanium (Ti), vanadium (V), and silver (Ag) surfaces. Atypical exchange patterns were found on V and Ag surfaces as compared with hydrophilic silica (adsorbed fibrinogen was not removed).

Adsorption↗
PubMed1994

Characteristics of plasma protein binding of tacrine hydrochloride: a new drug for Alzheimer's disease.

The aim of this study was to characterise the plasma protein binding of tacrine hydrochloride (THA) in vitro. Binding was assessed in the plasma of 11 healthy individuals aged 20 to 27 years using ultrafiltration followed by HPLC assay. At THA concentrations from 10 to 100 ng/ml protein binding ranged from 78.6 to 71.0%. Binding to commercially available human albumin ranged from 41.7 to 38.3% and to human alpha 1-acid glycoprotein from 23.1 to 12.4% over the THA concentrations from 25 to 100 ng/ml. THA binding and total plasma protein, plasma albumin and alpha 1-acid glycoprotein were measured in healthy young subjects (n = 13), healthy elderly individuals (n = 12) and patients hospitalised with acute illnesses (n = 8). There were significant differences between the groups in total plasma protein, plasma albumin and in alpha 1-acid glycoprotein but no differences in the protein binding of THA which remained constant at about 75%. There was no correlation between THA binding and any plasma protein concentration. The THA binding was not high enough to be of major significance clinically or to reduce the validity of total plasma THA measurement in therapeutic monitoring.

Adolescent↗
PubMed1999

Biosynthesis of major plasma proteins in the primary culture of fat body cells from the silkworm, Bombyx mori.

Plasma proteins termed "SP1" and "30K proteins" are synthesized by the fat body cells of the silkworm, Bombyx mori, in a sex- and stage-specific manner during larval development. We successfully established a primary culture of the fat body cells in order to investigate the regulatory mechanisms of plasma protein gene expression. The primary cultures of fat body cells contained at least two cell types: small oval cells, and large spherical cells. The cells adhered to and migrated on the cultured dish after plating. By the 7th day of cultivation, the cells clustered to form fat body-like structures, which were maintained for at least 3 months. Plasma proteins were actively synthesized in the primary cultures of the fat body cells isolated from the final instar larvae only when the cells tightly adhered to and clustered on the cultured dish. Immunocytochemical analysis revealed that only 10-15% of the clustered cells synthesized plasma proteins in our culture system, indicating that the primary culture comprises heterogeneous cells that are morphologically and functionally distinct. The patterns of SP1 syntheses in primary cultures faithfully reproduced their sex-dependency in vivo.

Animals↗
PubMed1985

Vasomotion and transvascular exchange of fluid and plasma proteins.

The effect of spontaneous arteriolar vasomotion on the transvascular exchange of fluid and plasma proteins has been studied theoretically. The model combines fluid dynamic principles with a phenomenological approach to transvascular exchange on the basis of irreversible thermodynamics. The analytical treatment of the intravascular flow together with consideration of local changes of the morphology and vascular membrane characteristics makes it possible to determine the spatial and temporal variation of transvascular fluid and plasma protein fluxes. Since the undulations of the arteriolar diameter have low frequencies (3 to 10 per cycle), the transvascular fluxes are in phase with the vasomotion. The model combines hemodynamics, microhemorheology and mass transfer at the vessel wall and provides pressures, velocities, plasma protein concentration, hematocrit and apparent blood viscosity at any position in the microvascular bed at any time. In addition, global parameters as the total filtration rate and the total transvascular mass flow rate of plasma proteins are determined as functions of time. Numerical results are obtained for the cat mesentery with the terminal arteriole exhibiting vasomotion. The vascular arrangement studied comprised a terminal arteriole, capillaries and a venule together with appropriate side branches. The results show dramatic temporal changes in the hemodynamic parameters. Fluid filtration occurs along the entire vascular length at all times except during vasoconstriction when small absorption rates occur on the venous side. The transvascular fluxes achieve maximum values either on the arteriolar or on the venular side depending on the moment of the vasomotion cycle. The transvascular exchange rates in the mid-capillaries are generally low.

Animals↗
PubMed1997

Role of sensory innervation and mast cells in neurogenic plasma protein exudation into the airway lumen.

Neurogenic inflammation in the airways involves both mucosal oedema and plasma protein exudation into the airway lumen. We aimed to investigate the mechanism of exudation of plasma proteins into the airway lumen. Neurogenic inflammation was induced in anaesthetized Sprague-Dawley rats by electrical stimulation of both vagal nerves at 20 V, 10 Hz, 5 ms. Vascular permeability was measured as 125I-albumin extravasation into both the airway wall and tracheobronchial lavage fluid. Following vagal stimulation, tracheobronchial lavages were analysed for albumin, total protein, histamine, immunoreactive substance P (SP), and immunoreactive calcitonin gene-related peptide (CGRP). Vagal stimulation rapidly increased vascular permeability in the airway mucosa and induced exudation of plasma proteins into the tracheobronchial fluid. Pre-treatment with capsaicin inhibited both neurogenic vascular permeability and movement of albumin into the airway lumen. SP and CGRP were detectable in basal lavages (1.37+/-0.12 ng/mL and 2.17+/-0.21 ng/mL, respectively) and the concentration of SP fell by 43% following treatment with capsaicin. Following vagal stimulation, concentrations of both SP and CGRP decreased significantly. Although basal tracheobronchial lavages contained histamine, vagal stimulation did not increase the histamine concentration. These results indicate that both neurogenic vascular permeability and plasma protein exudation into the airway lumen results from activation of capsaicin-sensitive sensory nerves and the reaction is not associated with mast cell activation.

Analysis of Variance↗
PubMed1990

Flavone acetic acid and plasma protein binding.

Both the capacity of healthy human, cancer patient, and mouse plasma proteins to bind flavone acetic acid (FAA) and the qualitative differences in the plasma protein-binding site were studied. The binding capacity of plasma proteins for FAA was saturated within the therapeutic range in both species. The binding of FAA to plasma protein was significantly greater in both healthy human and cancer patient plasma than in mouse plasma. Plasma from patients with cancer bound on the average less FAA than did healthy patient plasma. The concentration of albumin in the plasma varied between healthy humans, cancer patients, and mice, being 5.3 +/- 0.7, 4.7 +/- 0.8, and 3.9 +/- 0.3 g/100 ml, respectively. The protein binding of FAA was found to be dependent on the plasma albumin concentration, but albumin concentration alone was not adequate for the accurate prediction of the percentage of FAA protein bound. Scatchard plots indicated that healthy human plasma had a greater number of high-affinity binding sites than did mouse plasma. FAA binds at the indolebenzodiazepine binding area on albumin and can be displaced from this site by salicylic acid and clofibric acid, but only at supratherapeutic concentrations. Our results indicate that alterations in plasma albumin could contribute to a variable effect with FAA. Therefore, the influence of serum albumin concentration and the nonlinearity of FAA protein binding should be considered in assessment of the appropriateness of a dose schedule for FAA.

Animals↗
PubMed1995

Human placental lactogen and pregnancy-associated plasma protein A in first trimester and subsequent fetal growth.

OBJECTIVE: To study in an optimized design the possible relation between serum levels in weeks 8-14 of human placental lactogen and pregnancy-associated plasma protein A and fetal size at delivery. METHODS: Analysis of data from 93 normal singleton pregnancies. Gestational age was assessed from a sonographic crown-rump length measurement. Serum levels of human placental lactogen and pregnancy-associated plasma protein A were determined by radioimmunoassay, and were expressed in multiples of mean. The relative birth weight was used as an index of fetal growth. RESULTS: Serum levels of human placental lactogen and pregnancy-associated plasma protein A showed a negative correlation to gestational age at delivery (p < 0.01 and p < 0.05, respectively), and there was a positive correlation between the serum level of pregnancy-associated plasma protein A and relative birth weight (p < 0.02). CONCLUSIONS: Higher levels of human placental lactogen and pregnancy-associated plasma protein A predicted earlier delivery, maybe because of better fetal growth, and higher levels of pregnancy-associated plasma protein A predicted better fetal growth.

Birth Weight↗
PubMed1985

Messenger ribonucleic acid (mRNA) from developing rat cerebellum directs in vitro synthesis of plasma proteins.

Poly(A)-containing messenger RNA from different ages of postnatal rat cerebellum was translated in the reticulocyte lysate system, using [35S]methionine to label newly synthesized polypeptides. Translation products were identified using crossed immunoelectrophoresis and antisera against whole rat plasma and/or specific plasma proteins, followed by autoradiography. It was found that postnatal cerebellar mRNA directs the synthesis of low density lipoprotein (LDL), fibrinogen, transferrin, alpha 1-macroglobulin, alpha 2-macroglobulin and probably also alpha-fetoprotein, albumin and alpha 1-lipoprotein. mRNAs for several other yet undefined plasma proteins were also detected. In general, the synthesis of plasma proteins appeared to decline with cerebellar maturation. X-irradiation or hypothyroidism resulted in selective changes in the levels of mRNA-directed plasma proteins. In the X-irradiated cerebellum these included an increase in the level of mRNA for alpha-fetoprotein and a decrease in the level of mRNA for fibrinogen. In contrast, hypothyroidism decreased cerebellar plasma protein synthesis in general. These observations indicate that plasma proteins are actively produced within the developing rat cerebellum, and that the rate of their synthesis depends on the developmental stage and is influenced by the types of cells present.

Age Factors↗
PubMed2002

On the active vascular absorption of plasma proteins from tissue: rethinking the role of the lymphatic system.

According to Starling's hypothesis, the osmotic pressure of plasma proteins in the capillary is the principal force for fluid absorption. The leakage of plasma proteins from capillaries to tissue during 24 h accounts for the total amount of plasma proteins in the vascular system. The same amount must therefore be reabsorbed by the lymphatic system, which is considered to be the sole absorber of proteins from tissue. However, it is a well-established routine in all kinds of organ transplantation to not restore the lymphatic system of the transplant. Experience has shown that this reconstruction is unnecessary, which consequently implies that the lymphatics are not of crucial importance for the survival of the organ. Inevitably, we must therefore question the vital role that the lymphatic system has been attributed in maintaining homeostasis as the sole absorber of proteins. Instead, it is proposed that the major part of plasma proteins in tissue is actively absorbed by the capillaries.

Absorption↗