Biomedical subjects

E L Saenko

Publications and source records attributed to E L Saenko.

At least 55 records · Page 3Linked to original sources

PubMed1994

Modulatory effects of ceruloplasmin on lymphocytes, neutrophils and monocytes of patients with altered immune status.

We investigated the effect of plasma ceruloplasmin (Cp) on the different types of lymphocyte rosetting, and phagocytosis of polystyrene particles and culture Candida albicans by peripheral blood neutrophils and monocytes. Lymphocytes, neutrophils, and monocytes were isolated from the blood of patients with elevated immuno-status (n = 9), healthy donors (n = 21), and patients with reduced immuno-status (n = 21). The ability of Cp to decrease the number of lymphocytes forming E- and EAC-rosettes and rosettes with auto-erythrocytes was shown for both patients and healthy donors. The maximal decrease of the number of E-rosettes (by 35%) and EAC-rosettes (by 57%) was shown for lymphocytes of the patients with elevated immuno-status. Cp had an effect on rosetting only when lymphocytes were preincubated with it, suggesting that Cp binding to lymphocytes was responsible for these effects. The decrease in all types of rosetting caused by Cp was dose-related, with a maximum effect at physiological concentration of Cp (300 micrograms/ml). We demonstrated an enhancing effect of Cp on phagocytosis of Candida albicans and polystyrene particles by neutrophils (with a maximum enhancement by 180% for neutrophils of the patients with decreased immuno-status) and monocytes (with a maximum of 89% for monocytes of healthy donors). Cp enhances phagocytosis of neutrophils and monocytes by binding these cells, not by opsonizing ingested particles as a conventional opsonin (ie. lipopolysaccharide from E.coli). The stimulating effect of Cp on phagocytosis was three times higher than that of LPS from E.coli.

Candida albicans↗

PubMed1991

[Protective effect of various forms of human ceruloplasmin in copper-induced erythrocyte lysis].

It is known that human ceruloplasmin (CP) is made up of several isoforms which differ by the structure of their carbohydrate fragment. One of these isoforms, CP1, which makes up to approximately 40% of the native CP molecule and which contains a carbohydrate fragment, [formula: see text] is specifically bound to human erythrocyte (ER) receptors. This isoform was isolated by using lectin affinity chromatography. It was found that CP1 produces a much stronger protective effect on ER during Cu(2+)-induced lysis as compared with CP. A kinetic analysis of Cu2+ accumulation and reduced glutathione (GSH) decline in ER revealed that the lack of correlation between these two processes. It was found that in the presence of CP and CP1 the GSH concentration is not critical for the hemolytic resistance of ER. In the presence of CP1 ER hemolysis occurs at a slower rate whereas the GSH decline at a much faster rate than in the presence of CP.

Ceruloplasmin↗

PubMed1991

[Interconnection between the structure and protective action of normal and pathological ceruloplasmin preparations in copper-induced erythrocyte lysis].

It was found that the differences in the protective effects of ceruloplasmin (CP) isolated from the blood of healthy donors and of the ceruloplasmin-like protein (pat-CP) isolated from the blood of patients with hepatovertebral dystrophy (HCD) during Ca(2+)-induced lysis of erythrocytes (RBC) result from significant changes in the carbohydrate fragment of pat-CP, the bulk of which (65%) is devoid of mannose and acetylglucosamine residues. According to the data from lentil-lectin Sepharose chromatography, only 4% of pat-CP molecules contain the [formula; see text] fragment necessary for the binding to ER receptors. The curves reflecting the Cu2+ accumulation in healthy donor ER and in pat-CP during the Cu(2+)-induced lysis were found to differ significantly. The ability of pat-CP to prevent the accumulation of Cu2+ in ER and pat-ER was markedly decreased compared with CP. Besides, CP prevented the diminution of reduced glutathione (GSH) in ER in a greater degree than pat-CP, whereas pat-ER, in contrast with CP, had no effect on the GSH concentration in pat-ER. It is suggested that the reactions occurring in the cell during Cu(2+)-induced lysis of ER and pat-ER are different.

Ceruloplasmin↗

PubMed1991

[Immunoenzyme determination of the total level of ceruloplasmin in the serum from patients with hepatocerebral dystrophy].

An immunoenzymatic method for ceruloplasmin analysis (IEA) based on the use of horseradish peroxidase-labelled monospecific antibodies as markers has been developed. IEA can be used for direct measurements of ceruloplasmin in blood serum, as can be evidenced from the coincidence of calibration plots obtained after the use of potassium-phosphate buffer and ceruloplasmin-free sera. The procedure allows the determination of the total content of ceruloplasmin present in the blood sera of patients with hepatocerebral dystrophies both in the active and inactive forms. The minimum ceruloplasmin concentration detectable by this method is 5 x 10(-9) g/ml. The method was used to determine ceruloplasmin levels in the blood of patients with various grades of hepatocerebral dystrophy. Analysis of blood sera from 6 patients revealed that the ceruloplasmin concentrations determined by IEA were very close, whereas the oxidase activities of this protein differed more than 7-fold. The amount of enzymatically active ceruloplasmin as determined from the oxidase activity made up to 10-68% of the total ceruloplasmin content in the sera, depending of the severity of the pathology.

Antibodies, Monoclonal↗

PubMed1991

Immunoenzyme determination of total serum ceruloplasmin. Application to Wilson disease.

Enzyme immunoassay for ceruloplasmin (CP)*, employing monospecific CP antibodies labeled with horse radish peroxidase was developed. This method permits to determine total content of CP, which is present in Wilson disease patients' blood in enzymatically active and enzymatically inactive forms. The evidence is presented that the method can be used for a direct determination of CP in blood serum. The minimal CP concentration which may be determined by enzyme immunoassay (IEA) is 5.10(-9) g/ml. The method was used for determination of CP concentrations in Wilson disease patients' blood with different disease severity. Analysis of blood samples taken from 6 Wilson disease patients with the use of IEA method revealed similar total CP concentrations. At the same time, the oxidase activities of CP in the blood of different patients varied more than sevenfold.

Antibodies↗

PubMed1990

Interrelation between structure and protective action of normal and pathological ceruloplasmins during copper-induced lysis of red blood cells.

The origin of the difference between the protective action of ceruloplasmin (CP) from healthy donors blood and of ceruloplasmin-like protein (p-CP) from blood of patients with Wilson disease which they exert during copper-induced lysis of red blood cells (RBC) was elucidated. The difference is due to a significant change in the carbohydrate moiety of p-CP the major proportion of which (65%) does not contain mannose and acetylglucosamine residues. The data of chromatography on lentil lectin reveal that only 4% of p-CP molecules contain the fragment [table: see text] required for binding to RBC receptors. It was shown that the time-courses of copper accumulation in RBC of normal donors and in RBC of patients with Wilson disease (p-RBC) during copper-induced lysis differ markedly from each other. The p-CP is able to prevent copper accumulation in RBC and p-RBC to a significantly less degree than CP. It was also established that CP prevents the decrease of reduced glutathione (GSH) level in RBC to a greater extent than p-CP. In contrast to CP, the p-CP exerts no effect on the decrease in GSH concentration in p-RBC. These results may indicate that no interaction between Cu2+ and reduced glutathione takes place in p-RBC, in contrast to the situation occurring in normal RBC.

Ceruloplasmin↗

PubMed1990

Protective action of blood ceruloplasmin obtained from normal individuals on red blood cells compared with that from patients with Wilson's disease.

A ceruloplasmin-like protein (pathological CP, p-CP) was isolated from the serum of patients with Wilson's disease whose antigenic determinant was identical to that of ceruloplasmin (CP) obtained from the blood of normal individuals. Because the protective action of CP involves its interaction with receptors on red blood cells (RBC), the binding of CP and p-CP to the RBC from normal individuals and to those from patients with Wilson's disease (p-RBC) was investigated. The number of binding sites for CP on both types of RBC was significantly lower than that for p-CP. The dissociation constants for CP-RBC and CP-p-RBC complexes were very similar (1.15 and 1.37 nM, respectively), as were those for the complexes of p-CP with RBC and p-RBC (11.1 and 11.8 nM, respectively), but the binding constants for p-CP with RBC of both types were ten times higher than the CP binding constants. The ability of CP to prevent Cu(2+)-induced lysis of RBC was significantly higher than that of p-CP. The protective action of CP and p-CP during RBC lysis in two Fe(2+)-containing systems did not correlate with their oxidative and ferroxidase activities. On the contrary, the protective effect of p-CP, which had significantly lower oxidase activity and no ferroxidase activity, was greater than that of CP.

Ceruloplasmin↗

PubMed1990

[Protective effect of ceruloplasmin during human erythrocyte lysis induced by Fe2+ ions].

In order to elucidate the nature of linkage between the oxidase activity and protective effect of ceruloplasmin during the Fe2(+)-induced lysis of erythrocytes, the both factors were identified in ceruloplasmin samples prepared from blood sera of healthy donors and patients with hepatocerebral dystrophy (HCD). It was found that the oxidase activity of healthy donor ceruloplasmin markedly exceeds that of HCD patients, whereas the protective effect of the HCD protein, contrariwise, markedly exceeds that of normal ceruloplasmin. The data obtained suggest that the protective effect of ceruloplasmin during Fe2(+)-induced erythrocyte lysis is not correlated with its oxidase (ferroxidase, in particular) activity.

Brain Diseases↗

PubMed1990

Studies on receptor interaction of ceruloplasmin with human red blood cells.

The interaction of CP with the red blood cell (RBC) receptor was shown to be a Ca2+ dependent process and be limited by CP binding on RBC membrane which is not followed by CP transport through the membrane into RBC. The nature of receptor interaction was determined. It was shown that receptors are formed by glycoproteins of PAS1 and PAS2 (glycoforin dimer and monomer, respectively) and terminal residues of sialic acid of these glycoproteins are important for CP reception. Receptor carbohydrate specificity was determined. Biantennary structure of CP molecule carbohydrate moiety which is bound to the receptor owing to 2 structural fragments: sialic acid terminal residues and the fragment including acetylglucosamine dimer and fucose, plays the main role in CP reception.

Biological Transport↗

PubMed1990

The protective effect of normal and pathological (Wilson disease) ceruloplasmins on human erythrocytes.

The binding of the ceruloplasmin (CP) from the healthy donor blood and of ceruloplasmin-like protein (p-CP) isolated from the Wilson patients' blood with erythrocytes (RBC) of healthy donors and with RBC of Wilson's patients (p-RBC) was investigated. It was shown, that the number of CP binding sites both on the RBC and p-RBC was significantly lower than that for p-CP, but Kd value for p-CP binding with both types of erythrocytes was approximately ten times higher than Kd value for CP. The protective action of CP on copper stimulated hemolysis is significantly higher than that of p-CP. The protective action of CP on ferrous ion stimulated hemolysis does not correlate with its ferroxidase activity. Contrariwise, the protective effect of p-CP which has no ferroxidase activity is more powerful than that of CP.

Ceruloplasmin↗

PubMed1990

[Comparison of the protective effects on the erythrocytes of ceruloplasmin from the blood of healthy donors and patients with hepatocerebral dystrophy].

The binding of the ceruloplasmin (CP) from the healthy donor's blood and of ceruloplasmin--like protein (p-CP) isolated from the Wilson disease patient's blood with erythrocytes (RBC) of healthy donors and with RBC of Wilson's patients (p-RBC) was investigated. It was shown, that the CP number of binding sites both on the RBC and p-RBC was significantly lower than that for p-CP, but Kd value for p-CP binding of the both types of erythrocytes was approximately 10 times higher than Kd value for CP. The protective action of CP on copper stimulated hemolysis is almost 3 times higher than that of p-CP. The protective action of CP on ferrous ion stimulated hemolysis doesn't correlate with its ferroxidase activity. On the contrary the protective effect of p-CP which has no ferroxidase activity is more powerful than that of CP.

Binding Sites↗

PubMed1990

The protective effect of different forms of human ceruloplasmin in copper-induced lysis of red blood cells.

The comparison of protective effects of native ceruloplasmin (CP) and of preparation CP1 containing carbohydrate fragment GlcNAc(beta(1,4]GlcNAc which specifically binds on RBC (alpha(1,6)Fuc receptors showed that CP1 exhibits much more powerful protective effect on RBC in copper-induced lysis. It was found, however, that CP2 (native CP devoided of CP1) protected RBC as well as CP despite its inability of binding to RBC membrane. CP and CP1 in a similar way decrease copper concentration in RBC. It was shown that copper accumulation and GSH decrease in RBC are two independent and concurrent processes; the copper and GSH concentrations are not the factors determining RBC resistance to hemolysis. CP inhibits the reaction of superoxide radicals generation as a result of Cu interaction with -SH groups of RBC membrane; the effect is more pronounced than the effect of catalase or superoxide dismutase. CP and CP1 preparations equally inhibit this reaction. Apparently CP reception on RBC leads not only to membrane protection from superoxide and hydroxyl radicals but represents a more complex process.

Carbohydrate Sequence↗

PubMed1990

Study of ceruloplasmin oxidase activity. The effect of pH.

To find out the mechanism of ceruloplasmin (CP) oxidase activity CP interaction with organic substrates adrenaline (AD), catechol, p-phenylenediamine) and Fe2+ was investigated. CP was shown to interact with the above substrates according to the Theorell-Chance mechanism to form a kinetically insignificant ternary complex. The oxygen molecule binds first to CP followed by the molecule of electron donor: the inhibition of enzymatic oxidation by the reaction product is competitive. The effects of pH on kinetic parameters (Ksm, Vs) of oxidation reactions of AD and Fe2+ in the presence of CP were examined. AD was shown to be able to bind both to the protonated and to the non-protonated form of CP whereas Fe2+ interacts only with the protonated form: the rate of catalytic event (Vs) is influenced by pH in the presence of AD whereas in the presence of Fe2+ only binding to CP (Ksm) is affected by pH. Kinetic schemes describing the order of binding of hydrogen ions in the course of above reactions are proposed.

Binding, Competitive↗

PubMed1989

[Protective effect rendered by human ceruloplasmin on erythrocytes in hepatocerebral dystrophy].

In order to elucidate the protective effect of human ceruloplasmin (CP) on erythrocytes in patients with hepatocerebral dystrophy (HCD), the parameters reflecting the interaction of CP from the blood of healthy donors (n-CP) and of HCD patients (h-CP) with erythrocytes from healthy donors (n-ER) and from HCD patients (h-ER) were estimated. The protective effects of n-CP and h-CP on n-ER and h-ER during the Cu2+-induced lysis were compared. It was shown that the ability of h-CP to prevent the human ER breakdown upon Cu2+-induced lysis is much lower (approximately 3-fold) than that of n-CP. The differences in the protective effect of n-CP and h-CP are manifested in a greater degree during the n-ER lysis than during the h-ER lysis.

Ceruloplasmin↗

PubMed1988

[Characteristics of ceruloplasmin interaction with a specific receptor of human erythrocytes].

The equilibrium binding of ([125I]ceruloplasmin) ([125I]CP) to a specific receptor of human erythrocytes was investigated. It was shown that reaching the binding equilibrium is a slow process. A strong dependence of binding on Ca2+ concentration (from 0.1 to 1 mM) was revealed; the optimal values were achieved at millimolar concentrations of Ca2+.Mg2+ do not affect the binding of [125I]CP. Under conditions of optimal binding (0.01 M Tris-HCl buffer pH 7.4 containing 158 mM NaCl and 1 mM Ca2+, 4 degrees C), the values of constants for [125I]CP binding to intact erythrocytes (Kd = 1.0 nm) and to membrane fragments (Kd = 0.8 nM) as well as the number of binding sites (16.3 X 10(-15) mol per 40,000,000 erythrocytes) were determined. No ceruloplasmin transport across the erythrocyte membrane was observed. This finding and the similarity of Kd values for ceruloplasmin binding to membrane fragments and to intact erythrocytes indicate that the effect of ceruloplasmin on human erythrocytes is due to the protein molecule interaction with membrane receptors.

Biological Transport↗

PubMed1988

[Ceruloplasmin receptor on human erythrocytes].

The structural fragments of the human ceruloplasmin (CP) molecule and of erythrocyte receptors which provide for the specific interaction of CP with erythrocytes were identified, and their properties were investigated. The interaction of CP with erythrocytes, both intact and treated with neuroaminidase and proteolytic enzymes (trypsin, chymotrypsin, papaine, pronase E) is described. Experiments with CP reception were performed at 4 degrees C, using [125I]CP and [125I]asialo-CP. The parameters of binding were determined in Scatchard plots. It was demonstrated that the specific binding of CP to erythrocyte receptors is determined by its interaction with two structural sites of the carbohydrate moiety of the CP molecule, i.e., the terminal residues of sialic acids and a site, (formula; see text) located at a large distance from the chain terminus.

Binding, Competitive↗

PubMed1987

[Pre-steady state kinetics of the ferroxidase reaction catalyzed by ceruloplasmin].

Analysis of the presteady-state step of the ferroxidase reaction catalyzed by ceruloplasmin revealed that the kinetic curve for the reaction product accumulation versus time is characterized by an induction period, tau, whose value does not change within the pH range of 5.0-7.5. The value of tau decreases with a rise in the enzyme concentration and increases with a rise in the substrate concentration at constant Fe(II) and E0 concentrations. A reaction scheme is proposed which points to the existence of an induction period in the ceruloplasmin-catalyzed ferroxidase reaction. It was shown that the calculated values of tau = f([Fe(II)]0) and tau = f([E]0) obtained through the use of differential equations qualitatively coincide with the corresponding experimental values.

Ceruloplasmin↗

PubMed1986

[Kinetic study of the oxidase reaction of ceruloplasmin].

The effects of ionic strength, buffer composition and pH on the oxidase activity of ceruloplasmin isolated from human donor blood were studied. The steady-state kinetics of ceruloplasmin-catalyzed oxidation of organic substrates (pyrocatechine, adrenaline, rho-phenyldiamine) and Fe(II) was analyzed. The relationship between the initial reaction rate and Fe(II) concentration is described by the Michaelis--Menten kinetics, that for organic substrates--by substrate activation or by a scheme which implicates the existence of two catalytic centers in the enzyme molecule. The inhibition of adrenaline oxidation by its reaction product, adrenochrome, is competitive. The reactions studied were shown to occur via the formation of a ternary complex.

Catalysis↗