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Biomedical subjects

C S Cierniewski

Publications and source records attributed to C S Cierniewski.

At least 109 records · Page 6Linked to original sources
PubMed1983

Interaction of fibrinogen with mercury.

The interaction of bovine fibrinogen with mercuric chloride was studied. Gel filtration on Sephadex G-25 revealed that fibrinogen bound twice the amount of mercury such as fibrin or fibrin monomers (8.8, 4.5, and 3.4 micrograms Hg2+ ions/mg protein, respectively). Fibrinogen complexed with mercury or in the presence of Hg2+ ions at concentration above 10-6 M was clotted by thrombin more effectively than in the control system which was devoid of this metal. Reaggregation of the purified fibrin monomers was not affected by mercury.

Animals↗
PubMed1983

Fluorescence studies of the blood platelet membranes associated with fibrinogen.

To follow microviscosity changes in membranes associated with fibrinogen binding to human platelets, specific fluorescent probes were used and their fluorescence anisotropy was analysed. The degree of fluorescence anisotropy of diphenylhexatriene, anilinonaphthalene sulfonate (ANS) and fluorescamine increased significantly when fibrinogen reacted with its membrane receptors. Fluorescence polarization analyses showed that fibrinogen binding to platelet membranes is accompanied by an increase in the membrane lipid rigidity. On the other hand, changes in the fluorescence anisotropy of membrane tryptophans and N-(3-pyrene)maleimide suggest augmented mobility of the membrane proteins. The binding of fibrinogen to the membrane receptors is not accompanied by any change in the fluorescence intensity of ANS attached to the membranes. This may suggest that covering of platelets with fibrinogen molecules does not influence the surface membrane charge.

Blood Platelets↗
PubMed1983

Microenvironment changes of human blood platelet membranes associated with fibrinogen binding.

Alterations in the membrane organization caused by fibrinogen binding to human blood platelets and their isolated membranes were analyzed by fluorescence and electron spin resonance measurements. The degree of fluorescent anisotropy of DPH, ANS and fluorescamine increased significantly when fibrinogen reacted with its membrane receptors. Both fluorescence and ESR analyses showed that fibrinogen binding to platelet membranes is accompanied by an increase of the membrane lipid rigidity. This effect seems to be indirect in nature and is mediated by altered membrane protein interactions. As it has been shown that an increased membrane lipid rigidity leads to a greater exposure of membrane proteins, including fibrinogen receptors, this might facilitate a formation of molecular linkages between neighboring platelets. On the other hand, changes of fluorescence anisotropy of membrane tryptophans and N-(3-pyrene) maleimide suggest the augmented mobility of the membrane proteins. Evidence is presented which indicated that the binding of fibrinogen to the membrane receptors is not accompanied by any changes in the fluorescence intensity of ANS attached to the membranes. It may suggest that the covering of platelets with fibrinogen does not influence the surface membrane charge. In contrast to fibrinogen, calcium ions caused an increase of the fluorescence intensity resulting from the more efficient binding of ANS to the platelet membranes.

Adenosine Diphosphate↗
PubMed1983

Effect of heavy metals and alkali metals on L-leucine uptake by human blood platelets.

The transport of L-leucine into human blood platelets was characterized as a function of time and amino acid concentration in the medium. Inhibition analyses showed that L-leucine uptake can be only partially inhibited by other amino acids including those which are believed to be transported by the same L system. When Cu2+, Zn2+, Mg2+, Co2+, Fe2+, Ba2+, or Cd2+ were introduced into the transport medium to the final concentrations of 2.5 and 5.0 mM, they inhibited significantly the L-leucine uptake into platelets. In contrast, the initial rate of L-leucine uptake was enhanced by Cu+ ions. Ceruloplasmin, a copper transporting protein, caused almost a complete inhibition of L-leucine uptake.

Adult↗
PubMed1983

Alteration of the antigenic structure of human fibronectin caused by complexing with collagen.

The complex formation between fibronectin and denatured collagen is associated with a significant decrease of antigenic expression of the fibronectin epitopes. This conclusion is evidenced by critical changes in the value of competitive inhibition parameters such as CImax. Generally, an alteration of the fibronectin antigenic structure is similar to that observed after thermic denaturation of the molecule.

Collagen↗
PubMed1982

Inhibitory effect of fibronectin on the fibrin formation.

125I-fibronectin is incorporated into fibrin when blood plasma is clotted with thrombin. This process is dependent upon fibronectin concentration, temperature, and the presence of calcium ions. Fibronectin appears to be a very strong inhibitor of fibrin formation and influences both the thrombin clotting time and fibrin quality.

Binding, Competitive↗
PubMed1982

The intrinsic fluorescence of human fibrinogen and its fragments D and E.

The tryptophan fluorescence of fibrinogen and its final degradation products--fragment D and E--were compared. Fibrinogen and its derivatives exhibit identical emission and excitation spectra. Their fluorescence intensity is influenced to a different extent by pH titration and temperature. Our studies showed that tryptophan residues of core fragments D and E are much more exposed to quenching effects of acrylamide and ions than intact fibrinogen, which may be caused by conformational changes occurring over the domains during plasmin digestion of fibrinogen molecule.

Fibrin Fibrinogen Degradation Products↗
PubMed1982

Reactivity of fibrinogen derivatives with antisera to human fibrin D-dimer and its gamma-gamma chain remnant.

Highly purified D-dimer was obtained from plasmin digest of human cross-linked fibrin. After reduction of its disulfide bonds, the gamma-gamma chain remnant, containing cross-linking site, was then isolated by ion-exchange chromatography on CM-cellulose. Antisera obtained by immunizing rabbits with D-dimer and its gamma-gamma chain remnant contained a small population of antibodies which specifically reacted with D-dimer. Thus, a specific radioimmunoassay system allowing detection and quantitation of D-dimer in the presence of fibrinogen and monomeric fragment D was made possible.

Animals↗
PubMed1982

Binding of fibrinogen molecules to pig platelets and their membranes.

Following addition of ADP, 125I-labelled fibrinogen binds specifically to pig platelets. This binding is completely inhibited by the unlabelled fibrinogen. Quantitative analysis indicates the presence of 12,400-25,000 molecules of fibrinogen which can be bound with an association constant of 5 . 10(8) M-1 to platelets. Fibrinogen receptors were found to be active in the isolated platelet membranes as well. Quantitative analysis of the saturable binding of fibrinogen to the platelet membranes showed that these receptors react with the same affinity with fibrinogen molecules. In contrast to the intact platelets, the platelet membranes can specifically bind fibrinogen in the absence of ADP. We conclude that a specific receptor for fibrinogen is exposed on the surface as a result of cell damage which is the first step of the platelet membrane isolation.

Adenosine Diphosphate↗
PubMed1981

Common antigenic sites in human, bovine and porcine fibrinogens.

Specific antisera to the A alpha, B beta and gamma chains of porcine fibrinogen were used to characterize an antigenic homology of human, bovine, and porcine fibrinogens. Antigenic determinants shared by these fibrinogens were mostly formed by the A alpha chain. However, in the case of bovine and porcine fibrinogens they were also found in the B beta and gamma polypeptide chains. The results reported here show that the A alpha chain determinants exposed on the intact fibrinogen molecule are conserved to a considerably larger extent than those of the B beta and gamma chains.

Animals↗
PubMed1980

Chemical structure and properties of duck and goose fibrinogen.

Duck and goose fibrinogen were isolated from fresh pooled plasma by three different methods. To minimize proteolytic activity, epsilon-aminocaproic acid and trasylol were used throughout the preparation procedures. Amino acid composition of fibrinogens and carbohydrate content (hexose, hexosamine, sialic acid) as well as phosphorus were analysed. Intact preparations showed single band on SDS-polyacrylamide gel electrophoresis. After reduction and modification of the thiol groups, the material could be separated by SDS-polyacrylamide gel electrophoresis into four bands corresponding to the gamma, partially degraded A alpha, B beta and intact A alpha chain. Intact polypeptide subunits were separated by ion-exchange chromatography or preparative SDS-polyacrylamide gel electrophoresis and their amino acid compositions were determined. Evidences supporting the view that bird fibrinogen is very sensitive to proteolytic degradation and that a partial degradation of the A alpha chain takes place even when inhibitors are used in all steps of the purification procedures are presented.

Amino Acids↗
PubMed1980

Immunological properties of low molecular-weight proteins binding heavy metals in rat kidney and liver.

Two homogenous fractions of hepatic metallothioneins ((Cd,Zn) MT-1 and (Cd,Zn) MT-2) and renal metal binding proteins ((Bi,Cu) BP-1 and (Bi,Cu) BP-2) were isolated from rats exposed to heavy metals and specific antisera to them were produced in rabbits. These antisera were tested by immunodiffusion and immunoelectrophoresis for their ability to bind different fractions of hepatic Cd,Zn-metallothionein and renal (Bi,Cu)-, (Hg,Cu)- and (Cd,Cu)-binding proteins. It was found that anti (Bi,Cu) BP antisera did not cross-react with hepatic (Cd,Zn) MT-1 and (Cd,Zn) MT-2. Strong immunological cross-reactions were detected between anti (Bi,Cu) BP antisera and individual forms of (Cd,Cu)-, (Hg,Cu)- and (Bi,Cu)-binding proteins isolated from rat kidneys.

Animals↗
PubMed1979

Internalization of the amino terminal 1-78 sequence of the gamma chain of native fibrinogen and exposure associated with catabolism and plasmin cleavage.

Specific antibodies of the gamma 1--78 peptide of human fibrinogen were employed in binding assays and in equilibrium competitive inhibition assays to analyze the expression of gamma 1--78 antigenic determinants as an indication of the relative exposure of the gamma 1--78 sequence in the E domain of fibrinogen, high solubility fibrinogen subfractions I-8 and I-9, and plasmic cleavage fragments of fibrinogen and fibrin. A very limited exposure of gamma 1--78 sequences was found to occur concomitant with proteolytic deletions of the major carboxyterminal segment of the A alpha chains in fgI-8, fgI-9. Exposure of gamma 1--78 is not influenced by further proteolysis to fg-X which is associated with B beta 1--43 deletion. Further proteolysis to fg-Y, which is associated with deletion of beta 43--53 and of one of the D domains, is associated with additional exposure of gamma 1--78. This is not significantly influenced by further proteolysis to fg-E with deletion of the second D domain, deletion of A alpha 1--19, and proteolysis at the carboxyterminal aspects of the E domain chains.

Amino Acid Sequence↗