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Biomedical subjects

A Z Budzynski

Publications and source records attributed to A Z Budzynski.

At least 73 records · Page 4Linked to original sources
PubMed1979

Primary soluble plasmic degradation product of human cross-linked fibrin. Isolation and stoichiometry of the (DD)E complex.

The formation of the (DD)E complex and fragments DD and E upon proteolysis of human cross-linked fibrin was studied by timed digestions using varying amounts of plasmin. The (DD)E complex was the primary soluble degradation product released form cross-linked fibrin. This complex contained fragments DD and E1. Upon further digestion (DD)E1 complex was cleaved to (DD)E2 complex whereby only the fragment E moiety was affected. However, when fragment E2 was digested to fragment E3, dissociation of the complex occurred. Thus, fragments DD and E3 are the terminal plasmic digestion products of cross-linked fibrin. This pattern was consistent regardless of the plasmin to fibrin ratio; however, the rate of production of the terminal degradation products was directly dependent upon enzyme concentration. Digestion conditions were modified so that either the (DD)E complex or fragment DD was the predominant degradation product, allowing for the purification of these species by one-step gel filtration. The molar ratio of fragment DD to fragment E in the (DD)E complex was investigated by dissociation of the complex and by reassociation of the purified components. The (DD)E complex contains one molecule of fragment DD and one molecule of fragment E.

Chemical Phenomena↗
PubMed1979

Modification of high molecular weight plasmic degradation products of human crosslinked fibrin.

The predominant high molecular weight products of plasmic digestion of human crosslinked fibrin Fragments DD, E and (DD)E complex were purified by column gel filtration in a non-dissociating buffer or by ion-exchange chromatography on DEAE-cellulose. The structure of the degradation products was studied by proteolytic degradation, polyacrylamide gel electrophoresis immunodiffusion and sucrose density gradient centrifugation. Unaltered derivatives were very resistant to proteolytic degradation by plasmin. In the the presence of 10 mM EDTA the (DD)E complex did not dissociate, but similar to Fragment DD, became susceptible to plasmic degradation forming Fragment D derivatives. The (DD)E complex dissociated in 3 M urea at pH 5.5, had an altered conformation as evidenced by its aggregability and by its increased susceptibility to degradation by plasmin resulting in the formation of Fragment d. The gammagamma chain remnants of Fragment DD were attacked first, followed by cleavage of the beta chain remnants. It is concluded that plasmin resistance is a function of the intact structure and it is not directly dependent on the presence of the crosslink bonds or calcium ions.

Fibrin↗
PubMed1977

Degradation pathway of fibrinogen by plasmin.

The molecular weights of derivatives obtained from chemical and enzymatic degradation of fibrinogen and fibrin support a model in which the two halves of the fibrinogen molecule are covalently linked by a set of disulfide bonds at the amino-terminal region. The 2 asymmetric cleavages caused by plasmin in the fibrinogen molecule occur according to the reactions: X leads to Y + D Y leads to E + D. The quantitative analysis of the amino-terminal amino acids in fragments D (from fibrinogen) and DD (from crosslinked fibrin) yields a total of 3.0 and 6.9 moles of amino acids per mole of protein, indicating three and six polypeptide chain structures, respectively. The data on molecular weights, polypeptide chain composition and immunologic properties of fibrinogen degradation products support the hypothesis on the asymmetric pathway of fibrinogen degradation by plasmin and the formation of two fragment D and one fragment E molecules from each molecule of fibrinogen.

Chemical Phenomena↗
PubMed1977

The half-life of plasmic degradation products of human fibrinogen in rabbits.

Human fibrinogen and purified plasmic degradation fragments X (stages 1 and 2), D and E were labelled with 125-I using the lactoperoxidase method. The chromatographic, electrophoretic and immunologic properties of the labelled proteins were found to be similar to those of non-labelled fragments. All the degradation products diffused rapidly (T 1/2 0.27-0.75 hours) from the intravascular space of rabbits, as compared with fibrinogen (4.26 hours). In addition, the metabolic half-life was found to be 49.3 hours for fibrinogen, as compared with only 5.6, 6.1, 2.3 and 1.4 for fragments X (stage 1), X (stage 2), D and E, respectively. The metabolic half-life roughly reflects the molecular size of the degradation products.

Animals↗
PubMed1977

Quantitative venographic assessment of deep vein thrombosis in the evaluation of streptokinase and heparin therapy.

A technique of quantitative venography has been developed in which values are assigned to the deep veins of the calf, knee, thigh, and pelvis, based upon the calculated volume and degree of occlusion of these venous segments. A maximum score of 40 units reflects complete thrombosis of all segments. This technique has been applied to a randomized, single-blind study of streptokinase versus heparin treatment. Each group of 12 patients had similar mean inital venographic scores; follow-up venograms were performed 5 days after the start of therapy. Streptokinase patients with high initial scores (larger than 20) showed a mean improvement of 12.1 units, while those with low initial scores(less than 20) were essentially unchanged. Heparin patients with high scores had a minimal mean improvement of 1.1 units, but those with low scores had a significant mean extension of thrombosis of 8.6 units. Patients with symptoms for less than 7 days showed greated mean improvement (12.7 units) with streptokinase that those with a longer duration of symptoms (2.0 units); heparin patients in these subgroups showed a mean worsening of 7.5 units and no change, respectively. Extrinsic venous obstruction by tumor did not prevent an excellent response to streptokinase. No single test of coagulation of fibriolysis was a reliable indicator of the degree of venographic response to lytic therapy. Pyrexia and hemorrhagic complications occurred in over one-half of the streptokinase patients; one had an anaphylactic reaction, and one died of intracerebral hemorrhage during therapy. The data suggest that lytic therapy is best restricted to the patient with acute extensive thrombosis. Also, continuous infusions of heparin according to current guidelines may be inadequate to prevent thrombus growth in some patients.

Adolescent↗
PubMed1977

Significance of the intact polypeptide chains of human fibrinogen in ADP-induced platelet aggregation.

The presence of human fibrinogen in suspensions of washed human platelets is a requirement for ADP-induced platelet aggregation. Digestion of fibrinogen with plasmin destroys this function of the protein. The high solubility fraction of Kabi fibrinogen, fragment X (stage 1) and framgent X (stage 2), are two, eight, and ten times, respectively, less potent in promoting ADP-induced platelet aggregation, as compared with intact fibrinogen. Fragments Y and D and the mixture of reduced and carboxymethylated chains of human fibrinogen do not support ADP-induced platelet aggregation at all. SDS polyacrylamide gel electrophoresis of nonreduced and reduced fibrinogen and its derivatives indicates that the intact fibrinogen molecule is essential for ADP-induced platelet aggregation. It is suggested that the carboxy-terminal part of the Aalpha chain and possibly also the amino-terminal part of the Bbeta chain are required for the platelet aggregation-promoting function of fibrinogen.

Adenosine Diphosphate↗
PubMed1976

Comparison of the physicochemical properties of fragment D derivatives of fibrinogen and fragment D-D of cross-linked fibrin.

The molecular weight of Fragment D derivatives obtained from plasmic digests of fibrinogen and cross-linked fibrin was determined by equilibrium sedimentation and compared with the summated molecular weight of their polypeptide chains observed after electrophoresis of reduced protein in sodium dodecyl sulfate polyacrylamide gels. The measured molecular weight of Fragment D (Stage 2) of fibrinogen is 103 500, which is compatible with a molecule containing only one each of the Aalpha (13 000), Bbeta (43 000) and gamma (39 000) chain remnants. Fragment D-D of cross-linked fibrin has a molecular weight of 189 000, compatible with a molecule containing one isopeptide-bound gamma-gamma chain (80 000) and two each of Bbeta (43 000) and Aalpha (13 000) chain remnants. The NH2-terminal amino acid residues of the Fragment D derivatives were measured quantitatively using a thioacetic-thioglycolic acid method, and molar quantities were calculated on the basis of the molecular weights determined by equilibrium sedimentation. Fragment D preparations obtained from Stage 2 and Stage 3 digests of fibrinogen have 3 mol of NH2-terminal amino acids per molecule, while Fragment D-D has seven. These data support the view that two Fragment D molecules, each of three polypeptide chains, are derived by plasmic degradation from each fibrinogen molecule, and that an isopeptide-bound, six chain Fragment D-D molecule is released from cross-linked fibrin by plasmin. Equlibrium sedimentation measurement of the molecular weights of Fragment X (Stage 1 and Stage 2) and Fragment Y are 265 000 and 148 000, respectively. These values are compatible with asymmetric cleavages of Fragment X to Fragments Y and D (Stage 2), and of Fragment Y to Fragments D (Stage 2) and E, and with a fibrinogen model in which the two halves are joined by disulfide bonds only in the amino-terminal regions.

Electrophoresis, Polyacrylamide Gel↗
PubMed1976

Plasmic degradation of fibrinogen Paris I.

Fibrin obtained from the plasma of a patient having abnormal fibrogen Paris I contains normal alpha, beta, and gamma polypeptide chains as well as an abnormal gamma-chain (gammaParis I) of approximately 51,000 daltons molecular weight. Plasmic digestion of Paris I fibrogen and noncrosslinked fibrin yields both normal and abnormal Fragment D molecules, the latter having a higher negative charge and molecular weight than that liberated from normal fibrinogen and noncorsslinked fibrin. After disulfide bond reduction, an abnormal polypeptide chain of approximately 40,500 +/- 2,000 daltons molecular weight was demonstrated in the Paris I digests by dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Comparison with the electrophoretic pattern for reduced digests of normal substrates indicates that it is a gamma-chain remnant in the normal Fragment D. Although the carbohydrate content in the gamma-Paris I-chain is slightly higher than that in the normal gamma-chain, as measured by periodic acid-Schiff reagent (PAS) staining intensity, it is concluded that extra carbohydrate does not account for the high molecular weight of the gamma-Paris I-chain since the 40,500 dalton chain does not stain with PAS. Plasma digestion of Paris I crosslinked fibrin yields a large amount of Fragment D in addition to Fragment D-D ("D-dimer") and E molecules, in contrast to a digest of normal crosslinked fibrin, from which only the latter two fragments are formed. This finding suggests that the defect in fibrinogen Paris I derives from an abnormality in the carboxy-terminal region of the gammaParis I-chain, so that in the presence of Factor XIII, these chains are not crosslinked and Fragment D-D molecules are not liberated upon subsequent plasmic degradation. The data provide support for the previous conclusion that a longer than normal polypeptide chain sequence at the carboxy-terminal portion of the gammaParis I-chains accounts for the increased size of these chains relative to the normal gamma-chains and for the abnormal function of the intact fibrinogen Paris I molecule.

Blood Protein Electrophoresis↗
PubMed1975

Determination of human fibrinopeptide A by radioimmunoassay in purified systems and in the blood.

The formation of fibrin clots or circulating soluble fibrin is accompanied by the appearance of fibrinopeptides. Measurement of the fibrinopeptide concentration in plasma can provide important information on the rate of conversion of fibrinogen to fibrin by thrombin. This rate varies under different physiologic and pathologic conditions. Fibrinopeptide A is a better molecular marker of the conversion than fibrinopeptide B since it is the first peptide to be cleaved by thrombin. A radioimmunoassay technique has been developed for the quantitative determination of human fibrinopeptide A. The procedure detects human fibrinopeptide A at a concentration of approximately 0.05 ng/ml. The variation of fibrinopeptide A content in normal persons may reflect its rapid formation and catabolism. A significantly increased concentration of this peptide was found in a patient during defibrination therapy with a purified enzyme from the venom of Agkistrodon rhodostoma and in patients suffering from retinal vascular occlusions.

Amino Acid Sequence↗
PubMed1975

Electron microscopic studies of plasmic degradation products of fibrinogen. Implications for the disulfide structure of fibrinogen.

Fibrinogen, coagulable plasmic derivatives (Fragments X) and Fragments Y, D and E were studied by negative staining electron microscopy. Fragment X obtained from Stage 1 digests and fibrinogen were both globular, while Fragment X of Stage 2 digests appeared as a nodular filament. The Stage 1 and Stage 2 Fragment X preparations had approximately the same molecular weight, but could be differentiated by several subtle differences in polypeptide chain structure. Fragments Y and D were also filamentous, although shorter than Fragment X (Stage 2), and Fragment E appeared as a small, compact or folded filament. These results agree with the concept that fibrinogen consists of a strand of nodules connected by thin strands, folded into a compact, spherical shape. The molecule opens up when stabilizing bonds are disrupted or liberated by plasmin. The data are compatible with a fibrinogen molecule in which the two halves are linked by a single locus of disulfide bonds at the amino terminus and with the asymmetric hypothesis of plasmic degradation to Fragments X, Y, D and E.

Binding Sites↗