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PubMed1994

Inhibition of neutrophil activation by fibrinogen.

Physiological levels of human fibrinogen markedly inhibited the chemotactic activity of human neutrophils triggered by zymosan-activated serum (ZAS), C5a, or IL-8 in a Boyden chamber assay. Fibrinogen also slightly inhibited the N-formyl-methionyl leucyl-phenylalanine (FMLP)-induced migration of human neutrophils. Albumin was devoid of the inhibitory activities displayed by fibrinogen in this system. The inhibition of chemotaxis by fibrinogen was dose-dependent and saturable. Fibrinogen placed in the upper compartment of the Boyden chamber produced a larger inhibition than that obtained with fibrinogen placed in the lower compartment. Lysine as well as the lysine analog 6-aminohexanoic acid (AHA) decreased the inhibitory capacity of fibrinogen. In contrast, both arginine and glutamine failed to suppress the fibrinogen-mediated inhibition of neutrophil chemotaxis. AHA counteracts the inhibition of ZAS-induced chemotaxis by anti-CD18 monoclonal antibody, suggesting that lysine binding sites are required for integrin function in chemotaxis. Fibrinogen also inhibited, in a dose-dependent manner, the oxygen consumption of neutrophils activated by opsonized zymosan. Taken together, the present results indicate that fibrinogen modulates neutrophil functions and suggest that in addition to its role in blood coagulation, circulating fibrinogen may be involved in regulation of the inflammatory response.

Amino Acids↗
PubMed1982

Antifibrinolytic treatment in subarachnoid haemorrhage: present state.

Two randomised controlled clinical trials in patients with recently ruptured intracranial aneurysms were undertaken using tranexamic acid (AMCA) to prevent early recurrent bleeding. In our accumulated series of 105 patients 53 were given AMCA and 52 were controls. 13% of the AMCA-treated patients and 31% of the controls rebled. In patients treated with AMCA the recurrent bleeding took place later than the rebleeding in the control patients. Vasospasm and delayed cerebral ischaemic deficits were seen more frequently in patients treated with AMCA. Total mortality from rebleeding and cerebral ischaemia was 25% in AMCA-treated patients and 19% in the controls during the six weeks' observation time. Coagulation factors remained unaffected by the drug. Local fibrinolysis in the cerebrospinal fluid decreased after one week in patients treated with AMCA. After two weeks the fibrinolytic activity was similar in AMCA-treated patients and in the controls. After experimental subarachnoid haemorrhage in 90 rabbits, AMCA was found to suppress plasminogen activator activity, mainly in the leptomeninges. This occurred however only during the first few postbleeding days. Antifibrinolytic agents only appear to reduce the risk of recurrent bleeding during the first ten day period after the primary aneurysm rupture. However they also seem to produce delayed cerebral ischaemia in patients with subarachnoid haemorrhage. Synthetic antifibrinolytics evidently shift the incidence of rebleeding curve to the right but these drugs are probably of diminished value in the subsequent weeks of risk.

4-Aminobenzoic Acid↗
PubMed1990

Histologic studies on endometrium of menstruating monkeys wearing IUDs: comparative evaluation of drugs.

A comparative study was performed to evaluate the effects of antifibrinolytic agents; epsilon-aminocaproic acid (EACA) and tranexamic acid (AMCA); anti-inflammatory drugs (indomethacin, ibuprofen, naproxen); and plant extract (root extract of Boerhaavia diffusa) on the endometrial histology of IUD-fitted menstruating monkeys. A high degree of stromal edema, heavy infiltration of inflammatory cells, long, tortuous endometrial glands, and thin-walled empty blood vessels were observed in IUD endometrium. B. diffusa was found most effective in reducing stromal edema, inflammation, and tortuosity of glands, and in increasing the degree of deposition of fibrin and platelets in the vessel lumen. Antifibrinolytic agents caused partial to complete occlusion of the vessel lumen and anti-inflammatory drugs thickened the vessel wall. Indomethacin reduced inflammation effectively. Conclusively, B. diffusa appears to be a potent antifibrinolytic and anti-inflammatory agent and is, thus, recommended for the treatment of IUD menorrhagia.

Animals↗
PubMed2004

A new in vitro assay for human tumor angiogenesis: three-dimensional human tumor angiogenesis assay.

BACKGROUND: A human tissue-based angiogenesis assay is needed to study the biology of angiogenesis in human tumor tissue and to tailor drug selection for patients. METHODS: Fragments of tumor tissue are embedded in fibrin gels containing medium 199, endothelial growth medium, fetal bovine serum, and epsilon-aminocaproic acid. Tumor implants sprout angiogenic vessels that progressively grow into the fibrin matrix. The differential growth pattern of tumor cells and angiogenic vessels in the fibrin gel matrix separates the angiogenic vessels and the tumor stroma into independently observable regions (vessel and tumor compartments). The reproducibility of the assay was tested by using fresh tissue obtained from human tumor xenografts (IMR-32 [neuroblastoma], MDA-MB-231 [breast cancer], and LNCaP [prostate cancer]) grown in nude mice and from fresh surgical breast and thyroid cancer specimens. RESULTS: All tumor fragments studied showed angiogenic sprouting into the fibrin matrix. This created an angiogenic vessel compartment, which was separate from the tumor fragment. The capillary nature of sprouting was confirmed histologically by factor VIII immunohistochemistry. The angiogenic growth fraction was >80% in all groups studied. CONCLUSIONS: This assay may allow functional assessment of the angiogenic potential of human tumors and simultaneous evaluation of a therapeutic agent's antitumor and antiangiogenic effects by virtue of its dual-compartmental structure.

Angiogenesis Inhibitors↗
PubMed1992

Antithrombotic and thrombolytic activity of sulodexide in rats.

We evaluated the ability of sulodexide, an extracted glycosaminoglycan, to prevent thrombus formation and to reduce a stabilized thrombus in a rat venous thrombosis model (vena cava ligature). Injection of sulodexide 10 min before induction of venous stasis, prevented thrombus formation in a dose-dependent manner (median effective dose 0.55 mg/kg). When given to rats with 6-h-old thrombi, sulodexide caused a marked reduction in thrombus size which reached 70% after 2 h with the highest dose tested (2 mg/kg). The effect of sulodexide on established thrombi appears to be due, at least in part, to a fibrinolysis-mediated mechanism, since it was significantly inhibited by epsilon-aminocaproic acid, a well-known antifibrinolytic drug. Treatment with sulodexide did not noticeably affect plasma levels of plasminogen activator and its specific inhibitor. We also showed that fluorescein-labelled sulodexide, when given to animals with 6-h-old thrombi, was present within the thrombi harvested 2 h later, but was then absent from blood. The fluorescence was mainly located in areas filled with amorphous material, that was identified as fibrin by staining with phosphotungstic acid-hematoxylin. No fluorescein-labelled material could be detected in rats treated with fluorescein alone. These findings indicate that, besides preventing venous thrombus formation, sulodexide is able to promote thrombus dissolution by a mechanism that is partly related to local fibrinolysis stimulation.

Animals↗
PubMed1990

Positive influence of nifedipine on early-stage minipig shock lung.

Mechanical and biochemical lesions can be observed in shock lung. To investigate the influence of the calcium antagonist nifedipine on these lesions, we produced shock lung in male minipigs. Three groups (control, thrombin, and thrombin + nifedipine; n = 5) were formed. In the second and third group thrombin was administered intravenously (400 IU/kg body weight) over a period of 2 h. After that the animals received aminocaproic acid (100 mg/kg body weight/h) throughout the rest of the study. Nifedipine was administered in the third group at a dosage of 46 micrograms/kg body weight/h. During the investigation period coagulation and hemodynamic status were examined as well as blood gas levels. Then the isolated lungs were examined. Without nifedipine there was a significant decrease in arterial PO2, an increase in airway opening pressure (Pi), and a decrease in weight-specific end-inspiratory lung compliance (Ci). These changes were not observed under the influence of nifedipine, after which the results were similar to the control group. This demonstrates a positive influence of nifedipine on the acid-base status and the investigated lung mechanical parameters.

Animals↗
PubMed2002

Study on the mechanism of the annexin II-mediated co-assembly of t-PA and plasminogen.

In order to further investigate the effect of annexin II (Ann-II) on tissue plasminogen activator (t-PA)-dependent plasminogen (PLG) activation and its interactive mechanism, recombinant native Ann-II bound t-PA, PLG and plasmin with high affinity was examined. The flow cytometric assay showed that the ann-II expression rate was higher in the human umbilical vein endothelial cell (HUVEC) (87.65%) than in the HL-60 cells as controls (35.79%). Two irrelevant proteins, bovine serum albumin (BSA) and equine IgG (EIG) had no effect on the production of plasmin. Ann-II-mediated enhancement of t-PA-dependent PLG activation was inhibited by epsilon-aminocaproic acid or by pretreatment of Ann-II with carboxypeptidase B with the inhibitive rate being 77.8% and 77.0%, respectively. It was revealed that the effect of Ann-II on PLG activation was specific for t-PA. Urokinase didn't bind to Ann-II, demonstrating the role of receptor-related lysine residues on activation of PLG, showing that the Ann-II-PLG interaction was dependent upon carboxyl-terminal lysine residues. These findings suggest that annexin II-mediated co-assembly of t-PA and PLG may promote plasmin generation and play a key role in modulating fibrinolysis on the endothelial surface.

Annexin A2↗
PubMed1989

Radioimmunological determination of levonorgestrel and ethinylestradiol.

A sensitive and specific radioimmunoassay for ethinylestradiol (EE2) and levonorgestrel (LN) has been developed. Antisera were raised in rabbits after injection of EE2-6-carboxymethyloxime-aminocaproic acid and LN-3-carboxy-methyloxime linked to bovine serum albumin. The sensitivity of immunoassay was 15 pg/ml for EE2 and 10 pg/ml for LN. The cross-reactions showed a high specificity of the assay, and the accuracy and precision of this method satisfied the requirements for the investigation of pharmacokinetics. With this assay, although the recovery of the assay was not very high (the coefficient of variation 14.02% for EE2 and 10.27% for LN) when used to analyse diethylether extracts of biological fluids, a microquantitative metabolite of norethisterone (NET) and norethisterone-3-oxime (NETO), EE2 analogue in incubation solution with rat hepatocytes, was satisfactorily detected. The result showed that in vitro the amount of NETO transferred to EE2 analogue was three times as much as that of NET. It is necessary to further establish the identity and activity of the analogue, but these data will be found advantageous to the research of steroid-oxime.

Animals↗
PubMed2006

Minimizing perioperative blood loss and transfusions in children.

PURPOSE: To summarize the physiology and pathophysiology relevant to perioperative blood loss in children. Strategies to reduce blood losses are reviewed. METHODS: The literature was reviewed using the electronic library PUBMED and the Cochrane Database of Systematic Reviews. Relevant studies published in English or French with an English abstract are included. The following keywords were used: children, blood transfusion, surgical blood loss, erythropoietin, autologous blood, red blood cell saver, normovolemic hemodilution, desmopressin, aminocaproic acid, tranexamic acid, aprotinin, cardiac surgery, liver transplantation and scoliosis surgery. MAIN FINDINGS: For patients with idiopathic scoliosis, predonation with or without the addition of erythropoietin is a safe and effective way to avoid the use of allogenic blood products. For open heart procedures: whole blood of less than 48 hr is helpful for children of less than two years of age undergoing complex procedures; tranexamic acid may be helpful for cyanotic heart disease and, to a lesser degree, for reoperations; while anti-kallikrein blood levels of aprotinin may both reduce the need for allogenic blood transfusions and improve postoperative oxygenation in infants. CONCLUSION: Reducing perioperative allogenic blood transfusions is possible in pediatric patients provided that prophylactic measures are adapted to age, disease and type of surgery.

Animals↗
PubMed1984

Identification of blood in the pericardial cavity in dogs by two-dimensional echocardiography.

The echocardiographic characteristics of hemopericardium with and without thrombus formation were investigated in 10 dogs and compared with that of saline solution injected into the pericardial cavity. Injection of 80 to 120 ml of saline solution produced an echolucent space between both pericardial layers and was considered as the control image in each dog for comparison with hemopericardium. Injection of heparinized blood filled the pericardial cavity with irregular echoes of variable acoustical impedence. High-density echoes of irregular distribution were observed in 3 dogs, in 5 dogs the echoes were of low acoustical density and in 2 dogs blood echoes were present but scarcely visible. Injection of clotted blood in 9 dogs (adding 20 mg of protamin sulphate and 8 mg of aminocaproic acid) produced echoes of high acoustical density easily identified in the 2-dimensional echocardiographic images. In 4 dogs attenuation and damping controls were increased to the point where myocardial echoes disappeared, while intrapericardial echoes were still visible. Thus, hemopericardium with or without thrombus formation may be identified by 2-dimensional echocardiography and differentiated from other types of pericardial effusion of lower acoustical density. Echogenicity of fluid blood in the pericardial cavity may be related to blood stasis.

Animals↗
PubMed1988

Traumatic hyphema in a defined population.

From 1960 through 1984, traumatic hyphema was diagnosed in 248 residents (204 males and 44 females) of Olmsted County, Minnesota. The mean annual incidence rate was significantly greater (P less than .001) among males than among females: 20.2 per 100,000 population and 4.1 per 100,000, respectively. The overall mean annual rate was 12.2. A significant increase in the incidence rate in recent years was caused primarily by an increase in the number of sports-related injuries. Secondary hemorrhage occurred in 18 patients (7.3%) and was significantly (P less than .05) more frequent among patients whose initial hyphema filled more than one third of the anterior chamber. The low risk of secondary hemorrhage and associated serious sequelae suggests that the possible benefits from routine systemic administration of aminocaproic acid may not outweigh the costs and risks in populations similar to that of Olmsted County.

Adolescent↗
PubMed1990

Use of biotinylated inorganic pyrophosphatase for detection of biotin bound to solid support.

A colorimetric procedure to detect biotin bound to microtiter plates with a sensitivity down to 10(-16) mol was developed using biotinylated inorganic pyrophosphatase of Escherichia coli. Reaction of pyrophosphatase with 1 mM N-biotinyl-6-aminocaproic acid N-hydroxy-sulfonosuccinimide ester yielded a stable 87% active enzyme containing 5.6 mol biotin/mol. In the measurements of human immunoglobulin G, a biotinylated pyrophosphatase.streptavidin complex provided a sensitivity superior to that of conventional enzyme immunoassay due to low nonspecific binding. The new procedure was also more sensitive compared with that using biotinylated alkaline phosphatase. Together with high thermostability of pyrophosphatase and its substrate, low background staining allowed measurement of enzymatic activity to be performed at 60 degrees C for 4 h resulting in a marked increase in assay sensitivity.

Bacterial Proteins↗
PubMed1993

Perioperative approaches to coagulation defects.

Cardiac surgical procedures are known to be associated with coagulation defects and disordered hemostasis. Excessive perioperative and postoperative bleeding and the need for considerable volumes of blood and blood product transfusions are well recognized. The risks of blood transfusion with high donor-exposure levels have focused attention on blood conservation as a priority in reducing the complications of cardiac operations. Hemostatic defects may be related to patient-inherent coagulopathies, preexisting associated pathology, and preoperative drug therapy. In addition, hemostatic defects are induced during the operation itself. Two principal therapeutic approaches to this complex problem have evolved. Although different, these approaches are not mutually exclusive and may be used complementarily. The first is autotransfusion and the second is hemostatic drug therapy. Although many drugs have been tried, including antifibrinolytic agents (epsilon-aminocaproic acid, tranexamic acid), platelet-preserving agents (prostacyclin, dipyridamole), and desmopressin, the only drug that has shown significant and consistent efficacy in reducing bleeding in cardiac surgery patients is the serine protease inhibitor aprotinin. Aprotinin has been shown to be highly effective in reducing blood loss and blood and blood product transfusion requirements in high-risk patients. Clinical experience with aprotinin therapy in cardiac patients and specific issues such as dosage regimens and the target automated clotting time levels in patients on high-dose aprotinin therapy are outlined. Indications for the use of aprotinin and the balance between risk and benefit are discussed.

Aprotinin↗
PubMed1985

Purification and partial characterization of ceruloplasmin from chicken serum.

The preparation and properties of ceruloplasmin from chicken serum are described. Ethanol-CHCl3 was used to precipitate the crude protein, followed by adsorption and elution from DEAE-Sephadex. Further treatment with Sephadex G-200 and CM-Sephadex yielded an intensely blue protein judged 1572-fold purer than starting serum. epsilon-Aminocaproic acid (0.02 M) was present in all buffers and starting sera. Chicken ceruloplasmin appears to be a single polypeptide, apparent Mr 124,000, with an A610/A280 ratio of 0.07 and an absorption maximum at 602 nm. Hexose, hexosamine, and sialic acid accounted for 7.2% of the weight; copper represented 0.20%, which suggested four or five copper atoms per molecule. Chicken ceruloplasmin catalyzed the azide-sensitive oxidation of p-phenylenediamine (PPD) and N,N'-dimethyl-p-phenylenediamine (DPD), and showed ferroxidase activity similar to that of human ceruloplasmin. Its amino acid composition, although similar in many residues to human ceruloplasmin, was decidedly lower in methionine and tyrosine. The chicken protein had one-third the sialic acid content of human ceruloplasmin and showed immunochemical nonidentity with human ceruloplasmin.

Amino Acids↗
PubMed1986

Secondary structure predictions of human plasminogen and the bovine prothrombin kringle loops.

Secondary structural predictions, based upon the statistical methodology of Chou and Fasman, for the kringle loops of human plasminogen and bovine prothrombin suggest a "winding staircase" pattern of beta-turns, spaced by short regions of ordered and coil structures. Analysis of the predicted structures of the regions containing the two His (113 and 387) and Asp (136 and 410) residues in plasminogen kringles 1 and 4, which have been found to be important in binding the ligand, epsilon-aminocaproic acid, shows that all are localized at the same positions on beta-turns. In addition, both of the two Asp residues occur at the end of homologous nonapeptide regions common to all of the five human plasminogen and two bovine prothrombin kringles, indicating evolutionary conservation to preserve biologically critical conformations. Examination of the protein conformation in the region of Asn288, the residue which is glycosylated in one of the two circulating variants of human plasminogen, shows that it most likely exists in a position which may present topographical hindrance to post-translational attachment of carbohydrate, thus, possibly, explaining the incomplete glycosylation of human plasminogen with complex-type carbohydrate.

Amino Acid Sequence↗
PubMed1986

1H-NMR spectroscopic manifestations of ligand binding to the kringle 4 domain of human plasminogen.

Structural aspects of the binding of the linear ligands N alpha-acetyl-L-lysine (AcLys) and epsilon-aminocaproic acid (epsilon ACA) and of the cyclic analogs trans-(aminomethyl)-cyclohexanecarboxylic acid (AMCHA) and p-benzylaminesulfonic acid (BASA) to the intact plasminogen kringle 4 domain have been investigated by 1H-NMR spectroscopy at 300 and 600 MHz. Ligand binding results in consistent shifts of the His-II (His31), Trp-I (Trp25?), Trp-II (Trp62?), Trp-III (Trp72), Tyr-II (Tyr50), and Phe64 ring signals. BASA tends to induce larger shifts than elicited by the aliphatic ligands, most noticeably on Trp-II and on Trp72, suggesting that the ligand aromatic ring interacts with the two indole groups. Trp-II and, to lesser extent, Trp-I interact with an acidic side chain group, in a manner that is blocked by BASA. BASA binding also perturbs Tyr-II (Tyr50), Tyr-III (Tyr41), and Tyr-IV (Tyr74) over a wide pH range and lowers the pKa* of His31 from approximately 4.8 to approximately 4.6. His-III (His33) responds to BASA and AMCHA but is relatively insensitive to the linear ligands. His33 carries a sterically shielded side chain which, in conjunction with Leu46, Trp-I, Tyr50, and Tyr74, participates in structuring the kringle hydrophobic core, contiguous to the binding site. Pronounced shifts are observed for aliphatic resonances stemming from the kringle-bound molecules of AMCHA, AcLys, and epsilon ACA. It is proposed that the lysine-binding site is mostly supported by the loop that extends from Cys51 through Cys71 and that aromatic residues, which include Trp-II, Trp72, and Phe64, play a major role in interacting with the nonpolar segment of the ligand molecule. The binding site also encompasses Tyr50, Tyr74, His31, and His33 although it is not clear the extent to which these residues interact directly with the ligand.

Benzylamines↗