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NAG Abstracts

Overview » Return to Hemostasis

The accompanying papers were presented during a symposium at the Brigham and Women’s Hospital, held on 25 February 2003. Taken together the animal and clinical data indicate that poly-N-acetyl glucosamine, an FDA approved agent manufactured by Marine Polymer Technologies Inc. is an effective hemostatic agent whether applied directly to gastric varices; topically against bleeding surfaces of spleen or liver; against major wounds of the abdominal aorta; or somewhat more remotely from the vascular injury, that is on cardiac cathetherization sites in the groin. These studies represent data from animal and human observations. Most of the studies were done in a blinded fashion with proper controls. The only problem with controlling the poly-N-Acetyl glucosamine patch was that it often adhered with somewhat more tenacity than the control cellulose or deacetylated patches. Thus some of the patch effects could be mechanical, although in most studies this appeared to be a relatively insignificant action.

What makes these results even more striking is that positive hemostasis was achieved, even in the presence of full heparinization and in acquired and congenital hemostatic defects. The mechanism of action could still be via activation of the clotting cascade via either platelet or red cell activation. That poly-N-Acetyl glucosamine is a potent inducer of these actions has been conclusively shown in several papers. However to document the role of clotting in the clinical studies it will be necessary to quantitate fibrin formation in the region of the vascular or solid organ injury.

That clotting factors may not be necessary to achieve hemostasis was shown in an in-vitro study of aortic injury. Additional data in three studies indicate that an endothelial dependent vasoconstrictor is produced which makes possible the induction of hemostasis via vascular contraction. The vasoconstrictor appears to be endothelin, largely based on the ability of receptor antagonists to nullify the action of poly-N-Acetyl glucosamine. However, neither ELISA nor immunohistochemistry have been able to show a reduction in big endothelin or rise in levels of endothelin at the site of vascular injury. This may be related to problems with antibody binding.

The clinical and preclinical data support a potential role for poly-N-Acetyl glucosamine in a variety of medical and surgical conditions and particularly in trauma. The formulation of a more rapidly metabolized product would greatly expand its clinical use since it would permit clinicians to leave it in situ much as is done with Surgicel.

ISOLATION, PURIFICATION AND CHARACTERIZATION OF POLY-N-ACETYL GLUCOSAMINE FOR USE AS A HEMOSTATIC AGENT

COMPARISON OF POLY-N-ACETYL GLUCOSAMINE WITH ABSORBABLE COLLAGEN, OXIDIZED REGENERATED CELLUOSE AND CHITOSAN FOR ACHIEVING HEMOSTASIS IN COAGULOPATHIC ANIMAL MODELS OF SPLENIC HEMORRHAGE

APPLICATION OF THE POLY-N-ACETYL GLUCOSAMINE DERIVED RAPID DEPLOYMENT HEMOSTATIC (RDH) TRAUMA DRESSING IN SEVERE/LETHAL SWINE HEMORRHAGE TRAUMA MODELS

AN EVALUATION OF THE EFFICACY OF A POLY-N-ACETYL GLUCOSAMINE MEMBRANE MATERIAL AS A TOPICAL HEMOSTATIC AGENT AS COMPARED TO ABSORBABLE COLLAGEN (ACTIFOAM®), OXIDIZED CELLULOSE (SURGICEL®) AND FIBRIN SEALANT (TISSEEL®, TACHOCOMB®) MATERIALS

A BLINDED RANDOMIZED STUDY TO EVALUATE POLY-N-ACETYL GLUCOSAMINE AS A HEMOSTATIC AGENT IN PATIENTS UNDERGOING CARDIAC CATHETERIZATION

RANDOMIZED DOUBLE BLIND STUDY OF POLY-N-ACETYL GLUCOSAMINE GEL COMPARED TO GLUE AND OTHER AGENTS FOR ENDOSCOPIC HEMOSTASIS OF BLEEDING CANINE GASTRIC VARICES

RAPID DEPLOYMENT HEMOSTAT (RDH) BANDAGE REDUCES BLOOD LOSS AND MORTALITY IN COAGULOPATHIC PIGS WITH SEVERE LIVER INJURY

VASCULAR EFFECTS of POLY-N-ACETYLGLUCOSAMINE In ISOLATED RAT AORTIC RINGS

IN VITRO EFFECTS OF POLYMERIZED N-ACETYLGLUCOSAMINE (NAG) ON PLATELETS WITH AND WITHOUT RED BLOOD CELLS ON THE ACTIVATION OF PLATELETS AND RED BLOOD CELLS LEADING TO CLOTTING

EFFICACY OF THE POLY-N-ACETYL GLUCOSAMINE (NAG) PATCH IN A MODEL OF EVERE HEMORRHAGE

POLY-N-ACETYL GLUCOSAMINE (NAG) HEMOSTASIS IN THE ABSENCE OF CLOTTING FACTORS

HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL STUDIES ON THE INTACT AND PUNCTURED RAT AORTA

MOLECULAR MECHANISMS INVOLVED IN OF POLY-N-ACETYL GLUCOSAMINE POLYMER MEDIATED HEMOSTASIS

MECHANISM OF PLATELET INTERACTION WITH POLY-N-ACETYL GLUCOSAMINE FOR HEMOSTASIS

Title: ISOLATION, PURIFICATION AND CHARACTERIZATION OF POLY-N-ACETYL GLUCOSAMINE FOR USE AS A HEMOSTATIC AGENT
Authors:

John N.Vournakis, Ph.D., Marina Demcheva, Ph.D., Anne Whitson, M.S., Radu Guirca, Ph.D. and Ernst R. Pariser
Marine Polymer Technologies, Inc., Burlington, Massachusetts

Background: A natural, proprietary, biodegradable and biocompatible polymer matrix, poly-N-acetyl glucosamine (p-GlcNAc), has been developed that is effective in achieving hemostasis in a variety of medical procedures and in the control of bleeding resulting from trauma.
Methods: The p-GlcNAc and its derivatives have been formulated as films, sponges, hydrogels, microspheres and fibers. Biocompatibility testing performed included cytotoxicity, primary skin irritation, sensitization assay, systemic toxicity, hemocompatibility, pyrogenicity, mutagenicity and sub-chronic toxicity.
Results: The primary sugar present in the material is acetylated N-acetyl glucosamine and the polymer has a weight average molecular weight of 2.0 million Daltons. In vivo results indicate that materials have controlled rates of in-vivo biodegradability and these substances are biocompatible.
Conclusion: A unique polysaccharide polymer isolated from marine microalgae has been identified. The p-GlcNAc polymer has an excellent biocompatibility profile and is manufactured following FDA guidelines.

Title: COMPARISON OF POLY-N-ACETYL GLUCOSAMINE WITH ABSORBABLE COLLAGEN, OXIDIZED REGENERATED CELLUOSE AND CHITOSAN FOR ACHIEVING HEMOSTASIS IN COAGULOPATHIC ANIMAL MODELS OF SPLENIC HEMORRHAGE
Authors: Steven D Schwaitzberg, MD, Michele W. Chan, MD, Raymond J Connolly, PhD
Department of Surgery New England Medical Center, Boston, MA
Background: The hemostatic qualities of poly-N-acetyl glucosamine were compared with several currently available products.
Methods: These studies were performed in immature female Yorkshire White swine, hemophiliac dogs, and rabbits. Splenic lacerations controlled for length and depth of wound were used as sources of bleeding to assess hemostatic effectiveness. Hemostatic efficacy was judged by the number of cycles of compression of the test materials needed to achieve complete hemostasis in each model.
Results: In systemically heparinized animals, in the hemophilia B dogs and in the hypothermic animals p-GlcNAc exerted a better hemostatic effect than did Actifoam, Surgicel, and the two chitosan products.
Conclusion: The results in animals with acquired and genetic hemostatic defects demonstrate that p-GlcNAc in the form of a membrane or patch is a more effective topical hemostatic agent than Actifoam, Surgicel or two (2) chitosan products CLO-SUR P.A.D. and Chito-Seal.

Title: APPLICATION OF THE POLY-N-ACETYL GLUCOSAMINE DERIVED RAPID DEPLOYMENT HEMOSTATIC (RDH) TRAUMA DRESSING IN SEVERE/LETHAL SWINE HEMORRHAGE TRAUMA MODELS
Authors:

Raymond J. Connolly, Ph.D.
Department of Surgery, New England Medical Center, Boston, Massachusetts 02111

Background: This study compared the hemostatic capabilities of the RDH Bandage with the standard bandages utilizing lethal trauma models of hemorrhage.
Methods: A swine model was designed to simulate extremity injuries and abdominal aorta hemorrhage. Hemostatic efficacy was judged by the total loss of blood, and the survival of the animals.
Results: RDH Bandage reduced blood loss by 63% compared to the gauze standard of care material. Eighty percent (80%) of the animals treated with the RDH Bandage survived, whereas only forty percent (40%) of those treated with the Army First Aid Field Bandage survived. The average blood loss for the RDH Bandage treated animals was 234ml, whereas the average blood loss for the Army First Aid Field Bandage treated animals was 1071ml.
Conclusion: The RDH bandage was significantly superior to gauze, Tachocomb, fibrin bandage, and the standard U.S. Army First Aid Field Bandage to decrease blood loss and increase survival.

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Title: AN EVALUATION OF THE EFFICACY OF A POLY-N-ACETYL GLUCOSAMINE MEMBRANE MATERIAL AS A TOPICAL HEMOSTATIC AGENT AS COMPARED TO ABSORBABLE COLLAGEN (ACTIFOAM®), OXIDIZED CELLULOSE (SURGICEL®) AND FIBRIN SEALANT (TISSEEL®, TACHOCOMB®) MATERIALS
Authors: David J. Cole, MD1, Ray J. Connolly, PhD.2, Michele W. Chan, MD2, Steven D. Schwaitzberg MD2, and Paul H. O'Brien MD1
Medical University of South Carolina, Dept. of Surgery,1, New England Medical Center Dept. of Surgery, Surgical Research Laboratory2
Background: This study was performed to evaluate the effectiveness of a particular formulation of the polysaccharide polymer, poly-N-acetyl glucosamine (p-GlcNAc), as a topical hemostatic agent for use in the operating room.
Methods: Female Yorkshire white swine were subjected to splenic incisions and splenic capsular stripping: p-GlcNAc patches and membranes, oxidized regenerated cellulose, collagen, the fibrin sealant or fibrin bandage were assessed as hemostatic agents.
Results: The p-GlcNAc membrane required fewer cycles of compression in the swine splenic incision model to achieve hemostasis than either Actifoam® or Surgicel® . In the splenic capsular stripping, p-GlcNAc required fewer cycles of compression to achieve hemostasis than Surgicel®, Tisseel® and Tachocomb®.
Conclusion: Greater hemostatic efficacy of p-GlcNAc was observed compared to collagen, oxidized cellulose or fibrin sealant based products in the studies performed using the swine spleen.

Title: A BLINDED RANDOMIZED STUDY TO EVALUATE POLY-N-ACETYL GLUCOSAMINE AS A HEMOSTATIC AGENT IN PATIENTS UNDERGOING CARDIAC CATHETERIZATION
Authors: Khuri, S.F., Najjar, S.F., Healey, N.A., Healey, C.M., McGarry, T., Khan, B., Thatte, H. S., and Welt, F.GS.*
Departments of Surgery and Cardiology*, VA Boston Healthcare System, Boston, Massachusetts
Background: Hemostasis following arterial puncture for cardiac catheterization is currently achieved by applying pressure to the puncture site.
Objective: This is the first blinded, randomized, placebo-controlled clinical trial to evaluate the efficacy of poly-n-acetyl glucosamine to improve hemostasis in patients undergoing cardiac catheterization.
Methods: Patients were randomly assigned to have either a placebo-treated (n=17) or poly-n-acetyl glucosamine-treated (n=16) 3x3 cm patch topically placed at the femoral insertion site at the conclusion of their catheterization procedure with a mechanical pressure clamp applied over it.
Results: No differences were seen in the pre-catheterization hematocrit, bleeding time, and activated clotting time. There was also no difference in the clamp pressure applied to the femoral arterial puncture site at the end of the catheterization procedure. The time to effect hemostasis was decreased by 38% when the poly-n-acetyl glucosamine treated patch was used.
Conclusion: The application of poly-n-acetyl glucosamine-treated patches improved hemostasis at the arterial puncture site in patients undergoing cardiac catheterization.

Title: RANDOMIZED DOUBLE BLIND STUDY OF POLY-N-ACETYL GLUCOSAMINE GEL COMPARED TO GLUE AND OTHER AGENTS FOR ENDOSCOPIC HEMOSTASIS OF BLEEDING CANINE GASTRIC VARICES.
Authors: Jensen, D.M., Machicado, G.A. and Hirabayashi, K.*
UCLA School of Medicine/VA GLAHS, Los Angeles, CA, and VA Greater Los Angeles Healthcare System, Los Angeles, CA*
Background: A study was performed to compare a 1% and 3% poly-N-acetyl glucosamine gel with glue (n-butyl cyanoacrylate), a sclerotherapy mixture (3.3% ethanolamine+32% alcohol—EA) and saline (control) for safety and efficacy in a double blind study of bleeding gastric varices (GV).
Methods: Adult mongrel dogs with prehepatic portal hypertension and 5 to 6 moderate to large sized gastric varices were heparinized. Bleeding was induced with a 19—gauge needle. Each bleeding GV was randomized to endoscopic treatment with the methylene blue treated solutions The endoscopist was blinded to the solutions and the code was not broken until the final data analysis.
Results: Glue had a high rate of primary hemostasis, but the highest ulceration rate and no GV size change at 1 week. EA sclerosant mixture had a low primary hemostasis rate, but a moderately high ulceration rate and GV grade reduction at 1 week, poly-N-acetyl glucosamine gel at 1% and 3% had high rates of primary and 5 min hemostasis, significant reduction of GV size, and low ulceration rates at 7 days.
Conclusion: N-acetyl glucosamine gels restored hemostasis at the bleeding gastric varices in dogs and reduced the size of the gastric varices.

Title: RAPID DEPLOYMENT HEMOSTAT (RDH) BANDAGE REDUCES BLOOD LOSS AND MORTALITY IN COAGULOPATHIC PIGS WITH SEVERE LIVER INJURY
Authors: Cohn, S.M., MD, Jewelewicz, D., MD, Nelson, J., MD, Bonet, J., MD, Crookes, B.A., MD, and Proctor, K.G., PhD
Daughtry Dept of Surgery, Ryder Trauma Center, Univ. of Miami School of Medicine, Miami, FL
Background: Hemostasis can be difficult to achieve after blunt abdominal trauma, particularly if the patient has a bleeding disorder. The RDH bandage was evaluated as an adjunct to standard laparotomy packing after severe liver injury.
Methods: Anesthetized swine received a 45% blood volume replacement with cold 6% hetastarch. Core body temperature was maintained at 33-34o C. Liver injury was induced by the avulsion of the left lateral hepatic lobe. Animals were randomized to standard abdominal packing (control) or standard packing plus RDH bandage.
Results: The RDH treated swine had survival time of 170 minutes, a 3 hour survival of 80% , total blood loss of 0.26 ml/kg/min and total fluids of 0.57 ml/kg/min compared to the survival time of 78 minutes, zero survival at 3 hours, total blood loss of 1.23 ml/kg./min, and total fluids of 1.57 ml/kg/min.
Conclusion: The RDH bandage when used as an adjunct to standard abdominal packing following severe liver injury reduced blood loss, and fluid requirements leading to improved survival.

Title: VASCULAR EFFECTS of POLY-N-ACETYLGLUCOSAMINE In ISOLATED RAT AORTIC RINGS
Authors: Lefer, A.M., Ph.D., Ikeda, Y., MD, and Young, L.H., Ph.D.
Department of Physiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
Background: This study was done to determine whether p-GlcNAc induced a significant vasoconstrictor effect and, if so, what the mechanism of this effect might be.
Materials & Methods: Vascular effects of p-GlcNAc on isolated aortic rings obtained from Sprague-Dawley rats were studied. The rings were suspended in organ baths and precontracted with U46619, a thromboxane A2 mimetic.
Results: P-GlcNAc produced a concentration-dependent vasoconstriction over the range of 14 to 100 µg/ml. At a concentration of 100 µg/ml, p-GlcNAc significantly contracted aortic rings by 133 + 20 mg of developed force (P<0.01). Neither a deacetylated derivative of p-GlcNAc nor a structurally related macro-molecule, chitin, contracted rat aortic rings. The vasocontriction to p-GlcNAc was totally abolished in deendothelialized rat aortic rings. Pretreatment with the endothelin ETA receptor antagonist significantly diminished p-GlcNAc induced vasoconstriction by 57 to 61% (P<0.01).
Conclusion: p-GlcNAc significantly contracts isolated rat aortic rings via an endothelium-dependent mechanism, partly via enhancement of endothelin-1 release from endothelial cells.

Title: IN VITRO EFFECTS OF POLYMERIZED N-ACETYLGLUCOSAMINE (NAG) ON PLATELETS WITH AND WITHOUT RED BLOOD CELLS ON THE ACTIVATION OF PLATELETS AND RED BLOOD CELLS LEADING TO CLOTTING
Authors: Valeri, C.R., Srey, R., Tilahun, D., and Ragno, G.
Naval Blood Research Laboratory, Boston University School of Medicine,
Boston, MA
Background: This study was done to assess the effect of NAG on plasma clotting proteins, platelets and red blood cells in the clotting of the blood.
Study Design and Methods: CPD whole blood was stored at 22 C for 48 hours to prepare: platelet poor plasma (PPP), platelet rich plasma (PRP), and PRP plus red blood cells with hematocrit values of 20 V%, 35 V% and 45 V% with and without an equal volume of NAG (1 mg/ml 0.9% NaCl).
Results: In the thromboelastogram, NAG reduced the R time in PPP, PRP and PRP supplemented with RBC. NAG increased annexin V and factor X binding to platelets, increased platelet microparticles, and increased RBC annexin V binding. NAG and RBC in combination increased thromboxane A2 production by platelet rich plasma. NAG, platelet-rich plasma and red blood cells reduced the fibrinogen level with the higher hematocrit values associated with lower fibrinogen levels.
Conclusion: Polymerized N-acetylglucosamine (NAG) affects the clotting of blood by activation of the plasma clotting proteins, platelets and RBC.

Title: EFFICACY OF THE POLY-N-ACETYL GLUCOSAMINE (NAG) PATCH IN A MODEL OF SEVERE HEMORRHAGE
Authors: Wilfred Lieberthal, Robert Fuhro, C. Robert Valeri
Boston University School of Medicine
Background: The efficacy of the application of the poly-N-acetyl glucosamine (NAG) patch applied with pressure in improving survival following aortic puncture in rats was assessed.
Methods: Rats were anesthetized with sodium pentobarbital and the abdomen opened by a midline incision. A 23-gauge hypodermic needle was used to puncture the ventral wall of the aorta approximately 1 cm above the aortic bifurcation. The needle was removed and the patch immediately applied with pressure for 30 seconds. Three types of patches were compared; sham (n=26), dried NAG (D-NAG)(=25) and lyophilized NAG (LYO-NAG)(n=20) for adhesion, sealing and blood loss.
Results: Adhesion: Sham 39%; D-NAG 100% and LYO-NAG 95%. Sealing: Sham 8%; D-NAG 29% and LYO-NAG 30%. Survival: Sham 73%; D-NAG 72% and LYO-NAG 90%. Blood loss: Sham 5.5±0.5ml; D-NAG 5.5±0.6ml and LYO-NAG 4.1±0.7ml.
Conclusion: The D-NAG and LYO-NAG patches were far more effective than sham patches at adhering to and sealing the puncture wound. No difference in survival between sham patch and D-NAG patch-treated rats was observed. The LYO-NAG patch-treated rats had an improved survival compared to the other two groups.

Title: POLY-N-ACETYL GLUCOSAMINE (NAG) HEMOSTASIS IN THE ABSENCE OF CLOTTING FACTORS
Authors: Hechtman, H.B., MD and Favuzza, J.
Department of Surgery, Brigham and Women’s Hospital, Boston MA 02115
Background: This study investigated the thesis that one mechanism of NAG action is to induce release of a local vasoconstrictor e.g. endothelin, leading to smooth muscle contraction of the vessel wall and closure of the laceration. 
Methods: The infra-renal aorta of an anesthetized rat was dissected free. Ligatures were placed proximally and distally at the formation of the common iliac arteries. A 22 gauge cannula was inserted into the 2-3 cm aortic segment. The ligatures were tied as the aorta was flushed with saline. A reservoir with 60 ml saline, fixed at a height of 80 cm was connected to the cannula. The period of low pressure in the aortic segment was limited to 10–15 sec. A through and through aortic injury was made with a 23 gauge needle. The time taken to empty the reservoir was recorded.
Results: Application of a control patch (n=10) about the aortic injury sites led to an emptying time of 295 sec while a NAG patch (n=6) increased this time to >600 sec (p<0.05). Ten min after removal of the NAG patch emptying time decreased to baseline, 330 sec. Rats were treated iv with the endothelin receptor antagonists BQ-485 (n=6) or JKC-301 (n=4). Emptying time was shortened, despite the NAG patch to control values.
Conclusion: Poly-NAG is an effective topical hemostatic agent whose mechanism of action is via endothelin release. This action is observed in the absence of any formed elements of blood.

Title: HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL STUDIES ON THE INTACT AND PUNCTURED RAT AORTA
Authors: Friend, D., Ph.D. and Favuzza, J.
Department of Surgery and Pathology, Brigham and Women’s Hospital, Boston, MA 0115.
Background: Studies with injured rat aortas indicate that hemostasis induced by poly N-acetyl glucosamine (NAG) can be inhibited by using an endothelin-1 antagonist. The amount and localization of poly-n-acetyl glucosamine, endothelin and big endothelin on the endothelial surface of the intact and punctured rat aortas were investigated.
Methods: The rat aorta was exposed to the gold labeled plant lectins, tritium vulgare and solanum tuberosum, both of which bind to n-acetyl glucosamine. The aorta was immunolabeled with IgG to detect endothelin or big endothelin. Antibodies to Factor VIII and to smooth muscle actin served as controls for endothlial and muscle wall labeling. The sections were examined and photographed on a Leica transmitted light microscope. Fresh aortic specimens were assayed for endothelin and big endothelin by ELISA.
Results: The assays of endothelin and big endothelin revealed no change after aortic injury or application of NAG.
Conclusion: These data did not indicate that endothelin mediates the hemostatic events following aortic injury and application of NAG.

Title: MOLECULAR MECHANISMS INVOLVED IN OF POLY-N-ACETYL GLUCOSAMINE POLYMER MEDIATED HEMOSTASIS
Authors: Thatte, H. S., Ph.D., Zagarins, S. and Khuri, S.F., MD
Department of Surgery, VA Boston Healthcare System, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115.
Background: The topical application of poly- N-acetyl glucosamine at the wound site leads to rapid hemostasis. The molecular mechanism of this action has not been determined.
Methods: NAG interactions with human and porcine whole blood, RBC and platelets were evaluated using multi-photon imaging and spectrophotometry.
Results: In vitro clot formation, RBC aggregation and platelet activation occurred within 3-5 minutes (T1/2) and reached their maximum (Tmax) at 10-15 min, respectively. The NAG slurry and alpha modification of NAG gave maximum response, in contrast, deaceytlated NAG and chitosan were found to be ineffective . Glycosylated cell surface receptors on RBC, and integrins on platelets were found to be involved in blood cell-NAG interactions. These interactions were calcium and magnesium-dependent, and were mediated via cell surface ionic charge, and phosphotidylserine exposure.
Conclusion: Poly-NAG induced thrombogenesis is mediated via ionic interactions and cell surface receptors on the blood cells. The hemostatic mechanism of NAG may be mediated through its interactions with blood cells at the wound site.

Title: MECHANISM OF PLATELET INTERACTION WITH POLY-N-ACETYL GLUCOSAMINE FOR HEMOSTASIS
Authors: Fischer, T.H. and Merricks, E.P.
Department of Pathology and Laboratory Medicine, Francis Owen Blood Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27516
Background: Experiments were undertaken to determine the chemical and physical processes that are involved in the interaction of platelets with poly-N-acetyl glucosamine leading to hemostasis.  
Methods: Human platelets labeled with biotin-NHS were mixed with NAG polymers in the presence or absence of the inhibitors of the fibrinogen receptor alpha2bbeta3 , factor XIIa and thrombin. Measurements were made of scanning electron and fluorescent microscopy, SDS page electrophoresis, Western analysis and the effect of NAG on fibrin-gel formation and clot retraction.
Results: The interaction of platelets with NAG resulted in shape-change and pseudopodia extension, as well as the expression of fibrinogen and p-selectin from platelet alpha granule. Platelets bound to the NAG polymer to form NAG~fibrin~platelet macro-aggregates.
Conclusion: NAG binds directly to platelets and fibrinogen, activates factor XIIa to generate thrombin, and produces fibrin polymerization and clot retraction.

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