Fibrinogen

Perinatal care in Japan has progressed rapidly in recent decades, remarkably reducing maternal, perinatal and neonatal mortality rates. This is attributable not only to the sustained efforts and dedication of past obstetricians and midwives, but also to the collective results achieved by the Japan Society of Obstetrics and Gynecology and healthcare administration, including research on advanced medical care, education, medical care improvements and establishing perinatal care centers. Although the maternal mortality rate was in steady decline until 2007 (3.1/100 000 births), it repeatedly fluctuated thereafter, plateauing at 3.4 per 100 000 births in 2013 and 2.7 per 100 000 births in 2014. Thus, the Perinatology Committee has analyzed the current situation of maternal deaths and has proposed countermeasures to reduce such death. The items deliberated upon by related subcommittees in 2015 are presented herein. The addition of indications for 'fibrinogen concentrate', 'ep...

Surface-coated cardiopulmonary bypass (CPB) has been shown to have excellent biocompatibility during cardiac surgery in adults, but there have been only a few reports demonstrating the efficacy of this coating for congenital cardiac surgery. We tested the efficacy of poly-2-methoxyethylacrylate (PMEA) coating for CPB circuits in congenital cardiac surgery. Eleven operative cases of ventricular septal defect were studied: group C (control: no coating, n = 5) and group P (PMEA coating, n = 6). The platelet count and beta-thromboglobulin (beta TG), fibrinogen (FBG), thrombin-antithrombin complex (TAT), and neutrophil elastase levels were measured during the operation. Postoperative chest tube drainage was analyzed and the surface of the artificial lung was observed with an electron microscope. Elevation of TAT and neutrophil elastase was suppressed in group P (P < 0.05). Observation of the artificial lung surface using an electron microscope clearly revealed fewer blood cells were a...

This is the first European study that has evaluated educational level in a large sample of hypertensive outpatients. We established the educational level of the hypertensive outpatients in our unit, and determined whether the awareness of hypertension and its organ damage was education-related. We analysed data from 812 consecutive outpatients (378 men, mean age 50 +/- 10 years) with essential stage I-II hypertension. Subjects were subdivided into two categories: group A subjects were highly educated; group B subjects had a little education. Data were compared with educational level from the 1991 population census for the Campania region (ISTAT data) and with 200 type 2 diabetes patients (96 men, mean age 51 +/- 9 years) from the nearest diabetes unit. For each hypertensive patient we considered clinical, echocardiographic and biochemical parameters. Data from the last census showed a high percentage (80%) of subjects with low education. The percentage of type 2 diabetic patients with little education was high (190 patients, 95%). Conversely, it is somewhat surprising that most hypertensive patients reached high standards of education and worked at sedentary jobs (group A: 736 patients, 91%; P < 0.0001). Multivariate analysis showed that only diastolic blood pressure (P = 0.03) was independently associated with low educational level. Compared to diabetes, hypertension and its risk factors are relatively unknown to people with little education. Education is associated with greater health care and awareness that may overcome the risk related to low physical activity. Thus, we stress the importance of a sound health policy able to reach out to the uneducated and make them aware of hypertension and the health care services available to them.

The imbalance in clotting homeostasis, tending towards hypercoagulation, is recognized as the real barrier to the long-term survival of porcine xenografts in pig-to-primate xenotransplatation. The present study aimed to validate in primate blood the applicability of whole blood rotation thromboelastometry, performed by ROTEM®, which evaluates the characteristics of clot formation by dynamic monitoring.ROTEM® (Pentapharm GmbH, Munich, Germany) was used to investigate native coagulation (NATEM®), the intrinsic (INTEM®) and extrinsic (EXTEM®) pathways, the function of fibrinogen (FIBTEM®), and the presence of fibrinolysis in 40 naïve cynomolgus monkeys. Using classic validation approaches, the normal thromboelastographic profile was defined and the influence of haematocrit (Hct,%), platelet count (x109/L), fibrinogen (mg/dl), and factor VIII (FVIII,%) was evaluated.In all four (NATEM®, INTEM®, EXTEM®, FIBTEM®) assays considered, Clotting Time (CT, sec) and Clot Formation Time (CFT, sec) were shorter in primates than humans. Moreover, α-angle (°), Maximum Clot Firmness (MCF, mm), and MaxVel (mm/min) were also higher in primates than humans. No substantial difference was observed for Hct and platelet count between the two species. On the contrary, FVIII was higher in primates than in humans whereas, interestingly enough, fibrinogen levels were lower in monkeys than in humans.ROTEM® depicts a hypercoagulable profile in primates as compared to humans. Taken together these data suggest that, with regard to coagulation, xenotransplantation in cynos may represent a much more difficult situation than xenotransplantation in humans.

Interaction of fibrin with endothelial cells through their receptor VE-cadherin has been implicated in modulation of angiogenesis and inflammation. Previous studies identified the VE-cadherin-binding site in the fibrin βN-domains formed by the NH2-terminal regions of fibrin β chains, and revealed that the recombinant dimeric (β15-66)2 fragment mimicking these domains preserves the VE-cadherin-binding properties of fibrin. To test if the other fibrin(ogen) regions/domains are involved in this interaction and localize the complementary fibrin-binding site in VE-cadherin, we prepared several recombinant fragments containing individual extracellular domains of VE-cadherin or combinations thereof, as well as several fragments corresponding to various fibrin(ogen) regions, and tested the interactions between them by ELISA and surface plasmon resonance. The experiments revealed that the βN-domains are the only fibrin(ogen) regions involved in the interaction with VE-cadherin. They also loc...

The genus Citrus of the family Rutaceae includes many species e.g. Citrus indica, Citrus aurantifolia and Citrus limon, among which Citrus limon L. Burm. f. has been reported to have highest antimicrobial activity. It is used as antidote against certain venom, due to its platelet inhibitory effect and also reported to have hypocholesterolemic effect. However its anticoagulant and thrombolytic effect were not been investigated, hence a prospective in-vitro/in-vivo study was designed to determine the effect of Citrus limon on blood parameters, coagulation and anticoagulation factors. In-vitro tests revealed highly significant increase in thrombin time and activated partial thromboplastin time by Citrus limon, whereas fibrinogen concentration was significantly reduced in comparison to control, however prothrombin time was not affected significantly. In-vivo testing of Citrus limon was done at three different doses i.e. 0.2ml/kg, 0.4ml/kg and 0.6ml/kg in healthy rabbits. Significant cha...

The aim of this study is to elucidate the role of integrins in transducing fluid shear stress into intracellular signals in vascular endothelial cells, a fundamental process in vascular biology. We demonstrated that shear stress activates specific integrins in endothelial cells plated on substrates containing the cognate extracellular matrix (ECM) ligands. The shear stress-induced mechanotransduction, as manifested by integrin-Shc association,

Activated platelets bind numerous adhesive and procoagulant proteins by receptor-mediated processes. Although there is little evidence to suggest that these processes are heterogeneous in platelets, we previously found that platelets co-stimulated with collagen and thrombin express functional alpha-granule factor V only on a subpopulation of cells. Here we show that these cells, referred to as 'COAT-platelets', bind additional alpha-granule proteins, including fibrinogen, von Willebrand factor, thrombospondin, fibronectin and alpha2-antiplasmin. These proteins are all transglutaminase substrates, and inhibitors of transglutaminase prevent the production of COAT-platelets. A synthetic transglutaminase substrate (CP15) also binds to COAT-platelets, and analysis by high performance liquid chromatography/mass spectrometry shows that a product is formed with a relative molecular mass (Mr) equal to CP15 plus 176. Serotonin, an abundant component of platelet-dense granules, has an ...

We have isolated selective ligands to the cell surface receptors of fibronectin (alpha 5 beta 1 integrin), vitronectin (alpha v beta 3 and alpha v beta 5 integrins) and fibrinogen (alpha IIb beta 3 integrin) from phage libraries expressing cyclic peptides. A mixture of libraries was used that express a series of peptides flanked by a cysteine residue on each side (CX5C, CX6C, CX7C) or only on one side (CX9) of the insert. A majority of the integrin-binding sequences derived from the CX9 library contained another cysteine, indicating preferential selection of conformationally constrained cyclic peptides. Each of the four integrins studied primarily selected RGD-containing phage sequences but favored different ring sizes and different flanking residues around the RGD motif. A cyclic peptide ACRGDGWCG was synthesized based on a phage sequence that bound particularly avidly to the alpha 5 beta 1 integrin. This peptide inhibited cell attachment to fibronectin at about 5-fold lower concentrations than the most potent cyclic peptides described earlier. The most interesting structure appeared to contain two disulphide bonds. One such peptide, ACDCRGDCFCG, was synthetized and shown to be at least 20-fold more potent inhibitor of alpha v beta 5- and alpha v beta 3-mediated cell attachment to vitronectin than similar peptides with a single disulphide bond and 200-fold more potent than commonly used linear RGD peptides. These results emphasize the importance of conformational restriction as a means of improving the potency of integrin-binding peptides and point to a new way of designing effective peptides by resticting the peptide conformation with more than one cyclizing bond.

Effect of evening primrose oil (EPO) was assessed on coagulation parameters following 30 and 60 days
administration of 90, 180 and 360 μl/kg oil to healthy rabbits of either sex. There was significant increase in all
assays except Fibrinogen time. These effects might be due to inactivation or inhibition of factors affecting
coagulation. The intake of evening primrose oil also significantly decreased platelet count. Results of this study
suggest that evening primrose oil shows considerable anti-anticoagulant and anti-platelet activity in animals and
has potential to reduce cardiovascular morbidity and mortality.

SummaryCongenital afibrinogenemia (CAF) is a rare coagulation disorder characterized by very low or unmeasurable levels of functional and immunoreactive fibrinogen in plasma, associated with a hemorrhagic phenotype of variable severity. It is transmitted as an autosomal recessive trait (prevalence 1:1,000,000) and is invariantly associated with mutations affecting one of the three fibrinogen genes (FGA, FGB, and FGG, coding for Aα, Bβ, and γ chain, respectively). Fibrinogen is secreted by hepatocytes as a hexamer composed of two copies of each chain; the lack of one chain has been demonstrated to prevent its secretion. Most genetic defects causing afibrinogenemia are point mutations, where- as only three large deletions have been identified so far, all affecting the FGA gene. We here report the molecular characterization of six unrelated afibrinogenemic patients leading to the identification of eight different mutations, four hitherto unknown: a 4.1-Kb large deletion involving exon ...

Mortality due to snake envenomation is not a major problem in the United States with approximately 8–12 deaths per year, but envenomation is a serious problem that can result in functional disability, loss of extremities, and a costly recovery. Physicians encounter different clinical situations with each new snakebite victim because of the geographical variations in snake venoms. The best and most acceptable form of treatment is the use of antivenom; however, it must be administered as soon as possible since it is not so effective at reducing local signs of envenomation such as necrosis. The antivenom in the United States is in short supply, expensive and may not even be the most effective for neutralizing all North American snake venoms. In this study, we tested two antivenoms. The first was a Crotalidae Polyvalent Fab fragment with Ovine origin (FabO) manufactured in London, and the second was Antivipmyn, a Mexican manufactured antivenom that is F(ab′)2 fragment produced in horse (Fab2H). The efficacy of the two antivenoms was tested with 15 different snake venoms found in North America. Three different assays were used to test the efficacy of the antivenoms, the in vivo serum protection test (ED50), antihemorrhagic and anticoagulant. The Fab2H antivenom was most effective in neutralizing the hemorrhagic activity of 78% of the hemorrhagic venoms used in this study. In the ED50 assay, the Fab2H antivenom was effective in neutralizing all venoms used in this study, while FabO neutralized all but C. m. molossus venom. However, in most cases, FabO required less antivenom than Fab2H antivenom to neutralize three LD50.

Collagens are the most abundant components of the extracellular matrix and many types of soft tissues. Elastin is another major component of certain soft tissues, such as arterial walls and ligaments. Many other molecules, though lower in quantity, function as essential components of the extracellular matrix in soft tissues. Some of these are reviewed in this chapter. Besides their basic structure, biochemistry and physiology, their roles in disorders of soft tissues are discussed only briefly as most chapters in this volume deal with relevant individual compounds. Fibronectin with its muldomain structure plays a role of "master organizer" in matrix assembly as it forms a bridge between cell surface receptors, e.g., integrins, and compounds such collagen, proteoglycans and other focal adhesion molecules. It also plays an essential role in the assembly of fibrillin-1 into a structured network. Laminins contribute to the structure of the extracellular matrix (ECM) and modula...

D-dimer is the biochemical gold standard for diagnosing a variety of thrombotic disorders, but result reporting is heterogeneous in clinical laboratories. A specific five-item questionnaire was developed to gain a clear picture of the current standardization of D-dimer test results. The questionnaire was opened online (December 24, 2014-February 10, 2015) on the platform "Google Drive (Google Inc., Mountain View; CA)," and widely disseminated worldwide by newsletters and alerts. A total of 409 responses were obtained during the period of data capture, the largest of which were from Italy (136; 33%), Australia (55; 22%), Croatia (29; 7%), Serbia (26; 6%), and the United States (21; 5%). Most respondents belonged to laboratories in general hospitals (208; 51%), followed by laboratories in university hospitals (104; 26%), and the private sector (94; 23%). The majority of respondents (i.e., 246; 60%) indicated the use of fibrinogen equivalent unit for expressing D-dimer result...

Fibrin clot formation during normal wound healing is essential to hemostasis. Fibrin clots also serve as a scaffold for cells, such as fibroblasts, invading the wound bed. The mechanical characteristics of this fibrin – fibroblast tissue over a period of time, as the fibrin is replaced with collagen, is not well understood. In this paper, we attempt to measure specific mechanical characteristics in these systems over a period of 10 days by using fibrin – fibroblasts constructs prepared in a culture dish. We have also examined the effect of fibrinogen and thrombin concentration in the final fibrin clot on these characteristics. A well-established indentation protocol was used to determine the nominal elastic modulus of the cell-fibrin constructs at specified time points. Human fibroblast cell line CRL-2522 was used. Fibrin clots with different fibrinogen and thrombin concentration were prepared as described in Cox et al. (Tissue Engineering, Vol. 10 (5/6): 942) with cell concentration of 50,000 fibroblasts per fibrin clot. Four constructs were prepared for each of the following days 1, 5, and 10. 1 mL of a serum – containing medium was added to each well, and plates were transferred to a 5% CO2 incubator at 37 °C. On days 1, 5, and 10, the fibrin – fibroblast constructs were subject to a compressive indentation protocol. This involved applying a circular, flat-ended silica indenter to the surface of the cell/fibrin constructs through controlled displacements until reaching a specified maximum displacement, u*. An Instron 3365 Universal Testing Machine equipped with a 2.5 N load cell with a load resolution of 0.1 mN was used. Displacement rates in the range of 5–10 mm/min were used with peak displacements, u* = 0.1–5 mm. The force required to maintain these displacements was automatically recorded and analyzed for indentation stiffness over the fixed displacement range of 1.0–1.5 mm at 50 msec intervals. Our results indicate that for the unpopulated fibrin, there was a linear (R = 0.983) relationship between the indentation stiffness and fibrinogen concentration. Also, there was a nonlinear relationship between indentation stiffness and concentration of collagen in the fibrin/collagen constructs. Finally, we found in one of the cell-populated formulations a steady decrease in the indentation stiffness with increasing incubation time (1–10 days), suggesting that the cells exerted a significant effect on the construct structure and hence mechanical function.