Blood Clotting Time Research Articles

Blood biocompatibility enhancement of biomaterials by heparin immobilization: a review.

Blood contacting materials are concerned with biocompatibility including thrombus formation, decrease blood coagulation time, hematology, activation of complement system, platelet aggression. Interestingly, recent research suggests that biocompatibility is increasing by incorporating various materials including heparin using different methods. Basic of heparin including uses and complications was mentioned, in which burst release of heparin is major issue. To minimize the problem of biocompatibility and unpredictable heparin release, present review article potentially reviews the reported work and investigates the various immobilization methods of heparin onto biomaterials, such as polymers, metals, and alloys. Detailed explanation of different immobilization methods through different intermediates, activation, incubation method, plasma treatment, irradiations and other methods are also discussed, in which immobilization through intermediates is the most exploitable method. In addition to biocompatibility, other required properties of biomaterials like mechanical and corrosion resistance properties that increase by attachment of heparin are reviewed and discussed in this article.

THE STUDY OF HAEMATOLOGICAL PARAMETERS IN THE NIGERIAN LOCAL CHICKEN

An investigation was conducted to study the haematological parameters of the Nigerian local chicken using a total of 100 local chickens out of which 30 were randomly selected for bleeding. The blood samples were subjected to laboratory analysis to identify their haemoglobin contents, fragility and sedimentation rates as well as red blood cell counts, white blood cell counts and coagulation time. The results indicated that haemoglobin content ranged from 63.82 - 78.,43% with a mean of 70,43%, fragility and sedimentation rates ranged from 0.40 - 0.85% osmotic equivalent, coagulation time from 3.82 -6.25 minutes with a mean of 4.61 minutes, the red blood cell counts from 1.93 - 2.96 (x10°/ul) with a mean of 2.5 (x10°/ul) and white blood cell counts from 962 - 1,868 cells/ul with a mean of 1,216 cells/ul. It is believed that the establishment of the normal blood characteristics of the local chicken as done in this study, can be of immense aid in detecting abnormalities in the blood characteristics which can be used in diagnosing certain blood related diseases.

TOXIC EFFECTS OF THE EXTRACTS OF EUGENIA UNIFLORA LINN IN RATS

The toxic effects of the leaves of Eugenia uniflora Linn on rats was evaluated by observing abnormal changes in the haemogram including erythron and leukogram, serum biochemical parameters, histopathology, and hexobarbital sleeping time. The leaf extract produced significant increases in the packed cell volume (PCV) haemoglobin concentration and total red blood cell counts (P.05) but did not influence the blood coagulation time. Similarly the leaf extract of Eugenia uniflora produced significant increases (P.05) in the serum activities of alanine aminotransferase and aspartate aminotrasferase. Although the extract did not produce histological lesions of the liver, the increases in liver enzyme activities could be due to incipient liver damage.

Observation on the Efficacy of Autologous Blood Transfusion Combined with Controlled Hypotension in Patients with Spinal Internal Fixation during the Outbreak of New Coronavirus Pneumonia in Western Guangxi (in Guixi)

Objective: To explore the therapeutic effect of autologous blood reinfusion combined with controlled hypotension in surgical spinal fixation during the outbreak of COVID-19. Methods: 30 patients with spinal internal fixation autologous blood transfusion combined with controlled hypotension were selected as the subjects during the epidemic period from December 2019 to June 2020 in our hospital and during the operation, on the basis of routine blood pressure reduction, the American Haemonetice Corporation autologous blood continuous reinfusion system was used to infuse the blood recovered during the operation to the patient through filtration and other procedures. Results: 30 patients had no complications such as fever and hemolysis; And after the operation, the tube was dialed according to the drainage volume, the cervical thoracic and lumbar brace was customized, and the patient walked on the ground for one week; After no abnormalities, the patient was discharged. Intraoperative comparison of white blood cells (WBC), red blood cells (RBC), red blood cell pressure (HCT), hemoglobin (HGB), and coagulation time (PT) of patients with autologous blood before and after transfusion showed statistically significant differences before and after surgery (P < 0.001). Conclusion: During the new coronavirus pneumonia epidemic, the internal fixation of spinal surgery used a recovery machine to collect intraoperative blood for reinfusion. Intraoperative antihypertensive drugs were used to control blood pressure within a certain safe range. The postoperative clinical observation effect was significant and safe; especially at present the clinical significance during the epidemic was significant.

A seesaw-type device to measure the coagulation time of blood: application to assessment of anticoagulant effect of direct oral anticoagulants (DOACs) in patients

A seesaw-type device to measure the coagulation time of blood: application to assessment of anticoagulant effect of direct oral anticoagulants (DOACs) in patients

Whole blood clotting time assessment by method of laser-speckle correlation

The paper presents the results of study of the coagulation process of the whole blood with anticoagulant using the method of laser speckle correlation. The clotting time dependence curves of the correlation coefficient have been presented and discussed. Analyzing the changing trend of these curves is possible to assess the clotting time, which prove the capability of using the method of laser speckle correlation for determining the diseases of blood coagulation.

Simulated Hypergravity Activates Hemostasis in Healthy Volunteers.

BackgroundHypergravity may promote human hemostasis thereby increasing thrombotic risk. Future touristic suborbital spaceflight will expose older individuals with chronic medical conditions, who are at much higher thromboembolic risk compared with professional astronauts, to hypergravity. Therefore, we tested the impact of hypergravity on hemostasis in healthy volunteers undergoing centrifugation.Methods and ResultsWe studied 20 healthy seated men before and after 15 minutes under 3 Gz hypergravity on a long‐arm centrifuge. We obtained blood samples for hemostasis testing before, immediately after, and 30 minutes after centrifugation. Tests included viscoelastic thromboelastometry, platelet impedance aggregometry, endothelial activation markers, blood rheology testing, microparticle analyses, and clotting factor analysis. Exposure to hypergravity reduced plasma volume by 12.5% (P=0.002) and increased the red blood cell aggregation index (P<0.05). With hypergravity, thrombelastographic clotting time of native blood shortened from 719±117 seconds to 628±89 seconds (P=0.038) and platetet reactivity increased (P=0.045). Hypergravity shortened partial thromboplastin time from 28 (26–29) seconds to 25 (24–28) seconds (P<0.001) and increased the activity of coagulation factors (eg, factor VIII 117 [93–134] versus 151 [133–175] %, P<0.001). Tissue factor concentration was 188±95 pg/mL before and 298±136 pg/mL after hypergravity exposure (P=0.023). Antithrombin (P=0.005), thrombin‐antithrombin complex (P<0.001), plasmin‐alpha2‐antiplasmin complex (0.002), tissue‐plasminogen activatior (P<0.001), and plasminogen activator inhibitor‐1 (P=0.002) increased with centrifugation. Statistical adjustment for plasma volume attenuated changes in coagulation.ConclusionsHypergravity triggers low‐level hemostasis activation through endothelial cell activation, increased viscoelasticity, and augmented platelet reactivity, albeit partly counteracted through endogenous coagulation inhibitors release. Hemoconcentration may contribute to the response.

Design of a Randomized, Controlled Study to Evaluate Reversal of Anticoagulation of Ciraparantag in Healthy Adults: Whole Blood Clotting Time Assessed By Automated and Manual Methods

There is a need for safe and effective reversal agents for patients on chronic anticoagulant therapy in cases such as serious or life-threatening bleeding, urgent or emergency surgery, after major trauma, or in cases of anticoagulant overdose. Ciraparantag, an anticoagulant reversal agent in clinical development, which is believed to bind directly to anticoagulant molecules through non-covalent bonds, with no binding to blood coagulation factors or proteins in the blood. Phase 2 clinical studies have shown that ciraparantag reverses anticoagulation in healthy volunteers treated with edoxaban, enoxaparin, apixaban, or rivaroxaban as assessed by manual whole blood clotting time (WBCT). WBCT is the key pharmacodynamic marker because ciraparantag is cationic and binds to the anionic substances in standard blood collection tubes, and to anionic, colloidal activators used in the traditional coagulation assays such as PT or aPTT. Therefore, such assays are not appropriate markers for measuring ciraparantag's effect. WBCT is a direct measure of the time required for blood clot formation ex vivo and uses blood drawn into reagent-free collection equipment, using only glass as the activating agent. A Phase 2b clinical study is planned to evaluate the efficacy and safety of ciraparantag for reversal of anticoagulation as measured by WBCT using an automated point-of-care (PoC) coagulometer (developed by Perosphere Technologies, Inc.) compared with a manual testing method. This is a randomized, double-blind, placebo-controlled study in healthy adults 18 to 75 years of age who are anticoagulated with apixaban (10 mg PO twice daily) or rivaroxaban (20 mg PO once daily). Subjects who reach steady-state anticoagulation will be stratified into 2 age groups and randomized 2:1 to receive a single IV dose of ciraparantag or placebo, followed by serial WBCT testing and standard safety assessments over 24 hours. The primary efficacy endpoint is based on the extent and timing of reversal of anticoagulation following ciraparantag administration as compared with placebo, based on WBCT measured using the PoC coagulometer. Manual WBCT testing also will be performed at selected timepoints in order to describe the correlation between results obtained with the two methods. The coagulometer is expected to provide greater sensitivity and precision compared to the manual method. Further details of the design of this study will be provided. The results of this study will inform dose selection for the future Phase 3 clinical trial and will provide data on the use of the PoC coagulometer for assessment of ciraparantag for reversal of anticoagulation. Disclosures Villano: Amag Pharmaceuticals, Inc.: Consultancy. Bakhru:Pherosphere Technologies, Inc.: Current Employment. Luo:Amag Pharmaceuticals, Inc.: Current Employment. Freedman:Amag Pharmaceuticals, Inc.: Current Employment. OffLabel Disclosure: Ciraparantag is an investigational drug being evaluated for the reversal of anticoagulation induced by direct oral anticoagulant (DOAC) therapies.

Reversal of Anticoagulation By Ciraparantag: Time to Onset and Duration of Effect

Introduction: There is an unmet need for safe and effective anticoagulant reversal agents, with rapid onset of effects, for use in cases such as serious or life-threating bleeding, prior to urgent or emergency surgery, after major trauma, or in cases of anticoagulant overdose. Ciraparantag, an anticoagulant reversal agent with broad activity, binds directly to anticoagulant molecules including direct oral anticoagulants (DOACs), enoxaparin, and unfractionated heparin, without binding to endogenous coagulation factors or other plasma proteins. Two Phase 2 studies evaluated the safety and efficacy of ciraparantag for reversal of anticoagulation induced by apixaban or rivaroxaban in healthy adults. Methods: Two randomized, placebo-controlled, dose-ranging studies were conducted in healthy subjects 50-75 years of age. Subjects received apixaban or rivaroxaban until steady state. Study 1 subjects received apixaban 10 mg orally twice daily for 3.5 days. Study 2 subjects received rivaroxaban 20 mg orally once daily for 3 days. At steady-state anticoagulation subjects were randomized 3:1 to a single intravenous (IV) dose of ciraparantag (Study 1: 30, 60, or 120 mg; Study 2: 30, 60, 120 or 180 mg) or placebo. Efficacy was based on manual whole blood clotting time (WBCT) at multiple timepoints over 24 hours beginning at 15 minutes after dosing. Subjects and technicians performing the WBCT testing were blinded to treatment. WBCT measures were performed in triplicate (simultaneous testing by 3 different evaluators) at 3 separate timepoints to analyze inter-observer variability using an analysis of variance (ANOVA) model with effects for observer and subject. Results: In Study 1 (apixaban), 49 subjects were randomized to receive study drug (36 ciraparantag, 13 placebo) and completed the study as planned. In Study 2 (rivaroxaban), 64 subjects were randomized to receive study drug (48 ciraparantag, 16 placebo) and all but one subject completed the study as planned. Ciraparantag demonstrated a rapid and dose-dependent reversal of apixaban and rivaroxaban anticoagulation as measured by the proportion of subjects whose WBCT decreased to within 10% above baseline at 15 minutes after study drug infusion. A lower dose of ciraparantag was required to achieve reversal of apixaban in a large fraction of subjects compared to the dose required for reversal of rivaroxaban (Figure). Reversal of anticoagulation was sustained in these subjects throughout the 24-hour measurement period. In both studies, there was good agreement among the triplicate manual WBCT measurements; all inter-observer coefficient of variance values were &amp;lt;5%. Ciraparantag was well tolerated; the most frequent adverse events were mild, transient sensations of warmth during or soon after infusion. Conclusions: In healthy subjects at steady-state levels of anticoagulation, ciraparantag single IV doses were well tolerated and produced rapid reversal of anticoagulation in high proportions of subjects within 15 minutes of administration (the first timepoint assessed) at doses ≥60 mg for apixaban and at a dose of 180 mg for rivaroxaban which were maintained throughout the 24-hour measurement period. Figure. Proportion of subjects with WBCT reversed to within 10% above baseline at 15 minutes and 30 minutes after dosing Disclosures Ansell: Amag Pharmaceuticals, Inc.: Consultancy. Bakhru:Pherosphere Technologies, Inc.: Current Employment. Luo:Amag Pharmaceuticals, Inc.: Current Employment. Villano:Amag Pharmaceuticals, Inc.: Consultancy. OffLabel Disclosure: Ciraparantag is an investigational drug being evaluated for the reversal of anticoagulation induced by direct oral anticoagulant (DOAC) therapies.

Downregulated KLF2 in PV and ET May Induce Prothrombotic Gene Expression

Polycythemia vera (PV) and essential thrombocythemia (ET) patients have a higher risk of arterial and venous thrombosis than healthy individuals; thromboses are their principal cause of morbidity and mortality. We reported increased transcription of prothrombotic and inflammatory genes in granulocytes and platelets of PV and ET. There were differences in the expression of prothrombotic genes between platelets and granulocytes, suggesting that these cells have cell-specific contributions to thrombosis in PV and ET. Some of these prothrombotic genes are regulated by hypoxia inducible factors (HIFs) (PMID: 32203583). However, the molecular mechanism of thrombosis in PV and ET remains unknown. KLF2 (Kruppel like factor 2) is a transcription factor regulating primitive erythropoiesis and inflammation. Knockdown of KLF2 in cultured endothelial cells increases prothrombotic gene expression and reduces blood clotting time and flow rates (PMID: 15718498). Targeted deletion of KLF2 in neutrophils increases thrombosis by inducing the expression and activity of tissue factor (Blood, 2018, 132:75). To study the role of KLF2 in PV and ET thrombosis, we measured KLF2 mRNA in granulocytes from 53 PV and ET patients (25 with a history of thrombosis) and in platelets from 40 patients (21 with a history of thrombosis). We also measured KLF2 mRNA in granulocytes from 38 controls and platelets from 18 controls. Althrough the role of KLF2 in thrombosis has been studied in neutrophils, we also tested KLF2 mRNA in platelets since we previously observed a different pattern of expression of prothrombotic genes between granulocytes and platelets in PV and ET. We found lower KLF2 mRNA in both granulocytes and platelets of PV and ET patients compared to the controls (Fig. 1A and B). Compared to patients without thrombosis, those with thrombosis had lower KLF2 mRNA in platelets but not granulocytes. KLF2 mRNA in these cells correlated inversely with JAK2V617F allele burden in granulocytes (Fig. 1C and D). We then measured mRNA of prothrombotic genes: F3 (tissue factor), SELP (P-selectin), IRAK1 (interleukin 1 receptor associated kinase 1), IL1RAP (interleukin 1 receptor accessory protein), VEGFA (vascular endothelial growth factor-A), THSB1 (thrombospondin 1), SERPINE1 (encoding plasminogen activator inhibitor 1 [PAI-1]). The mRNA levels of these prothrombotic genes correlated inversely with KLF2 mRNA in platelets while SELP and THSB1 transcripts correlated inversely with KLF2 mRNA in granulocytes. KLF2 and HIFs are reported to interact (PMID: 19491109, PMID: 21565532). In order to elucidate the regulatory machanism of KLF2 in thrombosis, we measured KLF2 mRNA in patients with two inherited disorders of hypoxia sensing characterized by thrombosis: 1) Chuvash erythrocytosis (CE) due to homozygous mutation of VHLR200W (13 patients) and 2) erythrocytosis due to gain-of-function mutation of HIF-2a (two patients with HIF2AM535V and two patients HIF2AE548K). KLF2 mRNA levels did not differ in granulocytes and platelets between these patients and controls. However, two CE patients and two patients with HIF2AM535V with a history of thrombosis had lower KLF2 mRNA levels compared to patients without thrombosis (ASH this meeting, 2020 Song J). In conclusion, we report here that KLF2 transcripts are down regulated in both granulocytes and platelets from PV and ET patients and they correlate inversely with the transcripts of prothrombotic genes and JAK2V617F allelic burden, suggesting that KLF2 might be a negative regulator of thrombotic gene expression in PV and ET. Here we did not detect any changes of KLF2 transcripts in congential disorders with elevated HIFs. However, two CE patients and 2 patients with HIF2AM535V with thrombosis had less KLF2 expression compared to those without thrombosis. These results suggest that, by inference from findings in congenital disorders with elevated HIFs, KLF2 in PV and ET granulocytes and platelets may be regulated in a HIF-independent manner but that thrombosis may be regulated in a HIF-dependent manner. Thus, KLF2 may be a novel therapeutic target to prevent thrombosis in PV and ET, but confirmation by further studies is needed. The upstream regulation of KLF2 in PV and ET granulocytes and platelets needs to be elucidated. *PT &amp;JTP contributed equally Disclosures Gangaraju: Sanofi Genzyme, Consultant for Cold Agglutinin Disease: Consultancy. Gordeuk:CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Imara: Research Funding; Ironwood: Research Funding; Novartis: Consultancy.

Investigation of chitosan-g-PEG grafted nanoparticles as a half-life enhancer carrier for tissue plasminogen activator delivery.

Tissue plasminogen activator (tPA) a thrombolytic agent is commonly used for digesting the blood clot. tPA half-life is low (4-6 min) and its administration needs a prolonged continuous infusion. Improving tPA half-life could reduce enzyme dosage and enhance patient compliance. Nano-carries could be used as delivery systems for the protection of enzymes physically, enhancing half-life and increasing the stability of them. In this study, chitosan (CS) and polyethylene glycol (PEG) were used for the preparation of CS-g-PEG/tPA nanoparticles (NPs) via the ion gelation method. Particles' size and loading capacity were optimised by central composite design. Then, NPs cytotoxicity, release profile, enzyme activity and in vivo half-life and coagulation time were investigated. The results showed that NPs does not have significant cytotoxicity. Release study revealed that a burst effect happened in the first 5 min and resulted in releasing 30% of tPA. Loading tPA in NPs could decrease 25% of its activity but the half-life of it increases in comparison to free tPA in vivo. Also, blood coagulation time has significantly affected (p-value = 0.041) by encapsulated tPA in comparison to free tPA. So, CS-g-PEG/tPA could increase enzyme half-life during the time and could be used as a non-toxic candidate delivery system for tPA.

Measurement of Whole Blood Coagulation Time by Laser Speckle Pattern Correlation

We present here the results obtained by correlation analysis of digital speckle patterns to assess coagulation time in citrated whole blood. The spread of coagulation time values in experiments was no more than 25% for an essentially healthy cohort of laboratory animals. Studies of normal and pathological plasma showed that the method is able to detect pathological hemostasis. The ability to create a new universal optical coagulometer analyzing citrated and native blood, as well as whole blood, is discussed. Estimation of citrated blood clotting time is an intermediate stage in developing a test for native blood.

Preclinical evaluation of a next-generation, subcutaneously administered, coagulation factor IX variant, dalcinonacog alfa.

IntroductionThe rapid clearance of factor IX necessitates frequent intravenous administrations to achieve effective prophylaxis for patients with hemophilia B. Subcutaneous administration has historically been limited by low bioavailability and potency. Dalcinonacog alfa was developed using a rational design approach to be a subcutaneously administered, next-generation coagulation prophylactic factor IX therapy.AimThis study aimed to investigate the pharmacokinetic, pharmacodynamic, and safety profile of dalcinonacog alfa administered subcutaneously in hemophilia B dogs.MethodsTwo hemophilia B dogs received single-dose daily subcutaneous dalcinonacog alfa injections for six days. Factor IX antigen and activity, whole blood clotting time, and activated partial thromboplastin time were measured at various time points. Additionally, safety assessments for clinical adverse events and evaluations of laboratory test results were conducted.ResultsThere was an increase in plasma factor IX antigen with daily subcutaneous dalcinonacog alfa. Bioavailability of subcutaneous dalcinonacog alfa was 10.3% in hemophilia B dogs. Daily subcutaneous dosing of dalcinonacog alfa demonstrated the effects of bioavailability, time to maximal concentration, and half-life by reaching a steady-state activity sufficient to correct severe hemophilia to normal, after four days.ConclusionThe increased potency of dalcinonacog alfa facilitated the initiation and completion of the Phase 1/2 subcutaneous dosing study in individuals with hemophilia B.

Fully printed prothrombin time sensor for point-of-care testing

With an increasing number of patients relying on blood thinners to treat medical conditions, there is a rising need for rapid, low-cost, portable testing of blood coagulation time or prothrombin time (PT). Current methods for measuring PT require regular visits to outpatient clinics, which is cumbersome and time-consuming, decreasing patient quality of life. In this work, we developed a handheld point-of-care test (POCT) to measure PT using electrical transduction. Low-cost PT sensors were fully printed using an aerosol jet printer and conductive inks of Ag nanoparticles, Ag nanowires, and carbon nanotubes. Using benchtop control electronics to test this impedance-based biosensor, it was found that the capacitive nature of blood obscures the clotting response at frequencies below 10 kHz, leading to an optimized operating frequency of 15 kHz. When printed on polyimide, the PT sensor exhibited no variation in the measured clotting time, even when flexed to a 35 mm bend radius. In addition, consistent PT measurements for both chicken and human blood illustrate the versatility of these printed biosensors under disparate operating conditions, where chicken blood clots within 30 min and anticoagulated human blood clots within 20–100 s. Finally, a low-cost, handheld POCT was developed to measure PT for human blood, yielding 70% lower noise compared to measurement with a commercial potentiostat. This POCT with printed PT sensors has the potential to dramatically improve the quality of life for patients on blood thinners and, in the long term, could be incorporated into a fully flexible and wearable sensing platform.

Mikania micrantha mixed woven fabric for quick blood clotting and wound healing

The aim of this paper is to introduce novel dressing with Mikania Micrantha for quick blood clotting and wound healing. When epidermis of human skin is cut or scrapped, sometimes too much bleeding occurs. Excessive bleeding may cause death, if bleeding is not stopped immediately. To promote blood clotting &amp; wound healing natural based bio materials are still insufficient in medical textile sector. To fill up this scarcity, woven fabric treated with Mikania micrantha leaf juice &amp; leaf powder was examined. M. micrantha exhibits good blood clotting time in comparison with available dressing materials. Woven fabric (bandage) that contains M. micrantha can be used for cut wounds healing purpose. The experiments were carried out in environment friendly way which indicates the production &amp; processing of these dressing materials can have enormous contribution to sustainable operations and products.

Poor glycaemic control contributes to a shift towards prothrombotic and antifibrinolytic state in pregnant women with type 1 diabetes mellitus.

Thrombotic and antifibrinolytic influence of Diabetes mellitus type 1 (T1DM) on haemostasis have been well demonstrated. There has been no research assessing the influence of poor glycemic control on thrombus formation under flow conditions in vitro or in pregnant type 1 diabetic women to date. This study compared singleton pregnant T1DM women (n = 21) and control pregnant subjects without any metabolic disease (n = 15). The T1DM group was divided into two subgroups of sufficient (SGC-DM; HbA1c ≤6,5%,n = 15) and poor glycaemic control (PGC-DM; HbA1c >6,5%,n = 6). Evaluation of the whole blood thrombogenicity we assessed using T-TAS® at a shear rate of 240 s-1 (Total-Thrombus Analysis System, Zacros, Japan). Blood clot formation initiation time (T10) was significantly shortened in PGC-DM subgroup when compared to SGC-DM subgroup (p = 0,03). The area under the curve (AUC30) of blood clot time formation and the MPV (mean platelet volume) values were substantially higher in the PGC-DM subgroup in comparison to the SGC-DM group (p = 0,03). Negative correlations were noted between HbA1c and T10 values (p = 0,02) and between T10 and MPV values in the T1DM group (p = 0,04). Poor glycaemic control in T1DM subjects triggers a shift towards a prothrombotic and antifibrinolytic state. This phenomenon can be detected using the novel system for quantitative assessment of the platelet thrombus formation process under flow conditions in vitro. The alteration of T-TAS values in PGC-DM subgroup proves that a poor glycemic control-related shift of the equilibrium toward thrombogenesis occurs in this group of patients. Our findings need a further elucidation in research on more massive data sets to be confirmed.

Disturbance of Coagulative Hemostasis among Patients with Henoch-Schonlein Purpura

The Purpose: To examine the state of thrombocytic and coagulation hemostasis among patients withimmune microthrombovasculitis.Materials and Method: The study included 75 patients with immune microthrombovasculitis. Amongthem, rmen - 24 (32%), women - 51 (68%), the average age is 42.4±1.3 years. The control group consistedof 15 practically healthy persons.Results and Discussion: A study of coagulation hemostasis among patients with immunemicrothrombovasculitis showed the presence of hypercoagulation shift with the increase of fibrinogenconcentration, prothrombin index, shortening of the active partial thromboplastin time and blood clottingtime, the appearance of hybrid monolith complexes - level increase of D-dimer positive ethanol test.Conclusions: The most common clinical form of IMTV is the skin-joint form of the disease (62.2%),89.3% of patients were admitted with an acute form of the disease. Women get sick twice as often (67.3%)than men (32.7%), the highest incidence is in the young age group from 18 to 49 years (87.3%). There ishypercoagulability in case of immune microthrombovasculitis.

10 Efficacy and Safety of Ciraparantag in Reversing Apixaban and Rivaroxaban as Measured by Whole Blood Clotting Time in Healthy Adults

There is an unmet need for agents that can rapidly reverse the effects of the direct oral anticoagulants (DOACs) in emergency settings. Ciraparantag, an anticoagulant reversal agent with broad activity, binds directly to anticoagulant molecules including DOACs, enoxaparin and unfractionated heparin, without binding to endogenous coagulation factors or other plasma proteins. Ciraparantag has been shown to reverse anticoagulation in healthy volunteers treated with edoxaban and enoxaparin, as measured by whole blood clotting time (WBCT). Two Phase 2 studies evaluated the efficacy (measured by WBCT) and safety of ciraparantag for reversal of anticoagulation induced by apixaban or rivaroxaban in healthy adults. Two randomized, placebo-controlled, dose-ranging studies were conducted in healthy subjects 50-75 years of age. In each study, subjects received anticoagulant (apixaban or rivaroxaban) until steady state. Study 1 subjects received apixaban 10 mg orally twice daily for 3.5 days. Study 2 subjects received rivaroxaban 20 mg orally once daily for 3 days. In both studies, subjects at steady-state anticoagulation were randomized 3:1 to a single IV dose of ciraparantag (Study 1: 30, 60, or 120 mg; Study 2: 30, 60, 120 or 180 mg) or placebo. Efficacy was based on manual WBCT at multiple timepoints over 24 hours. Subjects and technicians performing the WBCT testing were blinded to treatment. In Study 1, 49 subjects were randomized to receive study drug (36 ciraparantag, 13 placebo) and completed the study as planned. In Study 2, 64 subjects were randomized to receive study drug (48 ciraparantag, 16 placebo) and all but one subject (who had an unrelated adverse event) completed the study as planned. In both studies, ciraparantag demonstrated a rapid (within 15 minutes after infusion) and dose-dependent reversal of anticoagulation compared with placebo. In both studies, analysis of least squares mean WBCT values showed statistically significant differences between each ciraparantag group and placebo. Among subjects who were anticoagulated, reversal of WBCT to ≤10% of baseline within 1 hour post-dose and sustained through at least 5 hours was observed in 67%, 100%, 100% with escalating doses of apixaban, and 17% of placebo subjects; and in 58%, 75%, 67% and 100% with escalating dose of rivaroxaban and 13% of placebo subjects. Ciraparantag was well tolerated; the most common adverse events were mild, transient sensations of warmth (typically reported as hot flashes or flushing), which were dose related. Ciraparantag, after a single IV dose, resulted in a dose-dependent reversal of the anticoagulant effect induced by steady-state dosing of apixaban or rivaroxaban in healthy subjects, as determined by manual WBCT testing. The effect was sustained through at least 5 hours after dosing, and ciraparantag was well tolerated.

28 Analytical Validation of a Novel Point-of-Care Coagulometer for DOAC and Heparin Testing

While use of the direct oral anticoagulants (DOACs) and low molecular weight heparin do not currently require routine coagulation monitoring, this can be highly desirable in at-risk patients, including those suffering major trauma or requiring emergency surgery. However, a point-of-care (PoC) device for the rapid measurement of clotting times in these patients is currently not available. The current study characterizes the performance of Perosphere Technologies’ PoC Coagulometer to DOAC- and enoxaparin-induced anticoagulation, as well as characterizes instrument precision, via a methods comparison to manual whole blood clotting time (mWBCT). For each study, whole blood samples from healthy volunteers were spiked with either 0 (sham), 30, 75, 150, 300 and 400 (apixaban, edoxaban) or 450 (rivaroxaban) ng/mL of a DOAC, or 0 (sham), 1, 2, 3, 4, and 5 μg/mL for enoxaparin, in randomized order. A single concentration was tested per day, over 6 days, and samples were tested on 5 PoC Coagulometers and by 5 operators performing mWBCT, simultaneously, for comparison. To assess the agreement of PoC Coagulometer and Manual WBCT measurements, the percent rise of clotting time using Manual WBCT was dichotomized as: 1 when %Rise <=10%, and 0 when %Rise >10%. Each of the five PoC Coagulometers used in the study was randomly paired with one of the five operators for Manual WBCT. The ROC analysis was performed for each anticoagulant using percent rise of clotting time from PoC Coagulometer against the binary status categorized by manual WBCT’s percent rise. Across all concentrations, the sensitivity of the PoC Coagulometer was significantly higher when compared to mWBCT, with absolute values of mWBCT measuring roughly twice those of the PoC Coagulometer. A strong linear correlation was observed for these methods, with R2 values of nearly 1. For individual subjects, mean baseline clotting time, and % rise of clotting time relative to baseline at the lowest and highest anticoagulant concentrations tested for each subject, for both Perosphere Technologies’ PoC Coagulometer and Manual WBCT measurements are compared in Figure 1. The sensitivity of the coagulometer proved to be roughly double that of manual WBCT across the range of concentrations tested. Similarly, the correlation coefficient of clotting time between the two methods for individual subjects yielded R >0.98, indicating a strong correlation between the two methods for individual subject for each anticoagulant. For each individual anticoagulant, the AUC of the ROC curve for coagulometer-operator pairs yielded values of 1 or close to 1 (pair 1 data are shown in Figure 1). Similarly, the other four coagulometer-operator pairs also yielded 1 or close-to-1 AUCs for each individual anticoagulant. These results indicated that the anticoagulant drug response determined by PoC WBCT agreed greatly with the anticoagulant drug response determined by manual WBCT. These results suggest that this PoC Coagulometer could be an ideal measure to assess the pharmacodynamic effects of the DOACs, delivering results within minutes, requiring only a drop of fresh whole blood.

Study of the Blood Compatibility of Sulfated Organosolv Lignins Derived from Abies sibirica and Larix sibirica Wood Pulp.

The effects of sulfated organosolv lignins derived from fir (Abies sibirica) and larch (Larix sibirica) (SLf and SLl; 4-3-7.5% sulfur, median-weight molecular mass 2960-4888 Da), on human blood/plasma clotting, platelet aggregation, and erythrocyte hemolysis were studied in vitro. Antithrombin activities of the samples were below 2 U/mg. Specimens of SLf (sulfur content 6.5, 6.6, and 7.5%, molecular weights 3503, 3487, and 3580 Da, respectively) and SLl (4.3 and 6.3%, 2960 and 3497 Da) in a concentration of 0.01 mg/ml did not prolong the blood clotting time, did not provoke human platelet aggregation, did not destroy erythrocyte membranes, and could be used for construction of drug delivery systems. The SLf sample (6.5%, sulfur, 3503 Da) in concentrations from 0.09 to 1.82 mg/ml did not stimulate platelet aggregation, reduced ADP-induced platelet aggregation, and 2-fold prolonged the blood/plasma clotting time 2-fold in comparison with control and could be used for creation of biomaterial with clot-resistant surface.