Partial Thromboplastin Time Test Research Articles

Phytochemical screening, antioxidant, anticoagulant and in vitro toxic and genotoxic properties of aerial parts extracts of Fumaria officinalis L. growing in Tunisia

Fumaria is an important plant species with many applications in herbal medicine. In this paper we report on the investigation of the phytochemical composition, antioxidant, anticoagulant and in vitro genotoxic properties of Fumaria officinalis L. which is amongst others widely used in Tunisia. Petroleum ether, ethyl acetate, chloroform and methanol extracts were made and investigated with respect to their total phenolics and flavonoids contents using standard methods. Antioxidant activity was evaluated by DPPH and ABTS methods. The anticoagulant activity was evaluated by prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests. In vitro toxic and genotoxic properties with respectively the Neutral red uptake method and the bacterial Vitotox test and comet assay in human C3A cells. This study showed that methanolic extract had the highest total phenolic and flavonoids contents. The same extract showed surprising anticoagulant and antioxidant activities. The Vitotox test revealed absence of genotoxicity for all extracts in the bacterial Vitotox test. This was confirmed in the comet assay which was conducted on human C3A cells, except for the methanolic extract where DNA damage appeared to be significantly increased at nontoxic concentrations. Thus, showing the potential of the plant as a new source of bioactive molecules for therapeutic purposes, with particular emphasis on the treatment of cardiovascular diseases.

APPJ Discharge Effects on Human Factor VIII:Ag Level in Healthy and Hemophilia A Patient

Many studies in the field of cold plasma and its application in medicine and biology have been done recently. Some of them reported that cold atmospheric pressure plasma jet (APPJ) discharge accelerates blood clotting because factor VIII (FVIII) is a plasma glycoprotein that may play a role in the coagulation cascade. In this study, we aim to assess the effect of APPJ discharge on factor VIII antigen (FVIII:Ag) in healthy and hemophilic patients. Therefore, the variations of FVIII:Ag in healthy plasma samples and hemophilic plasma samples at the times of 0, 4, 8 and 16 s treatment with APPJ were measured by ELISA technique. Additionally, activated partial thromboplastin time (APTT) test was used to check the blood coagulation rate at different treatment times. Our findings showed that the amount of FVIII:Ag in healthy samples was high to low in seconds 4 > 8 > 16 > 0. The APTT results showed that APPJ increases the blood clot formation, but in hemophilic plasma samples, APPJ reduces the clot formation speed and FVIII:Ag concentration. Accordingly, the APPJ discharge elicited a slight increase in FVIII:Ag concentration in short-term treatment, which could be involved in blood coagulation. Moreover, the effects of APPJ discharge on other coagulation factors need further studies.

Evaluation of Prothrombin time and Activated Partial Thromboplastin Time Tests in Diabetes Mellitus Patients at Meru Teaching and Referral Hospital

Evaluation of Prothrombin time and Activated Partial Thromboplastin Time Tests in Diabetes Mellitus Patients at Meru Teaching and Referral Hospital

Per oral rat treatment with glyconjugate fractions of Genipa americana leaves protects thrombus formation.

: The current study evaluated the effect of the arabinogalactan-glycoconjugate fractions (FI and FII) isolated from Genipa americana leaves given per oral in rat hemostasis protocols. Rats received daily treatment with FI or FII during 7 days and were evaluated for coagulation, platelet aggregation, venous thrombosis and bleeding tendency 1 h after the last treatment. FII prolonged in 5.5-fold the rat plasma coagulation time (activated partial thromboplastin time test). FI inhibited by 46% the platelet aggregation. Both FI and FII prevented thrombus formation by 33 and 28%, respectively. However, the bleeding time was not altered by any fractions, showing an advantage in relation to acetylsalicylic acid or warfarin that increased the bleeding time in 3.6 and 2.9-fold, respectively. Per oral treatment with the arabinogalactan-glyconjugate fractions FI and FII of G. americana leaves in rats prevents thrombus formation, being devoid of hemorrhagic risk. These results bring novel therapeutic possibilities for thromboembolic diseases.

Mixing studies for lupus anticoagulant: mostly yes, sometimes no.

Lupus anticoagulants (LAs) represent one manifestation of the clinical condition called antiphospholipid syndrome (APS) and are associated with many adverse clinical outcomes, but primarily with thrombosis and/or pregnancy morbidity. LAs are identified by laboratory testing, principally using clot-based assays based on Russell viper venom time (RVVT) and activated partial thromboplastin time (APTT) test methods. All three of the most recent guidance documents for LA testing recommend using these tests, although they vary in regard to inclusion/exclusion of other test processes. Mixing studies form part of the process of LA identification/exclusion, since in vitro LAs act like coagulation inhibitors. Mixing studies are also supported by all three LA guidance documents, but recommendations vary in regard to relative importance and placement in the LA identification/exclusion algorithm. This Point article takes the position that mixing tests are usually indicated for appropriate identification/exclusion of LAs, but can occasionally be omitted.

Anti-inflammatory and anticoagulant effects of polyphenol-rich extracts from Thymus atlanticus: An in vitro and in vivo study

Ethnopharmacological evidenceThymus atlanticus (TA) is used in traditional medicine in Morocco to treat chronic inflammatory diseases, after local and oral treatment. Aim of studyThis study aimed to investigate the in vitro and in vivo anti-inflammatory and anticoagulant activities of an aqueous extract (AE) and polyphenol fraction (PF) derived from TA. Materials and methodsThe effect of AE and PF on monocyte chemoattractant protein-1 (MCP-1) production by naïve and LPS-stimulated peritoneal macrophages isolated from C57Bl/6 mice was assessed by ELISA assay. The effect of chronic administration of the extracts at three different doses by oral rout for 2 weeks on blood coagulation and inflammation induced by carrageenan in Wistar rats was evaluated. In addition, the in vitro anticoagulant effect was tested on blood plasma collected from healthy rats using the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) tests. The acute toxicity of AE was investigated. Phytochemical analysis was carried out by HPLC. ResultsAnalysis by HPLC indicated rosmarinic acid as the main phenolic acid in TA extracts. Compared to control macrophages, MCP-1 level was lower in medium supplemented with AE at 50 and 500 μg/mL and PF at 500 μg/mL, but higher in medium with PF at 50 μg/mL. Rosmarinic and chicoric acids, served as controls, significantly decreased MCP-1 production. Chronic oral administration of TA extracts prevented inflammation induced by carrageenan and induced a significant prolongation of blood coagulation time, in a dose dependant manner, in Wistar rats. The results of the in vitro assay showed that the coagulation time was significantly prolonged in plasma incubated with extracts in APTT, PT and TT tests. Lethal dose 50 of AE in mice was 27.90 ± 1.19 g/kg. ConclusionThis study indicated TA as an herb with anti-inflammatory and anticoagulant proprieties and supports the traditional use of this plant for the treatment of inflammatory diseases.

Development of Blood Compatible Composite Using MPC Copolymer and Polyolefin for Non-PVC Blood Bag Application

Polyolefin is a good candidate for a blood bag material alternative to the poly (vinyl chloride) (PVC) blood bag that contains di-2-ethylhexyl phthalate (DEHP). However, polyolefin readily adsorbs some plasma proteins and platelets. To prevent these undesired adsorption, 2-methacryloyloxyethyl phosphorylcholine (MPC) — hydroxyethyl methacrylate (HEMA) — lauryl methacrylate (LMA) copolymers with varying monomer ratios were synthesized and used as blended material for additives to reduce platelet adsorption. Platelet adsorptive properties were reduced by blending MPC copolymers with polyolefin and confirmed by the platelet adhesion test and the activated partial thromboplastin time (APTT) test.

In Vitro Anticoagulant Activity of Mikania laevigata: Deepening the Study of the Possible Interaction Between Guaco and Anticoagulants.

Mikania laevigata, popularly known in Brazil as guaco, is widely used for respiratory disorders. As this plant is rich in coumarins, there is evidence of indications that it may cause bleeding and therefore should not be used concomitantly with anticoagulants. The basis of this information is very theoretical, with no clinical evidence of such contraindication. Thus, the aim of this study was to evaluate the in vitro effect of M. laevigata extract on blood coagulation through prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests, fibrinogen plasma concentration, and the new thrombin generation test, which investigate, with high sensibility, hemostatic changes (CAAE 60904316.6.0000.5149), besides evaluating its qualitative micromolecular composition, providing scientific evidence to support the management of patients taking warfarin. Ethanolic extracts of guaco leaves were incubated with a plasma pool of healthy individuals at concentrations of 1.67, 2.26, and 2.86 mg/mL. The presence of flavonoids, tannins, coumarins, and triterpenes was demonstrated by selective reagents in thin layer chromatography. Benzoylgrandifloric acid, cinnamoylgrandifloric acid, o-coumaric acid, coumarin, and quercetin-3-β-glucoside were identified by coinjection in ultraperformance liquid chromatography. The extract at all concentrations prolonged TP and aPPT and reduced the potential for endogenous thrombin potential by the thrombin generation test. The control plasma had endogenous thrombin potential = 1465 nM/min, and after the addition of M. laevigata extract (2.26 mg/mL), this value was reduced to 1087 nM/min, indicating a lower generation of thrombin. Related to fibrinogen plasma concentration, concentrations of 2.26 and 2.86 mg/mL were effective in reducing plasma fibrinogen levels. These results allow us to conclude that the guaco extract demonstrated an anticoagulant effect in vitro, possibly interfering with intrinsic, extrinsic, and common coagulation pathways. A discussion on the contribution of the identified substances to the activity is also present.

Use of preoperative haemostasis and ABO blood typing tests in children: a retrospective observational study using a nationwide claims database in Japan

ObjectivesTo describe the prevalence and factors associated with preoperative haemostasis and ABO blood typing tests for children because these tests might represent low-value care.DesignA retrospective observational study.SettingNationwide insurance claims database...

Anti coagulant activities of Brown Seaweed Sargassum cristaefolium Extract

Brown algae, Sargassum cristaefolium is grown abundant in Indonesia especially in South Sulawesi Province. In vitro anticoagulant effect of the extract has been shown. Therefore a study of Sargassum cristaefolium, used to inhibit blood coagulation in vivo was done. In this study, effect of flavonoid compounds from Sargassum cristaefoilum to elongate bleeding and blood clotting time and also (Prothrombin Time (PT) and Activated Thromboplastin Time (APTT) tests were carried out. Moreover, histology of mice stomach was also studied. From this study we found, that effect on bleeding time after 14 days treatment of Sargassum extract in vivo prolonged the clotting and bleeding time significantly (p < 0.05). Prothrombin time (PT) and activated partial thromboplastin time (APTT) tests on plasma confirm these research. From this study we conclude, that the flavonoid compound in Sargassum cristaefolium exhibited an anticoagulant activity.

IN VITRO ANTICOAGULANT AND ANTIOXIDANT ACTIVITIES OF PRASAPLAI RECIPE AND ZINGIBER CASSUMUNAR ROXB. EXTRACTS

Objective: This present study aimed to evaluate the anticoagulant activity and antioxidant properties of Prasaplai recipe (PPR), a Thai traditionalmedicine, and its major ingredient, Zingiber cassumunar (ZC) Roxb. extracts, seeking new therapeutic purposes for the recipe.Methods: Aqueous extracts of PPR and ZC Roxb. were prepared by hot water decoction technique. The anticoagulant activity of the extracts wasevaluated by prothrombin time (PT) and activated partial thromboplastin time (APTT) tests. In addition to anticoagulant activity, total phenolcontent and antioxidant activity were investigated. Total phenol content was determined using the Folin–Ciocalteu assay. The antioxidant activity wasestimated by DPPH radical scavenging activity and ferric reducing antioxidant power assay.Results: The APTT of plasma samples mixed with the PPR and ZC Roxb. extracts was significantly prolonged (p&lt;0.05) at the concentration of1.0 mg/ml and above comparing to the control (normal saline solution) but was no significantly different for the PT. These results suggested thatPPR and ZC Roxb. extracts showed anticoagulant activity affecting the function of coagulation factor in the intrinsic pathway. All aqueous extractspossessed considerable antioxidant activity and were rich in total polyphenol.Conclusion: This finding indicates that the aqueous extracts possess significant anticoagulant and antioxidant activities, thus showing the potentialPPR and ZC Roxb. as a new source of bioactive compounds for therapeutic purposes, with particular emphasis on the prevention and treatment ofthrombosis.

Haemostatic properties of Vernonia amygdalina and Chromolaena odorata leaf extracts using Wistar rat model

BACKGROUNDThe leaves of African plants are widely employed in Nigeria to control bleeding from wounds. This work is aimed at evaluating the haemostatic effects of Vernonia amygdalina (VA/bitter leaf) and Chromolaena odorata (CO/sunflower) leaves on some haemostatic parameters.METHODSA laboratory study of experimental design was conducted involving 35 Wistar rats that were randomized into seven groups. Groups 1 and 2 received leaf extracts of VA at concentrations of 150 and 250mg/kg BW, respectively; groups 3 and 4 received leaf extracts of CO at 150 and 250mg/kg BW; groups 5 and 6 received combined leaf extracts of VA and CO at 150 and 250mg/kg BW, respectively, for 30 days. The last group 7 as control group received only water. Parameters investigated were clotting time (CT), fibrinogen concentration, prothrombin time (PT), activated partial thromboplastin time test (APTT), factor VII, protein C and D – dimer.ResultsThere was a significant reduction in CT, fibrinogen concentration and PT in the intervention groups compared to controls (p&lt;0.01). There was no significant difference in APTT, factor VII and protein C in the intervention groups compared to the controls (p&gt;0.05). D-dimer levels were observed to increase significantly in rats treated with 150mg/kg BW of VA and 150mg/kgBW of the combined leaf extracts (VA/CO) compared to the controls (p&lt;0.05).ConclusionThe VA and CO extracts reduced CT, PT, fibrinogen concentrations and increased D-dimer levels in rats. This study suggests the possible incorporation of the leave extracts of VA and CO in bleeding diathesis as well as in coagulation studies.

Photodynamic Therapy of Ovarian Carcinoma Cells with Curcumin-Loaded Biodegradable Polymeric Nanoparticles.

Accumulation of photosensitisers in photodynamic therapy in healthy tissues is often the cause of unwanted side effects. Using nanoparticles, improved bioavailability and site-specific drug uptake can be achieved. In this study, curcumin, a natural product with anticancer properties, albeit with poor aqueous solubility, was encapsulated in biodegradable polymeric poly(lactic-co-glycolic acid) (PLGA) nanoparticles (CUR-NP). Dynamic light scattering, laser Doppler anemometry and atomic force microscopy were used to characterise the formulations. Using haemolysis, serum stability and activated partial thromboplastin time tests, the biocompatibility of CUR-NP was assessed. Particle uptake and accumulation were determined by confocal laser scanning microscopy. Therapeutic efficacy of the formulation was tested in SK-OV-3 human ovarian adenocarcinoma cells post low level LED irradiation by determining the generation of reactive oxygen species and cytotoxicity. Pharmacologic inhibitors of cellular uptake pathways were used to identify the particle uptake mechanism. CUR-NP exhibited better physicochemical properties such as stability in the presence of light and improved serum stability compared to free curcumin. In addition, the novel nanoformulation facilitated the use of higher amounts of curcumin and showed strong apoptotic effects on tumour cells.

Croatian Society of Medical Biochemistry and Laboratory Medicine: National recommendations for blood collection, processing, performance and reporting of results for coagulation screening assays prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen and D-dimer.

A modern diagnostic laboratory offers wide spectrum of coagulation assays utilized in the diagnosis and management of patients with haemostatic disorders, preoperative screening and anticoagulation therapy monitoring. The recent survey conducted among Croatian medical biochemistry and transfusion laboratories showed the existence of different practice policies in particular phases of laboratory process during coagulation testing and highlighted areas that need improvement. Lack of assay standardization together with non-harmonized test results between different measurement methods, can potentially lead to incorrect decisions in patient’s treatment. Consequently, patient safety could be compromised. Therefore, recommended procedures related to preanalytical, analytical and postanalytical phases of prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen and D-dimer testing are provided in this review, aiming to help laboratories to generate accurate and reliable test results.

In Vitro Antiatherothrombotic Effects of Extracts from Berberis Vulgaris L., Teucrium Polium L., and Orthosiphon Stamineus Benth.

Coronary artery disease is the leading cause of mortality and morbidity worldwide. The pathogenesis is mainly due to atherosclerosis, plaque rupture, and platelet thrombus formation. The main risk factors for coronary artery disease include obesity, hypercholesterolemia, smoking, diabetes, and high blood pressure. As a part of disease management, treatment options using anticoagulant and antiplatelet drugs can be applied with addition to lipid-lowering medication. However, medicinal plants comprising antiatherothrombotic effects can be used as options to combat the disease rather than drug therapies with lesser adverse effects. Therefore, the haematological effect of Berberis vulgaris L., Teucrium polium L., and Orthosiphon stamineus Benth extracts was studied using in vitro model to prevent and to treat coronary atherothrombotic disease. The aqueous, methanol, and polysaccharide extracts of B. vulgaris, T. polium, and O. stamineus, respectively, were studied for their anticoagulant and antiplatelet effect on human whole blood. Extracts were subjected to the prothrombin time (PT) and activated partial thromboplastin time (APTT) test for anticoagulant activity. The antiplatelet activity was investigated using an electrical impedance method. B. vulgaris aqueous extract (BVAE), B. vulgaris polysaccharide extract (BVPE), T. polium aqueous extract (TPAE), and T. polium polysaccharide extract (TPPE) significantly prolonged the coagulation time in a concentration-dependent manner (p<0.05). The administration of BVAE demonstrated the most effective antiplatelet activity against platelet aggregation caused by arachidonic acid (AA) and collagen. These antiplatelet activities may correspond to the presence of higher total phenolic compound, which thus inhibit the platelet aggregation activity. In conclusion, these findings provide strong evidence on the antiatherothrombotic effect of BVAE and TPAE.

Hemocompatibility assay of a micro-catheter using hydrophilic coating biomaterials.

For medical devices directly or indirectly contacted with blood, hemocompatibility assay is of great importance during the biological evaluation. In ISO 10993-4:2017 - Biological evaluation of medical devices part 4, a selection of tests for interactions with blood is given with the rationale for selection of tests based on their intended use specified, however, the specific testing protocols may vary significantly when performing the hemocompatibility assays. In recent years, medical catheters have been widely used in clinical practice. Moreover, a lot of surface modified catheters emerged in the market to enhance their performance of hemocompatibility especially for hydrophilic coating catheters. Unfortunately, to date, the hemocompatibility of hydrophilic coating still remains controversial due to the inherent complexity of the hemocompatibility test itself and lack of validated test methods. In this study, through determining the hemocompatibility performance for a micro-catheter with a typical hydrophilic pyrrolidone coating regarding haemolysis test, partial thromboplastin time (PTT), prothrombin time (PT) and thrombogenicity test in dogs, we have established a series of tentative hemocompatibility protocols for these tests. Hopefully, our study could not only provide some useful information for hemocompatibility evaluation on medical catheters with a hydrophilic coating but could also contribute to the development of neo-type hemocompatible medical devices for better clinical practice.

How to Optimize Activated Partial Thromboplastin Time (APTT) Testing: Solutions to Establishing and Verifying Normal Reference Intervals and Assessing APTT Reagents for Sensitivity to Heparin, Lupus Anticoagulant, and Clotting Factors.

The activated partial thromboplastin time (APTT) assay is a very common coagulation test, used for several reasons. The test is conventionally used for assessing the contact factor (intrinsic) pathway of blood coagulation, and thus for screening deficiencies in this pathway, most typically factors VIII, IX, and XI. The APTT is also sensitive to contact factor deficiencies, including factor XII, prekallikrein, and high-molecular-weight kininogen. The APTT may also be elevated in a variety of conditions, including liver disease, vitamin K deficiency, and disseminated intravascular coagulation. The APTT can also be used for monitoring unfractionated heparin (UFH) therapy, as well as for screening lupus anticoagulant (LA) or for assessing thrombosis risk. Which of these separate uses is important to a given laboratory or clinician depends on the laboratory and the clinical context. For example, UFH sensitivity is important in hospital-based laboratories, where UFH therapy is used, but not in hospital-based laboratories where low-molecular-weight heparin (LMWH) is largely employed or where UFH may be assessed by anti-factor Xa testing, or in private/community laboratories not associated with a hospital system. High sensitivity to (low levels of) factors VIII, IX, and XI is generally preferred, as their deficiencies are clinically significant. Also preferred, but not usually achieved, is low sensitivity to factor XII and other contact factors, as these deficiencies are usually asymptomatic. Nevertheless, a good knowledge of factor sensitivity is usually needed, if only to help explain the reasons for a prolonged APTT in a given patient, or whether factor testing or other investigation is required. A good working knowledge of reagents sensitivity to LA is also advisable, especially when the reagent is used as part of a LA test panel, or else as a "general-purpose screening reagent." The current report is aimed at providing some guidance around these questions, and is intended as a kind of "how to" guide, that will enable laboratories to assess APTT reagents in regard to their sensitivity to heparin, LA, and clotting factors. The report also provides some advice on generation of normal reference ranges, as well as solutions for troubleshooting prolonged APTTs, when performing factor testing or searching for inhibitors.

Factor Xa Inhibitory Profile of Apixaban, Betrixaban, Edoxaban, and Rivaroxaban Does Not Fully Reflect Their Biologic Spectrum.

The currently available oral anti-Xa agents are claimed to produce their anticoagulant and antithrombotic effects solely by the inhibition of factor Xa. This study profiled various anti-Xa drugs in routinely used laboratory assays to demonstrate that their effects are not solely related to the anti-Xa activities. Apixaban, betrixaban, edoxaban, and rivaroxaban were obtained commercially. Native and citrated whole blood was used for the activated clotting time (ACT) and thromboelastography (TEG). Citrated plasma was used for monitoring the prothrombin time (PT), activated partial thromboplastin time (aPTT), Heptest, and prothrombinase-induced clotting time (PiCT) tests. An amidolytic method was used for the determination of anti-Xa effects. Thrombin-induced fibrinokinetics was monitored optically. Thrombin generation studies were carried out using the calibrated automated thrombogram. All of the anti-Xa agents produced concentration- and assay-dependent effects. In the ACT at 2.5 μg/mL and TEG at 1.0 μg/mL, edoxaban exhibited the strongest anticoagulation effect. In the PiCT, PT, and aPTT assay at 1 μg/mL, edoxaban showed stronger effects than other agents. The half maximal inhibitory concentration of these agents for the inhibition of factor Xa ranged from 340 to >1000 ng/mL. In the thrombin generation inhibition assay, apixaban showed the strongest activity. In the fibrinokinetics, different anti-Xa agents produced varying degrees of inhibition. These results demonstrate that the measured anti-Xa activity alone does not fully reflect the overall biologic spectrum of these agents.

Anti-Thrombin, Anti-Adhesive, Anti-Migratory, and Anti-Proliferative Activities of Sulfated Galactans from the Tropical Green Seaweed, Udotea flabellum.

In this study, sulfated polysaccharide-rich extracts were isolated from 22 tropical seaweeds (4 red, 11 brown, and 7 green) found in northeastern Brazil, and evaluated for the role of anticoagulant agents. Fifteen of the extracts showed anticoagulant activity, including all the extracts from green seaweeds. Udotea flabellum (a green seaweed) extract was the most potent, requiring an amount of only 3 µg to double the plasma coagulation time in the activated partial thromboplastin time test. A similar result was obtained with 1 µg of heparin. Two sulfated homogalactans with anticoagulant activity, F-I (130 kDa) and F-II (75 kDa), were isolated from this extract using several bio-guided purification steps. Their anticoagulant activity, as well as properties related to antitumor activity (anti-proliferative, anti-adhesive, and anti-migratory), were accessed. Their anticoagulant activities were close to that of heparin. We found that F-I and F-II (0.5–10 μg/mL) were not able to directly inhibit thrombin. In the presence of anti-thrombin, F-I (0.5 μg/mL) was more effective than heparin (0.5 μg/mL) in inhibiting thrombin, while F-II showed similar effects as heparin. F-I and F-II also inhibited B16-F10 (murine melanoma cells) adhesion, migration, and proliferation on a fibronectin-coated surface, but not on laminin- or collagen I-coated surfaces. Except for the antiproliferative activity, the other effects of F-I and F-II were eliminated upon their desulfation (~50%), indicating that the degree of sulfation is not as important for F-I and F-II anti-proliferative activity as the sulfation position. Taken together, the results provide strong evidence for the potential utility of sulfated galactans from U. flabellum, making these compounds an interesting option for future investigations that aim to design new anticoagulant/antitumor agents.

Aggregating resistant Staphylococcus aureus induces hypocoagulability, hyperfibrinolysis, phagocytosis, and neutrophil, monocyte, and lymphocyte binding in canine whole blood.

Staphylococcus aureus is an opportunistic pathogen with the ability to form mobile planktonic aggregates during growth, in vitro. The in vivo pathophysiologic effects of Saureus aggregates on host responses are unknown. Knowledge of these could aid in combating infections. This study aimed to investigate the effect of increasing concentrations of two different aggregating Saureus strains on the hemostatic and inflammatory host responses in canine whole blood. The hypothesis was that aggregating bacteria would induce pronounced hemostatic and inflammatory responses. Citrate-stabilized whole blood from 10 healthy dogs was incubated with two strains of aggregating Saureus at three different concentrations. Each sample was analyzed using tissue factor-thromboelastography (TF-TEG) and the formed clot was investigated with electron microscopy. The plasma activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, and D-dimer tests were measured. Bacteria-leukocyte binding was evaluated with flow cytometry, and neutrophil phagocytosis was assessed using light and transmission electron microscopy. The highest concentration of bacteria resulted in a significantly shortened TF-TEG initiation time, decreased alpha, maximum amplitude, global strength, and increased lysis. In addition, significantly shortened PT, decreased fibrinogen, and increased D-dimers were demonstrated at the highest concentration of bacteria. Lower concentrations of bacteria showed no differences in TF-TEG when compared with controls. The findings were similar for both Saureus strains. Increased concentration-dependent binding of bacteria and leukocytes and neutrophil bacterial phagocytosis was observed. Two strains of Saureus induced alterations of clot formation in concentrations where bacterial aggregates were formed. A concentration-dependent cellular inflammatory response was observed.