Heparin Concentration Research Articles

Sensitivity improved with Parylene-C passivized on Lamb wave sensor for aPTT measurement through monitoring whole blood reaction

Blood clotting time monitoring is of great importance in predicting the risk of haemorrhage and cardiovascular diseases. In this study, a new P-Lamb wave sensor was developed to measure activated partial thromboplastic time (aPTT) with enhanced sensitivity. The sensor utilizes a piezoelectric and hydrophobic material, Parylene-C, as a waveguide for the P-Lamb wave sensor in order to monitor the aPTT in whole blood samples. With a smooth surface, the P-Lamb wave sensor reduced energy loss and prevented leaky modes, with a decrease of 33% ± 1.25% in the surface roughness and an increase of 2.75% ± 0.15% in the signal. The experimental results demonstrated that, compared to a quartz crystal microbalance (QCM), a P-Lamb sensor with high sensitivity (the frequency shift of a P-Lamb sensor is approximately 200 times greater than that of a QCM) improved stability and enhanced repeatability. Parylene-C worked as a phonon coupling layer, which improved the stability and sensitivity of the Lamb sensor. The relative standards deviation (RSD) of the aPTT measurement was 2.11%, which was 1.22 times lower than reported values. The P-Lamb wave sensor was also tested for its sensitivity to different concentrations of heparin and was found to exhibit an increase in coagulation time with an increasing heparin concentration. Compared to the SYSMEX CS 5100 haematology analyser, the clinical coefficient index (R2) was 0.99467. Considering its compact size, low cost, and mass production of the chip unit, the developed P-Lamb wave sensor is a promising device for point-of-care diagnosis of haemostasis and personal health monitoring.

Characterization of a novel protein of Leptospira interrogans exhibiting plasminogen, vitronectin and complement binding properties

Leptospirosis is a severe zoonosis caused by pathogenic species of the genus Leptospira. This work focuses on a hypothetical protein of unknown function, encoded by the gene LIC13259, and predicted to be a surface protein, widely distributed among pathogenic leptospiral strain. The gene was amplified from L. interrogans serovar Copenhageni, strain Fiocruz L1-130, cloned and the protein expressed using Escherichia coli as a host system. Immunofluorescence assay showed that the protein is surface-exposed. The recombinant protein LIC13259 (rLIC13259) has the ability to interact with the extracellular matrix (ECM) laminin, in a dose-dependent manner but saturation was not reach. The rLIC13259 protein is a plasminogen (PLG)-binding protein, generating plasmin, in the presence of urokinase PLG-activator uPA. The recombinant protein is able to mediate the binding to human purified terminal complement route vitronectin, C7, C8 and C9, and to recruit and interact with these components from normal human serum (NHS). These interactions are dose-dependent on NHS increased concentration. The binding of rLIC13259 to C8 and vitronectin was slight and pronounced inhibited in the presence of increasing heparin concentration, respectively, suggesting that the interaction with vitronectin occurs via heparin domain. Most interesting, the interaction of rLIC13259 with C9 protein was capable of preventing C9 polymerization, suggesting that the membrane attack complex (MAC) formation was inhibited. Thus, we tentatively assign the coding sequence (CDS) LIC13259, previously annotated as unknown function, as a novel protein that may play an important role in the host’s invasion and immune evasion processes, contributing to the establishment of the leptospiral infection.

A cellulose-based photoacoustic sensor to measure heparin concentration and activity in human blood samples

Heparin is an indispensable drug in anticoagulation therapy but with a narrow therapeutic window, which dictates regular testing and dose adjustment. However, current monitoring tools have a long turnaround time or are operator intensive. In this work, we describe a cellulose-based photoacoustic sensor for heparin. The sensors have a turnaround time of 6 min for whole blood samples and 3 min for plasma samples regardless of heparin concentration. These sensors have a limit of detection of 0.28 U/ml heparin in human plasma and 0.29 U/ml in whole blood with a linear response (Pearson's r = 0.99) from 0 to 2 U/ml heparin in plasma and blood samples. The relative standard deviation was < 12.5% in plasma and < 17.5% in whole blood. This approach was validated with heparin-spiked whole human blood and had a linear correlation with the activated partial thromboplastin time (aPTT) (r = 0.99). We then studied 16 sets of clinical samples—these had a linear correlation with the activated clotting time (ACT) (Pearson's r = 0.86, P < 0.0001). The photoacoustic signal was also validated against the cumulative heparin dose (Pearson's r = 0.71, P < 0.0001). This approach could have applications in bed-side heparin assays for continuous heparin monitoring.

Is There an Alternative to Serotonin Release Assay for the Diagnosis of Heparin Induced Thrombocytopenia (HIT)? Evaluation of 5 Other Functional Methods Using 5B9 a Monoclonal IgG That Mimics HIT Human Antibodies

Introduction: Serotonin Release Assay (SRA) is today considered as the “gold standard” to detect pathogenic Heparin-Induced Thrombocytopenia (HIT) antibodies. However, this method is time-consuming, expensive and necessitates the use of 14C-radio-labelled serotonin, this implicating a specific agreement and secured premises, with a non-negligible environmental impact. These limitations explain that the use of SRA is restricted to a few laboratories worldwide. Finding a more accessible method with similar performances is therefore a challenge, and other different functional assays, such as Heparin-Induced Multiple Electrode Aggregometry (HIMEA), Light Transmission Aggregometry (LTA) using platelet rich plasma (PRP) or washed platelet (WP), ATP release, and Flow Cytometry (FC), are available. However, the sensitivity of these assays has never been comparatively evaluated with a standardized reagent.Objectives:The objective of our study was therefore to evaluate the sensitivity of these 5 functional methods for the detection of HIT antibodies in comparison with SRA, using 5B9, a monoclonal chimeric anti-PF4/H IgG recently developed in our laboratory, which fully mimics the effects of human HIT antibodies (Kizlik-Masson et al, J Thromb Haemost, 2017).Material and Methods: Platelet activation induced by 5B9 with heparin was assessed by the 6 following methods with blood samples from 10 consecutive unselected healthy donors:•HIMEA performed with whole blood (Multiplate Analyzer® Roche),•LTA performed with PRP (Chronolog®, Chrono-Log corporation),•FC based on the assessment of P-selectin expression and performed with PRP (HIT Confirm®, Emosis on AccuriC6 plus®, Becton Dickinson),•ATP release performed with WP (Chronolog®, Chrono-Log corporation),•LTA performed with WP (Chronolog®, Chrono-Log corporation),•SRA performed with WP (LSC scintillation counter, Perkin Elmer).For each method, different concentrations of 5B9 (10-20-50 µg/mL) were tested without heparin, and with “therapeutic” or high concentrations of unfractionated heparin (ranging from 0.1 to 1 and from 10 to 200 IU/mL respectively, according to the functional assay performed). The 3 concentrations of 5B9 were previously defined as “low” (10 µg/mL inducing in most cases a serotonin release <50% and no platelet aggregation in PRP), “high” (50 µg/mL always inducing a serotonin release >50% and platelet aggregation in PRP) or “intermediate” (20 µg/mL yielding variable results).Results: With the highest concentration of 5B9 (50 µg/mL), a strong platelet activation was detected with all methods and donors tested. HIMEA exhibited similar sensitivity (Ss 100%) than SRA to detect the activation induced by 20 μg/mL 5B9. FC was also able to detect the effect induced by 20 μg/mL 5B9 with 9/10 donors tested (90%). Alternatively, the measurement of ATP release, and LTA performed with WP or PRP failed to detect the effect of 20 μg/mL 5B9 in 30, 30 and 40 % of donors tested, respectively. SRA was the only method able to detect platelet activation induced by 10 μg/mL 5B9 with all donors tested, and the other methods were less sensitive (table). LTA performed with PRP was always negative (Ss= 0%). Platelet washings increased LTA sensitivity for detecting 10 or 20 μg/mL 5B9 (40% and 70% with WP vs. 0 and 60% with PRP, respectively), and the measurement of ATP release exhibited similar sensitivity. When platelet activation was evaluated in whole blood by HIMEA or in PRP using FC, the sensitivity to detect HIT antibodies was also improved (60% and 50%, respectively).Conclusion: These results confirm that SRA is likely the more sensitive functional assay to detect low concentrations of HIT antibodies. Indeed, apart from SRA, none of the other methods was able to detect the lowest concentration of 5B9 with 100% of donors. Interestingly, FC or HIMEA, which are rapid assays, also exhibit a high sensitivity, close to 100%, for detecting “intermediate” concentrations of HIT antibodies (i.e. corresponding to 20 μg/mL 5B9). We will further study the performances of these functional tests, including their specificity, by assessing patient's samples with confirmed HIT or having developed non-pathogenic antibodies (study in progress). [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Evaluating the effects of anticoagulants on Rhodnius prolixus artificial blood feeding.

Blood-sucking insects are responsible for the transmission of several important disease-causing organisms such as viruses, bacteria, and protozoans. The hematophagous hemipteran Rhodnius prolixus is one of the most important vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Due to the medical importance of this insect, it has been used as a study model in physiology and biochemistry since the 1930s. Artificial feeding has been recognized as a feasible and a more ethical alternative method of feeding these hematophagous insects. To prevent clotting after blood collection defibrination or treatment with anticoagulants are necessary. Although anticoagulants have been routinely used for stabilizing the collected blood, there is a gap in demonstration of the effects of using anticoagulants on the feeding and development of the hematophagous insect Rhodnius prolixus. In this study, we compared the survival rate, molting efficiency, fertility, and infection development between insects that were fed on blood containing three different anticoagulants (citrate, EDTA, and heparin). We observed that fifth instar nymphs that were fed on blood containing EDTA and citrate could not perform digestion properly, which resulted in molting inefficiency. Adult insects that were fed on EDTA-containing blood laid lower number of eggs, and also had a diminished egg hatch percentage. When we delivered T. cruzi parasites in blood containing citrate or EDTA to the insects, a lower number of parasites and metacyclic trypomastigotes was observed in the intestine compared to the group fed on heparin-containing blood. Since heparin could potentially inhibit DNA polymerase activity in DNA samples extracted from the intestine, we analyzed different heparin concentrations to determine which one is the best for use as an anticoagulant. Concentrations ranging between 2.5 and 5 U/mL were able to inhibit coagulation without severely impairing DNA polymerase activity, thus indicating that this should be considered as the range of use for feeding experiments. Our results suggest that among the three anticoagulants tested, heparin can be recommended as the anticoagulant of choice for R. prolixus feeding experiments.

Comparing a New Bovine Source Heparin to the Clinically Used Porcine Heparin for Platelet Function Effects and Heparin-Induced Thrombocytopenia Potential

BackgroundHeparin is a sulfated polysaccharide obtained from intestinal mucosa with anticoagulant properties that is widely used as a standard clinical therapeutic agent to treat and prevent thrombosis. Heparin is known to affect platelet function, and among its side effects is heparin-induced thrombocytopenia (HIT) that can occur in about 1% of patients exposed to heparin. Presently, only porcine source heparin is approved for use in the United States. The aims of this study were to determine if platelet activation by physiological agonists and platelet aggregation induced by HIT antibodies would be equivalent in the presence of bovine source heparin and porcine source heparin.Materials and MethodsSeven lots of bovine heparin from Eurofarma and 3 lots of commercial clinical grade porcine heparin (Pfizer/Hospira) were evaluated. The USP Reference Standard for porcine heparin was used to determine anti-Xa and anti-IIa potencies of the bovine heparins. For each study, blood was collected from healthy volunteers (n=5 per test group), anticoagulated with sodium citrate, and centrifuged to obtain platelet rich plasma (PRP). Platelet aggregation responses were assessed using the BioData PAP-8 platelet aggregometer. For the first aim to evaluate platelet function, PRP was combined with heparin at final concentrations of 10.0, 1.0, and 0.1 µg/mL, covering both therapeutic and prophylactic ranges. Platelet agonists included adenosine diphosphate (ADP), collagen, epinephrine, arachidonic acid, and thrombin receptor agonist peptide (TRAP). The aggregation response was quantitated in terms of primary slope (PS), area under the curve (AUC), maximum aggregation (MA), and final aggregation (FA). For the second aim to evaluate the HIT potential, antibodies to the complex of heparin-platelet factor 4 (H-PF4) from banked HIT patient apheresis fluid were combined with donor PRP and heparin. Heparins were tested at final concentrations of 0.1, 0.4, 0.8, 1, and 100 U/mL. PS and FA results were recorded. For all data, comparisons were analyzed with 2-Way ANOVA using SigmaPlot software.ResultsIn the presence of either bovine (BMH) or porcine heparin (PMH), the normal platelet aggregation response of all donors was not altered from that obtained with saline (see representative aggregation tracing in the image below). All heparin concentrations produced the same response. There were no significant differences between the bovine and porcine heparins for each of the 4 platelet aggregation parameters for ADP, arachidonic acid, collagen, epinephrine, and TRAP. Variation in the PS for arachidonic acid and collagen need to be assessed in a larger pool of donors to assure the lack of significant difference. Platelet activation to H-PF4 antibodies was strong at 0.1 to 1 U/mL concentrations with the expected inhibition observed when using 100 U/mL heparin. The HIT potential between bovine heparin and porcine heparin demonstrated no significant difference between the heparins (see MA responses in the image below). There were no lot to lot differences for the bovine heparins or the porcine heparins in either the platelet aggregation studies or the assessment for HIT.ConclusionIn these studies of platelet function, the bovine and porcine source heparins were comparable with regards to their effects on platelet aggregation induced by multiple different agonists and their HIT potential. [Display omitted] DisclosuresWalenga:Eurofarma: Research Funding.

Stability of Meropenem and Piperacillin/Tazobactam with Heparin in Various Peritoneal Dialysis Solutions.

Infections caused by ceftazidime-resistant Pseudomonas and extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacteria are increasing worldwide. Meropenem and piperacillin/tazobactam (PIP/TZB) are recommended for the treatment of peritoneal dialysis-associated peritonitis (PDAP) caused by ceftazidime-resistant Pseudomonas and other resistant gram-negative bacteria. Patients may also receive intraperitoneal heparin to prevent occlusion of their catheters. However, the stability of meropenem or PIP/TZB, in combination with heparin, in different types of peritoneal dialysis (PD) solutions used in clinical practice is currently unknown. Therefore, we investigated the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. A total of 15 PD bags (3 bags for each type of PD solution) containing meropenem and heparin and 24 PD bags (3 bags for each type of PD solution) containing PIP/TZB and heparin were prepared and stored at 4°C for 168 hours. The same bags were stored at 25°C for 3 hours followed by 10 hours at 37°C. An aliquot withdrawn before storage and at defined time points was analyzed for the concentration of meropenem, PIP, TZB, and heparin using high-performance liquid chromatography. Samples were also analysed for particle content, pH and color change, and the anticoagulant activity of heparin. Meropenem and heparin retained more than 90% of their initial concentration in 4 out of 5 types of PD solutions when stored at 4°C for 168 hours, followed by storage at 25°C for 3 hours and then at 37°C for 10 hours. Piperacillin/tazobactam and heparin were found to be stable in all 8 types of PD solutions when stored under the same conditions. Heparin retained more than 98% of its initial anticoagulant activity throughout the study period. No evidence of particle formation, color change, or pH change was observed at any time under the storage conditions employed in the study. This study provides clinically important information on the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. The use of meropenem-heparin admixed in pH-neutral PD solutions for the treatment of PDAP should be avoided, given the observed suboptimal stability of meropenem.

Оптимизация первой стадии синтеза эноксапарина методом гидролитической деполимеризации нефракционированного гепарина

Исследована первая стадия получения низкомолекулярного гепарина (эноксапарина) методом гидролитической деполимеризации нефракционированного гепарина, которая заключается в химическом взаимодействии исходного гепарина с хлоридом бензетония в водно-солевых (NaCl) растворах. Показано, что с повышением концентрации хлорида натрия у нефракционированного гепарина определяется большее количество кислотных эквивалентов. Вероятно, это связано с влиянием ионной силы раствора на конформацию макромолекулы гепарина, что подтверждается данными метода динамического рассеяния света. Средний размер наблюдаемых центров светорассеяния в водных растворах гепарина падает с увеличением концентрации хлорида натрия. Показано, что для ускорения очистки гепарината бензетония от исходных реагентов, а также для снижения количества промывных вод целесообразно применять промывание водой, а не растворами хлорида натрия, а также использовать ультразвуковую обработку. Состав полученных и очищенных образцов гепарината бензетония подтвержден методом 1H ЯМР.

Histone-Mimetic Gold Nanoparticles as Versatile Scaffolds for Gene Transfer and Chromatin Analysis.

Histone-inspired polymer assemblies (polyplexes) can regulate gene expression and subcellular transport in plasmids by harnessing the cellular machinery normally used for histone proteins. When grafted to polyplexes, histone tails promote nuclear accumulation, trigger plasmid DNA (pDNA) release, and enhance transcription. Herein, we developed multifunctional gold nanoparticles (AuNPs) decorated by histone motifs as histone-inspired scaffolds with improved pDNA binding, easy bioimaging, and increased potential for gene delivery and chromatin analysis applications. We hypothesized that polycationic AuNPs coupled to histone motifs would mimic the native presentation of these sequences on the histone octamer and thereby create structures with the capacity to both engage native histone effectors and condense pDNA into nucleosome-inspired nanostructures. AuNPs bearing ∼2 nm cores were prepared based on the well-established Brust-Schiffrin two-phase method involving tetrachloroaurate reduction in the presence of 1-pentanethiol. Solid phase peptide synthesis was employed to generate thiolated polycationic ligands and histone tail motifs, and the AuNPs and peptide ligands were combined in a two-step Murray place exchange reaction at various ratios to produce a collection of polycationic AuNPs modified with varying amounts of histone tails. Electron microscopy and thermal analyses demonstrated that these modified AuNPs exhibited tunable biochemical and biophysical properties that closely mimicked the properties of native histones. The histone-mimetic nanoscaffolds efficiently and sequence-specifically engaged histone effectors responsible for activating transcription. In addition, the nanoscaffolds condensed pDNA into complexes with high stability in the presence of physiological concentrations of heparin, a common extracellular polyanion. These combined properties of histone engagement and high stability led to a ∼6-fold enhancement in transfection efficiency as compared with typical polymeric transfection reagents, with the increased transfection efficiency correlated to the presence and amount of histone tails displayed on the surface of the nanoscaffolds. These findings demonstrate the utility of employing a biomimetic materials design approach to develop more effective and stable delivery vehicles for gene transfer and chromatin analysis applications.

Heparin–protamine balance after neonatal cardiopulmonary bypass surgery

Background Neonates undergoing cardiopulmonary bypass (CPB) are at risk of excessive bleeding. Blood is anticoagulated with heparin during CPB. Heparin activity is reversed with protamine at the end of CPB. Paradoxically, protamine also inhibits blood coagulation when it is dosed in excess of heparin. Objectives To evaluate heparin-protamine balance in neonates undergoing CPB by using research and clinical assays, and to determine its association with postoperative bleeding. Patients/Methods Neonates undergoing CPB in the first 30 days of life were studied. Blood samples were obtained during and after surgery. Heparin-protamine balance was assessed with calibrated automated thrombography, thrombin-initiated fibrin clot kinetic assay (TFCK), activated partial thromboplastin time (APTT), anti-FXa activity, and thromboelastometry. Excessive postoperative bleeding was determined by measurement of chest tube output or the development of cardiac tamponade. Results and Conclusions Of 44 neonates enrolled, 16 (36%) had excessive postoperative bleeding. The TFCK value was increased. By heparin in neonatal blood samples, but was only minimally altered by excess protamine. Therefore, it reliably measured heparin in samples containing a wide range of heparin and protamine concentrations. The APTT most closely correlated with TFCK results, whereas anti-FXa and thromboelastometry assays were less correlative. The TFCK and APTT assay also consistently detected postoperative heparin rebound, providing an important continued role for these long-established coagulation tests in the management of postoperative bleeding in neonates requiring cardiac surgical repair. None of the coagulation tests predicted the neonates who experienced postoperative bleeding, reflecting the multifactorial causes of bleeding in this population.

A ratiometric detection of heparin with high sensitivity based on aggregation-enhanced emission of gold nanoclusters triggered by silicon nanoparticles

Heparin (Hep) is a widely applied anticoagulant and the quantification of heparin concentration is pivotal for clinical use. In this work, silicon nanoparticles (SiNPs) modified by the amino groups and glutathione-capped gold nanoclusters (GSH-AuNCs) are able to self-assemble into spherical particle structures via the electrostatic interaction, resulting in the aggregation-enhanced emission (AEE) of GSH-AuNCs. However, Hep, a highly sulfated glycosaminoglycan with much more negative charges, can bind with the SiNPs and inhibit the aggregation. As a result, it causes the AEE quenching of GSH-AuNCs at 570 nm but the SiNPs keep their own blue fluorescence at 450 nm. Thus, the SiNPs can act as an internal reference and the GSH-AuNCs are used as a signal probe in this process. The ratiometric fluorescent signal (I570/I450) change of the nanohybrid probe is positively correlated with Hep concentrations in the range from 6.44 ng/mL to 96.6 ng/mL with the detection limit of 3.29 ng/mL. As expected, this strategy shows good sensitivity and selectivity, and it is also successfully applied to detect Hep in Hep sodium injection and human serum samples with good recoveries.

DMD TREATMENT: ANIMAL MODELS: P.207Full-length but not truncated osteoprotegerin binds directly to muscle cells and increases rapidly dystrophic muscle force

Clinical studies have shown that osteoporosis and muscle degeneration can occur in tandem following neuromuscular diseases. The receptor-activator of nuclear factor κB (RANK), the receptor-activator of nuclear factor κB ligand (RANKL), and osteoprotegerin (OPG) triad, a key pathway for bone regulation, is involved in Duchenne muscular dystrophy physiopathology. OPG, a decoy receptor for RANKL, the truncated (TR-OPG-Fc) or full-length OPG (FL-OPG-Fc) fused with an Fc fragment of IgG1 can inhibit RANKL/RANK interactions in vivo or in vitro. TR-OPG-Fc contains only 4 cysteine-rich RANKL domains while FL-OPG-Fc contains 4 cysteine-rich RANKL domains, 2 TRAIL death domains and 1 heparin-binding domain. We have shown that a 10 day treatment with FL-OPG-Fc during the first acute phase of degeneration in dystrophin-deficient mdx mice completely restored force and resistance to eccentric contractions of fast-twitch muscle. Because FL-OPG-Fc was superior to muscle specific deletion of RANK or anti-RANKL, anti-TRAIL, TR-OPG-Fc treatments, we hypothesized that the heparin-binding domain found in FL-OPG-Fc interacts directly with muscle. WB and confocal microscopy demonstrated that FL-OPG-Fc, but not TR-OPG-Fc, binds to C2C12 myotube. We next showed that heparinase III, which cleaves heparan sulfate chains, reduces FL-OPG-Fc binding by 50%. To further support the importance of the heparin domain, FL-OPG-Fc was co-incubated with equal concentration of heparin, which abrogated by 85% its binding ability. Next, using ex vivo contractile properties of isolated fast-twitch EDL, we showed that a 24h FL-OPG-Fc treatment increased significantly the absolute and specific forces of dystrophic EDL. In conclusion, FL-OPG-Fc, through its heparin-binding domain, binds directly muscle cells and can rapidly increase absolute and specific maximal tetanic forces. Current investigations are directed towards a better understanding of the mechanisms by which FL-OPG-Fc improves dystrophic muscles.

Convectively Dominated Heparin Leakage From Multiple Catheter Designs: An In Vitro Experimental Study.

Central venous catheters (CVCs) are routinely filled with a heparin lock while not in use to avoid thrombus formation near the tip. However, heparin leakage is known to occur, and the lock effectiveness remains in question. It was recently shown that convective fluxes from the blood flow in the host vein transport the majority of locking solution away from the tip of hemodialysis catheters immediately after instillation. Combined with the low diffusivity of heparin, this results in concentrations of heparin at the catheter tip that are orders of magnitude lower than at instillation for the majority of the interdialytic phase, diminishing the antithrombotic effectiveness of the lock. In this study, heparin losses from three different CVCs with different tip designs are measured in a pulsatile flow loop. Planar laser-induced fluorescence and particle image velocimetry measurements of heparin concentration and fluid velocity are recorded downstream of the catheters and combined to evaluate heparin losses from each of the different catheter designs. Additionally, locking solution losses are measured from one catheter (Hickman) subjected to three different flow conditions. Heparin losses are shown to depend weakly on flow condition but be highly dependent on catheter design. Convective losses from the Hickman catheter, with no side holes, are minimal (1-2%), although losses from the other two catheter types, both with a number of side holes, are significantly higher (7%). These results indicate the potential to maintain a high concentration of locking solution during the interdialytic phase with proper catheter design, particularly focusing on side hole distribution and shape.

Magnetic Dendritic Halloysite Nanotube for Highly Selective Recovery of Heparin Digested from Porcine Intestinal Mucosa

Heparin, as a sulfated polysaccharide found in animal tissues, is a commonly employed clinical anticoagulant. However, the heparin concentration in digested raw materials is very low and difficult to recover at high concentrations. To address this issue and enrich the heparin content that can be purified, we have fabricated novel polyamidoamine (PAMAM) dendrimers functionalized on halloysite nanotubes (HNTs), which were also decorated and magnetized with iron oxide (Fe3O4) nanoparticles to enable magnetic separation for selective, scalable recovery of heparin. Using absorption spectroscopy, the heparin recovery efficiency of HNTs and PAMAM-Fe3O4/HNTs was evaluated and compared the results to Amberlite FPA98 Cl, a commercially accessible resin used in heparin extraction. Our results showed that the PAMAM-Fe3O4/HNTs demonstrated higher efficiency of heparin recovery, both in terms of the capacity and rate of adsorption. We also studied the adsorption mechanism of heparin onto the functional amino groups of ...

Adjusted calculation model of heparin management during cardiopulmonary bypass in obese patients: A randomised controlled trial.

Anticoagulation during cardiopulmonary bypass (CPB) is usually adapted to total body weight (TBW). This may be inaccurate in obese patients and lead to heparin overdose with a risk of bleeding. To validate the efficacy and safety of an adjusted calculation model of heparin dosing based on ideal body weight (IBW) rather than TBW in obese CPB patients, with an expected target mean plasma heparin concentration of 4.5 IU ml after onset of CPB in the experimental group. Randomised controlled study. University hospital. Sixty obese patients (BMI ≥ 30 kg m) scheduled for CPB were included from January to June 2016. Patients received a bolus dose of unfractionated heparin of either 300 IU kg of TBW or 340 IU kg of IBW before onset of CPB. Additional adjusted boluses were injected to maintain an activated clotting time (ACT) of at least 400 s. Plasma heparin concentration and ACT were measured at different time points. Total heparin doses and transfusion requirements were recorded. The target heparin concentration of 4.5 IU ml was reached in the IBW group at the onset of CPB and maintained at all time points during CPB. Heparin concentrations were significantly higher in the TBW group after the bolus (6.52 ± 0.97 vs. 4.54 ± 1.13 IU ml, P < 0.001) and after cardioplegia (5.10 ± 1.03 vs. 4.31 ± 1.00 IU ml, P = 0.02). Total heparin doses were significantly higher in the TBW group. Mean ACT was significantly lower in the IBW group but remained over 400 s during CPB. The correlation between heparin and ACT was poor. Peri-operative bleeding and transfusion requirements were comparable. No thrombotic event occurred in the CPB circuit. The current IBW-adjusted regimen of heparin administration may be used efficiently in obese CPB patients, thereby avoiding overdose which cannot be accurately assessed by ACT monitoring alone. ClinicalTrials.gov identifier: NCT02675647.

Heparin versus 0.9% sodium chloride locking for prevention of occlusion in central venous catheters in adults

Intermittent locking of central venous catheters (CVCs) is undertaken to help maintain their patency. There are systematic variations in care: some practitioners use heparin (at different concentrations), whilst others use 0.9% NaCl (normal saline). This review looks at the effectiveness and safety of intermittent locking with heparin compared to 0.9% NaCl to see if the evidence establishes whether one is better than the other. This work is an update of a review first published in 2014. To assess the effectiveness and safety of intermittent locking of CVCs with heparin versus normal saline (NS) in adults to prevent occlusion. The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (last searched 11 June 2018) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 5). Searches were also carried out in MEDLINE, Embase, CINAHL, and clinical trials databases (11 June 2018). We included randomised controlled trials in adults ≥ 18 years of age with a CVC that compared intermittent locking with heparin at any concentration versus NS. We applied no restriction on language. Two review authors independently selected trials, assessed quality, and extracted data. We contacted trial authors to retrieve additional information, when necessary. We carried out statistical analysis using Review Manager 5 and assessed the overall quality of the evidence supporting assessed outcomes using GRADE. We carried out prespecified subgroup analysis. We identified five new studies for this update (six prior studies were included in the original review), bringing the number of eligible studies to 11, with a total of 2392 participants. We noted differences in methods used by the included studies and variation in heparin concentrations (10 to 5000 IU/mL), time to follow-up (1 to 251.8 days), and the unit of analysis used (participant, catheter, line access).Combined results from these studies showed fewer occlusions with heparin than with NS (risk ratio (RR) 0.70, 95% confidence interval (CI) 0.51 to 0.95; P = 0.02; 1672 participants; 1025 catheters from 10 studies; I² = 14%) and provided very low-quality evidence.We carried out subgroup analysis by unit of analysis (testing for subgroup differences (P = 0.23; I² = 30.3%). When the unit of analysis was the participant, results show no clear differences in all occlusions between heparin and NS (RR 0.79, 95% CI 0.58 to 1.08; P = 0.15; 1672 participants; seven studies). Subgroup analysis using the catheter as the unit of analysis shows fewer occlusions with heparin use (RR 0.53, 95% CI 0.29 to 0.95; P = 0.03; 1025 catheters; three studies). When the unit of analysis was line access, results show no clear differences in occlusions between heparin and NS (RR 1.08, 95% CI 0.84 to 1.40; 770 line accesses; one study).We found no clear differences in the duration of catheter patency (mean difference (MD) 0.44 days, 95% CI -0.10 to 0.99; P = 0.11; 1036 participants; 752 catheters; six studies; low-quality evidence).We found no clear evidence of a difference in the following: CVC-related sepsis (RR 0.74, 95% CI 0.03 to 19.54; P = 0.86; 1097 participants; two studies; low-quality evidence); mortality (RR 0.76, 95% CI 0.44 to 1.31; P = 0.33; 1100 participants; three studies; low-quality evidence); haemorrhage at any site (RR 1.32, 95% CI 0.57 to 3.07; P = 0.52; 1245 participants; four studies; moderate-quality evidence); or heparin-induced thrombocytopaenia (RR 0.21, 95% CI 0.01 to 4.27; P = 0.31; 443 participants; three studies; low-quality evidence).The main reasons for downgrading the quality of evidence were unclear allocation concealment, imprecision, and suspicion of publication bias. Given the very low quality of the evidence, we are uncertain whether intermittent locking with heparin results in fewer occlusions than intermittent locking with NS. Low-quality evidence suggests that heparin may have little or no effect on catheter patency. Although we found no evidence of differences in safety (sepsis, mortality, or haemorrhage), the combined trials are not powered to detect rare adverse events such as heparin-induced thrombocytopaenia.

Rapid detection of heparin by gold nanorods and near-infrared fluorophore ensemble based platform via nanometal surface energy transfer

As a mucopolysaccharide sulfate anticoagulant drug, heparin plays important roles in clinic. In this work, heparin was analyzed based on the nanometal surface energy transfer (NSET) between gold nanorods (AuNRs) and tetrakis (4-sulfophenyl) porphyrin (TPPS4) fluorescent molecules. The results showed that AuNRs could bind TPPS4 by electrostatic interaction and coordination to quench its fluorescence. While heparin was able to bind AuNRs with a stronger electrostatic interaction to compel TPPS4 to leave AuNRs surface, leading to the fluorescence recovery of TPPS4, which was proportional to the concentration of heparin in a range of 0.05∼2 μg/mL with the detection limit as low as 6.7 ng/mL (3σ). Based on this, a NSET platform for the analysis of trace heparin sodium was proposed with fast response, high sensitivity and excellent specificity, which was successfully applied to the detection of heparin in injection with the satisfactory result. Importantly, the NSET mechanism was fully discussed.

Anticalcification potential of heparin on hydroxyapatite seeds using a constant composition in vitro model

Calcification is among the principal causes of biological heart valve substitute failure. Glycosaminoglcans (GAGs) are negatively charged molecules, possessing anticoagulation and anti-inflammatory activity that make them a potential solution against calcification. In the present work, the anticalcification potential of heparin was investigated under constant supersaturation conditions with respect to hydroxyapatite (Ca5(PO4)3OH; HAP). Heparin concentration in the supersaturated solutions was in the range between 0.25 and 3 ppm, at pH 7.40 and 37 °C. Heparin showed inhibitory activity, which was attributed to adsorption at the active crystal growth centres. Heparin concentration as low as ca. 50 μM, reduced the rate of HAP crystal growth by more than 80%, while further increase (up to 200 μM) failed to completely inhibit the process beyond 90%. Heparin uptake studies at equilibrium conditions and analysis of the kinetics data in the presence of heparin, strongly suggest that the inhibition is due to the adsorption of heparin onto the HAP crystals, which resulted in the poisoning of the active growth sites.

Microenvironmental support for cell delivery to the inner ear

Transplantation of mesenchymal stromal cells (MSC) presents a promising approach not only for the replacement of lost or degenerated cells in diseased organs but also for local drug delivery. It can potentially be used to enhance the safety and efficacy of inner ear surgeries such as cochlear implantation. Options for enhancing the effects of MSC therapy include modulating cell behaviour with customized bio-matrixes or modulating their behaviour by ex vivo transfection of the cells with a variety of genes. In this study, we demonstrate that MSC delivered to the inner ear of guinea pigs or to decellularized cochleae preferentially bind to areas of high heparin concentration. This presents an opportunity for modulating cell behaviour ex vivo. We evaluated the effect of carboxymethylglucose sulfate (Cacicol®), a heparan sulfate analogue on spiral ganglion cells and MSC and demonstrated support of neuronal survival and support of stem cell proliferation.

Ultrasensitive detection of heparin by exploiting the silver nanoparticle-enhanced fluorescence of graphitic carbon nitride (g-C3N4) quantum dots.

A composite (Ag-g-CNQDs) was prepared from graphitic carbon nitride quantum dots and silver nanoparticles by water phase synthesis. Aided by metal-enhanced fluorescence, the composite exhibits excitation-dependent red emission with a peak at 600nm with a quantum yield of 21%. If the composite is coated with polyethylenimine (PEI) to form the Ag-g-CNQD/PEI complexe, fluorescence is strongly reduced. Upon addition of heparin, the fluorescence of the system is enhanced because PEI has a higher affinity for heparin than Ag-g-CNQDs. The effect was used to design a fluorometric assay for heparin.The emission at 600nm increases linearly in the 0.025 to 2.5μM heparin concentration range, with a 8.2nM limit of detection. Graphical abstract Schematic illustration for fabricating a composite consisting of silver nanoparticles and graphitic carbon nitride quantum dots (Ag-g-CNQDs). Its redfluorescence is weak in presence of polyethyleneimine but restored on addition of heparin. This forms the basis for anew method for heparin detection.