Clinical Features and Treatment Response in Immune-Mediated Small Fiber Neuropathy with Trisulfated Heparin Disaccharide or Fibroblast Growth Factor Receptor 3 Antibodies.

OBJECTIVE: Novel antibodies to trisulfated heparin disaccharide (TS-HDS) and fibroblast growth factor receptor 3 (FGFR-3) have been recently described in otherwise cryptogenic small fiber neuropathy (SFN) cases. Our goal was to further describe clinical features in such cases and to analyze treatment responses. METHODS: In a retrospective analysis, 40 cases of cryptogenic SFN in a university neuropathy clinic were identified. Of these, TS-HDS and FGFR-3 cases were identified, and clinical features and treatment responses were analyzed. RESULTS: In this cohort, 95% were women, and 55% had either TS-HDS or FGFR-3 antibodies (77% of these had TS-HDS). Of the seropositive group, 41% had a nonlength dependent epidermal nerve fiber density on skin punch biopsy (OR = 1.80). In the seropositive group, 82% had neuropathic pain as their primary symptom (OR = 1.73). Also 32% of seropositive patients reported widespread pain (OR = 1.63). 63% of seropositive cases presented acutely (OR = 11.0). In the seropositive group, 23% had an initial erroneous diagnosis (OR = 1.47). Eight seropositive patients improved on intravenous immunoglobulin treatment, with a 42% reduction in pain scores (P = 0.02), a 44% reduction in the Utah Neuropathy Score, and improved epidermal nerve fiber density post-treatment. CONCLUSIONS: TS-HDS and FGFR-3 antibodies may be present in a high proportion of cryptogenic SFN cases with acute onset, nonlength dependent pathology, and primary neuropathic and widespread pain. They are often misdiagnosed as other conditions including fibromyalgia. These cases may be responsive to immune treatment, especially with intravenous immunoglobulin.

Comparative metabolomics studies of blood collected in streck and heparin tubes from lung cancer patients.

Metabolomics analysis of blood from patients (n = 42) undergoing surgery for suspected lung cancer was performed in this study. Venous and arterial blood was collected in both Streck and Heparin tubes. A total of 96 metabolites were detected, affected by sex (n = 56), collection tube (n = 33), and blood location (n = 8). These metabolites belonged to a wide array of compound classes including lipids, acids, pharmaceutical agents, signalling molecules, vitamins, among others. Phospholipids and carboxylic acids accounted for 28% of all detected compounds. Out of the 33 compounds significantly affected by collection tube, 18 compounds were higher in the Streck tubes, including allantoin and ketoleucine, and 15 were higher in the Heparin tubes, including LysoPC(P-16:0), PS 40:6, and chenodeoxycholic acid glycine conjugate. Based on our results, it is recommended that replicate blood samples from each patient should be collected in different types of blood collection tubes for a broader range of the metabolome. Several metabolites were found at higher concentrations in cancer patients such as lactic acid in Squamous Cell Carcinoma, and lysoPCs in Adenocarcinoma and Acinar Cell Carcinoma, which may be used to detect early onset and/or to monitor the progress of the cancer patients.

Early detection of deep vein thrombosis in patients with coronavirus disease 2019: who to screen and who not to with Doppler ultrasound?

PURPOSE: Aim of the study is to evaluate the incidence of DVT in COVID-19 patients and its correlation with the severity of the disease and with clinical and laboratory findings. METHODS: 234 symptomatic patients with COVID-19, diagnosed according to the World Health Organization guidelines, were included in the study. The severity of the disease was classified as moderate, severe and critical. Doppler ultrasound (DUS) was performed in all patients. DUS findings, clinical, laboratory's and therapeutic variables were investigated by contingency tables, Pearson chi square test and by Student t test and Fisher's exact test. ROC curve analysis was applied to study significant continuous variables. RESULTS: Overall incidence of DVT was 10.7% (25/234): 1.6% (1/60) among moderate cases, 13.8% (24/174) in severely and critically ill patients. Prolonged bedrest and intensive care unit admission were significantly associated with the presence of DVT (19.7%). Fraction of inspired oxygen, P/F ratio, respiratory rate, heparin administration, D-dimer, IL-6, ferritin and CRP showed correlation with DVT. CONCLUSION: DUS may be considered a useful and valid tool for early identification of DVT. In less severely affected patients, DUS as screening of DVT might be unnecessary. High rate of DVT found in severe patients and its correlation with respiratory parameters and some significant laboratory findings suggests that these can be used as a screening tool for patients who should be getting DUS.

A rolling circle amplification based platform for ultrasensitive detection of heparin.

Heparin has a variety of pharmacological uses, including applications for anti-tumor metastasis, anti-inflammatory and anti-viral activities and is widely used as a clinical anticoagulant. Due to its widespread applications in the clinical procedures, monitoring heparin levels is critically important to ensure the safe use of heparin and to prevent overdose and complications, such as hemorrhage and thrombocytopenia. However, traditional heparin detection relies on the measurements of the activated clotting time or activated partial thromboplastin time, which are not sufficiently reliable or accurate measurements for certain clinical settings. In this work, we describe a dumbbell probe-aided strategy for ultrasensitive and isothermal detection of heparin based on a uniquely strong protamine-heparin interaction and rolling circle amplification driven signal amplification. The detection limit for heparin is 12.5 ng mL-1 (0.83 nM), which is much lower than the therapeutic level of heparin in cardiovascular surgery (17-67 µM) and in postoperative and long-term treatment (1.7-10 µM). Additionally, the proposed sensing platform works well for heparin monitoring in human plasma samples. This simple and ultrasensitive heparin biosensor has potential application in diagnostics, therapeutics, and in biological research.

Heparin concentration in cell salvage during heparinization: a pilot study.

Cell salvage is frequently used to avoid unnecessary allogeneic blood transfusions, which results in a reduction in blood transfusion volume and cost. The aspirated blood is washed with normal saline and centrifuged to recover only blood cells, salvaged blood is then made. In cardiovascular surgery, heparin is used to maintain activated clotting time over 400 seconds. Some practitioners believe that heparin remains in the salvaged blood. Therefore, we hypothesized that salvaged blood during cardiovascular surgery includes heparin. A pilot study was conducted to evaluate our hypothesis using three different salvage systems. This study was a prospective, observational, pilot study, with patients aged 20-85 years old who were scheduled for cardiovascular surgery from May 2018 to October 2018. The intent of this study was to evaluate whether salvaged blood with three different devices includes large enough quantities of heparin to influence activated clotting time in cardiovascular surgery. Between May and October 2018, 12 samples during heparinization were collected, and 12 samples of salvaged blood from 3 devices were collected after administrating protamine. The heparin concentration of the 24 samples was measured. All heparin concentrations in salvage blood sample from two devices was below the limit of measurement (0.10 IU/mL). Slightly measurable heparin was detected in salvaged blood sample from one device (mean 0.15 IU/mL). Salvaged blood during cardiovascular surgery intervention does not contain enough heparin to influence activated clotting time.

Rethinking the one-size-fits-most approach to venous thromboembolism prophylaxis after radical cystectomy.

OBJECTIVES: Empirically dosed enoxaparin is routinely given in the postoperative period for venous thromboembolism (VTE) prophylaxis after radical cystectomy (RC). Patient-specific factors may alter its pharmacokinetics, and it is unclear whether this leads to levels sufficient for antithrombosis. We sought to evaluate variability of anti-factor Xa levels in a cohort of RC patients receiving perioperative enoxaparin prophylaxis. MATERIAL AND METHODS: Patients undergoing RC at a single institution were placed on a postoperative pathway that included enoxaparin. An anti-factor Xa level was drawn 2 to 4 hours after the third dose. The target range for prophylaxis was 0.3 IU/ml to 0.5 IU/ml. RESULTS: The primary outcome was anti-factor Xa level. Demographics, operative time, hospital course, and 30-days post-operative VTE were compared by anti-factor Xa level group using univariate and multivariable analyses. Between January 2018 and 2019, 107 RC patients remained on pathway and were included in our analysis. Sixty-five (61%) were below target range for VTE prophylaxis.  A single VTE event (0.9%) occurred in a subprophylactic individual. The subprophylactic group had a significantly higher body mass index (P < 0.01) than those within target range. CONCLUSIONS: Higher body mass index was associated with subprophylactic enoxaparin dosing after RC. Nearly two-thirds of patients had below target anti-factor Xa levels. This suggests that dosing could be further individualized, but given the low incidence of VTE, implications of dose-adjusted prophylaxis on VTE prevention remain unknown.

Highly Sensitive and Selective Detection of Heparin in Serum Based on a Long-Wavelength Tetraphenylethylene-Cyanopyridine Aggregation-Induced Emission Luminogen.

A positively charged aggregation-induced emission luminogen (AIEgen), TPE-P+, was constructed by linking a pyridyl cation to tetraphenylethylene (TPE) via a cyanoethylene bond. TPE-P+ can realize the identification of heparin (Hep) by aggregating with negatively charged Hep via electrostatic interactions. Upon addition of Hep, TPE-P+ exhibited 36-fold fluorescence enhancement in less than 5 s, exhibiting quick and sensitive response to Hep with a low detection limit down to 4 nM. Among various biological substances, even Hep analogs like chondroitin 4-sulfate and hyaluronic acid, TPE-P+ showed the most significant fluorescence enhancement to Hep only, demonstrating its excellent selectivity for Hep. In particular, with long-wavelength emission near 600 nm and large stocks shift (∼160 nm), TPE-P+ enabled minimization of autofluorescence interference from a complex biological matrix and provided more accurate results. Finally, TPE-P+ was successfully applied for sensitive and selective detection of Hep in serum. Notably, there existed a good linear relationship in a serum assay when the Hep concentration ranging from 0 to 4 µM (R2 = 0.9934) covered the clinical dosage level during both cardiovascular surgery and long-term care, suggesting the potential clinical practice for quantifying Hep in serum. Moreover, TPE-P+-Hep complex can be further disaggregated by protamine (PRTM) due to the stronger affinity between Hep and PRTM, thereby leading to further detection of PRTM effectively. Last, but not least, the "off-on-off" system designed for both Hep and PRTM detection proved to be reversible.

Potential and Limitations of the New P2Y12 Inhibitor, Cangrelor, in Preventing Heparin-Induced Platelet Aggregation During Cardiac Surgery: An In Vitro Study.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) can put cardiac surgery patients at a high risk of lethal complications. If anti-PF4/heparin antibodies (anti-PF4/Hep Abs) are present, 2 strategies exist to prevent intraoperative aggregation during bypass surgery: first, using an alternative anticoagulant, and second, using heparin combined with an antiaggregant. The new P2Y12 inhibitor, cangrelor, could be an attractive candidate for the latter strategy; several authors have reported its successful use. The present in vitro study evaluated cangrelor's ability to inhibit heparin-induced platelet aggregation in the presence of anti-PF4/Hep Abs. METHODS: Platelet-poor plasma (PPP) from 30 patients with functional anti-PF4/Hep Abs was mixed with platelet-rich plasma (PRP) from 5 healthy donors.Light transmission aggregometry was used to measure platelet aggregation after adding 0.5 IU·mL of heparin (HIT) to the plasma, and this was compared with samples spiked with normal saline (control) and samples spiked with cangrelor 500 ng·mL and heparin 0.5 IU·mL (treatment). Friedman test with post hoc Dunn-Bonferroni test was used for between-group comparisons. RESULTS: Heparin 0.5 IU·mL triggered aggregation in 22 of 44 PPP-PRP mixtures, with a median aggregation of 86% (interquartile range [IQR], 69-91). The median aggregation of these 22 positive samples' respective control tests was 22% (IQR, 16-30) (P < .001). Median aggregation in the cangrelor-treated samples was 29% (IQR, 19-54) and significantly lower than the HIT samples (P < .001). Cangrelor inhibited heparin-induced aggregation by a median of 91% (IQR, 52-100). Cangrelor only reduced heparin-induced aggregation by >95% in 10 of the 22 positive samples (45%). Cangrelor inhibited heparin-induced aggregation by <50% in 5 of the 22 positive samples (22%) and by <10% in 3 samples (14%). CONCLUSIONS: This in vitro study found that cangrelor was an unreliable inhibitor of heparin-induced aggregation in the presence of anti-PF4/Hep Abs. We conclude that cangrelor should not be used as a standard antiaggregant for cardiac patients affected by HIT during surgery. Unless cangrelor's efficacy in a particular patient has been confirmed in a presurgery aggregation test, other strategies should be chosen.

Prophylactic Enoxaparin Adjusted by Anti-Factor Xa Peak Levels Compared with Recommended Thromboprophylaxis and Rates of Clinically Evident Venous Thromboembolism in Surgical Oncology Patients.

BACKGROUND: Studies among populations at high risk of venous thromboembolism (VTE) have demonstrated that recommended doses for enoxaparin thromboprophylaxis are associated with high incidence of subprophylactic anti-factor Xa (anti-Xa) levels. This study examines the efficacy and safety of dose-adjusted enoxaparin guided by anti-Xa levels. STUDY DESIGN: Patients undergoing abdominal cancer operation had dose adjustments based on peak anti-Xa levels to attain a target of >0.20 IU/mL were prospectively enrolled and compared with a historic cohort of patients receiving recommended thromboprophylaxis. Incidence of in-hospital VTE and major bleeding after changes in enoxaparin dosing were monitored. RESULTS: The study population comprised 197 patients-64 patients in the prospective intervention group and 133 patients in the control group. Baseline characteristic were similar between the intervention and control groups, with the exception of the Caprini score (8.09 vs 7.26; p = 0.013). In the intervention group, 50 of 64 patients (78.1%) initially had subprophylactic peak anti-Xa levels. The VTE rates were lower in the intervention group than the control group (0% vs 8.27%; p = 0.018). There were no differences in major bleeding events (3.12% vs 1.50%; p = 0.597), rates of postoperative packed RBC transfusion (17.2% vs 23.3%; p = 0.426), or mean Hgb on discharge (9.58 vs 9.37g/dL; p = 0.414). Therapeutic anti-Xa levels correlated positively with age (65.7 vs 58.2 years; p = 0.022) and correlated negatively with operating room time (203 vs 281 minutes; p = 0.032) and BMI (25.3 vs 29.2 kg/m2; p = 0.037). CONCLUSIONS: Thromboprophylactic enoxaparin 40 mg daily is often associated with subprophylactic peak anti-Xa levels. Dose adjustment based on anti-Xa levels increased the daily enoxaparin dose, resulting in a lower rate of in-hospital VTE without increased risk of bleeding.

Heparin Forms Polymers with Cell-free DNA Which Elongate Under Shear in Flowing Blood.

Heparin is a widely used anticoagulant which inhibits factor Xa and thrombin through potentiation of antithrombin. We recently identified that the nucleic acid stain SYTOX reacts with platelet polyphosphate due to molecular similarities, some of which are shared by heparin. We attempted to study heparin in flowing blood by live-cell fluorescence microscopy, using SYTOX for heparin visualisation. Immunostaining was performed with monoclonal antibodies directed against various heparin-binding proteins. In addition, we studied modulation of heparin activity in coagulation assays, as well its effects on fibrin formation under flow in recalcified whole blood. We found that SYTOX-positive polymers appear in heparinised blood under flow. These polymers typically associate with platelet aggregates and their length (reversibly) increases with shear rate. Immunostaining revealed that of the heparin-binding proteins assessed, they only contain histones. In coagulation assays and flow studies on fibrin formation, we found that addition of exogenous histones reverses the anticoagulant effects of heparin. Furthermore, the polymers do not appear in the presence of DNase I, heparinase I/III, or the heparin antidote protamine. These findings suggest that heparin forms polymeric complexes with cell-free DNA in whole blood through a currently unidentified mechanism.

Current Diagnosis and Treatment of Painful Small Fiber Neuropathy.

PURPOSE OF REVIEW: Small fiber neuropathy (SFN) could cause significant morbidity due to neuropathic pain and autonomic dysfunction. SFN is underdiagnosed and the knowledge on the condition is limited among general public and health care professionals. This review is intended to enhance the understanding of SFN symptoms, causes, diagnostic tools, and therapeutic options. RECENT FINDINGS: There is evidence of SFN in up to 40% patients with fibromyalgia. The causes of SFN are glucose metabolism defect, dysimmune, gluten sensitivity and celiac disease, monoclonal gammopathy, vitamin deficiencies, toxic agents, cancer, and unknown etiology. Auto-antibodies targeting neuronal antigens trisulfated heparin disaccharide (TS-HDS) and fibroblast growth factor 3 (FGFR3) are found in up to 20% of patients with SFN. Treatment of SFN includes treating the etiology and managing symptoms. SFN should be considered in patients with wide-spread body pain. The search for known causes of SFN is a crucial step in disease management.

Self-assembled multivalent (SAMul) ligand systems with enhanced stability in the presence of human serum.

Self-assembled cationic micelles are an attractive platform for binding biologically-relevant polyanions such as heparin. This has potential applications in coagulation control, where a synthetic heparin rescue agent could be a useful replacement for protamine, which is in current clinical use. However, micelles can have low stability in human serum and unacceptable toxicity profiles. This paper reports the optimisation of self-assembled multivalent (SAMul) arrays of amphiphilic ligands to bind heparin in competitive conditions. Specifically, modification of the hydrophobic unit kinetically stabilises the self-assembled nanostructures, preventing loss of binding ability in the presence of human serum - cholesterol hydrophobic units significantly outperform systems with a simple aliphatic chain. It is demonstrated that serum albumin disrupts the binding thermodynamics of the latter system. Molecular simulation shows aliphatic lipids can more easily be removed from the self-assembled nanostructures than the cholesterol analogues. This agrees with the experimental observation that the cholesterol-based systems undergo slower disassembly and subsequent degradation via ester hydrolysis. Furthermore, by stabilising the SAMul nanostructures, toxicity towards human cells is decreased and biocompatibility enhanced, with markedly improved survival of human hepatoblastoma cells in an MTT assay.

No interactions between heparin and atacicept, an antagonist of B cell survival cytokines.

BACKGROUND AND PURPOSE: The TNF family ligands, B cell activating factor of the TNF family (BAFF, also known as B lymphocyte stimulator, BLyS) and a proliferation-inducing ligand (APRIL), share the transmembrane activator and calcium-modulator and cyclophilin ligand (CAML)-interactor (TACI) as one of their common receptors. Atacicept, a chimeric recombinant TACI/IgG1-Fc fusion protein, inhibits both ligands. TACI and APRIL also bind to proteoglycans and to heparin that is structurally related to proteoglycans. It is unknown whether the portion of TACI contained in atacicept can bind directly to proteoglycans, or indirectly via APRIL, and whether this could interfere with the anti-coagulant properties of heparin. EXPERIMENTAL APPROACH: Binding of atacicept and APRIL to proteoglycan-positive cells was measured by FACS. Activities of heparin and atacicept were measured with activated factor Xa inhibition and cell-based assays. Effects of heparin on circulating atacicept was monitored in mice. KEY RESULTS: Atacicept did not bind to proteoglycan-positive cells, but when complexed to APRIL could do so indirectly via APRIL. Multimers of atacicept obtained after exposure to cysteine or BAFF 60-mer bound directly to proteoglycans. Atacicept alone, or in complex with APRIL, or in a multimeric form did not interfere with heparin activity in vitro. Conversely, heparin did not influence inhibition of BAFF and APRIL by atacicept and did not change circulating levels of atacicept. CONCLUSIONS AND IMPLICATIONS: Lack of detectable interference of APRIL-bound or free atacicept on heparin activity makes it unlikely that atacicept at therapeutic doses will interfere with the function of heparin in vivo.

Relationship between free hemoglobin (hemolysis), potassium and ionized calcium in lithium heparin blood gas samples collected intraoperatively.

OBJECTIVE: Develop sample acceptability rules by determining the relationship between free hemoglobin level (hemolysis) and potassium or ionized calcium in blood gas samples collected intraoperatively. DESIGN AND METHODS: Hemolysis was assessed visually or by H index for lithium heparin blood gas samples collected intraoperatively. During periods one and three this was done using two different rules for visual assessment of centrifuged lithium heparin plasma. During period two H index was measured for all visually hemolyzed samples on a Roche Cobas c501 analyzer to determine acceptability. Potassium and ionized calcium were measured in 75 lithium heparin whole blood samples on a Radiometer ABL90 to correlate H index and potassium or ionized calcium. RESULTS: During period one 35 of 5808 (0.6%) blood gas samples had visual hemolysis levels exceeding tolerance for reporting of potassium. By switching to measured H index using a laboratory-established threshold, during period 2 we estimate that 171 of 5396 (3.2%) blood gas samples exceeded the H index threshold for reporting of potassium. In 75 intraoperative blood gas samples with H index and whole blood potassium and ionized calcium measured; we observed no relationship between H index and potassium or ionized calcium. During period 3 we switched to visual assessment of hemolysis with a greater tolerance for hemolysis; with only 3 of 5345 (0.06%) samples exceeding the new visual hemolysis threshold. CONCLUSION: For blood gas samples collected intraoperatively, there is no relationship between hemolysis and measured potassium or ionized calcium. The results suggest that only grossly hemolyzed intraoperative blood gas samples should be rejected for measurement of whole blood potassium and ionized calcium.

The glycocalyx: a novel diagnostic and therapeutic target in sepsis.

The glycocalyx is a gel-like layer covering the luminal surface of vascular endothelial cells. It is comprised of membrane-attached proteoglycans, glycosaminoglycan chains, glycoproteins, and adherent plasma proteins. The glycocalyx maintains homeostasis of the vasculature, including controlling vascular permeability and microvascular tone, preventing microvascular thrombosis, and regulating leukocyte adhesion.During sepsis, the glycocalyx is degraded via inflammatory mechanisms such as metalloproteinases, heparanase, and hyaluronidase. These sheddases are activated by reactive oxygen species and pro-inflammatory cytokines such as tumor necrosis factor alpha and interleukin-1beta. Inflammation-mediated glycocalyx degradation leads to vascular hyper-permeability, unregulated vasodilation, microvessel thrombosis, and augmented leukocyte adhesion. Clinical studies have demonstrated the correlation between blood levels of glycocalyx components with organ dysfunction, severity, and mortality in sepsis.Fluid resuscitation therapy is an essential part of sepsis treatment, but overaggressive fluid therapy practices (leading to hypervolemia) may augment glycocalyx degradation. Conversely, fresh frozen plasma and albumin administration may attenuate glycocalyx degradation. The beneficial and harmful effects of fluid and plasma infusion on glycocalyx integrity in sepsis are not well understood; future studies are warranted.In this review, we first analyze the underlying mechanisms of glycocalyx degradation in sepsis. Second, we demonstrate how the blood and urine levels of glycocalyx components are associated with patient outcomes. Third, we show beneficial and harmful effects of fluid therapy on the glycocalyx status during sepsis. Finally, we address the concept of glycocalyx degradation as a therapeutic target.

[Hemorrhagic syndrome due to a heparin-like anticoagulant in a patient with systemic lupus erythematosus]. / Syndrome hémorragique dû à un anticoagulant héparine-like chez un patient lupique.

INTRODUCTION: In systemic lupus erythematosus, hemostasis disorders are mainly thrombotic, but more rarely hemorrhagic. CASE REPORT: A 25-year-old man presented with a macrophagic activation syndrome revealing a systemic lupus erythematosus, secondarily complicated by a hemorrhagic syndrome ; biological investigations revealed an increase thrombin time and an activated partial thromboplastin time, normalized by protamin neutralization in vitro, thus confirming the presence of a heparin-like anticoagulant. The hemostasis balance normalized after the specific treatment of lupus. CONCLUSION: This rare anomaly of hemostasis balance has been described in blood cancers and solid cancers. This is the first description of a case associated with an autoimmune connective tissue disorder such as lupus. After one year of follow-up, no diagnosis of blood or solid cancer was made.

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.

Sensitive fluorescence detection of heparin based on self-assembly of mesoporous silica nanoparticle-gold nanoclusters with emission enhancement characteristics.

Heparin (Hep) is widely used as a major anticoagulant in surgery. Simple and sensitive methods capable of quantitative detection of Hep are desired for better regulating its clinical use. Herein, a novel nanoassembly of amino-functionalized mesoporous silica nanoparticle-gold nanoclusters (MSN-AuNCs) with remarkable emission enhancement characteristics for sensitive fluorescence detection of Hep is developed. The electrostatic interaction between the positively charged amino-functionalized MSNs and the AuNC-stabilizing surface ligands triggers the self-assembly of MSN-AuNC nanocomposites which exhibit more than 5-fold fluorescence emission enhancement. However, the presence of negatively charged Hep inhibits the emission enhancement phenomenon due to the effective wrapping of Hep on the surface of MSNs, which blocks the interaction between AuNCs and MSNs. Benefitting from the remarkable emission enhancement and the competing binding of Hep, facile and ultrasensitive detection of Hep can be realized with a detection limit as low as 2 nM. Moreover, the successful application of the proposed method for detection of Hep in human serum samples shows promise for clinical applications.

Adenosine-Related Compounds as an Enhancer for Peroxidase-Mimicking Activity of Nanomaterials: Application to Sensing of Heparin Level in Human Plasma and Total Sulfate Glycosaminoglycan Content in Synthetic Cerebrospinal Fluid.

A variety of compounds, such as DNA and protein, have been demonstrated to be effective in suppressing the catalytic activity of peroxidase-like nanomaterials. However, little investigations have been conducted to discover new chemical compounds for amplifying the catalytic activity of peroxidase-mimicking nanomaterials. This study discloses that adenosine analogues were useful as a universal enhancer for peroxidase-mimicking nanomaterials in the hydrogen peroxide-mediated oxidation of amplex ultrared at neutral pH. The optimal adenosine analogues for improving the peroxidase-like performance of citrate-stabilized gold nanoparticles (Au NPs), citrate-capped platinum NPs, bovine serum albumin-encapsulated gold nanoclusters, and unmodified magnetite NPs were found to be adenosine diphosphate (ADP), ADP, ADP, and adenosine monophosphate, respectively. The results show that adenosine analogue-induced enhancement in the peroxidase-like activity of nanomaterials was heavily associated with the number of adsorbed adenosine analogues onto the nanomaterial surface. The analysis of ADP-modified Au NPs by electron paramagnetic resonance spectroscopy indicates that the adsorbed ADP molecules on the Au NP surface not only activated H2O2 but also strengthened the interaction between hydroxyl radicals and nanomaterials. By integrating the ADP-boosted catalytic activity of peroxidase-like Au NPs, surfen-triggered NP aggregation, and specific surfen-sulfated glycosaminoglycan (GAG) interaction, a turn-on fluorescent probe was constructed to quantify the heparin level in human plasma and total sulfate GAG content in synthetic cerebrospinal fluid.

Heparin-protamine balance after neonatal cardiopulmonary bypass surgery.

Essentials Heparin-protamine balance (HPB) modulates bleeding after neonatal cardiopulmonary bypass (CPB). HPB was examined in 44 neonates undergoing CPB. Post-operative bleeding occurred in 36% and heparin rebound in 73%. Thrombin-initiated fibrin clot kinetic assay and partial thromboplastin time best assessed HPB. SUMMARY: 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.