BACKGROUNDDue to lack of point-of-care testing, the use of low-molecular-weight heparin (LMWH) therapy in some special patients is restricted. This study was designed to explore the effects of LMWH on clot rate (CR) and activated clotting time (ACT), and to search for an appropriate method for bedside monitoring of anticoagulant activity of LMWH.

METHODSThirty-two healthy volunteers were selected from the staff of Beijing Tongren Hospital. CR and ACT were measured with different reagents (glass beads, diatomite, kaolin and magnetic bar) on blood samples spiked with increasing concentrations of LMWH (dalteparin, 0.2-1.8 IU/ml). Correlations between concentrations of LMWH and values of CR and ACT were analysed based on the data obtained and regression analysis was performed to establish a regression equation.

RESULTSWith the increase in doses of dalteparin, CR values reduced gradually. The values of CR of four reagents (glass beads, diatomite, kaolin and magnetic bar) were 20.4-4.5 IU/min, 27.4-6.9 IU/min, 27.5-7.9 IU/min and 7.8-0.1 IU/min respectively and an linear relationship was observed between the CR values and dalteparin concentrations (P < 0.05). The values of ACT were 173-615 seconds, 130-270 seconds, 123-226 seconds, 337-1411 seconds respectively, which showed a linear regression between the ACT values and dalteparin concentrations (P < 0.01). Differences in slope of the regression curves of ACT were observed with all the reagents tested (glass beads 248.2 s/IU, diatomite 74.8 s/IU, kaolin 58.2 s/IU and magnetic bar 1112.2 s/IU, P < 0.01). While the minimum concentration of dalteparin was 0.2 IU/ml, 0.4 IU/ml, 1.4 IU/ml and 0.2 IU/ml separately, the ACT values of the four coagulants (glass beads, diatomite, kaolin and magnetic bar) were beyond the normal limit and showed a noticeable increase respectively (P < 0.01).

CONCLUSIONSThis study showed that there was an excellent linear relationship between the CR and ACT values and dalteparin concentrations for all the four reagents (glass beads, diatomite, kaolin and magnetic bar) in vitro. The sensitivity of different coagulation reagents to LMWH different. Choosing a suitable reagent, both CR and ACT were possible to be used as a convenient bedside test for LMWH.

Adult ; Anticoagulants ; pharmacology ; Blood Coagulation ; drug effects ; Blood Coagulation Tests ; Female ; Heparin, Low-Molecular-Weight ; pharmacology ; Humans ; Male ; Middle Aged

OBJECTIVETo evaluate the anticoagulant and antineoplastic activities of chemically modified low-molecular-weight heparin (LMWH).

METHODSLMWH obtained by splitting unfractionated heparin (UFH) with sodium periodate oxidation and sodium borohydride reduction was subjected to acetylation catalyzed by DCC and DMAP to produce acetylated LMWH (ALMWH). The anticoagulant activity of ALMWH was determined in mice, and its antiproliferative and anti-invasion activities was assessed in human breast cancer cells MDA-MB-231 and MFC-7.

RESULTSThe anticoagulant activity of LMWH was decreased significantly after acetylation. The concentrations of commercial LMWH* and ALMWH for doubling the coagulation time (CT) were 33.04 µmol/L and 223.56 µmol/L, respectively, and the IC(50) of ALMWH for doubling CT was 6 times of that of LMWH*. ALMWH and LMWH at 0.1, 0.3, 0.9, 2.7 and 8.1 mmol/L both significantly inhibited the proliferation of MDA-MB-231 and MCF-7 cells in a concentration-dependent manner, but ALMWH produced stronger inhibitory effects. The IC(50) of LMWH and ALMWH for inhibiting cell proliferation was 3168.4 µmol/L and 152.6 µmol/L in MCF-7 cells, and 12299.6 µmol/L and 22.2 µmol/L in MDA-MB-231 cells, respectively. ALMWH and LMWH all markedly suppressed the invasion of MDA-MB-231 cells with comparable effects.

CONCLUSIONChemical modification of structure can endow LMWH with a low anticoagulant and high antiproliferative activities.

Animals ; Anticoagulants ; chemistry ; pharmacology ; Antineoplastic Agents ; chemistry ; pharmacology ; Blood Coagulation ; Blood Coagulation Tests ; Cell Line, Tumor ; Heparin ; chemistry ; Heparin, Low-Molecular-Weight ; chemistry ; pharmacology ; Humans ; Mice

BACKGROUNDAlthough low-molecular-weight heparin has replaced unfractionated heparin to become the primary anticoagulation drug for treatment of acute coronary syndrome, there is no convenient bedside monitoring method. We explored the best laboratory monitoring method of low-molecular-weight heparins (enoxaparin, dalteparin, and nadroparin) by use of the Sonoclot coagulation analyzer to monitor the activated clotting time.

METHODSA total of 20 healthy volunteers were selected and 15 ml of fasting venous blood samples were collected and incubated. Four coagulants, kaolin, diatomite, glass bead, and magnetic stick, were used to determine the activated clotting time of the low-molecular-weight heparins at different in vitro anti-Xa factor concentrations. A correlation analysis was made to obtain the regression equation. The activated clotting time of the different low-molecular-weight heparins with the same anti-Xa factor concentration was monitored when the coagulant glass beads were applied.

RESULTSThe activated clotting time measured using the glass beads, diatomite, kaolin, and magnetic stick showed a linear correlation with the concentration of nadroparin (r = 0.964, 0.966, 0.970, and 0.947, respectively). The regression equation showed that the linear slopes of different coagulants were significantly different (glass beads 230.03 s/IU, diatomite 89.91 s/IU, kaolin 50.87 s/IU, magnetic stick could not be calculated). When the concentration of the anti-Xa factor was the same for different low-molecular-weight heparins, the measured activated clotting time was different after the application of the glass bead coagulant.

CONCLUSIONSThe glass bead coagulant is most feasible for monitoring the in vitro anticoagulation activity of nadroparin. The different effects of different low-molecular-weight heparins on the activated clotting time may be related to the different anti-IIa activities.

Adult ; Anticoagulants ; pharmacology ; Blood Coagulation ; drug effects ; Blood Coagulation Tests ; Coagulants ; pharmacology ; Female ; Glass ; Heparin, Low-Molecular-Weight ; pharmacology ; Humans ; Kaolin ; pharmacology ; Male ; Middle Aged ; Nadroparin ; pharmacology

Based on non-enzymatic protein glycated reaction, the sodium periodate-oxidated low molecular weight heparin-antithrombin covalent complex (SPLMWATH) was produced. By using polyethyleneimine-glutaraldehyde bonding technique, polyvinyl chloride (PVC) tubings were coated with SPLMWATH, heparin and low molecular weight heparin (LMWH). Spectrophotometry and dynamic clotting time experiment were used to determine the synthetic ratio of SPLMWATH, graft density, coating leaching ratio and to evaluate the antithrombogenicity of different coating on the PVC tubings. The results showed that the synthetic ratio of SPLMWATH was approximately 55%, and compared with heparin coating and LMWH coating, the graft density of SPLMWATH coating on the PVC tubing was smaller, but its coating stability and antithrombogenicity were significantly better than that of heparin coating and LMWH coating on the PVC tubings.
Anticoagulants ; chemical synthesis ; pharmacology ; Coated Materials, Biocompatible ; chemical synthesis ; pharmacology ; Extracorporeal Circulation ; instrumentation ; Heparin, Low-Molecular-Weight ; chemistry ; pharmacology ; Humans ; Polyvinyl Chloride ; chemistry ; Surface Properties

OBJECTIVETo study the effects of low-molecular weight heparin (LMWH) and adrenocortical hormone (dexamethasone) on the hemolysis of red cells of patients with paroxysmal nocturnal hemoglobinuria (PNH) in vitro.

METHODSUsing Ham's test and micro-complement lysis sensitive test (mCLST), the changes in hemolysis of red cells from 6 typical PNH cases were examined after adding LMWH and dexamethasone in different concentrations into the test solution in vitro. The effects of LMWH and dexamethasone on the coagulation of the tested blood samples were also studied using the activated partial thromboplastin time (APTT) test.

RESULTSBoth LMWH and dexamethasone inhibited the hemolysis of PNH red cells, and they also showed a synergistic effect. The inhibiting effects were dose-dependent. Moreover, a tolerable dose of LMWH induced a limited prolongation of APTT. Dexamethasone showed two possible mechanisms in the inhibition of PNH red cells hemolysis through Ham's test and mCLST, respectively: (1) inhibiting both antibodies binding to red cells and (2) the initiation of the activation of complement 3 (C3). LMWH could inhibit hemolysis as determined by both Ham's test and mCLST, which indicated that LMWH could block the activation of complement cascade.

CONCLUSIONSBoth LMWH and dexamethasone could inhibit hemolysis in PNH, and they showed a synergistic effect. Their mechanisms of inhibiting hemolysis differed from each other. Furthermore, a tolerable dose of LMWH induced a limited prolongation of APTT. LMWH might be useful for controlling acute hemolysis in patients with PNH and reducing the dose of adrenocortical hormone.

Dexamethasone ; pharmacology ; Dose-Response Relationship, Drug ; Hemoglobinuria, Paroxysmal ; blood ; drug therapy ; Hemolysis ; drug effects ; Heparin, Low-Molecular-Weight ; pharmacology ; Humans ; Partial Thromboplastin Time

PURPOSE: Postoperative adhesion is the most frequent complication of abdominal surgery. Therefore, we investigated the individual effects of synthetic barrier [hyaluronic acid/carboxymethylcellulose (HA/CMC)] and pharmacologic agents [low molecular weight heparin (LMWH) cyclo-oxygenase-2 inhibitor (COX-2 inhibitor)] using animal model of intra-abdominal adhesion. MATERIALS AND METHODS: The cecum was rubbed with sterile alcohol wet gauze until subserosal haemorrhage and punctate bleeding developed under the general anesthesia. Five animal groups were prepared using the film HA/CMC, gel HA/CMC, LMWH and COX-2 inhibitor. RESULTS: The grade of adhesion by modified Leach method for group I (control), II (film type HA/CMC), III (gel type HA/CMC), IV (LMWH) and V (COX-2 inhibitor) were 5.35+/-1.8, 6.15+/-1.3, 4.23+/-2.6, 5.05+/-0.7 and 5.50+/-0.9, respectively. Group III showed the least grade of adhesion and it is statistically significant in adhesion formation (p=0.028). The numbers of lymphocytes were significantly low in group III and group V compared to the control group (lymphocyte: p=0.004). The mast cell counts were generally low except for the control group (I: 1.05, II: 0.35, III: 0.38, IV: 0.20, V: 0.37), however, it was not statistically significant (p=0.066). CONCLUSION: The gel barriers were shown to be partly efficient in inhibiting the formation of postoperative adhesions and might provide an option for abdominal surgery to reduce postoperative adhesions. The LMWH and COX-2 inhibitor had been known for their inhibitor effect of fibrin formation and anti-angiogenic/anti-fibroblastic activity, respectively. However, their preventive effects of adhesion and fibrosis were found to be obscure.
Animals ; Carboxymethylcellulose Sodium/metabolism ; Cyclooxygenase 2 Inhibitors/*pharmacology ; Heparin, Low-Molecular-Weight/*pharmacology ; Male ; Rats ; Rats, Sprague-Dawley ; Tissue Adhesions/*prevention & control

OBJECTIVETo establish the rat model of acute pulmonary embolism, and study the changes of vascular active substances in pulmonary embolism rats, and investigate the interventive effect of anticoagulant drugs on vascular active substances.

METHODSOne hundred and twenty-eight rats were randomly divided into four groups: control group, model group, low-molecular-weight heparin and warfarin treated group and rivaroxaban-treated group (n = 32 in each group). The method of autologous thrombosis was used to establish the animal model of acute pulmonary embolism. The animals were treated with saline or different anticoagulant drugs. The physiological and biochemical parameters were detected at different time points after embolization. The rats were killed after embolism of 24 h, 3 d, 5 d or 1 week respectively and the pathologic samples of lung tissues were collected to analyze the pulmonary pathological changes in different groups.

RESULTSRats in embolization group after blood clots injection showed shortness of breath, oral cyanosis; quicken heart rates and other symptoms. All embolization groups had pulmonary hypertension, the levels of type B natriuretic peptide (BNP) were increased significantly. The ratio of endothelin-1 (ET-1)/NO and thromboxane (TXB2) and prostacyclin (6-k-PGFla) were abnormal. After treated with effective anticoagulant drugs, the levels of BNP, ET-1, NO, TXB2 and 6-k-PGF1a were tended to the normal levels in the control group. The pulmonary hypertensions were gradually decreased. The efficacy of rivaroxaban on pulmonary embolism was the same as that of the low molecular weight heparin or warfarin.

CONCLUSIONAnticoagulation therapy can effectively improve endothelial function after pulmonary embolism, reduce pulmonary hypertension, and revise the increased BNP levels to normal levels. The efficacy of rivaroxaban is not inferior to that of low molecular weight heparin and warfarin.

Animals ; Anticoagulants ; pharmacology ; Disease Models, Animal ; Endothelin-1 ; metabolism ; Heparin, Low-Molecular-Weight ; pharmacology ; Hypertension, Pulmonary ; drug therapy ; metabolism ; Lung ; pathology ; Morpholines ; pharmacology ; Pulmonary Embolism ; drug therapy ; metabolism ; Rats ; Rivaroxaban ; Thiophenes ; pharmacology ; Warfarin ; pharmacology

OBJECTIVETo study the in vitro effects of low-molecular weight heparin (LMWH) and dexamethasone on the hemolysis of red blood cells from paroxysmal nocturnal hemoglobinuria (PNH) patients.

METHODSBy Ham's test and micro-complement lysis sensitive test (mCLST), the changes of hemolysis of red blood cells from 6 PNH patients were tested by adding different doses of LMWH and dexamethasone into the test mixture. The effects of LMWH and dexamethasone on the coagulation of the tested blood samples were also studied by activated partial thromboplastin time (APTT).

RESULTS(1) Either LMWH or dexamethasone could dose-dependently inhibit the hemolysis of PNH red blood cells, and the effects were synergistic when added together. The same dose of LMWH induced a less than 100% prolongation of APTT. (2) Dexamethasone could inhibit the hemolysis in Ham's test and had different effects on the hemolysis by different adding methods in mCLST. LMWH could inhibit the hemolysis in both Ham's test and mCLST.

CONCLUSIONBoth LMWH and dexamethasone could inhibit the hemolysis of PNH red cells and showed a synergistic effect. The mechanisms of the inhibition of hemolysis were different. Furthermore, a tolerable dose of LMWH induced only a limited prolongation of APTT, which might be useful for controlling acute hemolysis and reducing the dose of dexamethasone.

Anti-Inflammatory Agents ; pharmacology ; Dexamethasone ; pharmacology ; Dose-Response Relationship, Drug ; Erythrocytes ; cytology ; drug effects ; Hemoglobinuria, Paroxysmal ; blood ; Hemolysis ; drug effects ; Heparin, Low-Molecular-Weight ; pharmacology ; Humans ; Partial Thromboplastin Time

BACKGROUND: The incidence of pulmonary embolism (PE) in lung cancer patients who underwent surgery increased during the perioperative period, and prophylactic anticoagulation therapy was important part of enhanced recovery after surgery (ERAS). However, the timing of preventive anticoagulation in patients with lung cancer remained controversial. This study was designed to investigate the safety and efficacy of perioperative prophylactic anticoagulation therapy for lung cancer patients. METHODS: Retrospective research was conducted on 562 lung cancer patients who underwent video-assisted thoracoscopic (VATS) anatomic pulmonary resections in West China Hospital from June 2016 to December 2016. 56 patients were treated with low molecular weight heparin (LMWH) anticoagulation 12 hours before operation until discharge, while the other 506 patients were treated with LMWH 24 hours after operation until discharge. The postoperative chest drainage volume, postoperative bleeding, pulmonary embolism incidence, and respiratory complications were analyzed. RESULTS: (1) There were no significant differences in prothrombin time (PT), activated partial thromboplastin time (APTT) and international normalized ratio (INR) between the pre-operation prophylactic anticoagulation group (PRE group) [(11.5±3.9) s, (27.8±3.5) s, (0.96±0.06) s] and the post-operation prophylactic anticoagulation group (POST group) [(11.4±1.4) s, (28.3±4.0) s, (0.98±0.07) s] (P=0.796, P=0.250, P=0.137), and there was no significant difference in Caprini score between the PRE group (3.1±1.8) and the POST group (3.3±1.5) (P=0.104). (2) There were no significant differences in anesthesia time and intraoperative bleeding between PRE group [(130.2±53.9) min, (76.8±49.3) mL] and POST group [(142.2±56.5) min, (73.7±41.6) mL] (P=0.067, P=0.201). (3) The total drainage volume in 72 hours after operation in PRE group [(728.1±505.7) mL] was significantly higher than that of POST group [(596.4±373.5) mL] (P=0.005), while there were no significant differences between the two groups in total postoperative drainage volume [(1,066.8±1,314.6) mL vs (907.8±999.8) mL, P=0.203]. (4) There were no significant differences between the two groups in pulmonary embolism incidence (1.785% vs 0.019%, P=0.525) and postoperative bleeding rates (1.785% vs 0.039%, P=0.300). (5) There were no significant differences between PRE group and POST group in subcutaneous emphysema incidence (1.785% vs 1.581%, P=0.989) and pulmonary infection rates (14.285% vs 6.324%, P=0.085). CONCLUSIONS The clinical value of preoperative prophylactic anticoagulation is equal to postoperative prophylactic anticoagulation for lung cancer patients.
Adult ; Aged ; Anticoagulants ; pharmacology ; Female ; Heparin, Low-Molecular-Weight ; pharmacology ; Humans ; Lung Neoplasms ; surgery ; Male ; Middle Aged ; Perioperative Period ; Postoperative Complications ; etiology ; prevention & control ; Retrospective Studies ; Safety ; Young Adult

OBJECTIVETo investigate the anti-apoptotic effect of low molecular weight heparin (LMWH) in the placenta of rats with preeclampsia-like symptoms.

METHODSThirty pregnant Wistar rats were randomized equally into 3 groups and received subcutaneous saline injection (control group), 200 mg/kg L-NAME injection to induce preeclampsia symptoms (PE group), or L-NAME with 40 µl/kg LMWH injections (LMWH group). The blood pressure, urine protein, the number of pups and the weight of the fetuses and placenta were measured, and the placental apoptotic index was measured by TUNEL assay. The expression of cleaved caspase-3, Bcl-2 and Bax in the placenta were examined by Western blotting.

RESULTSCompared with the control group, L-NAME injections caused significantly increased blood pressure and urine protein (P<0.05), which were significantly lowered by LWMH (P<0.05). The number and weight of normal pups were significantly lower in PE group than in the control group (P<0.05) and LMWH group (P<0.05); in LMWH group, the weight of pups was still lower than that of the control group (P<0.05) but the number of normal pups was comparable (P>0.05). The LMWH group showed a significantly lower placental apoptosis index than the PE group (P<0.05) with also significantly lower cleaved caspase-3 and Bax and higher Bcl-2 expressions (P<0.05). The apoptosis index and expressions of cleaved caspase-3, Bcl-2 and Bax protein were similar between LMWH group and normal pregnant group (P>0.05).

CONCLUSIONLMWH can alleviate preeclampsia-like symptoms and decrease the apoptosis in the placenta of rats possibly by enhancing Bcl-2 and suppressing Bax expressions.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Female ; Heparin, Low-Molecular-Weight ; pharmacology ; Placenta ; cytology ; Pre-Eclampsia ; pathology ; Pregnancy ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Wistar ; bcl-2-Associated X Protein ; metabolism