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Perovskite nanocrystals (NCs) feature adjustable bandgap, wide absorption range, and great color purity for robust perovskite optoelectronic applications. Nevertheless, the absence of lasting stability under continues energization, is still a major hurdle to the widespread use of NCs in commercial applications. In particular, the reactivity of red-emitting perovskites to environmental surroundings is more sensitive than that of their green counterparts. Here, we present a simple synthesis of ultrathin ZrO2coated, Sr2+doped CsPbBrI2NCs. Introducing divalent Sr2+may significantly eliminate Pb° surface traps, whereas ZrO2encapsulation greatly improves environmental stability. The photoluminescence quantum yield of the Sr2+-doped CsPbBrI2/ZrO2NCs was increased from 50.2% to 87.2% as a direct consequence of the efficient elimination of Pb° surface defects. Moreover, the thickness of the ZrO2thin coating gives remarkable heat resistance and improved water stability. Combining CsPbSr0.3BrI2/ZrO2NCs in a white light emitting diode (LED) with an excellent optical efficiency (100.08 lm W-1), high and a broad gamut 141% (NTSC) standard. This work offers a potential method to suppress Pb° traps by doping with Sr2+and improves the performance of perovskite NCs by ultrathin coating structured ZrO2, consequently enabling their applicability in commercial optical displays.
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Absorptive polarizers are pivotal components for realizing a low ambient reflection in liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs). Different types of absorptive polarizers have been proposed. Nevertheless, the realization of compact and efficient absorptive polarizers remains challenging. Wire grid polarizers (WGPs) are a promising solution because of their high durability and relatively thin thickness. In this paper, two structures of absorptive-WGPs have been proposed and optimized at the target wavelength of 532 nm: one is based on a patterned F e 2 O 3/A l bi-layer on top of a S i O 2 substrate, and the second one builds on the first one by depositing a S i O 2 layer in the gaps of Al. The optimal solutions exhibit a reflectance less than 5%, a transmittance over 45%, and an extinction ratio over 40 dB. To evaluate the manufacturing feasibility, their sensitivity to the wire's dimensional parameters is investigated. Their great spectral performance and large acceptance angles demonstrate that such polarizers have the potential to significantly promote the development of current display technologies.
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In this report, we successfully implement a unique cross-field beam deflector by exploiting the modulation of a one-dimensional refractive index in a copper-doped potassium tantalite niobite crystal. A theoretical model is established based on an electrostrictive effect regulated by the dynamic polarized nano-domains to explicate the mechanism of the abnormal beam deflection which is perpendicular to the applied electric field. Experimental results agree well with our theoretical deduction while validating the interactions between the dynamic polarized nano-domains and the applied electric field. Our findings will break the limitation of conventional electro-optic deflectors, paving the way to develop promising optical functional devices with a large field-of-view scanning angle and ultra-low driving voltage.
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In this work, we report the development of an external-cavity wavelength-swept amplified spontaneous emission (ASE) source with high output power and high tuning speed based on an efficient electro-optic effect of beam deflection. The wavelength-swept ASE source is capable of delivering stable output power with averaged intensity of 100 mW in a wide spectrum tuning range of over 80 nm around the wavelength of 1550 nm. The light source will have important applications in optical communications, biomedical imaging, spectral analysis and sensing.
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PURPOSE: This study aimed to investigate the correlation between cerebral microbleeds and carotid atherosclerosis in patients with ischemic stroke. SUBJECTS AND METHODS: Patients with ischemic stroke treated in a hospital in China from 2016 to 2017 were enrolled in the study. Based on the results from susceptibility-weighted imaging, the patients were divided into cerebral microbleed and noncerebral microbleed groups. The degree of carotid atherosclerosis was assessed with carotid intima-media thickness (CIMB) and Crouse score of carotid plaque. The details of patients' demographic information, cerebrovascular disease-related risk factors, carotid atherosclerosis indices, cerebral microbleed distribution, and grading were recorded, compared, and analyzed. RESULTS: Logistic regression analysis of the 198 patients showed that CIMB and Crouse score were significantly correlated with the occurrence of cerebral microbleeds. The CIMB thickening group (P = .03) and the plaque group (P = .01) were more susceptible to cerebral microbleeds. In the distribution of cerebral microbleed sites, Crouse scores were the highest in the mixed group and showed a statistically significant difference (P < .01). As the degree of carotid atherosclerosis increased, the average number of cerebral microbleeds also increased (P < .01). The receiver operating characteristic curve analysis of the carotid atherosclerosis indices showed a statistically significant difference. The CIMB value combined with the Crouse score was the best indicator (P < .01). CONCLUSION: In patients with ischemic stroke, cerebral microbleeds are closely related to carotid atherosclerosis. Active control of carotid atherosclerosis is important to prevent cerebral microbleeds in patients with ischemic stroke.
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Isquemia Encefálica/complicações , Doenças das Artérias Carótidas/complicações , Hemorragia Cerebral/complicações , Placa Aterosclerótica/complicações , Acidente Vascular Cerebral/complicações , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/epidemiologia , Doenças das Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/epidemiologia , Espessura Intima-Media Carotídea , Hemorragia Cerebral/diagnóstico por imagem , Hemorragia Cerebral/epidemiologia , Feminino , Humanos , Modelos Logísticos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/epidemiologia , Curva ROC , Fatores de Risco , Índice de Gravidade de Doença , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/epidemiologia , Ultrassonografia DopplerRESUMO
Retinal vein occlusion (RVO) is a common clinical disease causing vision loss. Risk factors such as diabetes, atherosclerosis are closely associated with RVO. Xuesaitong injection is used extensively in clinical treatment of RVO, however the mechanism is still unclear. In this study, we investigated the protective effect of Xuesaitong injection on RVO rat model. Using a compound-target network of Xuesaitong on anti-RVO constructed by literature mining, we aim to elucidate the multi-compound, multi-target effect of Xuesaitong injection. Fifteen potential targets of Xuesaitong injection associated with inflammation, angiogenesis, apoptosis, and coagulation were identified in this study. VEGF, IL-1beta and IL-6, three important targets in the compound-target network were further experimentally validated. This study provided experimental evidence for Xuesaitong injection being effective in treating RVO and a network view on its anti-RVO mode of action through a multi-compound and multiple-target mechanism.
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Medicamentos de Ervas Chinesas/administração & dosagem , Redes Reguladoras de Genes/efeitos dos fármacos , Oclusão da Veia Retiniana/tratamento farmacológico , Animais , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Oclusão da Veia Retiniana/genética , Oclusão da Veia Retiniana/metabolismoRESUMO
In this study, quasi-two-dimensional BixSn1-xO2 (BTO) thin films were fabricated using a liquid metal transfer method. The ultraviolet (UV) photodetector based on BTO thin films was constructed, and the ultrahigh responsivity of 589 A/W was observed at 300 nm UV light illumination. Interestingly, by dropping ethanol during light-off period, the recovery time induced by the persistent photoconductivity (PPC) effect is reduced from 1.65 × 103 s to 5.71 s. Furthermore, the recovery time can also be reduced by dropping methanol, propylene glycol, NaNO2, and Na2SO3 after light termination. The working mechanisms are attributed to the rapid consumption of holes stored in BTO thin films by reaction with those solutions. This work demonstrates that the BTO thin films have potential applications in high-performance UV detectors and present an innovation route to weaken the PPC effects in semiconductors by introducing chemical liquids on their surface.
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The Ti6Al4V alloy has been widely used in aerospace equipment and medical devices. However, the poor wear resistance of the Ti6Al4V alloy hinders its further engineering application. In this study, the ultrasonic strengthening grinding process (USGP) and laser texturing process were employed to enhance the wear resistance of Ti6Al4V alloy. The frictional behavior of all samples was determined via a ball-on-disc friction and wear tester under dry conditions. The worn surface morphology, cross-sectional hardness, surface roughness, and microstructure were analyzed. The results demonstrated that the USGP induced high hardness, high dislocation density, and grain refinement, as well as improvements in the wear resistance of Ti6Al4V. Moreover, laser texture could enhance the capacity to capture wear debris and reduce wear probability. When combining the USGP and laser texturing process for the surface treatment of Ti6Al4V alloy, the lowest and most stable friction coefficients were obtained, as well as the best wear resistance. Compared to the polished sample, the steady stage friction coefficient of the sample treated by USGP and laser texturing process was remarkably decreased by 58%. This work demonstrates that combining the USGP and laser texturing process could be a promising solution for improving the wear resistance properties of Ti6Al4V alloy, which makes it more suitable for various engineering applications.
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Selective laser melted (SLM) 316L stainless steel (SS) has been widely employed in the fields of designing and manufacturing components with complex shapes and sizes. However, the low yield strength, low ultimate tensile stress, and low hardness of SLM 316L SS components hinder its further application. In this work, the strengthening grinding process (SGP) was used to enhance the mechanical properties of SLM 316L SS. The microhardness, residual stress, microstructure, and tensile properties of all the samples were analyzed. The results demonstrate that the SGP induced higher compressive residual stress and microhardness, as well as higher tensile properties. The maximum hardness and residual stress reached 354.5 HV and -446 MPa, respectively, indicating that the SGP resulted in a plastic deformation layer over 150 µm. The possible mechanisms have been discussed in further detail. Compared to the untreated sample, the SGP sample shows a significant improvement in yield strength (YS), ultimate tensile stress (UTS), and elongation (EL), increasing 30%, 25.5%, and 99.1%, respectively. This work demonstrates that SGP treatment could be an efficient approach to simultaneously improving the strength and ductility of the SLM 316L SS, which makes it more suitable for engineering applications.
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In the present paper, the effect of mechanical ball milling time on the fretting wear of GCr15 steel balls at different displacement amplitudes is investigated. TiC powder coating was fabricated on the surface of GCr15 steel balls using various process times, and the fretting wear tests were conducted on an AISI 52100 steel disk with the applied force of 80 N. Additionally, various displacement amplitudes (10 µm, 20 µm, and 60 µm) were selected. Specimen attributes and wear scars were characterized using an inverted metallographic microscope, a microhardness tester, an X-ray diffractometry analyzer, a white light interferometer, and a scanning electron microscope. The results showed that thick and continuous coatings could be obtained at the milling time of 18 h. The specimens processed for a longer milling time demonstrated better fretting wear resistance, which we attribute to higher microhardness of the surface layer. The coefficient of friction and wear volume of specimens at each different displacement amplitude significantly decreased with increasing milling time. As the displacement amplitude increased, the three fretting states were: partial slip coordinated by elastic deformation; partial slip state coordinated by plastic deformation; and gross slip condition. Our observations indicate that mechanical ball milling could be an efficient approach to improve the fretting wear resistance of GCr15 steel balls.
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Introduction: Recombinant neorudin (EPR-hirudin, EH) was developed through the addition of an EPR (Glu-Pro-Arg) peptide to the amino terminus of hirudin, which can be recognized and cut by coagulation factors XIa (FXIa) and/or Xa (FXa). In this study, the low-bleeding antithrombotic effects of EH were evaluated utilizing experimental models of thrombosis in rabbits and rats to provide a test basis for clinical trials. Methods: The bleeding risks of EH and hirudin were first compared in mice by the tail-clipping method, and then the antithrombotic activity of EH was investigated in a rabbit model of arteriovenous bypass thrombosis and a rat model of thrombotic cerebral infarction. Results: In mice, intravenous administration of EH at 1.5 mg/kg and 3 mg/kg did not affect the bleeding time compared with normal saline, while the administration of hirudin at 1.5 mg/kg prolonged the bleeding time by over 3 times the administration of normal saline. Furthermore, intravenous administration of EH had a significant dose-dependent inhibitory effect on the formation and development of arteriovenous bypass thrombosis and thrombotic cerebral infarction. Compared with an equimolar dose of hirudin, the antithrombotic effect of EH was similar, while the bleeding side effects were significantly attenuated. Moreover, when the antithrombotic effects were similar, EH had a shorter bleeding time and was associated with less bleeding than low molecular weight heparin (LMWH). EH had a therapeutic effect on thrombotic cerebral infarction without increasing the occurrence of cerebral hemorrhage. Conclusion: The findings from the preclinical animal models used in this study showed that EH could not only effectively inhibit thrombus formation but also reduce the risk of bleeding.
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Hirudinas , Trombose , Animais , Infarto Cerebral/tratamento farmacológico , Fibrinolíticos/uso terapêutico , Hemorragia/tratamento farmacológico , Heparina de Baixo Peso Molecular/uso terapêutico , Hirudinas/farmacologia , Camundongos , Coelhos , Ratos , Proteínas Recombinantes , Solução Salina , Trombose/tratamento farmacológicoRESUMO
The anticoagulant application is an effective treatment modality for cardiovascular diseases such as coronary heart disease, unstable angina pectoris, and myocardial infarction. In this study, the antithrombotic effect of recombinant neorudin (EPR-hirudin, EH) was evaluated using a canine model of coronary artery thrombosis. A canine model with platelet thrombosis in the left circumferent branch of the coronary artery was designed using Folt's method, and the anti-thrombus activity of EH was investigated. Femoral administration of EH intravenously had a significant dose-dependent inhibitory effect on canine coronary artery thrombosis and the effective rates were 66.7% (p < .05), 83.3% (p < .05), and 100% (p < .01) after injection of 0.3, 1.0, and 3.0 mg/kg EH, respectively. Furthermore, EH demonstrated lower bleeding, with shorter bleeding time and less bleeding loss than low molecular weight heparin (LMWH). Under the similar effect intensity of EH and LMWH (85 IU/kg), the bleeding time of the EH group at 30 min was shorter, and the blood loss at 30-120 min was less than that of LMWH (p < .05 and p < .05-.001, respectively). EH had a significant dose-dependent inhibitory effect in the dose range of 0.3-3.0 mg/kg on the coronary artery thrombosis and lower bleeding side effects than LMWH with a similar antithrombosis effect.
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Trombose Coronária , Infarto do Miocárdio , Animais , Trombose Coronária/tratamento farmacológico , Vasos Coronários , Cães , Hemorragia/induzido quimicamente , Hemorragia/tratamento farmacológico , Heparina de Baixo Peso Molecular/uso terapêutico , Infarto do Miocárdio/tratamento farmacológicoRESUMO
BACKGROUND: Crops grown in soils contaminated by heavy metals are an important avenue for toxic metals entering the human food chain. The objectives of our study were to investigate the accumulation and distribution of cadmium (Cd) and lead (Pb) in wheat plants cultivated in arid soils spiked with different doses of heavy metal, as well as bioavailability of these metals in the contaminated arid soils from the oasis, north-west China. RESULTS: The concentrations of Cd in the roots of wheat plants were about 5, 14 and 8 times higher than those in the shoots, shells and grains, respectively. The concentrations of Pb in the roots were about 23, 76 and 683 times higher than those in the shoots, shells and grains, respectively. Grains contained 11-14% and 0.1-0.2% of Cd and Pb found in roots of wheat plants. The bioconcentration factor (BCF) is the ratio of metal concentration in plant tissues and metal concentration in their rooted soils. The average BCF of Cd and Pb in grains was 0.6270 and 0.0007. Cd and Pb contents in different parts of wheat plants mainly correlated with the bound-to-carbonate metal fractions in contaminated arid soils. CONCLUSION: The preliminary study indicated that Cd and Pb were predominantly accumulated and distributed in wheat roots and shoots, and only a small proportion of these metals can reach the grains. The carbonate fractions mainly contributed to Cd and Pb bioavailability in contaminated arid soils.
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Cádmio/metabolismo , Grão Comestível/metabolismo , Chumbo/metabolismo , Estruturas Vegetais/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Triticum/metabolismo , Disponibilidade Biológica , Carbonatos/metabolismo , China , Cadeia Alimentar , Contaminação de AlimentosRESUMO
[This corrects the article DOI: 10.1016/j.chmed.2019.12.005.].
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[This corrects the article DOI: 10.1016/j.chmed.2018.12.002.].
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Objective: To investigate the therapeutic effect of total iridoid glycosides of Picrorhiza scrophulariiflora (TIGP) on non-alcoholic steatohepatitis (NASH). Methods: SD rats were fed with high-fat and high-sugar diet for 8 weeks to establish NASH. TIGP were given orally at doses of 20, 40 and 80 mg/kg/d for 4 weeks. Triglycerides assay (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT), fasting plasma glucose (FPG), fasting insulin (FINS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), chemokine-1 (MCP-1), leptin (LEP) in serum were tested. TG, TC, superoxide dismutase (SOD), malondialdehyde (MDA), and free fatty acid (FFA) in liver tissue were determined by colorimetric methods. Steatosis of hepatocytes and inflammation was performed by pathological examination. Results: The results showed that TIGP significantly decreased TC, TG and FFA in liver tissue, increased SOD activity, decreased MDA content, decreased serum levels of TG, TC, HDL-C/LDL-C, ALT, AST, GLU, HOMA-IR, TNF-α and LEP, and in addition, improved steatosis of liver cells compared to NASH. Conclusion: TIGP had anti-fatty liver effect against NASH rats induced by high-fat and high-sugar diet. Its mechanism was related to the regulation of lipid metabolism and reduction of insulin resistance, through inhibition of oxidative stress and inflammation.
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Objectives: To investigate the thrombolysis with recombinant human prourokinase (rhPro-UK) on thromboembolic stroke in rats at different therapeutic time windows (TTW). Methods: Rats were subjected to embolic middle cerebral artery occlusion. RhPro-UK and positive control drugs rt-PA,UK were administered 3 h, 4.5 h, 6 h after inducing thromboem-bolic stroke. Neurological deficit scoring (NDS) was evaluated at 6 h and 24 h after the treatment. The lesion volume in cerebral hemispheres was measured by MRI scanning machine after 6 h of thrombolysis, and the infarct volume was measured by TTC stain, together with hemorrhagic volume quantified by a spectrophotometric assay after 24 h of thrombolysis. Results: RhPro-UK 10, 20 × 104 U/kg significantly improved the NDS after cerebral thromboembolism in rats at 3 h, 4.5 h TTW, and at the 6 h TTW, the NDS was improved by 28.0% (P = 0.0690) and 29.2% (P = 0.0927) at 6 h and 24 h after rhPro-UK 20 ×104 U/kg administration, respectively. RhPro-UK 10, 20 × 104 U/kg significantly reduced the brain lesions measured by MRI at 3 h and 4.5 h TTW. RhPro-UK 10, 20 × 104 U/kg significantly reduced the cerebral infarction measured by TTC at 3 h, 4.5 h TTW. There was no increase in cerebral hemorrhage compared with untreated group after rhPro-UK administration. Conclusions: RhPro-UK had an obvious therapeutic effect on ischemic stroke caused by thrombosis, and could be started within 4.5 h TTW with less side effects of cerebral hemorrhage than that of UK.
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Hemorragia Cerebral/tratamento farmacológico , Embolia Intracraniana/tratamento farmacológico , Acidente Vascular Cerebral/tratamento farmacológico , Ativador de Plasminogênio Tecidual/farmacologia , Animais , Hemorragia Cerebral/patologia , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/tratamento farmacológico , Embolia Intracraniana/complicações , Masculino , Ratos Sprague-Dawley , Acidente Vascular Cerebral/complicações , Tromboembolia/complicações , Tromboembolia/tratamento farmacológico , Terapia Trombolítica/métodos , Fatores de TempoRESUMO
In this report, an abnormal optical anisotropy in KTa1-xNbxO3:Cu (Cu:KTN) crystals with refractive index gradient is presented. Contrary to general regulation in a cross-polarization setup, the transmitted intensity of both TE (horizontally polarized) and TM (vertically polarized) lasers aligned with the basic crystallographic directions can be modulated quasiperiodically. The mechanism is supposed to be based on the polarization induced by the temperature gradient and the refractive index gradient. Meanwhile, the correlated disorder property of the crystals in the range of the freezing temperature (Tf) and the intermediate temperature (T *) also plays an important role. With the results verified both theoretically and experimentally, we believe this work is not only beneficial for the development of the theory associated with the correlated disorder structures in relaxor ferroelectrics, but also significant for the exploitation of numerous optical functional devices.
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We evaluated the efficacy and safety of human recombinant prourokinase ( rhpro-UK) on thromboembolic stroke in rats. 60 rats with thromboembolic stroke were divided into 6 groups (n = 10). The model group was given saline, the reagent groups were given rhpro-UK (5, 10, 20 × 104U/kg), and positive control groups were given urokinase (UK) 10 × 104U/kg and recombinant tissue plasminogen activator (rt-PA) 9mg/kg through intravenous infusion at 1.5h after embolism. And other 10 rats without occluded by autologous blood clots as the sham group were given saline. At 6h after treatment, neurological deficit score and Magnetic Resonance Imaging(MRI) including T1WI and T2WI sequence scanning were measured. At 24h after treatment, the brain was cut for 2,3,5-triphenyltetrazolium chloride (TTC) staining and aspectrophotometric assay to measure the infarct area and intracerebral hemorrhage after neurological deficit detection. rhpro-UK (5, 10, 20 × 104 U/kg) improved neurological disorder by 39.1 ± 19.7% (n = 10, P > 0.05), 65.2 ± 14.2% (n = 10, P < 0.01) and 65.2 ± 14.2% (n = 10, P < 0.01) maximally; decreased brain lesion volume by 36.7 ± 34.8% (n = 10, P < 0.05), 77.6 ± 7.7% (n = 10, P < 0.01) and 80.5 ± 6.9% (n = 10, P < 0.01); decreased infarction area by 38.2 ± 24.0% (n = 10, P < 0.01), 73.9 ± 5.2% (n = 10, P < 0.001) and 79.7 ± 4.0% (n = 10, P < 0.001) respectively, and there were no statistics difference between rhpro-UK (5, 10, 20 × 104 U/kg) and each positive groups at intracerebral hemorrhage (P > 0.05). Rhpro-UK improved the damaged neural function, decreased the extent of the disease and did not raise bleeding, had protective effects for cerebral ischemia in rats.
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Precursores Enzimáticos/farmacologia , Proteínas Recombinantes/farmacologia , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/tratamento farmacológico , Tromboembolia/complicações , Ativador de Plasminogênio Tipo Uroquinase/farmacologia , Animais , Hemorragia Cerebral/complicações , Precursores Enzimáticos/uso terapêutico , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/uso terapêutico , Acidente Vascular Cerebral/patologia , Ativador de Plasminogênio Tipo Uroquinase/uso terapêuticoRESUMO
The development of thrombolytic agent could provide invaluable progress for antithrombotic therapy. In this paper, we reported the cloning, purification and biochemical characterization of AnxB1ScuPAFap, a thrombus-ditargeting chimera composed of annexin B1, low molecular single-chain urokinase (ScuPA-32K) and fibrin-adherent peptide (dodecapeptide, Fap). In vitro test showed that, the chimera was a thrombolytic agent with anticoagulant activity and thrombus-ditargeting with the activated-platelet membrane binding and fibrin clot binding activity. Compared to urokinase, the chimera had less reperfusion time, higher reperfusion ratio, and less bleeding effects on coronary thrombolysis by clot lysis assay in dogs. Thus, the chimera appeared to be suitable for thrombolytic therapy of thrombus diseases.