Results 1 - 10 of 474
Results 1 - 10 of 474. Search took: 0.022 seconds
|Sort by: date | relevance|
[en] Highlights: • A triboelectric biosensor is developed for the self-powered detection of thrombin. • The selective recognition of thrombin is achieved by using aptamer. • The change in the electrical output upon sensing is resulted from the changes in the surface potential. • The triboelectric biosensor achieves a high detection sensitivity of 0.41 nM. • Thrombin detection is also directly demonstrated via an array of LED lights. An aptamer-based triboelectric biosensor is developed for a highly specific, label-free and self-powered detection of thrombin. For the first time, intermolecular recognition interactions are used to develop a selective nanosensor based on triboelectric effect. Positively charged Au nanoparticles (Au NPs+) with large difference in triboelectric polarity and work function are assembled onto Al film to increase the electrical output of triboelectric nanogenerators (TENG). Modification of anti-thrombin aptamers on the Au NPs+-assembled TENG affords the triboelectric nanosensor highly selective toward thrombin, even in clinical samples because of specific binding affinity between aptamers and thrombin unlike random DNA-modified TENGs with undetectable response. A 0.41 nM limit of detection is achieved, which is directly demonstrated by the number of commercial LED lights without any supporting equipment such as power source and electrometer. Our study demonstrates an innovative and unique approach toward the self-powered and label-free detection of thrombin for rapid and simple in-field analysis.
[en] Massive hemoptysis caused by pulmonary artery pseudoaneurysms is uncommon, and endovascular treatment such as coil embolization is the first choice for treating pulmonary artery pseudoaneurysms. Various embolic agents could be used according to the angiographic findings, yet embolization with thrombin injection is very rare. Herein, we describe a case of a pulmonary artery pseudoaneurysm that was successfully treated by endovascular thrombin injection using a microcatheter because of the difficulty in performing a coil embolization due to a short feeding artery.
[en] A method for fluorescent sensing of thrombin was developed by using fluorescent silica nanoparticles as the fluorescence signal probes and magnetic beads as target enriching platform. RuBpy-doped silica nanoparticles are highly photostable and provide significant fluorescent signal amplification as compared with single dye molecules. TBA1 is a 15-mer DNA aptamer which binds exosite I of thrombin (Fibrinogen Binding Site), while TBA2 is a 29-mer DNA aptamer binding to exosite II of thrombin (Heparin Binding Domain). In this work, 15-mer thrombin-binding aptamer (15-A) was immobilized onto the surface of RuBpy-doped silica nanoparticles, and 29-mer thrombin-binding aptamer (29-A) was immobilized onto the surface of magnetic beads, and sandwich aptamer complexes were formed upon the addition of target thrombin molecules with the two kinds of aptamer-modified particles, and therefore quantitative analysis of thrombin was performed by detecting the fluorescence intensity of the complexes after magnetic separation of the targets. The results show that the detection limit of thrombin is 0.70 nM, and this method has some advantages such as speed, high sensitivity, high specificity and low cost.
[en] A pseudoaneurysm of the superior mesenteric artery (SMA) is a rare and life-threatening condition of various etiology. Even unruptured it can cause severe health problems or death. We report a 71-year-old male with a SMA pseudoaneurysm who was successfully treated with a transarterial thrombin injection secured with an embolic protection device used in carotid angioplasty. To our knowledge, this is the first case of a SMA pseudoaneurysm treated by this method.
[en] Highlights: • High resolution respirometry can be used to investigate the rapid kinetics of changes in platelet oxygen consumption rate. • Thrombin triggers a rapid, transient increase in platelet oxygen consumption rate. • Aspirin and oligomycin partially inhibit the increased oxygen consumption rate. Platelet activation plays a key role in normal haemostasis and pathological thrombosis. Platelet activation is rapid; within minutes of stimulation, platelets generate bioactive phospholipids, secrete their granule contents, activate integrins and aggregate together to form a haemostatic plug. These events are dependent on ATP synthesis. Mitochondrial function in platelets from healthy volunteers and patients with a range of diseases indicate an important role for oxygen consumption in oxidative phosphorylation in normal and pathological function. Platelets also consume oxygen during oxidation reactions, such as cyclooxygenase-dependent thromboxane A2 synthesis. In this study, we used high-resolution respirometry to investigate rapid changes in oxygen consumption during platelet activation. We demonstrated a rapid, transient increase in oxygen consumption rate within minutes of platelet stimulation by the physiological activator, thrombin. This was partly inhibited by aspirin and by oligomycin. This shows that high resolution respirometry can provide information regarding rapid and dynamic changes in oxygen consumption during platelet activation.
[en] Deep vein thrombosis (DVT) is a serious medical condition that needs prompt diagnosis and treatment. The invasive gold standard contrast venography has largely been replaced by venous ultrasonography which is currently the imaging modality of choice for DVT diagnosis. Radionuclide venography (RNV) is an alternative test for DVT, but a few studies have directly compared RNV with venous ultrasonography. This study aims to determine the agreement between RNV and venous ultrasonography for diagnosis of DVT and to determine the predictive value of different RNV findings for the prediction of DVT as detected by venous ultrasonography. Imaging results from patients who underwent both RNV and venous ultrasonography for suspected DVT no more than 1 week apart were reviewed. Results from both modalities were compared to determine inter-modality agreement. A total of 121 venous segments from 102 lower limbs of 75 patients could be compared. The prevalence of DVT as detected by venous ultrasonography was 39%. RNV and venous ultrasonography had moderate agreement (73.6% agreement, κ =0.48, P < 0.0001). The absence of radiotracer activity from a deep venous segment had a positive predictive value (PPV) of 100% for DVT. Other findings such as isolated great saphenous vein activity had a lower PPV. The negative predictive value of RNV is 97.5% with only one patient out of forty with normal RNV found to have DVT by venous ultrasonography, which suggests that DVT can virtually be excluded in patients with normal RNV.
[en] Pseudoaneurysms of the inferior gluteal artery (IGA) are rare and are often caused by trauma. Treatment options vary and include surgery, ultrasound-guided percutaneous thrombin injection, and endovascular procedures such as stent-graft placement, coil embolization, and glue injection. We report a 70-year-old male who presented to the hospital after a road accident with a posttraumatic pseudoaneurysm that was treated by endovascular thrombin embolization. To the best of our knowledge, this is the first reported case of inferior gluteal artery false aneurysm treated by this method.
[en] To evaluate and describe the efficacy and side effects of a percutaneous thrombin injection under ultrasonography guidance for the treatment of iatrogenic pseudo aneurysms Eighteen consecutive iatrogenic pseudo aneurysm cases were treated with a thrombin injection. The thrombin was injected into the pseudo aneurysm cavity using a 22-gauge needle under ultrasonographic guidance. The causes of the pseudo aneurysms are as follows: post coronary angiography (9 cases), percutaneous coronary balloon angioplasty (5 cases), cerebral angiography (1 case), transhepatic chemo embolization (1 case), percutaneous trans femoral arterial stent insertion (1 case) and bone marrow aspiration for a marrow transplant (1 case). Only one case required a secondary thrombin injection due to recurrent flow in the pseudo aneurysm lumen, which was detected at the follow up Doppler ultrasound. Other seventeen cases were successfully treated on the first trial. There were no technical failures or complication related to the procedure. The average amount of thrombin injected was 733 IU. Nine out of 18 treated patients (50%) showed mild reactions to the thrombin including mild fever (4 cases), chilling sensation (3 cases), a chilling sensation with mild dyspnea (1 case), mild chest discomfort (1 case) after the thrombin injection. All these side effects were transient and improved several hours later. All the iatrogenic pseudo aneurysms were treated successfully with an ultrasound-guided percutaneous thrombin injection. There was a high rate of hypersensitivity to the bovine thrombin, which precaution should be taken to prevent more serious side effects
[en] This study presents the further establishment of impedimetric biosensors with aptamers as receptors. Aptamers are short single-stranded oligonucleotides which bind analytes with a specific region of their 3D structure. Electrical impedance spectroscopy is a sensitive method for analyzing changes on the electrode surface, e.g. caused by receptor-ligand-interactions. Fast and inexpensive prototyping of electrodes on the basis of commercially available compact discs having a 24 carat gold reflective layer was investigated. Electrode structures (CDtrodes ) in the range from few millimetres down to 100 microns were realized. The well-studied thrombin-binding aptamer (TBA) was used as receptor for characterizing these micro- and macro-electrodes. The impedance signal showed a linear correlation for concentrations of thrombin between 1.0 nM to 100 nM. This range corresponds well with most of the references and may be useful for the point-of-care testing (POCT).