Tween-80 and impurity induce anaphylactoid reaction in zebrafish.

A number of recent reports suspected that Tween-80 in injectable medicines, including traditional Chinese medicine injections could cause life-threatening anaphylactoid reaction, but no sound conclusion was drawn. A drug-induced anaphylactoid reaction is hard to be assayed in vitro and in conventional animal models. In this study, we developed a microplate-based quantitative in vivo zebrafish assay for assessing anaphylactoid reaction and live whole zebrafish mast cell tryptase activity was quantitatively measured at a wavelength of 405 nm using N-benzoyl-dl-arginine p-nitroanilide as a substrate. We assessed 10 batches of Tween-80 solutions from various national and international suppliers and three Tween-80 impurities (ethylene glycol, 2-chloroethanol and hydrogen peroxide) in this model and found that three batches of Tween-80 (nos 2, 20080709 and 20080616) and one Tween-80 impurity, hydrogen peroxide (H2 O2 ), induced anaphylactoid reactions in zebrafish. Furthermore, we found that H2 O2 residue and peroxide value were much higher in Tween-80 samples 2, 20080709 and 20080616. These findings suggest that H2 O2 residue in combination with oxidized fatty acid residues (measured as peroxide value) or more likely the oxidized fatty acid residues in Tween-80 samples, but not Tween-80 itself, may induce anaphylactoid reaction. High-throughput zebrafish tryptase assay developed in this report could be used for assessing safety of Tween-80-containing injectable medicines and potentially for screening novel mast cell-modulating drugs.

Human cardiotoxic drugs delivered by soaking and microinjection induce cardiovascular toxicity in zebrafish.

Cardiovascular toxicity is a major challenge for the pharmaceutical industry and predictive screening models to identify and eliminate pharmaceuticals with the potential to cause cardiovascular toxicity in humans are urgently needed. In this study, taking advantage of the transparency of larval zebrafish, Danio rerio, we assessed cardiovascular toxicity of seven known human cardiotoxic drugs (aspirin, clomipramine hydrochloride, cyclophosphamide, nimodipine, quinidine, terfenadine and verapamil hydrochloride) and two non-cardiovascular toxicity drugs (gentamicin sulphate and tetracycline hydrochloride) in zebrafish using six specific phenotypic endpoints: heart rate, heart rhythm, pericardial edema, circulation, hemorrhage and thrombosis. All the tested drugs were delivered into zebrafish by direct soaking and yolk sac microinjection, respectively, and cardiovascular toxicity was quantitatively or qualitatively assessed at 4 and 24 h post drug treatment. The results showed that aspirin accelerated the zebrafish heart rate (tachycardia), whereas clomipramine hydrochloride, cyclophosphamide, nimodipine, quinidine, terfenadine and verapamil hydrochloride induced bradycardia. Quinidine and terfenadine also caused atrioventricular (AV) block. Nimodipine treatment resulted in atrial arrest with much slower but regular ventricular heart beating. All the tested human cardiotoxic drugs also induced pericardial edema and circulatory disturbance in zebrafish. There was no sign of cardiovascular toxicity in zebrafish treated with non-cardiotoxic drugs gentamicin sulphate and tetracycline hydrochloride. The overall prediction success rate for cardiotoxic drugs and non-cardiotoxic drugs in zebrafish were 100% (9/9) as compared with human results, suggesting that zebrafish is an excellent animal model for rapid in vivo cardiovascular toxicity screening. The procedures we developed in this report for assessing cardiovascular toxicity in zebrafish were suitable for drugs delivered by either soaking or microinjection.

Early diagnosis and treatment of acute or subacute spinal epidural hematoma.

BACKGROUND: Despite low morbidity, acute or subacute spinal epidural hematoma may develop quickly with a high tendency to paralysis. The delay of diagnosis and therapy often leads to serious consequences. In this study we evaluated the effects of a series of methods for the diagnosis and treatment of the hematoma in 11 patients seen in our hospital. METHODS: Of the 11 patients (8 males and 3 females), 2 had the hematoma involving cervical segments, 2 cervico-thoracic, 4 thoracic, 1 thoraco-lumbar, and 2 lumbar. Three patients had quadriplegia, including one with central cord syndrome; another had Brown-Sequard's syndrome; and the other seven had paraplegia. Five patients were diagnosed at our hospitals within 3 - 48 hours after appearance of symptoms, and 6 patients were transferred from community hospitals within 21 - 106 hours after development of symptoms. Key dermal points, key muscles and the rectal sphincter were determined according to the American Spinal Injury Society Impairment Scales as scale A in two patients, B in 5 and C in 4. Emergency MRI in each patient confirmed that the dura mater was compressed in the spinal canal, with equal intensity or hyperintensity on T(1) weighted image and mixed hyperintensity on T(2) weighted image. Preventive and curative measures were taken preoperatively and emergency operation was performed in all patients. Open laminoplasty was done at the cervical and cervico-thoracic segments, laminectomy at the thoracic segments, laminectomy with pedicle screw fixation at the thoraco-lumbar and lumbar segments involving multiple levels, and double-sided laminectomy with the integrity of articular processes at the lumbar segments involving only a single level. During the operation, special attention was given to hematoma evacuation, hemostasis and drainage tube placement. RESULTS: Neither uncontrollable hemorrhage nor postoperative complications occurred. All patients were followed up for 1 - 6 years. A marked difference was noted between postoperative and preoperative scales (u = 3.66, P < 0.01). Most patients recovered after therapy, but the recovery of patients treated at our hospitals was superior to that of those transferred from community hospitals (t = 2.95, P < 0.05). Of the patients treated at our hospitals, 4 were cured and 1 was upgraded with scale from A to D, whereas none of those transferred from community hospitals recovered completely, even one remained scale C. CONCLUSIONS: Physical examination plus MRI is essential to early diagnosis of acute or subacute spinal epidural hematoma. Preventive and curative measures including emergency operation are helpful to the recovery of patients' nerve function.

Current status and perspective of diagnosis and treatment of thoracolumbar fracture in China.

Since the late 20th century owing to the improvement of spinal surgery techniques, the diagnosis and treatment of thoracolumbar fracture have been perfected more and more. Although the advent of modern spinal surgery in China was late, we have gained some advanced achievements owing to various international communications benefited from the open policy. Therefore, it is essential to evaluate the current status and perspective of diagnosis and treatment of thoracolumbar fracture. There are several issues we would like to discuss here.