AIM: To investigate the ability of Chinese cobra snake venom-metalloproteinase(MT) to induce the histamine release from human mast cells and its potential mechanisms.METHODS: MT was purified from the snake venom by using heparin agarose and Superdex75 chromatography.Mast cells were dispersed from human lung, colon and tonsil tissues after digestion with collagenase and hyaluronidase.The dispersed mast cells were then challenged with MT,stimulus and control in LP4 tubes for 15 min at 37 ℃.A glass fibre-based fluorometric assay was used to measure histamine in the supernatants of dispersed mast cells.RESULTS: MT induced a dose-dependent release of histamine from human colon,lung and tonsil mast cells.As low as 0.03(mg/L) of MT was able to stimulate significant histamine release from human colon mast cells,but a minimum of 0.3 or 30 mg/L of MT was required to stimulate a similar level of histamine release from lung or tonsil mast cells,respectively.The release of histamine from colon and lung mast cells in response to MT was maximized at 12 min following the addition of the stimulus.This was quite different from the picture of the peak histamine release from tonsil mast cells,in which histamine release was maximized at 8 min following the addition of MT.Pretreatment of cells with metabolic inhibitors and pertussis toxin reduced dramatically histamine release from human colon,lung and tonsil mast cells by MT.In exogenous Ca~(2+) and Mg~(2+) free experiments,the release of histamine induced by MT was significantly decreased.CONCLUSION: Cobra snake venom MT induces human mast cells to release histamine through a G-protein-related mechanism,which may contribute to the pathogenesis of venomous snake bite.

Objective To investigate the status quo of nutritional risks, malnutrition and nutritional support of inpatients with neoplasms and to provide a theoretical basis for making targeted clinic nutritional support standards and training programs.Methods Totally 421 patients with neoplasms who were admitted in Wuhan Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology between October 2015 and April 2016 were selected as respondents by cross-sectional survey and convenience sampling, and investigated with self-made nutritional support questionnaires based on Nutritional Risk Screening 2002 (NRS 2002) and China's real nursing practice.Results The incidence of malnutrition of the 421 patients was 44.2%, and the incidence of nutritional risks was 68.6%. The incidence of nutritional risks of patients with gastrointestinal neoplasms was higher than that of those patients with other neoplasms (χ2=24.541, 4.405;P<0.05); 92.6% of patients received nutritional support, 76.2% of which received parenteral nutrition and 14.5% received enteral nutrition; the incidence of gastrointestinal complications among those patients who received enteral nutrition was up to 30.2%, and the incidence of mechanical complications among those patients who received parenteral nutrition was up to 13.4%; the nursing achievement rates of the patients who received enteral nutrition and parenteral nutrition were 41.8% and 61.6%, respectively.Conclusions Inpatients with neoplasms show high incidence of nutritional risks and malnutrition. Therefore, healthcare workers should standardize the nutritional risk management for inpatients with neoplasms and strengthen the nutrition nursing training and quality control for nurses so as to reduce nutritional support-related complications among inpatients with neoplasms and accelerate their recovery.