OBJECTIVE To observe the effect of natrin from Naja naja atra(Chinese cobra)on intracellular free calcium overload,and to discuss the protective effect and the possible mechanism of natrin on myocardium calcium(Ca2+)and potassium(K+)ion channels in the primary cardiomyocytes of SD neonatal rats. METHODS The primary cardiomyocytes of SD neonatal rats were used,which were respectively pretreated with natrin 5,25 and 125 mg · L-1 for 24 h before injury was induced by H2O2 0.3 mmol · L- 1. The dynamic variation of intracellular calcium was monitored by laser confocal microscopy using Fluo-3 as Ca2+fluorescence probe. Additionally,the cardio myocytes of neonatal rats were pretreated for 24 h using different concentrations of natrin 5,25,125 mg · L-1 and verapamil 5 nmol · L-1,followed by exposure to H2O2 0.3 mmol · L-1 for 15 min. Then,the mRNA expressions of calcium channels subunits Cav1.2,Calm,RyR2 and potassium channel Kir6.2 were analyzed by FQ-PCR method. RESULTS Laser confocal microscopy revealed that H2O2 obviously caused calcium overload in cardiomyocytes, giving rise to 49.37% fluorescence increase in intracellular calcium compared with the control group(P<0.01). However,natrin 5,25 and 125 mg·L-1 resulted in 27.52%, 12.71% and 5.15% fluorescence increase in intracellular calcium,respectively,compared with the control group(P<0.01). Moreover, the PCR results showed that the mRNA expressions of Cav1.2, Calm and RyR2 in the myocardial cells treated with H2O2 were increased 2.78,2.26,and 5.34 times as compared with the control group,while Kir6.2 displayed a 1.79-fold expression level(P<0.01). By contrast, the combination of natrin and verapamil significantly decreased the mRNA expression of Cav1.2,Calm and RyR2,compared to the H2O2-treated group(P<0.01). Meanwhile,the expression of Kir6.2 was considerably higher than that of the H2O2-treated group(P<0.05). CONCLUSION Natrin can reduce the intracellular calcium overload of cardiomyocytes induced by H2O2 and shows a protective effect against oxidative damage for cardiomyocytes. The possible mechanism is that natrin can decrease the mRNA expression of Cav1.2,Calm,RyR2 and increase the expression of Kir6.2 of the H2O2-induced cardiomyocytes.

Objective To investigate the imaging characteristics of nontraumatic spontaneous intramural hematoma of small bowel secondary to warfarin therapy.Methods The retrospective and descriptive study was conducted.The clinical data of 12 patients with nontraumatic spontaneous intramural hematoma of small bowel secondary to warfarin therapy who were admitted to the First People's Hospital of Wenling (11 patients) and Taizhou Hospital of Zhejiang Province (1 patient) between January 2010 and December 2016 were collected.Patients received plain and enhanced scans of computed tomography (CT).Patients stopped warfarin therapy,received intramuscular injection of vitamin K1 and fresh-frozen plasma transfusion.Observation indicators:(1) primary signs of CT:① small bowel wall thickening;② increased density of small bowel wall;(2) secondary signs of CT:intestine lumen stenosis,intestinal pneumatosis,perienteric changes and other concomitant signs;(3) treatment situations.Measurement data with normal distribution were represented as (x)±s.Measurement data with skewed distribution were described as M (range).Results Twelve patients received total abdomen plain scans of CT,and 7 received total abdomen enhanced scans of CT.(1) Primary signs of CT:① Small bowel wall thickening.CT of 12 patients showed solitary,homogeneously symmetric,consecutive and diffuse thickening of small bowel wall,including ileal involvement in 7 patients and jejunum involvement in 5 patients.Ascending part of duodenum of 3 patients involved the 2nd and 3rd groups small bowel.The average length of involved small bowel was 30.7 cm (range,11.0-58.0 cm).There was no multifocal thickening or colonic involvement.Of 12 patients,10 and 2 showed moderate thickening (thickness was 1.0-2.0 cm) and severe thickening (thickness ＞ 2.0 cm),and the thickest small bowel wall was 2.5 cm.② Increased density of small bowel wall.Twelve patients showed varying degrees of increased density of small bowel wall,with an average value of 49.7 HU (range,36.0-63.4 HU).Of 12 patients,homogeneously increased whole layer density of small bowel wall were detected in 4 patients,higher submucous layer density of small bowel compared with serosal layer density in 4 patients,and all of the above characteristics in 4 patients.Enhanced scans of CT in 7 patients showed enhancement in small bowel mucosal layer and serosal layer,no obvious enhancement in the submucous layer of small bowel wall,clear layers,and a target sign when small bowel lumen was perpendicular to scan slice,including 5 patients with obvious enhancement in small bowel mucosal layer,spring-like change,and clear imaging in portal vein phase.(2) Secondary signs of CT:① Intestine lumen stenosis:12 patients had varying degrees of intestine lumen stenosis.Five patients were complicated with small bowel obstruction,showing a gas-liquid level.② Intestinal pneumatosis:2 of 12 patients showed patchy and mottled gas shadow.③ Perienteric changes and other concomitant signs:12 patients showed obviously increased fat density in surrounding area of involved small bowel and corresponding mesenteric area,and indistinct outside small bowel,including 8 with lots of lath-like high density shadow in surrounding area of small bowel and mesenteric area.The varying degrees of hemoperitoneum were seen in 12 patients.(3) Treatment situations:of 12 patients,9 underwent correct treatments,8 of them were improved,and 1 of them with persistently severe abdominal pain underwent urgent explorative laparotomy,showing hemorrhage and necrosis,and then underwent surgery;3 didn't undergo correct treatment,without improved or severe symptoms.Conclusion Patients undergoing anticoagulant therapy show acute abdominal pain with abnormal coagulation function,small bowel wall thickening and increased density by CT scans,hemoperitoneum complicated with intestine lumen stenosis,small bowel obstruction and hematocele in surrounding area of small bowel and mesenteric area,these are highly indicative of nontraumatic spontaneous intramural hematoma of small bowel secondary to warfarin therapy.