Objective To investigate a method for isolation and purification of pancreatic islets in mice,aiming to enhance the quantity and activity of pancreatic islets.Methods The pancreas were digested by retrograde common bile duct perfusion of collagenase,discontinuous density gradient centrifugation and the islets were selected and purified by manual method.After overnight culture,the pancreatic islets were incubated by static glucose-stimulated insulin secretion (GSIS)and the islet function was assessed.The subcellular structure of islet βcells was observed under transmission electron microscopy.Results Using the modified method,(200 ±20)islets were collected in each mouse with a mean diameter of (175 ±22)μm. The insulin levels in the stimulation of low (2.8 mmol/L)and high glucose (16.7 mmol/L)were (0.33 ± 0.07)and (1.36 ±0.47 )ng/(islet · 60 min),which were detected by GSIS.Insulin levels in the stimulation of high sugar is 4.12 times of those of low sugar with a statistical significance (P <0.05).It was revealed by transmission electron microscopy that the pancreatic βcell membrane and mitochondrial membrane was intact and insulin granules of different sizes could be seen within βcells.Conclusions Retrograde common bile duct perfusion of collagenase,discontinuous density gradient centrifugation combined with manual selection in vitro is a convenient,fast and stable method for isolating mouse islets,which can get pancreatic islets with relatively high output,intact cellular morphology,and good reactivity of GSIS.

To investigate the renal venous and spermatic venous sampling in assisting the diagnosis of reninoma. The case of reninoma was retrospectively reviewed together with the literature review of reninoma diagnosed with renal venous and spermatic venous sampling. A young patient with hypertension and headache was admitted to our hospital. Laboratory test showed high plasma renin concentration (>500 mIU/L), and enhanced computed tomography(CT) in the upper abdomen showed a mass in left inferior renal pole. The concentration of renin in the left spermatic vein was significantly higher than that in renal veins and branches, and peripheral vein, which was considered the left reninoma possibility. The left renal mass was resected surgically and pathologic exam revealed reninoma. The renin level and the blood pressure recoveried normal after operation.The literature reported that the positive rate of renal vein segmental blood collection for locating renin tumor was only 8.3%-64%. The possible reason was that reninoma usually located in the renal cortex, and the tumor blood might be collected by renal capsule vein instead of renal vein. In fact, the renal capsule vein intersects with the lateral division of the spermatic vein, but there have been no reports about the localization of reninoma by spermatic vein sampling. Since renin secreted by reninoma may go into the spermatic vein through renal capsule vein, it should be noted that spermatic venous blood should be collected simultaneously in renal vein sampling when locating reninoma.