The proinsulin C-peptide—a multirole model

The C-peptide links the insulin A and B chains in proinsulin, providing thereby a means to promote their efficient folding and assembly in the endoplasmic reticulum during insulin biosynthesis. It then facilitates the intracellular transport, sorting, and proteolytic processing of proinsulin into biologically active insulin in the maturing secretory granules of the β cells. These manifold functions impose significant constraints on the C-peptide structure that are conserved in evolution. After cleavage of proinsulin, the intact C-peptide is stored with insulin in the soluble phase of the secretory granules and is subsequently released in equimolar amounts with insulin, providing a useful independent indicator of insulin secretion. This brief review highlights many aspects of its roles in biosynthesis, as a prelude to consideration of its possible additional role(s) as a physiologically active peptide after its release with insulin into the circulation in vivo

Influence of CO(2) pneumoperitoneum on intracellular pH and signal transduction in cancer cells

Object: The authors studied the influence of CO(2) pneumoperitoneum on intracellular pH and signal transduction arising from cancer cell multiplication in laparoscopic tumor operation. Method: They set up a simulation of pneumoperitoneum under different CO(2) pressure, and then measured the variation of intracellular pH (pHi) at different time and the activity of protein kinase C (PKC) and protein phosphatase 2a (PP2a) at the end of the pneumoperitoneum. After 1 week, the concentration of cancer cells in the culture medium was calculated. Result: When the pressure of CO(2) pneumoperitoneum was 0, 10, 20, 30 mmHg respectively, the average pHi was 7.273, 7.075, 6.783, 6.693 at the end of the pneumoperitoneum; PKC activity was 159.4, 168.5, 178.0, 181.6 nmol/(g·min) and PP2a was 4158.3, 4066.9, 3984.0, 3878.5 nmol/(g·min) respectively. After 1 week, the cancer cells concentration was 2.15×10(5), 2.03×10(5), 2.20×10(5), 2.18×10(5) L(−1). Conclusion: CO(2) pneumoperitoneum could promote acidosis in cancer cells, inducing the activation of protein kinase C and deactivation of protein phosphatase 2a, but it could not accelerate the mitosis rate of the cancer cells

Saline conducted electric coagulation (SCEC): original experience in experimental hepatectomy

Objective: To evaluate the feasibility and superiority of a new coagulating and hemostatic method named “saline conducted electric coagulation (SCEC)”. Methods: The Peng's multifunction operative dissector (PMOD) was modified to enable saline to effuse persistently out of its nib at a constant speed. In a group of six New Zealand rabbits, two hepatic lobes of each rabbits were resected respectively by SCEC and conventional electric coagulation (EC). The features of SCEC were recorded by photo and compared with conventional EC. After 7 d, the coagulating depth was measured in each residual hepatic lobe. Hepatic tissue was dyed by hematoxylin and eosin (HE) and studied under a microscope. Results: The coagulating depth increased with the continuation of SCEC time. Hepatectomies were performed successfully, no rabbit died in the perioperative period. The incisal surface of SCEC was gray-white with no red bleeding point. There was a thick solidified layer at the margin and a thin red-white intermittent layer between the solidified layer and normal hepatic tissue at the vertical section of SCEC. The mean coagulating depth of SCEC was 1.8 cm vs. 0.3 cm of conventional EC. Pathological examination showed a mild inflammatory reaction by SCEC. Conclusions: SCEC is a feasible and safe method for surgical hemostasis. As a new technique for liver resection, SCEC shows better coagulating effect and milder inflammatory reaction than conventional EC. Our study shows bloodless liver resection can also be performed by SCEC, especially for liver malignant tumor

Transumbilical single-port laparoscopic cholecystectomy using traditional laparoscopic instruments: a report of thirty-six cases

Objective: To evaluate the feasibility and safety of the operation of transumbilical single-port laparoscopic cholecystectomy (TSPLC) by traditional laparoscopic instruments and summarize the initial experience. Methods: Sixty subjects with cholelithiasis were divided into two groups. One group (36 cases) underwent TSPLC and the control group (24 cases) underwent traditional three-port laparoscopic cholecystectomy (LC). Postoperative complications were observed and operation time, hospital days, visual analogue scale (VAS) after 6 and 24 h of operation, and subject satisfaction score were measured. Results: TSPLC and traditional LC were performed successfully in the two groups. The operation time in the TSPLC group was significantly longer than that in the control group. There was no statistically significant difference in hospital stay and VAS between the TSPLC and control groups. The subject satisfaction score in the TSPLC group was 91.2, significantly higher than that in the control group (P<0.01). All subjects recovered from the operation and no postoperative complication occurred during the period of two weeks after operation. Conclusions: TSPLC is a feasible and safe method for cholecystectomy, although it may be more time-consuming. However, it is welcomed by patients who are more concerned with cosmetic outcomes. Future studies are needed to confirm its disadvantages and contraindications

Increasing the immune activity of exosomes: the effect of miRNA-depleted exosome proteins on activating dendritic cell/cytokine-induced killer cells against pancreatic cancer

Background: Tumor-derived exosomes were considered to be potential candidates for tumor vaccines because they are abundant in immune-regulating proteins, whereas tumor exosomal miRNAs may induce immune tolerance, thereby having an opposite immune function. Objective: This study was designed to separate exosomal protein and depleted exosomal microRNAs (miRNAs), increasing the immune activity of exosomes for activating dendritic cell/cytokine-induced killer cells (DC/CIKs) against pancreatic cancer (PC). Methods: PC-derived exosomes (PEs) were extracted from cultured PANC-1 cell supernatants and then ruptured; this was followed by ultrafiltered exosome lysates (UELs). DCs were stimulated with lipopolysaccharide (LPS), PE, and UEL, followed by co-culture with CIKs. The anti-tumor effects of DC/CIKs against PC were evaluated by proliferation and killing rates, tumor necrosis factor-α (TNF-α) and perforin secretion. Exosomal miRNAs were depleted after lysis and ultrafiltration, while 128 proteins were retained, including several immune-activating proteins. Results: UEL-stimulated DC/CIKs showed a higher killing rate than LPS- and PE-stimulated DC/CIKs. Conclusions: miRNA-depleted exosome proteins may be promising agonists for specifically activating DC/CIKs against PC

Embryonic Cell Lines with Endothelial Potential: An in Vitro System for Studying Endothelial Differentiation

10.1161/01.ATV.0000120375.51196.73Arteriosclerosis, Thrombosis, and Vascular Biology244691-696ATVB