ISLET FORMATION AND REGENERATION

Objective To explore the mechanisms of differentiation and development of pancreatic endocrine cells as well as pancreatic regeneration.Methods Human embryonic pancreatic tissue at 7-14 weeks of gestation was collected.Diabetes mellitus rat model was induced with 65 mg/kg of streptozotocin.Insulin, glucagon, somatostatin, nestin, and cytokeratin 19 (CK19) of pancreatic tissues were observed by immunohistochemistry.Results At 9 weeks of gestation, pancreatic epithelial cells began to co-express insulin, glucagon, somatostatin, and CK19 before migration.Islet cells gradually congregated along with the increase of aging, and at 14 weeks of gestation histological examination showed islet formation.At 12 weeks of gestation, nestin-positive cells could be seen in the pancreatic mesenchyme.During early embryogenesis, islet cells of pancreatic ducts co-expressed insulin, glucagon, and somatostatin.During pancreatic regeneration after damage, nestin expression of islet cells increased.Conclusion In the early stage of embryogenesis, islet cells of primary pancreatic ducts can be differentiated to multipotential endocrine cells before migration.During tissue regeneration, pancreatic stem cells may differentiate and proliferate to form pancreatic islet.

Wnt/β-catenin signaling pathway is active in pancreatic development of rat embryo

瞄准：阐明在老鼠胚胎的胰腺的开发表明小径的 Wnt/beta-catenin 的角色。方法：beta-catenin 的 mRNAs， APC， cyclin D1 基因借助于半被放大从在不同时期和正常的胚胎的胰的量的反向的抄写聚合酶链反应(RT-PCR ) 老鼠的胰分别地。在 E14.5-E18.5 的胚胎的胰的这些基因的蛋白质表示被免疫检验组织化学的方法。结果：在 E14.5 的胚胎的胰， beta-catenin 和 cyclinD1 基因的抄本扩大被检测。在 E18.5 的胚胎的胰， beta-catenin 和 cyclinD1 基因的抄写层次变得比在另外的时期高得多。但是在成年老鼠胰， cyclinD1 基因的抄写不能被观察。仅仅直到 E18.5， APC 基因的 mRNA 的抄本扩大能被检测。令人惊讶地， APC 基因的抄写水平比在胚胎的胰在成年老鼠胰变得高得多。借助于免疫，组织化学的染色的、相同结果被 RP-PCR 获得到上面，除了在成年老鼠胰的 beta-catenin 蛋白质。结论：发信号的活跃 Wnt/beta-catenin 发生在老鼠胚胎的胰并且为胰腺的开发和机关形成可能是重要的。

On the Strong Approximation for a Simple Reentrant Line in Light Traffic Under First-buffer First-served Service Discipline

For a 2-station and 3-class reentrant line under first-buffer first-served(FBFS)service discipline in light traffic,we firstly construct the strong approximations for performance measures including the queue length,workload,busy time and idle time processes.Based on the obtained strong approximations,we use a strong approximation method to find all the law of the iterated logarithms(LILs)for the above four performance measures,which are expressed as some functions of system parameters:means and variances of interarrival and service times,and characterize the fluctuations around their fluid approximations.

Variability Analysis for a Two-station Queueing Network in Heavy Traffic with Arrival Processes Driven by Queues

The law of the iterated logarithm(LIL)for the performance measures of a two-station queueing network with arrivals modulated by independent queues is developed by a strong approximation method.For convenience,two arrival processes modulated by queues comprise the external system,all others are belong to the internal system.It is well known that the exogenous arrival has a great influence on the asymptotic variability of performance measures in queues.For the considered queueing network in heavy traffic,we get all the LILs for the queue length,workload,busy time,idle time and departure processes,and present them by some simple functions of the primitive data.The LILs tell us some interesting insights,such as,the LILs of busy and idle times are zero and they reflect a small variability around their fluid approximations,the LIL of departure has nothing to do with the arrival process,both of the two phenomena well explain the service station’s situation of being busy all the time.The external system shows us a distinguishing effect on the performance measures:an underloaded(overloaded,critically loaded)external system affects the internal system through its arrival(departure,arrival and departure together).In addition,we also get the strong approximation of the network as an auxiliary result.