Solitary rectal ulcer syndrome:Clinical features,pathophysiology,diagnosis and treatment strategies

Solitary rectal ulcer syndrome(SRUS)is an uncommon benign disease,characterized by a combination of symptoms,clinical findings and histological abnormalities.Ulcers are only found in 40%of the patients;20%of the patients have a solitary ulcer,and the rest of the lesions vary in shape and size,from hyperemic mucosa to broad-based polypoid.Men and women are affected equally,with a small predominance in women.SRUS has also been described in children and in the geriatric population.Clinical features include rectal bleeding,copious mucus discharge,prolonged excessive straining,perineal and abdominal pain,feeling of incomplete defecation,constipation,and rarely,rectal prolapse.This disease has well-described histopathological features such as obliteration of the lamina propria by fibrosis and smooth muscle fibers extending from a thickened muscularis mucosa to the lumen.Diffuse collage deposition in the lamina propria and abnormal smooth muscle fiber extensions are sensitive markers for differentiating SRUS from other conditions.However,the etiology remains obscure,and the condition is frequently associated with pelvic floor disorders.SRUS is difficult to treat,and various treatment strategies have been advocated,ranging from conservative management to a variety of surgical procedures.The aim of the present review is to summarize the clinical features,pathophysiology,diagnostic methods and treatment strategies associated with SRUS.

Effect of a high-fat diet in development of colonic adenoma in an animal model

AIM: To investigate the effect of a high-fat diet in the formation of the precursors of colorectal cancer using an animal model.METHODS: Wistar rats were divided into two groups that were fed either a high-fat diet(HFD) or a normalfat diet(ND), and 1,2-dimethylhydrazine was administered at a dose of 40 mg/kg for 10 wk. The body weight/liver weight/epididymal fat weight were recorded after rats were sacrificed, and the formation of colonic adenoma was also observed. The levels of insulin, leptin, tumor necrosis factor(TNF)-α, insulinlike growth factor(IGF)-1 and triglycerides were determined by enzyme-linked immunosorbent assay in order to compare the altered levels of biochemical indices and inflammatory cytokines in the serum between rats fed an ND and HFD. Cell proliferation activity(Ki-67) was determined by immunohistochemical analysis. Western blot and immunofluorescence staining were used to examine the expression of pro-liferating cell nuclear antigen(PCNA), cyclooxygenase(COX)-2, cyclin D1, β-catenin and nuclear factor(NF)-κB proteins in the adenoma and comparative control tissues.RESULTS: The number of colonic adenomas and the colonic epithelial Ki-67 were significantly higher in the HFD group than in the ND group. The HFD group also had increased body weight, liver weight and epididymal fat weight, which were associated with increased levels of serum insulin, leptin, TNF-α, IGF-1 and triglycerides. HFD induced upregulation of PCNA, COX-2, cyclin D1, β-catenin and NF-κB proteins, as revealed by Western blot and immunofluorescence staining.CONCLUSION: HFD promotes the formation of colonic adenoma through inflammation, metabolic abnormalities, and increases cell cycle progression.

Alternative splicing of VEGFA,APP and NUMB genes in colorectal cancer

AIM:To investigate alternative splicing in vascular endothelial growth factor A(VEGFA),amyloid beta precursor protein(APP),and Numb homolog(NUMB) in colorectal cancer(CRC).METHODS:Real-time quantitative reverse transcriptase polymerase chain reaction(q RT-PCR) and PCRrestriction fragment length polymorphism analyses were performed to detect the expression of VEGFA,APP,and NUMB mR NA in 20 CRC tissues and matched adjacent normal tissues,as well as their alternative splicing variants.RESULTS:q RT-PCR analysis revealed that the expression of APP,NUMB,and VEGFA 165 b m RNA were significantly downregulated,while VEGFA m RNA was upregulated,in CRC tissues(all P < 0.05).PCRrestriction fragment length polymorphism analysis revealed that the expression of VEGFA 165a/b in CRC tissues was significantly higher than in adjacent normal tissues(P < 0.05).Compared with adjacent normal tissues,the expression of NUMB-PRRS in CRC tissues was significantly decreased(P < 0.05),and the expression of NUMB-PRRL was increased(P < 0.05).CONCLUSION:Alternative splicing of VEGFA,APP,and NUMB may regulate the development of CRC,and represent new targets for its diagnosis,prognosis,and treatment.

An efficient and coordinated mapping algorithm in virtualized SDN networks

Software-defined networking(SDN) enables the network virtualization through SDN hypervisors to share the underlying physical SDN network among multiple logically isolated virtual SDN networks(v SDNs),each with its own controller.The v SDN embedding,which refers to mapping a number of v SDNs to the same substrate SDN network,is a key problem in the SDN virtualization environment.However,due to the distinctions of the SDN,such as the logically centralized controller and different virtualization technologies,most of the existing embedding algorithms cannot be applied directly to SDN virtualization.In this paper,we consider controller placement and virtual network embedding as a joint vS DN embedding problem,and formulate it into an integer linear programming with objectives of minimizing the embedding cost and the controller-to-switch delay for each v SDN.Moreover,we propose a novel online vS DN embedding algorithm called CO-v SDNE,which consists of a node mapping stage and a link mapping stage.In the node mapping stage,CO-vS DNE maps the controller and the virtual nodes to the substrate nodes on the basis of the controller-to-switch delay and takes into account the subsequent link mapping at the same time.In the link mapping stage,CO-v SDNE adopts the k-shortest path algorithm to map the virtual links.The evaluation results with simulation and Mininet emulation show that the proposed CO-v SDNE not only significantly increases the long-term revenue to the cost ratio and acceptance ratio while guaranteeing low average and maximum controller-to-switch delay,but also achieves good v SDN performance in terms of end-to-end delay and throughput.