Mechanical intestinal obstruction due to isolated diffuse venous malformations in the gastrointestinal tract: A case report and review of literature

BACKGROUND Isolated gastrointestinal venous malformations(GIVMs)are extremely rare congenital developmental abnormalities of the venous vasculature.Because of their asymptomatic nature,the diagnosis is often quite challenging.However,as symptomatic GIVMs have nonspecific clinical manifestations,misdiagnosis is very common.Here,we report a case of isolated diffuse GIVMs inducing mechanical intestinal obstruction.A literature review was also conducted to summarize clinical features,diagnostic points,treatment selections and differential diagnosis in order that doctors may have a comprehensive understanding of this disease.CASE SUMMARY A 50-year-old man presented with recurrent painless gastrointestinal bleeding for two months and failure to pass flatus and defecate with nausea and vomiting for ten days.Digital rectal examination found bright red blood and soft nodular masses 3 cm above the anal verge.Computed tomography showed that part of the descending colon and rectosigmoid colon was thickened with phleboliths in the intestinal wall.Colonoscopy exhibited bluish and reddish multinodular submucosal masses and flat submucosal serpentine vessels.Endoscopic ultrasonography showed anechoic cystic spaces within intestinal wall.The lesions were initially thought to be isolated VMs involving part of the descending colon and rectosigmoid colon.Laparoscopic subtotal proctocolectomy,pullthrough transection and coloanal anastomosis and ileostomy were performed.Histopathology revealed intact mucosa and dilated,thin-walled blood vessels in the submucosa,muscularis,and serosa involving the entire colorectum.The patient recovered with complete symptomatic relief during the 52-mo follow-up period.CONCLUSION The diagnosis of isolated GIVMs is challenging.The information presented here is significant for the diagnosis and management of symptoms.

Functional and structural characterization of Norovirus GII.6 in recognizing histo-blood group antigens

Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is one of the predominant genotypes in humans,which recognizes the type ABO secretor of HBGAs.However,the structural basis of GII.6 NoV's interaction with HBGAs receptors remains elusive.In this study,we investigated the binding features of the GII.6 strain to HBGAs using saliva-and glycan-ELISA assays and characterized the molecular basis of the GII.6 virus that recognizes H disaccharide.We showed that the GII.6 P domain recognized some A and O secretor's saliva samples,most B secretor's saliva samples,and H disaccharide antigen,but did not bind non-secretors’saliva.Further,we determined the crystal structures of GII.6 and its complex with H disaccharides at 1.7Å,revealing that the P domain of GII.6 shares the conventional binding interface and mode of GII HBGAs.Single residue mutations at the GII.6-H binding sites could inhibit the binding of GII.6 to HBGAs,demonstrating that the interaction residues were crucial in maintaining NoV-glycan integrity.Finally,structural and sequence analyses showed that the major residues of the GII.6-H interaction were conserved among NoVs in the GII genogroup.Taken together,our study characterized the functional and structural features of GII.6 that allow it to interact with HBGAs,and shed light on NoV evolution,epidemiology,and anti-viral drug development.

Two-thiols-regulated fabrication of plasmonic nanoparticles with co-enhanced Raman scattering and circular dichroism responses

Plasmonicnanoparticles(PNPs)with stable nanogaps are important to achieve strong,uniform and quantitative gap-enhanced Raman scattering(GERS)signals.Chiral PNPs with plasmonic circular dichroism(PCD)responses have been discovered to be suitable for applications in enantiomeric recognition,cancer therapy and activation of immune system.Herein,two-thiolsmodulated growth was demonstrated to result in the acquisition of PNPs with synergistically enhanced GERS and PCD signals.4-Aminothiophenol(4-ATP)and cysteine(Cys)played the role of Raman reporter and chiral stimulus,respectively.At a fixed 4-ATP concentration,the GERS signal of PNPs was significantly enhanced with the increase of the concentration of Cys.Simultaneously,at a fixed concentration of Cys,an increase in PCD response was observed by elevating the concentration of 4-ATP.Both aforementioned molecules acted as morphology controllers,leading to the formation of helical shell.It is suggested that the giant GERS and PCD response were contributed by the‘‘hot spots''within the PNPs and more perfect helical shells.Our research pointed out a novel synthetic guideline to obtain PNPs with multiple functionalities by incorporating multi-ligands into the growth stages.