Acetylation of Rehmannia glutinosa polysaccharides and antioxidant activity of acetylated derivatives / 中国中药杂志

This study aims to acetylate Rehmannia glutinosa polysaccharides by acetic anhydride method, optimize process parameters and evaluate their antioxidant activity. With the degree of substitution(D_s) as a criterion, the effects of reaction time, acetic anhydride-to-polysaccharides ratio and temperature were investigated. Process parameters were optimized by single-factor experiment and response surface methodology. The infrared spectroscopy(IR) and scanning electron microscopy(SEM) proved the successful acetylation and were employed to preliminarily analyze the structural characteristics of acetylated derivatives. The results showed that the D_s was 0.327 under the optimal technological conditions, including m(acetic anhydride):m(R. glutinosa polysaccharides)=2.70, reaction time 3.0 h and temperature 48 ℃. Further, the antioxidant properties of acetylated derivatives were investigated in vitro and acetylation was found effective to improve the antioxidant activity of R. glutinosa polysaccharides. This study provides a reference for the further development and application of R. glutinosa polysaccharides.

Narrow-band imaging with magnification and the water immersion technique: a case-finding, cost-effective approach to diagnose villous atrophy

INTRODUCTION@#Narrow-band imaging with magnification endoscopy (NBI-ME) allows real-time visual assessment of the mucosal surface and vasculature of the gastrointestinal tract. This study aimed to determine the performance of NBI-ME combined with the water immersion technique (NBI-ME-WIT) in detecting villous atrophy.@*METHODS@#All patients who underwent gastroscopy were included. The duodenum was further examined with NBI-ME-WIT only after examination with white light endoscopy did not reveal a cause of anaemia or dyspepsia. Targeted biopsies were taken of visualised areas. NBI-ME-WIT findings were compared with the final histopathological analysis. We calculated the sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of NBI-ME-WIT in detecting villous atrophy and the hypothetical cost saved by using a biopsy-avoiding approach.@*RESULTS@#124 patients (83 female) with a mean age of 46 (range 18-82) years were included. The most common indication for gastroscopy was abdominal pain (39%), followed by anaemia (35%), chronic diarrhoea/altered bowel habits (19%) and dyspepsia (6%). NBI-ME-WIT was able to detect all nine patients with villous atrophy - eight patchy and one total villous atrophy. The Sn, Sp, PPV and NPV of NBI-ME-WIT in detecting villous atrophy were 100.0%, 99.1%, 90.0% and 100.0%, respectively. Taking into account the cost of biopsy forceps (AUD 17) and pathology (AUD 140), this biopsy-avoidance strategy could have saved AUD 18,055 in these patients.@*CONCLUSION@#NBI-ME-WIT is a specific and sensitive tool to recognise and accurately diagnose villous atrophy. Biopsies can be avoided in patients with normal-sized villi, which may decrease the overall cost of the procedure.

Multi-slice spiral CT (MSCT) : value of evaluating intestinal ischemia and therapeutic strategy for patients with intestinal obstruction / 中国医师杂志

Objective To explore early signs of strangulated bowel with multi-slice spiral CT (MSCT),and the ability of this diagnostic modality to indicate when surgical management is required for intestinal obstruction with ischemia.Methods A total of 746 patients of intestinal obstruction were investigated with MSCT scan.The final diagnosis was confirmed by surgery and/or angiography.According to the final diagnosis,those cases were divided into ischemia groups (n =70) and no ischemia group (n =676).According to surgical findings,the cases in ischemia group was divided into necrosis group (n =31) and no-necrosis group (n =39).The clinical manifestations,CT signs,and surgical/angiography findings were retrospectively evaluated in this study.Results Among the typical MSCT signs for evaluating intestinal ischemia of intestinal obstruction,no enhancement,thickening,and reduced unenhanced attenuation of bowel wall had relatively high sensitivity and specificity.However,intestinal expansion,pneumatosis and effusion was absence of high specificity,and gas in bowel wall or mesenteric vascular was absence of high sensitivity.Mesenteric congestion was another important sign for intestinal ischemia.Filling defect in mesenteric vascular was highly specific to diagnosis intestinal ischemia.The MSCT signs to assess intestinal necrosis in moderate-high risk intestinal obstruction included no enhancement of bowel wall (sensitivity 0.93,specificity 0.69),mesenteric congestion (sensitivity 0.97,specificity 0.64),filling defect in mesenteric vascular (sensitivity 0.78,specificity 0.92),and ascites (sensitivity 0.77,specificity 0.92).Conclusions MSCT is an important non-invasive examination in diagnosing intestinal blood perfusion disorder and intestinal necrosis.It is much more valuable to bowel obstruction assessment than the value of symptom and physical examinations of the patient.It can provide valuable guidance to treatment strategy of bowel obstruction patient.