Biochemical Characterization of a Recombinant UDP-glucosyltransferase from Rice and Enzymatic Production of Deoxynivalenol-3-O-β-d-glucoside

Glycosylation is an important plant defense mechanism and conjugates of Fusarium mycotoxins often co-occur with their parent compounds in cereal-based food and feed. In case of deoxynivalenol (DON), deoxynivalenol-3-O-β-d-glucoside (D3G) is the most important masked mycotoxin. The toxicological significance of D3G is not yet fully understood so that it is crucial to obtain this compound in pure and sufficient quantities for toxicological risk assessment and for use as an analytical standard. The aim of this study was the biochemical characterization of a DON-inactivating UDP-glucosyltransferase from rice (OsUGT79) and to investigate its suitability for preparative D3G synthesis. Apparent Michaelis constants (K_m) of recombinant OsUGT79 were 0.23 mM DON and 2.2 mM UDP-glucose. Substrate inhibition occurred at DON concentrations above 2 mM (K_i = 24 mM DON), and UDP strongly inhibited the enzyme. Cu²⁺ and Zn²⁺ (1 mM) inhibited the enzyme completely. Sucrose synthase AtSUS1 was employed to regenerate UDP-glucose during the glucosylation reaction. With this approach, optimal conversion rates can be obtained at limited concentrations of the costly co-factor UDP-glucose. D3G can now be synthesized in sufficient quantity and purity. Similar strategies may be of interest to produce β-glucosides of other toxins.     

Nation-Based Occurrence and Endogenous Biological Reduction of Mycotoxins in Medicinal Herbs and Spices

Medicinal herbs have been increasingly used for therapeutic purposes against a diverse range of human diseases worldwide. Moreover, the health benefits of spices have been extensively recognized in recent studies. However, inevitable contaminants, including mycotoxins, in medicinal herbs and spices can cause serious problems for humans in spite of their health benefits. Along with the different nation-based occurrences of mycotoxins, the ultimate exposure and toxicities can be diversely influenced by the endogenous food components in different commodities of the medicinal herbs and spices. The phytochemicals in these food stuffs can influence mold growth, mycotoxin production and biological action of the mycotoxins in exposed crops, as well as in animal and human bodies. The present review focuses on the occurrence of mycotoxins in medicinal herbs and spices and the biological interaction between mold, mycotoxin and herbal components. These networks will provide insights into the methods of mycotoxin reduction and toxicological risk assessment of mycotoxin-contaminated medicinal food components in the environment and biological organisms.     

Chronic Exposure to Deoxynivalenol Has No Influence on the Oral Bioavailability of Fumonisin B1 in Broiler Chickens

Both deoxynivalenol (DON) and fumonisin B₁ (FB₁) are common contaminants of feed. Fumonisins (FBs) in general have a very limited oral bioavailability in healthy animals. Previous studies have demonstrated that chronic exposure to DON impairs the intestinal barrier function and integrity, by affecting the intestinal surface area and function of the tight junctions. This might influence the oral bioavailability of FB₁, and possibly lead to altered toxicity of this mycotoxin. A toxicokinetic study was performed with two groups of 6 broiler chickens, which were all administered an oral bolus of 2.5 mg FBs/kg BW after three-week exposure to either uncontaminated feed (group 1) or feed contaminated with 3.12 mg DON/kg feed (group 2). No significant differences in toxicokinetic parameters of FB₁ could be demonstrated between the groups. Also, no increased or decreased body exposure to FB₁ was observed, since the relative oral bioavailability of FB₁ after chronic DON exposure was 92.2%.     

FibroScan行肝脏硬度检测和APRI评估慢性丙型肝炎患者肝纤维化程度价值比较*

目的 探讨使用FibroScan行肝脏硬度检测(LSM)和应用门冬氨酸氨基转移酶/血小板比值(APRI)评估慢性丙型肝炎(CHC)患者肝纤维化程度的价值。方法 2016年5月～2020年5月我院收治的CHC患者133例和同期健康体检者133名,接受FibroScan检查及血生化和血液检查,计算APRI。CHC患者接受肝穿刺活检。结果 CHC患者LSM和APRI分别为(10.3±4.2)和(0.8±0.3),显著高于健康人【分别为(4.3±2.0)和(0.3±0.1),P＜0.05】;52例S₁期患者LSM和APRI分别为(6.5±2.4)和(0.6±0.2),37例S₂期患者LSM和APRI分别为(10.3±2.9)和(0.9±0.3),28例S₃期患者LSM和APRI分别为(14.5±4.1)和(1.2±0.5),16例S₄期患者LSM和APRI分别为(18.4±5.7)和(1.8±0.6),相差显著(P＜0.05);经ROC分析LSM预测CHC患者显著肝纤维化(大于等于S2)的曲线下面积(AUC)为0.891,标准误为0.033,P=0.000,95%可信区间为0.826～0.956,最佳截断点为11.200,其诊断的敏感度为0.625,特异度为0.925,而APRI预测CHC患者显著肝纤维化的AUC为0.776,标准误为0.050,P=0.000,95%可信区间为0.678～0.875,最佳截断点为0.795,其敏感度为0.643,特异度为0.887;经相关性分析发现,LSM和APRI与CHC患者肝纤维化程度呈正相关(P＜0.05)。结论 应用LSM和APRI评估CHC患者肝纤维化程度有一定的临床价值,特别是对于存在显著肝纤维化的患者,可早期作出病情判断,对指导临床处理有很大的帮助,值得进一步研究。     

Post-liver transplant biliary complications: Current knowledge and therapeutic advances

Liver transplantation is the current standard of care for end-stage liver disease and an accepted therapeutic option for acute liver failure and primary liver tumors.Despite the remarkable advances in the surgical techniques and immunosuppressive therapy,the postoperative morbidity and mortality still remain high and the leading causes are biliary complications,which affect up to one quarter of recipients.The most common biliary complications are anastomotic and non-anastomotic biliary strictures,leaks,bile duct stones,sludge and casts.Despite the absence of a recommended treatment algorithm many options are available,such as surgery,percutaneous techniques and interventional endoscopy.In the last few years,endoscopic techniques have widely replaced the more aggressive percutaneous and surgical approaches.Endoscopic retrograde cholangiography is the preferred technique when duct-to-duct anastomosis has been performed.Recently,new devices and techniques have been developed and this has led to a remarkable increase in the success rate of minimally invasive procedures.Understanding the mechanisms of biliary complications helps in their early recognition which is the prerequisite for successful treatment.Aggressive endoscopic therapy is essential for the reduction of morbidity and mortality in these cases.This article focuses on the common post-transplant biliary complications and the available interventional treatment modalities.     

Design of a Unique Device for Residual Stresses Quantification by the Drilling Method Combining the PhotoStress and Digital Image Correlation

This paper presents a uniquely designed device combining the hole-drilling technique with two optical systems based on the PhotoStress and digital image correlation (DIC) method, where the digital image correlation system moves with the cutting tool. The authors aimed to verify whether the accuracy of the drilled hole according to ASTM E837-13a standard and the positioning accuracy of the device were sufficient to achieve accurate results. The experimental testing was performed on a thin specimen made from strain sensitive coating PS-1D, which allowed comparison of the results obtained by both methods. Although application of the PhotoStress method allows analysis of the strains at the edge of the cut hole, it requires a lot of experimenter’s practical skills to assess the results correctly. On the other hand, the DIC method allows digital processing of the measured data. However, the problem is not only to determine the data at the edge of the hole, the results also significantly depend on the smoothing levels used. The quantitative comparison of the results obtained was performed using finite element analysis.     

Change in the Recurrence Pattern and Predictors over Time after Complete Cure of Hepatocellular Carcinoma

Background/AimsWe investigated changes in recurrence rates and significant recurrence predictors over time after complete cure of hepatocellular carcinoma (HCC).MethodsA total of 1,491 patients with first-time diagnosis of Barcelona Clinic Liver Cancer stage A HCC, completely cured by treatment between 2007 and 2016, were recruited from two Korean tertiary institutes.ResultsThe mean age of the population (1,144 men and 347 women) was 58.6 years. Of the total population, 914 patients (61.3%) had liver cirrhosis. Nine-hundred and forty-one (63.1%) and 550 (36.9%) patients were treated with surgical resection and radiofrequency ablation (RFA), respectively. One-year cumulative incidences of HCC recurrence were 14.3%, 9.9%, and 5.1% from the time of treatment, 3 years after treatment, and 5 years after treatment, respectively. Upon multivariate analysis, multiple tumors, maximal tumor size ≥3 cm, and high Model for End-Stage Liver Disease scores were independently associated with increased HCC recurrence risk from the time of treatment and 1 and 2 years after curative treatment (all p<0.05, except for maximal tumor size ≥3 cm for recurrence 2 years after treatment). Meanwhile, liver cirrhosis and RFA were independently associated with the increased HCC recurrence risk for almost all time points (liver cirrhosis all p<0.05; RFA all p<0.005 except for recurrence from 5 years after treatment).ConclusionsThe recurrence rate of HCC after curative treatment gradually decreased over time. Two years after treatment, when tumor-related factors lose their prognostic implications, may be used as a cutoff to define the boundary between early and late recurrence of HCC. (Gut Liver 2021;15-429)     

Method for analyzing signaling networks in complex cellular systems

Now that the human genome has been sequenced, the challenge of assigning function to human genes has become acute. Existing approaches using microarrays or proteomics frequently generate very large volumes of data not directly related to biological function, making interpretation difficult. Here, we describe a technique for integrative systems biology in which: (i) primary cells are cultured under biologically meaningful conditions; (ii) a limited number of biologically meaningful readouts are measured; and (iii) the results obtained under several different conditions are combined for analysis. Studies of human endothelial cells overexpressing different signaling molecules under multiple inflammatory conditions show that this system can capture a remarkable range of functions by a relatively small number of simple measurements. In particular, measurement of seven different protein levels by ELISA under four different conditions is capable of reconstructing pathway associations of 25 different proteins representing four known signaling pathways, implicating additional participants in the NF-kappaBorRAS/mitogen-activated protein kinase pathways and defining additional interactions between these pathways.