Correlation between Helicobacter pylori-associated gastric diseases and colorectal neoplasia

AIM: To explore the correlation between Helicobacter pylori(H. pylori)-associated gastric diseases and colorectal neoplasia.METHODS: Patients included in this study underwent a colonoscopy and esophago-gastro-duodenoscopy(EGD) along with histopathological measurement between March 2012 and March 2015 at Qi-Lu Hospital of Shandong University, who also had results of H. pylori detection. A total of 233 cases were selected. Demographic data, H. pylori infection status(including results of rapid urease tests and gastric mucosa pathological examinations) and histopathological examination results of gastric and colorectal mucosa were gathered and analyzed. The statistical analysis focused on the prevalence of colorectal neoplasms among patients with various histopathological categories of the stomach. ORs and their 95%CI were calculated to describe the strengths of the associations.RESULTS: The incidence rates of colorectal adenoma without high-grade intraepithelial neoplasia(HGIEN)(OR = 2.400, 95%CI: 0.969-5.941), adenoma with HGIEN(5.333, 1.025-27.758) and adenocarcinoma(1.455, 0.382-5.543) were all higher for patients with H. pylori-associated gastritis than for those in the control group. The incidence rate of colorectal adenoma with HGIEN(3.218, 0.767-13.509) was higher in patients with intestinal metaplasia than in the control group, while the incidence rates of adenoma without HGIEN(0.874, 0.414-1.845) and adenocarcinoma(0.376, 0.096-1.470) were lower in the intestinal metaplasia group than in the control group. The incidence rate of colorectal adenoma without HGIEN(3.111, 1.248-7.753) was significantly higher in the gastric intraepithelial neoplasia group than in the control group, while the rates of adenoma with HGIEN(1.481, 0.138-15.941) and adenocarcinoma(2.020, 0.561-7.272) were higher in the gastric intraepithelial neoplasia group. Incidence rates of colorectal adenoma without HGIEN(1.067, 0.264-4.314), adenoma with HGIEN(2.667, 0.231-30.800) and adenocarcinoma(2.182, 0.450-10.585) were all higher in the gastric adenocarcinoma group than in the control group.CONCLUSION: H. pylori infection as well as H. pylori-associated gastric diseases are risk factors for colorectal neoplasia.

Research progress on chemopreventive effects of phytochemicals on colorectal cancer and their mechanisms

Colorectal cancer(CRC) is a type of cancer with high morbidity and mortality rates worldwide and has become a global health problem. The conventional radiotherapy and chemotherapy regimen for CRC not only has a low cure rate but also causes side effects. Many studies have shown that adequate intake of fruits and vegetables in the diet may have a protective effect on CRC occurrence, possibly due to the special biological protective effect of the phytochemicals in these foods. Numerous in vitro and in vivo studies have demonstrated that phytochemicals play strong antioxidant, anti-inflammatory and anti-cancer roles by regulating specific signaling pathways and molecular markers to inhibit the occurrence and development of CRC. This review summarizes the progress on CRC prevention using the phytochemicals sulforaphane, curcumin and resveratrol, and elaborates on the specific underlying mechanisms. Thus, we believe that phytochemicals might provide a novel therapeutic approach for CRC prevention, but future clinical studies are needed to confirm the specific preventive effect of phytochemicals on cancer.

Production of glycerol carbonate using crude glycerol from biodiesel production with DBU as a catalyst

The biodiesel production technology catalyzed by 1,8-diazabicycloundec-7-ene（DBU）is developed in this work.Crude glycerol containing DBU and DBU/glycerol/CO2（DGC）ionic compounds reacts directly with dimethyl carbonate（DMC）to produce high value-added glycerol carbonate（GC）catalyzed by DBU and DGC.The catalytic performance of DBU and DGC,as well as the kinetics of the reaction catalyzed by DBU,were investigated.The results show that DGC has a weak catalytic effect on the transesterification of glycerol and DMC.When the temperature is higher than 60℃,DGC catalyzes the reaction jointly with DBU,which is produced from the decomposition of DGC.DBU has a good catalytic effect on the reaction between glycerol and DMC,with 90%conversion of glycerol and 84%selectivity to GC under the following conditions：DMC-to-glycerol molar ratio of 3：1,4.0%DBU（based on glycerol mass）,reaction time of 60 min,and reaction temperature of 40℃.The apparent kinetics results show that the activation energies are 30.95 kJ·mol^-1 and 55.16 kJ·mol^-1 for the forward and reverse GC generation reactions,respectively,and the activation energy of the decomposition reaction of GC to glycidol（GD）is 26.58 kJ·mol^-1.

RNA m^(6)A reader YTHDF2 facilitates precursor miR-126 maturation to promote acute myeloid leukemia progression

As the most common internal modification of mRNA,Ne-methyladenosine(m^(6)A)and its regulators modulate gene expression and play critical roles in various biological and patholog-ical processes including tumorigenesis.It was reported previously that m^(6)A methyltransferase(writer),methyltransferase-like 3(METTL3)adds m^(6)A in primary microRNAs(pri-miRNAs)and fa-cilitates its processing into precursor miRNAs(pre-miRNAs).However,it is unknown whether m^(6)A modification also plays a role in the maturation process of pre-miRNAs and(if so)whether such a function contributes to tumorigenesis.Here,we found that YTHDF2 is aberrantly overexpressed in acute myeloid leukemia(AML)patients,especially in relapsed patients,and plays an onco-genic role in AML.Moreover,YTHDF2 promotes expression of miR-126-3p(also known as miR-126,as it is the main product of precursor miR-126(pre-miR-126)),a miRNA that was reported as an oncomiRNA in AML,through facilitating the processing of pre-miR-126 into mature miR-126.Mechanistically,YTHDF2 recognizes m^(6)A modification in pre-miR-126 and recruits AGO2,a regulator of pre-miRNA processing,to promote the maturation of pre-miR-126.YTHDF2 posi-tively and negatively correlates with miR-126 and miR-126's downstream target genes,respec-tively,in AML patients,and forced expression of miR-126 could largely rescue YTHDF2/Ythdf2 depletion-mediated suppression on AML cell growth/proliferation and leukemogenesis,indi-cating that miR-126 is a functionally important target of YTHDF2 in AML.Overall,our studies not only reveal a previously unappreciated YTHDF2/miR-126 axis in AML and highlight the ther-apeutic potential of targeting this axis for AML treatment,but also suggest that m^(6)A plays a role in pre-miRNA processing that contributes to tumorigenesis.

China’s urban expansion from 1990 to 2010 determined with satellite remote sensing

Based on the same data source of Landsat TM/ETM+ in 1990s,2000s and 2010s,all urban built-up areas in China are mapped mainly by human interpretation.Mapping results were checked and refined by the same analyst with the same set of criteria.The results show during the last 20 years urban areas in China have increased exponentially more than 2 times.The greatest area of urbanization changed from Northeastern provinces in 1990s to the Southeast coast of China in Jiangsu,Guangdong,Shandong,and Zhejiang in 2010s.Urban areas are mostly converted from croplands in China.Approximately 17750 km 2 croplands were converted into urban lands.Furthermore,the conversion from 2000 to 2010 doubled that from 1990 to 2000.During the 20 years,the most urbanized provinces are Jiangsu,Guangdong,Shandong and Zhejiang.We also analyzed built-up areas,gross domestic production (GDP) and population of 147 cities with a population of greater than 500000 in 2009.The result shows coastal cities and resource-based cities are with high economic efficiency per unit of built-up areas,resource-based cities have the highest population density,and the economic efficiency of most coastal provinces are lower than central provinces and Guangdong.The newly created urban expansion dataset is useful in many fields including trend analysis of urbanization in China;simulation of urban development dynamics;analysis of the relationship among urbanization,population growth and migration;studies of carbon emissions and climate change;adaptation of climate change;as well as land use and urban planning and management.

Geographical characteristics of China’s wetlands derived from remotely sensed data

In this paper, we report the first wetland mapping of the entire China using Landsat enhanced thematic mapper plus (ETM+) data. These data were obtained from the Global Land Cover Facility at the University of Maryland spanning from 1999 to 2002. A total of 597 scenes of Landsat images were georeferenced and mosaiced. Manual image interpretation of satellite images was aided with elevation data, soil data, land cover/land use data and Google Earth. The minimum mapping unit is 10 pixel × 10 pixel, equivalent to 9 ha. The aim of our first round of mapping was only targeted at the boundary delineation of any type of wetland except those wetlands that are under agricultural use (i.e., paddy fields), which has already been well mapped by others. Our interpretation results indicate that a total of 359478 km2 of wetlands are of non-agricultural use. Among our preliminarily mapped wetland, 339353 km2 are inland wetland, 2786 km2 are non-agricultural artificial wetland, and 17609 km2 are coastal wetland. Because low-tide is rarely captured in satellite images, an under-estimation of coastal wetland is inevitable. We conducted some statistics based on our mapped wetlands and compared them with those previously obtained from a number of sources including a land cover/land use map made with satellite images during the late 1990s and early 2000s, a marshland map developed in approximately the same period, survey data of coastal wetland in early 1980s, and area data for approximately 400 larger patches of marshland in China compiled in 1996. Because some inconsistencies exist in the guidelines of those different wetland surveys, difference in area is expected. Some further comparison indicates that the wetland distributions derived from the preliminary wetland map are reasonable and more objective than other sources. The mapping process also indicated that the method adopted by us was efficient and cost-effective. We also found that in order to ensure comparability of the wetland maps developed at different times, a set of standard guidelines on the wetland categories to be mapped, and the mapping methods to be used must be well conceived, developed and effectively employed. We carried out some initial geographical analysis on the distribution of wetlands.