These two authors contributed equally to this work. SUMMARYAgrobacterium genetically transforms plants by transferring and integrating T-(transferred) DNA into the host genome. This process requires both Agrobacterium and host proteins. VirE2 interacting protein 1 (VIP1), an Arabidopsis bZIP protein, has been suggested to mediate transformation through interaction with and targeting of VirE2 to nuclei. We examined the susceptibility of Arabidopsis vip1 mutant and VIP1 overexpressing plants to transformation by numerous Agrobacterium strains. In no instance could we detect altered transformation susceptibility. We also used confocal microscopy to examine the subcellular localization of Venus-tagged VirE2 or Venus-tagged VIP1, in the presence or absence of the other untagged protein, in different plant cell systems. We found that VIP1-Venus localized in both the cytoplasm and the nucleus of Arabidopsis roots, agroinfiltrated Nicotiana benthamiana leaves, Arabidopsis mesophyll protoplasts and tobacco BY-2 protoplasts, regardless of whether VirE2 was co-expressed. VirE2 localized exclusively to the cytoplasm of tobacco and Arabidopsis protoplasts, whether in the absence or presence of VIP1 overexpression. In transgenic Arabidopsis plants and agroinfiltrated N. benthamina leaves we could occasionally detect small aggregates of the Venus signal in nuclei, but these were likely to be imagining artifacts. The vast majority of VirE2 remained in the cytoplasm. We conclude that VIP1 is not important for Agrobacterium-mediated transformation or VirE2 subcellular localization.

Three-dimensional bioprinting is an emerging technology for fabricating living 3D constructs, and it has shown great promise in tissue engineering. Bioinks are scaffold materials mixed with cells used by 3D bioprinting to form a required cell-laden structure. In this paper, a novel bioink made of gelatin methacrylamide (GelMA) and collagen (Col) doped with tyrosinase (Ty) is presented for the 3D bioprinting of living skin tissues. Ty has the dual function of being an essential bioactive compound in the skin regeneration process and also as an enzyme to facilitate the crosslink of Col and GelMA. Further, enzyme crosslinking together with photocrosslinking can enhance the mechanical strength of the bioink. The experimental results show that the bioink is able to form stable 3D living constructs using the 3D bioprinting process. The cell culture shows that three major cell lines: human melanocytes (HEM), human keratinocytes (HaCat) and human dermal fibroblasts (HDF) exhibit high cell viabilities. The viability of these three cell lines is above 90%. The proliferation and scratching test show that Ty can enhance the proliferation of HEM, inhibit the growth and migration of HDF and not affect HaCat significantly. Animal tests show that the doped bioinks for 3D bioprinting can help form an epidermis and dermis, and thus have high potential as a skin bioink.

Bone tissue engineering is a powerful tool to treat bone defects caused by trauma, infection, tumors and other factors. Both silk fibroin (SF) and chitosan (CS) are non-toxic and have good biocompatibility, but are poor biological scaffolds when used alone. In this study, the microscopic structure and related properties of SF/CS composite scaffolds with different component ratios were examined. The scaffold material most suitable for osteoblast growth was determined, and these results offer an experimental basis for the future reconstruction of bone defects. First, via freeze-drying and chemical crosslinking methods, SF/CS composites with different component ratios were prepared and their structure was characterized. Changes in the internal structure of the SF and CS mixture were observed, confirming that the mutual modification between the two components was complete and stable. The internal structure of the composite material was porous and three-dimensional with a porosity above 90%. We next studied the pore size, swelling ratio, water absorption ratio, degradation and in vitro cell proliferation. For the 40% SF-60% CS group, the pore size of the scaffold was suitable for the growth of osteoblasts, and the rate of degradation was steady. This favors the early adhesion, growth and proliferation of MG-63 cells. In addition to good biocompatibility and satisfactory cell affinity, this material promotes the secretion of extracellular matrix materials by osteoblasts. Thus, 40% SF-60% CS is a good material for bone tissue engineering.

Aim: To investigate the relation between Helicobacter pylori associated gastroduodenal diseases and lymphoid tissue hyperplasia in the antral mucosa and to pursue its evolution after eradication of H pylori. Methods: Gastric antral biopsy specimens were obtained from 438 patients with H pylori positive gastroduodenal diseases (185 chronic gastritis, 69 gastric ulcer, and 184 duodenal ulcer) and 50 H pylori negative healthy controls. Lymphoid follicles and aggregates were counted and other pathological features were scored according to the updated Sydney system for classification of chronic gastritis. After a course of anti-H pylori treatment, biopsy specimens were obtained at four to six weeks, 12 months, and 24 months in the chronic gastritis patient group. Results: The total prevalence of lymphoid follicles and aggregates in the biopsies was 79.9% (350 of 438; 95% confidence intervals (CI), 0.76 to 0.84). The prevalence and density of lymphoid follicles and aggregates were significantly different in the various gastroduodenal diseases. The highest prevalence (89.9%; 95% CI, 0.83 to 0.97) and density (0.82) of lymphoid follicles and aggregates occurred in patients with gastric ulcers. The lowest prevalence of lymphoid follicles and aggregates was found in patients with chronic gastritis (74.6%; 95% CI, 0.68 to 0.81), and the lowest density of lymphoid follicles and aggregates (0.56) was seen in patients with duodenal ulcers. The prevalence and density of lymphoid follicles and aggregates correlated strongly with the activity and severity of gastric antral mucosal inflammation. The eradication of H pylori resulted in a decrease in the prevalence and density of lymphoid follicles and aggregates. Conclusion: The prevalence and density of lymphoid follicles and aggregates in gastric antral mucosal biopsies correlated closely with H pylori infection.

Objective: To evaluate the relationship between gastric cancer (GC) and precancerous lesions and bile reflux.Methods: Medical records of 30 465 participants who underwent gastroscopy between January and December 2018 in our center were reviewed. Their age, sex, time of endoscopy, endoscopic/histologic diagnosis and grade of bile reflux were recorded. The participants were further divided into the chronic gastritis group (n = 27 807), a precancerous lesion group (n = 1943) and a GC group (n = 715). The χ 2 tests and hierarchical analyses were performed.Results: Patients aged 18-27 years had a higher bile reflux rate than those aged 28-37 and 68-75 years (P < 0.001), while it did not differ between patients aged <50 years and those over 50 years (P = 0.639). It was lower in men than in women (P < 0.001). The bile reflux rate did not differ in terms of months, seasons and half of the year (all P > 0.05), but differed between morning and afternoon when they underwent the endoscopy (P = 0.000). There was an interrelationship between the severity of gastric mucosal disease and bile reflux grade (r = 0.171). After excluding the effects of sex, age and time of endoscopy on bile reflux, bile reflux rate in chronic gastritis and precancerous lesions was lower than in gastric cancer (P < 0.01).Conclusions: Bile reflux may be a risk factor for gastric cancer and precancerous lesions. A high grade of bile reflux may be associated with the progression of gastric mucosal diseases.bile reflux, gastric neoplasms, gastritis, intestinal metaplasia, precancerous lesions | INTRODUCTIONAs the fifth most common malignant tumor worldwide, more than one million new cases of gastric cancer (GC) were estimated to be diagnosed in 2018; while the cancer-related mortality rate of GC is the third highest (equivalent to one in every 12 deaths worldwide). 1 In China the incidence and mortality of GC are also high. 2 According to the Correa model, despite its complex etiology GC usually begins with atrophic gastritis, intestinal metaplasia or atypical hyperplasia, and progresses to carcinogenesis. 3 Helicobacter pylori (H. pylori) infection, patient's age, sex, * These authors contributed equally to this work.

An extrudable hydrogel with a tunable gelation time under physiological pH ranges based on the phase separation of gelatin and oxidized dextran was demonstrated. We envision that the easy handing properties of this hydrogel combined with thermosensitive physical gelation and postponed chemical reinforcing will provide a platform for 3D bioprinting applications.

OBJECTIVE:To investigate the cytotoxicity of silk fibroin/gelatin (SF/G) composite scaffolds in vitro as well as their biocompatibility and degradation in vivo. METHODS:The proliferation and relative growth rate of human hepatic QZG cells grown on different blends of two-dimensional (2-D) SF/G scaffolds were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry was used to evaluate apoptotic rate of QZG cells on different blends of 2-D SF/G scaffolds. The effect of silk protein materials on cell growth was observed by scanning electron microscopy. Threedimensional (3-D) SF/G scaffolds of three different ratios (diameter 10 mm, thickness 1 mm) were implanted into subcutaneous pockets on male Sprague-Dawley (SD) rats. On the 7th, 14th and 30th day post-implantation, the rats were sacrificed. The scaffold area including the surrounding tissues was retrieved. Hematoxylin and eosin staining was performed for observation under a light microscope. RESULTS:Significant cell attachment and proliferation on the SF/G scaffolds were observed. As the increased gelatin concentration, SF/G scaffolds became more amenable to cell adhesion. After the subcutaneous implantation of the SF/G scaffolds in SD rats, immunological rejection tests showed only slight inflammation, measured by the presence of inflamed cells on day 7 and 14. By day 30, each scaffold had been completely infiltrated and organized by fibroblasts and inflamed cells. The greater the gelatin concentration in the scaffold, the faster the degradation rate. CONCLUSION:Composite SF/G scaffolds are a promising candidate matrix for implantable bioartificial livers.

BackgroundEffective prevention against cancers depends heavily on sustained individual efforts practicing protective behaviors and avoiding risk factors in a complex sociocultural context, which requires continuous and personalized supports. Contemporary prevention relies primarily on strategies targeting general population with limited attention being paid to individualized approaches. This study tests a novel package called, in acronym of core intervention components, eCROPS-CA that leverages protective behaviors against over 80% leading cancers among high risk individuals via continuous and tailored counseling by village doctors.Methods/DesignThe study utilizes a quesi-RCT design involving 4320 high risk individuals selected, via rapid and detailed risk assessments, from about 72,000 farmers aged 35+ in 36 administrative villages randomized into equal intervention and delayed intervention arms. The intervention arm receives baseline and semiannual follow up evaluations plus eCROPS-CA for 5 years; while the control arm, only the baseline and follow-up evaluations for the first 5 years and eCROPS-CA starting from the 6th year if the intervention is proved effective. eCROPS-CA comprises electronic supports and supervision (e), counseling cancer prevention (C), recipe for objective behaviors (R), operational toolkit (O), performance-based incentives (P), and screening and assessment (S). Evaluation measures include: incidence and stage of the leading cancers, cancer-related knowledge, attitudes and practices; easy biophysical indicators (e.g., body mass index, blood pressure); intervention compliance, acceptance of the package.DiscussionThe prevention package incorporates key success factors in a synergetic way toward cost-effectiveness and long-term sustainability. It targets a set rather than any single cancer; choses village doctors as key solution to the widespread lack of professional manpower in implementing personalized and thus relatively sophisticated prevention; adopts real-time monitoring in reaching continuous improvement; utilizes smart web aids to enable prioritizing complex determinants of objective behaviors, linking counseling sessions happened at different time points and hence delivering highly coordinated prevention; uses 2-stage risk assessment models in identifying high risk individuals so as to focus on the most needed; applies standardized operation procedures in simplifying and smoothing behavior intervention yet ensuring delivery of essential steps and key elements.Trials registry ISRCTN33269053 Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1253-6) contains supplementary material, which is available to authorized users.