Improvement and Optimization of Standards for a Preclinical Animal Test Model of Laser Induced Choroidal Neovascularization

Background

As the murine model of laser-induced choroidal neovascularization (CNV) is becoming the most established and commonly utilized model worldwide for studying the pathogenesis of CNV and its response to treatment, specific operating standards are yet to be clarified. The purpose of this study is to compare the lesion size of CNV in mice with different ages, sex, durations of CNV process, and treated positions of laser spots, to make recommendations that may improve and optimize the quality of the model.

Methods and Results

C57/BL6 mice of different ages were treated with diode laser photocoagulation per eye and perfused with PBS containing fluorescein-labeled dextran at different time of observation. Choroid flat mounts, were then examined by fluorescence microscopy for the measurement of CNV area. Messenger-RNA expression levels of several angiogenic cytokines in eye cups of male and female C57BL/6 mice at 5–8 and 16–20 week-old were analyzed by real-time RT-PCR assay. The results showed significantly more CNV area in eyes of female mice compared to male mice with the expression level of several angiogenic cytokines elevated. 16–20-week-old female mice developed the biggest area of CNV. The mean area of CNV increased significantly at the 14^th day after photocoagulation. Laser spots delivered 1PD away from the optic disc induced the biggest area of CNV compared to those 2PD or 3PD away. Interaction of NV was observed in laser spots delivered less than 1PD away from each other.

Conclusion

The current results suggest that 16–20-week-old female C57BL/6 mice developed the most distinct CNV lesion size with laser spots delivered 1PD away from the optic disc. The best time to observe and analyze is the 14^th day after photocoagulation.     

A Modified Delta-Shaped Gastroduodenostomy in Totally Laparoscopic Distal Gastrectomy for Gastric Cancer: A Safe and Feasible Technique

Background

The present study introduced a modified delta-shaped gastroduodenostomy (DSG) technique and assessed the safety, feasibility and clinical results of this procedure in patients undergoing totally laparoscopic distal gastrectomy (TLDG) for gastric cancer (GC).

Materials and Methods

A total of 102 patients with distal GC undergoing TLDG with modified DSG between January 2013 and December 2013 were enrolled. A retrospective study was performed using a prospectively maintained comprehensive database to evaluate the results of the procedure. Univariate and multivariate analyses were performed to estimate the predictive factors for postoperative morbidity.

Results

The mean operation time was 150.6±30.2 min, the mean anastomosis time was 12.2±4.2 min, the mean blood loss was 48.2±33.2 ml, and the mean times to first flatus, fluid diet, soft diet and postoperative hospital stay were 3.8±1.3 days, 5.0±1.0 days, 7.4±2.1 days and 12.0±6.5 days, respectively. Two patients with minor anastomotic leakage after surgery were managed conservatively; no patient experienced any complications around the anastomosis, such as anastomotic stricture or anastomotic hemorrhage. Univariate analysis showed that age, gastric cancer with hemorrhage and cardiovascular disease combined were significant factors that affected postoperative morbidity (P<0.05). Multivariate analysis found that gastric cancer with hemorrhage was the independent risk factor for the postoperative morbidity (P = 0.042). At a median follow-up of 7 months, no patients had died or experienced recurrent or metastatic disease.

Conclusions

The modified DSG was technically safe and feasible, with acceptable surgical outcomes, in patients undergoing TLDG for GC, and this procedure may be promising in these patients.     

Activation of Notch-1 enhances epithelial-mesenchymal transition in gefitinib-acquired resistant lung cancer cells

Despite an initial response to EGFR tyrosine kinase inhibitors (EGFR-TKI) in EGFR mutant lung cancer, most patients eventually become resistant and result in treatment failure. Recent studies have shown that epithelial to mesenchymal transition (EMT) is associated with drug resistance and cancer cell metastasis. Strong multiple gene signature data indicate that EMT acts as a determinant of insensitivity to EGFR-TKI. However, the exact mechanism for the acquisition of the EMT phenotype in EGFR-TKI resistant lung cancer cells remains unclear. In the present study, we showed that the expression of Notch-1 was highly upregulated in gefitinib-resistant PC9/AB2 lung cancer cells. Notch-1 receptor intracellular domain (N1IC), the activated form of the Notch-1 receptor, promoted the EMT phenotype in PC9 cells. Silencing of Notch-1 using siRNA reversed the EMT phenotype and restored sensitivity to gefitinib in PC9/AB2 cells. Moreover, Notch-1 reduction was also involved in inhibition of anoikis as well as colony-formation activity of PC9/AB2 cells. Taken together, these results provide strong molecular evidence that gefitinib-acquired resistance in lung cancer cells undergoing EMT occurs through activation of Notch-1 signaling. Thus, inhibition of Notch-1 can be a novel strategy for the reversal of the EMT phenotype thereby potentially increasing therapeutic drug sensitivity to lung cancer cells.     

酵母菌相关实验的一些改进

高中生物学教学中,与酵母菌相关的实验有多个,如“探究酵母菌的呼吸方式”、“酵母菌的酒精发酵”等。下面就针对这些实验的可操作性,对实验装置进行一些改进,以利于探究实验的顺利进行。     

Resistance-related physiological response of rice leaves to the compound stress of enhanced UV-B radiation and Magnaporthe oryzae

An enhanced UV-B radiation (5.0?kJ?m^?2) was supplied before, during, and after Magnaporthe oryzae infection. The effects of single and compound stress of the UV-B radiation and M. oryzae on the resistance physiology and gene expression of rice leaves were examined. Results revealed that UV-B radiation given before M. oryzae infection (UV-B?→?M.) significantly increased the pathogenesis-related proteins (PRs) activities of phenylalanine ammonialyase (PAL), lipoxygenase (LOX), chitinase (CHT), and β-1,3-glucanase, the resistance-related substances (flavonoids and total phenols) content, and resistance-related genes (OsPAL and OsCHT) expression, thereby improving the disease resistance of rice leaves. Simultaneous exposure to UV-B radiation and M. oryzae (UV-B/M.) significantly increased the OsLOX2 expression and the PRs activities. Exposure to UV-B radiation after M. oryzae infection (M.?→?UV-B) decreased the flavonoid content, did not improve the PRs activity, and increased OsLOX2 expression. Compound treatments of UV-B?→?M., UV-B/M., and M.?→?UV-B reduced the disease index by 62.3%, 40.2%, and 26.6%, respectively, indicating UV-B radiation inhibited the occurrence of M. oryzae disease, but its inhibitory effect weakened when it was provided after M. oryzae infection. Hence, rice responded to the compound stress of UV-B radiation and M. oryzae through a resistance-related physiological mechanism associated with the sequence of stress occurrence.     

Network-based Phenome-Genome Association Prediction by Bi-Random Walk

MotivationThe availability of ontologies and systematic documentations of phenotypes and their genetic associations has enabled large-scale network-based global analyses of the association between the complete collection of phenotypes (phenome) and genes. To provide a fundamental understanding of how the network information is relevant to phenotype-gene associations, we analyze the circular bigraphs (CBGs) in OMIM human disease phenotype-gene association network and MGI mouse phentoype-gene association network, and introduce a bi-random walk (BiRW) algorithm to capture the CBG patterns in the networks for unveiling human and mouse phenome-genome association. BiRW performs separate random walk simultaneously on gene interaction network and phenotype similarity network to explore gene paths and phenotype paths in CBGs of different sizes to summarize their associations as predictions.ResultsThe analysis of both OMIM and MGI associations revealed that majority of the phenotype-gene associations are covered by CBG patterns of small path lengths, and there is a clear correlation between the CBG coverage and the predictability of the phenotype-gene associations. In the experiments on recovering known associations in cross-validations on human disease phenotypes and mouse phenotypes, BiRW effectively improved prediction performance over the compared methods. The constructed global human disease phenome-genome association map also revealed interesting new predictions and phenotype-gene modules by disease classes.     

A robust two-way semi-linear model for normalization of cDNA microarray data

Background  

Normalization is a basic step in microarray data analysis. A proper normalization procedure ensures that the intensity ratios provide meaningful measures of relative expression values.     

Biosynthesis of fusarochromanone and its monoacetyl derivative by Fusarium equiseti.

One fluorescent compound previously named TDP-2 was isolated and purified from a rice culture of Fusarium equiseti (Alaska 2-2). Mass spectral and nuclear magnetic resonance data indicated that it is a C-3'-N-acetyl derivative of fusarochromanone, a newly discovered mycotoxin. Time course studies of synthesis of these two compounds on autoclaved rice and Czapek-Dox medium enriched with soybean peptone indicated that fusarochromanone was converted to TDP-2 in the cultures. A high concentration of peptone in the liquid medium may stimulate both fusarochromanone synthesis and its conversion to TDP-2.