Rapid on-site nucleic acid testing: On-chip sample preparation, amplification, and detection, and their integration into all-in-one systems.

As nucleic acid testing is playing a vital role in increasingly many research fields, the need for rapid on-site testing methods is also increasing. The test procedure often consists of three steps: Sample preparation, amplification, and detection. This review covers recent advances in on-chip methods for each of these three steps and explains the principles underlying related methods. The sample preparation process is further divided into cell lysis and nucleic acid purification, and methods for the integration of these two steps on a single chip are discussed. Under amplification, on-chip studies based on PCR and isothermal amplification are covered. Three isothermal amplification methods reported to have good resistance to PCR inhibitors are selected for discussion due to their potential for use in direct amplification. Chip designs and novel strategies employed to achieve rapid extraction/amplification with satisfactory efficiency are discussed. Four detection methods providing rapid responses (fluorescent, optical, and electrochemical detection methods, plus lateral flow assay) are evaluated for their potential in rapid on-site detection. In the final section, we discuss strategies to improve the speed of the entire procedure and to integrate all three steps onto a single chip; we also comment on recent advances, and on obstacles to reducing the cost of chip manufacture and achieving mass production. We conclude that future trends will focus on effective nucleic acid extraction via combined methods and direct amplification via isothermal methods.

Rapid detection of multiple resistance genes to last-resort antibiotics in Enterobacteriaceae pathogens by recombinase polymerase amplification combined with lateral flow dipstick.

The worrying emergence of multiple resistance genes to last-resort antibiotics in food animals and human populations throughout the food chain and relevant environments has been increasingly reported worldwide. Enterobacteriaceae pathogens are considered the most common reservoirs of such antibiotic resistance genes (ARGs). Thus, a rapid, efficient and accurate detection method to simultaneously screen and monitor such ARGs in Enterobacteriaceae pathogens has become an urgent need. Our study developed a recombinase polymerase amplification (RPA) assay combined with a lateral flow dipstick (LFD) for simultaneously detecting predominant resistance genes to last-resort antibiotics of Enterobacteriaceae pathogens, including mcr-1, blaNDM-1 and tet(X4). It is allowed to complete the entire process, including crude DNA extraction, amplification as well as reading, within 40 min at 37°C, and the detection limit is 101 copies/µl for mcr-1, blaNDM-1 and tet(X4). Sensitivity analysis showed obvious association of color signals with the template concentrations of mcr-1, blaNDM-1 and tet(X4) genes in Enterobacteriaceae pathogens using a test strip reader (R 2 = 0.9881, R 2 = 0.9745, and R 2 = 0.9807, respectively), allowing for quantitative detection using multiplex RPA-LFD assays. Therefore, the RPA-LFD assay can suitably help to detect multiple resistance genes to last-resort antibiotics in foodborne pathogens and has potential applications in the field.

Interactions between life expectancy and the incidence and mortality rates of cancer in China: a population-based cluster analysis.

BACKGROUND: The relationship between cancer and life expectancy is well established in both developed and developing countries. China is a vast country with significant geographical differences in population structure and healthcare, and thus provides a unique opportunity to analyze the complex relationship between life expectancy and cancer incidence and mortality rates. METHODS: Cancer data were extracted for a total of 255 units (cities or counties) from the 2013 National Central Cancer Registry. Life expectancy data at the unit level were obtained from the National Centers for Disease Control and Prevention. Linear regression analysis was used to analyze the relationship between life expectancy and crude incidence and mortality rates of cancer. In a separate analysis, life expectancy was rated as low (< 76.0 years), middle (76-80 years), or high (> 80 years). RESULTS: Overall, the cancer incidence and mortality rates positively correlated with life expectancy in both sexes (R at 0.37 and 0.50, P < 0.001). The correlation was significant for the following cancers: lung, colorectal, prostate, bladder and pancreas, as well as for lymphoma in men (R 0.36-0.58, P < 0.001), lung, breast, colorectal, thyroid, uterus, and ovary in women (R 0.18-0.51, P < 0.001). We failed to observe an association between upper gastrointestinal cancer and life expectancy. The number of cities/counties with low, middle and high life expectancy levels were 110, 101 and 44, respectively. The highest age-standardized cancer incidence rate was observed in areas with a high life expectancy level (192.83/100,000). The highest age-standardized mortality rate was in areas with the lowest life expectancy (118.44/100,000). Cancers of the stomach, liver and esophagus are major cancer types in areas with low and middle life expectancy. In contrast, areas with high life expectancy had high incidence and mortality rates of colorectal cancer, breast cancer in women and prostate cancer in men. CONCLUSIONS: Longer life expectancy is associated with higher overall cancer incidence and mortality in China. The cancer pattern also varies substantially across areas with different life expectancy levels. Life expectancy levels must be considered when developing strategies to prevent and treat cancers.

Liver cancer incidence and mortality in China: Temporal trends and projections to 2030.

OBJECTIVE: Liver cancer is one of the most common cancers and major cause of cancer deaths in China, which accounts for over 50% of new cases and deaths worldwide. The systematic liver cancer statistics including of projection through 2030 could provide valuable information for prevention and control strategies in China, and experience for other countries. METHODS: The burden of liver cancer in China in 2014 was estimated using 339 cancer registries' data selected from Chinese National Cancer Center (NCC). Incident cases of 22 cancer registries were applied for temporal trends from 2000 to 2014. The burden of liver cancer through 2030 was projected using age-period-cohort model. RESULTS: About 364,800 new cases of liver cancer (268,900 males and 95,900 females) occurred in China, and about 318,800 liver cancer deaths (233,500 males and 85,300 females) in 2014. Western regions of China had the highest incidence and mortality rates. Incidence and mortality rates decreased by about 2.3% and 2.6% per year during the period of 2000-2014, respectively, and would decrease by more than 44% between 2014 and 2030 in China. The young generation, particularly for those aged under 40 years, showed a faster down trend. CONCLUSIONS: Based on the analysis, incidence and mortality rates of liver cancer are expected to decrease through 2030, but the burden of liver cancer is still serious in China, especially in rural and western areas. Most cases of liver cancer in China can be prevented through vaccination and more prevention efforts should be focused on high risk groups.

[Epidemiological study of Helicobacter pylori infection and its risk factors in Shanghai].

OBJECTIVE: To explore the Helicobacter pylori (Hp) infection status in Shanghai and its risk factors. METHODS: A questionnaire survey including 60 items related to Hp was conducted among 1925 persons, 976 males (50.7%) and 949 females (49.3%), aged 37 +/- 11 (15 approximately 72), selected by cluster sampling in 12 rural and urban areas in Shanghai. Peripheral blood was collected to detect Hp IgG antibody so as to evaluate the past infection status and (14)C urea breath test (UBT) was performed so as to evaluate the present infection status. Fecal Hp antigen test was done in the subjects under 18 years of age. RESULTS: 1822 of the 1925 subjects (94.6%) underwent the 3 tests. were followed antibody detection and (14)C UBT and response with questionnaires. The Hp infection rate was 66.4% in general, and 68.4% in the females, somehow higher than in the males (64.3%, P = 0.067). The infection rate was different in different age groups, was the lowest in the age group of 15 approximately 19 (44.4%) and the highest 70% in age group of 20 approximately 30 (70%), then somewhat lower and gradually became higher. Socio-economic status was related to Hp infection. Hp infection was related with such factors as eating raw vegetables and fruits, and never washing raw vegetables and fruits before eating. The knowledge rate about Hp infection was only 33.2% among the respondents. Only 23.8% of the respondents knew well the transmission route of Hp. CONCLUSION: Hp infection rate is rather high in Shanghai. Hp infection is related to socio-economic status, and family dietary and sanitary habits.