Preparation of the porcine secretory component and a monoclonal antibody against this protein.

Secretory component (SC) is a component of secretory IgA that is designated sIgA to distinguish it from IgA. The monoclonal antibody (MAb) against SC has been shown to be an excellent tool for the detection of the level of sIgA and for the evaluation of the efficacy of mucosal immunity. To prepare a monoclonal antibody against porcine SC, a recombinant porcine SC was expressed and purified. To develop this recombinant SC, the gene encoding the porcine SC was ligated into the pCold I vector. The recombinant vector was then transformed into Escherichia coli BL 21 (DE3), and gene expression was successfully induced by isopropyl-ß-D-thiogalactoside (IPTG). After affinity purification with Ni-NTA resin and gel recovery, the recombinant SC protein was used to immunize BALB/c mice. Finally, three hybridoma cell lines showing specific recognitions of both recombinant SC and native SC were used as stable secretors of MAbs against porcine SC and were confirmed to have no reaction to porcine IgA or IgG. The successful preparations of recombinant SC protein and MAbs provide valuable materials that can be used in the mucosal infection diagnosis for porcine disease and mucosal immune evaluation for porcine vaccine, respectively.

A systematic analysis of the global and regional burden of colon and rectum cancer and the difference between early- and late-onset CRC from 1990 to 2019.

The burden of colorectal cancer (CRC) varies substantially across different geographical locations. However, there was no further quantitative analysis of regional social development and the disease burden of CRC. In addition, the incidence of early- and late-onset CRC has increased rapidly in developed and developing regions. The main purpose of this study was to investigate the trends in CRC burden across different regions, in addition to the epidemiological differences between early and late-onset CRC and their risk factors. In this study, estimated annual percentage change (EAPC) was employed to quantify trends in age-standardized incidence rate (ASIR), mortality rate, and disability-adjusted life-years. Restricted cubic spline models were fitted to quantitatively analyze the relationship between trends in ASIR and Human Development Index (HDI). In addition, the epidemiological characteristics of early- and late-onset CRC were investigated using analyses stratified by age groups and regions. Specifically, meat consumption and antibiotic use were included to explore the differences in the risk factors for early- and late-onset CRC. The quantitative analysis showed that the ASIR of CRC was exponentially and positively correlated with the 2019 HDI in different regions. In addition, the growing trend of ASIR in recent years varied substantially across HDI regions. Specifically, the ASIR of CRC showed a significant increase in developing countries, while it remained stable or decreased in developed countries. Moreover, a linear correlation was found between the ASIR of CRC and meat consumption in different regions, especially in developing countries. Furthermore, a similar correlation was found between the ASIR and antibiotic use in all age groups, with different correlation coefficients for early-onset and late-onset CRC. It is worth mentioning that the early onset of CRC could be attributable to the unrestrained use of antibiotics among young people in developed countries. In summary, for better prevention and control of CRC, governments should pay attention to advocate self-testing and hospital visits among all age groups, especially among young people at high risk of CRC, and strictly control meat consumption and the usage of antibiotics.

[Effects of ethanol extracts of Panax notoginseng on liver metastasis of B16 melanoma grafted in mice].

OBJECTIVE: To observe the effects of ethanol extracts of Panax notoginseng on the tumor and the liver metastasis in experimental mice grafted with B16 melanoma. METHODS: B16 melanoma was transplanted in the spleen of C57BL/6 mice. The effects of different doses of ethanol extracts of Panax notoginseng on the inhibition rate of spleen tumors and the liver metastasis were observed respectively. RESULTS: The high-, medium-, and low-doses of the extracts and the interferon-alpha (IFN-alpha) can improve the quality of life of the experimental mice. The weights of spleen tumor were lower in the low- and medium-dose extracts-treated groups and the IFN-alpha-treated group than that in the normal saline (NS)-treated group (P<0.05 or P<0.01). The liver metastasis was less in the low- and medium-dose extracts-treated groups and the IFN-alpha-treated group than that in the NS-treated group (P<0.01). CONCLUSION: The ethanol extracts of Panax notoginseng can improve the quality of life of the experimental mice and inhibit the growth of tumor and the liver metastasis.