Magnitude and timing of the antiviral response determine SARS-CoV-2 replication early in infection

The interferon response is a potent antiviral defense mechanism, but its effectiveness depends on its timing relative to viral replication. Here, we report viral replication and host response kinetics in patients at the start of SARS-CoV-2 infection and explore the impact of these kinetics experimentally. In both longitudinal patient nasopharyngeal samples and airway epithelial organoids, we found that SARS-CoV-2 initially replicated exponentially with a doubling time of [~]6hr, and induced interferon stimulated genes (ISGs) with delayed timing relative to viral replication. Prior exposure to rhinovirus increased ISG levels and blocked SARS-CoV-2 replication. Conversely, inhibiting ISG induction abrogated interference by rhinovirus and enhanced SARS-CoV-2 replication rate. These results demonstrate the importance of initial interferon-mediated defenses in determining the extent to which SARS-CoV-2 can replicate at the start of infection and indicate that biological variables that alter the airway interferon response, including heterologous induction of innate immunity by other viruses, could profoundly impact SARS-CoV-2 susceptibility and transmission.

Analysis of population-based colorectal cancer screening in Guangzhou, 2011-2015.

OBJECTIVE: To analyze the detection rates of colorectal cancer (CRC) and polyps by population-based screening in Guangzhou. METHODS: From January 2011 to December 2015, the residents aged 30-79 were selected for CRC screening. The residents were conducted Questionnaires and/or FOBT to assess high-risk groups, the free colonoscopy examination was recommended, and the results were evaluated in detail. RESULTS: There were 98 927 residents involving screening, 5306 high-risk residents identified (males 1859 and females 3447), and 4713 subjects underwent colonoscopy (males 1690 and females 3023). CRC was seen in 55 individuals (males 28 and females 27), and the detection rates in male were higher than in female (P = 0.019). And the detection rates increasing with age, for people over 60 years old, were obviously higher than those younger (x2  = 18.64, P = 0.000924). The polyps were seen in 1458 (30.94%) cases， and 1420 subjects received pathological examination (adenomas 971 and non-adenomatous polyps 449). Advanced adenomas were seen in 462 cases (males 240 and females 222) and 509 cases of non-advanced adenomas (males 255 and females 254). For advanced adenomas, the detection rates in male were higher than female (14.20% vs 7.34%, P = 2.64 × 10-14 ). For the detection rates of adenomas or advanced adenomas by age, the people over 40 years were higher than younger (20.91% vs 3.61% P = 7.87 × 10-6 ; 9.94% vs 2.41%, P = 0.009). CONCLUSIONS: For Guangzhou residents, the detection rates of CRC and adenoma were 1.17% and 20.60%. The detection rates of CRC increasing with age, for people over 60 years old, were obviously higher than those younger. But for people over 40 years, the detection rate of adenoma and advanced adenoma was higher than younger. So for people over 40 years, the CRC screening is recommended.

HAND system-based four multiplex RT-PCR for simultaneous detection of four diarrhea viruses / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a one-step four multiplex reverse transcription polymerase chain reaction (RT-PCR) method based on Homo-Tag Assisted Non-Dimer System (HAND) system for simultaneous detection of 4 diarrhea viruses of rotavirus, astrovirus, norovirus and sapovirus.</p><p><b>METHODS</b>Primers were designed according to the conserved genome sequence of the 4 viruses and the homologous tail sequences were added to the 5' end. The multiplex RT-PCR system was constructed by optimizing the PCR parameters such as the concentration of universal tag primer and genome-specific Homo-Tailed primers. The specificity, stability and sensitivity of the method were evaluated systematically.</p><p><b>RESULTS</b>The 4 multiplex RT-PCR methods based on HAND system was established successfully. Specificity analysis showed no cross reaction between the 4 diarrhea viruses. The sensitivity analysis showed detection limits for rotavirus, astrovirus, norovirus and sapovirus of 48, 1.92, 9.6 and 48 pg per reaction, respectively.</p><p><b>CONCLUSION</b>The established HAND system-based multiplex RT-PCR assay allows simple, rapid, specific, sensitive, and stable for detection of the 4 common diarrhea viruses at low costs and is suitable for application in general medical laboratories.</p>

Association between APOBEC3G polymorphisms and susceptibility to chronic hepatitis B / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the association between rs185983011 single-nucleotide polymorphisms (SNP) of apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G (APOBEC3G) and the susceptibility to chronic hepatitis B.</p><p><b>METHODS</b>The blood samples were collected from 186 healthy subjects and 159 patients with chronic hepatitis B. The rs185983011 SNP was detected and genotyped by sequencing with Sanger's method to analyze the relationship between rs185983011 SNP and chronic hepatitis B.</p><p><b>RESULTS</b>Only C/C and C/T genotypes of the alleles of rs185983011 SNP were found in the tested subjects, and the C/C genotype was predominant (97.7%). The distribution frequencies of rs185983011 SNP genotypes and alleles showed no significant difference between healthy subjects and patients with chronic hepatitis B (P>0.05).</p><p><b>CONCLUSION</b>The predominant genotype of rs185983011 SNP of APOBEC3G is C/C in the tested subjects, and rs185983011 SNP does not appear to associate with the susceptibility to chronic hepatitis B.</p>