Development and evaluation of a Novel RT-PCR system for reliable and rapid SARS-CoV-2 screening of blood donations.

BACKGROUND: The ongoing outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused great global concerns. In contrast to SARS, some SARS-CoV-2-infected people can be asymptomatic or have only mild nonspecific symptoms. Furthermore, there is evidence that SARS-CoV-2 may be infectious during an asymptomatic incubation period. With the discovery that SARS-CoV-2 can be detected in plasma or serum, blood safety is worthy of consideration. STUDY DESIGN AND METHODS: We developed a nucleic acid test (NAT) screening system for SARS-CoV-2 targeting nucleocapsid protein (N) and open reading frame 1ab (ORF 1ab) gene that could screen 5076 samples every 24 hours. The 2019 novel coronavirus RNA standard was used to evaluate linearity of standard curves. Diagnostic sensitivity and reproducibility were evaluated using artificial SARS-CoV-2. Specificity was evaluated with 61 other respiratory pathogens. Diagnostic performance was evaluated by testing two sputum and nine oropharyngeal swab specimens. The reverse transcription polymerase chain reaction (RT-PCR) assay was used to screen SARS-CoV-2 RNA in blood donor specimens collected during the outbreak of SARS-CoV-2 in Chengdu. RESULTS: Limits of detection of the SARS-CoV-2 RT-PCR assay for N and ORF 1ab gene were 12.5 and 27.58 copies/mL, respectively. Intra-assay and interassay for the SARS-CoV-2 RT-PCR assay based on cycle threshold were acceptably low. No cross-reactivity was observed with other respiratory virus and bacterial isolates. The overall agreement value between the SARS-CoV-2 RT-PCR assay and clinical diagnostic results was 100%. A total of 16 287 blood specimens collected from blood donors during SARS-CoV-2 surveillance were tested negative. CONCLUSIONS: A high-throughput NAT screening system was developed for SARS-CoV-2 screening of blood donations during the outbreak of SARS-CoV-2.

The estimation of prevalence and risk factors of hepatitis B virus infection among blood donors in Chengdu, China.

The reported positive rates of hepatitis B virus surface antigen (HBsAg) among Chinese blood donors generally do not include data from pre-donation rapid tests. The aim of this study was to estimate the prevalence of serologic markers for HBsAg and risk factors among blood donors from Chengdu, China. From April 2010 to March 2011, a total of 16,875 blood donors were enrolled. Data from HBsAg tests before and after donations were collected to estimate the prevalence of HBsAg. A case-control study was conducted in 265 unique HBsAg-positive blood donors and 530 seronegative donors between January 2011 and October 2012. The odds ratio (OR) and 95% confidence interval (CI) were calculated using conditional logistic regression. The population attributable risk (PAR) was estimated. The prevalence of HBsAg was 3.17% (95%CI, 2.91-3.43%). The following risk factors were associated with HBV infection: non-vaccination for HBV (OR = 4.236; 95%CI, 2.72-6.60%), razor sharing (OR = 2.370; 95%CI, 1.46-3.84%), dental treatment (OR = 1.714; 95%CI, 1.21-2.43%), acupuncture (OR = 1.983; 95%CI, 1.20-3.28%), a family history of HBV infection (OR = 2.257; 95%CI, 1.32-3.86%), and endoscopy (OR = 2.17; 95%CI, 1.04-4.51%). The PAR values of the risk factors were 42.77%, 31.78%, 13.68%, 6.18%, 6.09%, and 2.85%, respectively, and the total PAR was 68.78%. The prevalence of HBsAg among Chinese blood donors is still high. HBV vaccinations can provide protection. Blood contact from sharing instruments is still a high risk route of transmission for HBV. Immunization programs and behavioral interventions should be used to prevent blood donation infections and improve blood safety.

Effects of statins on alpha7 nicotinic receptor, cholinesterase and alpha-form of secreted amyloid precursor peptide in SH-SY5Y cells.

In order to reveal the neuroprotective effects of statins that could be of interest for the prevention and treatment of Alzheimer's disease (AD), we investigated the expression of nicotinic acetylcholine receptors (nAChRs) detected by RT-PCR, the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) by colorimetric determination, and the levels of the alpha-form of secreted beta-amyloid precursor protein (alphaAPPs) by Western blotting in neuroblastoma (SH-SY5Y) cells exposed to lovastatin, atorvastatin, rosuvastatin and simvastatin, respectively. The results indicated that all statins studied, both lipophilic and hydrophilic, induced high expression of alpha7 nAChR, decreased cholinesterase activities, and increased alphaAPPs, which suggests that statins might play important neuroprotective roles in AD treatment.

[Protection of Tianshen Yizhi Recipe against low expression of nicotinic receptor and neurotoxicity induced by beta-amyloid peptide].

OBJECTIVE: To investigate the inhibition effects of Tianshen Yizhi Recipe (TSYZR), a compound traditional Chinese herbal medicine, on decreased expression of nicotinic acetylcholine receptor (nAChR) and the neurotoxicity as well as lipid peroxidation induced by beta-amyloid peptide (Abeta) in human SH-SY5Y neuroblastoma cells. METHODS: The SH-SY5Y cells were treated by a certain concentration of TSYZR, and then exposed to Abeta(25-35). Methyl thiazolyl tetrazolium reduction assay was carried out to understand the influences of the drugs on cellular viability. Expressions of nAChR subunits (alpha3 and alpha7) at protein and mRNA levels were detected by Western-blotting and reverse transcription polymerase chain reaction, respectively. Lipid peroxidation was measured by thiobarbituric acid to observe the capacity of antioxidant of the drugs. RESULTS: TSYZR at a safe concentration could increase alpha7 protein in the cells, inhibit decreased expressions of alpha3 and alpha7 nAChR subunit proteins, prevent lower expression of alpha7 mRNA in SH-SY5Y cells induced by Abeta, reduce the neurotoxicity and lipid peroxidation resulting from Abeta, but had no significant effect on the lower expression of alpha3 mRNA. CONCLUSIONS: TSYZR can up-regulate the expression of alpha7 nAChR subunit protein and prevent decreased expressions of nAChRs and neurotoxicity as well as lipid peroxidation induced by Abeta. This drug may play an important therapeutic role in treatment of Alzheimer disease.