Establishment and preliminary application of quantitative real-time PCR assay for the detection of SARS-CoV-2 subgenomic nucleocapsid RNA / 中华预防医学杂志

Objective: To establish a rapid and specific quantitative real-time PCR (qPCR) method for the detection of SARS-CoV-2 subgenomic nucleocapsid RNA (SgN) in patients with COVID-19 or environmental samples. Methods: The qPCR assay was established by designing specific primers and TaqMan probe based on the SARS-CoV-2 genomic sequence in Global Initiative of Sharing All Influenza Data (GISAID) database. The reaction conditions were optimized by using different annealing temperature, different primers and probe concentrations and the standard curve was established. Further, the specificity, sensitivity and repeatability were also assessed. The established SgN and genomic RNA (gRNA) qPCR assays were both applied to detect 21 environmental samples and 351 clinical samples containing 48 recovered patients. In the specimens with both positive gRNA and positive SgN, 25 specimens were inoculated on cells. Results: The primers and probes of SgN had good specificity for SARS-CoV-2. The minimum detection limit of the preliminarily established qPCR detection method for SgN was 1.5×102 copies/ml, with a coefficient of variation less than 1%. The positive rate of gRNA in 372 samples was 97.04% (361/372). The positive rates of SgN in positive environmental samples and positive clinical samples were 36.84% (7/19) and 49.42% (169/342), respectively. The positive rate and copy number of SgN in Wild strain were lower than those of SARS-CoV-2 Delta strain. Among the 25 SgN positive samples, 12 samples within 5 days of sampling time were all isolated with virus; 13 samples sampled for more than 12 days had no cytopathic effect. Conclusion: A qPCR method for the detection of SARS-CoV-2 SgN has been successfully established. The sensitivity, specificity and repeatability of this method are good.

Metabolism of terephthalic acid and its effects on CYP4B1 induction / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investgate the metabolism of terephthalic acid (TPA) in rats and its mechanism. Methods Metabolism was evaluated by incubating sodium terephthalate (NaTPA) with rat normal liver microsomes, or with microsomes pretreated by phenobarbital sodium, or with 3-methycholanthrene, or with diet control following a NADPH-generating system. The determination was performed by high performance liquid chromatography (HPLC), and the mutagenic activation was analyzed by umu tester strain Salmonella typhimurium NM2009. Expression of CYP4B1 mRNA was detected by RT-PCR. Results The amount of NaTPA (12.5-200 micromol x L(-1)) detected by HPLC did not decrease in microsomes induced by NADPH-generating system. Incubation of TPA (0.025-0.1 mmol x L(-1)) with induced or noninduced liver microsomes in an NM2009 umu response system did not show any mutagenic activation. TPA exposure increased the expression of CYP4B 1 mRNA in rat liver, kidney, and bladder.</p><p><b>CONCLUSION</b>Lack of metabolism of TPA in liver and negative genotoxic data from NM2009 study are consistent with other previous short-term tests, suggesting that the carcinogenesis in TPA feeding animals is not directly interfered with TPA itself and/or its metabolites.</p>

Effects of terephthalic acid on rat lipid metabolism / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effect of terephthalic acid (TPA) on lipid metabolism in Sprague-Dawley (SD) rats.</p><p><b>METHODS</b>Five groups of SD rats that ingested 0%, 0.04%, 0.2%, 1%, and 5% TPA, respectively, were included in a 90-day subchronic feeding study. Effects of TPA on levels of serum protein, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL), total antioxidative capability (T-AOC), superoxide dismutase (SOD) and malondialdehyde (MDA) were observed. Urine samples were collected and analyzed for concentration of ion.</p><p><b>RESULTS</b>TPA decreased the level of serum T-AOC in a dose dependent manner. The contents of serum and bladder MDA significantly decreased in 1% and 5% TPA ingestion groups. Serum CuZn superoxide dismutase (CuZnSOD) lowered in groups of 0.2%, 1%, and 5% TPA. TPA subchronic feeding had no significant influences on serum TC, LDL or HDL, but increased serum TG, TP and ALB after administration of 0.04% and/or 0.2% TPA. Concentrations of urinary Ca2+, Mg2+, Na+, and K+ were elevated in 1% and 5% TPA groups.</p><p><b>CONCLUSION</b>Antioxidative potential decreased after TPA exposure. MDA increase in serum and bladder tissues was one of the most important reactions in rats which could protect themselves against TPA impairment. The decrease of serum CuZnSOD was related to the excretion of Zn2+.</p>

Induction of bladder lesion by terephthalic acid and its mechanism / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To provide more information for rational evaluation of potential risks of terephthalic acid (TPA), we studied the effects of TPA on rats' bladders in 90 days after TPA exposure.</p><p><b>METHODS</b>Sprague Dawley rats were subdivided into five groups, ingesting 0%, 0.04%, 0.2%, 1%, and 5% TPA respectively for a sub-chronic feeding study lasting for 90 days. Urine, serum and samples of brain, liver, lung, kidney, bladder, etc. were collected and analyzed.</p><p><b>RESULTS</b>TPA ingesting decreased the value of urinary pH, and increased the contents of Ca2+, Zn2+, Mg2+, Na+, K+ in urine. The volume of 24 h urine was significantly increased in male rats in the 1% and 5% TPA groups. Urinary white sediment was found in both sexes, and its formation in male rats seemed more susceptible than that in female rats. Alpha 2u-globulin (AUG) in serum and urine of male rats was markedly increased in a dose-dependent manner. Fifteen cases of hyperplasia (simple or atypical) were determined in the 5% TPA ingesting group, 14/52 in male rats and 1/23 in female rats. Among them 3 male rats had no stone or calculus. Those with either bladder stones or hyperplasia were accompanied with urinary white sediments.</p><p><b>CONCLUSION</b>White sediment accompanied with elevated urine AUG is the basis of TPA induced urolith formation, and is also associated with TPA induced bladder epithelial cell proliferation. It can act as an early biomarker for the potential toxic effect of TPA.</p>