OBJECTIVETo prepare and characterize monoclonal antibodies (mAb) and polyclonal antibodies against nucleocapsid (N) protein of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) and to establish antibodies-based sandwich ELISA for detecting N protein of SARS-CoV, which might apply to early diagnosis of patients with SARS-CoV infection.

METHODSBALB/c mice were immunized with purified recombinant N protein of SARS-CoV for producing mAbs, and New Zealand white rabbits were immunized for producing polyclonal antibodies. The identification of antibodies was performed using indirect enzyme-linked immunosorbent assay (ELISA), indirect fluorescent-antibody assay (IFA), and Western immunoblotting. Capturing and detecting antibodies were selected by pairing the mAbs and polyclonal antibodies one by one and an antibodies-based sandwich antigen capture ELISA was used for detecting N antigen of SARS-CoV.

RESULTSNine mAbs and hyperimmune rabbit polyclonal antibodies, specifically against SARS-CoV nucleocapsid protein were obtained. Using paired ELISA assay, three mAbs N1E8, N8E1 and N10E4 were selected as capturing antibody and rabbit polyclonal antibodies as detecting antibody then triple antibodies-based sandwich ELISA was established following horseradish peroxidase (HRP)-conjugated goat anti-rabbit immunoglobulin G. The recombinant N protein was used as a standard to establish a detection sensitivity of approximated 50 pg/ml with this assay. When tested with 420 serum specimens from serologically confirmed SARS patients, the positive rates of serum N protein were 90.1%, 23% and 0%, in which sera collected from 1 to 10 days, 11 to 20 days and beyond 21 days respectively after the onset of symptoms. The specificity of the assay was 99.86% in 715 control serum specimens. There was no cross-reaction with other respiratory viruses and coronaviruses.

CONCLUSIONSpecific and high affinity mAbs and rabbit polyclonal antibodies were obtained. By paired and optimized sandwich ELISA, a sensitive and specific antigen capture ELISA was established for detecting N antigen of SARS-CoV, which might apply to early diagnosis, source tracing and epidemiological studies of SARS.

Animals ; Antibodies, Monoclonal ; biosynthesis ; Antibodies, Viral ; blood ; Enzyme-Linked Immunosorbent Assay ; Humans ; Mice ; Mice, Inbred BALB C ; Nucleocapsid ; immunology ; Rabbits ; SARS Virus ; immunology ; isolation & purification ; Sensitivity and Specificity ; Severe Acute Respiratory Syndrome ; virology

Objective:To understand the basic nutrition situation of primary and secondary school students in the urban area of Yichun City， and to provide corresponding strategies and measures for the improvement of the nutrition of children and adolescents. Methods:A stratified sampling method was used to select the urban primary and secondary school students in 10 counties （cities， districts） in Yichun City from 2019 to 2020 for physical examinations to assess their nutritional status. Results:Among 8 921 primary and middle school students surveyed， 62（0.69%） were stunted in growth， 735（8.24%） were emaciated， 1 130（12.67%） were overweight， and 662（7.42%） were obese. The weight loss rate of primary school students was the highest （10.54%， 360/3 414）， followed by junior middle school students （7.07%， 214/3 026）， and senior high school students （6.49%， 161/2 481）. The difference was statistically significant （χ²=39.51， P<0.05）. The proportion of unbalanced nutritional status of boys was 35.66% （1 578/4 425）， which was higher than that of girls （22.49%， 1 011/4 496）， and the difference was statistically significant （χ²=187.91， P<0.01）. Conclusion:Both malnutrition and overweight/obesity exist in primary and middle school students in Yichun City. We should pay special attention to boys and lower grade students， and intervene different nutritional problems.

Objective To observe the effects of aerobic exercise on cardiac output during exercise in patients with chronic heart failure (CHF). Methods A total of 50 CHF patients ( echocardiography measured left ventricular ejection fraction ＜ 0. 49) were enrolled in the study and randomly divided into aerobic exercise group ( n = 25 ) and control group ( n = 25 ). Cardiopulmonary exercise testing (CPET) was performed. Patients of aerobic exercise group underwent aerobic exercise according to aerobic exercise prescription and exercise intensity is decided by anaerobic threshold before 10 J/s ( 1 minute before) of the oxygen consumption. After 6 supervised aerobic exercise training sessions in the hospital, patients were asked to perform the home-based aerobic exercise training. Patients in control group were required to maintain daily physical activities. CPET were reviewed 3 months later. Results Cardiac output(CO) ,peak CO, peak cardiac power output ( peak CPO), resting heart rate ( HR), heart rate at AT ( HR AT), HR peak, resting mean arterial pressure (MAP), peak MAP at baseline were similar between aerobic exercise group and control [(4. 2 ± 2. 0) L/min vs. (3. 3 ± 1.0) L/min, (6. 2 ± 2. 7 ) L/min vs. (5. 2 ± 1.8 ) L/min,( 1.8 ± 2. 9) L/min vs. (2. 0 ± 1.8 ) L/min, ( 1.3 ± 0. 5 ) J/s vs. ( 1.2 ± 0. 5 ) J/s, (76. 8 ± 13.5 ) beats/min vs. (73.4 ± 11.9 ) beats/min, ( 91.5 ± 11.3 ) beats/min vs. ( 92. 6 ± 12. 4 ) beats/min, ( 106. 0 ± 12. 9 )beats/min vs. ( 108. 3 ± 17.4) beats/min, (80. 8 ±9. 9)mm Hg( 1 mm Hg =0. 133 kPa) vs. (87. 6 ± 13.3)mm Hg, ( 98. 8 ± 12. 4 ) mm Hg vs. ( 102. 7 ± 13.9 ) mm Hg, all P ＞ 0. 05]. Compared to baseline, CO, peak CO, peak CPO, HR, HR AT, HR peak, MAP, peak MAP after 3 months were similar between aerobic exercise group and control( all P ＞ 0. 05 ). The differences between baseline and 3 months later expressed as △CO,△peak CO,△peak CPO, △HR, △HR AT, △HR peak, △MAP, △peak MAP were also similar between aerobic exercise group and control group [( - 0. 7 ± 2. 4) L/min vs. (0. 7 ± 2.0) L/min, ( 1.1 ± 2. 6 ) L/min vs.(1.4±2. 1)L/min,(0. 1 ±3.7)L/min vs. ( -0.2 ±2. 5) L/min, (0. 2 ± 1.0) J/s vs. (0.2 ±0.5)J/s,( - 0. 4 ± 7. 6) beats/min vs. ( 1.9 ± 9.9 ) beats/min, ( 3.4 ± 11.3 ) beats/min vs. ( - 2. 8 ± 7.6 )beats/min, (8. 9 ± 14. 5 )beats/min vs. (3.7 ± 14. 4)beats/min, (1.5 ± 12. 8 )mm Hg vs. ( - 1.3 ± 11.1 )mmHg,(6.4±18. 9)mm Hg vs. (1.3±12.3)mm Hg,all P＞0. 05]. Conclusion Three months aerobic exercise training did not improve cardiac output and related parameters during exercise in this cohort patients with CHF.

OBJECTIVE: To explore the mechanisms underlying the proliferative inhibition of Chinese herbal medicine Kang-Ai injection (KAI) in gastric cancer cells. METHODS: Gastric cancer cell lines MGC803 and BGC823 were treated by 0, 0.3%, 1%, 3% and 10% KAI for 24, 48 and 72 h, respectively. The cell proliferation was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The apoptosis and cell cycle were evaluated by flow cytometry. Interleukin (IL)-6 mRNA and protein expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immune sorbent assay (ELISA), respectively. The protein expression levels of cyclin A, cyclin E, cyclin B1, cyclin D1, p21, retinoblastoma (RB), protein kinase B (AKT), extracellular regulated protein kinases (ERK), signal transducer and activator of transcription (STAT) 1 and STAT3 were detected by Western blot. RESULTS: KAI inhibited the proliferation of MGC803 and BGC823 gastric cancer cells in dose- and time-dependent manner. After treated with KAI for 48 h, the proportion of G1 phase was increased, expression level of cyclin D1 and phosphorylation-RB were down-regulated, whereas the expression of p21 was up-regulated (all P<0.01). Furthermore, 48-h treatment with KAI decreased the phosphorylation level of STAT3, inhibited the mRNA and protein expressions of IL-6 (all P<0.01). IL-6 at dose of 10 ng/mL significantly attenuated the proliferative effect of both 3% and 10% KAI, and recovered KAI-inhibited STAT3 phosphorylation and cyclin D1 expression level (all P<0.01). CONCLUSION KAI exerted an anti-proliferative function by inhibiting IL-6/STAT3 signaling pathway followed by the induction of G₁ phase arrest in gastric cancer cells.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1/pharmacology* ; Humans ; Interleukin-6/metabolism* ; RNA, Messenger/metabolism* ; STAT3 Transcription Factor/metabolism* ; Stomach Neoplasms/genetics*