1.Isolation and characterization of an epidemic ON1 genotype of respiratory syncytial virus subtype A in Beijing
Xuchang SHAN ; Jiao REN ; Wei ZHANG ; Zhongxian ZHANG ; Lingfang ZHANG ; Jia LI ; Qiaohong CHU ; Jingdong SONG ; Zhihai CHEN ; Yao DENG ; Desheng ZHAI ; Wenjie TAN
Chinese Journal of Microbiology and Immunology 2025;45(1):10-16
Objective:To obtain a prevalent respiratory syncytial virus (RSV) clinical isolate in Beijing and analyze the genotype and biological characteristics of the strain.Methods:A nasopharyngeal secretion specimen was collected from a child with RSV infection in Beijing in 2023 and used for viral isolation. Viral nucleic acid was amplified using qRT-PCR. The isolated virus was identified by transmission electron microscopy, indirect immunofluorescence assay, and plaque formation assay. A phylogenetic analysis was conducted based on the whole-genome sequencing results. Virus titers were determined, and replication characteristics were analyzed. The efficacy of the isolated strain for in vitro screening of antiviral drugs was validated. Results:A clinical RSV isolate, named hRSV/C-Tan/BJ 202301, was successfully isolated, which could form syncytia in Hep-2 cells. Spherical, filamentous, and irregular virus particles were observed by electron microscopy. Immunofluorescence detection showed green fluorescence in Hep-2 cells, and plaque assay showed round plaques, which were similar to the Long strain in morphology. Genomic sequence analysis showed that it belonged to ON1 genotype. It exhibited similar cell growth kinetics characteristics with the Long strain and could be used for antiviral drug screening in vitro. Conclusions:In this study, one RSV strain is successfully isolated and identified. The biological characteristics and the phylogenetic relationship of this strain reflect the characteristics of the circulating strains in Beijing, which provides experimental material for RSV vaccine development and antiviral drug screening in China.
2.Development and application of an optimized focus-forming assay for quantitation of influenza A virus titer
Jia LI ; Qiaohong CHU ; Lingfang ZHANG ; Xuchang SHAN ; Tangqi WANG ; Ruiwen HAN ; Yujie JIANG ; Donghong WANG ; Baoying HUANG ; Yao DENG ; Wenjie TAN
Chinese Journal of Microbiology and Immunology 2025;45(1):45-52
Objective:To establish and optimize a novel method, focus forming assay (FFA), for quantitation of influenza A virus (FluA) and compare its application performance with traditional plague forming assay (PFA).Methods:The foci chromogenic effects of three peroxidase substrates in immunostaining were compared. The PFA and FFA methods were used to explore FluA incubation times and plaque morphology on 12-well plates, and to determine optimal incubation times and virus adsorption volumes for different FluA subtypes on 96-well plates. The correlation between FFA and PFA was evaluated, and the optimized FFA was applied to the in vitro antiviral efficacy analysis of Favipiravir and neutralization test against different subtypes of FluA. Results:TRUEBLUE substrate was identified as the optimal substrate for foci visualization. Compared with the PFA, the FFA showed improved sensitivity and reduced detection time in FluA titration, and good correlation was shown between the two methods′ results. By replacing the 96-well plate with the 12-well plate for FFA titration of different subtypes of FluA, the detection time was shortened, and the amount of serum samples used could be further reduced by optimizing the virus adsorption volume. The half-maximal effective concentration of favipiravir against influenza viruses assessed by the FFA and PFA methods showed no significant difference, and was consistent with the results obtained from quantitative PCR. Additionally, the focus reduction neutralization test and hemagglutination inhibition assays demonstrated strong correlation in determining antibody titers against FluA in serum neutralization assays.Conclusions:The improved FFA method developed here provides a more efficient experimental tool for FluA titration, antiviral drug screening and broad-spectrum vaccine evaluation.
3.Isolation and characterization of an epidemic ON1 genotype of respiratory syncytial virus subtype A in Beijing
Xuchang SHAN ; Jiao REN ; Wei ZHANG ; Zhongxian ZHANG ; Lingfang ZHANG ; Jia LI ; Qiaohong CHU ; Jingdong SONG ; Zhihai CHEN ; Yao DENG ; Desheng ZHAI ; Wenjie TAN
Chinese Journal of Microbiology and Immunology 2025;45(1):10-16
Objective:To obtain a prevalent respiratory syncytial virus (RSV) clinical isolate in Beijing and analyze the genotype and biological characteristics of the strain.Methods:A nasopharyngeal secretion specimen was collected from a child with RSV infection in Beijing in 2023 and used for viral isolation. Viral nucleic acid was amplified using qRT-PCR. The isolated virus was identified by transmission electron microscopy, indirect immunofluorescence assay, and plaque formation assay. A phylogenetic analysis was conducted based on the whole-genome sequencing results. Virus titers were determined, and replication characteristics were analyzed. The efficacy of the isolated strain for in vitro screening of antiviral drugs was validated. Results:A clinical RSV isolate, named hRSV/C-Tan/BJ 202301, was successfully isolated, which could form syncytia in Hep-2 cells. Spherical, filamentous, and irregular virus particles were observed by electron microscopy. Immunofluorescence detection showed green fluorescence in Hep-2 cells, and plaque assay showed round plaques, which were similar to the Long strain in morphology. Genomic sequence analysis showed that it belonged to ON1 genotype. It exhibited similar cell growth kinetics characteristics with the Long strain and could be used for antiviral drug screening in vitro. Conclusions:In this study, one RSV strain is successfully isolated and identified. The biological characteristics and the phylogenetic relationship of this strain reflect the characteristics of the circulating strains in Beijing, which provides experimental material for RSV vaccine development and antiviral drug screening in China.
4.Development and application of an optimized focus-forming assay for quantitation of influenza A virus titer
Jia LI ; Qiaohong CHU ; Lingfang ZHANG ; Xuchang SHAN ; Tangqi WANG ; Ruiwen HAN ; Yujie JIANG ; Donghong WANG ; Baoying HUANG ; Yao DENG ; Wenjie TAN
Chinese Journal of Microbiology and Immunology 2025;45(1):45-52
Objective:To establish and optimize a novel method, focus forming assay (FFA), for quantitation of influenza A virus (FluA) and compare its application performance with traditional plague forming assay (PFA).Methods:The foci chromogenic effects of three peroxidase substrates in immunostaining were compared. The PFA and FFA methods were used to explore FluA incubation times and plaque morphology on 12-well plates, and to determine optimal incubation times and virus adsorption volumes for different FluA subtypes on 96-well plates. The correlation between FFA and PFA was evaluated, and the optimized FFA was applied to the in vitro antiviral efficacy analysis of Favipiravir and neutralization test against different subtypes of FluA. Results:TRUEBLUE substrate was identified as the optimal substrate for foci visualization. Compared with the PFA, the FFA showed improved sensitivity and reduced detection time in FluA titration, and good correlation was shown between the two methods′ results. By replacing the 96-well plate with the 12-well plate for FFA titration of different subtypes of FluA, the detection time was shortened, and the amount of serum samples used could be further reduced by optimizing the virus adsorption volume. The half-maximal effective concentration of favipiravir against influenza viruses assessed by the FFA and PFA methods showed no significant difference, and was consistent with the results obtained from quantitative PCR. Additionally, the focus reduction neutralization test and hemagglutination inhibition assays demonstrated strong correlation in determining antibody titers against FluA in serum neutralization assays.Conclusions:The improved FFA method developed here provides a more efficient experimental tool for FluA titration, antiviral drug screening and broad-spectrum vaccine evaluation.
5.Updated consensus guidelines for management of moderate-to-severe atopic dermatitis in Singapore: Integrating biologics, Janus kinase inhibitors and conventional therapies.
Yik Weng YEW ; Uma ALAGAPPAN ; Derrick AW ; Nisha Suyien CHANDRAN ; Karen Jl CHOO ; Roland CHU ; Hong Yi KOH ; Mark Jean Aan KOH ; Shan Xian LEE ; Ching Yin NEOH ; Siyun Lucinda TAN ; Mark TANG ; Yong-Kwang TAY ; Seth FRANCIS-GRAHAM ; Andrew LIM ; Haur Yueh LEE
Annals of the Academy of Medicine, Singapore 2024;53(11):670-682
INTRODUCTION:
Since 2016, several therapies have been approved for treating atopic dermatitis (AD) in Singapore, including biologics, oral Janus kinase (JAK) inhibitors and topical crisaborole. This study supplements the 2016 Singapore treatment guidelines for AD, focusing on newer therapies for moderate-to-severe disease, while revisiting older treatment regimens to accommodate changes in knowledge and practice.
METHOD:
A modified Delphi panel was held, led by 2 co-chairs. The voting expert panel consisted of 12 dermatologists experienced in managing AD in Singapore. Delphi survey rounds were conducted between 24 July and 27 October 2023. Panellists indicated their agreement with drafted statements using a 5-point Likert scale. Consensus was defined as ≥80% agreement. An expert meeting was held to facilitate the consensus process between rounds 1 and 2 of voting.
RESULTS:
All expert panellists participated in both survey rounds, with a 100% response rate. Thirty-nine statements, classified into general principles, conventional treatments, biologics and JAK inhibitors, were proposed. Of these, 27 statements reached consensus at the end of round 1. After the expert meeting, 17 statements were included in round 2, of which 16 statements reached consensus. One statement did not reach consensus. Key updates are the inclusion of dupilumab and JAK inhibitors as potential first-line treatments for moderate-to-severe AD, in certain populations.
CONCLUSION
This modified Delphi study generated consensus among Singapore dermatology experts, to update treatment guidelines in moderate-to-severe atopic dermatitis. The consensus statements developed are intended to supplement the 2016 Singapore treatment guidelines for AD. Further revisions may be required when new evidence and/or treatments become available.
Dermatitis, Atopic/drug therapy*
;
Humans
;
Singapore
;
Janus Kinase Inhibitors/therapeutic use*
;
Biological Products/therapeutic use*
;
Delphi Technique
;
Consensus
;
Antibodies, Monoclonal, Humanized/therapeutic use*
;
Severity of Illness Index
;
Bridged Bicyclo Compounds, Heterocyclic/therapeutic use*
;
Dermatologic Agents/therapeutic use*
;
Practice Guidelines as Topic
;
Pyrimidines/therapeutic use*
;
Boron Compounds
7.Evaluation of a group family-based intervention programme for adolescent obesity: the LITE randomised controlled pilot trial.
Chu Shan Elaine CHEW ; Jean Yin OH ; Kumudhini RAJASEGARAN ; Seyed Ehsan SAFFARI ; Chee Ming Micheal LIM ; Siew Choo LIM ; Shiling TAN ; Siobhan KELLY
Singapore medical journal 2021;62(1):39-47
INTRODUCTION:
This study aimed to evaluate the LITE (Lifestyle Intervention for TEenagers) group programme, a family-based behavioural lifestyle intervention for overweight and obese adolescents.
METHODS:
We conducted a two-arm randomised controlled trial that recruited overweight and obese adolescents who attended a tertiary care weight management clinic. Participants were randomised to the LITE programme or usual care. The primary outcome assessed was body mass index (BMI) z-score. Secondary outcomes of anthropometric measurements, metabolic profile, parenting and adolescents' perception of family support were measured at baseline, three months and six months. Feasibility and acceptability of the LITE programme were also evaluated.
RESULTS:
61 adolescents were enrolled, with 31 in the LITE programme and 30 in usual care. At three months, participants in the programme had a greater reduction in weight (-0.18 ± 2.40 kg vs. 1.48 ± 1.97 kg; p = 0.107), waist circumference (-1.0 ± 3.1 cm vs. 2.4 ± 2.7 cm; p = 0.016), waist-height ratio (-0.01 ± 0.02 vs. 0.01 ± 0.02; p = 0.040) and systolic blood pressure (-3.8 ± 13.7 vs. 5.7 ± 13.1; p = 0.119) compared to the usual care group. There was no significant difference in BMI z-score. At six months, there were significant improvements in adolescents' perception of family support for eating habits in the LITE group compared to the usual care group. The LITE programme had a good attendance rate of 67.7% and was well received.
CONCLUSION
The LITE programme showed feasibility and short-term clinical effectiveness in improving some clinical outcomes and improved adolescents' perception of family support.
8.Pancreatic and duodenal homeobox-1 in pancreatic ductal adenocarcinoma and diabetes mellitus
Zhen-Chu TANG ; Yi CHU ; Yu-Yong TAN ; Jing LI ; Shan GAO
Chinese Medical Journal 2020;133(3):344-350
Diabetes mellitus and pancreatic ductal adenocarcinoma are two common diseases worldwidely which are both derived from different components of pancreas. The pancreatic and duodenal homeobox-1 (PDX1) is an essential transcription factor for the early development of pancreas that is required for the differentiation of all pancreatic cell lineages. Current evidence suggests an important role of PDX1 in both the origin and progression of pancreatic diseases. In this review, we discussed recent studies of PDX1 in diabetes mellitus and pancreatic cancer, and the therapeutic strategies derived from this transcription factor.
9. Anticancer effect of Psidium guajava (Guava) leaf extracts against colorectal cancer through inhibition of angiogenesis
Bronwyn LOK ; Hussein M. BAHARETHA ; V. Mansoureh NAZARI ; A.M.S. Abdul MAJID ; Doblin SANDAI ; Hussein M. BAHARETHA ; Muhammad ASIF ; Chu Shan TAN ; A.M.S. Abdul MAJID
Asian Pacific Journal of Tropical Biomedicine 2020;10(7):293-307
Objective: To evaluate the anti-angiogenic and anticancer activities of Psidium guajava leaf extracts against angiogenesis-dependent colorectal cancer. Methods: Three extracts were produced using distilled water, ethanol, and n-hexane as solvents. The extracts were physically characterised through gas chromatography-mass spectrometry, ultraviolet-visible spectroscopy, and Fourier transform infrared spectroscopy. Their antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl, total phenolic content, and total flavonoid content assays. To assess their anti-angiogenic activity, cell viability and rat aortic ring assays were conducted, while cell migration, tube formation, colony formation, and VEGF ELISA assays were conducted to elucidate their effects on different aspects of angiogenesis. Molecular docking was used to assess the anti- angiogenic potential of some possible compounds in the extracts. Tumour spheroid assay was used to assess the extracts' potential as a treatment for colorectal cancer. Results: The ethanol extract showed the best antioxidant activity. The distilled water and ethanol extracts exhibited more inhibitory activity against EA.hy926 cell viability and aortic ring microvessel growth. In addition, the ethanol extract performed significantly better than the distilled water extract against cell migration and colony formation, and VEGF expression of the cells was suppressed by the ethanol extract. Both the distilled water and ethanol extracts showed significant inhibitory effect on EA.hy926 tube formation and tumour spheroids consisting of EA.hy926 and HCT116 cells. The ethanol extract contained β-caryophyllene and β-elemene by phytochemical analysis and subsequent docking studies, which may contribute to its anti-angiogenic activity. Conclusions: The ethanol extract of Psidium guajava has potential in the treatment of colorectal cancer through the inhibition of angiogenesis.
10.Effects of needling acupoints at different nerve segments on oxytocin neurons in rat's hypothalamic paraventricular nucleus and intragastric pressure
Chun-Yan YONG ; Shu CHEN ; Heng CHEN ; Xiao CHU ; Chao ZHANG ; Cheng TAN ; Lan YE ; Jiang-Shan LI
Journal of Acupuncture and Tuina Science 2019;17(5):297-304
Objective:To compare and explore the effects of needling acupoints at different nerve segmentson the oxytocin (OT) neurons in the paraventricular nucleus of hypothalamus (PVN) and the intragastric pressure, and discuss the possible mechanisms. Methods: Thirty-two healthy adult Sprague-Dawley (SD) rats were numbered and divided into 4 groups according to the random number table, a Zusanli (ST 36) group, a Neiguan (PC 6) group, a Weishu (BL 21) group and a control group, with 8 rats in each group. Except the control group, rats in the other three groups received acupuncture at the corresponding acupoints. To observe the differences in double-labeled OT neurons and c-fos neurons of the hypothalamic PVN and the intragastric pressure after acupuncture among the three groups of needling acupoints at different nerve segments. Results:Compared with the control group, the numbers of double-labeled cells in the PVN of the Zusanli (ST 36) group and the Neiguan (PC 6) group decreased significantly, while the intragastric pressure increased significantly (allP<0.05), and the inter-group differences were statistically significant (P<0.05). The intragastric pressure in the Weishu (BL 21) group decreased significantly, and the inter-group difference was statistically significant (P<0.05). Compared with the Weishu (BL 21) group, the numbers of OT/c-fos double-labeled cells in PVN of the Zusanli (ST 36) group and the Neiguan (PC 6) group decreased significantly, and the intragastric pressure increased significantly, the inter-group differences were statistically significant (allP<0.01). Conclusion:Acupoints at different nerve segments have different regulation effects on intragastric pressure. The difference may be related to the different nerve conduction pathways by acupoints at different nerve segments in regulating the intragastric pressure. The PVN may be one common integration center for the regulation of gastric function in the three acupoints [Zusanli (ST 36), Neiguan (PC 6) and Weishu (BL 21)] at different nerve segments.

Result Analysis
Print
Save
E-mail