A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chloride...A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.展开更多
Recently increasing concerns from the scientists and public have been paid for seawater pollution due to tetracycline(TC)overuse in maricultural area.However,there are few methods or instruments that can be used for s...Recently increasing concerns from the scientists and public have been paid for seawater pollution due to tetracycline(TC)overuse in maricultural area.However,there are few methods or instruments that can be used for specific and rapid detection of this antibiotic in seawater.In this study,the colloidal gold immunochromatographic assay(CG-ICA)was used to achieve this goal.A commercialized monoclonal antibody against TC(anti-TC mAb)was selected because of its higher sensitivity(half-maximal inhibitory concentration of 2.38μgL^(-1)).The prepared CG particles(average diameter of 20 nm)were used to label anti-TC mAb at pH 8.0.The conjugate pad was formed by spraying the CG-labeled anti-TC mAb on a glass fibre membrane followed by proper dryness.The test pad was made by immobilizing artificial antigen and anti-mouse mAb in the test line and the control line,respectively,in a nitrocellulose membrane.The test strip,assembled with sample pad,conjugate pad,test pad and absorbent pad,could be used to detect TC during seawater sample flowing through these components in turn.The results could be observed by the naked eye in 10min.The visible limit of detection(vLOD)was 20μgL^(-1) for TC in seawater.The CG-ICA test results were in good agreement with those of liquid chromatography-tandem mass spectrometry(LC-MS/MS).The assay also showed that,oxytetracycline(OTC)and chlortetracycline(CTC),as the structural analogues of TC,did not interfere with TC determination.Furthermore,the TC concentration given by test strip could not be affected by the fluctuation of temperature(10℃–30℃),pH(7–9)and salinity(0–40)of seawater.Therefore,CG-ICA is a suitable tool for rapid,on-site,and semi-quantitative detection of TC in seawater.展开更多
AIM:To report a novel splicing mutation in the RPGR gene(encoding retinitis pigmentosa GTPase regulator)in a three-generation Chinese family with X-linked retinitis pigmentosa(XLRP).METHODS:Comprehensive ophthalmic ex...AIM:To report a novel splicing mutation in the RPGR gene(encoding retinitis pigmentosa GTPase regulator)in a three-generation Chinese family with X-linked retinitis pigmentosa(XLRP).METHODS:Comprehensive ophthalmic examinations including best corrected visual acuity,fundus photography,vision field,and pattern-visual evoked potential were performed to identify the disease phenotype of a six-yearold boy from the family(proband).Genomic DNA was extracted from peripheral blood of five available members of the pedigree.Whole-exome sequencing(WES),Sanger sequencing,and pSPL3-based exon trapping were used to investigate the aberrant splicing of RPGR.Human Splice Finder v3.1 and NNSPLICE v0.9 were used for in silico prediction of splice site variants.RESULTS:The proband was diagnosed as having retinitis pigmentosa(RP).He had severe symptoms with early onset.A novel splicing mutation,c.619+1G>C in RPGR was identified in the proband by WES and in four family members by Sanger sequencing.Minigene splicing assays verified that c.619+1G>C in RPGR would result in the formation of a damaging alternative transcript in which the last 91 bp of exon 6 were skipped,leading to the subsequent deletion of 623 correct amino acids(c.529_619del p.Val177Glnfs*16).CONCLUSION:We identify a novel splice donor site mutation causing aberrant splicing of RPGR.Our findings add to the catalog of pathological mutations of RPGR and further emphasize the functional importance of RPGR in RP pathogenesis and its complex clinical phenotypes.展开更多
Nitrogen fixation is one of the most important sources of new nitrogen in the ocean and thus profoundly affects the nitrogen and carbon biogeochemical processes.The distribution,controlling factors,and flux of N2 fixa...Nitrogen fixation is one of the most important sources of new nitrogen in the ocean and thus profoundly affects the nitrogen and carbon biogeochemical processes.The distribution,controlling factors,and flux of N2 fixation in the global ocean remain uncertain,partly because of the lack of methodological uniformity.The^(15)N_(2)tracer assay(the original bubble method→the^(15)N_(2)-enriched seawater method→the modified bubble method)is the mainstream method for field measurements of N2 fixation rates(NFRs),among which the original bubble method is the most frequently used.However,accumulating evidence has suggested an underestimation of NFRs when using this method.To improve the availability of previous data,we compared NFRs measured by three^(15)N_(2)tracer assays in the South China Sea.Our results indicate that the relationship between NFRs measured by the original bubble method and the^(15)N_(2)-enriched seawater method varies obviously with area and season,which may be influenced by incubation time,diazotrophic composition,and environmental factors.In comparison,the relationship between NFRs measured by the original bubble method and the modified bubble method is more stable,indicating that the N2 fixation rates based on the original bubble methods may be underestimated by approximately 50%.Based on this result,we revised the flux of N2 fixation in the South China Sea to 40 mmol/(m2·a).Our results improve the availability and comparability of literature NFR data in the South China Sea.The comparison of the^(15)N_(2)tracer assay for NFRs measurements on a larger scale is urgently necessary over the global ocean for a more robust understanding of the role of N2 fixation in the marine nitrogen cycle.展开更多
Introduction: The Central African Republic is one of the 30 high Tuberculosis burden countries in the world, with an incidence of 540 cases per 100,000 population and a mortality of 91 deaths per 100,000 population. S...Introduction: The Central African Republic is one of the 30 high Tuberculosis burden countries in the world, with an incidence of 540 cases per 100,000 population and a mortality of 91 deaths per 100,000 population. Since 2020, following WHO recommendations, the National Reference Laboratory for Tuberculosis has been using the Xpert<sup>®</sup> MTB/RIF assay as a first-line diagnostic test for the early detection of Drug Resistance Tuberculosis. The goal of this study was to evaluate the contribution of the Xpert<sup>®</sup> MTB/RIF assay to the surveillance of rifampicin resistance in new and previously treated tuberculosis cases. Materials and Methods: The data relative to the Xpert<sup>®</sup> MTB/RIF assay carried out on various categories of tuberculosis patients registered at the National Reference Laboratory for Tuberculosis in 2020 were analyzed retrospectively. The categories of tuberculosis patients were new cases, failed treatment cases, relapse cases, lost-to-follow-up cases and multidrug-resistant tuberculosis contact cases. Results: A total of 1404 tuberculosis patients were registered at the NRL-TB in 2020;the mean age was 39.2 years (2 - 90 years) and the male-to-female sex ratio was 1.16:1. Overall, 32.7% (454/1404) proved infected with tuberculosis, of which 22.5% (102/454) cases showed resistance to rifampicin. The primary resistance rate was 9.1% (27/298) and the secondary resistance rate was 46.6% (75/161). Treatment failures and relapsed cases were significantly associated with rifampicin resistance (p 0.005). Conclusion: Large-scale use of Xpert<sup>®</sup> MTB/RIF, especially in the provinces of the Central African Republic, will help the Ministry of Health to better control Drug Resistance Tuberculosis in the country.展开更多
A novel coronavirus of zoonotic origin(SARSCoV-2)has recently been recognized in patients with acute respiratory disease.COVID-19 causative agent is structurally and genetically similar to SARS and bat SARS-like coron...A novel coronavirus of zoonotic origin(SARSCoV-2)has recently been recognized in patients with acute respiratory disease.COVID-19 causative agent is structurally and genetically similar to SARS and bat SARS-like coronaviruses.The drastic increase in the number of coronavirus and its genome sequence have given us an unprecedented opportunity to perform bioinformatics and genomics analysis on this class of viruses.Clinical tests like PCR and ELISA for rapid detection of this virus are urgently needed for early identification of infected patients.However,these techniques are expensive and not readily available for point-of-care(POC)applications.Currently,lack of any rapid,available,and reliable POC detection method gives rise to the progression of COVID-19 as a horrible global problem.To solve the negative features of clinical investigation,we provide a brief introduction of the general features of coronaviruses and describe various amplification assays,sensing,biosensing,immunosensing,and aptasensing for the determination of various groups of coronaviruses applied as a template for the detection of SARS-CoV-2.All sensing and biosensing techniques developed for the determination of various classes of coronaviruses are useful to recognize the newly immerged coronavirus,i.e.,SARS-CoV-2.Also,the introduction of sensing and biosensing methods sheds light on the way of designing a proper screening system to detect the virus at the early stage of infection to tranquilize the speed and vastity of spreading.Among other approaches investigated among molecular approaches and PCR or recognition of viral diseases,LAMP-based methods and LFAs are of great importance for their numerous benefits,which can be helpful to design a universal platform for detection of future emerging pathogenic viruses.展开更多
Recombinant batroxobin(S3101)is a thrombin-like serine protease that binds to fibrinogen or is taken up by the reticuloendothelial system.A literature survey showed no adequate method that could determine sufficient c...Recombinant batroxobin(S3101)is a thrombin-like serine protease that binds to fibrinogen or is taken up by the reticuloendothelial system.A literature survey showed no adequate method that could determine sufficient concentrations to evaluate pharmacokinetic parameters for phase I clinical studies.Therefore,a sensitive method is urgently needed to support the clinical pharmacokinetic evaluation of S3101.In this study,a sensitive bioanalytical method was developed and validated,using a Quanterix single molecular array(Simoa)assay.Moreover,to thoroughly assess the platform,enzyme-linked immunosorbent assay and electrochemiluminescence assay were also developed,and their performance was compared with that of this novel technology platform.The assay was validated in compliance with the current guidelines.Measurements with the Simoa assay were precise and accurate,presenting a valid assay range from 6.55 to 4000 pg/mL.The intra-and inter-run accuracy and precision were within-19.3%to 15.3%and 5.5%to 17.0%,respectively.S3101 was stable in human serum for 280 days at-20℃and-70℃,for 2 h prior to pre-treatment and 24 h post pre-treatment at room temperature(22℃-28℃),respectively,and after five and two freeze-thaw cycles at-70℃and-20oC,respectively.The Simoa assay also demonstrated sufficient dilution linearity,assay sensitivity,and parallelism for quantifying S3101 in human serum.The Simoa assay is a sensitive and adequate method for evaluating the pharmacokinetic parameters of S3101 in human serum.展开更多
Two rapid,sensitive and reliable immunoassay methods,namely competitive indirect enzyme-linked immunosorbent assay(CI- ELISA)and colloidal gold-based immunochromatographic assay(CGIA),were developed to detect ofloxaci...Two rapid,sensitive and reliable immunoassay methods,namely competitive indirect enzyme-linked immunosorbent assay(CI- ELISA)and colloidal gold-based immunochromatographic assay(CGIA),were developed to detect ofloxacin(OFL).The linear range of the CI-ELISAwas from 0.5 to 128 ng/mL with a limit of detection(LOD)of 0.35 ng/mL.Good recoveries were obtained in analyzing simulated swine urine samples.The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min,and test results were read visually without any instrument.展开更多
A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELI...A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 2 0.6703;however,the correlation between MPs-CLEIA and ECLIA (R 2 0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R 2 0.6866).展开更多
BACKGROUND Current diagnosis of hepatitis C virus(HCV)infection requires two sequential steps:testing for anti-HCV followed by HCV RNA PCR to confirm viremia.We have developed a highly sensitive and specific HCV-antig...BACKGROUND Current diagnosis of hepatitis C virus(HCV)infection requires two sequential steps:testing for anti-HCV followed by HCV RNA PCR to confirm viremia.We have developed a highly sensitive and specific HCV-antigens enzyme immunoassay(HCV-Ags EIA)for one-step diagnosis of viremic HCV infection.AIM To assess the clinical application of the HCV-Ags EIA in one-step diagnosis of viremic HCV infection in human immunodeficiency virus(HIV)-coinfected individuals.METHODS The study blindly tested HCV-Ags EIA for its performance in one-step diagnosing viremic HCV infection in 147 sera:10 without HCV or HIV infection;54 with viremic HCV monoinfection;38 with viremic HCV/HIV coinfection;and 45 with viremic HCV and non-viremic HIV coinfection.RESULTS Upon decoding,it was 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR test.In five sera with HCV infection,HCV RNA was as low as 50-59 IU/mL,and four out of five tested positive for HCV-Ags EIA.Likewise,it was also 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR in 83 sera with HCV and HIV coinfection,regardless if HIV infection was active or not.CONCLUSION The modified HCV-Ags EIA has a lower detection limit equivalent to serum HCV RNA levels of approximately 100 IU/mL.It is highly sensitive and specific in the setting of HIV coinfection,regardless of HIV infection status and CD4 count.These data support the clinical application of the HCV-Ags EIA in one-step diagnosis of HCV infection in HIV-infected individuals.展开更多
Objective:To compare limiting dilution assay and real-time PCR methods in Leishmania tropica parasite load measurement in vaccinated mice.Methods:BALB/c mice were vaccinated by Leishmania tropica soluble Leishmania an...Objective:To compare limiting dilution assay and real-time PCR methods in Leishmania tropica parasite load measurement in vaccinated mice.Methods:BALB/c mice were vaccinated by Leishmania tropica soluble Leishmania antigen or recombinant Leishmania tropica stressinducible protein-1 with/without adjuvant.After three vaccinations,mice were challenged by Leishmania tropica promastigotes.Two months after challenge,the draining lymph nodes of mice footpad were removed and parasite load was assayed by limiting dilution assay and real-time PCR methods.Limiting dilution assay was done by diluting tissue samples to extinction in a biphasic medium.For real-time PCR,DNA of the lymph nodes was extracted,equal dilutions of each sample were prepared and hot-start real-time PCR was done using appropriate primers.The data of the two methods were compared by appropriate statistical methods.Results:Both methods were able to measure different levels of parasite load in vaccinated/unvaccinated mice.In addition,wherever parasite load of a group was estimated high(or low)by one method,the estimated parasite load by another method was the same,although statistically significant differences were found between some groups.Conclusions:Both methods lead to approximately similar results in terms of differentiating parasite load of the experimental groups.However,due to the lower errors and faster process,the real-time PCR method is preferred.展开更多
Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(F.limonia).Methods:Qualitative phytochemical analysis of extracts,fr...Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(F.limonia).Methods:Qualitative phytochemical analysis of extracts,fractions or compound was performed by means of thin layer chromatography and spectroscopic assays.The%purity of compound was measured by analytical HPLC.Extracts,fractions or compound have been individually evaluated for their cytotoxicity effects(10,20,100,250,500,750 and 1 000 μg/mL).Based on the inhibitory concentration(IC_(50)) obtained from the cell viability assay,graded concentrations of extracts,fractions or isolated compound were assessed(10,20,50,100,200 μg/mL) for its hepatoprotective potential against CCl_4-induced hepatotoxicity by monitoring activity levels of serum glutamatic pyruvatic transaminase(SGPT) and serum glutamic oxaloacetic transaminase(SGOT).Results:Results indicated that the methanol extract of F.limonia was non-toxic and hepatoprotective in nature as compared with the petroleum ether extract.The acetone fraction of methanolic extract also showed similar properties but the subsequent two fractions were cytotoxic.However,the pure compound isolated from the penultimate fraction of methanolic extract was non-toxic and hepatoprotective in nature.Biochemical investigations(SCOT,SCPT) further corroborated these cytological observations.Conclusions:It can be concluded from this study that F.limonia methanol extract,some fractions and pure isolated compound herein exhibit hepatoprotective activity.However,cytotoxicity recorded in the penultimate fraction and investigation of structural details of pure compound warrants further study.展开更多
INTRODUCTION The hepatitis A virus specific immunoglobulin M(IgM)antibody is a specific serological marker forearly diagnosis of hepatitis A..At present,themethods used at home or abroad for detecting anti-HAV IgM are...INTRODUCTION The hepatitis A virus specific immunoglobulin M(IgM)antibody is a specific serological marker forearly diagnosis of hepatitis A..At present,themethods used at home or abroad for detecting anti-HAV IgM are RIA,ELISA and SPHAI.The dotimmunogold combination assay that has beendeveloped since 1989 is a new technique with theproperty of simple and rapid immunologicaldetection,by using the red colloidal gold particles tolabel the antibodies as indicator,and the展开更多
文摘A rapid, straightforward, sensitive, efficient, and cost-effective reverse-phase high-performance liquid chromatographic method was employed for the simultaneous determination of Sorbitol, Sodium Lactate, and Chlorides in a drug solution for infusion. Sorbitol, Sodium lactate, and Chloride are all officially recognized in the USP monograph. Assay methods are provided through various techniques, with titrations being ineffective for trace-level quantification. Alternatively, IC, AAS, and ICP-MS, though highly accurate, are costly and often unavailable to most testing facilities. When considering methods, it’s important to prioritize both quality control requirements and user-friendly techniques. A simple HPLC simultaneous method was developed for the quantification of Chlorides, Sorbitol, and Sodium Lactate with a shorter run time. The separation utilized a Shimpack SCR-102(H) ion exclusion analytical column (7.9 mm × 300 mm, 7 μm), with a flow rate of 0.6 mL per min. The column compartment temperature was maintained at 40°C, and the injection volume was set at 10 μL, with detection at 200 nm. All measurements were conducted in a 0.1% solution of phosphoric acid. The analytical curves demonstrated linearity (r > 0.9999) in the concentration range of 0.79 to 3.8 mg per mL for Sodium Lactate (SL), 0.16 to 0.79 mg per mL for Sodium Chloride (SC), and 1.5 to 7.2 mg per mL for Sorbitol. Validation of the developed method followed the guidelines of the International Conference on Harmonization (ICH Q2B) and USP. The method exhibited precision, robustness, accuracy, and selectivity. In accelerated stability testing over 6 months, no significant variations were observed in organoleptic analysis and pH. Consequently, the developed method is deemed suitable for routine quality control analyses, enabling the simultaneous determination of Sodium Lactate, Sodium Chloride, and Sorbitol in pharmaceutical formulations and infusions.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(No.42077335).
文摘Recently increasing concerns from the scientists and public have been paid for seawater pollution due to tetracycline(TC)overuse in maricultural area.However,there are few methods or instruments that can be used for specific and rapid detection of this antibiotic in seawater.In this study,the colloidal gold immunochromatographic assay(CG-ICA)was used to achieve this goal.A commercialized monoclonal antibody against TC(anti-TC mAb)was selected because of its higher sensitivity(half-maximal inhibitory concentration of 2.38μgL^(-1)).The prepared CG particles(average diameter of 20 nm)were used to label anti-TC mAb at pH 8.0.The conjugate pad was formed by spraying the CG-labeled anti-TC mAb on a glass fibre membrane followed by proper dryness.The test pad was made by immobilizing artificial antigen and anti-mouse mAb in the test line and the control line,respectively,in a nitrocellulose membrane.The test strip,assembled with sample pad,conjugate pad,test pad and absorbent pad,could be used to detect TC during seawater sample flowing through these components in turn.The results could be observed by the naked eye in 10min.The visible limit of detection(vLOD)was 20μgL^(-1) for TC in seawater.The CG-ICA test results were in good agreement with those of liquid chromatography-tandem mass spectrometry(LC-MS/MS).The assay also showed that,oxytetracycline(OTC)and chlortetracycline(CTC),as the structural analogues of TC,did not interfere with TC determination.Furthermore,the TC concentration given by test strip could not be affected by the fluctuation of temperature(10℃–30℃),pH(7–9)and salinity(0–40)of seawater.Therefore,CG-ICA is a suitable tool for rapid,on-site,and semi-quantitative detection of TC in seawater.
基金Supported by National Natural Science Foundation of China(No.31751003)Natural Science Foundation of Zhejiang Province(No.LY20H120009)+1 种基金Health Commission of Zhejiang Province(No.2022KY168)Beijing Bethune Charitable Foundation(No.BJ-GY2021013J).
文摘AIM:To report a novel splicing mutation in the RPGR gene(encoding retinitis pigmentosa GTPase regulator)in a three-generation Chinese family with X-linked retinitis pigmentosa(XLRP).METHODS:Comprehensive ophthalmic examinations including best corrected visual acuity,fundus photography,vision field,and pattern-visual evoked potential were performed to identify the disease phenotype of a six-yearold boy from the family(proband).Genomic DNA was extracted from peripheral blood of five available members of the pedigree.Whole-exome sequencing(WES),Sanger sequencing,and pSPL3-based exon trapping were used to investigate the aberrant splicing of RPGR.Human Splice Finder v3.1 and NNSPLICE v0.9 were used for in silico prediction of splice site variants.RESULTS:The proband was diagnosed as having retinitis pigmentosa(RP).He had severe symptoms with early onset.A novel splicing mutation,c.619+1G>C in RPGR was identified in the proband by WES and in four family members by Sanger sequencing.Minigene splicing assays verified that c.619+1G>C in RPGR would result in the formation of a damaging alternative transcript in which the last 91 bp of exon 6 were skipped,leading to the subsequent deletion of 623 correct amino acids(c.529_619del p.Val177Glnfs*16).CONCLUSION:We identify a novel splice donor site mutation causing aberrant splicing of RPGR.Our findings add to the catalog of pathological mutations of RPGR and further emphasize the functional importance of RPGR in RP pathogenesis and its complex clinical phenotypes.
基金The National Natural Science Foundation of China under contract Nos 42076042 and 41721005the Fund of Ministry of Science and Technology of China under contract No.2017FY201403the Fund of China Ocean Mineral Resources R&D Association under contract No.DY135-13-E2-03.
文摘Nitrogen fixation is one of the most important sources of new nitrogen in the ocean and thus profoundly affects the nitrogen and carbon biogeochemical processes.The distribution,controlling factors,and flux of N2 fixation in the global ocean remain uncertain,partly because of the lack of methodological uniformity.The^(15)N_(2)tracer assay(the original bubble method→the^(15)N_(2)-enriched seawater method→the modified bubble method)is the mainstream method for field measurements of N2 fixation rates(NFRs),among which the original bubble method is the most frequently used.However,accumulating evidence has suggested an underestimation of NFRs when using this method.To improve the availability of previous data,we compared NFRs measured by three^(15)N_(2)tracer assays in the South China Sea.Our results indicate that the relationship between NFRs measured by the original bubble method and the^(15)N_(2)-enriched seawater method varies obviously with area and season,which may be influenced by incubation time,diazotrophic composition,and environmental factors.In comparison,the relationship between NFRs measured by the original bubble method and the modified bubble method is more stable,indicating that the N2 fixation rates based on the original bubble methods may be underestimated by approximately 50%.Based on this result,we revised the flux of N2 fixation in the South China Sea to 40 mmol/(m2·a).Our results improve the availability and comparability of literature NFR data in the South China Sea.The comparison of the^(15)N_(2)tracer assay for NFRs measurements on a larger scale is urgently necessary over the global ocean for a more robust understanding of the role of N2 fixation in the marine nitrogen cycle.
文摘Introduction: The Central African Republic is one of the 30 high Tuberculosis burden countries in the world, with an incidence of 540 cases per 100,000 population and a mortality of 91 deaths per 100,000 population. Since 2020, following WHO recommendations, the National Reference Laboratory for Tuberculosis has been using the Xpert<sup>®</sup> MTB/RIF assay as a first-line diagnostic test for the early detection of Drug Resistance Tuberculosis. The goal of this study was to evaluate the contribution of the Xpert<sup>®</sup> MTB/RIF assay to the surveillance of rifampicin resistance in new and previously treated tuberculosis cases. Materials and Methods: The data relative to the Xpert<sup>®</sup> MTB/RIF assay carried out on various categories of tuberculosis patients registered at the National Reference Laboratory for Tuberculosis in 2020 were analyzed retrospectively. The categories of tuberculosis patients were new cases, failed treatment cases, relapse cases, lost-to-follow-up cases and multidrug-resistant tuberculosis contact cases. Results: A total of 1404 tuberculosis patients were registered at the NRL-TB in 2020;the mean age was 39.2 years (2 - 90 years) and the male-to-female sex ratio was 1.16:1. Overall, 32.7% (454/1404) proved infected with tuberculosis, of which 22.5% (102/454) cases showed resistance to rifampicin. The primary resistance rate was 9.1% (27/298) and the secondary resistance rate was 46.6% (75/161). Treatment failures and relapsed cases were significantly associated with rifampicin resistance (p 0.005). Conclusion: Large-scale use of Xpert<sup>®</sup> MTB/RIF, especially in the provinces of the Central African Republic, will help the Ministry of Health to better control Drug Resistance Tuberculosis in the country.
基金Nanjing Forestry University[Grant Nos.163020139,164020818,163020217 and 16302023]National Natural Science Foundation of China(5201101466).
文摘A novel coronavirus of zoonotic origin(SARSCoV-2)has recently been recognized in patients with acute respiratory disease.COVID-19 causative agent is structurally and genetically similar to SARS and bat SARS-like coronaviruses.The drastic increase in the number of coronavirus and its genome sequence have given us an unprecedented opportunity to perform bioinformatics and genomics analysis on this class of viruses.Clinical tests like PCR and ELISA for rapid detection of this virus are urgently needed for early identification of infected patients.However,these techniques are expensive and not readily available for point-of-care(POC)applications.Currently,lack of any rapid,available,and reliable POC detection method gives rise to the progression of COVID-19 as a horrible global problem.To solve the negative features of clinical investigation,we provide a brief introduction of the general features of coronaviruses and describe various amplification assays,sensing,biosensing,immunosensing,and aptasensing for the determination of various groups of coronaviruses applied as a template for the detection of SARS-CoV-2.All sensing and biosensing techniques developed for the determination of various classes of coronaviruses are useful to recognize the newly immerged coronavirus,i.e.,SARS-CoV-2.Also,the introduction of sensing and biosensing methods sheds light on the way of designing a proper screening system to detect the virus at the early stage of infection to tranquilize the speed and vastity of spreading.Among other approaches investigated among molecular approaches and PCR or recognition of viral diseases,LAMP-based methods and LFAs are of great importance for their numerous benefits,which can be helpful to design a universal platform for detection of future emerging pathogenic viruses.
文摘Recombinant batroxobin(S3101)is a thrombin-like serine protease that binds to fibrinogen or is taken up by the reticuloendothelial system.A literature survey showed no adequate method that could determine sufficient concentrations to evaluate pharmacokinetic parameters for phase I clinical studies.Therefore,a sensitive method is urgently needed to support the clinical pharmacokinetic evaluation of S3101.In this study,a sensitive bioanalytical method was developed and validated,using a Quanterix single molecular array(Simoa)assay.Moreover,to thoroughly assess the platform,enzyme-linked immunosorbent assay and electrochemiluminescence assay were also developed,and their performance was compared with that of this novel technology platform.The assay was validated in compliance with the current guidelines.Measurements with the Simoa assay were precise and accurate,presenting a valid assay range from 6.55 to 4000 pg/mL.The intra-and inter-run accuracy and precision were within-19.3%to 15.3%and 5.5%to 17.0%,respectively.S3101 was stable in human serum for 280 days at-20℃and-70℃,for 2 h prior to pre-treatment and 24 h post pre-treatment at room temperature(22℃-28℃),respectively,and after five and two freeze-thaw cycles at-70℃and-20oC,respectively.The Simoa assay also demonstrated sufficient dilution linearity,assay sensitivity,and parallelism for quantifying S3101 in human serum.The Simoa assay is a sensitive and adequate method for evaluating the pharmacokinetic parameters of S3101 in human serum.
文摘Two rapid,sensitive and reliable immunoassay methods,namely competitive indirect enzyme-linked immunosorbent assay(CI- ELISA)and colloidal gold-based immunochromatographic assay(CGIA),were developed to detect ofloxacin(OFL).The linear range of the CI-ELISAwas from 0.5 to 128 ng/mL with a limit of detection(LOD)of 0.35 ng/mL.Good recoveries were obtained in analyzing simulated swine urine samples.The CGIA could accurately estimate OFL at concentrations as low as 10 ng/mL in less than 10 min,and test results were read visually without any instrument.
基金supported by the National Basic Research Program of China (973 Program,no. 2007CB714507)National Nature Science Foundation of China (no. 90813015)
文摘A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 2 0.6703;however,the correlation between MPs-CLEIA and ECLIA (R 2 0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R 2 0.6866).
文摘BACKGROUND Current diagnosis of hepatitis C virus(HCV)infection requires two sequential steps:testing for anti-HCV followed by HCV RNA PCR to confirm viremia.We have developed a highly sensitive and specific HCV-antigens enzyme immunoassay(HCV-Ags EIA)for one-step diagnosis of viremic HCV infection.AIM To assess the clinical application of the HCV-Ags EIA in one-step diagnosis of viremic HCV infection in human immunodeficiency virus(HIV)-coinfected individuals.METHODS The study blindly tested HCV-Ags EIA for its performance in one-step diagnosing viremic HCV infection in 147 sera:10 without HCV or HIV infection;54 with viremic HCV monoinfection;38 with viremic HCV/HIV coinfection;and 45 with viremic HCV and non-viremic HIV coinfection.RESULTS Upon decoding,it was 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR test.In five sera with HCV infection,HCV RNA was as low as 50-59 IU/mL,and four out of five tested positive for HCV-Ags EIA.Likewise,it was also 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR in 83 sera with HCV and HIV coinfection,regardless if HIV infection was active or not.CONCLUSION The modified HCV-Ags EIA has a lower detection limit equivalent to serum HCV RNA levels of approximately 100 IU/mL.It is highly sensitive and specific in the setting of HIV coinfection,regardless of HIV infection status and CD4 count.These data support the clinical application of the HCV-Ags EIA in one-step diagnosis of HCV infection in HIV-infected individuals.
基金supported by Pasteur Institute of Iran(funding No 754)Kermanshah University of Medical Sciences(funding No 980467).
文摘Objective:To compare limiting dilution assay and real-time PCR methods in Leishmania tropica parasite load measurement in vaccinated mice.Methods:BALB/c mice were vaccinated by Leishmania tropica soluble Leishmania antigen or recombinant Leishmania tropica stressinducible protein-1 with/without adjuvant.After three vaccinations,mice were challenged by Leishmania tropica promastigotes.Two months after challenge,the draining lymph nodes of mice footpad were removed and parasite load was assayed by limiting dilution assay and real-time PCR methods.Limiting dilution assay was done by diluting tissue samples to extinction in a biphasic medium.For real-time PCR,DNA of the lymph nodes was extracted,equal dilutions of each sample were prepared and hot-start real-time PCR was done using appropriate primers.The data of the two methods were compared by appropriate statistical methods.Results:Both methods were able to measure different levels of parasite load in vaccinated/unvaccinated mice.In addition,wherever parasite load of a group was estimated high(or low)by one method,the estimated parasite load by another method was the same,although statistically significant differences were found between some groups.Conclusions:Both methods lead to approximately similar results in terms of differentiating parasite load of the experimental groups.However,due to the lower errors and faster process,the real-time PCR method is preferred.
文摘Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(F.limonia).Methods:Qualitative phytochemical analysis of extracts,fractions or compound was performed by means of thin layer chromatography and spectroscopic assays.The%purity of compound was measured by analytical HPLC.Extracts,fractions or compound have been individually evaluated for their cytotoxicity effects(10,20,100,250,500,750 and 1 000 μg/mL).Based on the inhibitory concentration(IC_(50)) obtained from the cell viability assay,graded concentrations of extracts,fractions or isolated compound were assessed(10,20,50,100,200 μg/mL) for its hepatoprotective potential against CCl_4-induced hepatotoxicity by monitoring activity levels of serum glutamatic pyruvatic transaminase(SGPT) and serum glutamic oxaloacetic transaminase(SGOT).Results:Results indicated that the methanol extract of F.limonia was non-toxic and hepatoprotective in nature as compared with the petroleum ether extract.The acetone fraction of methanolic extract also showed similar properties but the subsequent two fractions were cytotoxic.However,the pure compound isolated from the penultimate fraction of methanolic extract was non-toxic and hepatoprotective in nature.Biochemical investigations(SCOT,SCPT) further corroborated these cytological observations.Conclusions:It can be concluded from this study that F.limonia methanol extract,some fractions and pure isolated compound herein exhibit hepatoprotective activity.However,cytotoxicity recorded in the penultimate fraction and investigation of structural details of pure compound warrants further study.
文摘INTRODUCTION The hepatitis A virus specific immunoglobulin M(IgM)antibody is a specific serological marker forearly diagnosis of hepatitis A..At present,themethods used at home or abroad for detecting anti-HAV IgM are RIA,ELISA and SPHAI.The dotimmunogold combination assay that has beendeveloped since 1989 is a new technique with theproperty of simple and rapid immunologicaldetection,by using the red colloidal gold particles tolabel the antibodies as indicator,and the
