Acquired drug resistance during the turnaround time for drug susceptibility testing impacts outcome of tuberculosis.

BACKGROUND: The impacts of acquired resistance to first-line drugs other than rifampicin during turnaround time (TAT) for drug susceptibility testing (DST) on tuberculosis (TB) treatment are unclear. METHOD: We performed a prospective cohort study to test acquired resistance to isoniazid, ethambutol and pyrazinamide during TAT for DST as risk factors for prolonged time to sputum culture conversion (SCC) and treatment failure in China. Participants included had a baseline DST result for a Mycobacterium tuberculosis (Mtb) isolate collected at TB diagnosis and a follow-up DST result for a Mtb isolate collected upon baseline DST results availability. Acquired drug resistance was identified by comparing baseline and follow-up DST results. RESULTS: This study included 65 patients with acquired resistance Mtb isolates and 130 patients with consistent drug susceptibility profiles. Cox proportional hazard regression analysis demonstrated acquired isoniazid resistance (aHR 0.50, 95%CI: 0.29-0.85) and acquired pyrazinamide resistance (aHR 0.54, 95%CI: 0.36-0.81) were associated with prolonged time to SCC. Moreover, acquired isoniazid resistance (aOR 7.64, 95%CI: 2.39-16.08) and acquired pyrazinamide resistance (aOR 5.71, 95%CI: 2.31-14.12) were independently associated with treatment failure. CONCLUSION: Acquired resistance to isoniazid and/or pyrazinamide during TAT for DST was associated with prolonged time to SCC as well as treatment failure.

Effects of Cerebellar Transcranial Direct Current Stimulation in Patients with Stroke: a Systematic Review.

BACKGROUND: The cerebellum is involved in regulating motor, affective, and cognitive processes. It is a promising target for transcranial direct current stimulation (tDCS) intervention in stroke. OBJECTIVES: To review the current evidence for cerebellar tDCS (ctDCS) in stroke, its problems, and its future directions. METHODS: We searched the Web of Science, MEDLINE, CINAHL, EMBASE, Cochrane Library, and PubMed databases. Eligible studies were identified after a systematic literature review of the effects of ctDCS in stroke patients. The changes in assessment scale scores and objective indicators after stimulation were reviewed. RESULTS: Eleven studies were included in the systematic review, comprising 169 stroke patients. Current evidence suggests that anode tDCS on the right cerebellar hemisphere does not appear to enhance language processing in stroke patients. Compared with the sham group, stroke patients showed a significant improvement in the verb generation task after cathodal ctDCS stimulation. However, with regard to naming, two studies came to the opposite conclusion. The contralesional anodal ctDCS is expected to improve standing balance but not motor learning in stroke patients. The bipolar bilateral ctDCS protocol to target dentate nuclei (PO10h and PO9h) had a positive effect on standing balance, goal-directed weight shifting, and postural control in stroke patients. CONCLUSIONS: ctDCS appears to improve poststroke language and motor dysfunction (particularly gait). However, the evidence for these results was insufficient, and the quality of the relevant studies was low. ctDCS stimulation parameters and individual factors of participants may affect the therapeutic effect of ctDCS. Researchers need to take a more regulated approach in the future to conduct studies with large sample sizes. Overall, ctDCS remains a promising stroke intervention technique that could be used in the future.

Development of a new rapid, economical and eco-friendly HPLC method for in vitro and in vivo determination of zolmitriptan.

Multiple high-performance liquid chromatographic (HPLC) approaches have been briefly defined for the assessment of zolmitriptan (ZMT). These methods are either cumbersome or require a plentiful volume of organic solvents, thus offering extortionate procedures. The objective of this study was to establish and validate a new rapid, eco- friendly and cost-effective HPLC method for the analysis of ZMT. The calibration curve for ZMT was established using simulated salivary fluid (SSF) and rat plasma for in-vitro and in-vivo analysis, respectively. Chromatogram separation was performed using a CST column (250mm × 4.6mm, 5µm) as a stationary phase and maintained at a temperature of 40°C. The methods were authenticated for linearity, system suitability, accuracy, precision, reproducibility, limit of detection (LOD) and limit of quantification (LOQ). The results of the validation variables and stability studies indicated that the methods were established in accordance with the guidelines of ICH and the USFDA. The established technique was time-saving, precise, eco- friendly and economical compared with the reported technique. In addition, the developed method was sufficiently repeatable for in vitro and in vivo analysis of ZMT.

Drug exposure and susceptibility of second-line drugs correlate with treatment response in patients with multidrug-resistant tuberculosis: a multicentre prospective cohort study in China.

BACKGROUND: Understanding the impact of drug exposure and susceptibility on treatment response of multidrug-resistant tuberculosis (MDR-TB) will help to optimise treatment. This study aimed to investigate the association between drug exposure, susceptibility and response to MDR-TB treatment. METHODS: Drug exposure and susceptibility for second-line drugs were measured for patients with MDR-TB. Multivariate analysis was applied to investigate the impact of drug exposure and susceptibility on sputum culture conversion and treatment outcome. Probability of target attainment was evaluated. Random Forest and CART (Classification and Regression Tree) analysis was used to identify key predictors and their clinical targets among patients on World Health Organization-recommended regimens. RESULTS: Drug exposure and corresponding susceptibility were available for 197 patients with MDR-TB. The probability of target attainment was highly variable, ranging from 0% for ethambutol to 97% for linezolid, while patients with fluoroquinolones above targets had a higher probability of 2-month culture conversion (56.3% versus 28.6%; adjusted OR 2.91, 95% CI 1.42-5.94) and favourable outcome (88.8% versus 68.8%; adjusted OR 2.89, 95% CI 1.16-7.17). Higher exposure values of fluoroquinolones, linezolid and pyrazinamide were associated with earlier sputum culture conversion. CART analysis selected moxifloxacin area under the drug concentration-time curve/minimum inhibitory concentration (AUC0-24h/MIC) of 231 and linezolid AUC0-24h/MIC of 287 as best predictors for 6-month culture conversion in patients receiving identical Group A-based regimens. These associations were confirmed in multivariate analysis. CONCLUSIONS: Our findings indicate that target attainment of TB drugs is associated with response to treatment. The CART-derived thresholds may serve as targets for early dose adjustment in a future randomised controlled study to improve MDR-TB treatment outcome.

Influence Mechanism of Energy Efficiency Label on Consumers' Purchasing Behavior of Energy-Saving Household Appliances.

Mandatory energy efficiency label is an effective way to change consumers' consumption habits and guide them to buy energy-saving appliances. However, few studies concerned about the impact of energy efficiency label on consumers' purchasing behavior. Based on the theory of planned behavior (TPB), social cognitive theory and signaling theory, this paper constructs a theoretical model of the effect of the energy label on consumers' purchasing behavior of energy-saving household appliances. The survey data of 396 household appliance consumers in Mianyang City, China, are collected by the interception method, and the theoretical model is tested by structural equation modeling (SEM). Empirical results of this study indicate that consumers' cognition and perceived value of energy efficiency label significantly affect label trust. Perceived value has a significant impact on consumers' purchasing behavior of energy-saving appliances, while label cognition and label trust indirectly influence consumers' purchasing behavior through the intermediary variable of purchase intention. External environmental factors such as publicity and education as well as subjective norms affect consumers' actual purchasing behavior through the intermediary effect of purchase intention. This study provides important insights into the policy intervention measures to promote consumers' purchasing behavior of energy-saving appliances.

Alterations of gut microbiota in patients with active pulmonary tuberculosis in China: a pilot study.

BACKGROUND: The aim of this study was to identify the differences in diversity, composition, and function of the gut microbiota between tuberculosis (TB) patients and healthy controls (HCs). METHODS: A cross-sectional study was conducted in three cities of China. Stool samples from 94 treatment-naive TB patients and 62 HCs were analyzed by 16S rRNA gene sequencing. TB patients were further divided into antibiotic-free and antibiotic-exposure according to their use of non-specific antibiotics before the TB diagnosis. RESULTS: Compared with HCs, antibiotic-free TB patients presented a different gut microbial community (P < 0.005) and decreased Shannon diversity (P < 0.005). Among TB patients, the relative abundances of short-chain fatty acid (SCFA)-producing genera such as Lachnospiraceae ND3007 group (log2(FC) = -2.74) were lower, while several conditional pathogen-related genera such as Enterococcus (log2(FC) = 12.05) and Rothia (log2(FC) = 6.322) were at higher levels. In addition, 41% of patients received antibiotics before TB diagnosis. Antibiotic exposure was correlated with an additional reduction in α diversity and depletion of SCFA-producing bacteria. Microbial functional analysis revealed that the biosynthesis capacity of amino acids and fatty acids was lower among TB patients compared to HCs. CONCLUSIONS: Significant alterations in gut microbiota composition and metabolic pathways of TB patients were observed. Antibiotic exposure could alter the gut microbiota of TB patients, which should be considered in anti-TB treatment.

Emergence of additional drug resistance during treatment of multidrug-resistant tuberculosis in China: a prospective cohort study.

OBJECTIVES: Little is known about how additional second-line drug resistance emerges during multidrug-resistant tuberculosis (MDR-TB) treatment. The present study aimed to investigate the influence of microevolution, exogenous reinfection and mixed infection on second-line drug resistance during the recommended 2-year MDR-TB treatment. METHODS: Individuals with MDR-TB were enrolled between 2013 and 2016 in a multicentre prospective observational cohort study and were followed up for 2 years until treatment completion. Whole-genome sequencing (WGS) was applied for serial Mycobacterium tuberculosis isolates from study participants throughout the treatment, to study the role of microevolution, exogenous reinfection and mixed infection in the development of second-line drug resistance. RESULTS: Of the 286 enrolled patients with MDR-TB, 63 (22.0%) M. tuberculosis isolates developed additional drug resistance during the MDR-TB treatment, including 5 that fulfilled the criteria of extensively drug-resistant TB. By comparing WGS data of serial isolates retrieved from the patients throughout treatment, 41 (65.1%) of the cases of additional second-line drug resistance were the result of exogenous reinfection, 18 (28.6%) were caused by acquired drug resistance, i.e. microevolution, while the remaining 4 (6.3%) were caused by mixed infections with drug-resistant and drug-susceptible strains. In multivariate analysis, previous TB treatment (adjusted hazard ratio (aHR) 2.51, 95% CI 1.51-4.18), extensive disease on chest X-ray (aHR 3.39, 95% CI 2.03-5.66) and type 2 diabetes mellitus (aHR 4.00, 95% CI 2.22-7.21) were independent risk factors associated with the development of additional second-line drug resistance. CONCLUSIONS: A large proportion of additional second-line drug resistance emerging during MDR-TB treatment was attributed to exogenous reinfection, indicating the urgency of infection control in health facilities as well as the need for repeated drug susceptibility testing throughout MDR-TB treatment.

[Preparation and quality evaluation of orodispersible film containing ginkgolide B novel nanosuspension lyophilized powder].

To prepare a new dosage form that can improve the drug loading of the film--ginkgolide B nanosuspension lyophilized powder orodispersible film(GB-NS-LP-ODF) and to evaluate its quality. Firstly, ginkgolide B nanosuspension(GB-NS) was prepared by media milling method, and then ginkgolide B nanosuspension lyophilized powder(GB-NS-LP) was prepared with freeze-drying method. The mannitol was used as lyoprotectant and its dosage was also investigated. GB-NS-LP-ODF was prepared by solvent casting method and its formulation was screened by single factor test method and optimized by orthogonal test. The appearance, mechanical properties, content uniformity and in vitro dissolution of the optimized GB-NS-LP-ODF were investigated. The particle size of prepared GB-NS was about 201 nm, and the optimal dosage of mannitol was 8%. According to the optimal formula, the GB-NS-LP-ODF was prepared with GB-NS-LP 35.6%, PVA 0588 49.4%, PEG 400 10.7% and CMS-Na 4.3%, and completely disintegrated in about 30 s, and the particle size of reconstituted GB nanoparticles from ODF was about 210 nm. The film with smooth appearance and good mechanical properties was stable within 30 days and the content uniformity(A+2.2 S<15) conformed to the regulations. Scanning electron microscope(SEM) showed that GB-NS-LP-ODFs were evenly distributed and the particle size was about 200 nm. X-rays diffraction(XRD) showed that its crystallinity was significantly lower than that of GB raw drug and GB-ODF. The results of in vitro release test showed that the drug film was completely dissoluted within 10 minutes. These results indicated that nanosuspension lyophilized powder was prepared by freeze drying of nanosuspensions, and then loaded into the orodispersible film to effectively increase the drug loading of the ODF and have broad application prospects.

Longitudinal profiling of gut microbiome among tuberculosis patients under anti-tuberculosis treatment in China: protocol of a prospective cohort study.

BACKGROUND: Anti-tuberculosis therapy requires at least six-month treatment with continuous administration of combined antibiotics, including isoniazid, rifampicin, pyrazinamide, and ethambutol. The long-term exposure to antibiotics could cause consequent changes in gut microbiota, which may alter the gastrointestinal function and drug absorption in patients, thereby affect the outcome of treatment. The study aims to characterize the longitudinal changes of gut microbiota among tuberculosis (TB) patients under standardized first-line treatment and provide an understanding of the association between alterations in gut microbiota composition and unfavorable clinical outcomes. METHODS: The study is a multicenter, observational prospective cohort study. Three study sites are purposively selected in the western (Sichuan Province) and eastern (Jiangsu Province and Shanghai) parts of China. Three-hundred patients with bacteriologically confirmed pulmonary TB are enrolled. All eligible patients should be investigated using structured questionnaires before treatment initiation; and be followed up during the treatment at Day-14, Month-2, Month-5, the end of treatment and the sixth month after ending therapy. Stool samples are to be collected at each visit, consisting of six stool samples from each patient. Additionally, 60 healthy volunteers from Sichuan province and Shanghai city will be recruited as healthy controls to form the baseline of patient gut microbiota in the Chinese population. The dynamic changes of gut microbiota in terms of alpha diversity, beta diversity, taxonomic composition are to be illustrated individually from the time at diagnosis until the sixth month after therapy is completed. Furthermore, the diversity and component of gut microbiota will be compared between the groups with and without unfavorable treatment outcome in terms of adverse effect and treatment failure. DISCUSSION: Studies on the clinical manifestations, adverse reactions, and gut microbiota alterations will provide scientifically-sound evidence on the impact of gut microbiota alterations on TB treatment outcomes. The study is not only useful for guiding personalized TB treatment but also sheds light on the effects of continuous antibiotics administration on gut microbiota. TRIAL REGISTRATION: Chinese Clinical Trial Registry, trial ID: ChiCTR1900023369, May 24, 2019. Retrospectively registered.

Reynoutria Japonica from Traditional Chinese Medicine: A Source of Competitive Adenosine Deaminase Inhibitors for Anticancer.

BACKGROUND: Adenosine deaminase (ADA) is an important enzyme in purine metabolism and is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Traditional Chinese Herbal Medicine (TCHM) is widely used alone or in combination with chemotherapy to treat cancer, due to its ability to deliver a broad variety of bioactive secondary metabolites as promising sources of novel organic natural agents. OBJECTIVE: In the present study, 29 varieties of medicinal plants were screened for the presence of ADA inhibitors. RESULTS: Extracts from Reynoutria japonica, Glycyrrhiza uralensis, Lithospermum erythrorhizon, Magnolia officinalis, Gardenia jasminoides, Stephania tetrandra, Commiphora myrrha, Raphanus sativus and Corydalis yanhusuo demonstrated strong ADA inhibition with rates greater than 50%. However, Reynoutria japonica possessed the highest ADA inhibitory activity at 95.26% and so was used in our study for isolating the ADA inhibitor to be further studied. Eight compounds were obtained and their structures were identified. The compound H1 had strong ADA inhibitory activity and was deduced to be emodin by 1H and 13C-NMR spectroscopic analysis with an IC50 of 0.629 mM. The molecular docking data showed that emodin could bind tightly to the active site of ADA. Our results demonstrated that emodin displayed a new biological activity which is ADA inhibitory activity with high cytotoxic activity against K562 leukemia cells. The bioactivity of cordycepin was significantly increased when used in combination with emodin. CONCLUSION: Emodin may represent a good candidate anti-cancer therapy and adenosine protective agent.

High-risk screening and detection of multidrug-resistant tuberculosis in two prefectures of China: a drug susceptibility surveillance-based secondary data analysis.

BACKGROUND: In China, less than one-fifth of multidrug-resistant tuberculosis (MDR-TB) cases are detected. MDR-TB screening is conducted amongst the following five high-risk groups of TB patients: chronic cases, close contacts of MDR-TB patients, patients with treatment failure, relapsed and returned patients, and smear-positive patients at the end of the third month of initial treatment. OBJECTIVE: To estimate the possibility of detecting MDR-TB cases if only the high-risk screening strategy is applied in China. METHODS: A secondary analysis was applied to the surveillance-based longitudinal data of all sputum smear-positive TB patients in Prefecture E and Prefecture W of China from 2013 to 2015. The population attributable risk (PAR) was estimated using odds ratios for five risk factors/predictors and exposure proportions amongst all MDR-TB cases. RESULTS: A total of 3513 TB patients (2807 from Prefecture E and 706 from Prefecture W) were included. Males accounted for 77.91% (2737/3513) of the patients. The average age was 52.5 ± 20.0 years old. Overall, 40.34% (71/176) of MDR-TB patients were from the five high-risk groups during the three-year study period. The detected proportion of MDR-TB cases using the high-risk screening strategy was significantly higher in Prefecture E than in Prefecture W. The PAR% for all five risk factors/predictors was 43.4% (95% CI: 24.6-61.7%), 49.9% (95% CI: 31.3-67.0%), and 30.3% (95% CI: 12.9-50.1%) in Prefecture E and 36.6% (95% CI: 10.4-64.5%), 13.3% (95% CI: -1.7-39.7%), and -82.5% (95% CI: -117.5--11.2%) in Prefecture W in 2013, 2014, and 2015, respectively. The PAR% for the five specific risk factors/predictors ranged from 0.4% (95% CI: -0.2-4.8%) to 21.0% (95% CI: 13.1-30.0%) in these two prefectures. CONCLUSION: In general, a high-risk screening strategy would miss more than half of the MDR-TB patients because they do not belong to the five high-risk groups.

Multi-center evaluation of GenoType MTBDRsl line probe assay for rapid detection of pre-XDR and XDR Mycobacterium tuberculosis in China.

OBJECTIVES: The implementation of rapid and reliable drug susceptibilities diagnosis is fundamental for effective treatment of multidrug-resistant tuberculosis(MDR-TB). The present study aimed to assess the diagnostic performance of the 2nd-version GenoType MTBDRsl kit as well as the impact of its implementation on the turnaround time in a multi-center Chinese study. METHODS: Totally 353 MDR-TB patient specimens were consecutively tested. The 2nd-version GenoType MTBDRsl assay, drug susceptibility testing with the MGIT 960 system, and sequencing were performed and compared. RESULTS: MTBDRsl testing identified the major genotypes associated with fluoroquinolones resistance, predominated by gyrA MUT3B (Asp94Asn and Asp94Tyr, 26.5%) and MUT3C (Asp94Gly, 19.5%). The genotypes associated with resistance to 2nd-line injectable drugs(SLIDs) were rrsMUT1(A1401G, 64.9%) and absence of WT1(C1402T, 10.5%). The sensitivities for detection of resistance to fluoroquinolones, SLIDs, and their combination (extensively drug resistance, XDR) were 80.5%, 80.7% and 73.5% and specificities were 100.0%, 99.3% and 99.1%, respectively. Implementation of this test significantly reduced the turnaround time between sample collection and result reporting from 45 to 3 days, a reduction by 93.3% (p, 0.001). CONCLUSION: With a favorable diagnostic performance and short turnaround time, the 2nd-version GenoType MTBDRsl assay proves its value for early diagnosis of resistance to 2nd-line drugs as well as of XDR-TB in China.

pncA mutations are associated with slower sputum conversion during standard treatment of multidrug-resistant tuberculosis.

Despite the strong association between drug resistance and genetic mutations, the value of molecular diagnosis of drug resistance to guide the treatment of multidrug-resistant tuberculosis (MDR-TB) remains unclear. This is particularly relevant in resource-limited areas where it is difficult to perform drug susceptibility testing (DST). Here we investigated the association between drug susceptibility phenotypes and genotypes and treatment outcomes in patients with MDR-TB. This study enrolled 74 consecutive patients with confirmed MDR-TB between 2010 and 2011, and outcomes were followed-up over the 24-month treatment course. All of the isolates were tested for phenotypic susceptibility to second-line drugs using the Mycobacteria Growth Indicator Tube (MGIT)-based system, and genotypic mutations were assessed by DNA sequencing. Among the 74 MDR-TB isolates, 29 (39.2%) were resistant to fluoroquinolones and/or second-line injectable drugs, of which 21 (72.4%) harboured a mutation in drug resistance-related genes (gyrA, rrs or eis). In addition, 32 individuals (43.2%) also had pyrazinamide (PZA)-resistant isolates, with 28 (87.5%) containing the pncA mutation. By backward selection in the multivariate logistic regression and Cox proportional hazard models, PZA resistance and its related pncA gene mutation demonstrated a correlation with a lower likelihood of culture conversion at 8 weeks and treatment success. Meanwhile, the fluoroquinolone resistance-related gyrA gene mutation was negatively correlated with treatment success. DST for PZA and fluoroquinolones together with genetic information appears to provide a clinically useful indicator of the treatment outcome of MDR-TB in China.

Impact of genotypic and phenotypic resistance to second-line anti-tuberculosis drugs on treatment outcomes in multidrug-resistant tuberculosis in China.

BACKGROUND: Despite the strong association between drug resistance and genetic mutations, the value of molecular diagnosis of drug resistance to guide the treatment of multidrug-resistant tuberculosis (MDR-TB) remains unclear. This is particularly relevant in resource-limited areas, in which it is difficult to implement the drug susceptibility test. Here, we focused on the association of drug susceptibility phenotype and genotype with treatment outcomes in patients with MDR-TB. METHODS: In a prospective cohort study, we enrolled 252 consecutive patients with confirmed MDR-TB between 2010 and 2013, and outcomes were followed-up over the 24-month treatment course in terms of clinical manifestation and sputum conversion. All the isolates were tested for phenotypic susceptibility to second-line drugs in the Mycobacteria Growth Indicator Tube based system, and genotypic mutations were assessed by DNA sequencing. RESULTS: Among the 252 MDR-TB isolates, 88 (34.9%) were resistant to fluoroquinolones and/or second-line injectable drugs, of which 65 (73.9%) harbored a mutation in drug resistance-related genes (gyrA, rrs and eis). In addition, 85 individuals (33.7%) were also resistant to pyrazinamide, with 87.1% containing the pncA mutation. Of 252 MDR-TB patients, 207 (82.1%) had known outcomes and 45 (17.9%) were lost to follow-up. Among those with known outcomes, treatment succeeded in 85.8% with plain MDR-TB, 69.7% with initial resistance to either a fluoroquinolone or second-line injective drugs, 37.5% with initial resistance to pyrazinamide, 29.3% with initial extensively drug resistance. In contrast, among those with known outcomes, treatment success and culture conversion depends on the susceptibility to drug especially for pyrazinamide and fluoroquinolones. In multivariate analysis, pyrazinamide resistance and its related pncA gene mutation were independently associated with a lower risk of culture conversion on at 8weeks and treatment success, while fluoroquinolone resistance was negatively correlated with treatment success. Besides, specific treatment, patient and program variables were also associated with treatment outcome. CONCLUSION: Drug susceptibility testing for pyrazinamide and fluoroquinolones together with genetic information appears to provide a clinically useful indicator of the treatment outcome of MDR-TB in China.

Influence of miR-30b regulating humoral immune response by genetic difference.

Investigation of genetic difference will be beneficial to researchers to understand the origins and nature of diseases. Previous studies have revealed that L-kynurenine (L-Kyn) level was changed significantly in patient with cancer and that miR-30b play different role in tumor cells and immune cells. Moreover, it has been also conformed that miR-30b involved in the process of L-Kyn-mediated suppression of humoral immune responses induced by lipopolysaccharide (LPS) in human normal B cells separated from volunteers' peripheral blood. Nevertheless, the miR-30b role regulating humoral immune response in B lymphoma cells has been still unclear due to the genetic difference between normal cells and tumor cells. The current study demonstrated that the selected concentration of L-Kyn (100, 1000 µM) significantly reduced the immunoglobulin M secretion induced by LPS when compared with the control group in B lymphoma, CH12.LX, and BCL-1 cells, which had, at least, incomplete dependence on Aryl hydrocarbon receptor, the receptor of L-Kyn. In addition, although L-Kyn (100 µM) significantly attenuated the expression of miR-30b in BCL-1 cells rather than in CH12.LX cells, no significant differences in the strength of L-Kyn-mediated suppression of humoral immune responses induced by LPS were detected by enzyme-linked immunosorbent assay between the LPS (10 µg/ml) + L-Kyn (100 µM) group and the LPS (10 µg/ml) + L-Kyn (100 µM) + miR-30b mimics/miR-30b inhibitor group in CH12.LX and BCL-1 cells, respectively. Further data also showed that mouse Bach2 mRNA was a novel target of miR-30b. These results suggest that genetic difference among cells has a great influence on the miR-30b role in the process of L-Kyn-mediated suppression of humoral immune responses induced by LPS.

Full-length genome of wild-type hepatitis A virus (DL3) isolated in China.

AIM: To characterize the genome of an wild-type HAV isolate (DL3) in China. METHODS: A stool specimen was collected from hepatitis A patient from Dalian, China. HAV (DL3) was isolated and viral RNA was extracted. The genome of DL3 was amplified by reverse transcription and polymerase chain reaction (RT-PCR), followed by cloning into pGEM-T vector. The positive colonies were selected and sequenced. The full-length genome of DL3 was analyzed and compared with other wild-type HAV isolates. RESULTS: The genome of DL3 was 7 476 nucleotides (nt) in size, containing 732-nt 5'untranslated region (UTR), 6 681-nt open reading frame (ORF) which encoded a polyprotein of 2 227 amino acids (aa), and 63-nt 3'UTR. The base composition was 28.96 % A (2 165), 16.08 % C (1 202), 22.11 % G(1 653) and 32.85% U (2 456). Genomic comparisons with wild-type HAV isolates revealed that DL3 had the highest identity of 97.5 % for nt (185 differences) with AH1, the lowest identity of 85.7 % (1 066 differences) with SLF88. The highest identity of 99.2 % for amino acid (18 differences) appeared among DL3, AH2 and FH3, and the lowest identity of 96.8 % (72 differences) between DL3 and SLF88. Based upon comparisons of the VP1/2A junction and the VP1 amino terminus, DL3 was classified as subgenotype IA. Phylogenetic analysis showed that DL3 was closest to the isolates in Japan. CONCLUSION: The sequence comparison and phylogenetic analysis revealed that DL3 is most similar to the isolates in Japan, suggesting the epidemiological link of hepatitis A happened in China and Japan.

Mutational characteristics in consecutive passage of rapidly replicating variants of hepatitis A virus strain H2 during cell culture adaptation.

AIM: To investigate the molecular mechanism of cell adaptation and rapid replication of hepatitis A virus strain H2 in KBM17 cells. METHODS: Virus of strain H2 at passage 7 was consecutively passaged in KBM17 cells for 22 passages, every passage was incubated for 14 days. Antigenic and infectious titers of every passage and one-step growth dynamics of passage 22 were determined with ELISA. Genomes of passage 6, passage 12, passage 18 and passage 22 were sequenced and compared with H2K7. RESULTS: During continuous passage of vaccine strain H2 at passage K7 in KMB17 cells, infectious and antigenic titers increased with the increase of passages, infectious titers at day 14 reached 6.77LgCCID(50)ml(-1) for passage 6 (P6), 7.0 LgCCID(50)ml(-1) for passage 12 (P12), 7.33 LgCCID(50)ml(-1) for passage 18 (P18) and 7.83 LgCCID(50)ml(-1) for passage 22 (P22), respectively. The one-step growth dynamics showed that replicating peak of P22 appeared at day 14 with infectious titers of 7.83 LgCCID(50)ml(-1) and antigenic titer of 1:1024. After passage 22 a new cell-adapted variant (P22) of H2K7 with rapid and shortened replication cycle from 28 days to 14 days was obtained. Sequencing and comparisons of genomes of P6, P12, P18 and P22 showed that mutational numbers in genomes of different passages increased with adaptive passages, and mutations scattered over the genome. In comparison with that of K7, P6 had only 6 nucleotides (nt) mutations, P12 had 7 mutational changes, in addition to 6 same mutations with P6, there appeared a new mutation in 5'NTR at nucleotide position 591 resulting in a nucleotide exchange from A to G. P18 had 10 nt mutations, among the 10 mutations, 7 mutational changes were same as with P12, three new mutational changes appeared in the genome, one in 5'NTR, one in 3C coding region, one in 3D coding region, at P22 there appeared 18 nucleotide changes in the genome, on the basis of P18,there occurred additional 8 nucleotide mutations, two in 5'NTR, three in 2C, one in 3A, one in 3C and one in 3D. The results suggested that although H2K7 was already an attenuated strain, the mutations of genome is not sufficient to completely adapt the KMB17, further mutations caused rapid replication adaptation. CONCLUSION: 18-nt changes scattering over the genome are cooperatively responsible for further adaptation characterized by rapid and shortened replication cycle from 28 days to 14 days in KMB17 cells. The mutations in 2C coding region play more important role in increase of infectious titer than other mutations, the mutations in 2B coding region show less important role than it usually does in cell adaptation, nucleotide changes in 5' NTR seem to be not relevant to cell adaptation during initial stages (before P6), but do in late stages.