Hepatitis B virus(HBV)reactivation(HBVr)represents a severe and potentially life-threatening condition,and preventive measures are available through blood test screening or prophylactic therapy administration.The asse...Hepatitis B virus(HBV)reactivation(HBVr)represents a severe and potentially life-threatening condition,and preventive measures are available through blood test screening or prophylactic therapy administration.The assessment of HBVr traditionally considers factors such as HBV profile,including hepatitis B surface antigen(HBsAg)and antibody to hepatitis B core antigen,along with type of medication(chemotherapy;immunomodulants).Nevertheless,consideration of possible patient’s underlying tumor and the specific malignancy type(solid or hematologic)plays a crucial role and needs to be assessed for decision-making process.展开更多
Hyperuricemia is a metabolic disorder caused by abnormal purine metabolism,resulting in abnormally high serum uric acid.In this study,a novel Levilactobacillus brevis PDD-5 isolated from salty vegetables was verified ...Hyperuricemia is a metabolic disorder caused by abnormal purine metabolism,resulting in abnormally high serum uric acid.In this study,a novel Levilactobacillus brevis PDD-5 isolated from salty vegetables was verified with the function of alleviating hyperuricemia.The relevant effects of L.brevis PDD-5 in lowering uric acid were analyzed by in vitro and in vivo experiments.The results showed that the L.brevis PDD-5 has(68.86±15.46)%of inosine uptake capacity and(95.75±3.30)%of guanosine uptake capacity in vitro.Oral administration of L.brevis PDD-5 to hyperuricemia rats reduced uric acid,creatinine,and urea nitrogen in serum,as well as decreased inosine and guanosine levels in the intestinal contents of rats.Analysis of relevant markers in the kidney by ELISA kits revealed that L.brevis PDD-5 alleviated oxidative stress and inflammation.Moreover,the gene expression of uric acid transporter 1(URAT1)and glucose transporter 9(GLUT9)was down-regulated,and the gene expression of organic anion transporter 1(OAT1)was up-regulated after treatment with L.brevis PDD-5.Western blot analysis showed that L.brevis PDD-5 alleviated hyperuricemia-induced kidney injury through the NLRP3 pathway.The se findings suggest that L.brevis PDD-5 can lower uric acid,repair kidney damage,and also has the potential to prevent uric acid nephropathy.展开更多
This editorial commented on an article in the World Journal of Gastroenterology titled“Risks of Reactivation of Hepatitis B Virus in Oncological Patients Using Tyrosine Kinase-Inhibitors:Case Report and Literature An...This editorial commented on an article in the World Journal of Gastroenterology titled“Risks of Reactivation of Hepatitis B Virus in Oncological Patients Using Tyrosine Kinase-Inhibitors:Case Report and Literature Analysis”by Colapietro et al.In this editorial,we focused on providing a more comprehensive exploration of hepatitis B virus reactivation(HBVr)associated with the usage of tyrosine kinase inhibitors(TKIs).It includes insights into the mechanisms underlying HBV reactivation,the temporal relationship between TKIs and HBV reactivation,and preventive measures.The aim is to understand the need for nucleos(t)ide analogs(NAT)and serial blood tests for early recognition of reactivation and acute liver injury,along with management strategies.TKIs are considered to be an intermediate(1%-10%)of HBVr.Current guidelines stipulate that patients receiving therapy with high or moderate risks of reactivation or recent cancer diagnosis must have at least tested hepatitis B surface antigen,anti-hepatitis B core antigen(HBc),and anti-hepatitis B surface antibody.Anti-HBc screening in highly endemic areas means people with negative tests should be vaccinated against HBV.Nucleoside or nucleotide analogs(NAs)like entecavir(ETV),tenofovir disoproxil fumarate(TDF),and tenofovir alafenamide(TAF)form the basis of HBV reactivation prophylaxis and treatment during immunosuppression.Conversely,lamivudine,telbivudine,and adefovir are generally discouraged due to their reduced antiviral efficacy and higher risk of fostering drug-resistant viral strains.However,these less effective NAs may still be utilized in cases where ETV,TDF,and TAF are not feasible treatment options.展开更多
Aim: To compare the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia, and to study the effect of humidity and heat on the content of nucleosides. Methods: The contents of nucleos...Aim: To compare the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia, and to study the effect of humidity and heat on the content of nucleosides. Methods: The contents of nucleosides were determined by using high performance capillary electrophoresis (HPCE). Beckman P/ACE System 5010 apparatus equipped with a UV detector and a Beckman untreated fused-silica capillary (57 cm 75 mm, 50 cm effective length) was used. Before sample injection, the capillary was rinsed with 1 molL-1 sodium hydroxide solution and running buffer for 5 min, respectively. A voltage of 20 kV was applied for the separation. Pressure injection was 586 kPa for 6 seconds, and the wavelength of detector was 254 nm. The running time was 20 min at 20 oC. The effect of humidity and heat on the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia was observed for 1, 3, 5 and 10 days at temperature 40 oC, and relative humidity 75%. Results: The content of nucleosides from natural Cordyceps sinensis was higher than that from cultured Cordyceps mycelia. But the contents of nucleosides from freshly collected natural Cordyceps sinensis were very low, even below the limit of quantitation. The contents of nucleosides from natural Cordyceps sinensis were significantly increased by humidity and heat, but this phenomenon was not observed in cultured Cordyceps mycelia. Conclusion: There are differences between the nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia. The nucleosides in natural Cordyceps sinensis may be derived from the degradation of nucleic acids. This implies that adenosine being used for the quality control of natural Cordyceps sinensis may have to be reconsidered.展开更多
For investigating the biological function of ADPR, four novel analogues (compounds 2-5) in which the pyrophosphate linkage was replaced by the aspartic acid dipeptide were synthesized. 5'-Amino adenosine or its ana...For investigating the biological function of ADPR, four novel analogues (compounds 2-5) in which the pyrophosphate linkage was replaced by the aspartic acid dipeptide were synthesized. 5'-Amino adenosine or its analogues was used as the starting material, liquid phase peptide synthesis strategy was used to construct these ADPR analogues. The structures were characterized by 1H NMR and HRMS spectra. This study provides a versatile synthesis of peptide modified ADPR analogues and helps to understand the structure-activity relationship of ADPR.展开更多
Aim To quantitatively determine five nucleosides and nucleobases, including cytidine, uridine, guanosine, adenosine and uracil in different parts of Panax notoginseng. Methods Separation was performed on a Zorbax SB-A...Aim To quantitatively determine five nucleosides and nucleobases, including cytidine, uridine, guanosine, adenosine and uracil in different parts of Panax notoginseng. Methods Separation was performed on a Zorbax SB-Aq column using a gradient elution with mobile phase of 8 mmol^L-1 ammonium acetate aqueous solution (A) and methanol (B). The assay was carried out at a flow rate of 1 mL·min^-1 at 25 ℃ with the diode-array detection at 260 nm. Results Cytidine, uridine, guanosine, adenosine and uracil had good linearity in the ranges of 1.79 - 57.40 μg·mL^-1 (r^2 = 1.0000), 3.30 - 105.60 μg·mL^-1 (r^2 = 1.0000), 3.09 - 98.80 μg·mL^ -1(r^2 = 0.9999), 2.77 - 88.60 μg·mL^-1 (r^2 = 1.0000) and 0.38 - 12.30 μg·mL ^-1 (r^2 = 1.0000) with average recoveries of 93.9%, 96.5%, 92.7%, 93.2% and 98.8%, respectively. The content of cytidine, uridine, guanosine, adenosine and uracil in different parts of P. notogingeng were significantly different. Conclusion This is the first report on quantitative determination of nucleosides and nucleobases in P notoginseng.展开更多
AIM: To evaluate the clinical outcomes of 240-wk treatment with entecavir(0.5 mg) in Chinese nucleosidenaive patients with cirrhosis.METHODS: A total of 204 nucleoside-naive patients with compensated(n = 96) or decomp...AIM: To evaluate the clinical outcomes of 240-wk treatment with entecavir(0.5 mg) in Chinese nucleosidenaive patients with cirrhosis.METHODS: A total of 204 nucleoside-naive patients with compensated(n = 96) or decompensated(n = 108) hepatitis B virus(HBV)-induced cirrhosis at the Department of Gastroenterology of the China-Japan Union Hospital(Jilin University, Changchun, China) who were treated with entecavir(0.5 mg) for 240 wk were enrolled in this study. Liver biopsy samples obtained from 38 patients prior to treatment(baseline) and at week 240 were evaluated by different independent histopathologists. Efficacy assessments included the proportions of patients who achieved an HBV DNA level < 500 copies/m L, the association of interleukin-28 B genetic variation with antivirus therapy, clinical outcomes, and histologic improvement. Changes in liver disease severity were analyzed, and liver histologic evaluation was performed in 38 patients with paired biopsies. Student t tests were used to compare the means of continuous variables between the groups, and the proportions of patients who achieved the endpoints were compared using the χ2 test.RESULTS: At week 240, 87.5% of the patients with compensated cirrhosis and 92.6% of the patients with decompensated cirrhosis achieved a HBV DNA level < 500 copies/m L. Three patients had genotypic entecavir resistance within the 240-wk period. No significant association was observed between virologic response and interleukin-28 genotype(CT, 88.2% vs CC, 90.6%). The proportion of patients with Child-Pughclass A disease was significantly increased at week 240(68%) from the baseline(47%; P < 0.01). The proportion of patients with Child-Pugh class B disease was significantly decreased at week 240(25%) from the baseline(39%; P = 0.02). In the patients with paired liver biopsies, the mean reduction in the Knodell necroinflammatory score from the baseline was 3.58 ± 1.03 points(7.11 ± 1.80 vs 3.53 ± 1.35, P < 0.01). The mean reduction in Ishak fibrosis score from the baseline was 1.26 ± 0.64 points(5.58 ± 0.50 vs 4.32 ± 0.81, P < 0.01).CONCLUSION: Entecavir is an effective treatment option for patients with HBV-related compensated or decompensated cirrhosis that can result in sustained virologic suppression and histologic improvement.展开更多
Hepatitis B virus (HBV) infection is still the most common cause of hepatocellular carcinoma and liver drrhosis world wide. Recently, however, there has been quite dramatic improvement in the understanding of HBV as...Hepatitis B virus (HBV) infection is still the most common cause of hepatocellular carcinoma and liver drrhosis world wide. Recently, however, there has been quite dramatic improvement in the understanding of HBV assodated liver disease and its treatment. It has become dear that high viral replication is a major risk factor for the development of both cirrhosis and hepatocellular carcinoma. Early studies have shown lamivudine lowers the risk of HBV associated complications. There are currently three nucleos(t)ides licensed, in addition to interferon, and there are more drugs coming to the market soon. Interferon or its pegylated counterpart are still the only options for treatment with defined end points, while nudeos(t)ides therapy is used mostly for long term treatment. Combination therapies have not been shown to be superior to monotherapy in naive patients, however, the outcome depends on how the end point is defined. Interferon plus lamivudine achieves a higher viral suppression than either treatment alone, even though Hbe-seroconversion was not different after a one year treatment. HBV-genotypes emerge as relevant factors, with genotypes "A" and "B" responding relatively well to interferon, achieving up to 20% HBsAg clearance in the case of genotype "A". In addition to having a defined treatment duration, interferon has the advantage of lack- ing resistance selection, which is a major drawback for lamivudine and the other nucleos(t)ides. The emergence of resistance against adefovir and entecavir is some- what slower in na'fve compared to lamivudine resistant patients. Adefovir has a low resistance profile with 3%, 9%, 18%, and 28% after 2, 3, 4, and 5 years, respectively, while entecavir has rarely produced resistance in naive patients for up to 3 years.展开更多
AIM:To investigate the effect of antiviral therapy with nucleoside analogs in hepatitis B virus(HBV)-related cirrhosis and esophageal varices.METHODS:Eligible patients with HBV-related cirrhosis and esophageal varices...AIM:To investigate the effect of antiviral therapy with nucleoside analogs in hepatitis B virus(HBV)-related cirrhosis and esophageal varices.METHODS:Eligible patients with HBV-related cirrhosis and esophageal varices who consulted two tertiary hospitals in Beijing,China,the Chinese Second Artillery General Hospital and Chinese PLA General Hospital,were enrolled in the study from January 2005 to December 2009. Of 117 patients,79 received treatment with different nucleoside analogs and 38 served as controls. Bleeding rate,change in variceal grade and non-bleeding duration were analyzed. Multivariate Cox proportional hazard regression was used to identify factors related to esophageal variceal bleeding.antiviral group compared to the control group(29.1%vs 65.8%,P < 0.001). Antiviral therapy was an independent factor related to esophageal bleeding in multivariate analysis(HR = 11.3,P < 0.001). The mean increase in variceal grade per year was lower in the antiviral group(1.0 ± 1.3 vs 1.7 ± 1.2,P = 0.003). Nonbleeding duration in the antiviral group was prolonged in the Kaplan-Meier model. Viral load rebound was observed in 3 cases in the lamivudine group and in 1 case in the adefovir group,all of whom experienced bleeding. Entecavir and adefovir resulted in lower bleeding rates(17.2% and 28.6%,respectively) than the control(P < 0.001 and P = 0.006,respectively),whereas lamivudine(53.3%) did not(P = 0.531).CONCLUSION:Antiviral therapy delays the progression of esophageal varices and reduces bleeding risk in HBV-related cirrhosis,however,high-resistance agents tend to be ineffective for long-term treatment.展开更多
AIM:To investigate the survival rates and prognostic factors in patients with hepatitis B virus-related acuteon-chronic liver failure(HBV-ACLF).METHODS:Clinical data in hospitalized patients with HBV-ACLF admitted fro...AIM:To investigate the survival rates and prognostic factors in patients with hepatitis B virus-related acuteon-chronic liver failure(HBV-ACLF).METHODS:Clinical data in hospitalized patients with HBV-ACLF admitted from 2006 to 2009 were retrospectively analyzed.Their general conditions and survival were analyzed by survival analysis and Cox regression analysis.RESULTS:A total of 190 patients were included in this study.The overall 1-year survival rate was 57.6%.Patients not treated with antiviral drugs had a significantly higher mortality[relative risk(RR)=0.609,P=0.014].The highest risk of death in patients with ACLF was associated with hepatorenal syndrome(HRS)(RR=2.084,P=0.026),while other significant factors were electrolyte disturbances(RR=2.062,P=0.010),and hepatic encephalopathy(HE)(RR=1.879,P<0.001).CONCLUSION:Antiviral therapy has a strong effect on the prognosis of the patients with HBV-ACLF by improving their 1-year survival rate.HRS,electrolyte disturbances,and HE also affect patient survival.展开更多
Three hundred and fifty million people worldwide are estimated to be chronically infected with hepatitis B virus. 15%-40% of these subjects will develop cirrhosis, liver failure or hepatocellular carcinoma during thei...Three hundred and fifty million people worldwide are estimated to be chronically infected with hepatitis B virus. 15%-40% of these subjects will develop cirrhosis, liver failure or hepatocellular carcinoma during their life. The treatment of chronic hepatitis B has improved dramatically over the last decade merits to the advent of nucleoside/nucleotide analogues and the use of pegylated interferons. Approved drugs for chronic hepatitis B treatment include: standard interferon- alpha 2b, pegylated interferon-alpha 2a, lamivudine, adefovir dipivoxil, and entecavir. Unfortunately, these agents are not effective in all patients and are associated with distinct side effects. Interferons have numerous side effects and nucleoside or nucleotide analogues, which are well tolerated, need to be used for prolonged periods, even indefinitely. However, prolonged treatment with nucleoside or nucleotide analogues is associated with a high rate of resistance. Telbivudine is a novel, orally administered nucleoside analogue for use in the treatment of chronic hepatitis B. In contrast to other nucleoside analogues, Telbivudine has not been associated with inhibition of mammalian DNA polymerase with mitochondrial toxicity. Telbivudine has demonstrated potent activity against hepatitis B with a significantly higher rate of response and superior viral suppression compared with lamivudine, the standard treatment. Telbivudine has been generally well tolerated, with a low adverse effect profile, and at its effective dose, no dose- limiting toxicity has been observed. Telbivudine is one of the most potent antiviral agents for chronic hepatitis B virus and was approved by the FDA in late 2006.展开更多
AIM: To analyze the clinical features and risk factors of adverse reactions associated with telbivudine. METHODS: Clinical data were collected from cases that presented with serious adverse reactions to telbivudine. W...AIM: To analyze the clinical features and risk factors of adverse reactions associated with telbivudine. METHODS: Clinical data were collected from cases that presented with serious adverse reactions to telbivudine. We analyzed general information and medicine status, clinical features, results of examination, and misdiagnosis. RESULTS: Out of 105 patients who were treated with telbivudine for hepatitis B in an outpatient department from January, 2007 to January, 2008, five presented with serious adverse drug reactions. Most of these five patients had used other nucleoside analogues in the past. Four were treated with a combination of telbivudine and interferon or another nucleoside analogue, while the other received an increased dose of telbivudine. The main adverse reactions were myalgia and general weakness. This was accompanied by cardiac arrhythmia in one patient, and nervous symptoms in three. Serum creatine kinase was elevated. The rate of misdiagnosis was high. CONCLUSION: The adverse reactions were related to telbivudine, but the biological mechanism of the reactions is not yet clear. Combination therapy with interferon or another nucleoside analogue and a high dose may increase the risk of adverse reactions.展开更多
Hepatitis B virus(HBV)infection is a leading cause of chronic hepatitis,liver cirrhosis,and hepatocellular carcinoma worldwide.Due to the shared modes of transmission,coinfection with HBV and human immunodeficiency vi...Hepatitis B virus(HBV)infection is a leading cause of chronic hepatitis,liver cirrhosis,and hepatocellular carcinoma worldwide.Due to the shared modes of transmission,coinfection with HBV and human immunodeficiency virus(HIV)is not uncommon.It is estimatedthat 10%of HIV-infected patients worldwide are coinfected with HBV.In areas where an HBV vaccination program is implemented,the HBV seroprevalence has declined significantly.In HIV/HBV-coinfected patients,HBV coinfection accelerates immunologic and clinical progression of HIV infection and increases the risk of hepatotoxicity when combination antiretroviral therapy(cART)is initiated,while HIV infection increases the risk of hepatitis events,cirrhosis,and end-stage liver disease related to chronic HBV infection.With the advances in antiviral therapy,concurrent,successful longterm suppression of HIV and HBV replication can be achieved in the cART era.To reduce the disease burden of HBV infection among HIV-infected patients,adoption of safe sex practices,avoidance of sharing needles and diluent,HBV vaccination and use of cART containing tenofovir disoproxil fumarate plus emtricitabine or lamivudine are the most effective approaches.However,due to HIV-related immunosuppression,using increased doses of HBV vaccine and novel approaches to HBV vaccination are needed to improve the immunogenicity of HBV vaccine among HIV-infected patients.展开更多
Herpes simplex virus (HSV), a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir (ACV) and related nucleos...Herpes simplex virus (HSV), a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir (ACV) and related nucleoside analogues can successfully treat HSV infections, but the emergence of drug resistance to ACV has created a barrier for the treatment of HSV infections, especially in immunocompromised patients. There is an urgent need to explore new and effective tactics to circumvent drug resistance to HSV. This review summarises the current strategies in the development of new targets (the DNA helicase/primase (H/P) complex), new types of molecules (nature products) and new antiviral mechanisms (lethal mutagenesis of Janus-type nucleosides) to fight the drug resistance of HSV.展开更多
Chronic hepatitis B virus infection affects about 400 million people around the globe and causes approximately a million deaths a year. Since the discovery of interferon-α as a therapeutic option the treatment of hep...Chronic hepatitis B virus infection affects about 400 million people around the globe and causes approximately a million deaths a year. Since the discovery of interferon-α as a therapeutic option the treatment of hepatitis B has evolved fast and management has become increasingly complicated. The amount of viral replication reflected in the viral load (HBV-DNA) plays an important role in the development of cirrhosis and hepatocellular carcinoma. The current treatment modalities for chronic hepatitis B are immunomodulatory (interferons) and antiviral suppressants (nucleoside and nucleotide analogues) all with their own advantages and limitations. An overview of the treatment efficacy for both immunomodulatory as antiviral compounds is provided in order to provide the clinician insight into the factors influencing treatment outcome. With nucleoside or nucleotide analogues suppression of viral replication by 5-7 log10 is feasible, but not all patients respond to therapy. Known factors influencing treatment outcome are viral load, ALT levels and compliance. Many other factors which might influence treatment are scarcely investigated. Identifying the factors associated with response might result in stopping rules, so treatment could be adapted in an early stage to provide adequate treatment and avoid the development of resistance. The efficacy of compounds for the treatment of mutant virus and the cross-resistance is largely unknown. However, genotypic and phenotypic testing as well as small clinical trials provided some data on efficacy in this population. Discontinuation of nucleoside or nucleotide analogues frequently results in viral relapse; however, some patients have a sustained response. Data on the risk factors for relapse are necessary in order to determine when treatment can be discontinued safely. In conclusion: chronic hepatitis B has become a treatable disease; however, much research is needed to tailor therapy to an individual patient, to predict the sustainability of response and determine the best treatment for those failing treatment.展开更多
The ultimate goals of treating chronic hepatitis B(CHB)is prevention of hepatocellular carcinoma(HCC)and hepatic decompensation.Since the advent of effective antiviral drugs that appeared during the past two decades,c...The ultimate goals of treating chronic hepatitis B(CHB)is prevention of hepatocellular carcinoma(HCC)and hepatic decompensation.Since the advent of effective antiviral drugs that appeared during the past two decades,considerable advances have been made not only in controlling hepatitis B virus(HBV)infection,but also in preventing and reducing the incidence of liver cirrhosis and HCC.Furthermore,several recent studies have suggested the possibility of reducing the incidence of recurrent or new HCC in patients even after they have developed HCC.Currently,six medications are available for HBV treatment including,interferon and five nucleoside/nucleotide analogues.In this review,we will examine the antiviral drugs and the progresses that have been made with antiviral treatments in the field of CHB.展开更多
All oral nucleoside analogues against hepatitis B virus,with an exception of telbivudine,have been reported causing lactic acidosis(LA).Here we report the first case of chronic hepatitis B developing severe refractory...All oral nucleoside analogues against hepatitis B virus,with an exception of telbivudine,have been reported causing lactic acidosis(LA).Here we report the first case of chronic hepatitis B developing severe refractory LA during telbivudine monotherapy.A 36-year-old man of Chinese origin received telbivudine antiviral treatment for chronic hepatitis B.After 11 mo of therapy,he developed anorexia,nausea,and vomiting with mild muscle weakness.The patient was found with elevated serum creatine phosphokinase up to 3683 U/L(upper limit of normal 170 U/L)and marked LA.LA did not resolve immediately following discontinuation of telbivudine.His condition began to improve after hemodialysis treatment for 16 times and usage of glucocorticosteroid.The patient fully recovered after 16 wk of treatment.This is the first documented case with severe LA caused by telbivudine monotherapy.Besides serum creatine phosphokinase,blood lactate level should also be closely monitored in patients receiving telbivudine.展开更多
Previous studies have shown that Arabidopsis equilibrative nucleoside transporters (AtENTs) possess transport activities when produced in yeast cells and are differentially expressed in Arabidopsis organs. Herein, w...Previous studies have shown that Arabidopsis equilibrative nucleoside transporters (AtENTs) possess transport activities when produced in yeast cells and are differentially expressed in Arabidopsis organs. Herein, we report further analysis on the nucleoside transport activities and transcriptional patterns of AtENT members. The recombinant proteins of AtENTs 3, 6, and 7, but not those of AtENTs 1, 2, 4, and 8, were found to transport thymidine with high affinity. Contrary to previ- ous suggestion that AtENT 1 may not transport uridine, this work showed that recombinant AtENT 1 was a pH-dependent and high-affinity transporter of uridine. When grown on MS plates, the AtENT3 knockout plants were more tolerant to the cytotoxic uridine analog 5-fluorouridine than wild-type plants and the knockout plants ofAtENT 1 or AtENT6. Con- sistent with this observation, the AtENT3 knockout line exhibited a significantly decreased ability to take up [^3H]uridine via the roots when compared with wild-type plants and the plants with mutated AtENT 1 or AtENT6. This indicates that AtENT3, but not AtENTs 1 and 6, is the main transporter for uridine uptake in Arabidopsis roots. The transcription of AtENTs 1, 3, 4, 6, 7, and 8 was regulated in a complex manner during leaf development and senescence. In contrast, the six AtENT members were coordinately induced during seed germination. This work provides new information on the transport properties of recombinant AtENT proteins and new clues for future studies of the in vivo transport activities and physiological functions of the different ENT proteins in Arabidopsis plants.展开更多
Acute on chronic liver failure(ACLF)is a disease entity with a high mortality rate.The acute event arises from drugs and toxins,viral infections,bacterial sepsis,interventions(both surgical and non-surgical)and vascul...Acute on chronic liver failure(ACLF)is a disease entity with a high mortality rate.The acute event arises from drugs and toxins,viral infections,bacterial sepsis,interventions(both surgical and non-surgical)and vascular events on top of a known or occult chronic liver disease.ACLF secondary to reactivation of chronic hepatitis B virus is a distinct condition;the high mortality of which can be managed in the wake of new potent antiviral therapy.For example,lamivudine and entecavir use has shown definite short-term survival benefits,even though drug resistance is a concern in the former.The renoprotective effects of telbivudine have been shown in a few studies to be useful in the presence of renal dysfunction.Monotherapy with newer agents such as tenofovir and a combination of nucleos(t)ides is promising for improving survival in this special group of liver disease patients.This review describes the current status of potent antiviral therapy in patient with acute on chronic liver failure due to reactivation of chronic hepatitis B,thereby providing an algorithm in management of such patients.展开更多
The chemical synthesis of Guanine arabinoside (ara-G) is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine ara...The chemical synthesis of Guanine arabinoside (ara-G) is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine arabinoside (ara-DA) was first synthesized with purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase produced by Enterobacter aerogenes DGW-07. The conversion yield of ara-DA could reach above 90% when the reaction liquid contained 30 mmol·L^-1 uracil arabinoside as arabinose donor, 10 mmol·L^- 1 2,6-diaminopurine as arabinose acceptor in pH 7.0 20 mmol·L^-1 phosphate buffer, and reacted at 60℃ for 48h. Then, ara-DA was effectively transformed into ara-G with adenylate deaminase produced by Aspergillus oryzae DAW-01. The total process had no complex separation and purification.展开更多
文摘Hepatitis B virus(HBV)reactivation(HBVr)represents a severe and potentially life-threatening condition,and preventive measures are available through blood test screening or prophylactic therapy administration.The assessment of HBVr traditionally considers factors such as HBV profile,including hepatitis B surface antigen(HBsAg)and antibody to hepatitis B core antigen,along with type of medication(chemotherapy;immunomodulants).Nevertheless,consideration of possible patient’s underlying tumor and the specific malignancy type(solid or hematologic)plays a crucial role and needs to be assessed for decision-making process.
基金the National Natural Science Foundation of China(31972048,32272339)the National Key R&D Program of China(2021YFD2100104)for financial support。
文摘Hyperuricemia is a metabolic disorder caused by abnormal purine metabolism,resulting in abnormally high serum uric acid.In this study,a novel Levilactobacillus brevis PDD-5 isolated from salty vegetables was verified with the function of alleviating hyperuricemia.The relevant effects of L.brevis PDD-5 in lowering uric acid were analyzed by in vitro and in vivo experiments.The results showed that the L.brevis PDD-5 has(68.86±15.46)%of inosine uptake capacity and(95.75±3.30)%of guanosine uptake capacity in vitro.Oral administration of L.brevis PDD-5 to hyperuricemia rats reduced uric acid,creatinine,and urea nitrogen in serum,as well as decreased inosine and guanosine levels in the intestinal contents of rats.Analysis of relevant markers in the kidney by ELISA kits revealed that L.brevis PDD-5 alleviated oxidative stress and inflammation.Moreover,the gene expression of uric acid transporter 1(URAT1)and glucose transporter 9(GLUT9)was down-regulated,and the gene expression of organic anion transporter 1(OAT1)was up-regulated after treatment with L.brevis PDD-5.Western blot analysis showed that L.brevis PDD-5 alleviated hyperuricemia-induced kidney injury through the NLRP3 pathway.The se findings suggest that L.brevis PDD-5 can lower uric acid,repair kidney damage,and also has the potential to prevent uric acid nephropathy.
文摘This editorial commented on an article in the World Journal of Gastroenterology titled“Risks of Reactivation of Hepatitis B Virus in Oncological Patients Using Tyrosine Kinase-Inhibitors:Case Report and Literature Analysis”by Colapietro et al.In this editorial,we focused on providing a more comprehensive exploration of hepatitis B virus reactivation(HBVr)associated with the usage of tyrosine kinase inhibitors(TKIs).It includes insights into the mechanisms underlying HBV reactivation,the temporal relationship between TKIs and HBV reactivation,and preventive measures.The aim is to understand the need for nucleos(t)ide analogs(NAT)and serial blood tests for early recognition of reactivation and acute liver injury,along with management strategies.TKIs are considered to be an intermediate(1%-10%)of HBVr.Current guidelines stipulate that patients receiving therapy with high or moderate risks of reactivation or recent cancer diagnosis must have at least tested hepatitis B surface antigen,anti-hepatitis B core antigen(HBc),and anti-hepatitis B surface antibody.Anti-HBc screening in highly endemic areas means people with negative tests should be vaccinated against HBV.Nucleoside or nucleotide analogs(NAs)like entecavir(ETV),tenofovir disoproxil fumarate(TDF),and tenofovir alafenamide(TAF)form the basis of HBV reactivation prophylaxis and treatment during immunosuppression.Conversely,lamivudine,telbivudine,and adefovir are generally discouraged due to their reduced antiviral efficacy and higher risk of fostering drug-resistant viral strains.However,these less effective NAs may still be utilized in cases where ETV,TDF,and TAF are not feasible treatment options.
文摘Aim: To compare the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia, and to study the effect of humidity and heat on the content of nucleosides. Methods: The contents of nucleosides were determined by using high performance capillary electrophoresis (HPCE). Beckman P/ACE System 5010 apparatus equipped with a UV detector and a Beckman untreated fused-silica capillary (57 cm 75 mm, 50 cm effective length) was used. Before sample injection, the capillary was rinsed with 1 molL-1 sodium hydroxide solution and running buffer for 5 min, respectively. A voltage of 20 kV was applied for the separation. Pressure injection was 586 kPa for 6 seconds, and the wavelength of detector was 254 nm. The running time was 20 min at 20 oC. The effect of humidity and heat on the contents of nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia was observed for 1, 3, 5 and 10 days at temperature 40 oC, and relative humidity 75%. Results: The content of nucleosides from natural Cordyceps sinensis was higher than that from cultured Cordyceps mycelia. But the contents of nucleosides from freshly collected natural Cordyceps sinensis were very low, even below the limit of quantitation. The contents of nucleosides from natural Cordyceps sinensis were significantly increased by humidity and heat, but this phenomenon was not observed in cultured Cordyceps mycelia. Conclusion: There are differences between the nucleosides from natural Cordyceps sinensis and cultured Cordyceps mycelia. The nucleosides in natural Cordyceps sinensis may be derived from the degradation of nucleic acids. This implies that adenosine being used for the quality control of natural Cordyceps sinensis may have to be reconsidered.
基金National Natural Science Foundation of China(Grant No.20472007)the Research Found for the DocroralProgram of Higher Education
文摘For investigating the biological function of ADPR, four novel analogues (compounds 2-5) in which the pyrophosphate linkage was replaced by the aspartic acid dipeptide were synthesized. 5'-Amino adenosine or its analogues was used as the starting material, liquid phase peptide synthesis strategy was used to construct these ADPR analogues. The structures were characterized by 1H NMR and HRMS spectra. This study provides a versatile synthesis of peptide modified ADPR analogues and helps to understand the structure-activity relationship of ADPR.
文摘Aim To quantitatively determine five nucleosides and nucleobases, including cytidine, uridine, guanosine, adenosine and uracil in different parts of Panax notoginseng. Methods Separation was performed on a Zorbax SB-Aq column using a gradient elution with mobile phase of 8 mmol^L-1 ammonium acetate aqueous solution (A) and methanol (B). The assay was carried out at a flow rate of 1 mL·min^-1 at 25 ℃ with the diode-array detection at 260 nm. Results Cytidine, uridine, guanosine, adenosine and uracil had good linearity in the ranges of 1.79 - 57.40 μg·mL^-1 (r^2 = 1.0000), 3.30 - 105.60 μg·mL^-1 (r^2 = 1.0000), 3.09 - 98.80 μg·mL^ -1(r^2 = 0.9999), 2.77 - 88.60 μg·mL^-1 (r^2 = 1.0000) and 0.38 - 12.30 μg·mL ^-1 (r^2 = 1.0000) with average recoveries of 93.9%, 96.5%, 92.7%, 93.2% and 98.8%, respectively. The content of cytidine, uridine, guanosine, adenosine and uracil in different parts of P. notogingeng were significantly different. Conclusion This is the first report on quantitative determination of nucleosides and nucleobases in P notoginseng.
基金Supported by Grant from the Youth scientific research fund,No.2013207059
文摘AIM: To evaluate the clinical outcomes of 240-wk treatment with entecavir(0.5 mg) in Chinese nucleosidenaive patients with cirrhosis.METHODS: A total of 204 nucleoside-naive patients with compensated(n = 96) or decompensated(n = 108) hepatitis B virus(HBV)-induced cirrhosis at the Department of Gastroenterology of the China-Japan Union Hospital(Jilin University, Changchun, China) who were treated with entecavir(0.5 mg) for 240 wk were enrolled in this study. Liver biopsy samples obtained from 38 patients prior to treatment(baseline) and at week 240 were evaluated by different independent histopathologists. Efficacy assessments included the proportions of patients who achieved an HBV DNA level < 500 copies/m L, the association of interleukin-28 B genetic variation with antivirus therapy, clinical outcomes, and histologic improvement. Changes in liver disease severity were analyzed, and liver histologic evaluation was performed in 38 patients with paired biopsies. Student t tests were used to compare the means of continuous variables between the groups, and the proportions of patients who achieved the endpoints were compared using the χ2 test.RESULTS: At week 240, 87.5% of the patients with compensated cirrhosis and 92.6% of the patients with decompensated cirrhosis achieved a HBV DNA level < 500 copies/m L. Three patients had genotypic entecavir resistance within the 240-wk period. No significant association was observed between virologic response and interleukin-28 genotype(CT, 88.2% vs CC, 90.6%). The proportion of patients with Child-Pughclass A disease was significantly increased at week 240(68%) from the baseline(47%; P < 0.01). The proportion of patients with Child-Pugh class B disease was significantly decreased at week 240(25%) from the baseline(39%; P = 0.02). In the patients with paired liver biopsies, the mean reduction in the Knodell necroinflammatory score from the baseline was 3.58 ± 1.03 points(7.11 ± 1.80 vs 3.53 ± 1.35, P < 0.01). The mean reduction in Ishak fibrosis score from the baseline was 1.26 ± 0.64 points(5.58 ± 0.50 vs 4.32 ± 0.81, P < 0.01).CONCLUSION: Entecavir is an effective treatment option for patients with HBV-related compensated or decompensated cirrhosis that can result in sustained virologic suppression and histologic improvement.
基金Supported by the German BMBF and Network for competence in viral hepatitis
文摘Hepatitis B virus (HBV) infection is still the most common cause of hepatocellular carcinoma and liver drrhosis world wide. Recently, however, there has been quite dramatic improvement in the understanding of HBV assodated liver disease and its treatment. It has become dear that high viral replication is a major risk factor for the development of both cirrhosis and hepatocellular carcinoma. Early studies have shown lamivudine lowers the risk of HBV associated complications. There are currently three nucleos(t)ides licensed, in addition to interferon, and there are more drugs coming to the market soon. Interferon or its pegylated counterpart are still the only options for treatment with defined end points, while nudeos(t)ides therapy is used mostly for long term treatment. Combination therapies have not been shown to be superior to monotherapy in naive patients, however, the outcome depends on how the end point is defined. Interferon plus lamivudine achieves a higher viral suppression than either treatment alone, even though Hbe-seroconversion was not different after a one year treatment. HBV-genotypes emerge as relevant factors, with genotypes "A" and "B" responding relatively well to interferon, achieving up to 20% HBsAg clearance in the case of genotype "A". In addition to having a defined treatment duration, interferon has the advantage of lack- ing resistance selection, which is a major drawback for lamivudine and the other nucleos(t)ides. The emergence of resistance against adefovir and entecavir is some- what slower in na'fve compared to lamivudine resistant patients. Adefovir has a low resistance profile with 3%, 9%, 18%, and 28% after 2, 3, 4, and 5 years, respectively, while entecavir has rarely produced resistance in naive patients for up to 3 years.
文摘AIM:To investigate the effect of antiviral therapy with nucleoside analogs in hepatitis B virus(HBV)-related cirrhosis and esophageal varices.METHODS:Eligible patients with HBV-related cirrhosis and esophageal varices who consulted two tertiary hospitals in Beijing,China,the Chinese Second Artillery General Hospital and Chinese PLA General Hospital,were enrolled in the study from January 2005 to December 2009. Of 117 patients,79 received treatment with different nucleoside analogs and 38 served as controls. Bleeding rate,change in variceal grade and non-bleeding duration were analyzed. Multivariate Cox proportional hazard regression was used to identify factors related to esophageal variceal bleeding.antiviral group compared to the control group(29.1%vs 65.8%,P < 0.001). Antiviral therapy was an independent factor related to esophageal bleeding in multivariate analysis(HR = 11.3,P < 0.001). The mean increase in variceal grade per year was lower in the antiviral group(1.0 ± 1.3 vs 1.7 ± 1.2,P = 0.003). Nonbleeding duration in the antiviral group was prolonged in the Kaplan-Meier model. Viral load rebound was observed in 3 cases in the lamivudine group and in 1 case in the adefovir group,all of whom experienced bleeding. Entecavir and adefovir resulted in lower bleeding rates(17.2% and 28.6%,respectively) than the control(P < 0.001 and P = 0.006,respectively),whereas lamivudine(53.3%) did not(P = 0.531).CONCLUSION:Antiviral therapy delays the progression of esophageal varices and reduces bleeding risk in HBV-related cirrhosis,however,high-resistance agents tend to be ineffective for long-term treatment.
基金Supported by National 11th Five-Year Special Major Project for Infectious Diseases(No.2008zx10002-005-6)Collaborative Project between US and China on Major Liver Diseases(No. 2009DFA32450)+1 种基金The Capital Medical Research and Development(No.20072026)the Army Medical and Health Scientific Research Fund of China,No.06H057
文摘AIM:To investigate the survival rates and prognostic factors in patients with hepatitis B virus-related acuteon-chronic liver failure(HBV-ACLF).METHODS:Clinical data in hospitalized patients with HBV-ACLF admitted from 2006 to 2009 were retrospectively analyzed.Their general conditions and survival were analyzed by survival analysis and Cox regression analysis.RESULTS:A total of 190 patients were included in this study.The overall 1-year survival rate was 57.6%.Patients not treated with antiviral drugs had a significantly higher mortality[relative risk(RR)=0.609,P=0.014].The highest risk of death in patients with ACLF was associated with hepatorenal syndrome(HRS)(RR=2.084,P=0.026),while other significant factors were electrolyte disturbances(RR=2.062,P=0.010),and hepatic encephalopathy(HE)(RR=1.879,P<0.001).CONCLUSION:Antiviral therapy has a strong effect on the prognosis of the patients with HBV-ACLF by improving their 1-year survival rate.HRS,electrolyte disturbances,and HE also affect patient survival.
文摘Three hundred and fifty million people worldwide are estimated to be chronically infected with hepatitis B virus. 15%-40% of these subjects will develop cirrhosis, liver failure or hepatocellular carcinoma during their life. The treatment of chronic hepatitis B has improved dramatically over the last decade merits to the advent of nucleoside/nucleotide analogues and the use of pegylated interferons. Approved drugs for chronic hepatitis B treatment include: standard interferon- alpha 2b, pegylated interferon-alpha 2a, lamivudine, adefovir dipivoxil, and entecavir. Unfortunately, these agents are not effective in all patients and are associated with distinct side effects. Interferons have numerous side effects and nucleoside or nucleotide analogues, which are well tolerated, need to be used for prolonged periods, even indefinitely. However, prolonged treatment with nucleoside or nucleotide analogues is associated with a high rate of resistance. Telbivudine is a novel, orally administered nucleoside analogue for use in the treatment of chronic hepatitis B. In contrast to other nucleoside analogues, Telbivudine has not been associated with inhibition of mammalian DNA polymerase with mitochondrial toxicity. Telbivudine has demonstrated potent activity against hepatitis B with a significantly higher rate of response and superior viral suppression compared with lamivudine, the standard treatment. Telbivudine has been generally well tolerated, with a low adverse effect profile, and at its effective dose, no dose- limiting toxicity has been observed. Telbivudine is one of the most potent antiviral agents for chronic hepatitis B virus and was approved by the FDA in late 2006.
文摘AIM: To analyze the clinical features and risk factors of adverse reactions associated with telbivudine. METHODS: Clinical data were collected from cases that presented with serious adverse reactions to telbivudine. We analyzed general information and medicine status, clinical features, results of examination, and misdiagnosis. RESULTS: Out of 105 patients who were treated with telbivudine for hepatitis B in an outpatient department from January, 2007 to January, 2008, five presented with serious adverse drug reactions. Most of these five patients had used other nucleoside analogues in the past. Four were treated with a combination of telbivudine and interferon or another nucleoside analogue, while the other received an increased dose of telbivudine. The main adverse reactions were myalgia and general weakness. This was accompanied by cardiac arrhythmia in one patient, and nervous symptoms in three. Serum creatine kinase was elevated. The rate of misdiagnosis was high. CONCLUSION: The adverse reactions were related to telbivudine, but the biological mechanism of the reactions is not yet clear. Combination therapy with interferon or another nucleoside analogue and a high dose may increase the risk of adverse reactions.
基金Supported by Centers for Disease Control,Taiwan,Grant No.DOH 102-DC-1401
文摘Hepatitis B virus(HBV)infection is a leading cause of chronic hepatitis,liver cirrhosis,and hepatocellular carcinoma worldwide.Due to the shared modes of transmission,coinfection with HBV and human immunodeficiency virus(HIV)is not uncommon.It is estimatedthat 10%of HIV-infected patients worldwide are coinfected with HBV.In areas where an HBV vaccination program is implemented,the HBV seroprevalence has declined significantly.In HIV/HBV-coinfected patients,HBV coinfection accelerates immunologic and clinical progression of HIV infection and increases the risk of hepatotoxicity when combination antiretroviral therapy(cART)is initiated,while HIV infection increases the risk of hepatitis events,cirrhosis,and end-stage liver disease related to chronic HBV infection.With the advances in antiviral therapy,concurrent,successful longterm suppression of HIV and HBV replication can be achieved in the cART era.To reduce the disease burden of HBV infection among HIV-infected patients,adoption of safe sex practices,avoidance of sharing needles and diluent,HBV vaccination and use of cART containing tenofovir disoproxil fumarate plus emtricitabine or lamivudine are the most effective approaches.However,due to HIV-related immunosuppression,using increased doses of HBV vaccine and novel approaches to HBV vaccination are needed to improve the immunogenicity of HBV vaccine among HIV-infected patients.
基金the National Natural Science Foundations of China(document no.:81321002,81500860,81300888)a grant from 111 Project of Ministry of Education,China,for fi nancial support
文摘Herpes simplex virus (HSV), a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir (ACV) and related nucleoside analogues can successfully treat HSV infections, but the emergence of drug resistance to ACV has created a barrier for the treatment of HSV infections, especially in immunocompromised patients. There is an urgent need to explore new and effective tactics to circumvent drug resistance to HSV. This review summarises the current strategies in the development of new targets (the DNA helicase/primase (H/P) complex), new types of molecules (nature products) and new antiviral mechanisms (lethal mutagenesis of Janus-type nucleosides) to fight the drug resistance of HSV.
文摘Chronic hepatitis B virus infection affects about 400 million people around the globe and causes approximately a million deaths a year. Since the discovery of interferon-α as a therapeutic option the treatment of hepatitis B has evolved fast and management has become increasingly complicated. The amount of viral replication reflected in the viral load (HBV-DNA) plays an important role in the development of cirrhosis and hepatocellular carcinoma. The current treatment modalities for chronic hepatitis B are immunomodulatory (interferons) and antiviral suppressants (nucleoside and nucleotide analogues) all with their own advantages and limitations. An overview of the treatment efficacy for both immunomodulatory as antiviral compounds is provided in order to provide the clinician insight into the factors influencing treatment outcome. With nucleoside or nucleotide analogues suppression of viral replication by 5-7 log10 is feasible, but not all patients respond to therapy. Known factors influencing treatment outcome are viral load, ALT levels and compliance. Many other factors which might influence treatment are scarcely investigated. Identifying the factors associated with response might result in stopping rules, so treatment could be adapted in an early stage to provide adequate treatment and avoid the development of resistance. The efficacy of compounds for the treatment of mutant virus and the cross-resistance is largely unknown. However, genotypic and phenotypic testing as well as small clinical trials provided some data on efficacy in this population. Discontinuation of nucleoside or nucleotide analogues frequently results in viral relapse; however, some patients have a sustained response. Data on the risk factors for relapse are necessary in order to determine when treatment can be discontinued safely. In conclusion: chronic hepatitis B has become a treatable disease; however, much research is needed to tailor therapy to an individual patient, to predict the sustainability of response and determine the best treatment for those failing treatment.
文摘The ultimate goals of treating chronic hepatitis B(CHB)is prevention of hepatocellular carcinoma(HCC)and hepatic decompensation.Since the advent of effective antiviral drugs that appeared during the past two decades,considerable advances have been made not only in controlling hepatitis B virus(HBV)infection,but also in preventing and reducing the incidence of liver cirrhosis and HCC.Furthermore,several recent studies have suggested the possibility of reducing the incidence of recurrent or new HCC in patients even after they have developed HCC.Currently,six medications are available for HBV treatment including,interferon and five nucleoside/nucleotide analogues.In this review,we will examine the antiviral drugs and the progresses that have been made with antiviral treatments in the field of CHB.
基金Supported by National Natural Science Foundation of ChinaNo.81071354 and 81271833+4 种基金National "973’ ’ProjectNo.2012CB519001National Science and Technology Major Project of ChinaNo.2012ZX10002007-001-002No.2013ZX10002001
文摘All oral nucleoside analogues against hepatitis B virus,with an exception of telbivudine,have been reported causing lactic acidosis(LA).Here we report the first case of chronic hepatitis B developing severe refractory LA during telbivudine monotherapy.A 36-year-old man of Chinese origin received telbivudine antiviral treatment for chronic hepatitis B.After 11 mo of therapy,he developed anorexia,nausea,and vomiting with mild muscle weakness.The patient was found with elevated serum creatine phosphokinase up to 3683 U/L(upper limit of normal 170 U/L)and marked LA.LA did not resolve immediately following discontinuation of telbivudine.His condition began to improve after hemodialysis treatment for 16 times and usage of glucocorticosteroid.The patient fully recovered after 16 wk of treatment.This is the first documented case with severe LA caused by telbivudine monotherapy.Besides serum creatine phosphokinase,blood lactate level should also be closely monitored in patients receiving telbivudine.
基金This work was supported by grants from the National Natural Science Foundation of China (39770491) the Chinese Academy of Sciences (KSCX2-SW-304).
文摘Previous studies have shown that Arabidopsis equilibrative nucleoside transporters (AtENTs) possess transport activities when produced in yeast cells and are differentially expressed in Arabidopsis organs. Herein, we report further analysis on the nucleoside transport activities and transcriptional patterns of AtENT members. The recombinant proteins of AtENTs 3, 6, and 7, but not those of AtENTs 1, 2, 4, and 8, were found to transport thymidine with high affinity. Contrary to previ- ous suggestion that AtENT 1 may not transport uridine, this work showed that recombinant AtENT 1 was a pH-dependent and high-affinity transporter of uridine. When grown on MS plates, the AtENT3 knockout plants were more tolerant to the cytotoxic uridine analog 5-fluorouridine than wild-type plants and the knockout plants ofAtENT 1 or AtENT6. Con- sistent with this observation, the AtENT3 knockout line exhibited a significantly decreased ability to take up [^3H]uridine via the roots when compared with wild-type plants and the plants with mutated AtENT 1 or AtENT6. This indicates that AtENT3, but not AtENTs 1 and 6, is the main transporter for uridine uptake in Arabidopsis roots. The transcription of AtENTs 1, 3, 4, 6, 7, and 8 was regulated in a complex manner during leaf development and senescence. In contrast, the six AtENT members were coordinately induced during seed germination. This work provides new information on the transport properties of recombinant AtENT proteins and new clues for future studies of the in vivo transport activities and physiological functions of the different ENT proteins in Arabidopsis plants.
文摘Acute on chronic liver failure(ACLF)is a disease entity with a high mortality rate.The acute event arises from drugs and toxins,viral infections,bacterial sepsis,interventions(both surgical and non-surgical)and vascular events on top of a known or occult chronic liver disease.ACLF secondary to reactivation of chronic hepatitis B virus is a distinct condition;the high mortality of which can be managed in the wake of new potent antiviral therapy.For example,lamivudine and entecavir use has shown definite short-term survival benefits,even though drug resistance is a concern in the former.The renoprotective effects of telbivudine have been shown in a few studies to be useful in the presence of renal dysfunction.Monotherapy with newer agents such as tenofovir and a combination of nucleos(t)ides is promising for improving survival in this special group of liver disease patients.This review describes the current status of potent antiviral therapy in patient with acute on chronic liver failure due to reactivation of chronic hepatitis B,thereby providing an algorithm in management of such patients.
基金Supported by the Innovation Fund for Technology Based Firms from Ministry of Science and Technology of China(07C26213101283)
文摘The chemical synthesis of Guanine arabinoside (ara-G) is extremely complex, time-consuming, and seriously polluted. A two-step enzymatic synthesis process was developed to acquire ara-G easily. 2,6-Diaminopurine arabinoside (ara-DA) was first synthesized with purine nucleoside phosphorylase and pyrimidine nucleoside phosphorylase produced by Enterobacter aerogenes DGW-07. The conversion yield of ara-DA could reach above 90% when the reaction liquid contained 30 mmol·L^-1 uracil arabinoside as arabinose donor, 10 mmol·L^- 1 2,6-diaminopurine as arabinose acceptor in pH 7.0 20 mmol·L^-1 phosphate buffer, and reacted at 60℃ for 48h. Then, ara-DA was effectively transformed into ara-G with adenylate deaminase produced by Aspergillus oryzae DAW-01. The total process had no complex separation and purification.