Hepatitis B is a common yet serious infectious disease of the liver, affecting millions of people worldwide. Liver transplantation is the only possible treatment for those who advance to end-stage liver disease. Donor...Hepatitis B is a common yet serious infectious disease of the liver, affecting millions of people worldwide. Liver transplantation is the only possible treatment for those who advance to end-stage liver disease. Donors positive for hepatitis B virus(HBV) core antibody(HBc Ab) have previously been considered unsuitable for transplants. However, those who test negative for the more serious hepatitis B surface antigen can now be used as liver donors, thereby reducing organ shortages. Remarkable improvements have been made in the treatment against HBV, most notably with the development of nucleoside analogues(NAs), which markedly lessen cirrhosis and reduce post-transplantation HBV recurrence. However, HBV recurrence still occurs in many patients following liver transplantation due to the development of drug resistance and poor compliance with therapy. Optimized prophylactic treatment with appropriate NA usage is crucial prior to liver transplantation, and undetectable HBV DNA at the time of transplantation should be achieved. NA-based and hepatitis B immune globulin-based treatment regimens can differ between patients depending on the patients' condition, virus status, and presence of drug resistance. This review focuses on the current progress in applying NAs during the perioperative period of liver transplantation and the prophylactic strategies using NAs to prevent de novo HBV infection in recipients of HBc Ab-positive liver grafts.展开更多
BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants signif...BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants significantly improve the predictive sensitivity of TIL,more than 50%of cases of this toxicity cannot be predicted by this mutation.The potential use of the 6-thioguanine nucleotide(6TGN)level to predict TIL has been explored,but no decisive conclusion has been reached.Can we increase the predictive sensitivity based on 6TGN by subgrouping patients according to their NUDT15 R139C genotypes?AIM To determine the 6TGN cut-off levels after dividing patients into subgroups according to their NUDT15 R139C genotypes.METHODS Patients’clinical and epidemiological characteristics were collected from medical records from July 2014 to February 2017.NUDT15 R139C,thiopurine S methyltransferase,and 6TGN concentrations were measured.RESULTS A total of 411 Crohn’s disease patients were included.TIL was observed in 72 individuals with a median 6TGN level of 323.4 pmol/8×10^8 red blood cells(RBC),which was not different from that of patients without TIL(P=0.071).Then,we compared the 6TGN levels based on NUDT15 R139C.For CC(n=342)and CT(n=65)genotypes,the median 6TGN level in patients with TIL was significantly higher than that in patients without(474.8 vs 306.0 pmol/8×10^8 RBC,P=9.4×10-^5;291.7 vs 217.6 pmol/8×10^8 RBC,P=0.039,respectively).The four TT carriers developed TIL,with a median 6TGN concentration of 135.8 pmol/8×10^8 RBC.The 6TGN cut-off levels were 411.5 and 319.2 pmol/8×108 RBC for the CC and CT groups,respectively.CONCLUSION The predictive sensitivity of TIL based on 6TGN is dramatically increased after subgrouping according to NUDT15 R139C genotypes.Applying 6TGN cut-off levels to adjust thiopurine therapies based on NUDT15 is strongly recommended.展开更多
Nucleoside analogues are first line chemotherapy in various severe diseases:AIDS(acquired immunodeficiency disease syndrome),cytomegalovirus infections,cancer,etc.However,many nucleoside analogues exhibit poor oral bi...Nucleoside analogues are first line chemotherapy in various severe diseases:AIDS(acquired immunodeficiency disease syndrome),cytomegalovirus infections,cancer,etc.However,many nucleoside analogues exhibit poor oral bioavailability because of their high polarity and low intestinal permeability.In order to get around this drawback,prodrugs have been utilized to improve lipophilicity by chemical modification of the parent drug.Alternatively,prodrugs targeting transporters present in the intestine have been applied to promote the transport of the nucleoside analogues.Valacyclovir and valganciclovir are two classic valine ester prodrugs transported by oligopeptide transporter 1.The ideal prodrug achieves delivery of a parent drug by attaching a non-toxic moiety that is stable during transport,but is readily degraded to the parent drug once at the target.This article presents advances of prodrug approaches for enhancing oral absorption of nucleoside analogues.展开更多
AIM: To explore the effects of the nucleoside analogues β-L-D4A and β-LPA on hepatitis B virus (HBV) promoters. METHODS: Four HBV promoters were amplified by polymerase chain reaction (PCR) and subcloned into ...AIM: To explore the effects of the nucleoside analogues β-L-D4A and β-LPA on hepatitis B virus (HBV) promoters. METHODS: Four HBV promoters were amplified by polymerase chain reaction (PCR) and subcloned into the expression vector pEGFP-1. The four recombinants controlled by HBV promoters were confirmed by restriction analysis and sequencing. Human hepatoma HepG2 cells transfected with the recombinant plasmids were treated with various concentrations of β-L-D4A and β-LPA. Then, enhanced green fluorescent protein (EGFP)-positive cells were detected by fluorescence microscopy and using a fluorescence activated cell sorter RESULTS: Four HBV promoters were separately obtained and successfully cloned into pEGFP-1, Expression of EGFP under the control of the surface promoter (Sp) and the X promoter (Xp) was inhibited by β-L-D4A in a dosedependent manner, while expression of EGFP under the control of the core promoter (Cp) and Xp was inhibited by β-LPA in a dose-dependent manner. CONCLUSION: The two novel nucleoside analogues investigated here can inhibit the activities of HBV promoters in a dose-dependent manner. These findings may explain the mechanisms of action by which these two novel compounds inhibit HBV DNA replication.展开更多
Objective There are many clinical reports on traditional Chinese medicine(TCM)combined with nucleoside(acid)analogues(NAs)for the treatment of chronic hepatitis B(CHB),but its efficacy and safety are not completely cl...Objective There are many clinical reports on traditional Chinese medicine(TCM)combined with nucleoside(acid)analogues(NAs)for the treatment of chronic hepatitis B(CHB),but its efficacy and safety are not completely clear.This meta-analysis aims to evaluate the clinical efficacy and safety thus providing evidence for clinical applications.Methods We searched Chinese databases the China National Knowledge Infrastructure(CNKI),Wanfang Data,and China Science and Technology Journal Database(VIP),as well as English databases Pub Med and Cochrane Library,from time of establishment to April 14,2021.Literature quality was evaluated according to the bias risk assessment criteria of Cochrane Collaboration network.Rev Man 5.3 and Stata 12.0 software were used to perform this research.Results A total of 23 articles,3282 patients,and 25 TCM prescriptions were included in this study.NAs plus TCM remarkably improved the clinical total effective rate[Odds ratio(OR)=3.92,P<0.00001],TCM syndrome score(Mean difference=-3.73,P<0.00001),hepatitis B virus(HBV)DNA negative conversion rate(OR=1.49,P=0.0001),hepatitis Be antigen(HBe Ag)negative conversion rate(OR=2.03,P<0.00001),alanine aminotransferase levels[Std mean difference(SMD)=-0.95,P<0.00001],and aspartate aminotransferase levels(SMD=-0.70,P=0.0004).Adverse reaction rates did not increase in the combined treatment group(OR=0.97,P=0.84).A comprehensive analysis of the 25 TCM prescriptions suggested that the combination of spleen-strengthening prescriptions with NAs showed better effects than other prescriptions.Conclusion TCM in combination with NAs,demonstrated better clinical efficacy against CHB than NAs alone.In addition,the combination of spleen-strengthening prescriptions and NAs was identified as the best therapeutic strategy.However,more randomized controlled trials of high quality are needed to provide more reliable clinical basis for the application of TCM.展开更多
Objective: To study the effect of different nucleoside analogues on liver fibrosis and peripheral blood dendritic cell function of patients with chronic hepatitis B. Methods: Patients with chronic hepatitis B who rece...Objective: To study the effect of different nucleoside analogues on liver fibrosis and peripheral blood dendritic cell function of patients with chronic hepatitis B. Methods: Patients with chronic hepatitis B who received antiviral therapy in Infectious Diseases Hospital of Shanghai Huangpu District between April 2014 and October 2016 were selected as the research subjects and divided into 3 groups, group A received entecavir therapy, group B received adefovir dipivoxil therapy and group C received lamivudine therapy. 24 weeks and 48 weeks after treatment, the levels of liver fibrosis indexes in serum as well the levels of DC and the expression of surface markers in peripheral blood of the three groups were measured respectively. Results: After treatment, serum hyaluronic acid (HA), procollagen III (PC-III), laminin (LN) and collagen type IV (C-IV) levels of all groups were significantly lower than those before treatment, and the number of myeloid DC (mDC) and plasmacytoid DC (pDC) in peripheral blood as well as the expression levels of DC surface molecules CD80, CD86, CD1αand HLA-DR in peripheral blood were significantly higher than those before treatment. After treatment, the serum levels of HA, PC-III, LN and C-IV in group A were significantly lower than those in group B and C, and the number of mDC and pDC in peripheral blood as well as the expression of DC surface molecules CD80, CD86, CD1α and HLA-DR in peripheral blood were significantly higher than those in group B and C. Conclusion: Antiviral therapy by nucleoside analogues can effectively inhibit liver fibrosis and improve peripheral blood DC function in patients with chronic hepatitis B, and Entecavir function is better than that of adefovir dipivoxil and lamivudine.展开更多
AIM: To determine the relationship between host immunity and the characteristics of viral infection or nucleoside analogues (NAs) themselves in patients with chronic hepatitis B (CHB) receiving NA therapy.
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
An efficient protocol for the synthesis of N^6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 rain under microwave irradiation. Us...An efficient protocol for the synthesis of N^6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 rain under microwave irradiation. Using water as solvent makes our method eco-friendly and easy to handle with.展开更多
We measured the erythrocyte levels of principal nucleotides (ATP, ADP, AMP, GTP, GDP, GMP, IMP), nucleosides (Ado, Guo, Ino) and Hyp with HPLC. Purine concentrations were determined in the erythrocytes of 36 type 1 an...We measured the erythrocyte levels of principal nucleotides (ATP, ADP, AMP, GTP, GDP, GMP, IMP), nucleosides (Ado, Guo, Ino) and Hyp with HPLC. Purine concentrations were determined in the erythrocytes of 36 type 1 and 40 type 2 diabetic patients. The increased dephosphorylation of adenine and guanine nucleotides, indicated by increased Ado, Ino, Guo and Hyp concentrations as the products of purine nucleotide degradation, suggests serious energy metabolism disruptions in diabetes. An increase in AMP, GMP, IMP concentrations, as well as a decrease in AEC and GEC values, points to significant alterations in erythrocyte purine nucleotide concentration.展开更多
Two sets of degenerate oligonucleotide primers were designed according to amino acid conserved regions of reported plant disease resistance genes which encode proteins that contain nucleotide-binding site and leucine-...Two sets of degenerate oligonucleotide primers were designed according to amino acid conserved regions of reported plant disease resistance genes which encode proteins that contain nucleotide-binding site and leucine-rich repeats(NBS-LRR), and the plant disease resistance genes which encode serine/threonine protein kinase(STK). By polymerase chain reaction(PCR), disease resistance gene analogues have been amplified from three wild rice species in Yunnan Province, China. The DIN A fragments from amplification have been cloned into the pGEM-T vector respectively. Sequencing of the DNA fragments indicated that 7 classes, 2 classes and 6 classes NBS-LRR disease resistance gene analogues from Oryza rufipogon Griff. , Oryza officinalis Wall. , and Oryza meyeriana Baill. were obtained respectively. The two representative fragments of TO12 from Oryza officinalis Wall, and TR19 from Oryza rufipogon Griff, belong to the same class and homology of their sequences are 100%. The result shows that the sequences of the same class disease resistance gene analogues have no difference among different species of wild rice. 5 classes STK disease resistance gene analogues were also obtained among which 4 classes from Oryza rufipogon Griff. , 1 class from Oryza officinalis Wall. By comparison analysis of amino acid sequences. we found that the obtained disease resistance gene analogues have very low identity(low to 25%) with the reported disease resistance gene L6, N, Bs2, Prf, Pto, Lr10 and Xa21 etc. The finding suggests that the obtained disease resistance gene analogues are analogues of putative disease resistance genes that have not been isolated so far.展开更多
At present, there is no method for identifying meat frozen in a thermal state acceptable for production control. The role of free nucleotides in the processes of refrigeration and storage of meat, affecting the struct...At present, there is no method for identifying meat frozen in a thermal state acceptable for production control. The role of free nucleotides in the processes of refrigeration and storage of meat, affecting the structural and mechanical properties of muscle tissue, the formation of taste and its biological value is known. In this article we compared methods for identifying the thermal state of meat based on the determination of the composition and content of free nucleotides by high-performance liquid chromatography (HPLC) and spectrophotometry [SF]. High-purity reference substances were used: free nucleotides—ATP, ADP, AMP, IMP and nucleosides-inosine and hypoxanthine. It has been experimentally established that the characteristic peaks of the absorption spectra for extracts of free nucleotides of meat frozen depended from thermal state of meat. The content of ATP is 21.8 times higher in meat frozen in a fresh state, and the amount of IMF is 12.3 times lower than in meat frozen after cooling. The results of studies of meat frozen using the HPLC method and the developed SF method show the adequacy of the data obtained by both methods. SF-method based on the determination of the optical density of the extracts of free nucleotides is recommended to justify the choice of technological process meat defrost modes.展开更多
The prognosis of pancreatic cancer is poor with the overall 5-year survival rate of less than 5%changing minimally over the past decades and future projections predicting it developing into the second leading cause of...The prognosis of pancreatic cancer is poor with the overall 5-year survival rate of less than 5%changing minimally over the past decades and future projections predicting it developing into the second leading cause of cancer related mortality within the next decade.Investigations into the mechanisms of pancreatic cancer development,progression and acquired chemoresistance have been constant for the past few decades,thus resulting in the identification of human nucleoside transporters and factors affecting cytotoxic uptake via said transporters.This review summaries the aberrant expression and role of human nucleoside transports in pancreatic cancer,more specifically human equilibrative nucleoside transporter 1/2(hENT1,hENT2),and human concentrative nucleoside transporter 1/3(hCNT1,hCNT3),while briefly discussing the connection and importance between these nucleoside transporters and mucins that have also been identified as being aberrantly expressed in pancreatic cancer.The review also discusses the incidence,current diagnostic techniques as well as the current therapeutic treatments for pancreatic cancer.Furthermore,we address the importance of chemoresistance in nucleoside analogue drugs,in particular,gemcitabine and we discuss prospective therapeutic treatments and strategies for overcoming acquired chemoresistance in pancreatic cancer by the enhancement of human nucleoside transporters as well as the potential targeting of mucins using a combination of mucolytic compounds with cytotoxic agents.展开更多
基金Supported by National High Technology Research and Development Program(863 Program)of China,Grant No.2012AA021001
文摘Hepatitis B is a common yet serious infectious disease of the liver, affecting millions of people worldwide. Liver transplantation is the only possible treatment for those who advance to end-stage liver disease. Donors positive for hepatitis B virus(HBV) core antibody(HBc Ab) have previously been considered unsuitable for transplants. However, those who test negative for the more serious hepatitis B surface antigen can now be used as liver donors, thereby reducing organ shortages. Remarkable improvements have been made in the treatment against HBV, most notably with the development of nucleoside analogues(NAs), which markedly lessen cirrhosis and reduce post-transplantation HBV recurrence. However, HBV recurrence still occurs in many patients following liver transplantation due to the development of drug resistance and poor compliance with therapy. Optimized prophylactic treatment with appropriate NA usage is crucial prior to liver transplantation, and undetectable HBV DNA at the time of transplantation should be achieved. NA-based and hepatitis B immune globulin-based treatment regimens can differ between patients depending on the patients' condition, virus status, and presence of drug resistance. This review focuses on the current progress in applying NAs during the perioperative period of liver transplantation and the prophylactic strategies using NAs to prevent de novo HBV infection in recipients of HBc Ab-positive liver grafts.
基金Supported by the National Natural Science Foundation of China,No.81573507,No.81473283,No.81173131,and No.81320108027Guangdong Provincial Key Laboratory Construction Foundation,No.2017B030314030+1 种基金The National Key Research and Development Program,No.2016YFC0905003the 111 Project,No.B16047
文摘BACKGROUND Thiopurine-induced leukopenia(TIL)is a life-threatening toxicity and occurs with a high frequency in the Asian population.Although nucleoside diphosphate-linked moiety X-type motif 15(NUDT15)variants significantly improve the predictive sensitivity of TIL,more than 50%of cases of this toxicity cannot be predicted by this mutation.The potential use of the 6-thioguanine nucleotide(6TGN)level to predict TIL has been explored,but no decisive conclusion has been reached.Can we increase the predictive sensitivity based on 6TGN by subgrouping patients according to their NUDT15 R139C genotypes?AIM To determine the 6TGN cut-off levels after dividing patients into subgroups according to their NUDT15 R139C genotypes.METHODS Patients’clinical and epidemiological characteristics were collected from medical records from July 2014 to February 2017.NUDT15 R139C,thiopurine S methyltransferase,and 6TGN concentrations were measured.RESULTS A total of 411 Crohn’s disease patients were included.TIL was observed in 72 individuals with a median 6TGN level of 323.4 pmol/8×10^8 red blood cells(RBC),which was not different from that of patients without TIL(P=0.071).Then,we compared the 6TGN levels based on NUDT15 R139C.For CC(n=342)and CT(n=65)genotypes,the median 6TGN level in patients with TIL was significantly higher than that in patients without(474.8 vs 306.0 pmol/8×10^8 RBC,P=9.4×10-^5;291.7 vs 217.6 pmol/8×10^8 RBC,P=0.039,respectively).The four TT carriers developed TIL,with a median 6TGN concentration of 135.8 pmol/8×10^8 RBC.The 6TGN cut-off levels were 411.5 and 319.2 pmol/8×108 RBC for the CC and CT groups,respectively.CONCLUSION The predictive sensitivity of TIL based on 6TGN is dramatically increased after subgrouping according to NUDT15 R139C genotypes.Applying 6TGN cut-off levels to adjust thiopurine therapies based on NUDT15 is strongly recommended.
基金the Project for Sci-ence and Technology Plan of Liaoning Province(No.2011225020).
文摘Nucleoside analogues are first line chemotherapy in various severe diseases:AIDS(acquired immunodeficiency disease syndrome),cytomegalovirus infections,cancer,etc.However,many nucleoside analogues exhibit poor oral bioavailability because of their high polarity and low intestinal permeability.In order to get around this drawback,prodrugs have been utilized to improve lipophilicity by chemical modification of the parent drug.Alternatively,prodrugs targeting transporters present in the intestine have been applied to promote the transport of the nucleoside analogues.Valacyclovir and valganciclovir are two classic valine ester prodrugs transported by oligopeptide transporter 1.The ideal prodrug achieves delivery of a parent drug by attaching a non-toxic moiety that is stable during transport,but is readily degraded to the parent drug once at the target.This article presents advances of prodrug approaches for enhancing oral absorption of nucleoside analogues.
基金Supported by The National Natural Science Foundation of China, No. 30330680
文摘AIM: To explore the effects of the nucleoside analogues β-L-D4A and β-LPA on hepatitis B virus (HBV) promoters. METHODS: Four HBV promoters were amplified by polymerase chain reaction (PCR) and subcloned into the expression vector pEGFP-1. The four recombinants controlled by HBV promoters were confirmed by restriction analysis and sequencing. Human hepatoma HepG2 cells transfected with the recombinant plasmids were treated with various concentrations of β-L-D4A and β-LPA. Then, enhanced green fluorescent protein (EGFP)-positive cells were detected by fluorescence microscopy and using a fluorescence activated cell sorter RESULTS: Four HBV promoters were separately obtained and successfully cloned into pEGFP-1, Expression of EGFP under the control of the surface promoter (Sp) and the X promoter (Xp) was inhibited by β-L-D4A in a dosedependent manner, while expression of EGFP under the control of the core promoter (Cp) and Xp was inhibited by β-LPA in a dose-dependent manner. CONCLUSION: The two novel nucleoside analogues investigated here can inhibit the activities of HBV promoters in a dose-dependent manner. These findings may explain the mechanisms of action by which these two novel compounds inhibit HBV DNA replication.
基金We thank for the funding support from the Hundred Talents Program of Hunan Province(No.9999004007)the Startup grant of Hunan University of Chinese Medicine(No.999900201107).
文摘Objective There are many clinical reports on traditional Chinese medicine(TCM)combined with nucleoside(acid)analogues(NAs)for the treatment of chronic hepatitis B(CHB),but its efficacy and safety are not completely clear.This meta-analysis aims to evaluate the clinical efficacy and safety thus providing evidence for clinical applications.Methods We searched Chinese databases the China National Knowledge Infrastructure(CNKI),Wanfang Data,and China Science and Technology Journal Database(VIP),as well as English databases Pub Med and Cochrane Library,from time of establishment to April 14,2021.Literature quality was evaluated according to the bias risk assessment criteria of Cochrane Collaboration network.Rev Man 5.3 and Stata 12.0 software were used to perform this research.Results A total of 23 articles,3282 patients,and 25 TCM prescriptions were included in this study.NAs plus TCM remarkably improved the clinical total effective rate[Odds ratio(OR)=3.92,P<0.00001],TCM syndrome score(Mean difference=-3.73,P<0.00001),hepatitis B virus(HBV)DNA negative conversion rate(OR=1.49,P=0.0001),hepatitis Be antigen(HBe Ag)negative conversion rate(OR=2.03,P<0.00001),alanine aminotransferase levels[Std mean difference(SMD)=-0.95,P<0.00001],and aspartate aminotransferase levels(SMD=-0.70,P=0.0004).Adverse reaction rates did not increase in the combined treatment group(OR=0.97,P=0.84).A comprehensive analysis of the 25 TCM prescriptions suggested that the combination of spleen-strengthening prescriptions with NAs showed better effects than other prescriptions.Conclusion TCM in combination with NAs,demonstrated better clinical efficacy against CHB than NAs alone.In addition,the combination of spleen-strengthening prescriptions and NAs was identified as the best therapeutic strategy.However,more randomized controlled trials of high quality are needed to provide more reliable clinical basis for the application of TCM.
文摘Objective: To study the effect of different nucleoside analogues on liver fibrosis and peripheral blood dendritic cell function of patients with chronic hepatitis B. Methods: Patients with chronic hepatitis B who received antiviral therapy in Infectious Diseases Hospital of Shanghai Huangpu District between April 2014 and October 2016 were selected as the research subjects and divided into 3 groups, group A received entecavir therapy, group B received adefovir dipivoxil therapy and group C received lamivudine therapy. 24 weeks and 48 weeks after treatment, the levels of liver fibrosis indexes in serum as well the levels of DC and the expression of surface markers in peripheral blood of the three groups were measured respectively. Results: After treatment, serum hyaluronic acid (HA), procollagen III (PC-III), laminin (LN) and collagen type IV (C-IV) levels of all groups were significantly lower than those before treatment, and the number of myeloid DC (mDC) and plasmacytoid DC (pDC) in peripheral blood as well as the expression levels of DC surface molecules CD80, CD86, CD1αand HLA-DR in peripheral blood were significantly higher than those before treatment. After treatment, the serum levels of HA, PC-III, LN and C-IV in group A were significantly lower than those in group B and C, and the number of mDC and pDC in peripheral blood as well as the expression of DC surface molecules CD80, CD86, CD1α and HLA-DR in peripheral blood were significantly higher than those in group B and C. Conclusion: Antiviral therapy by nucleoside analogues can effectively inhibit liver fibrosis and improve peripheral blood DC function in patients with chronic hepatitis B, and Entecavir function is better than that of adefovir dipivoxil and lamivudine.
基金Supported by The Shanghai Natural Science Fund,No.09ZR1400500the National Natural Science Foundation of China,No.30972600+1 种基金the GuangHui Fund of Hepatitis Prevention Fund Committee China,No.GHZ20100204the Shanghai Health Bureau Fund,No.2012092
文摘AIM: To determine the relationship between host immunity and the characteristics of viral infection or nucleoside analogues (NAs) themselves in patients with chronic hepatitis B (CHB) receiving NA therapy.
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.
基金the National Natural Science Foundation of China(No.20372018)
文摘An efficient protocol for the synthesis of N^6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 rain under microwave irradiation. Using water as solvent makes our method eco-friendly and easy to handle with.
文摘We measured the erythrocyte levels of principal nucleotides (ATP, ADP, AMP, GTP, GDP, GMP, IMP), nucleosides (Ado, Guo, Ino) and Hyp with HPLC. Purine concentrations were determined in the erythrocytes of 36 type 1 and 40 type 2 diabetic patients. The increased dephosphorylation of adenine and guanine nucleotides, indicated by increased Ado, Ino, Guo and Hyp concentrations as the products of purine nucleotide degradation, suggests serious energy metabolism disruptions in diabetes. An increase in AMP, GMP, IMP concentrations, as well as a decrease in AEC and GEC values, points to significant alterations in erythrocyte purine nucleotide concentration.
文摘Two sets of degenerate oligonucleotide primers were designed according to amino acid conserved regions of reported plant disease resistance genes which encode proteins that contain nucleotide-binding site and leucine-rich repeats(NBS-LRR), and the plant disease resistance genes which encode serine/threonine protein kinase(STK). By polymerase chain reaction(PCR), disease resistance gene analogues have been amplified from three wild rice species in Yunnan Province, China. The DIN A fragments from amplification have been cloned into the pGEM-T vector respectively. Sequencing of the DNA fragments indicated that 7 classes, 2 classes and 6 classes NBS-LRR disease resistance gene analogues from Oryza rufipogon Griff. , Oryza officinalis Wall. , and Oryza meyeriana Baill. were obtained respectively. The two representative fragments of TO12 from Oryza officinalis Wall, and TR19 from Oryza rufipogon Griff, belong to the same class and homology of their sequences are 100%. The result shows that the sequences of the same class disease resistance gene analogues have no difference among different species of wild rice. 5 classes STK disease resistance gene analogues were also obtained among which 4 classes from Oryza rufipogon Griff. , 1 class from Oryza officinalis Wall. By comparison analysis of amino acid sequences. we found that the obtained disease resistance gene analogues have very low identity(low to 25%) with the reported disease resistance gene L6, N, Bs2, Prf, Pto, Lr10 and Xa21 etc. The finding suggests that the obtained disease resistance gene analogues are analogues of putative disease resistance genes that have not been isolated so far.
文摘At present, there is no method for identifying meat frozen in a thermal state acceptable for production control. The role of free nucleotides in the processes of refrigeration and storage of meat, affecting the structural and mechanical properties of muscle tissue, the formation of taste and its biological value is known. In this article we compared methods for identifying the thermal state of meat based on the determination of the composition and content of free nucleotides by high-performance liquid chromatography (HPLC) and spectrophotometry [SF]. High-purity reference substances were used: free nucleotides—ATP, ADP, AMP, IMP and nucleosides-inosine and hypoxanthine. It has been experimentally established that the characteristic peaks of the absorption spectra for extracts of free nucleotides of meat frozen depended from thermal state of meat. The content of ATP is 21.8 times higher in meat frozen in a fresh state, and the amount of IMF is 12.3 times lower than in meat frozen after cooling. The results of studies of meat frozen using the HPLC method and the developed SF method show the adequacy of the data obtained by both methods. SF-method based on the determination of the optical density of the extracts of free nucleotides is recommended to justify the choice of technological process meat defrost modes.
文摘The prognosis of pancreatic cancer is poor with the overall 5-year survival rate of less than 5%changing minimally over the past decades and future projections predicting it developing into the second leading cause of cancer related mortality within the next decade.Investigations into the mechanisms of pancreatic cancer development,progression and acquired chemoresistance have been constant for the past few decades,thus resulting in the identification of human nucleoside transporters and factors affecting cytotoxic uptake via said transporters.This review summaries the aberrant expression and role of human nucleoside transports in pancreatic cancer,more specifically human equilibrative nucleoside transporter 1/2(hENT1,hENT2),and human concentrative nucleoside transporter 1/3(hCNT1,hCNT3),while briefly discussing the connection and importance between these nucleoside transporters and mucins that have also been identified as being aberrantly expressed in pancreatic cancer.The review also discusses the incidence,current diagnostic techniques as well as the current therapeutic treatments for pancreatic cancer.Furthermore,we address the importance of chemoresistance in nucleoside analogue drugs,in particular,gemcitabine and we discuss prospective therapeutic treatments and strategies for overcoming acquired chemoresistance in pancreatic cancer by the enhancement of human nucleoside transporters as well as the potential targeting of mucins using a combination of mucolytic compounds with cytotoxic agents.