Amidst growing environmental protection intensity by the Chinese government, this paper investigates the effects of environmental regulation on China's industrial pollution treatment productivity and environmental TF...Amidst growing environmental protection intensity by the Chinese government, this paper investigates the effects of environmental regulation on China's industrial pollution treatment productivity and environmental TFP. By estimating China's pollution treatment productivity between 2001 and 2008 and analyzing environmental regulation intensity and the effects of the relevant factors and pollution treatment productivity using panel data, this paper discovers that (1) pollution treatment productivity contributed a significant share of about 40% to industrial environmental TFP during the investigation period; (2) environmental regulation may not necessarily cause adverse impacts on pollution treatment efficiency and productivity but demonstrates a U-shaped relationship: when the share of pollution treatment cost in industrial value-added is above the range of 3.8%-5.1%, environmental regulation is likely to promote pollution treatment productivity and thus environmental TFP Judging by the estimation result, enhancing environmental protection and expediting the development of ecological civilization are conducive to China "s economic transition towards an intensive, efficient, circular, and sustainable development pattern. China's current industrial development has the capacity to tolerate a rather demanding level of pollution treatment and management and China needs to further rely on energy conservation and the environmental production industries to promote the progress of pollution treatment technologies.展开更多
In the article, status quo of oil pollution in China's offshore area was in- troduced, and the sources of oil pollution in the ocean were analyzed. Furthermore, the possible hazards of marine oil pollution were discu...In the article, status quo of oil pollution in China's offshore area was in- troduced, and the sources of oil pollution in the ocean were analyzed. Furthermore, the possible hazards of marine oil pollution were discussed and related countermea- sures were proposed, including implementation of laws and regulations, enhancing awareness of environment protection, improvement of pollution monitoring and early warning mechanism, physical treatment, chemical treatment and biological treatment. With economy development, the demand of oil is increasing accordingly. Hence, oil pollution has become an urgent issue to be solved for better exploration of oil and protection of marine environment.展开更多
The research introduced pollution caused by animal farming on waters,agricultural lands,and atmosphere,as well as environment pollution and economic causes.Furthermore,a series of economic policies were proposed on pr...The research introduced pollution caused by animal farming on waters,agricultural lands,and atmosphere,as well as environment pollution and economic causes.Furthermore,a series of economic policies were proposed on preventing animal farming,such as definition of rights property,economic impetus and circular farming.展开更多
Objective: To investigate treatment efficacy for persistent chlamydial infection in the urogenital tract. Methods: 207 patients with persistent chlamydial urogenital infection were treated with tetracycline,azithrom...Objective: To investigate treatment efficacy for persistent chlamydial infection in the urogenital tract. Methods: 207 patients with persistent chlamydial urogenital infection were treated with tetracycline,azithromycin, ofloxacin or a combination of these.Result: 47.92%-68.60% of patients with persistent chlamydial urogenital infection were cured depending on the drug used. Ofloxacin had better results than tetracycline and azithromycin.Conclusion: Many patients were resistant to treatment with tetracycline and azithromycin. Ofloxacin proved effective.展开更多
This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitroge...This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3:50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10:50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.展开更多
Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds. All members of this family can cause acute and chronic hepatic infectio...Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds. All members of this family can cause acute and chronic hepatic infection, which in the case of human hepatitis B virus (HBV) constitutes a major global health problem. Although our knowledge about the molecular biology of these highly liver-specific viruses has profoundly increased in the last two decades, the mechanisms of attachment and productive entrance into the differentiated host hepatocytes are still enigmatic. The difficulties in studying hepadnaviral entry were primarily caused by the lack of easily accessible in vitro infection systems. Thus, for more than twenty years, differentiated primary hepatocytes from the respective species were the only in vitro models for both orthohepadnaviruses (e.g. HBV) and avihepadnaviruses (e.g. duck hepatitis B virus [DHBV]). Two important discoveries have been made recently regarding HBV: (1) primary hepatoo/tes from tree-shrews; i.e., Tupaia belangeri, can be substituted for primary human hepatocytes, and (2) a human hepatoma cell line (HepaRG) was established that gains susceptibility for HBV infection upon induction of differentiation in vitro. A number of potential HBV receptor candidates have been described in the past, but none of them have been confirmed to function as a receptor. For DHBV and probably all other avian hepadnaviruses, carboxypeptidase D (CPD) has been shown to be indispensable for infection, although the exact role of this molecule is still under debate. While still restricted to the use of primary duck hepatocytes (PDH), investigations performed with DHBV provided important general concepts on the first steps of hepadnaviral infection. However, with emerging data obtained from the new HBV infection systems, the hope that DHBV utilizes the same mechanism as HBV only partially held true. Nevertheless, both HBV and DHBV in vitro infection systems will help to: (1) functionally dissect the hepadnaviral entry pathways, (2) perform reverse genetics (e.g. test the fitness of escape mutants), (3) titrate and map neutralizing antibodies, (4) improve current vaccines to combat acute and chronic infections of hepatitis B, and (5) develop entry inhibitors for future clinical applications.展开更多
AIM: TO define the potential role of programmed death-i/programmed death-ligand (PD-1/PD-L) pathway in different hepatitis B virus (HBV) infection disease status; we examined the expression of PD-1 on antigen spe...AIM: TO define the potential role of programmed death-i/programmed death-ligand (PD-1/PD-L) pathway in different hepatitis B virus (HBV) infection disease status; we examined the expression of PD-1 on antigen specific CD8+T cells in peripheral blood of patients with chronic hepatitis B (CriB) and acute exacerbation of hepatitis B (AEHB) infection. METHODS: The PD-1 level on CD8+ T lymphocytes and the number of HBV specific CD8+ T lymphocytes in patients and healthy controls (HCs) were analyzed by staining with pentameric peptide-human leukocyte antigen2 (HLA2) complexes combined with flow cytometry. Real-time quantitative polymerase chain reaction (PCR) was used to measure the serum HBV- DNA levels. RESULTS: The level of PD-1 expression on total CD8+ T cells in CHB patients (13.86% ± 3.38%) was significantly higher than that in AEHB patients (6.80%± 2.19%, P 〈 0.01) and healthy individuals (4.63% ± 1.23%, P 〈 0.01). Compared to AEHB patients (0.81% ± 0.73%), lower frequency of HBV-specific CD8+ T cells was detected in chronic hepatitis B patients (0.37% ± 0.43%, P 〈 0.05). There was an inverse correlation between the strength of HBV-specific CD8+ T-cell response and the level of PD-1 expression. Besides, there was a significant positive correlation between HBV viral load and the percentage of PD-1 expression on CD8+ T cells in CriB and AEHB subjects (R = 0.541, P 〈 0.01). However, PD-1 expression was not associated with disease flare-ups as indicated by alanine aminotransferase (ALT) levels (R = 0.066, P 〉 0.05). CONCLUSION: Our results confirm previous reports that HBV specific CD8+T-cell response in the peripheral blood is more intense in patients with AEHB than in chronic hepatitis B wlth persistent viral infection. Moreover, there is a negative correlation between the level of PD-1 and the intensity of virus specific CD8+ T cell response.展开更多
Infection with H pylori leads to a persistent chronic inflammation of the gastric mucosa, thereby increasing the risk of distal gastric adenocarcinoma. Numerous studies have determined a clear correlation between Hpyl...Infection with H pylori leads to a persistent chronic inflammation of the gastric mucosa, thereby increasing the risk of distal gastric adenocarcinoma. Numerous studies have determined a clear correlation between Hpylori infection and the risk of gastric cancer; however, general eradication is not recommended as cancer prophylaxis and time points for treatment remain controversial in different areas of the world. Prevalence rates in Western countries are decreasing, especially in younger people (〈 10%); and a decline in distal gastric adenocarcinoma has been observed. Risk groups in Western countries still show considerably higher risk of developing cancer, especially in patients infected with cagA^+ strains and in persons harboring genetic polymorphism of the IL-1B promoter (-511T/T) and the corresponding IL-1 receptor antagonist (IL-1RN^*2). Thus, general eradication of all infected persons in Western countries not recommended and is limited to risk groups in order to achieve a risk reduction. In contrast, infection rates and cancer prevalence are still high in East Asian countries. A prevention strategy to treat infected persons may avoid the development of gastric cancer to a large extent and with enormous clinical importance. However, studies in China and Japan indicate that prevention of gastric cancer is effective only in those patients that do not display severe histological changes such as atrophy and intestinal metaplasia. Thus, prophylactic strategies to prevent gastric cancer in high risk populations such as China should therefore especially aim at individuals now at younger age when the histological alterations caused by the bacterial infection was still reversible. In countries with a low prevalence of gastric cancer, risk groups carrying cagA^+ strains and IL-1 genetic polymorphisms should be identified and treated.展开更多
AIM: To explore the anti-hepatitis B virus (HBV) effects of Boehmeria nivea (B. nivea) root extract (BNE) by using the HepG2 2.2.15 cell model system. METHODS: Hepatitis B surface antigen (HBsAg), hepatitis B virus e ...AIM: To explore the anti-hepatitis B virus (HBV) effects of Boehmeria nivea (B. nivea) root extract (BNE) by using the HepG2 2.2.15 cell model system. METHODS: Hepatitis B surface antigen (HBsAg), hepatitis B virus e antigen (HBeAg), and HBV DNA were measured by using ELISA and real-time PCR, respectively. Viral DNA replication and RNA expression were determined by using Southern and Northern blot, respectively. RESULTS: In HepG2 2.2.15 cells, HBeAg (60%, P < 0.01) and particle-associated HBV DNA (> 99%, P < 0.01) secretion into supernatant were significantly inhibited by BNE at a dose of 100 mg/L, whereas the HBsAg was not inhibited. With different doses of BNE, the reduced HBeAg was correlated with the inhibition of HBV DNA. The anti-HBV effect of BNE was not caused by its cytotoxicity to cells or inhibition of viral DNA replication and RNA expression. CONCLUSION: BNE could effectively reduce the HBV production and its anti-HBV machinery might differ from the nucleoside analogues.展开更多
AIM: To study the significance of serum anti-hepatitis E virus (HEV) IgA in patients with hepatitis E. METHODS: A new method was established to assay anti-HEY IgA, which could be detected in the middle phase of th...AIM: To study the significance of serum anti-hepatitis E virus (HEV) IgA in patients with hepatitis E. METHODS: A new method was established to assay anti-HEY IgA, which could be detected in the middle phase of the infection. We compared anti-HEV IgA assay with anti-HEV IgM and anti-HEV IgG assay in sera from 60 patients with positive HEV-RNA. RESULTS: The 60 patients with positive HEV-RNA had both anti-HEV IgA and anti-HEV IgM and 410 patients with negative HEV-RNA were used as control. Periodic serum samples obtained from 60 patients with hepatitis E were tested for HEV RNA, anti-HEV IgM, anti-HEV IgA and anti-HEV IgG. Their HEV-RNA was detectable in the serum until 20 ±11 d. We used anti-HEV IgM and anti-HEV IgA assay to detect HEV infection and positive results were found in 90 ± 15 d and 120 ±23 d respectively, the positive rate of anti-HEV IgA was higher than that of anti-HEV IgM and HEV-RNA (P 〈0.05). CONCLUSION: The duration of anti-HEV IgA in serum is longer than that of anti-HEV IgM, and anti-HEV IgA assay is a good method to detect HEV infection.展开更多
Genetic epidemiology researches such as twin studies, family-clustering of hepatitis B virus (HBV) infection studies and ethnic difference studies have provided the evidence that host genetic factors play an importa...Genetic epidemiology researches such as twin studies, family-clustering of hepatitis B virus (HBV) infection studies and ethnic difference studies have provided the evidence that host genetic factors play an important role in determining the outcome of HBV infection. The opening questions include which human genes are important in infection and how to find them. Though a number of studies have sought genetic associations between HBV infection/persistence and gene polymorphisms, the candidate gene-based approach is clearly inadequate to fully explain the genetic basis of the disease. With the advent of new genetic markers and automated genotyping, genetic mapping can be conducted extremely rapid. This approach has been successful in some infectious diseases. Linkage analysis can find host genes susceptible to HBV and is of great clinical importance.展开更多
Pb2+ and Cd2+ in leachate were adsorbed on clay-solidified grouting curtain for waste landfills with equilibrium experiment. The cation exchange capacity was determined with ammonium acetate. And the concentration of ...Pb2+ and Cd2+ in leachate were adsorbed on clay-solidified grouting curtain for waste landfills with equilibrium experiment. The cation exchange capacity was determined with ammonium acetate. And the concentration of heavy metal cations in leachate was determined with atomic absorption spectrophotometer. Their equilibrium isotherms were measured, and the experimental isotherm data were analyzed by using Freundlich and Langmuir models. The results show that the adsorption capacities of the heavy metal cations are closely related to the compositions of clay-solidified grouting curtain, and the maximum adsorption appears at the ratio of cement to clay of 2∶4 in the experimental conditions. At their maximum adsorption and pH 5.0, the adsorption capacities of Pb 2+ and Cd 2+ are 16.19mg/g and 1.21mg/g. The competitive adsorption coefficients indicate that the adsorption of clay-solidified grouting curtain for Pb2+ is stronger than that for Cd 2+ . The adsorption process conforms to Freundlich’s model with related coefficient higher than 0.996.展开更多
Acute and chronic hepatitis C virus (HCV) infection remains a serious health problem worldwide, however, there has been advancement in the treatment of HCV infection due to standard treatment using pegylated interfero...Acute and chronic hepatitis C virus (HCV) infection remains a serious health problem worldwide, however, there has been advancement in the treatment of HCV infection due to standard treatment using pegylated interferon and ribavirin. The literature indicates that therapy for HCV is becoming more individualized. In addition to considering genotype and viral RNA levels before treatment, achievement of an early virologic response (EVR) and a rapid virologic response (RVR) is now possible during therapy. Moreover, problem patients, such as non-responders, relapsers, HIV or HBV co- infected patients, patients with liver cirrhosis, and pre- or post-liver transplantation patients are an increasing fraction of the patients requiring treatment. This article reviews the literature regarding standard treatments and problem patients with acute and chronic HCV infection. It also includes discussion on contraindications and side effects of treatment with interferon and ribavirin, as well as new drug development.展开更多
AIM: To investigate the effect of probiotic bacterium, Clostridium butyricum MIYAIRI 588 strain (CBM) on the changes of the fecal flora in Helicobacter pylori (H pylon) treatment. METHODS: Thirty-five patients w...AIM: To investigate the effect of probiotic bacterium, Clostridium butyricum MIYAIRI 588 strain (CBM) on the changes of the fecal flora in Helicobacter pylori (H pylon) treatment. METHODS: Thirty-five patients with gastric or duodenal ulcers positive for H pylori were randomized either to 1 wk amoxicillin, clarithromycin, lansoprazole (Group 1) or to the same regimen supplemented with CBM 7 d ahead of the triple therapy (Group 2). Stool samples were collected before and 2, 4, 7, 15, and 22 d after the starting eradication therapy, and were examined intestinal flora. Patients were required to keep a diary record of their condition. RESULTS: Obligate anaerobes decreased significantly on d 2, 4, 8 and 15 in Group 1. On the other hand, they did not decrease significantly in Group 2. The Escherichia coli was dominant bacterium in Enterobacteriaceae, but that was replaced by other species such as Klebsiella and Enterobacter after eradication in Group 1. The change was suppressed in Group 2. Abdominal symptoms were less frequent in Group 2 than in Group 1. CONCLUSION: The combined use of CBM reduced the changes in the intestinal flora and decreased the incidence of gastrointestinal side effects.展开更多
Anti-hepatitis B virus(HBV)therapy leads to the emer- gence of mutant viral strains during the treatment of chronic hepatitis B with nucleos(t)ides analogues. The existence of HBV variants with primary antiviral resis...Anti-hepatitis B virus(HBV)therapy leads to the emer- gence of mutant viral strains during the treatment of chronic hepatitis B with nucleos(t)ides analogues. The existence of HBV variants with primary antiviral resistance may be important for treatment choice. We studied two patients with chronic HBV infection by sequencing the HBV polymerase gene.They had adefovir-and tenofovir-related mutations in the viral polymerase,although they had never been treated. These mutations were rtV214A/rtN238T in one patient and rtA194T in the other.Thus,mutations in untreated patients deserve cautious surveillance.These data indicate that mutations that can theoretically confer adefovir or tenofovir resistance may emerge in treatmentnaive patients.展开更多
AIM: To compare the one-day quadruple therapy with a standard 7-d triple therapy for H pylori eradication in a rural population of China. METHODS: A total of 396 patients with 13C-urea breath test positive for H pyl...AIM: To compare the one-day quadruple therapy with a standard 7-d triple therapy for H pylori eradication in a rural population of China. METHODS: A total of 396 patients with 13C-urea breath test positive for H pylori were assigned into two groups: 239 patients received one-day quadruple therapy (amoxicillin 2000 mg qid; metronidazole 500 mg qid; bismuth citrate 900 mg qid and lansoprazole 60 mg once daily) and 157 patients received 7-d standard triple therapy (amoxicillin 1000 mg bid; clarithromycin 500 mg bid and lansoprazole 30 mg bid). All the patients underwent a 13C-UBT to assess the eradication of Hpylori infection six weeks after treatment. RESULTS: Two hundred and twenty-nine patients completed the one-day therapy (95.8%) and 148 patients completed the 7-d therapy (94.2%). The oneday therapy eradicated H pylori infection in 64 patients (27.95%). In contrast, 103 patients (69.59%) were Hpylori negative after the 7-d therapy (P 〈 0.01). CONCLUSION: This pilot study suggests there is no beneficial effect of the one-day therapy in treatment ofHpylori infection compared with the 7-d standard therapy.展开更多
The pathogenesis of liver damage associated with chronic hepatitis C virus (HCV) infection is thought to be largely immunomediated. However, some frequent histoo pathological features, such as steatosis, suggest a d...The pathogenesis of liver damage associated with chronic hepatitis C virus (HCV) infection is thought to be largely immunomediated. However, some frequent histoo pathological features, such as steatosis, suggest a direct cytopathic effect of HCV. The direct responsibility of HCV in the pathogenesis of steatosis is shown by: (1) the association with HCV genotype 3 infection, suggesting that some viral sequences are involved in the intracellular aco cumulation of lipids; (2) the correlation between severity of steatosis and HCV replication levels; (3) association between response to treatment and disappearance of steatosis. Experimental studies have shown that the nuo cleocapsid protein of HCV (core protein) is capable and sufficient to induce lipid accumulation in hepatocytes. Moreover, the observation that chronic hepatitis C pao tients have reduced serum levels of ApoB suggests an interference with the very-low density lipoprotein (VLDL) assembly, although other mechanisms are possible. In patients with sustained virological response induced by antiviral therapy, such levels are normalized. Other obo servations suggest that the pathogenesis of steatosis in chronic hepatitis C is not solely due to HCV. The origin of the mild steatosis observed in most patients may be metabolic, since its severity correlates with body mass index and insulin resistance. Most studies have shown a correlation between presence and/or severity of steatosis and fibrosis stage, but it is unclear whether this effect is direct or mediated by the associated insulin resistance, increased susceptibility to apoptosis, or by inflammao tory cytokines. Finally, steatosis negatively influences the rate of response to antiviral treatment, as confirmed by large clinical trials. Management of steatosis in chronic hepatitis C requires knowledge of its pathogenesis and may involve both life-style changes and pharmacological interventions, although the latter remain largely experio mental.展开更多
文摘Amidst growing environmental protection intensity by the Chinese government, this paper investigates the effects of environmental regulation on China's industrial pollution treatment productivity and environmental TFP. By estimating China's pollution treatment productivity between 2001 and 2008 and analyzing environmental regulation intensity and the effects of the relevant factors and pollution treatment productivity using panel data, this paper discovers that (1) pollution treatment productivity contributed a significant share of about 40% to industrial environmental TFP during the investigation period; (2) environmental regulation may not necessarily cause adverse impacts on pollution treatment efficiency and productivity but demonstrates a U-shaped relationship: when the share of pollution treatment cost in industrial value-added is above the range of 3.8%-5.1%, environmental regulation is likely to promote pollution treatment productivity and thus environmental TFP Judging by the estimation result, enhancing environmental protection and expediting the development of ecological civilization are conducive to China "s economic transition towards an intensive, efficient, circular, and sustainable development pattern. China's current industrial development has the capacity to tolerate a rather demanding level of pollution treatment and management and China needs to further rely on energy conservation and the environmental production industries to promote the progress of pollution treatment technologies.
文摘In the article, status quo of oil pollution in China's offshore area was in- troduced, and the sources of oil pollution in the ocean were analyzed. Furthermore, the possible hazards of marine oil pollution were discussed and related countermea- sures were proposed, including implementation of laws and regulations, enhancing awareness of environment protection, improvement of pollution monitoring and early warning mechanism, physical treatment, chemical treatment and biological treatment. With economy development, the demand of oil is increasing accordingly. Hence, oil pollution has become an urgent issue to be solved for better exploration of oil and protection of marine environment.
基金Supported by National Key Technology R&D Program(No.2012BAD15B03)China CDM Fund(1213054)~~
文摘The research introduced pollution caused by animal farming on waters,agricultural lands,and atmosphere,as well as environment pollution and economic causes.Furthermore,a series of economic policies were proposed on preventing animal farming,such as definition of rights property,economic impetus and circular farming.
文摘Objective: To investigate treatment efficacy for persistent chlamydial infection in the urogenital tract. Methods: 207 patients with persistent chlamydial urogenital infection were treated with tetracycline,azithromycin, ofloxacin or a combination of these.Result: 47.92%-68.60% of patients with persistent chlamydial urogenital infection were cured depending on the drug used. Ofloxacin had better results than tetracycline and azithromycin.Conclusion: Many patients were resistant to treatment with tetracycline and azithromycin. Ofloxacin proved effective.
基金Supported by National Natural Science Foundation of China(Grant No.21067003,5136-4015)Natural Science Foundation of Jiangxi Province(Grant No.20114BAB203024)National High-Tech Research and Development Program of China(Grant No.2012BAC11B07)~~
文摘This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3:50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10:50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.
基金Supported by grant SFB535/A2 from DFG, EU QLK 2000- 01476 and DFG UR72/1-3, UR72/1-4
文摘Hepadnaviridae is a family of hepatotropic DNA viruses that is divided into the genera orthohepadnavirus of mammals and avihepadnavirus of birds. All members of this family can cause acute and chronic hepatic infection, which in the case of human hepatitis B virus (HBV) constitutes a major global health problem. Although our knowledge about the molecular biology of these highly liver-specific viruses has profoundly increased in the last two decades, the mechanisms of attachment and productive entrance into the differentiated host hepatocytes are still enigmatic. The difficulties in studying hepadnaviral entry were primarily caused by the lack of easily accessible in vitro infection systems. Thus, for more than twenty years, differentiated primary hepatocytes from the respective species were the only in vitro models for both orthohepadnaviruses (e.g. HBV) and avihepadnaviruses (e.g. duck hepatitis B virus [DHBV]). Two important discoveries have been made recently regarding HBV: (1) primary hepatoo/tes from tree-shrews; i.e., Tupaia belangeri, can be substituted for primary human hepatocytes, and (2) a human hepatoma cell line (HepaRG) was established that gains susceptibility for HBV infection upon induction of differentiation in vitro. A number of potential HBV receptor candidates have been described in the past, but none of them have been confirmed to function as a receptor. For DHBV and probably all other avian hepadnaviruses, carboxypeptidase D (CPD) has been shown to be indispensable for infection, although the exact role of this molecule is still under debate. While still restricted to the use of primary duck hepatocytes (PDH), investigations performed with DHBV provided important general concepts on the first steps of hepadnaviral infection. However, with emerging data obtained from the new HBV infection systems, the hope that DHBV utilizes the same mechanism as HBV only partially held true. Nevertheless, both HBV and DHBV in vitro infection systems will help to: (1) functionally dissect the hepadnaviral entry pathways, (2) perform reverse genetics (e.g. test the fitness of escape mutants), (3) titrate and map neutralizing antibodies, (4) improve current vaccines to combat acute and chronic infections of hepatitis B, and (5) develop entry inhibitors for future clinical applications.
文摘AIM: TO define the potential role of programmed death-i/programmed death-ligand (PD-1/PD-L) pathway in different hepatitis B virus (HBV) infection disease status; we examined the expression of PD-1 on antigen specific CD8+T cells in peripheral blood of patients with chronic hepatitis B (CriB) and acute exacerbation of hepatitis B (AEHB) infection. METHODS: The PD-1 level on CD8+ T lymphocytes and the number of HBV specific CD8+ T lymphocytes in patients and healthy controls (HCs) were analyzed by staining with pentameric peptide-human leukocyte antigen2 (HLA2) complexes combined with flow cytometry. Real-time quantitative polymerase chain reaction (PCR) was used to measure the serum HBV- DNA levels. RESULTS: The level of PD-1 expression on total CD8+ T cells in CHB patients (13.86% ± 3.38%) was significantly higher than that in AEHB patients (6.80%± 2.19%, P 〈 0.01) and healthy individuals (4.63% ± 1.23%, P 〈 0.01). Compared to AEHB patients (0.81% ± 0.73%), lower frequency of HBV-specific CD8+ T cells was detected in chronic hepatitis B patients (0.37% ± 0.43%, P 〈 0.05). There was an inverse correlation between the strength of HBV-specific CD8+ T-cell response and the level of PD-1 expression. Besides, there was a significant positive correlation between HBV viral load and the percentage of PD-1 expression on CD8+ T cells in CriB and AEHB subjects (R = 0.541, P 〈 0.01). However, PD-1 expression was not associated with disease flare-ups as indicated by alanine aminotransferase (ALT) levels (R = 0.066, P 〉 0.05). CONCLUSION: Our results confirm previous reports that HBV specific CD8+T-cell response in the peripheral blood is more intense in patients with AEHB than in chronic hepatitis B wlth persistent viral infection. Moreover, there is a negative correlation between the level of PD-1 and the intensity of virus specific CD8+ T cell response.
基金Supported by Deutsche Forschungsgemeinschaft (DFGGraduiertenkolleg 333: Biology of Human Diseases) and by agrant from the DFG to C.P. (Pr 411/9-1) and the Dr. Else Kr nerFresenius Stiftung
文摘Infection with H pylori leads to a persistent chronic inflammation of the gastric mucosa, thereby increasing the risk of distal gastric adenocarcinoma. Numerous studies have determined a clear correlation between Hpylori infection and the risk of gastric cancer; however, general eradication is not recommended as cancer prophylaxis and time points for treatment remain controversial in different areas of the world. Prevalence rates in Western countries are decreasing, especially in younger people (〈 10%); and a decline in distal gastric adenocarcinoma has been observed. Risk groups in Western countries still show considerably higher risk of developing cancer, especially in patients infected with cagA^+ strains and in persons harboring genetic polymorphism of the IL-1B promoter (-511T/T) and the corresponding IL-1 receptor antagonist (IL-1RN^*2). Thus, general eradication of all infected persons in Western countries not recommended and is limited to risk groups in order to achieve a risk reduction. In contrast, infection rates and cancer prevalence are still high in East Asian countries. A prevention strategy to treat infected persons may avoid the development of gastric cancer to a large extent and with enormous clinical importance. However, studies in China and Japan indicate that prevention of gastric cancer is effective only in those patients that do not display severe histological changes such as atrophy and intestinal metaplasia. Thus, prophylactic strategies to prevent gastric cancer in high risk populations such as China should therefore especially aim at individuals now at younger age when the histological alterations caused by the bacterial infection was still reversible. In countries with a low prevalence of gastric cancer, risk groups carrying cagA^+ strains and IL-1 genetic polymorphisms should be identified and treated.
文摘AIM: To explore the anti-hepatitis B virus (HBV) effects of Boehmeria nivea (B. nivea) root extract (BNE) by using the HepG2 2.2.15 cell model system. METHODS: Hepatitis B surface antigen (HBsAg), hepatitis B virus e antigen (HBeAg), and HBV DNA were measured by using ELISA and real-time PCR, respectively. Viral DNA replication and RNA expression were determined by using Southern and Northern blot, respectively. RESULTS: In HepG2 2.2.15 cells, HBeAg (60%, P < 0.01) and particle-associated HBV DNA (> 99%, P < 0.01) secretion into supernatant were significantly inhibited by BNE at a dose of 100 mg/L, whereas the HBsAg was not inhibited. With different doses of BNE, the reduced HBeAg was correlated with the inhibition of HBV DNA. The anti-HBV effect of BNE was not caused by its cytotoxicity to cells or inhibition of viral DNA replication and RNA expression. CONCLUSION: BNE could effectively reduce the HBV production and its anti-HBV machinery might differ from the nucleoside analogues.
文摘AIM: To study the significance of serum anti-hepatitis E virus (HEV) IgA in patients with hepatitis E. METHODS: A new method was established to assay anti-HEY IgA, which could be detected in the middle phase of the infection. We compared anti-HEV IgA assay with anti-HEV IgM and anti-HEV IgG assay in sera from 60 patients with positive HEV-RNA. RESULTS: The 60 patients with positive HEV-RNA had both anti-HEV IgA and anti-HEV IgM and 410 patients with negative HEV-RNA were used as control. Periodic serum samples obtained from 60 patients with hepatitis E were tested for HEV RNA, anti-HEV IgM, anti-HEV IgA and anti-HEV IgG. Their HEV-RNA was detectable in the serum until 20 ±11 d. We used anti-HEV IgM and anti-HEV IgA assay to detect HEV infection and positive results were found in 90 ± 15 d and 120 ±23 d respectively, the positive rate of anti-HEV IgA was higher than that of anti-HEV IgM and HEV-RNA (P 〈0.05). CONCLUSION: The duration of anti-HEV IgA in serum is longer than that of anti-HEV IgM, and anti-HEV IgA assay is a good method to detect HEV infection.
基金Supported by the National Natural Science Foundation of China, No. 30230210
文摘Genetic epidemiology researches such as twin studies, family-clustering of hepatitis B virus (HBV) infection studies and ethnic difference studies have provided the evidence that host genetic factors play an important role in determining the outcome of HBV infection. The opening questions include which human genes are important in infection and how to find them. Though a number of studies have sought genetic associations between HBV infection/persistence and gene polymorphisms, the candidate gene-based approach is clearly inadequate to fully explain the genetic basis of the disease. With the advent of new genetic markers and automated genotyping, genetic mapping can be conducted extremely rapid. This approach has been successful in some infectious diseases. Linkage analysis can find host genes susceptible to HBV and is of great clinical importance.
基金Project (200065) supported by University Key Teacher Foundation of the Ministry of Education of China
文摘Pb2+ and Cd2+ in leachate were adsorbed on clay-solidified grouting curtain for waste landfills with equilibrium experiment. The cation exchange capacity was determined with ammonium acetate. And the concentration of heavy metal cations in leachate was determined with atomic absorption spectrophotometer. Their equilibrium isotherms were measured, and the experimental isotherm data were analyzed by using Freundlich and Langmuir models. The results show that the adsorption capacities of the heavy metal cations are closely related to the compositions of clay-solidified grouting curtain, and the maximum adsorption appears at the ratio of cement to clay of 2∶4 in the experimental conditions. At their maximum adsorption and pH 5.0, the adsorption capacities of Pb 2+ and Cd 2+ are 16.19mg/g and 1.21mg/g. The competitive adsorption coefficients indicate that the adsorption of clay-solidified grouting curtain for Pb2+ is stronger than that for Cd 2+ . The adsorption process conforms to Freundlich’s model with related coefficient higher than 0.996.
文摘Acute and chronic hepatitis C virus (HCV) infection remains a serious health problem worldwide, however, there has been advancement in the treatment of HCV infection due to standard treatment using pegylated interferon and ribavirin. The literature indicates that therapy for HCV is becoming more individualized. In addition to considering genotype and viral RNA levels before treatment, achievement of an early virologic response (EVR) and a rapid virologic response (RVR) is now possible during therapy. Moreover, problem patients, such as non-responders, relapsers, HIV or HBV co- infected patients, patients with liver cirrhosis, and pre- or post-liver transplantation patients are an increasing fraction of the patients requiring treatment. This article reviews the literature regarding standard treatments and problem patients with acute and chronic HCV infection. It also includes discussion on contraindications and side effects of treatment with interferon and ribavirin, as well as new drug development.
文摘AIM: To investigate the effect of probiotic bacterium, Clostridium butyricum MIYAIRI 588 strain (CBM) on the changes of the fecal flora in Helicobacter pylori (H pylon) treatment. METHODS: Thirty-five patients with gastric or duodenal ulcers positive for H pylori were randomized either to 1 wk amoxicillin, clarithromycin, lansoprazole (Group 1) or to the same regimen supplemented with CBM 7 d ahead of the triple therapy (Group 2). Stool samples were collected before and 2, 4, 7, 15, and 22 d after the starting eradication therapy, and were examined intestinal flora. Patients were required to keep a diary record of their condition. RESULTS: Obligate anaerobes decreased significantly on d 2, 4, 8 and 15 in Group 1. On the other hand, they did not decrease significantly in Group 2. The Escherichia coli was dominant bacterium in Enterobacteriaceae, but that was replaced by other species such as Klebsiella and Enterobacter after eradication in Group 1. The change was suppressed in Group 2. Abdominal symptoms were less frequent in Group 2 than in Group 1. CONCLUSION: The combined use of CBM reduced the changes in the intestinal flora and decreased the incidence of gastrointestinal side effects.
基金Supported by Siemens Medical Solutions Diagnostics,France,provided the reagents
文摘Anti-hepatitis B virus(HBV)therapy leads to the emer- gence of mutant viral strains during the treatment of chronic hepatitis B with nucleos(t)ides analogues. The existence of HBV variants with primary antiviral resistance may be important for treatment choice. We studied two patients with chronic HBV infection by sequencing the HBV polymerase gene.They had adefovir-and tenofovir-related mutations in the viral polymerase,although they had never been treated. These mutations were rtV214A/rtN238T in one patient and rtA194T in the other.Thus,mutations in untreated patients deserve cautious surveillance.These data indicate that mutations that can theoretically confer adefovir or tenofovir resistance may emerge in treatmentnaive patients.
基金Supported by a grant from International Digestive Cancer Alliance and Peking University School of Oncology
文摘AIM: To compare the one-day quadruple therapy with a standard 7-d triple therapy for H pylori eradication in a rural population of China. METHODS: A total of 396 patients with 13C-urea breath test positive for H pylori were assigned into two groups: 239 patients received one-day quadruple therapy (amoxicillin 2000 mg qid; metronidazole 500 mg qid; bismuth citrate 900 mg qid and lansoprazole 60 mg once daily) and 157 patients received 7-d standard triple therapy (amoxicillin 1000 mg bid; clarithromycin 500 mg bid and lansoprazole 30 mg bid). All the patients underwent a 13C-UBT to assess the eradication of Hpylori infection six weeks after treatment. RESULTS: Two hundred and twenty-nine patients completed the one-day therapy (95.8%) and 148 patients completed the 7-d therapy (94.2%). The oneday therapy eradicated H pylori infection in 64 patients (27.95%). In contrast, 103 patients (69.59%) were Hpylori negative after the 7-d therapy (P 〈 0.01). CONCLUSION: This pilot study suggests there is no beneficial effect of the one-day therapy in treatment ofHpylori infection compared with the 7-d standard therapy.
基金Supported by the Swiss National Science Foundation grant, No. 3200B0-103727/1
文摘The pathogenesis of liver damage associated with chronic hepatitis C virus (HCV) infection is thought to be largely immunomediated. However, some frequent histoo pathological features, such as steatosis, suggest a direct cytopathic effect of HCV. The direct responsibility of HCV in the pathogenesis of steatosis is shown by: (1) the association with HCV genotype 3 infection, suggesting that some viral sequences are involved in the intracellular aco cumulation of lipids; (2) the correlation between severity of steatosis and HCV replication levels; (3) association between response to treatment and disappearance of steatosis. Experimental studies have shown that the nuo cleocapsid protein of HCV (core protein) is capable and sufficient to induce lipid accumulation in hepatocytes. Moreover, the observation that chronic hepatitis C pao tients have reduced serum levels of ApoB suggests an interference with the very-low density lipoprotein (VLDL) assembly, although other mechanisms are possible. In patients with sustained virological response induced by antiviral therapy, such levels are normalized. Other obo servations suggest that the pathogenesis of steatosis in chronic hepatitis C is not solely due to HCV. The origin of the mild steatosis observed in most patients may be metabolic, since its severity correlates with body mass index and insulin resistance. Most studies have shown a correlation between presence and/or severity of steatosis and fibrosis stage, but it is unclear whether this effect is direct or mediated by the associated insulin resistance, increased susceptibility to apoptosis, or by inflammao tory cytokines. Finally, steatosis negatively influences the rate of response to antiviral treatment, as confirmed by large clinical trials. Management of steatosis in chronic hepatitis C requires knowledge of its pathogenesis and may involve both life-style changes and pharmacological interventions, although the latter remain largely experio mental.