Enhanced sequestration of molybdenum(VI) using composite constructed wetlands and responses of microbial communities

The molybdenum (Mo) non-point source pollution in the mining area has an irreversible impact on the surrounding water and soil ecosystems. Herein, three integrated vertical subsurface flow constructed wetlands (CWs) were constructed to assess the effects of combination substrates and plant on the removal of Mo(VI). Results showed that CW1 with combination substrates and cattail exhibited a favorable removal performance for Mo(VI) at 80.90%. Moreover, most Mo(VI) retained in the CWs was retained in the substrate (58.13-88.04%), and the largest fraction of Mo(VI) retained was the water-soluble fraction on the surface of the combination substrates. Mo(VI) removal was also influenced by the microbial community composition in substrate, especially their co-occurrence networks. The species that showed significant positive correlation with Mo(VI) removal were Planctomycetes, Latescibacteria, Armatimonadetes, and Gemmatimonadetes. Moreover, CWs added plants showed that more co-occurrences interaction between taxa occurs, which means that the wetlands efficiently select recruitment of potential microbial consortia and change the co-occurrences to remove pollution in the substrate. These results could be useful in providing an ecology-based solution for the treatment of Mo(VI) in wastewater, especially in adjusting the microbial communities for Mo(VI) removal at the genetic level.

Recent and frequent insertions of chloroplast DNA into maize nuclear chromosomes

Organellar DNA transfer into the nucleus and incorporation into chromosomes are continuing processes. We have examined chloroplast DNA insertions in maize chromosomes using fluorescence in situ hybridization (FISH). Probes to detect the nuclear-plastid sequences (NUPTs) were generated using 14 overlapping fragments of the chloroplast genome. Using current FISH methods, detection of NUPTs on mitotic metaphase chromosomes requires relatively large insertions (>3 kb) with strong sequence similarity to chloroplast DNA. In the B73 inbred line, hybridization of each fragment separately resolved a total of 49 NUPT sites; fewer sites (30) were detectable when all the probes were combined. The combined set of probes was hybridized to 10 genetically useful maize inbred lines and identified 19-30 NUPTs in each line. In all but two of the lines, a prominent NUPT was present on the long arm of chromosome 5. Collectively, the number of NUPTs exceeds the number of nuclear-mitochondrial (NUMT) sites identified within the same set of inbred lines. A majority of the NUPTs are found at sites that are different from the NUMTs. Like NUMTs, the positions of the NUPTs vary greatly among the lines, suggesting that the transfers are recent as well as frequent. Thus, insertions of large segments of chloroplast and mitochondrial DNA are components of the dynamic fraction of maize nuclear genomes.

Metabolic and histological features of non-alcoholic fatty liver disease patients with different serum alanine aminotransferase levels

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in affluent countries. Serum alanine aminotransferase (ALT) level is commonly performed to monitor NAFLD patients, but its clinical relevance is unclear.

AIM

To evaluate the metabolic and histological features of NAFLD patients with different ALT levels.

METHODS

A total of 173 consecutive patients with biopsy-proven NAFLD were studied. Patients with persistently normal ALT and those with abnormal ALT were compared.

RESULTS

Patients with persistently normal ALT had lower steatosis grade than patients with abnormal ALT, but they had similar degree of lobular inflammation, ballooning and fibrosis. Among 19 patients with ALT below 0.5 times the upper limit of normal (ULN) at the time of liver biopsies, 8 (42%) and 3 (16%) had steatohepatitis and significant fibrosis respectively. The within-patient coefficient of variance was similarly high in patients with simple steatosis and steatohepatitis (33.5). Age and glucose, but not ALT, were independent factors associated with significant fibrosis.

DISCUSSION

Metabolic factors, but not ALT, are associated with histological severity. Patients with ALT < 0.5 x ULN may still have non-alcoholic steatohepatitis (NASH) and significant fibrosis. Evaluation of NAFLD patients should be based on metabolic risk factors, but not ALT level.

Prevalence of undiagnosed diabetes and postchallenge hyperglycaemia in Chinese patients with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease is prevalent in affluent countries and is strongly associated with metabolic syndrome.

AIM

To study the prevalence of undiagnosed diabetes and postchallenge hyperglycaemia in Chinese patients with non-alcoholic fatty liver disease.

METHODS

73 consecutive patients with biopsy-proven non-alcoholic fatty liver disease and no history of diabetes underwent comprehensive metabolic screening. Diagnosis of diabetes and impaired glucose regulation was based on the 2006 American Diabetes Association criteria.

RESULTS

The prevalence of undiagnosed diabetes and impaired glucose tolerance in non-alcoholic fatty liver disease patients was 33% and 29%, respectively. Among patients with 2-h plasma glucose above 7.8 mm, 47% had normal fasting glucose (below 5.6 mm). Impaired glucose tolerance was more common in patients with non-alcoholic steatohepatitis than those with simple hepatic steatosis (P = 0.036), and 2-h plasma glucose correlated with fibrosis stage (Spearman coefficient: 0.25, P = 0.046). In a binary logistic regression analysis, high fasting glucose and low high-density lipoprotein cholesterol were independent factors associated with diabetes. Nevertheless, if oral glucose tolerance test was only performed in non-alcoholic fatty liver disease patients with impaired fasting glucose, 20.8% of diabetes cases would be missed.

CONCLUSIONS

Isolated postchallenge hyperglycaemia is common among Chinese non-alcoholic fatty liver disease patients without history of diabetes. It is associated with histological severe disease, and cannot be accurately predicted by any fasting glucose cut-off.

Genetic polymorphisms of interleukin-1-beta in association with sustained response to anti-viral treatment in chronic hepatitis B in Chinese

BACKGROUND

Interleukin-1beta is a pro-inflammatory cytokine that may influence host defence against viral infection.

AIM

To investigate the impact of interleukin-1beta gene polymorphism on the response to anti-viral treatment.

METHOD

Hepatitis B e antigen-positive chronic hepatitis B patients who have completed a randomized study of peginterferon alpha-2b and lamivudine combination vs. lamivudine monotherapy were included. Sustained responders were patients who had persistent hepatitis B e antigen loss and less than two occasions with hepatitis B virus DNA >100 000 copies/mL at any time up to week 76 post-treatment. Polymorphisms at interleukin-1beta-511, -31 and -3954 and interleukin-1 receptor antagonist (RN) were studied.

RESULTS

Eighty-eight patients were studied and 18 (20%) patients developed sustained response. Near complete linkage disequilibrium was observed between interleukin-1beta-511 and -31 loci. After adjustment for the potential confounding effects of treatment allocation, hepatitis B virus genotype, pre-treatment alanine aminotransferase and hepatitis B virus DNA levels, genotype C/T at interleukin-1beta-511 was found to be associated with higher sustained response than genotype C/C (adjusted odds ratio 10.4, 95% CI 1.1, 96.9, P = 0.040). The proportion of sustained responders tend to be higher among patients with allele T at interleukin-1beta-511 (83%) than those without (70%) (P = 0.058).

CONCLUSION

High interleukin-1beta production genotype at position -511 has a favourable response to anti-viral treatments.

Systematic review: treatment of chronic hepatitis B virus infection by pegylated interferon

BACKGROUND

Pegylated interferon-alpha has been shown to be more efficacious than conventional interferon in treating chronic hepatitis C. The use of peginterferon in chronic hepatitis B virus infection with positive hepatitis B e antigen has also been tested in a number of trials since 2003.

AIM

To systematically summarize and compare the results of these studies.

METHODS

Four studies were identified from PubMed, Medline and reference lists. Data from the trials were extracted and analysed. Where appropriate, combined odds ratio of different trials was calculated. Safety data including serious adverse events and emergence of drug-resistant mutants were recorded.

RESULTS

Three of the four trials contained predominantly Asian patients. Peginterferon is found to be superior to lamivudine monotherapy and induced sustained biochemical and virological responses in about one-thirds of patients after 12 months of therapy. Coadministration of lamivudine did not result in improvement in viral suppression. Peginterferon appears to reduce the emergence of YMDD mutation in the combination treatment groups. It was well tolerated with serious adverse events reported in <10% of patients in most trials.

CONCLUSIONS

Peginterferon-alpha treatment of at least 6 months should be considered as one of the first-line therapeutic options for hepatitis B virus infection.

Anti-proliferative and pro-apoptotic effects of herbal medicine on hepatic stellate cell

Hepatic stellate cells (HSC) play a central role in hepatic fibrosis and compounds that promote apoptosis in HSC may have anti-fibrotic potentials. Herbal medicine has long been used in chronic liver disease but there is little scientific evidence for their actions. The present study investigated the effects of 14 commonly used herbs on cellular proliferation and apoptosis of a rat hepatic stellate cell line, HSC-T6 and the underlying mechanism of herb-induced apoptosis. HSC-T6 cell were incubated with herbal extracts and their proliferation was assessed by colorimetric assay. Apoptosis was measured and confirmed by flow cytometry, terminal transferase uridyl nick end labeling (TUNEL) assay and morphological features in hematoxylin and eosin staining. Apoptotic pathways involving Fas receptor and Bcl-2 family were investigated by Western blot. Five herbs, namely Angelica sinensis (AS), Carthamus tinctorius (CT), Ligusticum chuanxiong (LC), Salvia miltiorrhiza (SM) and Stephania tetrandra (ST) demonstrated both anti-proliferative and pro-apoptotic activities in HSC-T6. The highest potency was detected in SM and ST with 51.63 and 44.52% of HSC-T6 showing apoptotic changes, respectively. This was associated with upregulation of Fas and Bax and down-regulation of Bcl-xL in HSC. Fas ligand and Bcl2 expressions remained unchanged. The potential anti-fibrotic effect of herbal medicine warrants further evaluation.

Complications of liver donation for living related liver transplantation

Living related liver transplantation (LRLT) has gained popularity, especially in Asian countries as the primary mode of liver transplantation. LRLT, however, carries the inherent problem of potential donor harm. In view of reports of donor deaths and significant donor morbidity (as high as 67%), we examined donor complication rates in our LRLT program. All sixteen LRLT donors between February 2000 and January 2003 were retrospectively analyzed. The 16 donors (13 men, 3 women) of mean age 30 years (range, 18-49 years) included 5 donations from siblings, 2 from parents, and 9 from offsprings. The portion of liver donated was L hepatectomy (n = 4) R hepatectomy (n = 7), and Modified Extended R hepatectomy (n = 5) with the weight of resected liver being 618.9 g (range, 380-1000). The mean blood loss was 936 mL (range, 400-1900 mL), but only 2 donors required transfusion of banked blood. The mean intensive care unitstay was 1.06 days (range, 1-2 days) and the mean hospital stay was 9.12 days (range, 7-14 days). There was no case of reoperation and no mortality. There was no biliary or vascular complication. Four of 16 (25%) donors had a minor morbidity; 2 of 16 (12.5%) had a morbidity requiring intervention. In conclusion, with meticulous preoperative, intraoperative, and postoperative management, successful LRLT can be performed with minimal donor morbidities.

Impact of severe acute respiratory syndrome on liver transplantation service

Severe acute respiratory syndrome (SARS) struck 1755 patients in Hong Kong and developed into a global health crisis. Although the World Health Organization and national health authorities are sparing no effort to contain the disease and to find a cure for the potentially deadly infection, SARS has an impact on our liver transplantation (LTx) program. Before the SARS outbreak, an average of 1 LTx was performed per month in our center. For 6 months since the outbreak, there had been no LTx performed. The intensive care unit had to be dedicated to patients with SARS. Two of the LTx team members were struck by SARS. A survey conducted among LTx recipients and their family members (n = 45) demonstrated symptoms of anxiety and stress in all. Some LTx recipients were treated at the Emergency Department for suspected SARS, which were later confirmed to be false alarms. Many LTx patients were too frightened to come back for follow-up. A new strain of coronavirus was identified as the causative agent. The origin of this virus is uncertain but the probability of zoonoses is being seriously discussed. Not only are immunosuppressed patients exposed to higher risk of infection, but also the waiting list mortality is also expected to increase. The SARS outbreak has demonstrated the vulnerability of an organ transplantation service and reminds us of the fearful possibility of zoonoses in future xeno-transplantation.

Histological progression of non-alcoholic fatty liver disease in Chinese patients

BACKGROUND

Non-alcoholic fatty liver disease is an important cause of chronic hepatitis and cryptogenic cirrhosis. The natural history of non-alcoholic fatty liver disease is not well understood especially in Asian populations.

AIM

To investigate the histological progression in Chinese patients with biopsy-proven non-alcoholic fatty liver disease.

METHODS

Chinese patients who had liver biopsy at least 3 years ago and confirmed to have non-alcoholic fatty liver disease were invited for a second liver biopsy. Clinical and laboratory parameters related to their liver function and metabolic syndrome were recorded and analysed. Liver biopsies were scored for the degree of steatosis, necroinflammation and fibrosis. Correlation coefficients were calculated to assess the association between changes in histological scores and metabolic parameters.

RESULTS

Seventeen patients who had been followed up for a median period of 6.1 (range: 3.8-8.0) years underwent a second liver biopsy. Nine (53%) patients had progressive disease with worsening of fibrosis score. No statistically significant correlation was found between the changes in histological scores and metabolic parameters. Seven patients developed hypertension or diabetes mellitus during the period of follow-up.

CONCLUSIONS

Non-alcoholic fatty liver disease is a progressive disease in Chinese patients as in their Caucasian counterparts. Diagnosis of non-alcoholic fatty liver disease may predate development of new components of metabolic syndrome.

Human hepatic stellate cell lines, LX-1 and LX-2: new tools for analysis of hepatic fibrosis

BACKGROUND

Hepatic stellate cells (HSCs) are a major fibrogenic cell type that contributes to collagen accumulation during chronic liver disease. With increasing interest in developing antifibrotic therapies, there is a need for cell lines that preserve the in vivo phenotype of human HSCs to elucidate pathways of human hepatic fibrosis. We established and characterised two human HSC cell lines termed LX-1 and LX-2, and compared their features with those of primary human stellate cells.

METHODS AND RESULTS

LX-1 and LX-2 were generated by either SV40 T antigen immortalisation (LX-1) or spontaneous immortalisation in low serum conditions (LX-2). Both lines express alpha smooth muscle actin, vimentin, and glial fibrillary acid protein, as visualised by immunocytochemistry. Similar to primary HSCs, both lines express key receptors regulating hepatic fibrosis, including platelet derived growth factor receptor beta (betaPDGF-R), obese receptor long form (Ob-RL), and discoidin domain receptor 2 (DDR2), and also proteins involved in matrix remodelling; matrix metalloproteinase (MMP)-2, tissue inhibitor of matrix metalloproteinase (TIMP)-2, and MT1-MMP, as determined by western analyses. LX-2 have reduced expression of TIMP-1. LX-2, but not LX-1, proliferate in response to PDGF. Both lines express mRNAs for alpha1(I) procollagen and HSP47. Transforming growth factor beta1 stimulation increased their alpha1(I) procollagen mRNA expression, as determined by quantitative reverse transcription-polymerase chain reaction. LX-2, but not LX-1, cells are highly transfectable. Both lines had a retinoid phenotype typical of stellate cells. Microarray analyses showed strong similarity in gene expression between primary HSCs and either LX-1 (98.4%) or LX-2 (98.7%), with expression of multiple neuronal genes.

CONCLUSIONS

LX-1 and LX-2 human HSC lines provide valuable new tools in the study of liver disease. Both lines retain key features of HSCs. Two unique advantages of LX-2 are their viability in serum free media and high transfectability.

Absence of impact of donor hepatic steatosis and posttransplantation lamivudine resistance in a patient with chronic hepatitis B

A patient with chronic hepatitis B underwent liver transplantation for end-stage cirrhosis. The donor liver graft had moderate steatosis and fibrosis. He was placed on lamivudine for hepatitis B prophylaxis but developed viral relapse due to emergence of a lamivudine-resistant mutant at week 72 posttransplantation. Results of liver biochemistry were normal liver histology revealed minimal steatosis and inflammation at weeks 151 and 128, respectively. This report illustrates that the use of a steatotic donor liver and the emergence of lamivudine resistance posttransplantation are not necessarily associated with significant graft damage. A marginal donor graft can be considered due to the donor shortage. Lamivudine monoprophylaxis for hepatitis B virus-related liver diseases post liver transplantation can be used in areas where hepatitis B immunoglobulin is not affordable.

Genotype C hepatitis B virus infection is associated with an increased risk of hepatocellular carcinoma

BACKGROUND

Identification of risk factors for the development of hepatocellular carcinoma (HCC) is important for HCC surveillance in chronic hepatitis B virus (HBV) infection. Our aim was to study the independent risk factors and effect of HBV genotypes on HCC development in a prospective longitudinal cohort of chronic hepatitis B patients.

PATIENTS AND METHODS

Chronic hepatitis B patients recruited since 1997 were prospectively followed up for the development of HCC. HCC was diagnosed by a combination of alpha fetoprotein, imaging, and histology. Liver cirrhosis was defined as ultrasonic features of cirrhosis together with hypersplenism, ascites, varices, and/or encephalopathy.

RESULTS

In total, 426 patients were followed up for 1664 person years; median 225 (range 12-295) weeks. Forty nine (11%) patients had underlying clinical liver cirrhosis. A total of 242 (57%) and 179 (42%) patients had HBV genotypes C and B, respectively. Twenty five patients developed HCC in a median follow up of 121 (range 14-236) weeks. The overall incidence of HCC was 1502 cases per 100 000 person years. On multivariate analysis, clinical liver cirrhosis and HBV genotype C infection were independently associated with HCC development, with an adjusted relative risk of 10.24 (95% confidence interval (CI) 4.39-23.89; p<0.001) and 2.84 (95% CI 1.05-7.72; p = 0.040), respectively. Patient age, sex, hepatitis B e antigen (HBeAg) status, alanine aminotransferase (ALT) levels, and basal core promoter mutations did not predict HCC development. Patients infected with HBV genotype C tended to have persistently positive HBeAg or fluctuating HBeAg status and higher ALT levels during the follow up period.

CONCLUSION

Genotype C HBV infection is an independent risk factor for HCC development in addition to liver cirrhosis.

Clinical and histological features of non-alcoholic fatty liver disease in Hong Kong Chinese

BACKGROUND

Non-alcoholic fatty liver disease is prevalent in affluent countries and is a cause of cirrhosis and possibly hepatocellular carcinoma.

AIM

To examine the clinical and histological features of biopsy-proven non-alcoholic fatty liver disease and investigate the predictors of severe histological disease in Chinese patients.

METHODS

Electronic records of all patients (n = 247) who underwent liver biopsy between 1996 and 2003 in our hospital were retrieved. Patients who had histological features of non-alcoholic fatty liver disease were identified. The demographic, clinical, laboratory and histological (Brunt's criteria) parameters of these patients were analysed.

RESULTS

Forty-two patients had histology-proven non-alcoholic fatty liver disease. The median age was 47 years (range 23-69). All except one patient had features of metabolic syndrome. The median alanine aminotransferase was 93 (range 24-270) IU/L. Thirty-six (85.7%) patients had steatohepatitis and 11 (26.1%) also had fibrosis. Only one patient had stage 3 fibrosis. The presence of diabetes mellitus predicted higher grade steatohepatitis and fibrosis (P = 0.019) whereas alanine aminotransferase level had no correlation with histological severity of steatohepatitis. After a median follow-up of 42 months, no patient developed hepatic decompensation.

CONCLUSIONS

Most Chinese patients with non-alcoholic fatty liver disease had features of the metabolic syndrome. Histological activity was generally mild. Diabetes mellitus was the most important predictor of severe histological disease.

Double-blinded placebo-controlled study of Phyllanthus urinaris for the treatment of chronic hepatitis B

BACKGROUND

Previous studies suggested that Phyllanthus species have an anti-viral effect on hepatitis B, but methodologies have been inadequate.

AIMS

This study aimed to investigate the anti-viral effect of Phyllanthus urinaris.

METHODS

Chronic hepatitis B patients with positive hepatitis B e-antigen (HBeAg), hepatitis B virus (HBV) DNA > 500 000 copies/mL and elevated alanine transaminase (ALT) were recruited. Patients were randomized into groups of 12 receiving P. urinaris 1, 2 and 3 g three times daily for 6 months or placebo (six cases). The primary endpoint was HBV DNA reduction, and secondary endpoints were HBeAg seroconversion and ALT normalization.

RESULTS

On an intention-to-treat analysis there was no difference in log10[HBV DNA] reduction of the Phyllanthus 1-g (0.18 +/- 1.42), 2-g (0.33 +/- 1.08) and 3-g (0.85 +/- 1.30) groups vs. placebo (0.28 +/- 0.85) (P = 0.90, 0.92 and 0.38, respectively) at the end of treatment. The percentage of patients among the placebo, Phyllanthus 1-g, 2-g and 3-g groups undergoing HBeAg seroconversion (0%, 9.1%, 8.3% and 16.7%, respectively) and ALT normalization (0%, 0%, 8.3% and 33.3%) were not significantly different at the end of treatment. No delayed virological or biochemical response was documented at 24 weeks after the cessation of treatment. No serious adverse event was reported.

CONCLUSION

P. urinaris treatment for 6 months has no demonstrable anti-viral effect in chronic hepatitis B.