HCV-Mediated Apoptosis of Hepatocytes in Culture and Viral Pathogenesis

Chronic Hepatitis C Virus (HCV) infection is associated with progressive liver injury and subsequent development of fibrosis and cirrhosis. The death of hepatocytes results in the release of cytokines that induce inflammatory and fibrotic responses. The mechanism of liver damage is still under investigation but both apoptosis and immune-mediated processes may play roles. By observing the changes in gene expression patterns in HCV-infected cells, both markers and the causes of HCV-associated liver injury may be elucidated. HCV genotype 1b virus from persistently infected VeroE6 cells induced a strong cytopathic effect when used to infect Huh7.5 hepatoma cells. To determine if this cytopathic effect was a result of apoptosis, ultrastructural changes were observed by electron microscopy and markers of programmed cell death were surveyed. Screening of a human PCR array demonstrated a gene expression profile that contained upregulated markers of apoptosis, including tumor necrosis factor, caspases and caspase activators, Fas, Bcl2-interacting killer (BIK) and tumor suppressor protein, p53, as a result of HCV genotype 1b infection. The genes identified in this study should provide new insights into understanding viral pathogenesis in liver cells and may possibly help to identify novel antiviral and antifibrotic targets.

Measurement of serum 7α-hydroxy-4-cholesten-3-one as a marker of bile acid malabsorption in dogs with chronic diarrhoea: a pilot study

Bile acid malabsorption is a common cause of chronic diarrhoea in people, however it has never previously been investigated in dogs, despite clinical suspicion of its existence. The goal of this study was to assess the feasibility of measuring serum 7α-hydroxy-4-cholesten-3-one (C4) in dogs, as a potential marker of bile acid malabsorption, and to see whether this is related to clinical disease severity or the presence of hypocobalaminaemia. Serum C4 concentration was measured in 20 clinically healthy control dogs and 17 dogs with chronic diarrhoea. Three of the 17 affected dogs (17.6 per cent) had a C4 concentration significantly above the range of clinically healthy dogs; these dogs were all poorly responsive to conventional therapy. These results suggest that bile acid malabsorption may be a clinically relevant disorder in dogs with chronic diarrhoea and serum C4 may be a useful tool to investigate this further.

The Food and Drug Administration Office of Women's Health: Impact of Science on Regulatory Policy: An Update

The U.S. Food and Drug Administration Office of Women's Health (FDA OWH) has supported women's health research for ∼20 years, funding more than 300 studies on women's health issues, including research on diseases/conditions that disproportionately affect women in addition to the evaluation of sex differences in the performance of and response to medical products. These important women's health issues are studied from a regulatory perspective, with a focus on improving and optimizing medical product development and the evaluation of product safety and efficacy in women. These findings have influenced industry direction, labeling, product discontinuation, safety notices, and clinical practice. In addition, OWH-funded research has addressed gaps in the knowledge about diseases and medical conditions that impact women across the life span such as cardiovascular disease, pregnancy, menopause, osteoporosis, and the safe use of numerous medical products.

Recent admixture generates heterozygosity-fitness correlations during the range expansion of an invading species

Admixture, the mixing of historically isolated gene pools, can have immediate consequences for the genetic architecture of fitness traits. Admixture may be especially important for newly colonized populations, such as during range expansion and species invasions, by generating heterozygosity that can boost fitness through heterosis. Despite widespread evidence for admixture during species invasions, few studies have examined the demographic history leading to admixture, how admixture affects the heterozygosity and fitness of invasive genotypes, and whether such fitness effects are maintained through time. We address these questions using the invasive plant Silene vulgaris, which shows evidence of admixture in both its native Europe and in North America where it has invaded. Using multilocus genotype data in conjunction with approximate Bayesian computation analysis of demographic history, we showed that admixture during the invasion of North America was independent from and much younger than admixture in the native range of Europe. We tested for fitness consequences of admixture in each range and detected a significant positive heterozygosity-fitness correlation (HFC) in North America; in contrast, no HFC was present in Europe. The lack of HFC in Europe may reflect the longer time since admixture in the native range, dissipating associations between heterozygosity at markers and fitness loci. Our results support a key short-term role for admixture during the early stages of invasion by generating HFCs that carry populations past the threat of extinction from inbreeding and demographic stochasticity.

A New Signaling Pathway for HCV Inhibition by Estrogen: GPR30 Activation Leads to Cleavage of Occludin by MMP-9

Poor outcome in response to hepatitis C virus, including higher viral load, hepatocellular carcinoma and cirrhosis, is more associated with men and postmenopausal women than with premenopausal women and women receiving hormone replacement therapy, suggesting that β-estradiol plays an innate role in preventing viral infection and liver disease. Consequently, most research in the field has concluded that estrogen affects HCV replication through viral interactions with estrogen receptor-α. Previously, estrogen-like antagonists, including Tamoxifen, were shown to reduce HCV RNA production and prevent viral entry, although the authors did not identify host factors involved. Estrogen can act alternatively through the membrane-bound G-protein-coupled estrogen receptor, GPR30. Here, human hepatoma Huh7.5 cells were infected with HCV J6/JFH-1 and treated with estrogen or Tamoxifen, resulting in a marked decrease in detectable virus. The effect was mimicked by G1, a GPR30-specific agonist, and was reversed by the GPR30-specific antagonist, G15. While previous studies have demonstrated that estrogen down-regulated occludin in cervical cancer cells, its action on liver cells was unknown. Occludin is a tight junction protein and HCV receptor and here we report that activation and cellular export of MMP-9 led to the cleavage of occludin upon estrogen treatment of liver cells. This is the first report of the cleavage of an HCV receptor in response to estrogen. We also identify the occludin cleavage site in extracellular Domain D; the motif required for HCV entry and spread. This pathway gives new insight into a novel innate antiviral pathway and the suboptimal environment that estrogen provides for the proliferation of the virus. It may also explain the disparate host-virus responses to HCV demonstrated by the two sexes. Moreover, these data suggest that hormone replacement therapy may have beneficial antiviral enhancement properties for HCV-infected postmenopausal women and show promise for new antiviral treatments for both men and women.

Rapid detection of hepatitis B virus in blood plasma by a specific and sensitive loop-mediated isothermal amplification assay

BACKGROUND

Hepatitis B virus (HBV) is an important blood-borne pathogen that causes hepatic inflammation and can lead to liver cirrhosis and hepatocellular carcinoma. Conventional methods of HBV detection are time consuming and require highly trained personnel and elaborate equipment. This report describes the development of a rapid, simple, specific, and sensitive loop-mediated isothermal amplification assay (LAMP) for detection of HBV genotypes A, B, C, D, E, and F in blood samples.

METHODS

HBV standard plasma panels and clinical donor plasma specimens were used for the development and validation of the LAMP assay. Amplification was performed at 60°C for 60 minutes using extracted DNA or heat-treated plasma specimens without DNA extraction. The assay was evaluated for its ability to detect various HBV genotypes and for its sensitivity, specificity, and time-point of detection.

RESULTS

The LAMP assay detected HBV genotypes A-F and demonstrated a sensitivity of 10-100 IU per reaction of HBV DNA. The assay also detected 69 of 75 (92%) HBV-positive donor plasma specimens tested and demonstrated a specificity of 100%.

CONCLUSIONS

These results demonstrate that our HBV-LAMP assay is rapid, sensitive and specific, and capable of detecting the major HBV genotypes. This assay could be used in clinical point-of-care settings, mainly in endemic and resource-limited environments for HBV diagnostics, donor screening, epidemiological studies, and therapeutic monitoring of patients undergoing antiviral treatment.

Predicting steroid responsiveness in patients with asthma using exhaled breath profiling

BACKGROUND

Exhaled breath contains disease-dependent volatile organic compounds (VOCs), which may serve as biomarkers distinguishing clinical phenotypes in asthma. Their measurement may be particularly beneficial in relation to treatment response.

OBJECTIVE

Our aim was to compare the performance of electronic nose (eNose) breath analysis with previously investigated techniques (sputum eosinophils, exhaled nitric oxide (FeNO) and airway hyperresponsiveness) to discriminate asthma from controls and identify steroid responsiveness in steroid-free patients. Trial registration ACTRN12613000038796.

METHODS

Twenty-five patients with mild/moderate asthma had their inhaled steroid treatment discontinued until loss of control or 28 days. They were subsequently treated with oral prednisone 30 mg/day for 14 days. Steroid responsiveness was defined as an increase of either > 12% FEV1 or > 2 doubling doses PC20 AMP. Steroid-free assessment of sputum eosinophils, FeNO and exhaled breath VOCs were used to construct algorithms predicting steroid responsiveness. Performance characteristics were compared by ROC analysis.

RESULTS

The eNose discriminated between asthma and controls (area under the curve = 0.766 ± 0.14; P = 0.002) with similar accuracy to FeNO (0.862 ± 0.12; P < 0.001) and sputum eosinophils (0.814 ± 0.15; P < 0.001). Steroid responsiveness was predicted with greater accuracy by VOC-analysis (AUC = 0.883 ± 0.16; P = 0.008) than FeNO (0.545 ± 0.28; P = 0.751) or sputum eosinophils (0.610 ± 0.29; P = 0.441).

CONCLUSIONS AND CLINICAL RELEVANCE

Breath analysis by eNose can identify asthmatic patients and may be used to predict their response to steroids with greater accuracy than sputum eosinophils or FeNO. This implies a potential role for breath analysis in the tailoring of treatment for asthma patients.

Immunogenicity and protection efficacy of monomeric and trimeric recombinant SARS coronavirus spike protein subunit vaccine candidates

Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease, and an effective vaccine is not available. In this study, we compared the immunogenicity and protection efficacy of recombinant proteins corresponding to different domains of the SARS-coronavirus spike protein. Trimeric recombinant proteins were created by fusing the foldon domain derived from T4 bacteriophage to the carboxy-termini of individual domains of the spike protein. While the full-length ectodomain (S) of the spike protein, the full-length ectodomain fused to foldon (S-foldon), the S1 domain (S1), S1-foldon, and the S2 domain(S2) antigens all elicited comparable antibody titers as measured by ELISA, S-foldon induced a significantly higher titer of neutralizing antibody and S2 protein did not elicit virus neutralizing antibodies. When tested in a mouse virus replication model, all the mice vaccinated with the S1, S1-foldon, S, or S-foldon were completely protected.

Altering SARS coronavirus frameshift efficiency affects genomic and subgenomic RNA production

In previous studies, differences in the amount of genomic and subgenomic RNA produced by coronaviruses with mutations in the programmed ribosomal frameshift signal of ORF1a/b were observed. It was not clear if these differences were due to changes in genomic sequence, the protein sequence or the frequency of frameshifting. Here, viruses with synonymous codon changes are shown to produce different ratios of genomic and subgenomic RNA. These findings demonstrate that the protein sequence is not the primary cause of altered genomic and subgenomic RNA production. The synonymous codon changes affect both the structure of the frameshift signal and frameshifting efficiency. Small differences in frameshifting efficiency result in dramatic differences in genomic RNA production and TCID₅₀ suggesting that the frameshifting frequency must stay above a certain threshold for optimal virus production. The data suggest that either the RNA sequence or the ratio of viral proteins resulting from different levels of frameshifting affects viral replication.

RNA dimerization plays a role in ribosomal frameshifting of the SARS coronavirus

Messenger RNA encoded signals that are involved in programmed -1 ribosomal frameshifting (-1 PRF) are typically two-stemmed hairpin (H)-type pseudoknots (pks). We previously described an unusual three-stemmed pseudoknot from the severe acute respiratory syndrome (SARS) coronavirus (CoV) that stimulated -1 PRF. The conserved existence of a third stem–loop suggested an important hitherto unknown function. Here we present new information describing structure and function of the third stem of the SARS pseudoknot. We uncovered RNA dimerization through a palindromic sequence embedded in the SARS-CoV Stem 3. Further in vitro analysis revealed that SARS-CoV RNA dimers assemble through ‘kissing’ loop–loop interactions. We also show that loop–loop kissing complex formation becomes more efficient at physiological temperature and in the presence of magnesium. When the palindromic sequence was mutated, in vitro RNA dimerization was abolished, and frameshifting was reduced from 15 to 5.7%. Furthermore, the inability to dimerize caused by the silent codon change in Stem 3 of SARS-CoV changed the viral growth kinetics and affected the levels of genomic and subgenomic RNA in infected cells. These results suggest that the homodimeric RNA complex formed by the SARS pseudoknot occurs in the cellular environment and that loop–loop kissing interactions involving Stem 3 modulate -1 PRF and play a role in subgenomic and full-length RNA synthesis.

Biochemical characterization of a recombinant SARS coronavirus nsp12 RNA-dependent RNA polymerase capable of copying viral RNA templates

The severe acute respiratory syndrome coronavirus (SARS-CoV) RNA genome is replicated by a virus-encoded RNA replicase, the key component of which is the nonstructural protein 12 (nsp12). In this report, we describe the biochemical properties of a full-length recombinant SARS-CoV nsp12 RNA-dependent RNA polymerase (RdRp) capable of copying viral RNA templates. The purified SARS-CoV nsp12 showed both primer-dependent and primer-independent RNA synthesis activities using homopolymeric RNA templates. The RdRp activity was strictly dependent on Mn²⁺. The nsp12 preferentially copied homopolymeric pyrimidine RNA templates in the absence of an added oligonucleotide primer. It was also able to initiate de novo RNA synthesis from the 3’-ends of both the plus- and minus-strand genome of SARS-CoV, using the 3’-terminal 36- and 37-nt RNA, respectively. The in vitro RdRp assay system established with a full-length nsp12 will be useful for understanding the mechanisms of coronavirus replication and for the development of anti-SARS-CoV agents.

Distribution of hepatitis C virus in circulating blood components from blood donors

BACKGROUND AND OBJECTIVES

Current nucleic acid tests (NAT) for blood donor screening use plasma as the test sample and, consequently, cannot detect virions bound to blood cells of infected donors. Hepatitis C virus (HCV) RNA and infectious virions have been detected in association with the cellular components of blood of patients with active liver disease; however, studies comparing HCV viral loads in whole blood and plasma have generated contradictory results. The aim of this study was to investigate the distribution of HCV in different compartments of the peripheral blood from HCV-infected blood donors, which may differ from that observed in patients with HCV-associated liver disease.

MATERIALS AND METHODS

Hepatitis C virus-positive donor specimens were identified by NAT and antibody testing. HCV RNA was extracted from samples of whole blood and their corresponding components (RBC and plasma). Viral RNA was quantified by real-time qRT-PCR.

RESULTS

Hepatitis C virus was present in all blood components from infected donors from which RNA could be amplified. For the majority of samples, plasma (34/46) had the highest detectable concentration of HCV RNA, and RBC (37/46) had the lowest. Specimens with negative NAT and positive antibody assays also produced qRT-PCR negative results.

CONCLUSION

These results indicate that including the RBC fraction in the tested sample will not increase assay sensitivity. Although 10% of the specimens had a higher viral load in whole blood, there was no significant overall increase in sensitivity to justify changes in the specimen format. Thus, plasma specimens are well suited for blood donor screening for HCV.

Interference of ribosomal frameshifting by antisense peptide nucleic acids suppresses SARS coronavirus replication

The programmed −1 ribosomal frameshifting (−1 PRF) utilized by eukaryotic RNA viruses plays a crucial role for the controlled, limited synthesis of viral RNA replicase polyproteins required for genome replication. The viral RNA replicase polyproteins of severe acute respiratory syndrome coronavirus (SARS-CoV) are encoded by the two overlapping open reading frames 1a and 1b, which are connected by a −1 PRF signal. We evaluated the antiviral effects of antisense peptide nucleic acids (PNAs) targeting a highly conserved RNA sequence on the – PRF signal. The ribosomal frameshifting was inhibited by the PNA, which bound sequence-specifically a pseudoknot structure in the −1 PRF signal, in cell lines as assessed using a dual luciferase-based reporter plasmid containing the −1 PRF signal. Treatment of cells, which were transfected with a SARS-CoV-replicon expressing firefly luciferase, with the PNA fused to a cell-penetrating peptide (CPP) resulted in suppression of the replication of the SARS-CoV replicon, with a 50% inhibitory concentration of 4.4 μM. There was no induction of type I interferon responses by PNA treatment, suggesting that the effect of PNA is not due to innate immune responses. Our results demonstrate that −1 PRF, critical for SARS-CoV viral replication, can be inhibited by CPP-PNA, providing an effective antisense strategy for blocking −1 PRF signals.

Persistent growth of a human plasma-derived hepatitis C virus genotype 1b isolate in cell culture

HCV (hepatitis C virus) research, including therapeutics and vaccine development, has been hampered by the lack of suitable tissue culture models. Development of cell culture systems for the growth of the most drug-resistant HCV genotype (1b) as well as natural isolates has remained a challenge. Transfection of cultured cells with adenovirus-associated RNA_I (VA RNA_I), a known interferon (IFN) antagonist and inhibitor of dsRNA-mediated antiviral pathways, enhanced the growth of plasma-derived HCV genotype 1b. Furthermore, persistent viral growth was achieved after passaging through IFN-α/β-deficient VeroE6 cells for 2 years. Persistently infected cells were maintained in culture for an additional 4 years, and the virus rescued from these cells induced strong cytopathic effect (CPE). Using a CPE-based assay, we measured inhibition of viral production by anti-HCV specific inhibitors, including 2′-C-Methyl-D-Adenosine, demonstrating its utility for the evaluation of HCV antivirals. This virus constitutes a novel tool for the study of one of the most relevant strains of HCV, genotype 1b, which will now be available for HCV life cycle research and useful for the development of new therapeutics.

Hepatitis C virus (HCV) causes a persistent infection that can lead to hepatocellular carcinoma and liver cirrhosis. Interferon (IFN)-based treatments are ineffective for some HCV genotypes. HCV research has been hampered by the lack of suitable cell culture systems. With the discovery of a unique HCV genotype 2a isolate that can replicate in the human liver cell line Huh7, some obstacles were overcome. However, there remains the need of systems to grow IFN-resistant genotypes and serum-derived isolates. Here we show that the presence of adenovirus-associated RNA_I (VA RNA_I), a known IFN antagonist, permitted establishment of a persistent infection of genotype 1b in VeroE6 cells that were passaged weekly for more than 2 years. The persistent virus induces strong cytopathic effect (CPE), a feature that allowed the development of a CPE-based assay to test HCV-specific inhibitors, neutralization by anti-HCV immunoglobulins and by anti-CD81 antibody, and HCV-specific siRNA. Our system provides the first persistent culture of genotype 1b virus and a convenient assay that can be used for therapeutics development.

Characterization of aurintricarboxylic acid as a potent hepatitis C virus replicase inhibitor

BACKGROUND

Hepatitis C virus (HCV) NS5B is an essential component of the viral replication machinery and an important target for antiviral intervention. Aurintricarboxylic acid (ATA), a broad-spectrum antiviral agent, was evaluated and characterized for its anti-NS5B activity in vitro and in HCV replicon cells.

METHODS

Recombinant NS5B, HCV replicase and Huh-7 cells harbouring the subgenomic HCV replicon of genotype 1b were employed for biochemical and mechanistic investigations.

RESULTS

Analysis of ATA activity in vitro yielded equipotent inhibition of recombinant NS5B and HCV replicase in the submicromolar range (50% inhibition concentration [IC(50)] approximately 150 nM). Biochemical and mechanistic studies revealed a bimodal mechanism of ATA inhibition with characteristics of pyrophosphate mimics and non-nucleoside inhibitors. Molecular modelling and competition displacement studies were consistent with these parameters, suggesting that ATA might bind to the benzothiadiazine allosteric pocket 3 of NS5B or at its catalytic centre. Kinetic studies revealed a mixed mode of ATA inhibition with respect to both RNA and UTP substrates. Under single-cycle assay conditions, ATA inhibited HCV NS5B initiation and elongation from pre-bound RNA, but with > or =fivefold decreased potency compared with continuous polymerization conditions. The IC(50) value of ATA for the native replicase complex was 145 nM. In HCV replicon cells, ATA treatment ablated HCV RNA replication (50% effective concentration =75 nM) with concomitant decrease in NS5B expression and no apparent cytotoxic effects.

CONCLUSIONS

This study identified ATA as a potent anti-NS5B inhibitor and suggests that its unique mode of action might be exploited for structural refinement and development of novel anti-NS5B agents.

Effects of cannabis on lung function: a population-based cohort study

The effects of cannabis on lung function remain unclear and may be different from those of tobacco. We compared the associations between use of these substances and lung function in a population-based cohort (n = 1,037). Cannabis and tobacco use were reported at ages 18, 21, 26 and 32 yrs. Spirometry, plethysmography and carbon monoxide transfer factor were measured at 32 yrs. Associations between lung function and exposure to each substance were adjusted for exposure to the other substance. Cumulative cannabis use was associated with higher forced vital capacity, total lung capacity, functional residual capacity and residual volume. Cannabis was also associated with higher airway resistance but not with forced expiratory volume in 1 s, forced expiratory ratio or transfer factor. These findings were similar among those who did not smoke tobacco. In contrast, tobacco use was associated with lower forced expiratory volume in 1 s, lower forced expiratory ratio, lower transfer factor and higher static lung volumes, but not with airway resistance. Cannabis appears to have different effects on lung function from those of tobacco. Cannabis use was associated with higher lung volumes, suggesting hyperinflation and increased large-airways resistance, but there was little evidence for airflow obstruction or impairment of gas transfer.

Innate immunity and hepatitis C virus: eluding the host cell defense

Interferon-alpha (IFN-alpha) mono-therapy is largely ineffective for most of the hepatitis C virus (HCV)-infected patients that receive it. The addition of ribavirin to IFN therapy has increased the response rate dramatically. While many factors are implicated in determining the success rate for IFN therapy, viral genotype seems to play a crucial role. Examining differences in viral gene sequences has and will continue to advance our understanding as to how HCV and other viruses circumvent the IFN response. Here we review the different ways that HCV evades the immune response elicited by IFN.

Biomarkers in the assessment and management of airways diseases

A plethora of biomarkers are becoming available in the field of respiratory medicine, but their application in clinical practice has been limited. This is changing. There is increasing scope for biomarkers to be used to define pathological as well as treatment responder phenotypes in asthma and chronic obstructive pulmonary disease. In some situations, conventional diagnostic labelling is being superseded by this approach and clinical outcomes are improved. Biomarkers are potentially very important in the development and assessment of new therapeutic agents, particularly for the treatment of severe asthma. They also have a potential role in monitoring disease activity and predicting future clinical outcomes for asthma and chronic obstructive pulmonary disease. Current evidence in relation to these issues is explored in this review.

Risk assessment in asthma and COPD: a potential role for biomarkers?

There is an increasing literature on the pathological and clinical significance of "inflammatory" biomarkers in asthma and chronic obstructive pulmonary disease (COPD). Their potential role includes risk assessment, but this is somewhat different for the two conditions. In asthma the aim is to identify future risk of poor asthma control or exacerbations. Although induced sputum eosinophils and exhaled nitric oxide are the most widely investigated candidates for use in the clinical arena, there is scope for a great deal of improvement in their application and other biomarkers may prove to be better. For COPD, risk assessment is somewhat different. There is the potential to use biomarkers such as C-reactive protein, fibrinogen or interleukin 6, along with other conventional demographic and physiological measurements, to assess longer term risk of decline in lung function, hospitalisations and mortality. The well-tried model used in cardiovascular disease to assess absolute risk might possibly be adapted for use in COPD, and this should be actively explored.

A new perspective on concepts of asthma severity and control

Concepts of asthma severity and control are important in the evaluation of patients and their response to treatment but the terminology is not standardised and the terms are often used interchangeably. This review, arising from the work of an American Thoracic Society/European Respiratory Society Task Force, identifies the need for separate concepts of control and severity, describes their evolution in asthma guidelines and provides a framework for understanding the relationship between current concepts of asthma phenotype, severity and control. "Asthma control" refers to the extent to which the manifestations of asthma have been reduced or removed by treatment. Its assessment should incorporate the dual components of current clinical control (e.g. symptoms, reliever use and lung function) and future risk (e.g. exacerbations and lung function decline). The most clinically useful concept of asthma severity is based on the intensity of treatment required to achieve good asthma control, i.e. severity is assessed during treatment. Severe asthma is defined as the requirement for (not necessarily just prescription or use of) high-intensity treatment. Asthma severity may be influenced by the underlying disease activity and by the patient's phenotype, both of which may be further described using pathological and physiological markers. These markers can also act as surrogate measures for future risk.

Fluctuation analysis of lung function as a predictor of long-term response to beta2-agonists

The response to beta(2)-agonists differs between asthmatics and has been linked to subsequent adverse events, even death. Possible determinants include beta(2)-adrenoceptor genotype at position 16, lung function and airway hyperresponsiveness. Fluctuation analysis provides a simple parameter alpha measuring the complex correlation properties of day-to-day peak expiratory flow. The present study investigated whether alpha predicts clinical response to beta(2)-agonist treatment, taking into account other conventional predictors. Analysis was performed on previously published twice-daily peak expiratory flow measurements in 66 asthmatic adults over three 6-month randomised order treatment periods: placebo, salbutamol and salmeterol. Multiple linear regression was used to determine the association between alpha during the placebo period and response to treatment (change in the number of days with symptoms), taking into account other predictors namely beta(2)-adrenoceptor genotype, lung function and its variability, and airway hyperresponsiveness. The current authors found that alpha measured during the placebo period considerably improved the prediction of response to salmeterol treatment, taking into account genotype, lung function or its variability, or airway hyperresponsiveness. The present study provides further evidence that response to beta(2)-agonists is related to the time correlation properties of lung function in asthma. The current authors conclude that fluctuation analysis of lung function offers a novel predictor to identify patients who may respond well or poorly to treatment.

Pseudomonas aeruginosa transmission is infrequent in New Zealand cystic fibrosis clinics

Pseudomonas aeruginosa is an important pathogen in cystic fibrosis (CF). Although most patients harbour unique P. aeruginosa isolates, some clinics report patients sharing common strains. The overall importance of person-to-person transmission in P. aeruginosa acquisition and whether routine patient segregation is necessary remains uncertain. The present authors therefore investigated the extent of P. aeruginosa transmission in New Zealand CF clinics. New Zealand's seven major CF centres were assessed, combining epidemiological data with computer-assisted SalI DNA fingerprinting of 496 isolates from 102 patients. One cluster of related isolates was significantly more prevalent in the largest clinic than expected by chance. The seven patients with isolates belonging to this cluster had more contact with each other than the remaining patients attending this centre. No other convincing evidence of transmission was found in any of the other smaller clinics. Three P. aeruginosa strains believed to be transmissible between patients in Australian and British CF clinics are present in New Zealand, but there was no definite evidence they had spread. Pseudomonas aeruginosa transmission is currently infrequent in New Zealand cystic fibrosis clinics. This situation could change rapidly and ongoing surveillance is required. The current results confirm that computer-assisted SalI DNA fingerprinting is ideally suited for such surveillance.

Overcoming hurdles in hepatitis C virus research: efficient production of infectious virus in cell culture

Hepatitis C virus is a flavivirus that infects nearly 2% of the world population. There is no vaccine available and current therapy with interferon and ribavirin is expensive, not well tolerated and effective in only 60% of patients. HCV research has been hampered by the lack of a robust tissue culture system, but recent advances have made virus growth in culture possible. Here we review the current state-of-the-art and the molecular hurdles that have been met and those that still need to be overcome.

Abnormal cation exchange in insulin-resistant patients with essential hypertension

OBJECTIVES

To identify important factors that may contribute to abnormal glucose tolerance in elderly patients with treated hypertension with primary reference to changes in the following parameters: calculated insulin resistance, endogenous insulin processing and secretion; platelet cation concentration and membrane ATPase activity.

DESIGN

Thirty-nine patients receiving antihypertensive therapy (including low-dose thiazide treatment) were compared to 13 normotensive, normoglycaemic control subjects. Total platelet cation concentration and membrane ATPase activity were measured and, following a 75-g oral glucose test, serum insulin, proinsulin and 31-32 des-proinsulin responses were measured in prospectively defined hypertensive patients with normal glucose tolerance (NG), impaired glucose tolerance (IGT) and diabetes mellitus (DM).

RESULTS

Of the total patient cohort, seven patients manifested newly diagnosed DM, 18 had IGT and 14 NG. Among the three groups, no difference in duration of drug use (thiazides and beta-blockers) was noted; BMI and waist-to-hip ratio increased progressively from NG to IGT to overt DM. Compared to NG patients, serum insulin responses were significantly greater in the IGT (all time points) and DM (two-hour measurements) subjects. Proinsulin and 31-32 des-proinsulin serum responses were likewise significantly higher in the IGT and DM groups. The derived measure of insulin resistance in the hypertensive patients showed a significant increase in the progression from NG to IGT and DM. Mean total platelet potassium concentration was reduced in the DM compared to the IGT and the control groups, while platelet sodium, calcium and magnesium concentrations showed no significant differences. Platelet membrane magnesium ATPase activity was significantly higher in the normotensive control versus the hypertensive group. Sodium, potassium and calcium ATPase activity showed no significant differences among the subgroups.

CONCLUSION

Our findings support the strong link between essential hypertension, insulin resistance/hyperinsulinaemia and regional adiposity. Beta-cell dysfunction (hypersecretion and abnormal insulin processing) is manifest in the progression from normality to overt diabetes. The use of antihypertensive therapy (low-dose thiazides and cardioselective beta-blockers) possibly added diabetogenic effect(s). The reduction in platelet total potassium concentration paralleled the diabetic state while a reduced membrane magnesium ATPase activity correlated with the hypertensive state.

Severe acute respiratory syndrome coronavirus infection in vaccinated ferrets

BACKGROUND

Development of vaccines to prevent severe acute respiratory syndrome (SARS) is limited by the lack of well-characterized animal models. Previous vaccine reports have noted robust neutralizing antibody and inflammatory responses in ferrets, resulting in enhanced hepatitis.

METHODS

We evaluated the humoral immune response and pathological end points in ferrets challenged with the Urbani strain of SARS-associated coronavirus (SARS-CoV) after having received formalin-inactivated whole-virus vaccine or mock vaccine.

RESULTS

Humoral responses were observed in ferrets that received an inactivated virus vaccine. Histopathological findings in lungs showed that infection of ferrets produced residual lung lesions not seen in both mock and vaccinated ferrets. SARS-CoV infection demonstrated bronchial and bronchiolar hyperplasia and perivascular cuffing in ferret lung tissue, as seen previously in infected mice. No evidence of enhanced disease was observed in any of the ferrets. All of the ferrets cleared the virus by day 14, 1 week earlier if vaccinated.

CONCLUSIONS

The vaccine provided mild immune protection to the ferrets after challenge; however, there was no evidence of enhanced liver or lung disease induced by the inactivated whole-virus vaccine. The ferret may provide another useful model for evaluating SARS vaccine safety and efficacy.

Sex ratio variance and the maintenance of environmental sex determination

Although variation in population sex ratios is predicted to increase the extinction rate of clades with environmental sex determination (ESD), ESD is still seen in a wide array of natural systems. It is unclear how this common sex-determining system has persisted despite this inherent disadvantage associated with ESD. We use simulation modelling to examine the effect of the sex ratio variance caused by ESD on population colonization and establishment. We find that an accelerating function of establishment success on initial population sex ratio favours a system that produces variance in sex ratios over one that consistently produces even sex ratios. This sex ratio variance causes ESD to be favoured over genetic sex determination, even when the mean global sex ratio under both sex-determining systems is the same. Data from ESD populations suggest that the increase in population establishment can more than offset the increased risk of extinction associated with temporal fluctuations in the sex ratio. These findings demonstrate that selection in natural systems can favour increased variance in a trait, irrespective of the mean trait value. Our results indicate that sex ratio variation may provide an advantage to species with ESD, and may help explain the widespread existence of this sex-determining system.

Evaluation of inactivation methods for severe acute respiratory syndrome coronavirus in noncellular blood products

BACKGROUND: Severe acute respiratory syndrome coronavirus (SARS‐CoV) has been detected in the blood of infected individuals, which may have the potential to contaminate donated blood and plasma‐derived products in the event of a future outbreak. Effective methods for inactivating the SARS‐CoV in protein solutions are described in this report.

STUDY DESIGN AND METHODS: Heat, ultraviolet (UV) irradiation, octanoic acid, and solvent/detergent (S/D) methods were tested individually for their ability to inactivate SARS‐CoV in protein solutions appropriately mimicking blood‐derived products. Treated samples were tested for inactivation in a tissue culture growth assay.

RESULTS: Viral inactivation by heat treatment at 60°C required 15 to 30 minutes to inactivate the SARS‐CoV. UVC efficiently inactivated SARS‐CoV in 40 minutes, whereas UVA required the addition of psoralen to enhance inactivation of the virus. The presence of bovine serum albumin limited the ability of UVC and UVA to inactivate SARS‐CoV and octanoic acid treatment does not reduce the infectivity of SARS‐CoV–spiked protein solutions. S/D treatment required 2, 4, and up to 24 hours for Triton X‐100, Tween 80, and sodium cholate inactivation, respectively.

CONCLUSION: Heat, UVC irradiation, and S/D treatments effectively inactivate SARS‐CoV, whereas octanoic acid treatment is insufficient for inactivation of the virus.

Exhaled nitric oxide measurements: clinical application and interpretation

The use of exhaled nitric oxide measurements (F(E)NO) in clinical practice is now coming of age. There are a number of theoretical and practical factors which have brought this about. Firstly, F(E)NO is a good surrogate marker for eosinophilic airway inflammation. High F(E)NO levels may be used to distinguish eosinophilic from non-eosinophilic pathologies. This information complements conventional pulmonary function testing in the assessment of patients with non-specific respiratory symptoms. Secondly, eosinophilic airway inflammation is steroid responsive. There are now sufficient data to justify the claim that F(E)NO measurements may be used successfully to identify and monitor steroid response as well as steroid requirements in the diagnosis and management of airways disease. F(E)NO measurements are also helpful in identifying patients who do/do not require ongoing treatment with inhaled steroids. Thirdly, portable nitric oxide analysers are now available, making routine testing a practical possibility. However, a number of issues still need to be resolved, including the diagnostic role of F(E)NO in preschool children and the use of reference values versus individual F(E)NO profiles in managing patients with difficult or severe asthma.

Care plans for acutely deteriorating COPD: a randomized controlled trial

INTRODUCTION

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are a frequent reason for admission to hospital and are responsible for the majority of the direct economic costs of treating COPD.

AIMS

To test whether an individualized care plan for patients experiencing acute exacerbations of COPD result in reduced health care utilization and improved quality of life for patients.

METHODS

Ninety-two patients with confirmed COPD were selected by general practitioners or district nurses, and randomly assigned to care plan or usual care groups. The care plan was developed in collaboration with general practitioners, secondary care specialists, specialist nurses, ambulance service providers and the after hours clinic. Patients were followed for 12 months, and the primary end-points were frequency of use of primary care services and hospital admissions.

RESULTS

There was no significant reduction in hospital admissions or improvement in quality of life in the group of patients who used the care plan compared to controls. The care plan group called out the ambulance service more frequently [2.8 (1.3, 4.3) versus 1.1 (0.7, 1.5) calls per 12 months; P = 0.03], and there was a trend towards greater use of oral prednisone [2.3 (1.4, 3.2) versus 1.3 (0.8, 1.8) courses per 12 months; P = 0.06].

CONCLUSION

In contrast to asthma, the provision of individualized self-management plans, whose content was enhanced to provide guidance to carers and health care professionals, did not reduce health care utilization or improve overall quality of life during acute exacerbations of COPD. Other strategies are required.

Obstacles and advances in SARS vaccine development

The emergence of the severe acute respiratory syndrome (SARS) that resulted in a pandemic in 2003 spurred a flurry of interest in the development of vaccines to prevent and treat the potentially deadly viral infection. Researchers around the world pooled their scientific resources and shared early data in an unprecedented manner in light of the impending public health crisis. There are still large gaps in knowledge about the pathogenesis of this virus. While significant advances have been made in the development of animal models, the practicality of their use may be hampered by a lack of pathological similarity with human disease. Described here are issues related to progress in vaccine development and the obstacles that lie ahead for both researchers and regulatory agencies.

New antiviral pathway that mediates hepatitis C virus replicon interferon sensitivity through ADAR1

While many clinical hepatitis C virus (HCV) infections are resistant to alpha interferon (IFN-alpha) therapy, subgenomic in vitro self-replicating HCV RNAs (HCV replicons) are characterized by marked IFN-alpha sensitivity. IFN-alpha treatment of replicon-containing cells results in a rapid loss of viral RNA via translation inhibition through double-stranded RNA-activated protein kinase (PKR) and also through a new pathway involving RNA editing by an adenosine deaminase that acts on double-stranded RNA (ADAR1). More than 200 genes are induced by IFN-alpha, and yet only a few are attributed with an antiviral role. We show that inhibition of both PKR and ADAR1 by the addition of adenovirus-associated RNA stimulates replicon expression and reduces the amount of inosine recovered from RNA in replicon cells. Small inhibitory RNA, specific for ADAR1, stimulated the replicon 40-fold, indicating that ADAR1 has a role in limiting replication of the viral RNA. This is the first report of ADAR's involvement in a potent antiviral pathway and its action to specifically eliminate HCV RNA through adenosine to inosine editing. These results may explain successful HCV replicon clearance by IFN-alpha in vitro and may provide a promising new therapeutic strategy for HCV as well as other viral infections.

Inactivation of the coronavirus that induces severe acute respiratory syndrome, SARS-CoV

Severe acute respiratory syndrome (SARS) is a life-threatening disease caused by a novel coronavirus termed SARS-CoV. Due to the severity of this disease, the World Health Organization (WHO) recommends that manipulation of active viral cultures of SARS-CoV be performed in containment laboratories at biosafety level 3 (BSL3). The virus was inactivated by ultraviolet light (UV) at 254 nm, heat treatment of 65 °C or greater, alkaline (pH > 12) or acidic (pH < 3) conditions, formalin and glutaraldehyde treatments. We describe the kinetics of these efficient viral inactivation methods, which will allow research with SARS-CoV containing materials, that are rendered non-infectious, to be conducted at reduced safety levels.

Inactivation of the coronavirus that induces severe acute respiratory syndrome, SARS-CoV

Severe acute respiratory syndrome (SARS) is a life-threatening disease caused by a novel coronavirus termed SARS-CoV. Due to the severity of this disease, the World Health Organization (WHO) recommends that manipulation of active viral cultures of SARS-CoV be performed in containment laboratories at biosafety level 3 (BSL3). The virus was inactivated by ultraviolet light (UV) at 254 nm, heat treatment of 65 degrees C or greater, alkaline (pH > 12) or acidic (pH < 3) conditions, formalin and glutaraldehyde treatments. We describe the kinetics of these efficient viral inactivation methods, which will allow research with SARS-CoV containing materials, that are rendered non-infectious, to be conducted at reduced safety levels.

Inactivation of the coronavirus that induces severe acute respiratory syndrome, SARS-CoV

Severe acute respiratory syndrome (SARS) is a life-threatening disease caused by a novel coronavirus termed SARS-CoV. Due to the severity of this disease, the World Health Organization (WHO) recommends that manipulation of active viral cultures of SARS-CoV be performed in containment laboratories at biosafety level 3 (BSL3). The virus was inactivated by ultraviolet light (UV) at 254 nm, heat treatment of 65 degrees C or greater, alkaline (pH > 12) or acidic (pH < 3) conditions, formalin and glutaraldehyde treatments. We describe the kinetics of these efficient viral inactivation methods, which will allow research with SARS-CoV containing materials, that are rendered non-infectious, to be conducted at reduced safety levels.

Relationship between socioeconomic status and asthma: a longitudinal cohort study

BACKGROUND

There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors.

METHODS

We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models.

RESULTS

No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports.

CONCLUSIONS

Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding.

Respiratory health effects of cannabis: position statement of the Thoracic Society of Australia and New Zealand

Both the gaseous and the particulate phases of tobacco and cannabis smoke contain a similar range of harmful chemicals. However, differing patterns of inhalation mean that smoking a 'joint' of cannabis results in exposure to significantly greater amounts of combusted material than with a tobacco cigarette. The histopathological effects of cannabis smoke exposure include changes consistent with acute and chronic bronchitis. Cellular dysplasia has also been observed, suggesting that, like tobacco smoke, cannabis exposure has the potential to cause malignancy. These features are consistent with the clinical presentation. Symptoms of cough and early morning sputum production are common (20-25%) even in young individuals who smoke cannabis alone. Almost all studies indicate that the effects of cannabis and tobacco smoking are additive and independent. Public health education should dispel the myth that cannabis smoking is relatively safe by highlighting that the adverse respiratory effects of smoking cannabis are similar to those of smoking tobacco, even although it remains to be confirmed that smoking cannabis alone leads to the development of chronic lung disease.

Bronchodilator tolerance: the impact of increasing bronchoconstriction

Chronic exposure to beta-agonists causes tolerance to their bronchodilator effects, which is best demonstrated during acute bronchoconstriction. The aim of the present study was to assess whether tolerance becomes more evident with increasing bronchoconstriction, as might occur in acute asthma. In a randomised, double-blind, placebo-controlled, crossover study comprising 15 patients, the treatments were salbutamol 400 microg q.i.d. or placebo given via Diskhaler for 28 days with a 2-week washout between treatments. Patients attended on days 14, 21 and 28. Bronchoconstriction was induced on two of these three occasions to achieve a reduction in the forced expiratory volume in one second (FEV1) of 0 (no methacholine), 15 and 30% (using methacholine) in a randomised order. Immediately after this, salbutamol 100 microg, 100 microg and 200 microg was inhaled at 0, 5, and 10 min. FEV1 was measured over 40 min. Dose/response curves were plotted and values for the area under the curve (AUC)0-40 FEV1 were compared between treatments and by degree of bronchoconstriction. Regular salbutamol resulted in attenuation of the acute response to beta-agonist, which was increasingly evident with greater bronchoconstriction. With a reduction in FEV1 of 0, 15 and 30%, the AUC0-40 FEV1 with salbutamol were 11.2, -14.6 and -35.7% respectively, compared to placebo. There was a linear relationship between the magnitude of bronchoconstriction and the between-treatment differences in AUC0-40 FEV1. Increasing bronchoconstriction conferred greater susceptibility to the effects of bronchodilator tolerance.

Protein synthesis and endoplasmic reticulum stress can be modulated by the hepatitis C virus envelope protein E2 through the eukaryotic initiation factor 2alpha kinase PERK

The hepatitis C virus envelope protein, E2, is an endoplasmic reticulum (ER)-bound protein that contains a region of sequence homology with the double-stranded RNA-activated protein kinase PKR and its substrate, the eukaryotic translation initiation factor 2 (eIF2). We previously reported that E2 modulates global translation through inhibition of the interferon-induced antiviral protein PKR through its PKR-eIF2alpha phosphorylation site homology domain (PePHD). Here we show that the PKR-like ER-resident kinase (PERK) binds to and is also inhibited by E2. At low expression levels, E2 induced ER stress, but at high expression levels, and in vitro, E2 inhibited PERK kinase activity. Mammalian cells that stably express E2 were refractory to the translation-inhibitory effects of ER stress inducers, and E2 relieved general translation inhibition induced by PERK. The PePHD of E2 was required for the rescue of translation that was inhibited by activated PERK, similar to our previous findings with PKR. Here we report the inhibition of a second eIF2alpha kinase by E2, and these results are consistent with a pseudosubstrate mechanism of inhibition of eIF2alpha kinases. These findings may also explain how the virus promotes persistent infection by overcoming the cellular ER stress response.

Exhaled NO and assessment of anti-inflammatory effects of inhaled steroid: dose-response relationship

Exhaled nitric oxide (eNO) is an easily measured marker of airway inflammation. This study was undertaken to evaluate the usefulness of serial eNO in investigating the dose-response relationship for inhaled beclomethasone (BDP), and to compare eNO with other markers of airway inflammation. Following withdrawal of inhaled corticosteroid (ICS) therapy, 65 patients entered a double-blind, parallel-group, placebo-controlled trial of 50, 100, 200 or 500 microg x BDP x day(-1) for eight weeks. eNO and spirometry were performed weekly and a hypertonic saline challenge with sputum induction was performed at the beginning and end of treatment. The relationship between the dose of ICS and changes in eNO and forced expiratory volume in one second (FEV1) was linear at 1 week and at the end of treatment. A linear dose-response relationship was also seen for sputum eosinophils. Changes in eNO correlated significantly with changes in sputum eosinophils. Changes in the provocative dose of saline causing a 15% fall in FEV1 saline did not differ across the treatment groups nor did they correlate with changes in other measurements. Exhaled nitric oxide may be used to assess the dose-response relationship for the anti-inflammatory effects of inhaled beclomethasone. The relationship found in this study was linear over the dose range 0-500 microg x day(-1) soon after commencing therapy and continued over time.

Genetic variation of the beta(2)-adrenoceptor: its functional and clinical importance in bronchial asthma

Asthma is a polygenic disease for which no clear genotype-phenotype relationships have emerged. In contrast, although not associated with the diagnosis of asthma per se, variant forms of the beta(2)-adrenoceptor (beta2-AR) gene (ADRB2) display functional effects that may be clinically relevant. Single nucleotide polymorphisms (SNPs) of ADBR2 are common and result in amino acid substitutions at positions 16, 27, and 164 of the receptor as well as position 19 of its 5' upstream peptide. These SNPs influence receptor function in vitro, although evidence regarding exact relationships is conflicting. This has raised the possibility that phenotypes such as bronchial hyper-responsiveness (BHR) and responses to (beta2)-agonist drugs may be genetically determined. To date, no unequivocal relationships between SNPs and phenotype have been identified. In some studies the Gly(16) allele has been associated with increased BHR and asthma severity. In others, the Arg(16) allele has been shown to determine acute bronchodilator response and adverse events during long term beta(2)-agonist therapy. The latter may provide the basis for clinical application of this new knowledge. More recently, a small number of frequently occurring, functionally relevant ADRB2 haplotype pairs have been confirmed. These combinations of alleles may be more important in determining genotype/phenotype relationships than individual SNPs, and may explain why earlier investigations have yielded contrasting results. Future studies will be required to clarify the pharmacodynamic effects of ADRB2haplotypes both in vitro and in vivo.

Detection of a novel unglycosylated form of hepatitis C virus E2 envelope protein that is located in the cytosol and interacts with PKR

The hepatitis C virus (HCV) envelope protein E2 has been shown to accumulate in the lumen of the endoplasmic reticulum (ER) as a properly folded glycoprotein as well as large aggregates of misfolded proteins. In the present study, we have identified an additional unglycosylated species, with an apparent molecular mass of 38 kDa (E2-p38). In contrast to the glycosylated E2, E2-p38 is significantly less stable and is degraded through the proteasome pathway. Correspondingly, E2-p38 is found to be ubiquitinated. E2-p38 is localized mostly in the cytosol, in contrast to the glycosylated form, which is exclusively membrane associated. Alpha interferon (IFN-alpha) treatment or overexpression of the double-stranded RNA-activated protein kinase (PKR) significantly increased the stability of E2-p38, consistent with a previous report (D. R. Taylor, S. T. Shi, P. R. Romano, G. N. Barber, and M. M. Lai, Science 285:107-110, 1999) that E2 interacts with PKR and inhibits its kinase activity. Direct interaction between PKR and E2-p38, but not the glycosylated form of E2, was also observed. These results show that E2-p38 is the form of E2 that interacts with PKR in the cytosol and may contribute to the resistance of HCV to IFN-alpha. Thus, an ER protein can exist in the cytosol as an unglycosylated species and impair cellular functions.

Hepatitis C virus NS5A colocalizes with the core protein on lipid droplets and interacts with apolipoproteins

The nonstructural protein 5A (NS5A) of the hepatitis C virus (HCV) has been shown to interact with a variety of cellular proteins and implicated in the regulation of cell growth, interferon resistance, and other cellular signaling pathways, but the role of NS5A in HCV pathogenesis has not been firmly established. To further characterize this multifunctional protein, we instigated the studies of the subcellular localization of NS5A in a hepatoma cell line. NS5A was localized to the perinuclear membrane structures, including the endoplasmic reticulum (ER) and the Golgi apparatus, by immunofluorescence staining and confocal microscopy. In addition, it was also associated with the surface of cytoplasmic globular structures when expressed alone or as a part of the NS3-5B polyprotein. Oil red O staining revealed that these globular structures were lipid droplets, where the HCV core protein was also localized. The association of NS5A with intracellular membrane was further confirmed by membrane flotation analysis. To determine whether NS5A interacts with any cellular lipid-binding protein, we performed yeast two-hybrid screening in both HepG2 and human liver cDNA libraries. Apolipoprotein A1 (apoA1), one of the protein components of high-density lipoprotein (HDL) particles, was identified by two independent screening processes. The interaction between NS5A and apoA1 was confirmed by both in vitro pull-down and in vivo coimmunoprecipitation experiments. Immunofluorescence staining revealed a significant colocalization of NS5A and apoA1 in the Golgi apparatus. Our results established an association of NS5A with lipid droplets and apoA1, suggesting that NS5A, together with the core protein, may play a role in the pathogenesis of the derangement of lipid metabolism, contributing to liver steatosis commonly observed in hepatitis C.

Isomer specific syntheses of chlorinated catechols and guaiacols relevant to pulp bleaching

A variety of chlorinated catechols and guaiacols relevant to pulp bleaching were synthesized by employing fundamental differences in the acidities of phenolic hydroxyl groups in chlorinated catechols, and directive effects in guaiacols.

Long-acting beta-agonist treatment in patients with persistent asthma already receiving inhaled corticosteroids

International guidelines recommend that long-acting beta-agonists should be considered in patients who are symptomatic despite moderate doses of inhaled corticosteroids. When combined with inhaled corticosteroids they improve asthma symptoms and lung function and reduce exacerbations. The evidence suggests that they are well tolerated. However, they are less effective than inhaled corticosteroids as monotherapy and should not be used alone, although the addition of a long-acting beta-agonist may permit a small reduction in the corticosteroid dose. Both salmeterol and formoterol appear equally effective in improving asthma control. Formoterol, however, has a rapid onset of action and is now being promoted for the relief of acute asthma symptoms. Both drugs provide prolonged protection against exercise-induced bronchospasm. However, this effect rapidly diminishes with continuous therapy and if this is the main aim of treatment, intermittent use may be preferable. When compared with alternative treatments, inhaled long-acting beta-agonists are more effective in controlling asthma symptoms than either theophylline or antileukotriene agents. Bambuterol, an oral prodrug of terbutaline, appears to be as effective as the inhaled long-acting beta-agonists and has the advantage of once daily oral administration. However, the inhaled long-acting beta-agonists are less likely to have systemic adverse effects. There are theoretical concerns that regular beta-agonist treatment may lead to tolerance and a failure to respond to emergency asthma treatment. While there is no doubt that tolerance occurs, there is currently little evidence that this is a clinical problem. Insights into pharmacological as well as therapeutic interactions between inhaled corticosteroids and beta-agonists are providing justification for their use in combination. Guidelines for the management of patients with chronic persistent asthma are likely to require modification to reflect these developments.