Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 44
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Clin Exp Immunol ; 214(3): 289-295, 2023 12 13.
Article in English | MEDLINE | ID: mdl-37565297

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease of 2019 (COVID-19), has caused havoc around the world. While several COVID-19 vaccines and drugs have been authorized for use, these antiviral drugs remain beyond the reach of most low- and middle-income countries. Rapid viral evolution is reducing the efficacy of vaccines and monoclonal antibodies and contributing to the deaths of some fully vaccinated persons. Others with normal immunity may have chosen not to be vaccinated and remain at risk if they contract the infection. Vaccines may not protect some immunodeficient patients from SARS-CoV-2, who are also at increased risk of chronic COVID-19 infection, a dangerous stalemate between the virus and a suboptimal immune response. Intra-host viral evolution could rapidly lead to the selection and dominance of vaccine and monoclonal antibody-resistant clades of SARS-CoV-2. There is thus an urgent need to develop new treatments for COVID-19. The NZACE2-Patari project, comprising modified soluble angiotensin-converting enzyme 2 (ACE2) molecules, seeks to intercept and block SARS-CoV-2 infection of the respiratory mucosa. In vitro data presented here show that soluble wild-type ACE2 molecules retain the ability to effectively block the Spike (S) glycoprotein of SARS-CoV-2 variants including the ancestral Wuhan, delta (B.1.617.2) and omicron (B.1.1.529) strains. This therapeutic strategy may prove effective if implemented early during the nasal phase of the infection and may act synergistically with other antiviral drugs such as Paxlovid to further mitigate disease severity.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Angiotensin-Converting Enzyme 2 , COVID-19 Vaccines , Peptidyl-Dipeptidase A , Antiviral Agents/therapeutic use , Antiviral Agents/pharmacology , Patient Acuity
2.
J Radiol Prot ; 42(3)2022 08 02.
Article in English | MEDLINE | ID: mdl-35850100

ABSTRACT

With the increasing number and complexity of interventional cardiology procedures, there is the potential for higher occupational radiation doses to the interventionists. In order to reduce the radiation exposure to interventionists, a number of different radiation protection measures can be implemented; the most common of which being personal protective equipment in the form of a lead-equivalent apron. However, significant development has been achieved with mobile lead equivalent radiation protection devices, which provide enhanced radiation protection without the requirement of being directly worn by staff. The RAMPART M1128 radiation protection shield is one of these devices. The dose reduction provided to staff within a Cardiac Catheterisation Laboratory was assessed via the use of electronic personal dosimeters with the Philips live dosimetry system DoseAware (Philips DoseAware). A 60% dose reduction to the primary operator can be achieved with the Rampart device. Further dose reductions are possible for other individuals in the range of 65%-84%. Additionally, dose rate measurements were taken in a simulated clinical set-up using a phantom, which showed that the device provided a 65% dose reduction at eye level and a 90% dose reduction at chest level for the primary operator position. This significant dose reduction means that there is the potential for at least the primary operator to wear a lead apron of reduced lead equivalence specification when the Rampart device is in use, without increasing their occupational exposure and potentially reducing musculoskeletal pain due to the reduced weight.


Subject(s)
Occupational Exposure , Radiation Exposure , Radiation Protection , Drug Tapering , Humans , Occupational Exposure/prevention & control , Radiation Dosage , Radiation Exposure/prevention & control , Radiation Protection/methods
3.
Res Sports Med ; 28(4): 529-539, 2020.
Article in English | MEDLINE | ID: mdl-32602742

ABSTRACT

The present study assessed changes in academy soccer players' perception of mental fatigue (MF) across a competitive season, investigating the relationship between MF and other subjective measures of wellness. Ten players completed a modified Brief Assessment of Mood (BAM+) questionnaire that included the question: "How mentally fatigued do you feel"? on match-day (MD) and one (MD+1), two (MD+2) and three (MD+3) days post-match (35 matches). Players reported their MF, along with other subjective measures (sleep, muscle soreness, fatigue and motivation). Results found MF was elevated on MD+1 (43±1 mm) compared to all other days (all P≤0.001). Players reported lower MF on MD+1 in the late-season phase (34±2 mm) compared to both early- (50±2 mm, P≤0.001) and mid-season (46±2 mm, P≤0.001). This coincided with an 80%-win rate in the late-season phase versus the early- (33%) and mid-season (50%). There were very strong repeated-measures correlations between changes in MF and sleep (r=-0.77), muscle soreness (r=0.94), fatigue (r=0.92) and motivation (r=-0.89; all P ≤ 0.0005). In conclusion, MF was closely aligned to match success and other wellness variables. This data suggests a potential lack of sensitivity for identifying MF using a subjective questionnaire. Therefore, researchers and practitioners could work together to identify other ways of practically assessing MF.


Subject(s)
Competitive Behavior , Mental Fatigue , Soccer/psychology , Athletic Performance/psychology , Humans , Male , Motivation , Myalgia/psychology , Perception , Physical Conditioning, Human , Seasons , Sleep , Soccer/physiology , Time Factors , Young Adult
4.
Hepatology ; 58(4): 1277-86, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23703545

ABSTRACT

UNLABELLED: Given the clinical significance of hepatitis B e antigen (HBeAg) seroconversion in chronic hepatitis B virus (HBV) infection, it is critical to elucidate the mechanisms regulating this process. In the present study, we found that the frequency of circulating chemokine (C-X-C motif) receptor 5 (CXCR5)(+) CD4(+) T cells was higher in patients who had achieved HBeAg seroconversion in both cross-sectional (P < 0.001) and longitudinal (P = 0.009) studies. These cells were able to produce a significantly higher level of intracellular interleukin 21 (IL-21) after stimulation with HBV peptides in patients with telbivudine-induced HBeAg seroconversion (P = 0.007). Furthermore, sorted CXCR5(+) CD4(+) T cells from HBeAg seroconverters boosted a higher frequency of antibody against hepatitis B e antigen (anti-HBe)-secreting B cells in coculture assay (P = 0.011). Of note, the increase in frequency of anti-HBe-secreting B cells was abrogated by soluble recombinant IL-21 receptor-Fc chimera (P = 0.027), whereas exogenous recombinant IL-21 enhanced this effect (P = 0.043). Additionally, circulating CXCR5(+) CD4(+) T cells shared similar phenotypic markers, and were positively correlated in frequency with, splenic follicular T helper cells. CONCLUSION: Circulating CXCR5(+) CD4(+) T cells, by producing IL-21, may have a significant role in facilitating HBeAg seroconversion in patients with chronic HBV infection.


Subject(s)
Antibodies, Viral/blood , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/pathology , Hepatitis B e Antigens/blood , Hepatitis B, Chronic/immunology , Interleukins/metabolism , Receptors, CXCR5/metabolism , Adolescent , Adult , Antiviral Agents/therapeutic use , Biomarkers/blood , CD4-Positive T-Lymphocytes/drug effects , Cells, Cultured , Cross-Sectional Studies , Female , Hepatitis B virus/immunology , Hepatitis B, Chronic/drug therapy , Hepatitis B, Chronic/metabolism , Humans , In Vitro Techniques , Interleukins/pharmacology , Longitudinal Studies , Male , Middle Aged , Phenotype , Recombinant Proteins/pharmacology , Telbivudine , Thymidine/analogs & derivatives , Thymidine/therapeutic use , Young Adult
5.
Int J Sports Physiol Perform ; 18(4): 347-353, 2023 Apr 01.
Article in English | MEDLINE | ID: mdl-36780901

ABSTRACT

PURPOSE: To examine the effects of acute curcumin (CURC) supplementation on recovery from a soccer match in male professional players. METHODS: In a randomized, placebo-controlled, crossover design, 11 players from the under-23 team of an English Premier League club (age 19 [1] y, body mass 79.4 [7.9] kg, height 180.8 [5.7] cm) consumed 500 mg of CURC or a control (medium-chain triglycerides) immediately and 12 and 36 hours after a 90-minute match. Countermovement jump height (CMJ), reactive strength index (RSI), delayed-onset muscle soreness (DOMS, 0-200 mm), and subjective well-being were measured before and 12, 36, and 60 hours postmatch. Global positioning systems measured external load during matches, and dietary intake was recorded across the testing period. RESULTS: External load and dietary intake did not differ between conditions (P ≥ .246). CURC attenuated deficits in CMJ (P ≤ .004) and RSI (P ≤ .001) and reduced DOMS (P ≤ .004) at all postmatch time points (except 60 h post for RSI). The greatest difference between control and CURC was 12 hours post for CMJ (P < .001, 1.91 [4.40] cm, 95% CI, 1.25 to 2.57, g = 0.36) and RSI (P = .003, 0.40 [0.41] AU, 95% CI, 0.17 to 0.63, g = 0.90) and 36 hours post for DOMS (P < .001, 47 [23] mm, 95% CI, -67 to -27, g = 2.12). CONCLUSIONS: CURC intake <36 hours after a soccer match attenuated DOMS and muscle function deficits, suggesting that CURC may aid recovery in professional male soccer players.


Subject(s)
Athletic Performance , Curcumin , Soccer , Adult , Humans , Male , Young Adult , Athletic Performance/physiology , Competitive Behavior/physiology , Muscles , Myalgia/prevention & control , Soccer/physiology , Cross-Over Studies
6.
J Hepatol ; 56(4): 775-81, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22173154

ABSTRACT

BACKGROUND & AIMS: Interleukin-21 (IL-21) stimulates T cell and B cell responses and plays a role in control of chronic viral infections. The role of IL-21 in chronic hepatitis B virus (HBV) infection is not understood. METHODS: Serum IL-21 levels were measured by enzyme immunoassay in 75 HBeAg-positive chronic hepatitis B (CHB) patients undergoing telbivudine treatment. The findings were validated in 103 patients from a separate clinical trial of telbivudine. A complete response to telbivudine was defined as having both HBeAg seroconversion and serum HBV-DNA level <300 copies/ml by treatment week 52. The proportions of T-cells producing IL-21 and/or expressing programmed death 1 (PD-1) in peripheral blood mononuclear cells were assessed longitudinally during treatment by intracellular cytokine staining and flow cytometry. RESULTS: Median serum IL-21 levels at treatment week 12 were significantly higher in patients who did achieve vs. patients who did not achieve a complete response in both the initial (128.4 vs. 69.2 pg/ml, p=0.003) and the validation (142.2 vs. 89.9 pg/ml, p=0.004) trials. Serum levels of IL-21 (p=0.005) or HBV-DNA (p=0.003) levels at treatment week 12 independently predicted HBeAg seroconversion in the first year of treatment. The decrease in PD-1 expression on CD4(+) and CD8(+) T cells during the first 12 weeks on telbivudine treatment was not correlated with changes in IL-21 concentrations. CONCLUSIONS: Serum IL-21 levels may be a biomarker for HBeAg seroconversion, and may contribute to individualization of antiviral therapy in HBeAg-positive CHB. IL-21 may also have a role in immunotherapy for CHB.


Subject(s)
Antiviral Agents/therapeutic use , Hepatitis B e Antigens/blood , Hepatitis B, Chronic/drug therapy , Hepatitis B, Chronic/immunology , Interleukins/blood , Nucleosides/therapeutic use , Pyrimidinones/therapeutic use , Adult , Alanine Transaminase/blood , Biomarkers/blood , DNA, Viral/blood , Disease Progression , Female , Hepatitis B virus/genetics , Hepatitis B, Chronic/diagnosis , Humans , Male , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness Index , Telbivudine , Thymidine/analogs & derivatives , Treatment Outcome
7.
Antimicrob Agents Chemother ; 55(2): 888-94, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21098256

ABSTRACT

An increased CD8(+) T cell response to hepatitis B virus (HBV) peptides occurs between 12 and 24 weeks after starting antiviral therapy for chronic hepatitis B. It is not known whether these cells have antiviral function. The aim of this study was to determine whether clonal expansions of CD8(+) T cells at these time points predict the virological response to therapy. Peripheral blood CD8(+) T cells were obtained from 20 patients treated with lamivudine or telbivudine for chronic hepatitis B at baseline, 12 weeks, and 24 weeks. The CDR3 spectratype of each T cell receptor (TCR) ß chain variable region (Vß) gene family was analyzed, and the changes in the numbers of Vß families with clonal expansions were compared in subjects with (n = 12) and without (n = 8) a virological response (52 week HBV DNA < 300 copies/ml). The number of CD8(+) TCR Vß families with clonal expansions at 12 weeks relative to baseline (median [10th to 90th percentile], +2.5 [0 to +7] versus +1 [0 to +2], P = 0.03) and at 24 weeks relative to 12 weeks (+1 [0 to +2] versus -1 [-3 to +4], P = 0.006) was higher in subjects with a virological response versus subjects without a virological response, as were interleukin-2 (IL-2) but not IL-21 mRNA levels in peripheral blood mononuclear cells. The duration of new expansions at 12 weeks was higher (P < 0.0001) in responders. Increased numbers of CD8(+) T cell expansions after antiviral therapy are associated with a virological response to treatment. These CD8(+) T cells are a potential target for a therapeutic vaccine for chronic hepatitis B.


Subject(s)
Antiviral Agents/therapeutic use , CD8-Positive T-Lymphocytes/immunology , Complementarity Determining Regions/genetics , Hepatitis B, Chronic/immunology , Lamivudine/therapeutic use , Nucleosides/therapeutic use , Pyrimidinones/therapeutic use , Receptors, Antigen, T-Cell, alpha-beta/genetics , Adult , Double-Blind Method , Female , Hepatitis B virus/drug effects , Hepatitis B virus/genetics , Hepatitis B, Chronic/drug therapy , Hepatitis B, Chronic/virology , Humans , Lymphocyte Activation/immunology , Male , Polymerase Chain Reaction/methods , Receptors, Antigen, T-Cell, alpha-beta/chemistry , Receptors, Antigen, T-Cell, alpha-beta/metabolism , Telbivudine , Thymidine/analogs & derivatives , Treatment Outcome , Young Adult
8.
J Gen Virol ; 92(Pt 8): 1800-1808, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21508187

ABSTRACT

The mechanisms underlying the high levels of hepatitis B virus (HBV) replication that cause hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (e-CHB) are unknown. Impaired anti-HBV immunity, which may be measurable as a relaxation of selection pressure on the virus, is possible. A group of Tongans (n = 345) with a chronic HBV infection, including seven with e-CHB, were genotyped at HLA class I. The repertoire of HBV core-gene codons under positive selection pressure was defined by phylogenetic analysis (by using the paml program) of 708 cloned sequences extracted from the 67 of these 345 subjects with the same repertoire of HLA class I alleles as the seven e-CHB individuals and matched controls (see below). The frequency of non-synonymous mutations at these codons was measured in longitudinal data from 15 subjects. Finally, the number of non-synonymous mutations at these codons was compared in seven groups comprised of one subject with e-CHB and 1-3 HLA class I-matched controls with an inactive, HBeAg-negative chronic HBV infection (e-InD). Nineteen codons in the core gene were under positive selection pressure. There was a high frequency of new non-synonymous mutations at these codons (P<0.0001) in longitudinal data. The mean number of these 19 codons with non-synonymous mutations was lower (P = 0.02) in HBV from subjects with e-CHB (4.4±0.5 codons per subject) versus those with e-InD (6.4±0.4 codons per subject). There is a subtle relaxation in selection pressure on the HBV core gene in e-CHB. This may be due to impaired antiviral immunity, and could contribute to the high levels of viral replication that cause liver inflammation in this disease.


Subject(s)
Hepatitis B Core Antigens/genetics , Hepatitis B e Antigens/genetics , Hepatitis B virus/genetics , Hepatitis B, Chronic/virology , Selection, Genetic , Adult , Amino Acid Sequence , Female , Hepatitis B Core Antigens/metabolism , Hepatitis B e Antigens/metabolism , Hepatitis B virus/classification , Hepatitis B virus/isolation & purification , Hepatitis B virus/physiology , Humans , Male , Middle Aged , Molecular Sequence Data , Mutation , Phylogeny
9.
J Virol ; 84(1): 621-9, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19846510

ABSTRACT

The full repertoire of hepatitis B virus (HBV) peptides that bind to the common HLA class I molecules found in areas with a high prevalence of chronic HBV infection has not been determined. This information may be useful for designing immunotherapies for chronic hepatitis B. We identified amino acid residues under positive selection pressure in the HBV core gene by phylogenetic analysis of cloned DNA sequences obtained from HBV DNA extracted from the sera of Tongan subjects with inactive, HBeAg-negative chronic HBV infections. The repertoires of positively selected sites in groups of subjects who were homozygous for either HLA-B*4001 (n = 10) or HLA-B*5602 (n = 7) were compared. We identified 13 amino acid sites under positive selection pressure. A significant association between an HLA class I allele and the presence of nonsynonymous mutations was found at five of these sites. HLA-B*4001 was associated with mutations at E77 (P = 0.05) and E113 (P = 0.002), and HLA-B*5602 was associated with mutations at S21 (P = 0.02). In addition, amino acid mutations at V13 (P = 0.03) and E14 (P = 0.01) were more common in the seven subjects with an HLA-A*02 allele. In summary, we have developed an assay that can identify associations between HLA class I alleles and HBV core gene amino acids that mutate in response to selection pressure. This is consistent with published evidence that CD8(+) T cells have a role in suppressing viral replication in inactive, HBeAg-negative chronic HBV infection. This assay may be useful for identifying the clinically significant HBV peptides that bind to common HLA class I molecules.


Subject(s)
Hepatitis B virus/genetics , Histocompatibility Antigens Class I/genetics , Immune Evasion/genetics , Mutation , Alleles , HLA-A Antigens/genetics , HLA-B Antigens/genetics , Hepatitis B/epidemiology , Hepatitis B/genetics , Hepatitis B/immunology , Hepatitis B virus/immunology , Histocompatibility Antigens Class I/metabolism , Humans , New Zealand/epidemiology , Peptide Fragments/immunology , Peptide Fragments/metabolism , Selection, Genetic , Tonga/epidemiology , Viral Core Proteins/genetics , Viral Core Proteins/immunology
10.
J Med Virol ; 83(2): 218-24, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21181915

ABSTRACT

Although it is widely believed that cytotoxic T lymphocytes (CTL) are responsible for severe flares of chronic hepatitis B that lead to liver failure, the published evidence to support this hypothesis is weak. The frequency of the I27V mutation in the HBV core gene, which produces a core 18-27 peptide capable of binding HLA-A*02, was compared in Chinese patients with severe liver inflammation (n = 77, including 39 with acute-on-chronic liver failure), moderate liver inflammation (n = 44) and inactive disease (n = 45). The frequency with which V27 reverted to the wild-type I27 was compared in severe liver inflammation patients who were either HLA-A*02 positive (n = 5) or negative (n = 5). The frequency of patients with a V27 positive HBV was higher in severe than in moderate liver inflammation (23.4% vs. 6.8%, P = 0.02) or inactive disease (23.4% vs. 4.7%, P = 0.006). After a minimum of 3 months follow-up, the frequency of reversion of V27 to the wild-type I27 was higher in HLA-A*02 positive than negative patients (5/5 vs. 1/5, P = 0.05). In summary, this is the first data showing an association between a specific amino acid mutation (I27V) and severe liver inflammation in patients with chronic hepatitis B. This mutation would produce a peptide that is known to bind HLA-A*02 and stimulate CTL. The high frequency of reversion to wild-type I27 in HLA-A*02 positive subjects suggests that CTL recognizing this peptide exist, and is consistent with the possibility that they contribute to the pathophysiology of severe liver inflammation in chronic hepatitis B.


Subject(s)
Hepatitis B Core Antigens/genetics , Hepatitis B virus/genetics , Hepatitis B, Chronic/pathology , Hepatitis B, Chronic/virology , Adult , Asian People/genetics , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Cells, Cultured , Female , Gene Frequency , HLA-A Antigens/immunology , HLA-A2 Antigen , Hepatitis B Core Antigens/metabolism , Hepatitis B virus/pathogenicity , Hepatitis B, Chronic/immunology , Host-Pathogen Interactions/genetics , Humans , Male , Mutation , Severity of Illness Index , T-Lymphocytes, Cytotoxic/immunology , T-Lymphocytes, Cytotoxic/metabolism , Valine/genetics
11.
J Med Virol ; 83(9): 1544-50, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21739444

ABSTRACT

The existence of statistical associations between hepatitis B-related acute-on-chronic liver failure and both hepatitis B virus (HBV) genotype and mutations in the basal core promoter (BCP) and precore (PC) regions needs to be confirmed. A total of 322 patients with a chronic HBV infection, including 77 with hepatitis B-related acute-on-chronic liver failure, 109 with hepatocellular carcinoma (HCC) and 136 with chronic hepatitis B (CHB) were enrolled. The HBV genotype and the presence of mutations in the BCP/PC regions were determined by direct sequencing, and the frequencies were compared in the three patient groups. Overall, 198/322 (61.5%) were infected with genotype B and 124/322 (38.5%) with genotype C. Genotype B was significantly more frequent in patients with acute-on-chronic liver failure than CHB (92.2% vs. 60.3%, P < 0.001). As a contrast, genotype C was more common in patients with HCC than CHB (58.7% vs. 39.7%, P = 0.003). In genotype B patients, the A1762T/G1764A, A1846T, and G1896A mutations were significantly more prevalent in patients with acute-on-chronic liver failure than CHB (50.7% vs. 28.0%, P = 0.004; 59.2% vs. 34.1%, P = 0.002; 69.0% vs. 41.5%, P = 0.001, respectively). In multivariate analysis, the risk factors for acute-on-chronic liver failure were genotype B, A1762T/G1764A, and G1896A. In conclusion, CHB patients with genotype B, G1896A, and A1762T/G1764A had a higher tendency to develop liver failure than patients with genotype C. Therefore, HBV genotyping and detecting G1896A and A1762T/G1764A mutations might have important clinical implications as predictive risk factors for hepatitis B-related acute-on-chronic liver failure.


Subject(s)
End Stage Liver Disease/virology , Hepatitis B virus/genetics , Hepatitis B/virology , Liver Failure, Acute/virology , Adult , Aged , Base Sequence , DNA, Viral/genetics , Female , Genotype , Hepatitis B/pathology , Hepatitis B/physiopathology , Hepatitis B Core Antigens/genetics , Hepatitis B e Antigens/blood , Hepatitis B e Antigens/immunology , Hepatitis B virus/pathogenicity , Humans , Male , Middle Aged , Mutation , Polymerase Chain Reaction , Polymorphism, Single Nucleotide , Prevalence , Promoter Regions, Genetic , Risk Factors , Sequence Analysis, DNA
12.
Hepatology ; 51(6): 1933-44, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20512987

ABSTRACT

UNLABELLED: Although threshold levels for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) titers have recently been proposed to guide therapy for chronic hepatitis B (CHB), their relationship to circulating hepatitis B virus (HBV) DNA and intrahepatic HBV replicative intermediates, and the significance of emerging viral variants, remains unclear. We therefore tested the hypothesis that HBsAg and HBeAg titers may vary independently of viral replication in vivo. In all, 149 treatment-naïve CHB patients were recruited (HBeAg-positive, n = 71; HBeAg-negative, n = 78). Quantification of HBeAg and HBsAg was performed by enzyme immunoassay. Virological characterization included serum HBV DNA load, HBV genotype, basal core promoter (BCP)/precore (PC) sequence, and, in a subset (n = 44), measurement of intrahepatic covalently closed circular DNA (cccDNA) and total HBV DNA, as well as quantitative immunohistochemical (IHC) staining for HBsAg. In HBeAg-positive CHB, HBsAg was positively correlated with serum HBV DNA and intrahepatic cccDNA and total HBV DNA (r = 0.69, 0.71, 0.76, P < 0.01). HBeAg correlated with serum HBV DNA (r = 0.60, P < 0.0001), although emerging BCP/PC variants reduced HBeAg titer independent of viral replication. In HBeAg-negative CHB, HBsAg correlated poorly with serum HBV DNA (r = 0.28, P = 0.01) and did not correlate with intrahepatic cccDNA nor total HBV DNA. Quantitative IHC for hepatocyte HBsAg confirmed a relationship with viral replication only in HBeAg-positive patients. CONCLUSION: The correlation between quantitative HBsAg titer and serum and intrahepatic markers of HBV replication differs between patients with HBeAg-positive and HBeAg-negative CHB. HBeAg titers may fall independent of viral replication as HBeAg-defective variants emerge prior to HBeAg seroconversion. These findings provide new insights into viral pathogenesis and have practical implications for the use of quantitative serology as a clinical biomarker.


Subject(s)
Hepatitis B Surface Antigens/blood , Hepatitis B e Antigens/blood , Hepatitis B, Chronic/virology , Viral Load , Virus Replication , Adult , Biomarkers/blood , Female , Hepatitis B, Chronic/immunology , Humans , Immunohistochemistry , Liver/virology , Male , Middle Aged
13.
Virol J ; 8: 69, 2011 Feb 14.
Article in English | MEDLINE | ID: mdl-21320337

ABSTRACT

BACKGROUND: The mechanisms by which chronic hepatitis B is completely resolved through antiviral therapy are unknown, and the contribution of acquired T cell immunity to hepatitis B surface antigen (HBsAg) seroclearance has not been investigated. Therefore, we measured the T-cell responses to core and envelope antigens in patients with HBsAg seroclearance. METHODS: Fourteen subjects with HBsAg seroclearance following antiviral treatment for chronic hepatitis B, 7 HBeAg-positive immunotolerant HBV carriers and 9 HBeAg-negative inactive HBsAg carriers were recruited. HBV-specific T-cell responses to recombinant HBV core (rHBcAg) and envelope (rHBsAg) proteins and pools of core and envelope peptides were measured using an ELISPOT assay detecting interferon-gamma and intracellular cytokine staining (ICS) assays detecting interferon-gamma or interleukin 2. RESULTS: Interferon-gamma ELISPOT assays showed a low frequency of weak responses to the rHBsAg and S peptide pool in the HBsAg seroclearance group, and the response frequency to the rHBcAg and the C peptide pool was higher than to the rHBsAg (P < 0.001) and S peptide pool (P = 0.001) respectively. A higher response frequency to C than S peptide pools was confirmed in the interferon-gamma ICS assays for both CD4+ (P = 0.033) and CD8+ (P = 0.040) T cells in the HBsAg seroclearance group. The responses to C and S antigens in the inactive carriers were similar. CONCLUSIONS: There was a low frequency of CD4+ and CD8+ T cell immune responses to envelope antigens in Chinese subjects with HBsAg seroclearance following antiviral therapy. It is unlikely that these immune responses are responsible for HBsAg seroclearance in these subjects.


Subject(s)
Antiviral Agents/administration & dosage , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Hepatitis B Surface Antigens/blood , Hepatitis B virus/immunology , Hepatitis B/drug therapy , Adult , Female , Hepatitis B Core Antigens/immunology , Humans , Interferon-gamma/metabolism , Interleukin-2/biosynthesis , Male , Middle Aged , Viral Envelope Proteins/immunology
14.
Expert Rev Clin Immunol ; 17(6): 553-560, 2021 06.
Article in English | MEDLINE | ID: mdl-33792473

ABSTRACT

Background: COVID-19 has caused calamitous health, economic and societal consequences globally. Currently, there is no effective treatment for the infection. Areas covered: We have recently described the NZACE2-Patari project, which seeks to administer modified Angiotensin Converting Enzyme 2 (ACE2) molecules early in the infection to intercept and block SARS-CoV-2 binding to the pulmonary epithelium. Expert opinion: Since the nasopharyngeal mucosa is infected in the first asymptomatic phase of the infection, treatment of the nose is likely to be safe and potentially effective. The intercepted virus will be swallowed and destroyed in the stomach. There is however a limited window of opportunity to alter the trajectory of the infection in an individual patient, which requires access to rapid testing for SARS-CoV-2. The proposed strategy is analogous to passive immunization of viral infections such as measles and may be of particular benefit to immunodeficient and unvaccinated individuals.


Subject(s)
Angiotensin-Converting Enzyme 2/administration & dosage , Antiviral Agents/administration & dosage , COVID-19 Drug Treatment , Nasopharynx/virology , Respiratory Mucosa/virology , SARS-CoV-2/drug effects , Stomach/virology , Administration, Intranasal , COVID-19/enzymology , COVID-19/virology , Host-Pathogen Interactions , Humans , SARS-CoV-2/pathogenicity , Treatment Outcome
15.
ACS Appl Mater Interfaces ; 12(11): 13503-13509, 2020 Mar 18.
Article in English | MEDLINE | ID: mdl-32096978

ABSTRACT

If thermoplasmonic applications such as heat-assisted magnetic recording are to be commercially viable, it is necessary to optimize both thermal stability and plasmonic performance of the devices involved. In this work, a variety of different adhesion layers were investigated for their ability to reduce dewetting of sputtered 50 nm Au films on SiO2 substrates. Traditional adhesion layer metals Ti and Cr were compared with alternative materials of Al, Ta, and W. Film dewetting was shown to increase when the adhesion material diffuses through the Au layer. An adhesion layer thickness of 0.5 nm resulted in superior thermomechanical stability for all adhesion metals, with an enhancement factor of up to 200× over 5 nm thick analogues. The metals were ranked by their effectiveness in inhibiting dewetting, starting with the most effective, in the order Ta > Ti > W > Cr > Al. Finally, the Au surface-plasmon polariton response was compared for each adhesion layer, and it was found that 0.5 nm adhesion layers produced the best response, with W being the optimal adhesion layer material for plasmonic performance.

16.
N Z Med J ; 133(1515): 112-118, 2020 05 22.
Article in English | MEDLINE | ID: mdl-32438383

ABSTRACT

COVID-19 is a new zoonotic disease caused by the SARS-CoV-2 virus. Since its emergence in Wuhan City, China, the virus has rapidly spread across the globe causing calamitous health, economic and societal consequences. It causes disproportionately severe disease in the elderly and those with co-morbidities, such as hypertension and diabetes. There is currently no proven treatment for COVID-19 and a safe and effective vaccine is at least a year away. The virus gains access to the respiratory epithelium through cell surface angiotensin converting enzyme 2 (ACE2). The receptor binding domain (RBD) of the virus is unlikely to mutate without loss of pathogenicity and thus represents an attractive target for antiviral treatment. Inhaled modified recombinant human ACE2, may bind SARS-CoV-2 and mitigate lung damage. This decoy strategy is unlikely to provoke an adverse immune response and may reduce morbidity and mortality in high-risk groups.


Subject(s)
Administration, Inhalation , Coronavirus Infections/drug therapy , Peptidyl-Dipeptidase A/therapeutic use , Pneumonia, Viral/drug therapy , Angiotensin-Converting Enzyme 2 , Betacoronavirus , COVID-19 , Humans , Lung/virology , Pandemics , Peptidyl-Dipeptidase A/administration & dosage , Protein Binding , Recombinant Proteins/administration & dosage , Recombinant Proteins/therapeutic use , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , COVID-19 Drug Treatment
17.
Int J Sports Physiol Perform ; 14(3): 385-391, 2019 Mar 01.
Article in English | MEDLINE | ID: mdl-30204517

ABSTRACT

PURPOSE: To examine whether consuming casein protein (CP) before sleep would enhance recovery after a nighttime soccer match in professional players. METHODS: In a randomized, crossover design, 10 professional soccer players from the reserve squad of a team in the highest tier of English soccer consumed 40 g of CP or 40 g of carbohydrates (CON) 30 min presleep after a soccer match (kick off: 7 PM). To assess recovery, countermovement-jump height, reactive strength index, muscle soreness, and the adapted Brief Assessment of Mood (BAM+) Questionnaire were measured before and 12, 36, and 60 h after each match. Dietary intake across the testing period was also recorded. RESULTS: There were unclear differences in external load in the matches and dietary intake between CON and CP. Casein protein had a most likely and likely beneficial effect on countermovement-jump recovery at 12 and 36 h postmatch (CP -1.6; ±1.2% vs CON -6.6; ±1.7%; -4.1; ±2.3% vs -0.4; ±1.1%, respectively). Reactive strength index recovery was most likely enhanced with CP at 12 and 36 h postmatch, and muscle soreness, as measured with a visual analog scale (in millimeters), was most likely greater in CON versus CP at 12 h postmatch (72; ±17 vs 42; ±20 mm). BAM+ was possibly lower in CON at 36 h postmatch but unaffected at other time points. CONCLUSIONS: Presleep CP accelerates functional recovery in professional soccer players and, therefore, provides a practical means of attenuating performance deficits in the days after a match.


Subject(s)
Caseins/administration & dosage , Muscle Strength/physiology , Myalgia/prevention & control , Sleep , Soccer/injuries , Affect , Competitive Behavior/physiology , Cross-Over Studies , Humans , Male , Recovery of Function , Single-Blind Method , Sleep/physiology , Soccer/physiology , Soccer/psychology , Young Adult
18.
ACS Appl Mater Interfaces ; 11(7): 7607-7614, 2019 Feb 20.
Article in English | MEDLINE | ID: mdl-30682242

ABSTRACT

The use of a metallic adhesion layer is known to increase the thermo-mechanical stability of Au thin films against solid-state dewetting, but in turn results in damping of the plasmonic response, reducing their utility in applications such as heat-assisted magnetic recording (HAMR). In this work, 50 nm Au films with Ti adhesion layers ranging in thickness from 0 to 5 nm were fabricated, and their thermal stability, electrical resistivity, and plasmonic response were measured. Subnanometer adhesion layers are demonstrated to significantly increase the stability of the thin films against dewetting at elevated temperatures (>200 °C), compared to more commonly used adhesion layer thicknesses that are in the range of 2-5 nm. For adhesion layers thicker than 1 nm, the diffusion of excess Ti through Au grain boundaries and subsequent oxidation was determined to result in degradation of the film. This mechanism was confirmed using transmission electron microscopy and X-ray photoelectron spectroscopy on annealed 0.5 and 5 nm adhesion layer samples. The superiority of subnanometer adhesion layers was further demonstrated through measurements of the surface-plasmon polariton resonance; those with thinner adhesion layers possessed both a stronger and spectrally sharper resonance. These results have relevance beyond HAMR to all Ti/Au systems operating at elevated temperatures.

19.
Antiviral Res ; 75(1): 36-42, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17210188

ABSTRACT

BACKGROUND/AIM: An understanding of ribavirin's beneficial effects on treatment outcome in chronic hepatitis C (CH-C) may help to develop new treatment approaches. Here we investigated whether ribavirin directly affects HCV-specific reactivity of CD4+T-lymphocytes from patients with CH-C. METHODS: Peripheral blood mononuclear cells from forty HCV RNA positive patients were cultured ex vivo with HCV core, NS3, NS4 alone, and with different concentrations of ribavirin. Virus-specific CD4+ T-cell reactivity was analysed by a proliferation assay; quantitation of cytokine (interferon-gamma, IL-10, IL-5, IL-12p35, IL-12p40) mRNA levels; measurement of interferon-gamma and IL-10 production (by ELISA) and enumeration of interferon-gamma and IL-10 producing T-cells by Elispot assays. RESULTS: At 2-5 microM ribavirin induced de novo or enhanced T-cell proliferation to HCV antigens in a proportion of patients. Increased T-cell proliferation was associated with decreased IL-10 production in response to HCV core and reduced frequency of IL-10 producing CD4+ T-cells, while interferon-gamma levels remained unchanged. At 20 microM ribavirin markedly suppressed T-cell proliferation, and interferon-gamma mRNA expression to HCV antigens. CONCLUSIONS: Ribavirin, at clinically achievable plasma levels, modulates directly the T-cell responses to HCV antigens in some CH-C patients. Suppression of IL-10 production may represent a useful strategy to induce/augment T-cell reactivity to HCV.


Subject(s)
Antiviral Agents/therapeutic use , Hepacivirus/drug effects , Hepatitis C, Chronic/drug therapy , Ribavirin/therapeutic use , T-Lymphocytes/drug effects , CD4-Positive T-Lymphocytes/drug effects , Cell Division/drug effects , Cells, Cultured , Cytokines/analysis , Cytokines/genetics , Cytokines/metabolism , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay , Gene Expression , Hepatitis C Antigens/blood , Humans , Interferon-gamma/analysis , Interferon-gamma/biosynthesis , Interleukin-10/analysis , Interleukin-10/biosynthesis , Peptide Fragments/metabolism , RNA, Messenger/analysis , RNA, Viral/genetics , T-Lymphocytes/physiology , Viral Core Proteins/metabolism , Viral Nonstructural Proteins/metabolism
20.
J Am Coll Surg ; 204(6): 1115-26, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17544070

ABSTRACT

BACKGROUND: In response to a Congressional mandate to compare risk-adjusted surgical outcomes from Department of Veterans Affairs (VA) hospitals with those from private-sector hospitals, the National Surgical Quality Improvement Program was initiated in the VA system and then was developed in a select group of university medical centers in the private sector. This article analyzes risk-adjusted outcomes after vascular surgical operations in men performed at VA hospitals as compared with private-sector hospitals. STUDY DESIGN: This is a prospective cohort study of a sample of vascular surgical operations in men performed at 128 VA medical centers as compared with 14 university medical centers from October 1, 2001 to September 30, 2004. Patient and operative characteristics, and both unadjusted and risk-adjusted 30-day postoperative morbidity and mortality outcomes were compared. RESULTS: Data from 30,058 vascular operations in men at VA hospitals were compared with 5,174 cases performed at private-sector hospitals. The unadjusted 30-day mortality rate was notably lower in the VA system as compared with the private-sector group (3.4% versus 4.2%, p = 0.004). After risk-adjustment, there was no marked difference in mortality between the two hospital types. The unadjusted 30-day morbidity rate was also considerably lower in the VA hospitals as compared with the private sector (17.3% versus 22.3%, p < 0.0001). After risk-adjustment, morbidity in the VA system remained considerably lower than in the private sector, with an odds ratio of 0.84 (95% CI, 0.78 to 0.92). CONCLUSIONS: In vascular surgical operations in men, the VA hospitals demonstrated a lower risk-adjusted 30-day morbidity rate than the private-sector group. There is no marked difference in adjusted mortality rates between the two types of institutions.


Subject(s)
Academic Medical Centers , Hospitals, Veterans , Postoperative Complications/epidemiology , Vascular Surgical Procedures/mortality , Academic Medical Centers/standards , Aged , Cohort Studies , Hospitals, Veterans/standards , Humans , Male , Morbidity , Postoperative Complications/mortality , Private Sector , Prospective Studies , Safety , United States/epidemiology
SELECTION OF CITATIONS
SEARCH DETAIL