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Biomedical subjects

Peter Hayes

Publications and source records attributed to Peter Hayes.

13 recordsLinked to original sources
PubMed2006

The putative use of alpha-1-acid glycoprotein as a non-invasive marker of fibrosis.

The acute phase response to injury or infection results in alterations in the expression of the plasma proteins produced by the liver. Many of these biomolecules are glycosylated with oligosaccharide chains covalently attached to the polypeptide backbone and the extent and composition of this glycosylation can be altered in a disease-dependent manner. Of particular interest is the observation that the acute phase glycoprotein, alpha-1-acid glycoprotein (AGP) has altered glycosylation in several physiological and pathological conditions. It is posited that changes induced in liver diseases may reflect disease severity and may therefore act as a non-invasive marker of fibrosis. This study has investigated the glycosylation of AGP in the plasma of people with varying degrees of cirrhosis and fibrosis. Hyperfucosylation was observed in all disease samples in comparison to normal plasma and was significantly increased in cirrhosis. Both sialic acid and N-acetylgalactosamine (GalNAc) were negatively associated with fibrosis. Two samples were found to express GalNAc, which as a constituent of the glycosylation of serum proteins is rare. In conclusion, fucose, sialic acid and other aspects of the glycosylation of AGP are influenced by the degree of fibrosis and as such may prove a valuable prognostic indicator of the development of cirrhosis.

Acetylgalactosamine↗
PubMed2006

Hyaluronic acid predicts hepatic fibrosis in children with hepatic disease.

BACKGROUND: Hyaluronic acid (HA) is removed by the liver via sinusoidal cell adhesion molecules. This is impeded in fibrosis, leading to a rise in serum HA. As a noninvasive marker of fibrosis, HA may obviate the need for liver biopsy. OBJECTIVE: To evaluate HA as a marker of hepatic fibrosis, in unselected children undergoing liver biopsy. METHODS: Ninety-three unselected consecutive children (median age, 7.5 years; range, 0.07-19 years) undergoing a liver biopsy between April 2003 and March 2004 were prospectively recruited. Liver biopsy and fasting HA levels were taken simultaneously. The Ishak score was used to stage fibrosis. Scores of 3 or greater were regarded as significant fibrosis. Hyaluronic acid levels were measured using an enzyme-linked binding protein assay (2002 Corgenix, Inc) (adult reference range, 0-75 ng/mL; pediatric reference range, 0-30 ng/mL). RESULTS: Twenty-three (25%) of 93 biopsies had significant fibrosis, and HA levels in this group were significantly higher than those with mild fibrosis (Ishak score, <3), (median level, 72 ng/mL vs 30 ng/mL; Mann-Whitney U test; P < 0.005). Hyaluronic acid level of 50 ng/mL had a positive predictive value 40% and negative predictive value 86% for significant fibrosis. An HA level 200 ng/mL has a sensitivity of 26% and specificity of 90%. CONCLUSIONS: Hyaluronic Acid is a valid noninvasive predictor of hepatic fibrosis in unselected children with liver disease. An HA level of 200 ng/mL strongly suggests significant fibrosis. Hyaluronic acid level of less than 50 ng/mL accurately identifies those who do not have significant fibrosis.

Adolescent↗
PubMed2006

Induction of multifunctional human immunodeficiency virus type 1 (HIV-1)-specific T cells capable of proliferation in healthy subjects by using a prime-boost regimen of DNA- and modified vaccinia virus Ankara-vectored vaccines expressing HIV-1 Gag coupled to CD8+ T-cell epitopes.

A double-blind randomized phase I trial was conducted in human immunodeficiency virus type 1 (HIV-1)-negative subjects receiving vaccines vectored by plasmid DNA and modified vaccinia virus Ankara (MVA) expressing HIV-1 p24/p17 gag linked to a string of CD8(+) T-cell epitopes. The trial had two groups. One group received either two doses of MVA.HIVA (2x MVA.HIVA) (n=8) or two doses of placebo (2x placebo) (n=4). The second group received 2x pTHr.HIVA followed by one dose of MVA.HIVA (n=8) or 3x placebo (n=4). In the pTHr.HIVA-MVA.HIVA group, HIV-1-specific T-cell responses peaked 1 week after MVA.HIVA vaccination in both ex vivo gamma interferon (IFN-gamma) ELISPOT (group mean, 210 spot-forming cells/10(6) cells) and proliferation (group mean stimulation index, 37), with assays detecting positive responses in four out of eight and five out of eight subjects, respectively. No HIV-1-specific T-cell responses were detected in either assay in the 2x MVA.HIVA group or subjects receiving placebo. Using a highly sensitive and reproducible cultured IFN-gamma ELISPOT assay, positive responses mainly mediated by CD4(+) T cells were detected in eight out of eight vaccinees in the pTHr.HIVA-MVA.HIVA group and four out of eight vaccinees in the 2x MVA.HIVA group. Importantly, no false-positive responses were detected in the eight subjects receiving placebo. Of the 12 responders, 11 developed responses to previously identified immunodominant CD4(+) T-cell epitopes, with 6 volunteers having responses to more than one epitope. Five out of 12 responders also developed CD8(+) T-cell responses to the epitope string. Induced T cells produced a variety of anti-viral cytokines, including tumor necrosis factor alpha and macrophage inflammatory protein 1 beta. These data demonstrate that prime-boost vaccination with recombinant DNA and MVA vectors can induce multifunctional HIV-1-specific T cells in the majority of vaccinees.

AIDS Vaccines↗
PubMed2005

Standardization of cytokine flow cytometry assays.

BACKGROUND: Cytokine flow cytometry (CFC) or intracellular cytokine staining (ICS) can quantitate antigen-specific T cell responses in settings such as experimental vaccination. Standardization of ICS among laboratories performing vaccine studies would provide a common platform by which to compare the immunogenicity of different vaccine candidates across multiple international organizations conducting clinical trials. As such, a study was carried out among several laboratories involved in HIV clinical trials, to define the inter-lab precision of ICS using various sample types, and using a common protocol for each experiment (see additional files online). RESULTS: Three sample types (activated, fixed, and frozen whole blood; fresh whole blood; and cryopreserved PBMC) were shipped to various sites, where ICS assays using cytomegalovirus (CMV) pp65 peptide mix or control antigens were performed in parallel in 96-well plates. For one experiment, antigens and antibody cocktails were lyophilised into 96-well plates to simplify and standardize the assay setup. Results ((CD4+)cytokine+ cells and (CD8+)cytokine+ cells) were determined by each site. Raw data were also sent to a central site for batch analysis with a dynamic gating template. Mean inter-laboratory coefficient of variation (C.V.) ranged from 17-44% depending upon the sample type and analysis method. Cryopreserved peripheral blood mononuclear cells (PBMC) yielded lower inter-lab C.V.'s than whole blood. Centralized analysis (using a dynamic gating template) reduced the inter-lab C.V. by 5-20%, depending upon the experiment. The inter-lab C.V. was lowest (18-24%) for samples with a mean of > 0.5% IFNgamma + T cells, and highest (57-82%) for samples with a mean of < 0.1% IFNgamma + cells. CONCLUSION: ICS assays can be performed by multiple laboratories using a common protocol with good inter-laboratory precision, which improves as the frequency of responding cells increases. Cryopreserved PBMC may yield slightly more consistent results than shipped whole blood. Analysis, particularly gating, is a significant source of variability, and can be reduced by centralized analysis and/or use of a standardized dynamic gating template. Use of pre-aliquoted lyophilized reagents for stimulation and staining can provide further standardization to these assays.

Blood Preservation↗
PubMed2005

Comprehensive clinical care on-site in men-only saunas: confidential STI/HIV screening outreach clinic.

During 2001 and 2002 an anonymous outreach-screening programme in Melbourne, Australia, offered testing for gonorrhoea and chlamydia on-site at men-only saunas. Modifications were made to this screening programme to offer a comprehensive testing clinic for sexually transmissible infections (STIs), including HIV. The comprehensive clinic was evaluated after one year of operation, and comparisons were made with the earlier anonymous screening programme. The comprehensive outreach clinic made contact with fewer men (n = 557), however, men tested had a higher prevalence of gonorrhoea and chlamydia (17%), and all men tested positive for STIs/HIV were followed up. The findings and comparisons outlined in this paper may be used for different communities to decide what screening programme model best suits their individual situation: anonymous programme with fewer tests offered, confidential and comprehensive STI/HIV testing programme, or both. On the basis of our evaluation, we have opted to continue the comprehensive STI/HIV testing programme in local men-only saunas.

Adult↗
PubMed2004

Management of hepatitis C.

Hepatitis C virus (HCV) infection is a common cause of chronic liver disease and hepatocellular carcinoma. It is estimated that 15-20% of those infected will develop cirrhosis after 20 years of infection. It is transmitted parenterally, and HCV antibody and HCV RNA tests diagnose infection with a high degree of accuracy. Currently, a combination of peginterferon and ribavirin is the most efficacious treatment, with sustained viral response rates of 45% for genotype 1 and 80% for genotypes 2 and 3. There is some evidence that treatment with interferon-based regimens can improve the natural history of this infection. The side effects of treatment are well recognized and include leucopenia, thrombocytopenia, haemolytic anaemia and depression. Patients with HCV-related decompensated cirrhosis and/or hepatocellular carcinoma should be considered for liver transplantation. The management of special groups, including those with acute HCV infection, co-infected with hepatitis B (HBV) or human immunodeficiency virus (HIV), continues to be defined.

Antiviral Agents↗
PubMed2004

Intrapericardial carcinoid metastasis.

Carcinoid tumors are malignancies of neuroendocrine tissue. Metastasis, most commonly to the liver, is associated with the carcinoid syndrome characterized by secretory symptoms and right-sided valvular heart disease. We report a case of previously unidentified pericardial metastasis, in the absence of any valvular disease, thus, reflecting an unusual cardiac complication of this tumor. A 50-year-old patient with histologically confirmed carcinoid syndrome underwent screening transthoracic echocardiography that demonstrated a large mass posterior to the interatrial septum. The location of this mass was confirmed by transesophageal echocardiography and magnetic resonance imaging to be entirely within the pericardial space without evidence of myocardial involvement. The mass was removed at thoracotomy and histology confirmed metastatic carcinoid disease. Although patients with carcinoid syndrome are at risk of cardiac valvular complications, and should be screened, this case demonstrates an unusual and previously unidentified site of metastatic disease.

Carcinoid Tumor↗
PubMed2003

Cardiac homeobox gene NKX2-5 mutations and congenital heart disease: associations with atrial septal defect and hypoplastic left heart syndrome.

OBJECTIVES: We sought to examine the importance of mutations in the cardiac transcription factor gene NKX2-5 in patients with an atrial septal defect (ASD), patent foramen ovale (PFO), or hypoplastic left heart syndrome (HLHS). BACKGROUND: Mutations in NKX2-5 have been found in families showing secundum ASD and atrioventricular (AV) conduction block and in some individuals with tetralogy of Fallot. The prevalence of NKX2-5 mutations in sporadic cases of ASD/PFO and other forms of congenital heart disease is unknown. METHODS: A cohort of 146 individuals with secundum ASD, PFO complicated by paradoxical embolism, or HLHS were evaluated. Patients with ASD or PFO were ascertained irrespective of family history or associated cardiac abnormalities. The coding region of the NKX2-5 locus was amplified by polymerase chain reaction and sequenced. RESULTS: Among 102 ASD and 25 PFO patients screened, 13 patients (10%) had a positive family history and 5 patients (4%) had AV conduction block. We found one previously documented NKX2-5 missense mutation, T178M, in members of a family with ASD without AV conduction block. One NKX2-5 mutation-positive child from this family had HLHS, although no mutations were subsequently found in 18 patients with sporadic or familial HLHS. In a second ASD family without AV conduction block, we found a missense change, E21Q, previously reported as pathogenic. Because this change did not segregate with disease status, we propose that it is a non-disease-causing polymorphism. CONCLUSIONS: Our findings suggest that NKX2-5 mutations are a relatively infrequent cause of sporadic ASD and HLHS. Screening for NKX2-5 mutations may be warranted in individuals with ASD and a positive family history, irrespective of the presence or absence of AV conduction block.

Adolescent↗
PubMed2002

Prospective study of the effects of antiretroviral therapy on Kaposi sarcoma--associated herpesvirus infection in patients with and without Kaposi sarcoma.

OBJECTIVE: To investigate the effect of highly active antiretroviral therapy (HAART) on circulating Kaposi sarcoma (KS)-associated herpesvirus (KSHV) load in HIV-infected individuals with and without KS. DESIGN: Twenty-nine HIV-infected subjects (21 with KS and 8 without KS) were recruited for the study; they were prospectively studied before and at regular intervals during HAART. METHODS: Patients with KS were clinically assessed using Adult Clinical Trials Group (ACTG) criteria, and sequential blood samples were obtained from all patients for determination of plasma HIV-1 load, CD4 cell count, titer of antibody to KSHV, and KSHV load. RESULTS: Ten of 21 patients with KS had a favorable KS response (complete response, 6; partial response, 4) with HAART alone. Of the 20 subjects with detectable KSHV viremia prior to HAART, over one half (12 [60%]) had an undetectable KSHV load with antiretroviral therapy. There was no significant difference between subjects receiving protease inhibitor- or nonnucleoside reverse transcriptase inhibitor-based treatment combinations. Achieving undetectable KSHV viremia is associated with a better clinical outcome in patients with KS. CONCLUSIONS: To our knowledge, we demonstrate for the first time that both protease inhibitor-based and nonnucleoside reverse transcriptase inhibitor-based antiretroviral treatment combinations may lead to an undetectable KSHV load and confirm that an undetectable KSHV load is associated with KS regression. There was no clear association between CD4 cell count response and KS response to HAART, but there was a significant relationship between HIV load response to HAART and clinical improvement of KS.

Adult↗
PubMed2002

A preliminary evaluation of the differences in the glycosylation of alpha-1-acid glycoprotein between individual liver diseases.

During the acute phase response (APR) to tissue injury or infection, the liver is responsible for the level of mediators such as cytokines required at the site of inflammation and providing the essential components for wound healing and tissue repair. Additionally there are substantial alterations in the expression of plasma proteins of hepatic origin such as alpha-1-acid glycoprotein (AGP). The APR also results in alterations to the branching, sialylation and fucosylation of the oligosaccharide chains of AGP. This study investigated whether liver damage could be correlated with changes in AGP glycosylation in groups of patients with various liver diseases (alcoholic liver disease, hepatitis B, hepatitis C, cirrhosis). Hyperfucosylation occurred in all cases of liver disease, although the hepatitis B and C samples showed a more significant increase in comparison with the others. Additionally N-acetylgalactosamine (GalNAc) was detected in the majority of the hepatitis C samples, which was unexpected since this monosaccharide is not a usual component of the N-linked oligosaccharide chains. It was also determined by concanavalin (con) A chromatography that there is a shift towards the increased branching of the oligosaccharide chains in inflammatory liver diseases compared to normal serum.

Adult↗
PubMed2002

Identification of Kaposi's sarcoma-associated herpesvirus (KSHV)-specific cytotoxic T-lymphocyte epitopes and evaluation of reconstitution of KSHV-specific responses in human immunodeficiency virus type 1-Infected patients receiving highly active antiretroviral therapy.

Following the introduction of highly active antiretroviral therapy (HAART), the incidence of Kaposi's sarcoma (KS) has significantly declined in human immunodeficiency virus type 1 (HIV-1)-positive (HIV-1(+)) individuals and clinical remission is often observed. We hypothesize that these effects are partly due to anti-KS-associated herpesvirus (KSHV) immune restoration. Here, 15-mer overlapping peptides from proteins K12 and K8.1 were used to identify novel KSHV-specific cytotoxic T-lymphocyte epitopes. Three immunogenic peptides, two lytic and one latent, were subsequently used to monitor the anti-KSHV CD8(+) T-cell responses in a cohort of 19 HIV-1(+) KSHV(+/-) KS(+/-) individuals during 52 weeks of HAART. KSHV and HIV-1 loads, KSHV antibody titers, and both CD4(+) and CD8(+) T-lymphocyte counts were enumerated. Prior to HAART, the total number of spot-forming cells (SFC) for all three peptides correlated with both CD4(+) and CD8(+) T-lymphocyte counts (P < or = 0.05) in the KSHV-positive KS-positive cohort (n = 11). Following 52 weeks of HAART, significant decreases in HIV-1 and KSHV loads were associated with significant increases in CD4(+) T-lymphocyte counts and number of SFC for the three KSHV-specific peptides. Although these increases were modest in comparison to the number of SFC observed with the HIV-1 gag peptide SLYNTVATL, they represented a fourfold increase from the baseline, continuing an upward trend to week 52.

AIDS-Related Opportunistic Infections↗