Biomedical subjects

David Clifford

Publications and source records attributed to David Clifford.

4 recordsLinked to original sources

PubMed2006

Cytotoxic T cell recognition of an HIV-1 reverse transcriptase variant peptide incorporating the K103N drug resistance mutation.

During HIV-1 infection, cytotoxic T cell (CTL) responses exert strong selective pressure on the replicating virus population. Here we report evidence for T cell activity against the drug resistant K103N region of viral reverse transcriptase in three HIV-1 infected patients exposed to NNRTI antiretroviral drugs. We further characterize the response in one patient by ELISPOT analysis. A nine amino acid peptide incorporating 103N was recognized by patient T cells whereas the wild type was not. The RT K103N mutation is selected by the NNRTI class of HIV drugs. We hypothesize that, in certain individuals, CTL responses against 103N-containing epitopes may protect against NNRTI drug resistance. Characterizing such responses in the context of HLA subtypes could lead to tailored HIV drug therapy or to the design of therapeutic vaccines.

Journal Article↗

PubMed2006

Interactive feature finding in liquid chromatography mass spectrometry data.

We propose a method for finding features in liquid chromatography mass spectrometry data that is based on the isotopic pattern of peaks. Our interactive approach to feature finding is carried out across many samples simultaneously and aligns features concurrently. Our scale-independent approach prioritises potential features and is easily adaptable to look for features of a particular mass and charge, paired features in isotopically labeled samples, or differentially expressed features. We demonstrate this by identifying features from normal human adult plasma. We highlight properties of plasma data that illustrate the need to visually check the quality of features found prior to further statistical analysis.

Blood Proteins↗

PubMed2005

Novel biomarkers of human growth hormone action from serum proteomic profiling using protein chip mass spectrometry.

CONTEXT: The detection of exogenous human GH (hGH) administration in athletes poses unique analytical problems, because its short circulating half-life provides only a brief opportunity to detect the administered hormone above endogenous levels. Measurement of novel GH-regulated serum protein biomarkers might provide an indirect method to detect exogenous GH. OBJECTIVE: The objective of this study was to identify new serum biomarkers of GH administration using proteomic profiling. DESIGN: Sera from a previously reported, double-blind, placebo-controlled GH administration trial were analyzed by protein chip mass spectrometry. SETTING: The study was performed at clinical research centers. SUBJECTS: Sixty healthy subjects, aged 18-40 yr, who were not elite athletes, were studied. INTERVENTIONS: Placebo or recombinant hGH treatment (0.1 or 0.2 IU/kg.d; 20 subjects/group) was administered for 4 wk, followed by an 8-wk washout period. MAIN OUTCOME MEASURES: Protein mass profiles were determined on immobilized Cu(2+) chips on d 0 and 21 of GH administration, and multivariate analysis was used to classify subjects into GH and placebo administration groups. RESULTS: When assessed by cross-validation, the classification performance of classifiers based on multivariate analysis of several GH-regulated peaks performed no better than classifiers based on the single best peak. This peak, a prominent biomarker of 15.1 kDa, was purified and identified as hemoglobin alpha-chain. The time course of the GH response of this biomarker is similar to that of other GH-dependent markers, such as IGF-I. CONCLUSION: This study demonstrates that protein mass profiling is an effective tool for the detection of GH administration and suggests that measurement of hemoglobin alpha-chain may have utility as a novel serum biomarker of GH action.

Adolescent↗

PubMed2002

A pilot study of cidofovir for progressive multifocal leukoencephalopathy in AIDS.

OBJECTIVE: To assess the safety, tolerability and effect of cidofovir for HIV-1 associated progressive multifocal leukoencephalopathy. DESIGN: Prospective, open-label study in nine AIDS Clinical Trials Units. PATIENTS AND METHODS: Twenty-four HIV-1-infected individuals, with neuroimaging and clinical findings consistent with PML, and symptoms for 90 days or less, whose diagnosis was confirmed by the detection of JC virus DNA in the cerebrospinal fluid or brain biopsy, received cidofovir 5 mg/kg intravenously at baseline and 1 week, followed by infusions every 2 weeks with the dose adjusted for renal function. Follow-up continued to 24 weeks. The safety of cidofovir and changes in neurological examination scores between baseline and week 8 were assessed. RESULTS: Seventeen subjects were receiving potent antiretroviral agents. Survival at 12 weeks was 54%. The CD4 cell count at entry was significantly associated with survival (P = 0.02). Five subjects discontinued treatment because of toxicity: a 50% or greater decrease in intraocular pressure in either eye in four, and proteinuria in one. Overall, magnetic resonance imaging abnormalities and neurological examination scores worsened. Only two subjects experienced a 25% or greater improvement in neurological examination scores at week 8, which were significantly better in subjects with HIV-1-RNA levels of 500 copies/ml or less at entry compared with those with HIV-1-RNA levels over 500 copies/ml (P = 0.05). CONCLUSION: Cidofovir did not improve neurological examination scores at week 8. However, such scores were significantly better in subjects who entered with suppressed plasma HIV-1-RNA levels, which could be the result of control of HIV-1 infection itself or cidofovir.

Adult↗