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Biomedical subjects

J P Clewley

Publications and source records attributed to J P Clewley.

At least 19 recordsLinked to original sources
PubMed2002

Virulence typing of Escherichia coli using microarrays.

We describe a microarray based broad-range screening technique for Escherichia coli virulence typing. Gene probes were amplified by PCR from a plasmid bank of characterised E. coli virulence genes and were spotted onto a glass slide to form an array of capture probes. Genomic DNA from E. coli strains which were to be tested for the presence of these virulence gene sequences was labelled with fluorescent cyanine dyes by random amplification and then hybridised against the array of probes. The hybridisation, washing and data analysis conditions were optimised for glass slides, and the applicability of the method for identifying the presence of the virulence genes was determined using reference strains and clinical isolates. It was found to be a sensitive screening method for detecting virulence genes, and a powerful tool for determining the pathotype of E. coli. It will be possible to expand and automate this microarray technique to make it suitable for rapid and reliable diagnostic screening of bacterial isolates.

Carbocyanines↗
PubMed2001

Contribution of influenza and respiratory syncytial virus to community cases of influenza-like illness: an observational study.

BACKGROUND: Respiratory syncytial virus (RSV) is an important cause of lower-respiratory-tract infection in children and elderly people, but its effect in other age-groups is uncertain. We did a community-based observational study of RSV infection in community-dwelling individuals of all ages who presented to general practices in the UK with influenza-like illnesses during three successive winters (1995-96, 1996-97, and 1997-98). METHODS: Nasopharyngeal swabs routinely submitted for virological surveillance were examined by multiplex reverse transcription PCR for influenza A and B viruses and RSV A and B, and findings were related to the clinical incidence of influenza-like illness and acute bronchitis at that time. RSV strains identified were compared with those obtained from hospital admissions. FINDINGS: 480 RSV and 709 influenza viruses were identified from a total of 2226 swabs submitted. Both types of virus were found in all age-groups for between 12 and 20 weeks in each winter. RSV A accounted for 60% of RSV detections. Similar strains of RSV were present in hospital and community patients within the same year, but there were different lineages each year. INTERPRETATION: In individuals diagnosed with influenza-like illness, there is a substantial potential for confusion between illnesses caused by influenza and those caused by RSV. The burden of illness attributable to each needs to be clarified to define optimum management routines.

Adolescent↗
PubMed2001

National surveillance of HIV-1 subtypes for England and Wales: design, methods, and initial findings.

The HIV-1 infections detected in an ongoing national unlinked anonymous HIV surveillance program were subtyped and analyzed according to demographic and risk characteristics. Of the 893 anti--HIV-1--positive specimens allocated to an exposure group, 70% could be subtyped. Almost 25% of infections subtyped were non-B, mostly subtypes A, C, and D. Non-B infections were rare in homosexual and bisexual men and in drug injectors. Forty percent of infections in heterosexual men attending genitourinary medicine clinics were non-B subtypes; of these, 25% were subtype A infections and 59% were subtype C infections. For female clinic attendees, 61% were non-B subtype infections, of which 48% were subtype A infections and 42% were subtype C infections. Of the clinic attendees born in the United Kingdom and Europe, 14% of the men and 35% of the women were infected with non-B subtypes. In contrast, 78% of infections in antenatal patients were non-B subtypes, of which 61% were subtype A and 29% were subtype C. Extrapolation to the estimated 29,700 prevalent adult infections in the United Kingdom indicates that approximately 8,100 (27%) such infections are non-B subtypes and that these are found almost entirely in heterosexuals. The findings suggest spread of infection of non-B subtypes to heterosexuals born in the United Kingdom from individuals infected in regions of high prevalence.

Acute Disease↗
PubMed2001

Recombinant strains of HIV type 1 in the United Kingdom.

Twenty-five recombinant (mosaic) HIV-1 genomes were detected among 151 samples comprising 118 non-B subtype sequences and 33 samples containing subtype B sequences. Seven of the 25 mosaic patterns were similar to characterized circulating recombinant forms (two A/E, four A/G, and one D/F) and one was a MAL-like A/D recombinant. Eighteen of the recombinants had evidence of subtype A sequences in at least one region of their genome. One sample was found to contain a novel recombinant form (pol F, env K). Two samples could not be characterized unambiguously as recombinant forms and a further one appeared to be a complex C/J/D/A genomic form. The majority of the mosaic genomes were recombinants between gag, pol, or env, whereas the C/J/D/A mosaic had cross-over breakpoints within pol. These findings suggest that almost 20% of non-B subtype isolates of HIV-1 circulating in the United Kingdom have mosaic genomes. This shows the diverse origin of HIV-1 strains circulating in the United Kingdom and may have implications for antiretroviral drug resistance.

Cluster Analysis↗
PubMed2001

DNA tags.

Amplification methods could be used to develop tests so that very small protein amounts could be detected. A piece of DNA--a DNA tag--could be coupled to an antibody, and this could then be used to detect a protein antigen by amplification of the DNA tag.

Communicable Diseases↗
PubMed2000

A gag gene heteroduplex mobility assay for subtyping HIV-1.

A heteroduplex mobility assay (HMA) using 753 and 446 base pair (bp) amplicons of the p17/p24 region of the gag gene of HIV-1 has been developed and validated with reference clones and clinical samples representative of subtypes A, B, C, D, E, G, and H. There was complete concordance between the gag HMA assigned subtype and the subtype known from gag or env sequence data or env HMA. The heteroduplexes from both amplicons can be clearly resolved on either MetaPhor XR agarose or MDE polyacrylamide gels. The MetaPhor XR gel system was the more convenient and is the preferred choice for routine HMA subtyping. This gag HMA provides a rapid, simple and inexpensive method for subtyping HIV-1 based on a genomic region other than the commonly used env gene target. The incorporation of gag HMA into subtype determination algorithms should allow the detection of gag/env recombinant strains of HIV-1.

Genes, env↗
PubMed2000

Characterization of a highly divergent TT virus genome.

A novel TT virus (TTV)-like DNA sequence was detected in the serum of a patient (PM) with acute non-A-E hepatitis. The full-length genome sequence, referred to here as PM virus (PMV), was obtained and its relationship to other full or near full-length TTV sequences examined. Although it shares a common genomic arrangement and short conserved regions, the majority of the genome is extremely divergent, displaying an average genetic distance of 0.60 from all other TTV sequences. By comparing PMV with TTV genomes representing the most divergent types so far described, six major groups can be distinguished. The level of genetic diversity seen between these genomes is higher than would be expected within a single virus species. Indeed, PMV could be considered the prototype of an independent taxonomic group within the Circoviridae: family. A genoprevalence study of sera from blood donors and patients with acute hepatitis suggests that PMV is rare.

DNA Virus Infections↗