148 results on '"Clewley, JP"'
Search Results
2. DNA Amplification: General Concepts and Methods
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Saunders Na and Clewley Jp
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Diagnostic microbiology ,law ,Computer science ,Typing ,Computational biology ,Dna amplification ,Polymerase chain reaction ,law.invention - Abstract
The polymerase chain reaction (PCR) was first described in 1985 (1), although its theoretical roots go back beyond that time (2). It is the most versatile of the amplification methods, the others (see Subheading 4.) are more or less confined to diagnostic applications. For example, the product of a PCR, often referred to as an amplification, can be readily sequenced for diagnostic, typing, fingerprinting, or molecular epidemiologic reasons. PCR is now taking its place in diagnostic microbiology laboratories as an adjunct to culture and serologic tests PCR tests are available in kit form under the AMPLICOR™ name (RocheDiagnostic Systems, Base & Switzerland).
- Published
- 2003
3. RNA interference pays off.
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Clewley, JP
- Abstract
Reports that small RNA molecules have been shown to modulate gene expression and to inhibit the replication of viruses. Classes of small RNA molecules; Type of RNA interference induced by the small double-stranded RNA molecules; Popularity of RNA interference in the field of genetics research.
- Published
- 2003
4. Prevalence of disease related prion protein in anonymous tonsil specimens in Britain: cross sectional opportunistic survey.
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Clewley JP, Kelly CM, Andrews N, Vogliqi K, Mallinson G, Kaisar M, Hilton DA, Ironside JW, Edwards P, McCardle LM, Ritchie DL, Dabaghian R, Ambrose HE, and Gill ON
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- 2009
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5. Diagnostic strategy used to establish etiologies of encephalitis in a prospective cohort of patients in England.
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Ambrose HE, Granerod J, Clewley JP, Davies NW, Keir G, Cunningham R, Zuckerman M, Mutton KJ, Ward KN, Ijaz S, Crowcroft NS, and Brown DW
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- Adolescent, Adult, Antibodies cerebrospinal fluid, Bacterial Infections diagnosis, Bacterial Infections microbiology, Cerebrospinal Fluid immunology, Child, Child, Preschool, Cohort Studies, Diagnosis, Differential, England, Female, Humans, Immune System Diseases diagnosis, Male, Middle Aged, Prospective Studies, Virus Diseases diagnosis, Virus Diseases virology, Young Adult, Algorithms, Clinical Laboratory Techniques methods, Encephalitis diagnosis, Encephalitis etiology
- Abstract
The laboratory diagnostic strategy used to determine the etiology of encephalitis in 203 patients is reported. An etiological diagnosis was made by first-line laboratory testing for 111 (55%) patients. Subsequent testing, based on individual case reviews, resulted in 17 (8%) further diagnoses, of which 12 (71%) were immune-mediated and 5 (29%) were due to infection. Seventy-five cases were of unknown etiology. Sixteen (8%) of 203 samples were found to be associated with either N-methyl-d-aspartate receptor or voltage-gated potassium channel complex antibodies. The most common viral causes identified were herpes simplex virus (HSV) (19%) and varicella-zoster virus (5%), while the most important bacterial cause was Mycobacterium tuberculosis (5%). The diagnostic value of testing cerebrospinal fluid (CSF) for antibody was assessed using 139 samples from 99 patients, and antibody was detected in 46 samples from 37 patients. Samples collected at 14 to 28 days were more likely to be positive than samples taken 0 to 6 days postadmission. Three PCR-negative HSV cases were diagnosed by the presence of virus-specific antibody in the central nervous system (CNS). It was not possible to make an etiological diagnosis for one-third of the cases; these were therefore considered to be due to unknown causes. Delayed sampling did not contribute to these cases. Twenty percent of the patients with infections with an unknown etiology showed evidence of localized immune activation within the CNS, but no novel viral DNA or RNA sequences were found. We conclude that a good standard of clinical investigation and thorough first-line laboratory testing allows the diagnosis of most cases of infectious encephalitis; testing for CSF antibodies allows further cases to be diagnosed. It is important that testing for immune-mediated causes also be included in a diagnostic algorithm.
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- 2011
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6. Causes of encephalitis and differences in their clinical presentations in England: a multicentre, population-based prospective study.
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Granerod J, Ambrose HE, Davies NW, Clewley JP, Walsh AL, Morgan D, Cunningham R, Zuckerman M, Mutton KJ, Solomon T, Ward KN, Lunn MP, Irani SR, Vincent A, Brown DW, and Crowcroft NS
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- Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, Communicable Diseases immunology, Communicable Diseases microbiology, Encephalitis immunology, Encephalitis microbiology, England epidemiology, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, Multivariate Analysis, Prospective Studies, Regression Analysis, Young Adult, Communicable Diseases epidemiology, Communicable Diseases etiology, Encephalitis epidemiology, Encephalitis etiology
- Abstract
Background: Encephalitis has many causes, but for most patients the cause is unknown. We aimed to establish the cause and identify the clinical differences between causes in patients with encephalitis in England., Methods: Patients of all ages and with symptoms suggestive of encephalitis were actively recruited for 2 years (staged start between October, 2005, and November, 2006) from 24 hospitals by clinical staff. Systematic laboratory testing included PCR and antibody assays for all commonly recognised causes of infectious encephalitis, investigation for less commonly recognised causes in immunocompromised patients, and testing for travel-related causes if indicated. We also tested for non-infectious causes for acute encephalitis including autoimmunity. A multidisciplinary expert team reviewed clinical presentation and hospital tests and directed further investigations. Patients were followed up for 6 months after discharge from hospital., Findings: We identified 203 patients with encephalitis. Median age was 30 years (range 0-87). 86 patients (42%, 95% CI 35-49) had infectious causes, including 38 (19%, 14-25) herpes simplex virus, ten (5%, 2-9) varicella zoster virus, and ten (5%, 2-9) Mycobacterium tuberculosis; 75 (37%, 30-44) had unknown causes. 42 patients (21%, 15-27) had acute immune-mediated encephalitis. 24 patients (12%, 8-17) died, with higher case fatality for infections from M tuberculosis (three patients; 30%, 7-65) and varicella zoster virus (two patients; 20%, 2-56). The 16 patients with antibody-associated encephalitis had the worst outcome of all groups-nine (56%, 30-80) either died or had severe disabilities. Patients who died were more likely to be immunocompromised than were those who survived (OR = 3·44)., Interpretation: Early diagnosis of encephalitis is crucial to ensure that the right treatment is given on time. Extensive testing substantially reduced the proportion with unknown cause, but the proportion of cases with unknown cause was higher than that for any specific identified cause., Funding: The Policy Research Programme, Department of Health, UK., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
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- 2010
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7. Large-scale immunohistochemical examination for lymphoreticular prion protein in tonsil specimens collected in Britain.
- Author
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de Marco MF, Linehan J, Gill ON, Clewley JP, and Brandner S
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- Carrier State epidemiology, Carrier State metabolism, Cohort Studies, Creutzfeldt-Jakob Syndrome metabolism, England epidemiology, Humans, Immunoenzyme Techniques, Prevalence, Scotland epidemiology, Creutzfeldt-Jakob Syndrome epidemiology, Palatine Tonsil metabolism, Prions metabolism
- Abstract
There have been 173 cases of variant Creutzfeldt-Jakob disease (vCJD) in the UK, as of 5 July 2010, as a result of the bovine spongiform encephalopathy epidemic. The number of individuals subclinically infected with vCJD, and thus the eventual number of cases, remains, however, uncertain. In an attempt to address this problem, 63,007 tonsil tissue specimens were previously tested by enzyme immunoassay (EIA) for the presence of disease-related prion protein (PrP(res)) and found to be negative. To confirm the reliability of this result, all those in the birth cohort most at risk (1961-1985) and a few others, including controls, have now been tested by immunohistochemistry (IHC). Histological slides were prepared from 10,075 anonymized formalin-fixed, paraffin-embedded tissues and examined for PrP(res) with two anti-prion protein antibodies, ICMS35 and KG9. One specimen showed a single strongly positive follicle with both antibodies, on two slides from adjacent sections. As this specimen was negative when it was further investigated by EIA, IHC, and immunoblotting, it is unclear whether the patient from whom the tonsil came will go on to develop vCJD. If, however, this is the case, then a finding of 1 out of 9160 gives a prevalence of disease-related prion protein in the British population of 109 per million, with a 95% confidence interval (CI) of 3-608 per million, which is not statistically different (exact p = 0.63) from population prevalence estimates based on finding three positives out of 10 278 in a previous IHC study of appendix tissue. If this is not the case, a finding of 0 out of 9160 gives a prevalence of 0-403 per million (95% CI) for the 1961-1985 cohort, which is also not different (exact p = 0.25) from previous population prevalence estimates. Therefore, the results of this work could be summarized as finding, by IHC, no or one vCJD-positive individual., (Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)
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- 2010
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8. Causality in acute encephalitis: defining aetiologies.
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Granerod J, Cunningham R, Zuckerman M, Mutton K, Davies NW, Walsh AL, Ward KN, Hilton DA, Ambrose HE, Clewley JP, Morgan D, Lunn MP, Solomon T, Brown DW, and Crowcroft NS
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- Acute Disease, Amebiasis complications, Amebiasis diagnosis, Bacterial Infections complications, Bacterial Infections diagnosis, Encephalitis diagnosis, Encephalitis microbiology, Humans, Rickettsia Infections complications, Rickettsia Infections diagnosis, Toxoplasmosis complications, Toxoplasmosis diagnosis, United Kingdom epidemiology, Virus Diseases complications, Virus Diseases diagnosis, Encephalitis etiology
- Abstract
Defining the causal relationship between a microbe and encephalitis is complex. Over 100 different infectious agents may cause encephalitis, often as one of the rarer manifestations of infection. The gold-standard techniques to detect causative infectious agents in encephalitis in life depend on the study of brain biopsy material; however, in most cases this is not possible. We present the UK perspective on aetiological case definitions for acute encephalitis and extend them to include immune-mediated causes. Expert opinion was primarily used and was supplemented by literature-based methods. Wide usage of these definitions will facilitate comparison between studies and result in a better understanding of the causes of this devastating condition. They provide a framework for regular review and updating as the knowledge base increases both clinically and through improvements in diagnostic methods. The importance of new and emerging pathogens as causes of encephalitis can be assessed against the principles laid out here.
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- 2010
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9. Phylogenetic reconstruction of transmission events from individuals with acute HIV infection: toward more-rigorous epidemiological definitions.
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Brown AE, Gifford RJ, Clewley JP, Kucherer C, Masquelier B, Porter K, Balotta C, Back NK, Jorgensen LB, de Mendoza C, Bhaskaran K, Gill ON, Johnson AM, and Pillay D
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- Acute Disease, Female, Genes, pol genetics, Genetic Variation, HIV Infections virology, HIV-1 classification, Humans, Male, HIV Infections epidemiology, HIV Infections transmission, HIV-1 genetics, Phylogeny
- Abstract
Phylogenetic reconstructions of transmission events from individuals with acute human immunodeficiency virus (HIV) infection are conducted to illustrate this group's heightened infectivity. Varied definitions of acute infection and assumptions about observed phylogenetic clusters may produce misleading results. We conducted a phylogenetic analysis of HIV pol sequences from 165 European patients with estimated infection dates and calculated the difference between dates within clusters. Nine phylogenetic clusters were observed. Comparison of dates within clusters revealed that only 2 could have been generated during acute infection. Previous analyses may have incorrectly assigned transmission events to the acutely HIV infected when they were more likely to have occurred during chronic infection.
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- 2009
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10. Implications for HIV testing policy derived from combining data on voluntary confidential testing with viral sequences and serological analyses.
- Author
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Brown AE, Murphy G, Rinck G, Clewley JP, Hill C, Parry JV, Johnson AM, Pillay D, and Gill ON
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- Algorithms, Base Sequence, Confidentiality, Genotype, HIV Infections genetics, HIV Seropositivity, Health Policy, Humans, Male, Phylogeny, Serologic Tests, HIV Infections prevention & control, HIV-1 genetics, Homosexuality, Male, Patient Acceptance of Health Care
- Abstract
Objectives: Laboratory, clinical and sequence-based data were combined to assess the differential uptake of voluntary confidential HIV testing (VCT) according to risk and explore the occurrence of HIV transmission from individuals with recently acquired HIV infection, before the diagnostic opportunity., Methods: Between 1999 and 2002, nearly 30,000 anonymous tests for previously undiagnosed HIV infection were conducted among men who have sex with men (MSM) attending 15 sentinel sexually transmitted infection (STI) clinics in England, Wales and Northern Ireland. Using a serological testing algorithm, undiagnosed HIV-infected men were categorised into those with recent and non-recent infection. VCT uptake was compared between HIV-negative, recently HIV-infected and non-recently HIV-infected men. A phylogenetic analysis of HIV pol sequences from 127 recently HIV-infected MSM was conducted to identify instances in which transmission may have occurred before the diagnostic opportunity., Results: HIV-negative MSM were more likely to receive VCT at clinic visits compared with undiagnosed HIV-infected MSM (56% (14,020/24,938) vs 31% (335/1072); p<0.001). Recently HIV-infected MSM were more likely to receive VCT compared with those with non-recent infections (42% (97/229) vs 28% (238/844); p<0.001). 22% (95/425) of undiagnosed HIV-infected MSM with STI received VCT. Phylogenetic analysis revealed at least seven transmissions may have been generated by recently HIV-infected MSM: a group that attended STI clinics soon after seroconversion., Conclusions: The integration of clinical, laboratory and sequence-based data reveals the need for specific targeting of the recently HIV exposed, and those with STI, for VCT. VCT promotion alone may be limited in its ability to prevent HIV transmission.
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- 2009
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11. Virus discovery by sequence-independent genome amplification.
- Author
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Ambrose HE and Clewley JP
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- Humans, Viruses isolation & purification, Genome, Viral, Nucleic Acid Amplification Techniques methods, Virus Diseases virology, Viruses genetics
- Abstract
Genome sequences from several blood borne and respiratory viruses have recently been recovered directly from clinical specimens by variants of a technique known as sequence-independent single primer amplification. This and related methods are increasingly being used to search for the causes of diseases of presumed infectious aetiology, but for which no agent has yet been found. Other methods that do not require prior knowledge of the genome sequence of any virus that may be present in the patient specimen include whole genome amplification, random PCR and subtractive hybridisation and differential display. This review considers the development and application of these techniques.
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- 2006
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12. Genetic variants of parvovirus B19 identified in the United Kingdom: implications for diagnostic testing.
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Cohen BJ, Gandhi J, and Clewley JP
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- Adult, DNA Primers, False Negative Reactions, Female, Genetic Variation, Humans, Male, Middle Aged, Parvoviridae Infections virology, Parvovirus B19, Human isolation & purification, Polymerase Chain Reaction, Reagent Kits, Diagnostic standards, Species Specificity, United Kingdom, Viral Nonstructural Proteins genetics, Parvoviridae Infections diagnosis, Parvovirus B19, Human genetics
- Abstract
Background: Discrepant results in diagnostic parvovirus B19 PCR assays have been observed with strains showing nucleotide sequence variation., Objectives and Study Design: To perform phylogenetic analysis on two parvovirus B19 strains that gave discrepant PCR results., Results: One strain was found to be genotype 2; the second strain was genotype 3., Conclusions: Parvovirus B19 genotypes 2 and 3 strains were identified in diagnostic samples of UK origin following the investigation of discrepant PCR results. More structured investigations are needed to estimate the prevalence of these variants. In the meantime, diagnostic PCR results should be interpreted cautiously when they are at variance with serological testing. Manufacturers of PCR kits for the detection of B19 sequences will need to consider re-designing their primers.
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- 2006
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13. An immunoassay for the pathological form of the prion protein based on denaturation and time resolved fluorometry.
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Dabaghian RH, Barnard G, McConnell I, and Clewley JP
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- Brain pathology, Brain Chemistry, Fluorometry methods, Guanidine, Humans, Palatine Tonsil chemistry, Palatine Tonsil pathology, PrPSc Proteins immunology, Prions chemistry, Prions immunology, Protein Denaturation, Sensitivity and Specificity, Solubility, Spleen chemistry, Spleen pathology, Creutzfeldt-Jakob Syndrome diagnosis, Fluorescent Antibody Technique, PrPSc Proteins analysis, Prion Diseases diagnosis, Prions analysis
- Abstract
Concern about the possible secondary spread of variant Creutzfeldt-Jakob disease (vCJD) through blood transfusion and blood products has increased the need for a sensitive and rapid test for the identification of PrP(Sc) in specimens collected non-invasively from living persons. Furthermore, an accurate estimate of the prevalence of pre-clinical vCJD in the British population would be possible if there were such a test that could be applied to specimens available readily (e.g. blood and urine). As a first step towards that goal, we have developed a simple and sensitive test for the detection of PrP(Sc) in peripheral tissues and brain of vCJD patients, based on the differential extraction of PrP(Sc) with guanidine hydrochloride. The prion protein (PrP) isoforms are extracted sequentially from homogenized tissue by applying two different concentrations of this chaotropic agent. Each extraction yields a fraction of the PrP isoforms with different solubilities in guanidine hydrochloride. Quantitation of the two fractions (relatively insoluble or relatively soluble) using time resolved fluorescence (DELFIA) as a reporter system allows differentiation between PrP(Sc) infected and non-infected tissues. The assay has a detection limit of 10 pg PrP, is robust and could be automated.
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- 2006
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14. Emergence of a three codon deletion in gag p17 in HIV type 1 subtype C long-term survivors, and general population spread.
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McCormack GP, Glynn JR, Clewley JP, Crampin AC, Travers SA, Redmond N, Keane TM, Sibande F, Mulawa D, and Fine PE
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- Amino Acid Sequence, Gene Products, gag chemistry, HIV Antigens chemistry, Molecular Sequence Data, Polymerase Chain Reaction, Viral Proteins chemistry, gag Gene Products, Human Immunodeficiency Virus, Codon, Gene Products, gag genetics, HIV Antigens genetics, HIV Long-Term Survivors, Sequence Deletion, Viral Proteins genetics
- Abstract
In a population-based study in northern Malawi we investigated HIV-1 subtype C gag and env gene sequences associated with long-term survival. DNA samples were available from 31 individuals surviving between population surveys carried out in the 1980s and 1990s. Most survivors with paired sequences dating from the 1980s and the 1990s had a three codon deletion in the gag p17 region of the sequence retrieved from the sample collected in the 1990s that was not present in the sequence from the same individual dating from the 1980s. This deletion was also not present in any other 1980s sequences from Malawi, but was common in samples collected in Malawi in the 1990s. The deletion is equivalent to the loss of three amino acids in the D helix region of the gag protein, and may be associated with longer survival and onward transmission.
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- 2006
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15. Genetic analysis reveals the complex structure of HIV-1 transmission within defined risk groups.
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Hué S, Pillay D, Clewley JP, and Pybus OG
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- Disease Outbreaks, Evolution, Molecular, Genes, pol, HIV Infections epidemiology, HIV-1 classification, HIV-1 isolation & purification, Humans, Male, Molecular Sequence Data, Phylogeny, Risk Factors, Time Factors, United Kingdom epidemiology, HIV Infections transmission, HIV Infections virology, HIV-1 genetics
- Abstract
We explored the epidemic history of HIV-1 subtype B in the United Kingdom by using statistical methods that infer the population history of pathogens from sampled gene sequence data. Phylogenetic analysis of HIV-1 pol gene sequences from Britain showed at least six large transmission chains, indicating a genetically variable, but epidemiologically homogeneous, epidemic among men having sex with men. Through coalescent-based analysis, we showed that these chains arose through separate introductions of subtype B strains into the United Kingdom in the early to mid-1980s. After an initial period of exponential growth, the rate of spread generally slowed in the early 1990s, which is more likely to correlate with behavior change than with reduced infectiousness resulting from highly active antiretroviral therapy. Our results provide insights into the complexity of HIV-1 epidemics that must be considered when developing HIV monitoring and prevention initiatives.
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- 2005
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16. Investigation of HIV-1 transmission events by phylogenetic methods: requirement for scientific rigour.
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Hué S, Clewley JP, Cane PA, and Pillay D
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- Genes, Viral, Humans, Phylogeny, Contact Tracing methods, HIV Infections transmission, HIV-1 genetics
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- 2005
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17. Biotechnology and microbiology--have reached the end of the line?
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Clewley JP
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- Humans, Serologic Tests instrumentation, Serologic Tests methods, Serologic Tests trends
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- 2004
18. Prospects for the development of pre-mortem laboratory diagnostic tests for Creutzfeldt-Jakob disease.
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Dabaghian RH, Mortimer PP, and Clewley JP
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- Animals, Cattle, Encephalopathy, Bovine Spongiform diagnosis, Humans, Models, Molecular, PrPC Proteins chemistry, PrPSc Proteins blood, Creutzfeldt-Jakob Syndrome diagnosis, PrPSc Proteins analysis
- Abstract
At present the diagnosis of Creutzfeldt-Jakob disease (CJD) and related transmissible spongiform encephalopathies in humans is based on clinical criteria and (at post-mortem) the histopathological and immunological examination of brain tissue. The misfolded prion protein, PrPSc, is the single most significant marker, but its recognition by standard serological methods is complicated by its antigenic similarity to the normal prion protein, PrPC. Although there are commercial diagnostic assays available for bovine spongiform encephalopathy using brain specimens taken at slaughter, there are no suitable pre-mortem assays for cattle and none either for pre-mortem human disease. Especially in view of the recent report of variant CJD transmission by blood transfusion, it is important that tests for pre-symptomatic infections are developed. This will safeguard the blood supply and, for example, prevent the transmission of CJD in neurosurgery. This paper reviews the current and prospective approaches to the pre-mortem diagnosis of CJD, in particular its variant form., (2004 John Wiley & Sons, Ltd.)
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- 2004
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19. Timing and reconstruction of the most recent common ancestor of the subtype C clade of human immunodeficiency virus type 1.
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Travers SA, Clewley JP, Glynn JR, Fine PE, Crampin AC, Sibande F, Mulawa D, McInerney JO, and McCormack GP
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- Gene Products, gag genetics, Genes, env, Genes, gag, Genotype, HIV Antigens genetics, HIV Core Protein p24 genetics, HIV Envelope Protein gp120 genetics, HIV Infections epidemiology, HIV-1 isolation & purification, Humans, Malawi epidemiology, Molecular Epidemiology, Phylogeny, Regression Analysis, Time Factors, Viral Proteins genetics, gag Gene Products, Human Immunodeficiency Virus, Evolution, Molecular, HIV Infections virology, HIV-1 classification, HIV-1 genetics
- Abstract
Human immunodeficiency virus type 1 (HIV-1) subtype C is responsible for more than 55% of HIV-1 infections worldwide. When this subtype first emerged is unknown. We have analyzed all available gag (p17 and p24) and env (C2-V3) subtype C sequences with known sampling dates, which ranged from 1983 to 2000. The majority of these sequences come from the Karonga District in Malawi and include some of the earliest known subtype C sequences. Linear regression analyses of sequence divergence estimates (with four different approaches) were plotted against sample year to estimate the year in which there was zero divergence from the reconstructed ancestral sequence. Here we suggest that the most recent common ancestor of subtype C appeared in the mid- to late 1960s. Sensitivity analyses, by which possible biases due to oversampling from one district were explored, gave very similar estimates.
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- 2004
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20. Shotgun sequencing the microbial diversity of the Earth.
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Clewley JP
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- Animals, Genetics, Microbial classification, Humans, Environmental Microbiology, Genetic Variation, Genetics, Microbial trends, Public Health
- Published
- 2004
21. Surveillance of HIV-1 subtypes among heterosexuals in England and Wales, 1997-2000.
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Tatt ID, Barlow KL, Clewley JP, Gill ON, and Parry JV
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- Africa ethnology, Algorithms, Asia ethnology, England epidemiology, Europe ethnology, Female, Genes, env, Genes, gag, Genes, pol, Genetic Variation, HIV Infections epidemiology, HIV-1 genetics, HIV-1 isolation & purification, Heterosexuality, Humans, Male, Population Surveillance, Recombination, Genetic, Risk Factors, Wales epidemiology, HIV Infections classification, HIV Infections virology, HIV-1 classification
- Abstract
The molecular diversity and demographic characteristics among 976 anti-HIV-1-positive heterosexuals attending 15 sexually transmitted infection (STI) clinics participating in an unlinked anonymous HIV prevalence serosurvey in England and Wales during 1997-2000 were investigated. Subtypes were assigned by heteroduplex mobility assay or sequencing of the p17/p24 region of gag and the V3/V4 region of env and by sequencing of the protease gene. Overall, there was no significant change in the subtype distribution, with subtype C accounting for the majority (32%) of subtyped infections. Subtypes B (29%), A (12%), circulating recombinant forms (CRFs, 9%), unique recombinant forms (URFs, 8%), and subtypes D-H (8%) were also detected. Thirty-nine percent of infections in men were with subtype B, whereas subtype C was most common (38%) in women. Logistic regression analyses showed the relative risk (RR) of infection with a non-B subtype, compared with subtype B, to be greater in African-born individuals (RR = 28.9, P < 0.01), among newly diagnosed infections (RR = 3.4, P < 0.01), and in women (RR = 2.4, P < 0.01). These findings indicate a high level of genetic diversity among HIV-infected heterosexual STI clinic attendees in England and Wales. Recently, subtype C has become most prevalent, particularly in younger age groups, suggesting recent acquisition of this viral strain. The high proportion of non-B, CRF, and URF infections among UK-born individuals is consistent with mixing between migrants and UK-born individuals in England and Wales. As migration patterns change, continued monitoring of HIV genetic diversity will aid understanding of transmission patterns.
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- 2004
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22. New simian immunodeficiency virus infecting De Brazza's monkeys (Cercopithecus neglectus): evidence for a cercopithecus monkey virus clade.
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Bibollet-Ruche F, Bailes E, Gao F, Pourrut X, Barlow KL, Clewley JP, Mwenda JM, Langat DK, Chege GK, McClure HM, Mpoudi-Ngole E, Delaporte E, Peeters M, Shaw GM, Sharp PM, and Hahn BH
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- Amino Acid Sequence, Animals, Base Sequence, Genome, Viral, Molecular Sequence Data, Phylogeny, Sequence Analysis, DNA, Simian Immunodeficiency Virus genetics, Simian Immunodeficiency Virus isolation & purification, Cercopithecus virology, Monkey Diseases virology, Simian Acquired Immunodeficiency Syndrome virology, Simian Immunodeficiency Virus classification
- Abstract
Nearly complete sequences of simian immunodeficiency viruses (SIVs) infecting 18 different nonhuman primate species in sub-Saharan Africa have now been reported; yet, our understanding of the origins, evolutionary history, and geographic distribution of these viruses still remains fragmentary. Here, we report the molecular characterization of a lentivirus (SIVdeb) naturally infecting De Brazza's monkeys (Cercopithecus neglectus). Complete SIVdeb genomes (9,158 and 9227 bp in length) were amplified from uncultured blood mononuclear cell DNA of two wild-caught De Brazza's monkeys from Cameroon. In addition, partial pol sequences (650 bp) were amplified from four offspring of De Brazza's monkeys originally caught in the wild in Uganda. Full-length (9068 bp) and partial pol (650 bp) SIVsyk sequences were also amplified from Sykes's monkeys (Cercopithecus albogularis) from Kenya. Analysis of these sequences identified a new SIV clade (SIVdeb), which differed from previously characterized SIVs at 40 to 50% of sites in Pol protein sequences. The viruses most closely related to SIVdeb were SIVsyk and members of the SIVgsn/SIVmus/SIVmon group of viruses infecting greater spot-nosed monkeys (Cercopithecus nictitans), mustached monkeys (Cercopithecus cephus), and mona monkeys (Cercopithecus mona), respectively. In phylogenetic trees of concatenated protein sequences, SIVdeb, SIVsyk, and SIVgsn/SIVmus/SIVmon clustered together, and this relationship was highly significant in all major coding regions. Members of this virus group also shared the same number of cysteine residues in their extracellular envelope glycoprotein and a high-affinity AIP1 binding site (YPD/SL) in their p6 Gag protein, as well as a unique transactivation response element in their viral long terminal repeat; however, SIVdeb and SIVsyk, unlike SIVgsn, SIVmon, and SIVmus, did not encode a vpu gene. These data indicate that De Brazza's monkeys are naturally infected with SIVdeb, that this infection is prevalent in different areas of the species' habitat, and that geographically diverse SIVdeb strains cluster in a single virus group. The consistent clustering of SIVdeb with SIVsyk and the SIVmon/SIVmus/SIVgsn group also suggests that these viruses have evolved from a common ancestor that likely infected a Cercopithecus host in the distant past. The vpu gene appears to have been acquired by a subset of these Cercopithecus viruses after the divergence of SIVdeb and SIVsyk.
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- 2004
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23. The behaviour of microbes.
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Clewley JP
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- Adaptation, Physiological, Animals, Bacteria pathogenicity, Host-Parasite Interactions physiology, Humans, Molecular Biology, Symbiosis genetics, Symbiosis physiology, Viruses pathogenicity, Bacteria genetics, Genetics, Microbial, Host-Parasite Interactions genetics, Social Behavior, Viruses genetics
- Abstract
Viruses and bacteria have complex interactions with their hosts, beyond mere replication in them. They range from those that are detrimental, to others that may be non-pathogenic or even beneficial. Molecular techniques can help to unravel these interactions, sometimes revealing phenomena that benefit host as well as microbial populations.
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- 2004
24. Enigmas and paradoxes: the genetic diversity and prevalence of the primate lentiviruses.
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Clewley JP
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- Animals, Biological Evolution, Gene Order, Genes, Viral, Genome, Viral, HIV-1 genetics, HIV-2 genetics, Humans, Lentivirus Infections transmission, Lentiviruses, Primate classification, Sequence Homology, Viral Proteins genetics, Genetic Variation, Lentivirus Infections virology, Lentiviruses, Primate genetics, Phylogeny
- Abstract
In a comparatively few years a previously unknown virus has spread from its animal host to infect more than 40 million people by the end of 2003, causing an estimated 3 million deaths in that year (World Health Organization figures). The size of this human immunodeficiency virus (HIV) epidemic and its associated health, social and economic problems make it imperative that we understand how its two types, HIV-1 and HIV-2, have evolved from their simian relatives, the primate lentiviruses (PLVs). There are several features of the PLVs that may be considered enigmatic or even paradoxical, and which are relevant to studies of their evolution. These reflect the difference in the natural history of PLV-infected apes and humans compared with PLV-infected monkey species, and the apparent host-dependent evolution of some PLV sequences in spite of the relative ease of transmission between primate species.
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- 2004
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25. HIV-1 pol gene variation is sufficient for reconstruction of transmissions in the era of antiretroviral therapy.
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Hué S, Clewley JP, Cane PA, and Pillay D
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- Anti-HIV Agents therapeutic use, Databases, Genetic, Drug Resistance, Viral genetics, Genes, env, Genes, gag, HIV Infections drug therapy, HIV Infections virology, HIV-1 classification, Humans, Phylogeny, Polymerase Chain Reaction methods, Sequence Alignment, Genes, pol, Genetic Variation, HIV Infections transmission, HIV-1 genetics
- Abstract
Objectives: We wished to assess the potential of using HIV-1 pol gene for the identification of transmissions events by phylogenetic means in the era of antiretroviral drug selective pressure., Design: The relatedness of the viruses within a large database of pol sequences generated from HIV-1 infected individuals from the UK was reconstructed by phylogenetic analyses., Methods: A total of 140 pol sequences were selected out of the 2500 database entries, on the basis of a pairwise genetic distance higher than 95%. Neighbour Joining and Maximum Likelihood trees were implemented. Trees were reconstructed after exclusion of codon positions associated with drug resistance from the original pol alignment. Trees based on the corresponding env and gag genes were implemented to confirm the linkages., Results: Up to 23 transmission clusters were identified, supported by high bootstrap values (> 99), congruent epidemiological data and/or similar drug resistance motifs. The topology of the tree was consistent after exclusion of the drug resistance associated codons. Identical topologies were obtained in trees implemented from gag and env genes alignments., Conclusions: Despite its genetic conservation, the HIV-1 pol gene holds sufficient variability to permit the phylogenetic reconstruction of transmissions. Identical clusters were obtained whichever of the three principal genes is considered and no bias was induced by the presence of drug resistance mutations. These findings demonstrate the important epidemiological information inherent within routinely collected laboratory data, which can assist in estimating rates of recent HIV-1 transmission within a population.
- Published
- 2004
- Full Text
- View/download PDF
26. Phylodynamics: a conjunction of epidemiology and evolution?
- Author
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Clewley JP
- Subjects
- Humans, Epidemiologic Studies, Phylogeny, Population Surveillance
- Published
- 2004
27. A role for arrays in clinical virology: fact or fiction?
- Author
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Clewley JP
- Subjects
- DNA, Viral analysis, Humans, Virology methods, Virus Diseases virology, Oligonucleotide Array Sequence Analysis methods, Research, Virus Diseases diagnosis, Virus Diseases epidemiology, Viruses classification, Viruses genetics, Viruses isolation & purification
- Abstract
Microarrays of DNA probes have at least three roles in clinical virology. These are: firstly, in diagnosis, to recognise the causative agent of an illness; secondly, for molecular typing for (i) patient management, (ii) epidemiological reasons (e.g. investigating routes of transmission), (iii) purposes related to vaccine use; and thirdly, in research, to investigate the interactions between the virus and the host cell. Microarrays intended for syndromic diagnostic purposes require genome specific probes to capture the unknown target viral sequences and thereby reveal the presence of that virus in a test sample. Microarrays intended for typing and patient management, e.g. monitoring antiviral drug resistant mutations require a set of probes representing the important sequence variants of one or more viral genes. Microarrays intended for research into virus-host interactions require probes representative of each individual gene or mRNA of either the virus or the host genome. Diagnostic microarrays are dependent for their utility and versatility on generic, multiplex or random polymerase chain reactions that will amplify any of several (unknown) viral target sequences from a patient sample. In this review, the existing and potential applications of microarrays in virology, and the problems that need to be overcome for future success, are discussed.
- Published
- 2004
- Full Text
- View/download PDF
28. The continuing quest for a pre-mortem test for TSEs.
- Author
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Clewley JP
- Subjects
- Animals, Antibodies, Enzyme-Linked Immunosorbent Assay, Humans, Polymerase Chain Reaction, PrPC Proteins immunology, PrPSc Proteins immunology, Prion Diseases transmission, Sensitivity and Specificity, United Kingdom, Biomarkers, Diagnostic Tests, Routine, PrPC Proteins analysis, PrPSc Proteins analysis, Prion Diseases diagnosis
- Published
- 2003
29. The day of the phage.
- Author
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Clewley JP
- Subjects
- Bacteriological Techniques methods, Bacteriophages genetics, Genome, Bacterial, Humans, Bacteriological Techniques trends, Bacteriophages physiology
- Published
- 2003
30. Coxsackievirus B3 sequences in the blood of a neonate with congenital myocarditis, plus serological evidence of maternal infection.
- Author
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Bendig JW, Franklin OM, Hebden AK, Backhouse PJ, Clewley JP, Goldman AP, and Piggott N
- Subjects
- Coxsackievirus Infections virology, Enterovirus B, Human classification, Enterovirus B, Human immunology, Fatal Outcome, Female, Humans, Immunoglobulin M blood, Infant, Newborn, Pregnancy, Pregnancy Complications, Infectious virology, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Coxsackievirus Infections transmission, Enterovirus B, Human genetics, Enterovirus B, Human isolation & purification, Infectious Disease Transmission, Vertical, Myocarditis virology, RNA, Viral blood
- Abstract
A fatal case of myocarditis in a neonate is described. The clinical features were evident at birth, and enteroviral RNA was detected in the blood of the baby on the day of birth and again 10 days later by a generic enterovirus nested reverse transcription-polymerase chain reaction (RT-PCR) assay. The enterovirus RNA was subsequently retested by a separate, newly developed nested RT-PCR assay yielding a PCR product within the VP1 coding region suitable for sequencing. Identical 239-base pair sequences were obtained from the RNA of the two blood samples and this sequence most closely resembled coxsackievirus B3 (94% identity). The baby's mother was pyrexial immediately postpartum and an early antenatal serum and a serum sample collected 10 days postpartum tested in parallel for enterovirus IgM antibody showed negative to strong-positive seroconversion. Infection of the mother was the likely primary event with in utero transfer of the virus to the fetus in the last few days of pregnancy. Neonatal blood is a valuable specimen for enterovirus diagnosis by RT-PCR. A newly developed nested RT-PCR assay was successful in typing the enterovirus from stored RNA extracted directly from the blood samples. Serology for enterovirus IgM antibody can be useful for convalescent diagnosis of enterovirus infection in the mother, especially with earlier serum for comparison., (Copyright 2003 Wiley-Liss, Inc.)
- Published
- 2003
- Full Text
- View/download PDF
31. Characterization of a novel simian immunodeficiency virus (SIVmonNG1) genome sequence from a mona monkey (Cercopithecus mona).
- Author
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Barlow KL, Ajao AO, and Clewley JP
- Subjects
- Animals, Cercopithecus classification, Gene Products, env chemistry, Gene Products, env genetics, HIV Antibodies blood, HIV-1 genetics, Human Immunodeficiency Virus Proteins, Humans, Molecular Sequence Data, Phylogeny, RNA, Viral blood, RNA, Viral isolation & purification, Recombination, Genetic, Sequence Analysis, DNA, Simian Immunodeficiency Virus genetics, Viral Regulatory and Accessory Proteins chemistry, Viral Regulatory and Accessory Proteins genetics, Cercopithecus virology, Genome, Viral, Simian Acquired Immunodeficiency Syndrome virology, Simian Immunodeficiency Virus classification
- Abstract
A novel simian immunodeficiency virus (SIV) sequence has been recovered from RNA extracted from the serum of a mona monkey (Cercopithecus mona) wild born in Nigeria. The sequence was obtained by using novel generic (degenerate) PCR primers and spans from two-thirds into the gag gene to the 3' poly(A) tail of the SIVmonNG1 RNA genome. Analysis of the open reading frames revealed that the SIVmonNG1 genome codes for a Vpu protein, in addition to Gag, Pol, Vif, Vpr, Tat, Rev, Env, and Nef proteins. Previously, only lentiviruses infecting humans (human immunodeficiency virus type 1 [HIV-1]) and chimpanzees (SIVcpz) were known to have a vpu gene; more recently, this has also been found in SIVgsn from Cercopithecus nictitans. Overall, SIVmonNG1 most closely resembles SIVgsn: the env gene sequence groups with HIV-1/SIVcpz env sequences, whereas the pol gene sequence clusters closely with the pol sequence of SIVsyk from Cercopithecus albogaris. By bootscanning and similarity plotting, the first half of pol resembles SIVsyk, whereas the latter part is closer to SIVcol from Colobus guereza. The similarities between the complex mosaic genomes of SIVmonNG1 and SIVgsn are consistent with a shared or common lineage. These data further highlight the intricate nature of the relationships between the SIVs from different primate species and will be helpful for unraveling these associations.
- Published
- 2003
- Full Text
- View/download PDF
32. Highly divergent HIV type 1 group M sequences evident in Karonga District, Malawi in early 1980s.
- Author
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McCormack GP, Glynn JR, Crampin AC, Sibande F, Mulawa D, Fine PE, and Clewley JP
- Subjects
- Genes, env genetics, Genes, gag genetics, HIV Infections virology, Humans, Malawi epidemiology, Molecular Sequence Data, Sequence Analysis, DNA, Genetic Variation, HIV Infections epidemiology, HIV-1 classification, HIV-1 genetics
- Abstract
Six divergent HIV-1 partial env and gag genome sequences have been characterized in five subjects in Malawi, from whom blood spot samples were collected between 1982 and 1989, at the time that the AIDS epidemic there was starting. These sequences could not be classified with any of the recognized subtypes or circulating recombinant forms of HIV-1. They showed no consistent and/or supported associations with other subtypes by either env or gag gene phylogenetic analysis. Their genetic distances from defined subtypes suggest that they may be diverse subsubtype C viruses or, alternatively, that they may have mosaic genomes. Bootscanning analyses are consistent with their being mosaic viruses. These sequences highlight early HIV-1 diversity in a population otherwise dominated by subtype C.
- Published
- 2003
- Full Text
- View/download PDF
33. The Holy Grail of the catch-all PCR.
- Author
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Clewley JP
- Subjects
- Communicable Diseases microbiology, Communicable Diseases virology, DNA, Bacterial analysis, DNA, Viral analysis, Humans, RNA, Bacterial analysis, RNA, Viral analysis, Communicable Diseases diagnosis, Polymerase Chain Reaction methods
- Published
- 2003
34. Non-invasive diagnostics in man and other primates.
- Author
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Clewley JP
- Subjects
- Animals, DNA, Viral analysis, HIV-1, Humans, RNA, Viral analysis, Reverse Transcriptase Polymerase Chain Reaction, Simian Immunodeficiency Virus, HIV Infections diagnosis, Microbiological Techniques, Primates, Simian Acquired Immunodeficiency Syndrome diagnosis
- Published
- 2002
35. Early evolution of the human immunodeficiency virus type 1 subtype C epidemic in rural Malawi.
- Author
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McCormack GP, Glynn JR, Crampin AC, Sibande F, Mulawa D, Bliss L, Broadbent P, Abarca K, Pönnighaus JM, Fine PE, and Clewley JP
- Subjects
- Adult, Amino Acid Sequence, Female, Genes, env, Genes, gag, HIV Envelope Protein gp120 chemistry, HIV-1 genetics, HIV-1 isolation & purification, Humans, Malawi, Male, Molecular Sequence Data, Phylogeny, Time Factors, HIV-1 classification
- Abstract
We have tracked the early years of the evolution of the human immunodeficiency virus type 1 (HIV-1) epidemic in a rural district of central east Africa from the first documented introductions of subtypes A, D, and C to the present predominance of subtype C. The earliest subtype C sequences ever reported are described. Blood samples were collected on filter papers from 1981 to 1984 and from 1987 to 1989 from more than 44,000 individuals living in two areas of Karonga District, Malawi. These samples included HIV-1-positive samples from 200 people. In 1982 to 1984, HIV-1 subtypes A, C, and D were all present, though in small numbers. By 1987 to 1989, 152 (90%) of a total of 168 sequences were subtype C and AC, AD, and DC recombinants had emerged. Four of the subtype C sequences from 1983 to 1984 were closely related and were found at the base of a large cluster of low diversity that by the late 1980s accounted for 40% of C sequences. The other two early C sequences fell into a separate and more diverse cluster. Three other clusters containing sequences from the late 1980s were identified. Each cluster contained at least one sample from a person who had recently arrived in the district. From 18 HIV-1-positive spouse pairs, 12 very closely related pairs of sequences were identified. We conclude that there were multiple introductions of HIV-1 with limited spread, followed by explosive growth of a subtype C cluster, probably arising from a single introduction in or before 1983.
- Published
- 2002
- Full Text
- View/download PDF
36. Virulence typing of Escherichia coli using microarrays.
- Author
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van Ijperen C, Kuhnert P, Frey J, and Clewley JP
- Subjects
- Carbocyanines, DNA Probes genetics, Escherichia coli genetics, Escherichia coli isolation & purification, Escherichia coli Infections diagnosis, Fluorescent Dyes, Glass, Humans, Polymerase Chain Reaction methods, Polymerase Chain Reaction standards, Sensitivity and Specificity, Virulence genetics, Escherichia coli pathogenicity, Oligonucleotide Array Sequence Analysis
- Abstract
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.
- Published
- 2002
- Full Text
- View/download PDF
37. Genomotyping: comparative bacterial genomics using arrays.
- Author
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Clewley JP
- Subjects
- Humans, In Vitro Techniques, Bacterial Typing Techniques, DNA, Bacterial analysis, Genome, Bacterial, Oligonucleotide Array Sequence Analysis methods
- Published
- 2002
38. The application of molecular phylogenetics to the analysis of viral genome diversity and evolution.
- Author
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McCormack GP and Clewley JP
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Humans, Molecular Sequence Data, Sequence Alignment, Sequence Analysis, DNA methods, Software, Virology methods, Virus Diseases transmission, Virus Diseases virology, Viruses classification, Evolution, Molecular, Genetic Variation, Genome, Viral, Phylogeny, Viruses genetics
- Abstract
DNA sequencing and molecular phylogenetics are increasingly being used in virology laboratories to study the transmission of viruses. By reconstructing the evolutionary history of viral genomes the behaviour of viral populations can be modelled, and the future of epidemics may be forecast. The manner in which such viral DNA sequences are analysed is the focus of this review. Many researchers resort to the often-quoted 'black box' approach because phylogenetics theory can be daunting, and phylogenetics software packages can appear to be difficult to use. However, because phylogenetic analyses are often used in important and sensitive arenas, for example to provide evidence indicating transmission between persons, it is vital that appropriate care is taken to estimate reliably true relationships. In this review, we discuss how a molecular phylogenetics study should be approached, give an overview of the methods and programs for analysing DNA sequence data, and point readers to appropriate texts for further details. The aim of this review, therefore, is to provide researchers with an easy to understand guide to molecular phylogenetics, with special reference to viral genomes., (Copyright 2002 John Wiley & Sons, Ltd.)
- Published
- 2002
- Full Text
- View/download PDF
39. Any diagnostic tests for vCJD yet?
- Author
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Clewley JP
- Subjects
- Creutzfeldt-Jakob Syndrome epidemiology, Humans, Sensitivity and Specificity, United Kingdom epidemiology, Creutzfeldt-Jakob Syndrome diagnosis, Reagent Kits, Diagnostic
- Published
- 2002
40. Biotech versus bioterror.
- Author
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Clewley JP
- Subjects
- Genetic Engineering, Humans, Variola virus genetics, Variola virus pathogenicity, World Health Organization, Biotechnology, Bioterrorism, Smallpox pathology
- Published
- 2002
41. Flu from the grave.
- Author
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Clewley JP
- Subjects
- Bioterrorism, Cadaver, Genes, Viral, Global Health, Humans, Influenza, Human epidemiology, Influenza, Human genetics, Research, Reverse Transcriptase Polymerase Chain Reaction, United Kingdom, Virulence, Orthomyxoviridae pathogenicity
- Published
- 2001
42. Selecting aptamers--the way to find a fit.
- Author
-
Clewley JP
- Subjects
- Base Composition, Binding Sites, Gene Library, In Vitro Techniques, Ligands, Nucleic Acid Amplification Techniques, Nucleic Acid Conformation, Protein Binding, Genes, Synthetic, Oligonucleotides chemical synthesis, Sequence Analysis, DNA methods, Sequence Analysis, RNA methods
- Published
- 2001
43. Data mining, endogenous retroviruses and human disease.
- Author
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Clewley JP
- Subjects
- Humans, Endogenous Retroviruses genetics, Genome, Human
- Published
- 2001
44. National surveillance of HIV-1 subtypes for England and Wales: design, methods, and initial findings.
- Author
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Parry JV, Murphy G, Barlow KL, Lewis K, Rogers PA, Belda FJ, Nicoll A, McGarrigle C, Cliffe S, Mortimer PP, and Clewley JP
- Subjects
- Acute Disease, Adult, Algorithms, England epidemiology, Female, Genotype, HIV Infections complications, HIV-1 genetics, Humans, Male, RNA, Viral analysis, Risk Factors, Serotyping, Sexuality, Sexually Transmitted Diseases complications, Sexually Transmitted Diseases virology, Substance Abuse, Intravenous complications, Substance Abuse, Intravenous virology, Wales epidemiology, HIV Infections epidemiology, HIV Infections virology, HIV-1 classification
- Abstract
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.
- Published
- 2001
- Full Text
- View/download PDF
45. Recombinant strains of HIV type 1 in the United Kingdom.
- Author
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Barlow KL, Tatt ID, Cane PA, Pillay D, and Clewley JP
- Subjects
- Cluster Analysis, Genes, env, Genes, gag, Genes, pol, HIV Infections epidemiology, Humans, Molecular Sequence Data, Phylogeny, United Kingdom epidemiology, HIV Infections virology, HIV-1 genetics, Recombination, Genetic
- Abstract
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.
- Published
- 2001
- Full Text
- View/download PDF
46. DNA tags.
- Author
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Clewley JP
- Subjects
- Humans, Nucleic Acid Amplification Techniques methods, Communicable Diseases diagnosis, Polymerase Chain Reaction methods
- Abstract
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.
- Published
- 2001
47. The public health significance of HIV-1 subtypes.
- Author
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Tatt ID, Barlow KL, Nicoll A, and Clewley JP
- Subjects
- HIV Infections virology, HIV-1 genetics, Humans, Genetic Variation, HIV Infections epidemiology, HIV-1 classification, Population Surveillance methods, Public Health
- Published
- 2001
- Full Text
- View/download PDF
48. Recombinant protein arrays.
- Author
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Clewley JP
- Subjects
- Gene Expression Profiling, Humans, Molecular Probe Techniques, Oligonucleotide Array Sequence Analysis, Peptide Library, RNA, Messenger, Antigen-Antibody Reactions, Recombinant Proteins analysis
- Published
- 2000
49. Characterization of a highly divergent TT virus genome.
- Author
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Hallett RL, Clewley JP, Bobet F, McKiernan PJ, and Teo CG
- Subjects
- DNA Virus Infections epidemiology, DNA, Viral chemistry, Humans, Molecular Sequence Data, Nucleic Acid Conformation, Open Reading Frames genetics, Phylogeny, Prevalence, United Kingdom epidemiology, DNA Virus Infections genetics, Genome, Viral, Torque teno virus genetics
- Abstract
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.
- Published
- 2000
- Full Text
- View/download PDF
50. Viral genome characterisation by the heteroduplex mobility and heteroduplex tracking assays.
- Author
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Barlow KL, Green J, and Clewley JP
- Subjects
- DNA, Viral analysis, DNA, Viral genetics, Humans, Mutation, RNA Virus Infections virology, RNA, Viral, Genome, Viral, Heteroduplex Analysis methods, RNA Viruses classification, RNA Viruses genetics
- Abstract
The heteroduplex mobility assay (HMA) is a means of comparing two PCR amplicons or, in the variation known as the heteroduplex tracking assay (HTA), a means of estimating the quasispecies diversity of a viral genome. Heteroduplex assays have many applications including subtyping viral genomes, screening for low frequency variants in a population, scanning the relative genetic diversity across a genome and screening for recombinant clones. They can be used to detect dual infections, superinfections, contaminated blood products and laboratory contaminations. PCR amplicons of about 65% sequence similarity or greater will form heteroduplexes under appropriate conditions, and phylogenetic trees can be drawn from heteroduplex mobility data. While homoduplexes indicate more than 98% similarity between two DNA sequences, heteroduplexes indicate at least seven mismatches in a 500-bp amplicon, or a three-base pair gap in 1000-bp. Minority variants comprising 1% to 5% of the genome population can be detected and quantified by HTA. Thus far, heteroduplex assays have been described for HIV and other lentiviruses, hepatitis C and G viruses, Norwalk-like viruses, influenza, measles and poliovirus. They could be applied to a wide range of other viral species., (Copyright 2000 John Wiley & Sons, Ltd.)
- Published
- 2000
- Full Text
- View/download PDF
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