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Colin Campbell

Publications and source records attributed to Colin Campbell.

At least 19 recordsLinked to original sources
PubMed2007

A novel interaction between DNA ligase III and DNA polymerase gamma plays an essential role in mitochondrial DNA stability.

The data in the present study show that DNA polymerase gamma and DNA ligase III interact in mitochondrial protein extracts from cultured HT1080 cells. An interaction was also observed between the two recombinant proteins in vitro. Expression of catalytically inert versions of DNA ligase III that bind DNA polymerase gamma was associated with reduced mitochondrial DNA copy number and integrity. In contrast, overexpression of wild-type DNA ligase III had no effect on mitochondrial DNA copy number or integrity. Experiments revealed that wild-type DNA ligase III facilitates the interaction of DNA polymerase gamma with a nicked DNA substrate in vitro, and that the zinc finger domain of DNA ligase III is required for this activity. Mitochondrial protein extracts prepared from cells overexpressing a DNA ligase III protein that lacked the zinc finger domain had reduced base excision repair activity compared with extracts from cells overexpressing the wild-type protein. These data support the interpretation that the interaction of DNA ligase III and DNA polymerase gamma is required for proper maintenance of the mammalian mitochondrial genome.

Binding Sites↗
PubMed2006

Cadmium availability to wheat grain in soils treated with sewage sludge or metal salts.

Grain Cd concentrations were determined in wheat (Triticum aestivum L.) grown in 1999, 2001 and 2003, at six sludge cake field experiments. Three of these sites also had comparisons with Cd availability from metal amended liquid sludge and metal salts. Grain Cd concentrations in all years and at all sites were significantly linearly correlated with NH4NO3 extractable Cd and soil total Cd (P<0.001). Soil extractability was greater in the liquid sludge and metal salt experiments than in the cake experiments, as were grain Cd concentrations. Across all the sites, NH4NO3 extractable soil Cd was no better at predicting grain Cd than soil total Cd. Stepwise multiple linear regression analysis showed that soil total Cd, pH and organic carbon were the only significant (P<0.001) variables influencing wheat grain Cd concentrations, explaining 78% of the variance across all field experiments (1408 plots). This regression predicted that the current UK soil total Cd limit of 3 mg kg(-1) was not sufficiently protective against producing grain above the European Union (EU) grain Cd Maximum Permissible Concentration (MPC) of 0.235 mg Cd kg(-1) dry weight, unless the soil pH was > 6.8. Our predictions show that grain would be below the MPC with > 95% confidence with the proposed new EU draft regulations permitting maximum total Cd concentrations in soils receiving sludge of 0.5 mg kg(-1) for soils of pH 5-6, 1 mg kg(-1) for soils of pH 6-7, and 1.5 mg kg(-1) for soils of pH > or = 7.

Cadmium↗
PubMed2006

Accurate prediction of BRCA1 and BRCA2 heterozygous genotype using expression profiling after induced DNA damage.

PURPOSE: In this study, the differential gene expression changes following radiation-induced DNA damage in healthy cells from BRCA1/BRCA1 mutation carriers have been compared with controls using high-density microarray technology. We aimed to establish if BRCA1/BRCA2 mutation carriers could be distinguished from noncarriers based on expression profiling of normal cells. EXPERIMENTAL DESIGN: Short-term primary fibroblast cultures were established from skin biopsies from 10 BRCA1 and 10 BRCA2 mutation carriers and 10 controls, all of whom had previously had breast cancer. The cells were subjected to 15 Gy ionizing irradiation to induce DNA damage. RNA was extracted from all cell cultures, preirradiation and at 1 hour postirradiation. For expression profiling, 15 K spotted cDNA microarrays manufactured by the Cancer Research UK DNA Microarray Facility were used. Statistical feature selection was used with a support vector machine (SVM) classifier to determine the best feature set for predicting BRCA1 or BRCA2 heterozygous genotype. To investigate prediction accuracy, a nonprobabilistic classifier (SVM) and a probabilistic Gaussian process classifier were used. RESULTS: In the task of distinguishing BRCA1 and BRCA2 mutation carriers from noncarriers and from each other following radiation-induced DNA damage, the SVM achieved 90%, and the Gaussian process classifier achieved 100% accuracy. This effect could not be achieved without irradiation. In addition, the SVM identified a set of BRCA genotype predictor genes. CONCLUSIONS: We conclude that after irradiation-induced DNA damage, BRCA1 and BRCA2 mutation carrier cells have a distinctive expression phenotype, and this may have a future role in predicting genotypes, with application to clinical detection and classification of mutations.

Adult↗
PubMed2006

A novel interaction [corrected] of nucleolin with Rad51.

Nucleolin associates with various DNA repair, recombination, and replication proteins, and possesses DNA helicase, strand annealing, and strand pairing activities. Examination of nuclear protein extracts from human somatic cells revealed that nucleolin and Rad51 co-immunoprecipitate. Furthermore, purified recombinant Rad51 associates with in vitro transcribed and translated nucleolin. Electroporation-mediated introduction of anti-nucleolin antibody resulted in a 10- to 20-fold reduction in intra-plasmid homologous recombination activity in human fibrosarcoma cells. Additionally, introduction of anti-nucleolin antibody sensitized cells to death induced by the topoisomerase II inhibitor, amsacrine. Introduction of anti-Rad51 antibody also reduced intra-plasmid homologous recombination activity and induced hypersensitivity to amsacrine-induced cell death. Co-introduction of anti-nucleolin and anti-Rad51 antibodies did not produce additive effects on homologous recombination or on cellular sensitivity to amsacrine. The association of the two proteins raises the intriguing possibility that nucleolin binding to Rad51 may function to regulate homologous recombinational repair of chromosomal DNA.

Amsacrine↗
PubMed2006

Neuroscience and legal determination of criminal responsibility.

Neuroscience is increasingly identifying associations between biology and violence that appear to offer courts evidence relevant to criminal responsibility. In addition, in a policy era of 'zero tolerance of risk', evidence of biological abnormality in some of those who are violent, or biological markers of violence, may be seized on as a possible basis for preventive detention in the interest of public safety. However, there is a mismatch between questions that the courts and society wish answered and those that neuroscience is capable of answering. This poses a risk to the proper exercise of justice and to civil liberties.

Antisocial Personality Disorder↗
PubMed2006

Evaluation of a pilot careers advice service for junior doctors.

This study evaluates a pilot careers service for junior doctors provided by a non-medical careers adviser. Evaluation forms and interviews indicate high satisfaction with this service. The junior doctors valued help with CVs and interviews, information regarding career routes and meetings with senior doctors arranged by the adviser. A longitudinal survey suggests that these doctors became clearer about their career pathways compared with controls, although they did not view the adviser as influencing their career choices. The employment of non-medical careers advisers is proposed. The evaluation was principally conducted by the Centre for Research in Medical and Dental Education, School of Education, University of Birmingham, UK.

Career Mobility↗
PubMed2005

Using the SWAP-200 in a personality-disordered forensic population: is it valid, reliable and useful?

BACKGROUND: Treatment and risk management of forensic patients relies heavily on diagnosing psychopathology, yet the reliability of clinical diagnoses of personality disorder has been found to be only fair to low. Structured instruments for the global assessment of personality disorder are infrequently used in clinical assessments possibly due to their limited validity and clinical utility. AIMS/METHODS: The Shedler-Westen Assessment Procedure-200 (SWAP-200) was developed in an effort to address these limitations. Although good reliability and validity in relation to clinicians' diagnosis of personality disorder has been reported, to date the validity of this instrument has not been assessed in relation to other standardized instruments or in a personality-disordered, forensic population. This study aims to establish the reliability and validity of the SWAP-200 against other diagnostic instruments and measures of interpersonal functioning in a personality disordered forensic population. RESULTS: This paper reports the results of 30 subjects from a high secure hospital in the UK who were assessed with the SWAP-200, the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II), the Adult Attachment Interview (AAI) and the Chart of Interpersonal Reactions in Closed Living Environments (CIRCLE). Preliminary results suggest that the SWAP-200 is a reliable instrument for the diagnosis of personality disorder in forensic patients. CONCLUSIONS: Although the small sample size allows only preliminary conclusions about the validity of this instrument, early results show a reduction of the diagnosis of comorbidity compared with the SCID-II, together with an increased number of expected associations between independent measures of interpersonal functioning and categories of personality disorder.

Adult↗
PubMed2005

Introducing 'Palcall': an innovative out-of-hours telephone service led by hospice nurses.

Palcall is an out-of-hours telephone service providing support and advice to palliative care patients, their carers and health professionals. Each patient who is registered with the scheme consents to named friends or relatives having access to the dedicated Palcall number. Telephone calls to the service are taken by the most senior palliative care nurse on duty in the hospice. The nurse has ready access to details of the medical condition and current medications of every patient who is registered. If required, the nurse can contact a more senior nursing colleague or the on-call hospice GP. The day following the telephone call, the Palcall administrator forwards written details to the patient's GP and any healthcare professional involved in the care of the patient. Quality control measures are in place to continually enhance the service.

After-Hours Care↗
PubMed2004

Intermediate DNA repair activity associated with the 322delG allele of the fanconi anemia complementation group C gene.

Fanconi anemia (FA) is an autosomal recessive disorder associated with pancytopenia and cancer susceptibility. The disorder is heterogeneous, with at least nine complementation groups having been identified. Several recent studies have suggested that defective plasmid DNA end-joining is a consistent feature of FA cells. It was therefore surprising to discover a strain of fibroblasts from an FA patient that possessed wild-type plasmid DNA end-joining activity. Unlike other FA strains, these fibroblasts have wild-type levels of homologous DNA recombination activity and are relatively insensitive to restriction endonuclease-induced death. Interestingly, while end-joining in a number of FA fibroblast strains belonging to complementation groups A, C, and D2 was approximately 70% precise, end-joining in this latter strain of fibroblasts was more than 95% imprecise. Analysis revealed that these latter cells harbored an allele of the FA C gene, referred to as 322delG, that encodes an amino-terminal truncated protein. The relative rarity of this allele precluded the analysis of other FA fibroblast strains; however, studies revealed that overexpression of this allele in normal cells recapitulated the DNA end-joining phenotype seen in the 322delG FA fibroblast strain. These results indicate that DNA end-joining in fibroblasts expressing the 322delG allele of the FA-C gene in fibroblasts is highly imprecise; however, the DNA repair efficiency of these cells is more normal than that commonly associated with FA fibroblasts. This conclusion is intriguing, since a number of reports have suggested that patients harboring this allele exhibit a milder clinical course than do individuals with other alleles of the FA-C gene.

Alleles↗
PubMed2004

A Rad50-dependent pathway of DNA repair is deficient in Fanconi anemia fibroblasts.

Fanconi anemia (FA) is a fatal genetic disorder associated with pancytopenia and cancer. Cells lacking functional FA genes are hypersensitive to bifunctional alkylating agents, and are deficient in DNA double-strand break repair. Multiple genes with FA-causing mutations have been cloned, however, the molecular basis for FA remains obscure. The results presented herein indicate that a Rad50-dependent end-joining process is non-functional in diploid fibroblasts from FA patients. Introduction of anti-Rad50 antibody into normal fibroblasts sensitized them to DNA damaging agents, whereas this treatment had no effect on fibroblasts from FA patients. The DNA end-joining process deficient in FA cells also requires the Mre11, Nbs1 and DNA ligase IV proteins. These data reveal the existence of a previously uncharacterized Rad50-dependent DNA double-strand break repair pathway in mammalian somatic cells, and suggest that failure to activate this pathway is responsible, at least in part, for the defective DNA end-joining observed in FA cells.

Acid Anhydride Hydrolases↗
PubMed2004

Gene expression profiling after radiation-induced DNA damage is strongly predictive of BRCA1 mutation carrier status.

PURPOSE: The impact of the presence of a germ-line BRCA1 mutation on gene expression in normal breast fibroblasts after radiation-induced DNA damage has been investigated. EXPERIMENTAL DESIGN: High-density cDNA microarray technology was used to identify differential responses to DNA damage in fibroblasts from nine heterozygous BRCA1 mutation carriers compared with five control samples without personal or family history of any cancer. Fibroblast cultures were irradiated, and their expression profile was compared using intensity ratios of the cDNA microarrays representing 5603 IMAGE clones. RESULTS: Class comparison and class prediction analysis has shown that BRCA1 mutation carriers can be distinguished from controls with high probability (approximately 85%). Significance analysis of microarrays and the support vector machine classifier identified gene sets that discriminate the samples according to their mutation status. These include genes already known to interact with BRCA1 such as CDKN1B, ATR, and RAD51. CONCLUSIONS: The results of this initial study suggest that normal cells from heterozygous BRCA1 mutation carriers display a different gene expression profile from controls in response to DNA damage. Adaptations of this pilot result to other cell types could result in the development of a functional assay for BRCA1 mutation status.

Ataxia Telangiectasia Mutated Proteins↗
PubMed2004

Prognostic classification of relapsing favorable histology Wilms tumor using cDNA microarray expression profiling and support vector machines.

Treatment of Wilms tumor has a high success rate, with some 85% of patients achieving long-term survival. However, late effects of treatment and management of relapse remain significant clinical problems. If accurate prognostic methods were available, effective risk-adapted therapies could be tailored to individual patients at diagnosis. Few molecular prognostic markers for Wilms tumor are currently defined, though previous studies have linked allele loss on 1p or 16q, genomic gain of 1q, and overexpression from 1q with an increased risk of relapse. To identify specific patterns of gene expression that are predictive of relapse, we used high-density (30 k) cDNA microarrays to analyze RNA samples from 27 favorable histology Wilms tumors taken from primary nephrectomies at the time of initial diagnosis. Thirteen of these tumors relapsed within 2 years. Genes differentially expressed between the relapsing and nonrelapsing tumor classes were identified by statistical scoring (t test). These genes encode proteins with diverse molecular functions, including transcription factors, developmental regulators, apoptotic factors, and signaling molecules. Use of a support vector machine classifier, feature selection, and test evaluation using cross-validation led to identification of a generalizable expression signature, a small subset of genes whose expression potentially can be used to predict tumor outcome in new samples. Similar methods were used to identify genes that are differentially expressed between tumors with and without genomic 1q gain. This set of discriminators was highly enriched in genes on 1q, indicating close agreement between data obtained from expression profiling with data from genomic copy number analyses.

Adolescent↗
PubMed2003

NMDA-evoked consumption and recovery of mitochondrially targeted aequorin suggests increased Ca2+ uptake by a subset of mitochondria in hippocampal neurons.

Activation of NMDA receptors produces large increases in cytosolic Ca(2+) that are taken up into mitochondria. We used recombinant aequorin targeted to mitochondria to report changes in matrix Ca(2+) in rat hippocampal neurons in culture. Upon binding Ca(2+), aequorin emits a photon in a one-shot reaction that consumes the indicator. Here we show that stimulation with NMDA produced a mitochondrial Ca(2+) response that rapidly inactivated. However, following a 30-min recovery period the response was restored, suggesting the presence of a pool of indicator that was not exposed to high Ca(2+) during the initial stimulus. We speculate that aequorin distant from the Ca(2+) source was protected from microdomains of high Ca(2+) near the plasmalemma and that this aequorin moved, either by movement of individual mitochondria or via the mitochondrial tubular network, to replenish consumed indicator during the recovery time. A large Ca(2+) increase in a subset of mitochondria could produce local changes in energy metabolism, regional Ca(2+) buffering, and foci that initiate neurotoxic processes.

Aequorin↗
PubMed2003

Deficient regulation of DNA double-strand break repair in Fanconi anemia fibroblasts.

Fibroblasts from patients with Fanconi anemia (FA) display genomic instability, hypersensitivity to DNA cross-linking agents, and deficient DNA end joining. Fibroblasts from two FA patients of unidentified complementation group also had significantly increased cellular homologous recombination (HR) activity. Results described herein show that HR activity levels in patient-derived FA fibroblasts of groups A, C, and G were 10-fold greater than those seen in normal fibroblasts. In contrast, HR activity in group D2 fibroblasts was identical to that in normal cells. Western blot analysis revealed that the RAD51 protein was elevated 10-fold above normal levels in group A, C, and G fibroblasts, but was not altered in group D2 fibroblasts. HR activity levels in these former cells could be restored to near-normal levels by electroporation with anti-RAD51 antibody, whereas similar treatment of normal and complementation group D2 fibroblasts had no effect. These findings are consistent with a model in which FA proteins function to coordinate DNA double-strand break repair activity by regulating both recombinational and non-recombinational DNA repair. Interestingly, whereas positive regulation of DNA end joining requires the combined presence of all FA proteins thus far tested, suppression of HR, which is minimally dependent on the FANCA, FANCC, and FANCG proteins, does not require FANCD2.

Animals↗