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Gillian Smith

Publications and source records attributed to Gillian Smith.

At least 19 recordsLinked to original sources
PubMed2006

Developing a national primary care-based early warning system for health protection--a surveillance tool for the future? Analysis of routinely collected data.

The increasing threat of infections with pandemic potential such as influenza has focussed attention on the information needed to inform those managing a pandemic. The Health Protection Agency, Nottingham University and EMIS have developed a new national health protection surveillance system using QRESEARCH, an established primary care-derived database, to provide timely and local information on trends in community illness and prescribing. This article describes the first year of the surveillance project. Data on consultations and prescribing were extracted from routinely generated computerized consultation records between November 2004 and December 2005. Weekly consultation and prescribing rates for a range of conditions including influenza-like illness and prescription of anti-viral drugs for influenza and vomiting were developed as 'key indicators'. These indicators were presented in a weekly bulletin showing data to strategic health authority level for use by those working in public health. The particular value of this scheme is the ability to produce timely data on illness to local level and to link prescribing to morbidity. The data were used 'real time' to reassure about lack of illness following the Buncefield Fuel Depot incident. This scheme is being further developed to provide daily local influenza-related information needed in an influenza pandemic.

Ambulatory Care Information Systems↗
PubMed2006

Cardiovascular magnetic resonance, fibrosis, and prognosis in dilated cardiomyopathy.

OBJECTIVES: We studied the prognostic implications of midwall fibrosis in dilated cardiomyopathy (DCM) in a prospective longitudinal study. BACKGROUND: Risk stratification of patients with nonischemic DCM in the era of device implantation is problematic. Approximately 30% of patients with DCM have midwall fibrosis as detected by late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR), which may increase susceptibility to arrhythmia and progression of heart failure. METHODS: Consecutive DCM patients (n = 101) with the presence or absence of midwall fibrosis were followed up prospectively for 658 +/- 355 days for events. RESULTS: Midwall fibrosis was present in 35% of patients and was associated with a higher rate of the predefined primary combined end point of all-cause death and hospitalization for a cardiovascular event (hazard ratio 3.4, p = 0.01). Multivariate analysis showed midwall fibrosis as the sole significant predictor of death or hospitalization. However, there was no significant difference in all-cause mortality between the 2 groups. Midwall fibrosis also predicted secondary outcome measures of sudden cardiac death (SCD) or ventricular tachycardia (VT) (hazard ratio 5.2, p = 0.03). Midwall fibrosis remained predictive of SCD/VT after correction for baseline differences in left ventricular ejection fraction between the 2 groups. CONCLUSIONS: In DCM, midwall fibrosis determined by CMR is a predictor of the combined end point of all-cause mortality and cardiovascular hospitalization, which is independent of ventricular remodeling. In addition, midwall fibrosis by CMR predicts SCD/VT. This suggests a potential role for CMR in the risk stratification of patients with DCM, which may have value in determining the need for device therapy.

Adult↗
PubMed2006

Chromosomal changes in colorectal adenomas: relationship to gene mutations and potential for clinical utility.

Although the occurrence of both chromosomal aberrations and specific gene mutations in colorectal tumorigenesis is firmly established, the relationship between these different forms of genetic abnormality remains poorly understood. We have previously demonstrated, in colorectal adenocarcinomas, that mutations of APC, KRAS, and TP53 are each specifically associated with certain chromosomal aberrations. Using comparative genomic hybridization and mutational analysis of APC, KRAS, and TP53 to evaluate 78 colorectal adenomas, we have shown that several of the significant relationships between gene mutations and chromosomal abnormalities reported in colorectal adenocarcinomas also exist at the adenomatous stage. KRAS mutation correlated with 12p gain (P < 0.001) and TP53 mutation with both 20q gain and 18q loss (P = 0.03 for both). In addition, we have identified two chromosomal aberrations, gain of 13q and loss of 11q, that correlate with the presence of synchronous adenomas (P = 0.049 and P = 0.03, respectively) and several chromosomal changes (20p+, 20q+, 17p-, and 18q-) that are related to the onset of high-grade dysplasia. These data strengthen our previous contention that the co-occurrence of specific gene mutations and chromosomal changes is not random and significant relationships do exist. Our findings also raise the possibility that certain chromosomal aberrations may act as important clinical biomarkers.

Adenoma↗
PubMed2006

T2* effects in the dual-sequence method for high-dose first-pass myocardial perfusion.

PURPOSE: To examine whether T2* effects reduce the accuracy of arterial input function (AIF) measurement by the dual-sequence method. MATERIALS AND METHODS: The dual-sequence method obtains a low-resolution AIF image and high-resolution myocardial images in each cycle, with suitable T1 weightings. It was modified to assess T2* effects in the low-resolution AIF image (4.8x4.8x10 mm voxels, TE=0.58 msec) by minimizing T1 weighting in that sequence, while the myocardial sequence remained T1-weighted. In 10 patients who underwent perfusion MRI scans (0.5 M Magnevist, 0.1 mmol/kg, 15-ml flush, 7 mL/second right antecubital) the blood signal in the left ventricle (LV) was measured at the bolus peak and compared with the first cycle's fresh magnetization signal. RESULTS: The bolus peak measured 98%+/-4% (mean+/-SD, N=20) of the value before contrast agent arrival. CONCLUSION: T2* causes insignificant error in the dual-sequence method at the stated parameters.

Algorithms↗
PubMed2005

No evidence that polymorphisms in CYP2C8, CYP2C9, UGT1A6, PPARdelta and PPARgamma act as modifiers of the protective effect of regular NSAID use on the risk of colorectal carcinoma.

OBJECTIVES: Regular continuous non-steroidal anti-inflammatory drug (NSAID) use has been associated with a reduction in risk of colorectal cancer. Our objective was to investigate whether or not a number of the polymorphic genes involved in the metabolism of NSAIDs, including cytochrome P450 s (CYPs), act as modifiers of this protective effect. METHODS: As part of a multi-centre case-control study, 478 colorectal cancer patients and 733 controls (433 matched case-control pairs) answered questions on NSAID use. These individuals were then genotyped for common polymorphisms in P450 CYP2C8, P450 CYP2C9, UDP-glucuronosyl transferase (UGT)1A6 and peroxisome proliferator-activated receptor isoforms delta and gamma (PPARdelta and PPARgamma). RESULTS AND CONCLUSION: Our study confirmed the reduction in risk of colorectal cancer with regular NSAID use (odds ratio (OR) = 0.73, 95% confidence interval (CI) (0.56, 0.95)) but showed that none of the polymorphic genes studied appeared to modify the protective effect of regular NSAID use.

Aged↗
PubMed2005

Identification of a functionally impaired allele of human novel oxidoreductase 1 (NDOR1), NDOR1*1.

OBJECTIVES: Human novel oxidoreductase 1 (NDOR1) is a diflavin reductase closely related to cytochrome P450 reductase (POR) and nitric oxide synthase (NOS), which are involved in the metabolism of antitumour agents. A variant cDNA sequence of NDOR1, NDOR1 p.518-519ins9 or NDOR1_v1, has been deposited in GenBank (accession no. AK026089 and AY077845) that encodes an additional nine amino acids, which led us to investigate NDOR1 polymorphism. METHODS AND RESULTS: We analysed genomic DNA from 200 Caucasian and 49 Japanese individuals by PCR--restriction fragment length polymorphism analysis. The nine amino acid residue sequence was found to be present in all individuals, encoded by a 27 nt intronic nucleotide sequence at an intron/exon junction, suggesting that this variant did not represent a common genetic polymorphism, but may have arisen from an alternative mRNA splicing event. However, further analysis of NDOR1 revealed a polymorphic c.1564G>A transition (NDOR1*1), detected in 24/200 Caucasian and 1/49 Japanese individuals, producing a valine to isoleucine substitution at codon 522 in the NADPH binding region. Expression of the flavin adenine dinucleotide/reduced nicotinamide phosphate dehydrogenase (NADPH) domain in Escherichia coli showed a significant 74% reduction in potassium ferricyanide reductase activity, but no effect on NADPH binding. NDOR1_v1 showed a 10-fold decrease in affinity for NADPH, and a 90% reduction in ferricyanide reductase activity. CONCLUSIONS: We have discovered a polymorphic variant of NDOR1, NDOR1*1, that produces a functionally impaired enzyme. This will help define the structure and function of NDOR1 and its relationship to cancer and other diseases.

Alleles↗
PubMed2005

Localization of cytochrome P450 CYP2S1 expression in human tissues by in situ hybridization and immunohistochemistry.

CYP2S1 is a recently discovered dioxin-inducible member of the cytochrome P450 superfamily. It has been shown to be involved in the metabolism of some aromatic hydrocarbons as well as retinoic acid, suggesting a role in biotransformation of both exogenous and endogenous compounds. In this study, we used mRNA in situ hybridization and immunohistochemistry to investigate the cellular localization of CYP2S1 in various human tissues using tissue microarrays. High expression levels were observed mainly in epithelial cell types, especially in the epithelia frequently exposed to xenobiotics. In the respiratory tract, the expression was strong in nasal cavity, bronchi, and bronchioli, whereas it was low in the alveolar lining cells. Similarly, CYP2S1 was highly expressed in the epithelial cells throughout the gastrointestinal tract. Strong epithelial expression was also observed in uterine cervix, urinary bladder, and skin. In many exocrine glands (e.g., adrenal gland and pancreas), secretory epithelial cells showed moderate to strong expression levels. In the liver, the expression was low. CYP2S1 was highly expressed in epithelial cells that are major targets for carcinogen exposure and common progenitor cells to tumor development. Indeed, we found strong CYP2S1 expression in many tumors of epithelial origin.

Cytochrome P-450 Enzyme System↗
PubMed2005

The effect of deprivation, age and sex on NHS Direct call rates.

BACKGROUND: The use of primary care services in the UK is traditionally high in deprived areas. There has been little research into the effect of deprivation on the uptake of NHS Direct, a national nurse-led health helpline. AIM: To explore the impact of deprivation, age and sex on call rates to two NHS Direct sites. DESIGN OF STUDY: Ecological study. SETTING: West Yorkshire and West Midlands NHS Direct sites. METHOD: Details of NHS Direct calls between July 2001 and January 2002 were linked to electoral wards and the Indices of Multiple Deprivation for 2000. Age-standardised call rates were calculated for five deprivation levels. Using a negative binomial regression model, West Yorkshire call rates were analysed by age group, sex, deprivation level and geographical location. Rates were mapped by ward for West Yorkshire NHS Direct. RESULTS: Six-monthly call rates were highest for children under 5 years of age (130 per 1000 population). The ratio of female to male calls (all ages) was 1.30 (95% confidence interval [CI] = 1.27 to 1.33), this ratio being highest for the 15-44 year age group (P < 0.001). For both West Yorkshire and West Midlands NHS Direct, call rates (all ages combined) were highest in areas within the middle of the range of deprivation. West Yorkshire call rates about those under 5 years of age were lower in the most deprived areas than in the least deprived areas (< 1 year, P = 0.06; 1-4 years, P = 0.03). For adults aged 15-64 years, call rates were significantly higher in the most deprived areas (P < 0.001). CONCLUSION: This work supports previous research and shows that overall demand for NHS Direct is highest in areas where deprivation is at or just above the national average. Additionally, this study suggests that the effect of extreme deprivation appears to raise adult call rates but reduce rates of calls about children.

Adolescent↗
PubMed2004

Vegetable, fruit and meat consumption and potential risk modifying genes in relation to colorectal cancer.

Epidemiological evidence shows high red meat consumption to increase the risk of colorectal cancer, while the consumption of fruit and vegetables has been shown to be protective. Many genes have been identified that encode for enzymes involved in the metabolism of dietary carcinogens or anti-carcinogens. A study of 500 incident colorectal cancer cases and population controls, matched for age, sex and general practitioner, was conducted in the United Kingdom to investigate whether 6 such genes (CYP1A1, GSTT1, GSTM1, GSTP1, EPHX1 and NQO1) modify the relationship between diet and disease risk. Usual diet was estimated using a detailed questionnaire administered by interview. Fruit and vegetable consumption were both found to protect against colorectal cancer, while overall meat and red meat consumption were found to increase risk. There was some evidence of interaction between GSTT1 and vegetable consumption (p=0.006, not adjusted for multiple tests) but no evidence of interaction with GSTM1. The protective effect of vegetables was only seen in those with deficient or intermediate GSTT1 predicted phenotype [OR 0.3, 95% confidence interval (0.1, 0.6), and OR 0.6 (0.4, 0.96), OR 1.4 (0.3, 2.4) for those with fast phenotype], and a similar result was observed for cruciferous vegetables. There was also weak evidence of interaction between red meat intake and GSTT1 (p=0.06), GSTP1 (p=0.16, with p=0.02 after adjustment for potential confounders) and NQO1 predicted phenotype (p=0.01). Because of the multiple hypotheses tested in our study, these findings require independent confirmation.

Aged↗
PubMed2004

Phenotyping of N-acetyltransferase type 2 by caffeine from uncontrolled dietary exposure.

BACKGROUND AND OBJECTIVE: The standard approach for phenotyping of the human arylamine N-acetyltransferase 2 (NAT2) uses urinary caffeine metabolite ratios after a caffeine test dose taken in after methylxanthine abstinence. We tested whether these standardization measures were still needed when a more sensitive quantification technique was used. METHODS: A new liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the quantification of the caffeine metabolites 5-acetylamino-6-formylamino-3-methyluracil (AFMU), 5-acetylamino-6-amino-3-methyluracil (AAMU), 1-methylxanthine (1X), and 1-methylurate (1U) was developed. Urine samples from 77 healthy volunteers collected before and 5-6 h after oral intake of 150-200 mg caffeine were analyzed. The lower limits of quantification were 0.1 microg/ml for caffeine, 1X, 1U, and AFMU, and 0.2 microg/ml for AAMU. RESULTS: The urinary NAT2 ratios (AFMU+AAMU) / (AFMU+AAMU+1X+1U) before and after caffeine intake correlated well in 65 volunteers (r(2)=0.827; P< 0.0001). In 12 participants (16%), metabolite concentrations in urine before caffeine intake were below the quantification limit. NAT2 genotyping, done in 41 volunteers for four SNPs, corroborated the phenotyping results. CONCLUSION: NAT2 activity can be determined from a spontaneous urine probe in most subjects by quantification of caffeine metabolites arising from non-standardized dietary caffeine exposure using LC-MS/MS. This may facilitate the phenotyping procedure.

Acetylation↗
PubMed2003

Mutations of APC, K-ras, and p53 are associated with specific chromosomal aberrations in colorectal adenocarcinomas.

It is widely accepted that both large-scale chromosomal abnormalities and mutation of specific genes, such as APC, K-ras, and/or p53, occur in the majority of colorectal adenocarcinomas. Whether or not a relationship exists between these different forms of genetic abnormalities was previously unknown. Using comparative genomic hybridization and mutational analysis of APC, K-ras, and p53 to evaluate 50 colorectal adenocarcinomas, we have shown that mutation of p53 is significantly associated with gain of 20q, 13q, and 8q and loss of 18q (P = 0.000, 0.02, 0.044, and 0.001, respectively). Conversely, APC mutation did not associate with any of the above-mentioned aberrations but did associate significantly with gain of 7p (P = 0.01). Gain of chromosomal arm 12p, although a less common aberration, was significantly associated with K-ras mutation (P = 0.011). The associations we have described should refine the search for candidate genes underlying chromosomal aberrations and assist in the definition of distinct pathways in colorectal tumorigenesis.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Cutaneous expression of cytochrome P450 CYP2S1: individuality in regulation by therapeutic agents for psoriasis and other skin diseases.

BACKGROUND: Treatment of common skin diseases such as psoriasis is complicated by differences between individuals in response to topical drug treatment and photochemotherapy. Individuality in hepatic expression of drug-metabolising enzymes is an important determinant of systemic drug handling; we investigated whether similar variation in cutaneous gene expression contributes to individuality in response to topical therapies. METHODS: We used quantitative real-time RT-PCR to demonstrate the expression in skin of a recently identified cytochrome P450, CYP2S1, in healthy volunteers (n=27) and patients with psoriasis (n=29). We also investigated regulation of CYP2S1 by ultraviolet radiation, psoralen-ultraviolet A (PUVA), and topical drugs used to treat psoriasis. FINDINGS: We found that CYP2S1 is expressed in skin and showed pronounced individuality in constitutive expression of the enzyme and its induction after ultraviolet irradiation or topical drug treatment. Cutaneous expression of CYP2S1 was induced by ultraviolet radiation, PUVA, coal tar, and all-trans retinoic acid; expression was significantly higher in lesional psoriatic skin than in adjacent non-lesional skin (geometric mean 3.38 [95% CI 2.64-4.34] times higher; p<0.0001), which implies that topical drugs are differentially metabolised in psoriatic plaque and non-lesional skin. We showed that all-trans retinoic acid is metabolised by CYP2S1, which has higher cutaneous expression than CYP26, previously described as the specific cutaneous P450 retinoic-acid-metabolising enzyme. INTERPRETATION: These findings increase our understanding of the interaction between therapeutic agents and the skin and suggest a functional role for CYP2S1 in the metabolism of topical drugs and in mediating the response to photochemotherapy in psoriasis.

Coal Tar↗
PubMed2003

Polymorphisms in the cytochrome P450 CYP1A2 gene (CYP1A2) in colorectal cancer patients and controls: allele frequencies, linkage disequilibrium and influence on caffeine metabolism.

AIMS: Several single nucleotide polymorphisms (SNPs) of the cytochrome P450 enzyme 1A2 gene (CYP1A2) have been reported. Here, frequencies, linkage disequilibrium and phenotypic consequences of six SNPs are described. METHODS: From genomic DNA, 114 British Caucasians (49 colorectal cancer cases and 65 controls) were genotyped for the CYP1A2 polymorphisms -3858G-->A (allele CYP1A2*1C), -2464T-->delT (CYP1A2*1D), -740T-->G (CYP1A2*1E and *1G), -164A-->C (CYP1A2*1F), 63C-->G (CYP1A2*2), and 1545T-->C (alleles CYP1A2*1B, *1G, *1H and *3), using polymerase chain reaction-restriction fragment length polymorphism assays. All patients and controls were phenotyped for CYP1A2 by h.p.l.c. analysis of urinary caffeine metabolites. RESULTS: In 114 samples, the most frequent CYP1A2 SNPs were 1545T-->C (38.2% of tested chromosomes), -164A-->C (CYP1A2*1F, 33.3%) and -2464T-->delT (CYP1A2*1D, 4.82%). The SNPs were in linkage disequilibrium: the most frequent constellations were found to be -3858G/-2464T/-740T/-164A/63C/1545T (61.8%), -3858G/-2464T/-740T/-164C/63C/1545C (33.3%), and -3858G/-2464delT/-740T/-164A/63C/1545C (3.51%), with no significant frequency differences between cases and controls. In the phenotype analysis, lower caffeine metabolic ratios were detected in cases than in controls. This was significant in smokers (n = 14, P = 0.020), and in a subgroup of 15 matched case-control pairs (P = 0.007), but it was not significant in nonsmokers (n = 100, P = 0.39). There was no detectable association between CYP1A2 genotype and caffeine phenotype. CONCLUSIONS: (i) CYP1A2 polymorphisms are in linkage disequilibrium. Therefore, only -164A-->C (CYP1A2*1F) and -2464T-->delT (CYP1A2*1D) need to be analysed in the routine assessment of CYP1A2 genotype; (ii) in vivo CYP1A2 activity is lower in colorectal cancer patients than in controls, and (iii) CYP1A2 genotype had no effect on phenotype (based on the caffeine metabolite ratio). However, this remains to be confirmed in a larger study.

Aged↗
PubMed2003

Quantitative real-time reverse transcription-polymerase chain reaction analysis of drug metabolizing and cytoprotective genes in psoriasis and regulation by ultraviolet radiation.

There are unpredictable inter-individual differences in response to ultraviolet radiation, used in the treatment of psoriasis and other common skin diseases. It is therefore essential that we attempt to identify phenotypic markers that correlate with individual treatment outcomes. Exposure of human skin to ultraviolet radiation results in the generation of reactive intermediates and oxidative stress. Hepatic drug metabolizing and cytoprotective genes are induced as an adaptive response to xenobiotics and reactive intermediates; as several of these genes are present in skin, we hypothesized that their cutaneous expression and regulation may be implicated in responses to ultraviolet radiation. We used quantitative real-time reverse transcription-polymerase chain reaction to investigate interindividual differences in the cutaneous expression of a variety of drug metabolizing and cytoprotective genes, including cytochrome P450s, glutathione S-transferases and drug transporters, and investigated the regulation of gene expression by ultraviolet radiation and in lesional psoriatic skin. We confirmed significant induction of cyclooxygenase 2 (mean 3.63-fold, range 0.14-22.6, p<0.0001) by ultraviolet radiation and showed more modest (approximately 2-fold) inductions of glutathione peroxidase, and novel inductions of glutathione S-transferase P1 and the drug transporter multidrug resistance associated protein-1. Glutathione S-transferase P1 (3.74-fold, 1.3-33.1, p<0.0001) and multidrug resistance associated protein-1 (4.06-fold, 1.3-24.8, p<0.0001) were also significantly increased in psoriatic plaque, as were P450 CYP2E1 (3.64-fold, 1-28.9 p<0.0001) and heme oxygenase-1 (10.19-fold, 2.9-49.7, p<0.0001), implying a differential adaptive response to oxidant exposure in lesional psoriatic skin. We found considerable interindividual variation in constitutive gene expression and inducibility, indicating that these genes may be associated with individuality in response to ultraviolet radiation.

Adult↗
PubMed2002

Mutations in APC, Kirsten-ras, and p53--alternative genetic pathways to colorectal cancer.

Colorectal cancer is one of the most significant causes of cancer death. A genetic model for colorectal cancer has been proposed in which the sequential accumulation of mutations in specific genes, including adenomatous polyposis coli (APC), Kirsten-ras (K-ras), and p53, drives the transition from healthy colonic epithelia through increasingly dysplastic adenoma to colorectal cancer. We have characterized tumor mutation spectra in a large cohort of colorectal cancer patients. In marked contrast to the predictions of the sequential model of mutation accumulation, only 6.6% of tumors were found to contain mutations in APC, K-ras, and p53, with 38.7% of tumors containing mutations in only one of these genes. The most common combination of mutations was p53 and APC (27.1%), whereas mutations in both p53 and K-ras were extremely rare. Statistical analysis (two-sided Fisher's exact test) confirmed that mutations in K-ras and p53 co-occurred less frequently than expected by chance (P < 0.01, Fisher's exact test). This finding suggests that these mutations lie on alternate pathways of colorectal tumor development. The heterogeneous pattern of tumor mutations in our patient cohort suggests that multiple alternative genetic pathways to colorectal cancer exist and that the widely accepted genetic model of cancer development is not representative of the majority of colorectal tumors.

Aged↗
PubMed2002

Factors influencing the cellular accumulation of SN-38 and camptothecin.

PURPOSE: The influence of biophysical factors (drug metabolism, transport proteins, and chemical stability) on the cellular accumulation of camptothecin (CPT) and SN-38 was examined. METHODS: Drug transporter RNA transcript levels were measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Intracellular drug accumulation, metabolism, and drug stability studies were all performed by HPLC. RESULTS: A panel of three human cell lines exhibiting different drug resistant phenotypes was investigated. HT29 colon cells glucuronidated SN-38 but did not express P-gp or MRP1 or 2. HCT116 colon cells expressed P-gp and MRP2 but did not catalyse conjugation. A2780 ovarian cells neither catalysed drug metabolism nor contained these drug transporters. In all lines, SN-38 lactone was rapidly taken up achieving peak concentrations at the earliest time point studied (5 min, 3.3-4.1 ng/10(6) cells). Subsequently, a fall in intracellular lactone concentration occurred, stabilising after 4 h at 0.48-1.18 ng/10(6) cells. No significant differences in intracellular levels of lactone were observed between the three cell lines with one exception: a twofold increase in HCT116 cells at 24 h. Stability studies in culture medium revealed that SN-38 lactone concentrations disappeared at the same rate regardless of whether cells were present, initially falling to reach equilibrium with the hydroxy acid by 4 h. Indeed, changes in intracellular lactone concentrations followed closely chemical stability profiles in media. Similar patterns of cellular retention and chemical degradation were observed with CPT. CONCLUSION: The major determinant of drug accumulation in three diverse cell line phenotypes was lactone chemical stability in culture medium.

Adenocarcinoma↗