Biomedical subjects

Caroline Clark

Publications and source records attributed to Caroline Clark.

7 recordsLinked to original sources

PubMed2006

The C677T polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR), maternal use of folic acid supplements, and risk of isolated clubfoot: A case-parent-triad analysis.

Worldwide, 1-4 per 1,000 births are affected by clubfoot. Clubfoot etiology is unclear, but both genetic and environmental factors are thought to be involved. Low folate status in pregnant women has been implicated in several congenital malformations, and folate metabolism may be affected by polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR). Using a case-parent-triad design, the authors investigated whether the MTHFR C677T polymorphism, and maternal periconceptional folic acid supplement use, influenced risk of isolated clubfoot. Three hundred seventy-five United Kingdom case-parent triads were recruited in 1998-1999. Among the children, there was a significant trend of decreasing clubfoot risk with increasing number of T alleles: relative risk for CT vs. CC = 0.75, 95% confidence interval: 0.57, 0.97; relative risk for TT vs. CC = 0.57, 95% confidence interval: 0.35, 0.91; p trend = 0.006. This association was not modified by maternal folic acid use. Maternal MTHFR genotype did not influence clubfoot risk for the offspring overall, although a possible interaction with folic acid use was found. This is the first known report of a specific genetic polymorphism associated with clubfoot. The direction of the association is intriguing and suggests that DNA synthesis may be relevant in clubfoot development. However, clubfoot mechanisms are poorly understood, and the folate metabolism pathway is complex. Further research is needed to elucidate these relations.

Adolescent↗

PubMed2006

Genotyping Hepatitis B virus from whole- and sub-genomic fragments using position-specific scoring matrices in HBV STAR.

Hepatitis B virus (HBV) genomes have been classified into eight genotypes based on phylogenetic analysis of sequence variation. Identifying and tracking the movement of HBV genotypes is important in terms of both monitoring infection rates and predicting disease and treatment. An HBV genotyping tool has been developed that compares query sequences with position-specific scoring matrices representing the eight HBV genotypes. This tool (hbv star) is rapid, robust and accurate and assigns genotype based on a statistically defined scoring model. hbv star confidently assigned 90% of 590 full-length HBV genomes to an HBV genotype (Z score >2.0). Thirty-two of the residual 48 sequences were identified as non-human primate viruses and 16 sequences were identified as recombinant or putative recombinants. Receiver-Operated Characteristic (ROC) analysis was used to compare the accuracy of genotype prediction using basal core promoter sequences and surface and core genes with the accuracy achieved by using full-length sequences. A web interface to hbv star is available at http://www.vgb.ucl.ac.uk/starn.shtml.

Animals↗

PubMed2004

Vitamin D receptor, HER-2 polymorphisms and risk of prostate cancer in men with benign prostate hyperplasia.

OBJECTIVE: Prostate cancer (PRCa) is one of the most common causes of cancer death in men and determinants of PRCa risk remain largely unidentified. Benign prostatic hyperplasia (BPH) is found in the majority of ageing men and has been associated with PRCa. Many candidate genes have been suggested to be involved in PRCa, such as those that are central to cellular growth and differentiation in the prostate gland. The vitamin D receptor (VDR) and HER-2 protooncogene have been shown to be involved in the regulation of cell proliferation and differentiation in prostate cells. Genetic variations of these genes could be useful to detect BPH patients that have a higher risk of developing PRCa. This study used a case-control design to assess the predictive value of 3 polymorphisms in VDR (TaqI and FokI) and HER-2 (Val655Ile) to determine the risk of developing PRCa in patients with BPH. METHODS: Polymorphisms were detected by RFLP analysis. The study evaluated 28 patients who presented with PRCa at least 6 years after the diagnosis of BPH and 56 matched patients with BPH who did not progress to PRCa over a comparable period. The study was carried out in University of Aberdeen, Foresterhill, Aberdeen, United Kingdom in the year 2002. RESULTS: Among the case group, 89% had a TT TaqI genotype, whereas 57% of control had this genotype (odds ratio [OR] = 5.16, 95% confidence interval [CI] = 1.46-18.22). A similar pattern was seen for the FokI genotype, although this was not statistically significant (OR = 2.33, 95% CI = 0.86-6.29). The frequency of the HER-2 Ile/Ile genotype was higher in cases (79%) compared to control subjects (66%), although this was not statistically significant (OR = 1.94, 95% CI = 0.67-5.63). CONCLUSION: This study shows that the VDR TaqI polymorphism is associated with a group of men with BPH who are at an increase risk of PRCa, providing a potential tool to assist prediction strategies for this important disease.

Case-Control Studies↗

PubMed2003

SARS: a health system's perspective.

Effective communications with different stakeholders was critical for health systems everywhere during the worldwide SARS outbreak earlier this year. For Capital Health in Edmonton, Alberta, the health system was able to build on its past experiences in dealing with meningococcal outbreaks and its planning for a pandemic flu.

Alberta↗

PubMed2002

Gastric fundic gland polyps in south-east Scotland: absence of adenomatous polyposis coli gene mutations and a strikingly low prevalence of Helicobacter pylori infection.

BACKGROUND AND AIM: Fundic gland polyps (FGP) were originally described in association with familial polyposis syndromes, but it is now accepted that the majority of FGP are picked up incidentally in up to 1.9% of routine endoscopies in dyspeptic patients. The familial adenomatous polyposis phenotype arises from germline mutations of the adenomatous polyposis coli (APC) gene. We aimed to see if there was any association between the presence of FGP, Helicobacter pylori, and two common APC gene mutations. METHODS: From a search of histopathology records in our unit, 85 consecutive patients were identified with a definite histological diagnosis of FGP between 1989 and 1997. Case notes could be retrieved in 48 cases to show the indication for endoscopy and endoscopic findings. Twenty-six patients (mean age 61 years, range 40-83 years) were tested for H. pylori status, and for the 1306 and 1061 bp deletions of the APC gene by the use of an enzyme-linked immunoassay and polymerase chain reaction techniques, respectively. RESULTS: Eighty-nine percent of patients underwent an endoscopy because of dyspepsia; 4.2% were anaemic, 4.2% had hematemesis and 1.2% had dysphagia. Only one patient was seropositive for H. pylori and no patient carried either APC gene deletion. CONCLUSIONS: This genetic information on those with FGP confirms previous phenotypic studies in that the majority of FGP are not associated with familial polyposis syndromes. The significance of such a strikingly low incidence of H. pylori infection in a dyspeptic population remains unclear.

Adenomatous Polyposis Coli↗

PubMedDate not supplied

Length and somatic mosaicism of CAG and GGN repeats in the androgen receptor gene and the risk of prostate cancer in men with benign prostatic hyperplasia.

BACKGROUND: The most common malignancy in men worldwide is cancer of the prostate and determinants of prostate cancer (PRCa) risk remain largely unidentified. Many candidate genes may be involved in PRCa, such as those that are central to cellular growth and differentiation in the prostate gland. We analysed the polymorphic CAG and GGN repeats sequence in exon 1 of the AR gene to determine if the number of repeats might be an indicator of PRCa risk in patients with BPH. METHODS: The study evaluated 28 patients who presented with PRCa at least 6 years after the diagnosis of BPH and 56 matched patients with BPH who did not progress to PRCa over a comparable period. RESULTS: This study showed no evidence for association between the size of AR CAG and GGN repeats and the risk of the development of PRCa in patients with BPH. However, BPH patients with AR CAG instability had a 12-fold increased risk in development of PRCa. CONCLUSIONS: While independent confirmation is required in further studies, these results provide a potential tool to assist prediction strategies for this important disease.

Case-Control Studies↗

PubMedDate not supplied

CYP3A4 promoter variant is associated with prostate cancer risk in men with benign prostate hyperplasia.

Prostate cancer (PRCa) is one of the most common causes of cancer death in men and determinants of PRCa risk remain largely unidentified. Benign prostatic hyperplasia (BPH) is found in the majority of ageing men and has been linked with PRCa. CYP3A4 may influence PRCa through its role in testosterone metabolism. This nested case-control study assessed a CYP3A4 single nucleotide polymorphism as a risk factor for developing PRCa in patients with BPH. The CYP3A4 variant allele identified men with BPH who are at increased risk of progressing to PRCa (odds ratio 6.3, 95% CI 2.3-17.3), providing a potential tool to assist prediction strategies for this disease.

Alleles↗