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Biomedical subjects

M O'Sullivan

Publications and source records attributed to M O'Sullivan.

At least 19 recordsLinked to original sources
PubMed2006

White matter damage on diffusion tensor imaging correlates with age-related cognitive decline.

BACKGROUND: Damage to white matter tracts, resulting in "cerebral disconnection," may underlie age-related cognitive decline. METHODS: Using diffusion tensor MRI (DTI) to investigate white matter damage, and magnetic resonance spectroscopy (MRS) to look at its underlying pathologic basis, the authors investigated the relationship between white matter structure and cognition in 106 healthy middle-aged and elderly adults. Fractional anisotropy (FA) and mean diffusivity (MD) values, whole brain white matter histograms, and regions of interest placed in the white matter of the centrum semiovale were analyzed. Correlations with executive function, working memory, and information-processing speed were performed. RESULTS: There was a progressive reduction in FA and increase in diffusivity with age in both region of interest (r = 0.551, p < 0.001), and whole brain histograms (r = 0.625, p < 0.001). DTI values correlated with performance in all three cognitive domains. After controlling for age, DTI parameters correlated with working memory but not with the other two cognitive domains. MRS studies found a correlation of N-acetyl aspartate, a neuronal marker, with DTI parameters (r = 0.253, p < 0.05). CONCLUSION: The results are consistent with white matter damage due to axonal loss, causing age- related cognitive decline. Working memory may be particularly dependent on complex networks dependent on white matter connections.

Aged↗
PubMed2006

Attitudes of general dental practitioners in Europe to the microbial risk associated with dental unit water systems.

UNLABELLED: Dental Unit Water Systems (DUWS) are used in dental practices to provide water for cooling of dental equipment and irrigation of the oral cavity. However, they have been demonstrated to be contaminated with micro-organisms. There are currently no European Union (EU) Commission guidelines for the microbial quality of water discharged by DUWS. This study was part of an EU research programme to investigate the microbial contamination of DUWS in general dental practice (GDP) in the UK, Denmark, Germany, The Netherlands, Ireland, Greece and Spain. OBJECTIVE: To undertake a questionnaire survey on the type of DUWS in use and determine the attitude of GDPs to the risk of microbial infection from DUWS. MATERIALS AND METHODS: The questionnaire was written and translated into the language of each country before being posted to each participating dentist. Dentists were asked to complete the questionnaire survey and return it by post. RESULTS AND CONCLUSIONS: The major findings were that the majority of dentists did not clean, disinfect or determine the microbial load of their DUWS, and that dentists would welcome regular monitoring and advice on maintaining their DUWS; the introduction of guidelines; and recommendations on controlling the microbial load of DUWS.

Attitude of Health Personnel↗
PubMed2006

Comparison of the efficacies of disinfectants to control microbial contamination in dental unit water systems in general dental practices across the European Union.

Water delivered by dental unit water systems (DUWS) in general dental practices can harbor high numbers of bacteria, including opportunistic pathogens. Biofilms on tubing within DUWS provide a reservoir for microorganisms and should be controlled. This study compared disinfection products for their ability to meet the American Dental Association's guideline of <200 CFU x ml(-1) for DUWS water. Alpron, BioBlue, Dentosept, Oxygenal, Sanosil, Sterilex Ultra, and Ster4Spray were tested in DUWS (n = 134) in Denmark, Germany, Greece, Ireland, The Netherlands, Spain, and the United Kingdom. Weekly water samples were tested for total viable counts (TVCs) on yeast extract agar, and, where possible, the effects of products on established biofilm (TVCs) were measured. A 4- to 5-week baseline measurement period was followed by 6 to 8 weeks of disinfection (intermittent or continuous product application). DUWS water TVCs before disinfection ranged from 0 to 5.41 log CFU x ml(-1). Disinfectants achieved reductions in the median water TVC ranging from 0.69 (Ster4Spray) to 3.11 (Dentosept) log CFU x ml(-1), although occasional high values (up to 4.88 log CFU x ml(-1)) occurred with all products. Before treatment, 64% of all baseline samples exceeded American Dental Association guidelines, compared to only 17% following commencement of treatment; where tested, biofilm TVCs were reduced to below detectable levels. The antimicrobial efficacies of products varied (e.g., 91% of water samples from DUWS treated with Dentosept or Oxygenal met American Dental Association guidelines, compared to 60% of those treated with Ster4Spray). Overall, the continuously applied products performed better than those applied intermittently. The most effective products were Dentosept and Oxygenal, although Dentosept gave the most consistent and sustained antimicrobial effect over time.

Biofilms↗
PubMed2005

Damage within a network of white matter regions underlies executive dysfunction in CADASIL.

OBJECTIVE: To identify the important sites of white matter disruption that underpin executive dysfunction in CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), a genetic model of pure subcortical vascular disease. METHODS: The anatomic pattern of correlation between tissue integrity and executive function was explored with diffusion tensor imaging (DTI), which provides quantitative measures of tissue integrity. Eighteen nondemented patients with CADASIL underwent DTI and cognitive assessment. DTI was normalized to a standard template and correlations assessed at every voxel across the brain with Statistical Parametric Mapping with cluster-level correction for multiple comparisons. RESULTS: For executive tasks, correlations were found in a number of discrete regions in the white matter of the frontal lobes. A distinct, nonoverlapping pattern of correlation was seen for verbal memory. Significant independent correlations remained in some regions after co-varying for age and IQ. CONCLUSIONS: Different cognitive functions correlate with structural integrity at different sites in the white and subcortical gray matter. The distribution of regions correlating specifically with executive function provides clues to the organization of the relevant cognitive networks and their important white matter projections. The cingulum bundle is one candidate tract that may carry anteroposterior connections important for executive processes.

Adult↗
PubMed2005

Obstetric risk factors for urinary incontinence and preventative pelvic floor exercises: cohort study and nested randomized controlled trial.

We conducted a cohort study assessing risk factors for developing urinary incontinence following childbirth, and a pilot randomized controlled trial of a physiotherapist-led intervention to reduce incidence of incontinence. A total of 723 women were recruited to the cohort study, of which 234 entered the nested trial and were randomized to intensive training in pelvic floor exercises or standard information. At 6 months post-partum, 45% of women reported some incontinence problems. A pre-existing incontinence problem was the best predictor of future incontinence (odds ratio 4.49, 95% confidence interval (CI) 3.09-6.53). Chronic constipation (1.86, 1.03-3.34) and episiotomy in at least one delivery (1.96, 1.25-3.07) were also independent risk factors, while an epidural or spinal (0.62, 0.42-0.92) was protective. The intervention as designed did not help in preventing future incontinence (relative risk 1.28, 95% CI 0.98-1.67), but this may be due to the failure to persuade the women to return for the classes. Any intervention aimed at promoting postnatal pelvic floor exercises should be limited to women who have already been experiencing incontinence problems.

Chronic Disease↗
PubMed2005

A characterization of anaerobic colonization and associated mucosal adaptations in the undiseased ileal pouch.

INTRODUCTION: The resolution of pouchitis with metronidazole points to an anaerobic aetiology. Pouchitis is mainly seen in patients with ulcerative colitis pouches (UCP). We have recently found that sulphate reducing bacteria (SRB), a species of strict anaerobe, colonize UCP exclusively. Herein, we aimed to correlate levels of different bacterial species (including SRB) with mucosal inflammation and morphology. METHODS: Following ethical approval, fresh faecal samples and mucosal biopsies were taken from 9 patients with UCP and 5 patients with familial adenomatous polyposis pouches (FAPP). For the purposes of comparison, faecal samples and mucosal biopsies were also taken from the stomas of 7 of the 9 patients with UC (UCS). Colonization by four types of strict anaerobes (SRB, Clostridium perfringens, Bifidobacteria and Bacteroides) as well as by three types of facultative anaerobes (Enterococci, Coliforms and Lactobacilli) was evaluated. Inflammatory scores and mucosal morphology were assessed histologically in a blinded fashion by a pathologist. RESULTS: In general, strict anaerobes predominated over facultative in the UCP (P = 0.041). SRB were present in UCP exclusively. Even after exclusion of SRB from total bacterial counts, strict anaerobes still predominated. In the UCS, facultative anaerobes predominated. Strict and facultative anaerobes were present at similar levels in the FAPP. Enterococci were present at significantly reduced levels in the UCP when compared with the UCS (P = 0.031). When levels of SRB and other anaerobic species were individually correlated with mucosal inflammation and morphology, no trends were observed. CONCLUSION: We have previously identified that SRB exclusively colonize UCP. In addition we have now identified a novel increase in the strict/facultative anaerobic ratio within the UCP compared to UCS. These stark differences in bacterial colonization, however, appear to have limited impact on mucosal inflammation or morphology.

Adenomatous Polyposis Coli↗
PubMed2005

Brief cognitive assessment for patients with cerebral small vessel disease.

BACKGROUND: Cerebral small vessel disease is a common cause of cognitive impairment and vascular dementia. The cognitive deficit differs from that in Alzheimer's disease, with greater executive/attentional dysfunction and relatively intact episodic memory. OBJECTIVE: To develop brief assessment tools that are better adapted to the neuropsychological profile of cerebral small vessel disease. METHODS: 32 subjects with ischaemic leukoaraiosis (history of lacunar stroke and leukoaraiosis on MRI), aged 50 to 84 years, and 17 age and education matched controls had a brief executive assessment, which took 20 minutes to administer, and a wide range of additional tests. The ability of the brief executive assessment to discriminate between groups-both individually and in combination-was evaluated and compared with that of the whole battery. RESULTS: The brief executive assessment provided good sensitivity and specificity for identifying subjects with ischaemic leukoaraiosis (sensitivity 88%, specificity 88%, using the optimal combination of scores). The best individual tests were trail making and digit symbol, which were both far more sensitive than the mini-mental state examination (MMSE). The ability to discriminate between groups was maintained in subjects with MMSE > 27 and across the whole age range. The brief executive assessment performed well compared with the whole battery, with additional tests accounting for only a further 12% of between-group variance. CONCLUSIONS: The brief executive assessment was sensitive to deficits found in ischaemic leukoaraiosis and discriminated them from the cognitive effects of healthy aging. The assessment has potential for bedside use and as a cognitive end point for clinical trials.

Aged↗
PubMed2005

Microbial contamination of dental unit water systems.

INTRODUCTION: Dental unit water systems (DUWS) may serve as a reservoir for biofilms that contribute to high numbers of bacteria in the water used during dental treatment. These microbes are predominantly harmless but potentially pathogenic organisms can also be present in the biofilm. This may pose a potential health risk for patients and dental personnel. AIM: to determine the microbial levels of DUWS in dental practices. MATERIALS AND METHOD: A cross-sectional study of water and tubing samples from 30 general dental practices (15 health board and 15 private surgeries) was undertaken as part of a pan-European investigation of the microbial qualitative and quantitative aspects of DUWS. RESULTS: Microbial loads ranged from 100 to 104 cfu ml-1 and exceeded the European guidelines for drinking water in many cases. The available evidence suggested the presence of isolates most likely belonging to families of aquatic and soil bacteria. It was not possible to draw distinct conclusions correlating microbial loads with dental unit parameters, including age of the unit, water source and chemistry and presence or absence of anti-retraction devices. Opportunistic or true pathogens were not detected. Yeasts were observed in samples from three units although further analysis confirmed that these were not Candida albicans. A decontamination strategy applied to one of the units eliminated the yeasts completely. CONCLUSIONS: Dental practitioners must be knowledgeable regarding microbial contamination and biofilm formation in dental unit waterlines. There is a need for development of European evidence-based guidelines and reliable control regimes for microbial contamination of DUWS.

Biofilms↗
PubMed2005

Attitudes of Irish and European dentists to water quality of dental unit water systems.

BACKGROUND: Dental unit water systems (DUWS) are used in dental practices to provide water to irrigate the oral cavity. Dental surgeries across the European Union (EU) use DUWS that may be prone to microbial contamination. OBJECTIVES: To determine Irish dental practitioners' attitudes to perceived risk from working with DUWS and their protocols for the management of biofilm in their DUWS and compare these with other European dentists. DESIGN: A questionnaire was used to determine DUWS types in use, practitioners' attitudes to risks associated with using DUWS and their DUWS management protocols. RESULTS: There were six different types of DUWS, 40 per cent of which were > 5 years old, 42 per cent of DUWS were fed by purified or distilled water. Only four per cent of practitioners carried out microbiological analysis on their water, but 38 per cent indicated that they cleaned or disinfected their DUWS. One-hundred per cent of practitioners were not aware of national/international guidelines for microbial contamination of DUWS but 77 per cent were concerned about DUWS water quality. CONCLUSIONS: The majority of practitioners were working with equipment that is < 5 years old. The majority of DUWS were not treated but practitioners were concerned about dental unit water quality and would welcome regular microbiological water tests and clear advice on cleaning/disinfection of the water supply in their dental units. Practitioner attitudes and behaviours were broadly similar in the other European countries studied.

Attitude of Health Personnel↗
PubMed2004

Endothelial nitric oxide gene haplotypes and risk of cerebral small-vessel disease.

BACKGROUND AND PURPOSE: Genetic influences are important in multifactorial cerebral small-vessel disease (SVD) and may act via endothelial dysfunction. Nitric oxide (NO) synthesized by endothelial nitric oxide synthase (eNOS) is a key mediator of endothelial function. We determined the role of 3 potentially functional eNOS polymorphisms (T-786C, intron 4ab, G894T) located toward the 5' flanking end of the gene as risk factors for SVD and different SVD subtypes: isolated lacunar infarction (n=137) and ischemic leukoaraiosis (n=160). METHODS: Three hundred patients with SVD and 600 community controls were studied. Genotypes were determined through polymerase chain reaction with or without restriction fragment digestion. Nitrate (NO(x)) levels were determined in a subgroup by use of a Griess method. Polymorphisms were tested individually and in combination with haplotype analysis. RESULTS: The intron 4a variant was protective against SVD. This effect was confined to isolated lacunar infarction (odds ratio, 0.55; 95% confidence interval, 0.35 to 0.86; P=0.01). Haplotypes encountered were significantly different in this subtype compared with controls (P=0.001), with the -786C promoter/intron 4a combination particularly underrepresented. NO(x) levels were associated with the T-786C locus (P=0.03) but only in the presence of the intron 4a allele (P=0.07 for interaction). CONCLUSIONS: The intron 4ab insertion/deletion genotype was associated with isolated lacunar infarction. Haplotype and functional studies suggested that the protective effect of the 4a variant could be mediated through changes in eNOS promoter activity and increased NO levels. The specific association with isolated symptomatic lacunar infarction and not ischemic leukoaraiosis may reflect different etiopathogeneses of the 2 subtypes. Lack of NO could predispose to localized microatheroma in proximal arterioles rather than diffuse arteriosclerosis affecting distal perforating vessels.

Aged↗
PubMed2004

NOD2/CARD15, TLR4 and CD14 mutations in Scottish and Irish Crohn's disease patients: evidence for genetic heterogeneity within Europe?

NOD2/caspase recruitment domain (CARD)15 variants are identified in up to 50% of Crohn's disease (CD) patients. Functional variants of toll-like receptor-4 (TLR4) and CD14 genes may also be relevant to disease pathophysiology. We aimed to assess the contribution of NOD2/CARD15, TLR4 and CD14 variants in Scottish and Irish CD patients. In all, 612 patients with well-characterised inflammatory bowel disease (252 Scottish CD, 247 Scottish UC, 113 Irish CD) and 304 controls were genotyped for variants of NOD2/CARD15 (1007fsinsC, G908R, R702W, P268S), TLR4 (A299G) and CD14 (T-159C). Genotype-phenotype analyses were performed. Variant 1007fsinsC (P=0.003) and G908R (P=0.008) but not R702W (P=0.269) alleles were more prevalent in Scottish CD (4.7, 1.8 and 7.1%, respectively) than Scottish control (2.3, 0.3 and 5.4%). CD allelic frequencies were lower than the series from Europe (P<0.00001) and North America (P<0.00001) but not Scandinavia (P<0.7). Associations were identified with age at diagnosis (P=0.002), ileal disease (P<0.02), penetrating disease (P=0.04) and inflammatory joint disease (P<0.02). TLR4 and CD14 variants did not differ between CD and controls. In conclusion, we present compelling evidence for genetic heterogeneity within Europe. These NOD2/CARD15 variants have a minor contribution in Scottish and Irish CD patients, consistent with an emerging pattern from Northern Europe.

Adult↗
PubMed2004

Microbiological evaluation of dental unit water systems in general dental practice in Europe.

A range of opportunistic pathogens have been associated with dental unit water systems (DUWS), particularly in the biofilms that can line the tubing. This study therefore aimed to assess the microbiology of DUWS and biofilms in general dental practices across seven European countries, including the United Kingdom (UK), Ireland (IRL), Greece (GR), Spain (ES), Germany (D), Denmark (DK) and the Netherlands (NL). Water supplied by 51% of 237 dental unit water lines exceeded current American Dental Association recommendations of < or = 200 colony-forming units (CFU) ml(-1). Microbiological loading of the source waters was between 0 (Denmark, the Netherlands and Spain) and 4.67 (IRL) log CFU ml(-1); water line samples from the DUWS ranged from 1.52 (ES) to 2.79 (GR) log CFU ml(-1); and biofilm counts ranged from 1.49 (GR) to 3.22 (DK) log CFU.cm(-2). Opportunistic pathogens such as legionellae (DK and ES), including Legionella pneumophila SG1 (DK and GR), and Mycobacterium spp. (DK, NL, GR, D and ES) were recovered occasionally. Presumptive oral streptococci (ES and NL), oral anaerobes (GR), Candida spp. (UK, NL and ES) and blood (GR and IRL) were detected at relatively low frequencies, but their presence indicated a failure of the 3-in-1 antiretraction valve, leading to back siphonage of oral fluids into the water and biofilm phase. These findings confirm that a substantial proportion of DUWS have high levels of microbial contamination, irrespective of country, type of equipment and source water. The study emphasizes the need for effective mechanisms to reduce the microbial burden within DUWS, and highlights the risk of occupational exposure and cross-infection in general dental practice.

Bacteria↗
PubMed2004

Diffusion tensor MRI correlates with executive dysfunction in patients with ischaemic leukoaraiosis.

BACKGROUND: Cerebral small vessel disease is a common cause of vascular dementia. Both discrete lacunar infarcts and more diffuse ischaemic changes, seen as confluent high signal (leukoaraiosis) on T2 weighted magnetic resonance imaging (MRI), occur. However, there is a weak correlation between T2 lesion load and cognitive impairment. Diffusion tensor MRI (DTI) is a new technique that may provide a better index of white matter damage. OBJECTIVES: To determine whether DTI measures are correlated more strongly with cognitive performance than lesion load on T2 weighted images, and whether these correlations are independent of conventional MRI parameters. METHODS: 36 patients with ischaemic leukoaraiosis (leukoaraiosis plus a previous lacunar stroke) and 19 healthy volunteers underwent DTI, conventional MRI, and neuropsychological assessment. RESULTS: On DTI, diffusivity was increased both within lesions and in normal appearing white matter. Mean diffusivity of normal appearing white matter correlated with full scale IQ (r = -0.46, p = 0.009) and tests of executive function. These correlations remained significant after controlling for age, sex, brain volume, and T1/T2 lesion volumes. No significant correlation was identified between T2 lesion load and IQ or neuropsychological scores. Of conventional measures, brain volume correlated best with cognitive function. CONCLUSIONS: Diffusion tensor measurements correlate better with cognition than conventional MRI measures. They may be useful in monitoring disease progression and as a surrogate marker for treatment trials. The findings support the role of white matter damage and disruption of white matter connections in the pathogenesis of cognitive impairment in cerebral small vessel disease.

Aged↗
PubMed2003

Minimally displaced Colles' fractures: a prospective randomized trial of treatment with a wrist splint or a plaster cast.

Sixty-six adult patients with minimally displaced distal radial fractures were randomly assigned to treatment with either a plaster cast or a lightweight removable wrist splint. Outcome assessment was by clinical and radiological evaluation and an independent physiotherapy assessment. There were significant differences between the treatments for cast satisfaction, cast problems and the functional assessment score at 6 weeks, with the removable splint scoring better in all cases.

Activities of Daily Living↗
PubMed2003

SAPHO syndrome presenting as septic arthritis in the hip.

We report the case of a young female presenting to our care with right hip pain. Initially treated as a septic arthritis, there was no response to antibiotic treatment. Further clinical and radiological investigation showed signs of SAPHO syndrome. This is a syndrome characterised by the variable presentation of synovitis, acne, pustulosis, hyperostosis and osteitis. The patient subsequently settled on conservative management and made a full recovery.

Acquired Hyperostosis Syndrome↗