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Biomedical subjects

L Thornton

Publications and source records attributed to L Thornton.

At least 19 recordsLinked to original sources
PubMed2005

Parents' knowledge of and attitude towards the primary childhood immunisations.

Parental knowledge of immunisation is essential to assist public health initiatives to increase the uptake rates. A cross-sectional survey design was employed to ascertain the knowledge and attitude of the primary childhood immunisations in randomly selected parents in a deprived inner-city area; 82% of 93 responded. Parents' reported uptake of immunisation was compared with general practitioner and official health board records. Respondents with a low standard of education (70% of respondents without a Leaving Certificate versus 44% with the Leaving Certificate p=0.06) and parenting alone (69% versus 49% of two-parent families p=0.07) were less aware of the severity of the diseases. Older parents (58%) questioned immunisation safety more than younger parents (28%), p=0.06. Full immunisation was reported by 91% of parents compared to 81% from the general practitioners records and 70% from health board figures. The poor correlation between parents' reported immunisation uptake and official immunisation sources could be improved through the use of personal identification numbers.

Adolescent↗
PubMed2004

The epidemiology of infectious syphilis in the Republic of Ireland.

In response to the increasing numbers of syphilis cases reported among men having sex with men (MSM) in Dublin, an Outbreak Control Team (OCT) was set up in late 2000. The outbreak peaked in 2001 and had largely ceased by late 2003. An enhanced syphilis surveillance system was introduced to capture data from January 2000. Between January 2000 and December 2003, 547 cases of infectious syphilis were notified in Ireland (415 were MSM). Four per cent of cases were diagnosed with HIV and 15.4% of cases were diagnosed with at least one other STI (excluding HIV) within the previous 3 months. The mean number of contacts reported by male cases in the 3 months prior to diagnosis was 4 (range 0-8) for bisexual contacts and 6 for homosexual contacts (range 1-90). Thirty one per cent of MSM reported having had recent unprotected oral sex and 15.9% of MSM reported having had recent unprotected anal sex. Sixteen per cent of cases reported having had sex abroad in the three months prior to diagnosis. The results suggest that risky sexual behaviour contributed to the onward transmission of infection in Dublin. The outbreak in Dublin could be seen as part of a European-wide outbreak of syphilis. The rates of co-infection with HIV and syphilis in Ireland are comparable with rates reported from other centres. There is a need to improve surveillance systems in order to allow real time evaluation of interventions and ongoing monitoring of infection trends.

Adolescent↗
PubMed2002

Outbreak of Vero cytotoxin-producing Escherichia coli O157 in a child day care facility.

In December 1998, an outbreak of Vero cytotoxin-producing Escherichia coli (VTEC) O157 in a crèche affected ten out of 45 children and one out of five staff members. Eight cases were symptomatic and three were asymptomatic. There were two asymptomatic adult family contacts of child cases. All specimens were identified as VTEC O157:H7, phage type 32. None of the cases were seriously ill and none developed haemolytic uraemic syndrome (HUS). One child continued to excrete the organism for 14 weeks. The origin of the outbreak was not found but epidemiological investigation was suggestive of person-to-person spread. All children and staff were screened and excluded from the crèche until microbiological clearance was obtained. An inspection of the crèche revealed overcrowding and inadequacies in cleaning and in the food preparation facilities. These problems were remedied before children were re-admitted to the crèche. This outbreak demonstrates the ease with which VTEC O157 can be transmitted between small children. Two specific features of this outbreak were notable: (1) the mild self-limiting nature of the illness and (2) the prolonged shedding of the bacterium by one child.

Adult↗
PubMed2001

Prevalence of antibodies to hepatitis B, hepatitis C, and HIV and risk factors in entrants to Irish prisons: a national cross sectional survey.

OBJECTIVES: To determine the prevalence of antibodies to hepatitis B core antigen, hepatitis C virus, and HIV in entrants to Irish prisons and to examine risk factors for infection. DESIGN: Cross sectional, anonymous survey, with self completed risk factor questionnaire and oral fluid specimen for antibody testing. SETTING: Five of seven committal prisons in the Republic of Ireland. PARTICIPANTS: 607 of the 718 consecutive prison entrants from 6 April to 1 May 1999. MAIN OUTCOME MEASURES: Prevalence of antibodies to hepatitis B core antigen, hepatitis C virus, and HIV in prison entrants, and self reported risk factor status. RESULTS: Prevalence of antibodies to hepatitis B core antigen was 37/596 (6%; 95% confidence interval 4% to 9%), to hepatitis C virus was 130/596 (22%; 19% to 25%), and to HIV was 12/596 (2%; 1% to 4%). A third of the respondents had never previously been in prison; these had the lowest prevalence of antibodies to hepatitis B core antigen (4/197, 2%), to hepatitis C (6/197, 3%), and to HIV (0/197). In total 29% of respondents (173/593) reported ever injecting drugs, but only 7% (14/197) of those entering prison for the first time reported doing so compared with 40% (157/394) of those previously in prison. Use of injected drugs was the most important predictor of antibodies to hepatitis B core antigen and hepatitis C virus. CONCLUSIONS: Use of injected drugs and infection with hepatitis C virus are endemic in Irish prisons. A third of prison entrants were committed to prison for the first time. Only a small number of first time entrants were infected with one or more of the viruses. These findings confirm the need for increased infection control and harm reduction measures in Irish prisons.

Adolescent↗
PubMed2001

Oral fluid collection by post for viral antibody testing.

BACKGROUND: The objective of this study was to estimate the prevalence of hepatitis B virus exposure (HBV) in the population of the Republic of Ireland, by using oral fluid (saliva) collection by post for hepatitis B anti-core antibody (anti-HBc). This paper discusses the methodological approach used and the strategies that were adopted to improve response rates. METHODS: The sampling frame used was the Register of Electors for Irish parliamentary elections. A multistage stratified cluster sample was taken, and a total of 962 households were selected nationally. A four-letter approach was employed for sample collection. Households received an initial letter outlining the purpose of the study. This was followed by a letter containing six swabs for oral fluid collection, along with easy-to-follow instructions. Non-respondents received two reminder letters, and were also telephoned where possible. A telephone helpline was provided. All testing was anonymous and unlinked. RESULTS: The study achieved a good household response rate (60.4%), and more than 98% of the 1738 specimens received were suitable for testing. The prevalence of anti-HBc in the Irish population was estimated to be 0.51%. The observed design effect was 1.29. DISCUSSION: From a review of the literature, this is the first study where a representative sample of a national population was asked to self-collect oral fluid samples and return these by post for serological testing. The technique may have many future applications in epidemiological research.

Adult↗
PubMed2001

Role of fatty acids in the recovery of cardiac function during resuscitation from hemorrhagic shock.

This study tested the hypothesis that removal of fatty acids as a fuel source would improve cardiac efficiency at the expense of reduced cardiac contractile function in the isolated working heart after hemorrhage-retransfusion. Non-heparinized male Sprague-Dawley rats were anesthetized with ketamine-xylazine and were hemorrhaged to a mean arterial blood pressure of 40 mmHg for 1 h. Two-thirds volume of shed blood was reinfused together with 0.9% NaCl in a volume equal to 2.3 times the shed blood volume, followed by continuous infusion of 0.9% NaCl at 10 mL/kg per h for 3 h. Hearts were removed and perfused in closed, recirculating working mode for 60 min to measure hydraulic work and cardiac efficiency. Rates of glycolysis and glucose oxidation were assessed with [5-3H/U-14C] glucose (11 mM) in the absence or presence of 0.4 mM palmitate. Compared to baseline measurements, hemorrhage-retransfusion significantly reduced arterial blood glucose (228+/-7 versus 118+/-12 mg/dL) and non-esterified fatty acid concentrations (0.36+/-0.01 versus 0.30+/-0.02 mM), while elevating blood lactate (0.8+/-0.1 versus 2.5+/-0.4 mM). Perfusion of sham hearts with glucose-only did not alter cardiac work compared to shams perfused with glucose plus palmitate. However, shocked hearts perfused with glucose-only demonstrated a significant reduction in cardiac work compared to shocked hearts perfused with glucose plus palmitate and compared to sham hearts perfused with glucose only (P < 0.05, repeated measures ANOVA). Shocked hearts perfused with glucose plus palmitate showed no reduction in cardiac work compared to shams. Shocked hearts perfused with glucose-only had increased glucose oxidation rates compared to shams perfused with glucose plus palmitate. In sham hearts perfused with glucose-only, myocardial glycogen and triacylglycerol contents were significantly reduced compared to hearts freeze-clamped in situ. These endogenous fuels were not decreased in shocked hearts. These data indicate that hemorrhagic shock renders the heart unable to mobilize endogenous fuels, and suggest that withdrawal of fatty acid oxidation will impair myocardial energy metabolism during resuscitation.

Animals↗
PubMed2000

Prevalence of antibodies to hepatitis B, hepatitis C, and HIV and risk factors in Irish prisoners: results of a national cross sectional survey.

OBJECTIVES: To determine the prevalence of antibodies to hepatitis B core antigen, hepatitis C virus, and HIV in the prison population of the Republic of Ireland and to examine risk factors for infection. DESIGN: Cross sectional, anonymous, unlinked survey, with self completed risk factor questionnaire and provision of oral fluid specimen for antibody testing. SETTING: Nine of the 15 prisons in the Republic of Ireland. PARTICIPANTS: 1366 prisoners, of whom 1205 (57 women) participated. In the smaller prisons all prisoners were surveyed, while in the three largest prisons one half of the population was randomly sampled. Three small prisons believed not to have a problem with injecting drug use were excluded. MAIN OUTCOME MEASURES: Prevalence of antibodies to hepatitis B core antigen, antibodies to hepatitis C virus, and antibodies to HIV. Self reported risk factor status. RESULTS: Prevalence of antibodies to hepatitis B core antigen was 104/1193 (8.7%; 95% confidence interval 7.2% to 10.5%), to hepatitis C virus, 442/1193 (37%; 34.3% to 39.9%), and to HIV, 24/1193 (2%; 1.3% to 3%). The most important predictor of being positive for hepatitis B and hepatitis C was a history of injecting drug use. Thirty four women (60%) and 474 men (42%) reported ever injecting drugs. A fifth (104) of 501 injecting drug users reported first injecting in prison, and 347 (71%) users reported sharing needles in prison. CONCLUSIONS: Infection with hepatitis C secondary to use of injected drugs is endemic in Irish prisons. Better access to harm reduction strategies is needed in this environment.

AIDS-Related Opportunistic Infections↗
PubMed2000

Prevalence of hepatitis B anti-core antibody in the Republic of Ireland.

The aim of this study was to estimate the prevalence of hepatitis B exposure in the population of the Republic of Ireland, by measuring the prevalence of hepatitis B anti-core antibody in oral fluid collected by postal survey. A random multi-stage stratified sample of Irish households was obtained, using the Irish electoral register as the sampling frame. A total of 962 households were selected, and a household response rate of 60.4% was achieved. Oral fluid specimens totalling 1714 were tested for antibody to hepatitis B core antigen (anti-HBc), using an Immune Capture Enzyme Immuno-Assay. Five specimens (0.29%) were found to contain anti-HBc. Adjusting for study design, the estimated anti-HBc prevalence in the Republic of Ireland is 0.51%. This study demonstrates that self-collection of oral fluid samples is acceptable to the public, and based upon the data generated, that the Republic of Ireland has a low prevalence of hepatitis B infection.

Adolescent↗
PubMed2000

Concentrations of antimony in infants dying from SIDS and infants dying from other causes.

OBJECTIVES: Raised concentrations of antimony have been found in infants dying of sudden infant death syndrome (SIDS). The presumed source of this antimony is toxic gases generated from fire retardants that are present in cot mattresses. The aim of this study was to determine the role of antimony in SIDS. DESIGN: Samples of liver, brain, serum, and urine were collected from all patients dying from SIDS and a group of aged matched control infants who had died of other causes. SETTING: Nationwide study in Ireland. SUBJECTS: 52 infants dying from SIDS and 19 control infants aged > 7 days and < 1 year. RESULTS: The median concentration of antimony in the liver and brain of infants dying of SIDS was < 1 ng/g, with no difference detected between the infants dying from SIDS and the control infants. The range of antimony in the serum of infants dying of SIDS was 0.09-0.71 microg/litre (median, 0.26). Although no difference was found between infants dying from SIDS and control infants, SIDS infants were found to have higher concentrations when compared with healthy infants in the 1st year of life, probably as a result of release of antimony into serum after death. Urine antimony concentrations in infants dying from SIDS were < 3.91 ng/mg (corrected for creatinine) and similar to values found both in control infants and healthy infants. CONCLUSION: There is no evidence to support a causal role for antimony in SIDS.

Antimony↗
PubMed2000

Comparison between self-reported hepatitis B, hepatitis C, and HIV antibody status and oral fluid assay results in Irish prisoners.

Self-reported hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV infection status was compared with the results of oral fluid assays of antibodies to these viruses in prisoners from nine of the 15 prisons in the Republic of Ireland. A total of 1205 out of 1366 prisoners completed a confidential questionnaire and 1193 provided analysable oral fluid specimens for testing for antibodies to HBV core antigen (anti-HBc), HCV (anti-HCV), and HIV (anti-HIV). The self-reported prevalence of hepatitis infection (hepatitis B: 5%; hepatitis C: 19%) was lower than that derived from oral fluid assays (anti-HBc: 9%; anti-HCV: 37%). The self-reported prevalence of HIV infection was similar to that found by oral fluid assay (2%). Many discrepancies were found between self-reported results and the results of oral fluid assays. Of those who reported being positive for HBV, HCV, or HIV, 48%, 5%, and 58%, respectively, tested negative on the oral fluid assay. Of those who reported a previous negative test result for HBV, HCV, or HIV, 10%, 37%, and 2%, respectively, had positive oral fluid assays. Self-reports of hepatitis and HIV infection status are unreliable and should not be used as a basis for planning preventive and treatment services for prisoners. All prisoners should have the opportunity to be tested for HBV, HCV, and HIV infection.

Antibodies, Viral↗
PubMed1997

National survey of MRSA: Ireland, 1995.

The objective of this survey was to obtain an indication of the size of the methicillin-resistant Staphylococcus aureus (MRSA) problem in Ireland prior to introducing national MRSA control guidelines. A survey of all microbiology laboratories in Ireland was carried out over two weeks in Spring 1995. For patients from whom MRSA was isolated during the study period standard demographic and clinical data were requested and period prevalence/1000 discharges was calculated. All 45 microbiology laboratories surveyed responded. MRSA was isolated from 448 patients during the two-week period. The period prevalence of MRSA was 16.5/1000 discharges. Males aged > or = 65 had the highest rate (50/1000 discharges). Half of all isolates were from patients in surgical or medical wards, but 4% were from community-based sources such as GPs, nursing homes and hospices. Thirty-two percent of MRSA patients were infected rather than colonized. MRSA is clearly a significant problem in Ireland. While it is largely a hospital problem at present, the increasing trend towards day procedures and shorter hospital stay means that infection will increase in the community.

Adolescent↗
PubMed1997

Ten-year survival of Down syndrome births.

OBJECTIVE: To determine the survival status of children with Down syndrome (DS), and to document factors influencing survival. DESIGN: Follow-up study of cases identified from the Dublin European Register of Congenital Anomalies and Twins (EUROCAT) Register. Follow-up was attempted for each case until death or 1992 or until the date last known to be alive. SETTING: Eastern Health Board, Dublin. SUBJECTS: In all, 389 DS children, born between 1 January 1980 and 31 December 1989 were followed up. RESULTS: Survival rates of 88% at one year and 82% at 10 years were found. There was a non-significant improvement in survival between the cohort born in 1980-1984 and that born in 1985-1989. Congenital heart defects reduced survival to 72% and complete atrio-ventricular canal defects (CAVD) had the poorest prognosis (58% survival at 10 years). Cases with CAVD showed a trend towards improved survival when surgically treated. Maternal age mother's county of residence, sex of infant, season of birth and presence of additional non-cardiac congenital anomalies had no impact on survival. CONCLUSIONS: Four out of five DS children now survive at least 10 years. Adequate educational and health service provision needs to be made for them, especially those with congenital heart defects. The need for studies which compare survival and quality of life in DS children with CAVD who undergo cardiac surgery versus those who do not, taking account of various selection factors, is identified.

Child↗
PubMed1996

Cryptosporidiosis in children who visited an open farm.

In the summer of 1995, cryptosporidiosis was diagnosed in a child in hospital. This child had taken part in a summer activity project involving 161 children and nine adults. Reports of a similar illness among a number of other participants prompted an outbreak investigation. A cohort study was conducted in two phases. Thirteen children (aged 6 to 15 years) out of 161 respondents to the first questionnaire met the case definition for illness and cryptosporidium was detected in stools from seven of the 13. Illness was significantly associated with child participants who had visited an open farm (p < .000005). Nine of the cases sought medical attention, and two were admitted to hospital. The second phase of the cohort study was conducted among 52 of the 55 people who had visited the open farm. Illness was significantly associated with playing in sand to which animals had access, at the edge of a stream beside a picnic area (p < .005). Contact with various animals was not associated with illness. This outbreak emphasises the risk for children of visiting open farms. Managers of open farms need to be aware of the potential for transmission of infectious diseases to visiting children. Strict implementation of hygiene measures is essential to minimise risk.

Adolescent↗
PubMed1996

Simultaneous multipolar radiofrequency ablation in the monopolar mode increases lesion size.

Delivery of radiofrequency (RF) energy from the distal tip of electrophysiology catheters produces lesions that may be too small to ablate arrhythmogenic sites during a single application of RF energy. To produce larger lesions, we delivered RF energy via a quadripolar catheter in which all four electrodes were connected in unipolar fashion. The catheter (Webster Labs) had a 4-mm tip, 2-mm ring electrodes, and 2-mm interelectrode distance. Lesion size was compared using RF energy delivered in a multipolar configuration with that delivered only to the distal tip using fresh bovine ventricular tissue. In vivo, RF lesions were made in dogs using the distal tip as well as all four poles of the same catheter inserted percutaneously. RF energy was delivered using a constant voltage at a frequency of 400 kHz. Preliminary experiments were conducted to determine the maximum power deliverable without coagulation using each electrode configuration. The use of simultaneous multipolar RF ablation produced significantly larger lesions both in vitro and in vivo. The length of the lesion was increased by a factor of approximately 2 in both the in vitro and in vivo experiments. There was a trend toward an increasing depth of the lesion by simultaneously applying RF energy to all four electrodes. Lesion width was significantly increased in the in vivo studies. We concluded that simultaneous multipolar delivery of RF energy produces larger lesions than can be obtained with delivery of RF energy to the distal tip alone. This technique may offer a means of increasing lesion size, leading to a decrease in the number of applications of RF energy necessary for ablation of arrhythmias.

Animals↗
PubMed1995

The risk of hepatitis A from sewage contamination of a water supply.

The drinking water supply of a town became contaminated with sewage. The town's population was surveyed to determine the baseline prevalence of hepatitis A antibodies and to establish whether an associated outbreak of hepatitis A had occurred. Samples of saliva were obtained from 540 people in 200 randomly selected households, and tested for IgG and IgM antibodies to hepatitis A. Fifty-six per cent (279/495) were susceptible to hepatitis A and 43% (213/495) immune as a result of previous infection. Immunity was directly related to age; those who were immune were significantly older than those who were susceptible (mean ages: 43.5 years and 19.0 years; p < 0.0001). Six people were found to have had a recent infection with hepatitis A, but exposure to hepatitis A during the water pollution incident was possible in only one case. The results offer no evidence that this incident caused an outbreak of hepatitis A, but the study has provided useful epidemiological data on hepatitis A.

Adolescent↗
PubMed1995

Illness in a community associated with an episode of water contamination with sewage.

Following an episode of water contamination with sewage in a rural Irish town, a community-wide survey of gastrointestinal-associated illness and health service utilization was conducted. Random sampling of households yielded residents who were surveyed using a self-administered questionnaire. Of 560 respondents from 167 (84%) households, equal proportions lived in areas known to have been exposed and unexposed to the contaminated water, although 65% of subjects reported using contaminated water. Sixty-one percent of subjects met the case definition. The most common symptoms among cases were abdominal cramps (80%), diarrhoea (75%), appetite loss (69%), nausea (68%) and tiredness (66%). Mean duration of illness was 7.4 days. Only 22% of cases attended their general practitioner. Drinking unboiled water from the exposed area was strongly associated with being a case. A substantial degree of community illness associated with exposure to contaminated water was observed. The episode ranks as one of the largest reported water-borne outbreaks causing gastrointestinal illness in recent times.

Disease Outbreaks↗