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Biomedical subjects

D O'Sullivan

Publications and source records attributed to D O'Sullivan.

At least 19 recordsLinked to original sources
PubMed2007

Mycosis fungoides--a review of the management of 28 patients and of the recent literature.

BACKGROUND: Mycosis fungoides is an uncommon cutaneous T-cell lymphoma characterized by malignant monoclonal proliferation of T-helper lymphocytes. Its course is variable with a potential for lymphatic and hematogenous involvement. We report the investigations, staging, treatment, follow-up, and outcome of 28 patients. This is the first such study reported from Ireland. METHODS: Twenty-eight patients with mycosis fungoides (14 women, 14 men; average age, 52.5 years) were reviewed over 12 years in the dermatology clinic which assesses an average of 4500 patients per year. All mycosis fungoides patients were referred from their family physicians. The diagnosis was made in all cases from a combination of clinical findings, histology, and immunohistochemistry. TNM staging revealed 11 patients at diagnosis stage IA (T1), 12 at stage IB (T2), four at stage IIB (T3), and one at stage III (T4). RESULTS: The usual male preponderance was not found. Eight patients needed multiple biopsies to establish the diagnosis. Detailed investigations were not useful in the early stages. Patients were followed up over a 12-year period. Thirteen patients died as a result of cutaneous lymphoma. Two patients with stage IA disease progressed rapidly and died, a feature reported in only 10% of patients at this stage. Five patients showed unusual features, including a long history prior to presentation, the development of the rarely reported bullous mycosis fungoides, and aggressive disease beginning at a young age. CONCLUSIONS: Mycosis fungoides is rare; we reviewed 28 patients over 12 years. The prognosis is poor at the later stages; 13 patients died. Two patients who died were unusual in that they rapidly progressed from stage IA disease; however, in the majority of patients with this stage, the prognosis is excellent. Detailed investigations were unhelpful in early stage disease. Close clinical follow-up is essential to identify disease progression.

Adult↗
PubMed2006

Comparative genomics of the lactic acid bacteria.

Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

Animals↗
PubMed2006

Radiation dosimetry for microbial experiments in the International Space Station using different etched track and luminescent detectors.

The laboratory of Microbiology at SCK.CEN, in collaboration with different universities, participates in several ESA programmes with bacterial experiments that are carried out in the International Space Station (ISS). The main objective of these programmes is to study the effects of space flight conditions such as microgravity and cosmic radiation on the general behaviour of model bacteria. To measure the radiation doses received by the bacteria, different detectors accompanied the microbiological experiments. The results obtained during two space flight missions are discussed. This dosimetry experiment was a collaboration between different institutes so that the doses could be estimated by different techniques. For measurement of the high linear energy transfer (LET) doses (>10 keV microm(-1)), two types of etched track detectors were used. The low LET part of the spectrum was measured by three types of thermoluminescent detectors ((7)LiF:Mg,Ti; (7)LiF:Mg,Cu,P; Al(2)O(3):C) and by the optically stimulated luminescence technique using Al(2)O(3):C detectors.

Cosmic Radiation↗
PubMed2004

Dose equivalent, absorbed dose and charge spectrum investigation in low Earth orbit.

Particle intensity, dose equivalent and absorbed dose have been measured on board the space shuttle Endeavour during STS-108 in December 2001 by Dublin Institute for Advanced Studies (DIAS). The dose estimates are based on very accurate measurements of recoils produced in CR-39 by cosmic ray primary and secondary protons and heavier nuclei and by secondary neutrons. The corresponding LET spectra were used to determine dose equivalent and absorbed dose values. Estimates of the total flux of Z > or = 2 nuclei have been undertaken and a preliminary charge spectrum was measured. Some comparisons are made with preliminary data obtained on STS-105 (ISS Expedition) and other missions using CR-39 detectors.

Cosmic Radiation↗
PubMed2004

Exposure of aircraft crew to cosmic radiation: on-board intercomparison of various dosemeters.

Owing to their professional activity, flight crews may receive a dose of some millisieverts within a year; airline passengers may also be concerned. The effective dose is to be estimated using various experimental and calculation tools. The European project DOSMAX (Dosimetry of Aircrew Exposure during Solar Maximum) was initiated in 2000 extending to 2004 to complete studies over the current solar cycle during the solar maximum phase. To compare various dosemeters in real conditions simultaneously in the same radiation field, an intercomparison was organised aboard a Paris-Tokyo round-trip flight. Both passive and active detectors were used. Good agreement was observed for instruments determining the different components of the radiation field; the mean ambient dose equivalent for the round trip was 129 +/- 10 microSv. The agreement of values obtained for the total dose obtained by measurements and by calculations is very satisfying.

Aircraft↗
PubMed2003

Cosmic ray measurements at aircraft altitudes and comparison with predictions of computer codes.

Extensive measurements of dose exposure of aircrew have been carried out in recent years using passive detectors on subsonic and supersonic air routes by DIAS (Dublin Institute for Advanced Studies). Studies were based on measurement of LET spectra using nuclear recoils produced in CR-39 nuclear track detectors by high energy neutrons and protons. The detectors were calibrated using energetic heavy ions. Data obtained were compared with the predictions of the EPCARD and CARI-6 codes. Good agreement has been found between the experimental and theoretical values.

Aircraft↗
PubMed2003

Tuberculosis and HIV seroprevalence in Lambeth, Southwark and Lewisham, an area of South London.

Since the mid-1980s the number of cases of TB notified within the U.K. has continued to rise although the contribution of HIV to this rise remains unclear. A 12-month prospective cohort study was conducted at chest and HIV clinics in four hospitals in Lambeth, Southwark and Lewisham (LSL), an area of South London, to determine the proportion of patients with culture-proven TB infected with HIV. Secondary aims were to determine the proportion of patients with TB and undiagnosed HIV at first presentation to chest clinics, to determine the proportion of patients presenting with TB as an AIDS defining illness (ADI) and to identify risk factors for co-infection with TB and HIV. In chest clinics, demographic data and left-over blood from patients aged 16 or over with culture-proven TB was collected, anonymised and HIV tested. In HIV clinics, demographic data on patients with TB already known to be HIV seropositive were also obtained. Twenty-one patients (13%, 95% CI-8-19%) of 159 with culture-proven TB were infected with HIV Four (3%) of 133 patients at first presentation to chest clinics had undiagnosed HIV; two were subsequently diagnosed. Of the 21 patients withTB and HIV, nine (43%) presented with TB as an ADI. Patients with TB and HIV were significantly more likely to be aged between 35 and 55 years compared to HIV seronegative patients [12/21 (57%) vs. 38/138 (28%), P=0.006]. None of the patients from the Indian Subcontinent were HIV seropositive [0/21 vs. 25/138 (18%), P=0.047]. At the present time, universal HIV testing of patients with culture-provenTB in chest clinics within the U.K. is unlikely to significantly reduce the number of patients with undiagnosed HIV.

AIDS-Related Opportunistic Infections↗
PubMed2002

Recent studies on the exposure of aircrew to cosmic and solar radiation.

Investigations of the impact of cosmic and solar radiation on aircrew involve many challenges. The great variety of primary and secondary ionising and non-ionising radiation, the wide range of energies involved and the role played by the Earth's atmosphere and magnetic field and the Sun combine to produce a very complicated scenario. These factors are reflected in conditions on aviation routes where exposure to radiation varies with altitude, latitude and stage of solar cycle. The great increase in air travel and consequent rise in numbers of aircrew whose occupation requires them to work in this environment has prompted new concern about exposure risks at aviation altitudes. The situation has also been highlighted by the tendency for aircraft to fly at higher altitudes in recent years and by the 1990 recommendations of the ICRP that exposure of civil aircrew be considered as being occupational. These have recently been translated into a legal requirement in the European Union. Several studies have been completed using a very wide range of detectors on subsonic and supersonic routes and new investigations are underway. With the completion of the DOSMAX project in another three years or so. world data for a whole solar cycle will be more complete than ever before. Results indicate that for most routes investigated during solar minimum, aircrew are unlikely to receive doses in excess of 6 mSv.y(-1).

Aerospace Medicine↗
PubMed2001

The cosmic ray actinide charge spectrum derived from a 10 m2 array of solid state nuclear track detectors in Earth orbit.

The DIAS-ESTEC Ultra Heavy Cosmic Ray Experiment (UHCRE) on the Long Duration Exposure Facility, collected approximately 3000 cosmic ray nuclei with Z > 65 in the energy region E > 1.5 GeV nucleon-1 during a six year exposure in Earth orbit. The entire accessible collecting area of the solid state nuclear track detector (SSNTD) array has been scanned for actinides, yielding a sample of 30 from an exposure of approximately 150 m2 sr yr. The UHCRE experimental setup is described and the observed charge spectrum presented. The current best value for the cosmic ray actinide relative abundance, (Z > 88)/(74 < or = Z < or = 87), is reported.

Actinoid Series Elements↗
PubMed2001

Investigation of cosmic rays and their secondaries at aircraft altitudes.

A very extensive study of the radiation field at aircraft altitudes has been carried out over the last few years. These investigations formed part of a European wide collaboration involving several laboratories with extensive experience in cosmic ray research and/or dosimetry. Among the main topics investigated were the charge spectra, LET spectra, anisotropy and dose values. The measurements were performed on subsonic and supersonic flights covering a wide range of altitudes and latitudes. Several active and passive instruments were employed in these studies and some results obtained with nuclear track detectors are described here. Comparisons are made with the results of other experiments and theoretical estimates using computer codes.

Aircraft↗
PubMed2001

The Italian national survey of aircrew exposure: I. Characterisation of advanced instrumentation.

The survey of aircrew exposure required the characterisation and/or the development of a diverse array of both passive and active instruments, which were not available at any one laboratory. To ensure the availability of the most advanced dosimetric systems and the relevant calibration facilities needed for the survey, an international collaboration was formed, which was facilitated by multinational research contracts promoted by the Commission of the European Communities. Close cooperation among scientists with long-term experience in different disciplines, such as cosmic ray measurement in space and radiation protection dosimetry, made it possible to exploit successfully damage track detectors for the accurate evaluation of very low fluences of particles with high energy and high charges. For a long time, the major concern for the assessment of aircrew exposure has been the accurate evaluation of the cosmic ray neutron dose. In this paper, four different dosimetric systems are considered, the response of which is sensitive to both low and high energy neutrons. All these dosimetric systems have provided consistent results when exposed together to the high energy beam facility at CERN, which is considered to approximate the cosmic ray field.

Aviation↗
PubMed2001

The Italian national survey of aircrew exposure: II. On-board measurements and results.

The Italian survey of aircrew exposure has been carried out with different advanced dosimetric systems, as described in part I of this paper. The key strategy of the survey was to obtain on-board comparison of measurements for both passive and real-time detectors flown together with passengers. The survey has been carried out in the period of solar minimum (1995-1997), in which the exposure to galactic cosmic rays reaches its maximum value. Even though carrying out the survey in the period of solar minimum was entirely coincidental, this circumstance has been used to good advantage to obtain a comprehensive set of data of the galactic cosmic radiation with little or no disturbance by the solar activity modulation. This comprehensive set of data covers flight routes between -20 degrees and 75 degrees geographic latitude at different civil aviation altitudes. The survey obtained with different advanced dosimetric systems has been supplemented by a large variety of data gathered with passive stacks on different short-range and long-range flights at supersonic and subsonic altitudes. Some of the most important conclusions which can be drawn from the survey are: (i) aircrew of civil aviation receive annual doses within the range of 1 mSv to 6 mSv; (ii) data from different periods of solar minimum agree well, since the discrepancies encountered seem mainly due to the different dosimetric systems used; (iii) repeated measurements on the same route are highly consistent.

Aircraft↗
PubMed2001

Cyclosporin for atopic dermatitis in children.

This paper details a UK consensus conference held in London in April 2000 to establish guidelines for the use of cyclosporin A for atopic dermatitis in children. It should be reserved for the severest refractory atopic dermatitis. In view of its potential toxicity, careful monitoring is mandatory, in particular blood pressure and renal function.

Child↗
PubMed2001

Double-J ureteral stents: an alternative to external urinary stents in orthotopic bladder substitution.

OBJECTIVE: The aim of this study was to compare advantages and disadvantages of using double-J or external stents to preserve the uretero-ileal anastomosis in patients receiving an orthotopic neobladder. METHODS: 77 consecutive patients with bladder cancer who underwent radical cystoprostatectomy and Studer neobladder were evaluated. All patients received a direct spatulated end-to-side uretero-ileal anastomosis in the afferent loop (Nesbit technique). In 45 patients (group A), the stents (Bracci ureteral splint) were brought our through the reservoir and anchored to the skin; in 32 patients (group B), an internal double-J stent was used. Median follow-up was 30 months. RESULTS: 9 (11.5%) uretero-ileal anastomosis strictures in group A and 7 (11.6%) in group B were observed. There was a significant difference in the side of stricture with a greater prevalence on the left side (p<0.004). Stricture formation and side were not related to the type of stent used. 14 (20%) neobladder-ureteral refluxes occurred, with a non-significant difference between the two groups (p = 0.37). 12 patients (86%) were asymptomatic; two patients developed pyelonephritis and needed antibiotic treatment. Neobladder catheter was removed after 17 days (range: 15-18 days) and 14 days (range: 12-15 days), respectively, in group A and group B with an earlier discharge of the patients in group B. There was a significant difference in mean hospital stay between the two groups (Mann-Whitney test p<0.0001). Discomfort related to the stent was mild for most of the patients of group B (84%). CONCLUSIONS: Internal stenting is an equally effective alternative to external stent in patients undergoing bladder replacement. The use of double-j stents appears to be associated with minimal discomfort, earlier mobilization and a shorter hospital stay.

Aged↗
PubMed2000

Novel type I restriction specificities through domain shuffling of HsdS subunits in Lactococcus lactis.

This study identifies a natural system in Lactococcus lactis, in which a restriction modification specificity subunit resident on a 6159 bp plasmid (pAH33) alters the specificity of a functional R/M mechanism encoded by a 20.3 kb plasmid, pAH82. The new specificity was identified after phenotypic and molecular analysis of a 26.5 kb co-integrate plasmid (pAH90), which was detected after bacteriophage challenge of the parent strain. Analysis of the regions involved in the co-integration revealed that two novel hybrid hsdS genes had been formed during the co-integration event. The HsdS chimeras had interchanged the C- and N-terminal variable domains of the parent subunits, generating two new restriction specificities. Comparison of the parent hsdS genes with other type I specificity determinants revealed that the region of the hsdS genes responsible for the co-integration event is highly conserved among lactococcal type I hsdS determinants. Thus, as hsdS determinants are widespread in the genus Lactococcus, new restriction specificities may evolve rapidly after homologous recombination between these genes. This study demonstrates that, similar to previous observations in Gram-negative bacteria, a Gram-positive bacterium can acquire novel restriction specificities naturally through domain shuffling of resident HsdS subunits.

Amino Acid Sequence↗
PubMed2000

European measurements of aircraft crew exposure to cosmic radiation.

For more than 5 y, the European Commission has supported research into scientific and technical aspects of cosmic-ray dosimetry at flight altitudes in civil radiation. This has been in response to legislation to regard exposure of aircraft crew as occupational, following the recommendations of the International Commission on Radiological Protection in Publication 60. The response to increased public interest and concern, and in anticipation of European and national current work, within a total of three multi-national, multi-partner research contracts, is based on a comprehensive approach including measurements with dosimetric and spectrometric instruments during flights, at high-mountain altitudes, and in a high-energy radiation reference field at CERN, as well as cosmic-ray transport calculations. The work involves scientists in the fields of neutron physics, cosmic-ray physics, and general dosimetry. A detailed set of measurements has been obtained by employing a wide range of detectors on several routes, both on subsonic and supersonic aircraft. Many of the measurements were made simultaneously by several instruments allowing the intercomparison of results. This paper presents a brief overview of results obtained. It demonstrates that the knowledge about radiation fields and on exposure data has been substantially consolidated and that the available data provide an adequate basis for dose assessments of aircraft crew, which will be legally required in the European Union after 13 May 2000.

Aircraft↗