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Biomedical subjects

J Malone

Publications and source records attributed to J Malone.

At least 19 recordsLinked to original sources
PubMed2006

Subjective and objective measures of image quality in digital fluoroscopy.

There are numerous methods for assessing image quality in diagnostic X ray. In our study we assessed how imaging quality assurance methods perform in practice. Physics assessments were based on IPEM protocols using Leeds test objects. Clinical assessment was based on a questionnaire. A total of 15 systems in three European locations were assessed, covering a range of image intensifier-TV digital fluoroscopy units. Analysis of 274 clinical questionnaires showed that clinical and physics assessments did not place systems in the same order, based on a given image quality parameter. In almost all the comparisons, low level correlation was measured for statistical comparison of rank order (rs < 0.3). However, broad agreement was observed between physics and clinical assessments for image quality associated with contrast and noise. This study emphasises the importance of maintaining links with clinical assessment, when developing quality assurance metrics, and measuring the mutual performance of clinical and physical assessments of image quality.

Europe↗
PubMed2006

Equipment standards for interventional cardiology.

Interventional radiology has seen rapid growth in cardiology and represents an alternative to hazardous surgery. Recently there has been a substantial growth in the number of procedures being performed and interventional cardiology (IC) procedures are the most common interventional procedures in Europe. Advances in imaging technology have facilitated the development of increasingly complex radiological IC equipment. Currently, the technology is developing at a rate ahead of supporting research, equipment standards and a regulatory framework. International standards play a key role in the design, manufacture and performance of radiological IC equipment. A survey of 12 IC systems (15 imaging chains) was conducted in Irish hospitals. The aim of the study was to assess the imbalance between rapidly advancing technology and existing standards and to propose recommendations for new IC equipment standards. The results demonstrate the need for definitive equipment requirements and standardisation in the design, manufacture, acceptance and maintenance of IC equipment.

Cardiology↗
PubMed2004

Q fever in Ireland. A seroprevalence study of exposure to Coxiella burnettii among Department of Agriculture workers.

OBJECTIVES: To estimate the risk of exposure to Coxiella burnettii among 'at risk' workers in Ireland. METHODS: A cross-sectional seroprevalence study, using the complement fixation technique (CFT), was carried out among technical and support staff of the Department of Agriculture in Ireland (n = 375). Participants were divided into low- (n = 34), moderate- (n = 158) and high-risk (n = 83) groups according to the likelihood of occupational exposure. A result of <1:8 on CFT was accepted as normal, i.e. no evidence of past exposure to the causative organism, C. burnettii. Participants with titres of 1:16 were clinically assessed for evidence of past or present infection and interviewed regarding the possibility of non-occupational exposure. RESULTS: The participation rate was 75% (n = 281). Overall, 24 of the 281 participants (8.5%, 95% confidence interval = 5.6-12.4%) tested positive (titres = 1:8). No statistically significant difference existed between the three groups (low, 8.8%; moderate, 9.5%; high, 7.2%). Of those reviewed (n = 10), no evidence of either past or present clinically significant illness was detected. Possible non-occupational exposure was identified in two cases. CONCLUSION: Laboratory evidence of past exposure to Q fever is common amongst readily identifiable 'at risk' occupational groups in Ireland, and appropriate preventative steps are warranted. Employees who do not have direct exposure to animals or animal products, but who work in a high risk environment appear to have a similar risk of exposure C. burnettii. Although clinical illness appears to be rare, health care workers should consider the possibility of Q fever in cases of unexplained illness arising in those working in 'high risk' environments.

Agricultural Workers' Diseases↗
PubMed2003

A cross-sectional study of employer and employee occupational health needs and priorities within the Irish Civil Service.

BACKGROUND: This study aimed to establish how important an occupational health unit (OHU) is to its clients, and to identify the perceived needs and priorities for such a service. METHODS: A cross-sectional postal survey of a stratified, randomly selected group of employees (n = 760) and all human resources (HR) managers (n = 34) was conducted in the Irish Civil Service. Each participant was requested to rate the overall importance of the OHU and to prioritize eight proposed functions for the unit: medical surveillance, general health education, pre-employment/promotion medical assessments, ill-health retirement assessments, return-to-work (after sick leave) assessments, occupational health education, research, and general medical screening. The results were analysed according to age group, gender, grade and occupation. RESULTS: There was a response rate of 69% from employees and 74% from personnel managers. Significantly more HR managers than employees (92 versus 81%) thought an occupational health service was either important or very important. There were also differences in prioritization of functions by employees and HR managers. HR managers prioritized those functions concerned with assessing individuals' fitness for work, notably pre-employment/promotional health assessments, whereas employees consider group-directed 'preventative' functions to be more important, i.e. general medical screening, health education and medical surveillance. Both sets of opinions are not mutually exclusive, and considerable overlap exists, notably in the areas of occupational and general health education.

Adult↗
PubMed2003

[Establishment of minimum medical geographic information systems database in China].

OBJECTIVE: To establish a minimum medical geographic information systems (GIS) database as a spatial decision supporting system (SDSS), and to use the database into public health practice in China. METHODS: Spatial data collected from different sources were standardized as decimal degree format, including: (1) satellite images covering areas of China; (2) digital maps of China in vector files; (3) diseases database and relevant models. RESULTS: Necessary satellite images for the database have been collected from NOAA AVHRR, Landsat TM, etc., including the normalized difference vegetation index (NDVI) images from AVHRR, earth surface temperature images from AVHRR, GTOPO30 DEM images from USGS and landuse images from USGS. The digital vector files for GIS analysis were collected including political (county, provinces, country) boundaries file, environmental (drainage, land cover, soil type) vector file, population data and climate data; Data on diseases mainly generated from survey or case reporting. Relevant models on transmission of Schistosoma japonicum and Plasmodium vivax, and models of Oncomelania hupensis and Anophores sinansis were developed, and the relevant environmental factors related to incidence of cancers were mapped, to test and verify those database. CONCLUSION: The database unified the data from different sources for users. Minimum medical data included in the database could be used in the practice of public health. It is expected that this database be used in a wider range.

Animals↗
PubMed2001

Recombinant human antibody single chain variable fragments reactive with Candida albicans surface antigens.

A combinatorial phage display library expressing human immunoglobulin heavy and light chain variable regions was used to identify phage clones capable of binding to the surface of Candida albicans blastoconidia. Single chain antibody variable fragments (scFv) derived from three clones detected C. albicans antigens by indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and Western blotting. The antigens detected were conserved among different strains of C. albicans and several other Candida species. Two scFv clones detected antigens specifically expressed by C. albicans blastoconidia; the third detected antigens in both blastoconidia and filamentous forms of C. albicans. The antigens containing the epitopes recognized by all three scFv could be extracted from blastoconidia by dithiothreitol, suggesting attachment to the cell wall via sulfhydryl bonds. Epitope detection by the scFv was sensitive to treatment of C. albicans blastoconidia with sodium periodate, but not proteinase K, indicating the cognate epitopes were composed of carbohydrate. Antigenic determinants for each of the three scFv were detected by immunohistochemical staining of skin sections from a model of cutaneous candidiasis, demonstrating expression in vivo. Through selection for the ability to bind intact organisms, the phage display system provides a means to rapidly identify monoclonal binding ligands to Candida surface antigens. Being entirely human, mature antibodies generated from the scFv have potential utility in the treatment of candidiasis.

Amino Acid Sequence↗
PubMed2001

Effective dose in Albanian direct chest fluoroscopy.

In the absence of reliable supplies of X-ray film, direct fluoroscopy is still extensively used in Albania, with chest radiology a particularly common application. This paper aims to quantify both patient skin dose and the risk-related quantity effective dose for direct fluoroscopy units based in seven different Albanian X-ray departments. A standard Quality Assurance (QA) protocol was used to assess tube potential accuracy, half value layer and X-ray tube output of these units. Three groups of X-ray beam parameters were defined from the QA results, covering the range of chest posteroanterior (PA) fluoroscopy technique factors seen during the study. Organ-equivalent doses were then measured for a nominal PA chest fluoroscopy examination using a Rando anthropomorphic phantom loaded with lithium fluoride thermoluminescent dosimeter chips. Normalised organ dose factors are listed for the three groups of beam conditions simulated. Using these factors, effective dose for the seven systems surveyed was found to be between 0.06 and 0.42 mSv for a 20 s PA chest fluoroscopy examination. Mean effective dose for this group of systems was 0.22 mSv which is a factor of 13 greater than mean effective dose for film/screen PA chest radiography in the UK, whereas entrance surface dose was a factor of 50 greater than the current EU reference level.

Albania↗
PubMed2001

Beneficial effects of intensive therapy of diabetes during adolescence: outcomes after the conclusion of the Diabetes Control and Complications Trial (DCCT).

OBJECTIVE: The Diabetes Control and Complications Trial (DCCT) demonstrated that intensive therapy of type 1 diabetes mellitus reduces the risk of development and progression of microvascular complications. The Epidemiology of Diabetes Interventions and Complications (EDIC) study assessed whether these benefits persisted after the end of DCCT. Results for the adolescent DCCT cohort are reported here. STUDY DESIGN: Of the DCCT adolescent cohort (n = 195), 175 participated in EDIC, 151 had fundus photography, and 156 had albumin excretion rate measured at year 3 or 4. The odds of progression of retinopathy and albuminuria from closeout of the DCCT until EDIC year 4 were assessed. RESULTS: In contrast to the 7.4 years of the DCCT, during which mean hemoglobin A(1c) levels were significantly lower with intensive therapy than conventional therapy (8.06% vs 9.76%; P <.0001), the subsequent first 4 years of EDIC had mean hemoglobin A(1c) levels that were similar between the former intensive and the former conventional groups (8.38% vs 8.45%). However, the prevalence of worsening of 3 steps or more in retinopathy and of progression to proliferative or severe nonproliferative retinopathy were reduced by 74% (P <.001) and 78% (P <.007), respectively, in the former intensive therapy group compared with the former conventional group. CONCLUSIONS: These findings provide further support for the DCCT recommendation that most adolescents with type 1 diabetes receive intensive therapy aimed at achieving glycemic control as close to normal as possible to reduce the risk of microvascular complications.

Adolescent↗
PubMed2001

A critical overview of acceptance testing using various measured indices.

It is a requirement of the new European directive on health protection of individuals against the dangers of ionising radiation in relation to medical exposure (97/43/EURATOM), that acceptance testing is carried out on all radiological equipment before its first use for clinical purposes. This directive must be implemented into member state law. In accordance with this requirement, thirteen digital fluorography systems were acceptance tested by the Department of Medical Physics and Bioengineering, St James's Hospital, Dublin. The equipment tested was in six Irish hospitals and included nine systems intended for interventional use, two of which were dedicated cardiac catheterisation laboratories and two of which were dedicated vascular laboratories. Testing was performed in line with current published international guidelines and standards and involved the measurement and analysis of various indices including X ray tube and generator performance, operating dose levels, image quality and electrical, mechanical and radiation safety aspects. The results are presented and compared with international standards and recommendations. Problems were identified with all systems tested with approximately 70% of all systems demonstrating significant problems. This study emphasises the importance of acceptance testing radiological equipment.

European Union↗
PubMed2001

Quality criteria for cardiac images in diagnostic and interventional cardiology.

The quality of cardiac imaging plays a pivotal role in clinical decision-making and depends mainly on the technical performance of the imaging system and on angiographic technique. The Italian Society of Invasive Cardiology and The Italian Society of Physics in Medicine have set quality criteria giving precise guidelines regarding how an angiogram should appear provided that good equipment and correct angiographic technique are used. The criteria have been reviewed by the European Concerted Action DIMOND Cardiology group and are reported here to provide a reference standard for images for the most common procedures in daily practice.

Angioplasty, Balloon, Coronary↗
PubMed2000

Coxsackievirus expression of the murine secretory protein interleukin-4 induces increased synthesis of immunoglobulin G1 in mice.

We cloned the sequence encoding murine interleukin-4 (mIL-4), including the secretory signal, into the genome of CVB3/0, an artificially attenuated strain of coxsackievirus B3, at the junction of the capsid protein 1D and the viral protease 2Apro. Two strains of chimeric CVB3 were constructed using, in one case, identical sequences to encode 2Apro cleavage sites (CVB3/0-mIL4/47) on either side of the inserted coding sequence and, in the other case, nonidentical sequences that varied at the nucleotide level without changing the amino acid sequences (CVB3-PL2-mIL4/46). Transfection of HeLa cells yielded progeny viruses that replicated with rates similar to that of the parental CVB3/0 strain, although yields of mIL-4-expressing strains were approximately 10-fold lower than those of the parental virus. Western blot analysis of viral proteins isolated from HeLa cells inoculated with either strain of chimeric virus demonstrated that the chimeric viruses synthesized capsid protein 1D at approximately twofold-higher levels than the parental virus. mIL-4 protein was detected by enzyme-linked immunosorbent assay (ELISA) in HeLa cells inoculated with either strain of chimeric virus. Lysates of HeLa cells inoculated with either chimeric virus induced the proliferation of the mIL-4-requiring murine MC-9 cell line, demonstrating biological activity of the CVB3-expressed mIL-4. Reverse transcription (RT)-PCR analysis of viral RNA derived from sequential passaging of CVB3/0-mIL4/47 in HeLa cells demonstrated deletion of the mIL-4 coding sequence occurring by the fourth passage, while similar analysis of CVB3-PL2-mIL4/46 RNA demonstrated detection of the mIL-4 coding sequence in the virus population through 10 generations in HeLa cells. mIL-4 protein levels determined by ELISA were consistent with the stability and loss data determined by RT-PCR analysis of the passaged viral genomes. Studies of insert stability of CVB3-PL2-mIL4/46 during replication in mice showed the presence of the viral mIL-4 insert in pancreas, heart, and liver at 14 days postinfection. Comparison of the murine antibody responses to CVB3-PL2-mIL4/46 and the parental CVB3/0 strain demonstrated an increased level of CVB3-binding serum immunoglobulin G1 in mice inoculated with CVB3-PL2-mIL4/46.

Amino Acid Sequence↗
PubMed2000

Ocular microtremor (OMT): a new neurophysiological approach to multiple sclerosis.

Using a piezoelectric transducer, the frequency and pattern of ocular microtremor (OMT) between 50 normal subjects and 50 patients with multiple sclerosis were compared. Controls were age matched. All records were analysed blindly. The frequency of OMT in the normal group was 86 (SD 6) Hz, which was significantly different from that of the multiple sclerosis group (71 (SD) 10 Hz, p<0.001). Those in the multiple sclerosis group with clinical evidence of brain stem or cerebellar disease (n=36) had an average OMT frequency of 67 (SD 9) Hz (p<0.001) compared with normal (n=86), whereas those with no evidence of brain stem or cerebellar involvement (n=14) had a frequency of 81.2 (SD 6) Hz (p<0.05, n=64). The differences between the two multiple sclerosis groups were also significant (p<0. 001, n=50). At least one abnormality (frequency and pattern) of OMT activity was seen in 78% of patients with multiple sclerosis. In the presence of brain stem or cerebellar disease 89% had abnormal records whereas in the absence of such disease 50% had abnormal records. This is the first report of the application of this technique to patients with multiple sclerosis. The results suggest that OMT activity may be of value in the assessment of multiple sclerosis.

Adult↗
PubMed1999

Assembly of the type 1 procollagen molecule: selectivity of the interactions between the alpha 1(I)- and alpha 2(I)-carboxyl propeptides.

Assembly of the heterotrimeric procollagen I molecule is initiated by interactions between the carboxyl propeptide domains of the completed nascent pro alpha chains. The [pro alpha 1(I)]2[pro alpha 2(I)] heterotrimer is the predominant molecule, with much smaller amounts of stable [pro alpha 1(I)]3 homotrimer also being formed. However, the [pro alpha 2(1)]3 homotrimer has not been detected, raising questions as to the mechanism of chain assembly and why [pro alpha2(1)]3 homotrimers are not formed. These questions have been examined here by expressing the intact and amino- or carboxyl-terminal truncated C-propeptides of the pro alpha chains recombinantly in bacteria and in a coupled transcription/translation reticulocyte lysate system. Their interactions were studied in vitro by binding analyses and in vivo by using the yeast two-hybrid system. The C-pro alpha 1(I) interacted with itself, and with C-pro alpha 2(I), as expected. Surprisingly, the C-pro alpha 2(I) also interacted with itself, both in vitro and in vivo. While the interaction of C-pro alpha 2(I) with itself and C-pro alpha 1(I) in vitro was strong, these interactions were weaker in vivo. Deletion of 36 amino acids from the C-terminal domain of C-pro alpha 1 had no effect on its binding to intact self or intact C-pro alpha 2, but the same deletion in C-pro alpha 2 completely abolished its binding to intact C-pro alpha 2 and to C-pro alpha 1. Comparable N-terminal deletions in C-pro alpha 1 or C-pro alpha 2 diminished, but did not abolish, their binding to intact C-pro alpha 1 and C-pro alpha 2. In the yeast two-hybrid system, C-pro alpha 2 interacted with itself more weakly than with C-pro alpha 1. Molecular modeling and circular dichroism analyses showed that C-pro alpha 1 and C-pro alpha 2 have different folded structures and stability. Studies with antibodies specific to the C-pro alpha1 and alpha2 peptides showed them to precipitate different, specific, and distinct cell proteins from fibroblast lysates. The C-pro alpha 2(I) antibody complexed with more cell proteins. We hypothesize that the lack of pro alpha 2(I) homotrimers is not due to the inability of the C-pro alpha 2(I) to interact with itself, but rather to the competing presence of other cell proteins. The specificity of these interactions may reside in conformational differences in N- and C-terminal sequences of the two propeptides or in their different folding patterns.

Amino Acid Sequence↗
PubMed1999

Only multiple autoantibodies to islet cells (ICA), insulin, GAD65, IA-2 and IA-2beta predict immune-mediated (Type 1) diabetes in relatives.

We report here our prospective study of 15,224 non-diabetic, first-degree relatives of probands with immune-mediated (type 1) diabetes (IMD), of which 135 were found to eventually develop diabetes. We determined islet cell, insulin, GAD65, insulinoma-associated antigen-2 and 2beta autoantibodies (ICA, IAA, GAD65A, IA-2A and IA-2betaA), on the first available serum samples. The latter three autoantibodies were however assayed on subsets of the relatives with and without ICA, IAA and/or GAD65A, plus most of the relatives who developed diabetes. Of the relatives who progressed to diabetes, 94% had at least one of these autoantibodies on the first screening, while ICA proved to be the most sensitive single marker (sensitivity 74%). Risk of diabetes was however negligible when ICA was found in the absence of the others (5-year risk=5.3%), but increased dramatically whenever two or more autoantibodies were present (5-year risk=28.2% and 66.2%, respectively). The most predictive combination of markers was ICA plus IA-2A and/or IA-2beta A. Loss of first phase insulin release to IVGTT also occurred only in those ICA-positive relatives who had one or more of the other autoantibodies. The data suggests that significant beta-cell damage is seen only when the underlying autoimmunity has spread to multiple antigenic islet cell determinants. Combinations of the autoantibodies occurred most often in relatives with the highest risk HLA-DR/DQ phenotypes. These data document that only relatives positive for at least two or more of these five autoantibodies are at significant risk of diabetes themselves. Intervention trials for the prevention of type 1 diabetes could be designed based on testing for these autoantibodies alone, without the need for HLA typing and IVGTT testing.

Adolescent↗