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A Peeters

Publications and source records attributed to A Peeters.

At least 19 recordsLinked to original sources
PubMed2003

Hirshfeld partitioning of the electron density: atomic dipoles and their relation with functional group properties.

Atomic dipole moments, derived within the Hirshfeld partitioning of the molecular electron density, have been studied for compounds of the type H-X and Cl-X, for a series of functional groups X frequently encountered in organic molecules. In the case of the H-X compounds, the component of the atomic dipole moment on H along the axis connecting H with the central atom in X is found to be linearly correlated with the electronegativity of X, the hardness of X playing no significant role. In the case of the Cl-X compounds, the situation is less clear. However, evidence seems to point to the conclusion that for these compounds, also the group hardness plays an important role.

Journal Article↗
PubMed2002

Atomic charges, dipole moments, and Fukui functions using the Hirshfeld partitioning of the electron density.

In the Hirshfeld partitioning of the electron density, the molecular electron density is decomposed in atomic contributions, proportional to the weight of the isolated atom density in the promolecule density, constructed by superimposing the isolated atom electron densities placed on the positions the atoms have in the molecule. A maximal conservation of the information of the isolated atoms in the atoms-in-molecules is thereby secured. Atomic charges, atomic dipole moments, and Fukui functions resulting from the Hirshfeld partitioning of the electron density are computed for a large series of molecules. In a representative set of organic and hypervalent molecules, they are compared with other commonly used population analysis methods. The expected bond polarities are recovered, but the charges are much smaller compared to other methods. Condensed Fukui functions for a large number of molecules, undergoing an electrophilic or a nucleophilic attack, are computed and compared with the HOMO and LUMO densities, integrated over the Hirshfeld atoms in molecules.

Journal Article↗
PubMed2002

Poor voice quality in future elite vocal performers and professional voice users.

The voice quality of 86 occupational voice users, i.e., students of a high school for audiovisual communication, was assessed by means of a multidimensional test battery containing: the GRBAS scale, videolaryngostroboscopy, maximum phonation time, jitter, lowest intensity, highest frequency, dysphonia severity index (DSI), and voice handicap index (VHI). In a questionnaire on daily habits the prevalence of smoking, eating habits, and vocal abuse were recorded. A comparison of the voice characteristics of the future occupational voice users with a control group revealed significant differences. The results of the VHI and the DSI of these students revealed significantly worse scores than the score of a control group characterized by no vocal complaints. Moreover, the questionnaire on daily habits showed that the future elite vocal performers and professional voice users take less precautions for the care of their voices. These findings support the importance of a good balanced vocal coaching.

Adolescent↗
PubMed2002

A cardiovascular life history. A life course analysis of the original Framingham Heart Study cohort.

AIMS The objective of this paper is to measure the potential burden of cardiovascular disease within the original Framingham Heart Study cohort by transforming its well-described epidemiological measures into time-based health policy measures, such as life years lost to or lived with the disease. METHODS AND RESULTS We constructed multi-state life tables of the Framingham Heart Study cohort to calculate dwelling times with a history of cardiovascular disease. Age-specific probabilities determined transitions from healthy through disease to death. For this synthetic cohort, from age 50 men (women) live on average 26 (32) years; 20 (26) free of cardiovascular disease. Allowing occupancy of more than one disease state, 50-year-old males (females) live 2 X 9 (1 X 2) years with a history of myocardial infarction, 0 X 93 (1 X 2) with a history of stroke, and 0 X 67 (0 X 93) with congestive heart failure. Having ever suffered acute myocardial infarction, stroke or congestive heart failure, life expectancy is reduced by 9 (13), 12 (15) or 16 (16) years, respectively in 60-year-old men (women). CONCLUSIONS Transforming occurrence probabilities into time-based health measures, the prevalence of cardiovascular disease is remarkable: from age 50, 20% of remaining life expectancy is lived with the disease. Such measures are integral to appropriate health planning and assessment of the potential population health value of various treatment and prevention strategies.

Adult↗
PubMed2001

Cost-effectiveness of prescribing statins according to pharmaceutical benefits scheme criteria.

OBJECTIVES: (i) To analyse how well Pharmaceutical Benefits Scheme (PBS) criteria for prescribing lipid-lowering therapy identify people most at risk of coronary heart disease (CHD); and (ii) to determine the cost-effectiveness of primary prevention therapy with pravastatin according to these criteria in Australia. DESIGN: (i) Analysis of targeting of CHD risk according to PBS criteria; (ii) cost-effectiveness analysis for pravastatin as primary preventive therapy (40 mg/day), with a 20-year projection from 1999. PARTICIPANTS: (i) Men and women aged 25-69 years from the 1989 National Heart Foundation Risk Factor Prevalence Survey; (ii) Australian men and women, aged 25-85 years, excluding those with diabetes and existing CHD. MAIN OUTCOME MEASURES: (i) Proportion eligible for lipid lowering treatment according to PBS criteria within 15-year risk of CHD mortality groups; (ii) average net cost in Australian dollars ($) per year of life saved (YOLS), with 80% uncertainty ranges (UR). RESULTS: (i) PBS criteria do not adequately identify those most at risk of CHD, as only 61% of Australians (aged 25-69 years) with a greater than 10% 15-year risk of CHD mortality were eligible for treatment; and 11% of those at low risk of CHD mortality (< 2.5% over 15 years) were eligible for treatment. (ii) Cost-effectiveness of treatment according to PBS criteria was estimated at $110,000 (80% UR, $96,000-$150,000) per YOLS for men and $87,000 (80% UR, $80,000-$130,000) per YOLS for women. As an indicator of the likely recurrent annual costs, total first-year treatment costs (excluding the costs of non-compliers) were estimated at $940 million. Assuming compliance of 50%, cost-effectiveness of treatment was markedly improved using 32.5% 15-year risk of CHD mortality as a cut-off, with ratios of $31,000 (80% UR, $27,000-$40,000) per YOLS for men and $39,000 (80% UR, $33,000-$53,000) per YOLS for women. First-year treatment costs of $940 million were the same as treating according to PBS criteria, but absolute health impact in terms of deaths averted and years of life saved was more than doubled. CONCLUSIONS: While PBS criteria do target patients at risk of CHD, there is room for improvement in identifying those most at risk of CHD, and treatment according to PBS criteria is not likely to be the most cost-effective. For optimal cost-effectiveness, targeting of therapy for primary CHD prevention needs to be based on population-specific, multivariable risk.

Adult↗
PubMed2001

PBS/RPBS cost implications of trends and guideline recommendations in the pharmacological management of hypertension in Australia, 1994-1998.

OBJECTIVES: To determine the extent to which "current guidelines" for the management of hypertension are reflected in the prescribing of antihypertensive drugs in Australia over the period 1994-1998, and to examine the cost implications of actual and recommended prescribing patterns. DESIGN: Federal Government and consumer cost estimates modelled on prescribing patterns and guideline recommendations over the period 1994-1998. SETTING: Prescribing on Federal Government pharmaceutical schemes over the 1994-1998 period. MAIN OUTCOME MEASURES: Estimates of Pharmaceutical Benefits Scheme/Repatriation Pharmaceutical Benefits Scheme cost changes in Australian dollar values. RESULTS: The implementation of current guidelines for patients with uncomplicated hypertension taking monotherapy alone could have reduced drug costs by $45-$108 million in 1998. CONCLUSIONS: Current prescribing patterns indicate that clinical practice has pre-empted the results from clinical trials of newer, more expensive agents and that clinicians' prescribing patterns do not closely reflect current recommendations.

Antihypertensive Agents↗
PubMed2001

Dextran reduces embolic signals after carotid endarterectomy.

One hundred fifty patients undergoing carotid endarterectomy were randomly assigned to receive intravenous 10% dextran 40 or placebo. Transcranial Doppler monitoring of the ipsilateral middle cerebral artery 0 to 1 hour postoperatively detected embolic signals in 57% of placebo and 42% of dextran patients, with overall embolic signal counts 46% less for dextran (p = 0.052). Two to 3 hours postoperatively, embolic signals were present in 45% of placebo and 27% of dextran patients, with embolic signal counts 64% less for dextran (p = 0.040). We conclude that dextran reduces embolic signals within 3 hours of CEA.

Aged↗
PubMed2001

Results from the first 12 months of a fire first-responder program in Australia.

STUDY OBJECTIVE: We aimed to reduce response times and time to defibrillation for out-of-hospital cardiac arrest patients through fire first-responders equipped with automatic external defibrillators (AEDs). The fire first-responders were added as an extra tier to the existing two-tired ambulance response. METHODS: This prospective controlled trial set in Melbourne, Australia, consisted of a control area (277 km2, population density 2343/km2-ambulance only dispatch) and a pilot area (171 km2, population density 2290/km2-ambulance and fire first-responder dispatch). The main outcome measures were time to emergency medical service (EMS) arrival at scene for all cardiac arrest patients and time to defibrillation for cardiac arrest patients presenting in ventricular fibrillation (VF). The study participants were patients who suffered a cardiac arrest of presumed cardiac aetiology for which a priority 0 emergency response was activated. A total of 268 patients were located in the control area and 161 in the pilot (intervention) area. RESULTS: The mean response time to arrival at scene was reduced by 1.60 (95% CI 1.21, 1.99) min, P < 0.001. A large reduction in prolonged responses (> or = 10 min) to cardiac arrests was also observed in the pilot area (2%) compared with the control area (18%), chi = 23.19, P < 0.001. Mean time to defibrillation was reduced by 1.43 (95% CI 0.11, 2.98) min, P = 0.068. CONCLUSION: The results from this study suggest that fire officers can be successfully trained in the use of AEDs and can integrate well into a medical response role. The combined response of ambulance and fire personnel significantly reduced the response interval and reduced time to defibrillation. This suggests that in appropriate situations other agencies could be considered for involvement in co-ordinated first-responder programs.

Australia↗
PubMed2001

Predicted impact on Victoria's ambulance services of a new major trauma system.

BACKGROUND: In 1999, a new major trauma system was proposed for the state of Victoria, Australia. The guidelines for the new system were aimed at delivering major trauma cases to definitive trauma care in the least time possible. The aim of the present study was to analyse the potential effect of this system on Victoria's ambulance services. METHODS: The present study modelled the workload of major trauma cases in Victoria's ambulance service for one year pre- and post-introduction of the guidelines. Cases were analysed regarding whether their first hospital destination would change under the proposed guidelines, and, subsequently, whether they would require interhospital transport to a higher level trauma service. The impact on the ambulance services was modelled as annual changes in distances travelled due to predicted changes in hospital destinations. RESULTS: Analysis of the predicted changes indicated that, in general, Victoria's metropolitan and rural road ambulance crews would not be greatly affected. However, some metropolitan road crews may have to travel extra distances for up to 110 cases per year. The major impact was on air retrieval crews, where the annual number of interhospital transfers is predicted to increase from approximately 150 to 330. CONCLUSIONS: The present study demonstrated that most of the impact of a new trauma system on Victoria's ambulance services could be readily absorbed into the current workload. However, it also highlighted areas affected disproportionately within the ambulance services; in particular, air retrieval. Such studies are important to enable the effective implementation of new trauma systems.

Aged↗
PubMed2001

Usefulness of magnetic resonance-derived quantitative measurements of cerebral blood flow and volume in prediction of infarct growth in hyperacute stroke.

BACKGROUND AND PURPOSE: The identification of the tissue at risk for infarction remains challenging in stroke patients. In this study, we evaluated the value of quantitative cerebral blood flow (CBF) and cerebral blood volume (CBV) measurements in the prediction of infarct growth in hyperacute stroke. METHODS: Fluid-attenuated inversion recovery (FLAIR), diffusion-weighted (DW), and gradient-echo echo-planar perfusion-weighted (PW) sequences were obtained in 66 patients within 6 hours of stroke onset; ischemia was confirmed on follow-up FLAIR images. We delineated the following: (1) the initial infarct on DW images, (2) the area of hemodynamic disturbance on mean transit time (MTT) maps, and (3) the final infarct on follow-up FLAIR images. MTT, CBF, and CBV were calculated in the following areas: area of initial infarct (INF), area of infarct growth (IGR, final minus initial infarct), the hemodynamically disturbed area that remained viable (OLI, hemodynamic disturbance minus final infarct), and all contralateral mirror regions. RESULTS: Compared with mirror regions, the MTT in abnormal areas was always prolonged. The respective mean+/-SD CBF and CBV values were as follows: for INF, 28+/-16 mL/min per 100 g and 6.9+/-2.7%; for IGR, 36+/-20 mL/min per 100 g and 8.9+/-3.1%; for OLI, 50+/-17 mL/min per 100 g and 11.2+/-3%; and for mirror regions, 64+/-23 mL/min per 100 g and 8.7+/-2.5%. The CBV and CBF values were significantly different between all abnormal areas (except for the CBF between INF and IGR). In the area of DW/PW mismatch, a combined CBF or CBV threshold of 35 or 8.2, respectively, predicted evolution to infarction with a sensitivity of 81% and a specificity of 76%. CONCLUSIONS: Quantitative measurements of CBF and CBV in hyperacute stroke may help to predict infarct growth and to select the subjects who will benefit from thrombolysis.

Acute Disease↗
PubMed2001

A model for predicting the future incidence of coronary heart disease within percentiles of coronary heart disease risk.

BACKGROUND: We present a method (The CHD Prevention Model) for modelling the incidence of fatal and nonfatal coronary heart disease (CHD) within various CHD risk percentiles of an adult population. The model provides a relatively simple tool for lifetime risk prediction for subgroups within a population. It allows an estimation of the absolute primary CHD risk in different populations and will help identify subgroups of the adult population where primary CHD prevention is most appropriate and cost-effective. METHODS: The CHD risk distribution within the Australian population was modelled, based on the prevalence of CHD risk, individual estimates of integrated CHD risk, and current CHD mortality rates. Predicted incidence of first fatal and nonfatal myocardial infarction within CHD risk strata of the Australian population was determined. RESULTS: Approximately 25% of CHD deaths were predicted to occur amongst those in the top 10 percentiles of integrated CHD risk, regardless of age group or gender. It was found that while all causes survival did not differ markedly between percentiles of CHD risk before the ages of around 50-60, event-free survival began visibly to differ about 5 years earlier. CONCLUSIONS: The CHD Prevention Model provides a means of predicting future CHD incidence amongst various strata of integrated CHD risk within an adult population. It has significant application both in individual risk counselling and in the identification of subgroups of the population where drug therapy to reduce CHD risk is most cost-effective.

Actuarial Analysis↗
PubMed2001

Selective involvement of the choroid plexus on cerebral magnetic resonance images: a new radiological sign in patients with systemic lupus erythematosus with neurological symptoms.

The selective involvement of the choroid plexus on brain magnetic resonance (MR) images is described in 2 patients with systemic lupus erythematosus presenting with neurological symptoms. The decrease in choroid plexus abnormalities on followup MR examination paralleled the clinical recovery with glucocorticoid therapy in both patients. Our cases indicate that selective involvement of the choroid plexus should be included in the spectrum of the radiological signs for neurological lupus.

Adult↗
PubMed2001

Oncocytic laryngeal cysts: a case report and literature review.

Some 150 cases of oncocytic laryngeal cysts have been published. We report another case of laryngeal oncocytic cysts with atypical presentation of acute, progressive stridor and sore throat. Literature was reviewed with special regard to etiology, clinical presentation, imaging, incidence, localization, associated lesions and treatment options. Oncocytic laryngeal cysts are rare, but may be underreported. They represent a separate clinicopathological entity in the group of all laryngeal cysic lesions and occur in persons over 60 years. The symptomatology varies from asymptomatic to hoarseness and dyspnea. Diagnosis is made by histological examination. Treatment is surgical. Although it is a benign lesion, follow up is recommended, as recurrence is possible.

Acute Disease↗
PubMed2001

Lethal complications after tonsillectomy.

Lethal complications after tonsillectomy. Two cases of serious complications after paediatric tonsillectomy, that were referred to our department, resulted in death, one due to massive haemorrhage and one due to hyponatremia. Thanks to early recognition and adequate treatment, two other cases could be successfully treated. The literature on serious complications after tonsillectomy was critically reviewed. Guidelines on peri- and postoperative fluid management are given. Vascular anatomy of the tonsillar region is reviewed. Location and treatment policy on severe haemorrhages are discussed.

Child↗
PubMed2000

Automatic external defibrillators: changing the way we manage ventricular fibrillation.

OBJECTIVE: To discuss recent developments in automatic defibrillation and to review the evidence that first-responders equipped with automatic external defibrillators (AEDs) improve survival from out-of-hospital cardiac arrest. DATA SOURCES: MEDLINE search from 1966 to 1999 (articles in English only) and examination of bibliographies. STUDY SELECTION: Published studies of out-of-hospital cardiac arrest and first-responders equipped with AEDs. Studies had to have a control group and to report survival to hospital discharge from ventricular fibrillation (VF). DATA EXTRACTION: Six studies met the selection criteria (two prospective randomised trials, two prospective controlled trials, and one cohort study and one retrospective study, both with historical controls). DATA SYNTHESIS: A random effects meta-analysis of odds ratios for survival from VF. CONCLUSIONS: Meta-analysis suggests that equipping first-responders with AEDs increases the probability of survival to hospital discharge after out-of-hospital cardiac arrest (odds ratio, 1.74; 95% CI, 1.27-2.38; P < 0.001). However, most of the studies lacked sufficient power to draw definitive conclusions. Until the impact of wide deployment of AEDs is fully understood, first-responder defibrillation in Australia should only occur as part of coordinated multicentre research studies.

Australia↗
PubMed2000

Simultaneous attainment of high electron and ion temperatures in discharges with internal transport barriers in ASDEX upgrade

Internal transport barriers have been demonstrated to exist also under conditions with T(e) approximately T(i) approximately 10 keV and predominant electron heating of the tokamak core region. Central electron cyclotron heating was added to neutral beam injection-heated ASDEX Upgrade discharges with a preexisting internal transport barrier, established through programmed current ramping leading to shear reversal. Compared to a reference internal transport barrier discharge without electron cyclotron resonance heating, the electron heat conductivity in the barrier region was found not to increase, in spite of a fivefold increase in electron heat flux, and also angular momentum and ion energy transport did not deteriorate.

Journal Article↗
PubMed2000

A compilation of cellular transcription factor interactions with the HIV-1 LTR promoter.

The human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) represents a model promoter system and the identification and characterisation of cellular proteins that interact with this region has provided a basic understanding about both general eukaryotic and HIV-1 proviral transcriptional regulation. To date a large number of sequence-specific DNA-protein interactions have been described for the HIV-1 LTR. The aim of this report is to provide a comprehensive, updated listing of these HIV-1 LTR interactions. It is intended as a reference point to facilitate on-going studies characterising the identity of cellular proteins interacting with the HIV-1 LTR and the functional role(s) of specific regions of the LTR for HIV-1 replication.

DNA-Binding Proteins↗