Molecular epidemiology of poliovirus infection in Tunisia.

This report is an overview of poliomyelitis surveillance in Tunisia from 1991 to 1996. In all, 2088 stool specimens, collected from 152 acute flaccid paralysis (AFP) cases and from 1747 of their healthy contacts were investigated. Virus isolation was done systematically in RD and HEp-2C cell lines and isolated viruses were typed by sero-neutralisation as polioviruses or non-polio enteroviruses.

Obesity: a growing problem.

Obesity, defined as a body mass index (BMI) of 30 kg/m2 or more, is common in many parts of the world, especially in the established market economies, the former socialist economies of Europe, Latin America, the Caribbean and the Middle Eastern Crescent. As many as 250 million people worldwide may be obese (7% of the adult population) and two to three times as many may be considered overweight. The prevalence of obesity seems to be increasing in most parts of the world, even where it used to be rare.

Societal and personal costs of obesity.

The economic costs of obesity can be broken down into three levels: 1. DIRECT COSTS: Costs to the community, related to the diversion of resources to the diagnosis and treatment of diseases directly related to obesity, as well as the treatment of obesity itself. These costs have been estimated to vary between 1-5% of total healthcare costs for various countries.

The potential of restricted access media columns as applied in coupled-column LC/LC-TSP/MS/MS for the high-speed determination of target compounds in serum. Application to the direct trace analysis of salbutamol and clenbuterol.

This study investigated the potential of restricted access media (RAM) columns used as a first column in coupled-column LC hyphenated to thermospray tandem mass spectrometry (LC/LC-TSP/MS/MS) for the fast, selective, and sensitive determination of target drugs in serum samples. Because of their wide range in polarity, salbutamol and clenbuterol were chosen as model compounds and representatives of the class of beta 2-agonists. Three types of RAM columns were tested: (i) Pinkerton ISRP (internal surface reversed phase, 5 microns), (ii) SPS (semipermeable surface, 5 microns C18), and (iii) RP-18 ADS (alkyl-diol silica, 25 microns).

Environmental risk assessment of musk ketone and musk xylene in The Netherlands in accordance with the EU-TGD.

An environmental risk assessment has been carried out for musk ketone and musk xylene according to the EU Technical Guidance Document for Environmental Risk Assessment for New and Existing Substances [1]. Musk ketone and musk xylene are used in fragrances for cosmetics and household products. For the fragrance industry these are important fragrance ingredients because of their excellent substantivity as well as for their unique smell, which determines largely the odor of a product.

Structural identifiability of PBPK models: practical consequences for modeling strategies and study designs.

Physiologically based pharmacokinetic (PBPK) models usually contain unknown parameters that need to be estimated by calibration to concentration-time profiles from in vivo experiments. However, even with error-free data, the number of parameters that can be estimated in this way is limited, depending on the particular situation. This paper introduces the concept of structural identifiability of a model, a requirement to make the estimation of parameters by calibration a meaningful undertaking.

Determination of organochlorine compounds in fatty matrices. Application of rapid off-line normal-phase liquid chromatographic clean-up.

A clean-up method for organochlorine compounds in fatty samples based on normal-phase liquid chromatography (NPLC) is described. To this end, an existing clean-up procedure which uses column switching for the separation of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) from the fat matrix was simplified to a single silica LC column procedure. The use of an LC column packed with 3 microns silica enables complete fat/OCP separation in a total fraction volume of 12 ml, and results in a fully automated clean-up procedure that takes only 32 min per sample.

Noise stress and airway toxicity: a prospect for experimental analysis.

People are exposed to a mixture of chemicals, noise, bad smells and other factors. Little is known about the possible interactions between these various contaminants. Although research on the effects of chemical mixtures has been initiated, the combination of chemical and non-chemical factors has received little attention.

A probabilistic model for deriving soil quality criteria based on secondary poisoning of top predators. II. Calculations for dichlorodiphenyltrichloroethane (DDT) and cadmium.

A simplified food web with three trophic levels is designed: plants and invertebrates at the first, small birds and mammals at the second, and birds and beasts of prey at the third trophic level. Exposure of top predators via separate food chains is analyzed. However, most top predator species are exposed via more than one food chain (food web).

A probabilistic model for deriving soil quality criteria based on secondary poisoning of top predators. I. Model description and uncertainty analysis.

In previous studies, the risk of toxicant accumulation in food chains was used to calculate quality criteria for surface water and soil. A simple algorithm was used to calculate maximum permissable concentrations [MPC = no-observed-effect concentration/bioconcentration factor(NOEC/BCF)]. These studies were limited to simple food chains.

Modeling prevention strategies for gonorrhea and Chlamydia using stochastic network simulations.

A simulation model was used to study the spread of two sexually transmitted diseases (STDs), namely gonorrhea and genital infection with Chlamydia trachomatis. The model is based on a stochastic pair formation and separation process, which describes the underlying structure of the sexual contact pattern. It is implemented as a Monte Carlo simulation model.

Hyphenation of coupled-column liquid chromatography and thermospray tandem mass spectrometry for the rapid determination of beta 2-agonist residues in bovine urine using direct large-volume sample injection. Set-up of single-residue methods for clenbuterol and salbutamol.

In a previous work, coupled-column LC (LC/LC) with direct large-volume sample injection for the analysis of beta 2-agonists in bovine urine was investigated, in view of its combination with thermospray (TSP) tandem mass spectrometric (MS/MS) detection. In this work, the potential of both conventional LC and LC/LC coupled to TSP-MS/MS for the rapid determination of beta 2-agonists in bovine urine was evaluated. It was first established that, in order to avoid disturbances in TSP-MS/MS detection due to changes in pressure and flow rate of the mobile phase, LC/LC is preferable to conventional LC.

Automated solid-phase extraction coupled to gas chromatography with electron-capture detection: a combination of extraction and clean-up of pyrethroids in the analysis of surface water.

The combination of automated solid-phase extraction (SPE) and large-volume introduction gas chromatography electron-capture detection (GC-ECD) is used for the determination of synthetic pyrethroids in surface and drinking water. The selectivity that is needed for the use of GC-ECD of environmental samples is achieved by addition of a polarity modifier to the sample. In this study, sufficient methanol was added to 19 ml of sample to obtain a level of 30% of modifier prior to SPE.

Vero cell assay validation of an alternative to the Ph. Eur. diphtheria potency tests.

In the framework of the Biological Standardisation Programme of the European Pharmacopoeia Commission, in 1993 a collaborative study was organised for the validation of an alternative to the diphtheria in vivo challenge tests required by the Ph.Eur. monograph V.

The impact of obesity on health status: some implications for health care costs.

Obesity (defined as a body mass index > 30 kg/m2) is common in middle-aged Europeans. The prevalence is notably high in women from Mediterranean and Eastern European countries. In most European countries the prevalence of obesity has been shown to be increasing.

Poliomyelitis in The Netherlands: a review of population immunity and exposure between the epidemics in 1978 and 1992.

An overview of serological and virological studies on poliomyelitis in the Netherlands between two epidemics in 1978 and 1992 is given. Three unvaccinated patients acquired poliomyelitis abroad. In the Netherlands vaccination coverage with quadruple DPT-IPV vaccine is very high.

Congener-specific bioavailability of PCDD/Fs and coplanar PCBs in cows: laboratory and field measurements.

To estimate congener-specific bioavailabilities for 17 PCDD/Fs in cows grazing near a MSW incinerator both a controlled lab study and a field study were performed. In the lab study the estimates were derived from the elevated concentrations in milk from two cows after administration of a single dose of contaminated fly ash. In the field study, located near a large MSW incinerator, daily samples of grass and milk collected over a period of 60 days were pooled to two monthly bulk samples.

A measurement of social support in epidemiological research: the social experiences checklist tested in a general population in The Netherlands.

Study Objective: This study aimed to examine in a general population the psychometric qualities of an instrument designed to measure positive and negative social experiences that had been developed in a clinical setting.

Design: The Netherlands monitoring project on cardiovascular disease risk factors, a large scale population based study (comprising 36,588 men and women aged 20 to 59 years) carried out in three Dutch towns (Amsterdam, Doetinchem, and Maastricht) offered the possibility of testing the strength of this instrument cross sectionally.

Measurements And Main Results: The social experiences checklist (SEC) which resulted from a research project on the quality of life of cancer patients was used.

Comparison of adjuvants for immune potentiating properties and side effects in mice.

Four types of adjuvants were evaluated as alternatives to the use of Freund's complete adjuvant in mice. The adjuvants evaluated included a water-in-oil emulsion (Specol), a microorganism (Lactobacillus), performed immune-stimulating complexes (ISCOM) containing rabies virus glycoprotein and a saponin, Quil A. The adjuvants and saline were combined with three weak immunogens (a synthetic peptide, a self antigen and a particulate antigen) and given by three different routes (intraperitoneal, subcutaneous and dorsal in the foot).

Dioxins and related compounds: Status and regulatory aspects.

Several countries have put much effort in dioxin research programmes with the aim to assess the risks of dioxin exposure, to identify dioxin sources and to quantify their contribution to environmental emissions and human exposure. In this review, the accent has been put on: sources of dioxins and their contribution to the total dioxin emissions, sources of human exposure and their contribution to exposure and measures to reduce emission and exposure. The information from countries with existing dioxin regulations is reviewed and compared.

Molecular epidemiology of wild poliovirus type 1 in Europe, the Middle East, and the Indian subcontinent.

The genomic relationships of wild poliovirus type 1 strains recently isolated in Europe, the Middle East, and the Indian subcontinent was analyzed by automated amplicon sequencing of the VP1/2A junction region of the genome. Four major genotypes of poliovirus type 1 were found to circulate. Two genotypes were found predominantly in Eastern Europe, one of these in the Caucasian Region and the other in countries bordering the Black Sea.

An automated gross alpha/beta activity monitor applied to time-resolved quantitative measurements of 222Rn progeny in air.

Automated monitors for the determination of airborne radioactivity are widely in use as early warning systems for nuclear emergencies; however, the data acquired for this purpose are seldom used for analyzing spatial and temporal variations of natural radioactivity (especially radon and short-lived decay products). This paper shows that a specific type of airborne gross alpha/beta activity monitor, applied in several European emergency networks, can be effectively used to study the transport of 222Rn progeny in the outdoor environment. Real-time recordings (10-min sampling time) can, independent of the actual equilibrium ratio, be converted to the equilibrium-equivalent decay-product concentration (EEDC) of 222Rn.