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Biomedical subjects

P Verger

Publications and source records attributed to P Verger.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Assessment of intake from the diet.

Exposure assessment is one of the key parts of the risk assessment process. Only intake of toxicologically significant amounts can lead to adverse health effects even for a relatively toxic substance. In the case of chemicals in foods this is based on three major aspects: (i) how to determine quantitatively the presence of a chemical in individual foods and diets, including its fate during the processes within the food production chain; (ii) how to determine the consumption patterns of the individual foods containing the relevant chemicals; (iii) how to integrate both the likelihood of consumers eating large amounts of the given foods and of the relevant chemical being present in these foods at high levels. The techniques used for the evaluation of these three aspects have been critically reviewed in this paper to determine those areas where the current approaches provide a solid basis for assessments and those areas where improvements are needed or desirable. For those latter areas, options for improvements are being suggested, including, for example, the development of a pan-European food composition database, activities to understand better effects of processing on individual food chemicals, harmonisation of food consumption survey methods with the option of a regular pan-European survey, evaluation of probabilistic models and the development of models to assess exposure to food allergens. In all three areas, the limitations of the approaches currently used lead to uncertainties which can either cause an over- or underestimation of real intakes and thus risks. Given these imprecisions, risk assessors tend to build in additional uncertainty factors to avoid health-relevant underestimates. This is partly done by using screening methods designed to look for "worst case" situations. Such worse case assumptions lead to intake estimates that are higher than reality. These screening methods are used to screen all those chemicals with a safe intake distribution. For chemicals with a potential risk, more information is needed to allow more refined screening or even the most accurate estimation. More information and more refined methods however, require more resources. The ultimate aims are: (1) to obtain appropriate estimations for the presence and quantity of a given chemical in a food and in the diet in general; (2) to assess the consumption patterns for the foods containing these substances, including especially those parts of the population with high consumption and thus potentially high intakes; and (3) to develop and apply tools to predict reliably the likelihood of high end consumption with the presence of high levels of the relevant substances. It has thus been demonstrated that a tiered approach at all three steps can be helpful to optimise the use of the available resources: if relatively crude tools - designed to provide a "worst case" estimate - do not suggest a toxicologically significant exposure (or a relevant deficit of a particular nutrient) it may not be necessary to use more sophisticated tools. These will be needed if initially high intakes are indicated for at least parts of the population. Existing pragmatic approaches are a first crude step to model food chemical intake. It is recommended to extend, refine and validate this approach in the near future. This has to result in a cost-effective exposure assessment system to be used for existing and potential categories of chemicals. This system of knowledge (with information on sensitivities, accuracy, etc.) will guide future data collection.

Animals↗
PubMedDate not supplied

The congenital anomalies registry in Belarus: a tool for assessing the public health impact of the Chernobyl accident.

A national population-based malformation registry (BNR) has been in operation since 1979 in Belarus, one of the countries most heavily exposed to the contamination from the Chernobyl accident of 26 April 1986. We describe its methodology and its compliance with established criteria, evaluate the completeness of its reporting, and analyze the data collected in four administrative regions with contrasting contamination levels from 1983 through 1999. Nine easily diagnosed malformations have been monitored since 1983. Reporting completeness exceeds 85% for all periods and all regions. In all periods, the prevalence at birth of these malformations was lower in the most contaminated regions and showed a similar positive time trend in areas of low and high contamination. We conclude that the BNR is a reliable tool for studying the possible effects on congenital malformations caused by the Chernobyl accident. Although the trend we observed may be explained by better ascertainment and prenatal diagnosis, a real increase cannot be ruled out.

Adult↗
PubMedDate not supplied

Interferon and ursodeoxycholic acid combined therapy in chronic viral C hepatitis: controlled randomized trial in 203 patients.

AIMS: This prospective randomized trial was carried out in order to determine whether the long-term administration of ursodeoxycholic acid after discontinuation of interferon had any beneficial effect on the clinical course of hepatitis C virus infection. METHODS: Enrolled in the study were 203 patients with chronic active hepatitis C. They were all given: interferon alpha-2a (3 MU subcutaneously thrice a week) and ursodeoxycholic acid (10 mg/kg/day) for 9 months. At month 9, biochemical responders only were randomized into ursodeoxycholic acid treatment or placebo for 12 additional months (double blind study). RESULTS: At the end of interferon therapy, 71 patients (37%) were virological responders and 107 (56%) patients were biochemical responders and were randomized: 54 into the ursodeoxycholic acid group and 53 into the placebo group. Sustained response was evaluated 12 months after withdrawal of interferon. Sustained biochemical and virological responses were, respectively, 30% and 22% in the ursodeoxycholic acid group and 46% and 32% in the placebo group, which did not significantly differ. Histological evolution of fibrosis and necrotic inflammatory activity were similar in the two groups. CONCLUSION: Continuation of ursodeoxycholic acid therapy after withdrawal of interferon in patients with end-of-treatment response did not result in any significant improvement either in the maintenance of response to interferon or in liver histology.

Adolescent↗
PubMedDate not supplied

One example of utilization of the 'French approach'.

This paper presented the French scientific approach to the monitoring of food additive consumption. This method consists of two steps: a first level for the detection of the risk; and a second level for a more refined estimation of additive consumption. The first step, referred to as the 'crude method' consists of using food consumption by real consumers, and a maximal authorized level for additives in each category of food. This observed mean is multiplied by a factor of 3 to evaluate the intake of high consumers. Then, when a problem is indicated, a precise evaluation is necessary. For this second step, information from food manufacturers about the real level of the utilization of additives would be useful.

Food↗
PubMedDate not supplied

[Evaluation of the psychological consequences of environmental catastrophes: a feasibility study based on the 1992 floods in the Vaucluse].

Scientific studies of environmental disasters, whether human or natural in origin, have shown that the psychological impact of such events may be considerable and long-lasting. Several natural disasters have occurred in France, but their impact on public psychological health has not been assessed. In September 1992, there was a major flood in southeast France (Vaucluse), which caused 38 deaths. Four years later, we performed a pilot cross-sectional study to assess the feasibility of a larger epidemiological study to assess the psychological impact of this flood. Two affected towns were chosen for this study: Vaison-la-Romaine (VLR), where the flood was very sudden and 29 people were killed, and Bédarrides, where the water level rose more slowly. In Bédarrides, households were randomly selected from a list of victims (n = 100) and in Vaison-la-Romaine, households were randomly selected from the telephone directory (n = 140). Exposure to the flood was assessed by a series of questions, the answers to which were used to calculate an exposure score. The questionnaire also included psychometric scales for post-traumatic stress disorder (QE-PTSD), anxiety (Spielberger State-Trait Anxiety Inventory) and depression (Beck Depression Inventory). In Bédarrides, the participation rate was high: 69% of the selected households were successfully contacted and found to be eligible for inclusion and 74% agreed to a face-to-face interview. In Vaison-la-Romaine, 51% of the selected households were contacted and eligible and 50% agreed to the face-to-face interview. Our survey showed that exposure was multidimensional and that it was possible to calculate an exposure score suitable for the analysis of exposure-effect relationships. The PTSD scale was completed well by the interviewees, several of whom did not fill in the depression and anxiety scales correctly. However, analysis of the responses obtained showed that these tools had a high level of internal consistency. Cross-correlations between the various psychological scales used in this study were highly significant (p < 10-4). There was some degree of association between some psychometric scales and exposure. This pilot study shows that a cross-sectional study of the long-term psychological consequences of an environmental disaster could be carried out several years after the event but that the feasibility of such a study depends ultimately on its acceptance by the public and the relevant authorities. It underlines the need to collect exposure data immediately after the event and enabled us to identify and to adapt the tools required for this kind of evaluation. It should encourage public health decision-makers to support such evaluation and to improve the psychological and social support available to people exposed to floods.

Anxiety↗
PubMedDate not supplied

[Down syndrome and ionizing radiation: causal effect or coincidence].

Annual and monthly prevalence of Down's Syndrome has been analyzed in Belarus for a 19-year period (1981 to 1999). The distribution of 2786 DS cases during this period showed no significant long-term prevalence trend. Meanwhile, 2 marked increases of DS prevalence were registered in 1987 and 1990. The most remarkable annual increases were observed in 1987 in Minsk city, in Vitebsk oblast (considered as contamination-free administrative district) and in Minsk oblast (partially contaminated area), data not shown in the text. Much more marked and significant increases were recorded in January 1987, in Minsk city, Gomel oblast and Minsk oblast. However it is impossible to establish a causal relationship between these clusters of DS and exposure to the Chernobyl fallout, at a geographical level. The presence of such a cluster 9 months after the explosion in one of the most exposed area (Gomel oblast) should incite to careful conclusions and prompt further studies.

Cluster Analysis↗
PubMedDate not supplied

[Results of brain tomography in acute lymphoblastic leukemia in children].

Computerised axial tomography (CAT scan) was performed in 22 children with acute lymphoblastic leukaemia and in 13 the results were normal. In the other nine, various lesions were observed; namely intra-parenchymal lesions of density of (3 cases, one of which was calcified), intra-parenchymal lesions of decreased density (2 cases) and ventricular dilatation (7 cases). The role of the disease and of the treatment (intra-thecal methotrexate, cranial irradiation) in the development of these lesions is discussed. The CAT scan is an excellent method of monitoring the neurological problems in acute lymphoblastic leukaemia.

Adolescent↗