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Biomedical subjects

P Bérard

Publications and source records attributed to P Bérard.

At least 19 recordsLinked to original sources
PubMed2003

Optimising monitoring regimens for inhaled uranium oxides.

This paper provides guidance on the most appropriate monitoring procedures and intervals, the likely uncertainties in the assessment of intake and recommendations on appropriate investigation levels for repeated exposures to uranium trioxide, octoxide and dioxide of natural composition.

Absorption↗
PubMed2003

In vivo measurement of Pu dissolution parameters of MOX aerosols and related uncertainties in the values of the dose per unit intake.

The aim of this study was to compare dissolution parameter values for Pu from industrial MOX with different Pu contents. For this purpose, preliminary results obtained after inhalation exposure of rats to MOX containing 2.5% Pu are reported and compared to those obtained previously with MOX containing 5% Pu. Dissolution parameter values appear to increase when the amount of Pu decreases. Rapid fractions, f(r), of 4 x 10(-3) (s.d. = 2 x 10(-3)) and 1 x 10(-3) (s.d. = 6 x 10(-4)) and slow dissolution rates, s(s) of 2 x 10(-4) d(-1) (standard deviation, sigma = 5 x 10(-5)) and 5 x 10(-5) d(-1) (sigma = 1 x 10(-5)) were derived for MOX containing 2.5 and 5% of Pu, respectively. Simulations were performed to assess uncertainties on dose due to experimental errors. The relative standard deviations of the dose per unit intake (DPUI) due to f(r) (4-8%), are far less than those due to s(s) (about 20%), which is the main parameter altering the dose. Although quite different dissolution parameter values were derived, similar DPUIs were obtained for MOX aerosols containing 2.5 and 5% Pu which appear close to that for default Type S values.

Absorption↗
PubMed2003

Anomalies between radiological and chemical limits for uranium after inhalation by workers and the public.

Exposure limits for workers and the public are based on both chemical toxicity and radiation dose. As a consequence of the different procedures used in their calculation they are incompatible, and adherence to one limit may result in a serious breach of the other. This paper explores the background to these limits, the problems posed by their application and proposes how best to achieve compliance with both limits.

Air Pollutants, Radioactive↗
PubMed2003

Review of methods and computer codes for interpretation of bioassay data.

Internal dose determination is an essential component of individual monitoring programmes for workers or members of the public exposed to radionuclides, and methods and computer programs are required for dose assessment. A recent international European Radiation Dosimetry Group (EURADOS) intercomparison has shown unacceptably large ranges in the results assessment. An ICRP working party has been initiated to consider what guidance ICRP can give on the use of models and interpret bioassay data in terms of intake/dose. In this field, six codes for bioassay data interpretation, which implement the current ICRP publication 78 biokinetic models, have been reviewed against several criteria with different levels of importance: minor criteria such as the practical use of the code and the graphical capabilities, and major criteria such as the choice of available parameters, peculiarities of data fitting and interpretation, the choice of biokinetic models and the use of uncertainties. All these criteria were assessed using one artificial set of data and two examples extracted from the previous international EURADOS intercomparison.

Administration, Oral↗
PubMed2003

OMINEX: survey of internal dose monitoring programmes for radiation workers.

Monitoring of the workforce in the nuclear industries is carried out primarily in order to demonstrate compliance with European Union (EU) legislation and the Basic Safety Standards for the protection of the health of workers against the dangers arising from ionizing radiation recommended by the International Atomic Energy Agency (IAEA). There is, however, no common strategy for internal dose monitoring programmes currently in use in the EU countries. Surveys have been carried out in which organisations were asked to provide information on the design of their internal dose monitoring programmes and on the costs of these programmes. Information was requested from both EU countries and Associated States. Databases for storage and reporting of all gained information were constructed, and results from the surveys have been compiled. This work was carried out within the EC 5th Framework Programme project, OMINEX, which aims to provide advice and guidance on designing and implementing internal dose monitoring programmes in the workplace in such a way that best use is made of available resources, while minimising costs.

Data Collection↗
PubMed2003

Design and implementation of monitoring programmes for internal exposure (project OMINEX).

The costs of monitoring for internal exposure in the workplace are usually significantly greater than the equivalent costs for external exposure. Therefore, there is a need to ensure that resources are employed with maximum effectiveness. The EC-funded OMINEX (optimisation of monitoring for internal exposure) project is developing methods for optimising the design and implementation of internal exposure monitoring programmes. Current monitoring programmes are being critically reviewed, the major sources of uncertainty in assessed internal dose investigated, and guidance formulated on factors such as programme design, choice of method/techniques, monitoring intervals, and monitoring frequency. OMINEX will promote a common, harmonised approach to the design and implementation of internal dose monitoring programmes throughout the EU.

Body Burden↗
PubMed2002

[Specific parameters for the calculation of dose after aerosol inhalation of transuranium elements].

A review on specific parameter measurements to calculate doses per unit of incorporation according to recommendations of the International Commission of Radiological Protection has been performed for inhaled actinide oxides. Alpha activity distribution of the particles can be obtained by autoradiography analysis using aerosol sampling filters at the work places. This allows us to characterize granulometric parameters of "pure" actinide oxides, but complementary analysis by scanning electron microscopy is needed for complex aerosols. Dissolution parameters with their standard deviation are obtained after rat inhalation exposure, taking into account both mechanical lung clearance and actinide transfer to the blood estimated from bone retention. In vitro experiments suggest that the slow dissolution rate might decrease as a function of time following exposure. Dose calculation software packages have been developed to take into account granulometry and dissolution parameters as well as specific physiological parameters of exposed individuals. In the case of poorly soluble actinide oxides, granulometry and physiology appear as the main parameters controlling dose value, whereas dissolution only alters dose distribution. Validation of these software packages are in progress.

Actinoid Series Elements↗
PubMed2001

[Metastatic osteosarcoma: prognosis factors and treatment].

Long term outcome and prognosis factors of patients with metastatic osteosarcoma were evaluated on 29 observations from 3 centres reviewed retrospectively. Twenty-nine patients less than 18 years old were treated from 1990 to 1998. Only 29 of these patients had received similar treatments associating chemotherapy and surgery, adapted according to histological and clinical response to treatment, as recommended by the SFOP. Overall survival at five years was 26%, and disease free survival 14%. Eight patients are alive, four in first complete remission (CR) and four in second CR. Three of the four patients alive in first CR had bone metastases at diagnosis. On univariate analysis, factors predicting survival are: the numbers of organs affected by metastatic lesions, the number of lung nodules and the type of surgery. This is, to our knowledge, the first report of long term survivors with bone metastases at diagnosis. Metastatic osteosarcoma prognosis remain poor. A randomised study would help to define the best possible treatment for this disease.

Adolescent↗
PubMed1999

Implementation of ICP-MS protocols for uranium urinary measurements in worker monitoring.

The uranium concentration in human urine spiked with natural uranium and rat urine containing metabolized depleted uranium was determined by ICP-MS. The use of ICP-MS was investigated without any chemical treatment or after the different stages of a purification protocol currently carried out for routine monitoring. In the case of spiked urine, the measured uranium concentrations were consistent with those certified by an intercomparison network in radiotoxicological analysis (PROCORAD) and with those obtained by alpha spectrometry in the case of the urine containing metabolized uranium. The quantitative information which could be obtained in the different protocols investigated shows the extent to which ICP-MS provides greater flexibility for setting up appropriate monitoring approaches in radiation protection routines and accidental situations. This is due to the combination of high sensitivity and the accuracy with which traces of uranium in urine can be determined in a shorter time period. Moreover, it has been shown that ICP-MS measurement can be used to quantify the 235U isotope, which is useful for characterizing the nature of the uranium compound, but difficult to perform using alpha spectrometry.

Animals↗
PubMed1994

[Surgical treatment of accommodative esotropia].

Since Donders 1862 the treatment of accommodative esotropia is optical: without an hypermetropic correction, the accommodation needed for vision at distance induces a convergence and an accommodative convergence excess at near. But since 130 years, new clinical and physiological research enables us to propose in specific cases a surgical treatment as an alternative to optical treatment. One of the clinical arguments is the low incidence of strabismus in hypermetropic patients: they can see clear at near and at distance without squinting. One of the physiological arguments is the research by J. Semmlow concerning the near triad: his model demonstrates that the system of accommodation and vergence are interconnected: the accommodative system participates to vergence but also the vergence system participates to accommodation, this is less known. The indications, the technique and surgical treatment are exposed. The analysis of the results by G. Gauthier and J.L. Vercher of the "Laboratoire de Contrôles Sensorimoteurs" at Marseille of the measures of the AC/A ratio confirms the model of Semmlow. The vertical syndrome observed in the accommodative squint is supposed to be the most frequent cause of putting the loop of the vergence system open.

Accommodation, Ocular↗
PubMed1993

[Intraoperative radiotherapy in gastric adenocarcinomas. Apropos of 45 cases].

Intra-operative radiation therapy (IORT) is a multidisciplinary approach in which residual tumors or tumor beds are directly irradiated during a surgical procedure. To evaluate its efficacy we conducted since 1985 a prospective study including non metastatic gastric adenocarcinoma treated by surgery, IORT (15 Gy) and post-operative external beam radiotherapy (44 Gy). Up to now, 45 gastric adenocarcinomas (18 pNO and 27 pN1N2) have been included in the study. Mortality and morbidity rates were not different from those of surgery alone. Overall 5 year survival rate is 59.1% and pN1N2 5 years survival rate is 50.6%. These promising results are comparable with those of asian randomized studies which demonstrate the possible value of IORT in the treatment of gastric adenocarcinoma.

Adenocarcinoma↗
PubMed1991

[Value of intraoperative ultrasonography in the surgical treatment of malignant tumors of the liver].

This retrospective study was designed to assess the specific contribution of intraoperative ultrasonography (IOU) in a series of 50 surgical procedures for malignant tumors of the liver (including 27 hepato-cellular carcinomas (HCC) secondary to cirrhosis and 18 metastases). Compared to conventional pre- and intra-operative investigations, IOU was more sensitive (81%) but less specific (27%) for detection of tumor nodules, but was inaccurate in detection of daughter nodules in hepato-cellular carcinomas (HCC) secondary to cirrhosis. The main specific contribution of IOU was assistance in performing surgery. In 14 cases (52%) of HCC secondary to cirrhosis, IOU provided one or several additional pieces of information which resulted in changes of the planned surgical procedure in 11 cases (41%) mainly enabling limited resection of small deep impalpable tumors. In 10 cases (37%), IOU directly guided resection (echo-guided segmentectomy or tumorectomy). Contribution of IOU was poor in primary carcinoma in non-cirrhotic liver, but in 8 cases of metastasis (44%) IOU provided additional information which resulted in changes of the intended surgical procedure in 5 cases (28%) mainly leading to a more extensive resection. Finally IOU was considered to be indispensable in 15 cases of HCC cirrhosis (56%) and in 5 cases of metastasis (28%).

Carcinoma, Hepatocellular↗
PubMed1990

[Role of preoperative radiotherapy in preservation of the anal sphincter in cancer of the lower rectum].

Short term preoperative irradiation of rectal cancer (30 Gy in 12 days) followed by a two-month rest before surgery has proven to be more efficient than most usual protocols of radiotherapy. In a series of 136 tumors T2, T3 or T4, tumor-free specimens and Duke'A lesions were found at surgery in 17% and 36% respectively. Surgeons took advantage of the tumor regression and performed sphincter-saving surgery in 41 patients with T2, T3 or T4 tumors of the lower third of the rectum. Of 30 patients followed from 2 to 6 years, the disease-free survival rate is 86%. Only one local failure was observed and subsequently controlled by abdomino-perineal resection.

Amputation, Surgical↗
PubMed1989

[Simultaneous surgical procedures on the horizontal and vertical muscles in the treatment of convergent strabismus].

In convergent squints the vertical component is very often accompanying the horizontal deviations. This phenomenon is mostly accentuated in congenital squints and in squints very early aquired (onset of squint before the 1st year of life). If after the operation the binocular vision has to be secured indispensable is a surgical procedure which liquidates simultaneously the horizontal as well as the vertical deviation. The operation should be minimally traumatizing; the use of the microscope is most advisable. Preoperative, minute analysis of the motility of the eyes may be performed not earlier than after the child is 2.5 years old. The over mentioned conclusions have been drawn on the basis of analysis of 460 operated cases observed 1 to 5 years.

Accommodation, Ocular↗