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P De Bièvre

Publications and source records attributed to P De Bièvre.

8 recordsLinked to original sources
PubMed2000

"Demonstration" vs. "designation" of measurement competence: the need to link accreditation to metrology.

Formal acceptance of the results of chemical laboratories is increasingly organized through a) accreditation of measuring laboratories nationally and b) mutual recognition of accreditation internationally (through formal Multilateral Recognition Agreements, MRAs). However, real comparability of results of measurements is realized by using common (internationally agreed) measurement scales which make these results traceable to this scale, i.e. "traceable" to the same (internationally agreed) value of the unit of that scale. In addition, the criterion against which the evaluation is done, should be "external" to the measurement laboratories which are being evaluated. This is realized in IRMM's International Measurement Evaluation Programme (IMEP) where evaluation is performed against values which are anchored using "metrology", the science of measurement with its own rules, which offers a sound foundation for measurement in all scientific disciplines. It is argued in this paper that the demonstration of measurement capability against values on such scales provides a result-oriented rather than a procedure-oriented evaluation. Thus, competence can be "demonstrated" rather than just "designated" and this can be shown to both customers and regulators. It inspires more confidence.

Journal Article↗
PubMed1998

[Use of ultrasonography as a first-line investigation of the uterus. Results of a prospective study].

OBJECTIVE: To assess the effectiveness of hysterosonography as a first line investigation for uterine bleeding in perimenopausal women. METHODS: 185 women were enrolled in a prospective study. They underwent a hysterosonography indicated for abnormal uterine bleeding or follow-up of a treatment with tamoxifene. Patients with a normal cavity or atrophia were scheduled for a diagnostic hysteroscopy or a hormonal therapy. Patients with uterine cavity abnormalities were scheduled for surgery (operative hysteroscopy or hysterectomy). All the patients were clinically followed after the hysterosonography or the surgery. Results of hysterosonography were compared to data issued from the clinical follow-up or to pathological results when available. RESULTS: Hysterosonography was achieved in 179 patients. In all but 1 case, hysterosonography was well tolerated by the patients. We had no complication during or after the examination. Hysterosonography had a high sensitivity and specificity in the discrimination of women with normal cavity or atrophia from the ones with intrauterine lesions (respectively 96.4% and 98.3%). Hysterosonography was also accurate in the distinction of polyps from sub-mucosal myomas (sensitivity 88.2 à 90.3%, specificity: 98.6 à 95%). The measurement and localization of the lesions were accurate in an equal manner with both procedures. Hysterosonography had similar results in women treated with tamoxifene, but the failure frequency was significantly higher (13% vs 1.8%) (p < 0.05). CONCLUSIONS: Hysterosonography appears as a reliable tool for the investigation of abnormal uterine bleeding in perimenopausal women. It can distinguish women who just need a medical therapy from the ones who will require a surgical exploration. It is easy to learn, and well tolerated by the women. Hysterosonography is more sensitive and specific than transvaginal sonography in the follow-up of patients treated with Tamoxifene.

Adult↗
PubMed1997

Microinvasive carcinoma of the cervix. Rationale for conservative treatment in early squamous cell carcinoma.

Numerous definitions of microinvasive carcinoma (MIC) have been proposed. Taking into account that a classification must be a guide for the evaluation of prognosis and treatment, the authors reviewed the risk of spread in MIC. Two major prognostic factors can be identified in the literature: the volume of the lesion and the presence of capillary-like space involvement (LVI). The former item is generally assessed by the depth of invasion. Two kinds of MIC can be distinguished. Those with stromal invasion under 3 mm and without LVI, and those with invasion over 3.1 mm depth or LVI. The former have little risk of parametrial and nodal involvement and a high rate of survival. The latter have a greater risk of spread beyond the cervix and many authors now consider them as true invasive cancers. The Society of Gynaecologic Oncologists (SGO) definition seems more reliable. For lesions invading the stroma within 3 mm, treatment can be limited to a standard hysterectomy with good results. Some authors have proposed more conservative therapy such as conization. This procedure could be desirable for young women who want to preserve their anatomical integrity, fertility and sexual function. In selected cases, short term results are similar to those of hysterectomy but there is a lack of controlled studies with long term follow-up.

Carcinoma, Squamous Cell↗
PubMed1996

Traceable values for nitrate in water samples by isotope dilution analysis using a small thermionic quadrupole mass spectrometer.

An isotope dilution mass spectrometric procedure was developed for the determination of nitrate in water samples. The isotope dilution experiments were carried out using the Institute for Reference Materials and Measurements's 15N-enriched nitrate spike reference material IRMM-627. Nitrate was isolated from the matrix by precipitating it as nitron nitrate, from which emission of negative thermal NO2-ions was found to be best. The ions were produced in the ion source of a small, low-cost, easy-to-handle thermionic quadrupole mass spectrometer equipped with a secondary electron multiplier coupled to an ion counter. The procedure developed was applied to the measurement of nitrate in a certified reference material (stimulated rainwater, CRM 409 from Community Bureau of Reference), in sparkling mineral water, and in tap water. Results were compared with those obtained using ion chromatography. Good agreement (within 1%) was found between the concentration determined by isotope dilution mass spectrometry, the values from ion chromatography, and the certified value. The procedure developed allowed accurate and traceable determinations of nitrate in water samples, with an expanded uncertainty (coverage factor k = 2) of 2-5%, and the detection limit was found to be 2 mumol kg-1.

Chromatography, Ion Exchange↗
PubMed1994

[The "hazards" of using a Gore-Tex sling in the treatment of stress urinary incontinence].

OBJECTIVE: To analyze the use of the Gore-Tex in the treatment of exertion incontinence. METHODS: During 1991, two gynecology units used the Mouchel technique and a Goebell-Stoeckel type technique in 72 patients with exertion incontinence, alone in 36 and in combination with a cure for prolapsus in 36 others. Results were analyzed with the chi 2 squared test and the Student's test for paired series. RESULTS: The rate of incontinence was 65% with a range from 60 to 66.7% according to the type of technique used and whether a cure for prolapsus was also performed. Gore-Tex was not well tolerated in 23/72 cases. Rejection was seen in 20 to 37.5% according to the type of vaginal suture and the type of protection. CONCLUSION: The high rate of rejection suggests prudence in using Gore-Tex.

Adult↗
PubMedDate not supplied

Comparative performance study of ICP mass spectrometers by means of U "isotopic measurements".

The performance of four commercially available ICPMS instruments of three different types was compared by means of uranium "isotopic measurements". Examined were two quadrupole sector (different generation, different manufacturer), one single detector double focusing magnetic sector and one multiple collector double focusing magnetic sector instruments. The same samples of the IRMM-072 series were used under routine conditions to measure the 233U/235U and the 233U/238U ratios which, in these samples, vary over almost three orders of magnitude from approximately 1 to approximately 2 x 10(-3). Within expanded (k = 2) uncertainties, good agreement was observed between the certified values and the data internally corrected for mass-discrimination effects. The magnitude of the evaluated uncertainties was different for each type of instrument. With the multiple collector instrument, expanded uncertainties varied from +/- 0.04% to +/- 0.24% for the 233U/235U ratio, and from +/- 0.08% to +/- 0.27% for the 233U/238U ratio. They were approximately 1 to 5 times larger with the single detector magnetic sector instrument, and approximately 10 to 25 times larger with both quadrupole sector instruments. With the multiple collector instrument, repeatability of the measurements seemed to be limited by the difficulty of correcting properly for instrumental background, whereas with the single detector magnetic sector instrument the counting statistics was the only limitation (on smallest ratios). Apparent mass-discrimination was clearly found to be larger but more reproducible (and hence easier to correct for) in the case of magnetic sector instruments than for both quadrupole sector instruments. If space charge effects were the main source of mass-discrimination for all instruments, these results are in contradiction with the hypothesis of the size of mass-discrimination decreasing with the acceleration voltage. With the single detector magnetic sector instrument in particular (when operated by changing the ion energy only), our results pointed at more than only one major source of mass-discrimination, with variable size depending on the ratios measured.

Journal Article↗