Biomedical subjects

Jean-Christophe Thalabard

Publications and source records attributed to Jean-Christophe Thalabard.

9 recordsLinked to original sources

PubMed2006

Cyclical mastalgia and breast cancer risk: results of a French cohort study.

Cyclical mastalgia is a common complaint, with a potentially important relationship to breast cancer risk. In the last decade, case-control studies have reported that cyclical mastalgia could be considered as an independent risk factor for breast cancer. The subjectivity of a retrospectively collected symptom questioned the validity of this finding. We have examined the association between cyclical mastalgia and breast cancer risk in the French cohort study of women with benign breast disease diagnosed in two breast clinics between 1976 and 1979 and followed-up until 1997. The present study was restricted to the women free of any hormonal treatment (n = 247). The mean follow-up was 16 +/- 5 years, and a total of 22 breast cancers occurred during the follow-up. Using a Cox model with duration of cyclical mastalgia as a time-varying variable, the adjusted relative risk of breast cancer increased with the duration of cyclical mastalgia (P = 0.006). The corresponding relative risk for 37 months of cyclical mastalgia was 5.31 (95% confidence interval, 1.92-14.72). We show here that the conclusion still holds when the symptom cyclical mastalgia was collected prospectively in a cohort study, bringing additional evidence that cyclical mastalgia may represent an independent and useful clinical marker of increased breast cancer risk. It might be a confounding factor when assessing the effects of hormonal treatments on breast cancer risk such as hormonal replacement therapy or oral contraceptives.

Adult↗

PubMed2006

A nomogram of fetal lung volumes estimated by 3-dimensional ultrasonography using the rotational technique (virtual organ computer-aided analysis).

OBJECTIVE: The purpose of this study was to build a nomogram of normal fetal lung volumes throughout gestational age estimated by 3-dimensional ultrasonography using the rotational technique (Virtual Organ Computer-Aided Analysis [VOCAL]; GE Healthcare, Kretztechnik, Zipf, Austria). METHODS: Fetal lung volume was assessed in 146 healthy fetuses by 3-dimensional ultrasonography using the technique of rotation of the multiplanar imaging (VOCAL). Inclusion criteria were healthy women with singleton normal pregnancies, normal fetal morphologic ultrasonographic findings, reliable dating established by dates and by ultrasonographic measurement of the crown-lump length in the first trimester, and gestational age from 20 to 37 weeks. Exclusion criteria were discordance between clinical and ultrasonographic dating, patients lost to follow-up, and birth weight disorders. Each patient was scanned once during pregnancy. RESULTS: The right, left, and total mean pulmonary volumes ranged, respectively, from 5.37, 4.66, and 9.95 cm3 at 20 weeks to 46.06, 37.34, and 84.35 cm3 at 37 weeks. The logistic transformation analysis yielded the following formulas: right lung volume = exp(4.07/[1 + exp(21.90 - gestational age/5.44)]); left lung volume = exp(3.82/(1 + exp[22.03 - gestational age/5.17)]); and, total lung volume = exp(4.72/[1 + exp(20.30 - gestational age/6.05)]). CONCLUSIONS: A new nomogram of fetal lung (right, left, and total) volumes throughout gestational age using the rotational technique (VOCAL) is described, and reference values have been generated.

Diagnosis, Computer-Assisted↗

PubMed2004

Progestogen-only contraception in women at high risk of venous thromboembolism.

The objective of the study was to evaluate the venous impact of a progestogen-only contraception on women at high risk of venous thromboembolism (VTE). In this retrospective cohort study, 204 consecutive women at high risk of VTE were recruited between January 1992 and June 1997 and were prospectively followed. Women using chlormadinone acetate (CMA) at antigonadotropic doses (n=102) were matched by age and date of referral and history of venous thrombosis with women who had no hormonal contraception (n=102). During follow-up (mean of 33 months), nine episodes of VTE were observed: three in women receiving CMA and six in nontreated women. Using the Cox model to adjust for confounding variables such as age, thrombophilia and body mass index, the relative risk of VTE associated with the use of CMA was not significant [relative risk: 0.8 (0.2-3.9)]. These reassuring results need to be confirmed in other prospective studies.

Adult↗

PubMed2004

Three-dimensional ultrasonographic assessment of fetal lung volume as prognostic factor in isolated congenital diaphragmatic hernia.

OBJECTIVE: To evaluate the potential of three-dimensional ultrasound to predict outcome in congenital diaphragmatic hernia. DESIGN: Prospective observational study. SETTING: Tertiary care centre. POPULATION: Twelve cases of isolated congenital diaphragmatic hernia (11 left-sided, 1 right-sided) and 109 controls. METHODS: Fetal lung volume was assessed by three-dimensional ultrasound using the technique of rotation of the multiplanar imaging. In the control fetuses, a logistic transformation was performed to correlate fetal lung volume with gestational age, and the confidence interval was obtained with a bootstrap resampling. A mathematical equation was then obtained allowing calculation of the expected fetal lung volume as a function of gestational age. In fetuses with congenital diaphragmatic hernia, the observed/expected lung volume ratio was compared with postnatal outcome. MAIN OUTCOME MEASURES: Neonatal mortality and pulmonary hypoplasia, which was defined as lung/body weight ratios less than 0.012. RESULTS: The expected fetal lung volume was derived from the mathematical equation: Fetal lung volume (mL) = exp (4.72/(1 + exp ((20.32 - gestational age in weeks)/6.05))). The observed/expected fetal lung volume ratio was significantly lower in the congenital diaphragmatic hernia group (median: 0.34, range: 0.16-0.66), than in the control group (median: 1.02, range: 0.62-1.97, P < 0.0001). The distribution of this ratio was significantly downshifted in the infants with congenital diaphragmatic hernia who died (median: 0.19, range: 0.18-0.66) compared with survivors (median: 0.44, range: 0.36-0.66, P= 0.04). The observed/expected fetal lung volume ratio was also correlated with the postmortem lung/body weight ratio. CONCLUSION: In isolated congenital diaphragmatic hernia, fetal lung volume measurement by three-dimensional ultrasound is a potential predictor for pulmonary hypoplasia and postnatal outcome.

Female↗

PubMed2004

Fetal lung volume estimated by 3-dimensional ultrasonography and magnetic resonance imaging in cases with isolated congenital diaphragmatic hernia.

OBJECTIVE: To assess the agreement of 3-dimensional ultrasonography and magnetic resonance imaging in estimating fetal lung volume in cases with isolated congenital diaphragmatic hernia. METHODS: Fetal lung volume was measured in 11 cases of congenital diaphragmatic hernia (10 left and 1 right) by 3-dimensional ultrasonography and magnetic resonance imaging. These examinations were performed during the same week. The operators were blinded to each other's results. Intraclass correlation was used to evaluate the agreement between 3-dimensional ultrasonography and magnetic resonance imaging estimations of the ipsilateral, contralateral, and total fetal lung volume. A Bland-Altman graph was plotted to detect possible discordant observations. RESULTS: The global intraclass correlation coefficient between magnetic resonance imaging and 3-dimensional ultrasonographic measurement of fetal lung volume was 0.94 (95% confidence interval, 0.78-0.98) with no outliers observed on the Bland-Altman plot. CONCLUSIONS: There is a good agreement between 3-dimensional ultrasonography and magnetic resonance imaging for fetal lung volume estimation in cases with congenital diaphragmatic hernia.

Adult↗

PubMed2002

Detection and false-positive rates of maternal serum markers for Down syndrome screening according to maternal age in women over 35 years of age. A study of the agreement of eight dedicated software packages.

Maternal serum markers for trisomy 21 screening (MSS) can be assayed in women > or =35 years in an attempt to reduce the need for invasive procedures and thereby avoid their side effects. Our objective was to compare, in women > or =35, eight different software packages dedicated to second trimester MSS, thus providing reliable data for patient counselling. A simulation study was carried out on 189 sera from women with Down syndrome fetuses and 11 962 sera from mothers of unaffected babies. The first step was to estimate the joint distribution of alpha-fetoprotein (AFP) and free beta-human chorionic gonadotrophin (beta-hCG). The second step was to calculate trisomy 21 detection and false-positive rates for each software according to maternal age (35-45 years), using the usual 1:250 risk threshold. Agreement between software packages was measured using 2 x 2 kappa coefficients. Detection rates and false-positive rates increased with maternal age. Depending on the software, 57-71% detection rates were achieved at 35 years with 12-18% false-positive rates. At 45 years, 61-100% detection rates were achieved with 66-95% false-positive rates. Up to 39 years, all softwares were concordant (kappa coefficients >0.75). In the range 35-45 years, false-positive and detection rates increased substantially with maternal age and differences between software packages are observed.

Adult↗

PubMed2002

Contribution of a mathematical modelling approach to the understanding of the ovarian function.

The biological meaning of folliculogenesis is to free fertilisable oocytes at the time of ovulation. We approached the study of the control of follicular development at the level of follicular granulosa cells, on the experimental as well as mathematical modelling grounds. We built a mathematical model allowing for the processes of proliferation, differentiation and apoptosis. State variables correspond to the numbers of cells undergoing these different processes, while control variables correspond to the cellular transition rates. The model results raised the notion of proliferative resources, which leads to consider the optimal management of these resources and has motivated the settling of an experiment investigating the changes in the growth fraction within the granulosa throughout terminal development. We are now investigating the way gonadotrophins, and especially FSH, operate on granulosa cells, in order to account for the hormonal control of the divergent commitment of granulosa cells towards either proliferation, differentiation or apoptosis. We are thus focusing on the dynamics of cAMP production, which appears to be a keypoint in FSH signal transduction.

Animals↗

PubMed2002

Amniotic fluid beta-endorphin: a prognostic marker for gastroschisis?

PURPOSE: The aim of this work was to study amniotic fluid beta-endorphin as a potential predictor for postnatal morbidity in gastroschisis. METHODS: Beta-endorphin was assayed in 43 amniotic fluid samples from 13 pregnant women with fetal gastroschisis undergoing diagnostic amniocentesis or therapeutic amnioinfusion and compared with 33 controls. Within the gastroschisis group, the authors investigated the relationship between postnatal morbidity and the peak value of amniotic fluid beta-endorphin (AFBE). RESULTS: Ten AFBE values in 6 cases of gastroschisis were above the upper limit of the 95% confidence interval derived from controls. Postnatal morbidity was significantly higher when peak AFBE exceeded 10 microg/L (n = 4 pregnancies) compared with below 5 microg/L (n = 9 pregnancies), as shown by mean duration of mechanical ventilation (15.2 v 3 days; P =.01), of parenteral feeding (77 v. 18.7 days; P =.04), and of hospitalization (84 v 32.2 days; P =.04). There was no statistically significant association between postnatal morbidity markers and prenatal dilation of fetal bowel. CONCLUSIONS: The most severe cases of gastroschisis are associated with high levels of AFBE. The authors speculate that this fetal hormonal response could result from stress or pain caused by prenatal bowel damage.

Amniocentesis↗

PubMedDate not supplied

Methodology for small clinical trials.

Small clinical trials are trials in which the number of patients does not enable the objective of the study to be appropriately met with the usual methodological rules. This situation is common in the case of rare diseases, in paediatrics, in certain cancer pathologies or when the number of patients exposed to the treatment needs to be limited. The principal methodological problems are initially identified, and the classical methods (controlled, randomised, double-blind trial using parallel groups, crossover trial, factorial design, trial performed with several measures repeated over time, add-on design, randomised withdrawal design or early-escape design) and more uncommon methods (sequential approaches, meta-analyses, the 'N of 1' method and other methods that facilitate decision making or modelling) are then discussed. Subsequently, recommendations are made to ensure that the results obtained are not a matter of chance, and to increase the level of proof.

Clinical Trials as Topic↗