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Biomedical subjects

Philippe Bouchard

Publications and source records attributed to Philippe Bouchard.

18 recordsLinked to original sources
PubMed2007

Novel FGFR1 sequence variants in Kallmann syndrome, and genetic evidence that the FGFR1c isoform is required in olfactory bulb and palate morphogenesis.

In a new cohort of 141 unrelated patients affected by Kallmann syndrome we identified FGFR1 sequence variants in 17 patients, all in the heterozygous state. The fifteen novel variants consist of 10 missense (p.N77K, p.C101F, p.R250W, p.G270D, p.P283R, p.S332C, p.H621R, p.S685F, p.I693F, p.R822C), two nonsense (p.E324X, p.R661X), a frameshift (p.S439fs), and two splice site (c.1081G>C and c.1977+1G>A) changes. However, the p.N77K and p.R822C changes were also found in two and one out of 150 healthy control individuals, respectively, and therefore, their pathogenic effect is questionable. Notably, three alterations (p.E324X, p.S332C, c.1081G>C) are located in the alternative exon 8B that codes for the FGFR1c isoform, thus indicating that this isoform plays a crucial role in the development of the olfactory system in man. Moreover, the presence of cleft palate in a patient carrying the p.E324X change shows that FGFR1c is important for palate morphogenesis too.

DNA Mutational Analysis↗
PubMed2006

Kallmann syndrome: mutations in the genes encoding prokineticin-2 and prokineticin receptor-2.

Kallmann syndrome combines anosmia, related to defective olfactory bulb morphogenesis, and hypogonadism due to gonadotropin-releasing hormone deficiency. Loss-of-function mutations in KAL1 and FGFR1 underlie the X chromosome-linked form and an autosomal dominant form of the disease, respectively. Mutations in these genes, however, only account for approximately 20% of all Kallmann syndrome cases. In a cohort of 192 patients we took a candidate gene strategy and identified ten and four different point mutations in the genes encoding the G protein-coupled prokineticin receptor-2 (PROKR2) and one of its ligands, prokineticin-2 (PROK2), respectively. The mutations in PROK2 were detected in the heterozygous state, whereas PROKR2 mutations were found in the heterozygous, homozygous, or compound heterozygous state. In addition, one of the patients heterozygous for a PROKR2 mutation was also carrying a missense mutation in KAL1, thus indicating a possible digenic inheritance of the disease in this individual. These findings reveal that insufficient prokineticin-signaling through PROKR2 leads to abnormal development of the olfactory system and reproductive axis in man. They also shed new light on the complex genetic transmission of Kallmann syndrome.

Chromosome Segregation↗
PubMed2006

The membrane skeleton in Paramecium: Molecular characterization of a novel epiplasmin family and preliminary GFP expression results.

Previous attempts to identify the membrane skeleton of Paramecium cells have revealed a protein pattern that is both complex and specific. The most prominent structural elements, epiplasmic scales, are centered around ciliary units and are closely apposed to the cytoplasmic side of the inner alveolar membrane. We sought to characterize epiplasmic scale proteins (epiplasmins) at the molecular level. PCR approaches enabled the cloning and sequencing of two closely related genes by amplifications of sequences from a macronuclear genomic library. Using these two genes (EPI-1 and EPI-2), we have contributed to the annotation of the Paramecium tetraurelia macronuclear genome and identified 39 additional (paralogous) sequences. Two orthologous sequences were found in the Tetrahymena thermophila genome. Structural analysis of the 43 sequences indicates that the hallmark of this new multigenic family is a 79 aa domain flanked by two Q-, P- and V-rich stretches of sequence that are much more variable in amino-acid composition. Such features clearly distinguish members of the multigenic family from epiplasmic proteins previously sequenced in other ciliates. The expression of Green Fluorescent Protein (GFP)-tagged epiplasmin showed significant labeling of epiplasmic scales as well as oral structures. We expect that the GFP construct described herein will prove to be a useful tool for comparative subcellular localization of different putative epiplasmins in Paramecium.

Amino Acid Sequence↗
PubMed2006

Mutations and sequence variants in GDF9 and BMP15 in patients with premature ovarian failure.

BACKGROUND AND OBJECTIVE: Mutations in bone morphogenic protein 15 (BMP15) and growth/differentiation factor 9 (GDF9) lead to altered fertility in animal models. In the human, a heterozygous point mutation of BMP15 has been associated with premature ovarian failure (POF). SUBJECT AND METHODS: We have directly sequenced both genes in a cohort of 203 POF patients presenting with primary or secondary amenorrhea and high FSH levels and in a control population including 54 women with regular menstrual cycles who had at least one child. RESULTS: We have identified several heterozygous variants. One alteration in GDF9 (S186Y) and one in BMP15 (L148P) may have pathogenic effects as both positions are conserved in vertebrate species, ranging from the chicken to mammals. These variants were absent in the control samples. We also found synonymous and neutral substitutions. CONCLUSIONS: We propose that although mutations in BMP15 and GDF9 are not a major cause of ovarian insufficiency, they may be involved in POF.

Adult↗
PubMed2006

Risk assessment for severe clinical attachment loss in an adult population.

BACKGROUND: This study was carried out to identify variables related to severe clinical attachment loss (CAL) in an adult French population. METHODS: This cross-sectional survey employed 2,132 subjects of the First National Periodontal and Systemic Examination Survey (NPASES I) aged 35 to 64 years, each with at least six teeth. A nationally representative sample was obtained from September 2002 to June 2003 by a quota method stratified on age, gender, socioeconomic status, and geographic areas. The subjects had a complete full-mouth periodontal examination of four sites per tooth, assessment of missing teeth, and a number of laboratory tests and questionnaires. The periodontal status of each subject was assessed by criteria based on the severity and extent of CAL. The data were analyzed by univariable and multivariable models using logistic regression analyses. RESULTS: Nineteen and seven-tenths percent (19.7%) of the subjects had CAL>5 mm. When dental variables were not included in the analysis (model 1), age (odds ratio [OR]=1.8), male gender (OR=1.7), body mass index (OR=1.2), and white blood cell count (OR=2.2) showed significant association with severe CAL. A significantly higher risk was also present in non-drinkers and regular drinkers compared to occasional drinkers (OR=1.6). Model 2, including dental variables in addition to model 1 variables, showed that a significantly higher risk for severe CAL was also present with age (OR=1.6) and in males (OR=1.7). The number of teeth (OR=1.1), and the mean gingival bleeding index (OR=1.7) were the dental variables significantly associated with severe CAL. CONCLUSIONS: The results indicated that age and gender are powerful independent predictors of clinical attachment loss, as is the mean gingival bleeding index. To a lesser extent, the number of missing teeth was a good predictive variable. The patient profile for severe clinical attachment loss also included body mass index and white blood cell count. Occasional drinking may be associated with decreased severity of CAL.

Adult↗
PubMed2005

Selective progesterone receptor modulators and progesterone antagonists: mechanisms of action and clinical applications.

Since the discovery of the antiprogestin mifepristone, hundreds of similar compounds have been synthesized, which can be grouped in a large family of progesterone receptor ligands. This family includes pure agonists such as progesterone itself or progestins and, at the other end of the biological spectrum, pure progesterone receptor antagonists (PA). Selective progesterone receptor modulators (SPRM) have mixed agonist-antagonist properties, and occupy an intermediate position of the spectrum. These compounds have numerous applications in female health care. Mifepristone is used to terminate pregnancy, and as such is commercially available in many countries. The negative abortion-related image of mifepristone has clearly limited the involvement of the major pharmaceutical companies in the development of PA and SPRM. Many PA and SPRM display direct antiproliferative effects in the endometrium, although with variable actions which seem product- and dose-dependent. This property justifies their use in the treatment of myomas and endometriosis. PA also suppress late follicular development, block the LH surge and retard endometrial maturation, which renders them potential estrogen-free contraceptive drugs. SPRM such as asoprisnil are not as effective in blocking the LH surge and appear to target the endometrium directly and produce amenorrhoea. Interestingly, clinical data show that treatment with these compounds is not associated with hypo-estrogenism and bone loss. The potential clinical applications of these compounds cover a broad field and are very promising in major public health areas. These include emergency contraception, long-term estrogen-free contraception (administered alone, or in association with a progestin-only pill to improve bleeding patterns), myomas (where they induce a marked reduction in tumour volume and produce amenorrhoea) and endometriosis. Further developments might also include hormone replacement therapy in post-menopausal women, as well as the treatment of hormone-dependent tumours.

Endometriosis↗
PubMed2005

Kallmann syndrome: 14 novel mutations in KAL1 and FGFR1 (KAL2).

Kallmann syndrome (KAL) combines hypogonadotropic hypogonadism and anosmia. Hypogonadism is due to Gonadotropin Releasing Hormone (GnRH) deficiency and anosmia is related to hypoplasia of the olfactory bulbs. Occasional symptoms include renal agenesis, bimanual synkinesia, cleft lip palate, dental agenesis. KAL is genetically heterogeneous and two genes have so far been identified, namely KAL1 (Xp22.3) and FGFR1/KAL2 (8p12), which underlie the X chromosome-linked form and an autosomal dominant form of the disease, respectively. We studied a cohort of 98 unrelated Caucasian KAL patients. We identified KAL1 mutations in 14 patients, of which 7 (c.3G>A (p.M1?), g.IVS1+1G>T, c.570_571insA (p.R191fsX14), c.784G>C (p.R262P), c.958G>T (p.E320X), c.1651_1654delinsAGCT (p.P551_E552delinsSX), c.1711T>A (p.W571R)) have not been previously reported. In addition, we found FGFR1 mutations in 7 patients, namely c.303G>A (p.V102I), C.385A>C (p.D129A), c.810G>A (p.V273M), c.1093_1094delAG (p.R365fsX41), c.1561G>A (p.A520T), c.1836_1837insT (p.Y613fsX42), c.2190C>G (p.Y730X), all of which were novel mutations. In this study, unilateral renal agenesis and bimanual synkinesia were exclusively found associated with KAL1mutations, cleft palate and dental agenesia with FGFR1mutations.

DNA Mutational Analysis↗
PubMed2005

[GnRH antagonists: present and future].

Antagonists act by competitive inhibition of pituitary GnRH receptors for which they have a high affinity with a dose-dependent activity. The inhibition concerns LH but also FSH by inhibiting their secretion for 24 hours. At this time, only three molecules are available. Cetrorelix is mainly used for in vitro fertilization protocols, but research is currently being carried out in benign prostatic hypertrophy. Ganirelix is only used in medically assisted procreation. Abarelix is used in the United States as a monthly "depot" injection for the treatment of prostate cancer resistant to other therapies. Other molecules including orally active antagonists are in the course of clinical evaluation or in preclinical phases. The development of this therapeutic class is hampered by conflicting industrial interests and also by problems of tolerability in particular because of the side effects due to induced histamine release. The current indications in France are therefore limited to Assisted Reproductive Technology, and, recently, prostate cancer pending comparative studies versus agonists. The indications under development are endometriosis, myoma and precocious puberty, fields in which agonists have already been found to be effective. Male contraception seems to have a future however this therapeutic regimen remains very expensive. Finally, in benign prostatic hypertrophy, the antagonists administrated intermittently may be used to rapidly improve urinary flow.

Dose-Response Relationship, Drug↗
PubMed2005

Premature ovarian failure and forkhead transcription factor FOXL2: blepharophimosis-ptosis-epicanthus inversus syndrome and ovarian dysfunction.

Recently the molecular basis of the blepharophimosis-ptosis-epicanthus inversus-syndrome (BPES), an autosomal dominant developmental disorder of the eyelids and ovary, was elucidated. This syndromic form of premature ovarian failure (POF) is caused by mutations in the gene encoding the forkhead transcription factor FOXL2. In this manuscript we review the clinical features of BPES, its molecular basis, the structural and functional characteristics of the FOXL2 gene and protein, and known animal models.

Animals↗
PubMed2004

Serum antimüllerian hormone/müllerian-inhibiting substance appears to be a more discriminatory marker of assisted reproductive technology outcome than follicle-stimulating hormone, inhibin B, or estradiol.

OBJECTIVE: To test the hypothesis that the concentration of early follicular phase serum antimullerian hormone (AMH) or mullerian-inhibiting substance (MIS) is a useful marker of ovarian response and assisted reproductive technology (ART) outcome. DESIGN: Retrospective analysis of day 3 serum samples drawn before treatment. SETTING: Private ART program. PATIENT(S): One hundred nine consecutive serum samples from women younger than 42 years of age who were undergoing ovulation induction for IVF. INTERVENTION(S): Follicular aspiration for IVF after ovarian stimulation with FSH in a down-regulated cycle using GnRH-a treatment. MAIN OUTCOME MEASURE(S): Correlations between day 3 serum AMH/MIS, E2, FSH, inhibin B levels, and IVF outcome (i.e., number of retrieved mature oocytes, number and quality of embryos obtained, ongoing clinical pregnancy rates). Multivariate regression analysis on categorical data was performed to describe a predictive model of clinical pregnancy outcome. RESULT(S): Mean serum AMH/MIS value for clinical pregnancy (n = 38) was 2.4 ng/mL, in comparison to 1.1 ng/mL for those who did not become pregnant (n = 71). No differences were noted in mean values for day 3 FSH, inhibin B, or E2 between groups. Multivariate regression analysis demonstrated that day 3 serum AMH/MIS had the greatest independent contribution in predicting pregnancy outcomes. CONCLUSION(S): These data demonstrate a strong association between day 3 serum AMH/MIS level and IVF outcome in women younger than 42 years of age. Higher AMH/MIS concentrations are associated with a greater number of mature oocytes, a greater number of embryos, and ultimately a higher clinical pregnancy rate. Furthermore, AMH/MIS may offer greater prognostic value than other currently available serum markers of ART outcome.

Adult↗
PubMed2003

Loss-of-function mutations in FGFR1 cause autosomal dominant Kallmann syndrome.

We took advantage of overlapping interstitial deletions at chromosome 8p11-p12 in two individuals with contiguous gene syndromes and defined an interval of roughly 540 kb associated with a dominant form of Kallmann syndrome, KAL2. We establish here that loss-of-function mutations in FGFR1 underlie KAL2 whereas a gain-of-function mutation in FGFR1 has been shown to cause a form of craniosynostosis. Moreover, we suggest that the KAL1 gene product, the extracellular matrix protein anosmin-1, is involved in FGF signaling and propose that the gender difference in anosmin-1 dosage (because KAL1 partially escapes X inactivation) explains the higher prevalence of the disease in males.

Cell Adhesion Molecules↗
PubMed2002

Prediction of the individual follicle-stimulating hormone threshold for gonadotropin induction of ovulation in normogonadotropic anovulatory infertility: an approach to increase safety and efficiency.

OBJECTIVE: To predict the FSH response (threshold) dose in normogonadotropic, anovulatory infertile women undergoing gonadotropin induction of ovulation. DESIGN: Prospective longitudinal clinical study. SETTING: Specialist academic fertility unit. PATIENT(S): Normogonadotropic, oligoamenorrheic, infertile women who were resistant to clomiphene citrate or in whom clomiphene citrate therapy had failed. INTERVENTION(S): Daily exogenous FSH administration in a low-dose, step-up regimen. MAIN OUTCOME MEASURE(S): The FSH dose on the day of ovarian response (follicle growth > 10 mm in diameter). RESULT(S): Multivariate analysis was used to devise the following equation to predict the individual FSH response dose (75 to >187 IU/d) before initiation of therapy: [4 body mass index (in kg/m(2))] + [32 clomiphene citrate resistance (yes = 1 or no = 0)] + [7 initial free insulin-like growth factor-I (in ng/mL)] + [6 initial serum FSH level (in IU/L)] - 51. The SE of the predicted dose is 35 IU. CONCLUSION(S): The individual FSH response dose for gonadotropin induction of ovulation in anovulatory infertile women can be predicted on the basis of initial screening characteristics. The prediction model developed in this study may increase the safety and efficiency of low-dose gonadotropin protocols (step-up and step-down) by correctly determining the appropriate starting dose for a given patient.

Adult↗
PubMed2002

[Ovary genes and molecular pathology].

In the ovary, primordial follicles have to pass different stages in order to become preovulatory follicles. In the past few years, new genes and therefore new proteins have been recognized as major players in folliculogenesis. Atm, kit ligand and its receptor c-kit are necessary for the maintenance of ovarian follicle pool. GDF-9, BMP15, originating from the oocyte play a major role in early folliculogenesis. Pro and antiapoptotic proteins such as Bax and Bcl2 complete in granulosa cells, in order to maintain or not the follicle alive. FSH receptor is necessary for final follicular maturation, from the preantral stage and beyond. LH receptor is necessary for follicle ovulation. However, new genes and their regulation need to be identified as many ovarian diseases such as premature ovarian failure are not yet clarified.

Animals↗
PubMedDate not supplied

Alternative approaches in IVF.

Various new developments in clinical and basic science which may impact on IVF in the near or distant future will be discussed in this review. These key areas include the regulation of early follicle development and the extended in-vitro culture of oocytes and embryos. Moreover, alternative compounds and ovarian stimulation protocols will be discussed, along with highlights in the development of the cryopreservation of excess oocytes or embryos. Finally, the health economics of IVF is addressed.

Cells, Cultured↗