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Biomedical subjects

C Baudoin

Publications and source records attributed to C Baudoin.

At least 19 recordsLinked to original sources
PubMed2002

Foraging behavioural changes induced by conspecific and heterosubspecific odours in two strains of wild mice.

Mice in wild populations of the two subspecies Mus musculus domesticus and Mus musculus musculus may potentially compete for food. Because of the importance of olfaction in mice, we hypothesised that the presence of unfamiliar conspecific or heterosubspecific chemical cues could play a role in access to and use of food resources. We used an experimental design that tested this assumption with males from two strains, originated from wild populations of these subspecies, as subjects. Exploratory activity, latency of food approach, time and frequency on the food area, number of seeds eaten and foraging rate (number of seeds eaten/time on the food areax100) were compared for three different categories of odours (own, same strain and other strain odours) in both strains. In a foraging context, unfamiliar odours induced behavioural changes in male mice, especially an increase in exploratory activity from the more (same strain) to the less similar odour (different strain), and a reduction of time spent in the food area. Odour similarity related to genetic proximity in Mus and the cost-benefit ratio of an encounter are two possible explanations for the different processes involved in the treatment of odours in these two strains of mice.

Journal Article↗
PubMed2002

Reduced bone mineral density in postmenopausal women self-reporting premenopausal wrist fractures.

Postmenopausal fractures are associated with low bone mass; however, the role of low peak bone mass in young adults in determining subsequent osteoporosis suggests that premenopausal fractures may also be relevant. We therefore sought to determine whether a self-reported previous history of premenopausal wrist and nonwrist fractures could also be associated with bone density and therefore be used to predict osteoporosis. We recruited 453 volunteer women with a median age of 64 years (range 50-83 years), with no metabolic bone disease, previous femoral neck fracture, or prevalent vertebral fracture. Bone density at the femoral neck (FN) and lumbar spine (LS) was measured using a Lunar DPX-L. As expected, the 319 women who did not report any fracture had a higher T score at LS (-0.93 +/- 1.44) than the 134 women who reported a previous fracture at any site and at any age (T score -1.60 +/- 1.21, p < 0.001). The findings for the FN were similar. Compared with fracture-free women, the women who reported a first wrist fracture before menopause now had a lower LS T score (-1.77 +/- 1.20, n = 15, p < 0.05), whereas those who reported a nonwrist fracture showed no significant decrease in their LS T score (-1.26 +/- 1.00, n = 36). When both wrist and nonwrist fractures had occurred after menopause, the T score was significantly lower. Twenty percent of the fracture-free women were osteoporosis patients. After adjusting for body weight, age, hormonal replacement therapy (HRT), and hip fracture in the family, the relative risk (RR) of osteoporosis for premenopausal wrist fractures was 2.7 (95% confidence interval 1.4-4.3) vs. 1.2 (0.7-2.4) for women with premenopausal nonwrist fractures. We conclude that self-reported premenopausal wrist fractures, but no other fractures occurring before menopause, are likely to be associated with osteoporosis at 65 years of age, and therefore constitute strong grounds for screening.

Aged↗
PubMed2002

Genetic and environmental factors affect bone density variances of families of men and women with osteoporosis.

Our aim was to assess the relative impacts of genetics and environment in the families of osteoporotic patients and identify the best subgroup of patients to investigate the genes associated with osteoporosis. We recruited 36 men and 47 women with osteoporosis (probands), median age of 52 and 68 yr, and all their siblings (90) and offspring (83). The families were classified as young or old on the basis of the median age of the probands. We measured the bone mineral density at the femoral neck (FN) and lumbar spine (LS) adjusted for age and weight and standardized (Z-score). Physical activity, nutritional calcium, and alcohol and tobacco consumption were investigated. We compared the mean Z-score using linear mixed model and assessed the familial resemblance using intraclass correlation. The mean Z-scores of the families of osteoporotic patients were significantly negative at FN and LS, with no intergeneration or intergender differences. At FN, but not at LS, the mean Z-score was independently lower in the families of male probands (mean +/- SD: -0.57 +/- 0.96, female: -0.18 +/- 0.85, P = 0.012) and in young families (-0.58 +/- 0.94, old families: -0.11 +/- 0.83, P = 0.006). This suggested that the lower Z-score in the families of men with osteoporosis was related to their younger age. There was significant phenotypic resemblance among members in the families. In the families of female probands, the correlation between the probands and her siblings was weak and disappeared after adjustment on environment, and a resemblance appeared within their children (FN: r = 0.61) suggesting that different environment had masked the resemblance in this subgroup. In the families of male probands, a strong resemblance persisted after adjusting for environment, (proband-offspring at FN: r = 0.46 and within offspring at FN: r = 0.66, at LS: r = 0.61). This showed that resemblance was independent of a common measurable environment in these families of men with osteoporosis. In conclusion, mainly young osteoporotic patients, most of whom were male in our study, are affected by the genetic component.

Adult↗
PubMed2001

Alcohol consumption by non-institutionalised elderly women: the EPIDOS Study.

The prevalence of alcohol use declines with age, but studies suggest that between 2% and 4% of the elderly population have a particularly high alcohol consumption. The objective of this study was to verify or refute this finding and identify clinical or social characteristics associated with alcohol consumption. We measured alcohol consumption by autoquestionnaire in 7575 women, aged 75 or older, recruited at five centers in France. The alcohol consumption was computed taking account of the number of beer, wine or liquor (or spirits) drinks consumed per day. The mean age of the respondents was 80+/-6 y. Forty percent used some alcohol and 2.5% drank more than 30 grams per day. Smoking, good health status, higher socioeconomic status or single marital status were factors whose percentages increased significantly with increasing alcohol use. Despite the advanced age of this population, regular alcohol intake was prevalent but not heavy and abusive consumption drinking. Drinking appears to be associated with some medical or social characteristics and possibly with better health status.

Aged↗
PubMed2001

Indomethacin increases 15-PGDH mRNA expression in HL60 cells differentiated by PMA.

We previously reported an induction of 15-hydroxyprostaglandin dehydrogenase type I mRNA (15-PGDH) expression accompanied by a decrease in prostaglandin E2(PGE2) levels during cord blood monocytes differentiation into preosteoclastic cells by 1,25 dihydroxyvitamin D3 (1,25 (OH)2D3). These results suggested a role of prostaglandin (PG) enzymes in adhesion and/or differentiation of monocytes. In the present work, we studied modulation of gene expression of PG metabolism enzymes mRNAs in HL60 cells differentiated by phorbol myristate acetate (PMA) into the monocyte/macrophage lineage. We showed that adhesion of HL60 induced by PMA causes an increase of cyclooxygenase 2 (COX 2) and 15-PGDH mRNAs. When adding indomethacin, a non steroidal antiinflammatory drug known to inhibit COX activity, the cells remained attached and expressed large amounts of 15-PGDH mRNA while COX 2 mRNA expression remained unchanged. Indomethacin, in association with PMA can consequently exert a dual control on key enzymes of PGE2 metabolism without modifying adhesion of the cells.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

A comparative study of parental care between two rodent species: implications for the mating system of the mound-building mouse Mus spicilegus.

Paternal care is uncommon in mammals where males are more often involved in sexual competition than in providing care for their own offspring. However some species present some form of paternal care and, most of the time, this phenomenon is associated with a monogamous mating system. Mice of the genus Mus, such as the house mouse Mus musculus domesticus, are commonly considered to be polygamous-polygynous species. In Mus spicilegus, the mound-building mouse, previous results on female sexual preferences have suggested the existence of pair bonding more compatible with a monogamous mating system than with a polygamous one. We therefore tested the hypothesis that male M. spicilegus present a higher level of paternal care than males of the polygynous house mouse. Results showed that male M. spicilegus spent significantly more time covering the young during the first week after birth than male M. m. domesticus, particularly when the female was exploring, and retrieved stray pups significantly more frequently and more rapidly than male M. m. domesticus. There were practically no differences between the females of these two species. M. spicilegus parents also more significantly alternated their protection of the pups than M. m. domesticus parents. We discuss the evolution of paternal care in M. spicilegus in relation to monogamy.

Journal Article↗
PubMed2000

Effect of alcohol intake on bone mineral density in elderly women: The EPIDOS Study. Epidémiologie de l'Ostéoporose.

To study potential associations between alcohol consumption and bone mineral density in women aged 75 years or older, the authors analyzed 7,598 ambulatory women (mean age, 79.9 years; standard deviation, 3.8 years) recruited at five centers in France between 1992 and 1994. The current alcohol intake was assessed using a self-questionnaire. Bone mineral density was measured by dual-photon X-ray absorptiometry of the proximal femur and total body and adjusted for age, weight, and height (Z score). Compared with nonusers, women who drank 11-29 g of alcohol per day (g/day) had higher bone mineral density values at the trochanteric site (p = 0.0017). Neither 1-10 g/day nor >30 g/day users had increased bone mineral density levels. These results were unrelated to estrogen replacement therapy use, dietary calcium intake, current smoking status, usual physical activity, educational attainment, household monthly income, and general health status. Alcohol intake was not associated with bone mineral density at the femoral neck. Total body bone mineral density was lower in subjects with alcohol intakes >30 g/day (p = 0.047). Our data suggest that moderate drinking (e.g., 1-3 glasses of wine per day) is associated with an increase in trochanteric bone mineral density in elderly ambulatory women. However, higher intakes may have detrimental effects on bone mass.

Absorptiometry, Photon↗
PubMed2000

Calcitonin receptor mRNA in mononuclear leucocytes from postmenopausal women: decrease during osteoporosis and link to bone markers with specific isoform involvement.

Calcitonin inhibits bone resorption via its receptor (CTR) on osteoclasts. Two hCTR isoforms, hCTR1 and hCTR2, give proteins that differ in their structure and signaling pathways. We investigated whether specific isoforms or quantitative changes in total hCTR mRNA were associated with high bone resorption and turnover in menopause or osteoporosis. The hCTR mRNA in mononuclear blood cells of premenopausal (PreM), healthy (PostM), and osteoporotic (OsteoP) postmenopausal women was assessed using reverse-transcriptase polymerase chain reaction. hCTR1 and hCTR2 were investigated for 59 total RNA samples, and semiquantitative analysis of total hCTR mRNA was performed for 71. Serum calcitonin, free urinary deoxypyridinoline (D-Pyr), serum bone alkaline phosphatase (SBAP), and osteocalcin (SOC) were also evaluated. Serum calcitonin levels did not differ in PostM and OsteoP. The prevalence of each isoform was similar in the three groups. Healthy postmenopausal women and OsteoP with hCTR2 had lower bone turnover (D-Pyr: 6.79 +/- 0.54, n = 25; SBAP: 11.63 +/- 1.47, n = 26; SOC: 8.31 +/- 0.58, n = 26) than those without hCTR2 (D-Pyr: 9.90 +/- 1.95, n = 5; SBAP: 21 +/- 5.19, n = 5; SOC: 11.9 +/- 2.10, n = 5; p < 0.05). Total hCTR mRNA levels were not different in PreM and PostM. By contrast, values were strikingly lower in OsteoP (0.57 +/- 0.17, n = 28) than in PostM (2. 25 +/- 0.61, n = 19, p < 0.05) and negatively correlated with bone markers values in both. We suggest that a specific isoform and amounts of total hCTR mRNA are linked to increased bone resorption in postmenopausal osteoporosis.

Adult↗
PubMed2000

Defects in adhesion and migration, but not in proliferation and differentiation, of embryonic stem cells upon replacement of integrin subunit beta1A by beta1D.

Beta1D is a skeletal muscle-specific splice variant of the beta1 integrin subunit, while beta1A integrin subunit has a wide tissue distribution. We have previously shown that replacement of beta1A by beta1D by homologous recombination (knockin) in all mouse tissues was embryonic lethal. Through two successive rounds of homologous recombination, we have now produced embryonic stem (ES) cells expressing beta1D instead of beta1A, and analyzed the ability of beta1D to support ES cell differentiation in vitro and in teratomas in vivo. Beta1D knockin (KI) ES cells grew at a similar rate but as more compact colonies than the beta1A-expressing cells. Increased cell cohesiveness, however, did not appear to involve changes in cadherin activity. Although in both beta1A and beta1D-KI ES cells only one beta1 allele is active; the expression of beta1 integrins in the beta1D-KI ES cells was reduced by 50%, compared with that in the beta1A-expressing cells; this correlated with impaired adhesive and migratory capacities. It appeared that during in vitro cardiac differentiation, in spite of a slight delay in the induction of two cardiac-specific transcripts, the alpha- and beta-myosin heavy chains, contracting cardiomyocytes were detected in similar numbers and at the same time in embryoid bodies (EB) derived from beta1D-KI and from beta1A cells. Furthermore, replacement of beta1A by beta1D in ES cells did not affect neurite differentiation in embryoid bodies in the presence of retinoic acid suggesting that beta1D supports neurogenesis. However, the impaired migration of other cells from the EB, including endodermal cells, prevented the normal outgrowth of neurites in beta1D-KI EB. Finally, injection of beta1D-KI ES cells in the flank of syngeneic mice gave rise to fully developed teratomas containing simple and pluristratified epithelia, muscle, cartilage, blood vessels, and tissues from the neural lineage. These results show that the muscle-specific splice variant beta1D, in spite of its specific cytoplasmic domain, supports the differentiation of many cell types. This further suggests that the embryonic lethality in the beta1D-KI embryos was mainly due to the different ability of beta1 A and beta1D to mediate cell adhesion and migration.

Alternative Splicing↗
PubMed1999

Separate and combined value of bone mass and gait speed measurements in screening for hip fracture risk: results from the EPIDOS study. Epidémiologie de l'Ostéoporose.

Based on data from the EPIDOS prospective study, we have shown that femoral bone mineral density (BMD), calcaneal ultrasound measurements and fall-related factors are significant predictors of the risk of hip fracture. The goal of the present investigation, in the same cohort of elderly women, was (1) to assess and compare the value of femoral BMD, calcaneal broadband ultrasound attenuation (BUA), gait speed and age for identifying elderly women at high risk of hip fracture and (2) to determine whether combining two or more of these measurements would improve predictive ability over single measures. A total of 5895 elderly women had baseline measurements of femoral neck BMD by dual-energy X-ray absorptiometry, calcaneal BUA and gait speed. During an average of 33 months of follow-up, 170 women suffered a hip fracture. We compared the sensitivity and specificity of single and combined measures for three specific cutoff levels to define high risk, i.e., the median, the top quartile and the top decile of risk. We found that femoral BMD, calcaneal BUA, gait speed and age have approximatively the same discriminant value to identify women at high risk of hip fracture even though certain measures and combinations of measures have a significantly higher sensitivity for certain cutoff levels. The sensitivity of the available screening tools is low, even when they are combined: to obtain a sensitivity of about 80%, approximately 50% of the population must be considered to be at high risk.

Aged↗
PubMed1999

Discrimination of olfactory sexual cues in staggerer mutant male mice.

Generally, staggerer male mice do not express any preference between oestrous and anoestrous female odours in a choice test situation. The staggerer ability to discriminate between these olfactory sexual cues was evaluated in an habituation-dishabituation paradigm. In this situation it was found that the staggerer mice discriminate between these two odours. The lack of sexual odour preference in staggerer male mice is discussed through hormonal and neurological interpretation.

Animals↗
PubMed1999

Olfactory learning abilities in staggerer mutant mice.

Staggerer mutant mice were compared to non-mutant mice in two olfactory learning tasks. It was found that, in spite of a delayed acquisition compared to non-mutants, staggerer mice were able to learn an olfactory habituation task. On the other hand, staggerer presented deficits in an associative olfactory task and, contrary to non-mutants, did not learn this task. Perturbations in olfactory bulbs of staggerer mice could explain their olfactory learning deficits.

Animals↗
PubMed1998

Cre-loxP-mediated inactivation of the alpha6A integrin splice variant in vivo: evidence for a specific functional role of alpha6A in lymphocyte migration but not in heart development.

Two splice variants of the alpha6 integrin subunit, alpha6A and alpha6B, with different cytoplasmic domains, have previously been described. While alpha6B is expressed throughout the development of the mouse, the expression of alpha6A begins at 8.5 days post coitum and is initially restricted to the myocardium. Later in ontogeny, alpha6A is found in various epithelia and in certain cells of the immune system. In this study, we have investigated the function of alpha6A in vivo by generating knockout mice deficient for this splice variant. The Cre- loxP system of the bacteriophage P1 was used to specifically remove the exon encoding the cytoplasmic domain of alpha6A in embryonic stem cells, and the deletion resulted in the expression of alpha6B in all tissues that normally express alpha6A. We show that alpha6A-/- mice develop normally and are fertile. The substitution of alpha6A by alpha6B does not impair the development and function of the heart, hemidesmosome formation in the epidermis, or keratinocyte migration. Furthermore, T cells differentiated normally in alpha6A-/- mice. However, the substitution of alpha6A by alpha6B leads to a decrease in the migration of lymphocytes through laminin-coated Transwell filters and to a reduction of the number of T cells isolated from the peripheral and mesenteric lymph nodes. Lymphocyte homing to the lymph nodes, which involves various types of integrin-ligand interactions, was not affected in the alpha6A knockout mice, indicating that the reduced number of lymph node cells could not be directly attributed to defects in lymphocyte trafficking. Nevertheless, the expression of alpha6A might be necessary for optimal lymphocyte migration on laminin in certain pathological conditions.

Alternative Splicing↗
PubMed1998

Knockout and knockin of the beta1 exon D define distinct roles for integrin splice variants in heart function and embryonic development.

The beta1D integrin is a recently characterized isoform of the beta1 subunit that is specifically expressed in heart and skeletal muscle. In this study we have assessed the function of the beta1D integrin splice variant in mice by generating, for the first time, Cre-mediated exon-specific knockout and knockin strains for this splice variant. We show that removal of the exon for beta1D leads to a mildly disturbed heart phenotype, whereas replacement of beta1A by beta1D results in embryonic lethality with a plethora of developmental defects, in part caused by the abnormal migration of neuroepithelial cells. Our data demonstrate that the splice variants A and D are not functionally equivalent. We propose that beta1D is less efficient than beta1A in mediating the signaling that regulates cell motility and responses of the cells to mechanical stress.

Animals↗
PubMed1998

Effects of intraseptal infusions of N-methyl-D-aspartate receptor ligands on memory in an object recognition task in rats.

The present study describes the effects of intraseptal microinjections of N-methyl-D-aspartate (NMDA) or AP5, an agonist and an antagonist of the NMDA receptors, respectively, upon memory of rats. Animals were injected with the drug or vehicle immediately after the first exposure to two identical objects, and the duration of exploration of the familiar and a new object were evaluated 45 min or 24 h later. Vehicle-treated rats explored the new object longer than the familiar object when the intertrial time was 45 min, indicating that they remembered the familiar object, but not when the intertrial time was 24 h. The difference of exploration time between the objects was increased by NMDA, but not by AP5, when the intertrial time was 24 h, and decreased by AP5 when the intertrial interval was 45 min. These results suggest that NMDA and AP5 improves and disrupts, respectively, the consolidation in a working memory task.

2-Amino-5-phosphonovalerate↗
PubMed1998

Olfactory preferences in two strains of wild mice, Mus musculus musculus and Mus musculus domesticus, and their hybrids.

We studied olfactory preferences of two strains of mice, Mus musculus musculus and Mus musculus domesticus (considered here to be subspecies), and their hybrids, to examine the possible role of odours as a behavioural, premating mechanism that could explain the characteristics of their natural hybrid zone. We used a choice test with the bedding material of animals of the opposite sex from the animal tested and from both subspecies. Male and female M. m. domesticus showed no preference either for their own subspecies' odours or for the other subspecies' odours. In contrast, M. m. musculus individuals and three types of hybrids (all the female hybrids and males from crosses between an M. m. musculus female and an M. m. domesticus male) sniffed for longer at materials from the musculus source than from the domesticus source. We interpreted the results as a preference for musculus odours. Differences between the two subspecies in their response towards consubspecific and heterosubspecific odours could explain the asymmetrical introgression observed in the hybrid zone.Copyright 1998 The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1998

Female sexual preferences differ in Mus spicilegus and Mus musculus domesticus: the role of familiarization and sexual experience.

Mating systems correspond to particular ecological conditions and result from proximate interactions between individuals. We compared the mating preferences of female mice of two species: the house mouse, Mus musculus domesticus, and the mound-builder mouse, Mus spicilegus. Because of differences in their habitat, we expected to observe differences in their sexual preferences. We studied female preferences for a familiar or an unfamiliar male and the occurrence of copulation with the unfamiliar male, during two states of female sexual activity: (1) the postpartum oestrus of paired females, to evaluate the stability of their sexual partnership; and (2) the oestrus of females familiarized with a male, to study the mechanisms underlying their sexual preferences. In the polygamous house mouse, postpartum oestrous females did not show a clear preference between their familiar male and the unfamiliar one. Moreover, oestrous females, familiarized with a male (without sexual interactions), preferred an unfamiliar male and copulated with him. In contrast, postpartum oestrous females and oestrous females of M. spicilegus preferred their familiar male and rarely copulated with the unfamiliar male. This study indicates a strong pair bond in established breeding pairs in M. spicilegus and shows that this bond can be established by familiarization, which is not the case in M. m. domesticus. Our study suggests the existence of monogamous traits in M. spicilegus in contrast to the polygamous M. m. domesticus. (c) 1998 The Association for the Study of Animal Behaviour.

Journal Article↗