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Biomedical subjects

C Baudoin

Publications and source records attributed to C Baudoin.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1998

Bone mass in middle-aged osteoporotic men and their relatives: familial effect.

Severe idiopathic osteoporosis in middle-aged men is still poorly understood. The aim of this study was to assess the contribution of genetic factors in these patients. We studied 38 men (mean age +/- SD, 50 +/- 11 years) presenting with vertebral or peripheral bone fractures due to primary osteoporosis and 73 of their relatives divided into four subgroups: 19 brothers, 22 sisters, 13 sons, and 19 daughters. The control group comprised 199 age-matched subjects. In all subjects, we measured bone mineral density (BMD) and calculated the Z score at the lumbar spine (LS) and femoral neck (FN) based on the fitted BMD value in the controls. LS BMD values were lower in each of the four subgroups compared with the age-matched controls. The mean Z score for the overall group of 73 relatives was decreased compared with the age-matched controls (-1. 28 +/- 1.48 at the LS and -1.03 +/- 1.19 at the FN) and was not influenced by gender or by whether the relatives were siblings or children. An LS Z score < -1) was found in 54.8% of the relatives of osteoporotic patients versus 17.4% of the control subjects (risk ratio, 3.2). Alcohol and tobacco abuse are well-known risk factors for osteoporosis in men. Among the 38 osteoporotic patients, 7 were heavy smokers (>20 pack-years), 8 were both heavy smokers and drinkers (>80 g/day for at least 10 years and gammaGT > 40 UI/l), and 23 had neither of these risk factors. BMD, Z score, and anthropometric data were the same in patients with and without risk factors. Decreases in LS and FN Z scores were similar in relatives of patients with and without risk factors. In conclusion, low BMD is observed in relatives of osteoporotic men with or without risk factors for osteoporosis, indicating that familial factors contribute to primary osteoporosis in middle-aged men.

Absorptiometry, Photon↗
PubMed1997

Early behavioral development of mice is affected by staggerer mutation as soon as postnatal day three.

Staggerer is a neurological mutation of mice that affects the development of the central nervous system and causes abnormal behaviors. The staggerer cerebellum is already abnormal at birth and as the animal grows up there is a progressive loss of granule cells which have all disappeared by day 28. The earliest behavioral disturbance observed is a motor deficiency which occurs between 10 and 15 days-i.e. several days later than the appearance of the cortical abnormalities. To show that staggerer mutant mice also differ from normal mice in behavioral aspects before the age of 10 days, 28 staggerer pups and 246 normal pups aged from 1 to 9 days underwent different motor tests. In addition, the number of ultrasounds emitted during 40 s was recorded, and the animals were weighted every day. Differences between staggerer and normal mice were found as early as 3 days: staggerers were less efficient in motor tasks and they weighed less than normal mice. Staggerers also differed from normal mice in ultrasound production.

Animals↗
PubMed1997

Spatial and temporal expression of the beta1D integrin during mouse development.

The beta1D protein is a recently characterized isoform of the integrin beta1 subunit that is present in cardiac and skeletal muscles. In this study, we have examined the expression of beta1D in different types of skeletal muscle and in cardiac muscle and studied its distribution during mouse development, using new monoclonal antibodies specific for beta1D. Immunoprecipitation studies revealed that, while beta1A is strongly expressed in proliferating C2C12 myoblasts, beta1D is only expressed after their differentiation to myotubes. In these myotubes, beta1D is associated with different alpha subunits, namely alpha3A, alpha5, alpha7A, or alpha7B. Initially, during embryogenesis, the alpha1A subunit is the only beta1 variant expressed in skeletal and cardiac muscle. The beta1D subunit is first detected in skeletal muscle at E17.5, whereas in cardiac muscle its expression begins around the time of birth. Later the expression of beta1A in skeletal and cardiac muscle becomes restricted to capillary cells, whereas beta1D eventually becomes the only variant expressed in adult cardiac and skeletal muscle cells. The switch from the beta1A to the beta1D subunit in cardiac muscle cells coincides with the expression of alpha7. In adults there is a distinct concentration of beta1D at the myotendinous junctions of muscle fibers and at costameres in both cardiac and skeletal muscle. In addition, beta1D is present at intercalated discs in cardiac muscle and at neuromuscular junctions in skeletal muscle cells. The amount of beta1D in different types of skeletal muscle (fast, slow, and mixed-type) was similar, but cardiac muscle expressed almost five times as much of this protein. We suggest that beta1D plays a role in the maintenance of the cytoarchitecture of mature muscle and in the functional integrity of the muscle cells.

Animals↗
PubMed1997

Hyposmia for butanol and vanillin in mutant staggerer male mice.

To address the hypothesis that reproductive deficits in male house mice expressing the staggerer mutation are due to chemosensory deficits, we examined behavioral responses to odorants. Two-choice tests (butanol or vanillin vs. amyl acetate odors) were used to determine behavioral thresholds for butanol, an aversive odor, and for vanillin, an attractive odor. Two groups of C57B1/6 male mice (one nonmutant group and one mutant group) were studied using an olfactometer. Different concentrations of butanol were used: from 5.5 x 10(-4) M to 5.5 x 10(-1) M. Vanillin at different concentrations, from 6.6 x 10(-5) M to 6.6 x 10(-2) M, was presented during the tests after a 1-month period of familiarization. Aversive and attractive behavioral thresholds of staggerer mice were higher than those of nonmutant mice. The staggerer mutation induces hyposmia in mice. This olfactory deficit could explain, at least partially, abnormalities in the social and sexual behaviors of staggerer mice.

Animals↗
PubMed1996

Fall-related factors and risk of hip fracture: the EPIDOS prospective study.

BACKGROUND: Most hip fractures result from falls. However, the role of fall-related factors has seldom been examined. Comparison of the predictive value of these factors with that of bone mineral density (BMD) has important implications for the prevention of hip fractures. METHODS: We assessed femoral-neck BMD by dual-photon X-ray absorptiometry and potential fall-related risk factors, which included self-reported physical capacity, neuromuscular function, mobility, visual function, and use of medication in 7575 women, aged 75 years or older, with no history of hip fracture recruited at five centres in France. We followed up these women every 4 months to record incident hip fractures. During an average of 1.9 years of follow-up 154 women suffered a first hip fracture. FINDINGS: In age-adjusted multivariate analyses, we found four independent fall-related predictors of hip fracture: slower gait speed (relative risk = 1 . 4 for 1 SD decrease [95% Cl 1.1-1.6)]; difficulty in doing a tandem (heel-to-toe) walk (1.2 for 1 point on the difficulty score [1.0-1.5]); reduced visual acuity (2.0 for acuity < or = 2/10 [1.1-3.7]); and small calf circumference (1.5 [1.0-2.2]). After adjustment for femoral-neck BMD, neuromuscular impairment--gait speed, tandem walk--and poor vision remained significantly associated with an increased risk of subsequent hip fracture. With high risk defined as the top quartile of risk, the rate of hip fracture among women classified as high risk based on both a high fall-risk status and low BMD was 29 per 1000 women-years, compared with 11 per 1000 for women classified as high risk by either a high fall-risk status or low BMD; for women classified as low risk based on both criteria the rate was five per 1000. INTERPRETATION: We conclude that neuromuscular and visual impairments, as well as femoral-neck BMD, are significant and independent predictors of the risk of hip fracture in elderly mobile women, and that their combined assessment improves the prediction of hip fractures.

Absorptiometry, Photon↗
PubMed1996

Dual incorporation of (35S)sulfate into dentin proteoglycans acting as mineralization promotors in rat molars and predentin proteoglycans.

Autoradiographic investigations were carried out 0.5, 1, 2, 4, 24, 48, 72, and 120 hours after the injection of a single dose of [35S]-sulfate on undemineralized molars of 7-15-day-old rats. In predentin, labeling was detected at 0.5 hours. Silver grain density reached a plateau value between 1 and 24 hours, then decreased and disappeared 120 hours after injection. In dentin, the mineralization front started to be labeled as early as 0.5 hours after injection. Labeling increased at the dentin edge between 1 and 2 hours, reached a maxima at 4 hours, then started to decrease, the labeled band seen 24 hours after injection being further incorporated into dentin. This band stood at constant distance from the dentin-enamel junction with stable grain density, even at 120 hours. This investigation proves the existence of two distinct groups of [35S]-labeled proteoglycans, one exclusively related to predentin and disappearing with time, and the second one located in dentin behaves as a stable component. The fact that an early labeling appeared at the mineralization front which was further incorporated into dentin, confirms that dentin proteoglycans constitute an individual group of molecules that are not derived from predentin proteoglycans, and act as mineralization promotors.

Animals↗
PubMed1996

Clinical outcomes and mortality after hip fracture: a 2-year follow-up study.

The aim of this study was to evaluate the burden of hip fractures, which occurred in the French region of Picardie, in 1992, among 1103 women and 356 men, whether the fractures occurred at home or in a community (i.e., patients who depended on a collective service). The data are part of the PICAROS study, which was designed to assess prospectively the outcome of patients as judged by clinical, economical, and quality of life factors. Patients and/or proxies were questioned during the 2nd or 3rd week following the fracture, and again at 3, 6, 12, and 24 months after the fracture. The survey was conducted by home interview. Recruitment criteria were: 1) all patients with a hip fracture as defined by the International Classification of Disease (ICD); 2) 20 years of age and over; 3) admitted to one of the 34 surgical units from the region, public and private, and had an operation or not. Patients with metastatic or myelomatous fractures or fractures on prothesis device were not included. For the present analysis, patients under 50 years of age were excluded. Among people aged 50 years and over, 3% of the general population lived in a community; 32% of hip fractures were from a community. Patients in a community, aged 60-69, had 15 times more risk of having a hip fracture than subjects of the same age at home. The excess risk decreased with age and stabilized over 85 years of age at two to threefold. During the 24 month follow-up, 394 women and 173 men died. Among those surviving, 87% were interviewed at 2 years. We analysed seven classes of complications, according to the ICD: (1) pressure sores and blisters; (2) pulmonary infections; (3) urinary infections; (4) surgical complications; (5) orthopedic complications; (6) thrombosis and embolisms; and (7) secondary hip fractures. Patients coming from a community had a higher risk of mortality, pressure sores, surgical complications, and pulmonary and urinary infections. From an economical perspective, the institutionalized population would seem to be a profitable target for the prevention of fractures and their complications.

Aged↗
PubMed1996

A morphometric investigation of myotube formation in rabbit embryo medial pterygoid muscle.

To determine the times of the appearance of myoblasts, early myotubes, late myotubes, and myofibers, we studied a region between two aponeuroses of the medial pterygoid masticatory muscle in embryos of two strains of rabbits, without disturbing the normal innervation. The objectives of this study were to define the quantitative relations among these cells and to determine their kinetics statistically. We used Fauve de Bourgogne and New Zealand rabbit embryos on day 17, day 17 plus 12 hours, day 18, day 18 plus 12 hours, and days 20, 22, and 28 of gestation. Cell proliferation was studied with a light microscope, by means of counting methods. Similar development was observed in the two strains of rabbits. The numbers of myoblasts decreased as follows: (i) a marked decrease; (ii) a sudden cessation of the decrease, marked by a rebound at 18 days, and lasting less than 24 hours; and (iii) a plateau between embryonic days 22 and 28. The onset of reduction in the number of early myotubes coincided with the rebound of myoblasts. The number of late myotubes increased at the time of maximal early myotube density and during rebound of the myoblasts. Myofiber densities were similar to late myotube densities on day 22. We suggest that early myotubes are formed very gradually by fusion of myoblasts, and that the significant increase in the numbers of myoblasts corresponds to the second generation of myoblasts necessary for differentiation of late myotubes.

Analysis of Variance↗
PubMed1996

Genomic organization of the mouse beta 1 gene: conservation of the beta 1D but not of the beta 1B and beta 1C integrin splice variants.

We have determined the genomic organization of the 3'-region of the murine beta 1 gene and cloned the murine beta 1D integrin splice variant. Overlapping genomic clones encompassing the region of the beta 1D-specific exons were isolated from a phage lambda FIXII library, mapped and partially sequenced. All of the exon-intron junctions identified in the murine beta 1 gene fit with the consensus splice donor and acceptor sequences and occur at the same positions as in their human counterparts. cDNA clones for the beta 1D integrin were isolated from a murine skeletal muscle library. The human and murine beta 1D sequences are conserved at the nucleotide (93%) and amino acid (100%) level, suggesting an important role of this muscle-specific variant throughout mammalian phylogenesis. In contrast, murine sequences for beta 1B are very different from human beta 1B at both the nucleotide as well as amino acid level. Moreover, no specific polyadenylation signal for the beta 1B variant could be identified in genomic clones, suggesting that this variant is not present in the mouse. Finally, we were not able to identify a murine beta 1C splice variant by sequencing analysis, Southern hybridization techniques or polymerase chain reaction of mRNA from platelets. These findings indicate that the beta 1B and beta 1C variants emerged relatively late in the phylogenesis of the beta 1 integrin family.

Animals↗
PubMed1995

Cloning of the laminin alpha 3 chain gene (LAMA3) and identification of a homozygous deletion in a patient with Herlitz junctional epidermolysis bullosa.

Laminin 5 and laminin 6 are basement membrane proteins synthesized by the basal cells of stratifying squamous epithelia. Altered expression of laminin 5 has been associated with Herlitz junctional epidermolysis bullosa (H-JEB), a severe epidermal blistering disorder inherited as an autosomal recessive disease. We have isolated cDNA clones encoding the alpha 3 chain of laminin 5 and searched for mutations in the LAMA3 gene in H-JEB patients. In one H-JEB family, an affected individual exhibited drastically reduced immunoreactivity to antibodies directed against the alpha 3 chain of laminin 5 and an impaired expression of the corresponding mRNA transcripts. RT-PCR analysis of mRNA extracted from the proband's keratinocytes identified a homozygous single basepair deletion in the transcripts encoding the laminin alpha 3A and alpha 3B isoforms. The mutation causes a frameshift and premature termination codon in both alleles of the LAMA3 gene. Inheritance of the clinical H-JEB phenotype was consistent with the segregation of the mutated allele in the family. We also report the identity of the alpha chains of laminin 5 and epiligrin and provide evidence that LAMA3 transcripts are distinct from the laminin 6 alpha chain mRNA.

3T3 Cells↗