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Biomedical subjects

M Maury

Publications and source records attributed to M Maury.

At least 19 recordsLinked to original sources
PubMed2005

Manduca sexta allatotropin and the in vitro biosynthesis of juvenile hormone by moth corpora allata: a comparison of Pseudaletia unipuncta females from two natural populations and two selected lines.

We compared the effects of Manduca sexta allatotropin (Manse-AT) on the rate of in vitro juvenile hormone (JH) biosynthesis by the corpora allata (CA) of different-aged virgin females from migrant (Quebec) and non-migrant (Azores) populations of the armyworm, Pseudaletia unipuncta, as well as from early- and late-calling lines selected from the Quebec population. There was a significant age x strain interaction, with the observed rates of JH biosynthesis in early adult life closely reflecting strain-specific differences in the age at onset of calling. In considering data for all ages combined, treatment of CA with Manse-AT resulted in a significant increase in the rate of JH biosynthesis for all but the Late strain, although significant differences for this strain were detected at certain ages. The CA of females from the Azores strain showed the strongest stimulation, with those of 0- and 1-day-old individuals displaying a singularly high degree of sensitivity. Selection for early- and late-calling lines resulted in significant differences in the temporal patterns of JH biosynthesis but did not markedly affect the sensitivity of the CA to Manse-AT. These findings are discussed within the context of the age-related differences observed in the rates of in vitro JH biosynthesis and JH haemolymph titers previously reported in comparisons of the Quebec and Azorean strains of the true armyworm.

Animal Migration↗
PubMed2002

Social stigma: a comparative qualitative study of integrated and vertical care approaches to leprosy.

Integration of leprosy into the general health system is very much emphasized by health care planners. One prime reason stated for this is to reduce stigma attached to this disease. This study was conducted in the state of Maharashtra, India, to compare the level of social stigma towards leprosy in communities with a vertical and an integrated programme. The data were collected in three areas of five villages each. The first two areas were in an integrated programme to test for internal consistency and the third in a vertical programme. All the leprosy patients with visible deformities in these villages were enrolled in the study, and an in-depth stigma measurement scale was administered. In addition, focus group discussions were conducted among the family members of leprosy patients and participative rural appraisal was done in the communities. The data were analysed using qualitative methods. A total of 24 leprosy patients with visible deformities participated in the in-depth stigma measurement exercise from 15 villages. Fifteen focus group discussions were conducted with families of leprosy patients and an equal number of participatory rural appraisals with communities were done. The results show that social stigma was virtually non-existent among the communities with the integrated approach and minimally experienced by leprosy patients in this model. However, a high level of self-stigmatization among leprosy patients was observed in the vertical approach and equally a high level of social stigma was found in their communities, which led to reduced interaction between the leprosy patients and their communities. The integrated approach to community-based primary health care is effective in reducing leprosy stigma in society.

Attitude to Health↗
PubMed1998

Structure and expression of Wnt13, a novel mouse Wnt2 related gene.

We have identified a novel mouse member of the Wnt family, Wnt13. Among mouse Wnt genes, Wnt13 is most closely related to Wnt2. Sequence comparisons and chromosomal localization strongly suggest that Wnt13, rather than Wnt2, is the mouse orthologue of both the human WNT13 and Xenopus XWnt2 genes. Wnt13 is expressed in the embryonic mesoderm during gastrulation. At later stages, transcripts are detected in the dorsal midline of the diencephalon and mesencephalon, the heart primordia, the periphery of the lung bud and the otic and optic vesicles. These data suggest that Wnt13 function might partially overlap with those of other Wnt genes in the cell signaling mechanisms controlling mesoderm specification during gastrulation and some aspects of brain, heart and lung formation.

Amino Acid Sequence↗
PubMed1998

About orthostatic hypotension in tetraplegic individuals reflections and experience.

The author recalls the role of the autonomic nervous system and the means of investigation of this system in orthostatic hypotension occurring in tetraplegic individuals and the haemodynamic, biochemical and humoral changes which are triggered by upward tilting of such people. He then considers some of the problems that a person who is tetraplegic may encounter during his life. Regular follow up of each tetraplegic person is necessary and includes respiratory function tests as well as 24 h blood pressure monitoring.

Humans↗
PubMed1998

The Tetrafigap Survey on the long-term outcome of tetraplegic spinal cord injured individuals: Part I. Protocol and methodology.

The Tetrafigap Survey, a multicentre epidemiological survey on the outcome of tetraplegic spinal cord injured (TSCI) people from their first admission to a Rehabilitation Department or Centre is currently being undertaken in France. The general objective of this survey is to evaluate the situation of the TSCI people and their conditions of life in its medical, psychological and social aspects. This first article is aimed at presenting the protocol and the methodology of this survey. In a second part, yet to be submitted for publication, the preliminary results will be presented. It was first necessary to create a database of the population of TSCI people known to the centres and medical rehabilitation services, removing double entries. The criteria used for inclusion in the study were: a complete or incomplete traumatic cervical cord lesion, including post-surgical complications; age 16 or over at the time of the accident which must have occurred before December 31, 1992. The enquiry consisted of a self-administered questionnaire carried out with surviving tetraplegic people who had given their informed consent for their participation. The questionnaire consecutively covered the following topics: the situation at the time of the accident, the medical evolution between the accident and the end of stay in a rehabilitation unit, their evolution after discharge and the current situation (medical, social, professional and personal). During this first phase, 6082 TSCI people were identified by the collaborating centres. The 603 files of those who had died and 769 double entries were removed. Thus, 4710 questionnaires were sent out. The results of the participation show that 2251 people gave their consent and received questionnaires (340 additional deaths were acknowledged at this step). 163 refused, 869 were lost for follow-up, and 67 were excluded. There was no reply from 1020 people. We received 1830 questionnaires of which 1669 fulfilled all the necessary criteria for data exploitation. Home interviews with people who gave their consent will be carried out in a second phase as well as a study of deaths. A 5-year longitudinal follow-up is scheduled.

Data Collection↗
PubMed1998

Increased apoptosis of motoneurons and altered somatotopic maps in the brachial spinal cord of Hoxc-8-deficient mice.

Mice deficient for the homeotic gene Hoxc-8 suffer from a congenital prehension deficiency of the forepaw. During embryogenesis, Hoxc-8 is highly expressed in motoneurons within spinal cord segments C7 to T1. These motoneurons innervate forelimb distal muscles that move the forepaw. In Hoxc-8 mutant embryos, formation of these muscles is normal, but their innervation is perturbed. From E13.5 onwards, distal muscles normally supplied by C(7-8) MNs also receive ectopic projections from C(5-6) and T1 motoneurons. Coordinates of motor pools are altered along the rostrocaudal and also the mediolateral axes. Following this aberrant connectivity pattern and during the time of naturally occurring cell death, apoptosis is specifically enhanced in C7-T1 motoneurons. Loss of Hox-encoded regional specifications subsequently leads to a numerical deficit of motoneurons and an irreversible disorganization of motor pools. In Hoxc-8 null mutants, C(7-8) motoneurons lose their selective advantage in growth cone pathfinding behavior and/or target recognition, two essential steps in the establishment and maintenance of a functional nervous system.

Animals↗
PubMed1997

Construction of hybrid proteins that migrate retrogradely and transynaptically into the central nervous system.

The nontoxic proteolytic C fragment of tetanus toxin (TTC peptide) has the same ability to bind nerve cells and be retrogradely transported through a synapse as the native toxin. We have investigated its potential use as an in vivo neurotropic carrier. In this work we show that a hybrid protein encoded by the lacZ-TTC gene fusion retains the biological functions of both proteins in vivo-i.e. , retrograde transynaptic transport of the TTC fragment and beta-galactosidase enzymatic activity. After intramuscular injection, enzymatic activity could be detected in motoneurons and connected neurons of the brainstem areas. This strategy could be used to deliver a biological activity to neurons from the periphery to the central nervous system. Such a hybrid protein could also be used to map synaptic connections between neural cells.

Animals↗
PubMed1995

Forebrain and midbrain regions are deleted in Otx2-/- mutants due to a defective anterior neuroectoderm specification during gastrulation.

We have replaced part of the mouse homeogene Otx2 coding region with the E. coli lacZ coding sequence, thus creating a null allele of Otx2. By 9.5 dpc, homozygous mutant embryos are characterized by the absence of forebrain and midbrain regions. From the early to midstreak stages, endomesodermal cells expressing lacZ fail to be properly localized anteriorly. In the ectodermal layer, lacZ transcription is progressively extinguished, being barely detectable by the late streak stage. These data suggest that Otx2 expression in endomesoderm and ectoderm is required for anterior neuroectoderm specification. In gastrulating heterozygous embryos, a post-transcriptional repression acts on lacZ transcripts in the ectoderm, but not in the external layer, suggesting that different post-transcriptional mechanisms control Otx2 expression in both layers.

Animals↗
PubMed1994

Developmental control of IFN-alpha expression in murine embryos.

The expression of IFN-alpha transcripts was investigated in murine embryos, fetuses, and fetal annexes in mid and late pregnancy. We have shown by Northern blot analysis, reverse transcription-polymerase chain reaction, and in situ hybridization the presence of IFN-alpha transcripts in mouse placenta, fetus, and newborn. From the 14th day of gestation until birth, a typical IFN-alpha transcript (1.2 kb) is found in the fetus. A transcript of larger size (2.2 kb) appears near birth and is present in the newborn mouse. Fetal annexes between the 10th and 21st days of gestation also express IFN-alpha. From the 10th day until birth, the 1.2-kb IFN-alpha mRNA species is present, as well as unusually large transcripts: 4 and 7 kb. To localize IFN-alpha transcripts, in situ hybridization was performed, using 35S-IFN-alpha antisense RNA probe in comparison with the sense RNA probe. The tissue pattern of IFN-alpha transcription in fetuses shows a clear labeling of many epithelia, such as skin, ependyme, and intestine glandular epithelium. A possible relation with cellular differentiation is discussed.

Animals↗
PubMed1993

[Ventral and posterior expression of the homeo box gene eve1 in zebrafish (Brachydanio rerio) is repressed in dorsalized embryos].

We have identified and characterized the zebrafish eve1 homeo box gene, a member of the Drosophila even-skipped (eve) gene family. eve1 is expressed in the most posterior part of the tail bud during somitogenesis. During gastrulation, transcripts are confined to ventral and lateral cells of the marginal zone of the embryo. We show that LiCl, known to dorsalize Xenopus embryos, has the same effect in zebrafish embryos. In LiCl-treated embryos, eve1 transcripts are completely absent, suggesting that eve1 marks the ventral specification of mesoderm in zebrafish gastrulae.

Animals↗
PubMed1993

Altering the spatial determinations in the mouse embryos by manipulating the Hox genes.

Developmental genetics in Drosophila led to the isolation of the homeotic genes which are involved in the cellular positional information. In vertebrates, homologous genes have been characterized and play similar roles in the spatial determination. However, the subtle mechanisms by which positional identity is specified by the Hox genes co-expression are little known. The Hoxc-8 null mutation can induce homeosis at the anterior margin of Hoxc-8 expression, where the mosaicism observed suggests that, at least in the segmented paraxial mesoderm, the number of cells expressing a Hox gene is a determinant parameter. A combinatorial model is also suggested by several genetic experiments where the level of Hox genes expression is modified. Expression of some related Hox genes in Hoxc-8 homozygous mutants is not altered, suggesting the absence of genetic interregulations between these genes.

Animals↗
PubMed1992

Expression of a zebrafish caudal homeobox gene correlates with the establishment of posterior cell lineages at gastrulation.

This paper deals with the first identification of a caudal cDNA containing a homeobox of the Drosophila caudal family in the zebrafish. A cDNA library from late gastrula stage embryos was constructed and screened with a mouse Cdx 1 homeobox probe. A 1.6 kb cDNA clone containing a homeobox related to other caudal homeoboxes was isolated and called cdx[Zf-cad1]. Analysis of the predicted 301 amino acid translation product reveals additional regions of homology outside the homeodomain with other members of the caudal family. Particularly, the cdx[Zf-cad1] putative protein shares a conserved N-terminal region with its chicken homolog CHox-cad. Transcripts are first detected just before the onset of gastrulation. At the beginning of gastrulation, a single 1.8 kb cdx[Zf-cad1] transcript is located near the blastoderm margin with a high level of expression restricted to the epiblast. At this stage, the hypoblast is clearly negative. At the end of gastrulation, cdx[Zf-cad1] is widely expressed in vegetal (i.e. prospective posterior) epiblast and hypoblast, with a somewhat weaker expression in the dorsal hypoblast. During somitogenesis, cdx[Zf-cad1] exhibits a posterior regionalization in the neurectoderm. In contrast, no expression is detected in the mesoderm of 22 h embryos (late somitogenesis). Posterior endoderm is also positive at this stage. cdx[Zf-cad1] transcripts cease to be detected about 48 h after fertilization. They are undetectable in the adult, particularly in female gonads. The pattern of cdx[Zf-cad1] expression during and after gastrulation is consistent with its possible involvement in the regionalization of the embryo at these stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Expression patterns of vHNF1 and HNF1 homeoproteins in early postimplantation embryos suggest distinct and sequential developmental roles.

The homeoproteins HNF1 (LFB1/HNF1-A) and vHNF1 (LFB3/HNF1 beta) interact with an essential control element of a group of liver-specific genes. During development, these putative target genes are initially expressed in the visceral endoderm of the yolk sac and subsequently in fetal liver. To assess the possible involvement of HNF1 and/or vHNF1 as transcriptional regulators in the early steps of visceral endoderm differentiation, we have analyzed the expression pattern of both factors both in vitro during differentiation of murine F9 embryonal carcinoma cells and in vivo during early postimplantation mouse development. We show here that differentiation of F9 cells into either visceral or parietal endoderm is accompanied by a sharp induction in vHNF1 mRNA and protein. By contrast, only low levels of aberrantly sized HNF1 transcripts, but not DNA-binding protein, are found in F9 cells and its differentiated derivatives. At 6-7.5 days of gestation, high levels of vHNF1 mRNA are present in the visceral extraembryonic endoderm, which co-localize with transcripts of the transthyretin gene. HNF1 transcripts are first detected in the yolk sac roughly two embryonic days later, after the developmental onset of transcription of target genes. As development proceeds, discrepancies are observed between the level of transcripts of both vHNF1 and HNF1 and their respective nuclear binding proteins, notably in the yolk sac and embryonic kidney. In addition, we show that two alternative spliced isoforms of vHNF1 mRNA, vHNF-A and vHNF1-B, are expressed in both embryonic and adult tissues. Taken together, these data suggest that vHNF1 participates as a regulatory factor in the initial transcriptional activation of the target genes in the visceral endoderm of the yolk sac, whereas the later appearance of HNF1 could be required for maintenance of their expression. Our results also provide evidence of a posttranscriptional level of control of vHNF1 and HNF1 gene expression during development, in addition to the spatial restriction in transcription.

Animals↗
PubMed1991

Hepatic nuclear factor 1 (HNF1) shows a wider distribution than products of its known target genes in developing mouse.

Hepatic nuclear factor 1 (HNF1) is a highly diverged homeoprotein that is crucial for transcription of many liver-specific genes including albumin. In particular, a minimal promoter, consisting of an HNF1-binding-site and a TATA box, is highly active only in hepatoma cell lines. The expression of the HNF1 and albumin genes has been examined in mouse embryos by in situ hybridization. At 10.5 days of gestation, the HNF1 mRNA was detected in both the hepatic primordia and visceral endoderm of the yolk sac whereas the albumin transcript was present only in the nascent liver. At later stages of development, HNF1 was detected in liver, in the epithelial cells of most of the digestive tract and in the cortex of the kidney, whereas albumin was again found only in the liver. The presence of HNF1 protein in adult kidney was demonstrated by immunodetection in gel-retardation assays and western blot analysis. These experiments show that, even though the HNF1 homeo-protein is essential for expression of many liver-specific genes, it cannot, by itself, force high expression levels of these genes, in non-hepatic tissues.

Albumins↗
PubMed1990

[The demonstration of communication behaviors in children with early psychoses].

The authors present a research project on the ways children suffering from early psychosis communicate non-verbally. These children are studied in their regular treatment center, using a behavioral method using a set of possibilities described for a normal young child. For the three children who were studied, rather different means of non-verbal communication were highlighted, which changed and were enriched when the adult taking care of them "improved" the way his interaction with the child was organized. Our findings raise questions concerning the semiology of these conditions and it's treatment.

Adolescent↗