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F Poirier

Publications and source records attributed to F Poirier.

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

Embryonic implantation in galectin 1/galectin 3 double mutant mice.

Galectin 1 and galectin 3 are first expressed in the trophectoderm cells of the implanting embryo and have been implicated in the process of implantation. However, we had previously shown that the lack of galectin 1 in galectin 1 null mutant mice is compatible with implantation. In this study, we describe the generation of galectin 3 null mutant mice and show that they are viable and have no overt abnormalities. The importance of galectin 1 and galectin 3 in implantation was assessed by obtaining double mutant mice [gal1 -/-; gal3 -/-]. We find that implantation can still occur in the absence of both galectin 1 and galectin 3. However, we show that galectin 5, a third member of this gene family, is also present in the blastocyst at the time of implantation.

Animals↗
PubMed1998

Update on metal content profiles in mushrooms--toxicological implications and tentative approach to the mechanisms of bioaccumulation.

Fifteen metals (macroelements, heavy metals and trace elements) have been investigated using inductively coupled plasma-atomic emission spectrometry (ICP-AES) on 92 specimens of mushrooms collected in France, in the Paris region. Their levels and distributions are given. Taking in account the respective contents and bioaccumulation abilities, the data reveal that different mechanisms are involved depending on fungi species and genera besides physicochemical influences. Moreover, they suggest that the different elements might accumulate through various ways that are successively mentioned. Metabolic, toxicological and environmental significances are discussed.

Agaricales↗
PubMed1998

Maintenance of granulocyte numbers during acute peritonitis is defective in galectin-3-null mutant mice.

Galectin-3, also known as the macrophage marker Mac-2, is a member of a family of structurally related animal lectins that exhibit specificity for beta-galactosides. In order to investigate the role of galectin-3 in acute inflammation, we have compared the number of leucocytes present in the peritoneal cavity of wild type and galectin-3 null mutant mice after intraperitoneal (i.p.) injection of thioglycolate broth. At day 1 after injection, we found no difference in the recruitment of mononuclear phagocytes and granulocytes to the peritoneal cavity. However, 4 days after thioglycolate injection, galectin-3 mutant mice exhibited a significantly reduced number of recoverable granulocytes compared to wild-type animals. As mutant granulocytes did not exhibit an accelerated rate of apoptosis and their uptake by macrophages appeared to be unaffected by the mutation, the phenotype described here suggests that galectin-3 participates in an additional level of control during the resolution of acute inflammation.

Acute Disease↗
PubMed1998

Teaching CAPD to the visually impaired.

The increasing number of patients on CAPD (continuous ambulatory peritoneal dialysis) offers multiple challenges to the home dialysis unit. During the last year we have changed our nursing practice and have successfully trained five visually impaired clients to perform CAPD exchanges utilizing a disconnect system without a helper or caregiver. In this article we will discuss the methods we used, the assist devices and the patient outcomes in our population. We measured our success in terms of peritonitis rate, adequacy of dialysis and lifestyle considerations for this population.

Adult↗
PubMed1997

Deletion of the H19 transcription unit reveals the existence of a putative imprinting control element.

The distal region of mouse chromosome 7 contains a cluster of imprinted genes that includes H19 and Igf2 (insulin-like growth factor 2). H19 is expressed as an untranslated RNA found at high levels in endodermal and mesodermal embryonic tissues. This gene is imprinted and exclusively expressed from the allele of maternal origin. The Igf2 gene shows a similar pattern of expression but is expressed from the paternal allele. We have generated a targeted deletion of the H19 transcription unit by insertion of a neo replacement cassette. The homozygous mutant animals are viable and fertile and display an overgrowth phenotype of 8% compared with wild-type littermates. This is associated with the disruption of Igf2 imprinting and the consequent biallelic expression of this gene. A striking feature of the recombinant H19 allele is the occurrence of a parental imprint set on the neo replacement cassette. Therefore imprinting of the H19 locus is independent of the H19 gene itself. Taken together with the results of a larger H19 mutation described previously, this indicates that an imprinting control element is located within the region 10 kb upstream of H19.

Animals↗
PubMed1997

Cell surface carbohydrates and lectins in early development.

Current knowledge on the development regulation of cell surface carbohydrates and lectins in mammalian embryos is summarized. Much of this data comes from observations on mouse embryos but information on the human embryo is included where it is available. Over the last few years, numerous studies have indicated that carbohydrates play a critical role in the cell-cell interactions of the pre- and peri-implantation embryo. Functional tests suggest a role for terminal fucosylated Galbeta1-3/4GlcNAc structures in the early steps of implantation. We also now have clear evidence for the expression of lectins in the trophectoderm just prior to implantation. Mouse mutants have been generated which lack particular enzymes involved in glycosylation or particular lectins, but so far they have not been informative about the role of glycoconjugates or lectins in the very early embryo.

Animals↗
PubMed1996

Role of galectin-1 in the developing mouse olfactory system.

Primary sensory olfactory neurons reside in a neuroepithelium lining the nasal cavity and project topographically onto the surface of the olfactory bulb, a rostral extension of the telencephalon. Galectin-1, a bivalent galactose-binding vertebrate lectin, is expressed in the developing rodent olfactory system. In the present study, the mouse olfactory neuron cell line 4.4.2 was used to examine the role of galectin-l in neurite outgrowth in vitro. Recombinant galectin-l has neurite outgrowth-promoting activity when used as a substrate for 4.4.2 cells. When either galectin-1 or lactose was added to the culture media, the neurite outgrowth-promoting activity was abolished. These results demonstrate that galectin-1 can modulate neurite growth in vitro. The in vivo role of galectin-1 was investigated by examining the topographical organization of the olfactory pathway in mice carrying a null mutation for galectin-1. Using Dolichos biflorus agglutinin as a convenient histochemical marker of a subpopulation of primary sensory olfactory neurons which project topographically to the dorsomedial olfactory bulb, we show an aberrant topography of olfactory axons in the null mutants. A subset of primary sensory olfactory axons failed to project to their correct target sites in the caudal olfactory bulb. These data indicate that galectin-1 is involved in the growth and/or guidance of primary sensory olfactory axons between the nasal cavity and the olfactory bulb. This is the first demonstration that a lectin has neurite outgrowth-promoting activity and plays a role in neuronal pathfinding in the mammalian nervous system.

Animals↗
PubMed1995

WW6: an embryonic stem cell line with an inert genetic marker that can be traced in chimeras.

Mutant mice produced by gene targeting in embryonic stem (ES) cells often have a complex or embryonic lethal phenotype. In these cases, it would be helpful to identify tissues and cell types first affected in mutant embryos by following the contribution to chimeras of ES cells homozygous for the mutant allele. Although a number of strategies for following ES cell development in vivo have been reported, each has limitations that preclude its general application. In this paper, we describe ES cell lines that can be tracked to every nucleated cell type in chimeras at all developmental stages. These lines were derived from blastocysts of mice that carry an 11-Mb beta-globin transgene on chromosome 3. The transgene is readily detected by DNA in situ hybridization, providing an inert, nuclear-localized marker whose presence is not affected by transcriptional or translational controls. The "WW" series of ES lines possess the essential features of previously described ES lines, including giving rise to a preponderance of male chimeras, all of which have to date exhibited germ-line transmission. In addition, clones selected for single or double targeting events form strong chimeras, demonstrating the feasibility of using WW6 cells to identify phenotypes associated with the creation of a null mutant.

Alleles↗
PubMed1995

Galectin-3 is expressed in the notochord, developing bones, and skin of the postimplantation mouse embryo.

The galectins are a family of low molecular weight, calcium-independent mammalian carbohydrate binding proteins that exhibit specificity for beta-galactoside derivatives. We have examined the expression pattern of galectin-3 in the developing mouse embryo by in situ hybridisation and immunohistochemistry. In the embryo proper, galectin-3 message and protein are first detected in notochord, starting from 8.5 days post coitum (dpc), and persist until this structure disappears. Galectin-3 is later found in cartilage primordia and in developing skin from 13.5 dpc. This very restricted and dynamic pattern suggests that galectin-3 may participate in the establishment and/or maintenance of notochord as well as the formation of cartilage and differentiation of skin. Finally, we find that galectin-3, which is identical to the macrophage marker Mac-2, is also expressed in embryonic macrophages.

Animals↗
PubMed1993

Specification of axial identity in the mouse: role of the Hoxa-5 (Hox1.3) gene.

Numerous lines of study have suggested that the Hox genes, encoding putative transcription factors, are key genes in the establishment of the body plan of the mammalian embryo. To examine the role of Hoxa-5 (Hox1.3) gene during development, we have used targeted mutagenesis in embryonic stem cells to produce a strain of mice carrying a disrupted Hoxa-5 allele. The viability of homozygous mutant mice is markedly reduced, with 50% of the mutant animals dying at birth or shortly thereafter. Analysis of the skeleton of Hoxa-5 mutants reveals a number of homeotic transformations restricted to the cervical and thoracic regions. Of these, one of the most frequent morphological abnormalities is the posterior transformation of the seventh cervical vertebra into the likeness of a thoracic vertebra complete with a pair of ribs. These results demonstrate that the Hoxa-5 gene has an important role in the establishment of the skeleton during development and contributes to the process whereby the axial structures are determined.

Animals↗
PubMed1993

Subcutaneous emphysema and pneumomediastinum following dental extraction.

A case of acute subcutaneous emphysema of the lateral region of the neck is described. The patient, a 26-year-old woman, also had radiologic evidence of pneumomediastinum. She completely recovered in a few days under prophylactic antibiotherapy. In this case, subcutaneous and mediastinal emphysema was most probably due to the introduction of air into the soft tissue during dental surgery using compressed air equipment.

Adult↗
PubMed1993

Normal development of mice carrying a null mutation in the gene encoding the L14 S-type lectin.

The L14 lectin is a 14 x 10(3) M(r) carbohydrate binding protein belonging to the family of S-type lectins. The pattern of expression of this protein during mouse embryogenesis suggests that it may have multiple roles during pre- and post-implantation development. Using the technique of homologous recombination in embryonic stem cells, we have introduced a null mutation in the gene encoding the L14 lectin and generated a strain of mice carrying the mutant allele. We report here that homozygous mutant animals that lack the L14 lectin develop normally and are viable and fertile. The absence of any major phenotypic abnormalities in these mutant animals suggests that other protein(s) potentially compensate for the absence of the L14 lectin. Here we show that a related protein termed L30, a lectin that has carbohydrate binding specificity similar to that of L14, is present in the same embryonic cell populations as L14 at the time of implantation, suggesting that the two S-type lectins may be capable of functional substitution at this early stage of embryogenesis.

Animals↗
PubMed1993

The gene encoding the calcium binding protein calcyclin is expressed at sites of exocytosis in the mouse.

Calcyclin is a member of the S100 family of calcium binding proteins. We have found by in situ hybridization that calcyclin transcripts are restricted to specific cell types within a limited number of mouse organs. High levels of expression in the epithelia lining the gastrointestinal, respiratory and urinary tracts, and specific localization of the transcripts to the goblet cells in the small intestine, lead us to suggest a role for calcyclin in the process of mucus secretion. In addition, calcyclin expression was detected in the corpus luteum, placenta and nerves within the gut wall, which are all sites of regulated exocytosis. We propose that this S100-like protein may be part of a calcium signalling pathway utilized in the secretion of various products by different cell types.

Age Factors↗
PubMed1992

Expression of the L14 lectin during mouse embryogenesis suggests multiple roles during pre- and post-implantation development.

A cDNA encoding L14, the lactose-binding, soluble lectin of relative molecular mass 14 x 10(3), has been isolated in a differential screen designed to identify genes that are regulated during the differentiation of murine embryonic stem cells in vitro. The expression patterns of the gene and of the encoded protein during mouse embryogenesis are consistent with the lectin playing a role at several stages of development. Firstly, it is initially synthesised in the trophectoderm of expanded blastocysts immediately prior to implantation, suggesting that it may be involved in the attachment of the embryo to the uterine epithelium. Secondly, in the postimplantation embryo, the lectin is abundantly expressed in the myotomes of the somites. This observation, when taken together with data indicating a role for the lectin in myoblast differentiation in culture, suggests that the protein is important in muscle cell differentiation. Finally, within the nervous system expression of this gene is activated early during the differentiation of a particular subset of neurones.

Animals↗
PubMed1991

The murine H19 gene is activated during embryonic stem cell differentiation in vitro and at the time of implantation in the developing embryo.

The differentiation in vitro of murine embryonic stem cells to embryoid bodies mimics events that occur in vivo shortly before and after embryonic implantation. We have used this system, together with differential cDNA cloning, to identify genes the expression of which is regulated during early embryogenesis. Here we describe the isolation of several such cDNA clones, one of which corresponds to the gene H19. This gene is activated in extraembryonic cell types at the time of implantation, suggesting that it may play a role at this stage of development, and is subsequently expressed in all of the cells of the mid-gestation embryo with the striking exception of most of those of the developing central and peripheral nervous systems. After birth, expression of this gene ceases or is dramatically reduced in all tissues.

Amino Acid Sequence↗
PubMed1990

A POU-domain transcription factor in early stem cells and germ cells of the mammalian embryo.

The murine oct-3 gene encodes a transcription factor containing a POU-specific domain and a homeodomain. In marked contrast to other homeodomain-encoding genes, oct-3 is expressed in the totipotent and pluripotent stem cells of the pregastrulation embryo and is down-regulated during differentiation to endoderm and mesoderm, suggesting that it has a role in early development. The oct-3 gene is also expressed in primordial germ cells and in the female germ line.

Amino Acid Sequence↗
PubMed1990

Transformation-defective mutants with 5' deletions of the src gene are frequently generated during replication of Rous sarcoma virus in established quail fibroblasts.

Replication of Rous sarcoma virus (RSV) in avian fibroblasts leads to the generation of replication-competent variants that are defective for cell transformation (td virus). These td variants contain deletions affecting various portions of the v-src gene. We compared the rate of td virus production in Q3B cells, a quail cell line established by mutagen treatment, and in normal quail fibroblasts. Twenty-five days after infection with an RSV stock containing only transforming virions, Q3B cells harbor similar amounts of v-src-containing and v-src-deleted proviruses. However, these cells synthesize very low levels of p60v-src and generate large excess of td variants, as determined by biological assays. Unlike Q3B cells, normal quail fibroblasts infected with the same virus stock produce td variants only after multiple passages of undiluted virus on fresh cells. Restriction analysis showed that the td virus produced by Q3B cells is composed of two types of genomes: one lacking the entire v-src gene and the other carrying partial deletions of this gene predominantly located in the amino-terminal portion of the coding region of v-src. To study the mechanisms of these partial deletions, we molecularly cloned and sequenced the v-src genes of several td proviruses. We show that these mutants carry single or multiple v-src deletions of limited size, presumably generated by multiple mechanisms. Two deletions of 170 and 112 bp located in the 5' portion of v-src are frequently generated during RSV replication in Q3B cells and may represent preferential sites for v-src deletion in these cells.

Animals↗