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1.
J Cancer Educ ; 38(3): 1091-1097, 2023 06.
Article in English | MEDLINE | ID: mdl-37009945

ABSTRACT

H igh-quality cancer care is a key priority worldwide. Caring for people affected by cancer requires a range of specific knowledge, skills and experience to deliver the complex care regimens both within the hospital and within the community environment. In June 2022, the European Cancer Organisation along with 33 European cancer societies began working together to develop a curriculum for inter-speciality training for healthcare professionals across Europe. As part of the project, this research consisted of a qualitative survey distributed to the European Union societies via email. The aim of this paper is to disseminate the qualitative findings from healthcare professionals across Europe. Questionnaires were sent out to a convenience sample of 219 healthcare professionals and patient advocates with a response rate of 55% (n = 115). The findings identified that there were four key themes: 'What is inter-speciality training?', 'Barriers and challenges', 'Support throughout the cancer journey' and 'New ways of working'. These results are part of a larger needs analysis and scoping review to inform the development of a core competency framework which will be part of an inter-speciality curriculum for specialist cancer doctors, nurses and other healthcare professionals across Europe. Healthcare professionals will be able to access education and training through the virtual learning environment and workshops and by clinical rotations to other specialties.


Subject(s)
Curriculum , Neoplasms , Humans , Health Personnel/education , Europe , Learning , Educational Status , Qualitative Research , Neoplasms/therapy
3.
Cell Mol Life Sci ; 64(6): 643-5, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17380305

ABSTRACT

Advances in our understanding of cardiac development have fuelled research into cellular approaches to myocardial repair of the damaged heart. In this collection of reviews we present recent advances into the basic mechanisms of heart development and the resident and non-resident progenitor cell populations that are currently being investigated as potential mediators of cardiac repair. Together these reviews illustrate that despite our current knowledge about how the heart is constructed, caution and much more research in this exciting field is essential. The current momentum to evaluate the potential for cardiac repair will in turn accelerate research into fundamental aspects of myocardial biology.


Subject(s)
Developmental Biology , Heart/embryology , Heart/physiology , Wound Healing , Animals , Humans , Stem Cells/cytology , Transcription Factors/metabolism
4.
Dev Cell ; 1(3): 435-40, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11702954

ABSTRACT

Development of the arterial pole of the heart is a critical step in cardiogenesis, yet its embryological origin remains obscure. We have analyzed a transgenic mouse line in which beta-galactosidase activity is observed in the embryonic right ventricle and outflow tract of the heart and in contiguous splanchnic and pharyngeal mesoderm. The nlacZ transgene has integrated upstream of the fibroblast growth factor 10 (Fgf10) gene and comparison with the expression pattern of Fgf10 in pharyngeal mesoderm indicates transgene control by Fgf10 regulatory sequences. Dil labeling shows a progressive movement of cells from the pharyngeal arch region into the growing heart tube between embryonic days 8.25 and 10.5. These data suggest that arterial pole myocardium originates outside the classical heart field.


Subject(s)
Fibroblast Growth Factors/genetics , Heart/embryology , Mesoderm/metabolism , Pharynx/embryology , Animals , Carbocyanines/metabolism , Fibroblast Growth Factor 10 , Fluorescent Dyes/metabolism , Heart/physiology , In Situ Hybridization , Mesoderm/cytology , Mice , Mice, Transgenic , Myocardium/cytology , Myocardium/metabolism , Pharynx/metabolism , Transgenes , beta-Galactosidase/genetics , beta-Galactosidase/metabolism
5.
J Cell Biol ; 151(6): 1221-34, 2000 Dec 11.
Article in English | MEDLINE | ID: mdl-11121437

ABSTRACT

Skeletal muscle is one of a several adult post-mitotic tissues that retain the capacity to regenerate. This relies on a population of quiescent precursors, termed satellite cells. Here we describe two novel markers of quiescent satellite cells: CD34, an established marker of hematopoietic stem cells, and Myf5, the earliest marker of myogenic commitment. CD34(+ve) myoblasts can be detected in proliferating C2C12 cultures. In differentiating cultures, CD34(+ve) cells do not fuse into myotubes, nor express MyoD. Using isolated myofibers as a model of synchronous precursor cell activation, we show that quiescent satellite cells express CD34. An early feature of their activation is alternate splicing followed by complete transcriptional shutdown of CD34. This data implicates CD34 in the maintenance of satellite cell quiescence. In heterozygous Myf5(nlacZ/+) mice, all CD34(+ve) satellite cells also express beta-galactosidase, a marker of activation of Myf5, showing that quiescent satellite cells are committed to myogenesis. All such cells are positive for the accepted satellite cell marker, M-cadherin. We also show that satellite cells can be identified on isolated myofibers of the myosin light chain 3F-nlacZ-2E mouse as those that do not express the transgene. The numbers of satellite cells detected in this way are significantly greater than those identified by the other three markers. We conclude that the expression of CD34, Myf5, and M-cadherin defines quiescent, committed precursors and speculate that the CD34(-ve), Myf5(-ve) minority may be involved in maintaining the lineage-committed majority.


Subject(s)
Antigens, CD34/isolation & purification , DNA-Binding Proteins , Muscle Proteins/isolation & purification , Muscle, Skeletal/cytology , Stem Cells/cytology , Trans-Activators , Animals , Cell Differentiation , Cell Lineage , Mice , Mice, Transgenic , Muscle Fibers, Skeletal/cytology , Muscle, Skeletal/embryology , Myogenic Regulatory Factor 5 , Peptide Fragments/isolation & purification , RNA, Messenger/isolation & purification , Regeneration
6.
Microsc Res Tech ; 50(6): 510-21, 2000 Sep 15.
Article in English | MEDLINE | ID: mdl-10998640

ABSTRACT

Isoform diversity in striated muscle is largely controlled at the level of transcription. In this review we will concentrate on studies concerning transcriptional regulation of the alkali myosin light chain 1F/3F gene. Uncoupled activity of the MLC1F and 3F promoters, together with complex patterns of transcription in developing skeletal and cardiac muscle, combine to make analysis of this gene particularly intriguing. In vitro and transgenic studies of MLC1F/3F regulatory elements have revealed an array of cis-acting modules that each drive a subset of the expression pattern of the two promoters. These cis-acting regulatory modules, including the MLC1F and 3F promoter regions and two skeletal muscle enhancers, control tissue-specificity, cell or fibre-type specificity, and the spatiotemporal regulation of gene expression, including positional information. How each of these regulatory modules acts and how their individual activites are integrated to coordinate transcription at this locus are discussed.


Subject(s)
Gene Expression Regulation , Genetic Variation , Muscle, Skeletal/physiology , Myosin Light Chains/genetics , Animals , Base Sequence , Humans , Molecular Sequence Data , Muscle Fibers, Skeletal/physiology , Muscle, Skeletal/embryology , Transcription, Genetic , Transgenes
7.
Dev Dyn ; 217(1): 75-85, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10679931

ABSTRACT

Many cardiac genes are broadly expressed in the early heart and become restricted to the atria or ventricles as development proceeds. Additional transcriptional differences between left and right compartments of the embryonic heart have been described recently, in particular for a number of transgenes containing cardiac regulatory elements. We now demonstrate that three myosin genes which become transcriptionally restricted to the atria between embryonic day (E) 12.5 and birth, alpha-myosin heavy chain (MHC), myosin light chain (MLC) 1A and MLC2A, are coordinately downregulated in the compact myocardium of the left ventricle before that of the right ventricle. alpha-MHC protein also accumulates in the right, but not left, compact ventricular myocardium during this period, suggesting that this transient regionalization contributes to fktal heart function. dHAND and eHAND, basic helix-loop-helix transcription factors known to be expressed in the right and left ventricles respectively at E10. 5, remain regionalized between E12.5 and E14.5. Downregulation of alpha-MHC, MLC1A, and MLC2A in iv/iv embryos, which have defective left/right patterning, initiates in the morphological left (systemic) ventricle regardless of its anatomical position on the right or left hand side of the heart. This points to the importance of left/right ventricular differences in sarcomeric gene expression patterns during fktal cardiogenesis and indicates that these differences originate in the embryo in response to anterior-posterior patterning of the heart tube rather than as a result of cardiac looping. Dev Dyn 2000;217:75-85.


Subject(s)
Atrial Function , Gene Expression Regulation, Developmental , Myosins/biosynthesis , Myosins/genetics , Ventricular Function , Animals , Down-Regulation , Heart Atria/embryology , Heart Ventricles/embryology , Helix-Loop-Helix Motifs , Mice , Protein Isoforms/biosynthesis , Protein Isoforms/genetics , Transcription Factors/physiology
8.
J Chromatogr A ; 850(1-2): 375-80, 1999 Jul 30.
Article in English | MEDLINE | ID: mdl-10457500

ABSTRACT

Corrosion of aluminum alloy structures costs the US Air Force in the order of US$1 x 10(9) annually. Corrosion develops in areas of overlap such as aircraft lap-splice joints and under protective organic coatings. Capillary electrophoresis (CE) has been used to determine the local chemistries at these corrosion sites of solutions that were extracted using a microsampling system. Analysis of the local solution within lap-splice joints from aircraft has been performed in two ways: rehydration of corrosion products and direct microsampling. The solutions collected were analyzed with CE to quantitatively determine the species present during corrosion. The most common ions detected were Cl-, NO2-, NO3-, HCO3-, K+, Al3+, Ca2+, Na+ and Mg2+. Studies of the solution chemistry under local coating defects are required to understand coating failure and develop more durable coatings. A microsampling system and micro pH sensor were developed to extract solution from and measure pH in defects with diameters as small as 170 microns. Actively corroding defects contained high concentrations of Cl-, Al3+, Mg2+, Mn2+ and Cu2+ whereas only trace levels of Mg2+ were found in repassivated defects. The effects of these species on initiation and propagation of corrosion are discussed.


Subject(s)
Aluminum/chemistry , Electrophoresis, Capillary/methods , Aircraft , Alloys/chemistry , Aluminum/analysis , Anions/analysis , Cations/analysis , Corrosion , Oxidation-Reduction
9.
J Chromatogr A ; 850(1-2): 381-9, 1999 Jul 30.
Article in English | MEDLINE | ID: mdl-10457501

ABSTRACT

The environment-assisted cracking (EAC) susceptibility of some aluminum alloys used for airplane structural components currently limits their use in the peak strength condition. Understanding the mechanism of EAC will facilitate the development of crack-resistant alloys with optimum mechanical properties. One component towards understanding the fundamental processes responsible for EAC is a comprehensive knowledge of the chemical conditions within cracks. The present work uses capillary electrophoresis (CE) to quantify the crack chemistry in order to provide insight into the nature of the mechanism controlling cracking. The highly restricted geometry of cracks in metals means that a crack typically contains less than 10 microliters of solution. The high mass sensitivity combined with the inherently robust nature of CE makes it an ideal analytical technique for this application. Complicating factors in the accurate determination of the crack environment include high levels of sodium present from the test solution. Low sample volume and analyte matrix complexity necessitated the development of specific sampling, extraction and analysis methods. Analysis of the crack solutions in EAC-susceptible material revealed high levels of Al3+, Mg2+, Zn2+, and Cl- near the crack tip. Cations arise from the anodic dissolution of the alloy, whereas chloride ingress from the external environment occurs to maintain solution electroneutrality within the crack. In contrast, EAC-resistant material exhibited significantly lower concentrations of dissolution products.


Subject(s)
Alloys/chemistry , Aluminum/chemistry , Electrophoresis, Capillary/methods , Alloys/analysis , Aluminum/analysis , Anions/analysis , Cations/analysis , Corrosion , Oxidation-Reduction
10.
Trends Cardiovasc Med ; 9(1-2): 3-10, 1999.
Article in English | MEDLINE | ID: mdl-10189961

ABSTRACT

Differential regulation of cardiac gene expression in vertebrates has been extensively documented in the context of atrial and ventricular morphogenesis. Recent data, largely from the analysis of transgene and endogenous gene expression patterns, have revealed transcriptional differences between left and right cardiac chambers which suggest that the heart is composed of a series of distinct transcriptional domains. Such phenomena provide regional markers (cardiosensors) for the fine analysis of normal and abnormal heart development. Regional subdivisions and transcriptional heterogeneity within the myocardium emerge in response to patterning of the precardiac mesoderm and early heart tube on the anterior-posterior axis, and to embryonic left-right signals which dictate the direction of cardiac looping. Several families of transcription factors have been characterized which may be implicated in the regionalization of myocardial gene expression.


Subject(s)
Heart/embryology , Transcription, Genetic/genetics , Animals , Chick Embryo , Gene Expression Regulation, Developmental , Genetic Markers/genetics , Heart Atria/embryology , Heart Ventricles/embryology , Mesoderm/physiology , Mice , Mice, Transgenic/genetics , Morphogenesis/genetics , Rats , Transcription Factors/genetics , Transgenes/genetics
11.
Med Phys ; 25(9): 1741-50, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9775382

ABSTRACT

In recent years, magnetic-resonance imaging of gelatin doped with the Fricke solution has been applied to the direct measurement of three-dimensional (3D) radiation dose distributions. However, the 3D dose distribution can also be imaged more economically and efficiently using the method of optical absorption computed tomography. This is accomplished by first preparing a gelatin matrix containing a radiochromic dye and mapping the radiation-induced local change in the optical absorption coefficient. Ferrous-Benzoic-Xylenol (FBX) was the dye of choice for this investigation. The complex formed by Fe3+ and xylenol orange exhibits a linear change in optical attenuation (cm-1) with radiation dose in the range between 0 and 1000 cGy, and the local concentration of this complex can be probed using a green laser light (lambda = 543.5 nm). An optical computed tomography (CT) scanner was constructed analogous to a first-generation x-ray CT scanner, using a He-Ne laser, photodiodes, and rotation-translation stages controlled by a personal computer. The optical CT scanner itself can reconstruct attenuation coefficients to a baseline accuracy of < 2% while yielding dose images accurate to within 5% when other uncertainties are taken into account. Optical tomography is complicated by the reflection and refraction of light rays in the phantom materials, producing a blind spot in the transmission profiles which, results in a significant dose artifact in the reconstructed images. In this report we develop corrections used to reduce this artifact and yield accurate dosimetric maps. We also report the chemical reaction kinetics, the dose sensitivity and spatial resolution (< 1 mm3) obtained by optical absorption computed tomography. The article concludes with sample dose distributions produced by "cross-field" 6 MV x-ray beams, including a radiosurgery example.


Subject(s)
Radiographic Image Interpretation, Computer-Assisted/methods , Radiometry/instrumentation , Radiotherapy Planning, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Benzoic Acid , Biophysical Phenomena , Biophysics , Ferrous Compounds , Gels , Humans , Optics and Photonics/instrumentation , Phantoms, Imaging , Radiotherapy Planning, Computer-Assisted/statistics & numerical data , Technology, Radiologic , Xylenes
12.
J Mol Cell Cardiol ; 30(6): 1067-81, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9689582

ABSTRACT

It has recently emerged that transcriptional differences exist between left and right cardiac chambers. An example is provided by transgenic mice with an nlacZ reporter gene under transcriptional control of the fast skeletal muscle alkali myosin light chain (MLC) 3 promoter and 3' enhancer, which express beta-galactosidase in a left ventricular-right atrial dominant pattern in the developing and adult heart. Here, we demonstrate that endogenous MLC3F transcripts are also left/right regionalised in the mouse heart during embryonic development. Regionalisation is observed as early as embryonic day (E) 8.5, and by E10.5 MLC3F transcripts are present predominantly in the future left ventricle and right atrium, and to a lesser extent in the left atrium. Subsequently, MLC3F transcripts are down-regulated in the left ventricle, and by E12.5 expression is restricted to both atria and left-ventricular trabeculae. No MLC3F protein can be detected in the adult or embryonic mouse heart, suggesting that post-transcriptional regulation prevents this fast myosin isoform contributing to myocardial contraction. Left ventricular-right atrial dominant MLC3F transgenes therefore reflect transitory left/right regionalisation of the endogenous gene, unlike other reported cases of transgene regionalisation. MLC3F transgenes, however, maintain an embryonic-like distribution throughout development suggesting that myocardial gene expression is controlled by distinct temporal, as well as spatial, regulatory modules.


Subject(s)
Heart/growth & development , Myocardium/metabolism , Myosin Light Chains/genetics , Myosin Light Chains/metabolism , Age Factors , Animals , Base Sequence , Gene Expression Regulation, Developmental , Heart/embryology , Heart Atria/metabolism , Heart Ventricles/metabolism , Mice , Mice, Inbred Strains , Mice, Transgenic , Molecular Sequence Data , Transcription, Genetic , Transgenes
13.
Virology ; 246(2): 317-28, 1998 Jul 05.
Article in English | MEDLINE | ID: mdl-9657950

ABSTRACT

Although dengue (DEN) virus is the etiologic agent of dengue fever, the most prevalent vector-borne viral disease in the world, precise information on the antigenic structure of the dengue virion is limited. We have prepared a set of murine monoclonal antibodies (MAbs) specific for the envelope (E) glycoprotein of DEN 2 virus and used these antibodies in a comprehensive biological and biochemical analysis to identify 16 epitopes. Following domain nomenclature developed for the related flavivirus, tick-borne encephalitis, three functional domains were identified. Five epitopes associated with domain A were arranged in three spatially independent regions. These A-domain epitopes were destroyed by reduction, and antibodies reactive with these epitopes were able to block virus hemagglutination, neutralize virus infectivity, and block virus-mediated cell membrane fusion. Domain-A epitopes were present on the full-length E glycoprotein, a 45-kDa tryptic peptide representing its first 400 amino acids (aa) and a 22-kDa tryptic peptide representing at least aa 1-120. Four epitopes mapped into domain B, as determined by their partial resistance to reduction and the localization of these epitopes on a 9-kDa tryptic or chymotryptic peptide fragment (aa 300-400). One domain-B-reactive MAb was also capable of binding to a DEN 2 synthetic peptide corresponding to aa 333-351 of the E glycoprotein, confirming the location of this domain. Domain-B epitopes elicited MAbs that were potent neutralizers of virus infectivity and blocked hemagglutination, but they did not block virus-mediated cell-membrane fusion. Domains A and B were spatially associated. As with tick-borne encephalitis virus, determination of domain C was more problematic; however, at least four epitopes had biochemical characteristics consistent with C-domain epitopes.


Subject(s)
Antibodies, Viral/immunology , Antigens, Viral/immunology , Dengue Virus/immunology , Epitope Mapping , Epitopes, B-Lymphocyte/immunology , Viral Envelope Proteins/immunology , Animals , Antibodies, Monoclonal/immunology , Antigens, Viral/chemistry , Binding Sites , Binding, Competitive , Cell Line , Epitopes, B-Lymphocyte/chemistry , Hemagglutination Inhibition Tests , Humans , Jamaica , Male , Membrane Fusion , Mice , Mice, Inbred BALB C , Models, Molecular , Neutralization Tests , Peptide Fragments/chemical synthesis , Peptide Fragments/immunology , Peptide Mapping , Protein Conformation , Structure-Activity Relationship , Viral Envelope Proteins/chemistry
14.
Virology ; 246(2): 317-28, July 5, 1998.
Article in English | MedCarib | ID: med-1655

ABSTRACT

Although dengue (DEN) virus is the etiologic agent of dengue fever, the most prevalent vector-borne viral disease in the world, precise information on the antigenic structure of the dengue virion is limited. We have prepared a set of murine monoclonal antibodies (Mabs) specific for the envelope (E) glycoprotein of DEN 2 virus and used these antibodies in a comprehensive biological and biochemical analysis to identify 16 epitopes. Following domain nomenclature developed for the related flavivirus, tick-bourne encephalitis, three functional domains were identified. Five epitopes associated with domain A were arranged in three spatially independently regions. These A-domain epitopes were destroyed by reduction, and antibodies reactive with these epitopes were able to block virus hemagglutination, neutralize virus infectivity, and block virus haemagglutination, neutralize virus infectivity, and block virus-mediated cell membrane fusion. Domain-A epitopes were present on the full-length E glycoprotein, a 45-kDa tryptic peptide representing its first 400 amino acids (aa) and a 22-kDA tryptic peptide representing at least aa 1-120. Four epitopes mapped into domain B, as determined by their partial resistance to reduction and the localization of these epitopes on a 9-kDa tryptic or chymotryptic peptide fragment (aa 300-400). One domain-B-reactive MAb was also capable of binding to a DEN 2 synthetic peptide corresponding to aa 333-351 of the E glycoprotein, confirming the location of this domain. Domain-B epitopes elicited MAbs that were potent neutralizers of virus infectivity and blocked hemagglutination, but they did not block virus-mediated cell-membrane fusion. Domains A and B were spatially associated. As with tick-bourne encephalitis virus, determination of domain C was more problematic: however, at least four epitopes and biochemical characteristics consistent with C-domain epitopes(AU)


Subject(s)
21003 , Humans , Antibodies, Viral/immunology , Antigens, Viral/immunology , Dengue Virus/immunology , Epitope Mapping , Viral Envelope Proteins/immunology , Hemagglutination Inhibition Tests , Jamaica , Membrane Fusion , Mice , Mice, Inbred BALB C , Models, Molecular , Neutralization Tests , Peptide Fragments/chemical synthesis , Peptide Fragments/immunology , Peptide Mapping , Protein Conformation , Structure-Activity Relationship , Viral Envelope Proteins/chemistry , Antibodies, Monoclonal/immunology , Antigens, Viral/chemistry , Binding Sites , Binding, Competitive , Cell Line
15.
J Immunol ; 160(4): 1565-72, 1998 Feb 15.
Article in English | MEDLINE | ID: mdl-9469411

ABSTRACT

Activation of the complement cascade and ligation of complement C3 receptors on B cells represent an important bridge between innate and Ag-specific acquired immunity. We show here that cross-linking of mouse CD21 (complement receptor type 2, CR2, C3d receptor) and CD35 (complement receptor type 1, CR1, C3b/C4b receptor) or co-cross-linking of CD21/CD35 and surface IgM rapidly up-regulates both B7-1 and B7-2 expression on murine resting splenic B cells. CD21/CD35-mediated up-regulation of both B7-1 and B7-2 expression is observed within 14 h, while other stimuli up-regulate only B7-2 but not B7-1 at this early time point. Consistent with the increase in B7 levels, BALB/c B cells on which surface IgM and CD21/CD35 have been co-cross-linked stimulate C57BL/6 T cells more effectively than controls. This CD21/CD35-enhanced allogeneic MLR is blocked nearly completely by anti-B7-2 mAbs and partially by anti-B7-1 mAbs. In addition, cross-linking of CD19, which is physically associated with CD21/CD35, leads to increased B7-1 and B7-2 expression. These data suggest that CD21/CD35 ligation results in enhanced B cell Ag presentation using costimulatory mechanisms shared with other activators and thus works cooperatively in this process. Rapid up-regulation of B7-1 expression, a unique response to CD21/CD35 and CD19 cross-linking, may be a particularly important effect of C3-containing ligands. We propose that CD21/CD35- and CD19-mediated B7-1 and B7-2 up-regulation is an important mechanism by which complement activation links innate and acquired immunity.


Subject(s)
Antigens, CD19/metabolism , Antigens, CD/biosynthesis , B-Lymphocytes/metabolism , B7-1 Antigen/biosynthesis , Membrane Glycoproteins/biosynthesis , Receptors, Complement 3b/metabolism , Receptors, Complement 3d/metabolism , Spleen/metabolism , Animals , Antibodies, Monoclonal/pharmacology , Antigens, CD/immunology , Antigens, CD19/immunology , B-Lymphocytes/cytology , B-Lymphocytes/immunology , B7-1 Antigen/immunology , B7-2 Antigen , Cell Line , Cells, Cultured , Interphase/immunology , Lymphocyte Activation , Lymphocyte Culture Test, Mixed , Membrane Glycoproteins/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Receptors, Complement 3b/immunology , Receptors, Complement 3d/immunology , Spleen/cytology , Spleen/immunology , Up-Regulation/immunology
16.
Dev Biol ; 187(2): 183-99, 1997 Jul 15.
Article in English | MEDLINE | ID: mdl-9242416

ABSTRACT

Embryonic and fetal stages of skeletal muscle development are characterized by the differential expression of a number of muscle-specific genes. These include the products of independent promoters at the fast myosin light chain 1F/3F locus. In the mouse embryo MLC1F transcripts accumulate in embryonic skeletal muscle from E9, 4-5 days before high-level accumulation of MLC3F transcripts. A 3' enhancer can activate MLC1F and MLC3F promoters in differentiated muscle cells in vitro and in transgenic mice; both promoters, however, are activated at the time of MLC1F transcript accumulation. We now demonstrate the presence of a second muscle-specific enhancer at this locus, located in the intron separating the MLC1F and MLC3F promoters. Transgenic mice containing the intronic, but lacking the 3' enhancer, express high levels of an nlacZ reporter gene from the MLC3F promoter in adult fast skeletal muscle fibers. In contrast to the 3' enhancer, the intronic element is inactive both in embryonic muscle cells in vivo and in embryonic myocyte cultures. The intronic enhancer is activated at the onset of fetal development in both primary and secondary muscle fibers, at the time of endogenous MLC3F transcript accumulation. Late-activated MLC3F transgenes thus provide a novel in toto marker of fetal myogenesis. These results suggest that temporal regulation of transcription at the MLC1F/3F locus is controlled by separate enhancers which are differentially activated during embryonic and fetal development.


Subject(s)
Enhancer Elements, Genetic , Gene Expression Regulation, Developmental , Muscle, Skeletal/embryology , Myosin Light Chains/genetics , Animals , Base Sequence , Cell Differentiation , Embryo, Mammalian , Fetus , Fluorescent Antibody Technique , In Situ Hybridization , Introns , Mice , Mice, Transgenic , Molecular Sequence Data , Sequence Analysis, DNA , Time Factors , Transcription, Genetic
17.
Genomics ; 24(3): 509-15, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7713502

ABSTRACT

Tandem arrays of simple sequence repeat units are among the most unstable regions of mammalian genomes. Mutational instability at such loci depends on both repeat unit sequence and DNA sequences external to the tandem array, which have been recently implicated in polarized variability at human minisatellites. The characteristics of DNA sequences flanking the mouse minisatellite Ms6-hm have been investigated. This locus has a high mutation rate both in the germline and during early somatic development and is composed of a hypervariable tandem array of 500-2000 pentanucleotide repeat units flanked by a transposon-like long terminal repeat sequence of the mouse transcript (MT) family. A subpopulation of MT elements in the mouse genome are shown to flank a 1.1-kb internal sequence, consistent with their classification within a newly defined mammalian retrotransposon-like superfamily (MaLR). A second mouse minisatellite, Hm-2, also originates from within a MaLR LTR. Hm-2 is related to Ms6-hm in repeat unit sequence and profiles of germline and somatic instability; at both loci the tandem array has amplified from precisely the same point within the LTR. The similar origins of Ms6-hm and Hm-2 suggest that flanking MaLR sequences may be involved in mutational processes at these loci.


Subject(s)
DNA, Satellite/genetics , Repetitive Sequences, Nucleic Acid , Retroelements , Animals , Base Sequence , Consensus Sequence , DNA Primers/genetics , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred Strains , Molecular Sequence Data , Mutation , Recombination, Genetic , Sequence Homology, Nucleic Acid
18.
Genomics ; 17(1): 121-8, 1993 Jul.
Article in English | MEDLINE | ID: mdl-8406443

ABSTRACT

The highly variable mouse minisatellite Hm-2 is located on chromosome 9 and consists of GGCA tetranucleotide repeats with alleles containing up to 5000 repeat units. This locus is unstable with a germline mutation rate to new length alleles of at least 3.6% per gamete. Hm-2 also shows substantial somatic instability, producing mutational mosaicism detectable in 20% of adult mice. Analysis of allele dosage in mice carrying somatic mutations, plus studies of mosaicism in mouse embryos and extraembryonic tissues, suggests that somatic mutant alleles preferentially arise during preimplantation development and particularly during the first two cell divisions after fertilization.


Subject(s)
Blastocyst , DNA, Satellite/genetics , Embryonic and Fetal Development/genetics , Mice, Inbred Strains/genetics , Repetitive Sequences, Nucleic Acid , Alleles , Animals , Base Sequence , Chromosome Mapping , Mice , Mice, Inbred Strains/embryology , Molecular Sequence Data , Mosaicism/genetics , Mutation , Organ Specificity
19.
Farmaco ; 47(9): 1215-23, 1992 Sep.
Article in English | MEDLINE | ID: mdl-1300127

ABSTRACT

A chromatographic method for quantifying the potential memory-enhancing agent CL 275,838 (I) in human plasma with a limit of detection of 1.25 ng/ml is described. The procedure relies on isolation of the compounds from plasma constituents using the Sep-pack C18 cartridge, resolution by reverse-phase high pressure liquid chromatography (HPLC) and post-column oxidation of the eluate peak to from a derivative which can be measured by fluorescence detection. Peak height and compound I concentration were linearly related from 1.25 to 25 ng/ml. Intra- and inter-day validation studies indicated an acceptable precision and reproducibility of the method within the concentration range investigated, the overall coefficient of variation being less than 15%.


Subject(s)
Memory/drug effects , Piperazines/blood , Pyrazoles/blood , Pyrimidines/blood , Chromatography, High Pressure Liquid , Humans , Male , Oxidation-Reduction , Piperazines/chemistry , Piperazines/pharmacology , Pyrazoles/chemistry , Pyrazoles/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Quality Control , Solvents , Spectrometry, Fluorescence
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