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1.
J Dent Res ; 100(7): 673-676, 2021 07.
Article in English | MEDLINE | ID: mdl-33906484

Subject(s)
COVID-19 , Humans , SARS-CoV-2
2.
Radiography (Lond) ; 24(4): 298-303, 2018 11.
Article in English | MEDLINE | ID: mdl-30292497

ABSTRACT

INTRODUCTION: A study was proposed to examine the impact to patients and the Oncology review team, of extending the role of the Therapeutic Radiographer to undertake follow up review of prostate cancer patients who have completed a radical course of external beam radiotherapy treatment. METHOD: A total of 30 patients attending for routine radiotherapy follow up were included in an observational study. Patients were assigned for review with a Doctor or a Therapeutic Radiographer using 1:1 randomisation and a number of time points were recorded and analysed. RESULTS: Of the 44 patients screened, 30 patients were recruited. Average time from scheduled appointment time to departure from clinic was 36 min for both the doctor and Therapeutic Radiographer. The average length of Consultation was 19 min for the Therapeutic Radiographer and 10 min for the Doctor. Average length of wait for patients from scheduled appointment time to being taken for review was 17 min for the Therapeutic Radiographer and 25 min for the Doctor. Of the patients who completed questionnaires, 23/28 had no preference of reviewer, 2/28 declared a preference to be seen by a doctor, whilst 3/28 stated a preference for review with a Therapeutic Radiographer. CONCLUSION: The results of the study are encouraging and should be further investigated in an attempt of developing what would be a very rewarding aspect of the Therapeutic Radiographers role.


Subject(s)
Aftercare/methods , Allied Health Personnel , Prostatic Neoplasms/radiotherapy , Radiography/methods , Adult , Allied Health Personnel/organization & administration , Humans , Male , Patient Satisfaction , Professional Role , Prospective Studies , Surveys and Questionnaires
3.
Br J Radiol ; 84(1005): 813-8, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21159811

ABSTRACT

OBJECTIVE: Consistency in target organ and organ at risk position from planning to treatment is an important basic principle of radiotherapy. This study evaluates the effectiveness of bladder-filling instructions in achieving a consistent and reproducible bladder volume at the time of planning CT and daily during the course of radical radiotherapy for prostate cancer. It also assessed the rate of bladder filling before and at the end of radiotherapy. METHODS: 30 men attending for radiation therapy planning for prostate cancer received written and verbal bladder-filling instructions. They had their bladder volume assessed using a bladder ultrasound scanner post-void, immediately prior to planning CT scan and then daily immediately prior to treatment while in the therapy position. The inflow was calculated using the void and full bladder volumes and the time for the bladder to fill. RESULTS: The mean bladder volume at the time of planning was 282 ml (range 89-608 ml, standard deviation (SD) = 144.5 ml). This fell during treatment, with a mean value for all treatments of 189 ml (range 11-781 ml, SD = 134 ml). During radiotherapy, 76% (828/1090), 53% (579/1090) and 36% (393/1090) of bladder volumes had >50 ml, >100 ml and >150 ml difference, respectively when compared with their volume at the time of planning. Inflow reduced from 4.6 ml min(-1), SD = 2.9 min(-1) at planning to 2.5 min(-1), SD = 1.8 min(-1) after radiotherapy. CONCLUSION: The Bladderscan device (BVI 6400 Bladderscan, Verathon Medical UK, Sandford, UK) provides an effective means of assessing bladder volume prior to radiotherapy for prostate cancer. The evaluated bladder-filling protocol does not produce consistent, reproducible bladder volumes for radiotherapy.


Subject(s)
Prostatic Neoplasms/physiopathology , Prostatic Neoplasms/radiotherapy , Radiotherapy, Conformal , Urinary Bladder/diagnostic imaging , Aged , Humans , Male , Middle Aged , Observer Variation , Organ Size , Pilot Projects , Prostatic Neoplasms/pathology , Tomography, X-Ray Computed , Ultrasonography , Urinary Bladder/pathology
4.
Aust Vet J ; 87(12): 469-75, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19930160

ABSTRACT

OBJECTIVE: To determine the prevalence of mastitis pathogens in high-producing intensive dairy herds in New South Wales. DESIGN: Field survey. PROCEDURE: Milk samples from the mastitis-affected quarter were collected from cows on five high-producing dairy farms in NSW. The 820 samples were cultured using standard microbiological culture techniques. RESULTS: Bacteria or fungi were isolated from 83.3% of samples (683/820). More than two colony types were isolated from 16.7% of samples (137/820), two types from 6.6% (54/820), and one type from 52.3% (429/820). No bacteria were isolated from 24.4% (200/820) of the primary cultures, but enrichment cultures of these samples yielded single colony type bacterial isolates from 36.5% (73/200) of samples. Environmental pathogens, including coliforms, environmental Streptococcus and Staphylococcus spp., made up 91% (555/610) of isolates and accounted for 33.6% (205/610), 41.6% (254/610) and 15.7% (96/610), respectively, of isolates. Escherichia coli accounted for 76.1% (156/205) of the coliform isolates, Streptococcus uberis and Streptococcus dysgalactiae accounted for 32.3% (82/254) and 28.0% (71/254), respectively, of the environmental streptococcal isolates. Contagious pathogens were uncommon, comprising only 2.5% (15/610) of the total isolates. CONCLUSION: The incidence and causes of mastitis are largely influenced by farm management. The relatively high prevalence of coliform mastitis in the intensive high-producing herds in this survey contrasts with the low incidence reported in surveys of pasture-based herds in Victoria. If the Australian dairy industry continues its current trend of intensification, coliform intra-mammary infections may emerge as an increasingly important cause of mastitis.


Subject(s)
Dairying/methods , Environmental Microbiology , Mastitis, Bovine/epidemiology , Mastitis, Bovine/microbiology , Milk/microbiology , Animals , Cattle , Colony Count, Microbial , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae Infections/veterinary , Escherichia coli Infections/epidemiology , Escherichia coli Infections/veterinary , Female , New South Wales/epidemiology , Prevalence , Staphylococcal Infections/epidemiology , Staphylococcal Infections/veterinary , Streptococcal Infections/epidemiology , Streptococcal Infections/veterinary
5.
J Dent Res ; 88(4): 318-22, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19407150

ABSTRACT

Amelogenin and ameloblastin, the major enamel matrix proteins, are important for enamel mineralization. To identify their synergistic roles in enamel development, we generated Amel X(-/-)/Ambn(-/-) mice. These mice showed additional enamel defects in comparison with Amel X(-/-) or Ambn(-/-) mice. In 7-day-old Amel X(-/-)/Ambn(-/-) mice, not only was the ameloblast layer irregular and detached from the enamel surface, as in Ambn(-/-), but also, the enamel width was significantly reduced in the double-null mice as compared with Amel X(-/-) or Ambn(-/-) mice. Proteomic analysis of the double-null teeth revealed increased levels of RhoGDI (Arhgdia), a Rho-family-specific guanine nucleotide dissociation inhibitor, which is involved in important cellular processes, such as cell attachment. Both Amel X(-/-)/Ambn(-/-) mice and Ambn(-/-) mice displayed positive staining with RhoGDI antibody in the irregularly shaped ameloblasts detached from the matrix. Ameloblastin-regulated expression of RhoGDI suggests that Rho-mediated signaling pathway might play a role in enamel formation.


Subject(s)
Amelogenesis/physiology , Amelogenin/physiology , Dental Enamel Proteins/physiology , Dental Enamel/ultrastructure , Amelogenesis/genetics , Amelogenin/genetics , Animals , Dental Enamel/physiology , Dental Enamel Proteins/genetics , Incisor/ultrastructure , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Mutant Strains , Molar/ultrastructure
6.
Vaccine ; 26(14): 1751-8, 2008 Mar 25.
Article in English | MEDLINE | ID: mdl-18329764

ABSTRACT

Intensive livestock production and management systems are associated with increased fecal-oral pathogen transmission and a resultant high prevalence of multiple Salmonella serovars in many large dairy farms and feedlots. Thus, it is imperative to develop livestock vaccines that are capable of eliciting potent states of cross-protective immunity against a diversity of serovars of a given species. Immunization with modified live Salmonella enterica serovar Typhimurium vaccine strains, that lack the DNA adenine methylase (Dam), confers cross-protective immunity in murine and avian models of typhoid fever as well as in a bovine model of salmonellosis. Here we examined whether a dam mutant Typhimurium vaccine (serogroup B) has the capacity to elicit cross-protection against a virulent challenge with an emerging, clinically relevant, and multi-drug resistant strain of serovar Newport (serogroup C2-C3) that has been associated with clinical disease in recent salmonellosis outbreaks in calves. Vaccinated animals challenged with Newport exhibited a significant attenuation of clinical disease (improved attitude scores, increased daily weight gains and reduced fever and diarrhea) and a concomitant reduction in Newport fecal shedding and colonization of mesenteric lymph nodes and lungs compared to non-vaccinated control animals. The capacity to elicit cross-protective immunity in calves suggests that dam mutant vaccines have potential application toward the prevention and control of Salmonella infection in commercial livestock production systems wherein livestock are exposed to a diversity of Salmonella serovars.


Subject(s)
Cattle Diseases/immunology , Salmonella Infections, Animal/immunology , Salmonella Vaccines/genetics , Salmonella Vaccines/immunology , Salmonella typhimurium/genetics , Salmonella typhimurium/immunology , Site-Specific DNA-Methyltransferase (Adenine-Specific)/genetics , Animals , Cattle , Cattle Diseases/prevention & control , Cross Reactions , Feces/microbiology , Immunity/immunology , Lung/microbiology , Lymph Nodes/microbiology , Mesentery/microbiology , Salmonella Infections, Animal/prevention & control
7.
Aust Vet J ; 86(4): 124-9, 2008 Apr.
Article in English | MEDLINE | ID: mdl-18363984

ABSTRACT

OBJECTIVE: To conduct a serologic survey and define pili antigenic variability via the serologic cross-reactivity of Moraxella bovis isolates from naturally occurring infectious bovine keratoconjunctivitis (IBK) outbreaks in Australia. This project applies to the development of an M bovis pili-based vaccine targeting Australian strains originating from intensive cattle producing regions. PROCEDURE: Ocular swabs were collected from cattle affected with clinical signs of IBK from 25 veterinary practices. Standard criteria were used to identify 70 M bovis. Pure, piliated isolates were evaluated with a modified competitive enzyme-linked immunosorbent assay (ELISA) for cell-bound M bovis pili to determine their serologic cross-reactivity with pili of vaccinal bacterin strains EPP63, FLA64, and SAH 38. RESULTS: Sixty-four percent (45/70) of M bovis isolates demonstrated homologous pili antigens to a vaccinal strain. M bovis isolates homologous to one of the three vaccinal strains were obtained in 77% (34/44) of IBK outbreaks sampled. No IBK outbreak had isolates homologous to more than one vaccinal strain; however, 29% (10/34) of outbreaks with a cross-reacting strain had non-cross-reacting strains as well. CONCLUSION: The similar prevalence of pilus antigen homology to strain FLA64 was observed with isolates derived from NSW, Tasmania, and Victoria, compared with results of prior smaller serologic studies, suggests that the common pilus antigens in M bovis within Australia have been relatively stable over the last 20 years. The prevalence of a limited number of pilus antigens in M bovis suggest that the application of a vaccine containing the bacterial strains EPP63, FLA64, and SAH38 may provide a useful management tool for reducing production losses associated with IBK in Australia.


Subject(s)
Bacterial Vaccines/immunology , Cattle Diseases/immunology , Disease Outbreaks/veterinary , Keratoconjunctivitis, Infectious/immunology , Moraxella bovis/immunology , Moraxellaceae Infections/immunology , Animals , Antigens, Bacterial/blood , Australia/epidemiology , Cattle , Cattle Diseases/epidemiology , Cattle Diseases/prevention & control , Cornea/microbiology , Cross Reactions , Disease Outbreaks/prevention & control , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Keratoconjunctivitis, Infectious/epidemiology , Keratoconjunctivitis, Infectious/prevention & control , Male , Moraxella bovis/classification , Moraxella bovis/isolation & purification , Moraxellaceae Infections/epidemiology , Moraxellaceae Infections/prevention & control , Prevalence , Vaccination/veterinary
8.
Gait Posture ; 27(2): 189-95, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17466520

ABSTRACT

The conventional rigid spinal orthosis and the flexible spinal orthosis, SpineCor, have different treatment principles in the management of adolescent idiopathic scoliosis (AIS). These may influence the patients' gait pattern and clinical outcome. In this study, gait analysis on patients with AIS undergoing these two orthotic interventions were conducted. The patients' lower limb kinematic and kinetic data during level walking were collected using a motion analysis system and two force platforms in four test conditions: pre-intervention, having used the orthosis for 1 month and 1 year (in and out of the orthosis). Twenty-one subjects were randomly assigned to the rigid spinal orthosis group (10 subjects) and the SpineCor group (11 subjects). Neither group showed gait asymmetry when comparing the convex and concave sides in the four test conditions. However, significant reduction in the range of motion of the pelvis and hip joints in the coronal plane were found. Although patients with AIS undergoing these two orthotic interventions showed significant changes in walking pattern within the study period, their long-term effect on gait and function requires further investigation through long-term prospective studies.


Subject(s)
Braces , Scoliosis/physiopathology , Scoliosis/rehabilitation , Adolescent , Analysis of Variance , Biomechanical Phenomena , Child , Female , Humans
9.
Aust Vet J ; 85(1-2): 65-9, 2007.
Article in English | MEDLINE | ID: mdl-17300463

ABSTRACT

Infectious bovine keratoconjunctivitis (IBK) is one of the most common diseases of cattle and is of major economic importance. If the primary aetiological agent, Moraxella bovis, is successfully eliminated from ocular tissues corneal ulcers heal at a constant rate. If treatment is unsuccessful ulcer reoccurrence may follow initial healing. Appropriate antimicrobial selection requires knowledge of antimicrobial sensitivities and distribution in ocular tissues and tears. Drugs may be delivered to the eye in several ways: subconjunctival injection, topical application and systemic administration. While therapeutic efficacy is affected by the frequency and mode of drug delivery, variations between intensive and extensive enterprises dictate the practical method of antimicrobial delivery. Specific recommendations for antimicrobial therapies targeting Australian IBK outbreaks are dependent upon antimicrobial pharmacokinetics, drug regulations and associated costs.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Cattle Diseases/drug therapy , Keratoconjunctivitis, Infectious/drug therapy , Moraxella bovis/isolation & purification , Moraxellaceae Infections/veterinary , Animals , Anti-Bacterial Agents/administration & dosage , Cattle , Drug Administration Routes , Moraxella bovis/drug effects , Moraxellaceae Infections/drug therapy , Treatment Outcome
11.
J Dent Res ; 85(2): 144-9, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16434732

ABSTRACT

We previously reported that amelogenin isoforms M180 and leucine-rich amelogenin peptide (LRAP) are expressed in the periodontal region, and that their absence is associated with increased cementum defects in amelogenin-knockout (KO) mice. The aim of the present study was to characterize the functions of these isoforms in osteoclastogenesis and in the proliferation and migration of cementoblast/periodontal ligament cells. The co-cultures of wild-type (WT) osteoclast progenitor and KO cementoblast/periodontal ligament cells displayed more tartrate-resistant acid phosphatase (TRAP)-positive cells than the co-cultures of WT cells. The addition of LRAP to both co-cultures significantly reduced RANKL expression and the TRAP-positive cells. Proliferation and migration rates of the KO cementoblast/periodontal ligament cells were lower than those of WT cells and increased with the addition of either LRAP or P172 (a porcine homolog of mouse M180). Thus, we demonstrate the regulation of osteoclastogenesis by LRAP, and the proliferation and migration of cementoblast/periodontal ligament cells by LRAP and P172.


Subject(s)
Dental Cementum/physiology , Dental Enamel Proteins/physiology , Osteoclasts/physiology , Periodontal Ligament/physiology , Amelogenin , Animals , Carrier Proteins/biosynthesis , Cell Movement/drug effects , Cell Movement/physiology , Cell Proliferation/drug effects , Cells, Cultured , Coculture Techniques , Dental Cementum/cytology , Dental Cementum/drug effects , Dental Enamel Proteins/pharmacology , Membrane Glycoproteins/biosynthesis , Mice , Mice, Knockout , Osteoclasts/cytology , Osteoclasts/drug effects , Periodontal Ligament/cytology , Periodontal Ligament/drug effects , Protein Isoforms/pharmacology , Protein Isoforms/physiology , RANK Ligand , Receptor Activator of Nuclear Factor-kappa B , Recombinant Proteins/pharmacology , Specific Pathogen-Free Organisms , Swine
12.
J Dent Res ; 84(1): 69-72, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15615879

ABSTRACT

Currently, much remains unknown of the genes that mediate the biological events during growth and fusion of the midfacial region, and the possible pathways through which these genes function. We took advantage of high-throughput microarray analysis to search for genes that may play a critical role in the growth and fusion of the midfacial region to become the primary palate. We identified several genes that were potentially expressed at different levels between tail somite (TS) 6-8 (pre-fusion) and TS 12-14 (fusion) in the 3 midfacial processes. Expression of 4 of these genes (Tbx14/15, Dickkopf-1, Fibroblast Growth Factor 8, and Keratin-18) was further verified by reverse-transcription/quantitative PCR and in situ hybridization at the 2 stages of midfacial development. With the identification of these genes, and possibly others, functional analyses can be conducted to improve our understanding of the mechanisms and pathways by which the midface forms.


Subject(s)
Embryonic Development/genetics , Genetic Markers , Palate/embryology , Animals , Fibroblast Growth Factor 8 , Fibroblast Growth Factors/biosynthesis , Gene Expression Profiling , Gene Expression Regulation, Developmental , Intercellular Signaling Peptides and Proteins , Keratins/biosynthesis , Keratins/genetics , Mice , Mice, Inbred C57BL , Microarray Analysis , Proteins/genetics , Reverse Transcriptase Polymerase Chain Reaction , T-Box Domain Proteins/genetics
13.
J Dent Res ; 82(7): 558-64, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12821719

ABSTRACT

Cleft lip is a common congenital malformation, and labioplasty performed on infants to repair such defects often results in severe scar formation. Since TGF-beta 3 has been implicated in wound healing, we therefore hypothesized that TGF-beta 3 functions to reduce scarring after cleft lip repair. In this investigation, we demonstrated that exogenous TGF-beta 3 reduced scar formation in an incised and sutured mouse lip in vivo. During labioplasty, endogenous TGF-beta 3 expression was also elevated. In vitro experiments showed that exogenous TGF-beta 3 reduced type I collagen accumulation. Furthermore, TGF-beta 3 inhibited alpha-smooth-muscle actin expression, a marker for myofibroblasts. In tandem, TGF-beta 3 induced the expression and activity of MMP-9. Analysis of our data suggests that TGF-beta 3 is normally secreted following labioplastic wound healing. An elevated level of TGF-beta 3 reduces type I collagen deposition by restricting myofibroblast differentiation and thereby collagen synthesis, and by promoting collagen degradation by MMP-9. In combination, these events lead to TGF-beta 3-mediated reduced scar formation.


Subject(s)
Cicatrix/prevention & control , Cleft Lip/surgery , Collagen Type I/biosynthesis , Lip/surgery , Oral Surgical Procedures/methods , Transforming Growth Factor beta/pharmacology , Actins/biosynthesis , Actins/drug effects , Animals , Animals, Newborn , Blotting, Western , Collagen Type I/drug effects , Enzyme Induction/drug effects , Extracellular Matrix/drug effects , Matrix Metalloproteinase 9/biosynthesis , Mice , Mice, Mutant Strains , Recombinant Proteins/pharmacology , Reverse Transcriptase Polymerase Chain Reaction , Transforming Growth Factor beta/physiology , Transforming Growth Factor beta3
14.
J Dent Res ; 81(10): 688-94, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12351667

ABSTRACT

TGF-beta3 mediates epithelial-mesenchymal transformation during normal fusion of lip and palate, but how TGF-beta3 functions during cleft lip repair remains unexplored. We hypothesize that TGF-beta3 promotes fetal cleft lip repair and fusion by increasing the availability of mesenchymal cells. In this investigation, we demonstrated that cleft lips in mouse fetuses were repaired by fetal surgery, producing scarless fusion. At the site of the operation, we first observed an infusion of platelets expressing TGF-beta3, followed by increased expression of cyclin D1 and tenascin-C, and coupled with increased mesenchymal cell proliferation. In an ex vivo serumless culture system, cleft lip explants fused in the presence of exogenous TGF-beta3. Cultured lips also showed up-regulation in cyclin D1 and tenascin-C expression. These findings suggest that microsurgical repair of cleft lip in the fetus that produced scarless fusion is mediated by TGF-beta3 regulation of mesenchymal cell proliferation and migration at the site of repair.


Subject(s)
Cicatrix/prevention & control , Cleft Lip/surgery , Fetal Diseases/surgery , Transforming Growth Factor beta/physiology , Animals , Antimetabolites , Blood Platelets/metabolism , Bromodeoxyuridine , Cell Division , Cell Movement , Culture Media, Serum-Free , Cyclin D1/metabolism , Epithelium/drug effects , Fetus/surgery , Immunohistochemistry , Mesoderm/drug effects , Mesoderm/pathology , Mice , Microsurgery , Organ Culture Techniques , Platelet Count , Reverse Transcriptase Polymerase Chain Reaction , Tenascin/metabolism , Transforming Growth Factor beta/metabolism , Transforming Growth Factor beta/therapeutic use , Transforming Growth Factor beta3 , Up-Regulation
15.
Dev Dyn ; 225(1): 35-45, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12203718

ABSTRACT

Dach1 is a mouse homologue of the Drosophila dachshund gene, which is a key regulator of cell fate determination during eye, leg, and brain development in the fly. We have investigated the expression and growth factor regulation of Dach1 during pre- and postnatal skeletal development in the mouse limb to understand better the function of Dach1. Dach1 was expressed in the distal mesenchyme of the early embryonic mouse limb bud and subsequently became restricted to the tips of digital cartilages. Dach1 protein was localized to postmitotic, prehypertrophic, and early hypertrophic chondrocytes during the initiation of ossification centers, but Dach1 was not expressed in growth plates that exhibited extensive ossification. Dach1 colocalized with Runx2/Cbfa1 in chondrocytes but not in the forming bone collar or primary spongiosa. Dach1 also colocalized with cyclin-dependent kinase inhibitors p27 (Kip1) and p57 (Kip2) in chondrocytes of the growth plate and in the epiphysis before the formation of the secondary ossification center. Because fibroblast growth factors (FGF), bone morphogenetic proteins (BMP), and hedgehog molecules (Hh) regulate skeletal patterning of the limb bud and chondrocyte maturation in developing endochondral bones, we investigated the regulation of Dach1 by these growth and differentiation factors. Expression of Dach1 in 11 days postcoitus mouse limb buds in organ culture was up-regulated by implanting beads soaked in FGF1, 2, 8, or 9 but not FGF10. BMP4-soaked beads down-regulated Dach1 expression, whereas Shh and bovine serum albumin had no effect. Furthermore, FGF4 or 8 could substitute for the apical ectodermal ridge in maintaining Dach1 expression in the limb buds. Immunolocalization of FGFR2 and FGFR3 revealed overlap with Dach1 expression during skeletal patterning and chondrocyte maturation. We conclude that Dach1 is a target gene of FGF signaling during limb skeletal development, and Dach1 may function as an intermediary in the FGF signaling pathway regulating cell proliferation or differentiation.


Subject(s)
Bone Development , Eye Proteins/metabolism , Fibroblast Growth Factors/metabolism , Gene Expression Regulation, Developmental , Signal Transduction , Animals , Body Patterning , Cell Cycle Proteins/metabolism , Cell Differentiation , Cell Division , Chondrocytes/metabolism , Cyclin-Dependent Kinase Inhibitor p27 , Cyclin-Dependent Kinase Inhibitor p57 , Extremities/embryology , Immunohistochemistry , In Situ Hybridization , Mice , Nuclear Proteins/metabolism , Recombinant Proteins/metabolism , Time Factors , Transcription Factors/metabolism , Tumor Suppressor Proteins/metabolism
16.
Nucleic Acids Res ; 30(5): 1213-23, 2002 Mar 01.
Article in English | MEDLINE | ID: mdl-11861914

ABSTRACT

Msx2 is a homeobox gene expressed in multiple embryonic tissues which functions as a key mediator of numerous developmental processes. YY1 is a bi-functional zinc finger protein that serves as a repressor or activator to a variety of promoters. The role of YY1 during embryogenesis remains unknown. In this study, we report that Msx2 is regulated by YY1 through protein-DNA interactions. During embryogenesis, the expression pattern of YY1 was observed to overlap in part with that of Msx2. Most notably, during first branchial arch and limb development, both YY1 and Msx2 were highly expressed, and their patterns were complementary. To test the hypothesis that YY1 regulates Msx2 gene expression, P19 embryonal cells were used in a number of expression and binding assays. We discovered that, in these cells, YY1 activated endogenous Msx2 gene expression as well as Msx2 promoter-luciferase fusion gene activity. These biological activities were dependent on both the DNA binding and activation domains of YY1. In addition, YY1 bound specifically to three YY1 binding sites on the proximal promoter of Msx2 that accounted for this transactivation. Mutations introduced to these sites reduced the level of YY1 transactivation. As bone morphogenetic protein type 4 (BMP4) regulates Msx2 expression in embryonic tissues and in P19 cells, we further tested whether YY1 is the mediator of this BMP4 activity. BMP4 did not induce the expression of YY1 in early mouse mandibular explants, nor in P19 cells, suggesting that YY1 is not a required mediator of the BMP4 pathway in these tissues at this developmental stage. Taken together, these findings suggest that YY1 functions as an activator for the Msx2 gene, and that this regulation, which is independent of the BMP4 pathway, may be required during early mouse craniofacial and limb morphogenesis.


Subject(s)
Bone Morphogenetic Proteins/pharmacology , DNA-Binding Proteins/genetics , DNA-Binding Proteins/physiology , Gene Expression Regulation, Developmental , Transcription Factors/physiology , Transcriptional Activation , Animals , Bone Morphogenetic Protein 4 , Branchial Region/embryology , Branchial Region/metabolism , DNA-Binding Proteins/biosynthesis , DNA-Binding Proteins/chemistry , Electrophoretic Mobility Shift Assay , Erythroid-Specific DNA-Binding Factors , Extremities/embryology , Genes, Reporter , Homeodomain Proteins , In Situ Hybridization , Mandible/drug effects , Mandible/embryology , Mandible/metabolism , Mice , Promoter Regions, Genetic , Protein Structure, Tertiary , RNA, Messenger/biosynthesis , Signal Transduction , Trans-Activators/chemistry , Trans-Activators/genetics , Trans-Activators/physiology , Transcription Factors/chemistry , Transcription Factors/genetics , Transfection , Tumor Cells, Cultured , YY1 Transcription Factor
17.
Dev Dyn ; 222(2): 252-62, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11668602

ABSTRACT

During early mouse embryogenesis, cranial neural crest cells (CNCC) emigrate from the posterior midbrain and rhombomeres 1 and 2 of the anterior hindbrain into the first branchial arch-derived maxillary and mandibular processes and there provide cell lineages for several phenotypes, including cartilage, bone, and tooth. Here, we report that Sox9 and Msx2 were coexpressed in a subpopulation of CNCC during their migration. Because Sox9 is a transactivator of chondrogenesis, and Msx genes can act as transcriptional repressors, we hypothesized that Sox9 expression indicates the determination of CNCC-derived chondrogenic cell lineage and that Msx2 represses chondrogenic differentiation until CNCC migration is completed within the mandibular processes. To test whether Msx2 represses chondrogenesis, we designed experiments to inhibit Msx2 function in migratory CNCC in primary cultures through the expression of loss-of-function Msx2 mutants. We showed that infection of migratory CNCC with adenovirus Msx2 mutants accelerated the rate and extent of chondrogenesis, as indicated by the expression level of type II collagen and aggrecan, and the amount of alcian blue staining. Adenovirus infections did not apparently interfere with CNCC proliferation or migration. These findings suggest that an important early event in craniofacial morphogenesis is a transient expression of both Sox9 and Msx2 during emigration into the forming mandibular processes followed by restricted expression of Sox9 within CNCC- derived chondroprogenitor cells. We conclude that Msx2 serves as a repressor of chondrogenic differentiation during CNCC migration.


Subject(s)
Chondrocytes/cytology , DNA-Binding Proteins/genetics , Extracellular Matrix Proteins , Neural Crest/cytology , Neural Crest/embryology , Adenoviridae/genetics , Aggrecans , Alcian Blue , Animals , Cartilage/cytology , Cartilage/embryology , Cell Differentiation/physiology , Cell Movement/physiology , Cells, Cultured , Collagen Type II/genetics , Coloring Agents , Gene Transfer Techniques , High Mobility Group Proteins/genetics , Homeodomain Proteins , Humans , Kidney/cytology , Lectins, C-Type , Mandibulofacial Dysostosis/genetics , Mice , Mutagenesis/physiology , Proteoglycans/genetics , Reverse Transcriptase Polymerase Chain Reaction , SOX9 Transcription Factor , Staining and Labeling , Transcription Factors/genetics
18.
Genomics ; 77(1-2): 18-26, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11543628

ABSTRACT

The gene DACH is a human homologue of Drosophila melanogaster dachshund (dac), which encodes a nuclear factor essential for determining cell fates in the eye, leg, and nervous system of the fly. To investigate possible connections between DACH and inherited developmental disorders, we have characterized the human DACH genomic structure and investigated the tissue and cellular distribution of the mouse DACH1 protein during development. DACH spans 400 kb and is encoded by 12 exons. The predominant DACH transcript is 5.2 kb and encodes a 706-amino-acid protein with an observed molecular weight of 97 kDa.DACH mRNA was detected in multiple adult human tissues including kidney and heart. The mouse DACH1 protein was immunolocalized to specific cell types within the developing kidneys, eyes, cochleae, and limb buds. Data suggest genetic linkage of the limb bud patterning defect postaxial polydactyly type A (designated PAP-A2, MIM 602085) to a 28-cM interval on chromosome 13 that includes DACH. However, mutation analysis of DACH in this PAP-A2 pedigree revealed no sequence differences in the coding region, splice sites, or proximal promoter region. The data presented will allow for the analysis of DACH as a candidate for other developmental disorders affecting the limbs, kidneys, eyes, ears, and other sites of DACH expression.


Subject(s)
Drosophila Proteins , Nuclear Proteins/genetics , Alternative Splicing , Amino Acid Sequence , Animals , Base Sequence , Blotting, Northern , DNA Mutational Analysis , Embryo, Mammalian/metabolism , Exons , Family Health , Female , Gene Expression , Gene Expression Regulation, Developmental , Genes/genetics , Genetic Predisposition to Disease/genetics , Humans , Immunoblotting , Introns , Mice , Nuclear Proteins/metabolism , Polydactyly/genetics , RNA/genetics , RNA/metabolism , Tissue Distribution
19.
J Cell Biol ; 154(2): 275-81, 2001 Jul 23.
Article in English | MEDLINE | ID: mdl-11470817

ABSTRACT

To elucidate the contribution of the extracellular microfibril-elastic fiber network to vertebrate organogenesis, we generated fibrillin 2 (Fbn2)-null mice by gene targeting and identified a limb-patterning defect in the form of bilateral syndactyly. Digit fusion involves both soft and hard tissues, and is associated with reduced apoptosis at affected sites. Two lines of evidence suggest that syndactily is primarily due to defective mesenchyme differentiation, rather than reduced apoptosis of interdigital tissue. First, fusion occurs before appearance of interdigital cell death; second, interdigital tissues having incomplete separation fail to respond to apoptotic clues from implanted BMP-4 beads. Syndactyly is associated with a disorganized matrix, but with normal BMP gene expression. On the other hand, mice double heterozygous for null Fbn2 and Bmp7 alleles display the combined digit phenotype of both nullizygotes. Together, these results imply functional interaction between Fbn2-rich microfibrils and BMP-7 signaling. As such, they uncover an unexpected relationship between the insoluble matrix and soluble factors during limb patterning. We also demonstrate that the Fbn2- null mutation is allelic to the recessive shaker-with-syndactyly (sy) locus on chromosome 18.


Subject(s)
Body Patterning/genetics , Extracellular Matrix/metabolism , Limb Deformities, Congenital/genetics , Microfibrils/metabolism , Microfilament Proteins/deficiency , Syndactyly/genetics , Transforming Growth Factor beta , Alleles , Animals , Apoptosis , Body Patterning/drug effects , Bone Morphogenetic Protein 4 , Bone Morphogenetic Protein 7 , Bone Morphogenetic Proteins/deficiency , Bone Morphogenetic Proteins/genetics , Bone Morphogenetic Proteins/metabolism , Bone Morphogenetic Proteins/pharmacology , Chromosomes/genetics , Drug Implants , Fibrillin-2 , Fibrillins , Forelimb/embryology , Forelimb/pathology , Gene Targeting , Hindlimb/embryology , Hindlimb/pathology , Limb Deformities, Congenital/pathology , Mesoderm/cytology , Mice , Mice, Knockout , Microfibrils/pathology , Microfilament Proteins/genetics , Microfilament Proteins/metabolism , Signal Transduction/genetics , Syndactyly/metabolism , Syndactyly/pathology
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