ABSTRACT
OBJECTIVE: Type I myosins are molecular motors necessary for glucose transport in the cytoplasm and initiation of transcription in the nucleus. Two of these, MYO1H and MYO1C, are paralogs which may be important in the development of malocclusion. The objective of this study was to investigate their gene expression in the masseter muscle of malocclusion subjects. Two functionally related proteins known to contribute to malocclusion were also investigated: KAT6B (a chromatin remodelling epigenetic enzyme which is activated by MYO1C) and RUNX2 (a transcription factor regulating osteogenesis which is activated by KAT6B). DESIGN: Masseter muscle samples and malocclusion classifications were obtained from orthognathic surgery subjects. Muscle was sectioned and immunostained to determine fibre type properties. RNA was isolated from the remaining sample to determine expression levels for the four genes by TaqMan(®) RT-PCR. Fibre type properties, gene expression quantities and malocclusion classification were compared. RESULTS: There were very significant associations (P<0.0000001) between MYO1C and KAT6B expressions. There were also significant associations (P<0.005) between RUNX2 expression and masseter muscle type II fibre properties. Very few significant associations were identified between MYO1C and masseter muscle fibre type properties. CONCLUSIONS: The relationship between MYO1C and KAT6B suggests that the two are interacting in chromatin remodelling for gene expression. This is the nuclear myosin1 (NM1) function of MYO1C. A surprising finding is the relationship between RUNX2 and type II masseter muscle fibres, since RUNX2 expression in mature muscle was previously unknown. Further investigations are necessary to elucidate the role of RUNX2 in adult masseter muscle.
Subject(s)
Core Binding Factor Alpha 1 Subunit/genetics , Histone Acetyltransferases/genetics , Malocclusion/genetics , Masseter Muscle/metabolism , Myosin Type I/genetics , Female , Gene Expression , Humans , Male , Malocclusion/classification , Real-Time Polymerase Chain Reaction , Young AdultABSTRACT
BACKGROUND: The authors conducted a study to survey the perspectives of dentists regarding the 2010 American Dental Association (ADA) recommendation to seal non-cavitated carious lesions (NCCLs) in children and young adults. METHODS: The authors mailed a questionnaire to a randomly selected sample of 2,400 general dentists (GDs) and pediatric dentists (PDs) in the United States. The sample was chosen by the ADA's Survey Center. The questionnaire included two photographs of NCCLs (permanent first molar and premolar) in a 12-year-old child. Respondents were provided with radiographic findings and asked to choose from several management options. RESULTS: In the absence of radiographic evidence of caries, 37.4 percent and 42.3 percent of GDs and PDs, respectively, indicated that they would seal the NCCL in the molar. For the premolar, a significantly lower percentage of GDs than of PDs indicated that they would seal the NCCL. With radiographic evidence of caries in dentin, less than 4 percent of all dentists surveyed indicated that they would seal the NCCLs, and more than 90 percent indicated that they would remove the caries and place restorations. Less than 40 percent of dentists indicated that they sealed NCCLs in their practice. CONCLUSIONS: The U.S. dentists surveyed have not adopted evidence-based clinical recommendations regarding the sealing of NCCLs. Practice Implications. New educational and dissemination programs should be developed regarding these evidence-based caries management approaches.
Subject(s)
Dental Caries/prevention & control , Dental Fissures/prevention & control , Evidence-Based Dentistry , Pit and Fissure Sealants/therapeutic use , Practice Guidelines as Topic , Practice Patterns, Dentists' , Attitude of Health Personnel , Bicuspid/diagnostic imaging , Bicuspid/pathology , Child , Dental Restoration, Permanent , Dentin/diagnostic imaging , Female , General Practice, Dental , Guideline Adherence , Humans , Male , Molar/diagnostic imaging , Molar/pathology , Patient Care Planning , Pediatric Dentistry , Photography, Dental , Radiography , Surveys and Questionnaires , United StatesABSTRACT
We describe the rare finding of a T-cell acute lymphoblastic leukemia (T-ALL) and a pretreatment bone marrow karyotype mosaic for four distinct cell lines in a 4-year-old boy. G-banding analysis of metaphase cells identified a hyperdiploid cell line (52 chromosomes) trisomic for chromosomes 6, 9, 11, 13, 19, and 22. Fluorescence in situ hybridization (FISH) analysis demonstrated that these hyperdiploid cells were missing all three copies of the CDKN2A locus (alias p16/Ink4) at 9p21. FISH analysis of interphase nuclei identified two abnormal cell lines: the majority of cells with homozygous deletions of the CDKN2A locus and some with a heterozygous deletion. In addition, a normal signal pattern was identified in a few cells. This case represents a rare case of hyperdiploidy in T-ALL, and characterizes the clonal evolution of the 9p21 deletion leading to the abnormal karyotype.
Subject(s)
Gene Deletion , Genes, p16 , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics , Trisomy/genetics , Aneuploidy , Child, Preschool , Chromosome Mapping , Humans , In Situ Hybridization, Fluorescence , Karyotyping , MaleABSTRACT
We report the unique association of variable constitutional mosaicism 46,X, i(X)(p10)/46,XX with recurrent thrombocytopenia in a child with failure to thrive and apnea in infancy. Her bone marrow had equal distribution of the normal and abnormal cell lines at diagnosis, at nearly 6 years of age. Improvement of her pancytopenia and thrombocytopenia was concurrent with a decreasing level of mosaicism observed in multiple studies over the next 3 years. This suggests that extra copies of genes on the p-arm are inhibitory to blood cell maturation, with long-term selection against the i(Xp)-containing cells.
