Home About us Contact
|
Home About us Contact | ||
|
|
||
Nasal Bone (nasal + bone)
Terms modified by Nasal Bone Selected AbstractsDynamic morphological changes in the skulls of mice mimicking human Apert syndrome resulting from gain-of-function mutation of FGFR2 (P253R)JOURNAL OF ANATOMY, Issue 2 2010Xiaolan Du Abstract Apert syndrome is caused mainly by gain-of-function mutations of fibroblast growth factor receptor 2. We have generated a mouse model (Fgfr2+/P253R) mimicking human Apert syndrome resulting from fibroblast growth factor receptor 2 Pro253Arg mutation using the knock-in approach. This mouse model in general has the characteristic skull morphology similar to that in humans with Apert syndrome. To characterize the detailed changes of form in the overall skull and its major anatomic structures, euclidean distance matrix analysis was used to quantitatively compare the form and growth difference between the skulls of mutants and their wild-type controls. There were substantial morphological differences between the skulls of mutants and their controls at 4 and 8 weeks of age (P < 0.01). The mutants showed shortened skull dimensions along the rostrocaudal axis, especially in their face. The width of the frontal bone and the distance between the two orbits were broadened mediolaterally. The neurocrania were significantly increased along the dorsoventral axis and slightly increased along the mediolateral axis, and also had anteriorly displayed opisthion along the rostrocaudal axis. Compared with wild-type, the mutant mandible had an anteriorly displaced coronoid process and mandibular condyle along the rostrocaudal axis. We further found that there was catch-up growth in the nasal bone, maxilla, zygomatic bone and some regions of the mandible of the mutant skulls during the 4,8-week interval. The above-mentioned findings further validate the Fgfr2+/P253R mouse strain as a good model for human Apert syndrome. The changes in form characterized in this study will help to elucidate the mechanisms through which the Pro253Arg mutation in fibroblast growth factor receptor 2 affects craniofacial development and causes Apert syndrome. [source] Literature Review and suggested protocol for managing ultrasound soft markers for Down syndrome: Thickened nuchal fold, echogenic bowel, shortened femur, shortened humerus, pyelectasis and absent or hypoplastic nasal boneJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2007Article first published online: 10 MAY 200, M Bethune Summary Mid-trimester soft markers have been linked with Down syndrome and other aneuploidies. There are many other prenatal screening tests available with better detection rates for Down syndrome than the mid-trimester ultrasound. Many patients confronted with the diagnosis of a soft marker become anxious and may request a diagnostic test (amniocentesis) despite the associated risk of miscarriage. This is also despite the fact that most fetuses with an isolated soft marker are chromosomally normal. The management of a pregnancy with a soft marker must therefore be planned in a manner designed to minimize patient anxiety. Likelihood ratios can be used to modify a patient's ,prior risk' (based on age or prior screening tests) and create a new risk. This calculation may help identify a subset of patients suitable for further investigation. It has been proposed that ,negative' likelihood ratios can be used to reduce a patient's risk if no soft marker is found at a mid-trimester ultrasound. There remain concerns about this approach and further research is required before this approach enters common practice. The published work surrounding the management of thickened nuchal fold, echogenic bowel, shortened femur, shortened humerus, pyelectasis (renal pelvis dilatation) and hypoplastic nasal bone is reviewed. Each soft marker has different associations and individual management plans for each of these soft markers are presented. Although isolated single umbilical artery is not usually considered a soft marker of aneuploidy, a management plan for this common finding is also included. [source] Anthropometric and cephalometric measurements in X-linked hypohidrotic ectodermal dysplasiaORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 4 2007MO Lexner Structured Abstract Authors,,, Lexner MO, Bardow A, Bjorn-Jorgensen J, Hertz JM, Almer L, Kreiborg S. Objective,,, To describe the somatic development and craniofacial morphology in males affected with hypohidrotic ectodermal dysplasia (HED) and female carriers and to find clinical markers for early clinical diagnosis of possible female carriers. Design,,, A clinical and radiographic examination of the affected males and the female carriers. Setting and sample population,,, Twenty-four affected males and 43 female carriers with a known mutation in the ED1 gene were examined in a dental clinic in either Copenhagen or Aarhus, Denmark. Experimental variables,,, Height, body mass index (BMI) and head circumference. Cephalometric analysis of the craniofacial morphology. Outcome measure,,, Data on the somatic and craniofacial development in the affected males and female carriers. Results,,, No difference was observed regarding body height in the affected males and female carriers, BMI values were lower than the mean in most affected boys and adolescence and head circumference was somewhat decreased in both groups compared to normative data. The cephalometric analysis showed a reduced maxilla length and prognathism, a normal size and shape of the mandible and a reduced sagittal jaw relationship in both HED groups. Furthermore, affected males had a retroclined nasal bone and a more anteriorly inclined maxilla. A short nose, protruding lips, reduced facial convexity and facial height, characterized the soft tissue profile of the affected males. In female carriers, the lips were significantly retruded when compared with controls. Conclusion,,, No specific somatic or cephalometric markers could be observed, in the female carrier group. [source] First-trimester nasal bone length in a normal Latin American populationPRENATAL DIAGNOSIS, Issue 2 2009Alexandra Casasbuenas Abstract Objectives To report normative data of nasal bone length (NBL) in first-trimester singleton fetuses in a normal cohort of Latin American women. Methods NBL was measured during routine first-trimester sonographic examination in 1040 singleton fetuses from an unselected population. Results NBL increased linearly with advancing gestational age (GA) [NBL (mm) = , 1.10 + 0.03 × GA (days), R2 = 0.21; p < 0.001]. Similarly, there was a linear relationship between the NBL and crown-lump length (CRL) [NBL (mm) = 0.41 + 0.02 × CRL (mm), R2 = 0.27; p < 0.001]. The NBLs at the 50th percentile in our population were 1.5, 1.7, and 1.9 mm at 11, 12, and 13 weeks of gestation, respectively. Conclusions Whereas categorizing a nasal bone as absent or present can be subjective because of variations in echogenicity due to technique and equipment, measurement of NBL is a more objective approach to nasal bone assessment in screening for aneuploidy. Measurement of NBL in the first trimester is feasible and can be easily obtained at the time of nuchal translucency assessment. The normative data we report can provide a reference for defining nasal bone hypoplasia in the first trimester in the Latin American population. Copyright © 2008 John Wiley & Sons, Ltd. [source] Maternal serum biochemistry at 11,13+6 weeks in relation to the presence or absence of the fetal nasal bone on ultrasonography in chromosomally abnormal fetuses: an updated analysis of integrated ultrasound and biochemical screeningPRENATAL DIAGNOSIS, Issue 11 2005Simona Cicero Abstract Background Screening for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness and maternal serum free ,-hCG and pregnancy associated plasma protein-A (PAPP-A) at 11,13+6 weeks of gestation is associated with a detection rate of 90%, for a false-positive rate of 5%. Recent evidence suggests that in about 70% of fetuses with trisomy 21 the nasal bone is not visible at the 11,13+6 week scan and that the frequency of absence of nasal bone differs in different ethnic groups. In addition, there is a relationship between absent nasal bone and nuchal translucency thickness. In a preliminary study we showed that while PAPP-A levels were lower and free ,-hCG levels were higher in trisomy 21 fetuses with an absent nasal bone, this difference was not statistically different. In fetuses with trisomy 13 and trisomy 18, there is also a high (57 and 67%) incidence of an absent nasal bone. The aim of this present study was to extend our examination of whether the level of maternal serum biochemical markers is independent of the presence or absence of the nasal bone in cases with trisomy 21 and to ascertain if any differences exist in cases with trisomies 13 and 18. Methods This study data comprised 100 trisomy 21 singleton pregnancies at 11,13+6 weeks of gestation from our previous study and an additional 42 cases analysed as part of routine OSCAR screening. A total of 34 cases with trisomy 18 and 12 cases with trisomy 13 were also available. Ultrasound examination was carried out for measurement of fetal NT and assessment of the presence or absence of the fetal nasal bone. Maternal serum free ,-hCG and PAPP-A were measured using the Kryptor rapid random access immunoassay analyser (Brahms Diagnostica AG, Berlin). The distribution of maternal serum free ,-hCG and PAPP-A in chromosomally abnormal fetuses with absent and present nasal bone was examined. Results The nasal bone was absent in 29 and present in 13 of the new trisomy 21 cases and in 98 (69%) and 44 respectively in the combined series. For the trisomy 18 cases, the nasal bone was absent in 19 (55.9%) cases and in 3 (25%) of cases of trisomy 13. There were no significant differences in median maternal age, median gestational age, NT delta, free ,-hCG MoM and PAPP-A MoM in trisomy 21 fetuses with and without a visible nasal bone, and similarly for those with trisomies 13 or 18. For a false-positive rate of 5%, it was estimated that screening with the four markers in combination with maternal age would be associated with a detection rate of 96% of cases with trisomy 21. For a false-positive rate of 0.5%, the detection rate was 88%. Conclusions There is no relationship between an absent fetal nasal bone and the levels of maternal serum PAPP-A or free ,-hCG in cases with trisomies 13, 18 or 21. An integrated sonographic and biochemical test at 11,13+6 weeks can potentially identify about 88% of trisomy 21 fetuses for a false-positive rate of 0.5%. Copyright © 2005 John Wiley & Sons, Ltd. [source] Ethnic variation of fetal nasal bone length between 11,14 weeks' gestationPRENATAL DIAGNOSIS, Issue 8 2005Fadi Collado Abstract Objective We sought to compare the fetal nasal bone length (FNBL) between different ethnic groups at 11,14 weeks' gestation. Methods FNBL and the FNBL/CRL ratio were measured in patients undergoing first trimester ultrasound for nuchal translucency (NT) and the ethnicity of the patient was recorded under four categories: non-Hispanic White, non-Hispanic black, Hispanic, and Chinese. Results Two hundred and one patients were included in the study. Measurement of the FNBL could not be obtained in nine patients (4.5%) and foetal nasal bone was absent in one fetus. Comparing the four groups, non-Hispanic White, non-Hispanic Black, Hispanic, and Asian, there were no statistical differences in crown-rump length (61 ± 14 mm; 68.6 ± 15 mm; 60.2 ± 14 mm; 62.4 ± 8.8 mm, respectively) or the NT (1.3 ± 0.5 mm; 1.25 ± 0.4 mm; 1.35 ± 1 mm; 1.4 ± 0.4 mm, respectively). However, the FNBL (2.9 ± 0.7 mm; 2.5 ± 0.6 mm; 2.5 ± 0.6 mm; 2.2 ± 0.4 mm, respectively, p < 0.01) and the FNBL/CRL ratio (0.049 ± 0.01, 0.045 ± 0.01, 0.043 ± 0.01, 0.037 ± 0.01, respectively, p < 0.01) were both statistically different, when comparing between these groups. Conclusion If the FNBL is to be introduced into first-trimester screening, it should be adjusted for ethnicity. Copyright © 2005 John Wiley & Sons, Ltd. [source] Is there an optimal gestation for ultrasound examination of fetal nasal bone in the first trimester?PRENATAL DIAGNOSIS, Issue 11 2004Pui Wah Hui No abstract is available for this article. [source] Histopathological findings of the nose of Down syndrome abortusesPRENATAL DIAGNOSIS, Issue 7 2003S. F. Wong Abstract Recent reports of absent nasal bone in fetuses with Down syndrome have sparked much interest in the use of this finding for the screening of Down syndrome. We describe the histopathological findings of nasal bones of two fetuses with Down syndrome, one with absence and the other with normal ossification of the nasal bone. We propose that histopathological examination of the nasal bone could improve the accuracy of diagnosis of nasal hypoplasia among Down syndrome abortuses. Copyright © 2003 John Wiley & Sons, Ltd. [source] Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnanciesPRENATAL DIAGNOSIS, Issue 6 2003Maria Angelica Zoppi Abstract Objectives The absence of nasal bone (NB) has been noted in trisomy 21 fetuses at first-trimester ultrasound, in high-risk pregnancies. In this study, the nasal bone was evaluated in relation to fetal karyotype, in unselected pregnancies. Methods From September 2001 to September 2002, the fetal facial profile was examined at the 11 to 14 weeks' scan for screening by nuchal translucency (NT). Risks for trisomy 21 were calculated using the Fetal Medicine Foundation's software, and the presence or absence of NB was noted. Prenatal karyotype and pregnancy outcomes were recorded. Results NT screening was performed in 5532 fetuses from 5425 pregnancies (85 twins, 8 triplets, 2 quadruplets). The visualization of fetal profile was obtained in 5525 fetuses (99.8%), and in 5491 fetuses (99.4%) the NB was present and in 34 cases (0.6%) it was absent. Fetal karyotype and pregnancy outcome were available in 3503 pregnancies, and 40 chromosomal abnormalities were diagnosed (27 trisomies 21, 5 trisomies 18, 2 trisomies 13, 3 Turner syndromes, 1 partial trisomy 9 and 2 others). The NB was absent in 19 (70%) trisomies 21, 4 trisomies 18 (80%), 2 Turner syndromes (66%), in the partial trisomy 9, in 7 normal karyotype fetuses (0.2%), and in a case with spontaneous first-trimester abortion before prenatal diagnosis. A significant difference was found between NT thickness, expressed as a multiple of the median, in trisomy 21 fetuses with present and absent nasal bone. Conclusions The absence of NB at 11 to 14 weeks is more frequent in fetuses with trisomy 21 and other aneuploidies than in normal karyotype fetuses. Copyright © 2003 John Wiley & Sons, Ltd. [source] Integrated ultrasound and biochemical screening for trisomy 21 using fetal nuchal translucency, absent fetal nasal bone, free ,-hCG and PAPP-A at 11 to 14 weeksPRENATAL DIAGNOSIS, Issue 4 2003Simona Cicero Abstract Background Screening for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness and maternal serum free ,-hCG and pregnancy-associated plasma protein-A (PAPP-A) at 11 to 14 weeks of gestation is associated with a detection rate of 90% for a false-positive rate of 5%. Recent evidence suggests that in about 70% of fetuses with trisomy 21, the nasal bone is not visible at the 11th- to 14th-week scan (Cicero et al., 2001). The aim of this study was to examine whether fetal NT thickness and the level of maternal serum biochemical markers is independent of the presence or absence of the nasal bone, and to estimate the performance of a screening test that integrates the two sonographic and the two biochemical markers. Methods This was a retrospective case-control study comprising 100 trisomy 21 and 400 chromosomally normal singleton pregnancies at 11 to 14 weeks of gestation. Ultrasound examination was carried out for measurement of fetal NT and assessment of the presence or absence of the fetal nasal bone. Maternal serum free ,-hCG and PAPP-A were measured using the Kryptor rapid random-access immunoassay analyser (Brahms Diagnostica GmbH, Berlin). The distribution of fetal NT, maternal serum free ,-hCG and PAPP-A in trisomy 21 fetuses with absent and present nasal bone was examined. Results The nasal bone was absent in 69 and present in 31 of the trisomy 21 fetuses. There were no significant differences in median maternal age, median gestational age, NT delta, free ,-hCG MoM and PAPP-A MoM in trisomy 21 fetuses with and without a visible nasal bone. For a false-positive rate of 5%, it was estimated that screening with the four markers in combination with maternal age would be associated with a detection rate of 97%. For a false-positive rate of 0.5%, the detection rate was 90.5%. Conclusions An integrated sonographic and biochemical test at 11 to 14 weeks can potentially identify about 90% of trisomy 21 fetuses for a false-positive rate of 0.5%. Copyright © 2003 John Wiley & Sons, Ltd. [source] Aspects of achondroplasia in the skulls of dwarf transgenic mice: A cephalometric studyTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2006Melissa Wadler Bloom Abstract Achondroplasia, the most common short-limbed dwarfism in humans, results from a single nucleotide substitution in the gene for fibroblast growth factor receptor 3 (FGFR3). FGFR3 regulates bone growth in part via the mitogen-activated protein kinase pathway (MAPK). To examine the role of this pathway in chondrocyte differentiation, a transgenic mouse was generated that expresses a constitutively active mutant of MEK1 in chondrocytes and exhibits dwarfing characteristics typical of human achondroplasia, i.e., shortened axial and appendicular skeletons, mid-facial hypoplasia, and dome-shaped cranium. In this study, cephalometrics of the MEK1 mutant skulls were assessed to determine if the MEK1 mice are a good model of achondroplasia. Skull length, arc of the cranial vault, and area, maximum and minimum diameters of the brain case were measured on digitized radiographs of skulls of MEK1 and control mice. Cranial base and nasal bone length and foramen magnum diameter were measured on midsagittal micro-CT sections. Data were normalized by dividing by the cube root of each animal's weight. Transgenic mice exhibited a domed skull, deficient midface, and (relatively) prognathic mandible and had a shorter cranial base and nasal bone than the wild-type. Skull length was significantly less in transgenic mice, but cranial arc was significantly greater. The brain case was larger and more circular and minimum diameter of the brain case was significantly greater in transgenic mice. The foramen magnum was displaced anteriorly but not narrowed. MEK1 mouse cephalometrics confirm these mice as a model for achondroplasia, demonstrating that the MAP kinase signaling pathway is involved in FGF signaling in skeletal development. © 2006 Wiley-Liss, Inc. [source] Biomechanics of the rostrum and the role of facial suturesJOURNAL OF MORPHOLOGY, Issue 1 2003Katherine L. Rafferty Abstract The rostrum is a large diameter, thin-walled tubular structure that receives loads from the teeth. The rostrum can be conceptualized both as a rigid structure and as an assemblage of several bones that interface at sutures. Using miniature pigs, we measured in vivo strains in rostral bones and sutures to gain a better understanding of how the rostrum behaves biomechanically. Strains in the premaxillary and nasal bones were low but the adjacent maxillary-premaxillary, internasal, and intermaxillary suture strains were larger by an order of magnitude. While this finding emphasizes the composite nature of the rostrum, we also found evidence in the maxillary and nasal bones for rigid structural behavior. Namely, maxillary strain is consistent with a short beam model under shear deformation from molar loading. Strain in the nasal bones is only partially supported by a long beam model; rather, a complex pattern of dorsal bending of the rostrum from incisor contact and lateral compression is suggested. Torsion of the maxilla is ruled out due to the bilateral occlusion of pigs and the similar working and balancing side strains, although it may be important in mammals with a unilateral bite. Torsional loading does appear important in the premaxillae, which demonstrate working and balancing side changes in strain orientation. These differences are attributed to asymmetrical incisor contact occurring at the end of the power stroke. J. Morphol. 257:33,44, 2003. © 2003 Wiley-Liss, Inc. [source] Histopathological findings of the nose of Down syndrome abortusesPRENATAL DIAGNOSIS, Issue 7 2003S. F. Wong Abstract Recent reports of absent nasal bone in fetuses with Down syndrome have sparked much interest in the use of this finding for the screening of Down syndrome. We describe the histopathological findings of nasal bones of two fetuses with Down syndrome, one with absence and the other with normal ossification of the nasal bone. We propose that histopathological examination of the nasal bone could improve the accuracy of diagnosis of nasal hypoplasia among Down syndrome abortuses. Copyright © 2003 John Wiley & Sons, Ltd. [source] | |||||||||||||