The existence of Merkel cells in the lingual connective tissue of the Surinam caiman, Caiman crocodilus crocodilus (order Crocodilia).
(1/15)
The tongue of the Surinam caiman (a reptilian species) was studied by light microscopy including immunohistochemistry for protein gene product 9.5 (PGP 9.5), and transmission electron microscopy. The connective tissue immediately under taste buds housed a cluster of cells immunoreactive for PGP 9.5. These cells synapsed on nerves, and their cytoplasm contained characteristic granules of 90 nm in the mean diameter, glycogen particles, and bundles of intermediate filaments. In light of these ultrastructural features, they were identified as Merkel cells. The Merkel cells were also surrounded by Schwann cells. These findings indicate that the present Merkel cell-neurite-Schwann cell complex is comparable to the avian Merkel corpuscle. On the basis of the granule localization in the cytoplasm, the caiman Merkel cell was presumed to be involved in not only mechanoreception but also endocrine or paracrine functions. (+info)
Cloning and expression analysis of the chick ortholog of TBX22, the gene mutated in X-linked cleft palate and ankyloglossia.
(2/15)
T-box genes constitute a conserved gene family with important roles in many developmental processes. Several family members have been implicated in human congenital diseases. Recently, mutations in TBX22 were found to cause X-linked cleft palate (CPX and ankyloglossia), a semidominant X-linked disorder affecting formation of the secondary palate. Here, we have cloned the chick ortholog of human TBX22 and have analyzed its expression during embryogenesis. Expression is very prominent in the somites and in the myotome, and in the mandible and maxilla of the developing jaw. Other sites of expression include the limbs, the cranial mesenchyme and the eye. Hence, Tbx22 expression domains encompass the regions important for the development of the disease phenotype. (+info)
Craniofacial expression of human and murine TBX22 correlates with the cleft palate and ankyloglossia phenotype observed in CPX patients.
(3/15)
Cleft palate with ankyloglossia (CPX; MIM 303400) is inherited as a Mendelian, semidominant X-linked disorder and has been described in several large families from different ethnic origins. It is a useful genetic model for non-syndromic cleft palate, a common congenital disorder. Recently, the underlying genetic defect in CPX was identified, where unique mutations were found in the T-box-containing transcription factor TBX22. Here we report two new familial cases with novel missense and insertion mutations, each occurring within the T-box domain and highlighting the functional significance of this DNA-binding motif. We describe TBX22 expression in early human development, where expression is found in the palatal shelves and is highest prior to elevation to a horizontal position above the tongue. mRNA is also detected in the base of the tongue in the region of the frenulum that corresponds to the ankyloglossia seen in CPX patients. Other sites of expression include the inferior portion of the nasal septum that fuses to the palatal shelves, the mesenchyme from which tooth buds develop, and the tooth buds themselves. We have also identified the orthologous mouse Tbx22 gene and performed expression analysis in E12.5-E17.5 mouse embryos. The location of mRNA expression closely correlates between mouse and human, while at later stages of development, we also detected expression in mouse lung and whisker follicles. We conclude that expression of TBX22 is entirely consistent with the CPX phenotype and that the mouse should provide a useful model for elucidating its role in craniofacial development. (+info)
The dorsal lingual epithelium of Rhinoclemmys pulcherrima incisa (Chelonia, Cryptodira).
(4/15)
This study employed light microscopic (LM), scanning electron microscopic (SEM), and transmission electron microscopic (TEM) methods to provide detailed morphological information on the histological and ultrastructural features of the dorsal tongue epithelium of Rhinoclemmys pulcherrima incisa. SEM revealed columnar papillae laterally, as well as papillae, which tend to have a ridge-like appearance in the center of the tongue. LM and TEM showed three different zones of lingual epithelium: a stratified apical area with serous cells at the top of the papillae, a stratified lateral area with both serous and mucus cells, and an unstratified glandular area consisting of distinct glandular ducts with mucus cells. Comparison with morphological data from other turtles shows that the lingual epithelial structure in R. p. incisa is in accordance with that observed for other generalized omnivores which prefer a terrestrial lifestyle, thus matching the ecological information about this species. (+info)
Newborn tongue-tie: prevalence and effect on breast-feeding.
(5/15)
OBJECTIVE: The purposes of this study were: (1) to determine whether breast-fed infants with tongue-tie have decreased rates of breast-feeding at 1 week and 1 month of age, (2) to determine the prevalence of tongue-tie, and (3) to test the usefulness of the Assessment Tool for Lingual Frenulum Function (ATLFF) in assessing the severity of tongue-tie in breast-feeding newborns. METHODS: A case-control design was used. All infants in the Regions Hospital newborn nursery were examined for tongue-tie. Tongue-tied babies were examined using the ATLFF. Two breast-feeding babies with normal tongues were identified and matched for each case. Mothers were interviewed when the babies were 1 week and 1 month old. RESULTS: The prevalence of tongue-tie was 4.2%. Forty-nine tongue-tied and 98 control infants were enrolled. Tongue-tied babies were 3 times as likely as control babies to be bottle fed only at 1 week [risk ratio (RR), 3.11; 95% confidence interval (CI), 1.21, 8.03) By 1 month, tongue-tied babies were as likely as controls to be bottle fed only. (RR, 1.00; 95% CI, 0.55, 1.82) Twelve of the tongue-tied infants had ATLFF scores of "Perfect," none had scores of "Acceptable," and 6 had scores of "Function Impaired." The remaining 31 infants had scores that fell into none of these categories. CONCLUSIONS: Tongue-tie is a relatively common condition in newborns. Affected infants are significantly more likely to be exclusively bottle-fed by 1 week of age. The ATLFF was not a useful tool to identify which tongue-tied infants are at risk for breast-feeding problems. (+info)
Prevalence, diagnosis, and treatment of ankyloglossia: methodologic review.
(6/15)
OBJECTIVE: To review the diagnostic criteria for, the prevalence of, and the effectiveness of frenotomy for treatment of ankyloglossia. DATA SOURCES: MEDLINE and CINAHL databases were searched for articles suitable for a methodologic review of studies on various aspects of ankyloglossia. STUDY SELECTION: Studies that presented data on patients and addressed ankyloglossia in relation to breastfeeding were selected. Case reports, case series, retrospective studies, prospective controlled studies, and randomized controlled trials were included in the analysis. Opinion pieces, literature reviews, studies without data on patients, studies that did not focus on breastfeeding, position statements, and surveys were excluded. SYNTHESIS: There is no well-validated clinical method for establishing a diagnosis of ankyloglossia. Five studies using different diagnostic criteria found a prevalence of ankyloglossia of between 4% and 10%. The results of 6 non-randomized studies and 1 randomized study assessing the effectiveness of frenotomy for improving nipple pain, sucking, latch, and continuation of breastfeeding all suggested frenotomy was beneficial. No serious adverse events were reported. CONCLUSION: Diagnostic criteria for ankyloglossia are needed to allow for comparative studies of treatment. Frenotomy is likely an effective treatment, but further randomized controlled trials are needed to confirm this. A reliable frenotomy decision rule is also needed. (+info)
Frenulotomy for breastfeeding infants with ankyloglossia: effect on milk removal and sucking mechanism as imaged by ultrasound.
(7/15)
Tbx22null mice have a submucous cleft palate due to reduced palatal bone formation and also display ankyloglossia and choanal atresia phenotypes.
(8/15)