Some Sweet and Bitter Tastants Stimulate Inhibitory Pathway of Adenylyl Cyclase Via Melatonin and Alpha 2-adrenergic Receptors in Xenopus Laevis Melanophores

American Journal of Physiology. Cell Physiology. Nov, 2003  |  Pubmed ID: 12839835

The sweeteners saccharin, D-tryptophan, and neohesperidin dihydrochalcone (NHD) and the bitter tastant cyclo(Leu-Trp) stimulated concentration-dependent pigment aggregation in a Xenopus laevis melanophore cell line similar to melatonin. Like melatonin, these tastants inhibited (by 45-92%) cAMP formation in melanophores; pertussis toxin pretreatment almost completely abolished the tastant-induced cAMP inhibition, suggesting the involvement of the inhibitory pathway (Gi) of adenylyl cyclase. The presence of luzindole (melatonin receptor antagonist) almost completely abolished the inhibition of cAMP formation induced by saccharin, D-tryptophan, and cyclo(Leu-Trp) but only slightly affected the inhibitory effect of NHD. In contrast, the presence of an alpha2-adrenergic receptor antagonist, yohimbine, almost completely abolished the inhibition of cAMP formation induced by NHD but had only a minor effect on that induced by the other tastants. Thus saccharin, D-tryptophan, and cyclo(Leu-Trp) are melatonin receptor agonists whereas NHD is an alpha2-adrenergic receptor agonist, but both pathways lead to the same transduction output and cellular response. Formation of D-myo-inositol 1,4,5-trisphosphate (IP3) in melanophores was reduced (15-58%, no concentration dependence) by saccharin, D-tryptophan, and cyclo(Leu-Trp) stimulation but increased by NHD stimulation. Tastant stimulation did not affect cGMP. Although some of the above tastants were found to be membrane permeant, their direct activation of downstream transduction components in this experimental system is questionable. MT1 and MT2 melatonin receptor mRNAs were identified in rat circumvallate papilla taste buds and nonsensory epithelium, suggesting the occurrence of MT1 and MT2 receptors in these tissues. Melatonin stimulation reduced the cellular content of cAMP in taste cells, which may or may not be related to taste sensation.

The Efficacy and Safety of 50 Mg Penicillin G Potassium Troches for Recurrent Aphthous Ulcers

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics. Dec, 2003  |  Pubmed ID: 14676759

To determine both the efficacy and safety of the topical application of 50 mg penicillin G potassium troches (Cankercillin) in the treatment of minor recurrent aphthous stomatitis (RAS).

Analysis of a Human Fungiform Papillae CDNA Library and Identification of Taste-related Genes

Chemical Senses. Jan, 2004  |  Pubmed ID: 14752036

Various genes related to early events in human gustation have recently been discovered, yet a thorough understanding of taste transduction is hampered by gaps in our knowledge of the signaling chain. As a first step toward gaining additional insight, the expression specificity of genes in human taste tissue needs to be determined. To this end, a fungiform papillae cDNA library has been generated and analyzed. For validation of the library, taste-related gene probes were used to detect known molecules. Subsequently, DNA sequence analysis was performed to identify further candidates. Of 987 clones sequenced, clustering results in 288 contigs. Comparison of these contigs with genomic databases reveals that 207 contigs (71.9%) match known genes, 16 (5.6%) match hypothetical genes, eight (2.8%) match repetitive sequences and 57 (19.8%) have no or low similarity to annotated genes. The results indicate that despite a high level of redundancy, this human fungiform cDNA library contains specific taste markers and is valuable for investigation of both known and novel taste-related genes.

Biochemical Enrichment and Biophysical Characterization of a Taste Receptor for L-arginine from the Catfish, Ictalurus Puntatus

BMC Neuroscience. Jul, 2004  |  Pubmed ID: 15282034

The channel catfish, Ictalurus punctatus, is invested with a high density of cutaneous taste receptors, particularly on the barbel appendages. Many of these receptors are sensitive to selected amino acids, one of these being a receptor for L-arginine (L-Arg). Previous neurophysiological and biophysical studies suggested that this taste receptor is coupled directly to a cation channel and behaves as a ligand-gated ion channel receptor (LGICR). Earlier studies demonstrated that two lectins, Ricinus communis agglutinin I (RCA-I) and Phaseolus vulgaris Erythroagglutinin (PHA-E), inhibited the binding of L-Arg to its presumed receptor sites, and that PHA-E inhibited the L-Arg-stimulated ion conductance of barbel membranes reconstituted into lipid bilayers.

Dentistry, Nursing, and Medicine: a Comparison of Core Competencies

Journal of Dental Education. Nov, 2005  |  Pubmed ID: 16275689

Health care, including oral health care and oral health education, is under great stress in the United States. The cost of and access to care, the cost of dental education, and a shortage of educators have led leaders in dental education, organized dentistry, and the public sector to underscore the problem. One of the proposed solutions is to find synergies and new health care and education models by building bridges among the health professions. One potential solution is being implemented at the NYU College of Dentistry (NYUCD). Dentistry and nursing are seemingly unrelated professions, and they are rarely if ever modeled together. That is about to change with the joining together of NYUCD and the Division of Nursing of the NYU Steinhardt School of Education in creating a College of Nursing within the College of Dentistry. This process has not been without controversy. Following the Division of Nursing's request to join NYUCD, and the subsequent announcement of the proposed combination by NYU in December 2004, some members of the dental profession responded by questioning the appropriateness of the merger and the similarity of the two programs. Nevertheless, substantial parallels exist in the education and practice of dentists and nurse practitioners (NP) including basic, social, and some clinical science education, practice models, research synergies, and community service. However, similarities in the core competencies of these professions have not been analyzed formally and in detail. Accordingly, the purpose of this study was to compare the core competencies of nurse practitioner and dental education programs. The results show a surprising overlap of the core competencies of the dental and nursing professions (38 percent partial or total overlap). A similar overlap with medicine also exists, albeit lower (25.4 percent). These results are notable because they demonstrate that the three health professions, independently of one another, developed very similar basic competencies and learning objectives. These data should encourage other health professions programs to seek new collaborative models for education, beyond the current silos of training, and new health care delivery systems as has been strongly recommended by the Institute of Medicine. Such collaborative education redirects health care toward providing truly interdisciplinary comprehensive primary care for patients.

The Birth of the Most Important 18th Century Dental Text: Pierre Fauchard's Le Chirurgien Dentiste

Journal of Dental Research. Oct, 2007  |  Pubmed ID: 17890667

Pierre Fauchard (1678-1761) is considered the father of modern dentistry. His seminal book, Le Chirurgien Dentiste, ou Traité des Dents (1728), is the discipline's first complete work. During the five years preceding its publication (1723-1728), Pierre Fauchard sought the opinions, contributions, and "approbation" (approval) of 19 of his colleagues: six physicians, 12 surgeons, and one dentist. The first and most important contributor to the manuscript was Jean Devaux, surgeon and mentor to Fauchard. The next six reviewers were illustrious physicians and scientists of the time: Philippe Hecquet, Jean-Claude Adrien Helvetius, Jean Baptiste Silva, Antoine DeJussieu, Raymond Jacob Finot, and Antoine Benignus Winslow. The subsequent 12 reviewers were all sworn-surgeons (certified by St. Côme), including a lone dentist, Laudumiey, surgeon-dentist to His Majesty, Philip V, King of Spain. Fauchard knew that for dentistry to be regarded as a learned profession, and perhaps for Fauchard to be recognized as its leader, he needed the support and approval of the establishment before publishing his book. This is an account of how he attained this endorsement.

Overcoming Barriers to Implementing Evidence-based Dentistry

Journal of Dental Education. Mar, 2008  |  Pubmed ID: 18316529

Assessment of Teaching Effectiveness in U.S. Dental Schools and the Value of Triangulation

Journal of Dental Education. Jun, 2008  |  Pubmed ID: 18519601

The routine evaluation of teaching effectiveness is important in improving faculty, departmental, and institutional efforts. There are three main categories of assessments: those performed by students, peers, and self. Although each category is independently valid, a collection of data from all three categories leads to a more comprehensive outcome and a creation of a triangulation model. The purpose of this study was to identify commonly used methods of assessing teaching effectiveness and to suggest the use of a triangulation model, which has been advocated in the literature on performance assessment as an optimal approach for evaluating teaching effectiveness. A twelve-question survey was sent to all U.S. dental schools to identify evaluation methods as well as to find evidence of triangulation. Thirty-nine out of fifty-seven schools responded. The majority of the schools used student evaluations (81 percent) and peer reviews (78 percent). A minority of schools reported using self-evaluations (31 percent). Less than one in five dental schools reported using all three strategies to achieve triangulation (19 percent). The three most commonly used evaluation methods ("performed routinely") were all in the student evaluation category. Less than half of the schools routinely evaluated clinical teaching effectiveness by any means (42 percent). In conclusion, dental schools should implement a triangulation process, in which evaluation data are obtained from students, peers, and self to provide a comprehensive and composite assessment of teaching effectiveness.

Sour Ageusia in Two Individuals Implicates Ion Channels of the ASIC and PKD Families in Human Sour Taste Perception at the Anterior Tongue

PloS One. 2009  |  Pubmed ID: 19812697

The perception of sour taste in humans is incompletely understood at the receptor cell level. We report here on two patients with an acquired sour ageusia. Each patient was unresponsive to sour stimuli, but both showed normal responses to bitter, sweet, and salty stimuli.

Characterization of Human Fungiform Papillae Cells in Culture

Chemical Senses. Sep, 2011  |  Pubmed ID: 21471186

The ability to maintain human fungiform papillae cells in culture for multiple cell cycles would be of considerable utility for characterizing the molecular, regenerative, and functional properties of these unique sensory cells. Here we describe a method for enzymatically isolating human cells from fungiform papillae obtained by biopsy and maintaining them in culture for more than 7 passages (7 months) without loss of viability and while retaining many of the functional properties of acutely isolated taste cells. Cells in these cultures exhibited increases in intracellular calcium when stimulated with perceptually appropriate concentrations of several taste stimuli, indicating that at least some of the native signaling pathways were present. This system can provide a useful model for molecular studies of the proliferation, differentiation, and physiological function of human fungiform papillae cells.

Resemblance of Tongue Anatomy in Twins

Twin Research and Human Genetics : the Official Journal of the International Society for Twin Studies. Jun, 2011  |  Pubmed ID: 21623658

This study compared the anatomical features of the tongue in nine pairs of twins - six monozygotic and three dizygotic. The aim of the project was to determine if tongues, like any other anatomical structure, could be used to reliably predict relatedness given that tongue shape, presentation and surface can be influenced by environment. Using the method of forced choice, 30 subjects were asked to match the photographs of tongues from twins. Our data indicate that, based on visual assessment, monozygotic twins have highly similar tongues (60% matches); similarly, dizygotic twins were matched 31% of the time, which is a higher probability than would be expected from random selection. This study should help identify baseline and control data in future behavioral studies of taste, which has a genetic basis.