bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Secretion of MCP-1 by Dental Follicle Cells-Implications for Tooth Eruption
Authors: Wise G.E. , Que B.G. , Huang H.
Published: January 2009

The monocyte chemotactic protein-1 (MCP-1) gene is expressed in the dental follicle, a loose connective tissue sac that must be present for eruption to occur. The role of MCP-1 may be to recruit mononuclear cells (monocytes) to the dental follicle, where these cells, in turn, fuse to form osteoclasts to resorb alveolar bone for the formation of an eruption pathway. Thus, it was the aim of this study to determine if MCP-1 is secreted by dental follicle cells in culture and if its secretion is enhanced by potential tooth eruption molecules. Western blotting and a two-site capture enzyme-linked immunoabsorbent assay demonstrated that MCP-1 was synthesized and secreted into the medium by the follicle cells. Incubation of the cells with either transforming growth factor-beta one (TGF-β1) or interleukin-one alpha (IL-la) enhanced the secretion of MCP-1 by the cells. Measurement of the chemotactic ability of the conditioned medium to attract mouse monocytes demonstrated that the chemotaxis of the medium was increased if the cells had previously been incubated in IL-la, although there appears to be a threshold concentration of MCP-1 above which chemotaxis is not enhanced. These combined results suggest that the critical initial cellular event of tooth eruption, an influx of mononuclear cells into the dental follicle at an early post-natal age, may be initiated by the secretion of MCP-1 by the dental follicle cells.
Reduced in vivo Cell-mediated Immune Responses to Mumps, Tuberculin, and Streptokinase/Streptodornase but not to Candida albicans in Oral Lichen Planus
Authors: Simark-Mattsson C. , Jontell M. , Bergenholtz G. , Dahlgren U.I.
Published: January 2009

Oral lichen planus is considered to be a T-cell-mediated disease. The purpose of this study was to investigate the capacity of T-lymphocytes in oral lichen planus patients to respond to a number of commonly encountered environmental antigens in vivo. To do this, we assessed dermal delayed-type hypersensitivity responses to mumps, streptokinase/streptodornase, Candida albicans, and purified protein derivative of tuberculin (PPD) in 17 oral lichen planus patients and in matched controls. Reduced induration in response toward mumps, PPD, and streptokinase/streptodornase was demonstrated in oral lichen planus patients compared with controls. In addition, the total sum of induration diameters was decreased in the patients. However, C. albicans stimulation resulted in similar levels of response in both groups. The differences in induration size between matched patients and controls for mumps and PPD were thus significantly greater than the corresponding differences for the C. albicans antigen. This suggests that a selective difference in the response to these antigens exists in oral lichen planus patients. The results may point to a loss of memory T-helper function to infrequently encountered environmental antigens, represented by mumps, PPD, and streptokinase/streptodornase, contrarily to memory function to common antigens (C. albicans), which seem to be unaffected.
Cold Pressor Stimulation Effect on Hemodynamic Changes Following Sustained Isometric Contraction in Human Jaw-closure Muscles
Authors: Tsukiyama Y. , Kuboki T. , Clark G.T.
Published: January 2009

It is postulated that an altered adrenergic response pattern may be associated with chronic muscle pain states. To evaluate this hypothesis, one must fully understand the effect of an adrenergic activation on masticatory muscle blood flow under various conditions. This study evaluated the effect of a 12°C cold pressor stimulation (a mild adrenergic activator), applied to the hand-forearm area, on intramuscular hemodynamics in the human masseter and temporalis muscles following a sustained isometric contraction. We assessed hemodynamics by measuring intramuscular hemoglobin concentration repeatedly, using a non-invasive near-infrared spectroscopy device. Measurements were taken before, during, and after a 30-second sustained 50% maximum voluntary contraction task. Fourteen healthy subjects, seven males and seven females, with no history of muscle pain in the masticatory system participated in this study. This protocol was repeated three times, but in the second trial, the cold pressor stimulation was applied to the subject during and for 5 min after the sustained contraction task. Repeated-measure analysis of variance performed on these data revealed that the peak hemoglobin concentration levels in the post-contraction recovery period were significantly reduced (between 13 and 14%) with cold pressor stimulation, both in the masseter (p < 0.001) and in the temporalis (p < 0.001) muscles. The results suggest that cold pressor stimulation produced a reduced intramuscular vasodilative response in these muscles during the immediate post-contraction period. One explanation for these results is that altering the local chemical environment of the muscle affects the adrenergic response pattern typically induced by a cold pressor stimulation.
Orthodontists' Perceptions of the Impact of Phase 1 Treatment for Class II Malocclusion on Phase 2 Needs
Authors: King G.J. , Wheeler T.T. , McGorray S.P. , Aiosa L.S. , Bloom R.M. , Taylor M.G.
Published: January 2009

The most appropriate timing for the treatment of Class II malocclusions is controversial. Some clinicians advocate starting a first phase in the mixed dentition, followed by a phase 2 in the permanent dentition. Others see no clear advantage to that approach and recommend that the entire treatment be done in the late mixed or early permanent dentition. This study examines how orthodontists, blinded to treatment approach, perceive the impact of phase 1 treatment on phase 2 needs. The sample consisted of 242 Class II subjects, aged 10 to 15, who had completed phase 1 or observation in a randomized clinical trial (RCT). For each subject, video orthodontic records, a questionnaire, a fact sheet, and a cephalometric tracing were sent to five randomly selected reviewing orthodontists blinded to subject group and study purpose. Reviewing orthodontists were asked to assess treatment need, general approach, need for extractions, priority, difficulty, and determinants. Orthodontists agreed highly on treatment need (95%) and moderately on treatment approach (84%) and extraction need (80%). They did not perceive differences in need, approach, or extractions between treated and control groups. Treated subjects were judged as less difficult (p = 0.0001) and to have a lower treatment priority (p = 0.0001) than controls. In ranking problems that affect treatment decisions, the orthodontists ranked dental Class II (p = 0.005) and skeletal relationships (p = 0.004) more highly in control than in treated patients. These data indicate that orthodontists do not perceive phase 1 treatment for Class II as preventing the need for a second phase or as offering any particular advantage with respect to preventing the need for extractions or other skeletal treatments in that second phase. They do view early Class II treatment as an effective means of reducing the difficulty of and priority for phase 2.
Association Between Extent of Periodontal Attachment Loss and Self-reported History of Heart Attack: An Analysis of NHANES III Data
Authors: Arbes S.J. , Slade G.D. , Beck J.D.
Published: January 2009

Coronary heart disease is responsible for one of every five deaths in the United States. Recent epidemiological studies have shown an association between periodontal disease and coronary heart disease. The purpose of this cross-sectional study was to verify this association using data from the third National Health and Nutrition Examination Survey (NHANES III). Data for 5564 people 40 years of age and older who had complete periodontal assessments and information on heart attack were evaluated. The outcome was the self-reported history of heart attack (yes vs. no). The main independent variable was the percent of periodontal sites per person with attachment loss of 3 mm or greater (categorized as 0%, > 0-33%, > 33-67%, and > 67%). Periodontal attachment loss was measured at two sites per tooth in randomly assigned half-mouths, one upper and one lower quadrant. The covariables included sociodemographic variables and established risk factors for cardiovascular disease. Relative to the 0% category, the unadjusted odds of heart attack increased with each higher category of attachment loss—2.2 (95% confidence interval = 1.3-3.8), 5.5 (3.4-9.1), and 9.8 (4.5-21.0), respectively. Adjustment for age, sex, race, poverty, smoking, diabetes, high blood pressure, body mass index, and serum cholesterol decreased these odds to 1.4 (0.8-2.5), 2.3 (1.2-4.4), and 3.8 (1.5-9.7), respectively. This study supports findings from previous studies of an association between periodontal disease and coronary heart disease.
The Intra-articular Distance within the TMJ during Free and Loaded Closing Movements
Authors: Huddleston Slater J.J.R. , Visscher C.M. , Lobbezoo F. , Naeije M.
Published: January 2009

Previous studies on free opening and closing movements of the mandible have demonstrated that the opening movement traces of the condylar kinematic center (i.e., the condylar point for which the protrusive and the opening movement traces coincide) lie closer to the articular eminence than the closing traces. This indicates the presence of an intra-articular distance within the joint during free closing. Since the mandible behaves like a class III biomechanical lever, a counteracting mechanical load on the mandible during closing will press the condyle-disc complex against the articular eminence. Therefore, in this study the hypothesis was tested that the difference between opening and closing movement traces of the kinematic center is reduced when the closing movements are counteracted by a mechanical load. From 10 healthy participants, 20-second movement recordings were obtained by a six-degrees-of-freedom opto-electronic jaw movement recording system (OKAS-3D) for three types of movements: (1) free opening and closing movements, (2) free opening and loaded closing movements (i.e., the participants closed against a small or high manually applied downward-directed force to the chin), and (3) gum chewing. Off-line, the opening and closing movement traces of the kinematic center were reconstructed, and the average difference between the traces (the intra-articular distance) was calculated. The average intra-articular distance was significantly smaller during loaded closing than during free closing, whereas no significant differences were found in the intra-articular distances between the loaded situations of low and high manual loading and contralateral chewing (ANOVA and post hoc Bonferroni multiple comparisons of means test, p < 0.005). In conclusion, loading of the mandible during closing movements reduces the intra-articular distance within the temporomandibular joint.
Optimization and Characterization of Pulp Extracted from the Agave Americana L. Fibers
Authors: Jaouadi Mounir , M'sahli Slah , Sakli Faouzi
Published: January 2009

The influence of temperature, pulping time and soda concentration on the yield, kappa index, brightness and fiber density of Agave Americana L. pulp has been studied. Using a factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the pulping process were established. The morphology of the cellulose fibers (length distribution, diameter distribution and crystalline index), obtained from the optimum pulping already determined by the statistical study, was determined by measuring 5020 fibers with optical microscopy equipped with CCD camera and image analysis software, and FT-IR spectra. Cellulose fibers extracted from Agave Americana L. had a lower lignin content value (1.13%) and an absorption capacity of 10.5 g/g. Finally, the characteristics of the optimum Agave pulp were compared to those of other vegetable fibers.
Reactive Dyes and Nano-Silver on PA6 Micro Knitted Goods
Authors: Gorenšek Marija , Recelj Petra
Published: January 2009

The goal of our research was to obtain uniformly dyed PA6 micro knitted goods with excellent wet fastness, good UPF, and antibacterial properties. Newly developed reactive dyes and 80 nm silver particles were used. The AATCC-Test method 183 was used for the calculation of UPF of PA6 micro knitting. ICP-AES analysis was used for the determination of silver. Antibacterial activity of nano-silver on PA6 knitted goods was determined according to ASTM Designation E 2149-01. The research showed uniformly dyed PA6 micro knitting with excellent wet fastness. Dyed PA6 micro reached a UPF range between 15 and 24. ICP-AES showed high absorbance of silver. PA6 micro knittings treated with 80 nm nano-silver have high antimicrobial effectiveness against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, but after 10 washings the property is lost. Changes of color were observed on dyed PA6 micro knitting treated with nano-silver.
A Study of Generating Yarn Thin Places of Murata Vortex Spinning
Authors: Zhuan Yong Zou  , Jian Yong Yu  , Long Di Cheng  , Wen Liang Xue
Published: January 2009

In Murata vortex spinning, fiber loss is an important cause of the generation of yarn thin areas. In this paper, based on the attenuation law of flow field inside the nozzle block, the force analysis of a separated fiber twined over the top exterior of a hollow spindle in a twisting chamber is carried out, and the movement of a separated fiber affected by a swirling current is discussed. We also present a simple analytical formation that determines the critical angular velocity of the open-end trailing fiber rotating around the hollow spindle, as a function of the length of the core fiber and fiber radius, as well as other parameters. The critical angular velocity can affect whether the leading end of the fiber is pulled out from the yarn trail or not, which can explain the generation of fiber loss and yarn. The critical angular velocity increases with increasing length of the core fiber and decreasing fiber radius. Above a certain nozzle pressure, the fiber radius is larger, there is greater fiber loss and there are a greater number of thin places in the vortex spun yarn. Increasing the nozzle pressure first enhances the yarn tenacity, and then generates more fiber loss and yarn thinning in places, and also causes a deterioration of the yarn properties when the nozzle pressure exceeds the critical point.
Thermal Comfort Properties of Wearing Caps from Various Textiles
Authors: Youngmin Jun  , Chung Hee Park  , Shim Huensup , Tae Jin Kang
Published: January 2009

The purpose of this research was to explore the effects of textile properties on the microclimate inside caps and on subjective wearing sensations. Physical tests on heat and moisture transfer properties of cap fabrics were conducted, as well as tests on the sensations from subjects wearing the caps. The temperature and humidity inside caps were influenced by the thickness, moisture retention properties, water absorption properties, and thermal conductivity of cap fabrics. High water absorbency property was the most important factor in lowering the temperature inside caps. Air permeability and water vapor transmission rate did not affect the microclimate. It seemed to be difficult for air or water vapors to move from the skin to the outer environment because the hair was densely packed between the skin and the cap, forming a stable air layer. Thermal sensation and thermal comfort were influenced by the thickness, water absorption properties, thermal conductivity, and Qmax of fabrics. Subjective sensations were closely related to the temperature inside caps. In the temperature range of 30 to 33°C, no change in wearing sensation was found. In the temperature range above 33°C, however, subjects started feeling uncomfortable.
Analysis of Polymeric Braided Tubular Structures Intended for Medical Applications
Authors: Yuksekkaya Mehmet E. , Adanur Sabi
Published: January 2009

In this study, monofilament tubular braided structures were fabricated and their performances were analyzed. The braided tubes are in three-dimensional form, made of polyester monofilaments intended for use in medical applications. This type of structure, called a stent, is used to open clogged arteries and veins by exerting radial forces. The radial force of a braided tube basically depends on three variables: braid angle, helical length, and braid diameter. The mandrel diameter influences the axial and radial forces obtained from the braid tube. In order to assure a stable structure, the braided fabrics were heat-set. Analysis of variances showed that heat-setting temperatures and heat-setting times of braided fabrics exhibited no significant effects in the range in which the tests were performed.
Within-person variability in state anxiety across adulthood: Magnitude and associations with between-person characteristics
Authors: Gerstorf Denis , Siedlecki Karen L. , Tucker-Drob Elliot M. , Salthouse Timothy A.
Published: January 2009

Across domains of functioning, research has shown substantial within-person variability in a number of different types of variables from one measurement occasion to another. Using data obtained from a large sample ( n = 784, 18—97 years) at three separate occasions, we examined properties and correlates of short-term variability in a construct that by definition is prone to fluctuations, namely state anxiety. Our results revealed that participants exhibited sizeable across-occasion variation in state anxiety. The magnitude of variability was unrelated to age, but was associated with a number of individual difference characteristics such as self-reported health, aspects of personality, well-being, and cognition. However, after taking into account mean-level differences in state anxiety, evidence for unique associations of variability was minimal.
Keeping it all inside: Shyness, internalizing coping strategies and socio-emotional adjustment in middle childhood
Authors: Findlay Leanne C. , Coplan Robert J. , Bowker Anne
Published: January 2009

Despite growing research results indicating that shyness is a risk factor for psychosocial maladjustment in childhood, less is known about the conceptual mechanisms that may underlie these associations. The purpose of the current study was to explore links between self-reported shyness, coping strategies and social functioning in middle childhood. As well, we sought to examine the reliance on internalizing coping strategies as a potential mediator of the link between shyness and social functioning. Participants were 355 children aged 9 to 11 years who completed measures of shyness, loneliness, positive and negative affect, social anxiety, self-concept, well-being, and coping strategies. Results indicated that shyness was associated with greater internalizing difficulties and lower well-being. Moreover, internalizing coping was found to partially mediate the relation between shyness and certain indices of internalizing problems. These results suggest a conceptual pathway, where an over-reliance on internalizing coping may partially explain why shy children experience internalizing difficulties in middle childhood.
Subjective age bias: A motivational and information processing approach
Authors: Teuscher Ursina
Published: January 2009

There is broad empirical evidence, but still a lack of theoretical explanations, for the phenomenon that most older people feel considerably younger than their real age. In this article, a measurement model of subjective age was assessed, and two independent theoretical approaches are proposed: (1) a motivational approach assuming that the age underestimation is a special form of self-enhancement; and (2) an information-processing approach assuming that elderly people look younger nowadays than formerly, which leads to an underestimation of their own age since people compare themselves to an age-prototype which is no longer accurate. Data from 792 adults aged 58—70 support the motivational approach, without ruling out the information processing approach. Data from a younger sample (42 students aged 20—35) provide evidence for the information processing approach additionally. Further, a path model suggests that bodily aspects are the strongest predictor of subjective age.
(Re)Constructing women's resistance to woman abuse: Resources, strategy choice and implications of and for public policy in Canada
Authors: Paterson Stephanie
Published: January 2009

While there has been considerable attention paid to Canada's anti-woman abuse policy framework, much of this attention has neglected its implications for women's resistance to abuse. This paper attempts to address this gap by using the lens of women's resistance to analyse the anti-woman abuse policy in Canada. I begin by exploring the ways in which the policy framework constructs the `problem' and considering its implications for women's choice in resistance strategy. Using the Canadian General Social Survey on Victimization (1999), I apply independent samples tests to explore women's (non)usage of various strategies, as it varies by class, race, and ability. I conclude with suggestions for policy reform.
`Starting Over'
Authors: Blackman Lisa
Published: January 2009

This review article explores the politics of hope and optimism made possible by a re-thinking of touch as a movement towards the not-yet-known, embodied through an engagement with the improvisational character of Argentine tango. Tango discloses the relational and enactive qualities of corporeality, moving us to ask not what bodies are, but rather what can bodies do; what can bodies become? The article engages with the moves to a Spinozist conception of affect developed by Massumi and Deleuze and Guattari, to consider the extent to which touch as affective symbiosis can form the basis of a democracy-yet-to-come. The article asks whether such concepts could and indeed should form the basis of a politics of re-invention, and what might be some of the problems and limitations with aligning affect principally with movement and change. The article situates the discussion within arguments that currently traverse the psychological and biological sciences, and concludes that more cautious reflection on the kinds of ontological turn that are forming the foundation of such processual models is needed.
The Recognition/Redistribution Debate and Bourdieu's Theory of Practice
Authors: Fowler Bridget
Published: January 2009

This review article takes up certain key issues that are at stake in the valuable collection of essays edited by Lovell. It considers critically the argument that the adoption of Fraser's perspectival dualism implies regression to a base—superstructure theory of the social. It assesses the advantages of extending the dualism of redistribution and recognition to include also the need for participatory parity in the post-Westphalian political order. It raises again the question of whether Honneth is sociologically more forceful than Fraser in arguing that material inequality is merely a facet of a more profound disrespect (lack of recognition). Lovell's assessment of Honneth's `recognition monism' is commended in that it resurrects an earlier critique of structural-functionalism to make a helpful distinction between social integration and (non-normative) system integration. She addresses these issues in terms of a wider critical realism concerned with disaggregating those social relations which are more causally generative from others: an approach which permits illuminating debates over the degree to which patriarchy and heteronormativity are contingent or necessary to late capitalism. Lovell also introduces Bourdieu into the debate, and especially his conceptions of misrecognition and symbolic violence. Finally, Sayer's vigorous arguments about the moral significance of distribution and class are considered as contributing to the current ethical turn. The article ends with an attempt to defend Bourdieu, whom Sayer sees both as a profound sociologist of class but also a theorist oriented too exclusively to agents' egoistic search for strategic advantage. The author concludes that although Fraser's perspectival trinity (or dualism) approach seems preferable to Honneth's monism, this should not obscure the empirical interweaving of deficiencies of distribution and of recognition in social reality. Indeed, new studies show the far-reaching consequences of this. In those societies where maldistribution is most marked, exposure to certain psychosocial risks such as low status (recognition) and low social capital literally incorporate stress, via biological pathways. Hence unequal health outcomes of a surprising range can also be detected.
Views of Sexual Abuse Professionals About Sex Offender Notification Policies
Authors: Levenson Jill S. , Fortney Timothy , Baker Juanita N.
Published: January 2009

This study examines the views of 261 sexual abuse professionals regarding sex crime policies. Few participants believe that community notification is very effective in reducing sex offenses, but about half believe that all sex offenders should be subject to public disclosure. About one quarter of respondents opine that sex offenders should not be allowed to live in their communities, but a majority do not view residential housing restrictions for sex offenders as effective at reducing recidivism. Most believe in the helpfulness of therapeutic intervention. More than half say that they will support sex offender policies even without scientific evidence of their effectiveness. Criminal justice professionals are more likely to approve of these laws compared to mental health professionals. Those with more conservative political leanings also favor more restrictive policies. There are few differences attributable to gender, parenting status, or victimization experiences.
In Vivo Evaluation of Butylene Terephthalate-ethylene Oxide-DL, Lactide Polymer as Porous Scaffolds for Tissue Engineering
Authors: Licheng Tan  , Yiwang Chen  , Yang Wang  , Weihua Zhou  , Xiangjun Zhu  , Xiaohui He  , Jiying Su  , Suping Cui
Published: January 2009

The copolymers of poly(1,4-butylene terephthalate-co-ethylene oxide-co-DL-lactide), obtained by the transesterification reactions of poly(butylenes terephthalate) with poly(ethylene glycol DL-oligo(lactic acid), were fabricated into porous scaffolds by the established solvent-casting and particulate-leaching technique with NaCl as the porogen. The morphology of the porous scaffolds were investigated by the scanning electron microscopy (SEM), and the pores within the scaffold were proven to be interconnective ranging in size from 200 to 400 μm. The human bone marrow mesenchymal stem cells (MSC) seeded on the scaffolds were confirmed to survive and proliferate within the pores of the scaffold with the observation by immunofluorescence microscope and SEM. In vivo implantation of MSC-seeded scaffolds into athymic nude mice showed significant tissue formation in the subcutaneous sites of the immunodeficient mice at 3, 4, 6, and 9 weeks. The results indicate that the scaffolds were biocompatible with MSC and the host tissue in vitro and in vivo.
Three-dimensional Cultures of Rat Pancreatic RIN-5F Cells in Porous PLGA-collagen Hybrid Scaffolds
Authors: Kawazoe Naoki , Xiaoting Lin  , Tateishi Tetsuya , Guoping Chen
Published: January 2009

Three-dimensional cultures of pancreatic islet cells in porous scaffolds or hydrogels have been constructed as a biohybrid artificial pancreas. A thin mesh of a PLGA-collagen hybrid was used to culture rat RIN-5F cells. The hybrid mesh was coated with laminin, fibronectin, vitronectin, type IV collagen, and poly(L-lysine) were evaluated and mesh without coating was used as a control. Cell adhered and proliferated on all of the coated and uncoated meshes. The cells formed spheroids in the uncoated, poly(L-lysine)-, fibronectin-, vitronectin-, and type IV collagen-coated hybrid meshes, while forming a layered structure in the laminin-coated hybrid mesh. Cell adhesion on the coated PLGA-collagen hybrid meshes was higher than that for the uncoated hybrid mesh. The laminin-coated hybrid mesh showed the greatest level of adhesion. The insulin secretion capacity of RIN-5F cells was at the same level for all coated and uncoated PLGA-collagen hybrid meshes and higher than that of cells cultured on cell culture plates. The 3D cultured PLGA-collagen hybrid meshes promoted insulin production capacity. Gene expression analysis showed that genes encoding insulin I, insulin II, and the pancreatic transcription factor PDX-1 (pancreas/duodenum homeobox 1) was expressed. These results indicate that the PLGA-collagen hybrid meshes support adhesion, proliferation, and differentiation of RIN-5F cells that allows culturing pancreatic islet cells on 3D constructs.
Separating the Men from the Moms
Authors: Messner Michael A. , Bozada-Deas Suzel
Published: January 2009

Based on a multiyear study, this article analyzes the reproduction of adult gender segregation in two youth-sports organizations in which most men volunteers become coaches and most women volunteers become “team moms.” We use interviews and participant observation to explore how these gender divisions are created. While most participants say the divisions result from individual choices, our interviews show how gendered language, essentialist beliefs, and analogies with gendered divisions of labor in families and work-places naturalize this division of labor. Observation reveals how patterned, informal interactions reproduce (and occasionally challenge) it as well. We show how (mostly) nonreflexive informal interactions at the nexus of three gender regimes—youth sports, families, and workplaces—produce a gender formation with two interrelated characteristics: an ascendant professional class gender ideology that we call “soft essentialism” and a “gender category sorting system” that channels most men into coaching and most women into being “team moms.”
Xerostomia and Hyposalivation
Authors: Nederfors T.
Published: January 2009

Dry mouth must not be considered a trivial problem in the population, since it constitutes a phenomenon with many aspects relative to oral function as well as quality of life. Up until today, no global consensus has been reached with regard to the terminology of dry mouth, creating a substantial problem for research, education, diagnosis, and therapy. In this report, salivary gland hypofunction has been selected as the overarching term for subjective symptoms and objective signs of dry mouth. Its different aspects-xerostomia, hyposalivation, and altered saliva composition-are reviewed with respect to prevalence, diagnosis, and etiology. It is concluded that these aspects of salivary gland hypofunction are separate entities, which in many respects are interrelated, constituting not merely a dental but also a medical and social concern.
What Can Transgenic and Gene-targeted Mouse Models Teach Us about Salivary Gland Physiology?
Authors: Melvin J.E. , Nguyen H.-V. , Evans R.L. , Shull G.E.
Published: January 2009

Thousands of genetically modified mice have been developed since the first reports of stable expression of recombinant DNA in this species nearly 20 years ago. This mammalian model system has revolutionized the study of whole-animal, organ, and cell physiology. Transgenic and gene-targeted mice have been widely used to characterize salivary-gland-specific expression and to identify genes associated with tumorigenesis. Moreover, several of these mouse lines have proved to be useful models of salivary gland disease related to impaired immunology, i.e., Sjogren's syndrome, and disease states associated with pathogens. Despite the availability of genetically modified mice, few investigators have taken advantage of this resource to better their understanding of salivary gland function as it relates to the production of saliva. In this article, we describe the methods used to generate transgenic and gene-targeted mice and provide an overview of the advantages of and potential difficulties with these models. Finally, using these mouse models, we discuss the advances made in our understanding of the salivary gland secretion process.
Adrenoceptor-activated Nitric Oxide Synthesis in Salivary Acinar Cells
Authors: Looms D.K. , Dissing S. , Tritsaris K. , Pedersen A.M. , Nauntofte B.
Published: January 2009

We investigated the cellular regulation of nitric oxide synthase (NOS) activity in isolated acinar cells from rat parotid and human labial salivary glands, using the newly developed fluorescent nitric oxide (NO) indicator, DAF-2. We found that sympathetic stimulation with norepinephrine (NE) caused a strong increase in NO synthesis that was not seen after parasympathetic stimulation with acetylcholine. In rat parotid acinar cells, we furthermore investigated to which extent the NOS activity was dependent on the intracellular free Ca2+ concentration ([Ca2+]i) by simultaneously measuring NO synthesis and [Ca2+]i. It was found that a simple correlation between the rise in [Ca2+]i and the rate of NO production following NE stimulation does not exist, and studies in which [Ca2+]i was elevated by means of the Ca 2+ ionophore, ionomycin, further established that even a very large rise in [Ca2+]i did not cause significant NO synthesis. We furthermore found that activating adrenoceptors with NE causes synthesis of cGMP by activating a guanylyl cyclase, and that an enhanced [cGMP] evoked by use of caged cGMP causes Ca2+ release from internal stores. Thus, upon sympathetic stimulation, salivary gland acini synthesize NO that, in addition to playing a role in controlling intracellular [Ca2+] i' also might play a role in retrograde signaling processes to the surrounding tissue.
Enamel Knots as Signaling Centers Linking Tooth Morphogenesis and Odontoblast Differentiation
Authors: Thesleff Irma , Keranen Soile , Jernvall Jukka
Published: January 2009

Odontoblasts differentiate from the cells of the dental papilla, and it has been well-established that their differentiation in developing teeth is induced by the dental epithelium. In experimental studies, no other mesenchymal cells have been shown to have the capacity to differentiate into odontoblasts, indicating that the dental papilla cells have been committed to odontoblast cell lineage during earlier developmental stages. We propose that the advancing differentiation within the odontoblast cell lineage is regulated by sequential epithelial signals. The first epithelial signals from the early oral ectoderm induce the odontogenic potential in the cranial neural crest cells. The next step in the determination of the odontogenic cell lineage is the development of the dental papilla from odontogenic mesenchyme. The formation of the dental papilla starts at the onset of the transition from the bud to the cap stage of tooth morphogenesis, and this is regulated by epithelial signals from the primary enamel knot. The primary enamel knot is a signaling center which forms at the tip of the epithelial tooth bud. It becomes fully developed and morphologically discernible in the cap-stage dental epithelium and expresses at least ten different signaling molecules belonging to the BMP, FGF, Hh, and Wnt families. In molar teeth, secondary enamel knots appear in the enamel epithelium at the sites of the future cusps. They also express several signaling molecules, and their formation precedes the folding and growth of the epithelium. The differentiation of odontoblasts always starts from the tips of the cusps, and therefore, it is conceivable that some of the signals expressed in the enamel knots may act as inducers of odontoblast differentiation. The functions of the different signals in enamel knots are not precisely known. We have shown that FGFs stimulate the proliferation of mesenchymal as well as epithelial cells, and they may also regulate the growth of the cusps. We have proposed that the enamel knot signals also have important roles, together with mesenchymal signals, in regulating the patterning of the cusps and hence the shape of the tooth crown. We suggest that the enamel knots are central regulators of tooth development, since they link cell differentiation to morphogenesis.
Molecular Insights into the Lineage-specific Determination of Odontoblasts: The Role of Cbfa1
Authors: Gaikwad J.S. , Hoffmann M. , Cavender A. , Bronckers A.L.J.J. , D'Souza R.N.
Published: January 2009

The role of stable transcription complexes in initiating and consolidating programs of gene expression during lineage specification has been extensively studied. Despite the progress made in the identification of key molecules of tooth initiation and patterning, the mechanisms leading to cell differentiation during odontogenesis are unknown. Odontoblasts are exclusive dentin-producing cells that are phenotypically and functionally distinct from osteoblasts. However, not much is known about the precise determinants of odontoblast terminal differentiation-in particular, how the fate of these cells becomes delineated from that of osteogenic mesenchyme. Cbfa1(-/-) mice completely lack osteoblasts and bone, while tooth development arrests at the time of odontoblast differentiation. The purpose of this paper is to overview our studies on the role of Cbfa1 in odontoblast determination and differentiation using the Cbfa1(-/-) mouse model and various experimental approaches. Our expression analyses confirm the down-regulation of Cbfal expression in newly differentiated and functional odontoblasts. Second, we demonstrate that Cbfa1(-/-) incisor organs arrest at a later stage than molars, and that al(I) :ollagen, a marker of odontoblast differentiation shared in common with osteoblasts, is not significantly affected by the absence of the transcription factor. Interestingly, Dspp expression in Cbfa1(-/-) appeared markedly down-regulated in putative odontoblasts. The overexpression of Cbfa1 in an odontoblast cell line (MDPC-23) results in the selective down-regulation of Dspp and not type I collagen. It is likely that, in addition to its influence on tooth epithelial morphogenesis, Cbfa1 plays a non-redundant and stage-specific role in the lineage determination and terminal differentiation of odontoblasts from dental papilla mesenchyme.
New Genes Involved in Odontoblast Differentiation
Authors: Bleicher F. , Couble M.L. , Buchaille R. , Farges J.C. , Magloire H.
Published: January 2009

The odontoblast phenotype has been mainly approached by the biochemical characterization of dentin matrix proteins and by extrapolation of the knowledge of bone cell biology, since dentin and bone share many similarities. In fact, direct investigations of the odontoblast phenotype have been hindered by the limited number of cells within the dental pulp and the difficulty in microdissection and isolation of a pure population of these cells. To overcome these obstacles, we previously developed a cell-culture system that promotes differentiation of human dental pulp cells into odontoblasts. This material now permits the study of odontoblasts through molecular biology techniques. Therefore, we constructed a cDNA library enriched for odontoblast-specific genes using the suppression subtractive hybridization technique (SSH). This library led us to identify new genes expressed by odontoblasts. In this paper, we will focus on some genes implied in various functions associated with odontoblast differentiation, such as cell polarization (MAP1B), dentin mineralization (PHEX, osteoadherin), and relationships between odontoblasts and nerve cells (reelin). Another important fact is that about 40% of the cDNA were unknown genes. Therefore, one can speculate that some of them will be odontoblast-specific, since, until now, only one gene (DSPP) presents this characteristic.
Adding Fluoride to Sugar—a New Avenue to Reduce Dental Caries, or a "Dead End"?
Authors: Bratthall D. , Barmes D.E.
Published: January 2009

A study group was formed in 1989 by the Oral Health Program of WHO, Geneva, to consider the possibility of reducing dental caries by adding fluoride to sugar. Although a few promising clinical reports were available for review, the group found that information was too scarce for field trials to be recommended at this stage. Among the many items to be considered was what concentration of fluoride in sugar could reasonably be regarded as cariostatic. Thus, the committee decided to initiate studies to obtain further background information. Unlike fluoridated salt, the concept of fluoridated sugar does not involve trying to give the individual a certain daily amount of fluoride, since daily consumption varies considerably. Instead, the idea is to elaborate on recent fluoride research showing that low concentrations of fluoride may also be beneficial, particularly for remineralization, if present at the sites where caries occurs.

This paper is an introduction to a set of papers describing the background for the project, attempting to define optimal concentrations for a clinical trial, and concluding that, although dental caries prevalence continues to decrease in industrialized countries, the potential for large increases remains in the huge populations in developing countries. All avenues must be searched for a system which optimizes preventive efficiency. However, the possible introduction of fluoridated sugar on the market is not related only to oral health. Safety aspects are of high priority, and several ethical, political, and economic factors must also be considered. These papers attempt to present the issue for broad discussion and to stimulate researchers to conduct further studies which can guide decisions on whether fluoridated sugar may be an avenue worth testing on a broader scale, or whether the idea should be abandoned.
Proteases and Collagenases of Porphyromonas Gingivalis
Authors: Kuramitsu H.K. , Yoneda M. , Madden T.
Published: January 2009

Proteases expressed by Porphyromonas gingivalis have been considered as potential virulence factors for these periodontopathic micro-organisms. The introduction of molecular genetic approaches to study these enzymes has clearly demonstrated that these organisms are capable of expressing multiple distinct proteases. Several of these enzymes are apparently expressed as active proteolytic products following processing of larger precursor proteins. In addition, more recent data have suggested a close relationship between some of these enzymes and two other potential virulence factors of these organisms: hemagglutinins and collagenases.
Characteristics of Actinobacillus Actinomycetemcomitans Invasion of and Adhesion to Cultured Epithelial Cells
Authors: Fives-Taylor P. , Meyer D. , Mintz K.
Published: January 2009

Actinobacillus actinomycetemcomitans (A.a.) is highly implicated in periodontitis. We have developed several in vitro models using the KB oral cell line to examine A.a.-epithelial cell interactions. In support of the use of KB cell line model systems is our finding that A.a. invaded KB and primary gingival cells to the same extent. Invasion is an active event which requires new protein synthesis by both KB and A.a. Like many other intracellular parasites, A.a. invade by receptor-mediated endocytosis. We observed that internalized A.a. were surrounded by foci of actin which had been transported from the periphery of the KB cell. Adhesion of A.a. to KB cells occurred rapidly and stimulated the formation of microvilli. Adhesion is affected by both host factors (saliva, serum, [NaCI]) and culture conditions. Multiple determinants [fimbriae, outer membrane proteins, vesicles, and/or an extracellular amorphous material (ExAmMat)] which are either associated with the A.a. surface or are released into the milieu are involved. We determined that ExAmMat can convey adhesiveness to weakly adherent A.a. and to at least one other oral species (Streptococcus parasanguis).
Effects on Demineralization of Enamel by Fluoridated Sucrose: A Pilot Study in an in Situ Caries Model
Authors: Carlsson P. , Angmar-Mansson B. , Redmo-Emanuelsson I.-M. , Anderssén K.
Published: January 2009

Blocks of human enamel, placed in removable partial dentures, were allowed to acquire natural plaque for seven days and were exposed extra-orally to a cariogenic challenge by repeated periods in a fluoride-sucrose solution. As a control, enamel blocks were exposed extra-orally to a sucrose solution. After two weeks of cariogenic challenge, the blocks were examined for mineral loss by quantitative microradiography on thin sections of the enamel. The results from six subjects showed that no significant effect on demineralization could be detected by the addition of fluoride corresponding to fluoride/sugar content of 1 mg/kg, 5 mg/kg, or 10 mg/kg (dry weight). One subject did not develop lesions at all, either with fluoride-sucrose or with sucrose exposure alone.
Some Operational Aspects of School-Milk Fluoridation in St. Helens, Merseyside, UK
Authors: Lennon M.A. , Jones S. , Woodward S.M.
Published: January 2009

St. Helens is a small industrial town situated about 20 km east of Liverpool. It lies in an area of social deprivation and, by UK standards, dental caries experience is high (e.g., dmft at 5 years = 2.8; DMFT at 12 years = 2.7). Water fluoridation is an important part of the government's strategy for improving oral health in such areas; however, in large parts of St. Helens, implementation of water fluoridation is complicated by reason of the multiple sources of water supply. The aims of the St. Helens study are therefore to examine the technical, organizational, and legal aspects of the fluoridation of school milk as an alternative public health approach. In the UK, children attending nursery units (kindergartens) from ages 2-4 years and infant schools from ages 4-7 years are eligible for 189 mL of milk to be consumed each day at school. These two schemes are funded or subsidized by the Departments of Health (UK) or the European Community, respectively. A preliminary review of the possibility of using school milk as a vehicle for fluoride has been published recently (Jones et al., 1992). The current paper will review progress over the past 12 months, including the response of schools, dairies, and other organizational considerations.
Early Diagnosis and Prevention of Oral Cancer and Precancer: Report of Symposium III
Authors: Chairman T.Axéll , Downer M.C.
Published: January 2009

Oral precancer encompasses several conditions and lesions. Among those entities included in the concept are leukoplakia, erythroplakia, lichen planus, and submucous fibrosis. For prevention, knowledge about etiologic and pathogenetic factors is imperative. It is well-known that excessive consumption of tobacco and alcohol has a bearing on the development of oral leukoplakia and probably also of erythroplakia. However, among leukoplakias, the idiopathic or cryptogenic type probably shows the most serious malignant potential. Involved in the development of such lesions may be general nutritional aspects, e.g., proper utilization of vitamin A. It is also well-known that iron deficiency has been linked to Plummer-Vinson's syndrome, showing a precancerous trait. Among factors involved in the pathogenesis of lichen planus is probably mental stress. Thus, stress factors and related neurological components have been linked to the immunological system. Lifestyle factors, such as nutrition, tobacco, and alcohol, and also mental environment may be of importance for the development of oral precancer and cancer.