bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell-Mediated Immune System Regulation in Periodontal Diseases
Authors: Mathur A. , Michalowicz B.S.
Published: January 2009

The adaptive immune system consists of humoral and cell-mediated immunity. T-lymphocytes are the key components of cell-mediated immunity. CD4+ helper T-lymphocytes facilitate B-cells to differentiate and produce specific antibodies, whereas CD8+ cytotoxic T-lymphocytes kill virally infected cells. Periodontal diseases have been associated with a variety of imbalances in the regulation of immune responses. Changes in the ratios of peripheral blood CD4+ and CD8+ T-lymphocytes, depressed proliferative responses of peripheral blood lymphocytes, and increased frequency of CD45RO+ memory T-lymphocytes in diseased tissues have been reported in individuals with various forms of periodontal disease. While some studies have shown an increased frequency of γδ+ T-cells in periodontal lesions, the role of γδ+ T-cells in periodontal disease remains controversial. The ability of putative periodontopathic bacteria selectively to stimulate certain V(3-expressing T-cells is intriguing and could determine whether a CD4+ Th I or a CD4+ Th2 cell response is elicited. The prominence of a particular subset of helper T-cells within the periodontal lesion could be a reflection of the stage and activity of the disease, or the types of bacteria present. Regardless, longitudinal studies of the involvement of T-cell subsets and cytokines in periodontal disease are clearly needed.
Modeling the Mechanical Behavior of the Jaws and Their Related Structures By Finite Element (Fe) Analysis
Authors: Korioth T.W.P. , Versluis A.
Published: January 2009

In this paper, we provide a review of mechanical finite element analyses applied to the maxillary and/or mandibular bone with their associated natural and restored structures. It includes a description of the principles and the relevant variables involved, and their critical application to published finite element models ranging from three-dimensional reconstructions of the jaws to detailed investigations on the behavior of natural and restored teeth, as well as basic materials science. The survey revealed that many outstanding FE approaches related to natural and restored dental structures had already been done 10-20 years ago. Several three-dimensional mandibular models are currently available, but a more realistic correlation with physiological chewing and biting tasks is needed. Many FE models lack experimentally derived material properties, sensitivity analyses, or validation attempts, and yield too much significance to their predictive, quantitative outcome. A combination of direct validation and, most importantly, the complete assessment of methodical changes in all relevant variables involved in the modeled system probably indicates a good FE modeling approach. A numerical method for addressing mechanical problems is a powerful contemporary research tool. FE analyses can provide precise insight into the complex mechanical behavior of natural and restored craniofacial structures affected by three-dimensional stress fields which are still very difficult to assess otherwise.
Is Fibroblast Heterogeneity Relevant To the Health, Diseases, and Treatments of Periodontal Tissues?
Authors: Lekic P.C. , Pender N. , McCulloch C.A.G.
Published: January 2009

There are wide variations of gene expression and strikingly different responses to extracellular signals among different fibroblast populations. This has prompted a large number of in vitro studies which suggest that fibroblasts are not homogeneous but instead comprise multiple subpopulations with extensive site-to-site and intra-site variations. Conceivably, either fibroblasts are not all created equal, or, alternatively, discrete subpopulations may emerge in development, inflammatory lesions, or wound healing. While the heterogeneous nature of cultured fibroblasts has been known for some time, are these variations relevant to our understanding of the biology of oral tissues, their involvement in disease, and their response to therapy? Since fibroblasts are the predominant cell type in soft connective tissue matrices, the regulation of their proliferative, synthetic, and degradative behavior is likely to be important in tissue physiology and pathology. In this review, we use the current literature to assess whether fibroblast subpopulations really make a difference in the health and disease of periodontal tissues. We address the following questions: ( 1 ) Is fibroblast heterogeneity a real in vivo phenomenon? (2) How can we advance our knowledge of phenotypic variations and the regulation of fibroblast differentiation? (3) Could a knowledge of fibroblast heterogeneity have an impact on the development of new approaches to pathogenesis and the treatment of periodontal tissues?
Epidemiology of Temporomandibular Disorders: Implications for the Investigation of Etiologic Factors
Authors: LeResche L.
Published: January 2009

Epidemiology is the study of the distribution, determinants, and natural history of disease in populations. Epidemiology has several uses in addition to its traditional role of documenting the public health significance of a condition. Notably, epidemiologic methods and data can be used to identify and verify causes of disease. This article reviews the epidemiologic data on pain in the temporomandibular region, and on signs and symptoms associated with specific subtypes of temporomandibular disorders, with the aim of identifying possible etiologic factors for these conditions that deserve further study. Despite methodologic and population differences, several consistencies are apparent in the epidemiologic literature. Pain in the temporomandibular region appears to be relatively common, occurring in approximately 10% of the population over age 18; it is primarily a condition of young and middle-aged adults, rather than of children or the elderly, and is approximately twice as common in women as in men. This prevalence pattern suggests that etiologic investigations should be directed at biologic and psychosocial factors that are more common in women than in men, and diminish in older age groups. Most signs and symptoms associated with particular temporomandibular disorders (e.g., joint sounds, pain in the joint) also appear to be more prevalent in women than in men, although age patterns for these signs and symptoms are not as clear as for temporomandibular pain. The available data highlight the need for further research on etiologic factors associated with temporomandibular pain and with specific diagnostic subtypes of temporomandibular disorders.
Periodontal Probing
Authors: Hefti Arthur F.
Published: January 2009

For decades, probing clinical pocket depth and attachment level have been recognized as the dentist's most important tools in diagnosing periodontal health and disease. They are physical methods to measure the distance from the bottom of a pocket to a reference line, usually the gingival margin or the cemento-enamel junction. Probing accuracy and precision are affected by factors like the design of the probe, probing force, probe position, pocket depth, or tissue inflammation. Recently, several new electronic periodontal probes have been developed. They feature high instrument precision, allowing for measurements to the nearest tenth of a millimeter. They control for probing force and permit data to be collected and stored electronically. The purpose of this review paper is to summarize various aspects of periodontal probing. First, the history of periodontal probes will be briefly recollected, and interesting and significant inventions of the past and the present emphasized. Then, the importance of the periodontal tissues relative to probe tip penetration will be reviewed, and the probing performance will be discussed. The paper will conclude with notes on selected statistical issues.
Phosphorylation of the Proteins of the Extracellular Matrix of Mineralized Tissues By Casein Kinase-Like Activity
Authors: Veis Arthur , Sfeir Charles , Chou Bing Wu
Published: January 2009

The extracellular matrix of the connective tissue contains non-collagenous proteins (NCP) which are acidic in character. The NCP of mineralizing systems (bone, dentin) differ from those of the non-mineralizing systems (skin, tendon) in that the mineralized tissue NCP are frequently phosphorylated. The phosphorylated proteins have been implicated in various aspects of the mineralization process. Thus, it is of interest to consider the mechanism and regulation of phosphorylation of the major matrix NCP. The majority of the phosphorylation takes place at Ser or Thr residues embedded within acidic sequences, and therefore are targets for casein kinase I (CK1) or casein kinase II (CK2)-like kinases. CK1 and CK2 are distantly related members of the protein kinase family. They are ubiquitous, constitutively active, second-messenger-independent kinases. CK1 is found in a variety of isoforms, all homologous to the a-subunit of the protein kinase family. It acts as a monomer. The active form of CK2 is a tetrameric holoenzyme, with 2 a catalytic subunits and 2 β regulatory subunits. The CK2 a has activity alone, but the holoenzyme is four- to five-fold that activity. CK2 can use either ATP or GTP as the phosphate donor, but CK I can use only ATP. The CK2 activity which phosphorylates the mineralized tissue NCP appears to be localized to membrane-associated cell fractions, and is present in the endoplasmic reticulum and Golgi compartments in osteoblasts, where phosphorylation of the secreted proteins appears to take place as co- and post-translational processes. Data indicate that both a and β subunits of the membrane-associated CK2 are isoforms of the cytosolic CK2 in the same cells. The CK1 has not been specifically localized. Studies of dephosphorylated NCP such as phosphophoryn (PP) have shown that CK1 will not phosphorylate dephosphorylated dPP unless prior phosphorylation with CK2 has been carried out. In turn, CK2 activity may be initiated only after an initial phosphorylation of one of the messenger-dependent kinases. Thus, the phosphorylation reactions in mineralized tissues may be a tightly regulated hierarchical or sequential cascade of intracellular phosphorylation events.
Psychosocial Factors and Secretory Immunoglobulin A
Authors: Valdimarsdottir Heiddis B. , Stone Arthur A.
Published: January 2009

This review focuses on studies that have examined the relation between psychosocial factors and secretory immunoglobulin A (s-IgA). Several studies have examined the relation between s-IgA and stressful circumstances ranging from major life events to minor daily events. The findings from these studies were often contradictory, since different experimenters reported different stress-related changes in s-IgA. The effects of stress reduction interventions, such as relaxation and imagery, on s-IgA levels have also been examined. Although these studies indicate that various interventions are associated with increases in s-IgA levels, methodological refinements are needed before more definitive conclusions can be made. The possibility that the relation between stress and s-IgA may be moderated by personality characteristics or mediated by psychological distress was supported in some studies. The review concludes with suggestions for future research.
Immune Defense Mechanisms of the Dental Pulp
Authors: Jontell M. , Okiji T. , Dahlgren U. , Bergenholtz G.
Published: January 2009

Defense reactions of the dentin/pulp complex involve a variety of biological systems, in which the immune system plays a pivotal role. The knowledge of the organization and function of pulpal immunocompetent cells has been sparse, but in recent years a significant body of information of immune mechanisms in general has provided a footing for substantial new knowledge of the immune mechanisms of the dental pulp. The identification of pulpal dendritic cells (DCs) has generated research activities which have led to a concept of how an antigenic challenge may evoke a pulpal inflammatory response. Although DCs are not able to identify foreign antigens specifically, they provide necessary signals to activate T-lymphocytes which in turn will orchestrate other immunocompetent cells to mount the local immune defense of the dental pulp. The purpose of this review is to accent the organization and function of pulpal DCs and other tissue and cellular components and to provide a basis for how they may interact to instigate pulpal defense mechanisms.
Is All Bone the Same? Distinctive Distributions and Properties of Non-Collagenous Matrix Proteins in Lamellar Vs. Woven Bone Imply the Existence of Different Underlying Osteogenic Mechanisms
Authors: Gorski J.P.
Published: January 2009

The purpose of this review is to summarize recent functional and structural findings regarding non-collagenous matrix proteins in bone and teeth, to compare gene locations for bone and tooth matrix proteins with loci for hereditary skeletal diseases, and to present several provocative hypotheses which integrate this new information into a physiological context. Hypothesis 1 proposes that the molecular composition of rapidly deposited and mineralized woven bone, as well as the responsiveness of cells synthesizing woven bone to stimuli, is different from that for more slowly synthesized lamellar bone, implying the existence of distinctive osteogenic mechanisms. This review of recent research strongly supports this proposal. Briefly, the protein composition of woven bone matrix is enriched in acidic phosphoproteins BAG-75 and BSP, which are not expressed in lamellar bone, which is itself enriched in osteocalcin. De novo deposition and mineralization of woven bone occurs faster than in lamellar bone by means of a matrix-vesicle-assisted mechanism. Deposition of woven bone occurs at sites experiencing biomechanical strains higher than those experienced by lamellar bone. In addition, woven bone in metaphyseal regions is more susceptible to osteoclastic resorption after space flight, ovariectomy, and loss of weightbearing than is lamellar bone. Finally, osteoprogenitor cells responsive to parathyroid hormone reside in the metaphyseal region of long bones. Taken together, these findings suggest that Hypothesis I represents a useful paradigm for future studies.

Specific functions mediated by most individual bone and tooth matrix proteins remain uncertain A review of current literature suggests that the functionality of skeletal matrix proteins is expressed through specific binding sites composed of particular species-conserved structural motifs (Hypothesis 2). Examples include the previously recognized Asp-Ser-Ser motif of dentin phosphophoryns and the gamma-carboxyglutamic acid motif of matrix GLA protein and osteocalcin. A new polyacidic amino acid motif composed of consecutive Asp and Glu residues (n > 7) was defined in extracellular matrix components osteopontin, bone sialoprotein, and bone acidic glycoprotein-75 on the basis of strong functional analogies with similar polyacidic stretches in divalent metal storage proteins of the endoplasmic reticulum and sarcoplasmic reticulum. These structural motifs represent prime targets for future structure-function studies in vivo and in vitro.
Epithelial Antimicrobial Peptides: Review and Significance for Oral Applications
Authors: Weinberg A. , Krisanaprakornkit S. , Dale B.A.
Published: January 2009

Epithelial tissues provide the first line of defense between an organism and the environment. Disruption of this barrier leads to bacterial invasion and subsequent inflammation. This is precisely the situation existing in the human oral cavity, where tissues are constantly exposed to a variety of microbial challenges that can lead to bacterially induced periodontal diseases, and to infections of the oral mucosa by bacteria, fungi, and viruses. With the recent discoveries of host-derived peptide antibiotics in mammalian mucosal epithelium, a new line of investigation is emerging to test the hypothesis that one class of these peptides, called " β-defensins", functions to protect the host against microbial pathogenesis at these critical, confrontational sites. In that light, impairment of β-defensin activity has recently been implicated in chronic bacterial infections in cystic fibrosis patients. The first direct evidence of expression of defensin peptides in the oral mucosa was the identification of a novel epithelial β-defensin in mammalian tongue. It was shown to be upregulated in inflammation, suggesting that it participates in host defense. It is theorized that epithelial cell-derived antimicrobial peptides function to keep the natural flora of micro-organisms in a steady state in different niches such as the skin, the intestines, the airway, the endocervix, and the mouth. There is now evidence indicating that normal gingival epithelial cells and tissues express two β-defensins, hBD- I and the newly described hBD-2. In addition, a cathelin-class antimicrobial peptide, designated LL-37 and found in human neutrophils, is also expressed in skin and gingiva. It is highly likely that these and/or other epithelial antimicrobial peptides play an important role in determining the outcome of the host-pathogen interaction at the oral mucosal barrier, and that they may have important future applications in antibiotic treatment.
Protein N-Glycosylation: Molecular Genetics and Functional Significance
Authors: Kukuruzinska M.A. , Lennon K.
Published: January 2009

Protein N-glycosylation is a metabolic process that has been highly conserved in evolution. In all eukaryotes, N-glycosylation is obligatory for viability. It functions by modifying appropriate asparagine residues of proteins with oligosaccharide structures, thus influencing their properties and bioactivities. N-glycoprotein biosynthesis involves a multitude of enzymes, glycosyltransferases, and glycosidases, encoded by distinct genes. The majority of these enzymes are transmembrane proteins that function in the endoplasmic reticulum and Golgi apparatus in an ordered and well-orchestrated manner. The complexity of N-glycosylation is augmented by the fact that different asparagine residues within the same polypeptide may be modified with different oligosaccharide structures, and various proteins are distinguished from one another by the characteristics of their carbohydrate moieties. Furthermore, biological consequences of derivatization of proteins with N-glycans range from subtle to significant. in the past, all these features of N-glycosylation have posed a formidable challenge to an elucidation of the physiological role for this modification. Recent advances in molecular genetics, combined with the availability of diverse in vivo experimental systems ranging from yeast to transgenic mice, have expedited the identification, isolation, and characterization of N-glycosylation genes. As a result, rather unexpected information regarding relationships between N-glycosylation and other cellular functions-including secretion, cytoskeletal organization, proliferation, and apoptosis-has emerged. Concurrently, increased understanding of molecular details of N-glycosylation has facilitated the alignment between N-glycosylation deficiencies and human diseases, and has highlighted the possibility of using N-glycan expression on cells as potential determinants of disease and its progression. Recent studies suggest correlations between N-glycosylation capacities of cells and drug sensitivities, as well as susceptibility to infection. Therefore, knowledge of the regulatory features of N-glycosylation may prove useful in the design of novel therapeutics. While facing the demanding task of defining properties, functions, and regulation of the numerous, as yet uncharacterized, N-glycosylation genes, glycobiologists of the 21st century offer exciting possibilities for new approaches to disease diagnosis, prevention, and cure.
The Developmental Control of Osteoblast-Specific Gene Expression: Role of Specific Transcription Factors and the Extracellular Matrix Environment
Authors: Franceschi R.T.
Published: January 2009

Bone formation is a carefully controlled developmental process involving morphogen-mediated patterning signals that define areas of initial mesenchyme condensation followed by induction of cell-specific differentiation programs to produce chondrocytes and osteoblasts. Positional information is conveyed via gradients of molecules, such as Sonic Hedgehog that are released from cells within a particular morphogenic field together with region-specific patterns of hox gene expression. These, in turn, regulate the localized production of bone morphogenetic proteins and related molecules which initiate chondrocyte- and osteoblast-specific differentiation programs. Differentiation requires the initial commitment of mesenchymal stem cells to a given lineage, followed by induction of tissue-specific patterns of gene expression. Considerable information about the control of osteoblast-specific gene expression has come from analysis of the promoter regions of genes encoding proteins like osteocalcin that are selectively expressed in bone. Both general and tissue-specific transcription factors control this promoter. Osf2/Cbfal, the first osteoblast-specific transcription factor to be identified, is expressed early in the osteoblast lineage and interacts with specific DNA sequences in the osteocalcin promoter essential for its selective expression in osteoblasts. The OSF2/CBFA1 gene is necessary for the development of mineralized tissues, and its mutation causes the human disease, cleidocranial dysplasia. Committed osteoprogenitor cells already expressing Osf2/Cbfa1 must synthesize a collagenous ECM before they will differentiate. A ceII:ECM interaction mediated by integrin-type cell-surface receptors is essential for the induction of osteocalcin and other osteoblast-related proteins. This interaction stimulates the binding of Osf2/Cbfa 1 to the osteocalcin promoter through an as-yet-undefined mechanism.
Molecular and Genetic Analyses of Actinomyces SPP
Authors: Yeung M.K.
Published: January 2009

Members of the genus Actinomyces are predominant primary colonizers of the oral cavity and play an important role in initiating plaque development. These bacteria have evolved unique mechanisms that favor colonization and persistence in this micro-environment. The expression of cell-surface fimbriae is correlated with the ability of these bacteria to adhere to specific receptors on the tooth and mucosal surfaces, and to interact with other plaque bacteria. The elaboration of sialidase is thought to enhance fimbriae-mediated adherence by unmasking the fimbrial receptors on mammalian cells. The presence of certain cell-associated or extracellular enzymes, including those involved in sucrose or urea metabolism, may provide the means for these bacteria to thrive under conditions when other growth nutrients are not available. Moreover, these enzyme activities may influence the distribution of other plaque bacteria and promote selection for Actinomyces spp. in certain ecological niches. The recent development of a genetic transfer system for Actinomyces spp. has allowed for studies the results of which demonstrate the existence of multiple genes involved in fimbriae synthesis and function, and facilitated the construction of allelic replacement mutants at each gene locus. Analyses of these mutants have revealed a direct correlation between the synthesis of assembled fimbriae and the observed adherence properties. Further genetic analysis of the various enzyme activities detected from strains of Actinomyces should allow for an assessment of the role of these components in microbial ecology, and their contribution to the overall success of Actinomyces spp. as a primary colonizer and a key player in oral health and disease.
Apoptosis and Predisposition To Oral Cancer
Authors: Polverini PJ , Nor J.E.
Published: January 2009

The term apoptosis, also known as programmed cell death (PCD), was coined by developmental biologists a number of years ago to describe a form of cell death characterized by several unique morphological and biochemical features. Genetic studies of the round worm Caeneorhabditis elegans, a simple multicellular organism, first revealed apoptosis to be an integral part of the developmental program. Subsequently, the importance of apoptosis in higher organisms was demonstrated in several eukaryotic systems. In mammals, apoptosis is widespread during embryogenesis and in adult tissues. It is required for normal tissue homeostasis and for clonal selection in the immune system. In both developing and adult organisms, apoptosis plays a central role in reinforcing appropriate cellular patterns and in regulating cell number by eliminating cells that are harmful or no longer needed. It is becoming increasingly clear that disruption in the apoptosis pathway can contribute to the development of a number of developmental, inflammatory, degenerative, and neoplastic diseases. The effector arm of the apoptotic program includes members of the Bcl-2 gene family that function as either death agonists or death antagonists. These proteins participate in an elaborate genetically controlled biochemical pathway that functions to maintain tissue and organ homeostasis and serve as a critical defense mechanism to guard against malignant transformation. Cancer is the result of a series of genetic lesions that include activation of oncogenes and inactivation or loss of tumor suppressor genes. Several groups of investigators have observed that deregulated expression of oncogenes can subvert apoptotic pathways, resulting in prolonged cell survival. In pathological settings such as cancer, members of the Bcl-2 gene family are able to synergize with oncogenes and tumor suppressor genes to transform cells. In this review, we describe the process of apoptosis in mammalian cells and define the role and biochemical pathways through which the Bcl-2 gene family induce and/or protect cells from apoptosis. Last, we will discuss the evidence which suggests that alterations in this pathway may play a central role in tumorigenesis by allowing genetically damaged cells normally destined for elimination to persist, predisposing them to additional mutations and driving them to malignancy.
Angiogenesis in the Development of Head and Neck Cancer and Its Inhibition By Chemopreventive Agents
Authors: Lingen M.W.
Published: January 2009

Squamous cell carcinoma is an aggressive malignancy that often develops as multiple independent lesions throughout the mucosa of the upper aerodigestive tract. Therefore, the comprehensive treatment of this disease must not only address the initial primary neoplasm, but also prevent the progression of the premalignant lesions lurking throughout the rest of the mucosal surfaces. The need to treat these lesions has resulted in a search for chemopreventive agents that can halt or even reverse their malignant progression. The biologic and molecular mechanisms by which most chemopreventive agents act have remained unclear and controversial. Recent work from several laboratories has demonstrated that some drugs may act in part by inhibiting the ability of tumors to induce blood vessel growth. Angiogenesis, the growth of new blood vessels from pre-existing ones, is absolutely required for solid neoplasms to grow beyond 2-3 mm in diameter. Therefore, chemopreventive agents that act to inhibit angiogenesis may provide a very powerful modality by which one may limit the growth of both premalignant lesions and small nests of tumor cells. This review will outline the basic changes that occur in tumor cells that result in the switch from an anti-angiogenic to an angiogenic phenotype. In addition, it will discuss the mechanisms by which some chemopreventive agents, presently under clinical investigation, inhibit tumor angiogenesis. Finally, this paper will present a rationale for the use of multiple anti-angiogenic agents as a means of developing new chemopreventive protocols that result in reduced patient toxicity while maintaining similar clinical efficacies.
Bone Marrow Stromal Cells: Characterization and Clinical Application
Authors: Krebsbach P.H. , Kuznetsov S.A. , Bianco P. , Gehron Robey P.
Published: January 2009

The bone marrow stroma consists of a heterogeneous population of cells that provide the structural and physiological support for hematopoietic cells. Additionally, the bone marrow stroma contains cells with a stem-cell-like character that allows them to differentiate into bone, cartilage, adipocytes, and hematopoietic supporting tissues. Several experimental approaches have been used to characterize the development and functional nature of these cells in vivo and their differentiating potential in vitro. In vivo, presumptive osteogenic precursors have been identified by morphologic and immunohistochemical methods. In culture, the stromal cells can be separated from hematopoietic cells by their differential adhesion to tissue culture plastic and their prolonged proliferative potential. In cultures generated from single-cell suspensions of marrow, bone marrow stromal cells grow in colonies, each derived from a single precursor cell termed the colony-forming unit-fibroblast. Culture methods have been developed to expand marrow stromal cells derived from human, mouse, and other species. Under appropriate conditions, these cells are capable of forming new bone after in vivo transplantation. Various methods of cultivation and transplantation conditions have been studied and found to have substantial influence on the transplantation outcome The finding that bone marrow stromal cells can be manipulated in vitro and subsequently form bone in vivo provides a powerful new model system for studying the basic biology of bone and for generating models for therapeutic strategies aimed at regenerating skeletal elements.
BMP Receptors in Limb and Tooth Formation
Authors: Cheifetz S.
Published: January 2009

Members of the TGF-β superfamily signal through receptor complexes comprised of type I and type II receptors. These receptors, which are serine/threonine kinases, form two new classes of transmembrane receptor kinases. The activity of both of the kinases is necessary for signal transduction in response to ligand binding. Bone morphogenetic proteins (BMPs), which are members of the TGF-β superfamily, bind to multiple type I and type II receptors. There is growing evidence to support the hypothesis that the BMP receptors are differentially regulated during development and that they have both unique and overlapping functions. Thus, the nature and distribution of the BMP receptors, which are reviewed here in the context of the development of limbs and teeth, appear to be critical in the control of the diverse activities of BMPs.
Chloride Channels and Salivary Gland Function
Authors: Melvin J.E.
Published: January 2009

Fluid and electrolyte transport is driven by transepithelial Cl- movement. The opening of Cl- channels in the apical membrane of salivary gland acinar cells initiates the fluid secretion process, whereas the activation of Cl- channels in both the apical and the basolateral membranes of ductal cells is thought to be necessary for NaCl re-absorption. Saliva formation can be evoked by sympathetic and parasympathetic stimulation. The composition and flow rate vary greatly, depending on the type of stimulation. As many as five classes of Cl- channels with distinct gating mechanisms have been identified in salivary cells. One of these Cl- channels is activated by intracellular Ca2+, while another is gated by cAMP. An increase in the intracellular free Ca2+ concentration is the dominant mechanism triggering fluid secretion from acinar cells, while cAMP may be required for efficient NaCl re-absorption in many ductal cells. In addition to cAMP- and Ca 2+-gated Cl- channels, agonist-induced changes in membrane potential and cell volume activate different Cl- channels that likely play a role in modulating fluid and electrolyte movement. In this review, the properties of the different types of Cl- currents expressed in salivary gland cells are described, and functions are proposed based on the unique properties of these channels.
Treatment Outcome in Cleft Lip and Palate: Issues and Perspectives
Authors: Molsted K.
Published: January 2009

In the last 40 years, great progress has been made toward a better understanding of many aspects of the cleft lip and palate defect, but there is still a long way to go before there is agreement on the optimal treatment procedures. With regard to the primary operations, it can be stated, in a somewhat simplified form, that there are two main schools of thought in cleft treatment. One advocates early closure of the lip and palate, a procedure which imparts a high priority to early speech function. The other recommends delayed closure of the hard palate, thereby according a high priority to the growth of the maxilla A number of intercenter and multicenter studies have been carried out recently in an effort to elucidate which procedures give the best result, both esthetically and functionally. The results are ambiguous, and this has led a number of researchers to suggest that the randomized clinical trial is the only way to resolve the ambiguity. The fact that it has proved difficult to identify the optimal procedures in the field of cleft lip and palate treatment need not only be due to a less than optimal research design: a contributory factor might also be the great variability in craniofacial morphology and in the response to treatment in patients who have exactly the same cleft lip and palate diagnosis. Intensive research has made it possible to state categorically that clefts occur due to many different factors in an interplay between genetics and environment. Therefore, it is not likely that a single gene can be responsible for clefting. Since scar tissue presents many problems-for instance, impairment of growth-the reduction or prevention of scar formation has long been a desirable goal. The discovery that a fetus can heal without scar formation has led to many animal experiments. The timing of the surgical intervention on fetuses is critical, since late-gestation fetuses heal with adult-like scarring. There are still many unsolved problems connected with fetal surgery, and at present prenatal surgery for repair of cleft lip and palate is not ethically defensible in humans. On the other hand, it appears that there are considerable possibilities for the reduction of human scarring after surgery with the introduction of various wound-healing medications.
The Antimicrobial Treatment of Periodontal Disease: Changing the Treatment Paradigm
Authors: Loesche W.J.
Published: January 2009

Over the last 100 years, methods of surgical periodontal treatment have enjoyed a history of success in improving oral health. The paradigm of care is based on the "non-specific plaque hypothesis"-that is, the overgrowth of bacterial plaques cause periodontal disease, and the suppression of this overgrowth reduces disease risk. The central feature of this approach to care is the removal of inflamed gingival tissue around the teeth to reduce periodontal pocket depth, thereby facilitating plaque removal by the dentist and by the patient at home. Over the last 30 years, with the recognition that periodontal disease(s) is caused by specific bacteria and that specific antimicrobial agents can reduce or eliminate the infection, a second paradigm has developed. This new paradigm, the "specific plaque hypothesis", focuses on reducing the specific bacteria that cause periodontal attachment loss. The contrast between the two paradigms can be succinctly stated as follows: The antimicrobial therapy reduces the cause, while the surgical therapy reduces the result of the periodontal infection. The specific plaque hypothesis has two important implications. First, with the increasing attention to evidence-based models for prevention, treatment, outcome assessment, and reimbursement of care, increasing attention and financial effort will be channeled into effective preventive and treatment methods. Second, the recent observations that periodontal infections increase the risk of specific systemic health problems, such as cardiovascular disease, argue for the prevention and elimination of these periodontal infections. This review highlights some of the evidence for the specific plaque hypothesis, and the questions that should be addressed if antimicrobial agents are to be used responsively and effectively.
In Vivo Gene Transfer To Salivary Glands
Authors: Baum B.J. , O'Connell B.C.
Published: January 2009

Considerable progress has occurred recently in transferring foreign genes to different tissues in vivo. Gene transfer to salivary glands has mirrored progress in the general field. Most salivary studies have utilized replication-deficient, recombinant adenoviruses as gene transfer vectors in rat models. These vectors are able to transduce almost all rat salivary epithelial cell types and lead to relatively high levels of transgene expression. Additionally, successful, though quite modest, gene transfer to salivary glands has been achieved with retroviral vectors and with different plasmid conjugates (liposomes; non-recombinant adenoviruses). Salivary gland gene transfer has been used for two potential clinical goals: (i) the repair of hypo-functional gland parenchyma, and (ii) the production of secretory transgene products for either systemic or upper gastrointestinal tract pharmaceutical use. Gene transfer can also be used as a powerful tool to alter cellular phenotype in vivo and probe cell biological questions. The current spectrum of studies demonstrates the potential broad and profound influence gene transfer can make on salivary physiology and pathophysiology.
GTP-Binding Proteins and Regulated Exocytosis
Authors: Watson E.L.
Published: January 2009

Regulated exocytosis, which occurs in response to stimuli, is a two-step process involving the docking of secretory granules (SGs) at specific sites on the plasma membrane (PM), with subsequent fusion and release of granule contents. This process plays a crucial role in a number of tissues, including exocrine glands, chromaffin cells, platelets, and mast cells. Over the years, our understanding of the proteins involved in vesicular trafficking has increased dramatically. Evidence from genetic, biochemical, immunological, and functional assays supports a role for ras-like monomeric GTP-binding proteins (smgs) as well as heterotrimeric GTP-binding protein (G-protein) subunits in various steps of the vesicular trafficking pathway, including the transport of secretory vesicles to the PM. Data suggest that the function of GTP-binding proteins is likely related to their localization to specific cellular compartments. The presence of both G-proteins and smgs on secretory vesicles/granules implicates a role for these proteins in the final stages of exocytosis. Molecular mechanisms of exocytosis have been postulated, with the identification of a number of proteins that modify, regulate, and interact with GTP-binding proteins, and with the advent of approaches that assess the functional importance of GTP-binding proteins in downstream, exocytotic events. Further, insight into vesicle targeting and fusion has come from the characterization of a SNAP receptor (SNARE) complex composed of vesicle, PM, and soluble membrane trafficking components, and identification of a functional linkage between GTP-binding and SNARES.
Interstitial Fluid Pressure in Normal and Inflamed Pulp
Authors: Heyeraas K.J. , Berggreen E.
Published: January 2009

Tissue pressure is the hydrostatic pressure in the interstitial fluid which surrounds the pulpal cells. This pressure outside the vessels is normally considerably lower than the blood pressure inside the vessels. The dental pulp has a relatively low interstitial compliance due to its enclosure between rigid dentin walls. Accordingly, even a modest increase in pulpal fluid volume will raise the tissue pressure, which may compress blood vessels, leading to ischemia and necrosis. Inflammation may lead to an increase in both interstitial fluid volume and blood volume in the low-compliant pulp and thereby increase the tissue pressure. However, the increased tissue pressure may, in turn, initiate increased lymph flow and absorption of fluid into capillaries in nearby non-inflamed tissue. Both of these latter factors will transport fluid out of the affected area and subsequently out of the tooth and consequently lower the tissue pressure. Increased tissue pressure, whether caused by increased blood volume or increased capillary filtration, will promote outward flow of fluid through exposed dentin tubules and thereby help to protect the pulp against entry of harmful substances. It seems physiologically beneficial, therefore, for the pulp to have a high tissue pressure, which promptly increases when blood flow increases due to its low compliance.
Oral Colonization By Candida Albicans
Authors: Cannon R.D. , Chaffin W.L.
Published: January 2009

C andida albicans is a commensal yeast normally present in small numbers in the oral flora of a large proportion of humans Colonization of the oral cavity by C. albicans involves the acquisition and maintenance of a stable yeast population. Micro-organisms are continually being removed from the oral cavity by host clearance mechanisms, and so, in order to survive and inhabit this eco-system, C. albicans cells have to adhere and replicate. The oral cavity presents many niches for C. albicans colonization, and the yeast is able to adhere to a plethora of ligands. These include epithelial and bacterial cell-surface molecules, extracellular matrix proteins, and dental acrylic. In addition, saliva molecules, including basic proline-rich proteins, adsorbed to many oral surfaces promote C. albicans adherence. Several adhesins present in the C. albicans cell wall have now been partially characterized. Adherence involves lectin, protein-protein, and hydrophobic interactions. As C. albicans cells evade host defenses and colonize new environments by penetrating tissues, they are exposed to new adherence receptors and respond by expressing alternative adhesins. The relatively small number of commensal C andida cells in the oral flora raises the possibility that strategies can be devised to prevent oral colonization and infection. However, the variety of oral niches and the complex adherence mechanisms of the yeast mean that such a goal will remain elusive until more is known about the contribution of each mechanism to colonization.
Craniofacial Pain and Motor Function: Pathogenesis, Clinical Correlates, and Implications
Authors: Stohler C.S.
Published: January 2009

Many structural, behavioral, and pharmacological interventions imply that favorable treatment effects in musculoskeletal pain states are mediated through the correction of muscle function. The common theme of these interventions is captured in the popular idea that structural or psychological factors cause muscle hyperactivity, muscle overwork, muscle fatigue, and ultimately pain. Although symptoms and signs of motor dysfunction can sometimes be explained by changes in structure, there is strong evidence that they can also be caused by pain. This new understanding has resulted in a better appreciation of the pathogenesis of symptoms and signs of the musculoskeletal pain conditions, including the sequence of events that leads to the development of motor dysfunction. With the improved understanding of the relationship between pain and motor function, including the inappropriateness of many clinical assumptions, a new literature emerges that opens the door to exciting therapeutic opportunities. Novel treatments are expected to have a profound impact on the care of musculoskeletal pain and its effect on motor function in the not-too-distant future.
Collaborative Treatment for the Psychosomatic Couple
Authors: Thoburn John , Hoffman-Robinson Gwynith , Shelly Lauren J. , Sayre George
Published: January 2009

This article reflects on the conceptualization and treatment strategies associated with a systems perspective of the somatic couple. It is suggested that resistance to change, nurturance of the somatic patient by his or her partner, and rigid role taking serve to promote relationship stability and individual pseudopower at the cost of patient health. The authors suggest that psychotherapists can aid primary care physicians in more effective treatment for somatizing patients by educating physicians about the role of the couple relationship in the maintenance of somatic disorder, how the somatizing patient can triangulate health care into an unstable dyadic relationship, and the usefulness of a multidisciplinary, contextual approach to the treatment of somatization. A case example is offered to demonstrate these concepts.
Select Parent and Family System Correlates of Adolescent Current Weight Status: A Pilot Study
Authors: Hooper Lisa M. , Burnham Joy J. , Richey Rachel
Published: January 2009

In this exploratory, correlational study, the researchers examined the extent to which select family systems theory constructs were associated with self-reported current weight among a sample of 77 primarily non-Hispanic Black adolescents. We also explored the extent to which select parental and familial constructs (family cohesion, family conflict, family resources, and perceptions of weight), and parents' current weight status separately and taken together predicted adolescents' current weight. Bivariate analyses suggested that adolescents' self-reported weight status is correlated with factors from multiple levels in which the adolescent is embedded; adolescent weight status was positively associated with parent- and family-level factors. Furthermore, the exploratory regression model established the existence of a small significant relationship (22% of the variance) between the parent- and family-level constructs and adolescent weight status, with parents' perception of his or her own weight status and family resources being the strongest unique predictors. These findings point to the potential importance of systemic factors related to adolescent weight status.
Fathers' Forgiveness as a Moderator Between Perceived Unfair Treatment by a Family of Origin Member and Anger With own Children
Authors: Lee Yu-Rim , Enright Robert D.
Published: January 2009

This study examined how forgiveness mediates and moderates between fathers' perceived unfair treatment (PUT) from a family of origin member and anger with the child (AWC). Eighty married fathers who have at least one child between the ages of 2 and 7 years individually completed the Opening Questionnaire, the Enright Forgiveness Inventory, the Family of Origin Hurt Scale, the Anger With the Child Scale, and the State Trait Anger Expression Inventory-II. The moderation analysis revealed that for 20 fathers who had been hurt by their own fathers and who indicated their son as between 2 and 7 years, forgiveness significantly moderated the relationship between PUT and AWC (p = .034). These results suggest an intergenerational gender effect of forgiveness between PUT and AWC.
Ecosystemic Perspective: An Interview With Peter A. D. Sherrard
Authors: Mistler Brian J. , Sherrard Peter A. D.
Published: January 2009

Dr. Peter A. D. Sherrard, associate professor of counselor education at the University of Florida is interviewed by Brian J. Mistler. The interview includes discussion of the concept of systems with an emphasis on cybernetic and ecosystemic perspectives; Dr. Sherrard's own life and experiences; the various influences on family therapy; the solution focused approach; feedback; creativity; Gestalt Therapy; metalogue; self-transcendence; pattern recognition; change; wholism; pragmatism; social construction; Zen meditation; attention; mystery; couples counseling; training groups; T-groups; behaviorism; religious conversion; theology; the Holy; serendipity; kidnapping; experts; existentialism; arbitrary punctuation; mind; culture; values; ethics; deafness; differentiation; negotiation; quantum theory; and the work of Gregory Bateson, Milton Erickson, Steve DeShazer, Carl Rogers, Paul Watzlawick, Ludwig Wittgenstein, Charles Sanders Peirce, William James, Roger Fisher, William L. Ury, Peter Berger, Dan Marino, Joe Montana, Nevitt Sandord, David Schnarch and Murray Bowen.