bluuebunny/crossref_metadata_2025 huggingface dataset:
Carboxypeptidase M as a marker of macrophage maturation
Authors: Krause Stefan W , Rehli Michael , Andreesen Reinhard
Published: April 2006

Summary: During terminal maturation of blood monocytes (MO) into macrophages (MAC), a multitude of phenotypic and functional changes occur: cells increase in size and enhance their capacity for phagocytosis and tumor cytotoxicity, but decrease their ability for T‐lymphocyte stimulation. The pattern of secreted cytokines is shifted as is the profile of surface antigens. The identity of the MAC maturation‐associated antigen MAX.1/ MAX.11 with carboxypeptidase M (CPM), a phosphoinositollinked endopeptidase, was recently described, CPM is able to process a multitude of different substrates, among them immunologically important peptides such as bradykinin, anaphylatoxins and enkephalins. It was previously shown to be expressed in placenta, lung and kidney. CPM as detected by MAX. 1/11 shows a strong expression on MO‐derived MAC in vitro and on MAC in vivo accompanying T‐lymphocyte activation such as during allogeneic transplant rejection or allergic alveolitis. In contrast, its expression is suppressed on MAC by some types of tumor cells, A synchronous expression of CPM together with MAC cytotoxic function makes a functional relationship very well possible. However, the biological importance of CPM expression on MAC in vivo is difficult to predict, since a wide range of biologically active peptides are substrates for CPM, and the relevance for most of those peptides to be processed by CPM during an immune reaction is only poorly understood at present.
The downregulation of CD4 and MHC‐I by primate lentiviruses: a paradigm for the modulation of cell surface receptors
Authors: Piguet Vincent , Schwartz Olivier , Le Gall Sylvie , Trono Didier
Published: April 2006

Summary: The human and simian immunodeficiency viruses (HIV and SIV) downregulate the cell surface expression of CD4. their primary receptor, and of class I histocompatibility complex (MHC‐I), a critical mediator of immune recognition. While the first of these effects seems important to preserve viral infectivity, the second likely promotes immune evasion. Three HIV‐1 proteins, Nef, Env and Vpu, contribute Eo downregulate CD4. Env forms a complex with CD+ in the endoplasmic reticulum, thereby retaining the receptor in this compartment. Nef and Vpu, on the other hand, act as connectors between CD4 and specific intracellular trafficking pathways, targeting the receptor for degradation in the lysosome and the proteasome, respectively. Some of the downstream partners of the viral proteins in these events have been identified, and include the adaptor complex of clathrin‐coated pits, the β subunit of COP‐I coatomer, and the ubiquitin pathway‐related h‐βTrCP protein. HIV‐induced MHC‐I downregulation, mostly the effect of Nef, also reflects a redistribution of this receptor, with its accumulation in the Golgi. The modalities of this process, however, are as yet imperfectly understood. New evidence indicates that the mechanisms employed by primate lentiviruses to downmodulate CD4 and MHC‐I are also exploited by a number of cellular regulatory processes.
Potential strategies utilised by papillomavirus to evade host immunity
Authors: Frazer Ian H. , Thomas Ranjeny , Zhou Jian , Leggatt Graham R. , Dunn Linda , McMillan Nigel , Tindle Robert W. , Filgueira Luis , Manders Peter , Barnard Paula , Sharkey Michael
Published: April 2006

Summary: The co‐evolution of papillomaviruses (PV) and their mammalian hosts has produced mechanisms by which PV might avoid specific and non‐specific host immune responses. Low level expression of PV proteins in infected basal epithelial cells, together with an absence of inflammation and of virus‐induced cell lysis, restricts the opportunity for effective PV protein presentation to immunocytes by dendritic cells. Additionally, PV early proteins, by a range of mechanisms, may restrict the efficacy of antigen presentation by these cells. Should an immune response be induced lo PV antigens, resting keratinocytes (KC) appear resistant to interferon‐γ‐enhanced mechanisms of cytotoxic T‐lymphocyte (CTL)‐mediated lysis, and expression of PV antigens by resting KC can tolerise PV‐specific CTL. Thus, KC, in the absence of inflammation, may represent an immunologically privileged site for PV infection. Together, these mechanisms play a part in allowing persistence of PV‐induced proliferative skin lesions for months to years, even in immunocompetent hosts.
Cytomegaloviral control of MHC class I function in the mouse
Authors: Hengel Hartmut , Reusch Uwe , Gutermann Anja , Ziegler Heike , Jonjic Stipan , Lucin Pero , Koszinowski Ulrich H.
Published: April 2006

Summary: Cytomegaloviruses (CMVs) represent prototypic viruses of the (i‐subgroup of herpesviruses, Murine cytomegalovirus (MCMV) infects mice as its natural host. Among viruses, CMVs have evolved the most extensive genetic repertoire to subvert MHC class I functions. To date three MCMV proteins have been identified which affect MHC I complexes. They are encoded by members of large virus‐specific gene families located at either flanking region of the 235 kb MCMV genome. The MHC I subversive genes belong to the early class of genes and code for type I transmembrane glycoproteins. The ml52‐encoded 37/40 kDa glycoprotein interacts with MHC I transiently and retains class I complexes in the endoplasmic reticulum (ER) Golgi intermediate compartment on its journey to the endolysosome. In contrast, the m06‐encoded glycoprotein of 48 kDa complexes tightly with ternary MHC class I molecules in the ER, Due to sorting signals in its cytoplasmic tail, gp48 redirects MHC I to endolysosomal compartments for proteolytic destruction. Likewise, the 34 kDa glycoprotein encoded by mO4 binds tightly to MHC class I complexes in (he ER but the gp34/MHC I complex reaches the plasma membrane. The CD8+ T‐cell‐dependent attenuation of a m152 deletion mutant virus proves for the first time that inhibition of antigen presentation is indeed essential for the biological fitness of CMVs in vivo.
Walking through the forest of transgenic models of human disease
Authors: Eynon Elizabeth E. , Flavell Richard A. , Frost Robert
Published: April 2006

Summary: In the investigation of human disease, molecular biology has provided Immunologists with several enormously powerful tools. Trans‐genic and knockout mice provide animal models to investigate mechanisms, as well as aid in the design of therapies for these diseases. These mice have been useful in several different ways. First, as direct models of disease they provide direct tools for the study of the disease. Second, expression of individual molecules can be altered in the context of established disease models. We describe here some of the models in use as well as the limitations and promise of this research.
Transgenes and knockout mutations in animal models of type 1 diabetes and multiple sclerosis
Authors: Wong F. Susan , Dittel Bonnie N. , Janeway Charles A.
Published: April 2006

Summary: In this article, we will examine the roles of transgenic and knockout animals that aid us in understanding two autoimmune diseases ‐ type 1 (insulin‐dependent) diabetes and multiple sclerosis. The first sections will focus on studies in type 1 diabetes to show how genetically altered animals have given insight into the role of various immune cell types, autoantigens, co‐stimulatory molecules, cytokines and, finally, the role of various effector pathways in the pathogenesis of diabetes. The second section concentrating on the animal model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). will show how animals that express a T‐cell receptor derived from a clone able to cause disease have given insight into the pathogenesis of EAE.
Viruses, host responses, and autoimmunity
Authors: Horwitz Marc S. , Sarvetnick Nora
Published: April 2006

Summary: Conceptually, the initiation of autoimmune disease can be described as a three‐stage process involving both genetic and environmental influences. This process begins with the development of an autoimmune cellular repertoire, followed by activation of these autoreactive cells in response to a localized target and, finally, the immune system's failure to regulate these self reactive constituents. Viruses have long been associated with inciting autoimmune disorders. Two mechanisms have been proposed to explain how a viral infection can overcome immunological tolerance to self components and initiate an organ specific autoreactive process, these mechanisms arc molecular mimicry and bystander activation. Both pathways, as discussed here, could play pivotal roles in the development of autoimmunity without necessarily excluding each other. Transgene technology has allowed us and others to examine more closely the roles of these mechanisms in mice and to dissect the requirements for initiating disease. These results demonstrate that bystander activation is the must likely explanation fur disease development. Additional evidence suggests a further role for viruses in the reactivation and chronicity of autoimmune diseases. In this scenario, a second invasion by a previously infecting virus may restimulate already existing autoreactive lymphocytes and thereby contribute to the diversity of the immune response.
Peripheral T‐cell tolerance: the contribution of permissive T‐cell migration into parenchymal tissues of the neonate
Authors: Alferink Judith , Aigner Silke , Reibke Roland , Hämmerling Günter J. , Arnold Bernd
Published: April 2006

Summary: T lymphocytes with self‐destructive capacity are often found in healthy individuals, indicating efficient control mechanisms chat prevent chronic autoimmune deseases. Since naive T lymphocytes do not circulate through extralymphoid tissues the concept has emerged that peripheral T cells ignore tissue‐,specific antigens unless they are presented by professional antigen‐presenting cells in the lymphoid compartments. However, this view pays attention only to experiments performed in adult animals. This report reviews the evidence that tissues of neonatal mice, in contrast to adults, exhibit high accessibility for naive T cells, thereby allowing the direct contact with tissue‐specific self‐antigens on parenchymal cells during neonatal life and tolerance induction to such self‐antigens. In mouse bone marrow chimeras generated at different ages, recent thymic emigrants were tolerized to a major histocompatibility class I antigen expressed on keratinocytes only during a neonatal period and not during adulthood. Blockade of T‐cell migration neonatally prevented tolerance induction. The neonatally induced tolerance is maintained during adulthood, apparantly by a dominant regulatory mechanism. Thus, parenchymal cells and T‐cell migration in the neonate contribute to the control of autoreactive T cells.
The B‐cell system of human mucosae and exocrine glands
Authors: Brandtzaeg Per , Farstad Inger Nina , Johansen Finn‐Eirik , Morton H. Craig , Norderhaug Inger Natvig , Yamanaka Takeshi , Brandtzaeg Per , Farstad Inger Nina , Johansen Finn‐Eirik , Morton H. Craig , Norderhaug Inger Natvig , Yamanaka Takeshi
Published: April 2006

Summary: The mucosae and exocrine glands harbour the largest activated B‐cell system of the body, amounting to some 80–90% of all immunoglobulins (Ig)‐producing cells. The major product of these immunocytes is polymeric (p)IgA (mainly dimers) with associated J chain. Both pIgA and pentameric IgM contain a binding site for the polymeric Ig receptor (pIgR), or secretory component (SC), which is a requirement for their active external transport through secretory epithelia. The pIgR/SC binding site depends on covalent incorporation of the J chain into the quaternary structure of the polymers when they are produced by the local immunocytes. This important differentiation characteristic appears to be sufficient functional justification for the J chain to be expressed also by most B cells terminating at secretory effector sites with IgD or IgG production; they probably represent a ‘spin‐off’ from sequential downstream CH switching on its way to pIgA expression, thus apparently reflecting a maturational stage of effector B‐cell clones compatible with homing to these sites. Observations in IgA‐deficient individuals suggest that the magnitude of this homing is fairly well maintained even when the differentiation pathway to IgA is blocked. Certain microenvironmental elements such as specific cytokines and dendritic cells appear to be required for induction of IgA synthesis, but it remains virtually unknown why this isotype normally is such a dominating product of local immunocytes and why they have such a high level of J chain expression. Also, despite the recent identification of some important requirements in terms of adhesion molecules (e.g. integrin α4β7 and MAdCAM‐1) that explain the “gut‐seeking” properties of enterically induced B cells, the origin of regionalized homing of B cells to secretory effector sites outside the gut remains elusive. Moreover, little is known about immune regulation underlying the striking disparity of both the class (IgD, IgM) and subclass (IgA1, IgA2, IgGI, IgG2) production patterns shown by local iinmttnocytes in various regions of the body, although the topical microbiota and other environmental stimuli might be important. Rational design of local vaccines will depend on better knowledge of both inductive and migratory properties of human mucosal B cells.
Vaccine for contraception targeting sperm
Authors: Naz Rajesh K.
Published: April 2006

Summary: Development of a vaccine(s) based on sperm antigens represents a promising approach to contraception. The utility of a sperm antigen ill immunocontraception is contingent upon its tissue specificity, involvement in fertility and on raising high antibody deer, especially locally in the genital tract, that is capable of inducing reversible infertility. Several sperm antigens, such as lactate dehydrogenase C4, PH‐20, sperm protein (SP)‐10, fertilization antigen (FA)‐1, FA‐ 2, cleavage signal (CS)‐1, NZ‐1, and NZ‐2 have been proposed as potential candidates for the vaccine development. Spermzona pellucida (ZP) binding is a pivotal tissue‐ and mostly species‐specific event in the fertilization process, and the molecules involved in this site constitute che most exciting candidates for immuno‐contraception. FA‐1 is a sperm‐specific glycoprotein having receptor activity for ZR recognition and binding. Complementary DNA encoding for FA‐1 antigen has been cloned and sequenced. Active immunization of animals with recombinant FA‐1 antigen causes a long‐lasting reversible inhibition in fertility by raising a sperm‐specific immune response. This antigen is also involved in human immunoinfertility. The exciting findings from the recent trial in immunoinfertile couples indicate that the FA‐1 antigen may have clinical application in the treatment of male infertility. A vaccine having most appropriate tissue‐specific and effective recombinant and/or synthetic epitopes of various sperm antigens, such as the FA‐1 antigen, in a single formulation may provide a highly immunogenic and efficacious antisperm vaccine for contraception. The advances made during che last 5 years suggest that it may be a realistic proposition.
The specificity of proteasomes: impact on MHC class I processing and presentation of antigens
Authors: Niedermann Gabriele , Geier Eike , Lucchiari‐Hartz Maria , Hitziger Niclas , Ramsperger Arne , Eichmann Klaus
Published: April 2006

Summary: We have studied polypeptide processing by purified proteasomes, with regard to proteolytic specificity and cytotoxic T‐lymphocyte (CTL) epitope generation. Owing to defined preferences with respect to cleavage sites and fragment length, proteasomes degrade polypeptide substrates into cohorts of overlapping oligopeptides. Many of the proteolytic fragmetits exhibit structural features in common with major histocompatibility complex (MHC) class I ligands including fragment size and frequencies of amitio acids at fragment boundaries. Proteasomes frequently generate definitive MHC class I ligands and/or slightly longer peptides, while substantially larger peptides are rare. Individual CTL epitopes are produced in widely varying amounts, often consistent with immunohier‐archies among CTL epitopes. We further found that polypeptide processing is remarkably conserved among proteasomes of enkaryotic origin and that invertebrate proteasomes can efficiently produce known high‐copy MHC class I ligands, suggesting evolutionary adaptation of the transporter associated with antigen processing and MHC class I to ancient constraints imposed by proteasomal protein’ degradation.
Proteolysis and class I major histocompatibility complex antigen presentation
Authors: York Ian A. , Goldberg Alfred L , Mo X. Y. , Rock Kenneth L
Published: April 2006

Summary: The class I major histocompatibility complex (MHC class 1) presents 8–10 residue peptides to cytotoxic T lymphocytes. Most of these antigenic peptides are generated during protein degradation in the cytoplasm and are then transported into the endoplasmic reticulum by the transporter associated with antigen processing (TAP), Several lines of evidence have indicated that the proteasome is the major proteolytic activity responsible for generation of antigenic peptides—probably most conclusive has been the finding that specific inhibitors of die proteasome block antigen presentation. However, other proteases (e.g. the signal peptidase) may also generate some epitopes, particularly those on certain MHC class I alleles. The proteasome is responsible for generating the precise C termini of many presented peptides, and appears to be the only activity in ceils that can make this cleavage. In contrast, aminopeptidases in the cytoplasm and endoplasmic reticulum can trim the N terminus of extended peptides to their proper size. Interestingly, the cellular content of proteases involved in the production and destruction of antigenic peptides is modified by inter‐feron‐γ (IFN‐γ) treatment of cells, IFN‐γ indicates the expression of three new proteasome β submits that are preferentially incorporated into new proteasomes and alter their pattern of peptidase activities. These changes are likely to enhance the yield of peptides with C termini appropriate for MHC binding and have been shown to enhance the presentation of at least some antigens. IFN‐γ also upregulates leucine aminopeptidase, which should promote the removal of N‐terminal flanking residues of antigenic peptides. Also, this cytokine downregulates the expression of a metallo‐proteinase, thimet oligopeptidase that actively destroys many antigenic peptides. Thus, IFN‐γ appears to increase the supply of peptides by stimulating their generation and decreasing their destruction. The specificity and content of these various proteases should determine the amount of peptides available for antigen presentation. Also, the efficiency with which a peptide is presented is determined by the protein's half life (e.g. its ubiquitination rate) and the sequences flanking antigenic peptides, which influence the rates of proteolytic cleavage and destruction.
The role of H2‐O and HLA‐DO in major histocompatibility complex class Il‐restricted antigen processing and presentation
Authors: Alfonso Christopher , Liljedahl Monika , Winqvist Ola , Surh Charles D. , Peterson Per A. , Fung‐Leung Wai‐Ping , Karlsson Lars
Published: April 2006

Summary: The function of major histocompatibility complex (MHC) class II molecules is to sample exogenous antigens for presentation to CD4+ T helper cells. After synthesis in the endoplasmic reticulum, class II molecules are directed into the endosomal system by association with the invariant chain (Ii), which is sequentially cleaved, generating class II dimers loaded with Ii‐derived peptides (CLIP). These class Il‐peptide complexes are physiological substrates for H2‐M/HLA‐DM, a resident of the endosomal/lysosomal system which facilitates the removal of CLIP from newly synthesised class II αβ dimers. Exchange of CLIP for antigenic class Il‐binding peptides is also promoted by the action of H2‐M/HLA‐DM, resulting in stable peptide‐class II complexes that are transported to the cell surface for presentation to CD4+ T cells. Recent evidence suggests that this H2‐M/HLA‐DM‐mediated ‘peptide editing’ is influenced by another MHC class Il‐encoded molecule, H2‐O/HLA‐DO. This non‐polymorphic αβ heterodimer is associated with H2‐M/HLA‐DM during intra‐cellular transport and within the endosomal system of B cells, H2‐0/HLA‐DO alters the peptide exchange function of H2‐M/HLA‐DM in a pH‐dependent manner, so that H2‐M/HLA‐DM activity is limited to more acidic conditions, corresponding to lysosomal compartments. Indeed, H2‐O/HLA‐DO may serve to limit the presentation of antigens after fluid phase uptake by B cells, while augmenting presentation of antigens internalised via membrane Ig receptors. Such a mechanism may maintain the fidelity of the B‐cell‐CD4+ T‐cell interaction, counteracting self reactivity arising from less stringent lymphocyte activation. Here, data evaluating the role of H2‐O/HLA‐DO shall be reviewed and its putative function discussed.
The molecular basis of CD 1 ‐mediated presentation of Iipid antigens
Authors: Moody D. Branch , Besra Gurtyal S. , Wilson Ian A. , Porceili Steven A.
Published: April 2006

Summary: The CD1 family of proteins mediates a newly described pathway for presentation of lipids and glycolipids for specific recognition by T cells. All four of the known human CD1 proteins (CD1a, CD1b, CD1c and CD1d) as well as murine CD Id have now been shown to mediate T‐cell recognition of lipid or glycolipid antigens. These antigens include naturally occuring foreign glycolipids from intracellular pathogens or synthetic glycolipids that are related in structure to mammalian glycolipids. The CD l b and CD I d‐presented antigens differ in their fine structures but reveal a general motif in which a rigid hydrophilic cap is botind to two aliphatic hydrocarbon chains. Different T‐cell populations recognize individual antigens without cross‐reactivity to closely related antigen structures or CD 1 isoforms, documenting the complexity and fine specificity of CD l‐mediated T‐cell responses. Mapping of the molecular detertninants of recognition for CD 1 b and CD 1d‐preseced antigens reveals that T cells discriminate the fine structure of the hydrophilic cap of the antigen, but both the length and structure of the lipid chains may be altered without loss of recognition. This pattern of lipid antigen recognition may be accounted for by a simple molecular mechanism of presentation that parallels the known mechanism for presentation of peptides, but solves the special problems related to the hydrophobic chemical nature of the lipid antigens. We propose that CD 1 binds antigen by accommodating the two lipid tails within the hydrophobic groove of its two membrane distal domains, positioning the rigid hydrophilic cap of the antigen on the solvent‐exposed surface of the CD1 protein, where it can directly contact the T‐cell antigen receptor. This model provides a molecular basis for recognition of a new and diverse set of T‐cell antigens contained within the lipid bilayers of cellular membranes.
Dendritic cells, B cells and the regulation of antibody synthesis
Authors: MacPherson Gordon , Kushnir Natasha , Wykes Michelle
Published: April 2006

Summary: Dendritic cells (DC) are usually thought of as antigen‐presenting cells for T cells. However, recent studies from our laboratory and those of others have shown that they have important roles in B‐cell activation and regulation of antibody synthesis. Rat DC make short term interactions with resting B cells and these interactions can be stimulated by cross‐linking molecules on either cell surface. These DC can retain antigen in native form for at least 36 h in vivo and in vitro and can subsequently release it for recognition by B cells. In vivo antibody responses induced by antigen‐pulsed DC are skewed towards IgG. In vitro, naive B cells incubated with antigen‐pulsed DC subsequently secrete IgM and IgG when cultured with an antigen‐specific CD4+ T‐cell line, whereas if B cells are incubated with antigen without DC, only IgM is produced. These observations show that DC play an important role in the initiation of and regulation of antibody synthesis.
The mouse major histocompatibility complex: some assembly required
Authors: Amadou Claire , Kumánovics Attila , Jones Elsy P. , Lambracht‐Washington Doris , Yoshino Masayasu , Lindahl Kirsten Fischer
Published: April 2006

Summary: We have assembled a contig of 81 yeast artificial chromosome clones that spans 8 Mb and contains the entire major histocompatibility complex (Mhc) from mouse strain C57BL/6 (H2b), and we are in the process of assembling an Mhc contig of bacterial artificial chromosome (BAC) clones from strain 129 (H2bc), which differs from C57BL/6 in the H2‐Q and H2‐T regions. The current BAC contig extends from Tapasin to D17Leh89 with gaps in the class II, H2‐Q. and distal H2‐M regions. Only four BAC clones were required to link the class I genes of the H2‐Q and H2‐T regions, and no new class I gene was found in the previous gap. The proximal 1 Mb of the H2‐M region has been analyzed in detail and is ready for sequencing; it includes 21 class I genes or fragments, at least 14 olfactory receptor‐like genes, and a number of non‐class I genes that clearly establish a conserved synteny with the class I regions of the human and rat Mhc.
Effect of aging on the marmoset periodontium
Authors: Levy Barnet M. , Dreizen Samuel , Bernick Sol
Published: April 2006

The periodontium of old marmosets is characterized by a narrow, serrated cribriform plate of alveolar bone, a loss of tinctorial identification of Sharpey's fibers and a decrease in the cellular elements of the periodontal ligament. The attachment fibers are frequently calcified. In contrast to the blue periodontal ligament and pink alveolar bone in alcian blue‐PAS stained sections of adult marmosets, the periodontal ligament stains pink and the alveolar hone deep red in old animals. Aged marmosets also have degenerative changes in the periodontal vasculature not seen in younger adults. The changes are similar to those described in aged human periodontal tissues.
Polymorphonuclear leukocyte collagenase: Localization in granules subjected to zonal centrifugation
Authors: Robertson P. B. , Ryel R. B. , Fullmer H. M. , Taylor R. E. , Shyu K. W.
Published: April 2006

Abstract. Polymorphonuclear leukocytes were obtained from rabbit peritoneal exudates. Granule preparations from these cells were subjected to zonal fractionation through a discontinuous sucrose gradient. Azurophilic and specific granules were enzymatically characterized by peroxidase and alkaline phosphatase, respectively. Collagenase was consistently associated with the alkaline phosphatase‐containing specific granules.
The effect of collagenase‐inhibitor complexes on collagenolytic activity of normal and inflamed gingival tissue
Authors: Robertson P. H. , Grupe H. E. , Taylor R. E. , Shyu K. W. , Fullmer H. M.
Published: April 2006

Abstract. The effect of serum inhibitors on determinations of collagenolytic activity in culture fluids of healthy (G.I.=0) and mildly inflamed (G.I.=1) gingival tissue was studied. Gingival biopsies obtained at the beginning of the experimental gingivitis period (G.I.=0) and after approximately three weeks of no oral hygiene (G.I.=1) were subjected to tissue culture procedures previously utilized for the determination of collagenolytic activity. Inhibition of collagenase activity was evaluated by denaturing scrum inhibitors retained in culture fluid with sodium thiocyanate or by adding culture fluid from normal and inflamed tissues to a partially purified collagenase preparation.

A decrease in collagenolytic activity was consistently demonstrable in untreated culture fluids of gingival tissue manifesting G.I.=1 as compared lo those exhibiting G.I.=0. When enzyme containing culture fluids were treated with NaSCN. however, no essential difference was detected. While culture fluids from healthy gingiva showed no inhibition of partially purified collagenase, culture fluids from tissues manifesting mild inflammation inhibited enzyme activity by approximately 60 %.

A number of cell types associated with the periodontium have the ability to produce a specific collagenase. The results of this investigation suggest, however, that in vitro determinations of collagenolytic activity in culture fluids of normal and inflamed tissues may be influenced by specific scrum inhibitors.
Electron optic analysis of human dentin in hypophosphatemic vitamin D‐resistant rickets (Report of a kindred with consanguinity)
Authors: Sauk John J. , Witkop Carl J.
Published: April 2006

Abstract. Clinical observation of a family with consanguinity and vitamin D‐resistant rickets is presented. Patients were studied by means of clinical observation and electron optic analysis, specifically that of scanning electron microscopy. The genetics of the condition is discussed with special reference to the effect of consanguinity on the kindred. Differential diagnosis with other hypophosphatemic conditions and inborn errors of calcium metabolism are also noted.
Microradiographic study of human temporomandibular disks obtained at autopsy
Authors: Carlsson Gunnar E. , Hassleu Ove , ÖBerg Torsten
Published: April 2006

Abstract. Ninety‐six temporomandibular joint disks obtained at autopsy from subjects aged 1 day to 93 years of age and divided into three groups according to dental status were examined micro‐radiographically for calcification.

The central part of the disks showed no calcifications in individuals less than 30 years old, and only a few in persons above 30 years with a good denial status, while the occurrence was much greater in patients who had lost many or all of their teeth. In the peripheral part of the disk there were occasional calcifications already in children, and in elderly individuals the calcifications were more common, but the frequency did not appear to vary with the number of residual natural teeth or with the degree of arthrosis of the temporomandibular joint.
The microscopy of parotid atrophy after ligation of Stensen's duct
Authors: Leake Donald L. , Haydon Glen B. , Laub Donald
Published: April 2006

Abstract. Stensen's duct was ligated in 18 mature Sprague‐Dawley rats and the parotid gland was examined at intervals of up to 90 days. Standard preparatory techniques were used for light and electron microscopy. Parotid tissue decreases with time following ligation of the duct. The course from 1 week onward is one of progressive atrophy; at 3 months the number of identifiable acini is greatly decreased. The controls remained unchanged throughout the course of the study. Ligation of the parotid duct will produce glandular atrophy. The clinical implications are that for some parotid conditions ligation may be an effective treatment which avoids the hazards of parotid surgery.
Proteins of the periodontium. Biochemical studies on the collagen and noncollagenous proteins of human gingivae
Authors: Ballard John B. , Butler William T.
Published: April 2006

Abstract. Insoluble collagen was prepared from gingivae of full term, stillborn infants (SI) and from that of patients exhibiting gingival hyperplasia that was secondary to diphenylhydantoin therapy (DPH). During the preparations only 4 % of the collagen from DPH was extracted and 17 % from SI gingivae was solubilized, by neutral salt and dilute acid extractants. Subsequent amino acid analysis indicated the presence of a relatively large quantity of the noncollagenous protein(s) in the DPH collagen preparation. After collagen samples were converted to soluble cyanogen bromide (CNBr) pep‐tides, the noncollagenous protein(s) proved to be insoluble in the dilute citrate buffer routinely used for initial chromotographic separation of the CNBr peptides. This fraction, whether from DPH or SI gingivae, had essentially the same composition. The noncollagenous protein fraction comprised about 7 and 20 %, respectively, of the dry weights of the SI and DPH insoluble collagen preparations.

CNBr peptides from gingival collagen have been purified and shown to be identical with those reported for human skin collagen. Thus, the collagen of gingivae is principally of the type with the chain structure [αl(I)]2α2. Preliminary data strongly suggest the presence in gingivae of a lower level of collagen of the [al (III)]s type.
An intraoral model used for studies of fluoride incorporation in enamel
Authors: Koulourides T. , Phantumvanit P. , Munksgaard E. C. , Housch T.
Published: April 2006

Abstract. The effect of fluoride on experimental cariogenicity in man was investigated by using bovine enamel surfaces mounted in oral prosthetic appliances. Samples of sound and presoftened enamel were exposed to simulated cariogenic or noncariogenic conditions for 1 week. The samples were periodically immersed in vitro in solutions containing 1 ppm fluoride. For the cariogenic condition, the immersion solution was 3% sucrose, for the noncariogenic condition, water. After the experimental period, the sample enamel was assessed for hardness change and fluoride incorporation. Under the non‐cariogenic condition, partial remineralization and high fluoride incorporation were found in the presoftened enamel; both hardness change and fluoride incorporation in sound enamel were minor. The cariogenic condition contributed to higher enamel softening and higher fluoride uptake by both types of samples. The findings suggest a mechanism through which intermittent cariogenesis and remineralization in the presence of fluoride may contribute to increased tooth resistance to caries.
A histological study of tooth allografts transplanted to untreated and immunologically prepared mice
Authors: Atkinson M. E.
Published: April 2006

Ten‐day‐old mouse teeth were grafted subcutaneously into adults of an unrelated strain which were either untreated or had rejected a skin graft from the same strain as the tooth donors. First set allografts degenerated rapidly after grafting and were only sparsely repopulated subsequently. No cell‐mediated Immune response was observed. In contrast, second set allografts were heavily infiltrated with mononuclear leukocytes which persisted throughout the study, although the coronal pulp was never involved. It was suggested that first set allografts did not suffer a cell‐mediated response because rapid degeneration of the cellular components removed the immunogenic target tissue before the host response could be effected.
Histopathologic Evaluation of three Ultraviolet‐Activated Composite Resins on Monkey pulps
Authors: Heys R. J. , Heys D. R. , Cox C. F. , Avery J. K.
Published: April 2006

The pulpal responses of three ultraviolet‐activated composite resins, Nuva‐Fil®, Experimental UV #1® and Experimental UV #2®, were tested on adult monkey teeth using silicate and zinc oxide eugenol (ZOE) as positive and negative controls. All materials were placed in Class V cavity preparations in Rhesus monkey teeth using approximately 48 anterior and 63 posterior teeth of both the maxillary and mandibular arches. A total of 111 teeth were utilized and all materials were evaluated at 3 days, 5 and 8 weeks. Following left ventricular perfusion, the teeth were prepared for microscopic evaluation using routine histological procedures. The 3‐day pulpal response of all the ultraviolet‐activated composites was slight with some disruption and vacuolization in the odontoblastic layer and a slight inflammatory response. At 5 weeks there was a reduction of the inflammatory response and the formation of reparative dentin was noted for all ultraviolet composites. The 8‐week pulp response was slight, characterized by a minimal inflammatory response adjacent to the zone of reparative dentin. Generally, ZOE produced the mildest response while silicate produced the most severe response at the three time intervals.
Effects of Bicarbonate on Remineralization of Enamel
Authors: Feagin F. F. , Thiradilok S. , Aponte‐Merced L. , Bradley E.
Published: April 2006

Enamel surfaces were demineralized in acetic acid and remineralized in solutions that contained 1.5 nM calcium, 1.0 nM phosphate, and 0.0, 5, 15, and 25 mM NaHCO3, and 0.00 or 5.0 mM NaF at pH 7.0. NaF in CO2‐free solutions increased the rates of calcium and phosphate uptake during remineralization. Bicarbonate in NaF‐free solutions caused small increases of calcium and phosphate uptake. Bicarbonate with NaF in solutions synergistically increased calcium uptake, but did not affect phosphate uptake. Bicarbonate reduced fluoride uptake by about 50 % during remineralization, and increased the Ca/P ratios of deposited minerals from about 1 (dicalcium phosphate) to approach and exceed the ratios of apatites.
Odontogenic Myxoma — Clinical Concept and Morphological Studies*
Authors: Gundlach Karsten K. H. , Schulz Andreas
Published: April 2006

Our experience with the odontogenic myxoma of the mandible is presented. Although it is a benign, slow growing neoplasm, it is locally aggressive. Patients rarely complain of any symptoms produced by this tumor. Morphological studies included enzyme histochemistry, as well as light and electron microscopy. Two major types of tumor cells were identified. One resembled a mature fibroblast, while the other had the morphological and functional criteria of a so‐called myxoblast. We would recommend therapy comprising wide resection and consecutive primary osteoplasty.
Odontoblast metabolism in rats deficient in vitamin D and calcium I
Authors: Engström C. , Linde A. , Magnusson B. C.
Published: April 2006

Different rat diets, deficient in calcium and/or vitamin D, were tested for varying experimental periods to obtain changes in serum calcium values, body weight gain and odontoblast‐predentine morphology. One diet, R 25, used during a 14‐day period, was found to induce lowered serum calcium values and an increased predentin width in incisor teeth. Rats fed this diet demonstrated an increase in alkaline phosphatase and ATP‐splitting enzyme activity in dentinogenically active incisor odontoblasts. No other metabolic changes in these cells were demonstrated by the histochemical methods employed.
Granular Cell Ameloblastoma: Electron Microscopic Observations
Authors: Tandler Bernard , Rossi Edward P.
Published: April 2006

A case of granular cell ameloblastoma was studied by light and electron microscopy. Histologically, the lesion resembled simple ameloblastoma, but differed from the latter in that it contained many cells with granular eosinophilic cytoplasm. Ultrastructurally, the cytoplasmic granules were identified as lysosomes. These organelles were particularly abundant in cells situated in the center of islands and clusters of neoplastic cells. Since no cytoplasmic components could be identified in any of these lysosomes, it was concluded that they are not engaged in autophagy or in remodeling of the neoplastic cells.
Can therapeutic considerations provide clues to the etiology of aphthous stomatitis and Behçet's syndrome?
Authors: Rytel Michael W.
Published: April 2006

Abstract An attempt is made to derive clues as to the etiology of aphthous stomatitis and Behçet's syndrome from analysis of the mode of action of the various therapeutic agents which have been employed in these diseases. It is concluded that owing to the diverse and frequently contrasting modes of action of these agents, this may well be an unproductive task. There is one exception to this conclusion. Since levamisole in small concentrations given intermittently appears to act as an immunopotentiator, and in large, prolonged dosages possibly as an immunosuppressora, future “diagnostic‐therapeutic” trials could examine this dichotomy to determine whether aphthous stomatitis and Behçet's syndrome are infectious or hypersensitivity diseases.
Effect of levamisole on the incidence and prevalence of recurrent aphthous stomatitis
Authors: Miller Michael F. , Silvert Michael E. , Laster Larry L. , Green Paul , Ship Irwin I.
Published: April 2006

Abstract Twenty patients with severe recurrent aphthous stomatitis were treated with a new drug, levamisole, to determine its effects upon the incidence and prevalence of recurrent aphthous stomatitis. The trial, conducted in a non‐crossover, double‐blind fashion, did not demonstrate any statistically significant differences when levamisole and placebo groups were compared over time either in the number of ulcers, number of ulcer‐days, mean duration of ulcers, or mean number of ulcers per day. Positive subjective results were experienced by the 10 patients receiving levamisole but these were not of sufficient magnitude to affect group mean differences.
Ocular manifestations of Behçet's disease
Authors: Benezra David , Nussenblatt Robert
Published: April 2006

Abstract The manifestations, possible etiological factors and therapeutical modalities of ocular Behçet are outlined. The major ocular findings involve both the anterior and posterior uvea. The vasculitis retinae, the periphlebitis and the pipe stem sheathing along with the recurrent vitreous hemorrhages lead to the visual impairment. Exacerbation and remission of the ocular inflammatory processes are characteristic. However, the impairment of visual function occurring after each attack is generally irreversible. The effectiveness of the present modalities of treatment is uncertain. Chlorambucil ® in doses of 6–8 mg daily appears to have an outstanding beneficial effect. However, carefully monitored control studies are lacking and should be conducted before any unequivocal conclusions can be reached.

It appears to us that the etiology‐pathology of Behçet's disease might be a sequence of events triggered by an interaction between a virus and specific receptors on the host cell membrane (HLA determined?). This initial interaction is followed by a malregulation of the host immune mechanism leading to autoimmune phenomena which are characteristics of the disease.
Oral lesions in renal transplant patients
Authors: Tyldesley W. R. , Rotter Emma , Sells R. A.
Published: April 2006

Abstract Plaque‐like lesions of the oral mucosa have been observed in seven immunosuppressed renal transplant patients. Whilst bearing a superficial resemblance to acute pseudomembranous candidiasis (thrush), these lesions have been shown to be associated with bacterial overgrowth and not with fungi. Treatment has depended on the use of appropriate antibiotics and antiseptics together with the adoption of measures to cause disintegration of the mucoid matrix of the lesions.
Intracellular collagen in recurrent ameloblastic fibroma
Authors: Gotjamanos T.
Published: April 2006

Abstract. Electron microscopic examination of tissue from a twice recurrent ameloblastic fibroma revealed the presence of intracellular collagen fibres in fibroblasts active in protein synthesis. The intracellular fibres were morphologically identical to collagen fibres located extracellularly. The literature on intracellular collagen in biological systems and pathological states has been reviewed, and attention is focussed on collagen phagocytosis and degradation by fibroblasts which are currently considered to represent the basis of connective tissue remodelling and turnover.
The crystal chemistry of submandibular and parotid salivary gland stones
Authors: Burstein Leslie S. , Boskey Adele L. , Tannenbaum Paul J. , Posner Aaron S. , Mandel Irwin D.
Published: April 2006

Abstract. The mineral composition of 38 human salivary gland stones was described qualitatively on the basis of X‐ray diffraction and chemical analyses. In 32 submandibular stones, hydroxyapatite was the most frequently observed phase with a magnesium‐substituted whitlockite co‐phase (octacalcium phosphate was rarely present). In six parotid gland stones, apatite, magnesium substituted whitlockite and octacalcium phosphate were noted to be the major crystalline phases. Brushite was rarely found in either submandibular or parotid stones. This is the first report of octacalcium phosphate in salivary gland stones. All stones had ash weights ranging from 75–80%, but their Ca/P ratios could not be used to predict the crystalline phases present. Whitlockite was observed more frequently in the central regions of the submandibular stones than in the outer crusts. Possible explanations for the presence of each of these phases are discussed.
Tumorous conditions of the fibula, supraorbital area and mandible
Authors: Weir J. C. , Amonett M. R. , Krolls S. O.
Published: April 2006

Abstract. Our patient's initial biopsy of the right fibula was diagnosed as Ewing's sarcoma and surgical amputation was suggested as the treatment of choice. After he refused, he was treated with chemotherapy and radiotherapy. The patient refused to continue this type of therapy after a 6 weeks' regimen.

The supraorbital swelling occurred 3 years later and the biopsy of it also revealed Ewing's sarcoma, as did the mandibular specimen.

The patient, again, refused any further treatment.
Effect of fluoride on ion exchange, remineralization and acid resistance of surface enamel
Authors: Aponte‐Merced L. A. , Feagin F. F.
Published: April 2006

Abstract. In a system of constant ion activities the rates of F− exchange in enamel, under conditions of exchange alone and remineralization, depended on the concentration of F− in solutions. Acid resistance of surface minerals resulted from exchange of F− for OH− in the enamel at pH 7.0 and 4.5 The leve lof 0.5 mM NaF, compared to 0.05 and 5.0 mM, caused maximum rates of isotopic exchange of 45Ca and maximum acid resistance of enamel. Similarly low levels of F− may be feasible for use in caries prevention in the absence and presence of remineralization.
Scanning electron microscopic study of oral leukoplakia*
Authors: Bánóczy Jolán , Lapis Karoly , Albrecht Maria
Published: April 2006

Abstract Biopsy specimens of buccal mucosa from six oral leukoplakia patients and one specimen of normal buccal mucosa were studied by scanning electron microscopy. The results showed: (1) There was a difference between the surfaces of normal and leukoplakia epithelial cells. (2) The appearance varied with the clinical type of leukoplakia: in leukoplakia verrucosa, epithelial cells appeared keratinized; in leukoplakia erosiva, epithelial cells were dissociated. (3) Histologically, dysplastic erosive leukoplakia was characterized by an atypical arrangement of superficial cytoplasmic projections of epithelial cells.
Oral condyloma acuminatum A Case Report with Light Microscopic and Ultrastructural Features
Authors: Shaffer Edward L. , Reimann Bernhard E. F. , Gysland Wayne B.
Published: April 2006

Abstract A case of intraoral condyloma acuminatum with clinical, light microscopic, and ultrastructural features is presented. The presence of intranuclear virus particles is demonstrated by electron microscopy. To the best of our knowledge, the presence of viruses has not previously been reported in the oral lessions of this disease.
Electron dense staining affinities of mouse oxytalan and elastic fibers
Authors: Simmons T. A. , Avery J. K.
Published: April 2006

Abstract The staining affinity of electron dense stains to mouse palatal elastic fibers and periodontal oxytalan fibers was assessed and compared. Tissues were stained routinely with uranyl acetate and lead citrate or with elastic tissue stains including: (1) silver tetraphenylporphine sulfonate, (2) tannic acid technique, and (3) a high iron diamine sequence. Staining results were assessed with an electron microscope. Palatal elastic fibers demonstrated staining affinity to all elastic stain techniques. Oxytalan fibers did not demonstrate affinity to elastic fiber stains used. Based on electron dense stains, elastic and oxytalan fibers were dissimilar, in contrast to results reported utilizing light microscopic stains.