bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of TGF‐β isoforms and their receptors during mineralized nodule formation by rat periodontal ligament cells in vitro
Authors: Chien Hua‐Hong , Lin Wen‐Lang , Cho Moon‐II
Published: July 2006

Transforming growth factor‐betas (TGF‐βs) and bone morphogenetic proteins (BMPs), members of a TGF‐β superfamily, are known to play an important role in osteogenic cell differentiation and consequently bone formation. We have reported previously that periodontal ligament (PDL) cells differentiate and form mineralized nodules when cultured in the presence of dexamethasone (Dex), β‐glycerophosphate (GP) and ascorbic acid (AA). To understand the roles of TGF‐β isoforms (TGF‐β1, 2 and 3) and TGF‐β type 1 receptors (activin receptor‐like kinase (ALK)‐2, ‐3, ‐5 and ‐6) in PDL cell differentiation, their expression was investigated using Northern blot analysis. Rat PDL cells, derived from coagulum in the tooth socket, were cultured in the presence of Dex (5 μM), GP (10 mM) and AA (50 μg/ml) for up to 21 d. Total RNA was isolated from PDL cells after 0, 7, 14 and 21 d and used for Northern blot analysis of mRNAs for matrix proteins, TGF‐β isoforms and their receptors using 32P‐labeled cDNAs as probes. Four stages showing distinct morphological characteristics and matrix expression during development of mineralized nodules were identified. Type I collagen (Col I) and SPARC (secreted protein. acidic and rich in cysleine) mRNAs were expressed at the confluent stage, but decreased during the mineralization stage. Osteopontin (OPN) and alkaline phosphatase (ALP) transcripts were initially observed at multilayer stage, while bone sialoprotein (BSP) and osteocalcin (OC) at the nodule stage and all 4 were expressed thereafter. TGF‐β1 mRNA expression increased with the progression of PDL cell differentiation, while a relatively high level of TGF‐β3 transcript decreased slightly during their differentiation. TGF‐β2 mRNA was not expressed. The expression of TGFβ‐RI mRNA decreased, whereas that of TGFβ‐RIII increased dramatically with PDL cell differentiation. TGFβ‐RII gene activities remained high throughout all stages. ALK‐2, ALK‐3 and ALK‐6 mRNA expression increased with the progression of PDL cell differentiation, suggesting that these receptors may play important roles in Dex‐induced PDL cell differentiation and mineralized nodule formation.
Graft of autologous fibroblasts in gingival tissue in vivo after culture in vitro preliminary study on rats
Authors: Simain‐Sato F. , Lahmouzi J. , Heinen E. , Defresne M. P. , De Pauw‐Gillet M. C. , Grisar Th. , Legros J. J. , Legrand R.
Published: July 2006

Several grafting techniques and guided tissue regeneration techniques (GTR) have been well‐developed in periodontal surgery. However, these techniques could induce pain and side effects, such as a gingival recession during the healing period following the therapy. The graft of a small autologous connective tissue, using non‐invasive surgical techniques could yield several benefits for the patients. Our preliminary study explores the feasibility of collecting healthy gingival tissues, culturing them in vitro to amplify rat gingival fibroblasts (RGF) and inoculating the obtained cells into autologous rat gingival tissues in vivo. Gingival tissues samples were cultured as explains as described by Freshney et al. and Adolphe. Confluent cells surrounding explants were detached after 7 d of culture from Petri dishes using 0.05% trypsin and designated “first transferred cells” (T1). At the third passage (T3), cells cultured as monolayer were either examined under microscopy ‐ phase contrast, scanning, or transmission electron ‐ or numerated after trypan blue exclusion test. Autologous RGF labelled with fluorochrome were inoculated at the vestibular and palatine site of gingival tissue close to the superior incisors. In this preliminary study, 12 Wistar rats were used; for each, 2 biopsies were dissected and fixed for phase contrast or fluorescence microscopy. On d 1, 3 and 7 after injection in rat gingival tissues, fluorochrome‐labelled cells could be detected in all these.
Milestones in periodontal research and the remaining critical issues
Authors: Page Roy C.
Published: July 2006

A significant recent development in periodontal research has been the convergence of basic and clinical research resulting in a logarithmic increase in the rate of progress. Scientific consensus has been reached in many areas. In most populations, moderate to severe periodontilis affects a relatively small segment of adults who are at high risk. The microbial etiology is accepted and the identity of the major pathogenic bacterial species is known. The mechanisms through which resistant individuals successfully fend off the microbial challenge are known, and the immuno‐inflammatory pathways activated by bacteria that underlie destruction of the alveolar bone and the connective tissues of the periodontium are reasonably well understood. The evidence shows that these pathways are held in common by all forms of periodontitis. Therapeutic modulation of these pathways is now possible, and new treatments based on such modulation are now becoming available. Although bacteria are essential for disease to occur, they are insufficient; a susceptible host is also necessary. Host susceptibility, disease progression and response to treatment are determined predominantly by heredity and environmental and acquired risk factors. Some of these can be changed while others are immutable. Concepts and procedures for treatment are generally scientifically based and appropriately applied. Preventive measures are largely successful and widely practiced in industrialized countries. Clearly, control of these ancient chronic diseases is now within our reach. In spite of the tremendous progress, many unresolved issues remain. The purpose of this paper is to summarize some of the major accomplishments of periodontal research, and identify and discuss some of the more important critical issues that still need to be addressed.
Interleukin‐1 genotypes and the association between periodontitis and cardiovascular disease
Authors: Kornman Kenneth S. , Pankow James , Offenbacher Steven , Beck James , di Giovine Francesco , Duff Gordon W.
Published: July 2006

An epidemiological association between periodontitis and cardiovascular disease has been reported in multiple studies. Various mechanisms have been proposed as potential explanations for this association, including a common factor that predisposes certain individuals to a hyper‐responsive inflammatory response. Variations in the genes that regulate the interleukin‐1 (IL‐1) response have been associated with both periodontal disease and cardiovascular disease. New data indicate that one pattern of IL‐1 genetic polymorphisms, characterized by the IL‐1 A (+ 4845) and IL‐1 B (+ 3954) markers, is associated with periodontitis but not certain measures of atherosclerosis. Another IL‐1 genetic pattern, characterized by the IL‐1 B (‐511) and IL‐1RN (+ 2018) markers, is associated with atherosclerotic plaque formation, as measured by angiography and arterial wall thickness, but not periodontitis. These two patterns also have different functional implications relative to IL‐1 biological activity. Studies of IL‐1 gene polymorphisms, atherosclerotic plaque instability and cardiovascular clinical events are in progress. Hypothetical models are presented to explain how IL‐1 genetic factors may be involved in cardiovascular disease.
Potential mechanisms of susceptibility to periodontitis in tobacco smokers
Authors: Palmer R. M. , Scott D. A. , Meekin T. N. , Poston R. N. , Odell E. W. , Wilson R. F.
Published: July 2006

Tobacco smoking is probably the most important, controllable environmental risk factor in periodontitis. It results in changes in the vascular, inflammatory, immune and healing responses. The degree of exposure to tobacco smoking can be measured in pack years or by measuring serum cotinine and nicotine levels. In a previous paper we reported elevated levels of serum soluble intercellular adhesion molecule‐1 (sICAM‐1) in smokers, regardless of periodontal status. Elevated sICAM‐1 has been found to be a risk marker for cardiovascular disease. In the present paper we report the short‐term effects of an episode of smoking on blood flow and levels of sICAM‐1. Human volunteers included non‐smokers, light smokers and heavy smokers. Relative blood flow was monitored in the gingivae and forehead skin using a laser Doppler flowmeter and serum levels of sICAM‐1, cotinine and nicotine measured before during and up to 60 min following an episode of smoking. We could not provide evidence to support the theory that there is localized vasoconstriction within the gingival tissues. In contrast, there was a significant increase in blood flow in the forehead skin of light smokers which was not observed in non‐smoking controls or in heavy smokers, suggesting a long‐term tolerance in this latter group. The level of sICAM‐1 remained unchanged during this episode, further suggesting a long‐term effect. In a parallel group of subjects, we were able to demonstrate a direct significant correlation between sICAM and serum cotinine levels. These observations may be relevant to aetiologicat mechanisms in periodontitis and other stnoking‐associated diseases.
Staphylococcus aureus‐Muoed inflammation and bone destruction in experimental models of septic arthritis
Authors: Josefsson Elisabet , Tarkowski Andrej
Published: July 2006

Staphylococcus aureus is the most common cause of septic arthritis. This disease often leads to severe joint destruction and high mortality. An experimental model of S. aureus arthritis has been developed to study the course of inflammation and joint destruction, to elucidate the role of bacteria] and host factors for joint pathology and mortality, and to develop therapeutical and preventive devices against septic arthritis and sepsis. Results show that the innate immune system is crucial in defending the host against staphylococcal infection while components of the specific immune system, T and B lymphocytes and their products, are detrimental to the host, mediating joint destruction and increasing mortality rates. Staphytococcal capsule polysaccharides, toxins, cell wall‐attached adhesins and possibly also the chromosomal DNA are virulence determinants in S. aureus arthritis. Several vaccine candidates have recently been described which protects against staphylococcal infections, e.g. staphylococcal surface polysaccharides, enterotoxins devoid of their superantigenic properties and collagen adhesin. There are also new approaches suggested for treatment of ongoing infections, such as the combined use of antibiotics and corticosteroids.
Evidence and a novel hypothesis for the role of dendritic cells and Porphyromonas gingivalis in adult periodontitis
Authors: Cutler Christopher W. , Jotwani Ravi , Palucka Karolina A. , Davoust Jean , Bell Diana , Banchereau Jacques
Published: July 2006

We have proposed a novel overall hypothesis and approach to understanding the pathophysiology of adult periodontitis, one of the most common diseases that afflicts the US population. While mortality of the dentition is the most familiar outcome of adult periodontitis, its links with other more severe diseases, including coronary artery disease, respiratory diseases and pre‐term labor, cannot be ignored We have called attention to the many intriguing parallels between adult periodontitis and contact hypersensitivity (GHS). CHS is among the most commor of dermatoses that afflicts mankind and one of the most intensively studied of in vivo immune responses. Both adult periodontitis and CHS target the host integument (gingiva or skin) and appear to involve the activation and sensitization of similar subsets of antigen capture and presenting cells, the dendritic cells (DCs), as well as similar T cell subsets. DCs have been termed “nature's adjuvant”, being more efficient at antigen‐presentation than macrophages or B cells and the only antigen‐presenting cells that can stimulate naive T cells to proliferate. This immunostimulatory capacity can also have detrimental effects for the host, as typified by graft‐vs.‐host disease and CHS responses. Both AP and CHS involve a predominantly destructive T cell response mediated by both regulatory and effector T cells. In the present paper, we show intriguing evidence that Porphyromonas gingivalis is a unique pathogen in this regard, able to infect, sensitize and activate DCs in vitro and, probably, in situ. Many questions about the role of P. gingivalis‐sensitized DCs in adult periodontitis, and of the parallels between adult periodontitis and CHS, however, remain to be answered.
Controlled delivery of inductive proteins, plasmid DNA and cells from tissue engineering matrices
Authors: Murphy William L. , Mooney David J.
Published: July 2006

It has been estimated that half the annual health care budget in the United States is spent on patients suffering from tissue loss and late stage organ failure. Critical limitations inherent in traditional therapies call for novel tissue and organ replacement strategies. This paper discusses development of biomaterials for conductive, inductive and cell‐based tissue replacement strategies. Biodegradable polymer scaffolds can be used as space‐filling matrices for tissue development and barriers to migration of epithelial cells in tissue conductive approaches. Inductive approaches involve sustained delivery of bioactive factors, such as protein growth factors and DNA, to alter cell function in localized regions. Factors can be released from highly porous polymer scaffolds to allow factor delivery and tissue development to occur in concert. Cell‐based approaches involve seeding of cells onto polymeric scaffolds in vitro and subsequent transplantation of the scaffold. New scaffold materials are being developed that address specific tissue engineering design requirements, and in some cases attempt to mimic natural extracellular matrices. These strategies together offer the possibility of predictably forming specific tissue structures, and may provide solutions to problems such as periodontal ligament detachment, alveolar bone resorption and furcation defects.
Regeneration of periodontal tissues by basic fibroblast growth factor
Authors: Murakami S. , Takayama S. , Ikezawa K. , Sltimabukuro Y. , Kitamura M. , Nozaki T. , Terashima A. , Asano T. , Okada H.
Published: July 2006

Several growth factors (or cytokines) have recently received attention because of their ability to actively regulate various cellular functions of periodontal ligament (PDL) cells and the effects of topical application of such factor(s) on periodontal tissue regeneration has been evaluated. In this study, we examined the role of basic fibroblast growth factor (bFGF) in the wound healing and regeneration of periodontal tissues. Alveolar bone defects (such as 2‐wall, 3‐wall and furcation class II bone defects) were created surgically in beagle dogs and primates. Recombinant bFGF was topically applied to the artificial bony defects. Six or 8 wk after application, the periodontal regeneration was morphologically and histomorphometrically analyzed. In all sites where bFGF was applied, significant periodontal ligament formation with new cementum deposits and new bone formation was observed in amounts greater than in the control sites. We found it noteworthy that no instances of epithelial down growth, ankylosis or root resorption were observed in the bFGF sites. In vitro studies demonstrated that bFGF enhances the proliferative responses of human PDL cells, which express FGF receptor‐1 and ‐2, but inhibits the induction of alkaline phosphatase activity and mineralized nodule formation by PDL cells. Interestingly, we observed that the mRNA level of laminin in PDL cells, which plays an important role in angiogenesis, was specifically upregulated by bFGF stimulation, but that of type I collagen was downregulated. The present study demonstrates that bFGF can be applied as one of the therapeutic modalities which actively induce periodontal tissue regeneration. The results of in vitro studies suggest that by suppressing the cytodifferentiation of PDL cells into mineralized tissue forming cells, bFGF may play important roles in wound healing by promoting angiogenesis and inducing the growth of immature PDL cells, and may in turn accelerate periodontal regeneration.
Effect of prostaglandin E2 on recombinant human bone morphogenetic protein‐2‐stimulated osteoblastic differentiation in human periodontal ligament cells
Authors: Taktguchi T. , Kobayashi M. , Nagashima C. , Yamaguchi A. , Nishihara T. , Hasegawa K.
Published: July 2006

Recombinant human (rh) bone morphogenetic protein‐2 (BMP‐2) stimulates osteoblastic differentiation in cells isolated from human periodontal ligament (HPLC), and this action of rhBMP‐2 may be modulated by prostaglandins (PGs), which are local regulatory factors in the bone metabolism. In the present study, we investigated the effect of prostaglandin E2 (PGE2) on rhBMP‐2‐stimulated osteoblastic differentiation in cultured HPLC. rhBMP‐2 (500 ng/ml)‐stimulated alkaline phosphatase (ALPase) activity was enhanced by simultaneous treatment with low concentrations (10−10‐10−8 M) of PGE2, whereas a high concentration (10−6 M) of PGE2 suppressed it. rhBMP‐2 did not induce cyclo‐oxygenase‐2 (COX‐2) mRNA expression or subsequent PGE2 production, whereas it remarkably suppressed rhIL‐1β‐induced COX‐2 mRNA expression and PGE2 production. The rhBMP‐2 action on osteoblastic differentiation in HPLC was also enhanced by co‐treatment with 0.25 to 25 ng/ml of rh interleukin‐1β (IL‐1β). The ALPase activity stimulated by simultaneous treatment with rhBMP‐2 and rhIL‐1β was partially inhibited by addition of 10−6 M of indomethacin, which completely inhibited rhIL‐lβ‐induced PGE2 production. These results reveal that PGE2 at different concentrations exerts a biphasic effect on BMP‐2‐stimulated osteoblastic differentiation in HPLC, BMP‐2 inhibits IL‐1β‐induced PGE2 production through suppressing COX‐2 expression, and the BMP‐2‐stimulated osteoblastic differentiation may be enhanced by the endogenous PGE2 induced by BMP‐2 and IL‐1β. These suggest that BMP‐2 action on osteoblastic differentiation in HPLC may be modulated by PGE2 in autocrine and paracrine fashions.
Comparison of gingival and peripheral blood T cells among patients with periodontitis suggests skewing of the gingival T cell antigen receptor Vβ repertoire
Authors: Karimzadeh Kian , Morrison John , Zadeh Homayoun H.
Published: July 2006

The present study investigated the expression of different variable regions of T cell receptor β‐chain (Vβ) among functional subsets of T cells, i.e. CD45RO+ (activated/memory), CD4+ and CD8+in gingiva and peripheral blood of patients with periodontitis. Gingival tissue specimens (n= 25) and peripheral blood were procured from 18 patients with periodontitis during periodontal surgery or extraction. Single‐cell suspensions of gingival tissues were made by enzymatic digestion. These cells were immunofluorescently labeled with a panel of monoclonal antibodies specific for 18 TCR Vβ regions, in concert with markers for various T cell subsets. The cells were then analyzed with 3‐color multivariate flow cytometry. Results demonstrated that a significantly higher proportion of T cells in gingiva expressed Vβ5.2 (0.0005), Vβ6 (0.0007) and Vβ9 (0.003) regions compared to those in peripheral blood. Comparison of CD45RO+ (activated/memory) and CD45RO− (naïve) subsets of gingival T cells revealed differences in the expression of TCR Vβ regions. Vβ5.2 expression was significantly higher among CD45RO+ gingival T cells (p= 0.004), whereas Vβ14 expression was elevated among the CD45RO− subset relative to peripheral blood (p= 0.008). Analysis of TCR Vβ region expression among CD4+ and CD8+ subsets did not reveal any statistically significant differences between gingiva and peripheral blood, although some Vβ regions approached significance. Collectively, these results demonstrate that the T cell repertoire in the gingival compartment differs significantly from that in the peripheral blood. Furthermore, since the skewing of TCR Vβ was observed among naive, as well as activated/memory T cells, it is likely that both developmental and environmental factors are influential in shaping the gingival TCR repertoire in patients with periodontitis. Elucidation of the cause of the skewed expression of T cell receptors in gingiva can provide insights into the specificity of T cells in periodontitis.
Molecular genetics and nomenclature of proteases of Porphyromonas gingivalis
Authors: Curtis M. A. , Kuramitsu H. K. , Lantz M. , Macrina F. L. , Nakayama K. , Potempa J. , Reynolds E. C. , Aduse‐Opoku J.
Published: July 2006

The strategies used by bacterial pathogens to establish and maintain themselves in the host represent one of the fundamental aspects of microbial pathogenesis. Characterization of these strategies and the underlying molecular machinery offers new opportunities both to our understanding of how organisms cause disease in susceptible individuals and to the development of novel therapeutic measures designed to undermine or interfere with these determinants of successful survival. With respect to the microbial aetiology of the periodontal diseases, a growing body of evidence suggests that the proteolytic enzymes of Porphyromonas gingivalis represent key survival and, by extrapolation, virulence determinants of this periodontal bacterium. This in turn has led to international efforts to characterize these enzymes at the gene and protein level. Approximately 20 protease genes of P. gingivalis with different names and accession numbers have been deposited in the gene databases and a correspondingly heterogeneous nomenclature system is employed for the products of these genes in the literature. However, it is evident, through comparison of these gene sequences and through gene inactivation studies, that the genetic structure of the proteases of this organism, particularly those with specificity for arginyl and lysyl peptide bonds, is less complicated than originally thought. The major extracellular and surface associated arginine specific protease activity is encoded by 2 genes which we recommend be designated rgpA and rgpB (arg‐gingipains A & B). Similarly we recommend that the gene encoding the major lysine specific protease activity is designated kgp (lys‐gingipain). These three genes, which account for all the extracellular/surface arginine and lysine protease activity in P. gingivalis, belong to a family of sequence‐related proteases and haemagglutinins.
The in vitro effects of cetyltrimethylammonium naproxenate on oral and pharyngeal microorganisms of various ecological niches
Authors: Pilloni Argenia Paola , Buttini Giovanni , Giordano Bruna , Iovene Maria Rosaria , di Salvo Riccardo , Buommino Elisabetta , Tufano Maria Antonietta
Published: July 2006

The purpose of this study was to determine the in vitro susceptibility to cetyltrimethylammonium naproxenate for various aerobic and anaerobic micro‐organisms responsible for oral and pharyngeal diseases by assessing the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) or minimum fungicidal concentrations (MFCs) and by determining kill‐times. The MICs of cetyltrimethylammonium naproxenate for 46 tested strains (25 reference strains and 21 clinical isolates) ranged from 8 to 500 μg/ml. The MIC was found to be 31.25 μg/ml for 36% of the reference strains. Even lower MIC values (15.63 μg/ml) were observed for some anaerobic strains, for Haemophilus influenzae and for Candida tropicalis. MIC and MBC values corresponded for the majority of strains tested while the MFC for C. tropicalis and C. albicans was much higher. Only 9.5% of the clinical isolates gave a MIC value of 31.25 μg/ml. Enterococcus faecalis, Streptococcus pyogenes and Staphylococcus aureus showed MIC at 62.5 μg/ml. The MIC and MBC values among the isolates were comparable, while the MFC value for the yeasts was greater. A concentration of 125 μg/ml of cetyltrimethylammonium naproxenate inhibited the growth of all bacteria, except Enterobacteriaceae and Pseudomonaceae, and yeasts. Cetyltrimethylammonium naproxenate shows very rapid kill‐time for S. sanguis (0″), and rapid (15″) for S. pyogenes, S. dysgalactiae and S. mutans and for Moraxella catarrhalis, while a longer kill‐time was necessary for the other microbes tested.
Responses to Fire in Selected Tropical Dry Forest Trees1
Authors: Otterstrom Sarah M. , Schwartz Mark W. , Velázquez‐Rocha Ileana
Published: July 2006

Fire is a frequent disturbance in the tropical dry forests of Central America, yet very little is known about how native species respond to such events. We conducted an experimental burn in a tropical dry forest of western Nicaragua to evaluate plant responses to fire with respect to survivorship and recruitment. Measurements of woody vegetation of all size classes were carried out prior to the prescribed burn and three successive years post fire. We selected the 15 most abundant species <10 cm DBH to assess percent survivorship and sprouting responses post fire. Changes in seedling densities for these 15 most abundant species and the 15 least abundant species were analyzed using a repeated measure ANOVA. We also assessed changes in seedling densities for three species of international conservation concern. We found three major fire‐coping strategies among common dry forests plants: resisters (low fire‐induced mortality), resprouters (vigorous sprouting), and recruiters (increased seeding post‐fire). While survivorship was generally high relative to tropical moist forest species, those species with lower survivorship used either seeding or sprouting as an alternative strategy for persisting in the forest community. Seed dispersal mechanisms, particularly wind dispersal, appear to be an important factor in recruitment success post‐fire. Burn treatment led to a significant increase in the density of seedlings for two species of conservation concern: Guaiacum sanctum and Swietenia humilis. Results of this study suggest that common dry forest species in western Nicaragua are fire tolerant. Further study of individual species and their fire responses is merited.
Mangrove Seedling Net Photosynthesis, Growth, and Survivorship are Interactively Affected by Salinity and Light1
Authors: López‐Hoffman Laura , DeNoyer Jeanne L. , Monroe Ian E. , Shaftel Rebecca , Anten Niels P. R. , Martínez‐Ramos Miguel , Ackerly David D.
Published: July 2006

We hypothesized that salinity and light interactively affect mangroves, such that net photosynthesis, growth, and survivorship rates increase more with increase in light availability at low than high salinity. Using greenhouse and field experiments, we determined that net photosynthesis, growth rates, and size increased more with light at low than high salinity. At high salinity, the ratio of leaf respiration to assimilation increased fourfold, suggesting that salinity may have contributed to declines in net photosynthesis. Stomatal conductance, leaf‐level transpiration, and internal CO2 concentrations were lower at high salinity. Ratios of root mass to leaf mass were higher at high salinity. Stomatal limitations and increased respiratory costs may explain why at high salinity, the seedlings did not respond to increased light availability with increased net photosynthesis. Increased root mass relative to leaf mass suggests that at high salinity, either water or nutrient limitations may have prevented the seedlings from increasing growth with increasing light availability. At both low‐ and high‐salinity zones in the field, seedling survivorship increased with light availability, and the effect of light was stronger at low salinity. However, at low light, survivorship was higher at high than low salinity, indicating that there may be a trade‐off between survivorship and growth. The interactive effects observed in the greenhouse were robust in the field, despite the presence of other factors in the field such as inundation and nutrient gradients and herbivory. This study provides a robust test of the hypothesis that salinity and light interactively effect mangrove seedling performance.
Cockscomb Revisited: Jaguar Diet in the Cockscomb Basin Wildlife Sanctuary, Belize1
Authors: Weckel Mark , Giuliano William , Silver Scott
Published: July 2006

The Cockscomb Basin Wildlife Sanctuary, Belize was established in 1986 following Rabinowitz and Nottingham's 1986 study on jaguar diet and distribution. In 2002, we reexamined jaguar diet following two decades of mitigated human hunting of jaguar prey. We observed high overlap between historical and current jaguar diet constructs. Nine‐banded armadillo remained the most frequently consumed prey item. However, collared peccary consumption increased by nearly 20 percent while dietary breadth decreased by 60 percent presumably reflecting increased prey availability following reduced human hunting pressure.
Biological activity of rainbow trout Ea4‐peptide of the pro‐insulin‐like growth factor (pro‐IGF)‐I on promoting attachment of breast cancer cells (MDA‐MB‐231) via α2‐ and β1‐integrin
Authors: Siri Sineenat , Chen Maria J. , Chen Thomas T.
Published: July 2006

E‐peptide of pro‐IGF‐I was considered as biologically inactive. We have demonstrated that rainbow trout (rt) Ea4‐peptide exerted biological activities in several established tumor cell lines [Chen et al., 2002; Kuo and Chen, 2002]. Here we report the activity of rtEa4‐peptide in promoting attachment of human breast cancer cells (MDA‐MB‐231). While rtEa2‐, rtEa3‐, and rtEa4‐peptides enhanced the attachment of MDA‐MB‐231 cells in a dose dependent manner, rtEa4‐peptide possessed the highest activity. Antibodies specific to α2 and β1 integrins significantly inhibited the attachment of cells to rtEa4‐peptide coated‐plates by 40%. In addition, rtEa4‐peptide induced the expression of fibronectin 1 and laminin receptor genes in MDA‐MB‐231 cells. Blocking new protein synthesis by cycloheximide significantly reduced the attachment of MDA‐MB‐231 cells to rtEa4‐peptide coated wells by 50%. These results suggest that rtEa4‐peptide may promote cell attachment by interacting with α2/β1 integrin receptors at the cell surface and by inducing the expression of fibronectin 1 and laminin receptor genes. Expression of fibronectin 1 gene induced by rtEa4‐peptide in MDA‐MB‐231 cells was abolished by inhibitors of PI3K, PKC, Mek1/2, JNK1/2, and p38 MAPK signaling transduction molecules. These results suggested that induction of fibronectin 1 gene expression in MDA‐MB‐231 cells by rtEa4‐peptide may be mediated via PI3K, PKC, Mek1/2, JNK1/2, and p38 MAPK signal transduction molecules. J. Cell. Biochem. 99: 1524–1535, 2006. © 2006 Wiley‐Liss, Inc.
Functional analysis of CBP/p300 in embryonic orofacial mesenchymal cells
Authors: Warner D.R. , Pisano M.M. , Greene R.M.
Published: July 2006

CREB binding protein (CBP) and the close structural homolog, p300, are nuclear coactivators of multiple signaling pathways that play important roles in embryonic development and cellular homeostasis. TGFβ regulates the proliferation rate of many cell types and has been demonstrated to inhibit the growth rate of mouse embryonic maxillary mesenchymal (MEMM) cells. The role of CBP and p300 in TGFβ‐mediated control of proliferation of MEMM cells was thus investigated using an in vitro gene knockdown approach. TGFβ reporter assays demonstrated that p300 mRNA knockdown via targeted siRNAs led to a reduction in the response to TGFβ, whereas knockdown of CBP by the same approach had an insignificant effect. In MEMM cell proliferation assays, siRNA‐mediated knockdown of CBP and/or p300 had little impact upon TGFβ‐mediated growth inhibition; however, the basal rate of proliferation was increased. Inhibition of p300 activity via overexpression of a dominant‐negative mutant (p300ΔC/H3) led to significant inhibition of TGFβ‐mediated activation of p3TP‐lux. As with the siRNA knockdown approach, p300ΔC/H3 also increased the basal rate of cell proliferation of MEMM cells. CBP/p300 siRNA knockdown had a significant but incomplete inhibition of TGFβ‐induction of matrix metalloproteinase‐9 (gelatinase B) expression. These data demonstrate that p300 is involved in Smad‐mediated transcription of p3TP‐lux, however, its role (and that of CBP) in biological processes such as the control of cell proliferation and extracellular matrix metabolism is more complex and may be mediated via mechanisms beyond coactivator recruitment. J. Cell. Biochem. 99: 1374–1379, 2006. © 2006 Wiley‐Liss, Inc.
Differential effects of matrix and growth factors on endothelial and fibroblast motility: Application of a modified cell migration assay
Authors: van Horssen Remco , Galjart Niels , Rens Joost A.P. , Eggermont Alexander M.M. , ten Hagen Timo L.M.
Published: July 2006

Cell migration is crucial in virtually every biological process and strongly depends on the nature of the surrounding matrix. An assay that enables real‐time studies on the effects of defined matrix components and growth factors on cell migration is not available. We have set up a novel, quantitative migration assay, which enables unharmed cells to migrate along a defined matrix. Here, we used this so‐called barrier‐assay to define the contribution of fibronectin (FN) and Collagen‐I (Col‐I) to vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and lysophosphatidic acid (LPA)‐induced cell migration of endothelial cells (EC) and fibroblasts. In EC, both FN and Col‐I stimulated migration, but FN‐induced motility was random, while net movement was inhibited. Addition of bFGF and VEGF overcame the effect of FN, with VEGF causing directional movement. In contrast, in 3T3 fibroblasts, FN stimulated motility and this effect was enhanced by bFGF. This motility was more efficient and morphologically completely different compared to LPA stimulation. Strikingly, directional migration of EC was not paralleled by higher amounts of stable microtubules (MT) or an increased reorientation of the microtubule‐organizing centre (MTOC). For EC, the FN effect appeared concentration dependent; high FN was able to induce migration, while for fibroblasts both low and high concentrations of FN induced motility. Besides showing distinct responses of the different cells to the same factors, these results address contradictive reports on FN and show that the interplay between matrix components and growth factors determines both pattern and regulation of cell migration. J. Cell. Biochem. 99: 1536–1552, 2006. © 2006 Wiley‐Liss, Inc.
Centrosome function in normal and tumor cells
Authors: Sankaran Satish , Parvin Jeffrey D.
Published: July 2006

Centrosomes nucleate microtubules that form the mitotic spindle and regulate the equal division of chromosomes during cell division. In cancer, centrosomes are often found amplified to greater than two per cell, and these tumor cells frequently have aneuploid genomes. In this review, we will discuss the cellular factors that regulate the proper duplication of the centrosome and how these regulatory steps can lead to abnormal centrosome numbers and abnormal mitoses. In particular, we highlight the newly emerging role of the Breast Cancer 1 (BRCA1) ubiquitin ligase in this process. J. Cell. Biochem. 99: 1240–1250, 2006. © 2006 Wiley‐Liss, Inc.
Phosphatidylinositol 3‐kinase/Akt auto‐regulates PDGF‐BB‐stimulated interleukin‐6 synthesis in osteoblasts
Authors: Hanai Yoshiteru , Tokuda Haruhiko , Ohta Toshiki , Matsushima‐Nishiwaki Rie , Takai Shinji , Kozawa Osamu
Published: July 2006

It has been reported that platelet‐derived growth factor (PDGF)‐BB stimulates the synthesis of interleukin (IL)‐6 in osteoblasts. In the present study, we investigated whether the phosphatidylinositol 3‐kinase (PI3K)/Akt is involved in the PDGF‐BB‐induced IL‐6 synthesis in osteoblast‐like MC3T3‐E1 cells. PDGF‐BB markedly induced the phosphorylation of Akt and GSK‐3β. Akt inhibitor, 1L‐6‐hydroxymethyl‐chiro‐inositol 2‐(R)‐2‐O‐methyl‐3‐O‐octadecylcarbonate, significantly amplified the synthesis of IL‐6 by PDGF‐BB. The PDGF‐BB‐induced GSK‐3β phosphorylation was suppressed by the Akt inhibitor. The IL‐6 synthesis stimulated by PDGF‐BB was markedly enhanced by LY294002 and wortmannin, inhibitors of PI3K. Wortmannin and LY294002 suppressed the PDGF‐BB‐induced phosphorylation of Akt and GSK‐3β. Taken together, these results strongly suggest that PI3K/Akt negatively regulates the PDGF‐BB‐stimulated IL‐6 synthesis in osteoblasts. J. Cell. Biochem. 99: 1564–1571, 2006. © 2006 Wiley‐Liss, Inc.
Mechanism of 24,25‐dihydroxyvitamin D3‐mediated inhibition of rapid, 1,25‐dihydroxyvitamin D3‐induced responses: Role of reactive oxygen species
Authors: Nemere Ilka , Wilson Cody , Jensen Wendy , Steinbeck Marla , Rohe Ben , Farach‐Carson Mary C.
Published: July 2006

In intestine, 24,25(OH)2D3, which is made under conditions of calcium‐, phosphate‐, and 1,25(OH)2D3 sufficiency, inhibits the stimulatory actions of 1,25(OH)2D3 on phosphate and calcium absorption. In the current work, we provide evidence that 24,25(OH)2D3‐mediated signal transduction occurs mechanistically through increased H2O2 production which involves binding of 24,25(OH)2D3 to catalase and resultant decreases in enzyme activity. Physiological levels of H2O2 mimicked the action of 24,25(OH)2D3 on inhibiting 1,25(OH)2D3‐stimulated phosphate uptake in isolated enterocytes. Moreover, the molecular basis of such inhibition was suggested by the presence of two thioredoxin domains in the 1,25D3‐MARRS protein/ERp57: Exposure of cells to either 24,25(OH)2D3 or H2O2 gradually reduced 1,25(OH)2D3 binding to 1,25D3‐MARRS protein, between 10 and 20 min of incubation, but not to VDR. Feeding studies with diets enriched in the antioxidants vitamins C and E showed that net phosphate absorption in vivo nearly doubled relative to chicks on control diet. Antioxidant diets also resulted in increased [3H]1,25(OH)2D3 binding to both 1,25D3‐MARRS and VDR, suggesting benefits to both transcription‐ and membrane‐initiated signaling pathways. Intriguingly, phosphorous content of bones from birds on antioxidant diets was reduced, suggesting increased osteoclast activity. Because mature osteoclasts lack VDR, we analyzed a clonal osteoclast cell line by RT‐PCR and found it contained the 1,25D3‐MARRS mRNA. The combined data provide mechanistic details for the 1,25(OH)2D3/24,25(OH)2D3 endocrine system, and point to a role for the 1,25D3‐MARRS protein as a redox‐sensitive mediator of osteoclast activity and potential therapeutic target. J. Cell. Biochem. 99: 1572–1581, 2006. © 2006 Wiley‐Liss, Inc.
The effects of a mutant p53 protein on the proliferation and differentiation of PC12 rat phaeochromocytoma cells
Authors: Fábián Zsolt , Vecsernyés Mónika , Pap Marianna , Szeberényi József
Published: July 2006

PC12 rat phaeochromocytoma cells show neuronal differentiation upon NGF treatment. NGF induces prolonged activation of the Ras/Raf/MEK/ERK pathway in which the 42/44 kDa mitogen‐activated protein kinases (MAPKs), ERK 1 and 2 are thought to be the key mediators of the differentiation signals. Activation of ERKs leads to the increased transcription of early response genes resulting in cell cycle arrest. Upon NGF treatment the p53 protein, the most commonly mutated tumor suppressor in human cancers, translocates to the nucleus and may play a role in the mediation of NGF‐induced cell cycle arrest and neuronal differentiation. Here we demonstrate that in PC12 cells expressing both wild‐type and V143A mutant p53 proteins (p143p53PC12 cells), p53‐mediated biological responses are critically influenced. p143p53PC12 cells are not able to cease their proliferation and begin their neuronal differentiation program upon NGF treatment. The presence of mutant p53 also reduces the DNA‐binding activity of endogenous p53 and disturbs the regulatory machinery of p53 including both the phosphorylation of ERK 1/2, p38 and SAPK/JNK MAP kinases and itself. J. Cell. Biochem. 99: 1431–1441, 2006. © 2006 Wiley‐Liss, Inc.
In vivo modulation of epidermal growth factor receptor phosphorylation in mice expressing different gangliosides
Authors: Daniotti Jose L. , Crespo Pilar M. , Yamashita Tadashi
Published: July 2006

We studied in this work the in vivo phosphorylation of the epidermal growth factor receptor (EGFr) in skin from knockout mice lacking different ganglioside glycosyltransferases. Results show an enhancement of EGFr phosphorylation, after EGF stimulation, in skin from Sial‐T2 knockout and Sial‐T2/GalNAc‐T double knockout mice as compared with wild‐type and Sial‐T1 knockout mice. Qualitative analysis of ganglioside composition in mice skin suggest that the increase of EGFr phosphorylation observed in skin from Sial‐T2 knockout and Sial‐T2/GalNAc‐T double knockout mice in response to EGF might not be primary attributed to the expression of GD3 or a‐series gangliosides in mice skin. These studies provide, for the first time, an approach for studying the molecular mechanisms involved in the in vivo regulation of EGFr function by gangliosides. J. Cell. Biochem. 99: 1442–1451, 2006. © 2006 Wiley‐Liss, Inc.
Alpha1‐Antitrypsin Single Dose Adjuvant Therapy for Acute Otitis Media
Authors: Patrick J. Antonelli , Gregory S. Schultz , David J. Sundin , Philip A. Pemberton , Philip J. Barr
Published: July 2006

OBJECTIVES

Proteases have been shown to play a role in the pathogenesis of otitis media. Inhibition of these proteases can improve treatment outcomes in certain conditions. The goal of this study was to determine if intratympanic administration of a single dose of the protease inhibitor, recombinant alpha 1‐antitrypsin (rAAT), can facilitate resolution of acute otitis media (AOM) in the chinchilla.

METHODS AND MEASURES

Pneumococcus was injected into both middle ears of 12 chinchillas. After 3 to 4 days, middle ears were cultured, systemic antibiotics were initiated, and rAAT or its vehicle was administered into the middle ears of all animals. Serial tympanic membrane (TM) scoring, tympanometry, and auditory‐evoked brain stem response testing were performed. Animals were sacrificed at varying timepoints and temporal bones studied for objective measures of OM.

RESULTS

Although not reaching statistical significance, there was a trend to more rapid resolution of AOM in rAAT‐treated ears. Tympanometry, auditory thresholds, and quantitative histologic parameters did not differ between rAAT and vehicle treated ears.

CONCLUSIONS

A single dose of intratympanic rAAT likely does not facilitate the resolution of antibiotic‐treated pneumococcal AOM in the chinchilla model. Serial administration of this protease inhibitor may be necessary to see a significant treatment effect.
Gerbilline Cholesteatoma Development Part III. Increased Proliferation Index of Basal Keratinocytes of the Tympanic Membrane and External Ear Canal
Authors: Steven P. Tinling , Richard A. Chole
Published: July 2006

OBJECTIVE

To quantify the rate of basal cell division for keratinizing epithelium (KE) of the tympanic membrane (TM) and external ear canal (EAC) in spontaneous and induced gerbilline cholesteatomas.

STUDY DESIGN AND SETTING

Cholesteatomas (3 spontaneous and 5 by induction) were labeled with tritiated thymidine for autoradiography and a KE proliferation index (PI) was determined. The PI was defined as the average number of labeled cells/mm overall and per anatomic region.

RESULTS

For all regions combined, the PI was 27.3 in ears with cholesteatoma and 4.1 in normal ears (P < 0.0001). Additionally, there were significant regional differences in the PI in both normal ears and ears with cholesteatoma.

CONCLUSION

The KE of cholesteatomas in gerbils proliferates at approximately 7 times the rate measured in control ears.

SIGNIFICANCE

Hyperproliferation of keratinocytes is a causative factor in the development and progression of spontaneous and experimental cholesteatomas in gerbils.
Long‐Term Results with Operated Sinus Tympani Retraction Cholesteatoma
Authors: Leonetti John P. , Marzo Sam J. , Beauchamp Mary M. , Jellish W. Scott
Published: July 2006

OBJECTIVES

Utilizing an endaural approach, we described the surgical treatment of 29 cases of sinus tympani retraction cholesteatoma in 1996. The purpose of this paper is to provide long‐term results in this group of patients.

STUDY DESIGN AND SETTING

A retrospective chart analysis of 29 previously reported patients was undertaken in an effort to identify hearing results and the risk of cholesteatoma recurrence following sinus tympani retraction surgery.

RESULTS

The follow‐up period ranged from 9 to 16 years (mean of 13.2 years). Speech discrimination (SD) and conductive hearing (CH) decline occurred in 23 of 28 patients, but only on the average of 5.6% and 9 dB throughout the speech frequencies, respectively. Speech discrimination and conductive hearing improved in 5 of 28 patients; one patient was lost to follow‐up. One patient developed a recurrent cholesteatoma requiring a canal wall—down mastoidectomy.

CONCLUSIONS

The endaural approach for sinus tympani cholesteatoma provided stable hearing in most of the patients in this series. One cholesteatoma recurrence required conversion to a canal wall—down mastoidectomy. This developed in a noncompliant patient, whose pars tensa retraction deepened as a result of failure to have his ventilation tube replaced. Semiannual office visits are recommended in patients who undergo this otologic approach for sinus tympani cholesteatoma.
Amplification of CCND1, EMS1, PIK3CA, and ERBB Oncogenes in Ethmoid Sinus Adenocarcinomas
Authors: Gonzalo Nazar , María V. González , Juana María García , José L. Llorente , Juan P. Rodrigo , Carlos Suárez
Published: July 2006

OBJECTIVE

Assess the amplification of CCND1, EMS1, PIK3CA, ERBB1, and ERBB2 oncogenes in ethmoid sinus adenocarcinomas.

STUDY DESIGN AND SETTING

Tissue samples from 13 primary ethmoid adenocarcinomas and 2 recurrences were studied at Hospital Central de Asturias, Oviedo, Spain, between July 1998 and February 2002. A semiquantitative evaluation of CCND1, EMS1, PIK3CA, ERBB1, and ERBB2 amplification was performed by multiplex polymerase chain reaction.

RESULTS

Three (23%) cases presented CCND1 amplification, one of them with a concurrent PIK3CA amplification. EMS1 was amplified in the 2 studied recurrences. ERBB1 was amplified in 1 case (8%), whereas none presented ERBB2 amplification. Oncogenic amplifications were only detected in advanced (stage III) tumors; however, no prognostic value could be shown for them.

CONCLUSIONS

CCND1, EMS1, PIK3CA, and ERBB1 amplifications are uncommon and appear to be late events in the development of ethmoid sinus adenocarcinoma.

SIGNIFICANCE

New information on the carcinogenesis of this infrequent sinonasal tumor is presented.
Inflammatory Pseudotumor Involving the Skull Base: Response to Steroid and Radiation Therapy
Authors: Lee Dong Kyung , Cho Yang‐Sun , Hong Sung Hwa , Chung Won Ho , Ahn Yong Chan
Published: July 2006

OBJECTIVE

To evaluate the response to steroid and radiation therapy in inflammatory pseudotumor (IPT) involving the skull base.

STUDY DESIGN AND SETTING

Eight patients with IPT of the skull base were evaluated. Six patients were diabetic. All patients underwent initial high‐dose steroid therapy. Seven of 8 patients underwent subsequent low‐dose steroid maintenance. Additional low‐dose radiation therapy was performed in 6 patients. We reviewed the medical records and radiologic findings of the patients to evaluate their responses to the steroid and radiation therapy.

RESULTS

In all patients, the initial response to steroid therapy was fair. However, 7 patients showed symptom recurrence after cessation of steroid therapy. In 5 of 6 patients, low‐dose radiation therapy resulted in recurrence. On follow‐up MRI, none of the patients showed complete remission of the disease.

CONCLUSION

This study shows aggressive clinical behavior of IPT involving the skull base and its poor response to steroid therapy and low‐dose radiation therapy. For improving control, more aggressive initial efforts including high‐dose radiation therapy with or without concurrent steroid therapy might play a role.

EBM rating: C‐4